Sliding friction and wear performance of the nano-bioceramic α -Al 2 O 3 prepared by high energy milling

The structural evolution and morphological changes of the nanostructured α-Al2O3 powder using different milling times (1, 8, 16 and 24 h) were studied. It is observed that the crystallite size of the particles reduced to 2 nm after milling for 24 h. Morphological studies of powder particles indicated that the powder particle size continuously decreases with increasing milling time. The sliding wear rate and wear coefficient of friction were lower in the nanocrystalline samples milled at 24 h at same applied load (3, 6 or 10 N). The improved friction and wear resistance is attributed to the finer microstructure of the sample milled for 24 h

Friction and Wear Performance of Biomaterials Alloy AISI 316L and Ti-6Al-7Nb

We became interested in this work to study the tribological behavior of two total hip replacements steel AISI 316L and titanium alloy Ti-6Al-7Nb tests performed in this work are essays with reciprocating movement. The tribological properties of wear by sliding (reciprocating) for the different samples were evaluated in the air on a tribometer with a tribotester software software following standards: ISO 7148, ASTM G99-95a, ASTM G 133-95, with a relative humidity of 33-38% at a temperature 24 to 27°C and a non-lubricated state. The ball 100C6 steel of 10 mm diameter, 835 HV hardness and Young’s modulus 310 GPa was chosen as the antagonist to prevent further chemical reactions. Three different speeds (1, 6 and 15 mms-1) and four normal forces (2, 4, 6 and 10 N) were applied, which allowed us to test twelve different conditions. The values of the friction coefficient obtained in this work are confirmed by the bibliographical results and meet the standards imposed by biomedical particularly at the joint surface state of hip prostheses

Caracterisation des proprietes mecaniques par nanoindentation d’un revêtement de zinc pour differentes epaisseurs de tôles galvanisees

La nano-indentation permet de connaître les propriétés mécaniques des surfaces ou des couches minces, en particulier leur dureté et leur module d'élasticité réduit. Ce travail porte sur la détermination des propriétés mécaniques d’un revêtement de Fer-zinc formé sur un substrat en acier de construction laminé à froid avec différentes épaisseurs de tôles. Ce revêtement, typiquement d’une épaisseur de l’ordre 10-20 μm résultant d’un traitement de galvanisation, est constitué des phases êta, dzêta, delta et gamma (interface substrat/revêtement). Les échantillons sont issus de tôles galvanisées dans les conditions d’Arcelor Mittal Annaba. Les essais de nano indentation ont été menés en mode continu à l’aide d’un appareil Nano-Indenter XP ©. L’avantage de ce mode (CSM), est de rendre possible la mesure du contact indenteur/échantillon et donc la dureté (H) et le module de Young (E) tout au long de la phase de pénétration. Seize empreintes ont été réalisées sur différentes épaisseurs de tôle (0.4mm ; 0.7mm; 1mm et 1.5mm), sur chacun des deux constituants (couche Fe-Zn et substrat) ; celles réalisées sur le substrat servant à valider l’approche inverse à établir pour déterminer le comportement du revêtement

FRICTION AND WEAR BEHAVIOUR OF Ti-6AI-7Nb BIOMATERIAL ALLOY

Titanium and its alloys have been used as implant materials due to their very good mechanical and corrosion resistance and biocompatibility [1,2]. The most used biomaterials were commercially pure titanium (CP-Ti} issued in clinics, although CP- Ti has been pointed out to have disadvantages of low strength, difficulty for polishing, and poor wear resistance. Therefore, Titanium is still insufficient for high-stress applications ; e.g., long spanned fixed prostheses and the frameworks of removable partial dentures.Ti-6Al-4V alloy, originally developped as an aeronautical material, has been tested as a replacement for CP-Ti, because of its high mechanical properties with sufficient corrosion resistance[3], however, the cytoxicity of elemental Vanadium is questionable. Subsequently, some researches prove that vanadium and aluminum ions released from this ternary alloy can induce cytoxic effects or neurological disorders, respectively [4]. Also, for long-term, this alloy has transferred in sufficient load to adjacent bones, resulting in good resorbption and eventual loosening of the implant. Another ternary alloy used as implants was vanadium free, a+ii alloy, especially Ti-6Al-7Nb alloy that revealed improved mechanical characteristics, corrosion resistance and biocompatibility , developed for orthopedics application as a wrought material, has been evaluated as a new alloy for total hip prostheses. Niobium exhibits a similar effect to vanadium instabilizing ii phase in the Ti-Nb binary system, which is necessary for providing the a -ii two-phase structure. Therefore, niobium was used as the ternary element to produce the desirable microstructure in the Ti-6Al-7Nb alloy. Ascompared with Ti-6Al-4 V alloy, in a tensile test, these alloy show slightly lower strength and about 40% higher elongation

Etude des proprietes mecaniques des couches galvanisees par nanoindentation

Les revêtements industriels Fe-Zn constituent une large gamme des semi-produits de galvanisation en continu de tôles minces destinées à l’industrie de la carrosserie automobile. Ce revêtement, typiquement d’une épaisseur de l’ordre de 10 μm, résultant d’un traitement de post-galvanisation est constitué d’une phase êta, dzêta, delta et gamma (interface substrat/revêtement)

Friction and Wear Behavior of Ti-6Al-7Nb Biomaterial Alloy

Titanium has been increasingly applied to biomedical application because of its improved mechanical characteristics, corrosion resistance and biocompatibility. However their application remains limited, due to the low strength and poor wear resistance of unalloyed titanium. The purpose of this study is to evaluate the friction and wear behavior of high-strength titanium alloys: Ti-6Al-7Nb used in femoral stem (total hip prosthesis). The oscillating friction and wear tests have been carried out in ambient air with oscillating tribotester in accord with standards ISO 7148, ASTM G99-95a, ASTM G 133-95 under different conditions of normal applied load (3, 6 and 10 N) and sliding speed (1, 15 and 25 mm·s−1), and as a counter pair we used the ball of 100C 6, 10 mm of diameter. The surface morphology of the titanium alloys has been characterized by SEM, EDAX, micro hardness, roughness analysis measurements. The behav-ior observed for both samples suggests that the wear and friction mechanism during the test is the same for Ti alloys, and to increase resistance to wear and friction of biomedical titanium alloys used in total hip prosthesis (femoral stems) the surface coating and treatment are required

Effet de la température frittage sur le comportement mécanique et tribologique de l’alliage TiNi poreux

La biocompatibilité des implants est une condition indispensable à leurs usages. Elle peut être définie par la compatibilité entre un système technique et un système biologique. On distingue deux types de biocompatibilité, structurale et celle de surface. Elle est caractéristique de l’endommagement provoqué par l’implant sur les tissus. Cet endommagement est lié aux propriétés mécaniques de l’implant et aux produits libérés par le frottement et par la corrosion qui se manifestent à l’interface du biomatériau et des tissus environnants. Ces derniers peuvent être à l’origine de nombreuses irritations. A cet effet l’objectif de ce travail est l’étude de l’effet de la température de frittage sur le comportement mécanique, électrochimique et tribologique de l’alliage TiNi poreux

Synthesis, microstructural and tribological characterization of calcined nano-bioceramic α- al2o3, sintered at different temperatures

The current research was undertaken to study the improvement of the tribological behavior of nanocrystalline bioceramic, α-alumina sample, produced by the calculations of gibbsite at different temperatures (300 to 1200°C), followed by uniaxial pressing, sintering and HIP treatment. The improved friction and wear resistance is attributed to the fine microstructure of the sample calcined at 1400 °C

Tribological behavior of Ti-6Al-4V and Ti-6Al-7Nb Alloys for Total Hip Prosthesis

The aim of the study is to evaluate the friction and wear behavior of high-strength alloys Ti-6Al-7Nb used in femoral stem and compare it with a Ti-6Al-4V alloy cylindrical bar corresponding to ISO 5832-3 part 3/01-07-199 standard. The tribological behavior was investigated by wear tests, using ball-on-disc and pin-on-disc tribometers. These tests consisted of measuring the weight loss and the friction coefficient of samples. The oscillating friction and wear tests have been carried out in ambient with oscillating tribotester in accordance with standards ISO 7148, ASTM G99-95a, and ASTM G133-95 under different conditions of normal loads (3, 6, and 10 N) and sliding speeds (1, 15, and 25 mm·s−1). As counter pairs, a 100Cr6 steel ball with 10 mm in diameter was used. Results show that the two alloys had similar friction and wear performance, although their grain structures and compositions are different. Occurrence of large frictional occurred, is probably caused by formation and periodic, localized fracture of a transfer layer. Higher friction with larger fluctuation and higher wear rate was observed at the higher siding speed. The Ti-6Al-4V wear mechanism transforms from ploughing and peeling off wear at low sliding speed to plastic deformation and adhesive wear

Évaluation de la sensibilité du laminage aux modèles de comportement

Le travail présenté ici porte sur l'application au laminage des modèles de comportement récemment développés en plasticité grandes déformations en vue de la simulation numérique des procédés de mise en forme et notamment de l'emboutissage : modèle rigide plastique avec écrouissage isotrope, critère de Hill quadratique ou non-quadratique, plasticité associée ou non, viscoplasticité. Après avoir brièvement présenté ces modèles nous les intégrons dans le modèle classique de laminage (méthode des tranches, équation de Karman). La solution est obtenue en déterminant le point neutre par une méthode de tir. Ces modélisations sont ensuite illustrées par une analyse paramétrique de l'influence des divers paramètres constitutifs sur la réponse et une comparaison sur un matériau donné de différents modèles en exploitant les modèles identifiés par A. Khalfallah, A. Znaidi et A. Darsouni finalise ce travail