The microstructure and fatigue performance of Inconel 718 produced by laser-based powder bed fusion and post heat treatment. (March 2022)

• Record Type: Journal Article
• Authors: Liu, S.Y.; Shao, S.; Guo, H.; Zong, R.; Qin, C.X.; Fang, X.Y.
• Is Part Of: International journal of fatigue. Volume 156(2022)
• Publication Date: 2022-03
• Subjects: Microstructure -- High cycle fatigue -- Inconel 718 -- Laser-based power bed fusion; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2021.106700
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: The fatigue strength increased 27% after heat treatment. The fatigue crack origins primarily involve the printing defects. The defect area is pretty larger in fracture surface than in bulk samples. The fatigue strength could be predicted using the defect size prior to fatigue test. Abstract: Microstructure, defects and their effects on the fatigue properties of Inconel 718 alloy after laser-based power bed fusion and subsequent heat treatment were extensively investigated. A large number of γ′ and γ″ phases were produced in the heat-treated samples while little changes in grain morphology and texture occurred. The hardness, tensile strength, and fatigue limit increased by 46%, 41%, and 27%, respectively, after heat treatment. The fatigue limit could be predicted using defects based on optical microscopy measurement of the bulk samples and examination of SEM fatigue crack origins via a combination of Murakami model and extreme value statistics.