Last modified: 2018-08-01
Abstract
Orthopedic implants are being increasingly used to replace or repair damaged bone tissue [1]. Ti-alloys are commonly used as an ideal biomaterial in medical devices such as dental, and orthopedic applications due to their enhanced biocompatibility, high corrosion resistance, high strength-to-weight ratio, low density, and superior mechanical properties [2 - 4].
Aiming to develop alloys with good properties for orthopedic applications, the focus of the present research is to evaluate the effect of Mo at.% content on structural, mechanical and tribological properties of hot isostatically pressed β- type Ti-XMo (X = 0, 4, 12, 16, 20 at.%) alloys. The structural evolution, mechanical properties and tribological behavior of the nanostructured Ti-XMo alloys were evaluated using X-Ray diffraction, Scanning Electron microscope and ball on disk tribometer. The wear tests were carried out in accordance with the ASTMG 99, ASTM G 13395 and ISO 7148-1:2012, standards under different applied loads of 2, 8 and 16 N respectively.
Experimental results indicated that structural evolution and morphological changes of the milled alloys were sensitive to their molybdenum (Mo) content. The morphological characterization showed that the crystallite size and the particle size decrease with increasing Mo content (at. %) reaching the lowest values of 27 and 26 nm in the case of Ti-15Mo and Ti-20Mo, respectively. The coefficient of friction and wear rate were lower in the binary titanium alloys with 15 and 20 at. % Mo content. This improvement in wear and friction resistance is attributed to the closed porosity and grain refinement for binary Ti- alloys with 15 and 20 Mo.