界面旋转角对双晶镁力学性质影响的分子动力学模拟

Molecular dynamics simulation of effect of tilt angle on mechanical property of magnesium bicrystals

采用分子动力学模拟方法,研究了在拉伸载荷下晶界对双晶镁变形机制的影响,对不同旋转角度的模型以及对称与非对称结构的模型进行了研究.模拟结果表明:应变加载方向与晶向所成角度对双晶镁塑形变形阶段的流动应力能够产生明显的影响;对称结构的双晶镁模型的塑性性质明显优于非对称结构模型.研究结果还发现,由于晶界区域不同的位错成核及发射等运动,大角度双晶模型的塑性响应明显优于对应小角度模型的塑性响应.

The effects of grain boundary on the deformation behavior of magnesium bicrystals under tensile loading are investigated using molecular dynamics simulation method. Deformation mechanisms of both asymmetric and symmetric magnesium bicrystals are studied. The results show that the twist angle could exert a significant influence on the flow stress in the plastic stage. It is found that the plastic property of symmetric magnesium bicrystal is much better than that of asymmetric counterpart. In addition, for bicrystalline metal with large twist angle, its plastic response is better than that with small angle, owing to the dislocation nucleation activity in the grain boundary region.