Structural rejuvenation and relaxation of a metallic glass under the periodically thermal-mechanical loading

Abstract

The current work focuses on effect of the thermomechanical protocol which can lead either to aging or rejuvenation of glass through decoupling of the thermal and mechanical processes. We demonstrated that the La-based metallic glass shows a kind of material hypomnesia because a clearer rejuvenation trend is observed just after imposing strain oscillations of increasing amplitude than after a long period from that, as it is proved by the results of stress relaxation. There is a threshold value of the oscillation amplitude that separates the effect of the protocol between acceleration of aging and rejuvenation. The activated energy spectrums imply plasticity and mechanical heterogeneity of the metallic glass promoted by simple mechanical stimulation. Mechanical perturbations applied not long ago in time are vital for hypomnesia metallic glasses, in which different histories lead to various degrees of aging or rejuvenation. The correlation between the thermomechanical properties of metallic glasses and the previous application of strain oscillations of various amplitude is unveiled in this work, revealing an effective tool for regulating the structural state of metallic glasses through an easy-operated method.