A novel Co-free high-entropy alloy with excellent antimicrobial and mechanical properties

Abstract

Microbiologically influenced corrosion and bacterial infection lead to serious losses to human production and life. Developing alloys with inherent antibacterial properties is a vital way to solve the above issues. However, the widely used Cu-containing stainless steels show insufficient antimicrobial properties and relatively low yield strengths, which further limit their application in extreme service environments. Based on the design concept of high-entropy alloys (HEAs), a novel low-cost Co-free CrFeNi_0.5Cu_0.3 HEA with an optimal combination of antibacterial and mechanical properties was designed and prepared. This alloy comprises triple-phase structures, including FeNi-rich face-centered cubic (FCC1), Cu-rich FCC2 and FeCr-rich body-centered cubic (BCC). The antibacterial rate of this HEA is up to 99.99% against Escherichia coli, which is far superior to that of classic 304 Cu-bearing stainless steel (304-Cu SS) and the most reported antibacterial alloys. In addition, the HEA exhibits excellent mechanical properties with a tensile strength of 1032 MPa and yield strength of 842 MPa, far surpassing the corresponding values of 304-Cu SS (i.e., 528 MPa and 210 MPa, respectively). These findings provide new insights for the development of low-cost and high-performance antibacterial alloys.

Graphical abstract