The role of the weakest-link mechanism in controlling the plasticity of micropillars

被引：134

作者：

El-Awady, Jaafar A. ^{[1
]}

Wen, Ming ^{[1
]}

Ghoniem, Nasf M. ^{[1
]}

机构：

[1] Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA

来源：

JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS | 2009年 / 57卷 / 01期

关键词：

Size effects; Dislocations dynamics; Plasticity; Micropillars; Nickel; PARAMETRIC DISLOCATION DYNAMICS; SINGLE-CRYSTALS; STRENGTH; COMPRESSION; DEFORMATION; SCALE; DEPENDENCE; PILLARS; ORIENTATION; SIMULATION;

D O I：

10.1016/j.jmps.2008.10.004

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We present a computational study on the effects of sample size on the strength and plastic flow characteristics of micropillars under compression loading. We conduct three-dimensional simulations using the parametric dislocation dynamics coupled with the boundary element method. Two different loading techniques are performed. The plastic flow characteristics as well as the stress-strain behavior of simulated micropillars are shown to be in general agreement with experimental observations. The flow strength versus the diameter of the micropillar follows a power law with an exponent equal to -0.69. A stronger correlation is observed between the flow strength and the average length of activated dislocation sources. This relationship is again a power law, with an exponent -0.85. Simulation results with and without the activation of cross-slip are compared. Discontinuous hardening is observed when cross-slip is included. Experimentally observed size effects on plastic flow and work-hardening are consistent with a "weakest-link activation mechanism". (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：32 / 50

页数：19

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