Short-range structural signature of transport properties of Al-Ni melts

Ab initio molecular dynamics simulations are performed to investigate dynamic properties of Al-Ni melts. Along the T = 1795 K isotherm, we show that self-diffusion coefficients and the viscosity exhibit a strong non-linear dependence as a function of composition. We further demonstrate that this behavior has an underlying origin in the composition-dependent local structural ordering characterized by a strong interplay between icosahedral short-range order and chemical short-range order in the Ni-rich composition range. Finally we evidence that this structural evolution is at the origin of the breakdown of the Stokes-Einstein relation.