Phase-field simulations of non-isothermal binary alloys solidification with Neumann boundary conditions

The dendrite growth process during the non isothermal solidification of the Al-4.5%Cu binary alloy was simulated by using the phase-field model with the Neumann boundary conditions. Solute diffusion equation and heat transfer equation were solved simultaneously. The dendrite growth, solute and temperature profile in the non-isothermal solidification were investigated. The results indicate that the simulation with Neumann boundary conditions agree well with the features commonly observed in real solidification of binary alloy.The tip speed decreased and the tip radius increases at first. Then both of the tip speed and radius become larger. Finally the tip speed and radius reduce gradually over time, the solute gradients exist in the interface before the dendrite tip is the highest. The temperature in non-isothermal solidification decreases at first and then gradually increase.