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Lattice Monte Carlo simulation results showing the predicted nanocluster (NC) structure, size (precipitate radius, r ppt ), composition, and calculated magnetic/nuclear (M/N) scattering ratio (a) as a function of NC lattice parameter relative to a reference value a (e.g., 1.0a, 1.1a) in an Fe-0.47at.%Ti-0.12at.%Y-0.19at.%O alloy at 0°C and (b) as a function of alloy oxygen content in an Fe-0.47at.%Ti-0.12at.%Y alloy at 400°C and a NC lattice parameter of 1.3a. 59 Note the different size scale for the simulation with a NC lattice parameter of 1.1a, where Y-Ti-O nanoclusters did not form, but rather individual TiO and Y clusters continually formed and dissolved.
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Designing structural materials for tailored response at extreme conditions is a grand challenge in materials research. Such materials can be made using either "top-down" or "bottom-up" processes to create nanostructured metals and composites that contain atomically designed interfaces that not only block dislocation slip but also attract, absorb, a...
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... Understanding the origins of nanolaminate strength involves studying these mobile defects under stress and their interactions with the biphase interface. Also, a variety of synthesis methods, such as deposition, thermomechanical processing, bulk metal formation, and thin film deposition, are available for fabricating metal/metal nanolaminates due to their entirely metallic character (1,(9)(10)(11)(12). ...
... The two types of {111}Cu||{111}Ag interfaces shown in Figure 2d,e, for instance, can coexist in the same nanolaminate material since they have similarly low interfacial energies (25,26). Likewise, for fcc/bcc nanolaminate systems, the two most commonly occurring interface orientation relationships are KS and NW (9), and Cu/Nb-deposited films contain both equally. In the film shown in Figure 2f,g, the KS and NW interface planes correspond to densely packed fcc {111} and bcc {110} planes, resulting in an atomically flat interface. ...
This article reviews recent basic research on two categories of metal-based nanolaminates: those composed of metal/metal constituents and those composed of metal/ceramic constituents. We focus primarily on studies that aim to understand—via experiments, modeling, or both—the biphase interface structure and its role in changing the mechanisms that govern strength and deformability at a fundamental level. We anticipate that, by providing a broad perspective on the latest advances in nanolaminates, this review will aid design of new metallic materials with unprecedented combinations of mechanical and physical properties.
... Mechanically stronger electrically conducting wires are required in various domains such as record (100 T) pulsed magnetic fields, power and aerospace engineering. The requirements on electrical conductivity impose a material with a composition as close as possible to pure copper (Cu), therefore ruling out using metallic alloys [1]. Earlier studies have shown that nanocomposite Cu-matrix wires designed and prepared with a combination of ultrafine microstructure and one-dimensional (1D) reinforcement, such as carbon nanotubes (CNT) [2,3] and silver nanowires (Ag NW) [4], show both a high ultimate tensile strength (UTS) and a low electrical resistivity. ...
Composite powders made up of 1 vol. %Ag nanowires (NW) dispersed in Cu were prepared and consolidated into cylinders by spark plasma sintering. One cylinder was sintered at only 400 °C resulting in a nanocomposite sample with no dissolution of the Ag NW into the Cu matrix. The second cylinder was sintered at 600 °C and the Ag NW are dissolved forming Ag/Cu alloy NW. The cylinders served as starting materials for room temperature wire-drawing, enabling the preparation of wires of decreasing diameters. The microstructure of the cylinders and the wires was investigated by electron microscopy and associated techniques. The tensile strength and electrical resistivity were measured at 293 K and 77 K. The nanocomposite and alloy wires show similar UTS values (1100 MPa at 77 K), but alloying, although spatially limited, provoked a significant increase in electrical resistivity (0.56 µΩ cm at 77 K) compared to the nanocomposite wires (0.49 µΩ cm at 77 K).
Graphical abstract
... La bobine intérieure est bobinée avec du fil nano-composite filamentaire cuivre-niobium (Cu-Nb) produit par la start-up russe NanoElectro, fondée par des chercheurs du Bochvar Institute de Moscow ( Fig. I.5). C'est actuellement l'un des conducteurs les plus résistants mécaniquement qu'il est possible de se procurer de façon commerciale [19,20]. ...
... Après tréfilage, les dendrites se sont affinées pour former des rubans orientés dans le sens de la déformation ( Fig. I.20). Les fibres de niobium sont réparties de façon contrôlée dans la matrice de cuivre [15,19,66,[81][82][83]. Il existe différents types de géométrie selon la conception de la billette initiale : filamentaire (Cu-Nb) [37,88], co-cylindrique (Cu-Nb-Cu) [81] et co-axiale (Cu-Nb-Cu-Nb) [83]. ...
... Le tréfilage permet de mettre en forme des métaux en les déformant plastiquement. Lorsque le taux de déformation vraie η appliqué au fil est supérieur à 5, on considère le procédé d'étirage comme une technique de déformation plastique sévère [19]. Afin de réduire sa section, le fil est étiré à travers une filière présentant un angle de travail α (Fig. II.18). ...
Le LNCMI-Toulouse produit les champs magnétiques non-destructifs pulsés parmi les plus puissants du monde (98,8 T). Les fils conducteurs utilisés dans les bobines qui génèrent ces champs magnétiques nécessitent une contrainte à la rupture élevée afin de résister aux forces de Lorentz. De plus, pour obtenir une durée d'impulsion la plus longue possible, ces conducteurs doivent avoir une résistivité électrique la plus proche possible de celle du Cu pur. Le LNCMI et le CIRIMAT explorent la conception et la préparation de fils nano-composites à matrice Cu par une combinaison de métallurgie des poudres, de frittage SPS et de tréfilage. Les poudres composites à faibles teneurs en Ag (< 10 % vol. Ag) sont préparées en dispersant des microfils d'Ag (diamètre 200 nm, longueur 30 µm) synthétisés au CIRIMAT dans une poudre commerciale de Cu sphérique (diamètre 0,5-1 µm). Les poudres ainsi obtenues sont consolidées par SPS sous forme de barreaux. Ceux-ci sont étirés sans rupture, jusqu'à l'obtention de fils fins (diamètre 1 - 0,2 mm) dont la microstructure est sous la forme de grains ultrafins de Cu (200 - 400 nm) allongés sur plusieurs micromètres dans le sens de l'étirage. Les microfils d'Ag sont dispersés le long des joints de grains du Cu. La mesure de la résistivité électrique et de la contrainte à la rupture des fils (à 293 K et 77 K) a permis de déterminer que les fils contenants seulement 1 % vol. Ag présentent le meilleur compromis contrainte à la rupture / résistivité (1100 MPa / 0,49 µÔmega.cm à 77 K). La formation d'un alliage Cu/Ag lors du frittage SPS a pour conséquence une augmentation notable de la résistivité électrique des fils et doit donc être évitée. Une matrice de Cu avec une distribution bimodale de la taille des grains permet de réduire la résistivité électrique tout en conservant une haute contrainte à la rupture (1080 MPa / 0,45 µÔmega.cm à 77 K). Les fils nano-composites Ag-Cu présentent une contrainte à la rupture équivalente à celle des fils d'alliage Cu/Ag contenant environ 20 fois plus d'Ag élaborés par fusion et solidification, mais présentent une résistivité électrique environ 1,5 fois plus faible.
... Most studies relate the high strength to the microstructures refinement and the crystal structures difference between Cu and Nb in Cu-Nb alloy [89,90]. Moreover, some references [91,92] stated that both the strength and conductivity were strongly dependent on the Nb content, while others [90,93,94] suggested that the spacing between filaments or interfaces dominated the strength. ...
High strength and high conductivity (HSHC) Cu alloys are widely used in many fields, such as high-speed electric railway contact wires and integrated circuit lead frames. Pure Cu is well known to have excellent electrical conductivity but rather low strength. The main concern of HSHC Cu alloys is how to strengthen the alloy efficiently. However, when the Cu alloys are strengthened by a certain method, their electrical conductivity will inevitably decrease to a certain extent. This review introduces the strengthening methods of HSHC Cu alloys. Then the research progress of some typical HSHC Cu alloys such as Cu-Cr-Zr, Cu-Ni-Si, Cu-Ag, Cu-Mg is reviewed according to different alloy systems. Finally, the development trend of HSHC Cu alloys is forecasted. It is pointed out that precipitation and micro-alloying are effective ways to improve the performance of HSHC Cu alloys. At the same time, the production of HSHC Cu alloys also needs to comply with the large-scale, low-cost development trend of industrialization in the future.
... In recent years, two types of filamentary and multilayered nano-composites composed of copper and niobium (i.e. Cu-Nb nano-composite wires and laminates) have been highlighted thanks to their special properties (Misra and Thilly, 2010). These two Cu-Nb nano-composites are fabricated respectively by two different severe plastic deformation techniques: Accumulative Drawing and Bundling (Dupouy et al., 1996;5 Thilly, 2000;Vidal, 2006;Dubois, 2010;Medy, 2016) and Accumulated Roll Bonding (Lim and Rollett, 2009;Beyerlein et al., 2014). ...
Nanostructured and architectured copper niobium composite wires are excellent candidates for the generation of intense pulsed magnetic fields (~100T) as they combine both high strength and high electrical
conductivity. Multi-scaled Cu-Nb wires are fabricated by accumulative drawing and bundling (a severe plastic deformation technique), leading to a multiscale, architectured, and nanostructured microstructure exhibiting a strong fiber crystallographic texture and elongated grain shape along the wire axis. This paper presents a comprehensive study of the effective elasto-plastic behavior of this composite material by using two different approaches to model the microstructural features: full-field finite elements and mean-field modeling. As the material exhibits several characteristic scales, an original hierarchical strategy is proposed based on iterative scale transition steps from the nanometric grain scale to the millimetric macro-scale. The best modeling strategy is selected to estimate reliably the effective elasto-plastic behavior of Cu-Nb wires
with minimum computational time. Finally, for the first time, the models are confronted to tensile tests and in-situ neutron diffraction experimental data with a good agreement.
... 71 3.5 Contrainteà limiteélastique σ c (GPa), et déformationà limiteélastique ε c (%)en fonction du diamètre D des nanoparticules d'aluminium, orientée <010>. ... 73 3.6 Schéma de l'évolution de la limite d'élasticité σ y dans les métaux en fonction de la taille des microstructures (Figure issue de [Misra et Thilly, 2010]). . . . . 74 3.7 Variation de contrainte limiteélastique σ c en fonction du diamètre D des nanoparticules d'aluminium, orientée <010>. . . . . . . . . . . . . . . . . . . . . ...
Lorsque leurs dimensions deviennent nanométriques, les matériaux présentent généralement des propriétés bien différentes de celles mesurées aux échelles supérieures. Ainsi, concernant les propriétés mécaniques, il est, par exemple, souvent fait état d’une résistance accrue à la déformation plastique. Toutefois, une majorité des travaux dans ce domaine concerne des systèmes à une dimension, tels que les nanofils et les nanopiliers. Nos connaissances des propriétés mécaniques d’un autre type de système ’nano’, à savoir les nanoparticules, restent actuellement limitées, ce qui est surprenant en regard de leur immense champ d’applications.Les travaux ici présentés portent sur les propriétés mécaniques de nanoparticules sphériques de matériaux métalliques de structure cubique à faces centrées (aluminium, nickel, cuivre). Ils ont été conduits à l’aide de simulations de dynamique moléculaire de compression uniaxiale.Ces dernières permettent d’analyser finement les mécanismes de plasticité à l’échelle atomique.Deux axes principaux d’étude ont été retenus : l’influence de la taille des nanoparticules et géométrie de la surface de contact dans la gamme de taille étudiée (4-80 nm) lors des premiers stades de déformation plastique. Nous montrons ainsi que cette dernière influe sur la limite d’élasticité, ainsi que sur le mode de déformation plastique, tel que le maclage.
... In recent years, two types of filamentary and multilayered nano-composites composed of copper and niobium (i.e. Cu-Nb nano-composite wires and laminates) have been highlighted for their their special properties [1]. These Cu-Nb nano-composites were fabricated by two different severe plastic deformation 5 techniques: Accumulative Drawing and Bundling (i.e. ...
... At scale H2 ( Fig. 1(b)(e)), the effective long fibers consists of two layers: (1) the nano-composite Cu-Nb zones containing 85 1 parallel elementary fibers (i.e. is given by the effective tensor ( σ ∼ ) H1 at H1. On the other hand, (σ ∼ (2) ) H2 of the second layer for H2 is associated with the conductivity of Cu-1 (σ ∼ ) Cu-1 . The scale transition is then performed by GSC and PH approaches, leading to the effective conductivity ( σ ∼ ) H2 for the assembly of 85 2 elementary long fibers. ...
Nanostructured and architectured copper niobium composite wires are excellent candidates for the generation
of intense pulsed magnetic fields (> 90T) as they combine both high electrical conductivity and high strength.
Multi-scaled Cu-Nb wires can be fabricated by accumulative drawing and bundling (a severe plastic deformation technique), leading to a multiscale, architectured and nanostructured microstructure providing a unique set of properties. This work presents a comprehensive multiscale study to predict the anisotropic effective electrical conductivity based on material nanostructure and architecture. Two homogenization methods are applied: a mean-field theory and a full-field approach. The size effect associated with the microstructure refinement is taken into account in the definition of the conductivity of each component in the composites. The multiscale character of the material is then accounted for through an iterative process. Both methods show excellent agreement with each other. The results are further compared, for the first time, with experimental data obtained by the four-point probe technique, and also show excellent agreement. Finally, the qualitative and quantitative understanding provided by these models demonstrates that the microstructure of Cu-Nb wires has a significant effect on the electrical conductivity.
... Two types of filamentary and multilayered nano-composites composed of copper and niobium (i.e. Cu-Nb nano-composite wires and laminates) have been highlighted among them (Misra and Thilly, 2010). These two Cu-Nb nano-composites are fabricated respectively by two different severe plastic deformation techniques: Accumulative Drawing and Bundling (i.e. ...
... Au cours des dernières années, il y a eu une demande croissante pour la génération de nouveaux nano-matériaux architecturés présentant une résistance, une conductivité electrique, une dureté, une ductilité, une stabilité thermique et une tolérance aux rayonnements extraordinairementélevées. Deux types de nano-composites filamentaires ou multicouches composés de cuivre et de niobium offrent des propriétés intéressantes (Misra and Thilly, 2010). Ces deux nano-composites Cu-Nb sont fabriqués respectivement par deux techniques différentes de déformation plastique sévère : "Accumulative Drawing and Bundling" (ADB, voir la description détaillée dans Section 2.1 ou Vital (2006)) et "Accumulated Roll Bonding" (Lim and Rollett, 2009;Beyerlein et al., 2014). ...
Les fils composites nanostructurés et architecturés cuivre-niobium sont de candidats excellents pour la génération de champs magnétiques intenses (>90T); en effet, ces fils allient une limite élastique élevée et une excellente conductivité électrique. Les fils Cu-Nb multi-échelles sont fabriqués par étirage et empaquetage cumulatif (une technique de déformation plastique sévère), conduisant à une microstructure multi-échelle, architecturée et nanostructurée présentant une texture cristallographique de fibres forte et des formes de grains allongées le long de l'axe du fil. Cette thèse présente une étude compréhensive du comportement électrique et élasto-plastique de ce matériau composite, elle est divisée en trois parties: modélisation multi-échelle électrique, élastique et élasto-plastique. Afin d'étudier le lien entre le comportement effective et la microstructure du fil, plusieurs méthodes d'homogénéisation sont appliquées, qui peuvent être séparées en deux types principaux: la méthode en champs moyens et en champs complets. Comme les spécimens présentent plusieurs échelles caractéristiques, plusieurs étapes de transition d'échelle sont effectuées itérativement de l'échelle de grain à la macro-échelle. L'accord général parmi les réponses de modèle permet de suggérer la meilleure stratégie pour estimer de manière fiable le comportement électrique et élasto-plastique des fils Cu-Nb et économiser le temps de calcul. Enfin, les modèles électriques prouvent bien prédire les données expérimentales anisotopique. De plus, les modèles mécaniques sont aussi validés par les données expérimentales ex-situ et in-situ de diffraction des rayons X/neutrons avec un bon accord.
... Two types of filamented and multilayered nano-composites composed of copper and niobium (i.e. Cu-Nb nano-composite wires and laminates) are highlighted among them (Misra and Thilly, 2010). These two Cu-Nb nano-composites are fabricated respectively by two different severe plastic deformation techniques: Accumulative Drawing and Bundling (i.e. ...
Nanostructured and architectured copper niobium composite wires are excellent candidates for the generation of intense pulsed magnetic fields ($>$90T) as they combine both high strength and high electrical conductivity. Multi-scaled Cu-Nb wires are fabricated by accumulative drawing and bundling (a severe plastic deformation technique), leading to a multiscale, architectured, and nanostructured microstructure exhibiting a strong fiber crystallographic texture and elongated grain shapes along the wire axis. This paper presents a comprehensive study of the effective elastic behavior of this composite material by three multi-scale models accounting for different microstructural contents: two mean-field models and a full-field finite element model. As the specimens exhibit many characteristic scales, several scale transition steps are carried out iteratively from the grain scale to the macro-scale. The general agreement among the model responses allows suggesting the best strategy to estimate the effective behavior of Cu-Nb wires and save computational time. The importance of crystallographical and morphological textures in various cases is discussed. Finally, the models are validated by available experimental data with a good agreement.
... Both experimental and modeling studies show GBs generally act as sinks for the point defects produced from irradiation (Beyerlein et al., 2015;Dollar and Gleiter, 1985;Gleiter, 1979;Han et al., 2012;King and Smith, 1980;Siegel et al., 1980). Thus, GB may impart irradiation resistance properties to polycrystalline materials (Han et al., 2013;Misra et al., 2007;Misra and Thilly, 2010). For this reason, understanding the point defect sink efficiency of GBs is of great importance for the design of materials with irradiation resistance and understanding the properties of such materials (Li et al., 2012;Misra and Thilly, 2010;Singh and Zinkle, 1993;Xiao et al., 2015a,b). ...
... Thus, GB may impart irradiation resistance properties to polycrystalline materials (Han et al., 2013;Misra et al., 2007;Misra and Thilly, 2010). For this reason, understanding the point defect sink efficiency of GBs is of great importance for the design of materials with irradiation resistance and understanding the properties of such materials (Li et al., 2012;Misra and Thilly, 2010;Singh and Zinkle, 1993;Xiao et al., 2015a,b). Extensive studies have been carried out to understand the possible factors that determine the sink efficiency of GBs (Demkowicz et al., 2011b;King and Smith, 1981;Millett et al., 2009;Zhang et al., 2012). ...
Grain boundaries (GBs) in the polycrystalline and nanocrystalline materials are usually at their non-equilibrated states due to the plastic deformations. Thus, the point defect sink efficiencies of non-equilibrated GBs may be different from those of equilibrated counterparts, which may influence the irradiation tolerance of materials. In this paper, we firstly performed the shear responses of four copper symmetric tilt grain boundaries (GBs). The plastic deformation modes of four GBs include GB sliding, shear-coupling and complex mechanism due to atom-shuffling, partial dislocation nucleation and local GB dissociations. We then study the energetics of point defects interacting with a series of GB configurations undergone plastic deformations. It is found that the plastic deformation dominated by the sliding and shear-coupling has no effect on the point defect sink efficiency of GB in comparison with initial GB states. However, sink efficiencies of GB configurations produced from the complex deformation mode are generally intensified, for both vacancy and self-interstitial atom. In addition, the residual stress in the crystals due to the dislocation nucleating from GB affects the point defect concentration in the crystals. On the other hand, complex deformation mechanism drives GBs to higher energy states with highly disordered structures. As a result, the distribution of lower point defect formation energies extends a larger distance from GB, which may therefore favor GB absorbing the point defects nearby.
