Liste des Mémoires de Master
Préparation et caractérisation des nanoparticules de ferrite de nickel dopée au Cérium par la méthode de coprécipitation
Nanocrystalline powders of cerium-doped nickel ferrite were synthesised by the coprecipitation method and the effect of the non-magnetic cerium content on the structural and magnetic properties was studied. X-ray diffraction (XRD) was used to determine the structure of NiFe2O4 nanoparticles. The surface morphology and chemical composition of the NiFe2O4 nanoparticles were obtained by scanning electron microscope analysis. The magnetic properties were studied by Vibrating Sample Magnetometry (VSM). Magnetic hysteresis cycles were measured with a maximum applied magnetic field of ≈ 1000Oe Voir les détails
Mots clés : NiFe2O4, cerium, co-precipitation, Magnetic Properties, DRX, SEM, VSM
Simulation du comportement et de l’endommagement mécanique d’un matériau composite sandwich
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.
Conception d’un autopilote pour un drone léger type quadri-rotor
This dissertation is divided into two important parts: the first part is dedicated to the establishment of the dynamic quadrotor model to study its stability and control under MATLAB. The second part is reserved for the realization of an autopilot card for the quadrotor that should be compatible with Arduino MEGA development board. This card must be able to acquire and process information from the MPU6050 and GPS sensors in real time, to order and control the quadrotor. The results obtained by the sensors must be displayed on a graphical interface representing the ground station. Voir les détails
Mots clés : Quadrotor, autopilot, Arduino MEGA, GPS, MPU6050, ground station, real time, MATLAB.
Etude du pouvoir inhibiteur de l’extrait de la Spergularia ruba(sabline rouge) vis-à-vis de la corrosion de l’acier X70 dans une solution acide HCl 1M
Some organic compounds are considered as effective inhibitors for the corrosion of steels in the acid medium, when they are added in low concentrations; they can reduce or stop the corrosion of the exposed metal. Their operating principle is based on the protection of the metal of its environment. In this work we were interested in the study of the effect of the Spergularia ruba extract on the corrosion of X70 steel in a molar solution of hydrochloric acid at 25 ° C. Inhibitory efficiency and mode of action were evaluated by both gravimetric and electrochemical methods. The results obtained showed that the efficiency exceeds 82% for a maximum concentration of 560 mg / L, and increases with immersion time at room temperature. Voir les détails
Mots clés : acid corrosion, steel, inhibition, green inhibitor, Spergularia ruba
Elaboration des nanoparticules métalliques par co-précipitation et caractérisation structurale
Nanoparticles are now part of everyday life; researchers have developed new tools with their structural and magnetic properties interesting for various fields ranging from health as well as the environment. The objective of this study is the elaboration of metallic nanoparticles in order to optimize the working conditions and the properties of these nanoparticles, and the structural and magnetic characterization. We used a weakest and least expensive synthesis method that co-precipitates. We found that pH value, working temperature, and precursor nature influence particle size, morphology, chemical composition, and magnetic behavior. We have shown that increasing pH, temperature, and sulfide-type precursor utilization decreased the size of nanoparticles and led to improved properties such as chemical composition, morphology, and saturation magnetization. Voir les détails
Mots clés : metallic nanoparticles
Effet de déformation par pliage sur le comportement à la corrosion de l’acier duplex 2205
The effect of cold deforming by folding on the microstructure and corrosion behavior of austenoferritic stainless steel (duplex 2205) has been studied in this work. Duplex 2205 offers a good compromise between the toughness of austenitic steels and the mechanical and corrosion resistance of ferritic steels. We deformed the duplex steel by bending it at different levels (12, 25, 40 and 50%). The effect of the deformation on the microstructure and mechanical properties was investigated by the various experimental technics; microhardness; metallography, SEM. The relationship between increasing deformation and corrosion resistance was investigated by electrochemical tests. The results showed that cold working modifies the internal microstructure of both phases and that high cold forming rates have a detrimental effect on the corrosion resistance of duplex steels. Voir les détails
Mots clés : deformation, duplex, corrosion, Austenite, Ferrite, Resistant, Folding
Etude expérimentale des vitesses et d’atténuation d’un polymère semi cristallin PEHD par des méthodes ultrasonores
Semi-crystalline polymers are materials that permeate our daily lives, and are used in a wide range of applications, generally when viscoelasticity is required. Therefore, numerous works of research have been conducted these last years to study their elastic properties. Since then, we propose the use of nondestructive analysis techniques based on detecting and spreading ultra sound waves with both immersion and contact. The results obtained on the analyzed materials presents us with good estimates judged to be very satisfying compared to literature. Measures of the velocity and mitigation of longitudinal and transverse ultra sound waves have been conducted on two samples of different thickness of a semi-crystalline polymer of the type PEHD. The experiments have been conducted in ambient temperature. The objective is the characterization of this polymer using ultra sound waves. Voir les détails
Mots clés : Ultrasounds, Velocity, Attenuation, echoes, transmission, polymers.
Influence de l’énergie de soudage sur la microstructure et la résistance à la corrosion de l’acier inoxydable Lean duplex UNS S32101
Duplex stainless steels are widely used in industry, because their two-phase structure with equivalent fractions in austenite and ferrite gives them very interesting mechanical properties and high resistance to different types of corrosion. However, the use of these steels is limited by their sensitivity to the formation of hazardous intermetallic phases with adverse effects on hardness and corrosion resistance. It is a weakening of the material that is visible under certain welding conditions. The subject deals with the study of a welding process applied Lean duplex stainless steel, LDX 2101 to a nickel-reduced stainless steel and aims to show the influence of the experimental parameters (03 energies) on the microstructural and stress corrosion resistance properties ( CSC) of the weld joint Voir les détails
Mots clés : Lean duplex stainless steel, LDX 2101, welding energy, stress corrosion cracking (SCC)
Effet des traitements thermiques sur le comportement microstructural et mécanique de l’acier inoxydable Lean duplex 2101 lors du vieillissement
As part of this project of memory we propose by this work a study on the microstructural and mechanical behavior of a stainless steel Lean Duplex LDSS 2101 during heat treatments realized in two stages: a treatment of dissolution at a temperature of 1050 ° C for one hour then water quenching, followed by an aging treatment at 720 ° C at different holding times (T = 10min, 60min, 10h, 24h, 120h, 240h) followed by quenching to water.The different samples are metallurgically characterized by optical microscopy and scanning electron microscopy (SEM). XRD analysis was used to identify the phases and precipitates formed during the treatments. Thermal treatments have significantly affected the phase equilibrium of stainless steel, caused by nitrides and carbides precipitation phenomena.Micromechanical characterization was performed by nano-indentation tests for the measurement of hardness and Young's modulus for each phase for the different samples. Voir les détails
Mots clés : stainless steel Lean Duplex LDSS 2101
INFLUENCE DES TRAITEMENTS THERMIQUES SUR LES ROPRIETES DE L’ALLIAGE D’ALUMINIUM 2XXX ET LECHAMP DE DEFORMATION
The main objective of our work is to study the influence of the thermal treatment of structural hardening, we will choose Aluminum alloy (Al-Cu-Mg) of the series 2XXX, which is obtained in the form of thin plate (1.97 mm). The nuance, heat treatment history and alloy properties are unknown. The study was based on a complete characterization with the metallurgical and mechanical components ending in a correlation of the two to lead to the fracture facies. The results, based on scanning electron and optical microscopy, X-ray diffraction, tensile testing, micro hardness, and ICD, guided us to identify the influence of thermal treatments on the fracture behavior that can change from a brittle to the initial state and from a ductile to brittle to the treated state. Voir les détails
Mots clés : thermal treatment, Aluminum alloy (Al-Cu-Mg)