Diffusion in a Cu-Zr metallic glass studied by microsecond-scale molecular dynamics simulations

Abstract

Icosahedral short-range order (ISRO) has been widely accepted to be dominant in Cu-Zr metallic glasses (MGs). However, the diffusion mechanism and correlation of ISRO and medium-range order (MRO) to diffusion in MGs remain largely unexplored. Here, we perform a long time annealing up to 1.8 \ensuremath{\mu}s in molecular dynamics simulations to study the diffusion mechanism and the relationship between atomic structures and the diffusion path in a $\mathrm{C}{\mathrm{u}}_{64.5}\mathrm{Z}{\mathrm{r}}_{35.5}$ MG. It is found that most of the diffusing events performed by the diffusing atoms are outside ISRO and the Bergman-type MRO. The long-range diffusion in MGs is highly heterogeneous, via collective diffusing events through the liquidlike channels in the glass. Our results clearly demonstrate a strong correlation between the atomic structures and transport in MGs.