Abstract
A Laser Powder Bed Fusion Inconel 718 produced with intentionally non-optimized parameters is investigated to understand the role of defects and microstructure on the high-cycle fatigue life. Samples from three built directions and three heat treatments were used for fatigue tests at room and 650°C under (Formula presented.). Printing orientation has a minor effect on fatigue life at both temperatures. Most samples failed from lack of fusion defects, carefully analyzed by scanning electron microscope (SEM) observations. Surface defect leads to transgranular fracture surface, while subsurface initiation leads to crystallographic fracture surface. (Formula presented.) curves related to hot isostatic pressure condition shown that defects have higher influence at (Formula presented.) than at 650°C. Kitagawa diagrams are plotted for both temperatures to quantify the influence of defect size on fatigue limit. Natural cracks are observed at the surface in order to discuss the relative part of initiation life in the whole fatigue life.
Original language | English |
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Pages (from-to) | 4678-4693 |
Number of pages | 16 |
Journal | Fatigue and Fracture of Engineering Materials and Structures |
Volume | 46 |
Issue number | 12 |
DOIs | |
Publication status | Published - Dec 2023 |
Keywords
- additive manufacturing
- heat treatment
- high cycle fatigue
- lack of fusion defect
- microstructure