Abstract:

The phase transformation behavior and microstructural stability of P/M superalloy FGH95 in the long time stress ageing have been studied. It has been found that the hot-isostatically pressed FGH 95 alloy, which is in solution and ageing state and is subsequently subjected to long time stress ageing at 650℃ and lower temperatures consists of γ, γ',MC, M23C6 and M3B2 phases. A certain amount of secondary γ' coarsened, while some dissolved during the stress ageing. The γ' and minor phases contents showed a tendency to increase and grain boundary precipitation also increase as the stress ageing time increased. This alloy exhibits a relatively good structural stability.

Key words: hot-isostatical press （HIP）, phase transformation, stress ageing