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 degrees 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 degrees C in low and intermediate Delta K regimes. The FCP rates decreased in near-threshold Delta K regime at 650 degrees C, while the reversal occurred above Delta K of 7 MPa root m, as compared to those at 25 degrees C. The FCP behavior of L-PBF Inconel 718 alloy was discussed based on micrographic and fractographic analyses.