Phase-field simulation of microstructure evolution during the initial stage of rapid solidification of alloys

Abstract

Microstructure evolution during the rapid solidification of Fe-C alloys is simulated using the phase-field model for binary alloys with thin interface limit parameters. The heat transfer equation is solved simultaneously to study the heat flow and the effect of latent heat generation on the microstructure. The calculations have been carried out using a double grid method and parallel computing technique. The competitive growth of growing cells was reproduced, and the cellular/dendritic transition was also observed. Since there is a negative thermal gradient in front of the leading tip, growth can be regarded as unidirectional free dendrite growth. The microstructure changes depending on the preferred growth orientation and the secondary arms start developing only on one side with the increase of the tilted angle. With the two-dimensional heat diffusion effect, negative thermal gradient appears on both the solid and liquid side of the leading tip.