Temperature rises during strain-rate dependent avalanches in bulk metallic glasses

Abstract

Localized heating during slip avalanches is relevant to the understanding of the transition from shear banding to cracking in bulk metallic glasses (BMGs). Here we focus on the released elastic energies (incorporating the influence of machine stiffness) and avalanche durations for regularly appearing large avalanches to study the maximum temperature increases of a Zr-based BMG compressed at three strain rates of 3 × 10−5, 3 × 10−4, and 3 × 10−3 s−1. The maximum released elastic energies during slip avalanches decrease with the increase of strain rates. The durations of the avalanches are on the scale of tens of milliseconds for each strain rate. As strain rate increases, the maximum temperature rises due to shear-band slips are decreased from 2.6, 2.3 to 1.9 K. Moderate heating during the large slip avalanches for three strain rate implies that thermal softening has only a small effect on the shear-banding instability.