The relationship between static structure and dynamics as measured through the diffusion coefficients in viscous multicomponent metallic melts was elucidated by the example of the binary alloy Zr64Ni36, by a combination of neutron-scattering experiments and mode-coupling theory of the glass transition. Comparison with a hard-sphere mixture showed that the relation between the different self diffusion coefficients strongly depended upon chemical short-range ordering. For the Zr-Ni example, the theory predicted both diffusivities to be practically identical. The kinetics of concentration fluctuations was dramatically slower than that of self-diffusion, but the overall interdiffusion coefficient was equally large or larger due to a purely thermodynamic prefactor. This result was a general feature for non-demixing dense melts, irrespective 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[6], 66001 (6pp)

Table 7

Diffusion Parameters for H in Zr-Mn-Fe-Ni-Cr-V Alloys