From elastic excitations to macroscopic plasticity in metallic glasses

Abstract

Shear transformation zone (STZ) remains the fundamental unit to explain plastic flow in metallic glasses (MGs). Although STZs have been known and characterized for decades now the morphological and dynamical characteristics of STZs are not fully understood yet. Here, simulating athermal quasistatic shearing processes, the atomic-level mechanisms underlying elastic and plastic deformation in MGs are disclosed. Given the highly heterogeneous nature of glassy materials and the related rugged energy landscape the activation of STZs is observed from an early level of elastic deformation until the final shearing stage. The STZs identified within the elastic and plastic ranges have similar fingerprints but different magnitude and dynamics. Long-range overlapping STZ fields constrain atomic rearrangements and limit quantifying structure-dynamics correlations that explains the difficulty in establishing an ideal structure-property relationships for MGs.