Simulation Of Dendritic Growth During Multicomponent Alloy Solidification With A Front-Tracking Method

A front-tracking solidification model has been developed to simulate the dendritic structure evolution during multi-component alloy solidification. In the model, the growth of dendrites is governed by heat and mass transport, where a finite difference technique is employed to solve heat and solute diffusion during the solidification. The model incorporates front-tracking technique to calculate and track the exact position of the Solid/Liquid (S/L) interface as a part of solution process and a new capture rule was designed and implemented in the model to efficiently track the growing S/L interface.The solidification of Al-Si-Cu alloy is studied, based on which the front-tracking model has been developed. Research results reveal that solute redistribution and curvature of the S/L curvature undercooling are important factors in determining the dendritic morphology. Based the above study, the ternary front-tracking model is developed to simulate microstructure during solidification.Simulations of solidification are performed using the developed model for single-grain and multi-grain dendrite growth during solidification. Single -grain dendrite growth under various undercoolings and cooling rates are calculated. Dendritic morphology under different undercoolings and cooling rates are compared. During the multi-grain growth simulation, the solidification segregation is investigated. Meanwhile, the dendritic evolution and solute interaction during multi-grain growth are investigated.In this thesis, the microstructure evolution during multi-component solidification has been simulated using the developed front-tracking model. The simulation results show that the various phenomena, which are consistent with the classical solidification theory, are reproduced. This suggests that the front-tracking model can simulate correctly the growth of dendrites.