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Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Domaines magnétiques, courbes d'aimantation et hystérésis, Domain effects, magnetization curves, and hysteresis, Courbes d'aimantation, inversion d'aimantation, hystérésis, effet barkhausen et phénomènes associés, Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects, Résonances et relaxations magnétiques dans l'état condensé, effet mössbauer, Magnetic resonances and relaxations in condensed matter, mössbauer effect, Effet mössbauer; autres spectroscopies par rayons γ, Mössbauer effect; other γ-ray spectroscopy, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Poudres métalliques, Metal powders, Aimantation saturation, Saturation magnetization, Imanación saturación, Aimantation, Magnetization, Broyeur boulet, Ball mill, Molino bolas, Kugelmuehle, Chrome alliage, Chromium alloys, Contrainte interne, Internal stresses, Diffraction RX, XRD, Effet Mössbauer, Moessbauer effect, Fer alliage, Iron alloys, Microscopie électronique balayage, Scanning electron microscopy, Microstructure, Métal transition alliage, Transition element alloys, Métallurgie poudre, Powder metallurgy, Perméabilité magnétique, Magnetic permeability, Silicium alliage, Silicon alloys, Ball-milling, Fe-Si-Cr, Flake, and Mössbauer

Flake-shaped particles were fabricated from crushing ingots with ball milling method. Scanning electron microscope (SEM), X-ray diffraction (XRD), vibrating samples magnetometer (VSM) and Mössbauer spectroscopy measurements were carried out to characterize the milled powders. The XRD results show that the DO3 ordered phase coexists with α-Fe(Si,Cr) matrix phase. Generally, grain size decreases with milling time, as internal strain increases. The fitting result of the Mössbauer spectra of the as-prepared powders reveals that the DO3 phase always exists, but the percentage of DO3 phase drops from 52% in the starting powder to 25% after 80 h milling. A planar anisotropy of the flake-shaped powders is also demonstrated by the Mössbauer spectra, and found to increase with milling time. The saturation magnetization M5 has a maximum value of 109 emu/g after milling of 8 h, and then remains at a steady value around 104 emu/g. The maximum complex permeability is obtained by 32 h milling.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des solides, Mechanical properties of solids, Déformation et plasticité (incluant limite élastique, ductilité et superplasticité), Deformation and plasticity (including yield, ductility, and superplasticity), Bande cisaillement, Shear band, Banda cizallamiento, Cuivre alliage, Copper alloys, Déformation dent de scie, Serrated yielding, Déplacement déformation, Displacement(deformation), Desplazamiento deformación, Ecoulement plastique, Plastic flow, Microstructure, Métal transition alliage, Transition element alloys, Nanoindentation, Nanoindentacion, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Verre métallique, Metallic glasses, Volume libre, Free volume, Volumen libre, Zirconium alliage, Zirconium alloys, Bulk metallic glass, Serrated flow, and Structural inhomogeneity

The local mechanical properties and the serrated flow behavior of a Cu36Zr48AlsAg8 bulk metallic glass (BMG) have been investigated using nanoindentation. The influence of structural inhomogeneity on the deformation behavior of the BMG is confirmed. The loading rate plays little role in the deviation degree of load-displacement (P-h) curves. It was found that the accumulation of different kinds of serrations leads to the deviation of the P-h curves under a low loading rate. The deviation degree is associated with the numbers and characteristics of the serrated flow. Under a high loading rate, the simultaneous operation of multiple shear bands leads to the disappearance of the serrated flows, and the deviation degree of the P-h curves with each other is assumed to be related to the accumulation of different inconspicuous serrated flows.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Solubilité, ségrégation, mélanges et séparation de phases, Solubility, segregation, and mixing; phase separation, Chlorure de lithium, Lithium chloride, Litio cloruro, Chlorure de potassium, Potassium chloride, Potasio cloruro, Effet concentration, Quantity ratio, Etat fondu, Melts, Solubilité, Solubility, Titane, Titanium, Equilibrium constant, LiCl-KCI melts, and Titanium ions

The equilibrium between metallic titanium and titanium ions (Ti2+, Ti3+) dissolved in LiCI-KCl melts and the influence of the electrolyte composition on the equilibrium were investigated. The accurate concentrations of titanium ions had been obtained based on a reliable approach for taking samples. Furthermore, accurate values of the equilibrium constants were calculated by the best-fitting method under the consideration of the TiOCl dissolution. The influence of the electrolyte composition on the equilibrium was evaluated by determining the equilibrium constant Kc between titanium metal and titanium ions in LiCl- KCl melts with different concentration of LiCl. It was shown that LiCl could affect the equilibrium and the Kc values decreased with the increase of concentration of LiCl.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Structure électronique des nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals, Emissions électronique et ionique; phénomènes d'impact, Electron and ion emission by liquids and solids; impact phenomena, Emission, ionisation, évaporation et désorption de champ, Field emission, ionization, evaporation, and desorption, Addition phosphore, Phosphorus additions, Centre donneur, Donor center, Centro dador, Emission électronique champ, Electron field emission, Etat impureté, Impurity states, Liaison covalente, Covalent bonds, Liaison ionique, Ionic bonds, Méthode fonctionnelle densité, Density functional method, Méthode pseudopotentiel, Pseudopotential methods, Nanofil, Nanowires, Nitrure de gallium, Gallium nitride, Galio nitruro, Paramètre cristallin, Lattice parameters, Structure électronique, Electronic structure, GaN, Electronic properties, First principles, and P-doped GaN nanowires

The electronic properties of phosphorus-doped unsaturated and saturated gallium nitride (GaN) nanowires have been investigated from first-principles using the ultrasoft pseudopotential method. The results of these calculations indicate that the P impurities are enriched at the surface of gallium nitride nanowires, and that the structural symmetry of GaN nanowires is broken due to changes in the lattice parameters. When the P impurity substitutes for the Ga atom, the width of band gap increases at the Γ point, a donor impurity level appears in the band gap, and the P impurity and adjacent N atoms exists covalent interaction. Moreover, when the P impurity substitutes for the N atom, the width of the band gap decreases slightly at the Γ point, there is no obvious impurity level in the band gap, and P-Ga covalent bonds are formed, including those composed of ionic bonds. These conclusions indicate that the incorporation of P impurities can improve the field emission performance of GaN nanowires, which is consistent with the experimental results.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Frottement. Usure, Contact of materials. Friction. Wear, Coulée centrifuge, Centrifugal casting, Colada centrífuga, Schleudergiessen, Diagramme phase, Phase diagram, Diagrama fase, Phasendiagramm, Durcissement précipitation, Precipitation hardening, Endurecimiento precipitación, Ausscheidungshaerten, Elément alliage, Alloying element, Elemento aleación, Legierungselement, Essai usure, Wear test, Prueba al desgaste, Verschleissversuch, Fraction volumique, Volume fraction, Fracción volumétrica, Haute température, High temperature, Alta temperatura, Hochtemperatur, Laminage, Rolling, Laminado, Walzen, Microstructure, Microestructura, Mikrogefuege, Métal transition alliage, Transition metal alloy, Metal transición aleación, Uebergangsmetallegierung, Nickel alliage, Nickel alloy, Níquel aleación, Nickellegierung, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Composition fluctuations, Metals and alloys, Phase diagrams, Phase transitions, and Precipitation

The effects of V on the microstructure and wear resistance of centrifugally cast Ni-hard rolls are investigated under a constant fraction of graphite using electron microscopes and a revolving disk-type high-temperature wear tester. The volume fraction of (V,Nb)C particles was increased at the expense of the volume fraction of cementite with an increase in the V concentration. However, the volume fraction of graphite was held nearly constant by controlling the concentration ratio of Si and Cr. As the V concentration was higher than 3 wt.%, the pro-eutectic phase was changed from austenite to (V,Nb)C carbide. The pro-eutectic vermicular (V,Nb)C particles were segregated to the inner part of the roll during centrifugal casting. The wear resistance was improved with an addition of V due to the high volume fractions of the coarse eutectic and pro-eutectic (V,Nb)C particles and the precipitation hardening of fine (V,Nb)C particles in the martensitic matrix. The worn surface showed that cementite particles acted as the initiation site and propagation route of cracks.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Diagrammes de phases et microstructures développées par solidification et par transformations de phases solide-solide, Phase diagrams and microstructures developed by solidification and solid-solid phase transformations, Solidification, Diffraction RX, XRD, Décomposition spinodale, Spinodal decomposition, Filage état liquide, Melt spinning, Hydrogène, Hydrogen, Loi puissance, Power law, Ley poder, Microstructure, Rayonnement synchrotron, Synchrotron radiation, Réseau cubique centré, BCC lattices, Solidification rapide, Rapid solidification, Sorption, Stockage hydrogène, Hydrogen storage, TDS, Titane alliage, Titanium alloys, Transfert chaleur, Heat transfer, Vanadium alliage, Vanadium alloys, Trempe sur roue, Flow planar casting, BCC alloy, Metal hydrides, Titanium, and Vanadium

The main purpose of the present work was to study the effect of rapid solidification (RS) on the microstructure and hydrogen storage properties of body centred cubic (BCC) Ti rich Ti-V alloys (Ti1-xVx, x = 0.1-0.3). Ribbons were prepared by melt spinning at spinner rotation velocities of 1000-3000 rpm. Ribbon morphology and microstructure were found to depend on the vanadium content and spinner velocity. For Ti0.8V0.2, the relation between the ribbon thickness and velocity can be expressed as a power law function, indicating that, during solidification of the Ti-V ribbons, heat transfer at the interface between spinner and ribbon controls the heat extraction. Temperature desorption spectroscopy (TDS) and in situ synchrotron (SR-XRD) studies of the RS alloys showed that hydrogen desorption from the RS alloy hydrides occurred at lower temperatures than from the as cast alloys. RS caused a microscale chemical element separation in the alloys, which depends on the vanadium content and the spinner velocity. In addition, ribbon recalescence was observed to cause nanoscale chemical redistribution trough spinodal decomposition. These two last features were proposed to be the reasons for the observed thermal destabilisation.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Traitement des matériaux et son effet sur la microstructure et les propriétés, Treatment of materials and its effects on microstructure and properties, Durcissement par soluté, par précipitation et par dispersion; vieillissement, Solid solution, precipitation, and dispersion hardening; aging, Autres traitements thermiques et thermomécaniques, Other heat and thermomechanical treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Elasticité. Plasticité, Elasticity. Plasticity, Alliage base aluminium, Aluminium base alloys, Bande cisaillement, Shear band, Banda cizallamiento, Scherband, Densité dislocation, Dislocation density, Diffraction RX, XRD, Dureté, Hardness, Déformation plastique, Plastic deformation, Extrusion angulaire section constante, ECAP, Limite élasticité, Yield strength, Microstructure, Vieillissement accéléré, Artificial ageing, Envejecimiento acelerado, Kuenstliches Altern, Vieillissement, Aging, 2024 Aluminum alloy, and Mechanical properties

Mechanical properties of the 2024 aluminum alloy, which was plastically deformed by equal channel angular pressing (ECAP) at room temperature and aged naturally and artificially at 70 °C and 100°C for different times, were investigated in this research. Many of the short shear bands were observed on the microstructure after one pass of ECAP and led to fragmentation of grains. Hardness and yield stress of the sample aged naturally after deformation were considerably improved due to increase of dislocation density calculated by XRD data analysis and their interaction with solute atoms during ECAP. The ductility and work hardening exponent of the deformed samples were significantly reduced due to formation of shear bands within the microstructure. However aging the samples immediately after sever plastic deformation at 70 °C and 100 °C caused an additional improvement in hardness and yield stress relative to the samples aged naturally after deformation.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Basse pression, Low pressure, Baja presión, Niederdruck, Carbure fritté, Cemented carbides, Carburo sinterizado, Hartmetall, Dureté, Hardness, Dureza, Haerte, Frittage, Sintering, Sinterización, Sintern, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Propagation fissure, Crack propagation, Propagación fisura, Rissausbreitung, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Rupture transgranulaire, Transgranular fracture, Rotura transcristalina, Transkristalliner Bruch, Ténacité, Fracture toughness, Tenacidad, Bruchzaehigkeit, and Toughness

In this work, the effects of micron grained WC additions on the microstructure and properties of ultrafine WC-(micron WC-Co) cemented carbides produced through low pressure sintering processes were investigated by scanning electron microscope and mechanical properties tests. The results show that the obvious crack deflection and transgranular fracture phenomenon could be observed with the addition of micron WC, which can resist the crack propagation and improve the toughness of cemented carbides. The sintered ultrafine WC-(micron WC-Co) hardmetals demonstrate excellent hardness and fracture toughness values (HV30: 1700 kg/mm2, KIC: 13.82 MPa m1/2). These inhomogeneous ultrafine WC-(micron WC-Co) cemented carbides have considerable potential for use in structural applications.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Traitement des matériaux et son effet sur la microstructure et les propriétés, Treatment of materials and its effects on microstructure and properties, Autres traitements thermiques et thermomécaniques, Other heat and thermomechanical treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Elasticité. Plasticité, Elasticity. Plasticity, Acier austénitique, Austenitic steels, Affinement grain, Grain refinement, Cinétique, Kinetics, Ductilité, Ductility, Laminage à froid, Cold rolling, Limite élasticité, Yield strength, Microstructure, Propriété traction, Tensile properties, Recristallisation, Recrystallization, Recuit, Annealing, Résistance traction, Tensile strength, Structure grain fin, Fine grain structure, Estructura grano fino, Feinkorngefuege, Traitement thermomécanique, Thermomechanical treatments, Bimodal structure, Mechanical properties, and Transformation kinetics

The effects of the multi-cyclic cold rolling and annealing process on the grain refinement and tensile properties of a metastable austenitic steel were investigated. The multi-cyclic thermo-mechanical process yielded the bimodal ultrafine-grained structure through both the reverse transformation and recrystallization during annealing. The kinetics and temperatures of the reverse transformation were related to the average size of coarse grains. Not only yield and tensile strengths but also ductility of the bimodal-grained structure increased with the number of thermo-mechanical cycles.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Transport électronique dans des structures à interface, Electronic transport in interface structures, Argent, Silver, Conductivité électrique, Electrical conductivity, Contact électrique, Electric contacts, Dureté, Hardness, Matériau composite, Composite materials, Microstructure, Oxyde d'argent, Silver oxide, Plata óxido, Oxyde d'étain, Tin oxide, Estaño óxido, Pressage chaud, Hot pressing, Procédé sol gel, Sol-gel process, Synthèse combustion, Combustion synthesis, Ségrégation, Segregation, SnO2, Citric acid, Electrical contact material, and Sol-gel auto-combustion method

A sol-gel auto-combustion method was developed to synthesize the Ag-SnO2 composite powders, which were then used as the starting material to prepare Ag-SnO2 electrical contact materials by hot pressing. It was found that citric acid strongly influences the thermal behaviors, phase evolution, morphology and composition distribution of the Ag-SnO2 composite powders. During the synthesis of Ag-SnO2 composite powders, citric acid can facilitate the formation of sol solution, lower the energy required for the decomposition of dry gel, and reduce the agglomeration of particles. Besides, a comparatively high molar ratio of citric acid to metal ions prevents effectively the occurrence of composition segregation in the Ag-SnO2 electrical contact materials. Therefore, the prepared Ag-SnO2 electrical contact materials have good performances in density, hardness and electric conductivity.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Dynamique réticulaire, Lattice dynamics, Phonons et vibrations dans les réseaux cristallins, Phonons and vibrations in crystal lattices, Bandes et états de phonons, modes normaux, dispersion des phonons, Phonon states and bands, normal modes, and phonon dispersion, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Etats électroniques, Electron states, Densités d'états électroniques et structure de bandes des solides cristallins, Electron density of states and band structure of crystalline solids, Autres métaux et alliages, Other metals and alloys, Actinide alliage, Actinide alloys, Alliage ferromagnétique, Magnetically soft alloy, Aleación ferromagnética, Antimoine alliage, Antimony alloys, Approximation gradient généralisé, Generalized gradient approximation, Calcul APW, APW calculations, Conduction métallique, Metallic conduction, Conducción metálica, Densité état électron, Electronic density of states, Mode vibration, Vibrational modes, Modèle Hubbard, Hubbard model, Moment magnétique localisé, Local magnetic moment, Momento magnético localizado, Structure bande, Band structure, Température Debye, Debye temperature, Uranium alliage, Uranium alloys, Zirconium alliage, Zirconium alloys, Electronic properties, FP-APW + lo, GGA + U, GGA, Magnetic properties, and Thermodynamic properties

Structural, magnetic, electronic and thermodynamic properties of the hexagonal U3ZrSb5 are theoretically investigated by using the full potential linearized augmented plane wave plus local orbital's (FP-LAPW + lo) method. The exchange-correlation potential was treated with the generalized gradient approximation GGA of Wu and Cohen. Moreover, the GGA + U approximation (where U is the Hubbard correlation terms) is employed to treat the f electrons properly. The calculated structural parameters are in good agreement with the experimental data. The magnetic study reveals that U3ZrSb5 is a ferromagnetic material. Furthermore, we present a comparative study between the band structures, electronic structures, total and partial densities of states and local moments calculated within both GGA and GGA + U schemes. Our band structure calculations show the metallic behavior of this ferromagnetic compound. The thermodynamic properties are predicted through the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variation of relative change in volume, heat capacities and the Debye temperature with temperature and pressure are successfully achieved.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Electrodépôt, Electrodeposition, electroplating, Affinement grain, Grain refinement, Alliage base nickel, Nickel base alloys, Concentration impureté, Impurity density, Concentración impureza, Contamination, Dépôt électrolytique, Electrodeposition, Grosseur grain, Grain size, Microstructure, Métal transition alliage, Transition element alloys, Revêtement, Coatings, Spectre SIMS, Secondary ion mass spectra, Tungstène alliage, Tungsten alloys, Chemical synthesis, Nanostructured materials, and Thermal analysis

It is usually difficult to control the incorporation of foreign species in electrodeposited coatings originating from the solvent or the chemical species used for the electrodeposition bath. However, the presence of these impurities can modify their physicochemical properties. In the present study, complementary analytical techniques were used to evaluate the chemical contamination in nickel and nickel-tungsten alloys, electrodeposited from additive free baths. In order to better understand the relationship between impurity content and grain size refinement, the concentration of light elements (H, O and N) was systematically quantified by hot extraction analysis. Also, the distribution of contaminants was evaluated by SIMS analysis. We have shown that in nanocrystalline electrodeposited nickel the grain size refinement and the impurity contents are strongly related. However, in Ni-W alloys the evolution of the contamination is more complex, with a maximum amount for W contents around 10 at.%.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Phénomènes de magnétotransport, matériaux pour le magnétotransport, Magnetotransport phenomena, materials for magnetotransport, Manganites, Addition étain, Tin additions, Concentration impureté, Impurity density, Concentración impureza, Conduction métallique, Metallic conduction, Conducción metálica, Conduction saut, Hopping conduction, Conductivité électrique, Electrical conductivity, Dépendance fréquence, Frequency dependence, Energie activation, Activation energy, Haute fréquence, High frequency, Alta frecuencia, Loi puissance, Power law, Ley poder, Manganite, Manganites, Manganito, Perovskites, Transition métal semiconducteur, Semiconductor metal transition, Transición metal semiconductor, Admittance spectroscopy, Hopping, La0.67Ba0.33Mn1xSnxO3, and Perovskite

Electrical properties of La0.67Ba0.33Mn1-xSnxO3 (0 ≤ x ≤ 0.10) (LBMO-Sn) manganites have been investigated using admittance spectroscopy. The samples exhibit metallic behavior at below metal-semiconductor transition temperature (TMS) and semiconductor-like features above TMS. We find that TMS decreases from 300 K for x = 0 to 240 K for x = 0.10. Due to the substitution of manganese by tin, a decrease of DC conductance was observed throughout the whole explored temperature range. Such behavior is essentially due to the disorder introduced in the charge transfer mechanism when replacing some links of the Mn-O-Mn network by Mn-O-Sn ones. From dc conductance study, electronic conduction is found to be dominated by thermally activated hopping. The tin content affects strongly the activation energy (Ea). Its value increases from 27 meV for x = 0 to 170 meV for x = 0.10. The ac conductance spectrum is found to be sensitive to the tin content. In contrary to free compound, when introducing tin, the material exhibits several features as a function of frequency and temperature. Also, the spectrum is characterized by the appearance of a conductance peaks, which shifts to higher frequencies. Such behavior indicates the presence of relaxation phenomenon in the system. In the high frequency range, ac conductance can be described by the power law G(ω) = Aωs, indicating a hopping conduction process. The variation of the exponent 's' with temperature and tin content, permits us to conclude that hopping model may be the dominating mechanism in the system and confirm that LBMO-Sn system evolves from metallic to semiconductor behavior when increasing tin content.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Propriétés magnétiques des nanostructures, Magnetic properties of nanostructures, Aimantation saturation, Saturation magnetization, Imanación saturación, Coprécipitation, Coprecipitation, Diffraction RX, XRD, Dimension particule, Particle size, Ferrites spinelles, Ferrites spinels, Feritas espinelas, Hystérésis magnétique, Magnetic hysteresis, Microscopie électronique transmission, Transmission electron microscopy, Nanocristal, Nanocrystal, Perméabilité magnétique, Magnetic permeability, Procédé sol gel, Sol-gel process, Spectrométrie FTIR, Fourier-transformed infrared spectrometry, Espectrometría FTIR, Magnetic measurements, Precipitation, and Sol-gel processes

Nanocrystalline Mn-Zn ferrite spinel powders were synthesized by combined coprecipitation and sol-gel autocombustion methods. The effect of the precursors used in the sol-gel autocombustion synthesis on the ferrite's structural and magnetic properties was examined. The ferrite powders were characterized by XRD, FTIR, TEM and SQUID magnetometer measurements. All ferrite powders obtained from different precursors, after gel combustion, were pure spinel phase, without secondary phases. The average crystalline size, estimated from Scherrer equation, was 65.9 and 40.8 nm for ferrite obtained from hydroxide and oxalate precursor, respectively. The saturation magnetization at 2 K (112 and 95.7 emu/g) was smaller than that of bulk material. From the hysteresis loop measurements it can be concluded that the obtained materials show ferrimagnetic behaviour at 2 K. The blocking temperature determined from the ZFC/FC magnetization curve was high (~400 K), which suggested a broad distribution in the particle size. Mn-Zn ferrite prepared from hydroxide precursor showed acceptable magnetic properties with a relatively constant magnetic permeability in the frequency range up to 1000 Hz.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Autres méthodes de préparation et de traitement des matériaux, Materials synthesis; materials processing, Broyeur boulet, Ball mill, Molino bolas, Compactage poudre, Powder compaction, Compactación polvo, Diffraction RX, XRD, Durée maintien, Holding time, Tiempo funcionamiento, Effet température, Temperature effects, Frittage par décharge plasma, Spark plasma sintering, Propriété mécanique, Mechanical properties, Siliciure de molybdène, Molybdenum silicide, Molibdeno siliciuro, Stoechiométrie, Stoichiometry, MoSi2, and Spark Plasma Sintering (SPS)

In this research, dense MoSi2 was fabricated using of spark plasma sintering. Mo and Si powders according to MoSi2 stoichiometry ratio was mixed by a high energy ball mill for 1 h. The milled powders were compacted into green body by using 200 MPa uniaxial pressure. Then the samples were synthesized and sintered in one step by using spark plasma sintering apparatus at temperature from 1273 to 1573 K. X-ray diffraction results showed that at 1273 K there is no reaction between Mo and Si. By increasing temperature to 1373 K the reaction between Mo and Si was took place. Also, the effect of temperature and holding time on the in situ synthesis-sintering, density and mechanical properties was also investigated.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Electrodes: préparations et propriétés, Electrodes: preparations and properties, Batterie lithium, Lithium battery, Cathode, Cátodo, Couche superficielle, Surface layer, Capa superficial, Diffraction RX, X ray diffraction, Difracción RX, Oxyde, Oxides, Óxido, Spectre photoélectron RX, X-ray photoelectron spectra, Spinelles, Spinels, Espinelas, Traitement surface, Surface treatment, Tratamiento superficie, Transfert charge, Charge transfer, Transferencia carga, Cathode materials, Lithium-ion battery, Spinel-like structure, and Surface modification

Li1.375Ni0.25Mn0.75O2+γ exhibits an obviously enhanced electrochemical performance after AlF3 surface modification, including the high initial discharge capacities of 276.8 mA h g―1 and high coulombic efficiency of 93.6%. The results from powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP) and galvanostatical test confirm that its electrochemical improvement can be mainly attributed to the appearance of spinel-like structure on the surface of the layered material induced by AlF3-modified. Moreover, the reduced charge transfer resistance (Rct) during cycling contributes to a better cycle stability of AIF3-modified Li1.375Ni0.25Mn0.75O2+γ.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Allongement mécanique, Elongation (mechanics), Alargamiento (mecánico), Chargement hydrogène, Hydrogen charging, Cargamento hidrógeno, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Fragilisation hydrogène, Hydrogen embrittlement, Fragilización hidrógeno, Wasserstoffversproedung, Maclage, Twinning, Chocleo, Zwillingsbildung, Recuit, Annealing, Recocido, Gluehen, Rupture, Ruptura, Bruch, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, Transition ductile fragile, Ductile brittle transition, Transición ductil frágil, Uebergang duktil sproed, Mechanical twin, and Pre-strain

The effect of pre-strain on hydrogen embrittlement (HE) was investigated using STS 310S, considering its application to a ferrous cylinder liner for hydrogen storage. Whereas tensile strength was insignificantly influenced by hydrogen charging, elongation was decreased due to a ductile to brittle fracture transition. However, the degree of the reduction in elongation by hydrogen charging was decreased with increasing pre-strain, indicating that pre-straining improved the resistance to HE by suppressing the fracture transition. The cause for suppression of the fracture transition by pre-strain was investigated through the analyses of strain hardening behavior and thermal desorption of hydrogen. The strain hardening rate curves of annealed and pre-strained specimens was divided into several stages, which were greatly affected by primary and secondary twinning, regardless of hydrogen charging. This strain hardening analysis showed that pre-straining suppressed mechanical twinning during tensile deformation. The thermal desorption analysis revealed that the migration of diffusible hydrogen atoms to twin boundaries was hindered by pre-strain. Therefore, the reason why pre-strain suppressed the fracture transition to improve the resistance to HE was because pre-strain hindered both mechanical twinning during tensile deformation and hydrogen delivery to twin boundaries not to form highly hydrogen-concentrated twin boundaries.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Assemblage et découpage thermique: aspects métallurgiques, Joining, thermal cutting: metallurgical aspects, Soudage, Welding, Cinétique, Kinetics, Cinética, Kinetik, Croissance grain, Grain growth, Crecimiento grano, Kornwachstum, Dendrite, Dendrita, Dendrit, Elément alliage, Alloying element, Elemento aleación, Legierungselement, Grosseur grain, Grain size, Grosor grano, Korngroesse, Inconel 625, Microstructure, Microestructura, Mikrogefuege, Phase Laves, Laves phase, Fase Laves, Laves Phase, Précipité, Precipitate, Precipitado, Ausscheidungsprodukt, Soudage TIG, GTA welding, Soldeo TIG, WIG Schweissen, Structure basaltique, Columnar structure, Estructura columnar, Stengelkristallgefuege, Ségrégation, Segregation, Segregación, Seigerung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, Coarsening, Inconel 625 deposited metal, Phase transformation, and Post-weld heat treatment

The effect of post-weld heat treatment (PWHT) temperatures on the microstructure of Inconel 625 deposited metal (DM) was examined using an optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The transformation mechanism of the yʺ → δ phase and the grain growth kinetics of the y' phase during PWHT were revealed. The results indicate that the microstructure of as-welded DM is composed of columnar grains of different sizes, of which the average grain size is approximately 160 μm. Certain precipitates, such as the dispersed γʹ phase, blocky MC-type carbide and irregular shape Laves phase, precipitate in the microstructure of the as-welded DM. Compared with as-welded DM, the microstructure of DM after PWHT at 650 °C for 4 h shows minimal variation. With an increase in PWHT temperature, a large number of body-centered tetragonal y phases precipitate at interdendrite regions in the microstructure of DM after PWHT at 750 °C for 4 h. When the PWHT temperature increases to 850 °C, the metastable γʺ phase directly transforms into a stable δ phase in shear mode, which exhibits a similar chemical composition but a different crystal structure than the y phase. At 950 °C, the γʺ phase and the δ phase disappear, whereas certain M6C-type carbides precipitate at the grain boundaries. Alloying elements such as Nb, Mo, Si, Al and Fe in the microstructure of as-welded DM exhibit segregation behavior. Due to an increasing PWHT temperature, the segregation behavior constantly weakens with minimal evolution to the temperature of 750 °C. Above this temperature, partition coefficients tend toward 1, and composition heterogeneity disappears at 950 °C. During PWHT, the y' phase continuously coarsens with an increase in PWHT temperature. The dynamic analysis shows that the coarsening behavior of the y' phase corresponds with the formula: d3 ― d30 = A · e―Q/RT /T · t with an activation energy of 253 kJ/mol.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Propriétés magnétiques des nanostructures, Magnetic properties of nanostructures, Aimantation saturation, Saturation magnetization, Imanación saturación, Aimantation, Magnetization, Cobalt alliage, Cobalt alloys, Composition chimique, Chemical composition, Dépôt électrolytique, Electrodeposition, Etain alliage, Tin alloys, Force coercitive, Coercive force, Microstructure, Métal transition alliage, Transition element alloys, Nanofil, Nanowires, Recuit, Annealing, Ségrégation, Segregation, and Magnetic behavior

CoxSn1-x alloy nanowires were ac-pulse electrodeposited into the highly ordered alumina template in the same electrolyte concentration. The effect of off-time between pulses (0, 20, 50, 100 and 200 ms) on the magnetic properties and microstructure of the CoxSn1-x nanowires was investigated. Using a single electrodeposition bath, Sn content increased in the range of 3-55 at.% with increasing the off-time. Improving hcp-Co (002) crystalline orientation with increasing the off-time was the main source to increase the coercivity of as-deposited alloy nanowires. Segregation of magnetic grains by Sn element led to improve the coercivity of the annealed samples. Existence of non-magnetic Sn prevented the oxidation of magnetic grains thereby saturation magnetization of the annealed samples was unchanged.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Autres méthodes de préparation et de traitement des matériaux, Materials synthesis; materials processing, Alliage mécanique, Mechanical alloying, Densité, Density, Diffraction RX, XRD, Dureté Vickers, Vickers hardness, Frittage par décharge plasma, Spark plasma sintering, Microstructure, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Siliciure de molybdène, Molybdenum silicide, Molibdeno siliciuro, Stoechiométrie, Stoichiometry, and MoSi2

In this research the effect of mechanical alloying on the in situ synthesis―sintering behavior and mechanical properties of MoSi2 has been investigated. The Mo and Si powders according to MoSiz stoichiometric composition were mechanically alloyed at different times. Then, the powders were subjected to spark plasma sintering process for preparing monolithic MoSi2. X-ray diffraction pattern of the sintered samples showed that by increasing the mechanical alloying time, Mo5Si3 has been formed. It seems that the formation of Mo5Si3 is due to the effect of mechanical alloying on microstructure and thermodynamic condition of the reaction.