旋转晶界角对孪晶铜力学性能影响的模拟研究  

Simulations on effect of twist grain boundary angle on mechanical property of twinned copper

作　　者：邹蓉[1] 徐建刚[1] 宋海洋[1,2] 席欢[1] 李国辉[1] 

机构地区：[1]西安邮电大学理学院,陕西西安710121 [2]西安石油大学材料科学与工程学院,陕西西安710065

出　　处：《兵器材料科学与工程》2015年第5期56-60,共5页Ordnance Material Science and Engineering

基　　金：教育部新世纪优秀人才支持计划项目(NCET-12-1046);陕西省青年科技新星支持计划项目(2012KJXX-39)

摘　　要：采用分子动力学模拟方法研究了旋转晶界角对铜孪晶纳米线拉伸加载下力学性能的影响。模拟采用多体紧束缚势函数描述铜原子间的相互作用。通过模拟结果,分析了单晶铜和孪晶铜之间的差异,以及不同旋转晶界角的铜孪晶纳米线的位错成核机制。结果表明:随着旋转晶界角的增加,铜纳米线的屈服强度减弱;当旋转晶界角较小时,界面上出现了成三角形网格的失配位错,随着旋转晶界角的增大,网格逐渐缩小甚至消失;旋转晶界角较大时,晶界处易于位错成核,且界面对位错的存储能力和阻碍作用均减弱,导致屈服强度减弱。The effects of twist grain boundary angle on the mechanical behavior of twinned copper nanowires under uniform tensile loading were investigated using molecular dynamics method. In the simulation, the many- body tight- binding potential was employed to present the interaction between copper atoms. Furthermore, the differences between single-＇crystal copper and twinned copper, and the dislocation nucleation mechanism of various twist angle of the grain boundary were analyzed. Simulations indicate that the highest yield strength decreases with the increase of the twist grain boundary angle. The misfit dislocations on the interface form a triangle-latticed network when a small twist grain boundary angle is applied to the nanowires, the triangle-latticed unit of the misfit dislocations network will shrink or even disappear with the increase of the twist grain boundary. The yield strength is obviously decreased when a large twist angle of grain boundary exists. This is the main reason why the grain boundary is unstable and the formation of the dislocation nucleation is easy, in addition, the dislocation storage ability and the obstruction of the grain boundary are very weak.

关 键 词：分子动力学模拟 铜孪晶纳米线 旋转晶界角 失配位错 力学性能 

分 类 号：O411.3[理学—理论物理]