Investigation of microstructures and high-temperature tensile behavior of heat treated GTD222 nickel-based superalloy prepared by selective laser melting

Abstract

In this study, various heat treatment methods including direct aging and solution aging were performed on the selective laser melted (SLMed) GTD222 nickel-based superalloy, and the microstructures and high-temperature tensile behavior of the superalloys were systematically investigated. The results indicate that, in comparison to the as-deposited superalloy, both direct aging and solution aging lead to a significant enhancement in high-temperature strength and ductility. The directly aged superalloy exhibits a higher yield strength, while the solution-aged ones displays superior elongation. Specifically, at a tensile temperature of 760 °C, the superalloy subjected to a solution treatment at 1240 °C demonstrates the most favorable tensile properties, boasting a tensile strength of 835 MPa, an elongation rate of 6.5 %, and a reduction in area of 13 %. This study also provides a detailed discussion of the high temperature tensile behavior of the SLMed GTD222 superalloy after heat treatment.