Temperature and strain-rate dependence of surface dislocation nucleation
Temperature and strain-rate dependence of surface dislocation nucleation
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DOI：
10.1103/physrevlett.100.025502
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发表时间：
2008-01-18
影响因子：
8.6
通讯作者：
Gall, Ken
中科院分区：
文献类型：
--
作者：
Zhu, Ting;Li, Ju;Gall, Ken
位错形核是小体积晶态固体塑性变形的关键。自由表面可以作为位错的有效来源，以启动和维持塑性流动，与体源相结合。在这里，我们开发了一个原子模拟框架来处理表面位错成核的概率性质。结果表明，与表面位错成核有关的激活体积在1-10b(3)的范围内，其中b是Burgers矢量。如此小的激活体积导致了形核应力与温度和应变率的敏感关系，从而为纳米管压缩实验中的尺寸-强度关系提供了一个上限。
Dislocation nucleation is essential to the plastic deformation of small-volume crystalline solids. The free surface may act as an effective source of dislocations to initiate and sustain plastic flow, in conjunction with bulk sources. Here, we develop an atomistic modeling framework to address the probabilistic nature of surface dislocation nucleation. We show the activation volume associated with surface dislocation nucleation is characteristically in the range of 1-10b(3), where b is the Burgers vector. Such small activation volume leads to sensitive temperature and strain-rate dependence of the nucleation stress, providing an upper bound to the size-strength relation in nanopillar compression experiments.