Electrical engineering, Electrotechnique, Energy, Énergie, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Mécanismes fondamentaux et formes de la corrosion, Corrosion mechanisms, Electrolyte polymère, Polymer electrolytes, Acier inoxydable 316, Stainless steel-316, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Cinétique, Kinetics, Cinética, Kinetik, Défaut ponctuel, Point defect, Defecto puntual, Punktfehler, Dégradation, Degradation, Degradación, Electrolyte solide polymère, Polymer solid electrolyte, Electrólito sólido polímero, Endommagement, Damaging, Deterioración, Environnement, Environment, Medio ambiente, Umgebung, Formation film, Film formation, Formación película, Modèle, Models, Modelo, Pile combustible membrane échangeuse proton, Proton exchange membrane fuel cells, Pile combustible électrolyte solide, Solid electrolyte fuel cells, Pile combustible, Fuel cell, Pila combustión, Brennstoffzelle, Résistance contact, Contact resistance, Resistencia contacto, Kontaktwiderstand, Vitesse corrosion, Corrosion rate, Velocidad corrosión, Korrosionsgeschwindigkeit, Plaque bipolaire, Bipolar plate, Bipolar plates, Corrosion rates, PEFC, and Point defect model

A potentiostatic polarization method is used to evaluate the corrosion behavior of SS316L in simulated anode and cathode environments of polymer electrolyte fuel cells. A passive barrier oxide film is observed to form and reach steady state within ~10 h of polarization, after which time the total ion release rates are low and nearly constant at ~0.4 μg cm-2 h-1 for all potentials investigated. The equilibrium film thickness, however, is a function of the applied potential. The main ionic species dissolved in the liquid are predominately Fe followed by Ni, that account for >90% of the steady-state corrosion current. The dissolution rate of Cr is low but increases systematically at potentials higher than 0.8 V. The experimental ion release rates can be correlated with a point defect model using a single set of parameters over a broad range of potentials (0.2―1 V) on the cathode side. The interfacial contact resistance measured after 48 h of polarization is observed to increase with increase in applied potential and can be empirically correlated with applied load and oxide film thickness. The oxide film is substantially thicker at 1.5 V possibly because of alteration in film composition to Fe-rich as indicated by XPS data.

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, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Structure et morphologie; épaisseur, Structure and morphology; thickness, Propriétés physiques non électroniques de couches minces, Physical properties of thin films, nonelectronic, Propriétés mécaniques et acoustiques, Mechanical and acoustical properties, Acier inoxydable 316L, Stainless steel-316L, Adhérence, Adhesion, Alliage base nickel, Nickel base alloys, Article synthèse, Reviews, Couche mince amorphe, Amorphous thin film, Capa fina amorfa, Couche mince métallique, Metallic thin films, Couche mince, Thin films, Durée vie, Lifetime, Déformation, Deformation, Epaisseur couche, Layer thickness, Espesor capa, Etude expérimentale, Experimental study, Etude théorique, Theoretical study, Flexion, Bending, Instabilité, Instability, Matériau revêtu, Coated material, Material revestido, Méthode élément fini, Finite element method, Propriété mécanique, Mechanical properties, Revêtement, Coatings, Résistance corrosion, Corrosion resistance, Simulation numérique, Digital simulation, Tribologie, Tribology, Verre métallique, Metallic glasses, 4335N, 6855J, 6860B, Substrat verre, Coating, Fatigue lifetime, Fatigue-crack initiation, Finite-element model, and Thin-film metallic glass (TFMG)

Amorphous metallic films, a thin form of metallic glasses, have been attracting more and more attentions in the last two decades, due to their unique properties, compared with the conventional crystalline films, such as high strength, high toughness, large elastic limits, and high-corrosion resistance. However, the deformation mechanisms of thin-film metallic glasses (TFMGs) are still far from in-depth understanding, although some of their properties and characteristics are not as good as metallic or ceramic films. This paper will focus on reviewing and discussing the fatigue behavior of structural-material substrates coated with TFMGs. The substrates include 316L stainless steel, Al-based, Ni-based, Zr-based, and Ti-based alloys. The results show that the four-point-bending fatigue life of the substrates is greatly improved by Zr- and Cu-based TFMGs, while Fe-based TFMG, TiN, and pure-Cu films are not so beneficial in extending the fatigue life of 316L stainless steel. In comparison, the tension-tension fatigue lifetime and endurance limit of 316L stainless steel cannot be improved by the Zr- and Cu-based TFMGs. However, the TFMGs annealed at a temperature within the supercooled liquid region (ΔT) can further improve the fatigue behavior, compared to as-deposited TFMGs. The fatigue mechanisms of crystalline and bulk metallic glass (BMG) materials, together with TFMGs, are reviewed in the present work. Crystals and BMGs present 3-stage and 4-stage fatigue-deformation mechanisms, respectively. The fatigue life of medium-strength structural materials tends to be significantly improved by TFMGs. A synergistic experimental/theoretical study has shown the micro-mechanisms of the fatigue behavior of TFMGs adhered to substrates, as well as film-adhesion and thickness effects on fatigue behavior of the substrate. Furthermore, shear-band initiation and propagation under bending deformation are investigated using the Rudnicki-Rice instability theory and the free-volume models employing finite-element simulations.

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, Ecrouissage, durcissement par déformation; recuit, trempe, revenu, restauration et recristallisation; textures, Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures, Elasticité et anélasticité, Elasticity and anelasticity, 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, Rupture, Fractures, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Champ déformation, Strain distribution, Campo deformación, Charge dynamique, Dynamic load, Carga dinámica, Dynamische Belastung, Distribution contrainte, Stress distribution, Campo restricción, Mechanisches Spannungsfeld, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Déformation dent de scie, Serrated yielding, Dépendance température, Temperature dependence, Essai traction, Tension test, Ensayo tracción, Zugversuch, Fragilisation hydrogène, Hydrogen embrittlement, Fragilización hidrógeno, Wasserstoffversproedung, Haute température, High temperature, Alta temperatura, Hochtemperatur, Onde contrainte, Stress wave, Onda tensión, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Prétraitement, Pretreatment, Pretratamiento, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, Sensibilité vitesse déformation, Strain rate sensitivity, Sensibilidad velocidad deformación, Dehngeschwindigkeitsempfindlichkeit, Vieillissement aprés écrouissage, Strain ageing, Envejecimiento mecánico, Reckalterung, 8140E, 8140J, Ferrous alloy, Mechanical characterization, and Steel

We examined the high-temperature tensile properties of 316L austenite stainless steel (SS) cathodically charged with hydrogen (H) and discussed how the H distribution, strain rate, and temperature range affected the mechanical properties of 316L SS at elevated temperatures, with particular focus on dynamic strain aging (DSA). A preheat treatment was applied prior to each high-temperature tensile test to lessen the H gradient on the outer surface of the specimen. DSA, manifested by serrations in the stress-strain curve, was observed at temperatures between 400 and 500 °C and was analyzed using strain-rate sensitivity, dynamic strain-hardening stress, and the temperature dependence of critical serration strain. In particular, this study confined its scope to the influence of H in the range of a few tens of parts per million.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, 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, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acier inoxydable, Stainless steels, Efficacité, Efficiency, Microdureté, Microhardness, Projection HVOF, HVOF spraying, Proyeccion HVOF, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Traitement surface, Surface treatments, Deposition efficiency, High pressure HVOF, and Stainless steel coating

The High-Velocity Oxy-Fuel (HVOF) technology has been widely used to deposit cermet, metals, and alloy coatings. However, the high temperature and oxidative flame jet results in oxidation and decomposition of spray particles during the spraying process; giving significant influence on phase composition, microstructure, properties, and performance of the sprayed coatings. In this paper, a high pressure HVOF system with a combustion chamber pressuring up to 3.0 MPa along with characteristics of lower flame temperature and higher flame velocity was used to deposit Stainless Steel 316L coatings. Particle velocity was measured by using the DPV-2000 system. It was found that higher combustion chamber pressure enables higher particle velocity. The influence of oxygen/ fuel ratio and spray distance on deposition efficiency, coating microstructure, and micro hardness of the Stainless Steel 316L was investigated. It shows that the oxygen/fuel ratio has a significant influence on particle's melting state. Therefore, dense Stainless Steel 316L coating composed of semi-molten or solid state particles can be obtained by adjusting the oxygen/fuel ratio at the combustion chamber pressure of 3.0 MPa. In the experiment, deposition efficiency up to 90% was achieved at the optimized spray conditions. As a typical conventional HVOF system of JP-5000, the comparison to the JP-5000 sprayed coating was also performed.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Corrosion eau mer, Sea water corrosion, Corrosión agua mar, Meerwasserkorrosion, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Impédance, Impedance, Impedancia, Passivation, Pasivación, Passivierung, Passivité, Passivity, Pasividad, Passivitaet, AISI 316L stainless steel, Mott-Schottky analysis, electrochemical impedance spectroscopy, passive films, and volcanic eruption

This work studies the semiconducting behavior of passive films formed on AISI 316L (UNS S31603) in two different seawater solutions, non-polluted and polluted, collected from the volcano of El Hierro Island. Polarization measurements, potentiostatic passivation tests, electrochemical impedance spectroscopy, and capacitance measurements were performed. Results show that the polluted seawater worsens passivation kinetics. Additionally, passive films formed on AISI 316L stainless steel in polluted seawater have been found to be less protective than those formed in non-polluted seawater, showing a more defective structure, owing to the acidity of the polluted medium.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, 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, Frottement. Usure, Contact of materials. Friction. Wear, Acier inoxydable 316L, Stainless steel-316L, Conception assistée, Computer aided design, Concepción asistida, Corrosion piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Corrosion sel, Salt corrosion, Corrosión sal, Salzkorrosion, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Frottement sec, Dry friction, Frotamiento seco, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Tribologie, Tribology, Tribología, Usure glissement, Sliding wear, Desgaste deslizamiento, Gleitverschleiss, Vitesse usure, Wear rate, Velocidad desgaste, Fusion sélective par laser, Selective laser melting, corrosion, selective laser melting, stainless steel, tribology, and wear

Stainless steel is one of the most popular materials used for selective laser melting (SLM) processing to produce nearly fully dense components from 3D CAD models. The tribological and corrosion properties of stainless steel components are important in many engineering applications. In this work, the wear behaviour of SLM 316L stainless steel was investigated under dry sliding conditions, and the corrosion properties were measured electrochemically in a chloride containing solution. The results show that as compared to the standard bulk 316L steel, the SLM 316L steel exhibits deteriorated dry sliding wear resistance. The wear rate of SLM steel is dependent on the vol.% porosity in the steel and by obtaining full density it is possible achieve wear resistance similar to that of the standard bulk 316L steel. In the tested chloride containing solution, the general corrosion behaviour of the SLM steel is similar to that of the standard bulk 316L steel, but the SLM steel suffers from a reduced breakdown potential and is more susceptible to pitting corrosion. Efforts have been made to correlate the obtained results with porosity in the SLM steel.

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, 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 inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Effet dimensionnel, Size effect, Efecto dimensional, Groesseneffekt, Epaisseur, Thickness, Espesor, Dicke, Essai poinçonnage, Punching test, Prueba punzonado, Essai traction, Tension test, Ensayo tracción, Zugversuch, Grosseur grain, Grain size, Grosor grano, Korngroesse, Limite élasticité, Yield strength, Límite elasticidad, Streckgrenze, Méthode résistance limite, Ultimate strength method, Método resistencia límite, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété volume, Bulk properties, Texture, Textura, Textur, 6220D, 8140G, 316L austenitic stainless steel, Size effects, and Small punch test

The miniature specimen test technique has been extensively studied for quantifying the properties of bulk materials with greatly reduced volume recently. In this paper small punch test (SPT) is used to evaluate effects of specimen thickness, grain size and thickness-to-grain size ratio (TGR) on mechanical properties of 25 samples of type 316L austenitic stainless steel with nearly the same crystallographic texture. Effective SPT yield and maximum loads were measured and correlated with yield and ultimate strengths of conventional tensile test. The results show that SPT is sensitive not only to grain size, but also to thickness and TGR. Size effects exist between SPT and standard-sized samples. The present work gives a size effect criterion of SPT for engineering application. In addition, the underlying mechanisms of these size effects are provided.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Formage, Forming, Acier inoxydable 316L, Stainless steel-316L, Echelle nanométrique, Nanometer scale, Epaisseur, Thickness, Espesor, Dicke, Grosseur grain, Grain size, Grosor grano, Korngroesse, Laminage à froid, Cold rolling, Laminado en frío, Kaltwalzen, Microstructure, Microestructura, Mikrogefuege, Métallographie, Metallography, Metalografía, Metallographie, Nanostructure, Nanoestructura, Recristallisation, Recrystallization, Recristalización, Rekristallisation, Recuit, Annealing, Recocido, Gluehen, Rugosité, Roughness, Rugosidad, Rauhigkeit, annealing, rolling, rough rolls, and surface nanograins

316L stainless steel plates of 5-mm thickness, normalized at 900 °C, were cold rolled with different reductions and number of passes using rolls with three different surface roughnesses: grain heights of 0.17 and 0.33 mm and rhomboid-shaped grains of 1.5-mm height. Subsequently, the rolled samples were annealed at 275 °C for 1 h in an effort to achieve superficial nanograins. The plates laminated using low-roughness rolls had continuous superficial microcrystallization when they were rolled for at least 26 passes. For samples made with rougher rolls, the recrystallized superficial grains formed on the surface (sized ~10-15 μm) were smaller than those below the surface; this behavior was caused by the major deformation induced by repeated indentations. The superficial recrystallization of the sample also tended to be more continuous for higher number of passes; micrographs of the penetration profiles of indentation in the samples rolled with high-roughness rolls revealed that a sample rolled 24 times had not yet reached the steady surface topology. As a conclusion, in order to successfully form superficial nanograins, very low-roughness rolls must be used as well as a small absolute reduction per pass, followed by annealing. These rolling conditions generate a continuous field of highly superficial deformations, which act as nucleation centers for nanograins during annealing.

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, Généralités, General, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Croissance grain, Grain growth, Crecimiento grano, Kornwachstum, Fil métallique, Wire, Hilo metálico, Draht, Microstructure, Microestructura, Mikrogefuege, Recristallisation, Recrystallization, Recristalización, and Rekristallisation

Recrystallization and grain growth behaviors of 316L stainless steel wires with a diameter of 12 μm were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), and X-ray diffraction techniques. Heavily cold-drawn wires were isothermally held at temperatures from 1073 K to 1223 K (800 °C to 950 °C) for various holding times. Optical microscopy and TEM observations showed that recrystallization grains have irregular shape and that twins exist. The texture formed during drawing and annealing processes of the wires, as measured by X-ray methods, showed a fiber texture approximated by a 〈111〉 and a (100) component. The value of the grain growth exponent n was calculated, and the kinetic rates were plotted using the Arrhenius equation. Results show that the activation energy of the grain growth for 316L stainless steel wire was determined to be 407 kJ/mol, which was much higher than that of the bulk 316L stainless steel. The small wire diameter and the existence of texture played important roles in the increase of the activation energy for grain growth of the wire.

Crystallography, Cristallographie cristallogenèse, Electronics, Electronique, Electrical engineering, Electrotechnique, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Matériel électrique divers, Various equipment and components, Electroaimants, Electromagnets, Acier inoxydable 316L, Stainless steel-316L, Alliage base niobium, Niobium base alloy, Aleación base niobio, Cryogénie, Cryogenics, Criogenia, Electroaimant supraconducteur, Superconducting magnet, Electroimán supraconductor, Etain alliage, Tin alloy, Estaño aleación, Etat supercritique, Supercritical state, Estado supercrítico, Hélium, Helium, Helio, Perte charge, Pressure drop, Pérdida carga, Système refroidissement, Cooling system, Sistema enfriamiento, Conducteur câble en conduit, Cable in conduit conductors, CICC, and Nb3Sn

In order to test the performance of experimental advanced superconducting tokamak (EAST) central solenoid (CS) model coil, which was made by the cable-in-conduit conductor using Nb3Sn strands and a 316 L stainless steel jacket, a cryogenic experiment system was designed. The experimental results showed that the superconducting magnet was cooled down to 5 K, which could meet the test requirements successfully. Meanwhile, we measured the pressure drop in CICC of Nb3Sn superconducting magnet under the circulating mode of forced flow cooling which used supercritical helium as coolant compared with the result calculated by the Katheder fraction factor correlation, it showed that calculated pressure drop underestimates the experimental data. We corrected the Katheder correlation and compared with the experimental data, it proved that the corrected correlation is much more suitable for the kind of CICC of Nb3Sn superconducting magnet.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, 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, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable, Stainless steels, Dépôt projection, Spray coatings, Plasma, Projection plasma, Plasma arc spraying, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Traitement surface, Surface treatments, Penetration treatments, Plasma sprayed, and SUS316L stainless steel coating

A study of the effects of penetration treatments on plasma sprayed SUS316L stainless steel coatings was performed. The stainless steel coatings were sealed using multi-component oxides introduced at the conditions of 1273 K for 20 min, 1273 K for 45 min and 1373 K for 45 min. The effectiveness of the penetration was determined using an electron probe microanalyzer (EPMA). The results indicated that the molten multi-component oxides could seal the open pores near the stainless steel coating surface quickly and effortlessly due to the good wettability. The molten multi-component oxides could pass through the oxide path connected to the inter micro-pores smoothly and infiltrated into the stainless steel coating when the period of impregnation was prolonged to 45 min. The penetration became more effective with increasing temperature because of the reactions between the molten multi-component oxides and the original oxides that occurred in the stainless steel coating around the inter pores. The results of a salt spray test indicated that the penetration treatment could significantly improve the corrosion resistance of the stainless steel coating.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Acier austénitique, Austenitic steel, Acero austenítico, Austenitischer Stahl, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Corrosion, Corrosión, Korrosion, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Microscopie force atomique, Atomic force microscopy, Microscopía fuerza atómica, Nanostructure, Nanoestructura, Passivation, Pasivación, Passivierung, Passivité, Passivity, Pasividad, Passivitaet, Spectrométrie photoélectron, Photoelectron spectrometry, Espectrometría fotoelectrón, ESCA Spektrometrie, A. Stainless steel, B. AFM, B. XPS, C. Passive films, and C. Passivity

The passive behavior of a bulk nanostructured 316L austenitic stainless steel consisting of nanometer-sized grains (NG) and nano-twin bundles (NT) are investigated. The electrochemical results indicate that the spontaneous passivation ability and growth rate of passive film are improved. The X-ray photoelectron spectroscopy (XPS) shows that a Cr0-enriched layer forms at the passive film/metal interface. More nucleation sites afforded by the nanostructures and the enhanced diffusion rate of charged species across the passive film are believed to be responsible for the improved passive ability. The PDM model is introduced to elaborate the microscopic process of passivation.

Metallurgy, welding, Métallurgie, soudage, 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, Acier inoxydable 316L, Stainless steel-316L, Angle inclinaison, Tilt angle, Angulo inclinación, Finissage surface, Surface finishing, Modèle statistique, Statistical model, Modelo estadístico, Optimisation, Optimization, Optimización, Optimierung, Rugosité, Roughness, Rugosidad, Rauhigkeit, Texture surface, Surface texture, Fusion sélective par laser, Selective laser melting, Refusion laser, Laser remelting, re-melting, selective laser melting, and surface roughness

In this work, the effects of re-melting parameters for postprocessing the surface texture of Additively Manufactured parts using a statistical approach are investigated. This paper focuses on improving the final surface texture of stainless steel (316L) parts, built using a Renishaw SLM 125 machine. This machine employs a fiber laser to fuse fine powder on a layer-by-layer basis to generate three-dimensional parts. The samples were produced using varying angles of inclination in order to generate range of surface roughness between 8 and 20 μm. Laser re-melting (LR) as post-processing was performed in order to investigate surface roughness through optimization of parameters. The re-melting process was carried out using a custom-made hybrid laser re-cladding machine, which uses a 200 W fiber laser. Optimized processing parameters were based on statistical analysis within a Design of Experiment framework, from which a model was then constructed. The results indicate that the best obtainable final surface roughness is about 1.4 μm ± 10%. This figure was obtained when laser power of about 180 W was used, to give energy density between 2200 and 2700 J/cm2 for the re-melting process. Overall, the obtained results indicate LR as a post-build process has the capacity to improve surface finishing of SLM components up to 80%, compared with the initial manufactured 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, 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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acier inoxydable, Stainless steels, Croissance grain, Grain growth, Dissipation énergie, Energy dissipation, Disipación energía, Déformation à chaud, Hot deformation, Deformación en caliente, Warmverformung, Dépendance température, Temperature dependence, Grosseur grain, Grain size, Haute température, High temperature, Alta temperatura, Hochtemperatur, Instabilité, Instability, Microstructure, Modèle dynamique, Dynamic model, Modelo dinámico, Propriété mécanique, Mechanical properties, Recristallisation dynamique, Dynamical recrystallization, Recristalización dinamica, Dynamische Rekristallisation, Traitement matériau, Material processing, Tratamiento material, Travail à chaud, Hot working, Vitesse déformation, Strain rate, 8140E, DRX, and Processing map

In the present study, the dynamic recrystallization (DRX) behavior of a nitrogen enhanced 316L(N) stainless steel (with 0.14 wt% N) has been studied in the temperature range of 1073-1423 K and strain rate range of 0.001-10 s-1 to understand the correlations between dynamic softening phenomena and efficiencies of hot working domains in the processing map. DRX fractions and the grain sizes in each condition were evaluated to develop DRX map and to study the grain growth. It was observed that the efficiency peaks of the stable domains are associated with increase in DRX fraction in the low temperature domain, increase in both DRX fraction and grain size at the medium temperature domain, and increase in grain size after saturation of DRX in the high temperature domain. Microstructures corresponding to high temperature unstable domain did not reveal any sign of conventional instabilities, instead show substantial amount of DRX grains. However, with increase in thermal energy neither a measurable increase in DRX fraction nor grain growth was observed. This mismatch between the energy input (through increase in temperature) and energy dissipation (through metallurgical phenomena) fulfills the instability criterion of dynamic materials model in this domain.

Mechanical engineering, Génie mécanique, Materials, Matériaux, Metrology and instrumentation, Métrologie et instrumentation, 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, Elasticité. Plasticité, Elasticity. Plasticity, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Conception, Design, Diseño, Gestaltung, Modélisation, Modeling, Modelización, Méthode Bayes, Bayes methods, Méthode itérative, Iterative method, Método iterativo, Méthode résistance limite, Ultimate strength method, Método resistencia límite, Optimisation, Optimization, Optimización, Optimierung, Réseau neuronal, Neural network, Red neuronal, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, Artificial neural network, Bayesian framework, Integrated materials and products design, Materials design, and Modeling uncertainty

Integrated Materials and Products Design (IMPD) is a new system-based design approach. This emerging method focuses on designing a product and its materials at the same time to further enhance product performances. In the process of IMPD, material models that predict material properties with given inputs of material processing parameters play an important role in numerous design optimization iteration loops. In this work, a material model for predicting the tensile strength of austenitic stainless steels is developed based on the neural network with Bayesian framework. Using the Bayesian framework, we quantify the degree of uncertainty, originated from lack of data or the architecture of employed neural network, in the prediction of material properties. This quantification is very important for the later use in robust design optimization. Developed material model is validated based on the two different types of austenitic stainless steels, AISI 316L and AISI 347H, subjected to prior heat treatment processes. Comparing the predicted results with experimental results, we observe our material model predicts the tensile strengths of AISI 316L steels heat-treated at various temperatures with higher levels of accuracy. The predicted tensile strengths of AISI 347H steels tested at different temperatures are reasonably close to the experimental results.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Action des agents de corrosion, Corrosion environments, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Corrosion eau, Water corrosion, Corrosión agua, Wasserkorrosion, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Couche superficielle, Surface layer, Capa superficial, Oberflaechenschicht, Haute température, High temperature, Alta temperatura, Hochtemperatur, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Multicouche, Multiple layer, Capa múltiple, Mehrfachschicht, Oxydation, Oxidation, Oxidación, Température, Temperature, Temperatura, Temperatur, corrosion, crevice, high-temperature water, oxidation, stainless steel, surface oxide layer, and transmission electron microscopy

Surface oxide layers were formed within crevices of Type 316L (UNS S31603) stainless steels in pure water at 288°C and 8 MPa. Cross-sectional structures of the surface oxides were analyzed using transmission electron microscopy. In the condition of dissolved oxygen concentration of 2 ppm, the properties of the surface oxide layer changed with position and dual- or triplex-layered oxides were formed at a certain distance from the crevice mouth. The multilayered oxides were composed of Fe-based oxide in the core and a high-Cr content in the outer layer, which had not been observed on a boldly exposed surface. On the contrary, in deaerated conditions, the surface oxide layers were composed of a magnetite (Fe3O4)-based outer and a Cr-enriched inner oxide layer, regardless of the crevice position. Electrochemical condition within the crevice was identified by using a E―pH diagram. It was suggested that, at 400 μm distance from the crevice mouth, the potential lowered at the early stage of exposure, and then shifted to the noble direction with a decrement of pH. Consequently, even within a narrow crevice with a gap size of a few μm, the uniqueness of the crevice electrochemistry, characterized by the position and time dependence of both the potential and the pH, has been exhibited.

Mechanical engineering, Génie mécanique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, 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, Fatigue, Acier inoxydable 316L, Stainless steel-316L, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Charge multiaxiale, Multiaxial load, Carga multiaxial, Fatigue oligocyclique, Low cycle fatigue, Fatiga oligocíclica, Ermuedung bei niedrigen Lastspielzahlen, Plasticité, Plasticity, Plasticidad, Plastizitaet, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rochet, Ratchetting, Trinquete, Cyclic plasticity, Damage criterion, Multiaxial fatigue, and Ratcheting

To investigate the material behavior of a stainless steel grade AISI 316L, subjected to loading conditions typical for the primary cooling circuit of a light water nuclear reactor, a set of uniaxial, torsional and multiaxial low cycle fatigue and strain-controlled ratcheting tests has been carried out. The main goal of these experiments is to analyze how the cyclic deformation response is influenced by strain amplitudes, loading paths and ratcheting, and to estimate how fatigue life is affected by these elements. Finally, the performance of three advanced multiaxial fatigue criteria (i.e. Smith-Watson-Topper, Fatemi-Socie and Jiang) has been critically evaluated for all the considered loading cases.