Tailorable copper-bearing titanium alloys with remarkable strength and ductility fabricated by spark plasma sintering for biomedical applications

Titanium and Ti-based alloys are widely used metallic biomaterials, however, the surgical infections related to bacteria always occur on the implants. Developing the antibacterial titanium alloys has been studied as one of the most effective methods to lower the inflammatory response. The addition of Cu element to Ti matrix can produce strong antibacterial properties. Here, the antibacterial Ti-xCu alloys (x = 3, 5, and 7 wt%) were fabricated by powder metallurgy (PM) technique using spark plasma sintering (SPS) route. The effects of Cu addition, SPS temperature, and post-heat treatment on microstructure and tensile properties of Ti-Cu alloys were investigated. The strengthening and deformation mechanisms were also discussed. The microstructures of PM Ti-Cu alloy consisting of alpha-Ti and Ti2Cu phases are fine and homogenous as well as free of porosity. With the increasing Cu addition, the yield and tensile strengths of Ti-Cu alloys increase, but the elongation decreases. The precipitation of Ti2Cu phases contributes the most increments of yield strength, and can also act as the barriers to pile up the dislocations during the plastic deformation, improving the work hardening rate and tensile strength. PM Ti-Cu alloys possess a good tensile strength of 575-810 MPa, and an excellent elongation of 11%-29%. The optimized tensile properties of PM Ti-5Cu alloys are comparable and even superior to those of Ti and other Ti-based alloys produced by traditional methods. Further, insights for the design and processing of PM Ti-Cu alloys with ample shaping freedom fabricated by SPS method are generalized and discussed.