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Three-dimensional Boundary Element- Dislocation Dynamics Modeling of Plastic Flow in Small Volumes

Published online by Cambridge University Press:  26 February 2011

Nasr Ghoniem
Affiliation:
UCLA
Jaafar El-Awady
Affiliation:
UCLA
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Abstract

Format

This is a copy of the slides presented at the meeting but not formally written up for the volume.

Abstract

We present a self-consistent formulation of 3-D Parametric Dislocation Dynamics (PDD) with the Boundary Element method (BEM) to describe dislocation motion, and hence microscopic plastic flow in finite volumes. We develop quantitative measures of the accuracy and convergence of the method by considering a comparison with known analytical solutions. It is shown that the method displays absolute convergence with increasing the number of quadrature points on the dislocation loop and the surface mesh density. For example, at a distance of one lattice parameter from the surface, the relative error is less than 5% for a surface mesh with an element size of 1000 x 2000 lattice parameters, and 64 quadrature points. The Eshelby twist in a finite length cylinder containing a coaxial screw dislocation is also used to benchmark the method. Simulation results of single slip behavior in cylindrical microcrystals is presented, and the general features are compared to single-crystal compression experiments. The method is utilized to study size scaling aspects of plastic flow in small volumes and assess the role of the dislocation starvation mechanism.

Keywords

Type
Slide Presentations
Copyright
Copyright © Materials Research Society 2006

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