Liste des Mémoires de Master

Nombre total de résultats : 48
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Etude mécanique et microstructurale des soudures des alliages d'aluminium soudées par friction

Mémoire de Master

This work is related to the study of the friction welding process. This type of welding has many applications in different branches of industry. This process has many advantages. First, the very high quality assemblies can be made. In addition, this process is much faster than any other conventional processes. Furthermore, it can be completely automated so that constant quality is guaranteed. The aim of this study is the optimization of the parameters of friction welding: (by varying the friction time [s] and the rotational speed [rpm], forging time [s] and the friction pressure and forging [MPa] remain constant). An experimental procedure was used to obtain a welded junction (alu-alu), the alloy used is Al 6013-T8. We used several characterization methods, simple but effective and suitable for this kind of research work; such as microstructural characterization by optical microscope and mechanical characterization namely microhardness and tensile testing. We observed that the microstructure has three zones (TMAZ, HAZ and MDZ), The microhardness profile has a certain homogeneity and the tensile tests have shown that the tensile strength, elongation and elastic limit increase with increased friction time. In general, the mechanical properties are influenced by the overall effect of the metallographic structure of the weld. The latter is closely linked to the process parameters. Voir les détails

Mots clés : Friction welding, 6013-T8 alloy, Welded joint, mechanical properties, microstructure, Microhardness

Caractérisation et modélisation numérique d’un composite époxy/Alfa.

A. MOUHOUB  (2020)
Mémoire de Master

Nowdays, natural fiber composites are increasingly getting great interest on an industrial scale. This undeniable success is linked to the intrinsic properties of natural fibers reinforcements and to their ecological character. Our study consists in characterizing the mechanical properties in tensile, bending and ultrasonic as well as morphological characterization by optical and scanning electron microscopy in order to evaluate their aptitude to replace synthetic fiber composites. The material to be characterized is composed of an epoxy matrix reinforced with 20% in weight Alfa short fibers. Numerical modeling using the finite element method allowed us to predict the Young's modulus of our randomly reinforced biocomposites. The ANSYS modeling software was used to generate the 3D representative elementary volume and to calculate the Young's modulus of the composite. The experimental results recorded are close to those obtained by numerical modeling. The latter remains therefore the goal to reach. Voir les détails

Mots clés : natural fibers, Alfa fibers, biocomposites, mechanical characterization, numerical modeling, ecology

Conception et réalisation d’un système de contrôle non destructif par courant de Foucault pulsé

B. GHOBCHI Younes  (2020)
Mémoire de Master

The conventional EC method is used for near-surface defects finding [5] [48] [12] [2]. On the other hand, and in order to control great depths, pulsed eddy currents are used [35] [48] [12] [2]. Through this project we aim to realize an analogue-digital PEC-NDT system, interfaced by a microcomputer. A set of experiments is carried out in order to prove the sensitivity of the designed system towards some parameters [2], where the determined mechanical properties are compared with the results obtained in order to in order to confirm some hypotheses [32]. Voir les détails

Mots clés : cnd, Instrumentation, Courants de Foucault pulsés


M. BENTTOUMI  (2020)
Mémoire de Master

Aluminum has very low mechanical properties. To significantly increase them, we actedon three main modifying factors of the microstructure. Addition to aluminum of a very lowdensity element including 13% silicon which facilitates the flowability of the metal, gravitysand molding and structural hardening treatments.Al-Si alloys are highly indicated by their lightness, their high tensile and corrosionresistance. The study focuses on the influence of maturation on the evolution of the elasticproperties determined by the tensile and ultrasound tests of the Al-13% mass eutectic alloy. Iffor six states: raw casting noted - F and maturation in 6h steps noted - M0h, M6h, M12h,M18h and M24h. The parts produced from this alloy are part of the components used invarious projects by SNVI Rouïba and Electro-Industries de Fréha (covers, pump casing,motor pistons, etc.).All the results of the mechanical and structural properties gathered in Part III of our thesisshow us that we should recommend for the molding of parts whatever the series: the grossreference state designated - F. Voir les détails

Mots clés : Al-Si, sand, ripening, mechanical properties

Élaboration et caractérisation des céramiques supraconductrices YBa2Cu3O7

Mémoire de Master

This work presents bibliographic research and generalities about superconducting materials. The polycrystalline superconducting compound Y123 was developed by solid state reaction (powder metallurgy) from stoichiometric mixtures Y2O3, BaCO3, and CuO. To study the effect of the addition of lanthanum-doped cobalt ferrite (0-5-10%) on magnetic and optical properties, samples of 2g (99.9% Y123 and 0.1% CoFe2O4 (0-5-10%) lanthanumdoped) were prepared, and characterized by VSM and FTIR. Voir les détails

Mots clés : cuprates, supraconducter, Y123, YBCO, magnetic

Effet de l’application d’une peinture anti-corrosion sur le comportement électrochimique de l’acier au carbone en milieu acide

Mémoire de Master

In this work, we are interested in the evolution of the surface roughness of steel (mechanically polished (A2, A3) and shot-blasted (A2G, A3G)) and the thickness of the paint applied to different surface states (mechanically polished (A2P, A3P) and shot blasted (A2GP, A3GP)). Shows that the roughness of grit-carbon steel surfaces is greater than the mechanically polished ones. Although the evolution of the thickness of the paint deposited on mechanically polished and shot-blasted carbon steel, depending on the grade of polishing paper,), shows that the thicknesses of paint deposited on carbon steel surfaces shot blasted are larger than those polished mechanically. The characterization of the samples was determined by scanning electron microscopy (SEM), showing that the surface state of mechanically polished steel (A3) is much better than that of shot-blasted steel (A3G). The surface analysis by SEM also shows that the coatings applied on the shot-blasted steel (A3GP) have a much better morphology than those applied on mechanically polished steel (A3P), and the metallographic micrographic analysis shows that the thickness of the coatings of paints obtained on shot-blasted steel are superior than that obtained on mechanically polished steel, The effect of mechanical polishing and shot blasting on the behavior of carbon steel with respect to corrosion by the use of two electrochemical techniques: potentiodynamic method and electrochemical impedance spectroscopy (EIS). mechanically polished and shot-blasted steel with and without coating for better resistance to corrosion in hydrochloric acid medium. Spectral analyzes by FTIR, shows the evolution of chemical bonds and functional groups present in the paint applied to steel. Voir les détails

Mots clés : surface roughness of steel, shot-blasted steel (A3G), electron microscopy (SEM)

Etude et élaboration d’un nouveau procédé de traitement des effluents industriels contaminés par les métaux par électrodéposition

Mémoire de Master

Currently,Electrochemical methods find wide application in the treatment of industrial effluents to reduce their organic matter content, in inorganic sulphur compounds and nitrogen,or inharmful metals for the environment. Electrochemistry is not only applied to wastewater,but also on contaminated soils, incineration residuesor sewage sludge wastewater from the metallurgical industry. Electrochemistry has proved its effectiveness, which allowed him to integrate the environmental industry. Environmental electrochemical technologies allowto control pollution,to recycle materials,to carry out the rehabilitation of sites,monitoring (monitors and sensors for gases and liquids),the efficient conversion of energy, the prevention of corrosion, removal of contaminantsand disinfection of water. Electrochemical processes can therefore be efficient and economical when properly designed,and they integrate harmoniously with the environmental industry. These processes require compact installationsand can thus integrate into existing industrial waste treatment chains. The present work aims so the elaboration of an electrochemical process of treatmentand purification of industrial effluentscontaminate with metals. Indeed, the use of this technique can allow both the elimination of these metals by electroplating on a cathode,a recovery of metals, a saving of precipitation reagents and a reduction in the amount of sludge to be removed,as well as surface treatmentswhere the applications concern gold recovery, silver, copper, cadmium, nickel, zinc, iron and lead ... etc.The metal that can be recoveredin the form of valorizable cathodes,which allows the depollution of the environment. This work requires in-depth studies of design considerationsand the development of an electrolytic cell. Voir les détails

Mots clés : Electrochemical methods, inorganic sulphur compounds, inharmful metals

Conception d’une chaîne de visionembarquée sur une plateforme FPGA

L. HAKEM  (2019)
Mémoire de Master

Our work consisted of a strategic development for the design and implementation of an embeddedvision chain with the use of a smart camera. The implementation of our vision chain for the acquisition ofvideo data is essentially based on the EMBV Python1300C embedded vision kit. The implementation of areconfigurable architecture is based on the exploitation of a Xilinx Zynq 7020 FPGA SoC Voir les détails

Mots clés : embedded vision chain, EMBV Python1300C, FPGA, ZYNQ-7000

Élaboration et caractérisation des matériaux nanostructures à base de Fe et Ni

Mémoire de Master

The aims of this work is to understand the influence of the elaboration method , mill type, milling time and concentration on the structural, microstructural and magnetic properties of Fe80Ni20 nanostructured alloy. The production of the Fe80Ni20nanostructured alloy was carried out by the mechanical alloying technique of iron and nickel powders mixture. The elements produced (elaborated) were characterized by X-ray diffraction techniques (DRX), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The X-ray diffraction study confirmed the formation of the Fe-Ni alloy after 600 min of milling with an average crystallite size of 13 nm, while the analysis of the magnetization curves of the Fe-Ni alloys, revealed original magnetic properties: super paramagnetic behavior, and especially saturation magnetization and significant coercitivity. Voir les détails

Mots clés : elaboration method, properties of Fe80Ni20, nanostructured alloy

Apport des techniques de traitement de signal dans la localisation spatiale d’un défaut par ultrasons

Mémoire de Master

Le contrôle non destructif (CND) est une étape importante dans un processus industriel. Il permet de contrôler l’intégrité des composants sans les endommager, pendant ou à la fin de leur fabrication, et en situation d’utilisation. Différents phénomènes physiques permettent ces contrôles de par leur caractère pénétrant dans les objets (ondes électromagnétique, ondes acoustiques, champs magnétique, etc.), menant à différents modes de contrôle. Nous nous intéressons dans ce travail au CND par ultrasons, modalité qui consiste à émettre des ondes acoustiques dans le matériau a inspecté. Les ondes se propagent dans le milieu, et récupérées par le capteur ultrasonore, permettent dans la mesure du possible de détecter et d’identifier les défauts contenus dans la pièce. Le même procédé peut être appliqué pour évaluer les matériaux, c’est-à-dire pour estimer des paramètres physiques propres, tels que la vitesse des ondes ou le coefficient d’atténuation. Le but de l’utilisateur est de visualiser les échos et d’en déduire une information spatiale sur l’objet inspecté. Nous nous intéressons aux discontinuités, qui présentent des transitions franches dans l’objet (surface, arrêts, défauts, etc.). L’analyse du signal peut cependant se révéler difficile a l’œil nu pour plusieurs raisons : bruit, atténuation, diffraction, superposition d’échos, etc. L’allure des échos rétrodiffusés (réfléchis) du signal ultrasonore, lors d’une opération d’inspection, donne une indication sur la forme géométrique, la taille et l’orientation des réflecteurs se trouvant sur la zone étudiée. Une estimation correcte et précise de la forme des échos ultrasonores est essentielle pour déterminer les propriétés du milieu de propagation. Des techniques de traitement du signal sont alors employées pour améliorer la résolution des signaux. Dans ce travail nous nous intéressons à la localisation spatiale d’un défaut dans une pièce métallique en appliquant des techniques de traitement de signal. Voir les détails

Mots clés : CND par ultrasons, ondes électromagnétique, ondes acoustiques, champs magnétique