晶体相场法模拟大角度晶界的变形过程

采用晶体相场法模拟大角度晶界在外加应力作用下的变形过程,研究外加应力方向对晶界结构及位错运动的影响.研究表明：大角度晶界在应力作用下通过改变晶界曲率和位错运动使晶界发生迁移;晶界处位错形核所需临界应变与体系所受应力方向有关,其中沿平行晶界方向比沿垂直晶界方向所需临界应变更大.研究结果揭示了晶界是位错的源和汇,不仅能够产生位错,而且能够吸收位错.

Phase Field Crystal Modeling for Deformation Process of High-angle Grain Boundaries

The deformation process of high-angle grain boundaries （GBs） under an applied stress and the influence of stress direction on dislocation movement were studied by phase field crystal mothed.The simulation results show that GBs migration occurs by changing the curvature and dislocations movement under an applied stress in high-angle GBs.The magnitude of critcal strain for dislocation nucleation at GBs is related to the direction of the operative stress,of which a larger critcal strain is needed when the stress is parallel to GBs than vertical to GBs.The simulation results reveal that GBs is the source and sink of dislocation,which can not only produce dislocation,but also absorb dislocation.