Liste des Mémoires de Master

Nombre total de résultats : 48
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Elaboration et caractérisation des composites stratifiés à base de fibres de carbone et de fibres de verre à usage aéronautique

A. r. OUKAZI  (2019)
Mémoire de Master

This work is based on the elaboration and the characterization of different types of laminated composites based on epoxy resin, carbon fiber and glass fiber. These composites differ based on three essential parameters, including the type of reinforcements used, the orientation of the constituent fibers reinforcements and the heat treatment temperature at which these laminated composites were exposed. The characterization is then done to see the influence of these elaboration parameters on the physical and dynamic behaviors of this laminated composite materials developed during and after the solicitation. For this, we used nondestructive testing methods such as ultrasound and microscopy and destructive methods such as tensile and bending tests. The results obtained from the various tests were the subject of comparative interpretations followed by interesting perspectives. Voir les détails

Mots clés : Laminated composites, carbon fiber, Glass fiber, Epoxy resin, nondestructive test, mechanic tests

Détection, positionnement, localisation et identification des défauts dans les matériaux solides par ultrasons

L. GHOUDELBOURK  (2019)
Mémoire de Master

In this study, we have been adapted to the various techniques of non-destructive testing and especially non-destructive ultrasonic testing by contact of a piezoelectric transducer with welded parts (different types of welding). This method can detect, locate, dimension and identify defects in the weld seam after going through several steps such as calibration and tracing of the distance amplitude curve. The ultimate goal of this control is to accept or reject controlled parts according to international standards Voir les détails

Mots clés : Non-Destructive testing, piezoelectric transducer, different types of welding

Contrôle du joint de soudure d’un pipeline par ultrasons

L. GHOUDELBOURK  (2019)
Mémoire de Master

In this study, we have been adapted to the various techniques of non-destructive testing and especially non-destructive ultrasonic testing by contact of a piezoelectric transducer with welded parts (welded pipe). This method can detect, locate, dimension and identify defects in the weld seam after going through several steps such as calibration and tracing of the distance amplitude curve. The ultimate goal of this control is to accept or reject controlled parts according to international standards Voir les détails

Mots clés : Non-Destructive testing, - ultrasonic testing, welded pipe

Etude des propriétés mécaniques et magnétiques des alliages Fe70Al30-xSixélaboré par arc melting

M. CHETTAH  (2019)
Mémoire de Master

This study investigates the effect of Al substitution by Si on the structural, mechanical (Vickers HV hardness) and magnetic (hysteresis loop) properties of the Fe70Al30-xSix alloys developed by Arc Melting.Results show that the increase in Si content gives rise to the ordered phase DO3 (FeAl0.7Si0.3) starting from the composition Fe70Al15Si15; this last transition is accompanied by a drop in micro hardness HV and a remarkable variation in structural parameters such as relaxation of the crystals. Also, the substitution of Al by Si atomes decreases the cell parameter.Our choice of process and alloy is based on economic considerations (low cost) to understand the phase transitions in these alloys that are typical ones. Voir les détails

Mots clés : Fe-Al-Si alloys, Arc melting, Order-disorder transitions, solid solution bcc-Fe, Ordered phase DO3 (Fe3Al0.7Si0.3), micro-hardness HV, Hysteresis cycle, Coercive field, Remanent magnetization, Saturation magnetization

Étude ab-initio dans le cadre de la DFT des propriétés structurales et physiques de supraconducteur à haute température critique (SHTc) de type pnictides de fer (FeSe)

M. CHETTAH  (2019)
Mémoire de Master

In this work, we presented a study on the structural, elastic, electronic, magnetic and optical properties of iron selenide. The calculations were performed by the Pseudo-Potential method which is based on density functional formalism (DFT), using local density (LDA) and generalized gradient (GGA) approximations. The doped (GdFeSe and CeFeSe) and undoped (FeSe) structural properties such as the mesh parameters (a, b and c) and the compressibility modulus, are calculated as a function of pressure and the results found are in agreement with those advanced by the experimental and other calculations. In the study of the electronic properties of FeSe, the energy gap value calculated with the GGA approach are in agreement with those of other calculations. As far as the elastic properties are concerned, we calculated the elastic constants with the GGA approach and the found values of the latter are very close to those of the experiment. We also calculated the magnetic moment and confirmed that FeSe is a non-magnetic material. For the optical properties, we calculated the different optical properties such as the function of the reflectivity, the refractive index and the absorption coefficient. Voir les détails

Mots clés : Superconductivity, pnictures, FeSe, DFT, pseudo potential, Castep

INFLUENCE DES TRAITEMENTS THERMIQUES SUR LES ROPRIETES DE L’ALLIAGE D’ALUMINIUM 2XXX ET LECHAMP DE DEFORMATION

B. CHAOUCHE, K. MIMOUNI  (2019)
Mémoire de Master

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)

Effet des traitements thermiques sur le comportement microstructural et mécanique de l’acier inoxydable Lean duplex 2101 lors du vieillissement

R. Bourahla, A. Labadlia  (2019)
Mémoire de Master

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 de l’énergie de soudage sur la microstructure et la résistance à la corrosion de l’acier inoxydable Lean duplex UNS S32101

K.KHELIL, M.SADOUNE  (2019)
Mémoire de Master

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)

Etude expérimentale des vitesses et d’atténuation d’un polymère semi cristallin PEHD par des méthodes ultrasonores

R.Daha, D.Chehaoui  (2019)
Mémoire de Master

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.

Effet de déformation par pliage sur le comportement à la corrosion de l’acier duplex 2205

M.Meyssoune, K.MENNA  (2019)
Mémoire de Master

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