Effect of heat treatment on microstructural evolution and corrosion behavior of wire-arc additive manufactured nickel aluminum bronze alloy
Ahmed Aliyu, D.P. Bishop, Ali Nasiri
Abstract
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.