Effect of alloying elements on the microstructure, coefficient of friction, in-vitro corrosion and antibacterial nature of selected Ti-Nb alloys

Abstract

Ti-Nb alloys having compositions Ti-24Nb-4Zr-8Sn, Ti-29Nb-13Ta-7Zr and Ti-35Nb-4Sn were synthesized by vacuum arc melting followed by ageing at 1273 K for 6 h in Ar atmosphere. The alloys were characterized by field emmision scanning electron microscopy (FESEM), transmission electron microscopy (TEM), micro X-ray diffraction, friction coefficient and nanohardness tests. In-vitro corrosion of the alloys were studied by potentiodynamic polarisation in body simulated fluid at 37 ○C. The alloy surfaces were exposed to staphylococcus aureus bacteria under controlled environment and the retention of the bacteria was examined by confocal laser scanning microscopy. The alloys had different ratios of α, β phases, different nature of inclusion, and dislocation pile-up resulting in high hardness. Alloys also had good resistance to in-vitro corrosion, low coefficient of friction and were resistant to bacterial growth as compared to commercially pure (CP) Ti. The coefficient of friction was lowest for Ti-24Nb-4Zr-8Sn and it increased with increasing Nb content. The resistance to bacterial growth on the surface increased with increasing volume fraction of β phase in the alloy.