Letteratura scientifica selezionata sul tema "Recuit. microstructure"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Recuit. microstructure".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "Recuit. microstructure"
1
Müller, Martin, Marie Stiefel, Björn-Ivo Bachmann, Dominik Britz e Frank Mücklich. "Overview: Machine Learning for Segmentation and Classification of Complex Steel Microstructures". Metals 14, n. 5 (7 maggio 2024): 553. http://dx.doi.org/10.3390/met14050553.
Testo completoAbstract (sommario):
The foundation of materials science and engineering is the establishment of process–microstructure–property links, which in turn form the basis for materials and process development and optimization. At the heart of this is the characterization and quantification of the material’s microstructure. To date, microstructure quantification has traditionally involved a human deciding what to measure and included labor-intensive manual evaluation. Recent advancements in artificial intelligence (AI) and machine learning (ML) offer exciting new approaches to microstructural quantification, especially classification and semantic segmentation. This promises many benefits, most notably objective, reproducible, and automated analysis, but also quantification of complex microstructures that has not been possible with prior approaches. This review provides an overview of ML applications for microstructure analysis, using complex steel microstructures as examples. Special emphasis is placed on the quantity, quality, and variance of training data, as well as where the ground truth needed for ML comes from, which is usually not sufficiently discussed in the literature. In this context, correlative microscopy plays a key role, as it enables a comprehensive and scale-bridging characterization of complex microstructures, which is necessary to provide an objective and well-founded ground truth and ultimately to implement ML-based approaches.
2
Robson, J. D., O. Engler, C. Sigli, A. Deschamps e W. J. Poole. "Advances in Microstructural Understanding of Wrought Aluminum Alloys". Metallurgical and Materials Transactions A 51, n. 9 (8 luglio 2020): 4377–89. http://dx.doi.org/10.1007/s11661-020-05908-9.
Testo completoAbstract (sommario):
Abstract Wrought aluminum alloys are an attractive option in the quest for lightweight, recyclable, structural materials. Modern wrought aluminum alloys depend on control of complex microstructures to obtain their properties. This requires an understanding of the coupling between alloy composition, processing, and microstructure. This paper summarizes recent work to understand microstructural evolution in such alloys, utilizing the advanced characterization techniques now available such as atom probe tomography, high-resolution electron microscopy, and synchrotron X-ray diffraction and scattering. New insights into precipitation processes, deformation behavior, and texture evolution are discussed. Recent progress in predicting microstructural evolution using computer modeling is also summarized.
3
Chen, Rong, e Xing Zhou. "Recent advances in 2D graphene reinforced metal matrix composites". Nanotechnology 33, n. 6 (15 novembre 2021): 062003. http://dx.doi.org/10.1088/1361-6528/ac2dc7.
Testo completoAbstract (sommario):
Abstract The unique combination of excellent mechanical and functional properties makes graphene an ideal component for high-performance ‘smart’ composites, which are sensitive to thermal, optical, electrical and mechanical excitations, hence being potential in application of a range of sensors. It has confirmed that the addition of graphene into metal matrix can significantly enhance the mechanical property and deliver surprising functional properties. Thus, graphene reinforced metal matrix composites (GMMCs) have long been regarded as potential prospects of nanotechnology applications. Recently, researchers mainly focused on: (i) solving the interfacial issues and realizing controllable alignment of graphene in metal matrix to achieve optimal performance; (ii) reasonable designing of the microstructures basing on usage requirement and then fabricating via efficient technique. Thus, it is necessary to figure out key roles of microstructure in fabrication process, mechanical and multi-functional properties. This review consists of four parts: (i) fabrication process. The fabrication processes are firstly divided into three kinds basing on the different bonding nature between graphene and metal matrix. (ii) Mechanical property. The microstructural characteristics of metal matrix accompanying by the incorporation of graphene and their vital effects on mechanical properties of GMMCs are systematically summarized. (iii) Functional property. The crucial effects of microstructure on electrical and thermal properties are summarized. (iv) Prospect applications and future challenges. Application and challenges basing on the research status are discussed to provide useful directions for future exploration in related fields. All these four parts are discussed with a focus on key role of microstructure characteristics, which is instructive for the microstructures design and fabrication process optimization during academic researches and potential commercial applications.
4
James, R. D. "Microstructure of Shape-Memory and Magnetostrictive Materials". Applied Mechanics Reviews 43, n. 5S (1 maggio 1990): S189—S193. http://dx.doi.org/10.1115/1.3120802.
Testo completoAbstract (sommario):
Recent advances in the analysis of microstructure is providing models and methods for treating the kinds of optimization problems that arise in the study of microstructure. The main advance has been the development of theory and methods for treating the case in which arbitrary microstructures compete for the minimum (or maximum). This contrasts for example with micromechanics in which the geometry of the microstructure is assumed, or assumed up to the choice of a few parameters, and then the optimization or stress analysis is carried out under severe geometric restrictions. Micromechanics is effective in dealing with a particular experimentally observed microstructure, but not for understanding microstructures that might be optimal in a certain sense. Much of this recent research has been fueled by critical discussions among engineering scientists, mathematicians and electron microscopists. The intent of this paper is first to summarize, in terms accessible to a broad audience, the nature of this research and then to describe applications to the improvement of shape-memory and magnetostrictive materials. The general part of the lecture will focus on three areas, effective properties of materials, optimal design of materials and phase transformation and active materials. A central role is played by the question “How does one meaningfully average a quantity whose values vary rapidly on a microstructural scale?” A second recurring theme is that the optimal microstructure is predicted to have fine structure. The latter is closely related to the failure of conditions of material stability.
5
Zheng, Hua, Kai Ming Wu, S. F. Sun e G. W. Hu. "Niobium-Alloyed Steel Treated by Quenching-Partitioning-Tempering". Applied Mechanics and Materials 528 (febbraio 2014): 149–52. http://dx.doi.org/10.4028/www.scientific.net/amm.528.149.
Testo completoAbstract (sommario):
Given the strong recent interest in quenching-partitioning-tempering processed steels, the Niobium-alloyed medium carbon steel was investigated here. The microstructural observations and hardness were analyzed by optical microscope, transmission electron microscope, X-ray diffraction and hardness test. Results show that when quenched at 210°C and partitioned at 450°C, the quenching partitioning-tempering process leads to ultra fine-grained microstructures of martensite, retained austenite and carbides. And the microstructure and hardness changed differently with the increase of partitioned time.
6
Jang, Jeong Gook, e Solmoi Park. "Special Issue: “Microstructures and Durability of Cement-Based Materials”". Materials 14, n. 4 (11 febbraio 2021): 866. http://dx.doi.org/10.3390/ma14040866.
Testo completoAbstract (sommario):
Cement-based materials play an irreplaceable role in building and sustaining our society by meeting the performance demand imposed on structures and sustainability. Cement-based materials are no longer limited to derivatives of Portland cement, and appreciate a wider range of binders that come from various origins. It is therefore of utmost importance for understanding and expanding the relevant knowledge on their microstructure and likely durability performance. This Special Issue “Microstructures and Durability of Cement-Based Materials” presents recent studies reporting microstructural and durability investigation revealing the characteristics of cement-based materials.
7
Lowe, Michael J. "Realistic modelling of microstructural features in numerical simulations of wave propagation in metals". Journal of the Acoustical Society of America 152, n. 4 (ottobre 2022): A293. http://dx.doi.org/10.1121/10.0016323.
Testo completoAbstract (sommario):
Research in numerical modelling in recent years has enabled realistic simulations of wave propagation in three dimensions in large volumes of material, while including features at small scale. A critical enabler has been the growth of computer power, especially Finite Element computations on GPUs. The presentation will start with the development of modelling capability for polycrystalline materials, for which extensive recent work has created realistic simulations for wave speed and grain-scattering attenuation, representing the microstructure at grain scale. This topic has received much attention in theoretical work over several decades, so the simulations have been helpful to evaluate and understand the theoretical models and the physics of the behaviour. Subsequently, the modelling has addressed several other microstructural interests, including simulations for creep damage and fatigue damage, each of which cause reductions of wave speed; models of equivalent macro material properties for these are developed based on studies of the microstructural information. Finally, recent work will be presented on wave propagation and scattering in Titanium alloys containing Macro Textured Regions (MTRs/Macrozones); these comprise microstructures of mixed scale, for which there is interest to use ultrasound to characterise the MTRs (large scale) against a background of a smaller scale regular microstructure.
8
Xi, Shangbin, e Yu Su. "Phase Field Study of the Microstructural Dynamic Evolution and Mechanical Response of NiTi Shape Memory Alloy under Mechanical Loading". Materials 14, n. 1 (2 gennaio 2021): 183. http://dx.doi.org/10.3390/ma14010183.
Testo completoAbstract (sommario):
For the purpose of investigating the microstructural evolution and the mechanical response under applied loads, a new phase field model based on the Ginzburg-Landau theory is developed by designing a free energy function with six potential wells that represent six martensite variants. Two-dimensional phase field simulations show that, in the process of a shape memory effect induced by temperature-stress, the reduction-disappearance of cubic austenite phase and nucleation-growth of monoclinic martensite multi-variants result in a poly-twined martensitic microstructure. The microstructure of martensitic de-twinning consists of different martensite multi-variants in the tension and compression, which reveals the microstructural asymmetry of nickel-titanium (NiTi) alloy in the tension and compression. Furthermore, in the process of super-elasticity induced by tensile or compressive stress, all martensite variants nucleate and expand as the applied stress gradually increases from zero. Whereas, when the applied stress reaches critical stress, only the martensite variants of applied stress-accommodating continue to expand and others fade gradually. Moreover, the twinned martensite microstructures formed in the tension and compression contain different martensite multi-variants. The study of the microstructural dynamic evolution in the phase transformation can provide a significant reference in improving properties of shape memory alloys that researchers have been exploring in recent years.
9
Carter, Joseph G., e George R. Clark. "Classification and Phylogenetic Significance of Molluscan Shell Microstructure". Notes for a Short Course: Studies in Geology 13 (1985): 50–71. http://dx.doi.org/10.1017/s0271164800001093.
Testo completoAbstract (sommario):
Like most classifications of molluscan shell microstructure published during the past 25 years (e.g., MacClintock, 1967; Kobayashi, 1964, 1971; Taylor, Kennedy and Hall, 1969, 1973; Grégoire, 1972a), the present one is based largely on Bøggild's (1930) monographic work, redefined from a modern perspective of combined light and scanning electron microscopy. However, this is the first attempt to integrate shell microstructure terminology for mollusks with that employed by students of bryozoan and brachiopod shell microstructure (e.g., Williams, 1968a,b, 1970, 1973; Williams and Wright, 1970; Armstrong 1968, 1969; Sandberg, 1971, 1977; Brunton, 1972; MacKinnon, 1974, 1977; MacKinnon and Williams, 1974; Iwata, 1981, 1982). An integration of nomenclatorial schemes is desirable for purposes of interphylum comparison, and is presently needed because there is considerable overlap and inconsistency in the application of microstructural terminology even within single molluscan classes. The present synthesis of shell microstructure nomenclature is possible primarily because of the extensive data base of invertebrate shell mineralogy, microstructure and especially ultrastructure published in more than 300 references in the past 15 years. To these data, the authors have contributed original information of shell mineralogy and microstructure for scores of Recent and fossil mollusks, brachiopods and bryozoans, with a clear emphasis on bivalved mollusks. Many inadequately described microstructure terms have been reanalyzed during the course of this study, either by examining species cited in the literature, or by using closely related species. Perhaps because they are better studied, but probably for other reasons as well, the diversity of molluscan shell microstructures is considerably greater than that of brachiopods and bryozoans combined (Carter, 1979). Consequently, most of the present nomenclature is based on mollusks, and only three of the major microstructural arrangements described in this guide (crossed bladed, semi-nacreous and semi-foliated) were known first in brachiopods or bryozoans and later recognized in molluscs.
10
Hanhan, Imad, e Michael D. Sangid. "Design of Low Cost Carbon Fiber Composites via Examining the Micromechanical Stress Distributions in A42 Bean-Shaped versus T650 Circular Fibers". Journal of Composites Science 5, n. 11 (7 novembre 2021): 294. http://dx.doi.org/10.3390/jcs5110294.
Testo completoAbstract (sommario):
Recent advancements have led to new polyacrylonitrile carbon fiber precursors which reduce production costs, yet lead to bean-shaped cross-sections. While these bean-shaped fibers have comparable stiffness and ultimate strength values to typical carbon fibers, their unique morphology results in varying in-plane orientations and different microstructural stress distributions under loading, which are not well understood and can limit failure strength under complex loading scenarios. Therefore, this work used finite element simulations to compare longitudinal stress distributions in A42 (bean-shaped) and T650 (circular) carbon fiber composite microstructures. Specifically, a microscopy image of an A42/P6300 microstructure was processed to instantiate a 3D model, while a Monte Carlo approach (which accounts for size and in-plane orientation distributions) was used to create statistically equivalent A42/P6300 and T650/P6300 microstructures. First, the results showed that the measured in-plane orientations of the A42 carbon fibers for the analyzed specimen had an orderly distribution with peaks at |ϕ|=0∘,180∘. Additionally, the results showed that under 1.5% elongation, the A42/P6300 microstructure reached simulated failure at approximately 2108 MPa, while the T650/P6300 microstructure did not reach failure. A single fiber model showed that this was due to the curvature of A42 fibers which was 3.18 μm−1 higher at the inner corner, yielding a matrix stress that was 7 MPa higher compared to the T650/P6300 microstructure. Overall, this analysis is valuable to engineers designing new components using lower cost carbon fiber composites, based on the micromechanical stress distributions and unique packing abilities resulting from the A42 fiber morphologies.
Tesi sul tema "Recuit. microstructure"
1
Gasmi, Assia. "Effet de la nanostructuration sur le comportement thermomécanique du Nitinol". Electronic Thesis or Diss., Université de Montpellier (2022-....), 2024. http://www.theses.fr/2024UMONS018.
Testo completoAbstract (sommario):
La présente thèse s’intéresse à l'alliage à mémoire de forme NiTi, en se concentrant sur l'influence du procédé de nanostructuration superficielle SMAT sur son comportement thermomécanique. À travers quatre chapitres distincts, elle rappelle les principales caractéristiques des alliages à mémoire de forme (AMF), mettant en avant les propriétés exceptionnelles de l'alliage NiTi, et explorant le traitement de nanocristallisation superficielle (SMAT). La caractérisation microstructurale est ensuite approfondie, notamment en étudiant les effets du traitement thermique de recuit et du SMAT sur la transition de phase. Le troisième chapitre se concentre sur les méthodes d'analyse thermomécanique adaptées au NiTi, en examinant les essais de traction et de nanoindentation. Enfin, le quatrième chapitre analyse la caractérisation thermomécanique de l'alliage avant et après le traitement SMAT, mettant en évidence les implications de ces transformations sur son comportement global.La thèse contribue à la compréhension des effets du procédé SMAT sur l'alliage NiTi, révélant des liens entre la microstructure, les phases présentes et les propriétés mécaniques. Les résultats ouvrent des perspectives prometteuses pour la meilleure maîtrise des propriétés de l'alliage NiTi.Les résultats obtenus pour différents traitements SMAT montrent que ce procédé modifie la réponse mécanique du matériau. Elle a aussi une influence sur son état initial, comme l’illustrent les différences dans les courbes de DSC. Les mesures cinématiques (champs de vitesses de déformation) et calorimétriques (champ de source de chaleur) indiquent aussi l’apparition de différences notables dans les réponses en fonction des paramètres de traitement SMAT. L'exploration du comportement lors de cycles de charge/décharge montre une réponse qui se stabiliser après quelques cycles. Les effets de couplage semblent être prépondérants par rapport aux effets dissipatifs. Ces observations devraient être étendues à des chargements en fatigue afin de mieux mettre en évidence les éventuels effets dissipatifs. De même, l’utilisation de modèles d’interprétation plus élaborés permettrait de mieux tenir compte des effets de structure et d’enrichir la compréhension de la relation entre le procédé et les évolutions des propriétésThis thesis focuses on the shape memory alloy NiTi, with a specific emphasis on the influence of the surface nanostructuring process SMAT on its thermomechanical behavior. Through four distinct chapters, it revisits the main characteristics of shape memory alloys (SMAs), highlighting the exceptional properties of the NiTi alloy and exploring the surface nanocrystallization treatment (SMAT). Microstructural characterization is then deeply investigated, particularly by studying the effects of annealing heat treatment and SMAT on phase transition. The third chapter focuses on thermomechanical analysis methods suitable for NiTi, examining tensile tests and nanoindentation. Finally, the fourth chapter analyzes the thermomechanical characterization of the alloy before and after SMAT treatment, highlighting the implications of these transformations on its overall behavior.This thesis contributes to understanding the effects of the SMAT process on the NiTi alloy, revealing links between microstructure, present phases, and mechanical properties. The results offer promising perspectives for better control of the properties of the NiTi alloy.The results obtained for different SMAT treatments show that this process modifies the mechanical response of the material. It also has an influence on its initial state, as illustrated by differences in DSC curves. Kinematic (strain rate fields) and calorimetric (heat source field) measurements also indicate notable differences in responses depending on SMAT processing parameters. Exploration of behavior during load/unload cycles shows a response that stabilizes after a few cycles. Coupling effects seem to be predominant compared to dissipative effects. These observations should be extended to fatigue loading to better highlight any dissipative effects. Similarly, the use of more elaborate interpretation models would allow better consideration of structural effects and enrich the understanding of the relationship between the process and property evolutions
2
Dabou, Oussama. "Etude de la microstructure, de la texture et des propriétés magnétiques d'un alliage à base de Ni et de Fe après traitement par déformation plastique sévère et recuit". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF020.
Testo completoAbstract (sommario):
Cette thèse propose une étude exhaustive de l'alliage Mumetal, en se penchant sur sa microstructure, sa texture, sa dureté, ses propriétés magnétiques et leurs interrelations. Deux aspects majeurs sont examinés. La première partie se penche sur les changements microstructuraux et mécaniques induits par des techniques de déformation plastique sévère (SPD) telles que le multi coulaminage (ARB), la torsion sous haute pression (HPT) et le pressage ondulé sous contrainte (CGP). Après ARB, la microstructure du Mumetal évolue de grains équiaxes à des grains allongés. Des gradients de dislocation, des changements de texture et une amélioration significative de la dureté sont observés, contribuant tous aux propriétés mécaniques supérieures du matériau. HPT engendre des structures de grains encore plus fines et une dureté accrue. Le CGP, démontre comment la déformation sous température (in situ) peut être exploitée pour améliorer les propriétés mecaniques du Mumetal sans altérer la taille de grain du matériau. La deuxième partie de votre recherche explore les propriétés magnétiques du Mumetal et leur corrélation avec les paramètres microstructuraux et mécaniques. Il est révélé que le raffinement microstructural impacte considérablement les caractéristiques magnétiques du Mumetal.Les propriétés magnétiques sont étroitement liées à l'évolution microstructurale consécutive aux techniques de SPD. Les mesures magnétiques mettent en lumière la relation entre la douceur magnétique du Mumetal et sa dureté mécanique, avec des implications pour son utilisation dans la protection électromagnétique et d'autres technologies. De plus, Le traitement thermomécanique peut être utilisé pour parvenir à un équilibre synergique entre la douceur magnétique et la dureté mécanique. En optimisant les caractéristiques microstructurales, ces matériaux peuvent être adaptés à des applications spécifiquesThis thesis provides a comprehensive study of the Mumetal alloy, delving into its microstructure, texture, hardness, magnetic properties, and their interrelations. It covers two major aspects. The first part examines the microstructural and mechanical changes induced by severe plastic deformation (SPD) techniques such as Accumulative Roll Bonding (ARB), High-Pressure Torsion (HPT), and Constrained Groove Pressing (CGP). ARB transforms the Mumetal's microstructure from equiaxed grains to elongated grains. Dislocation gradients, texture changes, and a significant improvement in hardness contribute to the material's superior mechanical properties. HPT generates even finer grain structures and increased hardness. CGP demonstrates how in-situ deformation under temperature can enhance Mumetal's mechanical properties without altering the material's grain size. The second part explores the magnetic properties of Mumetal and their correlation with microstructural and mechanical parameters. It reveals that microstructural refinement significantly impacts Mumetal's magnetic characteristics. Magnetic properties are closely linked to the microstructural evolution resulting from SPD techniques. Magnetic measurements highlight the relationship between Mumetal's magnetic softness and its mechanical hardness, holding implications for its use in electromagnetic shielding and other technologies. Moreover, thermomechanical treatment can achieve a synergistic balance between magnetic softness and mechanical hardness. By optimizing microstructural features, these materials can be tailored for specific applications
3
Marceaux, Dit Clément Arthur. "Interactions entre transformations de phases et recristallisation au recuit : influence de la microstructure initiale pour des aciers à 0,2 % de carbone". Electronic Thesis or Diss., Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0297.
Testo completoAbstract (sommario):
Les aciers à haute résistance sont très utilisés dans l’industrie automobile pour le bon compromis entre résistance et ductilité qu’ils offrent. D’intenses activités de recherche se poursuivent pour améliorer leurs propriétés de formabilité. Les chimies à fort taux de carbone peuvent aider à atteindre ces objectifs. Cette thèse porte sur les évolutions microstructurales au recuit de deux aciers à 0,2% pds de carbone microalliés au Ti et Nb, dont les microstructures initiales laminées à froid diffèrent (bainite-martensite et bainite-perlite). Les interactions entre la restauration, la recristallisation, la précipitation de cémentite, celle du microalliage et la formation d'austénite peuvent mener à la formation de microstructures finales très variées à l’issue du recuit. La genèse de microstructures en bandes, néfastes pour l’obtention de bonnes propriétés de formabilité et liées à la recristallisation incomplète des aciers lors de leur chauffe, est étudiéeHigh-strength steels are widely used in the automotive industry because of the good mechanical properties – formability ratio they offer. Numerous research activities are still ongoing to further improve their formability properties. High-carbon chemistries can help reach this goal. This thesis focuses on the microstructural evolutions during the annealing of two 0.2 wt.% carbon steels with Ti-Nb microalloy, for which cold-rolled initial microstructures are different (bainite-martensite and bainite-pearlite). Interactions between recovery, recrystallization, cementite precipitation, microalloying elements precipitation and austenite formation can lead to the formation of many kinds of final microstructures after annealing. The origin of banded microstructures, detrimental to good formability properties and linked to incomplete recrystallization during annealing, is studied
4
Kiaei, Mercedeh. "Etude des mécanismes de recristallisation dans des aciers bas carbone". Paris 13, 1996. http://www.theses.fr/1996PA132018.
Testo completoAbstract (sommario):
Les rôles d'acier constituées en aciers a très basse teneur en carbone doivent présenter une excellente aptitude à l'emboutissage. Cette caractéristique importante est liée directement à la texture cristallographique qui influe sur l'anisotropie des propriétés mécaniques des tôles. Dans ce travail, on essaie de comprendre les mécanismes de recristallisation, mal connus jusqu'ici à cause d'un manque de moyens expérimentaux, dans deux nuances d'acier bas carbone laminées à froid à 70%. Les mesures de textures globales ont permis de tirer quelques conclusions sur l'évolution des orientations au cours du recuit. En présence d'azote en solution solide, la texture de recristallisation tend vers l'isotropie. Les précipités de seconde phase, engendrant une germination aléatoire à leur voisinage, réduisent l'amplitude des intensités de textures. Les mesures d'orientations locales, à différentes étapes de recristallisation, montrent que la texture locale des premiers grains est la même que celle des grains en fin de recristallisation. Ce qui montre que la germination contrôle la formation de la texture finale du matériau. En présence d'éléments en solution solide, l'orientation des premiers grains recristallisés correspond aux orientations 100, associées a la sibm, dont la précipitation interagit avec la recristallisation et empêche la croissance. Les essais de recuit in-situ dans un meb ont permis de suivre l'évolution de la microstructure et de la texture locale des aciers laminés à froid pendant la recristallisation. On a ainsi localise les premiers germes de recristallisation, observe leur croissance et l'évolution de leur environnement, et mesure leurs orientations. Les calculs de désorientations entre les grains recristallisés et la matrice révèlent de faibles désorientations au tout début de la recristallisation indiquant une germination intragranulaire. A d'autres étapes de recristallisation, les désorientations se rapprochent du cas sans corrélation. Aucune relation d'orientation de type 27<110> n'a pu être mise en évidence
5
Moreno, Marc. "Mécanismes métallurgiques et leurs interactions au recuit d’aciers ferrito-perlitiques laminés : caractérisation et modélisation". Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0068.
Testo completoAbstract (sommario):
Les aciers Dual Phase (DP) ferrito-martensitiques sont largement utilisés sous la forme de tôles minces dans la construction automobile en raison de leur excellent compromis résistance/ductilité et donc pour leur potentiel d’allègement. Ils sont élaborés par coulée continue, laminage à chaud et à froid suivis d’un recuit continu. Durant l’étape de chauffage et de maintien de ce recuit, la microstructure ferrito-perlitique déformée issue des étapes de laminage se transforme en microstructure ferrito-austénitique recristallisée. L’expérience montre que les cinétiques de recristallisation et de transformation ainsi que la distribution spatiale et morphologique des microstructures résultantes sont très sensibles aux vitesses de chauffage. Ce travail de thèse s’intéresse aux différents mécanismes expliquant cette sensibilité comme la maturation des carbures, la restauration, la recristallisation de la ferrite et la transformation austénitique et toutes leurs interactions. Ces mécanismes métallurgiques ont été caractérisés à différentes échelles et par des approches in situ sur un acier industriel puis modéliser par des approches à base physique pour guider une possible production. Après un premier chapitre dédié aux techniques expérimentales et de modélisations utilisées, le second chapitre de ce travail s’intéresse principalement à la caractérisation de la morphogénèse des microstructures ferrito-austénitique en microscopie électronique à balayage (MEB). Le troisième chapitre est une étude détaillée en Microscopie Electronique à Transmission (MET) et par modélisation thermocinétique (ThermoCalc, DICTRA) de la composition des carbures tout au long du processus, du laminage à chaud au recuit. Restauration et recristallisation sont étudiées au chapitre 4 principalement par des expériences in situ en Diffraction des Rayons X à Haute Energie (DRXHE) sur ligne de lumière synchrotron et modélisées par une approche originale à champs moyen. Enfin, le chapitre 5 propose une étude sous DICTRA pour comprendre les cinétiques de transformation austénitique en fonction des vitesses de chauffe. Cette approche est novatrice car elle prend en compte les carbures intergranulaires de la ferrite, a été conduite en conditions anisothermes et propose une analyse fine des modes de croissance de l’austénite associées au manganèse, élément clef de la composition de ces alliagesFerrite/Martensite Dual-Phase steels are largely used in the form of thin sheets in the automotive industry for their excellent balance between resistance and strength and thus for their lightening potential. They are elaborated by continuous casting, hot- and cold- rolling, followed by a continuous annealing. During the heating and the soaking stages of this latter process, the deformed ferrite/pearlite microstructure obtained after rolling evolves is transformed into a recrystallized ferrite-austenite microstructure. The experiments show that recrystallization and austenite transformation kinetics as well as the resulting spatial and morphological distribution of the phases are highly sensitive to the heating rate. This PhD thesis aims at understanding the different metallurgical mechanisms explaining this particular sensitivity as carbides ripening, recovery, recrystallization and austenite transformation and all their possible interactions. The mechanisms were characterized at different scales and by in situ technics on an industrial steel and model by physical based approaches in order to drive future production lines. After a first chapter dedicated to the experimental and modeling methods, the second chapter deals with the characterization of the morphogenesis of ferrite-austenite microstructures by Scanning Electron Microscopy (SEM). Chapter 3 is a study by Transmission Electron Microscopy (TEM) and by thermokinetic modeling (ThermoCalc, DICTRA) of the chemical composition of carbides along with manufacturing, from hot-rolling to annealing. Recovery and recrystallization are studied in chapter 4 by the means of in situ High Energy X-Ray Diffraction (HEXRD) experiments conducted on a synchrotron beamline and modeled by an original mean-field approach. Finally, chapter 5 proposes an analysis with DICTRA to understand austenite transformation kinetics as function of heating rates. The proposed approach is innovative as it accounts for intergranular carbides in the ferrite matrix, is conducted in non-isothermal conditions and propose a fine analysis of growth modes of austenite associated to manganese, a key alloying element of the studied steels
6
Monchoux, Jean-Philippe. "Influence d'un recuit de ferritisation sur la microstructure et les mécanismes de fissuration en sollicitation monotone et cyclique de la fonte à graphite sphéroïdal perlito-ferritique". Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0004.
Testo completoAbstract (sommario):
L'effet d'un recuit de ferritisation sur les propriétés de rupture de la fonte à graphite sphéroïdal perlito-ferritique n'était pas compris avec précision. Notre but était donc d'une part de caractériser les changements de microstructure se produisant dans la fonte lors du recuit, et d'autre part de caractériser les propriétés de fissuration en sollicitation monotone et cyclique (ténacité en mécanique élasto-plastique de la rupture et fatigue à grand nombre de cycles) avant et après recuit, en vue d'expliquer les modifications de mécanismes de fissuration par les changements microstructuraux observés. Des travaux antérieurs avaient montré l'apparition de particules circonférentielles de ferrite à l'intérieur du sphéroïde après recuit, ces particules ayant un effet endommageant sur l'interface nodule-matrice. Nous avons montré que la formation de ces particules résulte de la dissolution préférentielle du sphéroïde au niveau de défauts cristallins, puis par une globulisation par minimisation d'énergie d'interface des intrusions de matrice ainsi formées. Nous avons également mis en évidence dans la matrice l'existence d'une précipitation fine, probablement de type carbures ɛ, susceptible de conduire à un durcissement de la matrice. Les essais de ténacité ont montré que JIC augmentait après recuit, principalement du fait de la dissolution de la perlite. L'étude en fatigue à grand nombre de cycles a montré une influence importante de la limite d'élasticité sur la durée de vie, ainsi qu'un mécanisme de blocage des microfissures aux joints de grains. Pour ces deux types de sollicitations, les particules circonférentielles n'avaient pas d'effet mesurable, la précipitation influençant la tenue en fatigue par son effet probable sur la limite d'élasticité du matériauThe consequences of a ferritization heat treatment on the microstructure and on the fracture properties (elasto-plastic fracture toughness and high-cycle fatigue) of perlito-ferritic spheroidal graphite cast iron have been investigated. The evolution of the matrix and of the nodule-matrix interface during nodule's dissolution were characterized by means of both scanning and transmission electron microscopy. It was found that the graphite dissolution occurred mainly at crystalline defects. This produced matrix intrusions which were globulized by a surface diffusion phenomenon, leading to an incorporation of matrix particles into the grapite. These particles were found in a previous study to lead to a weakening of the nodule-matrix interface. The matrix study showed the presence of a fine precipitation. The fracture toughness was found to depend mainly on the pearlite fraction in the matrix. The lifetime in fatigue was dependent on the yield stress and on a grain boundary stop phenomenon. The ferritic particles had no or little effect on both fracture toughness and fatigue resistance, the precipitation having an influence on the fatigue resistance by its probable effect on the yield stress
7
Moreno, Marc. "Mécanismes métallurgiques et leurs interactions au recuit d’aciers ferrito-perlitiques laminés : caractérisation et modélisation". Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0068.
Testo completoAbstract (sommario):
Les aciers Dual Phase (DP) ferrito-martensitiques sont largement utilisés sous la forme de tôles minces dans la construction automobile en raison de leur excellent compromis résistance/ductilité et donc pour leur potentiel d’allègement. Ils sont élaborés par coulée continue, laminage à chaud et à froid suivis d’un recuit continu. Durant l’étape de chauffage et de maintien de ce recuit, la microstructure ferrito-perlitique déformée issue des étapes de laminage se transforme en microstructure ferrito-austénitique recristallisée. L’expérience montre que les cinétiques de recristallisation et de transformation ainsi que la distribution spatiale et morphologique des microstructures résultantes sont très sensibles aux vitesses de chauffage. Ce travail de thèse s’intéresse aux différents mécanismes expliquant cette sensibilité comme la maturation des carbures, la restauration, la recristallisation de la ferrite et la transformation austénitique et toutes leurs interactions. Ces mécanismes métallurgiques ont été caractérisés à différentes échelles et par des approches in situ sur un acier industriel puis modéliser par des approches à base physique pour guider une possible production. Après un premier chapitre dédié aux techniques expérimentales et de modélisations utilisées, le second chapitre de ce travail s’intéresse principalement à la caractérisation de la morphogénèse des microstructures ferrito-austénitique en microscopie électronique à balayage (MEB). Le troisième chapitre est une étude détaillée en Microscopie Electronique à Transmission (MET) et par modélisation thermocinétique (ThermoCalc, DICTRA) de la composition des carbures tout au long du processus, du laminage à chaud au recuit. Restauration et recristallisation sont étudiées au chapitre 4 principalement par des expériences in situ en Diffraction des Rayons X à Haute Energie (DRXHE) sur ligne de lumière synchrotron et modélisées par une approche originale à champs moyen. Enfin, le chapitre 5 propose une étude sous DICTRA pour comprendre les cinétiques de transformation austénitique en fonction des vitesses de chauffe. Cette approche est novatrice car elle prend en compte les carbures intergranulaires de la ferrite, a été conduite en conditions anisothermes et propose une analyse fine des modes de croissance de l’austénite associées au manganèse, élément clef de la composition de ces alliagesFerrite/Martensite Dual-Phase steels are largely used in the form of thin sheets in the automotive industry for their excellent balance between resistance and strength and thus for their lightening potential. They are elaborated by continuous casting, hot- and cold- rolling, followed by a continuous annealing. During the heating and the soaking stages of this latter process, the deformed ferrite/pearlite microstructure obtained after rolling evolves is transformed into a recrystallized ferrite-austenite microstructure. The experiments show that recrystallization and austenite transformation kinetics as well as the resulting spatial and morphological distribution of the phases are highly sensitive to the heating rate. This PhD thesis aims at understanding the different metallurgical mechanisms explaining this particular sensitivity as carbides ripening, recovery, recrystallization and austenite transformation and all their possible interactions. The mechanisms were characterized at different scales and by in situ technics on an industrial steel and model by physical based approaches in order to drive future production lines. After a first chapter dedicated to the experimental and modeling methods, the second chapter deals with the characterization of the morphogenesis of ferrite-austenite microstructures by Scanning Electron Microscopy (SEM). Chapter 3 is a study by Transmission Electron Microscopy (TEM) and by thermokinetic modeling (ThermoCalc, DICTRA) of the chemical composition of carbides along with manufacturing, from hot-rolling to annealing. Recovery and recrystallization are studied in chapter 4 by the means of in situ High Energy X-Ray Diffraction (HEXRD) experiments conducted on a synchrotron beamline and modeled by an original mean-field approach. Finally, chapter 5 proposes an analysis with DICTRA to understand austenite transformation kinetics as function of heating rates. The proposed approach is innovative as it accounts for intergranular carbides in the ferrite matrix, is conducted in non-isothermal conditions and propose a fine analysis of growth modes of austenite associated to manganese, a key alloying element of the studied steels
8
Fekecs, André. "Élaboration de photoconducteurs d’InGaAsP par implantation d'ions de fer pour des applications en imagerie proche-infrarouge et spectroscopie térahertz". Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6840.
Testo completoAbstract (sommario):
Cette thèse décrit l’incorporation de fer dans l’hétérostructure InGaAsP/InP par implantation ionique à haute énergie (MeV) suivi d’un recuit thermique rapide. L’alliage quaternaire InGaAsP est tout indiqué pour fabriquer des couches photoconductrices qui peuvent absorber dans le proche-infrarouge, à 1.3 µm ou 1.55 µm. Ce procédé vise à développer de nouveaux matériaux de forte résistivité pour l’holographie photoréfractive et la spectroscopie térahertz pulsée. À notre connaissance, cette investigation représente les premiers essais détaillés de l’implantation de fer dans le matériau InGaAsP/InP. Les principaux paramètres de fabrication, tels la fluence d’ions de fer, la température d’implantation et la température de recuit ont été explorés. Les propriétés physiques des matériaux produits ont été étudiées avec des mesures électriques (résistivité et effet Hall avec l’analyse de Van der Pauw), optiques (photoluminescence, absorption et réflectivité différentielle résolue en temps) et structurales (diffraction de rayons X, canalisation de la rétrodiffusion Rutherford et microscopie électronique en transmission). Pour fabriquer des couches à forte résistivité pour des applications holographiques à 1.3 µm, nos résultats ont montré qu’il est préférable d’éviter l’amorce de l’amorphisation lors de l’implantation du quaternaire pour maintenir une bonne qualité cristalline après recuit. Ceci favoriserait une compensation par l’activation du fer comme impureté profonde. Une résistivité de l’ordre de 10[indice supérieur 4] Ωcm est mesurée après recuit. Pour fabriquer des couches à forte résistivité pour des applications de spectroscopie térahertz pulsée à 1.55 µm, nous privilégions l’amorphisation par implantation froide et la recristallisation, ce qui réduit le temps de recombinaison des photoporteurs sous la picoseconde. L’émission d’ondes térahertz par ce matériau est démontrée sur une largeur de bande de 2 THz. L’évidence expérimentale montre la formation d’une microstructure polycrystalline dans la couche d’InGaAsP, ayant une forte densité de fautes planaires et une taille de grains nanométrique qui varient avec la température de recuit, ce qui suggère une connexion avec les propriétés optoélectroniques du matériau.
9
AKANI, MOHAMED. "Elaboration du silicium polycristallin par projection plasma : microstructure et proprietes electriques". Paris 6, 1986. http://www.theses.fr/1986PA066613.
Testo completoAbstract (sommario):
Obtention de rubans autosupportes ou supportes par differents substrats par projection plasma a partir de poudre de silicium. Optimisation du procede. Mesure des caracteristiques des rubans obtenus (porosite, densite, resistivite, mobilite de hall) avant et apres recuit, et apres recristallisation par bombardement electronique. Evolution des caracteristiques electriques avec le dopage. Mesure des proprietes photoelectroniques
10
Lakhal, Lamyae. "Influence of microstructure on the properties of composite materials reinforced with unidirectional fibers". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I060/document.
Testo completoAbstract (sommario):
L’influence de la microstructure sur l’élasticité à l’échelle macroscopique de matériaux composites renforcés par des fibres alignées sans chevauchement est quantifiée par homogénéisation numérique (FEM). La fonction de paires (Rdf) s’est montrée comme étant la corrélation du second ordre la plus efficace pour décrire la répartition spatiale des fibres. Des échantillons numériques dont la Rdf est contrôlée ont été construits par recuit simulé et leurs propriétés effectives calculées. La condition de non-chevauchement entraine un pic de la Rdf pour des distances comprises entre 1 et 1,5 diamètre. Les coefficients d’élasticité augmentent avec le pic de la Rdf. Ces résultats ont conduit à établir de nouvelles bornes pour les systèmes de fibres parallèles en équilibre. Les microstructures correspondant aux bornes inférieures et supérieures sont respectivement une répartition des fibres de Percus-Yevick et une agglomération des fibresThroughout this work, the influence of microstructures of non-overlapping aligned fiber reinforced composites on macroscopic elastic properties has been quantified with numerical homogenization on FEM simulations. The radial distribution function (Rdf) has proven to be the best second order correlation to describe fiber spatial distributions. Numerical samples with controlled Rdfs were built with simulated annealing and their effective values were evaluated. Due to the non-overlapping condition, Rdf exhibits a peak for distances from 1 to 1.5 diameter. When Rdf peak increases, elastic moduli increase as well. From this result, new bounds that frame any equilibrium system of aligned fiber composites were established. The corresponding microstructures for lower and upper bounds were respectively a Percus-Yevick distribution of fibers and packed fibers
Libri sul tema "Recuit. microstructure"
1
J, Roth Don, e United States. National Aeronautics and Space Administration., a cura di. Recent advances in nondestructive evaluation made possible by novel uses of video systems. [Washington, D.C.]: NASA, 1990.
Cerca il testo completo
2
C-MRS International Conference (1990 Beijing, China). Mechanical properties materials design: Proceedings of the symposia J, Fatigue and fracture behavior in materials, K, Recent advances of tribomaterials, and M, Microstructures and materials design of the C-MRS International 1990 Conference, Beijing, China, 18-22 June 1990. A cura di Wu Boqun e Chinese Materials Research Society. Amsterdam: North-Holland, 1991.
Cerca il testo completo
3
Hopkins, William D., Cheryl D. Stimpson e Chet C. Sherwood. Social cognition and brain organization in chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198728511.003.0014.
Testo completoAbstract (sommario):
Bonobos and chimpanzees are two closely relates species of the genus Pan, yet they exhibit marked differences in anatomy, behaviour and cognition. For this reason, comparative studies on social behaviour, cognition and brain organization between these two species provide important insights into evolutionary models of human origins. This chapter summarizes studies on socio-communicative competencies and social cognition in chimpanzees and bonobos from the authors’ laboratory in comparison to previous reports. Additionally, recent data on species differences and similarities in brain organization in grey matter volume and distribution is presented. Some preliminary findings on microstructural brain organization such as neuropil space and cellular distribution in key neurotransmitters and neuropeptides involved in social behaviour and cognition is presented. Though these studies are in their infancy, the findings point to potentially important differences in brain organization that may underlie bonobo and chimpanzees’ differences in social behaviour, communication and cognition. Les bonobos et les chimpanzés sont deux espèces du genus Pan prochement liées, néanmoins ils montrent des différences anatomiques, comportementales et cognitives marquées. Pour cette raison, les études comparatives sur le comportement social, la cognition et l’organisation corticale entre ces deux espèces fournissent des idées sur les modèles évolutionnaires des origines humaines. Dans ce chapitre, nous résumons des études sur les compétences socio-communicatives et la cognition sociale chez les chimpanzés et les bonobos de notre laboratoire en comparaison avec des rapports précédents. En plus, nous présentons des données récentes sur les différences et similarités d’organisation corticale du volume et distribution de la matière grise entre espèces. Nous présentons plus de résultats préliminaires sur l’organisation corticale microstructurale comme l’espace neuropile et la division cellulaire dans des neurotransmetteurs clés et les neuropeptides impliqués dans le comportement social et la cognition. Bien que ces études sont dans leur enfance, les résultats montrent des différences d’organisation corticale importantes qui sont à la base des différences de comportement social, la communication et la cognition entre les bonobos et les chimpanzés.
4
Passaro, Antony, Foteini Christidi, Vasiliki Tsirka e Andrew C. Papanicolaou. White Matter Connectivity. A cura di Andrew C. Papanicolaou. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199764228.013.5.
Testo completoAbstract (sommario):
The applications of diffusion tensor imaging (DTI) have increased considerably among both normal and diverse neuropsychiatric populations in recent years. In this chapter, the authors examine the contributions of DTI in identifying profiles of trait-specific connectivity in several groups defined in terms of gender, age, handedness, and general intelligence. Additionally, the DTI literature is reviewed across a range of neurodegenerative disorders including Alzheimer’s disease, mild cognitive impairment, frontotemporal dementia, Parkinson disease, multiple sclerosis, and acquired neurological disorders resulting from neuronal injury such as traumatic brain injury, aphasia, agnosia, amnesia, and apraxia. DTI metrics sensitive to psychiatric disorders encompassing obsessive-compulsive disorder, depression, bipolar disorder, schizophrenia, and alcoholism are reviewed. Future uses of DTI as a promising means of confirming diagnoses and identifying in vivo early microstructural changes of patients’ clinical symptoms are discussed.
Capitoli di libri sul tema "Recuit. microstructure"
1
Huth, Nicolas, e Frédéric Abergel. "Some Recent Results on High Frequency Correlation". In Market Microstructure, 61–86. Oxford, UK: John Wiley & Sons Ltd, 2013. http://dx.doi.org/10.1002/9781118673553.ch3.
Testo completo
2
Suga, Tadatomo. "Recent Progress in Surface Activated Bonding". In Ceramic Microstructures, 385–89. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5393-9_36.
Testo completo
3
Ruggeri, Tommaso. "Some Recent Results on Multi-temperature Mixture of Fluids". In Continuous Media with Microstructure, 39–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-11445-8_5.
Testo completo
4
Davis, William J., e Donald W. Davis. "Alpha Recoil Loss of Pb from Baddeleyite Evaluated by High-Resolution Ion Microprobe (SHRIMP II) Depth Profiling and Numerical Modeling". In Microstructural Geochronology, 247–59. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119227250.ch11.
Testo completo
5
Eaves, L., F. W. Sheard e G. A. Toombs. "A Review of Recent Developments in Resonant Tunnelling". In Band Structure Engineering in Semiconductor Microstructures, 149–66. Boston, MA: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4757-0770-0_13.
Testo completo
6
Provan, James W., e Steven R. Bohn. "Microstructure and the Fatigue Reliability of Metals". In Recent Developments in Micromechanics, 162–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-84332-7_12.
Testo completo
7
Piggott, M. R. "Recent Work on Mesostructures and the Mechanics of Fiber Composites". In IUTAM Symposium on Microstructure-Property Interactions in Composite Materials, 289–300. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0059-5_24.
Testo completo
8
Cammarata, Robert C. "Recent Studies of the Supermodulus Effect". In Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures, 193–98. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1765-4_10.
Testo completo
9
Watanabe, Tadao. "The Advent and Recent Progress of Grain Boundary Engineering (GBE): In Focus on GBE for Fracture Control through Texturing". In Microstructural Design of Advanced Engineering Materials, 403–46. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527652815.ch17.
Testo completo
10
Hirschberger, C. Britta, e Paul Steinmann. "Modelling of Microstructured Materials with Micromorphic Continuum Approaches". In Recent Developments and Innovative Applications in Computational Mechanics, 191–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-17484-1_21.
Testo completoAtti di convegni sul tema "Recuit. microstructure"
1
Lolla, T., J. Siefert, H. Lee, J. Kim, K. Hashimoto, N. Komai e K. Tominaga. "Understanding the Kinetics of Sigma Phase Evolution in Super 304H using Lab Creep Tested Heats and Long-term Service Aged Components". In AM-EPRI 2024, 635–49. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.am-epri-2024p0635.
Testo completoAbstract (sommario):
Abstract Super 304H is a new generation of advanced austenitic stainless steels that is increasingly being used in superheater/ reheater (SH/RH) sections of thermal ultra-supercritical steam power plants due to its high creep strength combined with good oxidation resistance and microstructure stability. However, recent studies have shown significant microstructural changes and associated degradation in creep performance during long-term service exposure in this alloy. Microstructure evolution during service and its effect on the long-term creep performance has not been comprehensively assessed. In this work, variations in the microstructure of long-term service exposed Super 304H RH tubes (~99,600 hours at 596°C steam temperature) are documented. The results for the ex-service material are compared to well-documented laboratory studies to provide perspective on improved life management practices for this mainstay advanced stainless steel.
2
Ortolani, M., R. Locatelli, J. Siefert e A. Bridges. "Effect of Manufacturing Process Parameters on Long-Term Microstructural Evolution and Accumulation of Creep Damage in Grade 91 Material". In AM-EPRI 2024, 612–22. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.am-epri-2024p0612.
Testo completoAbstract (sommario):
Abstract Grade 91 creep strength-enhanced ferritic steel is a critical material in power generation, widely used for high-temperature, high-pressure tubing and piping applications. Its superior elevated-temperature strength derives from a distinctive microstructure of tempered martensite with uniformly dispersed secondary phases (carbides and carbo-nitrides). This microstructure, crucial for reliable service performance, is achieved through precise control of the manufacturing process, including steelmaking, hot forming, and final heat treatment. This investigation builds upon earlier research into the relationship between manufacturing parameters and short-term creep-rupture properties in T91 tubes, and a recent update that included test results exceeding 30,000 hours. This study presents a comprehensive metallurgical analysis of ruptured test specimens. The investigation focuses on correlating manufacturing parameters with not only creep strength but also material ductility and microstructural evolution during long-term exposure, providing valuable insights into the material’s behavior under extended service conditions.
3
Sadek, Alber. "Optimization of the Post-Heat Treatment of Additively Manufactured IN625". In IFHTSE 2024, 183–92. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.ifhtse2024p0183.
Testo completoAbstract (sommario):
Abstract Nickel-based Inconel 625 is widely used for both low and high-temperature applications. It has several applications in aerospace, marine, chemical, and petrochemical industries due to its high strength, corrosion resistance, good formability, and weldability. With the molten pool’s rapid solidification during laser powder bed fusion (LPBF), the resulting microstructures differ from those expected in equilibrium conditions. Residual stresses, microsegregation, anisotropy, undesirable phases, layered structure, and lower mechanical properties are the challenges that must be addressed before LPBF-ed Inconel 625 parts can be industrially implemented. Heat treatment of Inconel 625 after the LPBF process is widely discussed in the literature, and the proposed heat treatment processes do not address all the challenges mentioned above. For this reason, specific heat treatments should be designed to achieve desired mechanical properties. Five different high-temperature heat treatment procedures were developed and tested in recent work in comparison with the standard heat treatment for wrought alloy (AMS 5599), to study the effect of various heat treatment parameters on the type of precipitates, grain size, room, and elevated temperature mechanical properties, and to develop an elevated-temperature tensile curve between room temperature (RT) and 760°C of LPBF-ed Inconel 625. Four heat treatment procedures showed complete recrystallization and the formation of equiaxed grain size containing annealed twins and carbide precipitates. However, either eliminating the stress relief cycle or conducting it at a lower temperature resulted in microstructures having the same pool deposition morphology with grains containing dendritic microstructure and epitaxial grains. Two different grain sizes could be obtained, starting with the same as-built microstructure by controlling post-process heat treatment parameters. The first type, coarse grain size (ASTM grain size No. G 4.5), suitable for creep application, was achieved by applying hot isostatic pressing (HIP) followed by solution annealing. The second type, fine-grain size (ASTM grain size No. G 6), preferable for fatigue properties, was achieved by applying solution annealing followed by HIP. The mechanical properties at room and elevated temperature 540°C are higher than the available properties in the AMS 5599 for wrought Inconel 625 while maintaining a higher ductility above the average level found in the standards. It can be concluded that the performed heat treatment achieves higher mechanical properties. The values of ultimate tensile strength (UTS), yield strength (YS), elongation, and reduction of area percentages are similar in the XZ and XY orientations, revealing the presence of isotropic microstructure. The ultimate tensile strength values show an anomalous behavior as a function of the temperature. From the room temperature until around 500°C, there occurs a decrease in the yield strength and a slight increase up to 600°C, decreasing sharply at 700°C. An anomaly is also present in relation to the elongation, with a significant decrease in the elongation at temperatures after 600°C.
4
Ishikawa, Nobuyuki, Toyohisa Shinmiya, Shigeru Endo, Tsunemi Wada e Joe Kondo. "Recent Development in High Strength Linepipe for Sour Environment". In ASME 2003 22nd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2003. http://dx.doi.org/10.1115/omae2003-37065.
Testo completoAbstract (sommario):
This paper firstly summarizes the design concepts for controlling crack resistant property and mechanical properties of high strength linepipe steels for sour gas service. Optimum conditions of controlled rolling and accelerated cooling that balances crack resistant property and toughness were investigated. It was demonstrated that higher cooling rate in accelerated cooling process brings tremendous advantages for balancing toughness and strength by fine bainitic microstructure even for heavy wall thick pipes. Production results of high strength sour resistant linepipes were introduced. In order to increase strength grade of sour linepipes, further investigation was made using the steels with different microstructures. It was found that precipitation hardened ferrite-bainite steels have extremely high resistance against HIC even for Grade X80. Mechanical properties and microstructural characteristics of this newly developed steel were introduced in this paper.
5
Jiang, Quanxin, V. M. Bertolo, V. A. Popovich e Carey L. Walters. "Recent Developments and Challenges of Cleavage Fracture Modelling in Steels: Aspects on Microstructural Mechanics and Local Approach Methods". In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-95464.
Testo completoAbstract (sommario):
Abstract Offshore activity in low-temperature areas requires the use of analysis methods that are capable of reliably predicting cleavage (brittle) fracture of ferritic steels in order to guarantee the structural integrity during service. Cleavage fracture is controlled by physical events at different size scales and is influenced by the multiple microstructural parameters of the material. The prediction of fracture toughness of steels based on the microstructure has received great attention, and relevant techniques have been continuously developed. This paper is aimed at reviewing the recent development of cleavage fracture modelling in steels and identifying the existing challenges to inspire further research. The paper contains three parts aimed at explaining how methods are developed and utilized to predict fracture toughness of steel from its microstructures. (1) The complex multiparametric nature of the microstructures of ferritic steels and its influence on cleavage fracture is introduced. (2) A review is given on the main perspectives and models in micromechanisms of cleavage fracture in steels. (3) Discussion is contributed to the link between micromechanisms and the local approach in cleavage fracture modelling. As a result, the paper gives a state of the art on microstructural mechanics and local approach methods of cleavage fracture modelling in structural steels.
6
Wu, Jing, Mohammad S. Alam, KM Rafidh Hassan, Jeffrey C. Suhling e Pradeep Lall. "Investigation and Comparison of Aging Effects in SAC305 and Doped SAC+X Solders Exposed to Isothermal Aging". In ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipack2020-2695.
Testo completoAbstract (sommario):
Abstract Microstructural evolution occurs in lead free Sn-Ag-Cu (SAC) solder joints exposed to isothermal aging. Such changes lead to degradations in the mechanical properties and creep behavior of the solder, and can result in dramatic reductions in the board level reliability of lead-free electronic assemblies subjected to aging. In our recent research, Scanning Electron Microscopy (SEM) has been used to: (1) monitor aging induced microstructural changes occurring within fixed regions in selected lead-free solder joints, (2) create time-lapse imagery of the microstructure evolution, and (3) analyze the microstructural changes quantitatively and correlate to the observed mechanical behavior evolution. This approach has removed the limitations of many prior studies where aged and non-aged microstructures were taken from two different samples and could only be qualitatively compared. In our current study, the microstructural evolutions were observed in SAC305 (96.5Sn-3.0Ag-0.5Cu) and SAC_Q (SAC+Bi) exposed to isothermal conditions at T = 100 °C and 125 °C for several different regions from several different joints. The microstructures in several fixed regions of interest were recorded after predetermined time intervals of aging, which were 1 hour (up to 270 hours) and 250 hours (up to 7000 hours) for the long-term aging samples. The aging induced changes in microstructure have been correlated with the changes in mechanical behavior measured using uniaxial tensile testing. The area and diameter of each IMC particle were tracked during the aging process using the recorded images and imaging processing software. As expected, the analysis of the evolving SAC305 and SAC+X microstructures showed a significant amount of diffusion of silver and bismuth in the beta-tin matrix during aging. In particular, Ag3Sn particles coalesced during aging leading to a decrease in the number of particles. Any bismuth in the SAC+X microstructure was observed to quickly go into solution, resulting in solid solution strengthening. This primary occurred within the beta-Sn dendrites, but also in the Ag3Sn intermetallic rich regions between dendrites. The presence of bismuth in was also found to slow the diffusion process that coarsens the Ag3Sn IMC particles. The combination solid solution strengthening and a lower diffusion rate for Ag lead to reduced aging effects in the SAC+Bi alloy relative to the SAC305 solder alloy. The SAC_Q alloy was found to have significantly better high temperature mechanical properties relative to SAC305 at all prior aging conditions. In particular, the initial modulus and ultimate tensile strength of SAC305 experienced large degradations during high temperature aging, whereas the same properties of SAC_Q changed only slightly. These changes in mechanical behavior correlated well with the observed increases in the average IMC particle diameter and decreases in the number of IMC particles. The microstructural and material property degradations were especially large for SAC305 during the initial 50 hours of aging.
7
Ishikawa, Nobuyuki, Mitsuhiro Okatsu, Shigeru Endo e Joe Kondo. "Design Concept and Production of High Deformability Linepipe". In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10240.
Testo completoAbstract (sommario):
Extensive studies to develop high deformability linepipe have been conducted. In the case of linepipes laid in seismic region or permafrost field, higher resistance to buckling against large strain induced by ground movement is required. In order to improve the deformability of pipes, two different types of microstructural control technologies were proposed, based on theoretical and analytical studies on the effect of microstructural characteristics on stress-strain behavior. Grade X65 to X100 linepipes with ferrite-bainite microstructure were manufactured by optimizing the microstructural characteristics. Grade X80 linepipe with bainitic microstructure containing dispersed fine MA constituents was also developed by applying new conceptual TMCP process. Deformability of developed linepipes with two different types of microstructure was evaluated by axial compression and bending tests, and all the developed linepipes showed superior resistance to buckling comparing with conventional pipes. Plate manufacturing technologies for producing recent high strength linepipe steel and the concept for microstructure control for improving deformability were also introduced in this paper.
8
Pourkia, Navid, e Morteza Abedini. "Recent Developments of Oil and Gas Transmission Pipeline Steels: Microstructure, Mechanical Properties and Sour Gas Resistance". In 2008 7th International Pipeline Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ipc2008-64153.
Testo completoAbstract (sommario):
In modern oil and gas transmission pipeline steels technology, a suitable microstructure is an important factor for improvement of strength, toughness and sour gas resistance. Therefore, thermo-mechanically controlled rolling processes have been developed and their microstructures have been changed from ferrite-pearlite to acicular ferrite. Moreover in the recent years extensive attempts have been made to improve pipeline steels properties, which include: i) Ultra fine-grained steels, which are produced by optimized usage of dynamic recrystallization and strain-induced transformation with about 1μm equiaxed ferrite grain size. ii) Ultra low carbon steels with less than 0.025 wt% carbon and significant amount of Mo and Nb microalloying elements. iii) Ultra fine acicular ferrite steels, which are produced by application of more accurate controlled thermo mechanical processes and accelerated cooling. iv) Ultra high strength X100 and X120 grade steels, which are produced by thermo-mechanically controlled processes and heavy accelerated cooling. The former is without special technological changes and mainly consist of low carbon upper bainitic microstructure while the latter needs more technological developments with very little amount of boron and mainly consists of lower bainitic microstructure. This paper gives an overview of these new pipeline steels in viewpoint of microstructure, mechanical properties and sour gas resistance. The studies show that ultra fine acicular ferrite is the best alternative microstructure for nowadays ordinary pipeline steels, but because of numerous advantages of ultra high strength pipelines steels which finally reduce the cost of pipeline projects, the trend of the investigations is focused on further development of these steels. Moreover, acicular ferrite microstructure which is generally accepted by pipeline engineers and it is just in doubt because of its differences with acicular ferrite microstructure of weld metal and numerous offered definitions, is completely described.
9
Semjonov, Sergey L. "Recent advances in microstructured optical fibers". In 2014 International Conference Laser Optics. IEEE, 2014. http://dx.doi.org/10.1109/lo.2014.6886483.
Testo completo
10
Schulz, Volker P., Partha P. Mukherjee e Heiko Andra¨. "Compression Modeling and Transport Characterization of the PEM Fuel Cell Diffusion Medium". In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54298.
Testo completoAbstract (sommario):
Despite tremendous progress in recent years, a pivotal performance limitation in PEM fuel cells manifests in terms of mass transport loss owing to liquid water transport and resulting flooding. A key contributor to the mass transport loss is the cathode gas diffusion layer (GDL) due to the blockage of available pore space by liquid water thus rendering hindered oxygen transport to the active reaction sites in the electrode. The GDL, typically a non-woven carbon paper or woven carbon cloth, thus plays an important role in the overall water management in PEM fuel cells. The underlying pore-morphology and the pore wetting characteristics have significant influence on the flooding dynamics in the GDL. Another important factor is the role of cell compression on the GDL microstructural change. In this work, we investigate the influence of GDL microstructure change under compression on the transport behavior. We will present an improved compression model based on the micro finite element approach. The compression of reconstructed GDL microstructures along with effective property estimation and transport characterization are elucidated.
Rapporti di organizzazioni sul tema "Recuit. microstructure"
1
Musinski, William D., Gustavo M. Castelluccio e David L. McDowell. Recent Developments in Assessing Microstructure-Sensitive Early Stage Fatigue of Polycrystals (Postprint). Fort Belvoir, VA: Defense Technical Information Center, aprile 2014. http://dx.doi.org/10.21236/ada603892.
Testo completo
2
Tiku, Pussegoda e Luffman. L52031 In-Situ Pipeline Mechanical Property Characterization. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), giugno 2003. http://dx.doi.org/10.55274/r0011133.
Testo completoAbstract (sommario):
The focus in the present study was to establish whether there is a reasonable correlation between the Charpy Vee Notch (CVN) toughness and the non-destructive Potential Difference (PD) measurements of ferritic-pearlitic steels having a range of CVN toughness values. Complete material characterization was carried out for six steels procured for this program. The characterization included chemical analysis, microstructural information, tensile properties and CVN transition curves. In addition, most of the data including the CVN transition curves were available for five suitable pipe line steels from a recent publication in the literature.
3
Bray, Jonathan, Ross Boulanger, Misko Cubrinovski, Kohji Tokimatsu, Steven Kramer, Thomas O'Rourke, Ellen Rathje, Russell Green, Peter Robertson e Christine Beyzaei. U.S.—New Zealand— Japan International Workshop, Liquefaction-Induced Ground Movement Effects, University of California, Berkeley, California, 2-4 November 2016. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, marzo 2017. http://dx.doi.org/10.55461/gzzx9906.
Testo completoAbstract (sommario):
There is much to learn from the recent New Zealand and Japan earthquakes. These earthquakes produced differing levels of liquefaction-induced ground movements that damaged buildings, bridges, and buried utilities. Along with the often spectacular observations of infrastructure damage, there were many cases where well-built facilities located in areas of liquefaction-induced ground failure were not damaged. Researchers are working on characterizing and learning from these observations of both poor and good performance. The “Liquefaction-Induced Ground Movements Effects” workshop provided an opportunity to take advantage of recent research investments following these earthquake events to develop a path forward for an integrated understanding of how infrastructure performs with various levels of liquefaction. Fifty-five researchers in the field, two-thirds from the U.S. and one-third from New Zealand and Japan, convened in Berkeley, California, in November 2016. The objective of the workshop was to identify research thrusts offering the greatest potential for advancing our capabilities for understanding, evaluating, and mitigating the effects of liquefaction-induced ground movements on structures and lifelines. The workshop also advanced the development of younger researchers by identifying promising research opportunities and approaches, and promoting future collaborations among participants. During the workshop, participants identified five cross-cutting research priorities that need to be addressed to advance our scientific understanding of and engineering procedures for soil liquefaction effects during earthquakes. Accordingly, this report was organized to address five research themes: (1) case history data; (2) integrated site characterization; (3) numerical analysis; (4) challenging soils; and (5) effects and mitigation of liquefaction in the built environment and communities. These research themes provide an integrated approach toward transformative advances in addressing liquefaction hazards worldwide. The archival documentation of liquefaction case history datasets in electronic data repositories for use by the broader research community is critical to accelerating advances in liquefaction research. Many of the available liquefaction case history datasets are not fully documented, published, or shared. Developing and sharing well-documented liquefaction datasets reflect significant research efforts. Therefore, datasets should be published with a permanent DOI, with appropriate citation language for proper acknowledgment in publications that use the data. Integrated site characterization procedures that incorporate qualitative geologic information about the soil deposits at a site and the quantitative information from in situ and laboratory engineering tests of these soils are essential for quantifying and minimizing the uncertainties associated site characterization. Such information is vitally important to help identify potential failure modes and guide in situ testing. At the site scale, one potential way to do this is to use proxies for depositional environments. At the fabric and microstructure scale, the use of multiple in situ tests that induce different levels of strain should be used to characterize soil properties. The development of new in situ testing tools and methods that are more sensitive to soil fabric and microstructure should be continued. The development of robust, validated analytical procedures for evaluating the effects of liquefaction on civil infrastructure persists as a critical research topic. Robust validated analytical procedures would translate into more reliable evaluations of critical civil infrastructure iv performance, support the development of mechanics-based, practice-oriented engineering models, help eliminate suspected biases in our current engineering practices, and facilitate greater integration with structural, hydraulic, and wind engineering analysis capabilities for addressing multi-hazard problems. Effective collaboration across countries and disciplines is essential for developing analytical procedures that are robust across the full spectrum of geologic, infrastructure, and natural hazard loading conditions encountered in practice There are soils that are challenging to characterize, to model, and to evaluate, because their responses differ significantly from those of clean sands: they cannot be sampled and tested effectively using existing procedures, their properties cannot be estimated confidently using existing in situ testing methods, or constitutive models to describe their responses have not yet been developed or validated. Challenging soils include but are not limited to: interbedded soil deposits, intermediate (silty) soils, mine tailings, gravelly soils, crushable soils, aged soils, and cemented soils. New field and laboratory test procedures are required to characterize the responses of these materials to earthquake loadings, physical experiments are required to explore mechanisms, and new soil constitutive models tailored to describe the behavior of such soils are required. Well-documented case histories involving challenging soils where both the poor and good performance of engineered systems are documented are also of high priority. Characterizing and mitigating the effects of liquefaction on the built environment requires understanding its components and interactions as a system, including residential housing, commercial and industrial buildings, public buildings and facilities, and spatially distributed infrastructure, such as electric power, gas and liquid fuel, telecommunication, transportation, water supply, wastewater conveyance/treatment, and flood protection systems. Research to improve the characterization and mitigation of liquefaction effects on the built environment is essential for achieving resiliency. For example, the complex mechanisms of ground deformation caused by liquefaction and building response need to be clarified and the potential bias and dispersion in practice-oriented procedures for quantifying building response to liquefaction need to be quantified. Component-focused and system-performance research on lifeline response to liquefaction is required. Research on component behavior can be advanced by numerical simulations in combination with centrifuge and large-scale soil–structure interaction testing. System response requires advanced network analysis that accounts for the propagation of uncertainty in assessing the effects of liquefaction on large, geographically distributed systems. Lastly, research on liquefaction mitigation strategies, including aspects of ground improvement, structural modification, system health monitoring, and rapid recovery planning, is needed to identify the most effective, cost-efficient, and sustainable measures to improve the response and resiliency of the built environment.