Mechanical performance and corrosion behavior of Cu–7Al–2Ni–1Fe–1Mn alloy produced via laser and arc hybrid additive manufacturing

Nickel–aluminum bronze (NAB) alloy is an important engineering alloy extensively applied in shipbuilding and offshore environments. This research reports the first successful fabrication of thin-walled NAB alloy structures (Cu–7Al–2Ni–1Fe–1Mn) via laser and arc hybrid additive manufacturing (LHAM). A systematic comparative analysis was conducted on the microstructural features, mechanical performance, and corrosion behavior of specimens in both the as-deposited and heat-treated conditions. Compared with conventional wire arc additive manufacturing (WAAM), LHAM increased the molten pool thermal gradient, leading to improved deposition efficiency and dimensional accuracy. As a result of the combined action of two independent heat inputs, significant microstructural refinement was achieved. In the as-deposited condition, the material exhibited a single α-phase structure. Following heat treatment, finely and homogeneously distributed κ phases were precipitated, together with a pronounced increase in dislocation density. Consequently, the ultimate tensile strength (UTS) rose from 360.5 MPa in the as-deposited condition to 394 MPa following heat treatment, while an elongation exceeding 40% was maintained, indicating excellent plasticity. Moreover, uniformly dispersed fine κ phases significantly suppressed corrosion progression, thereby enhancing the corrosion performance of the NAB alloy. These results provide important references for alloy composition design and optimization of additive manufacturing process routes for NAB alloys.