Designing Nickel Aluminum Bronzes with enhanced properties via heated platform laser powder bed fusion

The demand for fabricating Nickel Aluminum Bronze (NAB) via laser powder bed fusion (LPBF) is increasing due to its expanding use in marine applications. Reliable LPBF-NAB components require optimised processing to prevent cracking while maintaining a balance of mechanical strength and corrosion resistance. In this study, LPBF was performed using a heated building platform at 550 °C to produce crack-free NAB components. Platform heating reduces thermal gradients, lowering cooling rates and enabling partial diffusion-driven transformations. This promotes the formation of α phases within the β/β′ matrix, along with Fe–Al and Ni-Al rich κ-phases. It also decreases internal stresses through dislocation annihilation and facilitates conversion of β/β′ phases into stable α+κ phases, reducing cracking and localised corrosion. The resulting microstructure, α+κ phases within a fine-grained β/β′ matrix, enhances mechanical performance through grain boundary and dislocation strengthening, as well as κ-phase reinforcement. The fabricated components exhibit yield strength approximately 60% higher than previously reported values, while ultimate tensile strength and elongation are comparable to cast, wrought, and heat-treated LPBF-NAB counterparts. Corrosion current density decreases by ∼33% relative to cast, annealed LPBF-NAB, and heat-treated or untreated cast and wrought NAB components, indicating improved corrosion resistance.