A novel Ti-Nb-xAg Superelastic Alloy with Enhanced Anti-bacterial and Superelastic Properties for Biomedical Implant

Combining novel superelastic Ti–40Nb alloys with the long-term, broad-spectrum antibacterial functionality of silver (Ag) represents a promising strategy to address stress shielding and bacterial infection in orthopedic implantations. In this study, Ti–40Nb–xAg (x = 1, 3, 5, and 7 wt.%) alloys were synthesized via mechanical milling followed by spark plasma sintering (SPS). The effects of varying Ag content on the microstructure, mechanical properties, superelastic behavior, electrochemical corrosion performance, antibacterial activity, and cytocompatibility were systematically investigated. XRD analysis revealed that the alloys consisted primarily of [Formula: see text]-Ti, [Formula: see text]-Ti, and trace [Formula: see text] phases. The Ti–40Nb–xAg alloys demonstrated high compressive strength (1431–1692 MPa), a low elastic modulus (46–52 GPa), and superior shape recovery rates ([Formula: see text]). Furthermore, increasing the Ag content markedly enhanced both corrosion resistance and antibacterial activity. Specifically, the highest antibacterial rates against Escherichia coli and Staphylococcus aureus reached 97.5% and 98.5%, respectively. In vitro evaluations further confirmed that the alloys exhibited no cytotoxicity toward mouse bone marrow mesenchymal stem cells (mBMSCs). Overall, the optimized Ti-40Nb-5Ag alloy exhibited an optimal balance of mechanical performance, antibacterial efficacy, and biocompatibility, underscoring its strong potential as an advanced candidate for orthopedic implant applications and providing a valid strategy for fabricating high-performance biomedical titanium alloys.