A Xanthium sibiricum biomimetic Fe‐based medium‐entropy alloy with significant antibacterial and mechanical behaviors

Abstract In recent years, various highly pathogenic viruses have spread worldwide, posing serious threats to human life and property, thus creating an urgent demand for antibacterial structural materials. In this study, we developed two types of antibacterial medium‐entropy alloys (MEAs): as‐cast (Fe 63.3 Mn 14 Si 9.1 Cr 9.8 C 3.8 ) 88‐ x Cu 12 Ag x ( x = 2, 4 at%) (which do not require antibacterial aging heat treatment) and heat‐treated (Fe 63.3 Mn 14 Si 9.1 Cr 9.8 C 3.8 ) 99.5‐ x Cu x Ag 0.5 ( x = 2, 4 at%) (abbreviated as Cu x Ag0.5 and Cu12Ag x ). Both MEAs exhibit in transformation‐induced plasticity (TRIP) and twinning‐induced plasticity effects, demonstrating outstanding mechanical properties. Compared to 304 stainless steels, these MEAs exhibit superior corrosion resistance, with the Cu2Ag0.5 alloy performing the best, exhibiting a corrosion current density of 1.022 A·cm −2 and a corrosion potential of −0.297 V SCE . The antibacterial rate of the MEAs reached 99.9% after 24 h of interaction with Escherichia coli and Staphylococcus aureus , with Cu12Ag2 achieving 99.9% antimicrobial activity within 6 h, indicating a shorter activation time for antibacterial activity. According to first‐principles calculations of state density, work function, and surface energy, Cu12Ag2 demonstrated the highest ion release capability, with a work function of 3.7 eV and surface energy of 1.9 J·m −2 . The electrostatic adsorption of the Xanthium sibiricum bionic structure, characterized by a nanoscale spherical phase within the antibacterial phase with a size less than 350 nm, promotes ion penetration into bacterial cells, enhancing the synergistic effects of ionic, electronic, and catalytic antibacterial mechanisms. This study provides a new approach for designing high‐performance alloys that integrate functional and structural properties, offering broad‐spectrum, efficient antibacterial applications under load‐bearing conditions.