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Effects of Hold Time on Fatigue Crack Growth Behavior in PBF-EB Inconel 718

Qiuyi Wang¹, Rong Yang¹, Bo Chen², Rui Bao^1,*

1 School of Aeronautic Science and Engineeing, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, China
2 Department of Mechanical Engineering, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom

* Corresponding Author: Rui Bao. Email:

The International Conference on Computational & Experimental Engineering and Sciences 2024, 29(1), 1-1. https://doi.org/10.32604/icces.2024.011878

Abstract

Effects of hold time on the fatigue crack growth behavior in electron-beam powder-bed-fusion (PBF-EB) Inconel 718 alloy at 650 ∘C have been investigated in this study, with focuses on the anisotropic fatigue cracking resistance and fracture mechanism. The V-type specimen (which loading parallel to the columnar grain boundaries) gives better dwell-fatigue cracking resistance to the H-type specimen (which loading perpendicular to the columnar grain boundaries) due to its large deflections (nearly 90 °) on the crack path. These deflections are related to the change of crack growth mechanism. In both V-type and H-type specimens, when the dwell-fatigue crack tip reaches high angle grain boundaries, the crack exhibits a intergranular propagation behaviour. Besides, discontinuous secondary crack which associated with high angle grain boundaries can be seen in the H-type specimen, indicating that the crack mechanism may be predominantly creep damage.

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Keywords

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