Dislocation climb model based on coupling the diffusion theory of point defects with discrete dislocation dynamics

作者：Gao Yuan; Liu Zhan-Li; Zhao Xue-Chuan; Zhang Zhao-Hui; Zhuang Zhuo^*; You Xiao-Chuan

来源：Acta Physica Sinica, 2011, 60(9): 096103.

• dislocation climb
• diffusion theory of point defects
• dislocation dynamics
• prismatic dislocation loop

Dislocation climb plays a vital role in the plastic behavior of crystals at high temperatures. In order to reveal the intrinsic mechanism of climb and its effect on plasticity, a new dislocation climb model is first developed based on the combination of the diffusion theory with both bulk diffusion and pipe diffusion in a three-dimensional discrete dislocation dynamics (DDD) simulation, which is considered to be more physical and widely applicable. Using our model the shrinkage processes of a single prismatic loop group and prismatic loop group are simulated. It is concluded that the climb rate is not directly determined by mechanical climb force as believed in classical theories, but by the gradient of the vacancy concentration around (bulk diffusion) and along (pipe diffusion) the dislocation line. Loop coarsening process is also simulated, and the three pronounced evolving stages of the loop radii and the average vacancy concentrations in crystal are reproduced.

• 出版日期2011-9
• 单位清华大学