用分子动力学方法模拟了金属铜纳米双晶中晶界在应变作用下的迁移过程,晶界类型为<111>倾侧∑19晶界。原子间相互作用力采用F inn is-S inc lair型EAM势计算。结果表明:平行于晶界方向的压应变可以促进晶界在相邻晶界交互作用下发生迁移;垂直于晶界方向的压应变则不能对晶界迁移产生明显的效果。晶界迁移大致可分为两个阶段,前阶段晶界迁移缓慢,随晶界间距减小,晶界间交互作用加强,使晶界迁移显著加速。
Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM (embedded atom method) potential of FS type is used for calculating the interatomic forces. The results show that in nanocrystalline copper, GB migration driven by inter-GB reaction can take place. A critical grain size is identified, below which the inter-GB reaction becomes strong enough to trigger GB motion, which accelerates rapidly and leads to annihilation of the grain boundaries. The critical size is found to be 16 atomic radii. A "through intermediate grain mechanism" is identified for the nano-grain boundary motion observed, which is never reported for GB migrations of conventional polycrystalline metals.
