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 glas s viscosity, Evidence has been inferred from the veined fracture surfaces a nd molten droplets reported for metallic glasses. In this work, the detaile d spatially resolved surface temperature increase and subsequent dissipatio n associated with crack tip plasticity in a Zr-Ti-Ni-Cu-Be bulk metallic gl ass 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 consist ent with thermoelastic effects.