Дисертації з теми "Déformation microscopique"
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Raynaud, Suzanne. "Fracturation et dissolution sous contrainte des roches : aspects naturels et expérimentaux à l'échelle microscopique." Aix-Marseille 1, 1995. http://www.theses.fr/1995AIX11072.
Повний текст джерелаCheval, Florence. "Étude comparative des déformations statique et dynamique du cuivre polycristallin : aspects macroscopique et microscopique." Paris 11, 1988. http://www.theses.fr/1988PA112394.
Повний текст джерелаEl, Mayas Theet Nathalie. "Modélisation microscopique et macroscopique du comportement d'un composite à matrice métallique." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1994. http://tel.archives-ouvertes.fr/tel-00523623.
Повний текст джерелаChicois, Jean. "Etude des mécanismes microscopiques de la déformation cyclique." Lyon, INSA, 1987. http://www.theses.fr/1987ISAL0008.
Повний текст джерелаAlvo, Sébastien. "Etude, modélisation et mesure des forces d'adhésion à l'échelle microscopique." Paris 6, 2012. http://www.theses.fr/2012PA066563.
Повний текст джерелаThe behavior of microsized objects is governed by surface effects. Reliable interaction models between micro-objects and robots end-effectors are required for micromanipulation. Numerous parameters are involved in adhesion forces modeling. The influence of each of these parameters must be determined in order to control forces and especially the one which is required to split to contacting objects: the pull-off force. Moreover, at the microscale, measurements of interaction forces during a manipulation task are complex and are only available in few cases. The general approach of this work can be divided into three main steps. After a presentation of the micromanipulation context, models and measurement tools of the literature are depicted in the first step (chapter 1). Two modeling approaches are highlighted; where strengths and weaknesses of models are focused in chapter 2 in order to develop a new adhesion forces model during the second step (chapter 3). This model highlights coupling between local deformations and adhesion forces and exposes major differences between microscale and nanoscale. Finally, the objective of the third step is the correlation of the proposed model with experiments. The analysis of experimental results is presented in the chapter 4. The results show the difficulties encountered for modeling interactions between real micro-objects and highlights a scale effect on electrostatic forces
Azzaz, Mohamed Shaker. "Étude par microscopie électronique des fautes d'empilement et des macles dans le phosphure d'indium déformé." Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL116N.
Повний текст джерелаBéché, Armand. "Mesure de déformation à l'échelle nanométrique par microscopie électronique en transmission." Phd thesis, Grenoble INPG, 2009. http://tel.archives-ouvertes.fr/tel-00489867.
Повний текст джерелаCoupeau, Christophe. "Etude in situ de la déformation plastique par microscopie à force atomique." Poitiers, 1997. http://www.theses.fr/1997POIT2255.
Повний текст джерелаGuétaz, Laure. "Étude par microscopie électronique haute résolution de la déformation d'un superalliage Ni-Co." Grenoble INPG, 1993. http://www.theses.fr/1993INPG0142.
Повний текст джерелаAlvo, Sébastien. "Étude, modélisation et mesure des forces d'adhésion à l'échelle microscopique." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00772533.
Повний текст джерелаOmri, M'Barek. "Étude des mécanismes de déformation plastique dans le composé III-V GaSb monocristallin." Vandoeuvre-les-Nancy, INPL, 1987. http://www.theses.fr/1987NAN10313.
Повний текст джерелаVoegele, Violaine. "Etude en microscopie électronique en transmission de la plasticité des grenats silicates." Lille 1, 1998. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1998/50376-1998-133.pdf.
Повний текст джерелаThurel, Elina. "Etude par microscopie électronique en transmission des mécanismes de déformation de la wadsleyite et de la ringwoodite." Lille 1, 2001. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2001/50376-2001-111-112.pdf.
Повний текст джерелаCastany, Philippe. "Etude des micromécanismes de déformation d'un alliage Ti-6Al-4V par déformation MET in situ : influence d'un traitement de surface." Toulouse, INSA, 2007. http://eprint.insa-toulouse.fr/archive/00000200/.
Повний текст джерелаTi-6Al-4V is the most used titanium alloy in aeronautics because of its low density combined with excellent mechanical properties. However, the elementary mechanisms of deformation responsible for mechanical properties of Ti-6Al-4V alloys are not yet well understood. To provide a better knowledge of these micromechanisms is the main purpose of this work. As this alloy has relatively bad surface properties, particularly regarding mechanical wear, we are also interested in modifications induced by a protective surface treatment (nitridation). Numerous in situ transmission electron microscope (TEM) tensile experiments have been performed during this study. They have allowed us to determine that the strength is mainly due to the core structure of screw dislocations with a-type Burgers vectors and that short range order (SRO) has a non negligible effect in the deformation of nodules. The role of the different interfaces has been also clearly enlightened. Concerning the surface treated alloy, post mortem observations of pre-deformed samples show that the nano-crytallised layer at the surface is a barrier for the propagation of dislocations. In the diffusion layer SRO evolves to the formation of long range ordered nano-precipitates leading to a more localised deformation. Finally, an in situ TEM tensile experiment has been performed for the first time on a cross-section sample prepared with an original way using a FIB
Fabbri, Filippo. "Déformation photoinduite dans les films minces contenant des dérivés d'azobenzène : effets de polarisation, de proximité et de contact." Palaiseau, Ecole polytechnique, 2009. http://pastel.archives-ouvertes.fr/docs/00/52/73/88/PDF/Thesis.pdf.
Повний текст джерелаIn this work we use direct local-probe techniques to study the photomechanical phenomena induced at micro- nanoscale in photochromic thin films containing azobenzene molecules. We show the existence of different mechanisms at the origin of the photo-induced deformation and their crucial dependence on the spatial distribu- tion of the light field polarization and intensity, which allows to coherently interpret far-field and near-field photo- deformation phenomena so far observed. Moreover, we investigate the near-field deformation effects due to the interaction between the local probe and the sample surface. Finally, we present preliminary studies of the photo- mechanical effects in layered hybrid metal/azo-polymer structures which open perspectives in view of applica- tions in the fields of nano-fabrication and nano-actuation of thin films and surfaces
Détrez, Fabrice. "Nanomécanismes de déformation des polymères semi-cristallins : étude in situ par microscopie à force atomique et modélisation." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10070/document.
Повний текст джерелаThe aim of this work is to study the nano-scale deformation mechanisms within the spherulitic structure of semi-crystalline polymers. The deformation mechanisms are imaged by atomic force microscopy. The originality of this work is the use of a home-made tensile drawing stage under the AFM head in order to perform in situ tensile tests. The observations performed on several semi-crystalline polymers (polyamide 6, polybutene, polycaprolactone) revealed fragmentation of crystalline lamellae and micro-crazing. These mechanisms appear from the end of elastic stage, and induce permanent deformation and degradation of mechanical properties. These experimental observations enable assuming that there is a coupling between plasticity and damage. The viscous contribution is first identified, then subtracted from the data of cyclic tensile tests in order to assess the damage and the plastic deformation. The damage evolution follows the same law for the various materials in spite of their large structural differences (lamellar thickness, spherulite diameter, glass transition temperature ... ). The mechanical behavior modeling based on the concept that the semi-crystalline polymers consist of a macromolecular network flanged by the crystalline structure. The behavior law has been developed with this concept including the damage law previously identified. This law has been implemented in a finite element program. Good fits of the experimental monotonic and cyclic tensile tests have been obtained together with fairly good predictions of the relaxation behavior of three studied materials
Farenc, Sylvie. "Etude des mécanismes de déformation du titane et de l'alliage TiA1." Toulouse 3, 1992. http://www.theses.fr/1992TOU30052.
Повний текст джерелаEscale, Nicolas. "Étude par microscopie électronique en transmission des microstructures et des micromécanismes de déformation d'alliages de titane béta-métastables." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/2509/.
Повний текст джерелаThe lightening of structure is one of the most important issue in the aircraft industry. The weight saving for future planes could be obtained by the use of materials with very high specific mechanical performances. Titanium alloys have high mechanical properties, a relatively low density, an high damage tolerance and corrosion resistance are particularly interesting to reach this purpose. The aim of this present work is to characterize and understand the fundamental micro-mechanisms of deformation in two titanium alloys: Ti 5553 (Ti-5Al-5Mo-5V-3Cr) and Ti 17 (Ti-5Al-2Sn-2Zr-4Mo-4Cr). These two alloys seem to be good candidates to substitute the Ti64 alloy, which is the aeronautical industry reference. To carry out this study we have characterized by Transmission Electron Microscopy the microstructure, which consists in hexagonal phases embedded in a cubic centered matrix. In situ straining TEM experiments combined with conventional and High Resolution observations allow us to identified and quantified the micro-mechanisms of deformation that influence the plasticity in these materials. So we have determined that the strength is due to several contributions like: a structural hardening, the presence of a local order or the core structure of screw dislocations
Milhet, Xavier. "Plasticité et dislocations du nitrure de silicium de structure bêta ; étude par microscopie électronique en transmission." Poitiers, 1999. http://www.theses.fr/1999POIT2256.
Повний текст джерелаPetitgrand, Sylvain. "Méthodes de microscopie interférométrique 3D statiques et dynamiques pour la caractérisation de la technologie et du comportement des microsystèmes." Paris 11, 2005. http://www.theses.fr/2005PA112235.
Повний текст джерелаThe microelectromechanical systems (MEMS) rely on the generation and/or detection of deformations, motions and vibrations of thin microstructures having lateral dimensions in the micrometer to millimeter range. Ex situ characterization of the technology and (thermo)mechanical behaviour of these MEMS needs non contact measurement methods having a (sub)micron lateral resolution and a (sub)nanometer vertical resolution. In this work we developped, within the frame of a collaboration with Fogale nanotech company, different interferometric profilometry and vibrometry techniques with continuous or stroboscopic, monochromatic and white light, illumination, based on interference microscopy. These methods allow full field and 3D measurements of the surface topography and of out-of-plane and in-plane vibration modes of microstructures as well as their transient response, their spectral reflectivity map and a mapping of thickness and refractive index of transparent films and devices. The performances and limitations of these methods are analyzed and illustrated on different micromachined surfaces, micromechanical devices and MEMS arising from public and industrial, french and foreign laboratories
Gentzbittel, Jean-Marie. "Mécanismes microscopiques de la déformation cyclique des alliages binaires aluminium-lithium. Mise en évidence d'un phénomène d’instabilités mécaniques, relation avec la microstructure." Lyon, INSA, 1988. http://www.theses.fr/1988ISAL0036.
Повний текст джерелаAndroussi, Yidir. "Mécanismes de déformation plastique de l'Arséniure de Gallium sous très forte contrainte et à température ambiante." Lille 1, 1988. http://www.theses.fr/1988LIL1A001.
Повний текст джерелаMichel, Jonathan. "Caractérisation par UHV AFM/STM des nanostructures de déformation de l'intermétallique Ni3Al." Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2321/document.
Повний текст джерелаNi3Al intermetallic compounds, that correspond to the strengthening phase of nickel-based superalloys, are well known to exhibit within a given range of temperature, an anomalous behaviour of flow strength. This positive temperature dependence of flow strength, called yield stress anomaly (YSA), has been the subject of extensive experimental studies concerning mechanical properties and dislocation microstructures, which have yielded several plausible models. Most of these models considers that a thermally activated cross-slip process, from the primary {111} onto the cube cross-slip {010} planes, plays a key role in the understanding of the YSA. However, the height of the cross-slipped segment in the {010} plane can be drastically different. The slip traces resulting from the emergence of moving dislocations at the surface in plastically deformed samples, allow us to visualize cross-slip events and to characterize the elementary mechanisms controlling plastic deformation. The number, height and length of slip traces corresponding to {111} and {010} planes, that are key parameters for modelling the plastic behaviour of Ni3Al intermetallic, are examined. These parameters reflect both the source activity and dislocation mean free path of dislocations; their values suggest that the YSA takes place with a strong exhaustion of mobile dislocations. Several larger deviations on the {010} planes, as well as double cross-slip between {111} neighbouring planes, are highlighted. These results suggest two different cross-slip process
Feregotto, Virginia. "Observation par microscopie électronique en transmission des défauts étendus introduits par déformation à haute température dans le nitrure d'aluminium." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL142N.
Повний текст джерелаGaume, Marine. "Etude des mécanismes de déformation des alliages de zirconium après et sous irradiation." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30220/document.
Повний текст джерелаIn Pressurized Water Reactors, the neutron flux leads to a change in the mechanical properties of the fuel cladding tubes made of zirconium alloys. Although their macroscopic behavior is well known, the microscopic deformation mechanisms of zirconium alloys still need to be characterized. In order to simulate the neutron irradiation, charged particles irradiations (ion and electron) were carried out at 400°C and 450°C on a zirconium alloy: RXA Zircaloy-4. The experimental analysis of the irradiated microstructure, performed by using a Transmission Electron Microscope (TEM), have shown some crystalline defects: dislocation loops with a Burgers vector. Their evolution (size and density) and their characteristics (nature and habit plane) have been determined and discussed based on the point defects diffusion. The results suggest a weak anisotropy in the self-interstitial diffusion. In-situ tensile tests were performed using a TEM, after ion irradiation, in order to activate the dislocation glide and to observe their interaction with the loops. Some of the experimental cases of interaction have been simulate using Dislocation Dynamics for a better understanding of the mechanisms. The simultaneous effect of the stress and of the irradiation on the deformation mechanisms have been then studied. In-situ electron and ion irradiations were conducted, with and without an applied stress. Deformation mechanisms involving dislocation climb have thus been demonstrated. Through this study, models based on the identified mechanisms may be suggested, in order to predict the behavior of zirconium alloys in the reactor
Perrin, Pierre-Yves. "Réarrangements et auto-organisation induits par une déformation dans une émulsion concentrée." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066319/document.
Повний текст джерелаThe concentrated emulsions are disordered compact packing of droplets of oil in water. As in the case of colloidal suspensions or foams, their rheological behavior is that of a Herschel-Bulkley liquid. On the microscopic scale, the flow is explained by plastic and localized rearrangements of the oil droplets. The objective of this thesis is to characterize and understand these microscopic dynamics. By adapting the Diffusing Wave Spectroscopy (DWS) technique, we have developed a time and space resolved detection technique for the plastic rearrangement of droplets . Concentrated, non-Brownian emulsions were developed by membrane emulsification. An osmotic device allows us to monitor in situ the confinement pressure of our samples. We have probed the rearrangements of droples triggered by applying to our samples uniaxial deformations of controlled amplitudes. We have observed the presence of plastic rearrangements even at the smallest amplitudes of deformations
Tattevin, Hélène. "Déformation et transformation de phase induites par ondes de choc dans les silicates. Caractérisation par la microscopie électronique en transmission." Phd thesis, Université Rennes 1, 1987. http://tel.archives-ouvertes.fr/tel-00675863.
Повний текст джерелаLe, Diagon Yann. "Déformations locales et structuration des charges dans les nanocomposites étirés." Paris 6, 2005. http://www.theses.fr/2005PA066323.
Повний текст джерелаTexier, Michaël. "Microstructures et mécanismes de déformation des alliages quasicristallins Al-Cu-Fe et Al-Pd-Mn déformés aux hautes et basses températures." Poitiers, 2004. http://www.theses.fr/2004POIT2268.
Повний текст джерелаAs well as their surprising structures, quasicrystalline alloys present peculiar physical properties. In particular, their mechanical properties combine very high hardness with extreme brittleness at low temperatures. Beyond 70 % of their melting temperature, they become ductile and their plastic behaviour shows a characteristic softening stage during the deformation test. These features suggest that the influence of diffusion processes on deformation mechanisms is significant and plays an important role during plastic deformation. In the course of this work, a study of the plastic behaviour of Al-Cu-Fe and Al-Pd-Mn alloys has been carried out. Various mechanical tests and TEM observations of deformed specimens were produced in order to identify the microscopic mechanisms that control the plasticity of icosahedral quasicrystalline alloys. Different microscopic mechanisms are proposed so as to explain the atypical mechanical behaviour of these alloys
Denneulin, Thibaud. "Holographie électronique en champ sombre : une technique fiable pour mesurer des déformations dans les dispositifs de la microélectronique." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00844107.
Повний текст джерелаCastelein, Gilles. "Etude par microscopie à force atomique de la morphologie de la surface de polymères semi-cristallins déformés : le polypropylène isotactique." Lille 1, 1996. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1996/50376-1996-417.pdf.
Повний текст джерелаLe treillis est inchangé après déformation à un taux de 0,5. Pour un taux de 1,0, les lamelles se fragmentent dans les directions d'allongement et de cisaillement appliqué. Ces structures accommodent la déformation par des mécanismes d'endommagement. La déformation des sphérolites bêta est plus facile. Les lamelles se fragmentent, sporadiquement dans la direction du cisaillement appliqué, de manière coopérative selon la direction d'allongement. Dans la direction de compression, elles sont soumises à des processus de pliage, coopératifs à taux élevé (1,0). L'interprétation des mécanismes est compliquée par trois paramètres : l'attaque acide effectuée pour révéler les morphologies, les hétérogénéités locales d'orientations lamellaires et la présence de deux formes sphérolitiques très différentes. Cette étude exploratoire montre la pertinence de la microscopie à force atomique en mode tapping pour l'observation de surfaces de matériaux polymères non modèles, jusqu'ici peu étudiés
Brien, Valérie. "Etude par microscopie électronique en transmission des mécanismes de déformation d'un superalliage à base de nickel en fatigue oligocyclique à haute température." Paris 11, 1995. https://tel.archives-ouvertes.fr/tel-02985973.
Повний текст джерелаIn order to understand the structural mechanisms of deformation in low cycle fatigued single-crystal superalloys, total deformation imposed with R epsilon = εmin / εmax= 0 or -1, according to crystallographic axis <001> tests were carried out tests at 950 °C (1223K), at the frequency 0. 25Hz. In R epsilon = 0 fatigue, we derive a general behaviour of the microstructures of deformation according to two parameters which are the total deformation imposed and the number of cycles. Thus, a simple tension causes the localization of dislocation networks at matrix/precipitated interfaces perpendicular to <001> so that excited dislocations are those that relax the parametric deviation. The greater the total deformation imposed or the greater the number of cycles, the more homogeneous the deformation spreads out to the vertical channels. Dislocations reduce the parametric misfit between the two phases. Type N coarsening is observed at 200 cycles for small amounts of total deformation imposed. In R epsilon = -1 fatigue, we show that compression deforms the vertical channels without the formation of networks since only one deformation glide sliding system is excited. Tension always deforms the horizontal channels in the same manner as in repeated fatigue. We also show that N type coarsening (identical to that obtained in tension creep for this type of superalloy) occurs very fast, as soon as 115 cycles. The synthesis of these results, enriched with considerations on the internal stresses (coherence stresses and stresses due to parametric deviation/misfit) allowed us to propose a model of behaviour that predicts (whether in fatigue R epsilon = 0, R epsilon = -1, in tension or compression) the nature and location of the active gliding systems as well as the qualitative distribution of the internal stresses of the superalloy
Willeman, Héloïse. "Multi-scale characterization of deformation mechanisms of poly-ether-ether-ketone (PEEK) under tensile stretching." Electronic Thesis or Diss., Lyon, INSA, 2023. http://www.theses.fr/2023ISAL0006.
Повний текст джерелаThe aim of this PhD work is accessing the microscopic deformation mechanisms of bulk poly-ether-ether-ketone (PEEK) under tensile stretching. Beforehand, the thermal and mechanical properties of two commercial grades of PEEK were characterized. Tensile specimens were then compression-molded to obtain morphologies as isotropic as possible and characterized below and above the glass transition temperature. Deformations at the scales of lamellar stacks and of the crystalline unit cell have been characterized by small and wide-angle X-ray scattering (SAXS and WAXS) performed in-situ during tensile tests. Simultaneously, the strain field within the samples was followed by digital image correlation (DIC) in order to compare microscopic and macroscopic strains. At both temperatures, lamellae tend to orient perpendicular to the tensile direction (TD). This orientation mechanism (which we denote as ‘Chain Network model’) is driven by the amorphous chains which transmit the stress between adjacent lamellae. The tensile strain in lamellar stacks perpendicular to TD is lower than the macroscopic tensile strain, which must be compensated by increased shear in inclined stacks. Some differences of behavior have been observed depending on the test temperature, especially at high deformation. A highly oriented morphology is ultimately obtained in all cases. However, the central scattering profiles changes with testing temperatures. Below Tg, the presence of small entities randomly oriented is indicated. Above Tg, the material is fibrillar and contains cavities
Dubois, Jean-Baptiste. "Conducteurs nanocomposites métalliques élaborés par déformation plastique sévère : formation et stabilité thermo-mécanique des nanostructures, propriétés induites." Poitiers, 2010. http://theses.univ-poitiers.fr/26782/2010-Dubois-Jean-Baptiste-These.pdf.
Повний текст джерелаThis thesis concerns the study of metallic nanocomposite copper/niobium (Cu/Nb) wires, combining high electrical conductivity and high strength, as required for the design of high magnetic field resistive coils. The reinforced continuous nanocomposite Cu/Nb conductors are fabricated via a severe plastic deformation process (SPD), which consists in repeated extrusion, drawing and bundling cycles (Accumulative Drawing and Bundling : ADB) and leads to the nanostructuration of the Nb reinforcements and a multi-scale Cu matrix. In order to optimize the process, the effect of heat treatments on texture and its development during the process were analysed by means of laboratory X-ray diffraction. Complementary in-situ heat treatments under synchrotron radiation gave a better insight into the elementary annealing mechanisms and enabled defining optimized heat treatments. These experiments also revealed that the thermal stability of Cu/Nb conductors is extremely dependent of the microstructure size: recovery, recrystallization, grain growth and all relaxation processes are frustrated in the case of nanocomposites. From these results, optimized “co-axial” conductors reinforced by Nb nanofilaments and nanotubes were processed. Their microstructure and physical properties have been characterized and compared to those of previous Cu/Nb nanocomposite conductors. With the possibility to produce long wires with improved properties, these new Cu/Nb nanocomposites offer a great alternative to existing conductors for future high magnetic field applications
Vultos, Winnie. "Influence de la microstructure sur les micromécanismes de déformation en fluage dans le superalliage AD730TM." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30166.
Повний текст джерелаThe study carried out during this thesis consists in analyzing the micromechanisms that control the creep deformation at 700 ° C, in the AD730(tm) superalloy developed by Aubert & Duval for the manufacture of turbine disks of the future turbojet engines for civil applications. The microstructure of the superalloy (size, distribution and chemical composition of the matrix and precipitates) has been characterized by conventional transmission electron microscopy (TEM) and by chemical analysis techniques (EDX and EELS spectroscopies). Deformation micromechanisms were identified at TEM after creep tests at 700°C at 500 MPa, 600 MPa and 850 MPa for different microstructural states. The study of the microstructures showed that thermal treatments can modify the local chemical composition of the different phases: variation of the Cr content in the matrix g, germination of g phase in the primary precipitates and variation of the Ti content in the secondary precipitates. These chemical fluctuations modify the antiphase boundary energy and the stacking fault energy that control the dislocation propagation. The quantification of these parameters allowed us to interpret the macroscopic behavior of the superalloy. Whatever the applied stress and the microstructural state, the observed intragranular deformation mechanisms correspond to conventional mechanisms reported in the literature for polycrystalline superalloys. Our results were validated by evaluating the stress levels associated with these mechanisms. The increase in the creep deformation rate at 700°C in the case of the fine-grained microstructure (in comparison with the coarse-grained microstructure), could be attributed to the primary precipitates where plasticity grows and is emitted. The increase of the creep strain rate at 850 MPa could be associated with the role of the grain boundaries which initiates the emission of several slip systems. In conclusion, this work allowed us to identify the parameters at microscopic scale that control the creep behavior at 700°C in the analyzed superalloy
Duchaussoy, Amandine. "Déformation intense d'alliages d'aluminium à durcissement structural : mécanismes de précipitation et comportement mécanique." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR135.
Повний текст джерелаThe combination of two mechanisms to increase mechanical strength, namely precipitation and grain size reduction, has been explored in this thesis in the aim of increasing the properties of age hardenable aluminum alloy from the 7### series.Manufacturing by severe plastic deformation makes it possible to obtain nanostructured alloys with high density of grain boundaries, which allows increasing the yield strength according to the Hall-Petch law. However, the high density of defects (dislocations, vacancies, grain boundaries ...) and the internal stresses generated by this deformation results in inherently unstable nanostructures when precipitation heat treatment is performed. These nanostructures experience rapid grain growth and drastic changes in precipitation mechanisms (heterogeneous precipitation, accelerated kinetics).In this work we have studied nanostructures obtained by severe plastic deformation using HPT and HPS (High pressure torsion / sliding) on a model alloy, Al-2% Fe and a commercial alloy AA7449 enriched with iron. The strategy was to stabilize the ultra-fine grain structure by intermetallic iron-rich nanoparticles (Zener pinning) to allow homogeneous precipitation hardening and thus combine the two mechanisms to increase the yield strength. In this context, we have particularly investigated: 1) the influence of solutes on the physical mechanisms leading to dynamic recrystallization nanostructuring; 2) specific mechanisms involved in co-deforming phases with very different mechanical behaviors; 3) the phase transformations that may lead either to the formation of a supersaturated solid solution or, on the contrary, to the decomposition of a solid solution by deformation-induced precipitation; 4) the relationship between the nanostructures thus generated, their thermal stability and related mechanical properties.The observation of the microstructures and understanding of the mechanisms induced by the deformation and relations with the mechanical behavior has been undertaken with many techniques: scanning and transmission electron microscopy (SEM/TEM), ASTAR (orientation mapping by TEM), and atom probe tomography. The study of precipitation was carried out by DSC (differential scanning calorimetry), SAXS (small angle X-ray scattering) and in-situ TEM. Finally, the relationship with the mechanical behavior has been established on the basis of tensile tests and micro-hardness measurements
Cabié, Martiane. "Mesures de contrainte dans les couches minces épitaxiées de semiconducteurs par la technique de la courbure adaptée à la microscopie électronique en transmission." Toulouse 3, 2005. http://www.theses.fr/2005TOU30217.
Повний текст джерелаLoubradou, Marc. "Etude des déformations autour des défauts cristallins à l'échelle atomique : dislocations, interfaces facettées." Grenoble INPG, 1990. http://www.theses.fr/1990INPG0155.
Повний текст джерелаGrosseau-Poussard, Jean-Luc. "Structures de films minces de MoSx déposés par techniques de faisceaux d'ions sur l'acier martensitique type Z100CD17 : corrélations entre propriétés tribologiques et microstructures de déformation." Poitiers, 1995. http://www.theses.fr/1995POIT2267.
Повний текст джерелаSauvage, Xavier. "Transformations de phases induites par déformation plastique intense. Cas des aciers perlitiques tréfilés et des nanocomposites filamentaires Cu/Nb." Rouen, 2001. http://www.theses.fr/2001ROUES032.
Повний текст джерелаBouscaud, Denis. "Développement de la microdiffraction Kossel pour l'analyse des déformations et contraintes à l'échelle du micromètrecristallins : applications à des matériaux cristallins." Paris, ENSAM, 2012. http://www.theses.fr/2012ENAM0012.
Повний текст джерелаX-ray diffraction is a non-destructive method frequently used in materials science to analyse the stress state at a macroscopic scale. Due to the growing complexity of new materials and their applications, it is necessary to know the strain and stress state at a lower scale. Thus, a Kossel microdiffraction experimental set-up was developed inside a scanning electron microscope. It allows to obtain the crystallographic orientation as well as the strains and stresses within a volume of a few cubic micrometers. Some experiments were also performed using a synchrotron radiation. An experimental procedure was developed to optimize the acquisition of Kossel line patterns and their post-processing. The stress calculation from Kossel patterns was validated by comparing the stress state of single crystals during in situ mechanical loading, obtained by Kossel microdiffraction and with classical diffraction methods. Then Kossel microdiffraction was applied to polycrystalline samples by gradually decreasing the grain size. Intergranular stress heterogeneities were for example measured in an interstitial-free steel. Experiments were finally carried out in thin layer samples representative of microelectronic components
Benhroma, Hadj-Aïssa. "Observation par microscopie électronique en transmission et par topographie aux rayons x des dislocations d'interface mobiles dans un bicristal sigma=9 de silicium." Vandoeuvre-les-Nancy, INPL, 1992. http://www.theses.fr/1992INPL003N.
Повний текст джерелаHüe, Florian. "Mesures de déformations dans des dispositifs de la microélectronique par microscopie électronique en transmission en haute résolution et holographie en champ sombre." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/325/.
Повний текст джерелаStrained silicon is now an integral feature of microelectronic devices due to the associated enhancement in carrier mobility. The general aim of this thesis is to explore how transmission electron microscopy can be used to measure strain in such systems. We show in particular how Geometric Phase Analysis (GPA) of High Resolution Electron Microscopy images (HREM) can be used to study thin layers of strained silicon grown upon virtual substrates of Si1-xGex. By studying different virtual substrate compositions and different layer thicknesses we have optimized the technique and evaluated its accuracy and reliability. Accuracy in strain measurement can reach 0. 2% for fields of view of 200 nm x 200 nm. The detailed comparison of experimental measurements and finite element simulations allows the quantification of thin foil relaxation for TEM lamellas. We show, for the first time, that strain can be mapped in two dimensions in an actual device, a p-MOSFET, with a spatial resolution of 2 nm. The second part concerns a new method developed in the CEMES-CNRS laboratory: dark-field holography. With the aid of a field emission gun and a biprism, interferometric fringes are created between a diffracted wave coming from a perfect crystal and a diffracted wave coming from a distorted area. Analysis of the hologram allows us to determine strain. Very large field of view (500 nm by 2 µm) can be obtained with an even better precision than HREM: 0. 02%. Finally, the complementarity of the two techniques is demonstrated through the study of various systems such as multichannel, uniaxial compressed p-MOSFETs (SiGe) with different channel lengths or uniaxial tensile strained n-MOSFETs (Si:C)
Moulard, Raphaël. "DÉVELOPPEMENT ET MISE EN OEUVRE D'UNE MÉTHODE DE MESURE DE CHAMPS DE DÉFORMATION À L'ÉCHELLE MICROMÉTRIQUE." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2007. http://tel.archives-ouvertes.fr/tel-00351685.
Повний текст джерелаBerger, Jean François. "Approche microscopique auto-consistante des processus nucléaires collectifs de grande amplitude à basse énergie : application à la diffusion d'ions lourds et à la fission." Paris 11, 1985. http://www.theses.fr/1985PA112268.
Повний текст джерелаA theoretical framework and numerical techniques allowing to describe low energy, large amplitude collective phenomena in nuclei from the only data of the nuclear effective interaction is presented. In this method, the collective properties of the system are analyzed with the help of the full Hartree-Fock-Bogolyubov theory and different kinds of constraints acting as external fields. The collective dynamics is then deduced from the self-consistent approach in a completely quantum-mechanical formalism based on the Generator Coordinate prescription and the adiabatic approximation. With this procedure, nuclear structure effects, in particular the influence of pairing correlations on the collective dynamics, are incorporated in a completely microscopic and self-constent way. The applications we present use GOGNY’S D1 effective interaction. Due to the very general parametrization of this force – in particular, its finite range – most known nuclear properties, including those associated to pairing, can be reproduced quantitatively. The ¹²C + ¹²C reaction at low energy is first studied. The position of the two first 0⁺ resonances is consistent with experimental data. The analysis of the wave functions shows that these resonances do not arise from a quasi-molecular ¹²C - ¹²C state. Our approach is then applied to the fission of ²⁴⁰Pu. Potential energy surfaces as functions of elongation, left-right asymmetry and necking-in are displayed. The main known characteristics of these surfaces, in particular fission barrier heights appear to be correctly reproduced. An interpretation for the mechanism of scission and for cold fission events is proposed. A dynamical calculation taking into account the variations of the collective inertia confirms this interpretation and shows that the nuclear evolution between saddle and scissions can be described using the adiabatic approximation
Moulart, Raphaël. "Développement et mise en oeuvre d'une méthode de mesure de champs de déformation à l'échelle micrométrique." Phd thesis, Paris, ENSAM, 2007. http://pastel.archives-ouvertes.fr/pastel-00003212.
Повний текст джерелаAmiguet, Élodie. "Déformation expérimentale de diopside dans les conditions de pression et température du manteau supérieur." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10001/document.
Повний текст джерелаThe plasticity of mineraIs under Earth's upper mantle conditions plays a major role in the processes that affect the dynamics of the Earth's interior. The properties of mantle mineraIs are still not weIl constrained. The purpose of this work is to study the deformation of clinopyroxenes (taking diopside as a proxy) under pressure since they are a major constituent of the upper mantle. Oriented single-crystals as weIl as polycristals of diopside were deformed under upper mantle pressures and temperatures. Deformation experiments have been conducted using a D-DIA multi-anvil press coupled with synchrotron radiation in order to perform in situ stress and strain measurements. The microstructures of deformed samples were characterized by Transmission Electron Microscopy. Mechanical data have enabled us to determine the high-pressure rheological law for 1/2 <110>{110} glide systems. At high pressure and temperatures, 1/2 <110> and [001] slips are dominant while [100] and [010] slips remain the hardest slip systems. VPSC modeIling based on our experimental results agree weIl with the textures observed in our experimentaIly deformed polycrystals as weIl as those in naturaIly deformed samples. We conclude that clinopyroxenes tend to reduce the upper mantle seismic anisotropy
Bethoux, Jean-Marc. "Relaxation des contraintes dans les hétérostructures épaisses (Al,Ga)N : une piste originale pour la réalisation de diodes électroluminescentes à cavité résonante." Nice, 2004. http://www.theses.fr/2004NICE4042.
Повний текст джерелаIn [0001]-oriented III-nitrides, the glide of threading dislocations is inefficient to relax the misfit stress. When films are grown under tensile stress, the plastic relaxation occurs through the film cracking and the introduction of misfit dislocations from the crack edges. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been used in order to characterize cracked (Al,Ga)N/GaN heterostructures. A cooperative mechanism between cracking and ductile relaxation has been outlined. The relaxation rate strongly depends in the (Al,Ga)N/GaN film thickness. By combining the lateral growth of (Al,Ga)N and the stress relaxation, craks have been healed and high quality (Al,Ga)N films have been grown by metal-organic vapour phase epitaxy (MOVPE). Coherent growth of (Al,Ga)N/GaN Bragg mirrors has been carried out of those thick relaxed (Al,Ga)N films. Their optical and electrical properties as well as their stress have been investigated. A resistivity measurement method has been developed to comply with the planar technology. Resonant cavity light emitting diodes (RCLED° have been realized to demonstrate the benefit of this new (Al,Ga)N growth method
Nzogang, Billy Clitton. "Caractérisation avancée de la plasticité des minéraux par microscopie électronique en transmission." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R085.
Повний текст джерелаThe internal activity of our planet is manifested on the surface by geological phenomena such as volcanism or earthquakes. This activity results from mantle convection, which aims to transport the internal heat of the Earth to the surface. These vast convective movements involve in deep the flow of rocks in the solid state. Understanding the basic mechanisms that allow rocks and their minerals to undergo these large deformations is a major issue in geophysics. The Transmission Electron Microscope (TEM) is traditionally used for studying the mechanisms of plasticity of minerals. However, new techniques based on scanning electron microscopy now make it possible to visualize preferential orientations as well as intracrystalline disorientations. The ACOM-TEM (Automated Crystal Orientation Mapping in Transmission Electron Microscopy) device makes it possible to produce crystal orientation maps at the TEM scale. In this thesis, we explore the possibilities of this technique applied to the deformation of minerals. In particular, we show that the ACOM-TEM technique can be applied to samples sensitive to electron irradiation such as quartz or high pressure phases. The use of high resolution mapping provides an alternative to conventional diffraction contrast imaging, applicable to sensitive minerals. We also show the robustness of the ACOM-TEM technique with respect to samples containing high dislocation densities, which makes it an attractive technique for the study of highly deformed materials as in the case of deformation experiments under high pressures. We also present some applications to the study of recovery and recrystallization phenomena
Morán, Meza José Antonio. "Propriétés structurelles et électroniques du graphène sur SiC(0001) étudiées par microscopie combinée STM/AFM." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00961600.
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