Dissertations / Theses on the topic 'Texture de recristallisation'
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Zhu, Kangying. "Etude des mécanismes de déformation et de recristallisation dans un alliage de zirconium." Paris 13, 2006. http://www.theses.fr/2006PA132021.
Piekos, Kristian. "Modéllisation de la recristallisation dans les métaux : prévision des cinétiques et des évolutions des texture et de microstructure." Paris 13, 2006. http://www.theses.fr/2006PA132011.
Bertrand, Drira Chloé. "Optimisation de la texture de catalyseurs zéolithiques pour l'oligomérisation des oléfines." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2014. http://www.theses.fr/2014ENCM0002/document.
Recently the demand in diesel has been exceeding the production of European refineries and, inversely for gasoline. The objective of this thesis is to increase the value of the gasoline excess and meet the demand in diesel using the olefin oligomerization process. We focused on the oligomerization of pentene, which can transform into heavier molecules from 10 to 25/30 carbon atoms in contact with a solid acid catalyst . We chose zeolites as catalysts and more specifically mordenite. To improve the molecular transport to the active sites we have modified the mordenite texture by creating a secondary mesoporous framework inside the crystals, using two different post-synthesis treatments: desilication and recrystallization. Desilication treatment generates intra and inter-crystalline mesopores (from 10 nm to 100 nm diameter) by partial dissolution of the zeolite in the presence of a basic solution. Recrystallization creates a well-organized mesoporosity with a uniform diameter (small mesopores of 4 nm) due to the use of an organic template of mesopores under hydrothermal conditions. Starting from the same parent mordenite we obtained micro-mesoporous mordenites with different textures, porosity and acidity properties depending on the treatment. Finally, after the development of the experimental pilot, we compared the performance (conversion, stability, selectivity, yield in oligomers C15-C20+, branching degree of the products) of our optimized catalysts of micro-mesoporous mordenite with some reference catalysts in order to establish relations between structure-acidity and catalytic performance. We highlighted the positive impact of the introduction of mesopores in the catalyst on the conversion, stability and yield in oligomers C15-C20+. A methodology to characterize the branching degree of the products has also been developed for completing the analysis of catalytic performances
Hary, Benjamin. "Compréhension et modélisation de l'influence du taux de renforts et de la texture de déformation sur la recristallisation des aciers ODS ferritiques." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS339/document.
Oxide dispersion strengthened steels are considered as cladding materials for Sodium Fast Reactor. Due to the nano-precipitates incorporated within the microstructure, their mechanical properties are very high, especially under creep loading. Moreover, the ferritic-martensitic lattice gives ODS steels a remarkable swelling resistance under radiation. The manufacturing route of ferritic ODS steels is complex and induces a strong morphologic and crystallographic texture. The microstructure needs to be recrystallized but this recrystallization is often heterogeneous and difficult to control. In this framework, this investigation aims at achieving a better understanding of the recrystallization mechanisms in ODS steels that strongly rely both on the nano-oxydes concentration and the applied deformation. Thereby, several model grades with various concentrations of oxydes were elaborated and characterized at different scales (EBSD, SANS, DSC). It appears that the chemical composition of the nano-oxydes strongly influence the microstructure stability and its ability to recover after consolidation. Throughout this study, the strong relationship between the cold-deformation path, the stored energy distribution and the recrystallized microstructure has been highlighted. When the thermo-mechanical treatment is optimal, homogeneous recrystallized microstructures weakly textured can be achieved. Experiments also showed that decreasing the nano-oxydes concentration does not clearly favor recrystallization. Monte Carlo modelling was performed to simulate grain growth and recrystallization in the presence of second phase particles and the simulations helped to identify the mechanisms that occur experimentally. Furthermore, the tensile properties of different metallurgical states were investigated and it came out that the recrystallization notably increases the ductility at high temperature without significantly affecting the yield strength. The results obtained on model materials allowed to achieve a better understanding of the mechanisms implied in the recrystallization process of ODS steels. Several possible optimizations to the current manufacturing route are discussed from the conclusions of this study
Yazidi, Samir. "Influence du caractère de spécialité des joints de grains sur la texture granulaire et la texture de joints dans l'oxyde de nickel." Paris 11, 1988. http://www.theses.fr/1988PA112155.
The purpose of this study is to verity whether the intrinsic properties of special and general grain boundaries (GB) may influence such characteristics as grain texture and grain boundary texture, during grain growth process in a polycristalline material. Three parameters are of importance: -average grain diameter which is an indicator of the residual driving force responsible for grain growth; -average grain growth rate, since GB mobility is a discriminative factor for special and general GB behavior and is a function of impurity conten; -specialness character Of the GB's which allows their classification. In order to examine the influence of the first two parameters, about 250 GB's belonging to several samples prepared by oxidation of nickel in various conditions, were characterized. The data which were obtained up to now do not seem to indicate that the specialness character of the, grain boundaries influences significantly grain texture or GB texture. This conclusion can be explained by topological requirements relative to a polycrystal tree of external stresses
Dewobroto, Natanael. "Etude de l'évolution de texture lors de la recristallisation et de la croissance de grains d'alliages de titane et de zirconium." Metz, 2004. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2004/Dewobroto.Natanael.SMZ0412.pdf.
The objective is to explain mechanisms leading to texture change during annealing for commercially pure Ti (T40) and a zirconium alloy (Zr702) by making relationships between phenomena occurred during deformation, recrystallization and grain growth. In this experimental study, X-Ray goniometry SEM-EBSD and TEM were used to give complete descriptions on microstructure and texture evolution from deformed state until grain growth stage. Texture evolution for both materials are similar during cold rolling and annealing. Texture changes mainly during grain growth. Recrystallization changes slightly the rolling texture (maxima at {Phi1=0° PHI Phi2=0°}. Different deformation behaviors of both materials during cold rolling give differences in recrystallization mechanisms. T40 and Zr702 showed a not oriented nucleation. The slight growth selection since recrystallization stage develops the texture component {Phi1=0° PHI Phi2=30°} which becomes main component at advanced stage of grain growth. T40 evolves by normal grain growth for annealing temperature at 600, 700 and 800°C. Grain growth kinetics parameters for T40 were determined. Zr702 showed lower grain growth kinetics due to precipitates which are also the responsible for abnormal grain growth when heat treatments were done for long time at 800°C
Mavrikakis, Nikolaos. "Effect of nano-segregation of tin on recrystallisation and grain growth in automotive steels." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0545.
This Ph.D. thesis investigates the effect of Sn solute segregation on the formation of recrystallisation texture in ferritic alloys. Both electron back-scatter diffraction and atom probe tomography were used to investigate the texture development and the local solute segregation respectively. In-situ electron back-scatter diffraction reveals that the strain heterogeneity in the deformed microstructure is a crucial factor for subsequent annealing, especially in the solute added alloys. Solute was found to have a profound effect on the annealing texture. Mainly, Sn was shown to affect the annealing phenomena via solute-dislocation interaction and grain boundary segregation. Direct observations with atom probe tomography reveal and quantify the levels of segregation at grain boundaries during the development of the recrystallised microstructure. The role of segregation at each stage of recrystallisation is discussed and a strong effect at the recrystallisation nucleation stage is suggested. Atom probe tomography results in combination with atomistic modelling of equilibrium segregation, concluded that the segregation depends on the misorientation. Nonetheless, the solute segregation in high-angle grain boundaries was found to be independent of their geometric characteristics (i.e. general, special grain boundaries). Finally, texture development could be explained in terms of the oriented nucleation theory of recrystallisation, while the presence of some mobile interfaces may subsequently also contribute in the oriented growth of some recrystallised grains
HENRY, JEAN. "Influence de l'etat de precipitation sur la formation de la texture de recristallisation dans un acier sans interstitiel microallie au niobium." Paris 11, 1995. http://www.theses.fr/1995PA112139.
Dewobroto, Natanael Wagner Francis. "Etude de l'évolution de texture lors de la recristallisation et de la croissance de grains d'alliages de titane et de zirconium." Metz : Université Metz, 2008. ftp://ftp.scd.univ-metz.fr/pub/Theses/2004/Dewobroto.Natanael.SMZ0412.pdf.
Chhann, Sorphal. "Etude de la recristallisation de l'Invar (alliage Fe-36%Ni) déformé par laminage asymétrique." Paris 11, 2007. http://www.theses.fr/2007PA112105.
Ln this study, we are interested in the development of recrystallized texture of invar deformed by asymmetrical rolling. The texture and the microstructure have been characterized at different scales using XXray and neutron diffraction, Scanning Electron Microscopy (SEM) associated with Electron Back Scattered Diffraction (EBSD) and Transmission Electron Microscopy (TEM). The deformed microstructure consists of elongated bands with a dislocation network substructure. There is not any cellular substructure. Concerning the texture, classical rolling components are obtained. However, in the case of the one-way asymmetrical rolling, the texture is Iightly turned around the transverse direction. After annealing, the recrystallized grains are more or less equiaxe, and the texture contained a large fraction of the cubic component associated with its twin. For the same thickness reduction, the acuity of the cubic component is larger after asymmetrical rolling than after symmetrical rolling. Concerning the microstructure evolution during annealing, we have observed the evolution of the dislocation networks into cellular substructures. Recovery is faster in the grains with the éubic orientation. As a consequence, the difference in stored energy between grains with the cubic orientation and the other orientation increases and explain the nucleation b Strain Induced Bounda Mi ration SIBM mechanism
Qiang, Fengming. "Microstructure and texture evolution of high-temperature α phase in TiAl alloy during thermomechanical processing." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0166.
Increasing demands on modern turbines require (α2+γ) lamellar-structured TiAl alloys with fine colony size and properly aligned lamellae. According to the α → α2+γ phase transformation, the lamellar structure depends directly on the high-temperature α phase. Thus, the lamellar structure optimization could be realized by the modification of high-temperature α phase through thermomechanical processing. In this work, a thorough investigation was conducted on the high-temperature α phase in two TiAl alloys in terms of the deformation behavior, dynamic recrystallization (DRX), grain growth and texture evolution.Under uniaxial compression, the DRX of the α phase is a continuous fragmentation process (CDRX) in three characteristic stages: ⅰ) serrations of grain boundary and formation of symmetrical-tilt boundaries with <0001> disorientation axis near boundary bulging regions; ⅱ) formation of subgrains by evolving symmetrical-tilt boundaries into asymmetrical-tilt boundaries with <10-1x> disorientation axis by absorbing basal dislocations, or tilt-twist boundaries with <11-2y> disorientation axis by rotational movements of the bulged parts; ⅲ) detachment of subgrains from the parent grain with gradually increased misorientation, and mixture with the ones fragmented from other grains by grain boundary sliding. These three processes happened repeatedly from grain boundary regions toward grain interiors until the whole initial microstructure was replaced by the DRXed one. The plastic deformation of the α phase is closely related to the crystallographic orientations of the initial α grains that play an important role in the deformation mechanism and the CDRX progress (softening). For the soft α grains, CDRX was completed quickly at a relatively small macroscopic strain by intragranular dislocation slip. The hard α grains demonstrated two ways: ⅰ) grains with <0001>//LD, in which dislocation accumulation was only assisted by the local strain accommodation with the neighboring α grains from boundary regions; ⅱ) grains with <11-20>//LD, in which dislocation accumulation was achieved by kinking through basal slip and dislocation slip in the boundary regions from incompatible local strain. These grains required large strain to accumulate sufficient dislocations for CDRX. The strain-resolved contribution of the deformation (hardening) and CDRX (softening) result in the specific flow stress states. The texture evolution is mainly induced by dislocation slip. The orientations of the DRXed grains were largely inherited from those of the parents. With the deformation, the tilted basal fiber typed orientations developed in both the retained coarse α and the formed DRXed α grains. The hot compression produces refined α grains but not expected texture to align (α2+γ) lamellae. The microstructure and texture of the α phase during hot extrusion in the (α+β) phase region exhibit different features. The extruded microstructure was very heterogenous, comprising a large population of unRXed α grains and fine primary RXed α grains with <10-10>//ED and a small population of grown α grains with <11-20>//ED. The two texture components are beneficial for lamella alignment. Besides, the thermally-induced α → β phase transformation interweaving with the abnormal α grain growth happened during the transition from extrusion to water-quenching, producing two types of β particles: i) intergranular β particles with the Burger OR with their neighboring α grain; ii) intragranular β particles without the OR with the hosts from the intergranular β ones after being swallowed by the abnormally grown α grains
Miszczyk, Magdalena Maria. "Microstructure and texture evolution during annealing of plane strain compressed fcc metals." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-00904405.
Ateba, Betanda Yanick Blaise Olivier. "Formation de la l'hypertexture Cube {100}<001> dans les alliages cubiques à faces centrées." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS001.
Substrate tapes were prepared by cold rolling and annealing of a Fe48%Ni and Ni5%W alloys in order to obtain Sharp Cube {100}<001> oriented substrate for photovoltaic thin films and superconductor cables in particular.The effect of microalloying elements sulfur and niobium on recrystallization and sharp Cube formation was studied in Fe48%Ni. It was shown that the addition of sulfur promotes the formation of Cube grains while the addition of niobium prevents the Cube grains formation. Regarding sulfur, it combines with manganese to form the MnS precipitates wich increases the stored energy difference between Cube component and others cold rolled components ECube/other when sulfur is added. This stored energy difference explains the sharpness of the Cube texture when sulfur is added. On the contrary the niobium microalloying element addition prevents the formation of Cube grains. This could be explained by the fact that stored energy of cold-rolled components decreases with the addition of niobium and thus decreases Cube grains fraction when niobium is added. In order to explain these results, the development of Cube texture during recrystallization has been investigated in detail by EBSD, furthermore, the effect of stored energy has been studied by carrying out neutron diffraction measurements on the deformed states
Monnet, Ghiath. "Caractérisation de l'énergie stockée par diffraction des rayons X dans les multicristaux de cuivre : effet sur la recristallisation statique." Phd thesis, Université Paris-Nord - Paris XIII, 1999. http://tel.archives-ouvertes.fr/tel-00426731.
Mavrikakis, Nikolaos. "Effect of nano-segregation of tin on recrystallisation and grain growth in automotive steels." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0545.
This Ph.D. thesis investigates the effect of Sn solute segregation on the formation of recrystallisation texture in ferritic alloys. Both electron back-scatter diffraction and atom probe tomography were used to investigate the texture development and the local solute segregation respectively. In-situ electron back-scatter diffraction reveals that the strain heterogeneity in the deformed microstructure is a crucial factor for subsequent annealing, especially in the solute added alloys. Solute was found to have a profound effect on the annealing texture. Mainly, Sn was shown to affect the annealing phenomena via solute-dislocation interaction and grain boundary segregation. Direct observations with atom probe tomography reveal and quantify the levels of segregation at grain boundaries during the development of the recrystallised microstructure. The role of segregation at each stage of recrystallisation is discussed and a strong effect at the recrystallisation nucleation stage is suggested. Atom probe tomography results in combination with atomistic modelling of equilibrium segregation, concluded that the segregation depends on the misorientation. Nonetheless, the solute segregation in high-angle grain boundaries was found to be independent of their geometric characteristics (i.e. general, special grain boundaries). Finally, texture development could be explained in terms of the oriented nucleation theory of recrystallisation, while the presence of some mobile interfaces may subsequently also contribute in the oriented growth of some recrystallised grains
Theyssier, Marie-Christine. "Compression plane à chaud de cristaux d'aluminium et d'aluminium-magnésium : de la déformation à chaud à la recristallisation." Grenoble INPG, 1996. http://www.theses.fr/1996INPG4209.
Vigna, Gustavo. "Application des techniques de canalisation d'électrons et de Kossel à l'étude de la texture locale et des contraintes internes de tôles de fer à 3% de silicium." Paris 11, 1987. http://www.theses.fr/1987PA112052.
Two local techniques of crystalline analysis, the Selected Area Electron Channeling Patterns and the Kossel patterns ln reflexion have been applled : 1 - to the study of the local texture evolution during secondary recrystallisation of Fe 3%SI sheets and of the characteristics of grain boundaries surrounding a (110> (0011 grain. 2 - to the determination of residual stresses of these same sheets. Lt has been pointed out that a Goss grain has a tendency to consume more quickly grains which are near a coincidence relationship. The migration velocity of special grain boundaries is higher than the one of general grain boundaries, however it tends to become uniform when temperature increases. It has also been shown that the Goss grain consume preferentially grains belonging to the main component (111) <112> of the prlmary recrystallization texture relative to the minor component (100) <012>. On an other hand we have tried to evaluate with the help of the Kossel technique residual stresses of Fe 3%SI sheets strained after secondary recrystallization. It has been pointed out that our experimental device does not allow to determine with sufficient accuracy neither the distance film-source nor the localisation of the center of the pattern which are necessary for the residual stresses determination
Chovet, Sauvage Corinne. "Evolution des microstructures et des textures en grande déformation à chaud d'un alliage Al-Mg-Si : caractérisation du mécanisme de recristallisation dynamique continue." Grenoble INPG, 2000. http://www.theses.fr/2000INPG4210.
Bouchara, Daniel. "Elaboration, microstructure et proprietes magnetiques d'alliages de fer a six et demi pour cent de silicium elabores par solidification rapide." Toulouse, INSA, 1990. http://www.theses.fr/1990ISAT0025.
Shi, Hailong. "Recrystallization of 2D dimensioned Copper (Cu) foils and graphene nanosheets (GNSs) reinforced Cu matrix laminated composites." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0096.
Recrystallization is the intrinsic process of cold-deformed metallic materials that occurs inevitably during the thermal treatment. The produced recrystallization texture contributes to the anisotropy of the mechanical and physical properties. Motivated by the minimization of modern products, 2D materials and laminated composites are increasingly demanded by many applications. Thus, for both scientific and engineering purposes, investigations on the recrystallization of such materials are needed to understand the underlying mechanisms. In this work, Cu foils and graphene nanosheets (GNSs) reinforced Cu matrix laminated composites with Cu foil thicknesses of 10 μm and 30 μm were fabricated, and the recrystallization features were thoroughly investigated from microscale to macroscale by means of SEM-EBSD for microstructure observation, neutron and synchrotron radiation for texture analysis and in-situ synchrotron radiation for lattice strain evaluation. The obtained data were analyzed in the frame of crystallography combined with crystal elasticity and surface energy. The results showed that the recrystallization behavior of the Cu foils were greatly affected by the Cu foil thickness and the addition of the GNSs. For the 10 μm thick Cu foils without GNS, they underwent a transition from the cold-rolling texture to a recrystallization texture dominated by RD-rotated Cube and φ_2-rotated Copper components. The transition was screened by both intrinsic microstructural and extrinsic sample geometrical factors. The orientations of the nuclei were mainly inherited from the deformation orientations. Those with low Taylor factors (Cube, Goss and Brass) demonstrated size preference. The post-nucleation growth was affected by the biaxial thermal elastic constraint and surface energy. Due to their opposite effects, the orientations having moderate biaxial moduli and surface energy density (S, Copper, Brass and recrystallization components) survived, resulting in a mixed texture at the completion of recrystallization. The coherent Σ3 boundaries between the new components stabilized their growth through consuming the other oriented crystals separated by random high-angle boundaries. When sintered into bulk, the texture of the Cu was dominated by the orientations of the abnormally grown grains. The effects of GNSs on the recrystallization of Cu foils were also Cu foil thickness dependent. For the 10 μm thick foils, the effect of the GNSs manifested after the samples were sintered to high temperatures (> 700 ℃). Instead of creating much constraint to the expansion of the adjacent Cu foils, the GNSs worked as a barrier preventing the penetration of the grown Cu grains, resulting in the stabilization of the recrystallization texture represented by the two rotated components. For the Cu/GNS composite with Cu foil thickness of 30 μm, the results evidenced that a strong Cube orientation was produced in the Cu/GNS composite instead of the individual non-Cube orientations in the pure Cu stack without GNSs. Detailed strain-state analysis of the Cu foils in the Cu/GNS composite revealed that the anisotropic expansion behavior of the GNS that is incompatible with that of the Cu foils imposed multiple elastic constraints to the foils, resulting in a biaxial isostrain state in the surface layers and a uniaxial compressive strain state in the central layer. The elastic anisotropy of Cu favors the growth of the Cube oriented grains to minimize the total strain energy. The results of the present work provide quantitative and detailed information on recrystallization of thin Cu foils and laminated composite, which contributes to deepening the understanding of recrystallization behaviour of 2D materials. The mechanisms revealed are useful for analysing abnormal grain growth in elastically strained materials and can also be applied to fabrication process for texturization or even monocrystallization
Talowski, Catherine. "Contribution à l'amélioration des tôles magnétiques non orientées utilisées en électrotechnique." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0105.
Bayona-Carrillo, Nicolás. "Relation procédé-microstructure-propriétés de tubes sans soudure de Ti–3Al–2,5V laminés à pas de pèlerin." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0423.
Cold pilgered Ti-3Al-2.5V alloy tubes are used in a stress relieved condition in commercial and military aircraft since the late 20th century. Despite the extensive use of these tubes, some aspects of the relations between processing and properties are still misunderstood, restricting the possibilities for the development of new products. The key properties are the tensile yield stress and elongation, the Contractile Strain Ratio (CSR) and the fatigue resistance. While early studies have shown how the pilgering process impacts texture and some of the effects of texture on these properties, public literature dismisses the effects of recovery and recrystallization, which both occur during the various annealing treatments of the transformation schedule. To fill this gap, this work focuses on the fine characterization of the local microstructures and textures of tubes produced in industrial trials. EBSD maps presented in this work show that the stress relieving treatment produces discontinuous recrystallization with variable local kinetics depending on the heterogeneity of the deformed condition, which is caused by the high anisotropy of the hexagonal alpha phase. The recrystallized fraction Rx is shown to influence the tensile deformation behavior, as anomalous yield point phenomena are more pronounced when Rx increases. Under the studied conditions, strong recrystallization is shown to produce fine equiaxe grains and a weak texture although without significant modification of the deformation texture components. This result suggests that grain growth is inhibited by the beta phase present in the microstructure. This work also analyses the influence of the sequences of deformation and recrystallization on the final texture and microstructure. It was confirmed that texture can be modified by the ratio of thickness to diameter reduction and that texture determines the CSR. The latter result is well reproduced in crystal plasticity simulations. The microstructural analysis of a wide range of tube dimensions suggested that the sizes of recrystallized grains in the final microstructures can be tailored through the choice of the overall strain path. Finally, the fatigue behavior of tubes with similar microstructure and different texture were studied under internal pulsed pressure tests. The results suggest that tangentially textured tubes are more tolerant to surface damages and crack propagation at high and medium stress amplitudes. The radial textures, however, improve the endurance limit under the conditions of these trials
Wauthier, Aurélie. "Observation expérimentale et prévision des paramètres de la déformation déterminants pour la genèse des textures cristallographiques lors de la recristallisation des tôles minces d'aciers à basse teneur en carbone." Phd thesis, Université Paris-Nord - Paris XIII, 2008. http://tel.archives-ouvertes.fr/tel-00915754.
Brochet, Stéphanie. "Compréhension du rôle de la microstructure d'aciers inoxydables austénitiques à grains fins sur le comportement en fatigue." Lille 1, 2007. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2007/50376-2007-187.pdf.
Liu, Xiaorui. "Crystallographic and microstructural study of as-cast and heat-treated Srmodified Al-12.7Si alloys." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0103/document.
Al-Si alloys have attracted considerable attention due to their importance to industrial applications. In the present work, both crucible slowly solidified and slowly directionally solidified (DS) high-purity Al-12.7 wt. % Si alloys with and without 400 ppm Sr addition have been prepared and heat treated. The influence of Sr addition and post heat treatments on the microstructural and crystallographic features of the eutectic phases has been systematically studied. The growth characteristics of eutectic Si in the unmodified and the Sr-modified Al-12.7Si alloys were investigated. For the non-modification case, the formation of repeated single-orientation twin variants enables rapid growth of eutectic Si according to the twin plane re-entrant (TPRE) mechanism. Microscopically, Si crystals are plate-like elongated in one <1 1 0> direction that is not in accordance with the <1 1 2> growth assumed by the TPRE model. The <1 1 0> extension is realized by paired <1 1 2> zigzag growth on parallel twinning planes, leading to alternative disappearance and creation of 141° re-entrants. This growth manner ensures Si crystals to expose only their low-energy {1 1 1} planes to the melt. For the Sr-modification case, substantial changes appear in eutectic Si morphology, attributable to the restricted TPRE growth and the impurity induced twinning (IIT) growth. The first enhances lateral growth by forming new twins with parallel twinning planes, while the second leads to isotropic growth by forming differently oriented twins. Heat treatment brings about refinement of both eutectic phases. The refinement of the α-Al occurs concomitantly with the fragmentation and spheroidization of Si and is mainly related to the fracture of the Si crystals due to their limited capacity to accommodate the giant thermal expansion of the α-Al and the diffusion of Al atoms to the cracks during the heat treatment. The Si fracture generates “capillarity” force that activates the diffusion of Al atoms to the gap of the crack. Due to the substitutional feature of Al diffusion, the migration of vacancies toward the interior of the α-Al is induced when Al moves to the gaps, thus the voids of the Si fracture are transferred to the α-Al. In this way, the crystals of α-Al are distorted and defected. The produced crystal defects, in turn, initiate recovery and even recrystallization of the α-Al, resulting in grain refinement. The α-Al phase in the directionally solidified Al-12.7Si-0.04Sr alloy, displays a strong <1 0 0> fiber texture in the solidification direction. Giant <1 0 0> α-Al grains are mainly formed in the outer circle region of the cylindrical specimen due to the favorable heat evacuation directions available for the three <1 0 0> directions. After heat treatment, the texture intensity of the α-Al phase decreases due to the recovery and recrystallization, but the texture type does not change. For the eutectic Si phase in the as-cast alloy, there are two main fiber texture components, <1 0 0> and <1 1 0> in the DS direction, accompanied by two weak components, <2 2 1> and <1 1 3> in the same direction. The <1 0 0> and <1 1 0> components are from Si crystals located in the outer circle and center regions of the cylindrical specimen. The <2 2 1> and the <1 1 3> components are from multiple twins of the <1 1 0> and <1 0 0> oriented crystals. The weak intensities of these two components are related to their minor volume fraction. Once heat treated, the twinned parts with minor volume fractions enlarge at the expense of their twin related matrix, thus the <1 1 0> component is weakened and accompanied by the intensification of the components from the twins. The disappearance of the <1 1 3> component and the appearance of the <1 1 5> component are due to crystallographic rotation of Si crystals during their fragmentation
Busch, Lauper Karin. "Restauration, recristallisation et textures de fils minces métalliques en cuivre et or /." [S.l.] : [s.n.], 1988. http://library.epfl.ch/theses/?nr=736.
Rouag, Nadjet. "Influence de la texture cristallographique et de la spécialité des joints de grains sur l'anisotropie de migration des joints entourant un grain d'orientation (110)<001> au cours des premiers stades de la recristallisation secondaire dans les toles de Fe-3% SI en présence de précipités AIN et MnS." Paris 11, 1988. http://www.theses.fr/1988PA112364.
Maurice, Claire. "Textures de compression plane à chaud d'alliages d'aluminium : expériences et simulations." Grenoble INPG, 1994. http://www.theses.fr/1994INPG4208.
Castelnau, Olivier. "Modélisation du comportement mécanique de la glace polycristalline par une approche auto-cohérente : application au développement de textures dans les glaces des calottes polaires." Phd thesis, Université Joseph Fourier (Grenoble), 1996. http://tel.archives-ouvertes.fr/tel-00748169.
LA, CHAPELLE SOPHIE de. "Recristallisation d'un alliage Al-Mg-Si : développement des textures et effet de la précipitation." Grenoble INPG, 2000. http://www.theses.fr/2000INPG4209.
Cheneau-Späth, Nadine. "Comportement de monocristaux et de polycristaux de métaux hexagonaux en grandes déformations plastiques : compression plane du titane et du magnésium." Grenoble INPG, 1996. http://www.theses.fr/1996INPG4201.
PAILLARD, PASCAL. "Caracterisation et simulation des textures de recristallisation d'alliages fer 3% de silicium obtenus par coulee directe en bandes minces." Paris 11, 1994. http://www.theses.fr/1994PA112074.
MIROUX, ALEXIS. "Etude experimentale et modelisation des mecanismes de formation des textures de recristallisation dans les aciers sans interstitiels stabilises au titane." Paris 13, 1999. http://www.theses.fr/1999PA132007.
Pallot, Lois. "Traitements thermomecaniques de l'alliage de titane Ti-17. Etude expérimentale et modélisation de recristallisation de la phase Beta." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00849211.
Suzon, Eric. "Influence de traitements thermomécaniques sur les textures, microstructures et propriétés élastiques d'un alliage Fe-40at. %AI à grains fins : procédés d'élaboration & traitements de recristallisation statique." Metz, 2004. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2004/Suzon.Eric.SMZ0418.pdf.
This thesis has been carried out to study the thermomechanical treatment effects on textures, microstructures and elastic properties of a fine grain ODS Fe-40at. %Al alloy obtained by consolidation of milled powder. Microstructure has been characterised by SEM and TEM. Textures have been measured by X-Ray Diffraction and by SEM associated with an EBSD system. The texture analysis formation has been completed by simulations using the Taylor model and the anisotropy of elastic properties has been characterised using the Hill model from the measured textures. The effect of several consolidation routes such as extrusion, axial compression and swaging at 1100ʿC is studied. The best Young modulus is obtained for an extruded bar axially compressed by 50% which has a double <110> and <111> fibre texture. The <110> component results from the extrusion and the <111> component from the axial compression and the partial dynamic recrystallization. The microstructure remains fine due to the action of the oxides particles which limit the dynamic recrystallization. The influence of a static recrystallization treatment is also studied. The critical strain to initiate recrystallization is 8% for 1000ʿC annealing treatments. The texture and microstructure of the extruded bar are significantly modified after 10% cold axial compression followed by annealing. A recrystallization kinetic study has allowed to notice that the two steps of the recrystallization - primary recrystallization and grain growth - lead to an anisotropy of the microstructure with large grains elongated in the bar axis. This elongated morphology is strongly connected with the oxides particles alignment in the bar axis. .
Suzon, Eric Pascal Grosdidier Thierry. "Influence de traitements thermomécaniques sur les textures, microstructures et propriétés élastiques d'un alliage Fe-40at.%AI à grains fins procédés d'élaboration & traitements de recristallisation statique /." Metz : Université Metz, 2008. ftp://ftp.scd.univ-metz.fr/pub/Theses/2004/Suzon.Eric.SMZ0418.pdf.
Regle, Hélène. "Alliages ferritiques 14/20% de chrome renforcés par dispersion d'oxydes : effets des procédés de mise en forme sur les textures de déformation, la recristallisation et les propriétés de traction /." Gif-sur-Yvette : Service de documentation et d'édition multimédia, Centre d'études de Saclay, 1994. http://catalogue.bnf.fr/ark:/12148/cb357853259.
Réglé, Hélène. "Alliages ferritiques quatorze et vingt pour cent de chrome renforces par dispersion d'oxydes : effets des procedes de mise en forme sur les textures de deformation, la recristallisation et les proprietes de traction." Paris 11, 1994. http://www.theses.fr/1994PA112097.
Stamoudi, Chrysi. "Processus de serpentinisation des péridotites de Hess-Deep (leg 147, site 895) et de la zone MARK (leg 153, site 920) : approche chimique et minéralogique." Paris 6, 2002. http://www.theses.fr/2002PA066343.