Strain rate effects on the yielding strength and maximum temperature at shear bands in a Zr-based bulk metallic glass

The effects of strain rate on the yielding strength and maximum temperature at shear bands in a typical Zr41.2Ti13.8Ni10Cu12.5Be22.5 (Vit 1) bulk metallic glass are investigated under tension and compression over a wide range of strain rates at ambient temperature. Using the modified cooperative shear model incorporating the notable internal thermal effect at high strain rates, the transition of the strain rate effect of yielding strength from the sudden decrease to the subsequent slow change with increasing the strain rate is quantitatively characterized. The fracture surface temperature evolution under different shear band evolution times is captured by a hierarchical multi-scale model of heat conduction. Dynamic strain rates shorten the shear band evolution time, leading to an increase in the maximum temperature at shear bands compared to quasi-static loadings.