Simulation of Dendritic Morphology and Constituent Distribution of Al-4.7%Cu Alloy Under Convection

A new two-dimensional modeling approach combining the cellular automaton(CA) and the lattice Boltzmann model(LBM) was developed to simulate heat transport, fluid flow, solute diffusion, and dendritic growth in the process of the Al-4.7%Cu solidification of the single-phase solid solution alloy. And the changes of dendritic morphology and constituent under convection were analyzed. The present model improved the solutal distribution approach at the solid-liquid (S/L) interface, which made the change of solute more consistent with the actual transport. The simulation results demonstrate that dendritic morphology is strongly influenced by forced convection, comparing with that without accounting for convection. Under the forced convection, the dendrite grain sizes tend to be similar; the constituent in the interdendritic region is more homogeneous; and the composition in the whole solidification region exhibits a certain gradient trend from upstream to downstream.