Microstructure, corrosion and anti-bacterial investigation of novel Ti-xNb-yCu alloy for biomedical implant application

Novel Ti-xNb-yCu alloys containing various Cu and Nb concentrations have been developed through heat treatment and rapid quenching. The effects of Cu and Nb content on microstructure, corrosion properties and bacterial inhibitory ability of the novel alloys have been systematically investigated with various characterisation methods. Results revealed that Ti3Cu alloy showed a typical eutectoid structure (α-Ti and Ti2Cu), Ti10Nb3Cu alloy exhibited three-phase coexistence microstructure (α+β+Ti2Cu), Ti30Nb alloy comprised of α+β phases, and Ti30Nb5Cu and Ti30Nb3Cu alloys comprised of single β phase. The corrosion behaviour of novel Ti-xNb-yCu alloys were studied in details using electrochemical measurements and immersion testing. It has been found that corrosion resistance of novel Ti-xNb-yCu alloys was improved with increasing Nb content, while the addition of Cu exhibited opposite trend on corrosion resistance. Higher Cu content (5%) in Ti30Nb alloy decreased its corrosion resistance while lower Cu content (3%) improved its corrosion resistance, probably due to the single-phase transition and less Cu-containing precipitates on the grain boundary of Ti30Nb3Cu. Besides, Cu-containing Ti alloys exhibited significantly better bacterial inhibitory properties. This study suggests that, Ti30Nb3Cu alloy with high corrosion resistance and excellent bacterial inhibitory property is promising for biomedical implant applications.