Numerical Simulation of Dendrite Growth during Solidification

Abstract

A comprehensive probabilistic model for simulating dendrite morphology and investigating dendritic growth kinetics during solidification has been developed, based on a modified Cellular Automaton (mCA) for microscopic modeling of nucleation, growth of crystals and solute diffusion. The mCA model numerically calculated solute redistribution both in the solid and liquid phases, the curvature of dendrite tips and the growth anisotropy. This modeling takes account of thermal, curvature and solute diffusion effects. Therefore, it can simulate microstructure formation both on the scale of the dendrite tip length. This model was then applied for simulating dendritic solidification of an Al-7%Si alloy. Both directional and equiaxed dendritic growth has been performed to investigate the growth anisotropy and cooling rate on dendrite morphology. Furthermore, the competitive growth and selection of dendritic crystals have also investigated.

A Model for Initial Spherical Growth during Equiaxed Solidification

“…Thus, the fundamentals of crystal growth kinetics attract numerous research interests [1][2][3][4][5][6][7][8][9] but the understanding of equiaxed crystal growth is inadequate because of the complexity of the process. Basically, the processing of crystal growth relies only on the undercooling, AT, in the liquid, which is given as AT = AT, + AT r + AT C + AT k (1) where AT, , AT r , AT C and AT k are the thermal, curvature, constitutional and kinetic undercooling, respectively.…”