Coupling effects of thickness and aspect ratio on deformation behavior of Cu50Zr50 metallic glass

Abstract

The coupling effects of sample thickness and aspect ratio on the mechanical properties of Cu50Zr50 metallic glasses (MGs) under tensile loading are systematically investigated using molecular dynamics simulation method. The results show that for MGs with various thicknesses, there exist different critical values of aspect ratio that separate the samples into two types with different deformation behavior, above which shear bands propagation is unstable and MGs exhibit catastrophic failure, while below which it is slow and stable homogeneous flow. It is found that in homogeneous plastic flow region, the MGs show nearly perfect plasticity. However, in the catastrophic failure region, the MG fails by necking or dominant SBs slip. In addition, the results indicate that in the critical region, the critical value of aspect ratio transition from initial rapidly decline to a gradual and smooth with increasing thickness, and the 5.6nm-thick is the transition point.