The relationship between static structure and dynamics, as deduced from the diffusion coefficients in viscous multi-component metallic melts, was considered for the example of Zr64Ni36 by using a combination of neutron-scattering experiments and the mode-coupling theory of the glass transition. Comparison with a hard-sphere mixture showed that the relationship between the various self-diffusion coefficients depended strongly upon the chemical short-range order. For the Zr-Ni example, theory predicted that both diffusivities would be essentially identical. The kinetics of the concentration fluctuations were markedly slower than that of self-diffusion, but the overall interdiffusion coefficient was equally large, or larger, due to a purely thermodynamic pre-factor. This observation was a general feature of non-demixing dense melts; regardless of chemical short-range order.

Atomic Diffusion Mechanisms in a Binary Metallic Melt. T.Voigtmann, A.Meyer, D.Holland-Moritz, S.Stüber, T.Hansen, T.Unruh: EPL, 2008, 82, 66001