Effect of heat treatment on microstructural evolution and corrosion behavior of wire-arc additive manufactured nickel aluminum bronze alloy

In the pursuit of enhancing the corrosion resistance of wire arc additive manufactured nickel aluminum bronze (WAAM-NAB) alloy, this study explores its microstructural evolution and corrosion behavior before and after heat-treatment. The findings unveil that annealing significantly improves the alloy’s microstructure by increasing homogeneity, grain size, and κ-phase distribution, while reducing residual stress and promoting low-energy Σ3–60°//111 boundaries. These microstructural improvements enhance the alloy’s corrosion resistance in a 3.5 wt% NaCl solution by decreasing susceptibility to localized and galvanic corrosion and promoting stable passive film formation. Consequently, the heat-treated NAB-alloy shows superior corrosion performance, offering greater durability over its as-printed state. • NAB alloy was developed using the wire arc additive manufacturing technique. • Heat-treated NAB alloy demonstrated an enhanced microstructure, promoting greater homogeneity. • Corrosion behavior of both the AP-NAB and HT-NAB alloys were evaluated in a 3.5 wt% NaCl solution. • Corrosion resistance of both the AP-NAB and HT-NAB alloys exhibited improvements over time. • HT-NAB alloy displayed superior corrosion performance over its as-printed state.