Laser beam powder bed fusion nickel-based superalloys: microstructure, alloy tailoring and mechanical properties

Laser beam powder bed fusion (PBF-LB) nickel-based superalloys offer advantages in design flexibility, lightweight, integrated manufacturing, and low cost. However, PBF-LB technology poses persistent challenges for nickel-based superalloys regarding defect mitigation and performance enhancement. Though there are multiple approaches, including process parameter optimisation, heat treatment, ceramic second-phase particles modification, and microalloying have demonstrated efficacy, the difference of nickel-based superalloys and complex optimisation strategies limit their universality. Consequently, establishing microstructure-property correlations and formulating strategic guidance for alloy tailoring are imperative. This review systematically discusses the fabrication methods during PBF-LB, while also discussing the influence of various microstructures. Subsequently, the forming mechanisms and elimination methods of defects were analysed. Then we proposed three key alloy tailoring methods of γ/γ′/γ′′ tailoring, microalloying, and ceramic second-phase particles modification. Finally, the impact of fabrication and alloy tailoring on the mechanical properties of nickel-based superalloys was comprehensively evaluated. This review guides the development of PBF-LB nickel-based superalloys and offers some practical suggestions for alloy tailoring to suppress defects and improve performance.This review investigates the relationships between the fabrication process, microstructure, alloy tailoring, and mechanical properties of nickel-based superalloys in PBF-LB. Defects in nickel-based superalloys are categorised, and special emphasis is placed on the impact of alloy tailoring methods, including γ/γ′/γ′′ tailoring, microalloying, and ceramic second-phase particle modification, on the microstructure and mechanical properties. Finally, recommendations and outlooks are provided in this review.