Phase-field simulation on dendritic to semi-circular morphology transition induced by forced liquid flow

A 2-D phase-field model coupling with convection is implemented to investigate the dendritic morphology evolution of the Ni–40.8%Cu alloy during solidification with forced liquid flow. Simulation results indicate that liquid flow can significantly affect the distributions of temperature and concentration near the liquid–solid interface, leading to asymmetric formation of the dendritic microstructure. Increasing the liquid flow will enhance the asymmetry of dendrite morphology with much more suppressed growth in the downstream and intensified morphology development in the upstream, leading to a dendritic to semi-circular morphology transition in the microstructure formation. Based on the simulations, it can be concluded that the morphology changes with increasing flow velocity in this study is attributed to the difference of the constitutional supercooling near the solid–liquid interfaces, which is the result of the asymmetric solute diffusion induced by the liquid flow. Therefore, controlling the liquid flow during the solidification might lead to the microstructure optimization to achieve materials with excellent properties.