MODELING THE EFFECT OF EUTECTIC NUCLEATION BEHAVIOR ON PERMEBILITY DURING SOLIDIFICATION OF Al-19.5wtCu

摘要

The nucleation behavior of eutectic phase and the resulting distribution of eutectic colonies within the mushy zone can have a significant influence on interdendritic permeability. Therefore, it will also significantly affect the amount and distribution of feeding related defects. In the present study, 3D geometry of eutectic/primary phases obtained by X-ray microtomography (XMT) has been used to generate a computational domain in which the eutectic transformation takes place. By applying conventional theory of eutectic nucleation and the Monte Carlo technique for simulating the growth of eutectic colonies, the evolution of interdendritic channels has been modeled. The mushy zone permeability during eutectic evolution has then been calculated by solving the full Navier-Stokes equation on the evolving microstructures. The calculated permeability shows the impact of the eutectic solidification behavior as it deviates from traditional Carman-Kozeny expression of permeability.