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 pre-cipitation 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 in-cubation 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.