Optimization of mechanical and antibacterial properties of SLM–fabricated TC4–5Cu alloy by annealing heat treatment

Our previous researches indicated that additive manufactured TC4–5Cu alloy has limited ductility and antibacterial properties, which restrict its range of applications. In this research, comprehensive heat treatment studies were carried out on Ti6Al4V-5 wt%Cu alloy fabricated by Selective Laser Melting (SLM). Heating temperatures ranging from 730° to 930°C were used with different cooling rate under air and furnace conditions. It was showed that the annealing heat treatment could significantly influenced the microstructure, mechanical properties, and antibacterial properties of the SLM-fabricated TC4–5Cu alloy. Notably, the 780 air-cooled sample exhibited outstanding antibacterial rate which exceeded 99.9 %, along with good tensile strength and plasticity comparable to that of TC4 alloy. The morphology and distribution of the CuTi2 phase was proven to played a crucial role in determining the mechanical and antibacterial properties of the alloys. Furthermore, the antibacterial mechanism of the TC4–5Cu alloy was mainly contact sterilization, supplemented by release sterilization.