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Littérature scientifique sur le sujet « Phase transformation interfaces »

Auteur : Grafiati
Publié le 1 février 2025

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Articles de revues sur le sujet "Phase transformation interfaces"

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Farahani, Hussein, Gerrit Zijlstra, Maria Giuseppina Mecozzi, Václav Ocelík, Jeff Th M. De Hosson et Sybrand van der Zwaag. « In Situ High-Temperature EBSD and 3D Phase Field Studies of the Austenite–Ferrite Transformation in a Medium Mn Steel ». Microscopy and Microanalysis 25, no 3 (12 avril 2019) : 639–55. http://dx.doi.org/10.1017/s143192761900031x.

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AbstractIn this research, in situ high-temperature electron backscattered diffraction (EBSD) mapping is applied to record and analyze the migration of the α/γ interfaces during cyclic austenite–ferrite phase transformations in a medium manganese steel. The experimental study is supplemented with related 3D phase field (PF) simulations to better understand the 2D EBSD observations in the context of the 3D transformation events taking place below the surface. The in situ EBSD observations and PF simulations show an overall transformation behavior qualitatively similar to that measured in dilatometry. The behavior and kinetics of individual austenite–ferrite interfaces during the transformation is found to have a wide scatter around the average interface behavior deduced on the basis of the dilatometric measurements. The trajectories of selected characteristic interfaces are analyzed in detail and yield insight into the effect of local conditions in the vicinity of interfaces on their motion, as well as the misguiding effects of 2D observations of processes taking place in 3D.
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Fischer, F. D., N. K. Simha et J. Svoboda. « Kinetics of Diffusional Phase Transformation in Multicomponent Elastic-Plastic Materials ». Journal of Engineering Materials and Technology 125, no 3 (1 juillet 2003) : 266–76. http://dx.doi.org/10.1115/1.1586939.

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The goal of this paper is to derive a micromechanics framework to study the kinetics of transformation due to interface migration in elastic-plastic materials. Both coherent and incoherent interfaces as well as interstitial and substitutional atomic diffusion are considered, and diffusional transformations are contrasted with martensitic ones. Assuming the same dissipation for the rearrangement of all substitutional components and no dissipation due to diffusion in an interface in the case of a multicomponent diffusional transformation, we show that the chemical driving force of the interface motion is represented by the jump in the chemical potential of the lattice forming constituent. Next, the mechanical driving force is shown to have the same form for both coherent and frictionless (sliding) interfaces in an elastic-plastic material. Using micromechanics arguments we show that the dissipation and consequently the average mechanical driving force at the interface due to transformation in a microregion can be estimated in terms of the bulk fields. By combining the chemical and mechanical parts, we obtain the kinetic equation for the volume fraction of the transformed phase due to a multicomponent diffusional transformation. Finally, the communication between individual microregions and the macroscale is expressed by proper parameters and initial as well as boundary conditions. This concept can be implemented into standard frameworks of computational mechanics.
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Fang, Hui, Qianyu Tang, Qingyu Zhang, Yiming Fan, Shiyan Pan, Markus Rettenmayr et Mingfang Zhu. « Simulation of the Peritectic Phase Transition in Fe-C Alloys ». Materials 15, no 2 (11 janvier 2022) : 537. http://dx.doi.org/10.3390/ma15020537.

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In this work, a multi-phase cellular automaton (CA) model is extended for the quantitative simulation of peritectic phase transition. First, the effects of cooling rate/supersaturation and temperature on the peritectic transformation kinetics in Fe-C alloys are investigated by utilizing the present CA model. The CA simulations show that supersaturations in the parent phases (liquid and δ-ferrite) increase the L/γ interface growth velocity remarkably, but tinily for the δ/γ interface migration velocity. There exists a transition supersaturation for isothermal transformations, at which the growth rates of the two interfaces are equal. The transition supersaturation is found to increase with decreasing temperature. Microstructural evolution at different cooling rates during peritectic transformation is simulated using the experimental conditions. At low cooling rates, the δ/γ interface propagates at a higher velocity than the L/γ interface. At high cooling rates, however, the γ-phase grows more into the L-phase with a cellular morphology. Then, the proposed CA model is applied to simulate the microstructural evolution during peritectic reaction. It is observed that the γ-phase propagates along the L/δ interface and finally encircles the δ-phase. Meanwhile, the intervenient γ-phase grows in thickness through peritectic transformation. The CA simulations are compared reasonably well with the experimental data and analytical calculations.
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Zhang, Hongliang, Jianqi Xi, Ranran Su, Xuanxin Hu, Jun Young Kim, Shuguang Wei, Chenyu Zhang, Liqun Shi et Izabela Szlufarska. « Enhancing the phase stability of ceramics under radiation via multilayer engineering ». Science Advances 7, no 26 (juin 2021) : eabg7678. http://dx.doi.org/10.1126/sciadv.abg7678.

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In metallic systems, increasing the density of interfaces has been shown to be a promising strategy for annealing defects introduced during irradiation. The role of interfaces during irradiation of ceramics is more unclear because of the complex defect energy landscape that exists in these materials. Here, we report the effects of interfaces on radiation-induced phase transformation and chemical composition changes in SiC-Ti3SiC2-TiCx multilayer materials based on combined transmission electron microscopy (TEM) analysis and first-principles calculations. We found that the undesirable phase transformation of Ti3SiC2 is substantially enhanced near the SiC/Ti3SiC2 interface, and it is suppressed near the Ti3SiC2/TiC interface. The results have been explained by ab initio calculations of trends in defect segregation to the above interfaces. Our finding suggests that the phase stability of Ti3SiC2 under irradiation can be improved by adding TiCx, and it demonstrates that, in ceramics, interfaces are not necessarily beneficial to radiation resistance.
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Weatherly, G. C. « Interfaces and precipitation ». Proceedings, annual meeting, Electron Microscopy Society of America 50, no 1 (août 1992) : 224–25. http://dx.doi.org/10.1017/s0424820100121521.

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An important class of alloy transformation involves the precipitation of a body-centred cubic phase in a close packed cubic or hexagonal matrix (or vice-versa). In the past ten years, numerous investigations have demonstrated that the precipitate grows as a lath or needle-shaped particle, with the growth direction of the axis of the particle parallel to an invariant line of the phase transformation. Although there are an infinite number of potential invariant lines in such a transformation, commonly one observes that the growth direction is close to the common close-packed directions e.g. <110>f and <111>b, with a rational or near-rational orientation relationship between the two phases. These observations can be rationalized by invoking the geometric principles embodied in Bollmann's O-lattice theory or by appealing to the minimization of strain energy principle associated with the set(s) of misfit dislocations lying parallel to the invariant line. Figure 1 shows an example of this characteristic morphology of a lath of γ (face—centred) precipitated in a matrix of α (body-centred) in a two-phase stainless steel. The lath is bounded by well-developed facet planes_(see Fig. 1) with a growth direction about 5° from the common close packed [111]α, [101]γ directions. Sets of misfit dislocations and steps are visible at the (416)α and (275)α facet planes.
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Zhang, Hengzhong, et Jillian F. Banfield. « Phase transformation of nanocrystalline anatase-to-rutile via combined interface and surface nucleation ». Journal of Materials Research 15, no 2 (février 2000) : 437–48. http://dx.doi.org/10.1557/jmr.2000.0067.

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The kinetics of phase transformation of nanocrystalline anatase samples was studied using x-ray diffraction at temperatures ranging from 600 to 1150 °C. Kinetic data were analyzed with an interface nucleation model and a newly proposed kinetic model for combined interface and surface nucleation. Results revealed that the activation energy of nucleation is size dependent. In anatase samples with denser particle packing, rutile nucleates primarily at interfaces between contacting anatase particles. In anatase samples with less dense particle packing, rutile nucleates at both interfaces and free surfaces of anatase particles. The predominant nucleation mode may change from interface nucleation at low temperatures to surface nucleation at intermediate temperatures and to bulk nucleation at very high temperatures. Alumina particles dispersed among the anatase particles can effectively reduce the probability of interface nucleation at all temperatures.
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Zhang, Wen-Zheng. « Reproducible Orientation Relationships Developed from Phase Transformations—Role of Interfaces ». Crystals 10, no 11 (16 novembre 2020) : 1042. http://dx.doi.org/10.3390/cryst10111042.

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The orientation relationship (OR) between phases related by a phase transformation is often reproducible. This study interprets and predicts the reproducible ORs with a two-stage approach. The initial OR formed at the nucleation stage tends to allow a periodic structure of a preferred state to form in the interface. A matching correspondence of either a one-to-one or n-to-m nature can be specified in the periodic structure. An initial OR will become the final reproducible OR if there is no misfit. Otherwise, a reproducible OR developed at the growth stage tends to permit a singular dislocation structure to form in an interface where the preferred state must be sustained locally. The actual change in the OR is subject to the given material system and the phase-transformation condition. Various singular dislocation structures and their constraints on the ORs are analyzed, with thermodynamics and kinetics applied conceptually. The resulting ORs can be specified by following one or more Δg parallelism rules. A set of workable steps is provided to facilitate the interpretation of observed reproducible ORs. Some unsolved problems are identified, which call for further studies that can quantitatively combine the thermodynamics, kinetics and crystallography of phase transformations.
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Howe, James M. « Atomic Structure, Composition, Mechanisms and Dynamics of Transformation Interfaces in Diffusional Phase Transformations ». Materials Transactions, JIM 39, no 1 (1998) : 3–23. http://dx.doi.org/10.2320/matertrans1989.39.3.

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Rettenmayr, Markus, Oleg Kashin et Stephanie Lippmann. « Simulation of Liquid Film Migration during Melting ». Materials Science Forum 790-791 (mai 2014) : 127–32. http://dx.doi.org/10.4028/www.scientific.net/msf.790-791.127.

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Melting of a single-phase polycrystalline material is known to start by the formation of liquid films at the surface and at grain boundaries. The internal liquid films are not necessarily quiescent, but can migrate to avoid/reduce supersaturation in the solid phase. The migration is discussed in the literature to be governed by coherency strains of the solid/liquid interface, by concentration gradients in the liquid or by concentration gradients in the solid phase. A phase transformation model for diffusional phase transformations considering interface thermodynamics (possible deviations from local deviations) has been put up to describe the migration of the solid/liquid (trailing) and the liquid/solid (leading) interfaces of the liquid film. New experimental results on melting in a temperature gradient in combination with simulation calculations reveal that concentration fluctuations in the liquid phase trigger the liquid film migration and determine the migration direction, until after a short time in the order of microseconds the process is governed by diffusion in the solid phase.
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Zhang, J. X., et H. Q. Ye. « Deformation-induced α2 ↔ γ phase transformation in a Ti–48Al–2Cr alloy ». Journal of Materials Research 15, no 10 (octobre 2000) : 2145–50. http://dx.doi.org/10.1557/jmr.2000.0309.

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The structure of γ–α2 interfaces in deformed Ti–48Al–2Cr alloy was analyzed by high-resolution transmission electron microscopy (HREM) and image simulations. Growth of γ–TiAl plate in α2–Ti3Al phase was found to be a result of a ledge mechanism consisting of Shockley partial dislocations on alternate (0001)α2 planes. The height of the ledges was always a multiple of two (0001)α2 planes. The γ → α2 phase transformation was also an interface-related process. Large ledges of six close packed planes (111)γ high were often observed at the γ–α2 interface. Every large ledge consisted of six Shockley partial dislocations that originated from the γ–a2 interfacial lattice misfit. The movement of these partial dislocations accomplished the transformation of γ → α2 phase. Comparing the experimental and simulated HREM image, it was found that atomic reordering appears during the deformation-induced γ↔α2 transformation.
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Thèses sur le sujet "Phase transformation interfaces"

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Jedrecy, Alexandre. « Study of phase transformation of matter through topological coordinates ». Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS386.

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Au cours de cette thèse deux problèmes majeurs pour l’eau ont été étudiés : la transition liquide-liquide et la nucléation homogène de la glace. Pour cela nous avons utilisé l'état de l'art des méthodes d’échantillonnage amélioré, couplé avec une nouvelle variable qui contient les informations topologiques pertinentes des systèmes étudiés, le PIV. En calculant des profils d'énergie libre pour différentes conditions de pression et de température, nous avons pu montrer rigoureusement l’absence de barrière d’énergie libre et de second point critique pour la transition liquide-liquide avec le modèle TIP4P/2005. En échantillonnant l'ensemble des chemins de transition grâce à un nouvel algorithme TPS, nous avons aussi pu étudier précisément le mécanisme de nucléation homogène de l’eau avec le modèle TIP4P/Ice, montrant que la structure optimale des noyaux critiques est un empilement désordonné, les noyaux critiques purement cubique ou hexagonaux évoluant spontanément vers cette structure. De plus, nous avons pu montrer que la glace hexagonale s’agrégeait majoritairement en deux étapes, là où la glace cubique s’agrégeait en une étape. Finalement nous avons quantifié rigoureusement la qualité de notre métrique topologique PIV comme coordonnée de réaction pour étudier la nucléation : une analyse réalisée avec la méthode d'optimisation de la vraisemblance maximale basée sur la fonction de réalisation, indique que cette coordonnée surpasse un large éventail de coordonnées utilisées précédemment pour étudier ce problème
During this thesis two major problems were studied : the liquid-liquid transition and the homogeneous nucleation of ice in water. To achieve this, we used state-of-the-art enhanced sampling methods, coupled with a new collective variable which store the relevant topological information of a system, the PIV. By rigorous calculation of free energy profile for various conditions of pressure and temperature, we have been able to show the lack of free energy barrier and thereof a second critical point for the liquid-liquid transition, with the TIP4P/2005 model of water. By sampling the transition path ensemble with a new TPS algorithm, we have been able to precisely study the homogeneous nucleation of ice in water with the TIP4P/Ice model, showing that critical nuclei arrange themselves optimaly in stacking disorder ice, with purely hexagonal or cubic nuclei spontaneously evolving toward this structure. The insight we obtained includes a two-step mechanism for the aggregation of new hexagonal ice molecules to the critical nucleus, compared to a one-step process for the addition of cubic ice molecules. Finally we performed a quantitative assessment of the quality of the PIV topological metric as reaction coordinate for nucleation : analysis by means of a rigorous likelihood optimization technique based on committor information, indicates that this coordinate outperforms a large set of previously considered coordinates
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Abdedou, Nazim. « Non-equilibrium conditions at solid/liquid interfaces ». Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0346.

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Notre travail porte sur la fusion dite solutale survenant lorsque l'on met deux métaux en contact à une température comprise entre leurs températures de fusion respectives. L'interface solide/liquide se retrouve initialement fortement hors-équilibre et la cinétique propre à son retour à l'équilibre semble mettre en défaut les modèles généralement employés pour décrire la solidification et la fusion. Pour progresser dans la compréhension du processus, nous avons abordé le problème sous trois angles complémentaires. Dans un premier temps, nous avons réalisé des expériences in-situ de fusion solutale du système Au-Ag en utilisant la tomographie par rayons X. L'analyse critique des résultats semble montrer que l'interface solide-liquide reste hors équilibre pendant la fusion solutale, avec la persistance inattendue de gradients de concentration à la fin des expériences. Dans un deuxième temps, dans le but de mieux comprendre les expériences, nous avons mis en œuvre un modèle reposant sur la thermodynamique des processus irréversibles appliquée aux échanges d'espèces chimiques à travers une interface solide/liquide abrupte. Une paramétrisation des coefficients de transfert interfaciaux permet au modèle de reproduire qualitativement les comportements observés dans les expériences. Enfin, nous avons cherché à justifier les paramètres cinétiques du modèle thermodynamique en utilisant la dynamique moléculaire (DM) dans le système Cu-Ni. Nous avons ainsi démontré que les coefficients interfaciaux dépendent des concentrations à l'interface, en accord avec la paramétrisation du modèle thermodynamique
Our work focuses on solutal melting, which occurs when two metals are brought into contact at a temperature between their respective melting temperatures. The solid/liquid interface is initially far from equilibrium, and the kinetics governing its return to equilibrium appear to challenge the models commonly used to describe solidification and melting. To advance our understanding of the process, we approached the problem from three complementary angles. First, we conducted in-situ experiments on the solutal melting of the Au-Ag system using X-ray tomography. Critical analysis of the results appears to indicate that the solid-liquid interface remains out of equilibrium during solutal melting, with the unexpected persistence of concentration gradients at the end of the experiments. Second, in an effort to better understand the experiments, we developed a model based on the thermodynamics of irreversible processes applied to the exchange of chemical species across a sharp solid/liquid interface. Parametrization of interfacial transfer coefficients enables the model to qualitatively reproduce the behaviors observed in the experiments. Finally, we sought to justify the kinetic parameters of the thermodynamic model using molecular dynamics (MD) in the Cu-Ni system. We thus demonstrated that the interfacial coefficients depend on the concentrations at the interface, consistent with the parametrization of the thermodynamic model
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Houchmandzadeh, Bahram. « Contribution à l'étude des transitions de phase dans les lignes et interfaces ». Grenoble 1, 1992. http://www.theses.fr/1992GRE10042.

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Dans ce travail, nous etudions certaines transitions de phase dans les lignes et interfaces. Le texte est concu en trois chapitres assez distincts. Dans le premier chapitre, les transitions de phase entre parois de bloch et ising dans un modele xy anisotrope sont etudiees. Nous generalisons la notion de parois de domaines aux systemes dynamiques ou une excitation parametrique joue le role de l'anisotropie. Le phenomene nouveau qui apparait alors est le mouvement des parois de bloch, avec une vitesse proportionnelle a leurs chiralites. Au deuxieme chapitre, nous etudions le role de la surface d'un cristal lors d'une transition de phase structurale, et nous comparons cette derniere a une transition de mouillage classique. Dans le cadre de notre modele, nous mettons en evidence une transition de phase de surface, comparable a une transition de premouillage, qui survient avant la transition de phase structurale du volume. Le troisieme chapitre etudie l'interaction entre deux chaines de polymeres, et la transition de localisation qui peut survenir dans ce systeme. Nous etudions plus particulierement la relation qui existe entre cette transition et l'enroulement mutuel des deux chaines. L'interaction entre les deux chaines qui a courte portee, peut comporter dans notre modele des termes qui favorisent l'enroulement
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Borges, Gomes Lima Yuri. « Μοdélisatiοn atοmistique de la transfοrmatiοn de phase austénite-ferrite dans les aciers ». Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMR086.

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Cette thèse applique l'approche des Quasiparticles (QA) pour étudier les mécanismes à l'échelle atomique qui conduisent à la transformation de phase CFC à CC dans le fer. Dans un premier temps, cette étude se concentre sur le fer pur, fournissant des résulats détaillés sur la nature et le rôle des dislocations à l'interface CFC-CC. Il a été montré que l'interface CFC-CC est semi-cohérente, avec des marches, et contient deux réseaux de dislocations de transformations. L'approche des Quasiparticles a permis de révéler l'influence de la relation d'orientation sur les caractéristiques de l'interface. Bien que les relations d'orientation étudiées ont montré diférentes structures d'interface, il a été démontré que toutes suivent le même chemin de transformation atomique, dû au glissement des dislocations de transformation à l'interface. Il a été conclu que la transformation complète de CFC à CC implique le mécanisme de transformation de Kurdjumov-Sachs (KS) en deux variantes le long des lignes de dislocations, avec le mécanisme de transformation de Kurdjumov-Sachs-Nishiyama (KSN) qui émerge comme la moyenne de l'action des deux mécanismes KS. Cette description détaillée a servi de base pour l'étude des systèmes Fe-C, où la ségrégation du carbone à l'interface a été observée. De plus, il a été montré que les profils de concentration de carbone sont cohérents avec des conditions d'équilibre local à l'interface
This thesis applies the Quasiparticle Approach (QA) to investigate the atomic scale mechanisms driving the phase transformation from FCC to BCC structures in iron. Initially, the study focuses on pure iron, providing detailed results into the nature and role of dislocations, at the FCC-BCC interface. It was shown that the FCC-BCC interface is semi-coherent and stepped, with two sets of transformations dislocations at the interface. The QA framework reveals how each orientation relationship (OR) influences the interface characteristics. Although the ORs displayed different interface structures, all were ultimately found to follow the same atomic transformation path, driven by the glide of transformation dislocations at the interface. It was concluded that the complete FCC to BCC phase transformation involves the action of the Kurdjumov-Sachs (KS) transformation mechanism in two variants along the two sets of dislocations, with the Kurdjumov-Sachs-Nishiyama (KSN) mechanism emerging as the average of the two KS mechanisms. This detailed description served as a basis for the study of Fe-C systems, where carbon segregation at the interface was observed. Moreover, it was shown that the carbon concentration profiles were consistent with local equilibrium conditions at the interface
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Muehlemann, Anton. « Variational models in martensitic phase transformations with applications to steels ». Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:bb7f4ff4-0911-4dad-bb23-ada904839d73.

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This thesis concerns the mathematical modelling of phase transformations with a special emphasis on martensitic phase transformations and their application to the modelling of steels. In Chapter 1, we develop a framework that determines the optimal transformation strain between any two Bravais lattices and use it to give a rigorous proof of a conjecture by E.C. Bain in 1924 on the optimality of the so-called Bain strain. In Chapter 2, we review the Ball-James model and related concepts. We present some simplification of existing results. In Chapter 3, we pose a conjecture for the explicit form of the quasiconvex hull of the three tetragonal wells, known as the three-well problem. We present a new approach to finding inner and outer bounds. In Chapter 4, we focus on highly compatible, so called self-accommodating, martensitic structures and present new results on their fine properties such as estimates on their minimum complexity and bounds on the relative proportion of each martensitic variant in them. In Chapter 5, we investigate the contrary situation when self-accommodating microstructures do not exist. We determine, whether in this situation, it is still energetically favourable to nucleate martensite within austenite. By constructing different types of inclusions, we find that the optimal shape of an inclusion is flat and thin which is in agreement with experimental observation. In Chapter 6, we introduce a mechanism that identifies transformation strains with orientation relationships. This mechanism allows us to develop a simpler, strain-based approach to phase transformation models in steels. One novelty of this approach is the derivation of an explicit dependence of the orientation relationships on the ratio of tetragonality of the product phase. In Chapter 7, we establish a correspondence between common phenomenological models for steels and the Ball-James model. This correspondence is then used to develop a new theory for the (5 5 7) lath transformation in low-carbon steels. Compared to existing theories, this new approach requires a significantly smaller number of input parameters. Furthermore, it predicts a microstructure morphology which differs from what is conventionally believed.
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López, Gabriel Alejandro. « Segregation and phase transformations at interfaces ». [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11380449.

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Bos, Cornelis. « Atomistic simulation of interface controlled solid state phase transformations ». [S.l. : s.n.], 2005. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-25279.

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Roland, Christopher. « Phase transitions of phospholipid monolayers on air-water interfaces ». Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66032.

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Perevoshchikova, Nataliya. « Modeling of austenite to ferrite transformation in steels ». Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0342/document.

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La thèse porte sur la modélisation de la transformation de l'austénite en ferrite dans les aciers en mettant l'accent sur les conditions thermodynamiques et cinétiques aux interfaces alpha/gamma en cours de croissance de la ferrite. Dans une première partie, la thèse se concentre sur la description des équilibres thermodynamiques entre alpha et gamma à l'aide de la méthode CalPhad. Nous avons développé un nouvel algorithme hybride combinant la construction d'une enveloppe convexe avec la méthode classique de Newton-Raphson. Nous montrons ses possibilités pour des aciers ternaire Fe-C-Cr et quaternaire Fe-C-Cr-Mo dans des cas particulièrement difficiles. Dans un second chapitre, un modèle à interface épaisse a été développé. Il permet de prédire l'ensemble du spectre des conditions à l'interface alpha/gamma au cours de la croissance de la ferrite, de l'équilibre complet au paraéquilibre avec des cas intermédiaires des plus intéressants. Nous montrons que de nombreux régimes cinétiques particuliers dans les systèmes Fe-C-X peuvent être prévus avec un minimum de paramètres d'ajustement, principalement le rapport entre les diffusivités de l'élément substitutionnel dans l'interface épaisse et dans le volume d'austénite. Le troisième chapitre porte sur l'étude d'un modèle de champ de phase. Une analyse approfondie des conditions à l'interface données par le modèle est réalisée en utilisant la technique des développements asymptotiques. En utilisant les connaissances fournies par cette analyse, le rôle de la mobilité intrinsèque d'interface sur la cinétique et les régimes de croissance est étudié, à la fois dans le cas simple d'alliages binaires Fe-C et dans le cas plus complexe d'alliages Fe-C-Mn
Transformation in steels focusing on the thermodynamic and kinetics conditions at the alpha/gamma interfaces during the ferrite growth. The first chapter deals with the determination of thermodynamic equilibria between alpha and gamma with CalPhad thermodynamic description. We have developed a new hybrid algorithm combining the construction of a convex hull to the more classical Newton-Raphson method to compute two phase equilibria in multicomponent alloys with two sublattices. Its capabilities are demonstrated on ternary Fe-C-Cr and quaternary Fe-C-Cr-Mo steels. In the second chapter, we present a thick interface model aiming to predict the whole spectrum of conditions at an alpha/gamma interface during ferrite growth, from full equilibrium to paraequilibrium with intermediate cases as the most interesting feature. The model, despite its numerous simplifying assumptions to facilitate its numerical implementation, allows to predict some peculiar kinetics in Fe-C-X systems with a minimum of fitting parameters, mainly the ratio between the diffusivities of the substitutional element inside the thick interface and in bulk austenite. The third chapter deals with the phase field model of austenite to ferrite transformation in steels. A thorough analysis on the conditions at the interface has been performed using the technique of matched asymptotic expansions. Special attention is given to clarify the role of the interface mobility on the growth regimes both in simple Fe-C alloys and in more complex Fe-C-Mn alloys
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Dong, Liang. « Interface morphology and its stability in martensitic phase transformation of NiTi shape memory alloy / ». View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?MECH%202008%20DONG.

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Livres sur le sujet "Phase transformation interfaces"

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A, Shafeev Georgy, dir. Phase transitions induced by short laser pulses. Hauppauge, NY : Nova Science Publishers, 2009.

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Alla, Oleinikova, et ScienceDirect (Online service), dir. Interfacial and confined water. Amsterdam : Elsevier, 2008.

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Japan) RIMS Conference "Far-From-Equilibrium Dynamics" (2011 Kyoto. Far-from-equilibrium dynamics : January 4-8, 2011. Kyoto, Japan : Research Institute for Mathematical Sciences, Kyoto University, 2012.

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S, El-Genk Mohamed, et United States. National Aeronautics and Space Administration., dir. "HPTAM", a two-dimensional heat pipe transient analysis model, including the startup from a frozen state : Final report no. UNM-ISNPS-4-1995. Albuquerque, N.M : Institute for Space and Nuclear Power Studies, School of Engineering, University of New Mexico, 1995.

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Micro- and nanostructured polymer blends : Phase morphology and interfaces. Boca Raton : Taylor & Francis, 2006.

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(Editor), John M. Ball, David Kinderlehrer (Editor), Paulo Podio-Guidugli (Editor), Marshall Slemrod (Editor) et E. Fried (Introduction), dir. Evolving Phase Interfaces in Solids : Fundamental Contributions to the Continuum Theory of Evolving Phase Interfaces in Solids. Springer, 1998.

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Harrats, Charef, Sabu Thomas et Gabriel Groeninckx. Micro- and Nanostructured Multiphase Polymer Blend Systems : Phase Morphology and Interfaces. Taylor & Francis Group, 2005.

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Harrats, Charef, Sabu Thomas et Gabriel Groeninckx. Micro- and Nanostructured Multiphase Polymer Blend Systems : Phase Morphology and Interfaces. Taylor & Francis Group, 2005.

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Micro- and nanostructured multiphase polymer blend systems : Phase morphology and interfaces. Boca Raton FL : CRC/Taylor & Francis, 2005.

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(Editor), Charef Harrats, Sabu Thomas (Editor) et Gabriel Groeninckx (Editor), dir. Micro- and Nanostructured Multiphase Polymer Blend Systems : Phase Morphology and Interfaces. CRC, 2005.

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Chapitres de livres sur le sujet "Phase transformation interfaces"

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Porter, D. A., et K. E. Easterling. « Crystal Interfaces and Microstructure ». Dans Phase Transformations in Metals and Alloys, 110–84. Boston, MA : Springer US, 1992. http://dx.doi.org/10.1007/978-1-4899-3051-4_3.

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Porter, David A., Kenneth E. Easterling et Mohamed Y. Sherif. « Crystal Interfaces and Microstructure ». Dans Phase Transformations in Metals and Alloys, 113–98. 4e éd. Boca Raton : CRC Press, 2021. http://dx.doi.org/10.1201/9781003011804-3.

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Willis, Roy F. « Surface Reconstruction Phase Transformations ». Dans Dynamical Phenomena at Surfaces, Interfaces and Superlattices, 126–47. Berlin, Heidelberg : Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-82535-4_15.

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Steinbach, Ingo, et Hesham Salama. « Stress–Strain and Fluid Flow ». Dans Lectures on Phase Field, 69–77. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-21171-3_7.

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AbstractIn this chapter first a multi-phase-field model considering transformation strain and elastic energy is developed. It utilizes the expansion into multiple phases of the multi-phase-field model. In particular, the treatment of the diffuse interface region as an effective medium is discussed in the context of homogenization theory. The model is applied to martensitic transformation within finite strain framework. In the second part of the lecture coupling for solute transport by melt flow is discussed. The model is applied to equiaxed dendritic solidification of MgAl in a shear flow.
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Paidar, Václav. « Elemental Interfaces and Displacive Phase Transformations ». Dans Advances in Science and Technology, 63–68. Stafa : Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/3-908158-16-8.63.

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Steinbach, Ingo, et Hesham Salama. « Concentration ». Dans Lectures on Phase Field, 49–59. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-21171-3_5.

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AbstractIn this chapter the coupling to solute concentration in an alloy is reviewed. During transformation the concentration between the phases must be redistributed, causing solute diffusion. First different approached to handle this problem are discussed comparatively. Special emphasis is given to the problem of scale in a mesoscopic phase field model. In detail the currently most advanced model, the so-called finite interface dissipation model is explained in detail. The chapter concludes with the discussion of the effect of multi-component diffusion and its handling in a phase-field model. As an example, solidification under additive manufacturing condition is presented with special emphasis of the microsegregation after solidification in a multi-component alloy.
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Blum, L., et Dale A. Huckaby. « A Phase Transition Induced by Water Reorientation at Electrode Interfaces ». Dans New Kinds of Phase Transitions : Transformations in Disordered Substances, 130–49. Dordrecht : Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0595-1_10.

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Rajendran, Mohan Kumar, Michael Budnitzki et Meinhard Kuna. « Multi-scale Modeling of Partially Stabilized Zirconia with Applications to TRIP-Matrix Composites ». Dans Austenitic TRIP/TWIP Steels and Steel-Zirconia Composites, 679–721. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-42603-3_21.

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Abstract The understanding of how the microstructure influences the mechanical response is an essential pre-requisite for materials tailored to match specific requirements. The aim of this chapter is to further this understanding in the context of Mg-PSZ-TRIP-steel composites on three different scales using a set of methods ranging from phase-field simulations over micromechanics to continuum constitutive modeling. On the microscale, using a Ginzburg-Landau type phase-field model the effects of cooling- and stress-induced martensitic phase transformation in MgO-PSZ is clearly distinguished. Additionally with this method the role of energy barrier in variant selection and the effect of residual stress contributing to the stability of the tetragonal phase are also investigated. On the mesomechanical scale, an analytical 2D model for the martensitic phase transformation and self-accommodation of inclusions within linear elastic materials has been successfully developed. The influences of particle size and geometry, chemical driving force, temperature and surface energy on the $$t \rightarrow m$$ t → m transformation are investigated in a thermostatic approach. On the continuum scale, a continuum material model for transformation plasticity in partially stabilized zirconia ceramics has been developed. Nonlinear hardening behavior, hysteresis and monoclinic phase fraction during a temperature cycle are analyzed. Finally, The mechanical properties of a TRIP steel matrix reinforced by ZrO$$_2$$ 2 particles are analyzed on representative volume elements. Here the mechanical properties of the composite as function of volume fraction of both constituents and the strength of the interface are studied.
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Acharya, D. P., E. Oshimura, K. Sakamoto et H. Kunieda. « The lyotropic ribbon phase and its transformation to the lamellar phase in the potassium N-dodecanoyl-dl-alaninate/water/decanol system ». Dans Trends in Colloid and Interface Science XVII, 25–29. Berlin, Heidelberg : Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/b93969.

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Gamsjäger, Ernst. « Kinetics of the Austenite-to-Ferrite Phase Transformation - From the Intrinsic to an Effective Interface Mobility ». Dans THERMEC 2006, 2570–75. Stafa : Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-428-6.2570.

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Actes de conférences sur le sujet "Phase transformation interfaces"

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Ye, Ming-Jyun, Satoshi Ishii et Kuo-Ping Chen. « Revisable Tuning of Tamm Plasmon Polaritons ». Dans JSAP-Optica Joint Symposia, 19a_P08_6. Washington, D.C. : Optica Publishing Group, 2024. https://doi.org/10.1364/jsapo.2024.19a_p08_6.

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Phase-change materials (PCMs) provide a specific combination of properties. The binary semiconducting chalcogenide Sb2S3 is consider one of the promising candidates, especially its intrinsic high refractive index, low loss and wide bandgap properties, in near infrared (NIR). Here, the Sb2S3 transformation from amorphous to crystal state embedded between the distribute Bragg reflector (DBR) and metal layer. At the interface between DBR and metal layer in specific parameter, Phase-change Tamm plasmon–polariton (PC-TPP) resonance could be produce. The PC-TPP resonance has a 70 nm modulation wavelength. Also, the resonance achieves around 100 nm-shifted in NIR at the proper incident angle.
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Hatakeyama, Tomotaka, Kota Sawada, Masaru Suzuki et Makoto Watanabe. « Microstructure of Modified 9Cr-1Mo Steel Manufactured via Laser Powder Bed Fusion ». Dans AM-EPRI 2024, 365–72. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.am-epri-2024p0365.

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Abstract Modified 9Cr-1Mo steel was manufactured via laser powder bed fusion (LPBF) using gas atomized powders under various building conditions. Dense samples were obtained at an energy density of 111-125 J/mm3. As-built samples were subjected to a normalization and tempering heat treatments. The microstructure of the as-built sample exhibits a duplex structure, comprising coarse columnar δ-ferrite grains and fine martensite grains. In addition, a small amount of retained austenite phase was observed at the interface between δ-ferrite and martensite. The formation of δ-ferrite is attributed to the extremely rapid solidification that occurs during the LPBF process, while martensite is obtained through the phase transformation because of the thermal cycles experienced during the process. The area fraction of δ-ferrite and martensite can be controlled by adjusting the LPBF parameters. Typical as-built microstructure morphology characterized by the columnar δ- ferrite was eliminated after the heat treatments, resulting in a tempered martensitic microstructure that is identical with that obtained through the conventional process. However, an increase in prior austenite grain size was observed when the area fraction of δ-ferrite in the as-built condition was high, due to faster phase transformation kinetics of martensite than that of δ-ferrite during the normalization. This suggests that the prior austenite grain size can be controlled by optimizing the area fraction of δ-ferrite and martensite in the as-built microstructure.
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Keblinski, Pawel, Samy Merabia, Jean-Louis Barrat, Sergei Shenogin et David G. Cahil. « Nanoscale Heat Transfer and Phase Transformation Surrounding Intensely Heated Nanoparticles ». Dans ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-13282.

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Using molecular dynamics simulations and theoretical analysis we study heat flow and phase behavior at the interface between high power-density, nanoscale heat sources and an embedding fluid medium. We show that the fluid next to the nanoparticle can be heated well above its boiling point without a phase change. Under increasing nanoparticle temperature, the heat flux saturates, which is in sharp contrast with the case of flat interfaces, where a critical heat flux is observed followed by development of a vapor layer and heat flux drop. These differences in heat transfer are explained by the curvature-induced pressure close to the nanoparticle, which inhibits boiling. We observe similar behavior for water, organic fluid, as well as generic model fluid underscoring generality of the results. We will also discuss the limits of the spatial and temporal localization of extreme temperature excursions and the limits to the applicability of the linear response theory to heat transfer at extremely large heat fluxes.
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Tsao, Wen-Huai, Rebecca Schurr et Christopher E. Kees. « High-Order Phase-Resolving Method for Wave Transformation Over Natural Shorelines ». Dans ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-104544.

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Abstract The use of nature-based facilities has become a popular solution to coastal hazard mitigation and shoreline stabilization. Emergent vegetation, such as mangrove forests, has been proven an effective protective system for alleviating wave and surge impact during a tsunami or tropical cyclone event. To reduce the quantification work and uncertain parameterized equations when modeling the wave height attenuation and momentum dissipation through emergent marsh vegetation, a new approach for implementing a high order Cut Finite Element Method (CutFEM) for problems with embedded solid structures in viscous incompressible flows is presented. The CutFEM allows using the same number of degrees of freedom as the underlying conforming Galerkin method on the fixed background mesh, which is independent of the configuration of non-conforming interfaces. Therefore, it has the same element assembly structure as classical FEM on the background mesh. No explicit generation of cut cell meshes, adaptive quadrature, or local refinement is required. The idea of equivalent polynomials is also adopted to compute the exact integration involving products of polynomials with Heaviside and Dirac distributions. Therefore, this method gains high-order accuracy for embedded interfaces and robustness of the signed distance representation in the level set field. The numerical method that uses a physical model of mock-up mangrove forests is validated through the wave flume experiment conducted by Kelty et al. at OSU. The correlations between the numerical results and experimental measurements are presented. All numerical simulations are completed by the open-source toolkit Proteus.
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Kumar, Parmod, Sushanta K. Mitra et Arup Kumar Das. « Towards the Understanding of Transformation of Annular to Droplet-Annular Gas-Liquid Flow ». Dans ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icnmm2016-7948.

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Annular flow and its deviations due to change of phase velocities in parallel and counter flows are very common in many adiabatic and non-adiabatic applications of two phase flow. The transformation from annular flow to its counterpart droplet-annular flow is often poorly understood as it needs to handle multi scale interfaces experimentally or numerically. In the present work, attempts have been made to capture both wavy annular interface and dynamics of tiny droplets throughout its life cycle using grid based volume of fluid framework. 3-D simulation domain with length (L)/diameter (D) ratio as 6 is considered under the effect of gravitational acceleration and phase inertial field. Wavy interface is observed numerically between the phases using phase fraction contours along with the occurrence of three very interesting phenomena, which include rolling, undercutting and orificing. At low liquid and gas velocities orificing has been observed which restricts the path of gaseous phase. Departure from the orificing phenomenon has been seen at higher gas phase velocities which transforms to other phenomenon called rolling. Rolling is the folding of liquid film by the high velocity gaseous phase towards the radially outward direction. Further, increase in liquid phase velocities above gaseous phase velocities results in undercutting of liquid film by the gas phase. Moreover the liquid droplets can be seen in the entire phenomenon through the gas phase in the core of the tube. We presented a regime map of gas liquid velocities to segregate clear understanding of annular to droplet-annular flow due to orificing, rolling and undercutting. The present study will enrich the knowledge of multiphase flow transportation in process plants, chemical reactors, nuclear reactors and refineries where gas-liquid annular flow is most widely used flow pattern.
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Jung, Kwangsub, Maenghyo Cho et Min Zhou. « Thermomechanical Behavior of GaN Nanowires During Tensile Loading and Unloading ». Dans ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75144.

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Structural phase transformations from wurtzite to a graphite-like phase and from wurzite to a tetragonal phase in ZnO and GaN nanowires under tensile loading cause significant changes in thermal conductivity. Molecular dynamics simulations are carried out to investigate the effect of deformation and the phase transformations on the thermal conductivity of [0001]-oriented GaN nanowires. The calculation of conductivity at each state of the nanowires is based on the equilibrium Green-Kubo approach with quantum correction. Under tensile loading, initially wurtzite-structured wires transform into a tetragonal structure, causing the thermal conductivity to decrease as the strain increases. Unloading of the transformed wires is associated with a reverse transformation from the tetragonal structure to the wurtzite structure. Opposite to what is observed during the forward transformation during loading, the thermal conductivity increases as the strain decreases in the unloading process. However, during the reverse transformation, the nanowires consist of both tetragonal regions and wurtzite-structured regions. Such intermediate states are not observed during the loading process. Phonon scattering at the interfaces between the wurtzite and tetragonal regions during unloading causes the thermal conductivity of the nanowires to be lower compared with that during loading.
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Pershin, Yu P., E. A. Bugaev, I. A. Kopilets, S. A. Yulin et I. V. Kozhevnikov. « ATTAINMENT OF PHASE EQUILBRIUM IN MULTILAYERS ». Dans Physics of X-Ray Multilayer Structures. Washington, D.C. : Optica Publishing Group, 1994. http://dx.doi.org/10.1364/pxrayms.1994.wa.4.

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Structural, phase and chemical stabilities of multilayers Mo-Si, MOSi2- Si, W-Si, WSi2-Si, Cr-Sc, W-Sc, Mo-B4C, Mo−(B+C), Mo2B5-B4C, Cr3C2-C, TiC-C, Ti-Be and others were studied in 300-1100°C temperature range by small-angle and large-angle X-ray diffraction scattering and electron microscopy methods. The structural instability (crystallization of amorphous Si, C, MOSi2, WSi2, MoC, MoB2, Mo2B5, B and Cr3 C2 and recrystal-lization of polycrystal Mo, W, Sc, MoSi2, WSi2, Mo2B5 and MoC layers) as well as the phase instability (transformation of MoSi2 lattice from hexagonal to tetragonal modification) are responsible for the degradation of multilayers due to the development of the interface roughness and mechanical stresses. The chemical instability (formation of MoSi2 and WSi2 silicides at interfaces of Mo-Si and W-Si multilayers, Mo2C and MoC carbides and MoB2 and Mo2B5 borides in Mo-(B+C) multilayers, TiBe12 in Ti-Be ones) influences critically chemical composition profile, layer thicknesses and a period of multilayers. Formation of chemical compounds accompanied by an amorphization of polycrystal layers (growth of amorphous Mo2C and MoC carbides instead of polycrystal Mo at about 450 °C and the subsequent substitution of polycrystal molybdenum carbides on amorphous borides MoB2 and Mo2B5 at 700-800 °C in Mo-(B+C) multilayers) promotes the smoothening of interfaces. This effect of the chemical instability can be used for an improving of the X-ray reflectivity of multilayers.
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Toloui, Morteza, et Matthias Militzer. « Phase Field Modelling of Microstructure Evolution in the HAZ of X80 Linepipe Steel ». Dans 2012 9th International Pipeline Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ipc2012-90378.

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The heat affected zone (HAZ) during welding experiences a very steep temperature gradient which results in significant microstructure gradients. Thus, model approaches on the length scale of the microstructure, i.e. the so-called mesoscale, are useful to accurately simulate microstructure evolution in the HAZ. In this study, a phase field model (PFM) is employed to simulate austenite grain growth and austenite decomposition in the HAZ of an X80 linepipe steel microalloyed with Nb and Ti. The interfacial mobilities and nucleation conditions are obtained by benchmarking the PFM with experimental data from austenite grain growth and continuous cooling transformation tests. An effective grain boundary mobility is introduced for austenite grain growth to implicitly account for dissolution of NbC. Subsequently, austenite decomposition into polygonal ferrite and bainite is considered. For this purpose the PFM is coupled with a carbon diffusion model. Ferrite nuclei are introduced at austenite grain boundaries and suitable interfacial mobilities are selected to reproduce experimental ferrite formation kinetics. Bainite nucleation occurs for a sufficiently high undercooling at available interface sites (i.e. austenite grain boundaries and/or austenite-ferrite interfaces). For simplicity, the formation of carbide-free bainite is considered and a suitable anisotropy approach is proposed for the austenite-bainite interface mobility. The model is then used to predict austenite grain growth and phase transformation in the HAZ.
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Perez, Celeste, Ashley N. Bucsek et Adam Creuziger. « In-Situ Characterization of Phase Interfaces in CuAlNi during Mechanical Cycling Using Dark-Field X-Ray Microscopy ». Dans SMST 2024. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.smst2024p0031.

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Abstract Interfacial stress fields play a critical role governing the hysteresis and functional fatigue of shape memory alloys. These stress fields manifest at austenite-martensite interfaces (i.e., habit planes) as a consequence of geometric incompatibility between the austenite and martensite phases. As the material approaches transformation, these interfacial stress fields act as an energy barrier, requiring extra energy to be driven into the system to overcome it, resulting in a hysteresis. In addition, increasing the energy in the system also increases dislocation generation, resulting in functional fatigue. In this research, we employ dark-field X-ray microscopy (DFXM), a high-resolution diffraction microstructure imaging technique, to characterize austenite-martensite interfaces and interfacial stress fields during mechanical cycling in a CuAlNi shape memory alloy. The results show, in 3D, the emergence and evolution of individual austenite-martensite interfaces and spatially mapped orientation and elastic strain, including the interfacial elastic strain fields at austenite-martensite interfaces. These findings will contribute to a better understanding of the origins of hysteresis and functional fatigue by investigating interfacial stress fields and dislocation generation at phase interfaces and their effects on macroscopic behavior.
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Srinivas, Mullahalli V., et George J. Dvorak. « Energy Released by Interfacial Decohesion in a Two-Phase Composite System ». Dans ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0356.

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Abstract Under service loads or during fabrication and processing, certain fibrous composite plies may experience extensive decohesion, such as debonding and sliding at fiber-matrix interfaces. The effect of some of these damage processes on overall stiffness and on internal stress redistribution is analyzed here with the Transformation Field Analysis method (Dvorak and Benveniste, 1992, Proc. R. Soc., London, Vol. A437, p. 291), which simulates creation of new internal surfaces by equivalent eigenstrains applied to an undamaged elastic system. Simple expressions for change in potential energy of the damaged ply are also obtained using the Colonetti’s theorem. The analytical results are shown to be in good agreement with selected finite element solutions for unit cells. Applications indicate that the energy released by fiber debonding depends linearly on fiber radius.
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