Abstract: Equilibrium phase diagram of the nickel-based P/M superalloy FGH4096 was tested by JmatPro software, and the γ′ phase dissolution results at different solid solution temperatures were studied by using OM and SEM methods according to the γ′ phase equilibrium dissolution temperature. The results show that the γ′ phase in the FGH4096 alloy calculated by the thermodynamic software JmatPro is dissolved in a large amount between 930-1100 ℃, and the complete dissolution temperature is above 1100 ℃. From 1110 ℃ to 1130 ℃, the grain size increases from 16.1 μm to 18.2 μm, and the change is not obvious, but from 1130 ℃ to 1160 ℃, the grain size quickly increases from 18.2 μm to 28.6 μm. While the γ′ phase in the nickel-based P/M superalloy FGH4096 plays a strengthening role, it also hinders the growth of grains. As the solid solution temperature increases from 1110 ℃ to 1130 ℃, the content of the γ′ phase decreases. The pinning effect is reduced, resulting in grain growth. Above 1130 ℃, the γ′ phase is completely dissolved, the pinning effect of the γ′ phase disappears, and the grains grow rapidly. Finally, it is determined that the actual complete dissolution temperature of γ′ phase in the FGH4096 alloy is between 1130-1140 ℃.

Key words: FGH4096 alloy, γ′ phase complete solution temperature, microstructure, solid solution treatment