Flow serrations and fracture morphologies of Cu-based bulk metallic glasses in energy release perspective

Flow serrations and fracture morphologies of a Cu50Zr43Al7 bulk metallic glass (BMG) compressed at a low strain rate were analyzed in an energy release perspective. The energy release at failure was estimated to be about two orders of magnitude larger than those in the serrated region. During consecutive propagation of a shear band, the temperature rise is estimated to be only a few degrees Kelvin, which eventually causes the intermittent shear region with regularly spaced striations on the fracture surface. The temperature rise of several-hundred degrees Kelvin caused by the high accumulated fracture energy release upon failure is sufficiently high to result in the viscosity drop within a propagating shear band and may lead to local melting on the separated surface.