EFFECT OF SHRINKAGE ON Al−Si ALLOY SOLIDIFICATION

Two dimensional, transient fluid flow induced by density difference between solid and liquid during downward solidification of Aluminum − Silicon (Al-Si) alloy was simulated. The solidification process was carried out inside a cylindrical container. Effect of shrinkage on solidification time, temperature distribution and fluid flow was investigated. Mass conservation, momentum, energy, and concentration equations were coupled and solved iteratively using an implicit numerical algorithm based on the finite - volume method. Local thermal dynamic equilibrium assumption was employed to establish relationship between temperature and liquid concentration inside the mushy zone. Numerical results have been verified and found in good agreement with experimental data. Shrinkage was found to increase local temperatures during solidification and hence resulted in increase of solidification time. Numerical simulation indicated that flow velocity was increased and direction was changed with the consideration of shrinkage during solidification.