Abstract
Nickel–aluminum bronze (NAB) alloys are extensively used in marine engineering owing to their excellent resistance to corrosion, erosion, and cavitation in seawater environments. However, conventionally cast NAB alloys often exhibit coarse and heterogeneous microstructures, phase-selective corrosion, and limited control over phase distribution, which restrict their long-term performance in demanding applications. Additive manufacturing (AM), particularly laser powder bed fusion (LPBF), offers a unique opportunity to tailor the complex multiphase structure of NAB alloys through precise control of process parameters. In this study, nickel–aluminum bronze alloy (NAB C95800 / CuAl9Ni5Fe4) was fabricated using LPBF, and the effects of processing parameters on microstructural evolution, phase transformation, and corrosion behavior were systematically investigated. The rapid and non-equilibrium thermal cycles inherent in LPBF significantly influenced solidification and subsequent phase transformations, resulting in distinct microstructural architectures comprising α, β′, and κ phases with varying morphology, size, and distribution. Systematic variation of LPBF parameters enabled controlled modification of cooling rates and thermal gradients, directly governing phase stability and transformation pathways. Moreover, electrochemical corrosion testing revealed a strong correlation between corrosion behavior and microstructural features dictated by process conditions.