Phase-field research of microstructure evolution for directionally solidified peritectic transition II. Simulation of nucleation-controlled microstructure

The microstructure evolution of both phases is simulated by the phase-field model of peritectic transition for directionally solidified Ti-Al alloy at a high value of G/v_P when the continuous nucleation occurred to a sample with a small diameter and the multiple nucleation occurred to a sample with a big diameter. The simulated results show that for the small sample decreasing sample size or nucleation undercooling of peritectic phase tended to form island band structure. But to the big sample, the differences of the volume fraction of peritectic phase and the nucleation rate cause to form the discrete band, island band and coupled-growth structures.