Advances in laser powder bed fusion of ceramic-reinforced superalloys: Processing, microstructure, properties, and perspectives

Superalloys are extensively utilized in the aerospace and energy industries due to their outstanding high-temperature strength, thermal stability, and corrosion resistance. However, the rapidly growing demands for higher thrust-to-weight ratios and elevated turbine inlet temperatures in advanced engines have posed significant challenges to current hot-section component materials. Ceramics, with their inherent high hardness and melting points, are promising reinforcement candidates. Incorporating ceramics into superalloys enables the design of composites that overcomes the intrinsic limitations of conventional alloys. The newly-developed laser powder bed fusion (LPBF) technique provides great potential for fabricating such composites with tailored structures and properties. However, porosity and cracking frequently arise during LPBF due to complex multi-field interactions, thus degrading their service performance. This review systematically summarized advances in LPBF-fabricated ceramic-reinforced superalloys. The key coupling relationships between ceramic particle characteristics, LPBF process parameters, and high-temperature service performance are systematically clarified. The metallurgical process, microstructure evolution, and precipitation behavior of superalloy composites are comprehensively scrutinized. The initiation and propagation mechanisms of metallurgical defects in these composites are explicitly analyzed and elucidated. Furthermore, the mechanical properties of the composite materials and their underlying strengthening mechanisms are thoroughly addressed. Finally, the bottleneck problems associated with ceramic-reinforced superalloy composites fabricated by LPBF are synthesized, and future perspectives are proposed.