Combined molecular dynamics and phase field simulation investigations of crystal-melt interfacial properties and dendritic solidification of highly undercooled titanium

摘要

The effects of kinetic and capillary anisotropies on crystal morphology and growth rate during solidification of titanium are studied using atomistically-informed phase field simulations. Molecular dynamics (MD) is employed to calculate the anisotropic kinetic coefficient and crystal-melt interface free energy using the free solidification and capillary methods. The phase field simulation results for solidification velocity and interface temperature are in quantitative good agreement with experimental and analytical data for undercoolings below 150 K. As the role of interface kinetic effects increases with undercooling the use of a modified phase field model allowed the extension of its quantitative prediction capability to higher undercoolings. In addition, the effect of MD calculated kinetic and capillary anisotropy parameters on dendrite shape and tip and solidification velocity was investigated.