Additive manufacturing of high-strength Inconel 718 alloy through the addition of Ti2AlC MAX particles

作者：Kong, Yu; Peng, Kaiyuan; Huang, Haihong^*

来源：JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 2023, 158: 180-193.

DOI：10.1016/j.jmst.2023.01.059

• Additive manufacturing
• Inconel 718
• Max phase
• Microstructure
• Mechanical properties

Decreasing the content of detrimental Laves phase in additively manufactured Inconel 718 alloy is highly essential. In the present study, we introduce a novel approach to effectively suppress the precipitation of Laves phase. By ex-situ incorporation of Ti2AlC MAX particles, Ti2AlC/Inconel 718 composites with Ti2AlC volume fractions of 5% and 10% are successfully fabricated using the directed energy deposition (DED) technique. In comparison to the Inconel 718 alloy, the 10 vol.% Ti2AlC/Inconel 718 composite exhibits 70.9% higher yield strength, 39.1% higher ultimate tensile strength, and 61.4% higher hardness. A detailed microstructure examination confirms that the detrimental Laves phase, which is abundantly present in the inter-dendritic region, is replaced by in-situ formed (Nb,Ti)(C,N) and gamma' particles with average diam-eters of 1.12 mu m and 10 nm, respectively. Through non-equilibrium solidification process simulation, the suppression of Laves phase, in-situ formation of multi-scale precipitates, and the microstructural evolu-tion due to Ti2AlC addition are illustrated at the mechanistic level. Conclusively, a theoretical model of Ti2AlC/Inconel 718 composite is developed to reveal its underlying strengthening mechanism. It is indi-cated that Ti2AlC/Inconel 718 composites possess the capability to be a next-generation high-end nickel-based alloy.