Cu／Ni多层膜强化机理的分子动力学模拟

MOLECULAR DYNAMICS SIMULATION OF STRENGTHENING MECHANISM OF Cu/Ni MULTILAYERS

运用分子动力学方法模拟了Cu/Ni薄膜结构在纳米压入和微摩擦过程位错的运动规律,探讨了薄膜结构中位错与界面的相互作用规律.结果表明:Cu/Ni多层膜结构中的层间界面会阻碍位错继续向材料内部扩展,阻碍作用主要来自于两个方面:界面失配位错网对位错运动的排斥阻力使其难以到达或穿过界面;由弹性模量差而产生的界面镜像力使位错被限制在Cu单层膜内运动.这种阻碍作用有利于提高Cu/Ni多层薄膜的力学性能.

The movement of glide dislocations in Cu/Ni films during nano indentation and friction was simulated by using 3D and 2D molecular dynamics methods respectively, and the interactions between interface and glide dislocations were analyzed. The results show that the repulsive force produced by the misfit dislocation network at the interface prevents the glide dislocations accessing or passing through the interfaces; the image force arising from the modulus difference across an interface confines the glide dislocations to move within Cu individual layer. Both of the above forces can be used to explain the strengthening mechanism of Cu/Ni multilayers.