The effect of wettability on gas porosity formation during directional solidification of alloys: Insights from lattice Boltzmann-cellular automata simulations

The wettability between solid and porosity plays an important role in the growth of dendrites and pore morphology during solidification of alloys. In this original article we use a two-dimensional coupled lattice Boltzmann-cellular automata-finite-difference (LB-CA-FD) model to simulate the effect of wettability on the dendritic and pore morphologies. Wettability can be adjusted by adjusting the fluid-solid interaction coefficient. The predicted results show that the wettability can strongly influence the formation of the dendritic and bubble structures. The solid-gas coupled growth occurs for the poor wettability, while the bubbles are engulfed by the growing dendrite for the good wettability. It can be found that the cooling rate can strongly affect the area ratio of the preexisting bubbles although it has little effect on the morphologies of the bubbles and dendritic structures. Moreover, morphological evolution of multidendritic growth encountering multiple bubbles during directional solidification is also investigated.