Microscopic phase-field simulation of L12 and D022 phases during the early precipitation process of Ni-Cr-Al alloys

The influence of temperature on the precipitation mechanism and sequence of L12 and D022 phases during the early precipitation process of a Ni-15.5at%Cr-14at%Al alloy was simulated based on the microscopic phase-field model. In the range from 873 to 1373 K, the precipitation mechanism transformed from spinodal decomposition to non-classic nucleation and growth; the incubation period prolonged gradually with increasing temperature. The volume fraction of L12 phases increased and that of D022 phases decreased. D022 phases disappeared at 1373 K, and finally single-phase L12 phases were formed.