Time-resolved measurement of shear-band temperature during serrated flow in a Zr-based metallic glass

Severe localization of plastic flow into shear bands is typically accompanied by local heating. In metallic glasses, the small lateral extension of shear bands, the short duration of their intermittent plastic slips, and the unpredictable position of their initiation make in-situ investigations of local changes in temperature during shear banding difficult. An alternative is to estimate shear-band temperature using calculations for a given assumed deformation model, which generates predictions of temperature changes from 5 °C to more than 1000 °C. In this study we review four models of plastic slip accumulation and present first results on temporally resolved shear-band heating in metallic glasses via infrared thermography. We find that the heat evolution in a shear band during plastic slip is best modelled by shear that occurs simultaneously within serration time scales. This illustrates clearly that temperature changes within shear bands are less than 6 °C during stable plastic flow.