Influence of heat treatment on microstructure of Ni₃Al based single crystal superalloy

The effect of heat treatment (solution and age treatment) on Ni₃Al based single crystal superalloy was investigated in this study. The solution temperatures of the experimental alloy were 1315-1335°C, 1320-1340°C and 1325-1345°C, and all the solution treatments could eliminate dendritic microsegregation in the occurrence of incipient melting. The primary age temperatures and times range was 1100-1130°C and 1-4 h, while the secondary age times were 16-40 h at 870°C. There was a comprehensive consideration of microstructure, actual working status of tube furnace and cost factor, and the optimum heat treatment was 1320-1340°C/16 h, air cooling (AC)+1120°C/3 h, AC+870°C/32 h, AC.