Simulation of binary alloy free dendritic growth with a phase-field model

Free dendritic growth of dilute binary alloys into a supercooled melt is simulated using a two-dimensional phase-field model. The model accounts for coupled heat and solute transport in the melt and allows simulations to be performed in. a thin-interface limit, with a vanishing kinetic effect and no solute trapping. An adaptive grid that permits calculations for large ratios of thermal to solutal diffusivity (Lewis number) is used. Good agreement between numerically predicted and theoretical values of growth Peclet numbers is obtained. The selection parameter sigma* is shown to vary with initial melt concentration, Lewis number, and imposed supercooling.