Nfluence of oxidation on the thermal properties of alloy TI 6AL 4V for applications in prosthesis - heat treatment of 5 hours at ambient air

Abstract

Titanium alloys are prominent among the materials for use in prostheses because they have high mechanical / weight resistance, good corrosion resistance and high biocompatibility. Among the titanium base alloys for biomedical applications, the main one is Ti-6Al-4V. However, recent research shows that the dissolution of Al and V may cause cytotoxic effects. To limit the dissolution of these elements was decided to form an oxide layer by thermal oxidation. This treatment also aimed to increase the surface roughness in order to improve bone-integration in case of implants. Therefore, this study aims at analyzing the influence of thermal oxidation on the surface properties of the Ti- 6Al-4V. Oxidation tests were carried out between 300 and 700 °C in air atmosphere for 5 hours. The oxides were evaluated by testing using X-ray diffraction, scanning electron microscopy, Vickers hardness, adhesion by Rockwell-C hardness test, surface roughness and corrosion-wear tests. It was observed that the surface roughness increases with oxidation temperature. On the other hand, the hardness and corrosion resistance-wear achieve the best results for the samples oxidized at 600 and 650 °C respectively. The adhesion tests have shown that the oxide film has good adhesion at 600 °C. Above this temperature the oxide film has low adhesion due to the presence of higher stresses in the film during formation.