New Insights on the Tribological Characteristics of Biomedical Ti–Mo Alloys Influenced by Microalloying Addition in Simulated Bodily Fluids

Titanium–molybdenum-based alloys are widely used as an orthodontic arch wire for performing an orthodontic mechanotherapy. However, the poor tribological behaviour of titanium-based alloys, in terms of high and unstable friction, severe adhesive wear; low resistance to abrasion has become a major setback. Herein, Ti₉₄Mo₆Xn(x = Nb, Ta, Zr and Sn) alloys were fabricated by arc melting and the effect of Nb, Ta, Zr and Sn minor-additions on tribological properties of βtype biomedical Ti-alloys in simulated body fluid (Ringer’s SBF solution) was studied. Additionally, the post-test characteristics, and morphology were studied by XRD, pin-on-disk tester, nano-indentation, 3D confocal microscope and scanning electron microscope (SEM). Results showed that anti-friction resistance rate and the extent of anti-wear resistance improved by up to 40% and 43% with Sn and Nb minor addition, respectively. It was exciting that these functionalised Ti–Mo-based alloys had higher friction and wear resistance than the commonly used Ti–6Al–4 V alloys, which can be beneficial for many biomedical applications.