Study on the corrosion, tribocorrosion, biocompatibility, antibacterial performances of Ti6Al4V-Cu alloy produced by laser powder bed fusion

Abstract

Ti6Al4V alloys, widely used as dental and orthopedic implants, suffer from tribocorrosion by cyclic loads from patient activity, resulting in cell damage and implant failure. This work investigates the corrosion resistance, tribocorrosion, and antibacterial performance of Ti6Al4V-xCu (x = 0, 1, 3, and 5 wt%) alloys for potential use as metal implants. The alloys were fabricated using laser powder bed fusion (LPBF) and subsequently heat treated at 800 °C for 1 hour followed by 600 °C for 1 hour. The results revealed that the microstructure of Ti6Al4V-xCu alloys is composed of α and nano-Ti2Cu phases, where the volume fraction of Ti2Cu increases from 0.6 % (1 wt% Cu) to 5.8 % (5 wt% Cu). As a result, the tribocorrosion volume of Ti6Al4V-5Cu alloy is reduced by ∼37.5 % compared with Ti6Al4V, and its antibacterial rate is 91.4 %. The enhanced tribocorrosion is attributed to the formation of in-situ passivation film, the self-lubrication action of Cu, the gradient nano-grain strengthening of deformation driven and the precipitation strengthening of nano-Ti2Cu. Moreover, the enhanced antibacterial ability is attributed to the combined mechanisms from the electrostatic bonding of Cu ions and the contact-killing of Ti2Cu phase to bacteria. Therefore, the Ti6Al4V-5Cu alloy with α and nano-Ti2Cu phases can be used as a promising candidate for superior biomedical implants.