Microscopic phase-field simulation for reageing of Ni-Al-Cr alloy

Based on the microscopic phase-field model, the reageing behavior of Ni-11at%Al-7at%Cr alloy from 873 K to 1023 K was simulated at atomic-scale, The order parameter profiles and volume fraction of the ordered phase was calculated according to the atomic morphology evolution, and the reageing process from 873 K to 1023 K was compared with ageing at 1023 K. The results show that the precipitated phase are all L1₂ phase under the two kinds of process, the precipitation mechanism of reageing is the mixture of non-classical nucleation and spinodal decomposition, and the precipitation mechanism of ageing is spinodal decomposition; the precipitated phase under reageing exhibits disperse grain with 45° angle arranged, and the shape of precipitated phase under ageing presents wide striation with 45° angle arranged, the incubation period of ageing is longer than that of reageing, the volume fractions of the ordered phase under these two kind of processes are equal while the equilibrium state reaches.