基于多尺度模拟研究Ni/Cu薄膜压痕塑性的原子机制

基于准连续介质多尺度模拟方法研究了Ni/Cu双层薄膜初始压痕塑性的原子机制,结果主要包括:(1)当Ni晶体层厚度小于10nm时,随着Ni晶体层厚度的减少,薄膜弹性极限所对应的临界接触力逐渐降低,即Ni/Cu薄膜随Ni晶体层厚度减小而变软;(2)压头下方晶格Shockley分位错的开动、界面位错的分解、以及界面位错与晶格位错的相互作用是Ni/Cu薄膜初始塑性的微观原子机制,(3)根据模拟结果观察和位错弹性理论计算,承载初始塑性的界面位错数目变少是Ni/Cu薄膜软化的主要原子机制.本文研究结果能够为异质界面力学行为研究提供有益参考.

Atomistic mechanisms of the incipient plasticity of nano-indented Ni/Cu films via multi-scale simulations

The atomistic mechanisms of the incipient plasticity of nano-indented Ni/Cu bi-layer films were studied by using the quasicontinuum multi-scale simulations. Results show that (1) the critical contact force under elastic limit condition decreases with the thickness of Ni layer, when the thickness of Ni layer is less than 10 nm, there is a weakening effect of Ni/Cu films: (2) the operation of Shockley partial dislocation, disassociation of interface dislocation, and interactions between interface dislocations and lattice dislocations are the main mechanisms of the incipient plasticity of Ni/Cu films; (3) decreasing of the amount of activated interface dislocations is the main reason for the weakening of Ni/Cu films, based on further defect structure observations and theoretical calculations. Studies on the mechanical behavior of heterogeneous interfaces can be benefit from the present research results.