Atomic dynamics transition in a Cu-Zr-Al metallic glass

Abstract

We reveal a slow-to-fast dynamics transition in the as-cast Cu46Zr46Al8 (at.%) metallic glass (MG) at a temperature below the glass transition upon heating, which depends on the competition between free volume annihilation and thermally-activated atomic mobility, well consistent with the bond-length change of Cu-Cu pairs. The activation of α-relaxation at high temperatures could be related to the bond-length extension of Cu-Cu and Zr-Zr like-atom pairs together with the shortening of Cu-Zr unlike-atom pairs. Our results provide new insights into the correlation of dynamics with atomic structure in MGs and will be helpful to the understanding of ageing behaviors in MGs.