author = {Adhika, Damar Rastri and Tanaka, Masaki and Daio, Takeshi and Higashida, Kenji},
title = {Crack tip shielding observed with high-resolution transmission electron microscopy},
journal = {Microscopy},
year = {2015},
number = {5},
volume = {64},
pages = {335--340},
doi = {10.1093/jmicro/dfv032},
file = {/home/aselimov/docs/My Library/files/699/Adhika et al. - 2015 - Crack tip shielding observed with high-resolution transmission electron microscopy(2).pdf},
abstract = {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 ...},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/652/Andric, Curtin - 2017 - New theory for Mode I crack-tip dislocation emission(2).pdf},
file = {/home/aselimov/docs/My Library/files/852/Influence of crystallographic orientation and layer thickness on fracture behavior of Ni-Ni3Al films.pdf},
issn = {13596462}
}
@article{banerjee_perspectives_2013,
author = {Banerjee, Dipankar and Williams, J. C.},
title = {Perspectives on titanium science and technology},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/841/Baskes, Johnson - 1994 - Modified embedded atom potentials for HCP metals(2).pdf},
issn = {0965-0393},
pmid = {16413049}
}
@article{belytschko_review_2009,
author = {Belytschko, Ted and Gracie, Robert and Ventura, Giulio},
title = {A review of extended/generalized finite element methods for material modeling},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/849/Belytschko, Gracie, Ventura - 2009 - A review of extendedgeneralized finite element methods for material modeling(2).pdf},
issn = {0965-0393},
pmid = {266373500001}
}
@article{berendsen_molecular_1984,
author = {Berendsen, H. J. C. and Postma, J. P. M. and van Gunsteren, W. F. and DiNola, A. and Haak, J. R.},
title = {Molecular dynamics with coupling to an external bath},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/864/Berendsen et al. - 1984 - Molecular dynamics with coupling to an external bath.pdf},
abstract = {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.},
abstract = {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 {\textbackslash}textgreater 12), elevated temperatures ({\textbackslash}textgreater 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.},
file = {/home/aselimov/docs/My Library/files/877/Emergence of stable interfaces under extreme plastic deformation.pdf},
issn = {0027-8424},
pmid = {24616514}
}
@article{bhattacharyya_transmission_2009,
author = {Bhattacharyya, D. and Mara, N.A. and Dickerson, P. and Hoagland, R.G. and Misra, A.},
title = {Transmission electron microscopy study of the deformation behavior of Cu/Nb and Cu/Ni nanoscale multilayers during nanoindentation},
abstract = {\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},
file = {/home/aselimov/docs/My Library/files/867/Bhattacharyya et al. - 2009 - Transmission electron microscopy study of the deformation behavior of CuNb and CuNi nanoscale multilayers.pdf},
issn = {0884-2914},
keyword = {Nanoindentation, Nanoscale, Transmission electron microscopy (TEM)}
author = {Bitzek, Erik and Kermode, James R. and Gumbsch, Peter},
title = {Atomistic aspects of fracture},
journal = {International Journal of Fracture},
year = {2015},
number = {1-2},
volume = {191},
pages = {13--30},
doi = {10.1007/s10704-015-9988-2},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/848/Bollmann - 1972 - The basic concepts of the 0-lattice theory.pdf},
issn = {00396028}
}
@article{britton_mechanistic_2015,
author = {Britton, TB and Dunne, FPE and Wilkinson, AJ},
title = {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},
journal = {Proc. R. Soc. A},
year = {2015},
volume = {471},
pages = {20140881},
doi = {10.1098/rspa.2014.0881},
file = {/home/aselimov/docs/My Library/files/628/Britton, Dunne, Wilkinson - 2015 - On the mechanistic basis of deformation at the microscale in hexagonal close-packed metals On the mec.pdf},
file = {/home/aselimov/docs/My Library/files/723/Caputo, Lamanna, Soprano - 2013 - On the evaluation of the plastic zone size at the crack tip(2).pdf},
issn = {00137944},
keyword = {EPFM, Plastic zone size, Short cracks}
}
@article{carlton_what_2007,
author = {Carlton, C. E. and Ferreira, P. J.},
title = {What is behind the inverse {Hall}-{Petch} effect in nanocrystalline materials?},
title = {Atomistic formulation of a multiscale field theory for nano/micro solids},
journal = {Philosophical Magazine},
year = {2005},
number = {33-35},
volume = {85},
pages = {4095--4126},
doi = {10.1080/14786430500362595},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/686/Chen, Lee - 2005 - Atomistic formulation of a multiscale field theory for nanomicro solids(3).pdf},
issn = {14786435}
}
@article{cheng_misfit_2007,
author = {Cheng, Dong and Yan, Zhi Jun and Yan, Li},
title = {Misfit dislocation network in Cu/Ni multilayers and its behaviors during scratching},
abstract = {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.},
file = {Attachment:files/827/Cheng, Yan, Yan - 2007 - Misfit dislocation network in CuNi multilayers and its behaviors during scratching.pdf:application/pdf},
issn = {0040-6090}
}
@article{chetty_stacking_1997,
author = {Chetty, N. and Weinert, M.},
title = {Stacking faults in magnesium},
journal = {Physical Review B - Condensed Matter and Materials Physics},
year = {1997},
number = {17},
volume = {56},
pages = {10844--10851},
doi = {10.1103/PhysRevB.56.10844},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/677/Cheung et al. - 2008 - Computer simulation of liquids and liquid crystals(2).pdf},
isbn = {0-19-855645-4},
keyword = {Bridge function, Integral equations, Molecular simulation, Monte Carlo},
pmid = {2699618}
}
@article{cho_toward_2015,
author = {Cho, Jaehyun and Junge, Till and Molinari, Jean-françois and Anciaux, Guillaume},
title = {Toward a {3D} coupled atomistic and discrete dislocation dynamics simulation : dislocation core structures and {Peierls} stresses with several character angles in {FCC} aluminum},
journal = {Advanced Modeling and Simulation in Engineering Sciences},
file = {/home/aselimov/docs/My Library/files/874/Cho et al. - 2015 - Toward a 3D coupled atomistic and discrete dislocation dynamics simulation dislocation core structures and Peierls s.pdf},
abstract = {{\textbackslash}textlessp{\textbackslash}textgreater 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 {\textbackslash}textlesssup{\textbackslash}textgreater6{\textbackslash}textless/sup{\textbackslash}textgreater mm/mm {\textbackslash}textlesssup{\textbackslash}textgreater3{\textbackslash}textless/sup{\textbackslash}textgreater , 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 {\textbackslash}textlesssup{\textbackslash}textgreater2{\textbackslash}textless/sup{\textbackslash}textgreater . 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. {\textbackslash}textless/p{\textbackslash}textgreater},
file = {/home/aselimov/docs/My Library/files/840/Clemens, Kung, Barnett - 1999 - Structure and Strength of Multilayers.pdf},
issn = {0883-7694}
}
@article{Couret_1993,
author = {Couret, A. and Crestou, J. and Farenc, S. and Molenat, G. and Clement, N. and Coujou, A. and Caillard, D.},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/615/Cui - 2017 - The Investigation of Plastic Behavior by Discrete Dislocation Dynamics for Single Crystal Pillar at Submicron Scale.pdf},
isbn = {978-3-642-35132-7},
keyword = {icle},
pmid = {25246403}
}
@article{Damadam_2017,
author = {Damadam, Mohsen and Shao, Shuai and Ayoub, Georges and Zbib, Hussein M.},
title = {Recent advances in modeling of interfaces and mechanical behavior of multilayer metallic/ceramic composites},
journal = {Journal of Materials Science},
publisher = {Springer Science and Business Media LLC},
title = {Embedded-atom method: {Derivation} and application to impurities, surfaces, and other defects in metals},
journal = {Physical Review B},
year = {1984},
number = {12},
volume = {29},
pages = {6443--6453},
doi = {10.1103/PhysRevB.29.6443},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/708/Daw, Baskes - 1984 - Embedded-atom method Derivation and application to impurities, surfaces, and other defects in metals(4).pdf},
issn = {01631829},
pmid = {21688283}
}
@article{dehm_overview_2018,
author = {Dehm, G. and Jaya, B. N. and Raghavan, R. and Kirchlechner, C.},
title = {Overview on micro- and nanomechanical testing: {New} insights in interface plasticity and fracture at small length scales},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/621/Overview on micro- and nanomechanical testing.pdf},
title = {Structure, shear resistance and interaction with point defects of interfaces in Cu–Nb nanocomposites synthesized by severe plastic deformation},
title = {A {Coarse}-grained atomistic method for {3D} dynamic fracture simulation},
journal = {International Journal for Multiscale Computational Engineering},
year = {2013},
number = {3},
volume = {11},
pages = {227--237},
doi = {10.1615/IntJMultCompEng.2013005442},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/682/Deng, Chen - 2013 - A Coarse-grained atomistic method for 3D dynamic fracture simulation(2).pdf},
author = {Diard, O. and Leclercq, S. and Rousselier, G. and Cailletaud, G.},
title = {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},
file = {/home/aselimov/docs/My Library/files/870/Diard et al. - 2005 - Evaluation of finite element based analysis of 3D multicrystalline aggregates plasticity Application to crystal(2).pdf},
author = {Ding, Zhigang and Li, Shuang and Liu, Wei and Zhao, Yonghao},
title = {Modeling of {Stacking} {Fault} {Energy} in {Hexagonal}-{Close}-{Packed} {Metals}},
journal = {Advances in Materials Science and Engineering},
year = {2015},
number = {May},
volume = {2015},
doi = {10.1155/2015/639519},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/631/Ding et al. - 2015 - Modeling of Stacking Fault Energy in Hexagonal-Close-Packed Metals.pdf},
author = {Dupraz, Maxime and Rao, Satish I. and Swygenhoven, Helena Van},
title = {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},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/721/Eslami, Zebarjad, Moshksar - 2013 - Study on mechanical and magnetic properties of CuNi multilayer composite fabricated by accumulative.pdf},
issn = {0267-0836},
keyword = {Accumulative roll bonding, Copper/nickel composites, Layered structures, Magnetic and mechanical properties}
}
@article{Evans_1985,
author = {Evans, D. J. and Holian, B. L.},
title = {The Nose–Hoover thermostat},
journal = {The Journal of Chemical Physics},
publisher = {AIP Publishing},
year = {1985},
month = {oct},
number = {8},
volume = {83},
pages = {4069--4074},
url = {https://doi.org/10.1063%2F1.449071},
doi = {10.1063/1.449071}
}
@article{Faken_1994,
author = {Faken, Daniel and Jónsson, Hannes},
title = {Systematic analysis of local atomic structure combined with 3D computer graphics},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/664/Fan, Stewart, Xu - 2017 - Simulation accuracy of crack-tip parameters with extended GP methods(2).pdf},
title = {Interatomic potentials for {Ti}-{Al} with and without angular forces},
journal = {Modelling and Simulation in Materials Science and Engineering},
year = {1994},
volume = {2},
pages = {975},
file = {/home/aselimov/docs/My Library/files/881/Farkas, Jones - 1994 - Modelling and Simulation in Materials Science and Engineering Related content Interatomic potentials for Ti-Al(2).pdf}
}
@article{farkas_modelling_1994,
author = {Farkas, Diana and Jones, Chris},
title = {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},
year = {1994},
file = {/home/aselimov/docs/My Library/files/643/Farkas, Jones - 1994 - Modelling and Simulation in Materials Science and Engineering Related content Interatomic potentials for Ti-Al(2).pdf}
}
@article{feyel_multilevel_2003,
author = {Feyel, Fr??d??ric},
title = {A multilevel finite element method ({FE2}) to describe the response of highly non-linear structures using generalized continua},
journal = {Computer Methods in Applied Mechanics and Engineering},
year = {2003},
number = {28-30},
volume = {192},
pages = {3233--3244},
doi = {10.1016/S0045-7825(03)00348-7},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/835/Feyel - 2003 - A multilevel finite element method (FE2) to describe the response of highly non-linear structures using generalized co(2).pdf},
author = {Foiles, S. M. and Baskes, M. I. and Daw, M. S.},
title = {Embedded-atom-method functions for the fcc metals {Cu}, {Ag}, {Au}, {Ni}, {Pd}, {Pt}, and their alloys},
journal = {Physical Review B},
year = {1986},
number = {12},
volume = {33},
pages = {7983--7991},
doi = {10.1103/PhysRevB.33.7983},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/715/Foiles, Baskes, Daw - 1986 - Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys.pdf},
issn = {01631829},
pmid = {9938188}
}
@article{Franca_1989,
author = {Franca, L. P.},
title = {An algorithm to compute the square root of a 3 × 3 positive definite matrix},
journal = {Computers \& Mathematics with Applications},
author = {Fu, Tao and Peng, Xianghe and Chen, Xiang and Weng, Shayuan and Hu, Ning and Li, Qibin and Wang, Zhongchang},
title = {Molecular dynamics simulation of nanoindentation on Cu/Ni nanotwinned multilayer films using a spherical indenter},
journal = {Scientific Reports},
year = {2016},
month = {December},
number = {1},
volume = {6},
pages = {35665},
url = {http://www.nature.com/articles/srep35665},
doi = {10.1038/srep35665},
abstract = {Molecular dynamics simulation of nanoindentation on Cu/Ni nanotwinned multilayer films using a spherical indenter},
file = {/home/aselimov/docs/My Library/files/833/Fu et al. - 2016 - Molecular dynamics simulation of nanoindentation on CuNi nanotwinned multilayer films using a spherical indenter(2).pdf},
issn = {2045-2322},
keyword = {Atomic and molecular physics, dimensional materials, Two}
}
@article{furuhara_computer_1991,
author = {Furuhara, T. and Aaronson, H. I.},
title = {Computer modeling of partially coherent {B}.{C}.{C}.:{H}.{C}.{P}. boundaries},
journal = {Acta Metallurgica Et Materialia},
year = {1991},
number = {11},
volume = {39},
pages = {2857--2872},
doi = {10.1016/0956-7151(91)90103-8},
abstract = {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.},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/651/Gang, ChuanJie, Peng - 2017 - The role of interface in uniaxial tensile process of nano-scale bilayer CuNi.pdf},
author = {Glaessgen, E H and Saether, E and Hochhalter, J D and Yamakov, V},
title = {Modeling {Near}-{Crack}-{Tip} {Plasticity} {From} {Nano}- to {Micro}-{Scales}},
journal = {51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference},
year = {2010},
pages = {1--21},
abstract = {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},
file = {/home/aselimov/docs/My Library/files/659/Glaessgen et al. - 2010 - Modeling Near-Crack-Tip Plasticity From Nano- to Micro-Scales(2).pdf}
}
@article{gracie_adaptive_2011,
author = {Gracie, Robert and Belytschko, Ted},
title = {An adaptive concurrent multiscale method for the dynamic simulation of dislocations},
journal = {International Journal for Numerical Methods in Engineering},
year = {2011},
month = {April},
number = {4-5},
volume = {86},
pages = {575--597},
url = {http://doi.wiley.com/10.1002/nme.3112},
doi = {10.1002/nme.3112},
file = {/home/aselimov/docs/My Library/files/611/Gracie, Belytschko - 2011 - An adaptive concurrent multiscale method for the dynamic simulation of dislocations.pdf},
author = {Gracie, Robert and Oswald, Jay and Belytschko, Ted},
title = {On a new extended finite element method for dislocations: {Core} enrichment and nonlinear formulation},
journal = {Journal of the Mechanics and Physics of Solids},
year = {2008},
number = {1},
volume = {56},
pages = {200--214},
doi = {10.1016/j.jmps.2007.07.010},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/672/Gracie, Oswald, Belytschko - 2008 - On a new extended finite element method for dislocations Core enrichment and nonlinear formulatio(2).pdf},
title = {A molecular dynamics study of transformation toughening in the gamma {TiAl}/beta {Ti}-{V} system},
journal = {Materials Science and Engineering A},
year = {1996},
volume = {219},
pages = {109--125}
}
@article{Gu_nol__2020,
author = {Guénolé, Julien and Nöhring, Wolfram G. and Vaid, Aviral and Houllé, Frédéric and Xie, Zhuocheng and Prakash, Aruna and Bitzek, Erik},
title = {Assessment and optimization of the fast inertial relaxation engine (fire) for energy minimization in atomistic simulations and its implementation in lammps},
author = {Himanen, Lauri and Jäger, Marc O. J. and Morooka, Eiaki V. and Canova, Filippo Federici and Ranawat, Yashasvi S. and Gao, David Z. and Rinke, Patrick and Foster, Adam S.},
title = {DScribe: Library of descriptors for machine learning in materials science},
abstract = {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.},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/875/Hoagland et al. - 2002 - On the strengthening effects of interfaces in multilayer fee metallic composites.pdf},
issn = {0141-8610},
keyword = {NMM}
}
@article{hoover_large-scale_1990,
author = {Hoover, William G. and De Groot, Anthony J. and Hoover, Carol G. and Stowers, Irving F. and Kawai, Toshio and Holian, Brad Lee and Boku, Taisuke and Ihara, Sigeo and Belak, J.},
title = {Large-scale elastic-plastic indentation simulations via nonequilibrium molecular dynamics},
title = {Elastic fields and energies of a circular edge disclination and a straight screw disclination},
journal = {Journal of Applied Physics},
year = {1970},
number = {13},
volume = {41},
pages = {5175--5179},
doi = {10.1063/1.1658641},
file = {/home/aselimov/docs/My Library/files/731/Huang, Mura - 1970 - Elastic fields and energies of a circular edge disclination and a straight screw disclination.pdf},
issn = {00218979}
}
@article{Hunter_2017,
author = {Hunter, Abigail and Leu, Brandon and Beyerlein, Irene J.},
title = {A review of slip transfer: applications of mesoscale techniques},
journal = {Journal of Materials Science},
publisher = {Springer Science and Business Media LLC},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/858/Iacobellis, Behdinan - 2013 - Comparison of Concurrent Multiscale Methods in the Application of Fracture in Nickel(2).pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/630/Imrich et al. - 2014 - Differences in deformation behavior of bicrystalline Cu micropillars containing a twin boundary or a large-angle.pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/884/Kanani, Hartmaier, Janisch - 2016 - Stacking fault based analysis of shear mechanisms at interfaces in lamellar TiAl alloys.pdf},
file = {/home/aselimov/docs/My Library/files/667/Kaneko et al. - 2005 - Vickers hardness and deformation of NiCu nano-multilayers electrodeposited on copper substrates.pdf},
issn = {0022-2461}
}
@article{Kim_2014,
author = {Kim, W. K. and Luskin, M. and Perez, D. and Voter, A. F. and Tadmor, E. B.},
title = {Hyper-QC: An accelerated finite-temperature quasicontinuum method using hyperdynamics},
journal = {Journal of the Mechanics and Physics of Solids},
author = {Kim, Young Min and Lee, Byeong Joo and Baskes, M. I.},
title = {Modified embedded-atom method interatomic potentials for {Ti} and {Zr}},
journal = {Physical Review B - Condensed Matter and Materials Physics},
year = {2006},
number = {1},
volume = {74},
doi = {10.1103/PhysRevB.74.014101},
abstract = {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.},
file = {files/828/Kim, Lee, Baskes - 2006 - Modified embedded-atom method interatomic potentials for Ti and Zr(3).pdf},
issn = {10980121}
}
@article{kim_plastic_2000,
author = {Kim, H. S. and Estrin, Y. and Bush, M. B.},
title = {Plastic deformation behaviour of fine-grained materials},
journal = {Acta Materialia},
year = {2000},
number = {2},
volume = {48},
pages = {493--504},
doi = {10.1016/S1359-6454(99)00353-5},
abstract = {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.},
author = {Koyama, Motomichi and Taheri-Mousavi, Seyedeh Mohadeseh and Yan, Haoxue and Kim, Jinwoo and Cameron, Benjamin Clive and Moeini-Ardakani, Seyed Sina and Li, Ju and Tasan, Cemal Cem},
title = {Origin of micrometer-scale dislocation motion during hydrogen desorption},
journal = {Science Advances},
publisher = {American Association for the Advancement of Science (AAAS)},
year = {2020},
month = {jun},
number = {23},
volume = {6},
pages = {eaaz1187},
url = {https://doi.org/10.1126%2Fsciadv.aaz1187},
doi = {10.1126/sciadv.aaz1187}
}
@article{Kramer_2002,
author = {Kramer, D. E. and Foecke, T.},
title = {Transmission electron microscopy observations of deformation and fracture in nanolaminated Cu-Ni thin films},
title = {An {Engineering} {Approach} for {Elastic}-{Plastic} {Fracture} {Analysis}},
year = {1981},
abstract = {(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.},
file = {/home/aselimov/docs/My Library/files/843/Kumar M D German C F Shih - 1981 - An Engineering Approach for Elastic-Plastic Fracture Analysis(2).pdf},
keyword = {\_, · · c Keywords-, Fracture Han∼∼C)Qk}
}
@book{lesar_introduction_2013,
author = {Lesar, Richard},
title = {Introduction to {Computational} {Materials} {Science}: {Fundamentals} to {Applications}},
year = {2013},
url = {www.cambridge.org/9780521845878},
doi = {10.1017/CBO9781139033398},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/632/Lesar - 2013 - Introduction to Computational Materials Science Fundamentals to Applications(2).pdf},
isbn = {978-0-521-84587-8},
pmid = {25246403}
}
@article{Li_2010,
author = {Li, Nan and Wang, J. and Huang, J. Y. and Misra, A. and Zhang, X.},
title = {In situ TEM observations of room temperature dislocation climb at interfaces in nanolayered Al/Nb composites},
abstract = {{\textbackslash}textlessdiv class="abstract" data-abstract-type="normal"{\textbackslash}textgreater {\textbackslash}textlessp{\textbackslash}textgreater {\textbackslash}textlessspan class='italic'{\textbackslash}textgreaterIn situ{\textbackslash}textless/span{\textbackslash}textgreater 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.{\textbackslash}textless/p{\textbackslash}textgreater {\textbackslash}textless/div{\textbackslash}textgreater},
file = {/home/aselimov/docs/My Library/files/868/Li et al. - 2012 - Direct Observations of Confined Layer Slip in CuNb Multilayers.pdf},
issn = {1431-9276},
keyword = {confined layer slip, Cu-Nb interfaces, in situ indentation}
}
@article{li_dislocation_2010,
author = {Li, Xiaoyan and Wei, Yujie and Lu, Lei and Lu, Ke and Gao, Huajian},
title = {Dislocation nucleation governed softening and maximum strength in nano-twinned metals},
file = {/home/aselimov/docs/My Library/files/635/Li et al. - 2010 - Dislocation nucleation governed softening and maximum strength in nano-twinned metals.pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/658/Lin et al. - 2016 - Measuring nonlinear stresses generated by defects in 3D colloidal crystals(2).pdf},
author = {Li, Yi and Zhou, Qing and Zhang, Shuang and Huang, Ping and Xu, Kewei and Wang, Fei and Lu, Tianjian},
title = {On the role of weak interface in crack blunting process in nanoscale layered composites},
journal = {Applied Surface Science},
year = {2018},
volume = {433},
pages = {957--962},
doi = {10.1016/j.apsusc.2017.10.002},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/616/Li et al. - 2018 - On the role of weak interface in crack blunting process in nanoscale layered composites.pdf},
title = {Role of persistent slip bands in fatigue},
journal = {Philosophical Magazine},
year = {2004},
number = {3-5},
volume = {84},
pages = {317--330},
doi = {10.1080/14786430310001610339},
abstract = {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.},
issn = {14786435},
keyword = {Fatigue, Persistant Slip Bands, PSB}
}
@article{mae_instability_2002,
author = {Mae, K. and Nobata, T. and Ishida, H. and Motoyama, S. and Hiwatari, Y.},
title = {Instability of hcp structures in modified embedded atom method},
journal = {Modelling and Simulation in Materials Science and Engineering},
year = {2002},
volume = {10},
pages = {205--214},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/720/Rawat et al. - 2002 - Modelling and Simulation in Materials Science and Engineering Related content Instability of hcp structures in mod.pdf}
}
@article{Mara_2015,
author = {Mara, Nathan A. and Beyerlein, Irene J.},
title = {Interface-dominant multilayers fabricated by severe plastic deformation: Stability under extreme conditions},
journal = {Current Opinion in Solid State and Materials Science},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/678/Mastorakos, Zbib, Bahr - 2009 - Deformation mechanisms and strength in nanoscale multilayer metallic composites with coherent and incohe.pdf},
abstract = {\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},
file = {/home/aselimov/docs/My Library/files/880/Mastorakos et al. - 2011 - Size-dependent strength in nanolaminate metallic systems.pdf},
issn = {0884-2914},
keyword = {Simulation, Hardness, Nanostructure}
}
@article{matthews_defects_1975,
author = {Matthews, J.W. and Blakeslee, A.E.},
title = {Defects in epitaxial multilayers: {II}. {Dislocation} pile-ups, threading dislocations, slip lines and cracks},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/710/Matthews, Blakeslee - 1975 - Defects in epitaxial multilayers II. Dislocation pile-ups, threading dislocations, slip lines and cracks.pdf},
issn = {0022-0248},
keyword = {NMM}
}
@incollection{McDowell_2018,
author = {McDowell, David L.},
title = {Multiscale Modeling of Interfaces, Dislocations, and Dislocation Field Plasticity},
author = {Mendelev, M. I. and Underwood, T. L. and Ackland, G. J.},
title = {Development of an interatomic potential for the simulation of defects, plasticity, and phase transformations in titanium},
journal = {Journal of Chemical Physics},
year = {2016},
number = {15},
volume = {145},
doi = {10.1063/1.4964654},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/857/Mendelev, Underwood, Ackland - 2016 - Development of an interatomic potential for the simulation of defects, plasticity, and phase tr(3).pdf},
issn = {00219606}
}
@article{miller_quasicontinuum_1999,
author = {Miller, R and Tadmor, E B and Phillips, R and Ortiz, M},
title = {Quasicontinuum simulation of fracture at the atomic scale},
journal = {Modelling and Simulation in Materials Science and Engineering},
year = {1999},
number = {5},
volume = {6},
pages = {607--638},
doi = {10.1088/0965-0393/6/5/008},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/676/Miller et al. - 1999 - Quasicontinuum simulation of fracture at the atomic scale(2).pdf},
doi = {https://doi.org/10.1533/9781845691189.146},
abstract = {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.},
booktitle = {Nanostructure Control of Materials},
editor = {Hannink, R. H. J. and Hill, A. J.},
isbn = {978-1-85573-933-8}
}
@article{misra_length-scale-dependent_2005,
author = {Misra, A. and Hirth, J. P. and Hoagland, R. G.},
title = {Length-scale-dependent deformation mechanisms in incoherent metallic multilayered composites},
title = {Hall-petch relation in nanocrystalline solids},
journal = {Scripta Metallurgica et Materiala},
year = {1991},
number = {4},
volume = {25},
pages = {955--958},
doi = {10.1016/0956-716X(91)90256-Z},
abstract = {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.},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/644/Nizolek et al. - 2016 - Tensile behavior and flow stress anisotropy of accumulative roll bonded Cu-Nb nanolaminates.pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/838/Nye - 1953 - Some geometrical relations in dislocated crystals.pdf},
issn = {0001-6160}
}
@article{of_colorado_lumped_2010,
author = {of Colorado, University},
title = {Lumped and {Consisitent} {Mass} {Matrices}},
journal = {Introduction To Finite Element Mehtods},
year = {2010},
pages = {31.1--31.23},
file = {/home/aselimov/docs/My Library/files/696/Colorado - 2010 - Lumped and Consisitent Mass Matrices.pdf}
}
@article{onat_optimized_2014,
author = {Onat, Berk and Durukanoǧlu, Sondan},
title = {An optimized interatomic potential for {Cu}-{Ni} alloys with the embedded-atom method},
journal = {Journal of Physics Condensed Matter},
year = {2014},
number = {3},
volume = {26},
doi = {10.1088/0953-8984/26/3/035404},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/642/Onat, Durukanoǧlu - 2014 - An optimized interatomic potential for Cu-Ni alloys with the embedded-atom method.pdf},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/666/Parrinello, Rahman - 1981 - Polymorphic transitions in single crystals A new molecular dynamics method.pdf},
author = {Pedrazzini, S. and Galano, M. and Audebert, F. and Collins, D. M. and Hofmann, F. and Abbey, B. and Korsunsky, A. M. and Lieblich, M. and Escorial, A. Garcia and Smith, G. D. W.},
title = {Strengthening mechanisms in an Al-Fe-Cr-Ti nano-quasicrystalline alloy and composites},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/622/Pei et al. - 2018 - Tunable twin stability and an accurate magnesium interatomic potential for dislocation-twin interactions.pdf},
issn = {18734197},
keyword = {Dislocations, EAM potential, Stacking faults, Tunable twin boundaries}
}
@book{plimpton_fast_1995,
author = {Plimpton, Steve},
title = {Fast {Parallel} {Algorithms} for {Short}-{Range} {Molecular} {Dynamics}},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/694/Plimpton - 1995 - Fast Parallel Algorithms for Short-Range Molecular Dynamics(2).pdf},
isbn = {0021-9991},
pmid = {8987871}
}
@article{potirniche_molecular_2006,
author = {Potirniche, G.P. and Horstemeyer, M.F. and Wagner, G.J. and Gullett, P.M.},
title = {A molecular dynamics study of void growth and coalescence in single crystal nickel},
abstract = {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 ({\textbackslash}textgreater20\%), 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.},
file = {/home/aselimov/docs/My Library/files/680/Potirniche et al. - 2006 - A molecular dynamics study of void growth and coalescence in single crystal nickel.pdf},
issn = {0749-6419}
}
@article{Priedeman_2018,
author = {Priedeman, Jonathan L. and Rosenbrock, Conrad W. and Johnson, Oliver K. and Homer, Eric R.},
title = {Quantifying and connecting atomic and crystallographic grain boundary structure using local environment representation and dimensionality reduction techniques},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/662/Quek et al. - 2016 - The inverse hall-petch relation in nanocrystalline metals A discrete dislocation dynamics analysis(2).pdf},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/706/Rao, Hazzledine - 2000 - Atomistic simulations of dislocation–interface interactions in the Cu-Ni multilayer system.pdf},
issn = {0141-8610},
keyword = {NMM}
}
@article{rawat_modelling_2002,
author = {Rawat, Sunil and Mitra, Nilanjan and Rawat, Sunil and Mitra, Nilanjan},
title = {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},
year = {2002},
file = {/home/aselimov/docs/My Library/files/624/Rawat et al. - 2002 - Modelling and Simulation in Materials Science and Engineering Related content Instability of hcp structures in mod.pdf}
}
@article{rawat_molecular_2018,
author = {Rawat, Sunil and Mitra, Nilanjan},
title = {Molecular dynamics investigation of c-axis deformation of single crystal {Ti} under uniaxial stress conditions: {Evolution} of compression twinning and dislocations},
file = {/home/aselimov/docs/My Library/files/730/Rawat, Mitra - 2018 - Molecular dynamics investigation of c-axis deformation of single crystal Ti under uniaxial stress conditions Ev(2).pdf},
file = {/home/aselimov/docs/My Library/files/609/Rice - 1967 - A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks(2).pdf}
}
@article{ritchie_mechanisms_1988,
author = {Ritchie, R. O.},
title = {Mechanisms of fatigue crack propagation in metals, ceramics and composites: {Role} of crack tip shielding},
journal = {Materials Science and Engineering},
year = {1988},
number = {1},
volume = {103},
pages = {15--28},
doi = {10.1016/0025-5416(88)90547-2},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/878/Ritchie - 1988 - Mechanisms of fatigue crack propagation in metals, ceramics and composites Role of crack tip shielding(2).pdf},
issn = {00255416}
}
@article{rudd_coarse-grained_2005,
author = {Rudd, Robert and Broughton, Jeremy},
title = {Coarse-grained molecular dynamics: {Nonlinear} finite elements and finite temperature},
abstract = {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},
file = {/home/aselimov/docs/My Library/files/700/Rudd, Broughton - 2005 - Coarse-grained molecular dynamics Nonlinear finite elements and finite temperature(2).pdf},
issn = {1098-0121}
}
@article{rudd_concurrent_2000,
author = {Rudd, R.E. and Broughton, J.Q.},
title = {Concurrent {Coupling} of {Length} {Scales} in {Solid} {State} {Systems}},
doi = {10.1002/(SICI)1521-3951(200001)217:1<251::AID-PSSB251>3.0.CO;2-A},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/869/Rudd, Broughton - 2000 - Concurrent Coupling of Length Scales in Solid State Systems(2).pdf},
issn = {0370-1972}
}
@article{ruestes_atomistic_2017,
author = {Ruestes, Carlos and Alhafez, Iyad and Urbassek, Herbert and Ruestes, Carlos J. and Alhafez, Iyad Alabd and Urbassek, Herbert M.},
title = {Atomistic {Studies} of {Nanoindentation}— {A} {Review} of {Recent} {Advances}},
journal = {Crystals},
year = {2017},
month = {September},
number = {10},
volume = {7},
pages = {293},
url = {http://www.mdpi.com/2073-4352/7/10/293},
doi = {10.3390/cryst7100293},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/619/Ruestes et al. - 2017 - Atomistic Studies of Nanoindentation—A Review of Recent Advances.pdf},
author = {Sadananda, K. and Ramaswamy, Dorai Nirmal V.},
title = {Role of crack tip plasticity in fatigue crack growth},
journal = {Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties},
year = {2001},
number = {5},
volume = {81},
pages = {1283--1303},
doi = {10.1080/01418610108214441},
abstract = {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.\${\textbackslash}backslash\$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.},
file = {/home/aselimov/docs/My Library/files/717/Sadananda, Ramaswamy - 2001 - Role of crack tip plasticity in fatigue crack growth(2).pdf},
issn = {01418610}
}
@article{Saito_1999,
author = {Saito, Y. and Utsunomiya, H. and Tsuji, N. and Sakai, T.},
title = {Novel ultra-high straining process for bulk materials—development of the accumulative roll-bonding (ARB) process},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/718/Schiotz, Jacobsen - 2003 - A Maximum in the Strength of Nanocrystalline Copper.pdf},
issn = {1095-9203},
pmid = {11935012}
}
@article{schuh_hall-petch_2002,
author = {Schuh, C. A. and Nieh, T. G. and Yamasaki, T.},
title = {Hall-{Petch} breakdown manifested in abrasive wear resistance of nanocrystalline nickel},
author = {Shao, S. and Zbib, H. M. and Mastorakos, I. and Bahr, D. F.},
title = {Effect of Interfaces in the Work Hardening of Nanoscale Multilayer Metallic Composites During Nanoindentation: A Molecular Dynamics Investigation},
journal = {Journal of Engineering Materials and Technology},
publisher = {ASME International},
year = {2013},
month = {mar},
number = {2},
volume = {135},
url = {https://doi.org/10.1115%2F1.4023672},
doi = {10.1115/1.4023672}
}
@article{Shao_2013,
author = {Shao, Shuai and Wang, Jian and Misra, Amit and Hoagland, Richard G.},
title = {Spiral Patterns of Dislocations at Nodes in (111) Semi-coherent FCC Interfaces},
journal = {Scientific Reports},
publisher = {Springer Science and Business Media LLC},
year = {2013},
month = {aug},
number = {1},
volume = {3},
url = {https://doi.org/10.1038%2Fsrep02448},
doi = {10.1038/srep02448}
}
@article{Shao_2014,
author = {Shao, Shuai and Wang, J. and Misra, Amit},
title = {Energy minimization mechanisms of semi-coherent interfaces},
journal = {Journal of Applied Physics},
publisher = {AIP Publishing},
year = {2014},
month = {jul},
number = {2},
volume = {116},
pages = {023508},
url = {https://doi.org/10.1063%2F1.4889927},
doi = {10.1063/1.4889927}
}
@article{Shao_2015,
author = {Shao, Shuai and Wang, Jian and Beyerlein, Irene J. and Misra, Amit},
file = {/home/aselimov/docs/My Library/files/687/Shen et al. - 2018 - Preparation and properties of nano-multilayer films by rotating jet electrodeposition.pdf},
abstract = {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.},
title = {An introduction to tensor calculus, relativity, and cosmology},
journal = {Acta Applicandae Mathematicae},
year = {2008},
number = {2},
volume = {11},
pages = {193--195},
doi = {10.1007/BF00047288},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/866/Smirnov - 2008 - An introduction to tensor calculus, relativity, and cosmology(2).pdf},
issn = {0167-8019},
pmid = {12934667}
}
@article{Snel_2017,
author = {Snel, J. and Monclús, M. A. and Castillo-Rodríguez, M. and Mara, N. and Beyerlein, I. J. and Llorca, J. and Molina-Aldareguía, J. M.},
title = {Deformation Mechanism Map of Cu/Nb Nanoscale Metallic Multilayers as a Function of Temperature and Layer Thickness},
journal = {JOM},
publisher = {Springer Science and Business Media LLC},
file = {/home/aselimov/docs/My Library/files/695/Sobie et al. - 2017 - Scale transition using dislocation dynamics and the nudged elastic band method(2).pdf},
issn = {00225096}
}
@article{sobie_thermal_2017,
author = {Sobie, Cameron and Capolungo, Laurent and McDowell, David L. and Martinez, Enrique},
title = {Thermal activation of dislocations in large scale obstacle bypass},
journal = {Journal of the Mechanics and Physics of Solids},
year = {2017},
volume = {105},
pages = {150--160},
doi = {10.1016/j.jmps.2017.05.003},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/879/Sobie et al. - 2017 - Thermal activation of dislocations in large scale obstacle bypass(2).pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/675/Stueber et al. - 2009 - Concepts for the design of advanced nanoscale PVD multilayer protective thin films.pdf},
issn = {0925-8388},
keyword = {NMM, PVD}
}
@article{Stukowski_2009,
author = {Stukowski, Alexander},
title = {Visualization and analysis of atomistic simulation data with OVITO–the Open Visualization Tool},
journal = {Modelling and Simulation in Materials Science and Engineering},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/842/Stukowski - 2014 - Computational Analysis Methods in Atomistic Modeling of Crystals.pdf},
issn = {10474838},
keyword = {DXA}
}
@article{stukowski_dislocation_2010,
author = {Stukowski, Alexander and Albe, Karsten},
title = {Dislocation detection algorithm for atomistic simulations},
journal = {Modelling and Simulation in Materials Science and Engineering},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/646/Stukowski, Arsenlis - 2012 - On the elastic–plastic decomposition of crystal deformation at the atomic scale.pdf},
issn = {0965-0393},
keyword = {DXA}
}
@article{stukowski_triangulation-based_2014,
author = {Stukowski, Alexander},
title = {A triangulation-based method to identify dislocations in atomistic models},
journal = {Journal of the Mechanics and Physics of Solids},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/829/Stukowski - 2014 - A triangulation-based method to identify dislocations in atomistic models.pdf},
issn = {0022-5096}
}
@article{subedi_strength_2018,
author = {Subedi, Samikshya and Beyerlein, Irene J. and LeSar, Richard and Rollett, Anthony D.},
title = {Strength of nanoscale metallic multilayers},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/685/Strenght of nanoscale metallic multilayers.pdf},
abstract = {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{\textbackslash}textgreater0K).},
file = {/home/aselimov/docs/My Library/files/661/Subramaniyan, Sun - 2008 - Continuum interpretation of virial stress in molecular simulations.pdf},
issn = {0020-7683}
}
@article{Sun_2020,
author = {Sun, Yufeng and Chen, Yao and Tsuji, Nobuhiro and Guan, Shaokang},
title = {Microstructural evolution and mechanical properties of nanostructured Cu/Ni multilayer fabricated by accumulative roll bonding},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/665/Disconnections, dislocations and generalized siclinations in grain boundary ledges.pdf},
issn = {07496419}
}
@article{Tadmor_1996,
author = {Tadmor, E. B. and Ortiz, M. and Phillips, R.},
title = {Quasicontinuum analysis of defects in solids},
author = {Tasan, Cemal Cem and Diehl, Martin and Yan, Dingshun and Bechtold, Marion and Roters, Franz and Schemmann, Lars and Zheng, Chengwu and Peranio, Nicola and Ponge, Dirk and Koyama, Motomichi and others, },
title = {An overview of dual-phase steels: advances in microstructure-oriented processing and micromechanically guided design},
title = {Atomistic {Simulations} of {Dislocation} {Nucleation} in {Single} {Crystals} and {Grain} {Boundaries} {Atomistic} {Simulations} of {Dislocation} {Nucleation}},
year = {2007},
abstract = {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 {\textbackslash}pounds3 asymmetric boundaries can be decomposed into the structural units of the {\textbackslash}pounds3 symmetric tilt grain boundaries, i.e., the coherent and incoherent twin boundaries. Moreover, the energy for all {\textbackslash}pounds3 asymmetric boundaries is predicted with only the energies of the {\textbackslash}pounds3 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 {\textbackslash}pounds 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.},
file = {/home/aselimov/docs/My Library/files/618/Tschopp - 2007 - Atomistic Simulations of Dislocation Nucleation in Single Crystals and Grain Boundaries Atomistic Simulations of Dis(3).pdf},
school = {Georgia Institute of Technology}
}
@article{tschopp_atomistic_2008,
author = {Tschopp, M.A. and Tucker, G.J. and McDowell, D.L.},
title = {Atomistic simulations of tension–compression asymmetry in dislocation nucleation for copper grain boundaries},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/629/Tschopp, Tucker, McDowell - 2008 - Atomistic simulations of tension–compression asymmetry in dislocation nucleation for copper grain b.pdf},
issn = {0927-0256}
}
@article{Tucker_2009,
author = {Tucker, G J and Zimmerman, J A and McDowell, D L},
title = {Shear deformation kinematics of bicrystalline grain boundaries in atomistic simulations},
journal = {Modelling and Simulation in Materials Science and Engineering},
abstract = {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},
file = {/home/aselimov/docs/My Library/files/853/Voter, Chen - 1986 - Accurate interatomic potentials for Ni, Al, and Ni3Al.pdf}
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/645/Wang et al. - 2008 - Atomistic modeling of the interaction of glide dislocations with weak interfaces(2).pdf;Wang-2008-Acta-Materialia.pdf:/home/aselimov/Literature/Wang-2008-Acta-Materialia.pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/674/Wang, Lu, Zhang - 2013 - A Frank scheme of determining the Burgers vectors of dislocations in a FCC crystal.pdf},
issn = {0927-0256}
}
@article{wang_interface_2014,
author = {Wang, J. and Zhang, R. F. and Zhou, C. Z. and Beyerlein, I. J. and Misra, A.},
title = {Interface dislocation patterns and dislocation nucleation in face-centered-cubic and body-centered-cubic bicrystal interfaces},
file = {/home/aselimov/docs/My Library/files/719/Wang et al. - 2014 - Interface dislocation patterns and dislocation nucleation in face-centered-cubic and body-centered-cubic bicrystal.pdf},
abstract = {Thesis (Master's)–University of Washington, 2012},
file = {/home/aselimov/docs/My Library/files/683/Wang - 2012 - Material Characterization of Electrodeposited Copper-Nickel Nanolaminated Alloy by SEM, EDS, and XRD.pdf},
keyword = {characterization, Cu-Ni, EDS, Engineering, Materials Science, Materials science and engineering, nanolaminate, SEM, XRD}
}
@article{wang_strong_2015,
author = {Wang, Jiangwei and Sansoz, Frederic and Deng, Chuang and Xu, Gang and Han, Gaorong and Mao, Scott X.},
title = {Strong {Hall}-{Petch} {Type} {Behavior} in the {Elastic} {Strain} {Limit} of {Nanotwinned} {Gold} {Nanowires}},
file = {/home/aselimov/docs/My Library/files/673/Wang et al. - 2015 - Strong Hall-Petch Type Behavior in the Elastic Strain Limit of Nanotwinned Gold Nanowires.pdf},
issn = {15306992},
keyword = {elastic strain engineering, Hall-Petch hardening, ideal elastic strain limit, in situ transmission electron microscopy, metallic nanowires, Nanotwin}
}
@article{warner_atomistic_2006,
author = {Warner, D. H. and Sansoz, F. and Molinari, J. F.},
title = {Atomistic based continuum investigation of plastic deformation in nanocrystalline copper},
author = {Warner, D. H. and Curtin, W. A. and Qu, S.},
title = {Rate dependence of crack-tip processes predicts twinning trends in f.c.c. metals},
journal = {Nature Materials},
year = {2007},
number = {11},
volume = {6},
pages = {876--881},
doi = {10.1038/nmat2030},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/655/Warner, Curtin, Qu - 2007 - Rate dependence of crack-tip processes predicts twinning trends in f.c.c. metals(2).pdf},
issn = {14764660},
keyword = {Dislocation, CADD, Crack Tip, Crack},
pmid = {17934465}
}
@article{was_deformation_1996,
author = {Was, G.S and Foecke, T},
title = {Deformation and fracture in microlaminates},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/668/Was, Foecke - 1996 - Deformation and fracture in microlaminates.pdf},
issn = {0040-6090}
}
@article{Weygand_1999,
author = {Weygand, D. and Bréchet, Y. and Lépinoux, J. and Gust, W.},
title = {Three-dimensional grain growth: A vertex dynamics simulation},
title = {The {Lattice} {Constants} of {High} {Purity} {Alpha} {Titanium}},
journal = {Proceedings of the Physical Society},
year = {2002},
number = {3},
volume = {80},
pages = {783--786},
doi = {10.1088/0370-1328/80/3/323},
abstract = {Lattice constants have been determined for a specimen of alpha titanium of greater purity than hitherto examined. Values of a0 = 2.95111 {\textbackslash}AA ± 6 × 10-5 and c0 = 4.684 33 {\textbackslash}AA ± 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.},
file = {/home/aselimov/docs/My Library/files/650/Wood - 2002 - The Lattice Constants of High Purity Alpha Titanium(2).pdf},
issn = {0370-1328}
}
@article{Wu_2014,
author = {Wu, X. and Jiang, P. and Chen, L. and Yuan, F. and Zhu, Y. T.},
title = {Extraordinary strain hardening by gradient structure},
journal = {Proceedings of the National Academy of Sciences},
publisher = {Proceedings of the National Academy of Sciences},
file = {/home/aselimov/docs/My Library/files/709/Wu, Wang, Wang - 2010 - Generalized-stacking-fault energy and surface properties for HCP metals A first-principles study.pdf},
issn = {01694332},
keyword = {First-principles, Generalized-stacking-fault energy (GSF), HCP metals, Surface properties}
}
@article{Xiang_2018,
author = {Xiang, Meizhen and Liao, Yi and Wang, Kun and Lu, Guo and Chen, Jun},
title = {Shock-induced plasticity in semi-coherent \{111\} Cu-Ni multilayers},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/846/Xiong et al. - 2012 - A concurrent scheme for passing dislocations from atomistic to continuum domains.pdf},
issn = {1359-6454}
}
@phdthesis{Xu_2016,
title={The concurrent atomistic-continuum method: Advancements and applications in plasticity of face-centered cubic metals},
author = {Xu, Shuozhi and Xiong, Liming and Chen, Youping and McDowell, David L.},
title = {Comparing EAM Potentials to Model Slip Transfer of Sequential Mixed Character Dislocations Across Two Symmetric Tilt Grain Boundaries in {Ni}},
journal = {JOM},
publisher = {Springer Science and Business Media LLC},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/614/Xu et al. - 2016 - An analysis of key characteristics of the Frank-Read source process in FCC metals(2).pdf},
author = {Xu, Shuozhi and Xiong, Liming and Chen, Youping and McDowell, David L.},
title = {Edge dislocations bowing out from a row of collinear obstacles in {Al}},
journal = {Scripta Materialia},
year = {2016},
volume = {123},
pages = {135--139},
doi = {10.1016/j.scriptamat.2016.06.018},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/863/Xu et al. - 2016 - Edge dislocations bowing out from a row of collinear obstacles in Al(2).pdf},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/704/Xu et al. - 2015 - A quasistatic implementation of the concurrent atomistic-continuum method for FCC crystals(3).pdf},
issn = {07496419},
keyword = {Concurrent atomistic-continuum method, A. Dislocations, B. Metallic material, C. Finite elements, C. Numerical algorithms}
}
@article{xu_sequential_2016,
author = {Xu, Shuozhi and Xiong, Liming and Chen, Youping and McDowell, David L},
title = {Sequential slip transfer of mixed-character dislocations across $\Sigma$3 coherent twin boundary in FCC metals: a concurrent atomistic-continuum study},
abstract = {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.},
file = {Xu et al. - 2016 - Sequential slip transfer of mixed-character disloc.pdf:/home/aselimov/docs/My Library/files/895/Xu et al. - 2016 - Sequential slip transfer of mixed-character disloc.pdf},
issn = {2057-3960},
keyword = {Coarse, grained models, Metals and alloys}
}
@article{xu_shear_2017,
author = {Xu, Shuozhi and Xiong, Liming and Chen, Youping and McDowell, David L.},
title = {Shear stress- and line length-dependent screw dislocation cross-slip in {FCC} {Ni}},
abstract = {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.},
abstract = {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...},
file = {/home/aselimov/docs/My Library/files/638/Xu et al. - 2017 - Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten.pdf},
author = {Yin, Fuxing and Zhao, Yizhe and Yu, Siyuan and Pang, Weiwei},
title = {Molecular dynamics studies on the interface evolution characteristics and deformation mechanisms of Cu/Al multilayers during compression process},
journal = {Journal of Applied Physics},
publisher = {AIP Publishing},
year = {2019},
month = {jan},
number = {2},
volume = {125},
pages = {025112},
url = {https://doi.org/10.1063%2F1.5055901},
doi = {10.1063/1.5055901}
}
@article{Youngs_2009,
author = {Youngs, T. G. A.},
title = {Aten-An application for the creation, editing, and visualization of coordinates for glasses, liquids, crystals, and molecules},
journal = {Journal of Computational Chemistry},
publisher = {Wiley},
year = {2009},
pages = {NA--NA},
url = {https://doi.org/10.1002%2Fjcc.21359},
doi = {10.1002/jcc.21359}
}
@article{yuan_molecular_2007,
author = {Yuan, Lin and Shan, Debin and Guo, Bin},
title = {Molecular dynamics simulation of tensile deformation of nano-single crystal aluminum},
journal = {Journal of Materials Processing Technology},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/625/Yuan, Shan, Guo - 2007 - Molecular dynamics simulation of tensile deformation of nano-single crystal aluminum.pdf},
issn = {0924-0136}
}
@article{yu_strengthening_2013,
author = {Yu, K.Y. and Liu, Y. and Rios, S. and Wang, H. and Zhang, X.},
title = {Strengthening mechanisms of {Ag}/{Ni} immiscible multilayers with fcc/fcc interface},
abstract = {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 {\textbackslash}textless111{\textbackslash}textgreater 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 {\textbackslash}textgreater 3nm. Strengthening mechanisms in Ag/Ni systems are discussed and compared to those in Cu/Ni and Ag/Cu systems with fcc/fcc interfaces.},
file = {/home/aselimov/docs/My Library/files/705/Yu et al. - 2013 - Strengthening mechanisms of AgNi immiscible multilayers with fccfcc interface(2).pdf},
issn = {0257-8972},
keyword = {NMM}
}
@article{Zbib_2012,
author = {Zbib, H. M. and Mastorakos, I. N. and Bahr, D. F.},
title = {Deformation mechanisms, size effects, and strain hardening in nanoscale metallic multilayers under nanoindentation},
journal = {Journal of Applied Physics},
publisher = {AIP Publishing},
year = {2012},
month = {aug},
number = {4},
volume = {112},
pages = {044307},
url = {https://doi.org/10.1063%2F1.4748149},
doi = {10.1063/1.4748149}
}
@article{zeng_high_2016,
author = {Zeng, L.F. and Gao, R. and Fang, Q.F. and Wang, X.P. and Xie, Z.M. and Miao, S. and Hao, T. and Zhang, T.},
title = {High strength and thermal stability of bulk {Cu}/{Ta} nanolamellar multilayers fabricated by cross accumulative roll bonding},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/861/Zeng et al. - 2016 - High strength and thermal stability of bulk CuTa nanolamellar multilayers fabricated by cross accumulative roll bon.pdf},
author = {Zhang, J. Y. and Zhang, X. and Wang, R. H. and Lei, S. Y. and Zhang, P. and Niu, J. J. and Liu, G. and Zhang, G. J. and Sun, J.},
title = {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},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/882/Zhang et al. - 2016 - Manipulating dislocation nucleation and shear resistance of bimetal interfaces by atomic steps.pdf},
issn = {1359-6454}
}
@article{zhang_modulation_2015,
author = {Zhang, B. and Kou, Y. and Xia, Y.Y. and Zhang, X.},
title = {Modulation of strength and plasticity of multiscale {Ni}/{Cu} laminated composites},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/634/Zhang et al. - 2015 - Modulation of strength and plasticity of multiscale NiCu laminated composites.pdf},
issn = {0921-5093}
}
@article{zhang_review_2016,
author = {Zhang, Liang and Lu, Cheng and Tieu, Kiet},
title = {A review on atomistic simulation of grain boundary behaviors in face-centered cubic metals},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/620/Zhang, Lu, Tieu - 2016 - A review on atomistic simulation of grain boundary behaviors in face-centered cubic metals.pdf},
abstract = {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.},
author = {Zhang, Yuting and Li, Yujie and Ding, Xiuli},
title = {Universal {Format} of {Shape} {Function} for {Numerical} {Analysis} using {Multiple} {Element} {Forms} {Universal} {Format} of {Shape} {Function} using {Linear} {Hexahedron}},
journal = {Advanced Science and Technology Letters},
year = {2016},
number = {Ast},
volume = {121},
pages = {63--67},
file = {/home/aselimov/docs/My Library/files/851/Zhang, Li, Ding - 2016 - Universal Format of Shape Function for Numerical Analysis using Multiple Element Forms Universal Format of Shap.pdf},
author = {Zherebtsov, Sergey and Salishchev, Gennady and Lee Semiatin, S.},
title = {Loss of coherency of the alpha/beta interface boundary in titanium alloys during deformation},
journal = {Philosophical Magazine Letters},
year = {2010},
number = {12},
volume = {90},
pages = {903--914},
doi = {10.1080/09500839.2010.521526},
abstract = {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\${\textbackslash}backslash\$,{\textasciicircum}\{\${\textbackslash}backslash\$circ\}C.},
file = {/home/aselimov/docs/My Library/files/707/Zherebtsov, Salishchev, Lee Semiatin - 2010 - Loss of coherency of the alphabeta interface boundary in titanium alloys during deformatio.pdf},
title = {Introduction to interatomic potentials ({I})},
journal = {None},
year = {2013},
number = {I},
abstract = {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 , {\textbackslash}ldots, r N) describes how the potential energy of a system of N atoms depends on the coordinates of the atoms, r 1 , r 2 , {\textbackslash}ldots, 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)},
file = {/home/aselimov/docs/My Library/files/887/Zhou - 2003 - A new look at the atomic level virial stress on continuum-molecular system equivalence.pdf},
issn = {1471-2946}
}
@article{Zhu_2020,
author = {Zhu, Yuntian and Ameyama, Kei and Anderson, Peter M. and Beyerlein, Irene J. and Gao, Huajian and Kim, Hyoung Seop and Lavernia, Enrique and Mathaudhu, Suveen and Mughrabi, Hael and Ritchie, Robert O. and Tsuji, Nobuhiro and Zhang, Xiangyi and Wu, Xiaolei},
title = {Heterostructured materials: superior properties from hetero-zone interaction},
abstract = {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.},
file = {/home/aselimov/docs/My Library/files/691/Zhu et al. - 2010 - Scale-dependent fracture mode in Cu–Ni laminate composites.pdf},
