Rejuvenation of La-based metallic glass by controlling different modes of relaxation

Abstract

Metallic glasses (MGs) have multiple dynamic relaxation modes, among which α and β relaxations are two typical modes. The rejuvenation of MGs usually refers to the increase in the total enthalpy of structural relaxation. However, the control mechanism of single-mode relaxation and the contributions of different relaxation modes to the total enthalpy are still unclear. We investigated the effects of stress, temperature and their coupling fields on α and β relaxations through experimental and molecular dynamics (MD) simulations. We found that the temperature field activated more sites for β relaxation, while the prolonged stress leads to the aggregations and connections of a quantity of localized atomic clusters and even activates α relaxation. The coupled field integrates the characteristics of stress and temperature fields and results in a clear splitting of α and β relaxations. Our work provides useful insights into the single-mode regulation of α and β relaxations in MGs.