Room and elevated temperature fatigue crack propagation behavior of Inconel 718 alloy fabricated by laser powder bed fusion

Abstract The fatigue crack propagation (FCP) behavior of Inconel 718 alloy manufactured by laser powder bed fusion (L-PBF) was studied at 25 and 650 °C, and compared to those of conventionally processed counterpart. The FCP rates of L-PBF Inconel 718 alloy were found to be significantly higher than those of conventionally processed counterpart at 25 °C in low and intermediate ΔK regimes. The FCP rates decreased in near-threshold ΔK regime at 650 °C, while the reversal occurred above ΔK of 7 MPa√m, as compared to those at 25 °C. The FCP behavior of L-PBF Inconel 718 alloy was discussed based on micrographic and fractographic analyses.