Discrete dislocation dynamics simulations of plasticity at small scales

TitleDiscrete dislocation dynamics simulations of plasticity at small scales
Publication TypeJournal Article
Year of Publication2010
AuthorsZhou CZ, Biner SB, LeSar R
Journal TitleActa Materialia
Volume58
Pages1565-1577
Date Published03/01
ISBN Number1359-6454
Accession NumberISI:000274931200011
Keywordscross-slip, dislocation dynamics, fcc, high-rate deformation, mechanical-properties, micrometer-scale, nickel microcrystals, plasticity, single-crystals, size dependence, size effects, stress-strain behavior, UNIAXIAL COMPRESSION
Abstract

Discrete dislocation dynamics simulations in three dimensions have been used to examine the role of dislocation multiplication and mobility on the plasticity in small samples under uniaxial compression. To account for the effects of the free surfaces a boundary-element method, with a superposition technique, was employed. Cross-slip motion of the dislocation was also included, and found to be critical to the modeling of the dislocation behavior. To compare directly with recent experiments on micropillars, simulation samples at small volumes were created by cutting them from bulk three-dimensional simulations, leading to a range of initial dislocation structures. Application was made to single-crystal nickel samples. Comparison of the simulation results and the experiments are excellent, finding essentially identical behavior. Examination of details of the dislocation mechanism illuminates many features unique to small samples and points directly to the importance of both the surface forces and cross-slip in understanding small-scale plasticity. (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

URL<Go to ISI>://000274931200011
DOIDoi 10.1016/J.Actamat.2009.11.001