Refine
Document Type
Keywords
- Biomedical applications (2)
- Nanobiomaterials (2)
- Sintering (2)
- Tribological behaviour (2)
- Biomatériaux, (1)
- Nanotribology (1)
- Ti-20Nb-13Zr (1)
- Ti-Mo alloy (1)
- Ti-Mo-Zr (1)
- Ti–Ni (1)
Institute
Aiming to develop alloys with better properties for orthopedic applications, the focus of the present research was to evaluate the effect of Mo at.% content on structural, mechanical, and tribological properties of hot isostatically pressed Ti-xMo (x = 4, 8, 12, 15, and 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. Wear tests were conducted under different applied loads of 2, 8, and 16 N. Experimental results indicated that the 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 decreased with increasing Mo content (at.%) reaching the lowest values of 27 and 26 nm in the case of Ti-15Mo and Ti-20Mo, respectively. On the other hand, the coefficient of friction and wear rates were found to be decreasing with increasing Mo content.
Ti–Ni powder compacts were prepared by mechanical alloying (MA), followed by hot isostatic pressing (HIP). Afterwards, the samples were sintered at different temperatures (950, 1050, 1150 and 1250 °C). Microhardness, density, crystallite size as well as microstrain of the sintered samples were measured and analyzed. Wear characteristics in phosphate-buffered saline (PBS) solution was tested under different applied loads of 2 N, 10 N, and 20 N, respectively. The results indicated that the crystallite size continuously decreases with increasing sintering temperature and reaches the lowest value of 31.3 nm at 1250 °C. The relative density of the sample sintered at 1250 °C is 98.0%. Moreover, the higher sintering temperatures lead to the higher relative density and the increase in hardness and young’s modulus of the sample. At the same time the friction coefficient and wear rate were lower for the samples sintered at 1250 °C. This improvement in friction and wear resistance is attributed to the grain size refinement. Ti–Ni sintered at 1250 °C showed good tribological performance under all test conditions.
β-type Ti–20Nb–13Zr alloys with low Young’s modulus were prepared at different sintering temperatures (950, 1050, 1150, and 1250 °C). The morphological and structural characteristics of as-prepared samples were investigated by several methods. Wear tests were conducted using a ball-on-plate type oscillating tribometer under different applied loads (2, 10, and 20 N). The morphological characterization indicated that the mean pore and crystallite size continuously decreased with increasing sintering temperature to reach lowest values of 40 nm and 38 nm at 1250 °C, respectively. The relative density of the 1250 °C sintered sample was as high as 98.7%. Moreover, the higher sintering temperature resulted in higher relative density and closed porosity of the sample. Both the friction coefficient and wear rate were lower in the sample sintered at 1250 °C as compared to other samples. This enhancement in tribological properties was attributed to a closed porosity.
Le milieu médical est un perpétuel demandeur de biomatériaux compatibles surtout en orthopédie. Effectivement le nombre important d’arthroplasties effectuées chaque année ne cesse d’augmenter dans le monde, non seulement du fait vieillissement de la population (à partir de 65 ans), mais aussi de demandes de patients plus jeunes entre 45 ans et 55 ans. Actuellement, les composés à base de titane Ti sont largement utilisés comme des biomatériaux pour leur biocompatibilité, leur résistance à la corrosion et leur faible module d’élasticité. Le molybdène et le zirconium sont parmi les meilleurs éléments alliés parce qu’ils sont non toxiques et non allergiques et offrent d’excellentes propriétés. De plus,Le Zr peut augmenter la trempabilité et la résistance à la corrosion de l'alliage . Mo est un élément fort stabilisant pour la phase des alliages de titane et les alliages à base de Ti-Mo présentent des propriétés mécaniques adéquates compatibilité et bonne cyto-compatibilité . Par conséquent, le système Ti-Mo-Zr, qui a montré une bonnes performances et de magnifiques perspectives dans l’application de biomatériaux, a été intensivementétudié [1,2,3]. Cependant, les alliages de Ti largement utilisés, tels que les interstitiels extra-low (ELI) Ti-6Al-4V (wt.% en poids ), Ti- 5Al-2,5 Fe et Ti-6Al-7Nb, ont le risque de libérer de l'aluminium toxique (Al) et les Ions de vanadium (V) in vivo, ce qui peut causer des problèmes de santé, comme la maladie d’Alzheimer et la neuropathie[4].La métallurgie des poudres (MP), y compris la méthode de mixture des composants en poudre, qui consiste à fritter titane en poudre ou ses mélanges avec d’autres composants en poudre, est un procédé économique à moindre cout. La nanotechnologie est intervenue dans la structuration des biomatériaux à l’échelle nanométrique (entre1nmet 100 nm) par soucis d’amélioration des propriétés mécanique surtout le module de Young.