Abstract:
The thermal stability of the selective laser melted nickel-based superalloys with the complex non-equilibrium solidified microstructure is different from that of the traditional cast and forged counterparts, and the traditional standard heat treatment process cannot obtain the stable structure and excellent properties accordingly. Therefore, it is imperative to clarify the inherent relationship between the metastable precipitate characteristics in non-equilibrium thermal cycles during the additive manufacturing and the heat treatment processes, such as grain growth, second-phase precipitation, and dislocation evolution during the thermal treatment. The γ″ strengthening nickel-based high-temperature alloys (IN718 alloy) were focused in this paper, which were widely used in the fields of aviation engines and gas turbines, the research progress on the microstructure characteristics after laser selective melting forming was discussed, and the microstructure evolution and variation laws of the mechanical properties after heat treatment were reviewed to explore the methods for regulating the microstructure and improving the mechanical properties of high-temperature alloys under the rapid solidification, and to further expand the application of laser additive manufacturing technology in hot-end structural materials, such as aviation engines and gas turbines.