Propagation of shear bands in metallic glasses and transition from serrated to non-serrated plastic flow at low temperatures

The mechanical behavior and the kinetics of shear banding in bulk metallic glasses was investigated at room and liquid nitrogen temperature using the acoustic emission (AE) technique. It was demonstrated that the intensive AE reflecting the activity of strongly localized shear bands at room temperature vanishes at the transition of plastic flow from serrated to non-serrated with a reduction in temperature. The disappearance of AE clearly suggests that the shear band propagation velocity significantly decreases at low temperature, and sliding along the principle shear band is observed at the machine-driven rate.