Strontium oxide-reinforced Ti-6Cu alloys fabricated by mechanical alloying and spark plasma sintering: Enhancing antibacterial activity and bioactivity for biomedical implant

Titanium-based implants face two interconnected challenges: bacterial infection and mechanical mismatch due to high Young's modulus. This study develops innovative Ti-6Cu-xSrO composites (x = 0, 2, 4 wt%) via mechanical alloying and spark plasma sintering (1000 °C, 30 MPa). Microstructural analysis reveals uniform Cu precipitation within the Ti matrix, while SrO forms submicron agglomerates (∼900 nm) that influence load transfer and stiffening. The Ti-6Cu-2SrO composite achieves an optimal multifunctional balance: a 40% increase in osteoblast viability compared to Ti-6Cu (p < 0.01), moderate antibacterial activity (33% reduction in S. aureus viability over 24 h), and a Young's modulus close to other Ti implants. Increasing SrO to 4 wt% reduces antibacterial efficacy but maintains high cytocompatibility. Mechanically, SrO addition improves tribological performance, reducing wear rate by nearly one order of magnitude and increasing hardness from 509 to 551 HV. This design leverages Cu as an antibacterial agent and SrO as a bioactive osteogenic promoter, offering a significant advance in load-bearing implant materials.