High-Temperature Low-Cycle Fatigue Properties of GH4169 Ni-based Superalloy

The total strain controlled high-temperature low-cycle fatigue experiments were conducted on the domestic GH4169 Ni-based superalloy. The fatigue properties of the alloy were studied and the fracture morphology was analyzed. The results show that the tested alloy had a superior low-cycle fatigue performance at elevated temperature, which was similar to that of imported Inconel 718 Ni-based alloy, but lower than the fatigue life of the Inconel 718 alloy at a relatively low total strain range. The cyclic stress softening behavior of the alloy was presented at different total strain ranges. The fatigue fractures of the alloy specimens showed a character of multi-crack sources and the crack source amounts decreased with the decrease of the total strain range and the prolonging of the fatigue life. The fatigue cracks all initiated at the specimen surface, and when propagated in an intergranular mode to a certain radial depth, showed a transgranular propagation characteristic.