1High Temperature Materials Research Institute，CISRI，Beijing 100081，China；2GAONAAero Material
Co.，Ltd.，Beijing 100081，China；3AECC Commercial Aircraft Engine Co.，Ltd.，Shanghai 200241，China
Abstract：The evolution behavior of γ′ phases during long-term aging at 750-850 ℃ in an advanced Ni-based powder
metallurgy（PM）superalloy FGH4102 was investigated. The results show that the primary γ′ phase has good
stability during long-term aging. The tertiary γ′ phase mainly exists in 750 ℃ and early stage in 800 ℃. After the
precipitation reaches saturation，it basically conforms to Ostwald ripening theory with the extension of aging time.
Then it gradually dissolves in the later stage. During aging at 700 ℃ and 850 ℃，anti-coarsening caused by splitting
occurs in the secondary γ′ phase. Nevertheless the secondary γ′ phase grow continuously with time increasing
at 850 ℃. In the later aging stage at 800 ℃ and 850 ℃ ，the secondary γ′ phases transform into cubic and align
along the <100> direction. The influence of aging temperature and time on the hardness of the alloy is great. In the
later aging stage，the change of hardness value is mainly dependent on the change of size of the secondary γ′ phase.
2020, Vol. 30 
