Optimum Shear Stability at Intermittent-to-Smooth Transition of Plastic Flow in Metallic Glasses at Cryogenic Temperatures

Abstract

The runaway instability of shear bands leads to catastrophic failure of metallic glasses while the links between the shear banding process and the macroscopic plasticity in a quantitative manner in metallic glasses remains a major challenge.Through a series of compression tests at cryogenic temperatures, we found that the plasticity of the metallic glass can attain a maximum value at a critical temperature at which the transition from serrated flow to non-serrated flow occurs on a Zr-based metallic glass at cryogenic temperatures. The transition point corresponds to the lowest shear-band velocity and the most stable state of plastic shearing during deformation. The results provides an insight for understanding the temperature-dependent plasticity of metallic glasses from shear-band dynamics and may help to design the plasticity/ductility of metallic glasses at cryogenic temperatures.

Keywords: Metallic glass, Plasticity, Serrated flow, Brittle-ductile transition