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Статті в журналах з теми "Grains-Oriented":
1
Yumi, Hayashi, Ikuo Shohji, and Hiroshi Miyazawa. "Comparison of Self-Annealing Behaviors in (001)- and (111)-Oriented Electrodeposited Silver Films by In Situ EBSP Analysis." Materials Science Forum 879 (November 2016): 2243–48. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2243.
Анотація:
Self-annealing behaviors of the electrodeposited silver films which preferentially orient in (001) and (111) directions were investigated by in situ EBSP analysis. In the (001)-oriented film, self-annealing starts in storage for a few hours at R. T. and is almost complete after storage for 6 h at R. T. (001)- and (212)-oriented recrystallized grains mainly nucleate, and (001)-oriented grains mainly grow up. In the (111)-oriented film, self-annealing starts in storage for 15 min at R. T. and is almost complete after storage for 1 h at R. T. (111)-, (001)- and (212)-oriented recrystallized grains mainly nucleate, and (111)-oriented grains mainly grow up. The size of recrystallized grains induced in the (111)-oriented film by self-annealing is approximately half that in the (001)-oriented film although the rate of recrystallization in the (111)-oriented film is faster than that in the (001)-oriented one. The area fraction of the preferential orientation after completion of recrystallization saturates in approximately 70% and 50% in the (001)- and (111)-oriented films, respectively.
2
Zhang, Xin Ming, Jian Guo Tang, Yun Lai Deng, and Zhuo Ping Zhou. "Investigation of Inhomogeneous Deformation on Meso-Scale with Crystal Plasticity Finite Element." Materials Science Forum 546-549 (May 2007): 813–18. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.813.
Анотація:
The influence of crystallographic orientation stability on the inhomogeneous deformation on the meso-scale was numerically simulated with the crystal plasticity finite element. The initial microstructures were introduced into the finite element via intra-granular orientation gradient. The results demonstrated that the average orientation for both stable Goss and meta-stable cube oriented grains changed very little in plane strain compression (PSC). And for stable Goss oriented grain, the orientation gradient increased slightly, but for meta-stable cube oriented grain, the orientation gradient increased dramatically. And in spite of the same Taylor factor for both oriented grains, the dissipated averaged energy for cube oriented grain was higher than for Goss oriented grains, and the distribution width of dissipated work in cube oriented grain was also wider than that in Goss oriented grain. Furthermore, there was also strong energy gradient in PSC of cube oriented grain. Both the orientation gradient and energy gradient favor the nucleation of cube grains during recrystallization.
3
Ikeda, Kenichi, Takahiro Yoshihara, Naoki Takata, and Hideharu Nakashima. "Relation between Ridging and Texture Components in Al-Mg-Si Alloy." Materials Science Forum 558-559 (October 2007): 71–76. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.71.
Анотація:
Al-Mg-Si alloy is the suitable material for the automotive body application. However, it is found that a rope-like profile (ridging) develops when the Al-Mg-Si alloy sheet is stretched along the transverse direction. In this study, in order to clarify the formation process of ridging developed in Al-Mg-Si alloy, the relation between ridging and texture components of the sheet was investigated by 3D profile microscope and SEM/EBSD method. It was found that the ridging developed remarkably in the hot-rolled (at higher temperature) and annealed sheets. In ridging sample, there was the band of cube oriented grains (cube band). It was also found that the region of cube band corresponded to the ridges and valleys which caused a rope-like profile in the sheets. It could be thought that the difference of plastic deformability between cube-oriented grains and other oriented grains led to the development of ridging. This assumption is supported by the lower Taylor factor of cube oriented grains than other oriented grains. From these results, it was concluded that the development of ridging was strongly affected by the distribution of cube oriented grains.
4
Titus, E., D. S. Misra, Manoj K. Singh, Pawan K. Tyagi, Abha Misra, F. Le Normand, J. Gracio, and N. Ali. "Growth of (100) oriented diamond grains by the application of lateral temperature gradients across silicon substrates." Journal of Materials Research 19, no. 11 (November 1, 2004): 3206–13. http://dx.doi.org/10.1557/jmr.2004.0433.
Анотація:
Polycrystalline diamond films with a predominant (100) texture were deposited onto silicon substrates using hot-filament chemical vapor deposition. During film deposition, different temperature gradients were created and imposed laterally across the substrate materials. Films grown under a gradient of 100 °C cm−1 displayed large (100) oriented grains. No crystallite (100) orientation was observed in the as-grown films prepared without a temperature gradient. It was observed that the diamond grain size varied as a function of the gradient. The lower gradient resulted in smaller grains and vice versa. Furthermore, the size of the grains was a function of the deposition time. The orientation of the diamond grains changed gradually across the substrate from (100) to (110) orientation as we scanned from the high-temperature to the low-temperature zone. The films were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy. XRD showed strong (400) reflections in the oriented samples. SEM results indicated the presence of smooth diamond surfaces consisting of predominantly (100) oriented platelets. As the (100) oriented diamond grains were grown on top of the (100) oriented silicon substrates, the faces were mostly aligned parallel to the substrate surface resulting in the deposition of a smooth diamond surface. AFM observations revealed the presence of steps located at the boundaries of the oriented grains. FTIR results showed the characteristic difference in hydrogen bonding in the oriented samples and gave useful information about mechanisms responsible for the orientation. Quantitative analysis was carried out to measure the H content in the films, and it was found that the oriented films contained less hydrogen. Our findings suggest that high saturation of carbon and a concentration gradient of sp3 CH2 species can be the key factor in the oriented growth of (100) diamond grains.
5
Hu, Zhiying, Dingheng Zheng, Rong Tu, Meijun Yang, Qizhong Li, Mingxu Han, Song Zhang, Lianmeng Zhang, and Takashi Goto. "Structural Controlling of Highly-Oriented Polycrystal 3C-SiC Bulks via Halide CVD." Materials 12, no. 3 (January 27, 2019): 390. http://dx.doi.org/10.3390/ma12030390.
Анотація:
Highly-oriented polycrystal 3C-SiC bulks were ultra-fast fabricated via halide chemical vapor deposition (CVD) using tetrachlorosilane (SiCl4) and methane (CH4) as precursors. The effects of deposition temperature (Tdep) and total pressure (Ptot) on the orientation and surficial morphology were investigated. The results showed that the growth orientation of 3C-SiC columnar grains was strongly influenced by Tdep. With increasing Tdep, the columnar grains transformed from <111>- to <110>-oriented. The arrangement of <111>-oriented columnar grains was controlled by Ptot. Lotus-, turtle-, thorn-, and strawberry-like surface morphologies were naturally contributed by different arrangements of <111>-oriented grains, and the deposition mechanism was discussed. The wetting behaviors of CVD-SiC samples by molten aluminum were also examined at 1173 K in a high vacuum atmosphere.
6
Riesemeier, H., J. Pattloch, K. Lüders, and V. Müller. "NMR investigations on oriented grains of superconducting YBa2Cu3O7." Solid State Communications 68, no. 2 (October 1988): 251–54. http://dx.doi.org/10.1016/0038-1098(88)91110-6.
7
Imada, Saki, Toshiyuki Isshiki, Nobuyuki Tatemizo, Koji Nishio, Shuichi Mamishin, Yuya Suzuki, Katsuji Ito, et al. "Formation of various-axis-oriented wurtzite nuclei and enlargement of the a-axis-oriented region in AlFeN films deposited on Si(100) substrates." Materials Advances 2, no. 12 (2021): 4075–80. http://dx.doi.org/10.1039/d0ma01026j.
Анотація:
A-axis-oriented single-crystal AlFeN grains grew from randomly oriented small wurtzite grains with deposition time on Si(100). (a) Deposition time dependence of Al K-edge XANES spectra. (b) Theoretical spectra.
8
Kajihara, Katsura, Kazuhide Matsumoto, and Katsushi Matsumoto. "In Situ SEM-EBSP Observations of Recrystallization Texture Formation in Al-3mass%Mg Alloy." Materials Science Forum 519-521 (July 2006): 1579–84. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.1579.
Анотація:
This study presents in situ observations of recrystallization texture formation in Al-3mass%Mg using SEM concurrent with electron back scattering pattern (EBSP) with hot stage. In the present discussion, the emphasis is on the characteristics of the preferred growth or the shrinkage of Cube and other oriented grains. The in-situ observations of recrystallization demonstrate clearly that the nucleation, growth and shrinkage of recrystallized grains occur simultaneously in each orientation in each region. The overall development of recrystallization texture depends on the balance of nucleation/growth and shrinkage/disappearance of each orientation during recrystallization. The preferential growth is determined by the grain boundary mobility between recrystallized grains or the clusters composed of several similar oriented grains, i.e. Cube clusters or S clusters, and neighboring deformed matrix, and the competitive growth with the surrounding grains. On the other hand, the isolated oriented grain and the strain-stored grains tend to shrink and disappear during recrystallization and grain growth.
9
Khor, L., T. Parks, FJ Lincoln, and J. Graham. "The Distribution of Contaminants and the Nature of the Alteration Products in Physically Separated Grains of Altered Ilmenites." Australian Journal of Chemistry 49, no. 8 (1996): 847. http://dx.doi.org/10.1071/ch9960847.
Анотація:
So-called ' ilmenite ', 'leucoxene' and 'rutile' grades of commercial heavy mineral concentrates were fractionated magnetically, in the laboratory. In the less magnetic ractions, secondary TiO2 (both anatase and rutile ), formed by the alteration of ilmenite grains, was separated from primary rutile, on the basis of density. The separated fractions were examined by optical and scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods, thereby insights being gained into the nature of secondary contamination in altered ilmenite. Grains of secondary TiO2 are very porous and report with an effective density <4.0 g/cm3 in a Magstream separator. Nearly all of these grains, which were distinctively fawn or dull grey in colour, were shown to contain epitaxially oriented, polycrystalline rutile , by single-grain XRD. The porosity of the grey grains was fine and uniform, � whereas the fawn grains contained coarse pores within a trellis of the oriented rutile. Randomly oriented anatase powder occurred with the oriented rutile in some fawn grains. Such trellis textures could facilitate the subsequent ingress of contaminants. Electron probe microanalysis (EPMA) indicated considerable variation in the level of contaminants, between grains, but the averaged analyses for a given fraction were in broad agreement with bulk analyses by X-ray fluorescence (XRF). XRD of single grains showed that anatase occurred significantly more often in fawn grains that were extracted from EPMA mounts because of their high levels of contaminants. The anatase may provide a high surface area for adsorption of contaminants, and/or be an indicator of a past environment where 'insoluble' oxides have been more mobile.
10
Miller, K. T., and F. F. Lange. "Highly oriented thin films of cubic zirconia on sapphire through grain growth seeding." Journal of Materials Research 6, no. 11 (November 1991): 2387–92. http://dx.doi.org/10.1557/jmr.1991.2387.
Анотація:
A two-step process has been developed to form highly oriented thin films in material systems with dissimilar crystal structures and interatomic spacings. This processing method utilizes current polycrystalline thin film deposition techniques. In this method, a polycrystalline thin film is first deposited and heat treated to promote its breakup into isolated grains. The breakup process favors those grains that have a low substrate interfacial energy and so produces a film of highly oriented but isolated grains. In the second process step, another polycrystalline thin film is deposited. The remnant grains act as seeds for the growth of a highly oriented thin film. The process is demonstrated through the growth of highly (100) oriented thin films of cubic ZrO2 (25 mol % Y2O3) on (0001) Al2O3 single crystal substrates, a material system in which film and substrate have dissimilar structures and interatomic spacings. Implications for the growth of epitaxial films using this method are discussed.
Дисертації з теми "Grains-Oriented":
1
Nesser, Manar. "Influence of laser treatment with long, short, or ultra-short pulse duration on the magnetic properties and the domain structure of grain-oriented Iron-Silicon steels." Thesis, Amiens, 2021. http://www.theses.fr/2021AMIE0026.
Анотація:
La technologie laser pulsé est l'une des solutions d'optimisation des propriétés électromagnétiques de certains aciers électriques. Cependant, son application industrielle pour différents alliages, différentes épaisseurs ou applications reste limitée. Par ailleurs, l'impact déterministe de cette technique sur la structure magnétique d'un matériau et sur ses performances nécessite des recherches approfondies. De plus, la technique d'ablation laser à impulsions ultra-courtes reste méconnue pour les aciers électriques. Elle représente cependant un potentiel important en terme de procédé reproductible et résilient aux élévations de température. L'objectif général de la thèse est d'étudier l'influence des traitements de surface par laser impulsionnel sur les propriétés magnétiques des aciers électriques de type Fer Silicium à Grains-Orientés afin d'améliorer leurs performances. Il est tout d'abord proposé une classification des différents procédés laser en fonction de la durée d'impulsion, de sa fréquence de répétition, de son intensité et de sa fluence. Trois familles de procédés sont retenues : l'irradiation, la gravure ou "scribing" et l'ablation. Une attention particulière sera portée sur ce dernier. Un des critères particulièrement analysé sera l'efficacité de la conversion d'énergie (i.e. surtout les pertes fer). Pour cela, l'impact de ces procédés laser est étudié à l'aide de modèles d'aimantation dynamique et de pertes, identifiés grâce à des mesures magnétiques par un banc dédié : le banc SST "Single Sheet Tester". Une optimisation des paramètres d'ablation laser est effectuée afin d'assurer une réduction des pertes fer de l'ordre de 20% tout en préservant la perméabilité magnétique en certains points de fonctionnement (inductions moyenne et forte à 50 Hz et basse induction jusqu’à 5000 Hz). Une étude complémentaire avec deux qualités différentes (FeSi GO conventionnel 0,23 mm et FeSi GO HiB 0,28 mm) a aussi permis d'adapter les paramètres et les motifs laser avec l'épaisseur du matériau. Il est également montré que le procédé d'ablation peut résister à des élévations de température supérieures aux autres procédés tout en acceptant l'application d'un revêtement isolant. En outre, une corrélation entre les paramètres énergétiques optiques (énergie d'une impulsion, densité d'énergie cumulative et densité de puissance pic) les motifs et impacts physiques des tracés laser (profondeur de gravures, zone affectée thermiquement, contrainte thermique induite ...) et finalement les paramètres magnétiques identifiés (coefficients de Bertotti ; paramètres du modèle Lambda) est présentée. Cette étude révèle certaines interprétations physiques. De plus, l'impact des traitements laser de surface sur la structure en domaines magnétiques a été analysé en visualisant le changement des domaines magnétiques. Des images magnéto-optiques par la technique MOIF "Magneto-Optical Indicator Film") sont présentés pour une vue d'ensemble sur les domaines principaux entre les tracés laser avec une résolution de l’ordre de 20 m. Des observations plus précises avec une résolution horizontale de l'ordre de 100 nm sont réalisées à l'aide du Microscope à Force Magnétique (MFM) afin d'avoir accès aux détails de cette structure à proximité et sur les tracés laser. Pour conclure, les analyses des paramètres d'ablation laser sont effectuées en assurant une réduction des pertes fer à 50 Hz avec un taux atteignant plus de 30 % pour une induction allant jusque 0,5 T et de l'ordre de 15 % au-dessus de 1,5 T. À plus haute fréquence et à 0,1 T, le taux de réduction peut dépasser 30%. Parallèlement, la perméabilité apparente peut soit être accrue en dessous de 1,2 T (coude de saturation), soit être préservée ou légèrement réduite entre 1,2 T et la saturation. Dans tous les cas, la polarisation J800 > 1,70 T (GO conventionnel) et J800 > 1,80 T (GO HiB) pour un champ magnétique de 800 A/m sera toujours garantie même après traitement laserPulsed laser technology is one of the productive solutions adopted to optimize the electromagnetic properties of certain electrical steels. However, its industrial application on different alloys, thicknesses, or applications remains restricted. Moreover, the deterministic impact of this technique on the magnetic structure of a material and its performance requires deep investigation. Further, the ultra-short pulsed laser ablation technique remains unfamiliar for electrical steels although it represents a vital potential in terms of a repeatable process that withstands high temperatures. The main intention of the thesis is to study the influence of surface laser treatments on the magnetic properties of grain-oriented silicon iron electrical steels in order to improve their performance. A classification of the different laser processes is proposed according to the pulse duration, repetition frequency, power, and laser fluence. Accordingly, three types of treatments are selected: irradiation, scribing, and ablation, with a particular emphasis on the ablation process. Remarkably, the principal criterion analyzed was the energy conversion efficiency (i.e. especially iron losses). On that account, the impact of these laser processes is studied using dynamic magnetization and loss models, identified by magnetic measurements with an SST "Single Sheet Tester" bench. Then, an optimization of the laser ablation parameters is carried out to ensure a reduction in iron losses of around 20% while maintaining the apparent permeability at certain operating points (medium and high inductions at 50 Hz and low inductions up to 5000 Hz). An additional study on two different grades of FeSi GO (conventional 0.23 mm and HiB 0.28 mm) permitted the adaptation of the laser parameters and patterns with the material thickness. Spectacularly, the ablation process has shown more resistance to a higher temperature than other processes. Furthermore, a correlation between the optical energy parameters (pulse energy, cumulative energy density, and peak power density), the patterns and laser impacts (groove depth, heat affected zone, induced thermal stress), and the identified magnetic parameters (Bertotti coefficients; Lambda model parameters) is presented. This study reveals some physical interpretations.Besides, the effect of surface laser treatments on the magnetic domain structure has been analyzed. We visualized the changes in magnetic domains with Magneto-optical images using the MOIF technique (Magneto-Optical Indicator Film) for an overview of the domains between the laser lines with a resolution of about 20 µm. Following this, more precise observations with a horizontal resolution of the order of 100 nm were performed using the Magnetic Force Microscope (MFM), which shows the structural details in the vicinity and in the laser tracing line. To conclude, an optimization of the laser ablation parameters is accomplished ensuring an iron loss reduction at 50 Hz with more than 30% for an induction 0.5 T, and a percentage of 15% for an induction above 1.5 T. At higher frequencies and for 0.1 T, the reduction percentage can exceed the 30%. Concurrently, the apparent permeability can either be enhanced below 1.2 T (saturation inclination) or slightly reduced between 1.2 T and saturation. Anyhow, the polarization J800 > 1.70 T (conventional GO) and J800 > 1.80 T (GO HiB) under a magnetic field of 800 A/m will be guaranteed after laser treatment
2
Penin, Rémi. "Evaluation à priori des performances environnementales d'un noyau magnétique de transformateur triphasé sur la base de tests simplifiés." Thesis, Artois, 2014. http://www.theses.fr/2014ARTO0209/document.
Анотація:
Le transformateur est aujourd’hui l’un des convertisseurs statiques les plus utilisé notamment dans la distribution électrique. Les tôles magnétiques servant à la construction de leurs circuits magnétiques sont devenues de plus en plus performantes permettant une réduction des pertes produites. Néanmoins, les tests normalisés permettant de caractériser les tôles magnétiques ne reflètent pas totalement le comportement énergétique du transformateur. De plus, une autre problématique a gagné en importance durant ces dernières années : le bruit acoustique émis. Malheureusement, il n’y pas encore de lien entre la qualité de la tôle à grains orientés choisie pour construire le circuit magnétique et le bruit acoustiques que va produire celui-ci. L’objectif de cette thèse est de répondre à cette double problématique à partir de tests simplifiés. En effet, de nombreux dispositifs expérimentaux et méthodologies ont été développés tels que la méthode des trois cadres, permettant d’étudier la répartition des pertes fer dans le transformateur, les circuits magnétiques décalés, permettant d’étudier les phénomènes à l’origine des bruit acoustique, et des modèles de transformateurs monophasés et triphasés. De plus, des simulations numériques ont été effectuées afin d’approfondir nos analyses des résultats expérimentaux. L’étude des dispositifs ont permis de mettre en évidence trois paramètres relatifs à la qualité des tôles magnétiques, entrainant des différences de répartition d’induction set donc des différences de répartition de pertes fer, d’une part, et de bruit acoustique dans les transformateurs, d’autre partThe transformer is now a static converter most notably used in electrical distribution. The electrical steel sheet used in the construction of their magnetic circuits have become more efficient to reduce losses occurred. However, standardized tests to characterize the electromagnetic steel do not fully reflect the energy behavior of the transformer. In addition, another issue has gained importance in recent years: the acoustic noise. Unfortunately, there is no link between the quality of grain oriented steel selected to construct the magnetic circuit and acoustic noise that will produce it. The objective of this thesis is to answer this dual problem from simplified test. Indeed, many experimental devices and methodologies have been developed such as the method of three frames, to study the distribution of core losses in the transformer, the magnetic circuits shifted, to study phenomena at the origin of acoustic noise, and models of single and three phase transformers. In addition, numerical simulations were performed to deepen our analysis of the experimental results. The study of the devices have allowed to identify three parameters relating to the quality of grain oriented electrical steel, resulting from differences in the distribution of the flux density and therefore, first, the differences in distribution of core loss and, hand, acoustic noise in transformers
3
Hihat, Nabil. "Modèles quasi 3D pour l'analyse de structures présentant une anisotropie 3D." Thesis, Artois, 2010. http://www.theses.fr/2010ARTO0206/document.
Анотація:
Les travaux présentés dans cette thèse s'inscrivent dans le cadre de l'analyse et la modélisation de la distribution du champ magnétique dans les machines électriques à circuit magnétique feuilleté avec des tôles à grains orientés. L'anisotropie des tôles magnétiques des transformateurs induit des phénomènes 3D complexes au niveau des joints magnétiques où les tôles se chevauchent. Concernant l'augmentation de l'efficacité énergétique des machines tournantes, de nouvelles structures à base de tôles à grains orientés font leur apparition. Néanmoins, simuler finement en 3D un paquet de tôles minces recouvertes d'un isolant de quelques microns d'épaisseur conduit à des temps de calculs très importants.Dans cette optique, nous présentons une méthode d'homogénéisation dont le but est de définir les caractéristiques magnétiques équivalentes d'un empilement quelconque de tôles et d'entrefers. Sa formulation est basée sur la minimisation de l'énergie et la conservation du flux magnétique. Les résultats de cette méthode appliquée à un joint magnétique de transformateur à joints step-lap sont confrontés à des mesures expérimentales et à un modèle élément fini 3D. Ce dernier requiert de connaître les caractéristiques magnétiques des tôles dans les directions de laminage, transverse et normale. La détermination de la perméabilité des tôles dans la direction normale est problématique et constitue un point original de notre étude. Deux méthodes, analytique et numérique, s'appuient sur les mesuresd'un banc de caractérisation en régime statique pour déterminer cette perméabilité normaleThis thesis focuses on the analysis and the modeling the magnetic flux distribution in electrical machines with anisotropic laminated magnetic circuit. The anisotropy of magnetic sheets in transformers induces complex 3D phenomena in step-lap magnetic joints where the sheets are overlapped. Moreover, in order to increase the energy efficiency of rotating machines, new structures based on grain-oriented electrical steel are developed.However, an accurate 3D simulation of a laminated core with thin sheets and insulation of a few microns leads to very large computation time. In this context, we present a homogenization method, which purpose is to define the equivalent magnetic characteristics of any laminated core made of sheets and air gaps. Its formulation is based on the energy minimization and the magnetic flux conservation. The results of this method applied to a step-lap magnetic joint are compared with experimental measurements and a 3D finite element model. The latter requires to know the magnetic characteristics of the sheets in the rolling, transverse and normal directions. The determination of the sheets permeability in the normal direction is problematic and it constitutes an original point of our study.Two methods, analytical and numerical, based on measurements obtained with a static characterization bench makes possible the determination of the normale permeability
4
Cozonac, Dorin. "Conception d'une machine asynchrone haute température." Thesis, Artois, 2015. http://www.theses.fr/2015ARTO0209/document.
Анотація:
Les bobinages des machines électriques tournantes actuelles sont, pour la plupart, isolés avec des matériaux issus de la chimie organique. La limite en température des bobinages actuels se situe au-dessous de 240°C. L’augmentation significative de la température de fonctionnement d’une machine permettrait d’envisager, indirectement, une augmentation de la densité de courant dans les conducteurs actifs. Dans ces conditions, ces nouvelles machines peuvent présenter une puissance, tant massique que volumétrique, supérieures à celles exploitées actuellement. De plus, les matériaux magnétiques permettent vraisemblablement de fonctionner jusqu’à 800°C. La limite technologique actuelle pour les machines est clairement l’isolant des conducteurs électriques. Ce sujet de thèse propose de définir une approche théorique couplée à des validations expérimentales pour définir les matériaux les mieux adaptés aux machines hautes températures en termes de mise en œuvre et de performances électriques. La conception, repensée autour du bobinage, sera concrétisée par le calcul d’une machine asynchrone à haute température (400°C au cœur du bobinage). Le bobinage devra être placé au cœur de la démarche de conception des machines en adaptant les formes et les propriétés des circuits magnétiques aux caractéristiques des nouvelles bobinesThe windings that are currently used in electrical machines are mostly insulated based on organic insulation. The temperature limit of these windings is up to 240°C. Increasing the working temperature of electrical motors means, indirectly the increasing of current density on the main conductors. Therefore these new motors may provide a higher mass and volume power as classical machines. Furthermore, the magnetic materials can work up to 800 °C. Indeed, in reality technical limit today is the wire insulation. The objective of thesis is to define a theoretical approach combined with experimental validations for identify the appropriate electrical materials used on high-temperature electrical machines. Design is fixed around the winding, that will implemented by calculating a high-temperature asynchronous machine (400°C of windings). The windings are placed as the base of machine design and will determine the geometrical shape and properties of magnetic core
5
Rekik, Mahmoud. "Mesure et modélisation du comportement magnéto-mécanique dissipatif des matériaux ferromagnétiques à haute limite élastique sous chargement multiaxial." Thesis, Cachan, Ecole normale supérieure, 2014. http://www.theses.fr/2014DENS0019/document.
Анотація:
Les travaux de recherche discutés dans ce manuscrit concernent la conception des générateurs de puissance électrique pour l'aéronautique. L’augmentation de la puissance massique de ces équipements passe par une augmentation des vitesses de rotation, donc une augmentation des contraintes. Un premier point est de s'assurer de la bonne tenue mécanique des matériaux. Un deuxième point est de pouvoir prendre en compte les modifications du comportement magnétique (et donc in fine du couple) lorsqu'ils sont soumis à un état de contraintes multiaxial. L’étude présentée vise en particulier à illustrer l’influence d'états de contraintes biaxiaux sur le comportement magnétique des matériaux constitutifs du rotor. Le défi repose sur la mise en place de méthodes de caractérisation du comportement magnéto-mécanique dissipatif uniaxial et multiaxial des nuances développées par Aperam et utilisées par Thales Avionics pour leurs applications aéronautiques (en FeCo-2V et Fe-3%Si à grains non orientés). Des essais non conventionnels seront effectués sur des échantillons en forme de croix de manière à s'approcher des contraintes réellement subies par le rotor. Les essais sont effectués sur la machine d'essai triaxiale Astrée du LMT-Cachan. L'état de contraintes est estimé par corrélation d'images et par diffraction des rayons X. Des mesures magnétiques anhystérétiques et de pertes d'énergie sous contraintes sont reportées. D'autre part, un modèle multi-échelle multiaxial, décrivant le comportement d’un VER à partir de l'équilibre énergétique à l'échelle microscopique sera présenté. L’approche est fondée sur la comparaison des énergies libres de chaque domaine. Une comparaison probabiliste est faite pour déterminer les variables internes que sont les fractions volumiques des domaines. Différentes stratégies envisageables pour modéliser la dissipation statique seront discutées. Puis nous présentons l’approche magnéto-élastique que nous avons retenue visant à une meilleure considération de l’effet de la contrainte sur le comportement des matériaux ferromagnétiquesThe research presented in this thesis is motivated by the design of rotors for high speed rotating machines. The increased power density of these devices requires a higher rotation speed, leading to higher levels of centrifugal forces and stress in the rotor. A first point is to ensure good mechanical strength of the materials. A second point is to take into account changes in the magnetic behavior (and ultimately torque) when they are subjected to a multiaxial stress state. The present study aims at exploring the influence of biaxial stress states on the magnetic behavior of the materials of the rotor. The challenge lies in the development of methods for the characterization of the magneto-mechanical dissipative uniaxial and multiaxial behavior of metal sheets developed by Aperam Alloy and used by Thales Avionics for their aeronautical applications (in FeCo-2V and non-oriented Fe-3%Si). Non conventional experiments are performed on cross-shaped samples in order to apply biaxial stress representative of the loadings experienced by rotors of rotating machines. These experiments are performed on a multiaxial testing machine, Astrée. Stress level is estimated thanks to digital image correlation and X-ray diffraction Both anhysteretic and dissipative magnetic responses to magneto-mechanical loadings have been recorded. On the other hand, a multi-scale multiaxial model describing the behavior of a RVE from the energy balance at the microscopic scale is presented. The approach is based on a comparison of the free energy of each domain. A probabilistic comparison is made to determine the volume fraction of domains used as internal variables. Different strategies for modeling the static dissipation are discussed. Then we present the chosen magneto-elastic approach, improving the description of the effect of stress on ferromagnetic materials behavior
Частини книг з теми "Grains-Oriented":
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Cheng, Chuan. "Fast Fabrication of Self-ordered Anodic Porous Alumina on Oriented Aluminum Grains." In Electro-Chemo-Mechanics of Anodic Porous Alumina Nano-Honeycombs: Self-Ordered Growth and Actuation, 105–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-47268-2_7.
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Sasaki, Y., K. Michishita, Y. Higashida, Y. Kubo, K. Nakamura, and K. Takeda. "A Pinning Mechanism of YBaCuO Thin Film Dispersed with Differently-Oriented Crystal Grains." In Advances in Superconductivity XII, 368–70. Tokyo: Springer Japan, 2000. http://dx.doi.org/10.1007/978-4-431-66877-0_108.
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Quispe, Moisés, José Arroyo, Guillermo Kemper, and Jonell Soto. "An Algorithm Oriented to the Classification of Quinoa Grains by Color from Digital Images." In Advances in Intelligent Systems and Computing, 237–47. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-32022-5_23.
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Wang, Hao, Gang Zhou, Jianke Qiu, Lihua Ye, Dongsheng Xu, Jiafeng Lei, David Rugg, Aijun Huang, and Rui Yang. "Grain Boundary-Mediated Lattice Reorientation inα-Titanium to Promote Plastic Deformation in Hard-Oriented Grains." In Proceedings of the 13th World Conference on Titanium, 1893–96. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119296126.ch316.
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Citrawati, Fatayalkadri, Md Zakaria Quadir, Md Zakaria Quadir, and Paul Munroe. "The Effect of Cross-Rolling on the Growth of Goss Grains in a Grain Oriented Silicon Steel." In Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016), 171–78. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119328827.ch25.
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Citrawati, Fatayalkadri, Md Zakaria Quadir, and Paul Munroe. "The Effect of Cross-Rolling on the Growth of Goss Grains in a Grain Oriented Silicon Steel." In Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016), 173–78. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-48770-0_25.
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Duggan, B. J., M. Z. Quadir, and Richard Penelle. "An Examination of Cluster Nucleation of Goss Oriented Grains Formed during Secondary Recrystallisation in an Fe-3.2% Si Electrical Steel." In Materials Science Forum, 723–28. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-443-x.723.
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Suzuki, Mitsumasa, Hitoshi Sakurai, Tomoaki Sakurai, Mitsugu Nagano, and Yoshiei Wakiya. "Growth of 45°-Rotated Grains in C-Axis Oriented YBa2Cu3O7-δ Films on MgO (100) by On-Axis DC Magnetron Sputtering." In Advances in Superconductivity VIII, 969–72. Tokyo: Springer Japan, 1996. http://dx.doi.org/10.1007/978-4-431-66871-8_218.
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Kuznetsov, Pavel, Anna Mozhayko, Ivan Shakirov, Vitaliy Bobyr, Mikhail Staritsyn, and Anton Zhukov. "Modeling of LPBF Scanning Strategy and its Correlation with the Metallic 316 L, 321, and Alnico Magnets Samples Structure." In Advanced Additive Manufacturing [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102073.
Анотація:
This chapter presents the influence of powder bed laser scanning strategy on the crystallographic structure of the fused specimens 316 L, 321 stainless steel, and Alnico magnets. The main parameters affecting structure are as follows—laser power, stripe width, number of repeated passes with different power, and type of scanning (circle, bidirectional or interlaced, etc.). Changes in the crystallographic structure are studied with regard to melt pool geometry, surface temperature, and surface heat transfer. The correlation is shown between stripe width and laser beam focal spot diameter. Depending on the ratio between stripe width and laser beam focal spot diameter one can see growth elongated and oriented grains or quasi-equiaxed non-oriented grains. The influence of the energy input on the melt pool size and the microstructure of the sample is studied. The influence of the scanning mode (bidirectional and circular) on the temperature distribution in the sample and the microstructure of the sample made of Alnico alloy is considered. All these experimental and model examples clearly demonstrate that it is possible to produce a controllable structure during LPBF process building for advanced additive manufacturing.
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Duarte Soliani, Rodrigo. "Agribusiness logistics: an analysis of brazilian soy and corn transport operations." In Tendencias en la investigación universitaria. Una visión desde Latinoamérica. Volumen XV, 5–24. Fondo Editorial Universitario Servando Garcés de la Universidad Politécnica Territorial de Falcón Alonso Gamero / Alianza de Investigadores Internacionales S.A.S., 2021. http://dx.doi.org/10.47212/tendencias2021vol.xv.2.
Анотація:
Soy and corn are the most representative crops in national agricultural production of grains. Logistics activities are directly related to the competitiveness of agricultural commodities on the foreign market, so that the favorable characteristics of the productive segment only become competitive advantages for the country if there is an efficient logistics system. In this sense, the present study aimed to investigate transportation in the context of Brazilian agribusiness, focusing on soy and corn production chains. Thus, from a bibliographic search and semi-structured interviews with executives from the agro-industrial logistics sector, the investigation was oriented to identify and analyze the main logistical aspects related to the flow of Brazilian grain production. For agricultural commodities, logistical costs have a greater influence on competitiveness, as they are goods with low added value and are generally transported in large volumes. This fact makes the waterway and the railway modes more appropriate for the transportation of these products, due to the ability to move large volumes while consuming little fuel, that is, greater energy and economic efficiency in long distance journeys. Among the main aspects of infrastructure and operation identified, the poor state of repair of the Brazilian road network stands out, with only 12.4% of its roads paved; the low density of the tracks of the railroad and waterway systems when compared with other countries; the small participation of waterways (20%) and railways (15%) in the national transportation matrix. In order to be able to monitor the development of its agricultural production, the country needs to invest in the structuring logistics infrastructure, destined to rail, waterway and cabotage services, and to increase the productivity of the existing assets.
Тези доповідей конференцій з теми "Grains-Oriented":
1
Cizelj, Leon, and Heinz Riesch-Oppermann. "Short Intergranular Cracks in Elasto-Plastic Polycrystalline Aggregate." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22534.
Анотація:
Computational algorithms aiming at modeling and visualization of the initiation and growth of intergranular stress corrosion cracks (e.g., in the steam generator tubes) on the grain-size scale have already been proposed. Main focus of the paper addresses the influence of randomly oriented anisotropic elasto-plastic grains on the microscopic stress fields at crack tips. The limited number of calculations indicate that the incompatibility strains, which develop along the boundaries of randomly oriented grains, influence the local stress fields (J-integrals) at crack tips significantly.
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Murugesan, M., E. Sone, A. Simomura, M. Motoyoshi, M. Sawa, K. Fukuda, M. Koyanagi, and T. Fukushima. "Cu-Cu Direct Bonding Through Highly Oriented Cu Grains for 3D-LSI Applications." In 2021 IEEE International 3D Systems Integration Conference (3DIC). IEEE, 2021. http://dx.doi.org/10.1109/3dic52383.2021.9687604.
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Ionita, Valentin, Lucian Petrescu, and Emil Cazacu. "Influence of harmonics' initial phases on magnetic losses in non-oriented grains FeSi sheets." In 2016 International Symposium on Fundamentals of Electrical Engineering (ISFEE). IEEE, 2016. http://dx.doi.org/10.1109/isfee.2016.7803213.
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Nakagawa, Gou, and Tanemasa Asano. "Oriented Growth of Location-Controlled Si Crystal Grains Using Ni Nano-Imprint and Excimer Laser Annealing." In 2007 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2007. http://dx.doi.org/10.7567/ssdm.2007.f-6-5l.
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Cizelj, L., and I. Simonovski. "Multiscale Assessment of Random Polycrystalline Aggregates With Short Cracks." In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89623.
Анотація:
The complete understanding of the incubation and growth of microstructurally short cracks is still somewhat beyond the present state-of-the-art explanations. A good example is the intergranular stress corrosion cracking of Inconel 600 in high-temperature water. An effort was therefore made by the authors to construct a computational model of the crack growth kinetics at the grain-size scale. The main idea is to divide continuum (e.g., polycrystalline aggregate) into a set of sub-continua (grains). Random grain structure is modelled using Voronoi-Dirichlet tessellation. Each grain is assumed to be a monocrystal with random orientation of the crystal lattice. Elastic behaviour of grains is assumed to be anisotropic. Crystal plasticity is used to describe (small to moderate) plastic deformation of monocrystal grains. Explicit geometrical modelling of grain boundaries and triple points allows for the development of the incompatible strains along the grain boundaries and at triple points. Finite element method (ABAQUS) is used to obtain numerical solutions of strain and stress fields. The analysis is currently limited to two-dimensional models. Numerical examples illustrate analysis of about one grain boundary long transgranular cracks. In particular, the dependence of crack tip displacements on the random orientation of neighbouring grains is studied. The limited number of calculations performed indicates that the incompatibility strains, which develop along the boundaries of randomly oriented grains, significantly influence the local stress fields and therefore also the crack tip displacements. First attempts are also made to quantify the preferential growth directions of cracks crossing the discontinuities (e.g., grain boundary).
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Simonovski, I., and L. Cizelj. "The Influence of the Grain Structure Size on Microstructurally Small Cracks." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48340.
Анотація:
Material ageing and fatigue effects play a significant role in safe operation of nuclear power plants. Particular issues are the initialization and propagation of microstructurally small cracks which can represent a significant proportion of a component’s life time. These cracks are still not well understood, one of the reason being that a number of microstructural features have a significant influence on such cracks: crystallographic orientations of grains, grain boundaries, inclusions, voids, material phases, etc. Microstructural features away from the crack have smaller effect on the crack tip parameters. Crack length also plays a role. For a long crack the influence of the surrounding microstructural features will be smaller than for a small crack. A crack of sufficient length can be modeled using classical fracture mechanics methods. The question is when do we reach this point? To try to answer this question we create a model containing a large number of randomly sized, shaped and oriented grains with a crack inserted into a surface grain. Random grain structure is modelled using a given Voronoi tessellation. We then extend the crack up to 7 grains in length and estimate the standard deviation of crack tip opening displacements (CTOD) due to the random crystallographic orientations of the grains surrounding the crack. To account for the deformation mechanism at the grain size scale anisotropic elasticity and crystal plasticity constitutive models are employed. We show that even at crack length equivalent to 7 grains the standard deviation of the crack tip opening displacements due to the surrounding crystallographic orientations is still 7.3% and that from engineering point of view a crack with length of less than 10 average grain sizes can not be taken as independent of the surrounding microstructural features.
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Thomas, Manuel, Raghu V. Prakash, Ganesh Sundararaman, and Vasudevan Muthukumaran. "Fatigue Crack Growth Rate Studies on Stainless Steel Welds." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86915.
Анотація:
The low carbon, nitrogen enhanced SS 304 L(N) stainless steels are one of the most potential candidates for the structural members in chemical industries and powerplants operating at hostile environments of temperature and corrosion. In service, the structural members fabricated using welding process, when subjected to a combination of mechanical load and elevated temperature can fail by fatigue. The Welding of Austenitic stainless steels using Tungsten Inert gas (TIG) is often limited by the depth of weld penetration, which can be achieved during a single pass. This necessitates for the use of multiple passes resulting in weld distortion and generation of residual stress. The Use of an electronegative flux (Activating flux) during the TIG welding (A-TIG) is known to enhance the weld penetration, thereby reducing the number of passes. The present study evaluates the fatigue crack growth in stainless steel weldment (304L(N) welds) joined using conventional Multipass TIG welding and Activated flux TIG welding at 673K. Compact Tension (C(T)) specimens having a width of 50.8 mm and a thickness of 4 mm were extracted from the location of heat-affected zone (HAZ) and weld metal (WM) for A-TIG and MP-TIG configurations. From the micro-structural evaluation of A-TIG welds, it is noted that high heat input in a single pass has favored the formation of coarse equiaxed grains along the weld center. The use of multiple passes at reduced heat input has resulted in the formation of finer grains, with the orientation of grains changing along each weld pass interface. This finer randomly oriented grains has resulted in increasing crack path resistance through the MP-TIG welds compared to A-TIG welds. Thus from a view point of fatigue crack growth, due to the presence of fine grains, conventional Multi-pass weld is superior compared to A-TIG, but in cases where there is a creep or creep-fatigue combination, the A-TIG weld may prove to be useful.
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Simonovski, I., and L. Cizelj. "The Influence of Crystallographic Orientations of Grains on Microstructurally Small Cracks Using Crystal Plasticity and Random Grain Structure." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93363.
Анотація:
A plane-strain finite element crystal plasticity model of microstructurally small stationary crack emanating at a surface grain in a 316L stainless steel is proposed. The model consisting of 212 randomly shaped, sized and oriented grains is loaded monotonically in uniaxial tension to a maximum load of 1.12Rp0.2 (280 MPa). The influence that a random grain structure imposes on a Stage I crack is assessed by calculating the crack tip opening (CTOD) and sliding displacements (CTSD), considering also different crystallographic orientations. It is shown that certain crystallographic orientations result in a cluster of soft grains around the crack-containing grain. In these cases the crack tip can become apart of the localized strain, resulting in a large CTOD value. This effect, resulting from the overall grain orientations and sizes, can have a greater impact on the CTOD than the local grain orientation. On the other hand, when a localized soft response is formed away from the crack, the localized strain does not affect the crack tip directly, resulting in a small CTOD value. The resulting difference in CTOD can be up to a factor of 4, depending upon the crystallographic set. Grains as far as 6xCracklength significantly influence that crack tip parameters. It was also found the a larger crack-containing grain tends to increase the CTOD.
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Wielage, B., S. Steinhäuser, W. Milewski, and H. Pokhmurska. "Solidification of Detonation Sprayed Ceramic Coating Melted by CO2 Laser." In ITSC2002, edited by C. C. Berndt and E. Lugscheider. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2002. http://dx.doi.org/10.31399/asm.cp.itsc2002p1020.
Анотація:
Abstract This paper investigates the effect of laser treatment on alumina-TiO2 coatings deposited by detonation spraying. It describes the changes observed in the microstructure and hardness of the remelted layers. The originally lamellar structure is transformed into a fine, pore-free columnar structure in which the grains are oriented perpendicular to the interface between the layer and substrate. The remelted zones contain alpha-aluminum oxide as the main phase and are characterized by high microhardness, although a few defects were observed on the periphery. Paper includes a German-language abstract.
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Simonovski, I., and L. Cizelj. "The Vanishing Influence of Microstructure on Growing Short Cracks." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75662.
Анотація:
Microstructural features play a prominent role in the initialization and propagation of microstructurally short cracks. These features include crystallographic orientations of grains, grain boundaries, inclusions, voids, material phases, etc. Their influence is expected to vanish both with increased distance from the crack tip as well as with increased crack length. Current engineering fracture mechanics techniques do not account for these features and can therefore only be applied to sufficiently long cracks. From the engineering point of view it is therefore quite useful to have an estimate of this length. In this paper we build upon the authors’ previous work to estimate decreasing influence from the surrounding microstructural features with increasing crack length. To achieve this, a model containing a large number of randomly sized, shaped and oriented grains is employed. The grain structure is modeled using a Voronoi tessellation. A series of cracks with lengths from one to several grain lengths are inserted into the model, extending from a grain at the surface towards the interior of the model. The crack tip opening displacements (CTOD) are estimated and statistically analyzed for a series of random crystallographic orientation sets assigned to the grains adjacent to the crack. Anisotropic elasticity and crystal plasticity constitutive models are employed at the grain size scale. A rapid decrease of the CTOD scatter is observed with increasing crack length showing a clear tendency to stabilize at standard deviation of about 5% at the effective crack length of about 6 average grain sizes (0.3 mm in AISI 316 stainless steel. A crack with the length exceeding about 10 average grain sizes can be safely taken as a macroscopic crack.