Local heating associated with crack tip plasticity in Zr-Ti-Ni-Cu-Be bulk amorphous metals

Deformation in metallic glasses is generally considered to arise from flow in localized shear bands, where adiabatic heating is thought to reduce glass viscosity. Evidence has been inferred from the veined fracture surfaces and molten droplets reported for metallic glasses. In this work, the detailed spatially resolved surface temperature increase and subsequent dissipation associated with crack tip plasticity in a Zr-Ti-Ni-Cu-Be bulk metallic glass is characterized for the first time. Maximum temperatures of up to 54.2 K were estimated from a heat conduction model and shown to be in excellent agreement with a nonhardening plasticity model for the heat generated by a propagating crack. Local cooling was also observed and shown to be consistent with thermoelastic effects.