Calorimetric study of beta-relaxation in an amorphous alloy: An experimental technique for measuring the activation energy for shear transformation

Abstract

When loaded at cryogenic temperature under stresses below the global yield, an amorphous alloy revealed two clearly distinguishable exothermic events during heating in calorimetric experiments. These exotherms, commonly known as the alpha- and beta-relaxations, were attributed to the annealing out of two different local structures with different structural stability, presumably free volume and shear transformation zone (STZ). In this study, we introduced a simple and reliable experimental technique, which enables the evaluation of the activation energy corresponding to the beta-relaxation, E-beta. Based on experimental evidence and comparison with earlier studies, it is presumed that E-beta is directly related to the potential energy barrier to shear transformation. (C) 2013 Published by Elsevier Ltd.