Effect of Ti2Cu precipitation on antibacterial property of Ti-5Cu alloy.

To instill pure Ti with an antibacterial effect, Cu was added by metallurgical alloying to produce Ti-5 wt% Cu alloy (Ti-5Cu alloy). The precipitation of the likes of Ti2Cu in a Ti-Cu alloy is one of the factors that influences its antibacterial property. However, in the present study, Ti-5Cu alloy precipitates with different microstructures were obtained by applying heat treatment at different temperatures and for different durations. After the heat treatment, metallographic, microstructure, and element analyses were performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS). The antibacterial property of the Ti-5Cu alloy was assessed by the plated-count method using Escherichia coli (E. coli). The microstructure analysis revealed that the solution-treated alloy had no precipitation, while the aged alloy contained precipitations of intermetallic Ti2Cu compound. The aged alloy exhibited better antibacterial performance as the duration of the aging treatment increased. The optimal heat treatment for Ti-5Cu was found to be aging at 700 °C for 4 h, at which point the nucleation formation of the Ti2Cu particles would assume an acicular morphology. These acicular precipitates exhibit a high Cu content which, in turn, influences the antibacterial performance.