A critical review on the microstructure and mechanical properties correlation of additively manufactured nickel-based superalloys

Inconel group of alloys, particularly IN 625 and IN 718 are the most widely recognized commercially available Ni-based superalloys employed for high temperature applications. These superalloys are known to retain their extraordinarily high strength at elevated temperatures either by solid solution or precipitation strengthening mechanisms. Consequently, they find crucial applications in the field of aerospace, automobile, and energy industries involving higher temperatures. Recently, attempts are being made to fabricate and repair the complicated superalloy components using metal additive manufacturing techniques. The ability of the additive manufacturing process to produce intricate geometry parts with greater dimensional accuracy as compared to various conventional techniques appear to be beneficial and cost-effective. However, this unique manufacturing method influences the microstructural evolution and thereby affects the performance of the IN 625 and IN 718 alloys significantly. Considering various research efforts in this direction, this article pursues a thorough review and presents a wide overview of the microstructure and mechanical properties correlation for these two additively manufactured Ni-based superalloys.