Thermo-mechanical fatigue behavior of nickel-base powder metallurgy superalloy FGH96 under tension-tension loading

Yuli GU,Yuhuai HE,Shiyu QU,Guodong ZHANG,Fei ZHENG and Chunhu TAO Beijing Institute of Aeronautical Materials,Beijing 100095,China

摘 要：Thermo-mechanical fatigue（TMF） behavior of FGH96,a nickel-base powder metallurgy superalloy,has been studied under tension-tension loading at the temperature range from 550 to 720 ℃.The results show that TMF fracture mode is intergranular for the in-phase（IP）,but transgranular cleavage-like for the out-of-phase（OP） samples.The total content of Al,Ti and Nb in the γ phases for the IP or OP samples and the partitioning ratio of γ /γ in these elements for the IP samples are relatively higher at the lower strain amplitude,which is consistent with the case of the γ size that is larger at the lower strain amplitude,the lattice parameter misfit is negative and the absolute value is lower at the lower strain amplitude that is correlative with the change of the γ morphology.The deformation at the lower strain amplitude is mainly dominated by the dislocation lines and dislocation pairs in the matrix channels,at the higher strain amplitude dominated by the large numbers of superlattice stacking faults within the γ phases.

关键词：