Research on heat treatment of nickel–based superalloys by laser powder bed fusion: A review

Nickel–based superalloys are essential for high–temperature applications such as aerospace engines and gas turbines due to their superior mechanical properties and stability at elevated temperature. Laser powder bed fusion (LPBF) technology is widely used in nickel–based superalloys because it enables the production of complex geometries and intricate designs with reduced material waste and rapid prototyping capabilities. However, the localized heating and cooling inherent in LPBF lead to residual stresses, pore defects, cracks and suboptimal microstructure, necessitating effective heat treatment to enhance the mechanical properties of the alloy. This review comprehensively summarizes various heat treatment methods for LPBF nickel–based superalloys, including solution treatment, conventional treatment (for example, solution + aging treatment), novel treatment (such as direct aging treatment and multiple heat treatment), hot isostatic pressing (HIP) and HIP + conventional heat treatment. We explore both the role of these heat treatments and their impact on microstructure and mechanical properties at different temperatures. In addition, the changes in tensile, fatigue and creep properties of LPBF nickel–based superalloy after heat treatment at different working temperatures were further investigated. The review highlights critical insights into optimizing heat treatment processes to address the unique challenges of LPBF fabrication, which are crucial for advancing research and improving the performance and reliability of LPBF nickel–based superalloys in high–temperature environments. •The heat treatment regimes of LPBF nickel-based superalloys are studied in detail.•Novel heat treatment (direct aging and multiple heat treatment) regimes for LPBF nickel-based superalloys are explored.•The mechanical properties of LPBF nickel-based superalloys at high-temperature environments are summarized in detail.