Microstructure, mechanical properties and dry wear resistance of β-type Ti–15Mo–xNb alloys for biomedical applications

In order to study the effect of element Nb on the microstructure and properties of the biomedical β-type Ti-Mo based alloys, Ti-15Mo-xNb (x=5, 10, 15 and 20 in %) alloys were investigated. The dry wear resistance of β-type Ti-15Mo-xNb alloys against Gr15 ball was investigated on CJS111A ball-disk wear instrument. Experimental results indicate that crystal structure and morphology of the Ti-15Mo-xNb alloys are sensitive to their Nb contents. Ti-15Mo-xNb alloys match those for β phase peaks and no any phases are found. The Vickers hardness values of all the Ti-15Mo-xNb alloys are higher than HV200. The compression yield strength of the Ti-15Mo-5Nb alloy is the lowest and that of the Ti-15Mo-10Nb alloy is the highest. For all the Ti-15Mo-xNb alloys, the friction coefficient is not constant but takes a higher value. In dry condition, SEM study reveals deep parallel scars on the wear surfaces of all the Ti-15Mo-xNb alloys under different loads. The friction coefficient of the Ti-15Mo-5Nb alloy under 1 N is the lowest. The wear principal mechanism for Ti-15Mo-xNb alloys is adhesive wear.