非对称倾侧亚晶界的晶体相场法研究

Phase field crystal study on asymmetrical tilt subgrain boundaries

采用晶体相场法研究非对称倾侧亚晶界结构及其在应力作用下的微观运动机制.分别从温度、倾斜度角以及应力施加方向等方面对其结构及迁移过程进行分析和讨论.结果表明,非对称倾侧亚晶界由符号相同的一排刃型位错等距排列,部分出现由两个相互垂直排列的刃型位错构成的位错组;在应力作用下,非对称倾侧亚晶界迁移的微观机制包括位错的滑移和攀移、位错组分解、单个位错与位错组反应、单个位错分解以及位错湮灭;温度降低和倾斜度增大都会阻碍亚晶界的迁移过程;应力方向改变导致位错运动方向改变,从而改变晶界迁移形式.

With the phase field crystal approach, the structure of asymmetrical tilt subgrain boundaries and their motion micmechanism under stress are studied. The effects of temperature, inclination angle and stress direction on structure and migration process are also analyzed and discussed. Simulated results show that the subgrain boundary is composed of a row of edge dislcations with the same bugers vectors and the double-array dislocations with a vertical distribution. The motion process of asymmetrical tilt subgrain boundaries contains dislocation glide and climb, dislocation separation, dislocation reaction, individual dislocation decomposition and dislocation annihilation. The decrease of temperature and the increase of inclination angle hinder the subgrain boundary migration process. The change of stress direction causes the variation of dislocation motion and thus lead to the change in migration manner of subgrain boundary.