Effect of Convection on Equiaxed Solidification of Ni-based alloy

Abstract

It has been found that the crystal morphology during equiaxed solidification can be strongly changed by the applied physical fields, such as the electromagnetic field, ultrasonic treatment or mechanical stirring. Theoretically, the applied external fields cause melt flow to impact the crystal growth and thus change the solidification structure. However, the previous relevant works mainly focused on obtaining grain refinement rather than studying the crystal morphology evolution. To study the equiaxed solidification under forced convection, the crystal growth in multidirectional flow was numerically simulated in the present work. The simulation results indicate the flow direction of forced convection strongly impacts the crystal growth and the morphology evolution. The multidirectional flow would cause much different conditions during the equiaxed solidification, which eventually changes the crystal morphology. In the present study, the different cooling conditions were used to study the impact of solidification process parameters. For the case of simulation with small heat transfer coefficient, corresponding to the low cooling rate for practical solidification processes, the effects of the forced convection on crystal growth is more significant than that with larger cooling coefficient.