Exceptional strength and antibacterial durability in hierarchically structured Cu-bearing 316L stainless steel through additive manufacturing

Abstract

As crucial materials within the biomedical domain, antibacterial stainless steels have garnered widespread utilization across various sectors. However, both the mechanical properties and antibacterial efficacy remain suboptimal in antibacterial stainless steels processed with traditional methods, including casting, forging, rolling, and multiple heat treatments. This inherent limitation significantly constrains the range of potential applications for these materials. Here, we report on a novel in-situ alloying strategy to fabricate hierarchically structured Cu-bearing 316L steels using additive manufacturing . Our approach results in an augmented yield strength exceeding 560 MPa, with the ultimate tensile strength near 600 MPa while preserving commendable ductility. Moreover, these high-strength Cu-bearing 316L stainless steels exhibit excellent antibacterial ability against both Escherichia coli and Staphylococcus aureus , with antibacterial rates reaching an impressive 100 %. The extraordinary strength enhancement in additively manufactured Cu-bearing 316L stainless steels originates from the synergistic interplay of multiple strengthening mechanisms due to hierarchical microstructure, including fine gains, cellular structure, deformed twins, stacking faults, and microbands . Simultaneously, the exceptional antibacterial ability could be traced to the heterogeneous distribution of Cu, printing defects and high-density grain boundaries in additively manufactured Cu-bearing 316L stainless steels, promoting the substantial release of Cu ions . The integration of additive manufacturing processes into the production of Cu-bearing stainless steels holds excellent promise, enabling the simultaneous attainment of high strength and outstanding antibacterial efficiency for a diverse range of applications.

Topics & Concepts