Molecular dynamics simulations of diffusion in Cu-Zr alloys in their liquid and supercooled liquid states were performed by using a recently developed Finnis-Sinclair many-body interatomic potential. To help to assess how well the interatomic potential described the energetics of the Cu-Zr system, the liquid structure determined by molecular dynamics simulations was compared with wide-angle X-ray scattering measurements of the liquid structure for a Cu64.5Zr35.5 alloy. Diffusion was examined as a function of composition, pressure and temperature. The simulations revealed that the diffusion exhibited a strong compositional dependence, with both species exhibiting minimum diffusivities at ∼70%Cu. Moreover, the molecular dynamics simulations showed that the activation volumes for Zr and Cu atoms exhibited a maximum near to 70% Cu. Evidence was obtained showing that the glass transition temperature also changed strongly with composition, thereby contributing to the diffusion behaviour. The relationship between this minimum in diffusion and the apparent best glass-forming composition in the Cu-Zr system was considered.

Molecular Dynamics Simulation of Diffusion in Supercooled Cu-Zr Alloys. M.I.Mendelev, M.J.Kramer, R.T.Ott, D.J.Sordelet: Philosophical Magazine, 2009, 89[2], 109-26