Wire-arc directed energy depositing high-ductility Cu-10Fe immiscible alloy with a hierarchical microstructure

In this work, a thin-wall Cu-10Fe (10 wt%) immiscible alloy component is fabricated by wire-arc directed energy deposition (WA-DED), leveraging the high energy absorption of the electric arc for copper alloys and its high deposition rate. Results show that Liquid-Liquid Phase Separation (LLPS) occurs upon solidification during WA-DED, and a hierarchical microstructure is formed, including micro-sized and nano-sized Fe particles, nano-sized Cu particles, as well as Fe dendrites embedded in the Cu matrix. A slight mechanical property anisotropy is found via tensile testing, and the horizontal specimen has superior strength and ductility. The decent ductility, 37.1 ± 0.9 % in elongation, is achieved with a ductile dimple fracture mode. It is associated with the relatively fine grains, the hierarchical microstructure and the formation of twins. Our pioneering investigation on the microstructure and mechanical property of Cu-10Fe alloy via WA-DED provides an applicable pathway for the efficient fabrication of high-performance Cu-based immiscible alloys.