Solidification shrinkage and shrinkage-induced melt convection and their relation with solute segregation in binary alloys

Abstract

Shrinkage flow of melt in the mushy zone are closely related to solidification cracking. Here, the phase field (PF) and Lattice Boltzmann Method (LBM) used to predict the dendrite morphology, solute precipitation and diffusion with different solid and liquid densities. A novel species conservation equation considering density changes was constructed to model convective and diffusive of solutes. We demonstrated that solidification shrinkage and shrinkage-flow can strongly affect the dendritic morphology and solute segregation. When solid density is considered, the predicted outline of dendritic decrease significantly, while the solute diffusion layer and the solute concentration at the front of dendrite increase with solid density. For multi-order solidification, solidification shrinkage cause larger solute segregation in the liquid. Then studied direction solidification with shrinkage flow in crystal growth and observed the effect of continuous feeding of melt to the liquid channel. The solute concentration in the channel increases with the orientation angle and solid density. The results from this work have application prospects in the simulation of solidification cracking.