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Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Défauts et impuretés dans les cristaux; microstructure, Defects and impurities in crystals; microstructure, Joints de grains et joints de macle, Grain and twin boundaries, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Recuit, Annealing, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Elasticité. Plasticité, Elasticity. Plasticity, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Défaut cristallin, Crystal defect, Defecto cristalino, Dépôt laser, Laser deposition, Depósito laser, Fracture, Fractura, Fusion laser, Laser fusion, Fusión láser, Joint grain, Grain boundary, Limite grano, Korngrenze, Microstructure, Microestructura, Mikrogefuege, Phase alpha, Alpha phase, Fase alfa, Alpha Phase, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Précipité, Precipitate, Precipitado, Ausscheidungsprodukt, Recuit, Annealing, Recocido, Gluehen, Rupture intergranulaire, Intergranular fracture, Rotura intergranular, Korngrenzenbruch, Titane alliage, Titanium alloy, Titanio aleación, Titanlegierung, Traitement par laser, Laser assisted processing, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, 6172M, 8140J, Grain boundaries, Heat treatments, and Laser melting deposition

Laser melting deposition (LMD), which fabricates near-net-shape components directly by melting powder layer by layer, is used to manufacture Ti-5Al-5Mo-5V-1Cr-1Fe near β titanium alloy samples. In as-deposited alloy, ultrafine basket-weave microstructure and continuous grain boundary α (αGB) are observed. And the as-deposited alloy exhibits high strength but low ductility. Then the annealing treatment is applied to improve the ductility, but the strength of the annealed alloy is too low. To obtain good comprehensive tensile properties, the traditional standard triplex heat treatment usually applied for wrought Ti-5Al-5Mo-5V-1Cr-1Fe alloy is employed. The results show that the alloy has high strength. The ductility is also improved, but still not satisfactory, because the continuous αGB remains and is accompanied with soft α phase precipitate-free zones (PFZ) which results in the intergranular fracture. Accordingly, a subtransus triplex heat treatment is designed, which can significantly reduce the continuous αGB. And as expected, the ductility is significantly improved, and the predominant fracture model changes to be transgranular.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Elasticité, constantes d'élasticité, Elasticity, elastic constants, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Trempe et revenu, Hardening. Tempering, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Acier outil, Tool steel, Acero herramienta, Werkzeugstahl, Allongement mécanique, Elongation (mechanics), Alargamiento (mecánico), Austénite résiduelle, Retained austenite, Austenita residual, Restaustenit, Carbone, Carbon, Carbono, Kohlenstoff, Densité énergie, Energy density, Densidad energía, Dispersion, Dispersión, Distribution non uniforme, Non uniform distribution, Distribución no uniforme, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Durcissement laser, Laser hardening, Durcissement superficiel, Surface hardening, Endurecimiento superficial, Etat fondu, Molten state, Estado fundido, Fraction volumique, Volume fraction, Fracción volumétrica, Fusion laser, Laser fusion, Fusión láser, Fusion surface, Surface melting, Fusión superficie, Oberflaechenschmelzen, Laser injection, Injection laser, Laser inyección, Laser semiconducteur, Semiconductor laser, Laser semiconductor, Limite élasticité, Yield strength, Límite elasticidad, Streckgrenze, Martensite, Martensita, Martensit, Microdureté, Microhardness, Microdureza, Mikrohaerte, Microstructure, Microestructura, Mikrogefuege, Onde entretenue, Continuous wave, Onda continua, Propriété mécanique, Mechanical properties, Propiedad mecánica, Précipité, Precipitate, Precipitado, Ausscheidungsprodukt, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Revenu, Tempering, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, Traitement par laser, Laser assisted processing, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 6220D, 8140J, AISI H13 tool steel, Laser surface hardening, and Laser surface melting

The present study concerns laser surface hardening (LSH) and melting (LSM) of AISI H13 tool steel using a high power continuous wave diode laser. Depth of surface hardened or melted layer increases with increase in incident laser energy density. Surface melting occurs at a higher laser energy density ( > 75 J/ mm2) and leads to the formation of inhomogeneous microstructure comprising non-uniform distribution of retained austenite, carbides (along inter-dendritic boundary) and martensite with their respective volume fractions varying with depth. Application of intermediate laser energy density (50―75 J/mm2) yields a hardened layer with dispersion of ultrafine mixed carbides (M23C6, M7C3, MC or M2C). Laser treatment with a very low laser energy density ( < 50 J/mm2) leads to formation of an over-tempered microstructure consisting of low carbon martensite and coarse carbide precipitates. Micro-tensile studies with specially machined samples from the surface melted zone following LSM with a laser energy density of 100 J/mm2 records a high yield strength of 1310 MPa along with poor ductility, marked by brittle failure. On the other hand, a similar sample from laser surface hardened zone treated with a laser energy density of 62.5 J/mm2 yielded even higher yield strength of 1460 MPa with a maximum elongation of 3.6%. Though both LSH and LSM produced higher yield strength compared to hardened and tempered AISI H13 tool steel, LSH yielded a combination of higher elongation (3.6%), than that after LSM (0.97%), with high yield strength and hence was considered a better option.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Dispositifs optoélectroniques, Optoelectronic devices, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Couche mince métallique, Metallic thin films, Coulée en moule, Casting, Colada molde, Giessen, Diode électroluminescente, Light emitting diode, Diodo electroluminescente, Etat fondu, Molten state, Estado fundido, Interface, Interfase, Grenzflaeche, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Mouillabilité, Wettability, Remojabilidad, Benetzbarkeit, Mouillage, Wetting, Remojo, Phénomène interface, Interface phenomena, Revêtement, Coatings, Revestimiento, Ueberzug, Réaction interface, Interface reaction, Reacción interfase, Résistance cisaillement, Shear strength, Resistencia cizallamiento, Scherfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vide poussé, High vacuum, Zinc, Zink, 8560J, Substrat Al2O3, Aluminum alloys, Bi-metallic casting, Interfacial phenomena, and Magnesium alloys

This paper summarizes the bi-metallic experiments using a high-vacuum test apparatus to understand the interfacial phenomena between Mg (AM60) and Al (A390) samples. The test results show significantly improved wetting and metallurgical bonding between the molten magnesium and aluminum substrate when a zincate+galvanizing surface treatment was applied. This surface treatment removes the intrinsic Al2O3 layer on the aluminum substrate and, in tum, forms a very thin metallic zinc film on the substrate. Interfacial reactions between the aluminum substrate and the molten magnesium led to the improved metallurgical bonding and significantly improved shear strength in the bi-metallic samples with zincate+galvanizing surface treatment. However, long reaction times led to the formation of excessive intermetallic compounds at the interface, which reduced bond strength.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Transformations martensitiques, Martensitic transformations, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Fatigue, Acier inoxydable 304, Stainless steel-304, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Contrainte compression, Compressive stress, Tensión compresión, Druckspannung, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Contrainte superficielle, Surface stresses, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Cristal lamellaire, Layered crystals, Cristallisation, Crystallization, Cristalización, Kristallisation, Diffraction électron, Electron diffraction, Difracción electrónica, Elektronenbeugung, Dislocation, Dislocación, Versetzung, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Durcissement, Hardening, Endurecimiento, Haerten, Dureté, Hardness, Dureza, Haerte, Echelle nanométrique, Nanometer scale, Ecrouissage, Work hardening, Endurecimiento en frío, Face cristalline, Crystal face, Cara cristal, Kristallebene, Fatigue, Fatiga, Ermuedung, Fraction volumique, Volume fraction, Fracción volumétrica, Germination dislocation, Dislocation nucleation, Germinación dílocación, Versetzungskeimbildung, Limite fatigue, Fatigue limit, Límite fatiga, Ermuedungsgrenze, Macle mécanique, Mechanical twin, Macla mecánica, Verformungszwilling, Martensite, Martensita, Martensit, Microstructure, Microestructura, Mikrogefuege, Nanocristal, Nanocrystal, Nanostructure, Nanoestructura, Propriété mécanique, Mechanical properties, Propiedad mecánica, Source dislocation, Dislocation source, Fuente dislocación, Versetzungsquelle, Striction (mécanique), Necking, Estricción (mecánica), Subsurface, Subsuelo, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Transformation martensitique, Martensitic transformation, Transformación martensítica, Martensitische Umwandlung, Ultrason, Ultrasound, Ultrasonido, Ultraschall, 6114L, 6172L, 6470K, 8130K, Deformation twins, Fatigue performance, Gradient microstructure, Modification (UNSM), Precession electron diffraction (PED), Residual stresses, and Ultrasonic Nano-crystal Surface

In this study, the effects of Ultrasonic Nano-crystal Surface Modification (UNSM) on residual stresses, microstructure changes and mechanical properties of austenitic stainless steel 304 were investigated. The dynamic impacts induced by UNSM leads to surface nanocrystallization, martensite formation, and the generation of high magnitude of surface compressive residual stresses (-1400 MPa) and hardening. Highly dense deformation twins were generated in material subsurface to a depth of 100 μm. These deformation twins significantly improve material work-hardening capacity by acting both as dislocation blockers and dislocation emission sources. Furthermore, the gradually changing martensite volume fraction ensures strong interfacial strength between the ductile interior and the two nanocrystalline surface layers and thus prevents early necking. The microstructure with two strong surface layers and a compliant interior embedded with dense nanoscale deformation twins and dislocations leads to both high strength and high ductility. The work-hardened surface layers (3.5 times the original hardness) and high magnitude of compressive residual stresses lead to significant improvement in fatigue performance; the fatigue endurance limit was increased by 100 MPa. The results have demonstrated that UNSM is a powerful surface engineering technique that can improve component mechanical properties and performance.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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 de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Anisotropie, Anisotropy, Anisotropía, Carbone, Carbon, Carbono, Kohlenstoff, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Durée vie fatigue, Fatigue life, Longevidad fatiga, Ermuedungslebensdauer, Evaluation performance, Performance evaluation, Evaluación prestación, Fatigue, Fatiga, Ermuedung, Fusion laser, Laser fusion, Fusión láser, Microstructure, Microestructura, Mikrogefuege, Porosité, Porosity, Porosidad, Porositaet, Procédé fabrication, Manufacturing process, Procedimiento fabricación, Fertigungsverfahren, Titane, Titanium, Titanio, Titan, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Fusion sélective par laser, Selective laser melting, Ti90Al6V4, Additive Manufacturing, and Laser

Additive Manufacturing of titanium components holds promise to deliver benefits such as reduced cost, weight and carbon emissions during both manufacture and use. To capitalize on these benefits, it must be shown that the mechanical performance of parts produced by Additive Manufacturing can meet design requirements that are typically based on wrought material performance properties. Of particular concern for safety critical structures are the fatigue properties of parts produced by Additive Manufacturing. This research evaluates the fatigue properties of Ti-6Al-4V specimens produced by the Selective Laser Melting additive manufacturing process. It was found that the fatigue life is significantly lower compared to wrought material. This reduction in fatigue performance was attributed to a variety of issues, such as microstructure, porosity, surface finish and residual stress. There was also found to be a high degree of anisotropy in the fatigue performance associated with the specimen build orientation.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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 de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Fatigue, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Durcissement, Hardening, Endurecimiento, Haerten, Fatigue polycyclique, High cycle fatigue, Fatiga polyciclica, Limite fatigue, Fatigue limit, Límite fatiga, Ermuedungsgrenze, Microdureté, Microhardness, Microdureza, Mikrohaerte, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Multicouche, Multiple layer, Capa múltiple, Mehrfachschicht, Nanostructure, Nanoestructura, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Renforcement mécanique, Strengthening, Refuerzo mecánico, Résistance fatigue, Fatigue strength, Resistencia fatiga, Dauerfestigkeit, Titane alliage, Titanium alloy, Titanio aleación, Titanlegierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vibration, Vibración, Schwingung, Grenaillage choc laser, Laser shock peening, Substrat alliage titane, and TC6 titanium alloy

Laser shock peening (LSP) is an innovative surface treatment technique, and can significantly improve the fatigue performance of metallic components. In this paper, the objective of this work was to improve the fatigue resistance of TC6 titanium alloy by laser shock peening. Firstly, the effects on the microstructure and mechanical properties with different LSP impacts were investigated, which were observed and measured by X-ray diffraction (XRD), transmission electron microscope (TEM), residual stress tester and microhardness tester. Specially, nanostructure was detected in the laser-peened surface layer with multiple LSP impacts. Whereafter, a better parameter was chosen to be applied on the standard vibration fatigue specimens. Via the high-cycle vibration fatigue tests, the high cycle fatigue limits of the specimens without and with LSP were obtained and compared. The fatigue results demonstrate that LSP can effectively improve the fatigue limit of TC6 titanium alloy. The strengthening mechanism was indicated by analyzing the effects on the microstructure and mechanical properties comprehensively.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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 croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Alliage base nickel, Nickel base alloys, Concentration contrainte, Stress concentration, Concentración restringida, Spannungskonzentration, Condition initiale, Initial condition, Condición inicial, Contrainte compression, Compressive stress, Tensión compresión, Druckspannung, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Contrainte traction, Tensile stress, Tensión traccíon, Zugspannung, Coupe transversale, Cross section, Corte transverso, Déformation plastique, Plastic deformation, Deformación plástica, Plastische Verformung, Effet contrainte, Stress effects, Eprouvette entaillée, Notched test piece, Probeta entallada, Kerbpruefkoerper, Fatigue, Fatiga, Ermuedung, Fissure fatigue, Fatigue crack, Fisura fatiga, Ermuedungsriss, Grenaillage, Shot peening, Granalla, Kugelstrahlen, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Wachstumsmechanismus, Profil profondeur, Depth profile, Perfil profundidad, Tiefenprofil, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résultat expérimental, Experimental result, Resultado experimental, Section efficace, Cross section (collision), Sección eficaz, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 8110A, Déformation localisée, Localized deformation, Deformación localizada, Mechanical behavior, Nickel-base superalloy, and Shot peen

Shot peening is a well-established surface treatment process that imparts large compressive residual stresses onto the surface and at shallow depths to retard initiation and growth of fatigue cracks. The plastic deformation developed during the surface treatment sets up a constraint that retains compressive stresses on the surface balanced by tensile residual stresses in the interior. However, component service histories that produce subsequent plastic deformation may redistribute these residual stresses. In most engineering components, this additional plastic deformation is localized to stress concentration sites such as holes, notches, and fillets. In the case of gross plastic deformation where the entire cross section experiences material yielding the residual stress profile may redistribute, resulting in tensile stresses on the outside surface balanced by compression in the interior. This paper describes a series of experiments combined with models to explain the redistribution in residual stress depth profiles subject to applied stresses producing gross plastic strains in shot peened laboratory specimens. The initial room temperature residual stress and plastic strain profiles provide initial conditions for predictions. Model predictions correlate well with experimental results on shot peened dogbone specimens subject to single cycle and fatigue loading conditions at elevated temperature. Experiments on shot peened notched specimens do not exhibit the same stress redistribution even for larger applied stresses.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Traitements thermochimiques et traitements par diffusion, Thermochemical treatment and diffusion treatment, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Frottement. Usure, Contact of materials. Friction. Wear, Amorçage fissure, Crack initiation, Iniciación grieta, Risseinleitung, Contrainte compression, Compressive stress, Tensión compresión, Druckspannung, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Durcissement, Hardening, Endurecimiento, Haerten, Fissure fatigue, Fatigue crack, Fisura fatiga, Ermuedungsriss, Nitruration, Nitriding, Nitruración, Nitrieren, Particule fine, Fine particle, Partícula fina, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résistance fatigue, Fatigue strength, Resistencia fatiga, Dauerfestigkeit, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Subsurface, Subsuelo, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, Traitement thermochimique, Thermochemical treatment, Tratamiento termoquímico, Thermochemische Behandlung, 8140J, 8165L, Ti90Al6V4, Combination treatment, Hybrid surface treatment, and Ti-6Al-4V

This study was conducted to comprehensively investigate the effect of combination treatment on the wear resistance, mechanical properties, and fatigue strength of Ti―6Al―4V alloy. The combination treatment was composed of plasma nitriding, short-time duplex heat treatment (hereafter, duplex heat treatment), and fine-particle bombarding (FPB). A hardened layer was formed by plasma nitriding. The substrate was strengthened by duplex heat treatment. The brittle compound layer, formed by plasma nitriding, was eliminated by FPB, and also high compressive residual stress was introduced. Wear resistance was improved by combination treatment; however, hybrid surface treatment, composed of plasma nitriding and FPB, was more effective to improve wear resistance than combination treatment. The tensile strength was improved 30% by combination treatment. Fatigue crack initiation from the surface was strongly suppressed by the formed layer and introduced high compressive residual stress. Moreover, subsurface crack initiation was suppressed by the strengthened substrate. As a result, fatigue strength was greatly improved, by 59%, by the combination treatment.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, 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, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Recuit, Annealing, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Affinement grain, Grain refinement, Afino grano, Kornfeinen, Broyeur attrition, Attrition mill, Molino atrición, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Diffraction électron rétrodiffusé, EBSD, Diffractión electrón retrodifusa, Diffractomètre RX, X ray diffractometer, Difractómetro rayos X, Roentgenstrahlendiffraktometer, Dislocation, Dislocación, Versetzung, Dureté, Hardness, Dureza, Haerte, Défaut cristallin, Crystal defect, Defecto cristalino, Déformation plastique, Plastic deformation, Deformación plástica, Plastische Verformung, Emission champ, Field emission, Emisión campo, Feldemission, Emission électronique champ, Electron field emission, Emisión electrónica campo, Grande déformation, High strain, Gran deformación, Joint grain, Grain boundary, Limite grano, Korngrenze, Macle mécanique, Mechanical twin, Macla mecánica, Verformungszwilling, Microscope balayage, Scanning microscope, Microscopio barrido, Rastermikroskop, Microscope laser, Laser microscope, Microscopio láser, Microscopie confocale, Confocal microscopy, Microscopía confocal, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Microscopie électronique, Electron microscopy, Microscopía electrónica, Elektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Propriété mécanique, Mechanical properties, Propiedad mecánica, Recuit, Annealing, Recocido, Gluehen, Traitement mécanique, Mechanical treatment, Tratamiento mecánico, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 6172L, 6172M, Substrat acier inoxydable, Austenite, Grain boundaries, and X-ray diffraction

Severe plastic deformation (SPD) was performed on AISI304 stainless steel by surface mechanical attrition treatment (SMAT). The microstructure evolution of the specimens along the depth direction were examined by transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) associated with field emission scanning electron microscope (FESEM). The results show that the specimens by SMAT can be divided into three regions. Region I is the untreated one, where a large number of annealing twins exist. Region II is the small plastic-deformed one, where the grains are deformed by dislocation slipping. Region III is the severe plastic-deformed one, where the grains are deformed by mechanical twinning. The hardness of the untreated and the treated specimens were determined, which shows that the hardness of the untreated specimen (including region I) is about 250HV, while the hardness is uniformly increased from region II to region III, and the largest value appears on the surface. The untreated and the 600 N-treated specimens were determined and observed by X-ray diffractometer (XRD) and confocal laser scanning microscope (CLSM), which shows that the SMAT treated specimen exhibits a layer of ultra-fined γ-Fe grains on the treated surface.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Corrosion, Mécanismes fondamentaux et formes de la corrosion, Corrosion mechanisms, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Bore, Boron, Boro, Bor, Carbone, Carbon, Carbono, Kohlenstoff, Corrosion, Corrosión, Korrosion, Couche interfaciale, Interfacial layer, Capa interfacial, Couche mince, Thin film, Capa fina, Duennschicht, Couche transition, Transition layer, Capa transición, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Dépôt chimique phase vapeur, Chemical vapor deposition, Depósito químico fase vapor, Chemisches Aufdampfen, Fibre, Fiber, Fibra, Faser, Flexion, Bending, Flexión, Biegung, Interface, Interfase, Grenzflaeche, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résistance compression, Compressive strength, Resistencia compresión, Druckfestigkeit, Résistance flexion, Bending strength, Resistencia flexión, Biegefestigkeit, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Texture, Textura, Textur, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 8115G, 8140G, 8245B, Banding, Composites, Interfaces, and Mechanical characterization

Before being densified by chemical vapor deposition, carbon preform was modified by boron. The mechanical property and resistance to atomic oxygen corrosion of carbon/carbon composites were investigated. The results show that fiber surface modification induces the deposition of high texture pyrocarbon and a moderate interfacial transition layer between carbon fibers and matrix carbon. After being modified by boron, the flexural and compressive strength of carbon/carbon composite is significantly increased. The bending curve has been adjusted with obvious pseudo-ductility phenomenon. The resistance ability to atomic oxygen corrosion is improved significantly. The mass loss and corrosion degree of the modified composite are lower than that of pure carbon/carbon composite.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Transformations martensitiques, Martensitic transformations, Traitement des matériaux et son effet sur la microstructure et les propriétés, Treatment of materials and its effects on microstructure and properties, Ecrouissage, durcissement par déformation; recuit, trempe, revenu, restauration et recristallisation; textures, Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Elasticité. Plasticité, Elasticity. Plasticity, Acier inoxydable 304, Stainless steel-304, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Affinement grain, Grain refinement, Afino grano, Kornfeinen, Broyeur attrition, Attrition mill, Molino atrición, Cristal lamellaire, Layered crystals, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Dislocation, Dislocación, Versetzung, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Durcissement, Hardening, Endurecimiento, Haerten, Déformation à chaud, Hot deformation, Deformación en caliente, Warmverformung, Ecrouissage, Work hardening, Endurecimiento en frío, Effet température, Temperature effect, Efecto temperatura, Temperatureinfluss, Grosseur grain, Grain size, Grosor grano, Korngroesse, Laminage à chaud, Hot rolling, Laminado en caliente, Warmwalzen, Maclage, Twinning, Chocleo, Zwillingsbildung, Martensite secondaire, Secondary martensite, Martensita secundaria, Sekundaerer Martensit, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Nanomatériau, Nanostructured materials, Nanostructure, Nanoestructura, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Recristallisation dynamique, Dynamical recrystallization, Recristalización dinamica, Dynamische Rekristallisation, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Renforcement mécanique, Strengthening, Refuerzo mecánico, Résultat expérimental, Experimental result, Resultado experimental, Structure grain fin, Fine grain structure, Estructura grano fino, Feinkorngefuege, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, Traitement mécanique, Mechanical treatment, Tratamiento mecánico, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Transformation martensitique, Martensitic transformation, Transformación martensítica, Martensitische Umwandlung, 6172L, 8140J, Nanostructured material, SMAT, and Warm deformation

A layered and nanostructured (LN) stainless steel was fabricated by surface mechanical attrition treatment (SMAT) combined with warm co-rolling (WCR) in order to improve the low ductility of nanostructured metallic materials. The influences of rolling temperature and strain on the microstructure are investigated. The microstructure of LN steel is characterized by methods of transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results reveal that the microstructure of LN steels presents a periodic distribution of nanocrystalline layer, ultra-fine grained layer and coarse grained layer with graded transition of grain size. The integrated effects of SMAT and WCR on the refinement of grain size, involving in dislocation subdivision, twinning and dynamic recrystallization, are discussed. The tensile properties of LN steels exhibit both high strength and good ductility resulting from good work hardening behavior. The strengthening mechanisms by grain size refinement, α'-martensite transformation and twinning are explored.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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 croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Théorie et modèles de la croissance cristalline; physique de la croissance cristalline, morphologie cristalline et orientation cristalline, Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Fatigue, Contrainte compression, Compressive stress, Tensión compresión, Druckspannung, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Distribution contrainte, Stress distribution, Campo restricción, Mechanisches Spannungsfeld, Durcissement, Hardening, Endurecimiento, Haerten, Effet surface, Surface effect, Efecto superficie, Oberflaecheneinfluss, Essai Vickers, Vickers test, Ensayo Vickers, Vickers Versuch, Fatigue polycyclique, High cycle fatigue, Fatiga polyciclica, Fissure fatigue, Fatigue crack, Fisura fatiga, Ermuedungsriss, Fonction répartition, Distribution function, Función distribución, Indentation, Indentación, Microdureté, Microhardness, Microdureza, Mikrohaerte, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Wachstumsmechanismus, Polissage, Polishing, Pulimiento, Polieren, Profil profondeur, Depth profile, Perfil profundidad, Tiefenprofil, Propriété mécanique, Mechanical properties, Propiedad mecánica, Renforcement mécanique, Strengthening, Refuerzo mecánico, Subsurface, Subsuelo, Titane alliage, Titanium alloy, Titanio aleación, Titanlegierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 8110A, Grenaillage choc laser, Laser shock peening, Fatigue performance, and Near-α titanium alloy

Laser shock peening (LSP) or Laser shock processing is a novel surface treatment technique for strengthening metal materials. In this work, several investigations were performed to evaluate the effect of LSP on some mechanical properties of a near-a titanium alloy Ti834. Micro-hardness measurements of the untreated and LSP treated specimens were carried out by using a Vickers indenter. The depth profiles of subsurface micro-hardness of the shocked region were determined through the electro-polishing material removal in steps of 0.1 mm. It is observed that the micro-hardness of Ti834 alloy can be improved by LSP, and repeated shocks have a very beneficial effect on surface hardening. Residual stress distribution as a function of depth was determined by X-ray diffraction (XRD) with the sin2 ψ method. The high-cycle fatigue performance of the alloy was investigated and the fractographs of fatigue specimens were observed by SEM. Results reveal that the high-cycle fatigue life of Ti834 alloy increases after laser shock peening due to the introduction of compressive stress which can delay the initiation and growth of the fatigue crack.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Elasticité et anélasticité, Elasticity and anelasticity, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Elasticité. Plasticité, Elasticity. Plasticity, Rupture, Fractures, Acier martensitique, Martensitic steel, Acero martensítico, Martensitischer Stahl, Clivage, Cleavage, Clivaje, Critère rupture, Fracture criterion, Criterio ruptura, Diffusion(transport), Diffusion, Dislocation, Dislocación, Versetzung, Défaut, Defect, Defecto, Fehler, Dépendance du temps, Time dependence, Dependencia del tiempo, Dépendance température, Temperature dependence, Désorption, Desorption, Desorción, Effet contrainte, Stress effects, Endommagement, Damaging, Deterioración, Energie cohésion, Cohesive energy, Energía cohesión, Essai traction, Tension test, Ensayo tracción, Zugversuch, Fracture, Fractura, Fragilisation hydrogène, Hydrogen embrittlement, Fragilización hidrógeno, Wasserstoffversproedung, Inclusion, Inclusión, Einschluss, Interface, Interfase, Grenzflaeche, Lacune, Vacancy, Cavidad, Leerstelle, Piégeage, Trapping, Captura, Einfang, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Précipité, Precipitate, Precipitado, Ausscheidungsprodukt, Rupture clivage, Cleavage fracture, Fractura transcristalina, Spaltbruch, Rupture ductile, Ductile fracture, Ruptura dúctil, Verformungsbruch, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Trempe et revenu, Quenching and tempering, Temple y revenido, Vergueten, 6172L, 8140J, Backing time, and Damage

The hydrogen embrittlement (HE) may sometimes affect the Martensitic Steels following surface treatments. This damage appears to be dependent on baking time during which hydrogen can be desorbed from the sample and/or be redistributed within the material. The present study aims to identify the evolution of different hydrogen states in a quenched and tempered martensitic steel during the desorption phase and to evaluate their effects on the mechanical behavior in a simple tensile test on smooth specimens. The present work shows that during baking phase at specific temperatures, a real competition exists between desorption and deep trapping on specific defects (vacancies and/or dislocations) of diffusible hydrogen. The transition between both the regimes implies a times range for which the initially ductile rupture becomes a quasi-cleavage process. This transition of the fracture mechanisms is directly correlated to a time at which the flux of hydrogen is maximized. The critical stress for quasi-cleavage fracture was assessed at 435 MPa and ductile fracture criterion follows a Beremin form, which suggests a predominance of decohesion at inclusion and/or precipitate interfaces less affected by hydrogen (critical stress around 600 MPa). .

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Effets physiques d'irradiation, défauts d'irradiation, Physical radiation effects, radiation damage, Electrons et positons, Electrons and positron radiation effects, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de nanofabrication, Methods of nanofabrication, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Couche mince, Thin film, Capa fina, Duennschicht, Couche mélangée, Mixed layer, Capa mezclada, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Effet rayonnement, Radiation effect, Efecto radiación, Strahleneffekt, Faisceau électronique, Electron beam, Haz electrónico, Elektronenstrahl, Fissure, Crack, Fisura, Riss, Fluorescence induite par laser, Laser induced fluorescence, Fluorescencia inducida por laser, Haute énergie, High energy, Alta energía, Hochenergie, Intensité faisceau, Beam currents, Irradiation électron, Electron irradiation, Irradiación electrón, Matériau amorphe, Amorphous material, Material amorfo, Matériau dur, Hard material, Material duro, Hartstoff, Multicouche, Multiple layer, Capa múltiple, Mehrfachschicht, Phase bêta, Beta phase, Fase beta, Beta Phase, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Transport balistique, Ballistic transport, Transporte balístico, 6180F, Substrat alliage base titane, Amorphous alloy, Ballistic impact property, Electron-beam irradiation, and Surface modification

The objective of this study is to investigate ballistic impact properties of multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation. The mixture of Zr-based amorphous alloy powders and LiF + MgF2 flux powders was deposited on a Ti alloy substrate, and then electron beam was irradiated on this powder mixture to fabricate an one-layered surface alloyed material. On top of this layer, the powder mixture was deposited again and then irradiated with electron beam whose beam current was decreased to fabricate the multi-layered surface alloyed material. In the mixed multi-layered surface alloyed materials fabricated with LM1 alloy powders and LM2 or LM10 alloy powders, the surface region consisted of amorphous phases, together with a small amount of crystalline particles, whereas the center region was complicatedly composed of amorphous phases, crystallized phases, and dendritic β phases. Since the surface region mostly composed of amorphous matrix was quite hard, the alloyed materials sufficiently blocked the travel of a projectile. When cracks formed at the surface region propagated into the center region, the formation of many cracks or debris was accelerated, which could beneficially work for absorbing the ballistic impact energy, thereby leading to the higher ballistic impact properties than the surface alloyed materials fabricated with LM1 or LM2 alloy powders.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Chauffage laser, Laser-radiation heating, Contrainte résiduelle, Residual stresses, Dureté, Hardness, Endommagement, Damage, Fer, Iron, Microdureté, Microhardness, Microstructure, Métal transition, Transition elements, Méthode élément fini, Finite element method, Traitement par laser, Laser assisted processing, Traitement surface, Surface treatments, Finite element, Laser surface treatment, Quantitative, Residual stress, and Thermal damage

This paper gives a comprehensive description of thermal damage introduced by a laser surface treatment (LST) and the possibility to build a quantified damage model. Through experimentation and a finite element (FE) simulation, a deep analysis was carried out on the final microstructure, microhardness and residual stress of specimens subjected to LST under different laser powers. According to the study, the phase-transition-induced microstructure change, which can be reflected by microhardness value, is deemed the essential of thermal damage. Residual stress is another product resulted from the thermal process. A scalar is suggested to have a general description of thermal damage quantitatively, which is supposed to be the function of microhardness, residual stress and the material discontinuity. Its value falls into the range of 0-1. As hardness and residual stress are tightly related to the material strength, further work is expected to detail this model, based on the mechanism of how the hardness features and residual stress affect the material strength, to build a coupled model of thermal damage and strength.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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 de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Alliage base aluminium, Aluminium base alloys, Couche mince, Thin film, Capa fina, Duennschicht, Dureté superficielle, Surface hardness, Dureza superficial, Oberflaechenhaerte, Durée vie fatigue, Fatigue life, Longevidad fatiga, Ermuedungslebensdauer, Endommagement, Damaging, Deterioración, Essai flexion rotative, Rotating beam fatigue test, Ensayo flexión rotativa, Umlaufbiegedauerversuch, Fatigue contact, Fretting fatigue, Fatiga contacto, Kontaktermuedung, Force adhérence, Adhesive strength, Fuerza adherencia, Haftfestigkeit, Microdéplacement, Microdisplacement, Microdesplazamiento, Nitrure de titane, Titanium nitride, Titanio nitruro, Titannitrid, Pulvérisation cathodique, Cathodic sputtering, Pulverización catódica, Kathodenzerstaeubung, Revêtement dur, Hard coating, Revestimiento duro, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Aluminium7075-T6 alloy, Magnetron sputtering, and Titanium nitride coating

Application of surface modification methods is expected to be a supreme solution to diminishing fretting damage. In this study, our aim was to improve the fretting fatigue life of Al7075-T6 alloy by covering it with a TiN thin film hard coating using the magnetron sputtering technique. Coated specimens with the best surface hardness, adhesion strength and roughness were tested with a rotating bending fatigue test machine. The fatigue results indicate that fretting was significantly detrimental and reduced the fatigue life of uncoated specimens, while a slighter decrease was observed for coated samples with high surface hardness and adhesion. The fretting fatigue lives of coated specimens with high surface hardness and adhesion strength improved 61% and 16% at high bending stress and 39% and 77% at low bending stress, respectively, in comparison to the uncoated specimens. In addition, the lowest surface roughness resulting from thin film TiN coating improved the fretting fatigue life of specimens by 18% at low cyclic fatigue, while at high cyclic fatigue the result was reversed.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Trempe et revenu, Hardening. Tempering, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Dureté, Hardness, Acier martensitique, Martensitic steel, Acero martensítico, Martensitischer Stahl, Acier, Steel, Acero, Chauffage laser, Laser heating, Calentamiento láser, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Contrainte traction, Tensile stress, Tensión traccíon, Zugspannung, Dilatation thermique, Thermal expansion, Dilatación térmica, Thermische Ausdehnung, Dilatométrie, Dilatometry, Dilatometría, Dilatometrie, Distribution contrainte, Stress distribution, Campo restricción, Mechanisches Spannungsfeld, Dureté, Hardness, Dureza, Haerte, Dépendance température, Temperature dependence, Etude théorique, Theoretical study, Estudio teórico, Theoretische Untersuchung, Martensite revenue, Tempered martensite, Martensita de revenido, Vergueteter Martensit, Modélisation, Modeling, Modelización, Méthode élément fini, Finite element method, Método elemento finito, Finite Element Methode, Propriété mécanique, Mechanical properties, Propiedad mecánica, Refroidissement, Cooling, Enfriamiento, Kuehlung, Revenu, Tempering, Résultat expérimental, Experimental result, Resultado experimental, Traitement par laser, Laser assisted processing, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, FE, Flash heating, Laser heat treatment, Martensite tempering, and Residual Stresses

The process of tempering a martensitic medium carbon steel was investigated with the aim to study resulting material properties. The experimental results were used to model residual stresses caused by local heating, with the finite element method. Tempering was followed for times from 0.1 s up to 1 h by using laser heating and conventional salt bath furnace treatments within the temperature interval 500―700 °C. In addition, the thermal expansion was evaluated using dilatometry. Experiments showed that the initial stages of martensite decomposition, associated with loss of crystal tetragonality, proceed almost instantly. An initial large decrease of hardness within the first tenth of a second of the tempering process was measured, followed by only limited further softening with increased tempering time. Thus for the current material the tempering time had limited influence on hardness, governed primarily by the peak temperature during the heating process. Finite element modelling of rapid local heating and cooling showed that the tempering behaviour and associated dilatation effects yield a peak temperature dependent residual stress field with a broad tensile stress distribution for the case of un-tempered martensite. However, for tempered martensite the residual stress field depends primarily on the heating rate and peak temperature and shows large gradients with tensile stresses in the surface and compressive below. Thereby, for both cases, residual stresses were obtained but with completely different residual stress gradients.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Traitements de surface, Surface treatments, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Surface treatment, Acier chrome molybdène, Chromium-molybdenum steels, Acier construction, Structural steel, Acero construcción, Baustahl, Affinement grain, Grain refinement, Afino grano, Kornfeinen, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Durcissement solution solide, Solid solution strengthening, Endurecimiento solución sólida, Mischkristallverfestigung, Fusion laser, Laser fusion, Fusión láser, Fusion surface, Surface melting, Fusión superficie, Oberflaechenschmelzen, Grenat aluminium yttrium, YAG, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Gear micropitting, and Laser surface melting

This paper investigates the micropitting behavior of 35CrMo structural steel gears treated through laser surface-melted (LSM) treatment. Laser surface melting of 35CrMo structural steel gears was achieved by a 4.5 kW Nd:YAG pulsed laser with various laser energy densities. The microstructure and the phases present in the LSM gear teeth were analyzed by SEM and XRD. The FZG test rig was used for micropitting experiments. Post-test analysis included the weight loss measurement of gears (pinion and wheel). The micropits on the tooth flanks were inspected using SEM. XRD analytical results showed that martensite is the main phase in the LSM teeth flank. The LSM gears showed better micropitting performance as compared with the as-received one. The improvement in micropitting resistance of the LSM gears is due to grain refinement and solid solution hardening.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Trempe et revenu, Hardening. Tempering, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Rupture, Fractures, Amorçage fissure, Crack initiation, Iniciación grieta, Risseinleitung, Charge cyclique, Cyclic load, Carga cíclica, Zyklische Belastung, Corrosion, Corrosión, Korrosion, Durée vie fatigue, Fatigue life, Longevidad fatiga, Ermuedungslebensdauer, Durée vie rupture, Fracture life, Longevidad rotura, Bruchlebensdauer, Endommagement, Damaging, Deterioración, Essai corrosion, Corrosion test, Ensayo corrosión, Korrosionsversuch, Fatigue, Fatiga, Ermuedung, Fractographie, Fractography, Fractografía, Fraktographie, Grenaillage, Shot peening, Granalla, Kugelstrahlen, Revenu, Tempering, Rupture fatigue, Fatigue fracture, Rotura fatiga, Dauerbruch, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, 8245B, Aluminum alloy shot peening, Fatigue loading, Life and fracture, and Pre-corrosion

Pre-corrosion tests were performed on the high strength aluminum alloy 7050 in the T7451 temper that was subject to shot peening surface treatment. This was done for different time intervals and compared one-on-one with samples of the alloy that were not subjected to shot peening. The shot peening surface treatment was conducted for shot peening intensities of 0.006A and 0.008A. The pre-corrosion test specimens were subsequently subjected to fatigue loading and the resultant life was determined with the prime objective of establishing the intrinsic influence of damage due to corrosion on response of the alloy when subjected to cyclic loading. Fatigue fracture surfaces of the non-shot peened samples that were exposed to the environment and concomitant corrosion revealed crack initiation to occur at the pits. The overall fatigue life of the pre-corroded test specimens that were subject to shot peening was noticeably higher than the non-shot peened counterpart. An increase in shot peening intensity on the sample surface revealed an observable improvement in the fatigue life of this high strength aluminum alloy.

Crystallography, Cristallographie cristallogenèse, Chemical industry parachemical industry, Industrie chimique et parachimique, 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, Formage, Forming, Emboutissage, Deep drawing, Traitements de surface, Surface treatment, Corrosion, Mécanismes fondamentaux et formes de la corrosion, Corrosion mechanisms, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Acier, Steel, Acero, Acrylique acide polymère, Acrylic acid polymer, Acrílico ácido polímero, Corrosion, Corrosión, Korrosion, Couche mince, Thin film, Capa fina, Duennschicht, Diffraction électron rétrodiffusé, EBSD, Diffractión electrón retrodifusa, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Déformation, Deformation, Deformación, Verformung, Dépôt immersion, Dip coating, Depósito inmersión, Tauchbeschichten, Effet environnement, Environmental effect, Efecto medio ambiente, Umgebungseinfluss, Emboutissage, Deep drawing, Estampado, Tiefziehen, Endommagement, Damaging, Deterioración, Fissuration, Cracking, Agrietamiento, Rissbildung, Formabilité, Formability, Formabilidad, Formbarkeit, Image numérique, Digital image, Imagen numérica, Maclage, Twinning, Chocleo, Zwillingsbildung, Microstructure, Microestructura, Mikrogefuege, Polyélectrolyte, Polyelectrolyte, Polielectrolito, Procédé sol gel, Sol gel process, Procedimiento sol gel, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, Zink, 8115L, 8235R, 8245B, Plasticité induite par maclage, Twinning induced plasticity, Substrat acier, Digital image correlation (DIC), Electron backscatter diffraction (EBSD), and PAH/PAA-films

Steels showing twinning-induced plasticity (TWIP) are characterized by extraordinary mechanical properties at room temperature, i.e. high strength and ductility. But at the same time these steels are suffering from environmental effects, leading to surface corrosion and hydrogen related effects. Traditional coatings such as zinc layers may not show sufficient formability, so that local failure of these coatings can occur during forming of sheets, e.g. by deep drawing. Local failure of the coating system will eventually lead to localized corrosive attack, deteriorating the TWIP steel performance. In order to protect the surfaces during processing, a new kind of extremely formable coating for TWIP steels is proposed in this study. Thin polyelectrolyte films are deposited on the TWIP surfaces by a dip coating process. Different film conditions are established and the corresponding damage evolution is characterized. In order to precisely determine the reasons for local film cracking, a thorough characterization of the deformation behavior and the surface evolution of the TWIP steel substrates have been conducted and the suitability of the polyelectrolyte-based coatings for future applications has been demonstrated.