Merging of the alpha and beta relaxations and aging via the Johari-Goldstein modes in rapidly quenched metallic glasses

Abstract

This paper provides evidence that the physical aging of deeply and rapidly quenched metallic glasses is promoted by the Johari-Goldstein slow beta relaxation, resulting in a significant irreversible increase in the mechanical modulus on initial heating. Dynamic mechanical analysis has been used to characterize relaxation phenomena of a strong and a fragile metallic glass. In addition, we can extrapolate the temperature dependence of beta- and alpha-relaxation peaks to higher temperatures and calculate the merging temperature for both types of glasses. (C) 2008 American Institute of Physics.