Synergistic performance enhancement of additively manufactured copper-nickel dissimilar alloy components via a novel quasi in situ cryogenic treatment

Abstract Additively manufactured copper-nickel dissimilar alloy components hold significant promise owing to their multifunctional properties, but their interface layer defects and difficult-to-coordinate heat treatment processes hinder their widespread adoption. This study employs wire-arc directed energy deposition (DED) combined with a novel quasi in situ cryogenic treatment to address these challenges. By integrating a quasi in situ ultra-low temperature treatment on the first deposited and heat-treated Inconel 718 alloy during the subsequent deposition of the CuAl10 alloy, the ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) of the dissimilar alloy component increased by 47.7%, 25.3%, and 44.4%, respectively, compared with the counterpart fabricated with natural cooling. The cryogenic treatment further refined the microstructure of the interface layer by suppressing elemental diffusion and precipitate formation. Rapid cooling rates inhibit solidification cracking in the element diffusion interlayer, substantially enhancing the transverse tensile properties of the interface layer, with UTS, YS, and EL reaching 550.9 MPa, 467.8 MPa, and 4.2%, respectively. These results provide critical insights for strengthening interface layers and optimizing heat treatment strategies in additively manufactured dissimilar alloy systems.