Very-High-Cycle Fatigue Behavior of Inconel 718 Alloy Fabricated by Selective Laser Melting at Elevated Temperature
Open Access
- 20 February 2021
- Vol. 14 (4), 1001
- https://doi.org/10.3390/ma14041001
Abstract
This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107–108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107–108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.Funding Information
- Tianjin Science and Technology Bureau (19YFFCYS00090)
This publication has 27 references indexed in Scilit:
- A review of mechanical properties of additively manufactured Inconel 718Additive Manufacturing, 2019
- Assessment of mechanical properties and fatigue performance of a selective laser melted nickel-base superalloy Inconel 718Materials Science and Engineering: A, 2019
- Effect of scanning strategy on mechanical properties of selective laser melted Inconel 718Materials Science and Engineering: A, 2019
- Fatigue life and mechanistic modeling of interior micro-defect induced cracking in high cycle and very high cycle regimesActa Materialia, 2018
- The influence of Laves phases on the high-cycle fatigue behavior of laser additive manufactured Inconel 718Materials Science and Engineering: A, 2017
- Microstructure and hardness studies of Inconel 718 manufactured by selective laser melting before and after solution heat treatmentMaterials Science and Engineering: A, 2017
- Microstructure, Fatigue Behavior, and Failure Mechanisms of Direct Laser-Deposited Inconel 718JOM, 2016
- Low cycle fatigue behavior of direct metal laser sintered Inconel alloy 718International Journal of Fatigue, 2016
- Microstructure and mechanical properties of selective laser melted Inconel 718 compared to forging and castingMaterials Letters, 2016
- Fatigue strength of Inconel 718 at elevated temperaturesFatigue & Fracture of Engineering Materials & Structures, 2000