Deformation-induced change in the structure of metallic glasses during multistep indentation

The perplexing controversy of whether deformation-induced hardening/softening is intrinsic or extrinsic remains an outstanding fundamental problem in the low-temperature rheology and dynamics of metallic glasses. In this Brief Report, by manipulating nanoscale plastic deformation in a multistep instrumented indentation process, we in situ characterize and definitively elucidate the deformation-driven structural changes in metallic glasses via their strengthening or softening effect on consecutive mechanical behavior.