Phase-field research of microstructure evolution for directionally solidified peritectic transition I. Extension of trijunction

A phase-field model was built by optimizing characteristic parameters in the convectional phase-field model for peritectic transition, which is suitable to simulate microstructure evolution for peritectic transition of specific alloys. The growth of peritectic phase along the primary phase surface was simulated using this model for directionally solidified Ti-Al alloy at a high value of G/v_p. The simulating results show that the difference of extending character of trijunction will cause two typical microstructures of discrete band and island band. Furthermore, the width of computational domain, the nucleation undercooling of peritectic phase and initial composition affect the extension of trijunction of directionally solidified peritectic alloy directly, and also the final microstructure.