Microstructure and Corrosion Resistance of Manganese‐Aluminum Bronze Alloy Fabricated by Laser‐Directed Energy Deposition

Manganese‐aluminum bronze (MAB) alloy was fabricated by laser‐directed energy deposition (L‐DED). The differences in microstructure and corrosion behavior between the as‐deposited alloy (L‐DED‐MAB) and the as‐cast alloy (Cast‐MAB) were investigated. The microstructure of Cast‐MAB consisted of an α phase matrix, a β solid solution phase, and multiple intermetallic κ phases (κ‐I, κ‐II, and κ‐IV). In contrast, the L‐DED‐MAB alloy exhibited a homogeneous microstructure with significantly refined equiaxed grains; the grain size was reduced by approximately 70% compared with that of the as‐cast alloy, and the precipitation of the κ‐I phase was suppressed. Electrochemical tests revealed that L‐DED‐MAB possessed superior corrosion resistance. After 7 days of immersion, it showed a lower corrosion current density and a higher polarization resistance, which was mainly attributed to the formation of a uniform and dense passive film on the surface. This work demonstrates the feasibility of fabricating MAB alloys by the L‐DED process and provides a promising route for manufacturing high‐performance marine components that combine strength and corrosion resistance.