Effect of Thermomechanical Treatment on Mechanical Properties and Microstructure of Titanium Alloy Ti-6AL-4V ELI for Orthopedic Applications

Traffic accidents and osteoporosis significantly contribute to the incidence of fractures in Indonesia, increasing the need for orthopedic implant materials, such as titanium alloy Ti-6Al-4V ELI, which has good biocompatibility and availability in the market. However, its strength needs to be increased through thermomechanical treatment to maintain its durability. In this study, such treatment was applied with a combination of solution heat treatment at 950°C and a 1-hour holding time, followed by, subsequently, rapid cooling using water quenching, plastic deformation with deformation variations of 10%, 20%, and 30%, and aging treatment at a temperature of 550°C and holding time for 1.5 hours. The material surface microstructure was observed using an Olympus GX71 optical microscope; the chemical composition was measured using Electron dispersive X-ray, and; the hardness was measured using a Vickers microhardness tester. All data obtained were then analyzed to determine the effect of thermomechanical treatment on the increase and changes in the tested material’s hardness and microstructure, respectively. The results showed that thermomechanical treatment could increase the hardness of Ti-6Al-4V ELI, as expressed by the equation HVN = 135ε + 381.5, with a correlation coefficient of 0.991. Hence, it could be concluded that thermomechanical treatment can increase the hardness of Ti-6Al-4V ELI and, finally, change its microstructure, indicating an increase in the α phase. Therefore, Ti-6Al-4V ELI treated with thermomechanical treatment can be an alternate material in orthopedic implant applications.