Microstructure, mechanical properties, corrosion resistance and anti-bacterial behavior of novel Co-free high entropy alloys

Abstract

In this work, a series of Co-free CrFeNiCuSix (x = 0.2, 0.3) high entropy alloys (HEAs) were designed and fabricated by suction casting, and their microstructure, mechanical properties, corrosion resistance and anti-bacterial behaviors have been systematically investigated. It is found that, all these HEAs are composed of FCC phase and have dendrite structure, while the dendrite and inter-dendrite regions are Cu-deplete and Cu-rich, respectively. Moreover, the increase in Si leads to the strengthening of this series of HEAs but would reduce their plasticity. The corrosion resistance is closely correlated with the distribution of Cu in these HEAs. The anti-bacterial rate against E. coli. is ~97% when x = 0.2, while that is ~90% when x = 0.3, indicating high anti-bacterial properties of these HEAs. This work indicates that these designed Co-free HEAs could have excellent comprehensive properties combining high ultimate tensile strength and plasticity, as well as good corrosion resistance and anti-bacterial properties, which provides a novel route in designing high-performance and low-cost anti-bacterial HEAs.