Serrated flow and shear band evolution in a Zr-based bulk metallic glass after plastic deformation and annealing

The effect of pre-deformation and annealing on serrated plastic flow and shear band features of a Zr-based bulk metallic glass was investigated through nanoindentation and macroindentation tests. The results showed that the serrated plastic flow during the loading process of nanoindentation was significantly suppressed in pre-deformed sample and re-appeared after subsequent annealing. The effect of pre-existed shear bands on the development of final shear bands was characterized by macroindentation without bonded interfaces. Pre-deformation does not lead to the multiply of shear band during the consequent plastic deformation, but decrease the shear band number significantly. The change in plastic flow behavior of the alloy by pre-deformation is thought to be the preferential propagation of existed shear bands, and its effect can be eliminated by annealing below glass transition temperature.