Temperature effects on the structural evolution and diffusivity of Cu60Zr40 in the liquid and glassy states were studied by molecular dynamics simulations using the Finnis–Sinclair potential. The pair distribution functions and common-neighbour analysis were used to investigate the structural variations. It was found that the amount of pentagonal bipyramids increases sharply in a short temperature range of about 200K above the glass transition temperature Tg, leading to the increasing of the icosahedral cluster centered by Cu atom and larger Kasper polyhedral cluster centered by Zr atom. The mean square displacement and the self part of the van Hove function were calculated to evaluate the relaxation and transport properties. The cage effect was found to appear at 1100K. The mode-coupling theory equation was more suitable than the Vogel–Fulcher–Tammann equation to describe the change in diffusivity in the liquid state. The critical temperature Tc, a predicted glass transition temperature in mode-coupling theory, for Cu60Zr40 glass former was 1008.2K. At temperatures near Tc, there was a dynamic crossover. In supercooled liquid state, the dynamic heterogeneity was detected. The comparison of the activation enthalpies of the two components shows that the small atoms transport faster obeying the size effect.

Atomic Structure and Diffusion in Cu60Zr40 Metallic Liquid and Glass - Molecular Dynamics Simulations. Y.L.Sun, J.Shen, A.A.Valladares: Journal of Applied Physics, 2009, 106[7], 073520