Solid-liquid interfacial properties of refractory metals from atomistic simulations

In this work, we use molecular dynamics simulations to compute anisotropic solid-liquid interfacial properties for refractory metals Mo, Nb, Ta, V and W using an accurate tabulated Gaussian approximation potential. The capillary fluctuation method is used for calculating the anisotropic solid-liquid interfacial free energy, and non-equilibrium free solidification simulations are used for estimating the kinetic coefficient and its anisotropy. A layered thermostat approach is used for the non-equilibrium simulations, and the number of thermostats required to maintain isothermal solidification conditions is discussed. We find that the anisotropy of the solid-liquid interfacial free energies and kinetic coefficients is weak but follows consistently ordering 100 > 110. Additionally, we compute the self-diffusivities of the liquid metals and their temperature dependence.