含界面效应纳米尺度圆环形涂层中螺型位错分析

ELASTIC ANALYSIS OF A SCREW DISLOCATION IN AN ANNULAR COATING LAYER WITH INTERFACE STRESSES

研究了纳米尺度圆环形涂层(界面层)中螺型位错与圆形夹杂以及无限大基体材料的干涉效应.涂层与夹杂的界面和涂层与基体的界面均考虑界面应力效应.运用复势方法,获得了三个区域复势函数的解析解答.利用求得的应力场和Peach-Koehler公式,得到了作用在螺型位错上位错力的精确表达式.主要讨论了界面应力对涂层(界面层)中螺型位错运动和平衡稳定的影响规律.结果表明,界面应力对界面附近位错的运动有大的影响,由于界面应力的存在,可以改变涂层内位错与夹杂/基体干涉的引斥规律,并使位错在涂层内部产生三个稳定或非稳定的平衡点.考虑界面效应后,有一个额外的排斥力或吸引力作用在位错上,使原有的位错力增加或减小.

The interaction between a screw dislocation which locates in the nanoscale coating layer（interphase layer） with interface stresses and the circular particle and matrix is investigated.The analytical solutions of complex potential functions in the particle,the coating layer and the infinite matrix are derived by means of the complex variable method.With the aid of the Peach-Koehler formula,the explicit expression of the image force acting on the screw dislocation is given.The influence of the interface stresses on the image force and the equilibrium position of the dislocation in the coating layer（interphase layer） is carefully discussed.The results show that the influence of the interface stresses on the motion of the dislocation near the interfaces is very significant.Under some conditions,the presence of the interface stress can change the interaction mechanism between the screw dislocation and particle/matrix,and three equilibrium positions can exist for the dislocation in the coating layer.It can be seen that an additional repulsive force or attractive force will act on the dislocation for considering the interface effect,which cause the image force to increase or decrease.