Effect of low dissolved oxygen concentration on structure of regenerated passive film of Ti-6Al-4V alloy under continuous wear

Abstract

Abstract Tribocorrosion is one of the most common forms of failure of biomedical titanium alloys. As the passive film of titanium alloy is highly dependent on oxygen conditions, the passivation behavior and the microstructure of the passive film of Ti-6Al-4V under tribocorrosion in 1 M HCl with a low dissolved oxygen concentration (DOC) were studied by means of electron probe microanalysis (EPMA), Ar-ion etched X-ray photoelectron spectroscopy (XPS), focused ion beam (FIB) milling and HRTEM. The results showed that the protective ability of the regenerated passive film decreased sharply under low DOC. Structural characterization indicated that Ti atoms occupied more metal lattice points in the regenerated passive film and that the high dislocation density in the deformed layer caused by wear facilitated the diffusion of Al and V. Finally, the first-principles calculation showed that Al had the minimum vacancy formation energy.