Phase Field Method Simulation Of Microstructure Evolution During Solidification

The simulation of microstructure evolution during solidification has experienced deterministic method, stochastic method and phase field method. Phase field method is the newest method and it can simulate the growth of dendritic crystal. Phase field method is an effective tool to describe the complicate solid-liquid interface in non-equilibrium state. Without explicitly tracking the complex phase boundaries, it is expected to simulate the complex dendritic growth during the solidification processes.Taking Al-2-mole-%-Si alloy for example, this work aimed at simulating multiple grains growth and oriented growth during solidification by using phase-field method. The effect of model parameters on dendrite morphology was studied. The main contents are as follows:1. The dendritic growth of multiple grains of Al-2-mole-%-Si alloy during the solidification processes was simulated. Dendrite morphology of multiple branches was obtained. The arbitrarily oriented crystals grow freely in undercooled melt. Eventually, gains impinge against each other. The competitive growth of grains, ripen, coalescence and solute microsegregation in the dendritic growth are realized.2. The solute distribution of dendritic growth of multiple grains of Al-2-mole-%-Si alloy during the solidification processes was predicted. When the diffusion field of dendrite tip encounter diffusion field of dendritic branch growth from adjacent dendrite, the dendrites then stop growing.3. The influence of different anisotropy coefficients, disturbance intension, interface thickness and undercooling on dendrite morphology and distribution of solute for grains were studied.4. Oriented growth of single grain of Al-2-mole-%-Si alloy during the solidification processes was simulated. Not only the process of dendritic growth during solidification is reappearing, but also the asymmetry phenomenon is found in the secondary and tertiary arms. The side branching occurs only at one side of the arms, which are consistent to experiments made by Clicksman.