Microstructure evolution during directional solidification of 2009Al/SiCp at different pulling velocities: Modeling and Experiment

The cellular automaton-lattice Boltzmann method-immersed moving boundary coupled model is established to study the microstructure evolution during the solidification process of 2009Al/SiCp. After several model benchmarks, the natural convection of liquid phase and its effect on particle settlement under different pulling velocities were studied firstly. The results showed that at higher pulling velocity, the particle decelerates downward before contacting with dendrite front due to intensified natural convection. At lower pulling velocity, the particle decelerates gradually until a change in direction and upward movement. As the particle approach the tip of the dendrite, the particle experiences a brief upward movement before contacting the dendritic front. Then the convection induced by particles has an impact on the distribution of solutes in the liquid phase. It has been observed that at lower pulling velocity, there is a significant difference in solute distribution at the solidification front. The primary reason for this phenomenon is the higher solute concentration near the solidification front at lower pulling velocity, rather than the higher liquid phase flowing rate. Finally, our model investigated the microstructure evolution process during the directional solidification process of 2009Al/SiCp at different pulling velocities. The results indicate a good agreement between the simulation results and experiment observations.