Tribological behaviour of Ti-based alloys in simulated body fluid solution at fretting contacts

Friction and wear play an important role in determining the performance of biomaterials. To this end, the present research is carried out to understand the tribological behavior of some important biometallic alloys, CP titanium, Ti–6Al–4V, Ti–5Al–2.5Fe, Ti–13Nb–13Zr, and Co–28Cr–6Mo under fretting contacts. The fretting experiments were carried out on candidate biometallic alloys against bearing steel at 10 N normal load for 10,000 cycles with relative displacement stroke between the flat and ball set to 80 μm and the frequency at 10 Hz on a fretting (low amplitude reciprocatory tangential sliding) wear tester. The tests were performed in Hank’s balanced salt solution to assess the performance of the materials in simulated body fluid (physiological) solution. The results revealed the lowest coefficient of friction (COF) of 0.3 for Ti–5Al–2.5Fe/steel couple while for other Ti-based alloys COF was in the range of 0.46–0.50. Tribomechanical wear, as evident from the observation of abrasion and cracking, is the predominant wear mechanism.