Deformation behaviors under tension and compression: Atomic simulation of Cu65Zr35 metallic glass

To clarify the difference in the plasticity of metallic glasses observed experimentally under tension and compression, the changes in the structural state induced during the deformation of Cu65Zr35 glassy alloy were analyzed by means of molecular dynamics (MD) simulation. Although mechanical responses were distinct, no clear difference was detected in the change in the short-range order of the deformed structures, except for the intensive collapse of the (0,3,6,4) bonding in the elastic regime seen in the extended sample. To explain the difference in the plasticity and particularly the brittleness of bulk metallic glass (BMG) in the tensile mode, we examine the degree of strain localization and discuss the role of normal stress on the activation of shear transformation zones (STZs) during tension and compression in the elastic regime.