Experimental Observations of Stress-Driven Grain Boundary Migration
Experimental Observations of Stress-Driven Grain Boundary Migration
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DOI：
10.1126/science.1178226
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发表时间：
2009-12-18
期刊：
影响因子：
56.9
通讯作者：
Hemker, K. J.
中科院分区：
文献类型：
--
作者：
Rupert, T. J.;Gianola, D. S.;Hemker, K. J.
在晶体材料中，塑性变形是通过位错的运动发生的，单个晶体之间的区域称为晶界，是位错运动的障碍。晶界被广泛认为是力学上的静态结构，但这篇报告概述了在纳米晶铝薄膜中表现为晶界生长的应力驱动晶界迁移的实验研究。用特殊设计的应力和应变集中器制作的试件被用来揭示这些参数对晶粒生长的相对重要性。与传统的将晶界描述为位错塑性的静止障碍不同，本研究的结果表明，剪应力驱动晶界以一种与最近的分子动力学模拟和耦合晶界迁移的理论预测一致的方式移动。
In crystalline materials, plastic deformation occurs by the motion of dislocations, and the regions between individual crystallites, called grain boundaries, act as obstacles to dislocation motion. Grain boundaries are widely envisaged to be mechanically static structures, but this report outlines an experimental investigation of stress-driven grain boundary migration manifested as grain growth in nanocrystalline aluminum thin films. Specimens fabricated with specially designed stress and strain concentrators are used to uncover the relative importance of these parameters on grain growth. In contrast to traditional descriptions of grain boundaries as stationary obstacles to dislocation-based plasticity, the results of this study indicate that shear stresses drive grain boundaries to move in a manner consistent with recent molecular dynamics simulations and theoretical predictions of coupled grain boundary migration.