Numerical Simulation of Directional Solidification Microstructure of Ti-45Al Alloy Based on CA Method

The numerical model of microstructure evolution during directional solidification process of Ti-45Al(at.%) alloy was established based on CA method,which takes into account the binary alloy peritectic reaction process and simulated the directional solidification process with indium-gallium alloy liquid metal cooling.Simulation results show that the solidified microstructure can be divided into three regions consisting of primary equiaxed grain,stable columnar grain growth region and the transition region.The primary dendrites arm spacing of the columnar grains decreases with the increasing of the withdrawing rate.At the withdrawing rate of 0.1 mm/min,the simulation region was dominated by primary β phase,and in the solute-rich interspace between β dendrites a small number of peritectic α phase can be found,which matched the published experimental results very well.