A three dimensional modified cellular automaton model for the prediction of solidification microstructures

Abstract

A three dimensional modified cellular automaton model (3-D MCA) was developed in order to simulate the evolution of microstructures in solidification of alloys. Different from the classical cellular automata in which only the temperature field was calculated, this model included the solute redistribution both in liquid and solid during solidification. The relationship between the growth velocity of a dendrite tip and the local undercooling, which consists of thermal, constitutional and curvature undercooling terms, was calculated according to the KGT (Kurz-Giovanola-Trivedi) and LKT (Lipton-Kurz-Trivedi) models. The finite volume method, which was coupled with the cellular automaton model, was used to calculate the temperature and solute fields in the calculation domain. The present 3-D MCA model was applied to predict the microstructures, such as the free dendritic growth from an undercooled melt, the competitive dendritic growth in practical casting solidification. Some of the simulated results were compared with those obtained experimentally.