Stochastic dislocation dynamics for dislocation-defects interaction: A multiscale modeling approach
Stochastic dislocation dynamics for dislocation-defects interaction: A multiscale modeling approach
复制标题
位错-缺陷相互作用的随机位错动力学：多尺度建模方法
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
H. Zbib
中科院分区：
文献类型：
--
作者：
M. Hiratani;H. Zbib
建立了一个随机位错动力学（SDD）模型来研究位错通过扩散障碍的逃逸。该模型考虑到：1）用离散位错动力学研究了不同的dray机制下亚稳位错之间的飞行动力学; 2）用随机力研究了亚稳钉扎位错的热激活过程。这两个过程的整合允许一个检查障碍物控制的运动和阻力控制的运动之间的位错运动的瞬态制度。得到了与铜的应力-应变率行为有关的结果。平均位错速度的应力和温度依赖性显示障碍控制区低于临界分辨剪切应力（CRSS）和阻力控制区以上的CRSS，这是在很好的定性与实验数据。在CRSS正下方的瞬态区，由于位错飞行过程和热激活过程中的拖曳效应之间的竞争，观察到负的温度敏感性。
A stochastic dislocation dynamics (SDD) model is developed to investigate dislocation elide through dispersal obstacles. The model accounts for: 1) the dynamics of the flight process between successive meta-stable dislocations under various dray mechanism using discrete dislocation dynamics, and 2) thermal activation processes for meta-stable pinned dislocations using a stochastic force. The integration of the two processes allows one to examine the transient regime of dislocation motion between obstacle-controlled motion and drag-controlled motion. Result pertaining to the stress-strain rate behavior in copper are obtained. The stress and temperature dependence of the average dislocation velocity show obstacle-controlled region below the critical resolved shear stress (CRSS) and drag controlled region above the CRSS, which is in good qualitative agreement with experimental data. In the transient region right below the CRSS, negative temperature sensitivity is observed due to the competition between the drag effects in dislocation flight process and thermal activation process.