Revealing localized plastic flow in apparent elastic region before yielding in metallic glasses

Abstract

The microscopically localized flow before yielding in metallic glass (MG) is hard to be detected using conventional mechanical tests due to its extremely slow process with a long time scale and lack of structural information. We present a stress relaxation approach to circumvent the experimental problem and to reveal the evolution of the flow before yielding in MG by detecting the evolution of structural heterogeneity and activation energy barrier spectra of flow units. We report on explicit correlations among dynamical heterogeneities, nanoscale flow units, and yielding, revealing a transition from the microscopically flow to macroscopic yielding in MG.