Experimental investigation and life prediction for the load spectrum with flight mission characteristics on a P/M superalloy

The service load on high temperature rotating components of aero-engines generally exhibits flight mission characteristics. The general shape of the load spectrum is that Type III/IV cyclic loading and creep loading are superimposed on Type I cyclic loading. Meanwhile, the sequence of the Type III/IV cyclic and creep loading varies with mission. This work performed load spectrum test with this characteristic on the Ni-based alloy FGH96. Then a life prediction method was developed based on the Chaboche fatigue damage accumulation model and a modified time fraction model. Creep followed by Fatigue (C-F) test was carried out to reveal the creep-fatigue interaction and calibrate parameters. The results show that most test results fall within the 2-fold deviation band. The sequence of creep-fatigue loading within the load spectrum exhibited a limited effect on life. Finally, simplified methods were developed to improve analysis efficiency, and cases where simplified methods could replace the proposed method were discussed.