On the role of entropy in determining transport properties in metallic melts

Abstract

We performed ab initio molecular dynamics simulations to study the relationship between dynamic and structural properties of liquid Al1−xNix alloys along the T = 1795 K isotherm. Our findings show a strong non-linear dependence of self-diffusion coefficients and the viscosity as a function of composition, in fair agreement with available experimental data. We demonstrate that this non-linear dependence can be related to the detailed description of local structural ordering and more particularly to a pronounced increase of icosahedral short range order (ISRO) in the Ni-rich composition range. We evidence that the composition dependence of local structural ordering is not captured by the Stokes–Einstein relation but can be understood in terms of the partial excess entropy approximated by the two-body contribution.