Discrete Dislocation Dynamics Simulations of Plasticity at Small Scales

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.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Dislocation Dynamics; Plasticity; Size Effects; Cross-Slip; Discrete Dislocation Dynamics; Dislocation Mechanisms; Dislocation Multiplication; Dislocation Structures; Element Method; Free Surfaces; Micro-Pillars; Simulation Result; Small Samples; Small Scale; Superposition Technique; Surface Forces; Three Dimensional Simulations; Uni-Axial Compression

International Standard Serial Number (ISSN)

1359-6454

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2010 Elsevier Limited, All rights reserved.

Publication Date

01 Mar 2010

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