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Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Carbure de titane, Titanium carbide, Titanio carburo, Titancarbid, Décharge étincelle, Spark discharge, Descarga chispa, Frittage réactif, Reaction sintering, Sinterización reactivo, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Plasma, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, SPS, TiC, surface modification, and titanium

Hard TiC coating layer is formed on commercially pure titanium by heat treatment in a Spark Plasma Sintering (SPS) mold filled with graphite powder. The thickness of the TiC coating layer is about 10 μm in case of heat treatment for 3600s at 1243 K and the thickness of this layer is almost uniform. This coating consists of TiC and graphite, and titanium oxide is not detected by X-ray diffractometer (XRD). Vickers hardness test revealed that the hardness of TiC coating was 1600HV, which was much higher than that of titanium substrate (130HV). The hard TiC coating on titanium is considered to have advantage in the applications to load-bearing parts of hard tissue replacements. The growth behavior of TiC is conformed to be parabolic, and the activation energy of growth of TiC is 218.6kJ/mol. This value is close to the activation energy of carbon diffusion in TiC. Therefore, the rate of growth of TiC is controlled by carbon diffusion in TiC phase.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Assemblage et découpage thermique: aspects métallurgiques, Joining, thermal cutting: metallurgical aspects, Soudage, Welding, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Alliage surface, Surface alloying, Aleación superficie, Oberflaechenlegieren, Assemblage mécanique, Mechanical joint, Ensamblaje mecánico, Assemblage soudé, Welded joint, Ensamblaje soldado, Schweissverbindung, Défaut, Defect, Defecto, Fehler, Laser, Láser, Matériaux dissemblables, Dissimilar materials, Materiales desemejantes, Verschiedenartige Werkstoffe, Propriété mécanique, Mechanical properties, Propiedad mecánica, Pénétration soudure, Weld penetration, Penetración soldadura, Einbrand, Soudage laser, Laser welding, Soldeo láser, Laserstrahlschweissen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, dissimilar materials joining, laser welding, mechanical properties of welded joints, weld penetration, and welding defects

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Adhérence, Adhesion, Adherencia, Adhaesion, Alliage base nickel, Nickel base alloys, Alliage binaire, Binary alloy, Aleación binaria, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Elément alliage, Alloying element, Elemento aleación, Legierungselement, Nickel, Niquel, Nickelage, Nickel plating, Niquelado, Vernickeln, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, adhesion, alloying element, binary aluminum alloy, electroless nickel-phosphorus plating, and zincate treatment

Formation of zincate films and adhesion of electroless nickel-phosphorus plated films were studied for binary aluminum alloys of Al-2at%Mn, Al-2at%Fe, Al-2at%Cu, Al-2at%Zn and high-purity aluminum (99.999 mass%). Precipitation mode of zinc in the zincate treatmens greatly varied according to the alloying elements in the substrates. In the cases of the first and the second zincate treatments for Al―Mn, Al―Fe and high-purity aluminum, zinc precipitated excessively, then, porous films of zinc repeatedly fell off the substrate. The surfaces of Al―Cu and Al-Zn alloys were immediately coated by uniform zincate films in the first and the second zincate treatments. Precipitation of zinc is considered to be uniform if the oxide film on a substrate dissolves uniformly and rapidly in the zincate solution. When electroless nickel-phosphorus plating was conducted after the second zincate treatment of Al―Mn and Al-Fe alloys, the plated films easily peeled off. Those on Al―Cu and Al―Zn alloys showed excellent adhesion, and dimple patterns of the substrates were observed on the partly peeled areas. The poor adhesion is thought to be caused because the excess zinc dissolves at the beginning of the plating and generates hydrogen gas, then, gaps are formed between the plated films and the substrates.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Chromate, Chromates, Cromato, Dépôt conversion, Conversion coating, Depósito conversión, Konversionsbeschichten, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, adhesive properties, aluminum alloy, chromate-free, conversion coatings, and magnesiuna alloy

Magnesium is a light metal with high specific strength and electromagnetic shielding properties. In recent years, it is required to adhere magnesium alloys with different metals. Bonding method is one of easy joint process between magnesium alloys and other materials. Contact corrosion of magnesium and different metals can be suppressed by using of adhesive. On the other hand, chromate conversion coating on magnesium was known as carcinogen and one of the methods to limit use of conversion coating. This paper describes the effects of conversion coatings on bond properties of magnesium and aluminum alloys. AZ31B magnesium alloy and A2017, A6022 aluminum alloys were used as specimens. Bond properties were evaluated by pull-off test, bond torque test and tensile lap-shear strength test. In addition, galvanic corrosion was evaluated by salt spray test. As a result of investigation on the bond strength of conversion coatings, the highest bond strength was obtained from the specimen of Mg (OH)2 coat- ing on magnesium alloy and boehmite on aluminum alloy using epoxy resin for cure temperature of 373 K. The Mg(OH), coatingis expected as one of the alternatives of the chromate conversion coating.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Nettoyage. Dégraissage. Décapage, Cleaning. Degreasing. Pickling, Nettoyage surface, Surface cleaning, Limpieza superficie, Oberflaechenreinigen, Recyclage, Recycling, Reconversión, Rueckgewinnung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, laser cleaning, magnesium scraps, and recycling processes

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Propriété mécanique, Mechanical properties, Propiedad mecánica, Anodisation, Anodizing, Anodización, Elektrolytisches Oxidieren, Corrosion piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Diagramme polarisation, Polarization diagram, Diagrama polarización, Polarisationsdiagramm, Déformation plastique, Plastic deformation, Deformación plástica, Plastische Verformung, Pressage, Pressing, Prensado, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Structure grain fin, Fine grain structure, Estructura grano fino, Feinkorngefuege, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, aluminum alloy, anodizing, equal-channel angular pressing, pitting corrosion, and polarization curve

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Fatigue, Alliage base magnésium, Magnesium base alloys, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Fatigue, Fatiga, Ermuedung, Forgeage, Forging, Forja, Schmieden, Formage, Forming, Conformado, Umformen, Grenaillage, Shot peening, Granalla, Kugelstrahlen, Pièce forgée, Forgings, Pieza fraguada, Schmiedestueck, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, fatigue properties, graded structure, magnesium alloy, residual stress, and shot peening

To improve the fatigue properties of AZ31 magnesium alloys, two technical approaches were used to reform the material structure. The first approach is grain refinement of the material structure by multi-axial alternative forging (MAF) to reduce anisotropy and to improve the strength. The second approach created an inclined recrystallized surface layer by shot peening to retard crack initiation on the surface layer and the propagation rate in the tissue layer of the fine-grained structure. The relationship between the microstructures and fatigue properties was examined. As a result, by combining MAF and heat treatment the endurance limit increased by 15%. Moreover, shot peening at medium temperatures formed a recrystallized submicrometer grain size microstructure in the surface layer and an inclined structure to a depth of over 100μm below the surface, and the fatigue properties increased by about 30%. From measurement of the crack propagation rate, it was found that the improvement in fatigue properties led to the delay in crack initiation in the fine-grained surface layer and decreased the crack propagation rate in the residual strained layer.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Corrosion, Corrosión, Korrosion, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Polymère, Polymer, Polímero, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, coating, corrosion, polymer, self-healing, and zirconium

The self-healing corrosion protective properties of polymer coatings for aluminum were investigated. Zirconium phosphate conversion coating and polymer coating, which are various primer and top coatings with a thickness of 5 and 11 μm, were applied to the surface of pure aluminum, and after creating a defect by means of a knife-edge, a corrosion test was carried out in 0.5 mass% NaCl solution at 40°C. The polarization resistance of each coating was measured using electrochemical impedance method to evaluate the self-healing capability of coatings. The polarization resistance of scratched specimen coated polymer containing pigment increased with increasing time, resulting in high resistance. Thus, the self-healing capability of the polymer coating was recognized. The healing film formed on the scratched surface contained carbon. Analyzing component eluted from the coating, diethyl phthalate was detected. Polarization measurement of aluminum substrate in corrosive solution with the organic compound was conducted, and it was confirmed that the organic compound has the inhibiting effect against corrosion. The results showed that the organic compound was related to the formation of healing film.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Poudres métalliques, Metal powders, Métaux et alliages frittés. Cermets, Sintered metals and alloys. Pseudo alloys. Cermets, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Alliage mécanique, Mechanical alloying, Aleación mecánico, Mechanisches Legieren, Apatite hydroxylée, Hydroxyapatite, Hidroxiapatito, Biomatériau, Biomaterial, Dureté, Hardness, Dureza, Haerte, Décharge étincelle, Spark discharge, Descarga chispa, Frittage, Sintering, Sinterización, Sintern, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Plasma, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Titane, Titanium, Titanio, Titan, hardness, hydroxyapatite, mechanical alloying, pure titanium, and spark plasma sintering

Ti-x HAp (x=0, 10, 20 and 30mass%) composite powders were synthesised by mechanical alloying (MA) using a vibrational ball mill, and MAed composite powders were consolidated into bulk composite materials by spark plasma sintering (SPS). The hardness and constituent phase of the MAed powder and SPS materials were investigated by hardness measurements and X-ray diffraction (XRD), respectively. Mean particle size of the MAed powders and microstructure of the SPSed materials were characterised by scanning electron microscopy (SEM) and optical microscopy, respectively. No decomposition of HAp in the MAed Ti-10 and 20 HAp composite powders occurred. However, decomposition of HAp in the MAed Ti-30 HAp composite powders occurred to form both CaO and CaTiO3. Formation of both TiC and CaO was observed in the all SPSed materials. In addition, formation of both CaO and CaTiO3 was also observed in the Ti-30 HAp SPSed materials. The hardness of the SPSed materials increased by both an increase in the amount of HAp and in the MA time. The results thus imply that the Ti-HAp composite materials exhibiting the high hardness can be obtained by a controlling of the amount of HAp powder and MA time.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Ecrouissage, Work hardening, Endurecimiento en frío, Formage presse, Press forming, Conformado prensa, Formpressen, Microstructure, Microestructura, Mikrogefuege, Texture, Textura, Textur, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tôle, Sheet metal, Chapa, Blech, bending, cold working, magnesium alloy sheet, press working, and texture

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Alliage base aluminium, Aluminium base alloys, Apatite hydroxylée, Hydroxyapatite, Hidroxiapatito, Application médicale, Medical application, Aplicación medical, Medizinische Technik, Biomatériau, Biomaterial, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, bioactivity, biomaterial, hydroxyapatite, surface modification, and titanium alloy

Two types of surface modifications such as chemical-hydrothermal and NaOH heat treatments were carried out in Ti-10Cr-0, 3 and 6 Al alloys. The effect of heat treatment accompanied by the modifications on several properties of substrates was also investigated. The Ti alloys were chemically treated with H2O2/HNO3 solutions at 353 K for 2 h. The specimens were then hydrothermally treated with an aqueous Ca(OH)2 in an autoclave at 453 K for 12 h. Homogeneous CaTiO3 films could be obtained on all substrates. On the other hand, TiO2 and Na2TiO3 composite films could be obtained by the NaOH heat treatment. After the chemical-hydrothermal treatment, the hardness of substrates was hardly changed though a small amount of isothermal ω was confirmed to form in Ti-10Cr-0 and 3 Al alloys. In contrast, all the present alloys were hardened due to α phase precipitation after the NaOH treatment. A small amount of hydroxyapatite precipitation could be observed on the non-surface modified substrates after 4 days immersion in simulated body fluid. In contrast, the precipitation was confirmed to occur in only 2 days on the CaTiO3 films. Thus, the combined chemical-hydrothermal treatment promoted the deposition of hydroxyapatite on the surfaces while maintaining the original properties of substrates.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Alliage base aluminium, Aluminium base alloys, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Ecrouissage, Work hardening, Endurecimiento en frío, Eutectique, Eutectic, Eutéctico, Eutektikum, Fonderie, Foundry, Fundería, Giesserei, Formabilité, Formability, Formabilidad, Formbarkeit, Formage, Forming, Conformado, Umformen, Morphologie, Morphology, Morfología, Pressage, Pressing, Prensado, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, AC4CH aluminum casting alloy, equal-channel angular pressing, eutectic Si particle, tensile properties, and work hardening

AC4CH casting alloys were subjected to the 2-step preheating and the ECAP processing at room temperature. Microstructure change was investigated in terms of size and globularity of the eutectic Si particles and hardness of the primary and the eutectic α-Al. The effects of 2-step preheating, ECAP processing and standard T6 heat treatment on the hardness and the tensile properties were also investigated. The results of this study are as follows. The ECAP formability was significantly improved by the optimum 2-step preheating (1st-step preheating at 560°C and 2nd-step preheating at 350°C). More than 12-times ECAP pressing (equivalent strain of about 5.6) could be made without cracking. The hardness distribution in the primary α-Al suggested that the accumulated plastic strain during the ECAP processing increased gradually toward the eutectic cell regions. The hardness measurement also showed that the accumulated plastic strain of the eutectic α-Al around less-globular Si particles was higher than that around globular Si particles. Concentration of the plastic strain may promote cracking in the eutectic cell regions and deteriorate the ECAP formability. Successive processing by the 2-step preheating, the ECAP processing and the standard T6 heat treatment brought about globularity and homogeneous distribution of the eutectic Si particles. During the tensile deformation, these microstructural features might lead to homogeneous distribution of the plastic strain, suppressions of the cracking of Si particles and the delamination between the Si particle and the matrix. As a result, the 0.2% proof stress and the fracture strain increased about 11 % and 47% respectively compared with those of the standard T6 treated sample.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Amortissement, Damping, Amortiguación, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Oxyde anodique, Anodic oxide, Oxido anódico, Revêtement, Coatings, Revestimiento, Ueberzug, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, anodic oxide coating, bonding strength, damping properties, magnesium alloy, and titanium alloy

In this study, effects of the anodizing condition on the bonding strength and the damping properties of the bonding specimen were investigated. The specimens bonded Ti―6Al―4V alloys to AZ31 magnesium alloys with epoxy resin adhesives were used. A porous anodic oxidation film of about 4 μm thickness was formed on the Ti―6Al―4V alloy surfaces by anodizing. The Vickers hardness of anodized Ti―6Al―4V alloy specimen was increased two times higher than that of non-treated specimen. And then, the bonding strength measured by the adhesion tester was also increased. The damping characteristics of bonded specimen were examined through experiments of the collision sound and the reaction velocity of pendulum. As a result, in comparison to the no-treated specimen, the damping performances of anodized Ti―6Al―4V titanium alloy specimens were increased and restitution coefficients of that were decreased. On the other hand, the tonal component of the AZ31 magnesium alloy was reduced in the lower register below 1 kHz. It was also demonstrated that the damping performance of the bonding specimen was improved depending on the anodic oxide coating and adhesive.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Alliage base titane, Titanium base alloys, Apatite hydroxylée, Hydroxyapatite, Hidroxiapatito, Biomatériau, Biomaterial, Dépôt chimique phase vapeur, Chemical vapor deposition, Depósito químico fase vapor, Chemisches Aufdampfen, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Dépôt phase vapeur, Vapor deposition, Depósito fase vapor, Aufdampfen, Elasticité, Elasticity, Elasticidad, Elastizitaet, Fabrication, Manufacturing, Fabricación, Fertigung, Module Young, Young modulus, Módulo Young, Module élasticité, Elastic modulus, Módulo elasticidad, Elastizitaetsmodul, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Young's modulus, hydroxyapatite film, mechanical properties, metal-organic chemical vapor deposition, and β-titanium alloy

A hydroxyapatite (HAp) film was fabricated on the surface of Ti-29Nb-13Ta-4.6Zr (TNTZ) using a metal-organic chemical vapor deposition (MOCVD) technique, and the mechanical biocompatibility and HAp formability of HAp-coated TNTZ were evaluated and discussed in this study. HAp film is fabricated on the surface of TNTZ by controlling the heating temperature of the source bis-dipivaloylmethanatocalcium ( (Ca (dpm)2) and (C6H5O)3PO). An α-phase precipitates in the TNTZ matrix after heating the substrate, and the mechanical properties and Young's modulus of HAp-coated TNTZ are improved. HAp-coated TNTZ maintains excellent mechanical biocompatibility. The formability of HAp on HAp-coated TNTZ in Hank's balanced salt solution is better than that of HAp on non-coated TNTZ.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, Anodisation, Anodizing, Anodización, Elektrolytisches Oxidieren, Corrosion, Corrosión, Korrosion, Essai brouillard salin, Salt spray test, Ensayo en niebla salina, Salzspruehpruefung, Polarisation anodique, Anodic polarization, Polarización anódica, Anodische Polarisation, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Mg―Li―Y alloy, anodic polarization, anodizing, corrosion resistance, salt spray test, and ultra light alloy

Effects of anodizing conditions on corrosion resistance of Mg―Li―Y alloy, which is most prominent super light alloy capable for easy deformation, were investigated with attention to the formation behavior and microstructure of anodic films. Barrier films or semi-barrier films were formed except at around 7 V and breakdown voltages similar to those associated with typical pure magnesium and AZ alloys. At the former voltages, thick porous type films were formed. The critical voltage of high current flow accompanied by breakdown was dependent on substrate composition; 45 V for Mg―Li―Y alloy, 60 V for 99.95% Mg and 120 V for AZ91D. When aluminate or phosphate ion was added in the electrolyte, the critical voltage of Mg―Li―Y alloy increased to 100 V. Lithium was highly enriched at the outer part of the film and yttrium was enriched in the middle to inner part when the film was barrier type. The ratio of barrier film thickness to anodizing voltage was as high as 4.25 nm/V compared to 1.9 nm/V of that associated with 99.95% Mg. When the film was porous type, the content of both lithium and yttrium decreased and distribution of both elements became uniform. Anodic films formed in sodium phosphate solution followed by sealing treatment in silicate exhibited sufficient corrosion resistance for practical usage.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Alliage base aluminium, Aluminium base alloys, Cuivre alliage, Copper alloy, Cobre aleación, Kupferlegierung, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Durcissement précipitation, Precipitation hardening, Endurecimiento precipitación, Ausscheidungshaerten, Ecrouissage, Work hardening, Endurecimiento en frío, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Microstructure, Microestructura, Mikrogefuege, Précipitation, Precipitation, Precipitación, Ausscheidung, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vieillissement, Ageing, Envejecimiento, Altern, Al-Cu-Mg-Si Alloy, T8 temper, precipitation hardening, strength, and work hardening

The effects of 20°C natural aging and 20% cold work on the strength of 2013 aluminum alloy (Al-1.7Cu-1.0Mg-0.8Si-0.15Cr: mass%) aged at 170°C for 8h have been investigated. The strength of T6 samples slightly decreased with increasing the time of natural aging after solution heat treatment. Though the amount of precipitation hardening was lower than T6 specimens, the strength was improved by combination of natural aging and cold working, namely T8 temper. However, cold working just after solution heat treatment resulted in lower precipitation hardening, and thus the T8 strength was lower than that of the specimens with prolonged natural aging after solution heat treatment. It is suggested that the lower precipitation hardening resulted from the heterogeneous distribution of the hardening precipitates formed on the microbands.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, 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, Propriété mécanique, Mechanical properties, Propiedad mecánica, Alliage base magnésium, Magnesium base alloys, Anodisation, Anodizing, Anodización, Elektrolytisches Oxidieren, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Frottement, Friction, Frotamiento, Reibung, Oxydation, Oxidation, Oxidación, Phosphate, Phosphates, Fosfato, Phosphat, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, AZ91D magnesium alloy, anodic oxidation, and friction and wear properties

The effects of various surface treatments on the friction and wear properties of AZ91D magnesium alloy substrate against the SUJ2 steel ball were evaluated by using a horizontal reciprocating friction and wear test apparatus. The friction and wear properties greatly changed due to the type of surface treatment in spite of being under equal friction and wear testing conditions. Wear loss of AZ91D magnesium alloy anodized from the phosphate solution was greatly reduced in comparison with the other surface treatments such as Dow17, conversion coatings and also no surface treatment. The above results suggest that anodizing from the phosphate solution should improve the friction and wear properties of magnesium alloy used for sliding parts.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Activation, Activación, Alliage base nickel, Nickel base alloys, Dépôt chimique, Chemical deposition, Depósito químico, Stromloses Beschichten, Effet composition, Composition effect, Efecto composición, Konzentrationseinfluss, Elément alliage, Alloying element, Elemento aleación, Legierungselement, Nickel, Niquel, Nickelage, Nickel plating, Niquelado, Vernickeln, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, activation, alloying elements, aluminum alloys, electroless nickel-phosphorus plating, and zincate treatment

Zincate treatment and electroless nickel-phosphorus plating for aluminum alloys of A1100, A2017, A5052 and A7075 were researched from the viewpoints of alloying elements and activation conducted prior to zincate treatment. Adhesion strengths of the plated films were measured by 90° peeling test, which showed that double zincate treatment improved adhesion strength especially when ferric ion was added into the zincate solution. Temporal changes of electrode potential during zincate treatments and morphologies of the zincated surfaces showed that copper and zinc in the substrates promoted uniform precipitation of zinc. Excess zinc was shown to dissolve into the plating solution and cause formation of low-density areas or gaps between plated films and substrates. Activation for A1100 by various conditions showed that formation of oxide film remarkably affected the precipitation of zinc. When a mixture of nitric and hydrofluoric acid was used for activation, finer particles of zinc were formed near etch pits compared with the cases of hydrochloric or nitric acid. On the other hand, the surface was uniformly covered with fine zinc particles in the case of the activation with a solution of sodium hydroxide. This indicates that uniformity of oxide film on substrate before zincate treatment is thought to bring about uniform precipitation of zinc.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Etat surface, Surface conditions, Estado superficie, Oberflaechenzustand, Alliage base magnésium, Magnesium base alloys, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, AZ31 magnesium alloy, gloss, metallic luster, surface roughness, and surface treatment

In order to clarify the relationship between the surface roughness and the metallic luster and the relationship between the surface roughness and the conditions of the surface treatment, the surface roughness was examined in AZ31 magnesium alloy. The standard state of the metallic luster was the surface polished by emery paper #2000. The surface roughness and the metallic luster were quantified by the root mean square roughness, σ, with a cutt-off value of 0.002 mm and the specular gloss. It was analyzed the relationship between the metallic luster and the surface roughness. For the result, the metallic luster was available that the surface roughness was formed in the range of 0<σ/λ<0.1, and the necessary value of σ for the realization of the metallic luster was less than 53 nm. The optimal acid aqueous solution treatment was available the metallic luster, and σ was 9 nm. Finally, σ with the surface treatment conditions in the both component included the oxidant and high temperature and in the oxidant-free both components was examined, and was about 80 nm. Therefore, it was concluded that the metallic luster was unavailable.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Autres traitements de surface, Other surface treatments, Corrosion, Action des agents de corrosion, Corrosion environments, Alliage base magnésium, Magnesium base alloys, Anodisation, Anodizing, Anodización, Elektrolytisches Oxidieren, Corrosion, Corrosión, Korrosion, Couche oxyde, Oxide layer, Capa óxido, Oxidschicht, Oxyde anodique, Anodic oxide, Oxido anódico, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, AZ31B magnesium alloy, anodic film, anodizing, corrosion resistance, and sparking

The microstructures and corrosion resistance of the anodic oxide films formed on AZ31B magnesium alloy by anodizing under continuous sparking in alkaline phosphate electrolyte (Na3PO4) were investigated. Basically, voltage-current characteristic of AZ31B in Na3PO4 solution was the same to that obtained in other sodium salt electrolytes such as Na2SiO3 and NaAlO2. However, the anodic films formed in Na3PO4 solution exhibited the higher corrosion resistance than that of the films formed in other electrolytes because of the incorporation of substantial amount of magnesium phosphate. The microstructures (e.g., diameter and number of pores) of the anodic films formed under sparking accompanied by current or voltage oscillation and gas evolution were strongly affected by the degree of sparking such as size, number, and appearance frequency, not by the formation voltage itself. X-Ray diffraction analysis revealed the incorporation of crystalline Mg3 (PO4)2 into the anodic film formed under the sparking condition of dielectric breakdown.