The near constant loss dynamic mode in metallic glass

Abstract

The near constant loss (NCL) in relaxation spectra is a crucial dynamic phenomenon for glass-forming materials, while its underlying mechanism remains unclear and is hard to study due to the absence of characteristic time scale. We define a characteristic crossover point from both the dynamic mechanical measurements and the quasi-static tension experiments in the metallic glasses (MGs), to study the transition regime, where the NCL dynamics terminates and evolves to the initiation of the β-relaxation. It is found that such transition shows an apparent activation energy well below that of the β-relaxation. Our results also show the concomitant change of the crossover points and the NCL with aging and provide a cursory physical picture on how the NCL occurs, decays and evolves to the β- and α-relaxations in MGs.