Liste des documents

Nombre total de résultats : 1994
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Elaboration par électrodéposition et caractérisation des couches minces de Ni/Si: Effet du potentiel de dépôt

A.Griche  (2022)
Mémoire de Master

Ni thin films deposited onto on n-Si (111) substrates using pulsed electrodeposition (PED) method show an influence of the applied potential and the Ni thickness on the structural, surface morphology, electrical and magnetic properties. Significant linearly increase in Ni thickness t (t ranges from 50 to 390 nm) has been observed with increasing applied potential (from -1.6 to -2.6 V). All samples show the polycrystalline films prefers growth with the <111> texture. The strain ε (%) is negative for all samples and their variation as a function of the applied potential has a critical value corresponding to a critical potential (VCr = -2.2 V); the stress increases up to VCr, then stress is relieved. The grain size increases monotonically with increasing Ni thickness and applied potential. Voir les détails

Mots clés : Ni thin films, electrodeposition, Structural properties, microstructure.

Etude de l’influence du traitement thermique sur les propriétés mécaniques et électrochimiques d’un rechargement E-309L / 316L-17 sur l’acier 25CrMo4

Mémoire de Master

The main concerns of industrialists having a relationship with the field of oil drilling is wear and corrosion a set of phenomena that act alone or in combination. We propose through this work in addition to the fact of making bi-materials by the hard reloading process to the MMA coated electrode (Manuel Métal arc), using the electrode E309L-17 in the first pass and 316L-17 in finish on low alloy chromium nickel 25CrMo4 steel, This type of steel is used during maintenance on borehole head preventers. In this welding configuration, see quality on the weld by discussing the effect of the chosen parameters on the cohesion at the substrate-input metal and the optimization of the welding process. Three essential steps to be considered in this study: the production of bi-materials by MMA reloading, microstructural, mechanical characterization of compounds and the electrochemical study in NaCl has 3.5% Voir les détails

Mots clés : 25CrMo4, Interface, reloading, corrosion, tribology, heat treatmen

Elaboration et caractérisation et applications des nanoparticules Bi-M par la méthode de Co-précipitation

N.H.BOUHAL, M.TALI  (2022)
Mémoire de Master

Research around nanoparticles (NPs) is very popular in the scientific community. This thesis consists in developing bismuth iron (BiO) nanoparticles by the Co-precipitation method, under an experimental protocol and under different temperature and PH conditions , then these nanoparticles were characterized by different analysis techniques: FTIR infrared spectroscopy, X-ray diffraction (XRD), and UV-Vis spectroscopy; then to use the nanoparticles for the application to the adsorption of the dye (Methylene blue, Naphthol blueblack, bromophenol blue and posceau s extra). Voir les détails

Mots clés : X-ray diffraction (XRD), and UV-Vis spectroscopy;, UV-Vis spectroscopy, FTIR infrared spectroscopy

Simulation du comportement et de l’endommagement mécanique d’un matériau composite sandwich

Mémoire de Master

This work is dedicated to the study of an advanced approach based on the modeling of the behavior and damage of the glass/epoxy sandwich composite in polyether imide core under tensile and shear loading. In particular, we are interested in the study of the damage coupled to the rupture of this sandwich composite. These sandwich composites are used in fields such as aeronautics and automotive. Their uses call for the development of reliable constituent models to predict their responses under complex loading conditions. This model considers all damage in the plane: damage caused by cracking of the epoxy matrix as well as damage due to the rupture of the glass fabrics in the longitudinal and transverse directions. For this study a model has been designed as two layers plus one PEI layer [0°/90°]. For this purpose various experimental results were established in order to develop a model for damage analysis, whose composite response is governed by a coupling between damage and failure. In order to develop this study, we used finite element software (ABAQUS/Standard), by which we proceeded to obtain simulation results presented in this work and thus, correctly predict the static response obtained by the experimental measurements. Voir les détails

Mots clés : modeling, thermo set matrix sandwich composite, mechanical behavior, tensile test, Stress, Strain, deformation, damage, breakage.

Caractérisations microstructurale et mécanique de soudures hétérogènes (2205/X52) réalisées par friction rotative : Effet de temps de friction

Mémoire de Master

This work consists of joining two different materials grades, the dual phase SAF 2205 duplex stainless steel and an API X52 high strength low alloy (HSLA) steel using the solid state welding process (Rotary Friction). The aim of this experimental work is to study the friction time effect on microstructural evolution of the obtained heterogeneous joints and identify the different zones affected by this process. A mechanical characterization is also planned in this study, in order to highlight the consequences of friction time on some mechanical properties through hardness, microhardness and tensile tests. Voir les détails

Mots clés : SAF 2205, duplex stainless steel, API X52, tensile tests

Approche expérimentale et théorique de l’inhibition de la corrosion de l’aluminium en milieu alcalin

S. AMMI, D. AIT AOUDIA  (2022)
Mémoire de Master

The objective of this thesis is the study of the properties of the cocamidopropyl betaine surfactant. The CPAB has been evaluated as a corrosion inhibitor of the aluminum used in the AL-Air batteries in KOH 1M, by means of the open circuit potential (OCP), of curves dynamic potential polarization of TAFEL and measurements by electrochemical impedance spectroscopy. The results revealed that the processus is limited by pure activation, that the CPAB inhibitor behaves as an effective cathodic inhibitor and that the inhibitory efficiency obtained from the different methods increases with increasing inhibitor concentration. The adsorption of the inhibitor on the aluminum surface follows Langmuir adsorption indicating monolayer adsorption. The theoretical study showed that the Cocamidopropyl betaine could serve as an effective corrosion inhibitor for aluminum in an alkaline solution. Voir les détails

Mots clés : inhibitor, corrosion, aluminum, curves dynamic potential polarization of TAFEL, EIS, CPAB.

Elaboration et caractérisation des nanoparticules Ferrite/ Mg/Mn par co-précipitation

B. Ouali  (2022)
Mémoire de Master

Nanosciences and nanotechnologies have experienced great growth over the past fifteen years, thanks to the development of new tools for elaboration, observation and analysis. This thesis focuses on the development of iron-based nanoparticles by the coprecipitation method with an experimental protocol and under different temperature and pH conditions. The characterization of the phases was carried out by X-ray diffraction, Infrared spectroscopy with Fourier Transform FTIR and Ultraviolet-visible spectroscopy. Voir les détails

Mots clés : Nanosciences and nanotechnologies, iron-based nanoparticles, X-ray diffraction

Etude de la soudabilité de l'alliage d'aluminium 7075 soudé par le procédé de soudage par point par friction malaxage FSSW

Mémoire de Master

The welding of metal structures and constructions in various industrial sectors is tending towards the intensive use of modernized welding processes such as FSSW. In order to reduce the weight of metallic devices and structures, the replacement of riveting by welding is considered in the current research. In the present work, the interest will be focused on the study of this process. Sheets in AA7075-T6 are welded using different speeds of rotation and depth of penetration, we have used several simple but effective analytical methods suitable for this type of research, such as mechanical tests, such as tensile tests and hardness tests, to determine the best properties for a good weld that can maintain the mechanical properties of the base materials. We also conducted a microscopic study to detect the different zones in welding position, and we reached zones, which are ZM ZAT ZATM These zones result from the heat generated by the friction that occurs between the welding tool and the aluminum plates. We show that increasing the speed of rotation and the depth of penetration of pawn increases the resistance of the weld joint. So we obtain a tensile force equal to 2.03 kN at a speed of 1800 rpm and a penetration value of 3.4 Voir les détails

Mots clés : ZM ZAT ZATM, welding of metal structures, FSSW, AA7075-T6

Conception et réalisation d’un système d’imagerie ultrasonore commandé par carte FPGA

Mémoire de Master

This research will be built on the study, the conception and the software and hardware realization of a micrometric displacement system with three axes, controlled by FPGA board. This system allows a scanning of the parts by ultrasonic transducers. The acquired ultrasound signals are sent to a PC for processing and exploitation. This work also consists in implementing algorithms on MATLAB allowing to constitute ultrasonic images and to process them in order to detect and locate the possible defects (ex.cracks) in the examined parts. Voir les détails

Mots clés : micrometric displacement, FPGA board, ultrasound transducers

Caractérisation microstructurale et micromécanique d’unassemblage X60/316L, réalisé par Cladding, après déformation par laminage à chaud.

I. AOUIDAD, S. SIAD  (2022)
Mémoire de Master

The objective of this work is to study the behavior of an assembly composed of a high yield strength steel and an austenitic stainless steel made by the cladding process under the effect of hot working followed by recrystallization annealing. Microstructural and micromechanical characterizations were performed on the whole multi-material and at the interface. In the present work, we have highlighted the importance of understanding and mastering the aspects of phase transformation and recrystallization mechanisms in order to optimize the mechanical properties by thermal and/or thermomechanical treatment. Voir les détails

Mots clés : Cladding, HSLA steel, stainless steel, thermomechanical treatment, recrystallization, phase transformation, Microhardness, annealing.