Hydrogen embrittlement behavior of Inconel 718 alloy prepared by selective laser melting
Post-heat treatment can effectively improve the strength plasticity matching of Inconel 718 alloy prepared by selective laser melting(SLM),but its hydrogen embrittlement(HE)fracture behavior is still unclear.For this purpose,the Inconel 718 alloy prepared by SLM was subjected to high-temperature solution+single-stage aging treatment,and its microstructure was analyzed using electron backscatter diffraction(EBSD)and backscatter electron microscopy(BSE)imaging under scanning electron microscopy.The hydrogen embrittlement sensitivity of the alloy was evaluated by tensile experiments before and after hydrogen pre-charging,and the fracture surface morphology and crack propagation path of the tensile samples were analyzed using EBSD and BSE.The results show that after heat treatment,the tensile strength of the Inconel 718 alloy prepared by SLM can reach 1341 MPa,and the elongation is 24.5％,but it also has high hydrogen embrittlement sensitivity.After 96 h of hydrogen charging,the strength and plastic loss of the alloy reach 18.5％and 52.3％,respectively.The stress concentration caused by the 8 phase and slip bands at the grain boundaries during the tensile process promotes the local enrichment of hydrogen at the grain boundaries,thereby inducing the initiation and propagation of intergranular hydrogen embrittlement cracks.
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