Abdolrahim_2014 ArticleInAPeriodical Elsevier BV 2014 jan International Journal of Plasticity 52 https://doi.org/10.1016%2Fj.ijplas.2013.04.002 33-50 AbdolrahimNiaz ZbibHusseinM BahrDavidF Multiscale modeling and simulation of deformation in nanoscale metallic multilayer systems adhika_crack_2015 ArticleInAPeriodical 2015 Microscopy 64 5 https://doi.org/10.1093/jmicro/dfv032 335-340 AdhikaDamarRastri TanakaMasaki DaioTakeshi HigashidaKenji Crack tip shielding observed with high-resolution transmission electron microscopy aghababaei_micromechanics_2014 ArticleInAPeriodical 2014 May Acta Materialia 69 http://www.sciencedirect.com/science/article/pii/S1359645414000238 https://doi.org/10.1016/j.actamat.2014.01.014 326-342 AghababaeiRamin JoshiShailendraP Micromechanics of tensile twinning in magnesium gleaned from molecular dynamics simulations This work discusses coarse-grained micromechanics of tensile twinning in magnesium (Mg) extracted from molecular dynamics (MD) simulations. We perform MD simulations on Mg single crystal orientations with initial idealized defect structures at temperatures T=5K and 300K. A detailed atomistic analysis reveals that tensile loading along the c-axis of a defective crystal causes an initial incomplete slip ahead of the defect on the first-order pyramidal âØE©c+aâØEplanes, followed by the formation of a {112̄1} twin embryo and basal dislocation. These mechanisms aid the formation of {101̄2} twins, which evolve rapidly while {112̄1} twins disappear. We present a micromechanics picture of the deformation-induced twin structure evolution that is tracked by incorporating a twin orientation analysis (TOA) scheme within Open Visualization Tool. The functional dependencies of the volume fraction (v.f.) and number of twins on the overall plastic strain extracted from this analysis provide a basis to construct kinetic laws for twin evolution in terms of nucleation, growth and coalescence. Preliminary results indicate that {101̄2} v.f. evolution is dominated by twin growth in the presence of defects at room temperature, and it may not be strongly rate dependent. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Akasheh_2007 ArticleInAPeriodical AIP Publishing 2007 aug Journal of Applied Physics 102 3 https://doi.org/10.1063%2F1.2757082 034314 AkashehF ZbibHM HirthJP HoaglandRG MisraA Interactions between glide dislocations and parallel interfacial dislocations in nanoscale strained layers aluru_dynamic_1999 ArticleInAPeriodical 1999 Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 1738 https://doi.org/10.1007/3-540-46691-6_2 21-33 AluruSrinivas SevilgenFatihE Dynamic compressed hyperoctrees with application to the N-body problem Anciaux_2018 ArticleInAPeriodical Elsevier BV 2018 sep Journal of the Mechanics and Physics of Solids 118 https://doi.org/10.1016%2Fj.jmps.2018.05.004 152-171 AnciauxG JungeT HodappM ChoJ MolinariJ.-F. CurtinWA The Coupled Atomistic/Discrete-Dislocation method in 3d part I: Concept and algorithms andersen_molecular_1980 ArticleInAPeriodical 1980 February The Journal of Chemical Physics 72 4 http://aip.scitation.org/doi/10.1063/1.439486 https://doi.org/10.1063/1.439486 2384-2393 AndersenHansC Molecular dynamics simulations at constant pressure and/or temperature In the molecular dynamics simulation method for fluids, the equations of motion for a collection of particles in a fixed volume are solved numerically. The energy, volume, and number of particles are constant for a particular simulation, and it is assumed that time averages of properties of the simulated fluid are equal to microcanonical ensemble averages of the same properties. In some situations, it is desirable to perform simulations of a fluid for particular values of temperature and/or pressure or under conditions in which the energy and volume of the fluid can fluctuate. This paper proposes and discusses three methods for performing molecular dynamics simulations under conditions of constant temperature and/or pressure, rather than constant energy and volume. For these three methods, it is shown that time averages of properties of the simulated fluid are equal to averages over the isoenthalpic–isobaric, canonical, and isothermal–isobaric ensembles. Each method is a way of describing the dynamics of ... andric_new_2017 ArticleInAPeriodical 2017 Journal of the Mechanics and Physics of Solids 106 https://doi.org/10.1016/j.jmps.2017.06.006 315-337 AndricPredrag CurtinWA New theory for Mode I crack-tip dislocation emission A material is intrinsically ductile under Mode I loading when the critical stress intensity KIe for dislocation emission is lower than the critical stress intensity KIc for cleavage. KIe is usually evaluated using the approximate Rice theory, which predicts a dependence on the elastic constants and the unstable stacking fault energy γusf for slip along the plane of dislocation emission. Here, atomistic simulations across a wide range of fcc metals show that KIe is systematically larger (10–30%) than predicted. However, the critical (crack tip) shear displacement is up to 40% smaller than predicted. The discrepancy arises because Mode I emission is accompanied by the formation of a surface step that is not considered in the Rice theory. A new theory for Mode I emission is presented based on the ideas that (i) the stress resisting step formation at the crack tip creates “lattice trapping” against dislocation emission such that (ii) emission is due to a mechanical instability at the crack tip. The new theory is formulated using a Peierls-type model, naturally includes the energy to form the step, and reduces to the Rice theory (no trapping) when the step energy is small. The new theory predicts a higher KIe at a smaller critical shear displacement, rationalizing deviations of simulations from the Rice theory. Specific predictions of KIe for the simulated materials, usually requiring use of the measured critical crack tip shear displacement due to complex material non-linearity, show very good agreement with simulations. An analytic model involving only γusf, the surface energy γs, and anisotropic elastic constants is shown to be quite accurate, serves as a replacement for the analytical Rice theory, and is used to understand differences between Rice theory and simulation in recent literature. The new theory highlights the role of surface steps created by dislocation emission in Mode I, which has implications not only for intrinsic ductility but also for crack tip twinning and fracture due to chemical interactions at the crack tip. Antillon_2019 ArticleInAPeriodical Elsevier BV 2019 mar Acta Materialia 166 https://doi.org/10.1016%2Fj.actamat.2018.12.037 658-676 AntillonE WoodwardC RaoSI AkdimB ParthasarathyTA A molecular dynamics technique for determining energy landscapes as a dislocation percolates through a field of solutes Anwar_Ali_2019a ArticleInAPeriodical Cambridge University Press (CUP) 2019 jan Journal of Materials Research 34 9 https://doi.org/10.1557%2Fjmr.2018.449 1564-1573 AliHashinaParveenAnwar RadchenkoIhor LiNan BudimanArief Effect of multilayer interface through in situ fracture of Cu/Nb and Al/Nb metallic multilayers Anwar_Ali_2019 ArticleInAPeriodical Cambridge University Press (CUP) 2019 mar Journal of Materials Research 34 9 https://doi.org/10.1557%2Fjmr.2019.75 1449-1468 AliHashinaParveenAnwar BudimanArief Advances in In situ microfracture experimentation techniques: A case of nanoscale metal–metal multilayered materials bachurin_dislocation-grain_2010 ArticleInAPeriodical 2010 Acta Materialia 58 16 https://doi.org/10.1016/j.actamat.2010.05.037 5232-5241 BachurinDV WeygandD GumbschP Dislocation-grain boundary interaction in 〈1 1 1〉 textured thin metal films The interaction of lattice dislocations with symmetrical and asymmetrical tilt grain boundaries in 〈1 1 1〉 textured thin nickel films was investigated using atomistic simulation methods. It was found that the misorientation angle of the grain boundary, the sign of the Burgers vector of the incoming dislocation and the exact site where the dislocation meets the grain boundary are all important parameters determining the ability of the dislocation to penetrate the boundary. Inclination angle, however, does not make an important difference on the transmission scenario of full dislocations. Only limited partial dislocation nucleation was observed for the investigated high-angle grain boundary. The peculiarities of nucleation of embryonic dislocations and their emission from tilt grain boundaries are discussed. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. banerjee_influence_2001 ArticleInAPeriodical 2001 Scripta Materialia 44 11 https://doi.org/10.1016/S1359-6462(01)00966-6 2629-2633 BanerjeeRajarshi FainJasonP AndersonPeterM FraserHamishL Influence of crystallographic orientation and layer thickness on fracture behavior of Ni/Ni3Al multilayered thin films Ni/Ni3Al multilayers have been deposited epitaxially and non-epitaxially by UHV magnetron sputtering on 〈001〉 NaCl substrates. Two interfacial orientations were achieved: {001} Ni // {001} Ni3Al, 〈100〉 Ni // 〈100〉 Ni3Al and {111} Ni // {111} Ni3Al, 〈110〉 Ni // 〈110〉 Ni3Al. Under in-plane tensile loading, 〈001〉 oriented multilayers exhibit ductile fracture surface features but 〈111〉 oriented multilayers of the same layer thickness are predominantly brittle. For each orientation, the fracture surface features from 20 nm thick Ni and Ni3Al layers appear to be as ductile or more ductile than those from 120 nm thick layers, but the plastic deformation appears to be more localized. © 2001 Acta Materialia Inc. banerjee_perspectives_2013 ArticleInAPeriodical 2013 Acta Materialia 61 3 https://doi.org/10.1016/j.actamat.2012.10.043 844-879 BanerjeeDipankar WilliamsJC Perspectives on titanium science and technology The basic framework and - conceptual understanding of the metallurgy of Ti alloys is strong and this has enabled the use of titanium and its alloys in safety-critical structures such as those in aircraft and aircraft engines. Nevertheless, a focus on cost-effectiveness and the compression of product development time by effectively integrating design with manufacturing in these applications, as well as those emerging in bioengineering, has driven research in recent decades towards a greater predictive capability through the use of computational materials engineering tools. Therefore this paper focuses on the complexity and variety of fundamental phenomena in this material system with a focus on phase transformations and mechanical behaviour in order to delineate the challenges that lie ahead in achieving these goals. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Bart_k_2013 ArticleInAPeriodical American Physical Society (APS) 2013 may Physical Review B 87 18 https://doi.org/10.1103%2Fphysrevb.87.184115 BartókAlbertP KondorRisi CsányiGábor On representing chemical environments baskes_modified_1994 ArticleInAPeriodical 1994 Modelling and Simulation in Materials Science and Engineering 2 1 http://stacks.iop.org/0965-0393/2/i=1/a=011?key=crossref.768f023be3e16c6dc0487e26ada1743b https://doi.org/10.1088/0965-0393/2/1/011 147-163 BaskesMI JohnsonRA Modified embedded atom potentials for HCP metals Analytic modified embedded atom method (AMEAM) type many-body potentials have been constructed for ten hcp metals: Be, Co, Hf, Mg, Re, Ru, Sc, Ti, Y and Zr. The potentials are parametrized using analytic functions and fitted to the cohesive energy, unrelaxed vacancy formation energy, five independent second-order elastic constants and two equilibrium conditions. Hence, each of the constructed potentials represents a stable hexagonal close-packed lattice with a particular non-ideal c/a ratio. In order to treat the metals with negative Cauchy pressure, a modified term has been added to the total energy. For all the metals considered, the hcp lattice is shown to be energetically most stable when compared with the fcc and bcc structure and the hcp lattice with ideal c/a. The activation energy for vacancy diffusion in these metals has been calculated. They agree well with experimental data available and those calculated by other authors for both monovacancy and divacancy mechanisms and the most possible diffusion paths are predicted. Stacking fault and surface energy have also been calculated and their values are lower than typical experimental data. Finally, the self-interstitial atom (SIA) formation energy and volume have been evaluated for eight possible sites. This calculation suggests that the basal split or crowdion is the most stable configuration for metals with a rather large deviation from the ideal c/a value and the non-basal dumbbell (C or S) is the most stable configuration for metals with c/a near ideal. The relationship between SIA formation energy and melting temperature roughly obeys a linear relation for most metals except Ru and Re. belytschko_review_2009 ArticleInAPeriodical 2009 Modelling Simul. Mater. Sci. Eng. Mater. Sci. Eng 17 17 http://iopscience.iop.org/0965-0393/17/4/043001 https://doi.org/10.1088/0965-0393/17/4/043001 43001-24 BelytschkoTed GracieRobert VenturaGiulio A review of extended/generalized finite element methods for material modeling The extended and generalized finite element methods are reviewed with an emphasis on their applications to problems in material science: (1) fracture, (2) dislocations, (3) grain boundaries and (4) phases interfaces. These methods facilitate the modeling of complicated geometries and the evolution of such geometries, particularly when combined with level set methods, as for example in the simulation growing cracks or moving phase interfaces. The state of the art for these problems is described along with the history of developments. berendsen_molecular_1984 ArticleInAPeriodical 1984 October The Journal of Chemical Physics 81 8 http://aip.scitation.org/doi/10.1063/1.448118 https://doi.org/10.1063/1.448118 3684-3690 BerendsenHJC PostmaJPM van GunsterenWF DiNolaA HaakJR Molecular dynamics with coupling to an external bath In molecular dynamics (MD) simulations the need often arises to maintain such parameters as temperature or pressure rather than energy and volume, or to impose gradients for studying transport properties in nonequilibrium MD. A method is described to realize coupling to an external bath with constant temperature or pressure with adjustable time constants for the coupling. The method is easily extendable to other variables and to gradients, and can be applied also to polyatomic molecules involving internal constraints. The influence of coupling time constants on dynamical variables is evaluated. A leap‐frog algorithm is presented for the general case involving constraints with coupling to both a constant temperature and a constant pressure bath. beyerlein_defect-interface_2015 ArticleInAPeriodical 2015 Progress in Materials Science 74 https://doi.org/10.1016/j.pmatsci.2015.02.001 125-210 BeyerleinIJ DemkowiczMJ MisraA UberuagaBP Defect-interface interactions Abstract Nanostructured materials contain an extremely high density of interfaces. The properties of these materials when exposed to extreme conditions of radiation dose, stress, deformation, or temperature are largely determined by defect-interface interactions. In this article, we review the present understanding of defect-interface interactions in single-phase and two-phase metal and oxide nanocomposites, emphasizing how interface structure affects interactions with point, line, and planar defects. We also review the crystallographic, chemical, and morphological stability of interfaces in different extreme environments: irradiation and mechanical deformation. Our current understanding of these topics prompts new questions that will maintain interfaces in crystalline solids at the frontier of materials research for years to come. beyerlein_emergence_2014 ArticleInAPeriodical 2014 ConferenceProceedings of the National Academy of Sciences 111 12 http://www.pnas.org/cgi/doi/10.1073/pnas.1319436111 https://doi.org/10.1073/pnas.1319436111 4386-4390 BeyerleinIJ MayeurJR ZhengS MaraNA WangJ MisraA Emergence of stable interfaces under extreme plastic deformation Atomically ordered bimetal interfaces typically develop in near-equilibrium epitaxial growth (bottom-up processing) of nanolayered composite films and have been considered responsible for a number of intriguing material properties. Here, we discover that interfaces of such atomic level order can also emerge ubiquitously in large-scale layered nanocomposites fabricated by extreme strain (top down) processing. This is a counterintuitive result, which we propose occurs because extreme plastic straining creates new interfaces separated by single crystal layers of nanometer thickness. On this basis, with atomic-scale modeling and crystal plasticity theory, we prove that the preferred bimetal interface arising from extreme strains corresponds to a unique stable state, which can be predicted by two controlling stability conditions. As another testament to its stability, we provide experimental evidence showing that this interface maintains its integrity in further straining (strains \textbackslashtextgreater 12), elevated temperatures (\textbackslashtextgreater 0.45 Tm of a constituent), and irradiation (light ion). These results open a new frontier in the fabrication of stable nanomaterials with severe plastic deformation techniques. bhattacharyya_transmission_2009 ArticleInAPeriodical 2009 March Journal of Materials Research 24 03 http://www.journals.cambridge.org/abstract_S0884291400032052 https://doi.org/10.1557/jmr.2009.0147 1291-1302 BhattacharyyaD MaraNA DickersonP HoaglandRG MisraA Transmission electron microscopy study of the deformation behavior of Cu/Nb and Cu/Ni nanoscale multilayers during nanoindentation \textlessdiv class=”abstract” data-abstract-type=”normal”\textgreater\textlessp\textgreaterNanoscale metallic multilayers, comprising two sets of materials—Cu/Nb and Cu/Ni—were deposited in two different layer thicknesses—nominally 20 and 5 nm. These multilayer samples were indented, and the microstructural changes under the indent tips were studied by extracting samples from underneath the indents using the focused ion beam (FIB) technique and by examining them under a transmission electron microscope (TEM). The deformation behavior underneath the indents, manifested in the bending of layers, reduction in layer thickness, shear band formation, dislocation crossing of interfaces, and orientation change of grains, has been characterized and interpreted in terms of the known deformation mechanisms of nanoscale multilayers.\textless/p\textgreater\textless/div\textgreater Bitzek_2004 ArticleInAPeriodical Elsevier BV 2004 dec Materials Science and Engineering: A 387-389 https://doi.org/10.1016%2Fj.msea.2004.01.092 11-15 BitzekErik GumbschPeter Atomistic study of drag, surface and inertial effects on edge dislocations in face-centered cubic metals Bitzek_2006 ArticleInAPeriodical American Physical Society (APS) 2006 oct Physical Review Letters 97 17 https://doi.org/10.1103%2Fphysrevlett.97.170201 BitzekErik KoskinenPekka GählerFranz MoselerMichael GumbschPeter Structural Relaxation Made Simple bitzek_atomistic_2008 ArticleInAPeriodical 2008 Journal of Solid Mechanics and Materials Engineering 2 10 http://joi.jlc.jst.go.jp/JST.JSTAGE/jmmp/2.1348?from=CrossRef https://doi.org/10.1299/jmmp.2.1348 1348-1359 BITZEKErik GUMBSCHPeter Atomistic Simulations of Dislocation - Crack Interaction bitzek_atomistic_2015 ArticleInAPeriodical 2015 International Journal of Fracture 191 1-2 https://doi.org/10.1007/s10704-015-9988-2 13-30 BitzekErik KermodeJamesR GumbschPeter Atomistic aspects of fracture Any fracture process ultimately involves the rupture of atomic bonds. Processes at the atomic scale therefore critically influence the toughness and overall fracture behavior of materials. Atomistic simulation methods including large-scale molecular dynamics simulations with classical potentials, density functional theory calculations and advanced concurrent multiscale methods have led to new insights e.g. on the role of bond trapping, dynamic effects, crack-microstructure interactions and chemical aspects on the fracture toughness and crack propagation patterns in metals and ceramics. This review focuses on atomistic aspects of fracture in crystalline materials where significant advances have been achieved over the last ten years and provides an outlook on future perspectives for atomistic modelling of fracture. bitzek_mechanisms_2013 ArticleInAPeriodical 2013 Acta Materialia 61 4 https://doi.org/10.1016/j.actamat.2012.11.016 1394-1403 BitzekErik GumbschPeter Mechanisms of dislocation multiplication at crack tips Whether a stressed material fractures by brittle cleavage or ductile rupture is determined by its ability to convert elastic strain energy to plastic deformation through the generation and motion of dislocations. Although it is known that pre-existing dislocations play a crucial role in crack tip plasticity, the involved mechanisms are unclear. Here it is demonstrated by atomistic simulations that individual pre-existing dislocations may lead to the generation of large numbers of dislocations at the crack tip. The newly generated dislocations are usually of different types. The processes involved are fundamentally different for stationary cracks and propagating cracks. Whereas local crack front reorientation plays an important role in propagating cracks, the multiplication mechanism at stationary cracks is connected with cross-slip in the highly inhomogeneous stress field of the crack. Analysis of the forces acting on the dislocations allows to determine which dislocations multiply and the slip systems they activate. These results provide the necessary physical link between pre-existing dislocations and the generation of dislocations at crack tips. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. bitzek_structural_2006 ArticleInAPeriodical 2006 October Physical Review Letters 97 17 https://link.aps.org/doi/10.1103/PhysRevLett.97.170201 https://doi.org/10.1103/PhysRevLett.97.170201 170201 BitzekErik KoskinenPekka GählerFranz MoselerMichael GumbschPeter Structural Relaxation Made Simple bollmann_basic_1972 ArticleInAPeriodical 1972 Surface Science 31 C https://doi.org/10.1016/0039-6028(72)90250-6 1-11 BollmannW The basic concepts of the 0-lattice theory The 0-lattice theory is a geometrical approach to the structure of crystalline interfaces. The quantitative evaluation of the theory and its application to specific problems needs a certain amount of linear algebra. In this paper the concepts of the theory are discussed as far as possible in non-mathematical terms in order to promote general understanding of the basis and of the field of application of the theory. © 1972. britton_mechanistic_2015 ArticleInAPeriodical 2015 Proc. R. Soc. A 471 https://doi.org/10.1098/rspa.2014.0881 20140881 BrittonTB DunneFPE WilkinsonAJ On the mechanistic basis of deformation at the microscale in hexagonal close-packed metals On the mechanistic basis of deformation at the microscale in hexagonal close-packed metals budarapu_adaptive_2014 ArticleInAPeriodical 2014 Computational Mechanics 53 6 https://doi.org/10.1007/s00466-013-0952-6 1129-1148 BudarapuPattabhiR GracieRobert BordasStéphaneP.A. RabczukTimon An adaptive multiscale method for quasi-static crack growth This paper proposes an adaptive atomistic- continuum numerical method for quasi-static crack growth. The phantom node method is used to model the crack in the continuum region and a molecular statics model is used near the crack tip. To ensure self-consistency in the bulk, a virtual atom cluster is used to model the material of the coarse scale. The coupling between the coarse scale and fine scale is realized through ghost atoms. The ghost atom positions are interpolated from the coarse scale solution and enforced as boundary conditions on the fine scale. The fine scale region is adaptively enlarged as the crack propagates and the region behind the crack tip is adaptively coarsened. An energy criterion is used to detect the crack tip location. The triangular lattice in the fine scale region corresponds to the lattice structure of the (111) plane of an FCC crystal. The Lennard-Jones potential is used to model the atom-atom interactions. The method is implemented in two dimensions. The results are compared to pure atomistic simulations; they show excellent agreement. © 2013 Springer-Verlag Berlin Heidelberg. Bussi_2007 ArticleInAPeriodical AIP Publishing 2007 jan The Journal of Chemical Physics 126 1 https://doi.org/10.1063%2F1.2408420 014101 BussiGiovanni DonadioDavide ParrinelloMichele Canonical sampling through velocity rescaling caputo_evaluation_2013 ArticleInAPeriodical 2013 Engineering Fracture Mechanics 103 https://doi.org/10.1016/j.engfracmech.2012.09.030 162-173 CaputoFrancesco LamannaGiuseppe SopranoAlessandro On the evaluation of the plastic zone size at the crack tip The extension of the plastic zone which takes place at the tip of a crack strictly depends on many variables, such as the yield stress of the material, the loading conditions, the crack size and the thickness of the cracked component; an exact analytical solution, such as to evaluate the plastic zone size (PZS) while taking into account all those parameters, is not yet available, mainly because of the difficulties in computing the stress-strain field ahead of the tip of a growing crack.In the present paper, by using a parametric 3D finite element model, the authors show the results obtained from extensive numerical analyses which have been developed first of all with the aim to assess the limits of linear elastic fracture mechanics (LEFM) parameters, when used to describe the stress state at the crack tip of both physically short cracks and long cracks in presence of high loads. Subsequently, the combined influence of the loading conditions, the yield stress of the material, the crack size and the thickness of the component on PZS at the crack tip has been investigated. At the end, an analytical relationship, which links, in a closed form, PZS to all these parameters and which is able to determine the PZS at crack tip of both physically short cracks and long cracks has been proposed. © 2012 Elsevier Ltd. carlton_what_2007 ArticleInAPeriodical 2007 Acta Materialia 55 11 https://doi.org/10.1016/j.actamat.2007.02.021 3749-3756 CarltonCE FerreiraPJ What is behind the inverse Hall-Petch effect in nanocrystalline materials? An inverse Hall-Petch effect has been observed for nanocrystalline materials by a large number of researchers. This effect implies that nanocrystalline materials get softer as grain size is reduced below a critical value. Postulated explanations for this behavior include dislocation-based models, diffusion-based models, grain-boundary-shearing models and two-phase-based models. In this paper, we report an explanation for the inverse Hall-Petch effect based on the statistical absorption of dislocations by grain boundaries, showing that the yield strength is dependent on strain rate and temperature and deviates from the Hall-Petch relationship below a critical grain size. © 2007 Acta Materialia Inc. Carpenter_2012 ArticleInAPeriodical Elsevier BV 2012 apr Acta Materialia 60 6-7 https://doi.org/10.1016%2Fj.actamat.2012.01.029 2625-2636 CarpenterJohnS MisraAmit AndersonPeterM Achieving maximum hardness in semi-coherent multilayer thin films with unequal layer thickness Chen_2018a ArticleInAPeriodical Elsevier BV 2018 mar Computational Materials Science 144 https://doi.org/10.1016%2Fj.commatsci.2017.11.051 1-10 ChenHao XuShuozhi LiWeixuan JiRigelesaiyin PhanThanh XiongLiming A spatial decomposition parallel algorithm for a concurrent atomistic-continuum simulator and its preliminary applications Chen_2018 ArticleInAPeriodical Elsevier BV 2018 jan Acta Materialia 143 https://doi.org/10.1016%2Fj.actamat.2017.10.012 107-120 ChenXY KongXF MisraA LegutD YaoBN GermannTC ZhangRF Effect of dynamic evolution of misfit dislocation pattern on dislocation nucleation and shear sliding at semi-coherent bimetal interfaces Chen_2019 ArticleInAPeriodical AIP Publishing 2019 sep Journal of Applied Physics 126 10 https://doi.org/10.1063%2F1.5099653 101101 ChenYouping ShabanovSergei McDowellDavidL Concurrent atomistic-continuum modeling of crystalline materials Chen_2020 ArticleInAPeriodical Elsevier BV 2020 aug Acta Materialia https://doi.org/10.1016%2Fj.actamat.2020.08.019 ChenY LiN HoaglandRG LiuX.-Y. BaldwinJK BeyerleinIJ ChengJY MaraNA Effects of three-dimensional Cu/Nb interfaces on strengthening and shear banding in nanoscale metallic multilayers chen_atomistic_2005 ArticleInAPeriodical 2005 Philosophical Magazine 85 33-35 https://doi.org/10.1080/14786430500362595 4095-4126 ChenY LeeJ Atomistic formulation of a multiscale field theory for nano/micro solids This paper aims to formulate a field theory for the solution of classical N-body problem. In this paper, multi-length and time scale material behaviour is addressed from the viewpoint of lattice dynamics. A multiscale field theory that can work as an alternative to molecular dynamics simulation in studying statistical and finite temperature properties of materials is proposed. Atomistic definitions and the corresponding field representations of fundamental physical quantities are obtained. Time evolutions of conserved physical quantities are derived in terms of atomic variables and are expressed in terms of field quantities. The mathematical representation of conservation laws for a multiscale field theory is formulated. cheng_misfit_2007 ArticleInAPeriodical 2007 February Thin Solid Films 515 7-8 https://www.sciencedirect.com/science/article/pii/S0040609006011011 https://doi.org/10.1016/J.TSF.2006.10.001 3698-3703 ChengDong YanZhiJun YanLi Misfit dislocation network in Cu/Ni multilayers and its behaviors during scratching The structure and distribution of misfit dislocations at Cu–Ni interfaces and their effects on the tribological behavior of a Ni film are investigated with 3D Molecular Dynamic Simulations. The structure of misfit dislocation network at a Cu–Ni interface differs according to different crystallographic orientations of the film relative to the substrate: a triangle and square type of misfit dislocation network are observed at (111)Cu\textbar\textbar(111)Ni and (001)Cu\textbar\textbar(001)Ni interfaces respectively. They play an important role in the strengthening of Cu/Ni multilayers. During the scratching of a single asperity contact on the Ni film, the misfit dislocation network becomes a significant barrier to the glide dislocations. The plot of friction force vs. normal load when scratching on the Ni film exhibits a horizontal stage, representing the decreasing of the frictional coefficient due to the existence of the misfit dislocations network. chetty_stacking_1997 ArticleInAPeriodical 1997 Physical Review B - Condensed Matter and Materials Physics 56 17 https://doi.org/10.1103/PhysRevB.56.10844 10844-10851 ChettyN WeinertM Stacking faults in magnesium The energetics of various low-energy intrinsic, extrinsic, and twinlike stacking fault configurations in hexagonal-close-packed magnesium are determined from first-principles calculations. To zeroth-order, the ordering of the energies can be understood in terms of the number of fcc-like planes in the sequence of close-packed planes. However, such a simple model fails to quantitatively reproduce the calculated energies of the faults. We propose a model based on a local bond orientation scheme which reproduces the calculated results and is able to accurately predict the energies of arbitrary stacking sequences. This model has only two independent parameters, the energy of the intrinsic I1 stacking fault and the energy difference between hcp and fcc Mg. Both energy and entropy considerations suggest that isolated I1 stacking faults should predominate. cheung_computer_2008 Book 2008 179 1-3 https://doi.org/10.1016/j.cpc.2008.01.029 CheungDavidL AntonLucian AllenMichaelP MastersAndrewJ Computer simulation of liquids and liquid crystals Monte Carlo simulations of a variety of hard-particle liquids and liquid mixtures have been conducted in the isotropic liquid region of the phase diagram. The position- and orientation-dependent pairwise structure is computed and the results are compared with integral equation theories, allowing us to examine the closure relations, and evaluate their accuracy, in a direct fashion. The equation of state and stability properties of these phases relative to the nematic liquid crystal phase, are also discussed. © 2008 Elsevier B.V. All rights reserved. cho_toward_2015 ArticleInAPeriodical 2015 Advanced Modeling and Simulation in Engineering Sciences 2 12 https://doi.org/10.1186/s40323-015-0028-6 ChoJaehyun JungeTill MolinariJean-françois AnciauxGuillaume Toward a 3D coupled atomistic and discrete dislocation dynamics simulation : dislocation core structures and Peierls stresses with several character angles in FCC aluminum clemens_structure_1999 ArticleInAPeriodical 1999 February MRS Bulletin 24 02 http://www.journals.cambridge.org/abstract_S0883769400051502 https://doi.org/10.1557/S0883769400051502 20-26 ClemensBM KungH BarnettSA Structure and Strength of Multilayers \textbackslashtextlessp\textbackslashtextgreater Nanometer-scale multilayer materials exhibit a wealth of interesting structural and mechanical property behaviors. Physical-vapor-deposition technology allows almost unlimited freedom to choose among elements, alloys, and Compounds as layering constituents and to design and produce materials with compositional and structural periodicities approaching the atomic Scale. These materials have tremendous interface area density, approaching 10 \textbackslashtextlesssup\textbackslashtextgreater6\textbackslashtextless/sup\textbackslashtextgreater mm/mm \textbackslashtextlesssup\textbackslashtextgreater3\textbackslashtextless/sup\textbackslashtextgreater , so that a Square centimeter area of a one-micron-thick multilayer film with a bilayer period of 2 nm has an interface area of roughly 1,000 cm \textbackslashtextlesssup\textbackslashtextgreater2\textbackslashtextless/sup\textbackslashtextgreater . Hence interfacial effects can dominate multilayer structure and properties leading to unusually large strains and frequently stabilization of metastable structures. The atomic-scale layering of different materials also leads to very high hardnesses and good wear resistance. These materials are a test-bed for examination of the fundamental aspects of phase stability and for exploring mechanical strengthening mechanisms. They are also becoming increasingly interesting for applications such as hard coatings, x-ray optical elements, in microelectromechanical Systems (MEMS), and in magnetic recording media and heads. \textbackslashtextless/p\textbackslashtextgreater Couret_1993 ArticleInAPeriodical EDP Sciences 1993 Microscopy Microanalysis Microstructures 4 2-3 https://doi.org/10.1051%2Fmmm%3A0199300402-3015300 153-170 CouretA CrestouJ FarencS MolenatG ClementN CoujouA CaillardD In situ deformation in T.E.M.: recent developments cui_investigation_2017 Book 2017 53 9 http://link.springer.com/10.1007/978-3-642-35133-4 https://doi.org/10.1007/978-3-642-35133-4 CuiYinan The Investigation of Plastic Behavior by Discrete Dislocation Dynamics for Single Crystal Pillar at Submicron Scale Die vorliegende Arbeit beschaeftigt sich mit der kontrollierten Strukturierung von Oberflaechen mit Kolloid-Monolagen. Verschiedene Aspekte solcher Strukturierungen werden vorgestellt, die sich in zwei Themengebiete untergliedern lassen. Zum einen werden Methoden zur Abscheidung von solchen Kolloidmonolagen auf festen Substraten vorgestellt. Zum anderen werden mehrere Ansaetze zu lithographischen Strukturierungsverfahren basierend auf Kolloidmonolagen vorgestellt. Im ersten Themenblock werden drei Ansaetze zur zweidimensionalen Kristallisation von Kolloiden entwickelt, die sich in der Komplexitaet und Struktur der Monolagen unterscheiden. Ein einfacher Ansatz zur Kristallisation von dichtgepackten, hochgeordneten Monolagen basierend auf einer spontanen Anordnung von Kolloiden an der Luft/Wasser Grenzflaeche wird beschrieben. Der ”Monolayer to go” genannte Ansatz ist eine der einfachsten Arten, homogene Monolagen ueber grosse Flaechen und mit hoher Ordnung zu kristallisieren und kann ohne experimentellen Aufwand oder besondere Hilfsmittel einfach im Labor durchgefuehrt werden. Eine Plasmabehandlung solcher Monolagen fuehrt direkt zu nicht-dicht gepackten Monolagen, die im zweiten Teil zur Erzeugung komplexer metallischer Nanopartikel verwendet werden. Schliesslich wird eine Methode entwickelt, um gezielt und reproduzierbar symmetrische, binaere Monolagen herzustellen. Um die Stoechioemetrie der binaeren Kristalle korrekt einzustellen, muss der Bruchteil der Kolloide an der Grenzflaeche fuer alle verschiedenen verwendeten Kolloiddispersionen einzeln aus den Isothermen eines Langmuir-Trogs bestimmt werden. Im zweiten Teil der Arbeit werden lithographische Verfahren basierend auf Kolloid-Monolagen beschrieben. Drei Ansaetze werden verfolgt. Aus homogenen, dicht-gepackten Monolagen werden eingebettete Dreicks-Nanostrukturen mittels eines template-stripping Prozesses hergestellt. Diese koennen als extrem robuste, wiederverwendbare Sensoren und als Substrate zur Strukturierung von Lipid-Doppelschichtmembranen mit Nanometer-Dimensionen verwendet werden. Desweiteren werden zwei Prozesse beschrieben, um aus nicht-dicht gepackten Monolagen dimere Hoernchenstrukturen herzustellen. Solche komplexen metallischen Nanostrukturen zeichnen sich durch interessante optische Eigenschaften aus. Durch den geringen Abstand der zwei Hoernchen in den dimeren Strukturen laesst sich eine Plasmonenhybridisierung beobachten. Letztlich werden Metallkomplrx-haltige Monolagen in einem nicht-konventionellen Verfahren verwendet, um metallische Nanostrukturen durch kontrolliertes Verbrennen der organischen Bestandteile der Kolloide zu erhalten. Damadam_2017 ArticleInAPeriodical Springer Science and Business Media LLC 2017 oct Journal of Materials Science 53 8 https://doi.org/10.1007%2Fs10853-017-1704-3 5604-5617 DamadamMohsen ShaoShuai AyoubGeorges ZbibHusseinM Recent advances in modeling of interfaces and mechanical behavior of multilayer metallic/ceramic composites Daw_1984 ArticleInAPeriodical American Physical Society (APS) 1984 jun Physical Review B 29 12 https://doi.org/10.1103%2Fphysrevb.29.6443 6443-6453 DawMurrayS BaskesMI Embedded-atom method: Derivation and application to impurities, surfaces, and other defects in metals daw_embedded-atom_1984 ArticleInAPeriodical 1984 Physical Review B 29 12 https://doi.org/10.1103/PhysRevB.29.6443 6443-6453 DawMurrayS BaskesMI Embedded-atom method: Derivation and application to impurities, surfaces, and other defects in metals We develop the embedded-atom method Phys. Rev. Lett. 50 1285 (1983), based on density-functional theory, as a new means of calculating ground-state properties of realistic metal systems. We derive an expression for the total energy of a metal using the embedding energy from which we obtain several ground-state properties, such as the lattice constant, elastic constants, sublimation energy, and vacancy-formation energy. We obtain the embedding energy and accompanying pair potentials semiempirically for Ni and Pd, and use these to treat several problems: surface energy and relaxation of the (100), (110), and (111) faces; properties of H in bulk metal (H migration, binding of H to vacancies, and lattice expansion in the hydride phase); binding site and adsorption energy of hydrogen on (100), (110), and (111) surfaces; and lastly, fracture of Ni and the effects of hydrogen on the fracture. We emphasize problems with hydrogen and with surfaces because none of these can be treated with pair potentials. The agreement with experiment, the applicability to practical problems, and the simplicity of the technique make it an effective tool for atomistic studies of defects in metals. dehm_overview_2018 ArticleInAPeriodical 2018 Acta Materialia 142 https://doi.org/10.1016/j.actamat.2017.06.019 248-282 DehmG JayaBN RaghavanR KirchlechnerC Overview on micro- and nanomechanical testing: New insights in interface plasticity and fracture at small length scales Micro- and nanomechanical testing has seen a rapid development over the last decade with miniaturized test rigs and MEMS-based devices providing access to the mechanical properties and performance of materials from the micrometer down to the tenths of nanometer length scale. In this overview, we summarize firstly the different testing concepts with excursions into recent imaging and diffraction developments, which turn micro- and nanomechanical testing into “quantitative mechanical microscopy” by resolving the underlying material physics and simultaneously providing mechanical properties. A special focus is laid on the pitfalls of micro-compression testing with its stringent boundary conditions often hampering reliable experiments. Additionally, the challenges of instrumented micro- and nanomechanical testing at elevated temperature are summarized. From the wide variety of research topics employing micro- and nanomechanical testing of materials we focus here on miniaturized samples and test rigs and provide three examples to elucidate the state-of-the-art of the field: (i) probing the “strength” of individual grain boundaries in metals, (ii) temperature dependent deformation mechanisms in metallic nanolayered and -alloyed structures, and (iii) the prospects and challenges of fracture studies employing micro- and nanomechanical testing of brittle and ductile monolithic materials, and materials containing interfaces. Proven concepts and new endeavors are reported for the topics discussed in this overview. Demkowicz_2011 ArticleInAPeriodical Elsevier BV 2011 dec Acta Materialia 59 20 https://doi.org/10.1016%2Fj.actamat.2011.09.004 7744-7756 DemkowiczMJ ThillyL Structure, shear resistance and interaction with point defects of interfaces in Cu–Nb nanocomposites synthesized by severe plastic deformation deng_coarse-grained_2013 ArticleInAPeriodical 2013 International Journal for Multiscale Computational Engineering 11 3 https://doi.org/10.1615/IntJMultCompEng.2013005442 227-237 DengQian ChenYouping A Coarse-grained atomistic method for 3D dynamic fracture simulation In this work, a new coarse-grained (CG) method is presented. The new method combines an atomistic formulation of balance equations and a modified finite element method. Through three numerical examples, we demonstrate that the new method is able to predict the dynamic fracture behavior of crystalline materials. First, the stress wave propagation is simulated through the CG method and the stress response is found to be identical with that of the corresponding atomic-level molecular dynamics (MD) simulation. Then, three-dimensional dynamic crack propagation in a notched thin film under tension is simulated through both CG and MD simulations. Simulation results show that not only the crack propagation paths but also the local and average stresses calculated from CG simulations agree well with that from the corresponding MD simulations. Most importantly, although a large number of degrees of freedoms have been eliminated, the CG models capture the atomic-scale phenomenon such as the dislocation emission and migration accompanied with the crack propagation. In addition, through CG simulations of a plate under impact lading, the CG method is demonstrated to be able to simulate both stable crack propagation problems and the fragmentations of materials under high-strain-rate dynamic loading. Dewald_2006 ArticleInAPeriodical IOP Publishing 2006 apr Modelling and Simulation in Materials Science and Engineering 14 3 https://doi.org/10.1088%2F0965-0393%2F14%2F3%2F011 497-514 DewaldM CurtinWA Analysis and minimization of dislocation interactions with atomistic/continuum interfaces diard_evaluation_2005 ArticleInAPeriodical 2005 International Journal of Plasticity 21 4 https://doi.org/10.1016/j.ijplas.2004.05.017 691-722 DiardO LeclercqS RousselierG CailletaudG Evaluation of finite element based analysis of 3D multicrystalline aggregates plasticity Application to crystal plasticity model identification and the study of stress and strain fields near grain boundaries Plastic heterogeneities of hexagonal close-packed (HCP) materials are numerically investigated at the grain level. Intensive use of parallel Finite Elements computations enables us to study micro-plasticity of realistic 3D multicrystalline aggregates, including, macroscopic mechanical responses but also average responses in each grain and particularly local stress and strain fields. This paper focuses on three applications of this simulation method. The first part of this paper is devoted to a fine analysis of micro-plasticity of HCP materials. Intergranular but also intragranular stress and strain heterogeneities are described and micro-plasticity patterns are displayed throughout the 3D microstructures. A special attention is paid to the sensitivity of simulations with respect to the mesh discretization, the element interpolation and the geometrical representation of grain boundaries, in terms of macroscopic and local responses. Later, a simplified homogenization method is evaluated, regarding results of the first part. Afterwards, this method is applied with a zirconium alloy to identify a set of coefficients for a single crystal plasticity model. Finally, in order to provide critical information for intergranular damage phenomena (reported in literature for zirconium alloys), the third part provides a statistical analysis of over-stresses at grain boundaries. © 2004 Elsevier Ltd. All rights reserved. dikken:hal-01572509 Misc 2017 August https://hal.archives-ouvertes.fr/hal-01572509 DikkenRobbert-Jan Khajeh SalehaniMohsen Edge dislocation impingement on interfaces between dissimilar metals working paper or preprint ding_modeling_2015 ArticleInAPeriodical 2015 Advances in Materials Science and Engineering 2015 May https://doi.org/10.1155/2015/639519 DingZhigang LiShuang LiuWei ZhaoYonghao Modeling of Stacking Fault Energy in Hexagonal-Close-Packed Metals The deformation of metals is known to be largely affected by their stacking fault energies (SFEs). In the review, we examine the theoretical background of three normally used models, supercell model, Ising model, and bond orientation model, for the calculation of SFE of hexagonal-close-packed (hcp) metals and their alloys. To predict the nature of slip in nanocrystalline metals, we further review the generalized stacking fault (GSF) energy curves in hcp metals and alloys. We conclude by discussing the outstanding challenges in the modeling of SFE and GSF energy for studying the mechanical properties of metals. Dodaran_2019 ArticleInAPeriodical Elsevier BV 2019 jun Acta Materialia 171 https://doi.org/10.1016%2Fj.actamat.2019.04.016 92-107 DodaranM WangJ ChenY MengWJ ShaoS Energetic, structural and mechanical properties of terraced interfaces Dupraz_2019 ArticleInAPeriodical Elsevier BV 2019 aug Acta Materialia 174 https://doi.org/10.1016%2Fj.actamat.2019.05.025 16-28 DuprazMaxime RaoSatishI SwygenhovenHelenaVan Large scale 3-dimensional atomistic simulations of screw dislocations interacting with coherent twin boundaries in Al, Cu and Ni under uniaxial and multiaxial loading conditions Erel_2017a ArticleInAPeriodical Informa UK Limited 2017 aug Philosophical Magazine 97 32 https://doi.org/10.1080%2F14786435.2017.1361555 2947-2970 ErelC PoG GhoniemN Dependence of hardening and saturation stress in persistent slip bands on strain amplitude during cyclic fatigue loading Erel_2017 ArticleInAPeriodical Elsevier BV 2017 dec Computational Materials Science 140 https://doi.org/10.1016%2Fj.commatsci.2017.07.043 32-46 ErelCan PoGiacomo CrosbyTamer GhoniemNasr Generation and interaction mechanisms of prismatic dislocation loops in FCC metals eringen1999microcontinuum Book New York, NY Springer New York 1999 EringenA Microcontinuum Field Theories : I. Foundations and Solids eslami_study_2013 ArticleInAPeriodical 2013 August Materials Science and Technology 29 8 http://www.tandfonline.com/doi/full/10.1179/1743284713Y.0000000246 https://doi.org/10.1179/1743284713Y.0000000246 1000-1005 EslamiAH ZebarjadSMojtaba MoshksarMM Study on mechanical and magnetic properties of Cu/Ni multilayer composite fabricated by accumulative roll bonding process AbstractAccumulative roll bonding (ARB) has been used as a severe plastic deformation process for the production of high strength materials. In the current research, multilayered copper/nickel composites were produced by the ARB process using nickel and copper strips. Tensile and magnetic behaviours of produced composites were investigated by universal tensile machine and magnetic device detector (vibrating sample magnetometers) respectively. It was observed that as passes of ARB proceeded, nickel layers were necked and fractured gradually. After five roll bonding passes, a multilayer copper/nickel composite including homogeneously distributed fragmented nickel layers in the copper matrix was achieved. Magnetic and mechanical properties of these composites were studied within different stages of the ARB process. With increasing strain during ARB passes, strength, microhardness and elongation of these composites increased. Enhancement of the strength is higher than the tensile strength of copper/copper mul... Evans_1985 ArticleInAPeriodical AIP Publishing 1985 oct The Journal of Chemical Physics 83 8 https://doi.org/10.1063%2F1.449071 4069-4074 EvansDJ HolianBL The Nose–Hoover thermostat Faken_1994 ArticleInAPeriodical Elsevier BV 1994 mar Computational Materials Science 2 2 https://doi.org/10.1016%2F0927-0256%2894%2990109-0 279-286 FakenDaniel JónssonHannes Systematic analysis of local atomic structure combined with 3D computer graphics fan_simulation_2017 ArticleInAPeriodical 2017 Engineering Fracture Mechanics 170 https://doi.org/10.1016/j.engfracmech.2016.11.035 87-106 FanJinghong StewartRoss XuTaolong Simulation accuracy of crack-tip parameters with extended GP methods The success in using the GP, short for the generalized particle dynamics method (Fan, 2009), with the cohesive zone method (CZM) to bridge crack propagation at the atomistic and mesoscopic scale (Xu et al., 2016) brings more attention to its central issue: simulation accuracy of crack-tip parameters. This issue is addressed in this work by an extension of the GP method in which finite element (FE) nodes are connected with the outermost particles, thus it can reduce artificial effects on the most interesting atomic regions to obtain accurate crack-tip parameters. The accuracy of the XGP, short for this extended GP method, is confirmed by comparisons of simulation results with classic analytical solutions of an edge-crack and a central cylindrical hole in a two dimensional plate. After developing a series of models from 60 nm to 5 μm, used in an asymptotic analysis for model size effect, it is applied to the atomistic crack-tip simulation of a Mode-I edge crack of iron under plane strain condition. Results show that there exists a problem-dependent critical model size, LCR, above which may not be necessary under a given error tolerance; below which the simulation result is inaccurate in underestimating crack-tip displacement, the range of the traction-separation (TS) curve and the critical energy release rate GIC and overestimating the initiation strain for the crack-tip BCC to FCC phase transformation. farkas_interatomic_1994 ArticleInAPeriodical 1994 Modelling and Simulation in Materials Science and Engineering 2 975 FarkasDiana Interatomic potentials for Ti-Al with and without angular forces farkas_modelling_1994 ArticleInAPeriodical 1994 FarkasDiana JonesChris Modelling and Simulation in Materials Science and Engineering Related content Interatomic potentials for Ti-Al with and without angular forces Interatomic potentials for Ti-AI with and without angular forces feyel_multilevel_2003 ArticleInAPeriodical 2003 Computer Methods in Applied Mechanics and Engineering 192 28-30 https://doi.org/10.1016/S0045-7825(03)00348-7 3233-3244 FeyelFr??d??ric A multilevel finite element method (FE2) to describe the response of highly non-linear structures using generalized continua A general method called FE2 has been introduced which consists in describing the behavior of heterogeneous structures using a multiscale finite element model. Instead of trying to build differential systems to establish a stress-strain relation at the macroscale, a finite element computation of the representative volume element is carried out simultaneously. Doing so does not require any constitutive equations to be written at the macroscopic scale: all non-linearities come directly from the microscale. In this paper, we describe how this method can be used in the context of generalized continua. For such continua, constitutive equations are very difficult to write, and a new set of material is difficult to fit to experimental data. The use of FE2 models bypasses this problem because no analytical equation is needed at the macroscale. An academic application is presented to show that generalized continua are necessary when the size of the heterogeneities increases, and that FE2 models behave well compared to a reference solution. ?? 2003 Elsevier B.V. All rights reserved. fleischer_cross_1959 ArticleInAPeriodical 1959 February Acta Metallurgica 7 2 https://www.sciencedirect.com/science/article/pii/0001616059901221 https://doi.org/10.1016/0001-6160(59)90122-1 134-135 FleischerRL Cross slip of extended dislocations Foecke_2003 ArticleInAPeriodical Springer Science and Business Media LLC 2003 International Journal of Fracture 119/120 4-2 https://doi.org/10.1023%2Fa%3A1024967510917 351-357 FoeckeT KramerDE In situ TEM observations of fracture in nanolaminated metallic thin films foiles_embedded-atom-method_1986 ArticleInAPeriodical 1986 Physical Review B 33 12 https://doi.org/10.1103/PhysRevB.33.7983 7983-7991 FoilesSM BaskesMI DawMS Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys A consistent set of embedding functions and pair interactions for use with the embedded-atom method [M.S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)] have been determined empirically to describe the fcc metals Cu, Ag, Au, Ni, Pd, and Pt as well as alloys containing these metals. The functions are determined empirically by fitting to the sublimation energy, equilibrium lattice constant, elastic constants, and vacancy-formation energies of the pure metals and the heats of solution of the binary alloys. The validity of the functions is tested by computing a wide range of properties: the formation volume and migration energy of vacancies, the formation energy, formation volume, and migration energy of divacancies and self-interstitials, the surface energy and geometries of the low-index surfaces of the pure metals, and the segregation energy of substitutional impurities to (100) surfaces. Franca_1989 ArticleInAPeriodical Elsevier BV 1989 Computers & Mathematics with Applications 18 5 https://doi.org/10.1016%2F0898-1221%2889%2990240-x 459-466 FrancaLP An algorithm to compute the square root of a 3 × 3 positive definite matrix fu_molecular_2016 ArticleInAPeriodical 2016 December Scientific Reports 6 1 http://www.nature.com/articles/srep35665 https://doi.org/10.1038/srep35665 35665 FuTao PengXianghe ChenXiang WengShayuan HuNing LiQibin WangZhongchang Molecular dynamics simulation of nanoindentation on Cu/Ni nanotwinned multilayer films using a spherical indenter Molecular dynamics simulation of nanoindentation on Cu/Ni nanotwinned multilayer films using a spherical indenter furuhara_computer_1991 ArticleInAPeriodical 1991 Acta Metallurgica Et Materialia 39 11 https://doi.org/10.1016/0956-7151(91)90103-8 2857-2872 FuruharaT AaronsonHI Computer modeling of partially coherent B.C.C.:H.C.P. boundaries A modeling study of partially coherent b.c.c.:h.c.p. coherent boundaries, using a computer-aided graphical technique, has been made for parallel pairs of low index planes in the presence of specified lattice orientation relationships. Three well-known lattice orientation relationships between the b.c.c. and h.c.p. phases, each of which was also slightly perturbed in various ways, were utilized. All of the planar interfaces thus formed which were based upon parallel pairs of low index planes can be described by two arrays of parallel misfit dislocations. The possibility of replacing one array of misfit dislocations with an array of structural ledges was then analyzed. In the presence of near-Burgers orientation relationships, the most probable structural ledges were found to have (1100)h.c.p.//(211)b.c.c. terraces with risers 2, 4 or 6 atomic layers high. This type of structural ledge has a Burgers vector of 1/12[111]b.c.c., which lies in the terrace plane, associated with its riser. Thus it can replace a set of a-type misfit dislocations; hence only a single set of c-type misfit dislocations is now necessary on the terrace of structural ledges. This types of structural ledge was also found to step down along the lattice invariant line in order to accommodate simultaneously the misfit normal to the terrace plane. Further, the possibility of structural ledges with (1101)h.c.p.//(110)b.c.c. terrace was also discerned in the presence of near-Potter orientation relationships. ?? 1991. furuhara_interphase_1990 ArticleInAPeriodical 1990 Metallurgical Transactions A 21 6 https://doi.org/10.1007/BF02672578 1627-1643 FuruharaT LeeHJ MenonESK AaronsonHI Interphase boundary structures associated with diffusional phase transformations in Ti-base alloys Interphase boundary structures generated during diffusional transformations in Ti-base alloys, especially the proeutectoid α and eutectoid reactions in a β-phase matrix, are reviewed. Partially coherent boundaries are shown to be present whether the orientation relationship between precipitate and matrix phases is rational or irrational. Usually, these structures include both misfit dislocations and growth ledges. However, grain boundary α allotriomorphs (GBA’s) do not appear to develop misfit dislocations at partially coherent boundaries. Evidently, these dislocations can be replaced by ledges which provide a strain vector in the plane of the interphase boundary. The bainite reaction in Ti-X alloys produces a mixture of eutectoid α and eutectoid intermetallic compound. Both eutectoid phases are partially coherent with the β matrix, and both grow by means of the ledge mechanism, though unlike pearlite the ledge systems of the two phases are structurally independent. Even after deformation and recrystallization, the boundaries between the eutectoid phases and the β matrix, as well as between these phases, are partially coherent. Titanium and zirconium hydrides have partially coherent interphase boundaries with respect to their β matrix. The recent observation of ledgewise growth of γ TiH with in situ high-resolution transmission electron microscopy (HRTEM) suggests that, repeated suggestions to the contrary, these hydrides do not grow by means of shear transport of Ti atoms at rates paced by hydrogen diffusion. © 1990 The Metallurgical of Society of AIME. gang_role_2017 ArticleInAPeriodical 2017 April Computational Materials Science 131 https://www.sciencedirect.com/science/article/pii/S0927025617300502 https://doi.org/10.1016/j.commatsci.2017.01.036 21-27 GangChen ChuanJieWang PengZhang The role of interface in uniaxial tensile process of nano-scale bilayer Cu/Ni Uniaxial tensile processes of nano-scale bilayer Cu/Ni with coherent interface (CI) and semi-coherent interface (SCI) are simulated by molecular dynamics (MD). The results show that in the deformation processes of two kind of Cu/Ni bilayer structures, dislocations nucleate from interface and the leading dislocations slipping cross the interface cause the bilayer structures getting into plastic deformation stage. The SCI leads to the strength and strain rate sensitivity (SRS) depending on the thickness of the nano-scale bilayer Cu/Ni, because of SCI hindering the dislocations slipping. However, due to the weak barriers of CI, the dislocation can cross the interface easily, which cause the independent of strength and SRS values on thickness. glaessgen_modeling_2010 ArticleInAPeriodical 2010 51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference 1-21 GlaessgenEH SaetherE HochhalterJD YamakovV Modeling Near-Crack-Tip Plasticity From Nano- to Micro-Scales Several efforts that are aimed at understanding the plastic deformation mechanisms related to crack propagation at the nano-, meso- and micro-length scales including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity are discussed. The paper focuses on discussion of newly developed methodologies and their application to understanding damage processes in aluminum and its alloys. Examination of plastic mechanisms as a function of increasing length scale illustrates increasingly complex phenomena governing plasticity. Introduction gracie_adaptive_2011 ArticleInAPeriodical 2011 April International Journal for Numerical Methods in Engineering 86 4-5 http://doi.wiley.com/10.1002/nme.3112 https://doi.org/10.1002/nme.3112 575-597 GracieRobert BelytschkoTed An adaptive concurrent multiscale method for the dynamic simulation of dislocations gracie_concurrently_2009 ArticleInAPeriodical 2009 April International Journal for Numerical Methods in Engineering 78 3 http://doi.wiley.com/10.1002/nme.2488 https://doi.org/10.1002/nme.2488 354-378 GracieRobert BelytschkoTed Concurrently coupled atomistic and XFEM models for dislocations and cracks gracie_new_2008 ArticleInAPeriodical 2008 Journal of the Mechanics and Physics of Solids 56 1 https://doi.org/10.1016/j.jmps.2007.07.010 200-214 GracieRobert OswaldJay BelytschkoTed On a new extended finite element method for dislocations: Core enrichment and nonlinear formulation A recently developed finite element method for the modeling of dislocations is improved by adding enrichments in the neighborhood of the dislocation core. In this method, the dislocation is modeled by a line or surface of discontinuity in two or three dimensions. The method is applicable to nonlinear and anisotropic materials, large deformations, and complicated geometries. Two separate enrichments are considered: a discontinuous jump enrichment and a singular enrichment based on the closed-form, infinite-domain solutions for the dislocation core. Several examples are presented for dislocations constrained in layered materials in 2D and 3D to illustrate the applicability of the method to interface problems. ?? 2007 Elsevier Ltd. All rights reserved. grujicic_molecular_1996 ArticleInAPeriodical 1996 Materials Science and Engineering A 219 109-125 GrujicicM DangP A molecular dynamics study of transformation toughening in the gamma TiAl/beta Ti-V system Gu_nol__2020 ArticleInAPeriodical Elsevier BV 2020 apr Computational Materials Science 175 https://doi.org/10.1016%2Fj.commatsci.2020.109584 109584 GuénoléJulien NöhringWolframG VaidAviral HoulléFrédéric XieZhuocheng PrakashAruna BitzekErik Assessment and optimization of the fast inertial relaxation engine (fire) for energy minimization in atomistic simulations and its implementation in lammps hadian_atomistic_2016 ArticleInAPeriodical 2016 Physical Review B 94 16 https://doi.org/10.1103/PhysRevB.94.165413 1-10 HadianR GrabowskiB RaceCP NeugebauerJ Atomistic migration mechanisms of atomically flat, stepped, and kinked grain boundaries © 2016 American Physical Society.We studied the migration behavior of mixed tilt and twist grain boundaries in the vicinity of a symmetric tilt (111) Σ7 grain boundary in aluminum. We show that these grain boundaries fall into two main categories of stepped and kinked grain boundaries around the atomically flat symmetric tilt boundary. Using these structures together with size converged molecular dynamics simulations and investigating snapshots of the boundaries during migration, we obtain an intuitive and quantitative description of the kinetic and atomistic mechanisms of the migration of general mixed grain boundaries. This description is closely related to well-known concepts in surface growth such as step and kink-flow mechanisms and allows us to derive analytical kinetic models that explain the dependence of the migration barrier on the driving force. Using this insight we are able to extract energy barrier data for the experimentally relevant case of vanishing driving forces that are not accessible from direct molecular dynamics simulations and to classify arbitrary boundaries based on their mesoscopic structures. hanukah_exact_2014 ArticleInAPeriodical 2014 December https://arxiv.org/abs/1412.6538 HanukahEli Exact integration scheme for six-node wedge element mass matrix hardy_formulas_1982 ArticleInAPeriodical 1982 The Journal of chemical physics 76 1 http://scitation.aip.org/content/aip/journal/jcp/76/1/10.1063/1.442714 https://doi.org/http://dx.doi.org/10.1063/1.442714 622-628 HardyRobertJ Formulas for determining local properties in molecular dynamics simulations: Shock waves hasnaoui_interaction_2004 ArticleInAPeriodical 2004 Acta Materialia 52 8 https://doi.org/10.1016/j.actamat.2004.01.018 2251-2258 HasnaouiA DerletPM Van SwygenhovenH Interaction between dislocations and grain boundaries under an indenter - A molecular dynamics simulation Large-scale molecular dynamics simulations of nanocrystalline Au are used to investigate the interaction between dislocations emitted under an indenter and the nearby grain boundary network. It is shown that for cases where the indenter size is smaller than the grain size, grain boundaries not only act as a sink for dislocations, but that depending on their local structure and stress distribution, they can also reflect or emit dislocations. The emission and absorption process is accompanied by local atomic activity involving atomic shuffling and free volume migration within the grain boundary region. © 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Hatano_2006 ArticleInAPeriodical American Physical Society (APS) 2006 jul Physical Review B 74 2 https://doi.org/10.1103%2Fphysrevb.74.020102 HatanoTakahiro Dynamics of a dislocation bypassing an impenetrable precipitate: The Hirsch mechanism revisited Himanen_2020 ArticleInAPeriodical Elsevier BV 2020 feb Computer Physics Communications 247 https://doi.org/10.1016%2Fj.cpc.2019.106949 106949 HimanenLauri JägerMarcOJ MorookaEiakiV CanovaFilippoFederici RanawatYashasviS GaoDavidZ RinkePatrick FosterAdamS DScribe: Library of descriptors for machine learning in materials science Hiratani_2003 ArticleInAPeriodical Elsevier BV 2003 sep International Journal of Plasticity 19 9 https://doi.org/10.1016%2Fs0749-6419%2802%2900016-5 1271-1296 HirataniM ZbibHM KhaleelMA Modeling of thermally activated dislocation glide and plastic flow through local obstacles Hirel_2015 ArticleInAPeriodical Elsevier BV 2015 dec Computer Physics Communications 197 https://doi.org/10.1016%2Fj.cpc.2015.07.012 212-219 HirelPierre Atomsk: A tool for manipulating and converting atomic data files hirschmann_towards_2016 ConferenceProceedings IEEE 2016 December 2016 IEEE 23rd International Conference on High Performance Computing Workshops (HiPCW) http://ieeexplore.ieee.org/document/7837060/ https://doi.org/10.1109/HiPCW.2016.027 130-141 HirschmannSteffen PflugerDirk GlassColinW Towards Understanding Optimal Load-Balancing of Heterogeneous Short-Range Molecular Dynamics For heterogeneous dynamic short-range molecular dynamics simulations it is critical to employ suitable load-balancing methods to minimize the time to solution. However, designing and parametrizing the optimal load-balancing method is a complex task, depending on detailed properties of the simulation scenario.The main challenge in balancing the load of molecular dynamics simulations is the extreme difference in load density for scenarios with heterogeneous particle density, which can easily reach 4-6 orders of magnitude. Therefore, heterogeneity is deemed to be a relevant property and a suitable metric to reliably quantifying heterogeneity is formulated. This metric, which is based on binning particles and evaluating statistical moments, is then applied to example scenarios and correlated to the performance of five load balancing methodologies. Furthermore, how rapidly the load varies over time will determine how long the benefits of a specific partitioning are expected to last. We deem this to be another relevant property, the dynamics, and introduce corresponding metrics. The results indicate that these metric are useful to differentiate between scenarios and facilitate reasoning over the complex relationship between particle simulation scenarios and optimal load balancing methods. This work is a first step towards understanding this relationship, while introducing key concepts we regard as a crucial for this understanding. Hoagland_2004 ArticleInAPeriodical Elsevier BV 2004 mar Scripta Materialia 50 6 https://doi.org/10.1016%2Fj.scriptamat.2003.11.059 775-779 HoaglandRG KurtzRJ HenagerCH Slip resistance of interfaces and the strength of metallic multilayer composites hoagland_strengthening_2002 ArticleInAPeriodical 2002 March Philosophical Magazine A 82 4 http://www.tandfonline.com/doi/abs/10.1080/01418610208243194 https://doi.org/10.1080/01418610208243194 643-664 HoaglandRG MitchellTE HirthJP KungH On the strengthening effects of interfaces in multilayer fcc metallic composites Abstract The slip behaviour in coherent and semicoherent metallic bilayer composites is examined by atomic simulation in the Cu/Ni and Cu/Ag systems. The coherent interface in Cu/Ni, although energetically unfavourable relative to the semicoherent interface in thick layers, reveals several interesting phenomena. Linear elastic predictions of lattice strains to achieve coherency (removing the 2.7% lattice mismatch) are found not to satisfy equilibrium. The cause is nonlinearity in the elastic response. The application of stresses needed for glide dislocations to cross the interface or to escape from the interface exacerbates the nonlinearities in the elastic response of the system. Koehler forces, arising from elastic mismatch, are in some cases observed to have the wrong sign relative to linear elastic predictions. Core structures of misfit dislocations in semicoherent interfaces are observed to be quite different in the cube-on-cube oriented Cu/Ni and Cu/Ag systems with interfaces parallel to (010). In t... hoover_large-scale_1990 ArticleInAPeriodical 1990 November Physical Review A 42 10 https://link.aps.org/doi/10.1103/PhysRevA.42.5844 https://doi.org/10.1103/PhysRevA.42.5844 5844-5853 HooverWilliamG De GrootAnthonyJ HooverCarolG StowersIrvingF KawaiToshio HolianBradLee BokuTaisuke IharaSigeo BelakJ Large-scale elastic-plastic indentation simulations via nonequilibrium molecular dynamics huang_elastic_1970 ArticleInAPeriodical 1970 Journal of Applied Physics 41 13 https://doi.org/10.1063/1.1658641 5175-5179 HuangWen MuraT Elastic fields and energies of a circular edge disclination and a straight screw disclination Hunter_2017 ArticleInAPeriodical Springer Science and Business Media LLC 2017 dec Journal of Materials Science 53 8 https://doi.org/10.1007%2Fs10853-017-1844-5 5584-5603 HunterAbigail LeuBrandon BeyerleinIreneJ A review of slip transfer: applications of mesoscale techniques iacobellis_comparison_2013 ArticleInAPeriodical 2013 Journal of Applied Mechanics 80 5 http://appliedmechanics.asmedigitalcollection.asme.org/article.aspx?doi=10.1115/1.4023477 https://doi.org/10.1115/1.4023477 051003 IacobellisVincent BehdinanKamran Comparison of Concurrent Multiscale Methods in the Application of Fracture in Nickel This paper presents a study of fracture in nickel using multiscale modeling. A comparison of six concurrent multiscale methods was performed in their application to a common problem using a common framework in order to evaluate each method relative to each other. Each method was compared in both a quasi-static case of crack tip deformation as well as a dynamic case in the study of crack growth. Each method was compared to the fully atomistic model with similarities and differences between the methods noted and reasons for these provided. The results showed a distinct difference between direct and handshake coupling methods. In general, for the quasi-static case, the direct coupling methods took longer to run compared to the handshake coupling methods but had less error with respect to displacement and energy. In the dynamic case, the handshake methods took longer to run, but had reduced error most notably when wave dissipation at the atomistic/continuum region was an issue. Comparing each method under common conditions showed that many similarities exist between each method that may be hidden by their original formulation. The comparison also showed the dependency on the application as well as the simulation techniques used in determining the performance of each method. imrich_differences_2014 ArticleInAPeriodical 2014 July Acta Materialia 73 https://www.sciencedirect.com/science/article/pii/S1359645414002730 https://doi.org/10.1016/J.ACTAMAT.2014.04.022 240-250 ImrichPeterJ KirchlechnerChristoph MotzChristian DehmGerhard Differences in deformation behavior of bicrystalline Cu micropillars containing a twin boundary or a large-angle grain boundary Micrometer-sized compression pillars containing a grain boundary are investigated to better understand under which conditions grain boundaries have a strengthening effect. The compression experiments were performed on focused ion beam fabricated micrometer-sized bicrystalline Cu pillars including either a large-angle grain boundary (LAGB) or a coherent twin boundary (CTB) parallel to the compression axis and additionally on single-crystalline reference samples. Pillars containing a LAGB show increased strength, stronger hardening and smaller load drops compared to single crystals and exhibit a bent boundary and pillar shape. Samples with a CTB show no major difference in stress–strain data compared to the corresponding single-crystalline samples. This is due to the special orientation and symmetry of the twin boundary and is reflected in a characteristic pillar shape after deformation. The experimental findings can be related to the dislocation–boundary interactions at the different grain boundaries and are compared with three-dimensional discrete dislocation dynamics simulations. Jian_2020 ArticleInAPeriodical IOP Publishing 2020 apr Modelling and Simulation in Materials Science and Engineering 28 4 https://doi.org/10.1088%2F1361-651x%2Fab8358 045004 JianWu-Rong ZhangMin XuShuozhi BeyerleinIreneJ Atomistic simulations of dynamics of an edge dislocation and its interaction with a void in copper: a comparative study Kacher_2019 ArticleInAPeriodical Elsevier BV 2019 jun Current Opinion in Solid State and Materials Science 23 3 https://doi.org/10.1016%2Fj.cossms.2019.03.003 117-128 KacherJosh ZhuTing PierronOlivier SpearotDouglasE Integrating in situ TEM experiments and atomistic simulations for defect mechanics kanani_stacking_2016 ArticleInAPeriodical 2016 Acta Materialia 106 https://doi.org/10.1016/j.actamat.2015.11.047 208-218 KananiM HartmaierA JanischR Stacking fault based analysis of shear mechanisms at interfaces in lamellar TiAl alloys The interfaces in lamellar TiAl alloys have a strong influence on the strength and deformability of the microstructure. It is widely accepted that their number and spacing can be used to tune these properties. However, the results of molecular dynamics simulations of sliding at γ/γ interfaces in lamellar TiAl alloys presented here suggest that important factors, namely the sequence of different interface types as well as the orientation of in-plane directions with respect to the loading axis, have to be included into meso-scale models. Simulations of bicrystal shear show significant differences in the deformation behavior of the different interfaces, as well as pronounced in-plane anisotropy of the shear strength of the individual interfaces. The critical stresses derived from bicrystal shear simulations are of the same order of magnitude as the one for nucleation and motion of twins in a γ-single crystal, showing that these mechanisms are competitive. In total four different deformation mechanisms, interface migration, twin nucleation and migration, dislocation nucleation, and rigid grain boundary sliding are observed. Their occurrence can be understood based on a multilayer generalized stacking fault energy analysis. This link between physical properties, geometry and deformation mechanism can provide guidelines for future alloy development. kaneko_vickers_2005 ArticleInAPeriodical 2005 June Journal of Materials Science 40 12 http://link.springer.com/10.1007/s10853-005-2690-4 https://doi.org/10.1007/s10853-005-2690-4 3231-3236 KanekoY MizutaY NishijimaY HashimotoS Vickers hardness and deformation of Ni/Cu nano-multilayers electrodeposited on copper substrates Kim_2014 ArticleInAPeriodical Elsevier BV 2014 feb Journal of the Mechanics and Physics of Solids 63 https://doi.org/10.1016%2Fj.jmps.2013.10.001 94-112 KimWK LuskinM PerezD VoterAF TadmorEB Hyper-QC: An accelerated finite-temperature quasicontinuum method using hyperdynamics kim_modified_2006 ArticleInAPeriodical 2006 Physical Review B - Condensed Matter and Materials Physics 74 1 https://doi.org/10.1103/PhysRevB.74.014101 KimYoungMin LeeByeongJoo BaskesMI Modified embedded-atom method interatomic potentials for Ti and Zr Semiempirical interatomic potentials for hcp elements, Ti and Zr, have been developed based on the MEAM ?modified embedded-atom method? formalism. The new potentials do not cause the stability problem previ- ously reported in MEAM for hcp elements, and describe wide range of physical properties ?bulk properties, point defect properties, planar defect properties, and thermal properties? of pure Ti and Zr, in good agreement with experimental information. The applicability of the potentials to atomistic approaches for investigation of various materials behavior ?slip, irradiation, amorphous behavior, etc.? in Ti or Zr-based alloys is demonstrated by showing that the related material properties are correctly reproduced using the present potentials and that the potentials can be easily extended to multicomponent systems. kim_plastic_2000 ArticleInAPeriodical 2000 Acta Materialia 48 2 https://doi.org/10.1016/S1359-6454(99)00353-5 493-504 KimHS EstrinY BushMB Plastic deformation behaviour of fine-grained materials A phase mixture model in which a polycrystalline material is regarded as a mixture of a crystalline phase and a grain-boundary phase is presented. The model aims to describe the plastic deformation behaviour of fine-grained materials. The mechanical properties of the crystalline phase are modelled using unified viscoplastic constitutive relations, which take dislocation density evolution and diffusion creep into account. The total strain rate of a crystallite is calculated by summation of the contributions of dislocation, boundary diffusion and lattice diffusion mechanisms. The deformation mechanism for the grain-boundary phase is modelled as a diffusional flow of matter through the grain boundary. Using a simple rule of mixtures, the grain size dependence of the overall plastic deformation behaviour of the material is analysed. Rate effects are also investigated. The results of the calculations are compared with previously published experimental data. Koyama_2020 ArticleInAPeriodical American Association for the Advancement of Science (AAAS) 2020 jun Science Advances 6 23 https://doi.org/10.1126%2Fsciadv.aaz1187 eaaz1187 KoyamaMotomichi Taheri-MousaviSeyedehMohadeseh YanHaoxue KimJinwoo CameronBenjaminClive Moeini-ArdakaniSeyedSina LiJu TasanCemalCem Origin of micrometer-scale dislocation motion during hydrogen desorption Kramer_2002 ArticleInAPeriodical Informa UK Limited 2002 nov Philosophical Magazine A 82 17-18 https://doi.org/10.1080%2F01418610208240448 3375-3381 KramerDE FoeckeT Transmission electron microscopy observations of deformation and fracture in nanolaminated Cu-Ni thin films kumar_m_d_german_c_f_shih_engineering_1981 ArticleInAPeriodical 1981 Kumar M D German C F ShihAuthorsV An Engineering Approach for Elastic-Plastic Fracture Analysis (415) 965,4081 There is no charge for reports requested by EPRI member utilities and affiliates, contributing nonmembers, U.S, utility associations, U.S. government agencies (federal, state, and local), media, and foreign organizations with which EPRI has an information exchange agreement. On request, RRC will send a catalog of EPRI reports. lesar_introduction_2013 Book 2013 www.cambridge.org/9780521845878 https://doi.org/10.1017/CBO9781139033398 LesarRichard Introduction to Computational Materials Science: Fundamentals to Applications Emphasizing essential methods and universal principles, this textbook provides everything students need to understand the basics of simulating materials behavior. All the key topics are covered, from electronic structure methods to microstructural evolution, appendices provide crucial background material, and a wealth of practical resources are available online to complete the teaching package. • Examines modeling materials across a broad range of scales, from the atomic to the mesoscale, providing students with a solid foundation for future study and research. • Presents detailed, accessible explanations of the fundamental equations underpinning mate- rials modeling, and includes a full chapter summarizing essential mathematical background. • Extensive appendices, including essential background on classical and quantum mechanics, electrostatics, statistical thermodynamics and linear elasticity, provide all the background necessary to fully engage with the fundamentals of computational modeling. • Exercises, worked examples, computer codes and discussions of practical implementations methods are all provided online to give students the hands-on experience they need. Li_2010 ArticleInAPeriodical Elsevier BV 2010 aug Scripta Materialia 63 4 https://doi.org/10.1016%2Fj.scriptamat.2010.04.005 363-366 LiNan WangJ HuangJY MisraA ZhangX In situ TEM observations of room temperature dislocation climb at interfaces in nanolayered Al/Nb composites Li_2019 ArticleInAPeriodical Cambridge University Press (CUP) 2019 apr Journal of Materials Research 34 13 https://doi.org/10.1557%2Fjmr.2019.69 2306-2314 LiYang FanZhaochuan LiWeixuan McDowellDavidL ChenYouping A multiscale study of misfit dislocations in PbTe/PbSe(001) heteroepitaxy li_direct_2012 ArticleInAPeriodical 2012 October Microscopy and Microanalysis 18 05 http://www.journals.cambridge.org/abstract_S143192761200133X https://doi.org/10.1017/S143192761200133X 1155-1162 LiNan WangJian MisraAmit HuangJianYu Direct Observations of Confined Layer Slip in Cu/Nb Multilayers \textbackslashtextlessdiv class=”abstract” data-abstract-type=”normal”\textbackslashtextgreater \textbackslashtextlessp\textbackslashtextgreater \textbackslashtextlessspan class=’italic’\textbackslashtextgreaterIn situ\textbackslashtextless/span\textbackslashtextgreater nanoindentation of a 30 nm Cu/20 nm Nb multilayer film in a transmission electron microscope revealed confined layer slip as the dominant deformation mechanism. Dislocations were observed to nucleate from the Cu-Nb interfaces in both layers. Dislocation glide was confined by interfaces to occur within each layer, without transmission across interfaces. Cu and Nb layers co-deformed to large plastic strains without cracking. These microscopy observations provide insights in the unit mechanisms of deformation, work hardening, and recovery in nanoscale metallic multilayers.\textbackslashtextless/p\textbackslashtextgreater \textbackslashtextless/div\textbackslashtextgreater li_dislocation_2010 ArticleInAPeriodical 2010 April Nature 464 7290 http://www.nature.com/articles/nature08929 https://doi.org/10.1038/nature08929 877-880 LiXiaoyan WeiYujie LuLei LuKe GaoHuajian Dislocation nucleation governed softening and maximum strength in nano-twinned metals lin_measuring_2016 ArticleInAPeriodical 2016 Nature Materials 15 11 http://www.nature.com/doifinder/10.1038/nmat4715 https://doi.org/10.1038/nmat4715 1172-1176 LinNeilYC BierbaumMatthew SchallPeter SethnaJamesP CohenItai Measuring nonlinear stresses generated by defects in 3D colloidal crystals The mechanical, structural and functional properties of crystals are determined by their defects1, 2, 3, 4, and the distribution of stresses surrounding these defects has broad implications for the understanding of transport phenomena. When the defect density rises to levels routinely found in real-world materials, transport is governed by local stresses that are predominantly nonlinear1, 5, 6, 7, 8. Such stress fields however, cannot be measured using conventional bulk and local measurement techniques. Here, we report direct and spatially resolved experimental measurements of the nonlinear stresses surrounding colloidal crystalline defect cores, and show that the stresses at vacancy cores generate attractive interactions between them. We also directly visualize the softening of crystalline regions surrounding dislocation cores, and find that stress fluctuations in quiescent polycrystals are uniformly distributed rather than localized at grain boundaries, as is the case in strained atomic polycrystals. Nonlinear stress measurements have important implications for strain hardening9, yield1, 5 and fatigue10. li_role_2018 ArticleInAPeriodical 2018 Applied Surface Science 433 https://doi.org/10.1016/j.apsusc.2017.10.002 957-962 LiYi ZhouQing ZhangShuang HuangPing XuKewei WangFei LuTianjian On the role of weak interface in crack blunting process in nanoscale layered composites Heterointerface in a nanoscale metallic layered composite could improve its crack resistance. However, the influence of metallic interface structures on crack propagation has not been well understood at atomic scale. By using the method of molecular dynamics (MD) simulation, the crack propagation behavior in Cu-Nb bilayer is compared with that in Cu-Ni bilayer. We find that the weak Cu-Nb interface plays an important role in hindering crack propagation in two ways: (i) dislocation nucleation at the interface releases stress concentration for the crack to propagate; (ii) the easily sheared weak incoherent interface blunts the crack tip. The results are helpful for understanding the interface structure dependent crack resistance of nanoscale bicrystal interfaces. Liu_2018 ArticleInAPeriodical Elsevier BV 2018 nov Extreme Mechanics Letters 25 https://doi.org/10.1016%2Fj.eml.2018.10.007 60-65 LiuZ MonclúsMA YangLW Castillo-RodríguezM Molina-AldareguíaJM LLorcaJ Tensile deformation and fracture mechanisms of Cu/Nb nanolaminates studied by in situ TEM mechanical tests lukas_role_2004 ArticleInAPeriodical 2004 Philosophical Magazine 84 3-5 https://doi.org/10.1080/14786430310001610339 317-330 LukášP KunzL Role of persistent slip bands in fatigue Perhaps the most thoroughly studied feature of cyclic plasticity has been persistent slip bands (PSBs) formed in some metals during cyclic loading. The aim of this paper is to delimit the conditions for the occurrence of the PSBs and to discuss their role in the fatigue process in all its stages, that is in cyclic hardening resulting in a saturated stress-strain response, in initiation of fatigue microcracks and in propagation of fatigue cracks. The PSBs are zones of high cyclic slip activity. Therefore the cyclic stress-strain response depends on their volume fraction and on the ratio of cyclic slip activities within the PSBs to those outside the PSB. The cyclic plastic deformation within the PSBs leads to the formation of surface extrusions and intrusions along the traces of the active slip planes; fatigue microcracks start from the surface intrusions. Thus the PSBs play a crucial role in the process of crack initiation. Stage I fatigue cracks usually run along the PSBs. At very early stages of crack propagation these PSBs are formed before the cracks are initiated; later the PSBs are formed in the plastic zones ahead of the cracks. Stage II fatigue cracks often follow the PSBs on the microscopic level in the threshold region. mae_instability_2002 ArticleInAPeriodical 2002 Modelling and Simulation in Materials Science and Engineering 10 205-214 MaeK NobataT IshidaH MotoyamaS HiwatariY Instability of hcp structures in modified embedded atom method By performing isobaric–isothermal molecular dynamics simulations for Ti we have obtained the result that the ‘modified embedded atom method’ potential creates stable structures different from the hcp structure, with a non-ideal c/a ratio that is experimentally stable. The hcp-to-bcc transformation at high temperature is reproduced. However, attempts to make the hcp structure the ground state structure, by adjusting the many-body screening function or by taking the second-nearest neighbour interactions into account, have been unsuccessful. Structural stabilities of other hcp metals have also been examined. Mara_2015 ArticleInAPeriodical Elsevier BV 2015 oct Current Opinion in Solid State and Materials Science 19 5 https://doi.org/10.1016%2Fj.cossms.2015.04.002 265-276 MaraNathanA BeyerleinIreneJ Interface-dominant multilayers fabricated by severe plastic deformation: Stability under extreme conditions Mart_nez_2008 ArticleInAPeriodical Elsevier BV 2008 mar Journal of the Mechanics and Physics of Solids 56 3 https://doi.org/10.1016%2Fj.jmps.2007.06.014 869-895 MartínezE MarianJ ArsenlisA VictoriaM PerladoJM Atomistically informed dislocation dynamics in fcc crystals mastorakos_deformation_2009 ArticleInAPeriodical 2009 April Applied Physics Letters 94 17 http://aip.scitation.org/doi/10.1063/1.3129166 https://doi.org/10.1063/1.3129166 173114 MastorakosIoannisN ZbibHusseinM BahrDavidF Deformation mechanisms and strength in nanoscale multilayer metallic composites with coherent and incoherent interfaces We investigate the deformation behavior of bimetallic and trimetallic nanoscale multilayer metallic composites under biaxial loading using molecular dynamics. Three types of structures were studied: (a) Cu–Ni fcc/fcc bilayer, (b) Cu–Nb fcc/bcc bilayer, and (c) Ni–Cu–Nb fcc/fcc/bcc trilayer. A configuration with a dislocation structure inside is generated by initially loading a perfect structure to a high strain to nucleate dislocations, then completely unloading it and loading it again. The comparison between the deformation behavior of bilayer and trilayer structures revealed that the Cu–Ni is more ductile, the Cu–Nb is stronger, and the trilayer structure exhibits both high strength and ductility. mastorakos_size-dependent_2011 ArticleInAPeriodical 2011 May Journal of Materials Research 26 10 http://www.journals.cambridge.org/abstract_S0884291411001208 https://doi.org/10.1557/jmr.2011.120 1179-1187 MastorakosIoannisN BellouAikaterini BahrDavidF ZbibHusseinM Size-dependent strength in nanolaminate metallic systems \textlessdiv class=”abstract” data-abstract-type=”normal”\textgreater\textlessp\textgreaterThe effect of layer thickness on the hardness of nanometallic material composites with both coherent and incoherent interfaces was investigated using nanoindentation. Then, atomistic simulations were performed to identify the critical deformation mechanisms and explain the macroscopic behavior of the materials under investigation. Nanocomposites of different individual layer thicknesses, ranging from 1–30 nm, were manufactured and tested in nanoindentation. The findings were compared to the stress–strain curves obtained by atomistic simulations. The results reveal the role of the individual layer thickness as the thicker structures exhibit somehow different behavior than the thinner ones. This difference is attributed to the motion of the dislocations inside the layers. However, in all cases the hybrid structure was the strongest, implying that a particular improvement to the mechanical properties of the coherent nanocomposites can be achieved by adding a body-centered cubic layer on top of a face-centered cubic bilayer.\textless/p\textgreater\textless/div\textgreater matthews_defects_1975 ArticleInAPeriodical 1975 July Journal of Crystal Growth 29 3 https://www.sciencedirect.com/science/article/pii/0022024875901712 https://doi.org/10.1016/0022-0248(75)90171-2 273-280 MatthewsJW BlakesleeAE Defects in epitaxial multilayers: II. Dislocation pile-ups, threading dislocations, slip lines and cracks Multilayers composed of many thin layers of GaAs and GaAs0.5P0.5 were grown on GaAs substrates by chemical vapor deposition. They were examined by optical microscopy, electron microscopy and scanning electron microscopy. Slip lines, dislocation pile-ups, threading dislocations, and cracks were found. These defects were made to relieve elastic stresses generated as a result of misfit between the multilayer taken as a whole and its substrate. The roles of dislocation pile-ups and superkinks in the propagation of dislocations through multilayers are discussed. McDowell_2018 BookSection Springer International Publishing 2018 nov Mesoscale Models https://doi.org/10.1007%2F978-3-319-94186-8_5 195-297 McDowellDavidL Multiscale Modeling of Interfaces, Dislocations, and Dislocation Field Plasticity mcdowell_perspective_2010 ArticleInAPeriodical 2010 International Journal of Plasticity 26 9 https://doi.org/10.1016/j.ijplas.2010.02.008 1280-1309 McDowellDavidL A perspective on trends in multiscale plasticity Research trends in metal plasticity over the past 25 years are briefly reviewed. The myriad of length scales at which phenomena involving microstructure rearrangement during plastic flow is discussed, along with key challenges. Contributions of the author’s group over the past 30 years are summarized in this context, focusing on the statistical nature of microstructure evolution and emergent multiscale behavior associated with metal plasticity, current trends and models for length scale effects, multiscale kinematics, the role of grain boundaries, and the distinction of the roles of concurrent and hierarchical multiscale modeling in the context of materials design. © 2010 Elsevier Ltd. Medyanik_2009 ArticleInAPeriodical Elsevier BV 2009 jun Computational Materials Science 45 4 https://doi.org/10.1016%2Fj.commatsci.2009.01.013 1129-1133 MedyanikSergeyN ShaoShuai Strengthening effects of coherent interfaces in nanoscale metallic bilayers mendelev_development_2016 ArticleInAPeriodical 2016 Journal of Chemical Physics 145 15 https://doi.org/10.1063/1.4964654 MendelevMI UnderwoodTL AcklandGJ Development of an interatomic potential for the simulation of defects, plasticity, and phase transformations in titanium New interatomic potentials describing defects, plasticity, and high temperature phase transitions for Ti are presented. Fitting the martensitic hcp-bcc phase transformation temperature requires an efficient and accurate method to determine it. We apply a molecular dynamics method based on determination of the melting temperature of competing solid phases, and Gibbs-Helmholtz integration, and a lattice-switch Monte Carlo method: these agree on the hcp-bcc transformation temperatures to within 2 K. We were able to develop embedded atom potentials which give a good fit to either low or high temperature data, but not both. The first developed potential (Ti1) reproduces the hcp-bcc transformation and melting temperatures and is suitable for the simulation of phase transitions and bcc Ti. Two other potentials (Ti2 and Ti3) correctly describe defect properties and can be used to simulate plasticity or radiation damage in hcp Ti. The fact that a single embedded atom method potential cannot describe both low and h... miller_quasicontinuum_1999 ArticleInAPeriodical 1999 Modelling and Simulation in Materials Science and Engineering 6 5 https://doi.org/10.1088/0965-0393/6/5/008 607-638 MillerR TadmorEB PhillipsR OrtizM Quasicontinuum simulation of fracture at the atomic scale We study the problem of atomic scale fracture using the recently developed quasicontinuum method in which there is a systematic thinning of the atomic-level degrees of freedom in regions where they are not needed. Fracture is considered in two distinct settings. First, a study is made of cracks in single crystals, and second, we consider a crack advancing towards a grain boundary (GB) in its path. In the investigation of single crystal fracture, we evaluate the competition between simple cleavage and crack-tip dislocation emission. In addition, we examine the ability of analytic models to correctly predict fracture behaviour, and find that the existing analytical treatments are too restrictive in their treatment of nonlinearity near the crack tip. In the study of GB-crack interactions, we have found a number of interesting deformation mechanisms which attend the advance of the crack. These include the migration of the GB, the emission of dislocations from the GB, and deflection of the crack front along the GB itself. In each case, these mechanisms are rationalized on the basis of continuum mechanics arguments. MISRA2006146 BookSection Woodhead Publishing 2006 Nanostructure Control of Materials http://www.sciencedirect.com/science/article/pii/B9781855739338500075 https://doi.org/https://doi.org/10.1533/9781845691189.146 146-176 MisraA HanninkRHJ HillAJ 7 - Mechanical behavior of metallic nanolaminates Publisher Summary Nanolaminate materials, also referred to as “superlattices” or “multilayers”, represent a class of composite materials that are made up of alternating nanometer-scale layers of two different materials, where the individual layer thickness may vary from a few atomic layers to a few tens of nanometers. Nanolaminates have been the subject of significant recent research worldwide due to the novel mechanical and physical properties that emerge as the individual layer thickness is reduced to nanometer-scale. Nanolaminates may be metal–metal, metal–intermetallic, metal–ceramic, ceramic–ceramic, or crystalline amorphous. This chapter focuses on the mechanical behavior of metallic nanolaminates. Besides the technological applications, metal–metal systems are studied extensively as model systems for fundamental research on the effects of nanometer length scales and the interface structures on the mechanical properties of nanolaminates. The chapter presents a brief description of the commonly used methods of synthesis, a brief overview of the strengthening mechanisms relevant to nanolaminates. It also presents experimental data on the strength as a function of bilayer period of the nanolaminates and the interpretation of these data in terms of the dislocation pile-up based Hall–Petch model. Single dislocation-based deformation models are developed to account for the increasing strength with decreasing layer thickness at length scales where the continuum Hall–Petch model is not applicable. The chapter describes atomistic modeling that predicts the limiting strength value for these nanolaminates and discusses the deformation behavior of nanolaminates subjected to large plastic strains to highlight the dislocation storage, work hardening, and texture evolution in these materials. misra_length-scale-dependent_2005 ArticleInAPeriodical 2005 Acta Materialia 53 18 https://doi.org/10.1016/j.actamat.2005.06.025 4817-4824 MisraA HirthJP HoaglandRG Length-scale-dependent deformation mechanisms in incoherent metallic multilayered composites Nano-indentation hardness as a function of bilayer period has been measured for sputter-deposited Cu-Nb multilayers. For this face-centered cubic/body-centered cubic system with incoherent interfaces, we develop dislocation models for the multilayer flow strength as a function of length scale from greater than a micrometer to less than a nanometer. A dislocation pile-up-based Hall-Petch model is found applicable at the sub-micrometer length scales and the Hall-Petch slope is used to estimate the peak strength of the multilayers. At the few to a few tens of nanometers length scales, confined layer slip of single dislocations is treated as the operative mechanism. The effects of dislocation core spreading along the interface, interface stress and interface dislocation arrays on the confined layer slip stress are incorporated in the model to correctly predict the strength increase with decreasing layer thickness. At layer thicknesses of a few nanometers or less, the strength reaches a peak. We postulate that this peak strength is set by the interface resistance to single dislocation transmission, and calculate the transition from confined layer slip to an interface cutting mechanism. © 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Moering_2015 ArticleInAPeriodical Elsevier BV 2015 nov Scripta Materialia 108 https://doi.org/10.1016%2Fj.scriptamat.2015.06.027 100-103 MoeringJordan MaXiaolong ChenGuizhen MiaoPifeng LiGuozhong QianGang MathaudhuSuveen ZhuYuntian The role of shear strain on texture and microstructural gradients in low carbon steel processed by Surface Mechanical Attrition Treatment narita_crack-tip_1989 Book 1989 30 11 https://doi.org/10.2320/matertrans1989.30.895 NaritaNobutaka HigashidaKenji ToriiTakeshi Crack-tip Shielding by Dislocation and Fracture Toughness in NaCl Crystals N_hring_2018 ArticleInAPeriodical Elsevier BV 2018 oct Acta Materialia 158 https://doi.org/10.1016%2Fj.actamat.2018.05.027 95-117 NöhringWolframGeorg CurtinWA Cross-slip of long dislocations in FCC solid solutions nieh_hall-petch_1991 ArticleInAPeriodical 1991 Scripta Metallurgica et Materiala 25 4 https://doi.org/10.1016/0956-716X(91)90256-Z 955-958 NiehTG WadsworthJ Hall-petch relation in nanocrystalline solids It is well known that the Hall-Petch (HP) equation can describe the relationship between yield strength and grain size in conventional metal alloys [1]. The HP relation predicts that strength or hardness should increase with decreasing grain size. Recently, several studies on nanocrystalline materials have reported observations of a normal HP relation but also an inverse HP relation, that is, a hardness increase with increasing grain size [2-7]. (It is noted that nanocrystalline materials primarily consist of perfect lattices within their grains; that is, cells and subgrains are not observed within grains [8].) The purpose of the present paper is to offer an explanation for this apparent controversy. nizolek_tensile_2016 ArticleInAPeriodical 2016 February Applied Physics Letters 108 5 http://aip.scitation.org/doi/10.1063/1.4941043 https://doi.org/10.1063/1.4941043 051903 NizolekThomas BeyerleinIreneJ MaraNathanA AvalloneJaclynT PollockTresaM Tensile behavior and flow stress anisotropy of accumulative roll bonded Cu-Nb nanolaminates The flow stress, ductility, and in-plane anisotropy are evaluated for bulk accumulative roll bonded copper-niobium nanolaminates with layer thicknesses ranging from 1.8 μm to 15 nm. Uniaxial tensile tests conducted parallel to the rolling direction and transverse direction demonstrate that ductility generally decreases with decreasing layer thickness; however, at 30 nm, both high strengths (1200 MPa) and significant ductility (8%) are achieved. The yield strength increases monotonically with decreasing layer thickness, consistent with the Hall-Petch relationship, and significant in-plane flow stress anisotropy is observed. Taylor polycrystal modeling is used to demonstrate that crystallographic texture is responsible for the in-plane anisotropy and that the effects of texture dominate even at nanoscale layer thicknesses. noauthor_concurrent_nodate BookSection Concurrent Atomistic-Continuum Simulation of Defects in Polyatomic Ionic Materials noauthor_ref_62.pdf_nodate Book Ref_62.pdf Nos__1991 ArticleInAPeriodical Oxford University Press (OUP) 1991 Progress of Theoretical Physics Supplement 103 https://doi.org/10.1143%2Fptps.103.1 1-46 NoséShuichi Constant Temperature Molecular Dynamics Methods nye_geometrical_1953 ArticleInAPeriodical 1953 March Acta Metallurgica 1 2 https://www.sciencedirect.com/science/article/pii/0001616053900546 https://doi.org/10.1016/0001-6160(53)90054-6 153-162 NyeJF Some geometrical relations in dislocated crystals When a single crystal deforms by glide which is unevenly distributed over the glide surfaces the lattice becomes curved. The constant feature of distortion by glide on a single set of planes is that the orthogonal trajectories of the deformed glide planes (the c-axes in hexagonal metals) are straight lines. This leads to the conclusion that in polygonisation experiments on single hexagonal metal crystals the polygon walls are planes, while the glide planes are deformed into cylinders whose sections are the involutes of a single curve. The analysis explains West’s observation that the c-axes in bent crystals of corundum are straight lines. For double glide on two orthogonal sets of planes there is a complete analogy between the geometrical properties of the distorted glide planes and those of the “slip-lines” in the mathematical theory of plasticity. More general cases are discussed and formulae are derived connecting the density of dislocations with the lattice curvatures. For a three-dimensional network of dislocations the “state of dislocation” of a region is shown to be specified by a second-rank tensor, which has properties like those of a stress tensor except that it is not symmetrical. Quand un monocristal est déformé par glissement, qui nest pas uniformément distribué sur les surfaces de glissement, le réseau devient courbé. La caractéristique constante de distorsion par glissement sur un soul groupe de plans est, quo les trajectories orthogonales des plans de glissement déformes (les axes-c dans les métaux hexagonaux) sont des droites. Ceci conduit à la conclusion, que dans les essais de polygonisation sur des monocristaux des métaux hexagonaux, les faces des polygones sont planes, alors quo les plans de glissement sont déformés en des cylindres, dont les sections sont des développantes d’une seule courbe. L’analyse explique l’observation de West, quo les axes-c dans des cristaux fléchis de corindon sont des droites. Pour le glissement double sur deux groupes orthogonaux de plans il y a une analogie complète entre les propriétés géométriques des plans de glissement déformés et celles des lignes de glissement Bans la théorie mathématique de la plasticité. Des cas plus généraux sont discutés et des formules joignant la densité des dislocations aux curvaures du réseau sont déduites. Il est montré quo pour un réseau de dislocations à trois dimensions “l’état de dislocation” d’une region est spécifié par un tenseur de second rang, qui a des propriétés semblables à celles du tenseur de tension, à l’éxception du fait, qu’il n’est pas symétrique. Wenn Einkristalle durch Gleitung verformt werden, and die Gleitung sich ungleichmässig über die Gleitebenen verteilt, dann wird das Kristallgitter “verbogen.” Eine der immer wiederkehrenden Begleiterscheinungen der Verformung durch Gleitung im Fall einer einzigen Translationsebene ist, class die Orthogonal trajektorien der verformten Gleitebenen (in hexogonalen Metallen die c-Achsen) Graden sind. Daraus kann man schliessen, dass in Polygon isationsexperimenten an hexogonalen. Einkristallen die Wände der Polygone Ebenen sind, während sich die Gleitebenen zu Zylindern verformt haben, deren Schnitte die Evoluten einer einzigen Kurve sind. Diese Analyse erklärt die Beobachtung von West, dass die c-Achsen von “gebogenen” Korund Kristallen Graden sind. Im Falle einer doppelten Gleitung auf zwei auf einander senkrechten Gleitebenen besteht eine völlige Analogie zwischen den geometrischen ,Eigenschaften der verformten Gleitebenen and den “Gleitlinien” in der mathematischen Theorie der Plastizität. Allgemeine Fälle werden diskutiert und Formeln abgeleitet, die die Dichte der Versetzungen mit der Biegung des Gitters verknüpft. Es wird gezeigt, dass in einem dreidimensionalen Netzwerk von Versetzungen der “Versetzungszustand” eines Bereiches als Tensor zweiter Ordnung dargestellt werden kann, dessen Eigenschaften denen des Spannungstensors ähnlich sind, der jedoch mcht symmetrisch ist. of_colorado_lumped_2010 ArticleInAPeriodical 2010 Introduction To Finite Element Mehtods 31.1-31.23 of ColoradoUniversity Lumped and Consisitent Mass Matrices onat_optimized_2014 ArticleInAPeriodical 2014 Journal of Physics Condensed Matter 26 3 https://doi.org/10.1088/0953-8984/26/3/035404 OnatBerk DurukanoǧluSondan An optimized interatomic potential for Cu-Ni alloys with the embedded-atom method We have developed a semi-empirical and many-body type model potential using a modified charge density profile for Cu–Ni alloys based on the embedded-atom method (EAM) formalism with an improved optimization technique. The potential is determined by fitting to experimental and first-principles data for Cu, Ni and Cu–Ni binary compounds, such as lattice constants, cohesive energies, bulk modulus, elastic constants, diatomic bond lengths and bond energies. The generated potentials were tested by computing a variety of properties of pure elements and the alloy of Cu, Ni: the melting points, alloy mixing enthalpy, lattice specific heat, equilibrium lattice structures, vacancy formation and interstitial formation energies, and various diffusion barriers on the (100) and (111) surfaces of Cu and Ni. parrinello_polymorphic_1981 ArticleInAPeriodical 1981 December Journal of Applied Physics 52 12 http://aip.scitation.org/doi/10.1063/1.328693 https://doi.org/10.1063/1.328693 7182-7190 ParrinelloM RahmanA Polymorphic transitions in single crystals: A new molecular dynamics method A new Lagrangian formulation is introduced. It can be used to make molecular dynamics (MD) calculations on systems under the most general, externally applied, conditions of stress. In this formulation the MD cell shape and size can change according to dynamical equations given by this Lagrangian. This new MD technique is well suited to the study of structural transformations in solids under external stress and at finite temperature. As an example of the use of this technique we show how a single crystal of Ni behaves under uniform uniaxial compressive and tensile loads. This work confirms some of the results of static (i.e., zero temperature) calculations reported in the literature. We also show that some results regarding the stress‐strain relation obtained by static calculations are invalid at finite temperature. We find that, under compressive loading, our model of Ni shows a bifurcation in its stress‐strain relation; this bifurcation provides a link in configuration space between cubic and hexagonal c... Pascuet_2019 ArticleInAPeriodical Elsevier BV 2019 jun Journal of Nuclear Materials 519 https://doi.org/10.1016%2Fj.jnucmat.2019.04.007 265-273 PascuetMI MonnetG BonnyG MartínezE LimJJH BurkeMG MalerbaL Solute precipitation on a screw dislocation and its effects on dislocation mobility in bcc Fe Pedrazzini_2016 ArticleInAPeriodical Elsevier BV 2016 aug Materials Science and Engineering: A 672 https://doi.org/10.1016%2Fj.msea.2016.07.007 175-183 PedrazziniS GalanoM AudebertF CollinsDM HofmannF AbbeyB KorsunskyAM LieblichM EscorialAGarcia SmithGDW Strengthening mechanisms in an Al-Fe-Cr-Ti nano-quasicrystalline alloy and composites pei_tunable_2018 ArticleInAPeriodical 2018 Materials and Design 153 September https://doi.org/10.1016/j.matdes.2018.04.085 232-241 PeiZongrui ShengHoward ZhangXie LiRui SvendsenBob Tunable twin stability and an accurate magnesium interatomic potential for dislocation-twin interactions We showed that there are two variants of twin boundaries for each twin system in hexagonal close-packed materials in our previous study. In this work we further demonstrate that the mechanical stability of these two twin variants in Mg are controlled by their energies and theoretically tunable. In the second part of this work, we continue to incorporate this information of twin boundaries into a newly developed embedded-atom-method (EAM) potential for pure Mg. In addition to twins, the other important information of dislocations and stacking faults is also included, which renders our potential among one of the rare comprehensively optimized ones. Therefore our potential is supposed to be able to accurately capture the physics of not only single defect but also defect-defect interactions. The defect-defect interactions have not been adequately addressed, since modeling their long-range force fields based on density functional theory is computationally too expensive. The new potential will supply new momentum to the study of defect-defect (such as twin-dislocation) interactions and the defect-controlled mechanical properties in Mg. Our study therefore sheds light on the design of novel Mg alloys with optimized mechanical properties. plimpton_fast_1995 Book 1995 117 1 http://linkinghub.elsevier.com/retrieve/pii/S002199918571039X https://doi.org/10.1006/jcph.1995.1039 PlimptonSteve Fast Parallel Algorithms for Short-Range Molecular Dynamics Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers–the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed. potirniche_molecular_2006 ArticleInAPeriodical 2006 February International Journal of Plasticity 22 2 https://www.sciencedirect.com/science/article/pii/S0749641905000458 https://doi.org/10.1016/J.IJPLAS.2005.02.001 257-278 PotirnicheGP HorstemeyerMF WagnerGJ GullettPM A molecular dynamics study of void growth and coalescence in single crystal nickel Molecular dynamics simulations using Modified Embedded Atom Method (MEAM) potentials were performed to analyze material length scale influences on damage progression of single crystal nickel. Damage evolution by void growth and coalescence was simulated at very high strain rates (108–1010/s) involving four specimen sizes ranging from ≈5000 to 170,000 atoms with the same initial void volume fraction. 3D rectangular specimens with uniform thickness were provided with one and two embedded cylindrical voids and were subjected to remote uniaxial tension at a constant strain rate. Void volume fraction evolution and the corresponding stress–strain responses were monitored as the voids grew under the increasing applied tractions. The results showed that the specimen length scale changes the dislocation pattern, the evolving void aspect ratio, and the stress–strain response. At small strain levels (0–20%), a damage evolution size scale effect can be observed from the damage-strain and stress–strain curves, which is consistent with dislocation nucleation argument of Horstemeyer et al. [Horstemeyer, M.F., Baskes, M.I., Plimpton, S.J., 2001a. Length scale and time scale effects on the plastic flow of FCC metals. Acta Mater. 49, pp. 4363–4374] playing a dominant role. However, when the void volume fraction evolution is plotted versus the applied true strain at large plastic strains (\textbackslashtextgreater20%), minimal size scale differences were observed, even with very different dislocation patterns occurring in the specimen. At this larger strain level, the size scale differences cease to be relevant, because the effects of dislocation nucleation were overcome by dislocation interaction. This study provides fodder for bridging material length scales from the nanoscale to the larger scales by examining plasticity and damage quantities from a continuum perspective that were generated from atomistic results. Priedeman_2018 ArticleInAPeriodical Elsevier BV 2018 dec Acta Materialia 161 https://doi.org/10.1016%2Fj.actamat.2018.09.011 431-443 PriedemanJonathanL RosenbrockConradW JohnsonOliverK HomerEricR Quantifying and connecting atomic and crystallographic grain boundary structure using local environment representation and dimensionality reduction techniques quek_inverse_2016 ArticleInAPeriodical 2016 Journal of the Mechanics and Physics of Solids 88 https://doi.org/10.1016/j.jmps.2015.12.012 252-266 QuekSiuSin ChooiZhengHoe WuZhaoxuan ZhangYongWei SrolovitzDavidJ The inverse hall-petch relation in nanocrystalline metals: A discrete dislocation dynamics analysis When the grain size in polycrystalline materials is reduced to the nanometer length scale (nanocrystallinity), observations from experiments and atomistic simulations suggest that the yield strength decreases (softening) as the grain size is decreased. This is in contrast to the Hall-Petch relation observed in larger sized grains. We incorporated grain boundary (GB) sliding and dislocation emission from GB junctions into the classical DDD framework, and recovered the smaller is weaker relationship observed in nanocrystalline materials. This current model shows that the inverse Hall-Petch behavior can be obtained through a relief of stress buildup at GB junctions from GB sliding by emitting dislocations from the junctions. The yield stress is shown to vary with grain size, d, by ad1/2relationship when grain sizes are very small. However, pure GB sliding alone without further plastic accomodation by dislocation emission is grain size independent. rao_atomistic_2000 ArticleInAPeriodical 2000 September Philosophical Magazine A 80 9 http://www.tandfonline.com/doi/abs/10.1080/01418610008212148 https://doi.org/10.1080/01418610008212148 2011-2040 RaoSI HazzledinePM Atomistic simulations of dislocation–interface interactions in the Cu-Ni multilayer system Abstract Experimental results show that a nanolayered composite structure made of two kinds of metals strengthens dramatically as the layer thickness is reduced. In epitaxial systems, this strengthening has been attributed to the modulus, lattice parameter, gamma surface and slip-plane mismatches between adjacent layers. The modulus mismatch (the Koehler barrier) introduces a force between a dislocation and its image in the interface. The lattice parameter mismatch generates oscillating coherency stresses and van der Merwe misfit dislocations at or near the interfaces, which interact with mobile dislocations. The gamma surface (chemical) mismatch introduces a localized force on gliding dislocations due to core energy changes at or near the interfaces. Slip-plane misorientations across the interfaces require mobile screw dislocations to cross-slip for slip transmission and other dislocations to leave a difference dislocation at the interface. In this paper, atomistic simulations using the embedded-atom met... rawat_modelling_2002 ArticleInAPeriodical 2002 RawatSunil MitraNilanjan Modelling and Simulation in Materials Science and Engineering Related content Instability of hcp structures in modified embedded atom method Instability of hcp structures in modified embedded atom method rawat_molecular_2018 ArticleInAPeriodical 2018 Computational Materials Science 141 http://linkinghub.elsevier.com/retrieve/pii/S0927025617304858 https://doi.org/10.1016/j.commatsci.2017.09.015 19-29 RawatSunil MitraNilanjan Molecular dynamics investigation of c-axis deformation of single crystal Ti under uniaxial stress conditions: Evolution of compression twinning and dislocations rice_diuision_1967 ArticleInAPeriodical 1967 May RiceJR Diuision of Engineering THE APPROXIMATE ANALYSIS OF STRAIN CONCENTRATION BY NOTCHES AND CRACKS Department of Defense Advanced Research Projects Agency Contract SD-86 Material Research Progyram ARPA SD-86 REPORT E39 May 1967 ritchie_mechanisms_1988 ArticleInAPeriodical 1988 Materials Science and Engineering 103 1 https://doi.org/10.1016/0025-5416(88)90547-2 15-28 RitchieRO Mechanisms of fatigue crack propagation in metals, ceramics and composites: Role of crack tip shielding Crack tip shielding phenomena, whereby the ”effective crack-driving force” actually experienced at the crack tip is locally reduced, are examined with reference to fatigue crack propagation behavior in metals, composites and ceramics. Sources of shielding are briefly described in terms of mechanisms relying on the production of elastically constrained zones which envelop the crack (zone shielding), on the generation of wedging, bridging or sliding forces between the crack surfaces (contact shielding) and on crack path deflection and meandering. Examples are taken from the fatigue behavior of high strength lithium-containing aluminum alloys, aluminum alloy-aramid fiber-epoxy laminate composites, and zirconia ceramics. It is shown that, whereas crack tip shielding can provide a potent means of enhancing ”resistance” to crack growth, such extrinsic toughening mechanisms can result in the apparently anomalous behavior of ”small cracks” and to the susceptibility of brittle materials to fatigue failure. ?? 1988. rudd_coarse-grained_2005 ArticleInAPeriodical 2005 Physical Review B 72 14 http://link.aps.org/doi/10.1103/PhysRevB.72.144104 https://doi.org/10.1103/PhysRevB.72.144104 1-32 RuddRobert BroughtonJeremy Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature Coarse-grained molecular dynamics (CGMD) is a technique developed as a concurrent multiscale model that couples conventional molecular dynamics (MD) to a more coarse-grained description of the periphery. The coarse-grained regions are modeled on a mesh in a formulation that rudd_concurrent_2000 ArticleInAPeriodical 2000 Physica Status Solidi (B) 217 1 http://doi.wiley.com/10.1002/%28SICI%291521-3951%28200001%29217%3A1%3C251%3A%3AAID-PSSB251%3E3.0.CO%3B2-A https://doi.org/10.1002/(SICI)1521-3951(200001)217:1<251::AID-PSSB251>3.0.CO;2-A 251-291 RuddRE BroughtonJQ Concurrent Coupling of Length Scales in Solid State Systems A strategic objective of computational materials physics is the accurate description of specific materials on length scales spanning the electronic to the macroscopic. We describe progress towards this goal by reviewing a seamless coupling of quantum to statistical to continuum mechanics, involving two models, implemented via parallel algorithms on supercomputers, for unifying finite elements (FE), molecular dynamics (MD) and semi-empirical tight-binding (TB). The first approach, FE/MD/TB Coupling of Length Scales (FE/MD/TB CLS), consists of a hybrid model in which simulations of the three scales are run concurrently with the minimal coupling that guarantees physical consistency. The second approach, Coarse-Grained Molecular Dynamics (CGMD), introduces an effective model, a scale-dependent generalization of finite elements which passes smoothly into molecular dynamics as the mesh is reduced to atomic spacing. These methodologies are illustrated and validated using the examples of crack propagation in silicon and the dynamics of micro-resonators. We also briefly review a number of other approaches to multiscale modeling. ruestes_atomistic_2017 ArticleInAPeriodical 2017 September Crystals 7 10 http://www.mdpi.com/2073-4352/7/10/293 https://doi.org/10.3390/cryst7100293 293 RuestesCarlos AlhafezIyad UrbassekHerbert RuestesCarlosJ AlhafezIyadAlabd UrbassekHerbertM Atomistic Studies of Nanoindentation— A Review of Recent Advances This review covers areas where our understanding of the mechanisms underlying nanoindentation has been increased by atomistic studies of the nanoindentation process. While such studies have been performed now for more than 20 years, recent investigations have demonstrated that the peculiar features of nanoplasticity generated during indentation can be analyzed in considerable detail by this technique. Topics covered include: nucleation of dislocations in ideal crystals, effect of surface orientation, effect of crystallography (fcc, bcc, hcp), effect of surface and bulk damage on plasticity, nanocrystalline samples, and multiple (sequential) indentation. In addition we discuss related features, such as the influence of tip geometry on the indentation and the role of adhesive forces, and how pre-existing plasticity affects nanoindentation. sadananda_role_2001 ArticleInAPeriodical 2001 Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties 81 5 https://doi.org/10.1080/01418610108214441 1283-1303 SadanandaK RamaswamyDoraiNirmalV Role of crack tip plasticity in fatigue crack growth Abstract The effect of plasticity ahead of the crack tip as well as behind the crack tip (crack wake plasticity) on the crack tip driving force is examined using a dislocation model. The plastic zone is approximated by a superdislocation, and linear elasticity is assumed. Dislocation effects are computed using the Lin?Thomson equations. The error involved in the superdislocation approximation is shown to be small. Results indicate that the plasticity ahead of the crack tip induces a large retarding force which a crack must overcome for it to grow. The existence of a threshold in K max for fatigue crack growth as illustrated by the unified two-parameter approach can be related to this crack growth resistance. The plasticity behind the crack tip. however, has a negligible effect on the crack tip driving force and therefore has no effect on the K max threshold. Overload effects, underload effects and fatigue crack growth resistance with increasing K are all relatable to the internal stresses arising from the dislocations in the plastic zone. The two thresholds K max, th and ?K th in the unified approach can be related to the effects of monotonic and cyclic plastic zones. Since the effects of plasticity in the wake are negligible, plasticity-induced closure due to crack wake plasticity is also negligible from the dislocation point of view. A three-zone approximation for the plastic enclave around crack tip is shown to be adequate for the description of the role of plasticity in the crack tip driving force.$\textbackslashbackslash$nAbstract The effect of plasticity ahead of the crack tip as well as behind the crack tip (crack wake plasticity) on the crack tip driving force is examined using a dislocation model. The plastic zone is approximated by a superdislocation, and linear elasticity is assumed. Dislocation effects are computed using the Lin?Thomson equations. The error involved in the superdislocation approximation is shown to be small. Results indicate that the plasticity ahead of the crack tip induces a large retarding force which a crack must overcome for it to grow. The existence of a threshold in K max for fatigue crack growth as illustrated by the unified two-parameter approach can be related to this crack growth resistance. The plasticity behind the crack tip. however, has a negligible effect on the crack tip driving force and therefore has no effect on the K max threshold. Overload effects, underload effects and fatigue crack growth resistance with increasing K are all relatable to the internal stresses arising from the dislocations in the plastic zone. The two thresholds K max, th and ?K th in the unified approach can be related to the effects of monotonic and cyclic plastic zones. Since the effects of plasticity in the wake are negligible, plasticity-induced closure due to crack wake plasticity is also negligible from the dislocation point of view. A three-zone approximation for the plastic enclave around crack tip is shown to be adequate for the description of the role of plasticity in the crack tip driving force. Saito_1999 ArticleInAPeriodical Elsevier BV 1999 jan Acta Materialia 47 2 https://doi.org/10.1016%2Fs1359-6454%2898%2900365-6 579-583 SaitoY UtsunomiyaH TsujiN SakaiT Novel ultra-high straining process for bulk materials—development of the accumulative roll-bonding (ARB) process Sangid_2011 ArticleInAPeriodical Elsevier BV 2011 jan Acta Materialia 59 1 https://doi.org/10.1016%2Fj.actamat.2010.09.032 283-296 SangidMichaelD EzazTawhid SehitogluHuseyin RobertsonIanM Energy of slip transmission and nucleation at grain boundaries schiotz_maximum_2003 ArticleInAPeriodical 2003 April Science (New York, N.Y.) 301 http://www.ncbi.nlm.nih.gov/pubmed/11935012 https://doi.org/10.1126/science.1071040 1357-1359 SchiotzJakob JacobsenKarsten A Maximum in the Strength of Nanocrystalline Copper We used molecular dynamics simulations with system sizes up to 100 million atoms to simulate plastic deformation of nanocrystalline copper. By varying the grain size between 5 and 50 nanometers, we show that the flow stress and thus the strength exhibit a maximum at a grain size of 10 to 15 nanometers. This maximum is because of a shift in the microscopic deformation mechanism from dislocation-mediated plasticity in the coarse-grained material to grain boundary sliding in the nanocrystalline region. The simulations allow us to observe the mechanisms behind the grain-size dependence of the strength of polycrystalline metals. schuh_hall-petch_2002 ArticleInAPeriodical 2002 Scripta Materialia 46 10 https://doi.org/10.1016/S1359-6462(02)00062-3 735-740 SchuhCA NiehTG YamasakiT Hall-Petch breakdown manifested in abrasive wear resistance of nanocrystalline nickel The abrasion resistance of electrodeposited nanocrystalline nickel is investigated using the nanoscratch technique with a ramping load. At the finest grain sizes studied (12-14 nm), a breakdown in Hall-Petch hardening is observed directly in hardness data, as well as indirectly in scratch resistance. The changes in abrasive wear behavior are quantitatively commensurate with the changes in hardness, despite the apparent transition in deformation mechanisms at the finest grain sizes. © 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. S_enz_Trevizo_2020 ArticleInAPeriodical IOP Publishing 2020 may Nanotechnology 31 29 https://doi.org/10.1088%2F1361-6528%2Fab803f 292002 Sáenz-TrevizoA HodgeAM Nanomaterials by design: a review of nanoscale metallic multilayers Shao_2010 ArticleInAPeriodical IOP Publishing 2010 may Modelling and Simulation in Materials Science and Engineering 18 5 https://doi.org/10.1088%2F0965-0393%2F18%2F5%2F055010 055010 ShaoS MedyanikSN Interaction of dislocations with incoherent interfaces in nanoscale FCC–BCC metallic bi-layers Shao_2013a ArticleInAPeriodical ASME International 2013 mar Journal of Engineering Materials and Technology 135 2 https://doi.org/10.1115%2F1.4023672 ShaoS ZbibHM MastorakosI BahrDF Effect of Interfaces in the Work Hardening of Nanoscale Multilayer Metallic Composites During Nanoindentation: A Molecular Dynamics Investigation Shao_2013 ArticleInAPeriodical Springer Science and Business Media LLC 2013 aug Scientific Reports 3 1 https://doi.org/10.1038%2Fsrep02448 ShaoShuai WangJian MisraAmit HoaglandRichardG Spiral Patterns of Dislocations at Nodes in (111) Semi-coherent FCC Interfaces Shao_2014 ArticleInAPeriodical AIP Publishing 2014 jul Journal of Applied Physics 116 2 https://doi.org/10.1063%2F1.4889927 023508 ShaoShuai WangJ MisraAmit Energy minimization mechanisms of semi-coherent interfaces Shao_2015 ArticleInAPeriodical Elsevier BV 2015 oct Acta Materialia 98 https://doi.org/10.1016\%2Fj.actamat.2015.07.044 206-220 ShaoShuai WangJian BeyerleinIreneJ MisraAmit Glide dislocation nucleation from dislocation nodes at semi-coherent {1 1 1} Cu–Ni interfaces Shao_2020 BookSection Springer International Publishing 2020 Handbook of Materials Modeling https://doi.org/10.1007%2F978-3-319-44677-6_86 1049-1078 ShaoShuai ZhouCaizhi MisraAmit WangJian Mesoscale Modeling of Dislocation-Interactions in Multilayered Materials Shen_2005 ArticleInAPeriodical AIP Publishing 2005 oct Applied Physics Letters 87 14 https://doi.org/10.1063%2F1.2056610 141906 ShenTD SchwarzRB ZhangX Bulk nanostructured alloys prepared by flux melting and melt solidification shen_preparation_2018 ArticleInAPeriodical 2018 International Journal of Electrochemical Science 13 1 https://doi.org/10.20964/2018.01.47 984-993 ShenLida ZhaoKailin QiuMingbo WangXin FanMingzhi Preparation and properties of nano-multilayer films by rotating jet electrodeposition © 2018 The Authors. In the following paper, Cu-Ni multilayer films were prepared by rotating jet electrodeposition (RJE). The Cu plating solution and the Ni plating solution were sprayed alternately during deposition to the rotating cathode surface through the corresponding nozzle. The cross-sectional morphology, microstructure, microhardness, and wear resistance of multilayer films were measured by scanning electron microscope, X-ray diffractometer, microhardness tester, and depth of field microscope, respectively. The results revealed that this novel method had no limit to the technological conditions and avoided the oxidation of the films which existed within the preparation of multilayer films by conventional electrodeposition. The sublayer boundaries of the obtained multilayer films were clear. A semi-coherent interface was formed between the sublayers. The resulting special structure reinforced the properties of the films. The microhardness of the multilayer films increased as the modulation period decreased. When the modulation period was reduced to less than 100 nm, the hardness increased dramatically. In addition, the wear resistance of multilayer films was improved when the modulation period decreased. shewchuk_introduction_1994 ArticleInAPeriodical 1994 Science 49 CS-94-125 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.110.418&rep=rep1&type=pdf%5Cnhttp://www.cs.cmu.edu/ quake-papers/painless-conjugate-gradient.pdf https://doi.org/10.1.1.110.418 64 ShewchukJonathanRichard An Introduction to the Conjugate Gradient Method Without the Agonizing Pain The Conjugate Gradient Method is the most prominent iterative method for solving sparse systems of linear equations. Unfortunately, many textbook treatments of the topic are written with neither illustrations nor intuition, and their victims can be found to this day babbling senselessly in the corners of dusty libraries. For this reason, a deep, geometric understanding of the method has been reserved for the elite brilliant few who have painstakingly decoded the mumblings of their forebears. Nevertheless, the Conjugate Gradient Method is a composite of simple, elegant ideas that almost anyone can understand. Of course, a reader as intelligent as yourself will learn them almost effortlessly. The idea of quadratic forms is introduced and used to derive the methods of Steepest Descent, Conjugate Directions, and Conjugate Gradients. Eigenvectors are explained and used to examine the convergence of the Jacobi Method, Steepest Descent, and Conjugate Gradients. Other topics include preconditioning and the nonlinear Conjugate Gradient Method. I have taken pains to make this article easy to read. Sixty-six illustrations are provided. Dense prose is avoided. Concepts are explained in several differentways. Most equations are coupled with an intuitive interpretation. Shilkrot_2002 ArticleInAPeriodical American Physical Society (APS) 2002 jun Physical Review Letters 89 2 https://doi.org/10.1103%2Fphysrevlett.89.025501 ShilkrotLE MillerRE CurtinWA Coupled Atomistic and Discrete Dislocation Plasticity Shimokawa_2007 ArticleInAPeriodical American Physical Society (APS) 2007 apr Physical Review B 75 14 https://doi.org/10.1103%2Fphysrevb.75.144108 ShimokawaT KinariT ShintakuS Interaction mechanism between edge dislocations and asymmetrical tilt grain boundaries investigated via quasicontinuum simulations Shinoda_2004 ArticleInAPeriodical American Physical Society (APS) 2004 apr Physical Review B 69 13 https://doi.org/10.1103%2Fphysrevb.69.134103 ShinodaWataru ShigaMotoyuki MikamiMasuhiro Rapid estimation of elastic constants by molecular dynamics simulation under constant stress smirnov_introduction_2008 ArticleInAPeriodical 2008 Acta Applicandae Mathematicae 11 2 https://doi.org/10.1007/BF00047288 193-195 SmirnovDraftAV An introduction to tensor calculus, relativity, and cosmology I wrote this book in a ”do-it-yourself” style so that I give only a draft of tensor theory, which includes formulating definitions and theorems and giving basic ideas and formulas. All other work such as proving consistence of definitions, deriving formulas, proving theorems or completing details to proofs is left to the reader in the form of numerous exercises. I hope that this style makes learning the subject really quick and more effective for understanding and memorizing. Snel_2017 ArticleInAPeriodical Springer Science and Business Media LLC 2017 aug JOM 69 11 https://doi.org/10.1007%2Fs11837-017-2533-1 2214-2226 SnelJ MonclúsMA Castillo-RodríguezM MaraN BeyerleinIJ LlorcaJ Molina-AldareguíaJM Deformation Mechanism Map of Cu/Nb Nanoscale Metallic Multilayers as a Function of Temperature and Layer Thickness sobie_modal_2017 ArticleInAPeriodical 2017 Acta Materialia 134 https://doi.org/10.1016/j.atmosenv.2014.01.021 203-210 SobieCameron CapolungoLaurent McDowellDavidL MartinezEnrique Modal Analysis of Dislocation Vibration and Reaction Attempt Frequency sobie_scale_2017 ArticleInAPeriodical 2017 Journal of the Mechanics and Physics of Solids 105 http://linkinghub.elsevier.com/retrieve/pii/S0022509616301296 https://doi.org/10.1016/j.jmps.2017.05.004 161-178 SobieCameron CapolungoLaurent McDowellDavidL MartinezEnrique Scale transition using dislocation dynamics and the nudged elastic band method sobie_thermal_2017 ArticleInAPeriodical 2017 Journal of the Mechanics and Physics of Solids 105 https://doi.org/10.1016/j.jmps.2017.05.003 150-160 SobieCameron CapolungoLaurent McDowellDavidL MartinezEnrique Thermal activation of dislocations in large scale obstacle bypass Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented. streitz_surface-stress_1994 ArticleInAPeriodical 1994 April Physical Review B 49 15 https://link.aps.org/doi/10.1103/PhysRevB.49.10707 https://doi.org/10.1103/PhysRevB.49.10707 10707-10716 StreitzFH CammarataRC SieradzkiK Surface-stress effects on elastic properties. II. Metallic multilayers stueber_concepts_2009 ArticleInAPeriodical 2009 August Journal of Alloys and Compounds 483 1-2 https://www.sciencedirect.com/science/article/pii/S0925838808018781 https://doi.org/10.1016/J.JALLCOM.2008.08.133 321-333 StueberM HolleckH LeisteH SeemannK UlrichS ZiebertC Concepts for the design of advanced nanoscale PVD multilayer protective thin films Technological challenges in future surface engineering applications demand continuously new material solutions offering superior properties and performance. Concepts for the design of such advanced multifunctional materials can be systematically evolved and verified by means of physical vapour deposition. The classical multilayer coating concept today is well established and widely used for the design of protective thin films for wear and tribological applications. It has proven great potential for the development of novel thin film materials with tailored properties. In the past decade, the emerging new class of nanoscale coatings has offered to the material scientists an even more powerful toolbox for the engineering thin film design through a combination of the multilayer concept with new nano-coatings. Some examples are the use and integration of low friction carbon-based nanocomposites in advanced multilayer structures or the stabilization of a specific coating in another structure in a nanolaminated multilayer composite. This paper reviews the latest developments in hard, wear-resistant thin films based on the multilayer coating concept. It describes the integration of nanocrystalline, amorphous and nanocrystalline/amorphous composite materials in multilayers and covers various phenomena such as the superlattice effect, stabilization of materials in another, foreign structure, and effects related to coherent and epitaxial growth. Innovative concepts for future, smart multilayer designs based on an extremely fine structural ordering at the nanoscale are presented as well. Stukowski_2009 ArticleInAPeriodical IOP Publishing 2009 dec Modelling and Simulation in Materials Science and Engineering 18 1 https://doi.org/10.1088%2F0965-0393%2F18%2F1%2F015012 015012 StukowskiAlexander Visualization and analysis of atomistic simulation data with OVITO–the Open Visualization Tool stukowski_automated_2012 ArticleInAPeriodical 2012 December Modelling and Simulation in Materials Science and Engineering 20 8 http://stacks.iop.org/0965-0393/20/i=8/a=085007?key=crossref.f9ca36d5353ac80ccfbbfd992a3fd702 https://doi.org/10.1088/0965-0393/20/8/085007 085007 StukowskiAlexander BulatovVasilyV ArsenlisAthanasios Automated identification and indexing of dislocations in crystal interfaces stukowski_computational_2014 ArticleInAPeriodical 2014 March JOM 66 3 http://link.springer.com/10.1007/s11837-013-0827-5 https://doi.org/10.1007/s11837-013-0827-5 399-407 StukowskiAlexander Computational analysis methods in atomistic modeling of crystals This article discusses computational analysis methods typically used in atomistic modeling of crystalline materials and highlights recent developments that can provide better insights into processes at the atomic scale. Topics include the classification of local atomic structures, the transition from atomistics to mesoscale and continuum-scale descriptions, and the automated identification of dislocations in atomistic simulation data. stukowski_dislocation_2010 ArticleInAPeriodical 2010 March Modelling and Simulation in Materials Science and Engineering 18 2 http://stacks.iop.org/0965-0393/18/i=2/a=025016?key=crossref.10589df14cbea9ffd0baaf4f8e1ebad4 https://doi.org/10.1088/0965-0393/18/2/025016 025016 StukowskiAlexander AlbeKarsten Dislocation detection algorithm for atomistic simulations stukowski_elasticplastic_2012 ArticleInAPeriodical 2012 April Modelling and Simulation in Materials Science and Engineering 20 3 http://stacks.iop.org/0965-0393/20/i=3/a=035012?key=crossref.b6b25e8fe841073c7ceeb44ff7f12c4b https://doi.org/10.1088/0965-0393/20/3/035012 035012 StukowskiA ArsenlisA On the elastic–plastic decomposition of crystal deformation at the atomic scale Given two snapshots of an atomistic system, taken at different stages of the deformation process, one can compute the incremental deformation gradient field, F, as defined by continuum mechanics theory, from the displacements of atoms. However, such a kinematic analysis of the total deformation does not reveal the respective contributions of elastic and plastic deformation. We develop a practical technique to perform the multiplicative decomposition of the deformation field, F = FeFp, into elastic and plastic parts for the case of crystalline materials. The described computational analysis method can be used to quantify plastic deformation in a material due to crystal slip- based mechanisms in molecular dynamics and molecular statics simulations. The knowledge of the plastic deformation field, Fp, and its variation with time can provide insight into the number, motion and localization of relevant crystal defects such as dislocations. The computed elastic field, Fe, provides information about inhomogeneous lattice strains and lattice rotations induced by the presence of defects. stukowski_triangulation-based_2014 ArticleInAPeriodical 2014 October Journal of the Mechanics and Physics of Solids 70 https://www.sciencedirect.com/science/article/pii/S0022509614001331 https://doi.org/10.1016/J.JMPS.2014.06.009 314-319 StukowskiAlexander A triangulation-based method to identify dislocations in atomistic models A simple, efficient, and fully automated computer algorithm is described that identifies dislocations in atomistic crystal models and determines their Burgers vectors. To achieve this, the algorithm maps the edges of a Delaunay tessellation to corresponding vectors in an ideal crystal. Dislocations are identified by detecting incompatibilities in this discrete elastic mapping using triangular Burgers circuits. While the presented method is limited to single crystals, it stands out due to its simplicity, straightforward implementation, and computational efficiency. It can provide a bridge from atomistic descriptions of crystals to mesoscale models based on discrete dislocation lines. subedi_strength_2018 ArticleInAPeriodical 2018 Scripta Materialia 145 https://doi.org/10.1016/j.scriptamat.2017.04.009 132-136 SubediSamikshya BeyerleinIreneJ LeSarRichard RollettAnthonyD Strength of nanoscale metallic multilayers The relationship between microstructure, dislocation motion and mechanical response of metallic multilayered nanomaterials is investigated. Several competing theories for the dependence of hardness on layer thickness, namely Confined Layer Slip (CLS) and Hall-Petch (H-P) theories are discussed. Analysis of homophase and heterophase experimental data suggests that Hall-Petch with modified coefficients provides a good fit down to layer thicknesses of about 5 nm, below which experimental data starts to deviate. We suggest that at this layer thickness, dislocations accumulate in the interface, and assuming there is a constant dislocation density in each interface, the strength varies as h−1/2. subramaniyan_continuum_2008 ArticleInAPeriodical 2008 July International Journal of Solids and Structures 45 14-15 https://www.sciencedirect.com/science/article/pii/S0020768308001248 https://doi.org/10.1016/J.IJSOLSTR.2008.03.016 4340-4346 SubramaniyanArunK SunCT Continuum interpretation of virial stress in molecular simulations The equivalence of the virial stress and Cauchy stress is reviewed using both theoretical arguments and numerical simulations. Using thermoelasticity problems as examples, we numerically demonstrate that virial stress is equivalent to the continuum Cauchy stress. Neglecting the velocity terms in the definition of virial stress as many authors have recently suggested, can cause significant errors in interpreting MD simulation results at elevated temperatures (T\textbackslashtextgreater0K). Sun_2020 ArticleInAPeriodical Elsevier BV 2020 apr Journal of Alloys and Compounds 819 https://doi.org/10.1016%2Fj.jallcom.2019.152956 152956 SunYufeng ChenYao TsujiNobuhiro GuanShaokang Microstructural evolution and mechanical properties of nanostructured Cu/Ni multilayer fabricated by accumulative roll bonding sun_disconnections_2018 ArticleInAPeriodical 2018 International Journal of Plasticity October 2017 https://doi.org/10.1016/j.ijplas.2018.02.003 0-1 SunXY FressengeasC TaupinV CordierP CombeN Disconnections, dislocations and generalized disclinations in grain boundary ledges The structure of ledges in otherwise symmetrical tilt boundaries built from atomistic simulations is investigated in copper in terms of continuous dislocation and generalized disclination fields. A ”discrete-to-continuum” crossover method is used to build the relevant kinematic and defect density fields on the basis of discrete atomic displacements appropriately defined in the boundary area. The resulting structure of incompatibility is compared with the so-called disconnection model of boundary ledges. In addition to their dislocation content, which characterizes the elastic displacement discontinuity across the boundary, the ledges appear to be characterized by discontinuities of the elastic rotation and dilatation fields, which are reflected by non-vanishing generalized disclination density fields. Tadmor_1996 ArticleInAPeriodical Informa UK Limited 1996 jun Philosophical Magazine A 73 6 https://doi.org/10.1080%2F01418619608243000 1529-1563 TadmorEB OrtizM PhillipsR Quasicontinuum analysis of defects in solids tadmor2011modeling Book Cambridge New York Cambridge University Press 2011 TadmorEllad Modeling materials : continuum, atomistic, and multiscale techniques Tadmor_2013 ArticleInAPeriodical ASME International 2013 jan Applied Mechanics Reviews 65 1 https://doi.org/10.1115%2F1.4023013 TadmorEB LegollF KimWK DupuyLM MillerRE Finite-Temperature Quasi-Continuum tallman_reconciled_2017 ArticleInAPeriodical 2017 International Journal for Multiscale Computational Engineering 15 6 http://www.dl.begellhouse.com/journals/61fd1b191cf7e96f,627d179355a817c7,7b620f4e4bebdfac.html https://doi.org/10.1615/IntJMultCompEng.2017021859 505-523 TallmanAaronE SwilerLauraP WangYan McDowellDavidL Reconciled top-down and bottom-up hierarchical multiscale calibration of bcc Fe crystal plasticity tasan2015overview ArticleInAPeriodical Annual Reviews 2015 Annual Review of Materials Research 45 391-431 TasanCemalCem DiehlMartin YanDingshun BechtoldMarion RotersFranz SchemmannLars ZhengChengwu PeranioNicola PongeDirk KoyamaMotomichi others, An overview of dual-phase steels: advances in microstructure-oriented processing and micromechanically guided design tench_tensile_1991 ArticleInAPeriodical 1991 December Journal of The Electrochemical Society 138 12 http://jes.ecsdl.org/cgi/doi/10.1149/1.2085495 https://doi.org/10.1149/1.2085495 3757 TenchDM WhiteJT Tensile Properties of Nanostructured Ni-Cu Multilayered Materials Prepared by Electrodeposition Tian_2020 ArticleInAPeriodical Elsevier BV 2020 apr International Journal of Mechanical Sciences 172 https://doi.org/10.1016%2Fj.ijmecsci.2019.105414 105414 TianXia CuiJunzhi YangMei MaKaipeng XiangMeizhen Molecular dynamics simulations on shock response and spalling behaviors of semi-coherent łbrace111 Cu-Al multilayers Tong_2020 ArticleInAPeriodical Elsevier BV 2020 jul Computer Methods in Applied Mechanics and Engineering 366 https://doi.org/10.1016%2Fj.cma.2020.113075 113075 TongQi LiShaofan A concurrent multiscale study of dynamic fracture tschopp_atomistic_2007 Report Georgia Institute of Technology 2007 TschoppMarkA Atomistic Simulations of Dislocation Nucleation in Single Crystals and Grain Boundaries Atomistic Simulations of Dislocation Nucleation The objective of this research is to use atomistic simulations to investigate dislocation nucleation from grain boundaries in face-centered cubic aluminum and copper. This research primarily focuses on asymmetric tilt grain boundaries and has three main components. First, this research uses molecular statics simulations of the structure and energy of these faceted, dissociated grain boundary structures to show that \textbackslashpounds3 asymmetric boundaries can be decomposed into the structural units of the \textbackslashpounds3 symmetric tilt grain boundaries, i.e., the coherent and incoherent twin boundaries. Moreover, the energy for all \textbackslashpounds3 asymmetric boundaries is predicted with only the energies of the \textbackslashpounds3 symmetric boundaries and the inclination angle. Understanding the structure of these boundaries provides insight into dislocation nucleation from these boundaries. Further work into the structure and energy of other low order \textbackslashpounds asymmetric boundaries and the spatial distribution of free volume within the grain boundaries also provides insight into dislocation nucleation mechanisms. Second, this research uses molecular dynamics deformation simulations with uniaxial tension applied perpendicular to these boundaries to show that the dislocation nucleation mechanisms in asymmetric boundaries are highly dependent on the faceted, dissociated structure. Grain boundary dislocation sources can act as perfect sources/sinks for dislocations or may violate this premise by increasing the dislocation content of the boundary during nucleation. Furthermore, simulations under uniaxial tension and uniaxial compression show that nucleation of the second partial dislocation in copper exhibits tension-compression asymmetry. Third, this research explores the development of models that incorporate the resolved stress components on the slip system of dislocation nucleation to predict the atomic stress required for dislocation nucleation from single crystals and grain boundaries. Single crystal simulations of homogeneous dislocation nucleation help define the role of lattice orientation on the nucleation stress for grain boundaries. The resolved stress normal to the slip plane on which the dislocation nucleates plays an integral role in the dislocation nucleation stress and related mechanisms. In summary, the synthesis of various aspects of this work has provided improved understanding of how the grain boundary character influences dislocation nucleation in bicrystals, with possible implications for nanocrystalline materials. tschopp_atomistic_2008 ArticleInAPeriodical 2008 December Computational Materials Science 44 2 https://www.sciencedirect.com/science/article/pii/S0927025608001870 https://doi.org/10.1016/J.COMMATSCI.2008.03.041 351-362 TschoppMA TuckerGJ McDowellDL Atomistic simulations of tension–compression asymmetry in dislocation nucleation for copper grain boundaries Atomistic simulations are used to investigate how grain boundary structure influences dislocation nucleation under uniaxial tension and compression for a specific class of symmetric tilt grain boundaries that contain the E structural unit. After obtaining the minimum energy grain boundary structure, molecular dynamics was employed based on an embedded-atom method potential for copper at 10K. Results show several differences in dislocation nucleation with respect to uniaxial tension and compression. First, the average nucleation stress for all 〈110〉 symmetric tilt grain boundaries is over three times greater in compression than in tension for both the high strain rate and quasistatic simulations. Second, partial dislocations nucleate from the boundary on the {111} slip plane under uniaxial tension. However, partial and full dislocations nucleate from the boundary on the {100} and {111} slip planes under uniaxial compression. The full dislocation nucleation on the {100} plane for boundaries with misorientations near the coherent twin boundary is explained through the higher resolved shear stress on the {100} plane compared to the {111} plane. Last, individual dislocation nucleation mechanisms under uniaxial tension and compression are analyzed. For the vicinal twin boundary under tension, the grain boundary partial dislocation is emitted into the lattice on the same {111} plane that it dissociated onto. For compression of the vicinal twin, the 1/3〈111 〉 disconnection is removed through full dislocation emission on the {100} plane and partial dislocation emission parallel to the coherent twin boundary plane, restoring the boundary to the coherent twin. For the Σ19 boundary, the nearly simultaneous emission of numerous partial dislocations from the boundary result in the formation of the hexagonal close-packed (HCP) phase. Tucker_2009 ArticleInAPeriodical IOP Publishing 2009 dec Modelling and Simulation in Materials Science and Engineering 18 1 https://doi.org/10.1088%2F0965-0393%2F18%2F1%2F015002 015002 TuckerGJ ZimmermanJA McDowellDL Shear deformation kinematics of bicrystalline grain boundaries in atomistic simulations tucker2011atomistic Report Georgia Institute of Technology 2011 TuckerGarrittJ Atomistic simulations of defect nucleation and free volume in nanocrystalline materials Tucker_2011 ArticleInAPeriodical Elsevier BV 2011 dec International Journal of Engineering Science 49 12 https://doi.org/10.1016%2Fj.ijengsci.2011.03.019 1424-1434 TuckerGarrittJ ZimmermanJonathanA McDowellDavidL Continuum metrics for deformation and microrotation from atomistic simulations: Application to grain boundaries Turlo_2018 ArticleInAPeriodical Elsevier BV 2018 jun Acta Materialia 151 https://doi.org/10.1016%2Fj.actamat.2018.03.055 100-111 TurloVladyslav RupertTimothyJ Grain boundary complexions and the strength of nanocrystalline metals: Dislocation emission and propagation Varvenne_2017 ArticleInAPeriodical Elsevier BV 2017 feb Acta Materialia 124 https://doi.org/10.1016%2Fj.actamat.2016.09.046 660-683 VarvenneC LeysonGPM GhazisaeidiM CurtinWA Solute strengthening in random alloys voter_accurate_1986 ArticleInAPeriodical 1986 MRS Online Proceedings Library Archive 82 175-180 VoterArthurF ChenShaoPing Accurate interatomic potentials for Ni, Al, and Ni3Al To obtain meaningful results from atomistic simulations of materials, the interatomic potentials must be capable of reproducing the thermodynamic properties of the system of interest. Pairwise potentials have known deficiencies that make them unsuitable for quantitative investigations of defective regions such as crack tips and free surfaces. Daw and Baskes [Phys. Rev. B 29, 6443 (1984)] have shown that including a local ”volume” term for each atom gives the necessary many-body character without the severe computational dependence of explicit n-body potential terms. Using a similar approach, we have fit an interatomic potential to the Ni3Al alloy system. This potential can treat diatomic Ni2, diatomic Al2 , fcc Ni, fcc Al and L12 Ni Al on an equal footing. Details of the fitting procedure are presented, along with the calculation of some properties not included in the fit. INTRODUCTION Wang_2014 ArticleInAPeriodical Elsevier BV 2014 may International Journal of Plasticity 56 https://doi.org/10.1016%2Fj.ijplas.2013.11.009 156-172 WangJ BeyerleinIJ ToméCN Reactions of lattice dislocations with grain boundaries in Mg: Implications on the micro scale from atomic-scale calculations Wang_2016 ArticleInAPeriodical Informa UK Limited 2016 sep Materials Research Letters 5 1 https://doi.org/10.1080%2F21663831.2016.1225321 1-19 WangJian ZhouQing ShaoShuai MisraAmit Strength and plasticity of nanolaminated materials Wang_2017 ArticleInAPeriodical Elsevier BV 2017 jun Materials Science and Engineering: A 696 https://doi.org/10.1016%2Fj.msea.2017.04.111 503-510 WangZG ZhouW FuLM WangJF LuoRC HanXC ChenB WangXD Effect of coherent L12 nanoprecipitates on the tensile behavior of a fcc-based high-entropy alloy WANG_2019 ArticleInAPeriodical Elsevier BV 2019 aug Transactions of Nonferrous Metals Society of China 29 8 https://doi.org/10.1016%2Fs1003-6326%2819%2965069-7 1621-1630 WANGLin DUQing-lin LIChang CUIXiao-hui ZHAOXing YUHai-liang Enhanced mechanical properties of lamellar Cu/Al composites processed via high-temperature accumulative roll bonding wang_atomistic_2008 ArticleInAPeriodical 2008 Acta Materialia 56 19 https://doi.org/10.1016/j.actamat.2008.07.041 5685-5693 WangJ HoaglandRG HirthJP MisraA Atomistic modeling of the interaction of glide dislocations with ”weak” interfaces Using atomistic modeling and anisotropic elastic theory, the interaction of glide dislocations with interfaces in a model Cu-Nb system was explored. The incoherent Cu-Nb interfaces have relatively low shear strength and are referred to as ”weak” interfaces. This work shows that such interfaces are very strong traps for glide dislocations and, thus, effective barriers for slip transmission. The key aspects of the glide dislocation-interface interactions are as follows. (i) The weak interface is readily sheared under the stress field of an impinging glide dislocation. (ii) The sheared interface generates an attractive force on the glide dislocation, leading to the absorption of dislocation in the interface. (iii) Upon entering the interface, the glide dislocation core readily spreads into an intricate pattern within the interface. Consequently, the glide dislocations in both Cu and Nb crystals are energetically favored to enter the interface when they are located within 1.5 nm from the interface. In addition to the trapping of dislocations in weak interfaces, this paper also discusses geometric factors such as the crystallographic discontinuity of slip systems across the Cu/Nb interfaces, which contribute to the difficulty of dislocation transmission across an interface. The implications of these findings to the unusually high strengths experimentally measured in Cu/Nb nanolayered composites are discussed. wang_frank_2013 ArticleInAPeriodical 2013 February Computational Materials Science 68 https://www.sciencedirect.com/science/article/pii/S0927025612006465 https://doi.org/10.1016/J.COMMATSCI.2012.10.042 396-401 WangShuaichuang LuGuo ZhangGuangcai A Frank scheme of determining the Burgers vectors of dislocations in a FCC crystal A Frank scheme based on the Thompson’s tetrahedron is developed to calculate the Burgers vector of dislocations in a face-centered cubic (FCC) crystal during its plastic deformation. A Burgers circuit is located firstly in a deformed crystal with a reference circle surrounding one or more dislocations. The atom-to-atom sequence in a dislocation-free crystal corresponding to the Burgers circuit is determined not from a local reference lattice, but from the edge vectors of the Thompson’s tetrahedron and its mirrors. The final Burgers vector obtained by its Frank definition is accurate, regardless of the position, size and normal direction of the initial reference circle, as long as the same dislocations are surrounded. The present method is validated in determining the Burgers vectors for the dissociation of a perfect dislocation and for the complex reactions of the dislocations from a nanovoid in a deformed crystal under a uniaxial tensile loading. wang_interface_2014 ArticleInAPeriodical 2014 International Journal of Plasticity 53 https://doi.org/10.1016/j.ijplas.2013.07.002 40-55 WangJ ZhangRF ZhouCZ BeyerleinIJ MisraA Interface dislocation patterns and dislocation nucleation in face-centered-cubic and body-centered-cubic bicrystal interfaces Nanolayered metallic composites exhibit unusual high strength at the layer thickness in nanometers. Plastic deformation including nucleation, glide, and transmission of dislocations is strongly related to interface structure and properties. Combining atomistic simulations with the classical Frank-Bilby theory, we studied dislocation structures of semi-coherent interfaces between face-centered-cubic (fcc) and body-centered-cubic (bcc) crystals. An atomically informed Frank-Bilby theory is proposed for quantitative analysis of interface dislocations. The results showed that (1) seven sets of interface dislocations are present in the Nishiyama-Wasserman (NW) interface and two sets of interface dislocation in the Kurdjumov-Sachs (KS) interface although they are misoriented by only ∼5.6; (2) Burgers vectors of interface dislocations can be well defined in a commensurate/coherent dichromatic pattern (CDP) lattice corresponding to the NW interface and the Rotation CDP (RCDP) lattice corresponding to the KS interface; (3) the CDP and RCDP lattices are not simply a geometric average of the two natural lattices; finally we demonstrated that (4) the nucleation of dislocations, including interface dislocation loops corresponding to interface sliding and lattice dislocation loops corresponding to plastic deformation in crystals, are strongly correlated with interface dislocation patterns. © 2013 Elsevier Ltd. All rights reserved. wang_material_2012 ArticleInAPeriodical 2012 September https://digital.lib.washington.edu/researchworks/handle/1773/20802 WangIrene Material Characterization of Electrodeposited Copper-Nickel Nanolaminated Alloy by SEM, EDS, and XRD Thesis (Master’s)–University of Washington, 2012 wang_strong_2015 ArticleInAPeriodical 2015 Nano Letters 15 6 https://doi.org/10.1021/acs.nanolett.5b00694 3865-3870 WangJiangwei SansozFrederic DengChuang XuGang HanGaorong MaoScottX Strong Hall-Petch Type Behavior in the Elastic Strain Limit of Nanotwinned Gold Nanowires © 2015 American Chemical Society.Pushing the limits of elastic deformation in nanowires subjected to stress is important for the design and performance of nanoscale devices from elastic strain engineering. Particularly, introducing nanoscale twins has proved effective in rising the tensile strength of metals. However, attaining ideal elastic strains in nanotwinned materials remains challenging, because nonuniform twin sizes locally affect the yielding behavior. Here, using in situ high-resolution transmission electron microscopy tensile testing of nanotwinned [111]-oriented gold nanowires, we report direct lattice-strain measurements that demonstrate a strong Hall-Petch type relationship in the elastic strain limit up to 5.3%, or near the ideal theoretical limit, as the twin size is decreased below 3 nm. It is found that the largest twin in nanowires with irregular twin sizes controls the slip nucleation and yielding processes in pure tension, which is in agreement with earlier atomistic simulations. Continuous hardening behavior without loss of strength or softening is observed in nanotwinned single-crystalline gold nanowires, which differs from the behaviors of bulk nanocrystalline and nanotwinned-nanocrystalline metals. These findings are of practical value for the use of nanotwinned metallic and semiconductor nanowires in strain-engineered functional microdevices. (Graph Presented.) warner_atomistic_2006 ArticleInAPeriodical 2006 International Journal of Plasticity 22 4 https://doi.org/10.1016/j.ijplas.2005.04.014 754-774 WarnerDH SansozF MolinariJF Atomistic based continuum investigation of plastic deformation in nanocrystalline copper A continuum model of nanocrystalline copper was developed based on results from independent atomistic calculations on 11 bicrystals containing high angle grain boundaries. The relationship between grain boundary structure and its mechanical response was investigated. Based on the atomistic calculations; a constitutive law for grain boundary interfaces was implemented within a finite element calculation that consisted of a microstructure loaded in compression. The yield strength as a function of grain size was compared to experimental data and molecular dynamics results. Calculations were performed to demonstrate the relationship between intragranular plasticity and grain boundary sliding. © 2005 Elsevier Ltd. All rights reserved. warner_rate_2007 ArticleInAPeriodical 2007 Nature Materials 6 11 https://doi.org/10.1038/nmat2030 876-881 WarnerDH CurtinWA QuS Rate dependence of crack-tip processes predicts twinning trends in f.c.c. metals Crack-tip behaviour in metals is among the most basic problems in mechanics of materials. Yet, long-standing experimental evidence suggests that crack-tip twinning in face-centred-cubic (f.c.c.) metals is highly dependent on the material, temperature and loading rate, and previous simulations and models predict twinning in aluminium, where it has never been observed. Here, this discrepancy between theory and experiment is resolved through a new model guided and validated by extensive multiscale simulations. Both the analytic model and simulations reveal a transition from crack-tip twinning at short times to full dislocation formation at long times. Applied to a host of f.c.c. metals, the model agrees with experimental trends as it predicts large differences in the thermal activation needed for full dislocation emission to dominate. More broadly, this work demonstrates the necessity of multiscale modelling and attention to rate dependence for accurate description of material behaviour and computationally guided material design. was_deformation_1996 ArticleInAPeriodical 1996 September Thin Solid Films 286 1-2 https://www.sciencedirect.com/science/article/pii/S0040609096089055 https://doi.org/10.1016/S0040-6090(96)08905-5 1-31 WasGS FoeckeT Deformation and fracture in microlaminates The utility of microlaminates in engineering applications depends ultimately on their strength and toughness. While the properties of monolithic films and coatings can be controlled through crystal structure and microstructure, the properties of microlaminates are a sensitive function of the interfaces. It is the large number of interfaces in a microlaminate that determines the unique behavior of this special type of composite. This review begins with a property-based definition of a microlaminate. The mechanisms by which microlaminates deform plastically are reviewed and evaluated in the context of data on metal-metal, metal-intermetallic, metal-ceramic and ceramic-ceramic systems. It is evident that in addition to layer geometry, the layer microstructure plays a major role in determining the operative deformation mechanism. The fracture processes in a microlaminate are examined in the context of the layer strength, microstructure, defects and crack-tip-dislocation processes. High toughnesses in microlaminate materials can be attained through a combination of mechanisms, and their effectiveness depends critically on the ability to affect the magnitude and shape of the stress field at the tip of the crack. The study of deformation and fracture in microlaminates is still a relatively young field in materials science. However, while our understanding of these processes is still quite incomplete, it is improving rapidly with advances in experiment, theory and modeling capability. Weygand_1999 ArticleInAPeriodical Informa UK Limited 1999 may Philosophical Magazine B 79 5 https://doi.org/10.1080%2F13642819908205744 703-716 WeygandD BréchetY LépinouxJ GustW Three-dimensional grain growth: A vertex dynamics simulation Williams_2006 ArticleInAPeriodical IOP Publishing 2006 may Modelling and Simulation in Materials Science and Engineering 14 5 https://doi.org/10.1088%2F0965-0393%2F14%2F5%2F002 817-833 WilliamsPL MishinY HamiltonJC An embedded-atom potential for the Cu–Ag system williams_performance_1991 ArticleInAPeriodical 1991 October Concurrency: Practice and Experience 3 5 http://doi.wiley.com/10.1002/cpe.4330030502 https://doi.org/10.1002/cpe.4330030502 457-481 WilliamsRoyD Performance of dynamic load balancing algorithms for unstructured mesh calculations wood_lattice_2002 ArticleInAPeriodical 2002 ConferenceProceedings of the Physical Society 80 3 https://doi.org/10.1088/0370-1328/80/3/323 783-786 WoodRM The Lattice Constants of High Purity Alpha Titanium Lattice constants have been determined for a specimen of alpha titanium of greater purity than hitherto examined. Values of a0 = 2.95111 \textbackslashAA ± 6 × 10-5 and c0 = 4.684 33 \textbackslashAA ± 10 × 10-5 differ significantly from previous, accepted figures obtained by Clark in 1949. Comparative impurity contents for two grades of pure titanium are given. Wu_2014 ArticleInAPeriodical ConferenceProceedings of the National Academy of Sciences 2014 may ConferenceProceedings of the National Academy of Sciences 111 20 https://doi.org/10.1073%2Fpnas.1324069111 7197-7201 WuX JiangP ChenL YuanF ZhuYT Extraordinary strain hardening by gradient structure Wu_2015 ArticleInAPeriodical ConferenceProceedings of the National Academy of Sciences 2015 nov ConferenceProceedings of the National Academy of Sciences 112 47 https://doi.org/10.1073%2Fpnas.1517193112 14501-14505 WuXiaolei YangMuxin YuanFuping WuGuilin WeiYujie HuangXiaoxu ZhuYuntian Heterogeneous lamella structure unites ultrafine-grain strength with coarse-grain ductility Wu_2018 ArticleInAPeriodical Springer Science and Business Media LLC 2018 aug Journal of Molecular Modeling 24 9 https://doi.org/10.1007%2Fs00894-018-3792-7 WuCheng-Da JiangWen-Xiang Molecular dynamics study on deformation and mechanics of nanoscale Au/Cu multilayers under indentation Wu_2020a ArticleInAPeriodical Informa UK Limited 2020 aug Molecular Simulation 46 15 https://doi.org/10.1080%2F08927022.2020.1806263 1155-1163 WuCheng-Da FangTe-Hua SuWen-Cheng FanYu-Cheng Effects of constituting material and interfacial crack on mechanical response of nanoscale metallic bilayers – a quasi-continuum study Wu_2020 ArticleInAPeriodical Elsevier BV 2020 aug Thin Solid Films 707 https://doi.org/10.1016%2Fj.tsf.2020.138050 138050 WuCheng-Da HuangBo-Xun LiHe-Xing Effects of interfacial defect on deformation and mechanical properties of Cu/Ni bilayer—A molecular dynamics study wu_generalized-stacking-fault_2010 ArticleInAPeriodical 2010 Applied Surface Science 256 11 https://doi.org/10.1016/j.apsusc.2009.12.042 3409-3412 WuXiaozhi WangRui WangShaofeng Generalized-stacking-fault energy and surface properties for HCP metals: A first-principles study We present first-principles calculations on the generalized-stacking-fault (GSF) energies and surface properties for several HCP metals on Mg, Be, Ti, Zn, and Zr, employing density functional theory (DFT) within generalized-gradient-approximation (GGA) and spin-polarized GGA (SGGA) using the Vienna ab initio simulation package (VASP). Using a supercell approach, stacking fault energies for the [1 1over(2, ̄) 0] and [1 0over(1, ̄) 0] slip systems, and surface properties on basal plane (0 0 0 1) have been determined. Our results show that GSF energy is sensitive to the primitive cell volumes and the ratio c / a for HCP metals. A spin-polarized calculations should be considered for transition-metal Ti, Zn, and Zr. The results for Mg from this work are good with ones from the previous ab initio and the experiments. © 2009 Elsevier B.V. All rights reserved. Xiang_2018 ArticleInAPeriodical Elsevier BV 2018 apr International Journal of Plasticity 103 https://doi.org/10.1016%2Fj.ijplas.2017.12.005 23-38 XiangMeizhen LiaoYi WangKun LuGuo ChenJun Shock-induced plasticity in semi-coherent {111} Cu-Ni multilayers Xiong_2012 ArticleInAPeriodical Elsevier BV 2012 oct Scripta Materialia 67 7-8 https://doi.org/10.1016%2Fj.scriptamat.2012.07.026 633-636 XiongLiming McDowellDavidL ChenYouping Nucleation and growth of dislocation loops in Cu, Al and Si by a concurrent atomistic-continuum method Xiong_2015 ArticleInAPeriodical Elsevier BV 2015 feb International Journal of Plasticity 65 https://doi.org/10.1016%2Fj.ijplas.2014.08.002 33-42 XiongLiming XuShuozhi McDowellDavidL ChenYouping Concurrent atomistic–continuum simulations of dislocation–void interactions in fcc crystals xiong_concurrent_2012 ArticleInAPeriodical 2012 February Acta Materialia 60 3 https://www.sciencedirect.com/science/article/pii/S1359645411007786 https://doi.org/10.1016/J.ACTAMAT.2011.11.002 899-913 XiongLiming DengQian TuckerGarritt McDowellDavidL ChenYouping A concurrent scheme for passing dislocations from atomistic to continuum domains This paper presents a concurrent atomistic–continuum (CAC) methodology for three-dimensional dynamic simulation of dislocation nucleation, migration and interaction. The method is based on a new continuum field formulation of balance laws with relevant atomistic information (the arrangements and interactions of atoms) considered. In this work, we show that the new CAC method allows the smooth passage of dislocations through sharp interfaces between the atomistic and the coarse-grained finite element domains without unphysical reflection of dislocations or the need for heuristic rules; meanwhile, complex dislocation phenomena such as dislocation nucleation, dynamic strain bursts associated with nucleation and migration avalanches, formations of Lomer–Cottrell locks, dislocation–rigid boundary interactions, formation of intrinsic and extrinsic stacking faults, deformation twinning, and curved dislocation loops can be reproduced by the CAC method. All of the CAC simulations are directly compared with the corresponding atomic-level molecular dynamics (MD) simulations. The efficiency, accuracy and potential applications of the method are discussed along with necessary additional development of criteria for coarse graining. Xu_2016 Report Georgia Institute of Technology 2016 XuShuozhi The concurrent atomistic-continuum method: Advancements and applications in plasticity of face-centered cubic metals Xu_2017 ArticleInAPeriodical Springer Science and Business Media LLC 2017 mar JOM 69 5 https://doi.org/10.1007%2Fs11837-017-2302-1 814-821 XuShuozhi XiongLiming ChenYouping McDowellDavidL Comparing EAM Potentials to Model Slip Transfer of Sequential Mixed Character Dislocations Across Two Symmetric Tilt Grain Boundaries in Ni Xu_2018 ArticleInAPeriodical Informa UK Limited 2018 may Philosophical Magazine Letters 98 5 https://doi.org/10.1080%2F09500839.2018.1515506 173-182 XuShuozhi LatypovMaratI SuYanqing Concurrent atomistic-continuum simulations of uniaxial compression of gold nano/submicropillars Xu_2019 ArticleInAPeriodical Elsevier BV 2019 aug Acta Materialia 174 https://doi.org/10.1016%2Fj.actamat.2019.05.030 160-172 XuShuozhi McDowellDavidL BeyerleinIreneJ Sequential obstacle interactions with dislocations in a planar array Xu_2020 ArticleInAPeriodical Wiley 2020 aug physica status solidi (b) 257 12 https://doi.org/10.1002%2Fpssb.202000274 2000274 XuShuozhi LiYang ChenYouping Si/Ge (111) Semicoherent Interfaces: Responses to an In-Plane Shear and Interactions with Lattice Dislocations xu_analysis_2016 ArticleInAPeriodical 2016 Journal of the Mechanics and Physics of Solids 96 https://doi.org/10.1016/j.jmps.2016.08.002 460-476 XuShuozhi XiongLiming ChenYouping McDowellDavidL An analysis of key characteristics of the Frank-Read source process in FCC metals A well-known intragranular dislocation source, the Frank-Read (FR) source plays an important role in size-dependent dislocation multiplication in crystalline materials. Despite a number of studies in this topic, a systematic investigation of multiple aspects of the FR source in different materials is lacking. In this paper, we employ large scale quasistatic concurrent atomistic-continuum (CAC) simulations to model an edge dislocation bowing out from an FR source in Cu, Ni, and Al. First, a number of quantities that are important for the FR source process are quantified in the coarse-grained domain. Then, two key characteristics of the FR source, including the critical shear stress and critical dislocation configuration, are investigated. In all crystalline materials, the critical stresses and the aspect ratio of the dislocation half-loop height to the FR source length scale well with respect to the FR source length. In Al, the critical stress calculated by CAC simulations for a given FR source length agrees reasonably well with a continuum model that explicitly includes the dislocation core energy. Nevertheless, the predictions of the isotropic elastic theory do not accurately capture the FR source responses in Cu and Ni, which have a relatively large stacking fault width and elastic anisotropy. Our results highlight the significance of directly simulating the FR source activities using fully 3D models and shed light on developing more accurate continuum models. xu_edge_2016 ArticleInAPeriodical 2016 Scripta Materialia 123 https://doi.org/10.1016/j.scriptamat.2016.06.018 135-139 XuShuozhi XiongLiming ChenYouping McDowellDavidL Edge dislocations bowing out from a row of collinear obstacles in Al The bowing of edge dislocations from a row of collinear obstacles in Al is studied using concurrent atomistic-continuum simulations of submicron-sized realizations containing up to 238 million atoms. Results show that (1) as the number of adjacent bowed-out dislocation segments increases, the critical dislocation depinning stress approaches that for an infinite array of obstacles and (2) for the unstable overall semi-elliptic dislocation configuration, the presence of intermediate obstacles reduces the dislocation half-loop height, but doesn’t affect the critical shear stress. Our work highlights the significance of the effects of adjacent bowed-out segments on cooperative dislocation bow-out. xu_pycac_2018 ArticleInAPeriodical Cambridge University Press 2018 Journal of Materials Research 33 7 857 XuShuozhi PayneThomasG ChenHao LiuYongchao XiongLiming ChenYouping McDowellDavidL PyCAC: The concurrent atomistic-continuum simulation environment xu_quasistatic_2015 ArticleInAPeriodical 2015 International Journal of Plasticity 72 https://doi.org/10.1016/j.ijplas.2015.05.007 91-126 XuShuozhi CheRui XiongLiming ChenYouping McDowellDavidL A quasistatic implementation of the concurrent atomistic-continuum method for FCC crystals In recent years, numerous partitioned-domain methods have been developed to describe dislocation behavior at length scales that are usually inaccessible to most classical atomistic methods. These methods retain full atomistic detail in regions of interest while using a continuum description to reduce the computational burden elsewhere. In most of these methods, however, lattice defects in the continuum are either implemented via constitutive relations, lattice elasticity with dislocation field interactions, or are not permitted at all. In such approaches, the transit of dislocations across the atomistic/continuum interface appeals to approximate heuristics intended to minimize the effects of the interface due to the change from atomistic to continuum degrees of freedom. The concurrent atomistic-continuum (CAC) method, originally developed for addressing dynamic dislocation behavior by Xiong et al. (2011), permits dislocations to propagate in a continuum domain that employs a piecewise continuous finite element description with interelement displacement discontinuities. The method avoids ghost forces at interface between atomistically resolved and coarse-grained domains. CAC has subsequently been used to investigate complex dislocation behavior in face-centered cubic (FCC) metals (Xiong et al., 2012b,a,c, 2015). In this paper, we propose a quasistatic 3-D method to carry out sequential energy-minimized simulations at 0 K. This facilitates study of structure evolution along minimum energy pathways, avoiding over-driven conditions of high rate molecular dynamics. Parallelization steps in code implementation are described. Applications are presented for the quasistatic CAC method in FCC metal plasticity. Comparisons are made with a fully-resolved atomistic method for generalized stacking fault energy, core structure and stress field of a single 60° mixed type dislocation, surface indentation, and 60° mixed type dislocation migration through the interface between atomistic and coarse-grained domains. It is shown that 3-D CAC simulations are useful in substantially reducing the number of degrees of freedom while preserving key characteristics of dislocation structure, stacking faults, and plasticity, including the net Burgers vector and long range fields of interacting dislocations. xu_sequential_2016 ArticleInAPeriodical 2016 November npj Computational Materials 2 1 http://www.nature.com/articles/npjcompumats201516 https://doi.org/10.1038/npjcompumats.2015.16 15016 XuShuozhi XiongLiming ChenYouping McDowellDavidL Sequential slip transfer of mixed-character dislocations across Σ3 coherent twin boundary in FCC metals: a concurrent atomistic-continuum study Three-dimensional modelling has uncovered important mechanistic clues to strengthening polycrystalline metals through plastic deformation. A team led by David McDowell at the Georgia Institute of Technology in the US used concurrent atomistic-continuum (CAC) simulations to investigate the challenging problem of how curved dislocations pile-up and interact with special ‘twin’ grain boundaries in copper and aluminum when the metals are subjected to mechanical strain. These line defects move until they meet barriers such as grain boundaries separating crystalline regions, where they ‘pile-up’ behind the leading defect and may inhibit further defects from forming, a process known as work hardening. The multiscale CAC technique coarse grains the lattice using 3-D rhombohedra, and then applies an integral form finite element method to describe dislocation motion between elements, critical for understanding work hardening. xu_shear_2017 ArticleInAPeriodical 2017 Acta Materialia 122 https://doi.org/10.1016/j.actamat.2016.10.005 412-419 XuShuozhi XiongLiming ChenYouping McDowellDavidL Shear stress- and line length-dependent screw dislocation cross-slip in FCC Ni Screw dislocation cross-slip is important in dynamic recovery of deformed metals. A mobile screw dislocation segment can cross slip to annihilate an immobile screw dislocation segment with opposite Burgers vector, leaving excess dislocations of one kind in a crystal. Previous studies have found that the cross-slip process depends on both the local stress state and dislocation line length, yet a quantitative study of the combined effects of these two factors has not been conducted. In this work, we employ both dynamic concurrent atomistic-continuum (CAC) [L. Xiong, G. Tucker, D.L. McDowell, Y. Chen, J. Mech. Phys. Solids 59 (2011) 160???177] and molecular dynamics simulations to explore the shear stress- and line length-dependent screw dislocation cross-slip in face-centered cubic Ni. It is demonstrated that the CAC approach can accurately describe the 3-D cross-slip process at a significantly reduced computational cost, as a complement to other numerical methods. In particular, we show that the Fleischer (FL) [R.L. Fleischer, Acta Metall. 7 (1959) 134???135] type cross-slip, in which a stair-rod dislocation is involved, can be simulated in the coarse-grained domain. Our simulations show that as the applied shear stress increases, the cross-slip mechanism changes from the Friedel-Escaig (FE) [B. Escaig, J. Phys. 29 (1968) 225???239] type to the FL type. In addition, the critical shear stress for both cross-slip mechanisms depends on the dislocation line length. Moreover, the cross-slip of a screw dislocation with a length of 6.47??nm analyzed using periodic boundary conditions occurs via only the FL mechanism, whereas a longer dislocation with length of 12.94??nm can cross-slip via either the FE or FL process in Ni subject to different shear stresses. xu_size-dependent_2017 ArticleInAPeriodical 2017 May Journal of Applied Physics 121 17 http://aip.scitation.org/doi/10.1063/1.4982754 https://doi.org/10.1063/1.4982754 175101 XuShuozhi StarttJacobK PayneThomasG DeoChaitanyaS McDowellDavidL Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten Compared with face-centered cubic metals, twinned nanopillars in body-centered cubic (BCC) systems are much less explored partly due to the more complicated plastic deformation behavior and a lack of reliable interatomic potentials for the latter. In this paper, the fault energies predicted by two semi-empirical interatomic potentials in BCC tungsten (W) are first benchmarked against density functional theory calculations. Then, the more accurate potential is employed in large scale molecular dynamics simulations of tensile and compressive loading of twinned nanopillars in BCC W with different cross sectional shapes and sizes. A single crystal, a twinned crystal, and single crystalline nanopillars are also studied as references. Analyses of the stress-strain response and defect nucleation reveal a strong tension-compression asymmetry and a weak pillar size dependence in the yield strength. Under both tensile and compressive loading, plastic deformation in the twinned nanopillars is dominated by dislocatio... Yang_2015 ArticleInAPeriodical The Royal Society 2015 mar ConferenceProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471 2175 https://doi.org/10.1098%2Frspa.2014.0758 20140758 YangShengfeng ChenYouping Concurrent atomistic and continuum simulation of bi-crystal strontium titanate with tilt grain boundary Yang_2020a ArticleInAPeriodical Elsevier BV 2020 mar International Journal of Plasticity 126 https://doi.org/10.1016%2Fj.ijplas.2019.09.016 102610 YangHui ZhuLinggang ZhangRuifeng ZhouJian SunZhimei Influence of high stacking-fault energy on the dissociation mechanisms of misfit dislocations at semi-coherent interfaces Yang_2020 ArticleInAPeriodical Elsevier BV 2020 jan Materials & Design 186 https://doi.org/10.1016%2Fj.matdes.2019.108294 108294 YangHui ZhuLinggang ZhangRuifeng ZhouJian SunZhimei Shearing dominated by the coupling of the interfacial misfit and atomic bonding at the FCC (111) semi-coherent interfaces yang_concurrent_2013 ArticleInAPeriodical 2013 Acta Materialia 61 1 https://doi.org/10.1016/j.actamat.2012.09.032 89-102 YangShengfeng XiongLiming DengQian ChenYouping Concurrent atomistic and continuum simulation of strontium titanate This paper presents a concurrent atomistic-continuum methodology (CAC) to simulate the dynamic processes of dislocation nucleation and migration as well as crack initiation and propagation in complex crystals. The accuracy and efficiency of the method is tested with respect to the molecular dynamics (MD) method through simulations of the dynamic fracture processes in strontium titanate under a combination of tension and shear loading and the dislocation behavior under nanoindentation. CAC simulation results demonstrated a smooth passage of cracks and dislocations through the atomistic-continuum interface without the need for additional constitutive rules or special numerical treatment. Although some accuracy is lost in CAC simulations as a consequence of a 98.4% reduction in the degrees of freedom, all the CAC results are qualitatively and quantitatively comparable with MD results. The stacking fault width and nanoindentation hardness measured in the CAC simulations agrees well with existing experimental data. Criteria for cleavage and slip in ionic materials are verified. The need to include the internal degrees of freedom of atoms in concurrent atomistic-continuum methods for polyatomic crystalline materials is confirmed. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. yang_concurrent_2016 BookSection Springer Vol. 245 2016 Multiscale Materials Modeling for Nanomechanics‘ 261-296 YangShengfeng ChenYouping Concurrent Atomistic-Continuum Simulation of Defects in Polyatomic Ionic Materials Yao_2020 ArticleInAPeriodical Elsevier BV 2020 feb Computer Physics Communications 247 https://doi.org/10.1016%2Fj.cpc.2019.07.020 106857 YaoBN ZhangRF AADIS: An atomistic analyzer for dislocation character and distribution Yin_2019 ArticleInAPeriodical AIP Publishing 2019 jan Journal of Applied Physics 125 2 https://doi.org/10.1063%2F1.5055901 025112 YinFuxing ZhaoYizhe YuSiyuan PangWeiwei Molecular dynamics studies on the interface evolution characteristics and deformation mechanisms of Cu/Al multilayers during compression process Youngs_2009 ArticleInAPeriodical Wiley 2009 Journal of Computational Chemistry https://doi.org/10.1002%2Fjcc.21359 NA-NA YoungsTGA Aten-An application for the creation, editing, and visualization of coordinates for glasses, liquids, crystals, and molecules yuan_molecular_2007 ArticleInAPeriodical 2007 April Journal of Materials Processing Technology 184 1-3 https://www.sciencedirect.com/science/article/pii/S0924013606009022 https://doi.org/10.1016/J.JMATPROTEC.2006.10.042 1-5 YuanLin ShanDebin GuoBin Molecular dynamics simulation of tensile deformation of nano-single crystal aluminum In order to research the mechanisms of tensile deformation at nanometer, molecular dynamics (MD) was employed to simulate the tension process of nano-single crystal aluminum (Al) under different temperatures. The results show that the stress–strain curves decrease after a linear increase up to the maximum abruptly because the first transition from elastic to plastic deformation and the slip take place. Then the multiple slips on the (111) planes continue to occur after the yield. At last, the plastic deformation causes ductile shear fracture. Atomistic simulations of tension at nanometer give results that agree with the phenomenological attributes of plasticity observed in macroscale experiments. The lower strain rate results in the lower yield stress. The tensile strength decreases at higher temperatures. yu_strengthening_2013 ArticleInAPeriodical 2013 December Surface and Coatings Technology 237 https://www.sciencedirect.com/science/article/pii/S0257897213005483 https://doi.org/10.1016/J.SURFCOAT.2013.05.051 269-275 YuKY LiuY RiosS WangH ZhangX Strengthening mechanisms of Ag/Ni immiscible multilayers with fcc/fcc interface We investigate the microstructure and mechanical properties of sputtered face-centered cubic (fcc) Ag/Ni multilayers with varying individual layer thickness h of 1–200 nm deposited on Si (100) and Si (111) substrates. Both multilayer systems have similar \textbackslashtextless111\textbackslashtextgreater fiber texture with predominantly incoherent Ag/Ni interfaces. Superlattice structure arises when h decreases to less than 5nm. Indentation hardness of both Ag/Ni systems shows similar significant size dependence when h \textbackslashtextgreater 3nm. Strengthening mechanisms in Ag/Ni systems are discussed and compared to those in Cu/Ni and Ag/Cu systems with fcc/fcc interfaces. Zbib_2012 ArticleInAPeriodical AIP Publishing 2012 aug Journal of Applied Physics 112 4 https://doi.org/10.1063%2F1.4748149 044307 ZbibHM MastorakosIN BahrDF Deformation mechanisms, size effects, and strain hardening in nanoscale metallic multilayers under nanoindentation zeng_high_2016 ArticleInAPeriodical 2016 May Acta Materialia 110 https://www.sciencedirect.com/science/article/pii/S1359645416301872 https://doi.org/10.1016/J.ACTAMAT.2016.03.034 341-351 ZengLF GaoR FangQF WangXP XieZM MiaoS HaoT ZhangT High strength and thermal stability of bulk Cu/Ta nanolamellar multilayers fabricated by cross accumulative roll bonding Bulk Cu/Ta nanolamellar multilayers with an individual layer thickness from several micrometers down to 50 nm were successfully fabricated via a combination of cross accumulative roll bonding (CARB) and an intermediate annealing step. This fabrication technique allowed to effectively suppress the formation of plastic instabilities and edge cracks during the repeated rolling process. A transition of the layered morphology from non-planar interfaces at the submicron level to nearly planar interfaces at the nano-scale was observed with decreasing layer thickness. High resolution transmission electron microscopy, selected area electron diffraction and X-ray diffraction were performed, and the results indicate that the Cu/Ta nanolamellar multilayers with a layer thickness of 50 nm show a {100}Ta[110]∥{110}Cu[111] rolling texture relationship. Tensile tests revealed that the ultimate tensile strength of the composite was up to 950 MPa, which is approximately 5 times higher than that of the initial pure Cu and Ta. The hardness of the prepared multilayer maintained unchanged even after an annealing at 500 °C for 1 h. These unique properties are attributed to an atomically flat bimetal interface and the low amount of homophase grain boundaries resulted from the CARB process. Zhang_2014 ArticleInAPeriodical Elsevier BV 2014 oct Acta Materialia 79 https://doi.org/10.1016%2Fj.actamat.2014.07.016 74-83 ZhangRF GermannTC LiuX.-Y. WangJ BeyerleinIJ Layer size effect on the shock compression behavior of fcc–bcc nanolaminates zhang_length-scale-dependent_2011 ArticleInAPeriodical 2011 Acta Materialia 59 19 https://doi.org/10.1016/j.actamat.2011.08.016 7368-7379 ZhangJY ZhangX WangRH LeiSY ZhangP NiuJJ LiuG ZhangGJ SunJ Length-scale-dependent deformation and fracture behavior of Cu/X (X = Nb, Zr) multilayers: The constraining effects of the ductile phase on the brittle phase The plastic deformation and fracture behavior of two different types of Cu/X (X = Nb, Zr) nanostructured multilayered films (NMFs) were systematically investigated over wide ranges of modulation period (λ) and modulation ratio (η, the ratio of X layer thickness to Cu layer thickness). It was found that both the ductility and fracture mode of the NMFs were predominantly related to the constraining effect of ductile Cu layers on microcrack-initiating X layers, which showed a significant length-scale dependence on λ and η. Experimental observations and theoretical analyses also revealed a transition in strengthening mechanism, from single dislocation slip in confined layers to a load-bearing effect, when the Cu layer thickness was reduced to below ∼15 nm by either decreasing λ or increasing η. This is due to the intense suppression of dislocation activities in the thin Cu layers, which causes a remarkable reduction in the deformability of the Cu layers. Concomitantly, the constraining effect of Cu layers on microcrack propagation is weakened, which can be used to explain the experimentally observed λ and η-dependent fracture mode transition from shear mode to an opening mode. Furthermore, the fracture toughness of the NMFs is also found to be sensitive to both λ and η. A fracture mechanism-based micromechanical model is developed to quantitatively assess the length-scale-dependent fracture toughness, and these calculations are in good agreement with experimental findings. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. zhang_manipulating_2016 ArticleInAPeriodical 2016 July Acta Materialia 113 https://www.sciencedirect.com/science/article/pii/S1359645416303536 https://doi.org/10.1016/J.ACTAMAT.2016.05.015 194-205 ZhangRF BeyerleinIJ ZhengSJ ZhangSH StukowskiA GermannTC Manipulating dislocation nucleation and shear resistance of bimetal interfaces by atomic steps By means of atomistic simulations and interface dislocation theory, the mechanism of dislocation nucleation and shear resistance of various stepped fcc/bcc interfaces are comparatively studied using the Kurdjumov-Sachs (KS) Cu/Nb interface as a prototype. It is found that the introduction of atomic steps at the flat Cu{111}/{110}Nb KS interface does not change the most preferred slip systems, but influences the nucleation sites at the interface during tension loading, indicating that the flat and stepped interfaces possesses comparable energetic barriers for dislocation nucleation. During shear loading, the steps may significantly enhance the resistance to interface sliding by propagating partial dislocations that facilitate the emission and growth of parallel twins via cross slip. When the parallel twins are not favored or are hindered, the interface sliding will dominate in a “climbing peak-to-valley” manner. These results provide an effective pathway to solve the trade-off dilemma between dislocation nucleation and interface sliding by appropriately manipulating atomic steps at the flat interface in the design of high-strength metallic materials. zhang_modulation_2015 ArticleInAPeriodical 2015 June Materials Science and Engineering: A 636 https://www.sciencedirect.com/science/article/pii/S0921509315003263 https://doi.org/10.1016/J.MSEA.2015.03.075 216-220 ZhangB KouY XiaYY ZhangX Modulation of strength and plasticity of multiscale Ni/Cu laminated composites The multiscale Ni/Cu laminated composites with different layer-thickness ratios and grain sizes were designed and prepared by the dual-bath electrodeposition technique. Strength and ductility of the multiscale Ni/Cu laminated composites were investigated by tensile tests at room temperature. The experimental results show that the ultrafine-grained Ni/coarse-grained Cu laminated composites with a thickness ratio of 20:1 have a good synergy of strength and ductility. For this Ni/Cu laminated composite, not only could the large strain hardening ability and the good plastic deformation stability of the thick ultrafine-grained Ni layers be obtained, but also the ductility of the ultrathin coarse-grained Cu layers and the resistance to the development of strain localization of the ultrafine-grained Ni layers did not become degraded. Basic mechanisms for optimizing the strength and the ductility in the multiscale Ni/Cu laminated composites are discussed. zhang_review_2016 ArticleInAPeriodical 2016 Computational Materials Science 118 https://doi.org/10.1016/j.commatsci.2016.03.021 180-191 ZhangLiang LuCheng TieuKiet A review on atomistic simulation of grain boundary behaviors in face-centered cubic metals Grain boundaries are the interfaces between differently oriented crystals of the same material. The underlying structures of grain boundary play a significant role in mechanical properties of polycrystalline materials. This influence becomes more significant when the grain size is reduced to ultrafine or nano size scale where the dislocation activities in the interior of grains lessen and mechanisms mediated by the grain boundary become dominant. This paper reviewed recent results in the atomistic simulation of the nanoscale behavior of grain boundary in face-centered cubic (fcc) metals. Three different simulation models were introduced to investigate the grain boundary behavior during plastic deformation, including three-dimensional (3D) nanocrystalline model, columnar nanocrystalline model and bicrystal model. The grain boundary was found to contribute to plastic deformation through the process of dislocation absorption, transmission or nucleation at boundary plane, as well as grain boundary accommodation mechanisms such as GB sliding and GB migration. These grain boundary mediated mechanisms were widely studied by the previous atomistic simulation works and were extensively reviewed here. Future challenges and directions in the computational study of grain boundary behaviors were also discussed. zhang_stress-assisted_2017 ArticleInAPeriodical 2017 Acta Materialia 131 https://doi.org/10.1016/j.actamat.2017.03.060 39-47 ZhangYang TuckerGarrittJ TrelewiczJasonR Stress-assisted grain growth in nanocrystalline metals: Grain boundary mediated mechanisms and stabilization through alloying The mechanisms of stress-assisted grain growth are explored using molecular dynamics simulations of nanoindentation in nanocrystalline Ni and Ni-1 at.% P as a function of grain size and deformation temperature. Grain coalescence is primarily confined to the high stress region beneath the simulated indentation zone in nanocrystalline Ni with a grain size of 3 nm. Grain orientation and atomic displacement vector mapping demonstrates that coalescence transpires through grain rotation and grain boundary migration, which are manifested in the grain interior and grain boundary components of the average microrotation. A doubling of the grain size to 6 nm and addition of 1 at.% P eliminates stress-assisted grain growth in Ni. In the absence of grain coalescence, deformation is accommodated by grain boundary-mediated dislocation plasticity and thermally activated in pure nanocrystalline Ni. By adding solute to the grain boundaries, the temperature-dependent deformation behavior observed in both the lattice and grain boundaries inverts, indicating that the individual processes of dislocation and grain boundary plasticity will exhibit different activity based on boundary chemistry and deformation temperature. zhang_universal_2016 ArticleInAPeriodical 2016 Advanced Science and Technology Letters 121 Ast 63-67 ZhangYuting LiYujie DingXiuli Universal Format of Shape Function for Numerical Analysis using Multiple Element Forms Universal Format of Shape Function using Linear Hexahedron Zheng_2015 ArticleInAPeriodical Springer Science and Business Media LLC 2015 oct Scientific Reports 5 1 https://doi.org/10.1038%2Fsrep15428 ZhengShijian ShaoShuai ZhangJian WangYongqiang DemkowiczMichaelJ BeyerleinIreneJ MaraNathanA Adhesion of voids to bimetal interfaces with non-uniform energies zherebtsov_loss_2010 ArticleInAPeriodical 2010 Philosophical Magazine Letters 90 12 https://doi.org/10.1080/09500839.2010.521526 903-914 ZherebtsovSergey SalishchevGennady Lee SemiatinS Loss of coherency of the alpha/beta interface boundary in titanium alloys during deformation The loss of coherency of interphase boundaries in two-phase titanium alloys during deformation was analyzed. The energy of the undeformed interphase boundary was first determined by means of the van der Merwe model for stepped interfaces. The subsequent loss of coherency was ascribed to the increase of interphase energy due to absorption of lattice dislocations and was quantified by a relation similar to the Read-Shockley equation for low-angle boundaries in single-phase alloys. It was found that interphase boundaries lose their coherency by a strain of approximately 0.5 at T=800$\textbackslashbackslash$,⌃{$\textbackslashbackslash$circ}C. zhigilei_introduction_2013 ArticleInAPeriodical 2013 None I ZhigileiLeonid Introduction to interatomic potentials (I) In order to use Molecular Dynamics or Monte Carlo methods we have to define the rules that are governing interaction of atoms in the system. In classical and semi-classical simulations these rules are often expressed in terms of potential functions. The potential function U(r 1 , r 2 , \textbackslashldots, r N) describes how the potential energy of a system of N atoms depends on the coordinates of the atoms, r 1 , r 2 , \textbackslashldots, r N . It is assumed the electrons adjust to new atomic positions much faster than the motion of the atomic nuclei (Born-Oppenheimer approximation). The forces in MD simulation are defined by the potential, How to obtain the potential function for a particular system? Introduction to interatomic potentials (I) Zhou_1999 ArticleInAPeriodical Elsevier BV 1999 jul Acta Materialia 47 9 https://doi.org/10.1016%2Fs1359-6454%2899%2900127-5 2695-2703 ZhouSJ PrestonDL LouchetF Investigation of vacancy formation by a jogged dissociated dislocation with large-scale molecular dynamics and dislocation energetics Zhou_2018 ArticleInAPeriodical MDPI AG 2018 oct Applied Sciences 8 10 https://doi.org/10.3390%2Fapp8101821 1821 ZhouQing RenYue DuYin HuaDongpeng HanWeichao Cracking and Toughening Mechanisms in Nanoscale Metallic Multilayer Films: A Brief Review zhou_mechanical_2015 ArticleInAPeriodical 2015 June Acta Mechanica Sinica 31 3 http://link.springer.com/10.1007/s10409-015-0401-1 https://doi.org/10.1007/s10409-015-0401-1 319-337 ZhouQ XieJY WangF HuangP XuKW LuTJ The mechanical behavior of nanoscale metallic multilayers: A survey zhou_new_2003 ArticleInAPeriodical 2003 September ConferenceProceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 459 2037 http://www.royalsocietypublishing.org/doi/10.1098/rspa.2003.1127 https://doi.org/10.1098/rspa.2003.1127 2347-2392 ZhouMin A new look at the atomic level virial stress: on continuum-molecular system equivalence Zhu_2020 ArticleInAPeriodical Informa UK Limited 2020 sep Materials Research Letters 9 1 https://doi.org/10.1080%2F21663831.2020.1796836 1-31 ZhuYuntian AmeyamaKei AndersonPeterM BeyerleinIreneJ GaoHuajian KimHyoungSeop LaverniaEnrique MathaudhuSuveen MughrabiHael RitchieRobertO TsujiNobuhiro ZhangXiangyi WuXiaolei Heterostructured materials: superior properties from hetero-zone interaction zhu_scale-dependent_2010 ArticleInAPeriodical 2010 June Philosophical Magazine Letters 90 6 http://www.tandfonline.com/doi/abs/10.1080/09500831003745241 https://doi.org/10.1080/09500831003745241 413-421 ZhuXF ZhangGP YanC ZhuSJ SunJ Scale-dependent fracture mode in Cu–Ni laminate composites Fracture behavior of Cu–Ni laminate composites has been investigated by tensile testing. It was found that as the individual layer thickness decreases from 100 to 20 nm, the resultant fracture angle of the Cu–Ni laminate changes from 72° to 50°. Cross-sectional observations reveal that the fracture of the Ni layers transforms from opening to shear mode as the layer thickness decreases while that of the Cu layers keeps shear mode. Competition mechanisms were proposed to understand the variation in fracture mode of the metallic laminate composites associated with length scale. zhu_tensile_2009 ArticleInAPeriodical 2009 March Journal of Physics D: Applied Physics 42 5 http://stacks.iop.org/0022-3727/42/i=5/a=055411?key=crossref.54e50de0d666f101a811f503d3278c4c https://doi.org/10.1088/0022-3727/42/5/055411 055411 ZhuXF ZhangGP Tensile and fatigue properties of ultrafine Cu–Ni multilayers Zimmerman_2001 ArticleInAPeriodical American Physical Society (APS) 2001 oct Physical Review Letters 87 16 https://doi.org/10.1103%2Fphysrevlett.87.165507 ZimmermanJA KelchnerCL KleinPA HamiltonJC FoilesSM Surface Step Effects on Nanoindentation Zimmerman_2009 ArticleInAPeriodical Elsevier BV 2009 jan International Journal of Solids and Structures 46 2 https://doi.org/10.1016%2Fj.ijsolstr.2008.08.036 238-253 ZimmermanJonathanA BammannDouglasJ GaoHuajian Deformation gradients for continuum mechanical analysis of atomistic simulations