Propagation of shear bands in a Cu_47.5Zr_47.5 Al₅ bulk metallic glass

We report a novel finding of slither propagation of shear bands on the fracture surface of a Cu_47.5Zr_47.5Al₅ bulk metallic glass (BMG). The nanoscale heterogeneities in the as-cast state are aggregated along shear bands with irregular morphology. Such heterogeneities create a fluctuating stress field during shear band propagation leading to a slither propagation mode. The slither propagation of 10 to 15 nm wide shear bands is effective to improve both the plasticity and the "work-hardening-like" behavior of BMGs if the size, the morphology, and the elastic properties of the heterogeneities are intimately intercalated during solidification.