Roles of defects in high cycle fatigue of a powder nickel base superalloyThursday (28.05.2020) 10:20 - 10:40
The high cycle fatigue behavior of a powder nickel base superalloy under different temperature and stress was studied. The results show that the internal defects in the Powder Superalloy play an important role in the process of high cycle fatigue. At room temperature, the fracture fatigue cracks all start from the surface of the sample, most of the fractures are point-shaped, single source characteristics, individual fractures have multiple fatigue sources, and each fatigue source is point source; the source area is small plane like cleavage characteristics; at high temperature, the fracture fatigue cracks all start from the inside of the sample, at the same temperature, the fractures under low stress conditions are mostly from internal defects The defects are all oxide inclusions of Al and Mg. Under the condition of high stress, the cracks all originate from the internal point, and there are no defects in the source area, which are characterized by small cleavage like plane.