Design of a novel CoCrFeNiCu0.3 high entropy alloy with desirable mechanical, corrosion and anti-bacterial properties via adjusting Cu distribution

Cu-containing high-entropy alloys (HEAs) with good antibacterial properties have application potential in the field of marine engineering. However, Cu tends to segregate in HEAs, which deteriorates the mechanical properties and corrosion resistance. This work proposed a feasible strategy to eliminate Cu segregation in FCC-structured HEAs by ball milling and spark plasma sintering using HEA powders and Cu powders. It was found that, with the increase of sintering temperature, the Cu-rich phase gradually dissolved-into the CoCrFeNiCu0.3 HEA and finally disappeared. Meanwhile, the distribution of Cu elements in HEAs gradually became uniformed. CoCrFeNiCu0.3 HEA with uniform distribution of Cu was successfully fabricated by sintering at 1400 °C. The dissolution of Cu-rich phase synergistically improved the strength and plasticity of CoCrFeNiCu0.3 HEAs. Meanwhile, the galvanic corrosion caused by Cu-rich phases was effectively restrained by the uniform distribution of Cu. Furthermore, the sintered CoCrFeNiCu0.3 HEAs preserved good antibacterial properties with an antibacterial rate above 95% due to the combined action of toxic sterilization of Cu ions and contact sterilization of Cu atoms. The CoCrFeNiCu0.3 HEAs with uniform distribution of Cu not only displayed good mechanical properties and corrosion resistance, but also exhibited outstanding antibacterial properties. This work provided a design concept for the development of marine structural materials.