Effects of thermal exposure on high-cycle-fatigue behaviours in Ni-based superalloy GH4169 |
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| Authors: | R. Jiang D. W. Ji H. C. Shi X. T. Hu |
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| Affiliation: | 1. Key Laboratory of Aero-engine Thermal Environment and Structure, Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People’s Republic of China;2. College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, People’s Republic of China;3. College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, People’s Republic of China |
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| Abstract: | Effects of thermal exposure (TE) on high cycle fatigue (HCF) behaviours in Ni-based superalloy GH4169 have been investigated in this study. GH4169 specimens were thermally exposed at 650°C for 1, 2, 7, 14 and 21 days before fatigue test. These TEs produced eruptions, bulge-like features and pits at surface due to oxidation of carbides/nitrides. Fatigue life was not reduced evidently by TE as compared to the specimens in virgin conditions, indicating the insignificant influence of TE on HCF life. Fracture morphology analysis showed fatigue crack mainly initiated from oxides, crystallographic facets and subsurface inclusions. Although long TE is not necessarily related to crack initiation from oxides, crack initiation from oxides is generally associated with a shorter fatigue life. |
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| Keywords: | Ni-based superalloy thermal exposure oxidation high cycle fatigue fatigue crack initiation microstructural evolution fatigue behavior deformation mechanism |
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