Dong Chengli1,2, Hong Jianfeng1,2, Sha Aixue1,2, Peng Zichao2, Wang Xuqing2, Li Xingwu1,2

Abstract:

In view of the lack of key issues on the service performance evaluation of the extruded and forged FGH95 alloy under the service conditions of the aero-engine powder disc components, the present study first designed a feature-base specimen based on the maximum principal strain gradient on the retaining groove of the powder disc component according to certain design criteria, and verified the design method. Then, the fatigue life method based on the Theory of Critical Distances (TCD) was employed to predict the service life. Finally, the fatigue life method and failure mechanisms were validated. The results show that the three - dimensional spatial domain automatic search method proposed in the present study can obtain the maximum principal strain gradient on the retaining groove. Compared with the Morrow - modified total strain life method commonly used in engineering, the TCD-base life method considering the strain gradient can more accurately predict the fatigue life of the retaining groove. The important reason why the notched standard round bar specimen cannot accurately predict the fatigue life of the retaining groove is reasonably explained. The differences in the fatigue failure mechanisms of the notched standard round bar specimen, retaining groove and its feature-base specimen are verified by fracture analysis techniques.