scholarly journals Zbigniew Stanislaw Basinski, O.C. 28 April 1928 – 12 August 1999

2001 ◽  
Vol 47 ◽  
pp. 1-17 ◽  
Author(s):  
Archie Howie
Keyword(s):  
Crystal Plasticity ◽  
Dislocation Motion ◽  
Experimental Investigations ◽  
Lifelong Partner

Zbigniew Basinski, widely known as Bas, was exposed early in life to turbulent events in Poland, Russia and Palestine. He studied chemistry at Oxford, then performed research in metal physics with Jack Christian (F.R.S. 1975). There he met Sylvia Pugh, his wife and lifelong partner, in an enduring and passionate study of crystal plasticity pursued largely in Canada. Over most of the period since the dislocation concept transformed the problem of explaining crystal weakness into one of explaining crystal strength, Basinski's experimental investigations of the obstacles to dislocation motion surpassed in quality and variety those of any other worker.

Numerical Study on Bicrystalline Micropillar Compression Using High-Order Gradient Crystal Plasticity

2019 ◽  
Vol 794 ◽  
pp. 65-70
Author(s):  
Yuichi Tadano
Keyword(s):  
Grain Boundary ◽  
Crystal Plasticity ◽  
Numerical Study ◽  
Boundary Effect ◽  
Large Angle ◽  
Dislocation Motion ◽  
Element Analysis ◽  
Metallic Material ◽  
Micropillar Compression ◽  
Grain Boundary Effect

Dislocation structures at crystalline scale play an important role in the scale effect of materials. The higher-order crystal plasticity, in which a dislocation information is introduced as the gradient of slip and affects the hardening behavior of slip, is a useful model to describe a scale dependency of metallic material. In this study, a large deformation finite element analysis of a bicrystalline micropillar is demonstrated to investigate the grain boundary effect on the dislocation motion. The effect of condition on the grain boundary is numerically discussed. It is suggested that the large angle grain boundary and the coherent twin boundary can be represented by boundary conditions of non-penetration and penetration of dislocation.

scholarly journals A stochastic solver based on the residence time algorithm for crystal plasticity models

2021 ◽  
Author(s):  
Qianran Yu ◽  
Enrique Martínez ◽  
Javier Segurado ◽  
Jaime Marian
Keyword(s):  
Residence Time ◽  
Crystal Plasticity ◽  
Evolution Equations ◽  
Time Algorithm ◽  
Dislocation Motion ◽  
Crystalline Materials ◽  
Stochastic Fluctuations ◽  
Dislocation Behavior ◽  
Plastic Localization ◽  
Large Material

AbstractThe deformation of crystalline materials by dislocation motion takes place in discrete amounts determined by the Burgers vector. Dislocations may move individually or in bundles, potentially giving rise to intermittent slip. This confers plastic deformation with a certain degree of variability that can be interpreted as being caused by stochastic fluctuations in dislocation behavior. However, crystal plasticity (CP) models are almost always formulated in a continuum sense, assuming that fluctuations average out over large material volumes and/or cancel out due to multi-slip contributions. Nevertheless, plastic fluctuations are known to be important in confined volumes at or below the micron scale, at high temperatures, and under low strain rate/stress deformation conditions. Here, we develop a stochastic solver for CP models based on the residence-time algorithm that naturally captures plastic fluctuations by sampling among the set of active slip systems in the crystal. The method solves the evolution equations of explicit CP formulations, which are recast as stochastic ordinary differential equations and integrated discretely in time. The stochastic CP model is numerically stable by design and naturally breaks the symmetry of plastic slip by sampling among the active plastic shear rates with the correct probability. This can lead to phenomena such as intermittent slip or plastic localization without adding external symmetry-breaking operations to the model. The method is applied to body-centered cubic tungsten single crystals under a variety of temperatures, loading orientations, and imposed strain rates.

Introduction To Crystal Dislocations

2006 ◽  
Author(s):  
Vasily Bulatov ◽  
Wei Cai
Keyword(s):  
Crystal Plasticity ◽  
Computational Models ◽  
Electronic Device ◽  
Mathematical Concept ◽  
Dislocation Motion ◽  
Perfect Crystal ◽  
Reactor Wall ◽  
Mathematical Concepts ◽  
Semiconductor Chip ◽  
Vito Volterra

Dislocations first appeared as an abstract mathematical concept. In the late 19th century, Italian mathematician Vito Volterra examined mathematical properties of singularities produced by cutting and shifting matter in a continuous solid body [1]. As happened to some other mathematical concepts, dislocations could have remained a curious product of mathematical imagination known only to a handful of devoted mathematicians. In 1934, however, three scientists, Taylor, Polanyi and Orowan, independently proposed that dislocations may be responsible for a crystal’s ability to deform plastically [2, 3, 4]. While successfully explaining most of the puzzling phenomenology of crystal plasticity, crystal dislocations still remained mostly a beautiful hypothesis until the late 1950s when first sightings of them were reported in transmission electron microscopy (TEM) experiments [5]. Since then, the ubiquity and importance of dislocations for crystal plasticity and numerous other aspects of material behavior have been regarded as firmly established as, say, the role of DNA in promulgating life. Dislocations define a great many properties of crystalline materials. In addition to a crystal’s ability to yield and flow under stress, dislocations also control other mechanical behaviors such as creep and fatigue, ductility and brittleness, indentation hardness and friction. Furthermore, dislocations affect how a crystal grows from solution, how a nuclear reactor wall material is damaged by radiation, and whether or not a semiconductor chip in an electronic device will function properly. It can take an entire book just to describe the various roles dislocations play in materials behavior. However, the focus of this book is on the various computational models that have been developed to study dislocations. This chapter is an introduction to the basics of dislocations, setting the stage for subsequent discussions of computational models and associated numerical issues. Like any other crystal defect, dislocations are best defined with respect to the host crystal structure. We begin our discussion by presenting in Section 1.1 the basic elements and common terminology used to describe perfect crystal structures. Section 1.2 introduces the dislocation as a defect in the crystal lattice and discusses some of its essential properties. Section 1.3 discusses forces on dislocations and atomistic mechanisms for dislocation motion.

scholarly journals Sweep-tracing algorithm: in silico slip crystallography and tension-compression asymmetry in BCC metals

2022 ◽  
Vol 6 (1) ◽  
Author(s):  
Nicolas Bertin ◽  
L.A. Zepeda-Ruiz ◽  
V.V. Bulatov
Keyword(s):  
Crystal Plasticity ◽  
In Silico ◽  
Large Scale ◽  
Mechanical Response ◽  
Md Simulations ◽  
Dislocation Motion ◽  
Computational Method ◽  
Dislocation Slip ◽  
Bcc Metals ◽  
Tracing Algorithm

AbstractDirect Molecular Dynamics (MD) simulations are being increasingly employed to model dislocation-mediated crystal plasticity with atomic resolution. Thanks to the dislocation extraction algorithm (DXA), dislocation lines can be now accurately detected and positioned in space and their Burgers vector unambiguously identified in silico, while the simulation is being performed. However, DXA extracts static snapshots of dislocation configurations that by themselves present no information on dislocation motion. Referred to as a sweep-tracing algorithm (STA), here we introduce a practical computational method to observe dislocation motion and to accurately quantify its important characteristics such as preferential slip planes (slip crystallography). STA reconnects pairs of successive snapshots extracted by DXA and computes elementary slip facets thus precisely tracing the motion of dislocation segments from one snapshot to the next. As a testbed for our new method, we apply STA to the analysis of dislocation motion in large-scale MD simulations of single crystal plasticity in BCC metals. We observe that, when the crystal is subjected to uniaxial deformation along its [001] axis, dislocation slip predominantly occurs on the {112} maximum resolved shear stress plane under tension, while in compression slip is non-crystallographic (pencil) resulting in asymmetric mechanical response. The marked contrast in the observed slip crystallography is attributed to the twinning/anti-twinning asymmetry of shears in the {112} planes relatively favoring dislocation motion in the twinning sense while hindering dislocations from moving in the anti-twinning directions.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

Experimental investigations of the use of cartilage in tympanic membrane reconstruction

2000 ◽  
Vol 21 (3) ◽  
pp. 322-328 ◽  
Author(s):  
T ZAHNERT ◽  
K HUTTENBRINK ◽  
D MURBE ◽  
M BORNITZ
Keyword(s):  
Tympanic Membrane ◽  
Experimental Investigations

DISLOCATION MOTION IN VA METALS STUDIED BY INTERNAL FRICTION

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-67-C5-72
Author(s):  
S. Okuda ◽  
H. Mizubayashi ◽  
N. Kuramochi ◽  
S. Amano ◽  
M. Shimada ◽  
...  
Keyword(s):  
Internal Friction ◽  
Dislocation Motion
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