Achieving strength–ductility–corrosion resistance balance in Cu–Ni–Al alloy via heterogeneous grains and coherent nano-lamellar precipitation

Achieving the strength–ductility–corrosion resistance balance in Cu–Ni–Al alloys is significant for marine engineering. Here, the Cu alloy featuring ‘heterogeneous grain distribution and coherent nano-lamellar precipitation’ was fabricated, which exhibits a combination of ∼1 GPa yield strength (improved by ∼30% compared to commercial alloys) and 16% tensile ductility. This microstructural feature not only endows the ultrahigh strength, but also significantly enhances the work-hardening ability through strong interaction between multiple defects and the lamellae-like L12-γ′ phase. Furthermore, its good corrosion resistance is attributed to a uniform Volta potential distribution and the rapid formation of a more compact, chemically stable passive film.