The dependence of shear modulus on dynamic relaxation and evolution of local structural heterogeneity in a metallic glass

Starting from the nanoscale structural heterogeneities intrinsic to metallic glasses (MGs), here we show that there are two concurrent contributions to their microscale quasi-static shear modulus G_I: one (μ) is related to the atomic bonding strength of solid-like regions and the other (G_II) to the change in the possible configurations of liquid-like regions (dynamic relaxation). Through carefully designed high-rate nanoscale indentation tests, a simple constitutive relation (μ = G_I + G _II) is experimentally verified. On a fundamental level, our current work provides a structure-property correlation that may be applicable to a wide range of glassy materials. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.