Molecular dynamics study of deformation behavior of crystalline Cu/amorphous Cu50Zr50 nanolaminates

Abstract

Crystalline/amorphous (C/A) metallic nanolaminates have been increasingly studied due to its excellent mechanical behaviors. Here, the effects of layer thickness and sample size on the deformation behavior of C/A Cu/CuZr nanolaminates under tension loading are investigated using molecular dynamics simulation method. For nanolaminates with equal layer thickness of crystalline and amorphous, a transition in the plastic deformation mode takes place in the C/A nanolaminates from homogeneous plastic co-deformation between interfacial dislocation and shear transformation zones to multiple shear bands interaction. For the nanolaminates with fixed amorphous layer, the peak stress decreases with the decreasing crystalline layer thickness, consisting with the results calculated by the mixed rule. However, when crystalline layer thickness is >5nm, the peak stress reaches a plateau, which can be well-explained by the confined layer slip model. In addition, the results indicate that the plastic deformation behavior of nanolaminates transits from global plastic deformation to local plastic deformation with decreasing aspect ratio.