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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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Métaux et alliages frittés. Cermets, Sintered metals and alloys. Pseudo alloys. Cermets, Traitements de surface, Surface treatment, 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, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Corrosion électrochimique, Electrochemical corrosion, Corrosión electroquímica, Elektrochemische Korrosion, Frittage, Sintering, Sinterización, Sintern, Microstructure, Microestructura, Mikrogefuege, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, Corrosion, and Intermetallics

An erbium modified Mg17Al12 based coating was fabricated by hot press sintering on as extruded AZ61 Mg alloy. The Er modified coating was composed of Mg17Al12 and Al3Er phases. As a result of the presence of the dispersed Al3Er phase, the coating had a greater microhardness than Mg17Al12. Thermal effects of sintering at 400°C for 1 h caused no obvious deterioration in the wear resistance of the AZ61 Mg matrix. Electrochemical and wear resistance tests showed that the Er modified Mg17Al12 based coating had a lower corrosion current density and a lower friction coefficient than Mg17Al12, the AZ61 Mg matrix and a thermal diffusion coating (TDC). The superior wear resistance of the sintered coating resulted from the hard Al3Er phase. The corrosion resistance of the sintered coating was better than that of the TDC as a result of suppression of hydrogen evolution by the rare earth metal Er.

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, 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, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement, Coatings, Revestimiento, Ueberzug, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, iron alloys, residual stress, robot, and wear resistance

Even though the application of thermal spray coatings on complex geometries gained a greater interest in the last decade, the effect of different geometrical features on the wear behavior is still ill-defined. In this study, the wear resistance of FTC-FeCSiMn coated 3D surfaces was investigated. The wear test was carried out by means of two innovative testing procedures. The first test is a Pin-on-Tubes test where the rotating motion is realized by a lathe chuck. The specimens in the second test were fixed on the table and a robot arm operated the pin. This wear test was applied on specimens with concave or convex surfaces. The residual stresses, which were determined by means of an incremental hole-drilling method, show a dependency on the substrate geometry. The obtained stresses were put in relation to the different radii. After the wear test, a 3D-profilometer determined the wear volume and the sections of the coatings were characterized by a scanning electron microscope. The results indicate that the wear resistance is strongly influenced by the geometry of the substrate.

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, Dépôt de métaux et d'alliages, Metallic coatings, 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, Adhérence, Adhesion, Adherencia, Adhaesion, Application, Aplicación, Anwendung, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Erosion, Erosión, Force adhérence, Adhesive strength, Fuerza adherencia, Haftfestigkeit, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Turbine gaz, Gas turbine, Turbina gas, Gasturbine, Usure, Wear, Desgaste, Verschleiss, MCrAlY, abradable coating, adhesive strength, atmospheric plasma spray (APS), erosion resistance, gas turbines, and rubbing wear

The processing conditions, microstructural and tribological characterizations of plasma-sprayed CoNiCrAlY-BN high temperature abradable coatings are reported in this manuscript. Plasma spray torch parameters were varied to produce a set of abradable coatings exhibiting a broad range of porosity levels (34-62%) and superficial Rockwell hardness values (0-78 HR15Y). Abradability tests have been performed using an abradable-seal test rig, capable of simulating operational wear at different rotor speeds and seal incursion rates (SIRs). These tests allowed determining the rubbing forces and quantifying the blade and seal wear characteristics for slow and fast SIRs. Erosion wear performance and ASTM C633 coating adhesion strength test results are also reported. For optimal abradability performance, it is shown that coating hardness needs to be lower than 70 and 50 HR15Y for slow and fast blade incursion rate conditions, respectively. It is shown that the erosion wear performance, as well as, the coating cohesive strength is a function of the coating hardness. The current results allow defining the coating specifications in terms of hardness and porosity for targeted applications.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Adhérence, Adhesion, Adherencia, Adhaesion, Alumine, Alumina, Alúmina, Tonerde, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Haute résolution, High resolution, Alta resolucion, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Mécanisme formation, Formation mechanism, Mecanismo formacion, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Revêtement, Coatings, Revestimiento, Ueberzug, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, HRTEM, adhesion, alumina, aluminum, cold gas spraying (CGS), and tensile strength

The metallization of ceramics by means of cold gas spraying (CGS) has been in the focus of numerous publications in the recent past. However, the bonding mechanism of metallic coatings on non-ductile substrates is still not fully understood. Former investigations of titanium coatings deposited on corundum revealed that a combination of recrystallization induced by adiabatic shear processes and hetero-epitaxial growth might be responsible for the high adhesion strengths of coatings applied on smooth ceramic surfaces. In the present work, the interface formation between CGS aluminum and alumina substrates is examined for different particle sizes and substrate temperatures. Furthermore, the influence of subsequent heat treatment on tensile strength and hardness is investigated. The splat formation of single particles is examined by means of scanning electron microscopy, while a high resolution transmission electron microscope is used to study the Al/Al2O3 interface. First results suggest that mechanical interlocking is the primary adhesion mechanism on polycrystalline substrates having the roughness in sub-micrometer range, while the heteroepitaxy between Al and Al2O3 can be considered as the main bonding mechanism for single-crystalline sapphire (α-Al2O3) substrates with the surface roughness in nanometer range. The heteroepitaxial growth is facilitated by deformation-induced recrystallisation of CGS aluminum.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Condition opératoire, Operating conditions, Condición operatoria, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Grosseur grain, Grain size, Grosor grano, Korngroesse, Microstructure, Microestructura, Mikrogefuege, Nanocomposite, Nanocompuesto, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, cold spray, mechanical properties, microstructural behavior, nanocomposites, and processing parameters

Cold spray is a coating technology based on aerodynamics and high-speed impact dynamics. In this process, spray particles (usually 1-50 μm in diameter) are accelerated to a high velocity (typically 300-1200 m/s) by a high-speed gas (pre-heated air, nitrogen, or helium) flow that is generated through a convergent-divergent de Laval-type nozzle. A coating is formed through the intensive plastic deformation of particles impacting on a substrate at a temperature below the melting point of the spray material. In the present paper the main processing parameters affecting the microstructural and mechanical behavior of metal-metal cold spray deposits are described. The effect of process parameters on grain refinement and mechanical properties were analyzed for composite particles of Al-Al2O3, Ni-BN, Cu-Al2O3, and Co-SiC. The properties of the formed nanocomposites were compared with those of the parent materials sprayed under the same conditions. The process conditions, leading to a strong grain refinement with an acceptable level of the deposit mechanical properties such as porosity and adhesion strength, are discussed.

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, 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, Corrosion, Corrosión, Korrosion, Elasticité, Elasticity, Elasticidad, Elastizitaet, Indentation, Indentación, Microstructure, Microestructura, Mikrogefuege, Module Young, Young modulus, Módulo Young, Module élasticité, Elastic modulus, Módulo elasticidad, Elastizitaetsmodul, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, MAO, Magnesium, Nanohardness, Nanoindentation, and Young's modulus

The micro arc oxidation (MAO) process is one of the most industrially accepted, prospective methods to design and develop microstruturally integrated, intrinsically generated oxide/ceramic coating over Mg alloys. Here we report, the surface engineering of AZ31 Mg alloy to form MAO coatings by silicate and phosphate based electrolytes. The microstructural examinations of the MAO coatings were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. Further, the nanoindentation studies revealed that the MAO coatings had nanohardness (H) and Young's modulus (E) values as high as about 3―7 times and 1·5―2·5 times those of the as received AZ31 Mg alloy respectively. Both H and E values gradually increased from virgin Mg substrate end to the surface coating end. Further, sealing by hot water did not affect the H and E values of the MAO coatings.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Modélisation, Modeling, Modelización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rupture, Ruptura, Bruch, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, Cold spraying, Critical velocity, and Impact behaviour

Cold spraying (CS) is a coating technique, which has developed rapidly in the last two decades and shows great potential in the industrial community due to its advantages of low temperature deposition as well as no oxides forming in the coating. This review's focus is on the behaviour of particles impacting and the prediction of critical velocity for particle deposition during CS as calculated by numerical simulations according to the open literature. The first part presents an introduction of CS and its particle bonding mechanism. The second part briefly introduces the typically employed numerical computation methods and compares these methods. The third part discusses the effect of particle parameters on particle deformation behaviour. Finally, the current problems and prospects existing in numerical simulations of the impact of CS particles are explored.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Abrasif, Abrasives, Abrasivo, Schleifmittel, Alliage base nickel, Nickel base alloys, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Microstructure, Microestructura, Mikrogefuege, Nanocomposite, Nanocompuesto, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure abrasive, Abrasive wear, Desgaste abrasivo, Abrasivverschleiss, abrasive wear behavior, cBN-NiCrAl, cold spray, mechanical properties, microstructure, and nanocomposite

20 vol.% cubic boron nitride (cBN) dispersoid reinforced NiCrAl matrix nanocomposite coating was prepared by cold spray using mechanically alloyed nanostructured composite powders. The as-sprayed nanocomposite coating was annealed at a temperature of 750 °C to enhance the inter-particle bonding. Microstructure of spray powders and coatings was characterized. Vickers microhardness of the coatings was measured. Two-body abrasive wear behavior of the coatings was examined on a pin-on-disk test. It was found that, in mechanically alloyed composite powders, nano-sized and submicro-sized cBN particles are uniformly distributed in nanocrystalline NiCrAl matrix. Dense coating was deposited by cold spray at a gas temperature of 650 °C with the same phases and grain size as those of the starting powder. Vickers hardness test yielded a hardness of 1063 HV for the as-sprayed 20 vol.% cBN-NiCrAl coating. After annealed at 750 °C for 5 h, unbonded inter-particle boundaries were partially healed and evident grain growth of nanocrystalline NiCrAl was avoided. Wear resistance of the as-sprayed 20 vol.% cBN-NiCrAl nanocomposite coating was comparable to the HVOF-sprayed WC-12Co coating. Annealing of the nanocomposite coating resulted in the improvement of wear resistance by a factor of ∼33% owing to the enhanced inter-particle bonding. Main material removal mechanisms during the abrasive wear are also discussed.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Microstructure, Microestructura, Mikrogefuege, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Biodegradable Mg, Coating, Mechanical behaviour, Scaffold, and Tissue engineering

In recent years, attention has been focused on the magnesium (Mg) as a promising material in biodegradable metallic scaffolds for bone tissue engineering. Since an orthopedic scaffold is supposed to repair and regenerate fractured bones, its mechanical integrity is vital throughout the healing process. In this study, a biocompatible polymeric layer made of polycaprolactone (PCL) in different concentrations of 3% w/v and 6% w/v was coated on the surface of Mg scaffolds. The structural characteristics and mechanical behaviour of the Mg scaffolds during the immersion in physiological saline solution (PSS) were investigated. According to our results, the PCL coating hindered the diminution of mechanical stability of scaffolds to provide adequate support for bone healing. Specifically, scaffold coated with 3% w/v and 6% w/v PCL demonstrated 24 and 100% improvement in the elastic modulus and 41 and 83% enhancement in compressive strength respectively, after 24 h immersion in PSS, compare to the uncoated scaffold. Thus, PCL coating of Mg scaffolds may be a promising approach in the development of mechanically stable bone scaffolds.

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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Poudres métalliques, Metal powders, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Alliage mécanique, Mechanical alloying, Aleación mecánico, Mechanisches Legieren, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Projection HVOF, HVOF spraying, Proyeccion HVOF, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement composite, Composite coating, Revestimiento compuesto, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, HVOF, cold spray, mechanical alloying, mechanical properties, metal matrix composite, and nickel alloys

The purpose of this study is to manufacture metal matrix composite coatings by thermal spraying. In order to improve coating's mechanical properties, it is necessary to increase homogeneity. To meet this objective, the chosen approach was to optimize the powder morphology by mechanical alloying. Indeed, the mechanical alloying method (ball milling) was implemented to synthesize NiCr-Cr3C2 and NiCrBSi-WC composite powders by using cold spraying and high-velocity oxygen fuel process, respectively. After optimizing the process parameters on powder grain size, the composite coatings were compared with standard coatings manufactured from mixed powders. SEM observations, hardness measurements, and XRD analyses were the first technologies implemented to characterize the metal matrix composite coatings. Different characteristics were then observed. When mechanical alloying process is employed to synthesize composite powders strengthened by particle dispersion, the powders tend to fracture into small segments, especially when high content of hard particles is added. Powder microstructures were then refined, which induced thinner coating morphologies and reduced porosity rate. Once an improved microstructure is obtained, manufacturing of coating using milled powders was found suitable in comparison with coatings manufactured only with mixed powders.

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, 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, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Laser, Láser, Nanoparticule, Nanoparticle, Nanopartícula, Projection HVOF, HVOF spraying, Proyeccion HVOF, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Résistance usure, Wear resistance, Resistencia al desgaste, Verschleissfestigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, B4C nanoparticles, H188 alloy, HVOF coating, laser treatment, residual stress, and wear resistance

Laser treatment under nitrogen assisting gas environment of cobalt-nickel-chromium-tungsten-based superalloy and high-velocity oxygen-fuel thermal spray coating of nickel-chromium-based superalloy on carbon steel was carried out to improve mechanical and tribological properties. Superalloy surface was preprepared to include B4C particles at the surface prior to the laser treatment process. Material and morphological changes in the laser-treated samples were examined using scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction (XRD) analysis. Residual stresses present at the surface region of the laser-treated layer were determined from the XRD data. The microhardness of the laser-treated surface was measured by indentation tests. Fracture toughness of the coating surfaces before and after laser treatment were also measured using overload indentation tests. Macrowear and macrofriction characterization were carried out using pin-on-disk tests.

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 ressort, Spring steel, Acero resorte, Federstahl, Diagramme SN, SN diagram, Diagrama SN, Woehler Kurve, Essai fatigue, Fatigue test, Ensayo fatiga, Dauerschwingversuch, Fatigue, Fatiga, Ermuedung, Grenaillage, Shot peening, Granalla, Kugelstrahlen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Ressort, Spring, Resorte, Feder, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Helical compression springs, S-N curves, Spring steels, and Very high cycle fatigue test

Long-term fatigue tests on shot peened helical compression springs were conducted by means of a special spring fatigue testing machine at 40 Hz. Test springs were made of three different spring materials ― oil hardened and tempered SiCr- and SiCrV-alloyed valve spring steel and stainless steel. With a special test strategy in a test run, up to 500 springs with a wire diameter of d = 3.0 mm or 900 springs with d = 1.6 mm were tested simultaneously at different stress levels. Based on fatigue investigations of springs with d = 3.0 mm up to a number of cycles N = 109 an analysis was done after the test was continued to N = 1.5 × 109 and their results were compared. The influence of different shot peening conditions were investigated in springs with d = 1.6 mm. Fractured test springs were examined under optical microscope, scanning electron microscope (SEM) and by means of metallographic microsections in order to analyse the fracture behaviour and the failure mechanisms. The paper includes a comparison of the results of the different spring sizes, materials, number of cycles and shot peening conditions and outlines further investigations in the VHCF-region.

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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Métaux renforcés par dispersion, Dispersion hardening metals, Traitements de surface, Surface treatment, 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, Techniques de l'ingénieur appliqués à la métallurgie. Applications. Divers, Engineering techniques in metallurgy. Applications. Other aspects, Applications, Industrie automobile, Automotive engineering, Propriété mécanique, Mechanical properties, Propiedad mecánica, Alliage mécanique, Mechanical alloying, Aleación mecánico, Mechanisches Legieren, Application, Aplicación, Anwendung, Carbure de silicium, Silicon carbide, Silicio carburo, Siliciumcarbid, Céramique, Ceramic materials, Cerámica, Keramik, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Fabrication, Manufacturing, Fabricación, Fertigung, Industrie automobile, Automobile industry, Industria automóvil, Autoindustrie, Industrie aéronautique, Aeronautic industry, Industria aeronáutica, Luftfahrtindustrie, Industrie aérospatiale, Aerospace industry, Industria aeroespacial, Raumfahrtindustrie, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Métal renforcé dispersion, Dispersion strengthened metal, Metal reforzado dispersión, Dispersionsgehaertetes Metall, Nanostructure, Nanoestructura, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Revêtement composite, Composite coating, Revestimiento compuesto, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, aerospace applications, aluminum alloys, automotive applications, ceramic matrix composite feedstock, mechanical alloying feedstock, nanocomposite feedstock, and wear-resistant coatings applications

6061Al powder with 15 wt.% SiC particulate (SiCp) reinforcement was mechanically alloyed (MA) in a high-energy attrition mill. The MA powder was then plasma sprayed onto weathering steel (Cor-Ten A242) substrate using an atmospheric plasma spray process. Results of particle size analysis and scanning electron microscopy show that the addition of SiC particles as the reinforcement influences on the matrix grain size and morphology. XRD studies revealed embedment of SiCp in the MA-processed composite powder, and nanocrystals in the MA powder and the coating. Microstructural studies showed a uniform distribution of reinforced SiC particles in the coating. The porosity level in the coating was as low as 2% while the coating hardness was increased to 232VHN. The adhesion strength of the coatings was high and this was attributed to higher degree of diffusion at the interface. The wear rate in the coatings was evaluated using a pin-on-disk type tribometer and found to decrease by 50% compared to the 6061Al matrix coating. The wear mechanism in the coating was delamination and oxidative type.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Rupture, Fractures, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Erosion, Erosión, Modélisation, Modeling, Modelización, Méthode élément fini, Finite element method, Método elemento finito, Finite Element Methode, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rupture, Ruptura, Bruch, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse, Velocity, Velocidad, Cold spray, Euler, FEA, Multimaterial, and Multiparticle

Finite element analysis on the high velocity impact behaviour in cold spraying is conducted using the Euler method. The simulation results demonstrate that the Euler method is capable of realising the reliable simulation on some complicated impact processes. The comparative deformation ratio (CDR) is proposed, which is defined as the ratio of dimensionless crater depth to compressional ratio, to evaluate the comparative deformation degree between the particle and substrate. Proper CDR and sufficiently large compressional ratio can ensure the well bonding between the particle and substrate. Furthermore, for the multiparticle impact process, it is found that, after the deposition of the first layer coating, the subsequent impact process can be considered as particles impacting on the same material no matter what substrate is coated. When the velocity is increased to a hypervelocity (erosion velocity), extreme erosion occurs in the substrate or the formed coatings, resulting in the poor performance of the coating.

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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Métaux et alliages frittés. Cermets, Sintered metals and alloys. Pseudo alloys. Cermets, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Décharge étincelle, Spark discharge, Descarga chispa, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Frittage, Sintering, Sinterización, Sintern, Microstructure, Microestructura, Mikrogefuege, Métallurgie poudre, Powder metallurgy, Metalurgia polvo, Pulvermetallurgie, Plasma, Projection plasma, Plasma spraying, Proyección plasma, Plasmaspritzen, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, cold spray, copper, heat treatment, mechanical property, microstructure, and spark-plasma sintering

Cold-spray is well known as an effective coating technique to make thick metallic coatings. However, cold-sprayed metallic coatings usually have low tensile strengths due to low adhesion strength between particles, and low ductility due to low adhesion strength between particles and work hardening. Spark-plasma sintering (SPS) is a pressure-sintering technique that employs a large pulsed direct current. Compared to annealing heat treatment (AHT), SPS is expected to effectively improve the adhesion strength between particles in cold-sprayed metallic coatings. In order to investigate the effects of SPS, cold-sprayed Cu coatings were treated by both SPS and AHT under a wide range of temperatures. The microstructures and mechanical properties of the treated specimens were investigated primarily by scanning electron microscopy, electron backscatter diffraction analysis, hardness tests, and tensile tests. Despite comparable values for porosity, crystal grain size, plastic strain distribution, hardness, and yield stress, the tensile strength and ductility of the specimen treated by SPS at 400 °C (SPS400) were significantly higher than those of the specimen treated by AHT at 450 °C. Based on these results, it was determined that SPS treatment is more effective in improving the adhesion strength between the particles in cold-sprayed Cu coatings than AHT.

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, Métallurgie des poudres. Matériaux composites, Powder metallurgy. Composite materials, Métaux renforcés par dispersion, Dispersion hardening metals, Traitements de surface, Surface treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Alliage base magnésium, Magnesium base alloys, Carbure de silicium, Silicon carbide, Silicio carburo, Siliciumcarbid, Dimension particule, Particle size, Dimensión partícula, Teilchengroesse, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Fraction volumique, Volume fraction, Fracción volumétrica, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Métal renforcé dispersion, Dispersion strengthened metal, Metal reforzado dispersión, Dispersionsgehaertetes Metall, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement composite, Composite coating, Revestimiento compuesto, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, bonding strength, cold spraying, composite coating, and magnesium alloy

AZ91D/SiCp composite coatings were fabricated on AZ31 magnesium alloy substrates using cold spraying. The effects of SiC volume fraction and particle size on the deposition behavior, microhardness, and bonding strength of coatings were studied. The mean sizes of SiC particles tested were 4, 14, and 27 μm. The results show that fine SiC particles (d0.5 = 4 μm) are difficult to be deposited due to the bow shock effect. The volume fraction of SiC particles in composite coatings increases with the increasing SiC particle size. The microhardness and bonding strength of composite coatings also show increases compared with AZ91D coatings. The volume fractions of SiC particles in the original powder were set at 15, 30, 45, and 60 vol.%. The corresponding contents in composite coatings are increased to 19, 27, 37, and 51 vol.%, respectively. The microhardness of composite coatings also increases as the volume fraction of SiC particles increases.

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, 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, Addition lanthanide, Rare-earth metal addition, Adición lantánido, Seltenerdmetallzusatz, Carbure de tungstène, Tungsten carbide, Wolframio carburo, Wolframcarbid, Carbure fritté, Cemented carbides, Carburo sinterizado, Hartmetall, Cobalt, Cobalto, Dépôt projection, Spray coating, Depósito proyección, Spritzbeschichten, Lanthanide, Lantánido, Microstructure, Microestructura, Mikrogefuege, Nanostructure, Nanoestructura, Projection HVOF, HVOF spraying, Proyeccion HVOF, Projection à chaud, Hot spraying, Proyección en caliente, Spritzen, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, decarburization, mechanical properties, nanostructure, and rare earth

Rare earth has been widely used in materials manufacturing to improve hardness and toughness. In this paper, conventional, nanostructured, and rare earth CeO2-doped WC-12Co powders were sprayed by using HVOF spraying technology. Microstructure, hardness, elastic modulus, and fracture toughness of the three coatings were investigated. The results showed that nanostructured WC-12Co coatings possessed the densest microstructure and excellent combination of strength and toughness. The WC particles with the size ranging from 50 to 500 nm distributed uniformly in the nanostructured WC-12Co coating. The average free path of Co matrix in rare earth-doped WC-12Co coating was shorter than that of conventional WC-12Co coating. XRD results showed no obvious decarburization in all three coatings. The addition of rare earth could improve the mechanical properties of the coating compared with that without rare earth. The hardness value of nanostructured WC-12Co coating (12.2 GPa) was similar to that of rare earth-doped WC-12Co coating (12.2 GPa), which was 15.1% higher than that of conventional WC-12Co coating. The elastic modulus and fracture toughness of nanostructured WC-12Co coating were the highest, and that of conventional WC-12Co coating was the lowest.

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, Fatigue, Fatiga, Ermuedung, Fonte, Cast iron, Fundición, Gusseisen, Grenaillage, Shot peening, Granalla, Kugelstrahlen, Microcristallisation, Microcrystallization, Microcristalización, Microstructure, Microestructura, Mikrogefuege, Nanocristal, Nanocrystal, Propriété mécanique, Mechanical properties, Propiedad mecánica, Résistance fatigue, Fatigue strength, Resistencia fatiga, Dauerfestigkeit, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Nodular cast iron, Severe shot peening, and Surface nanocrystallization

Effect of nanocrystalline surface obtained by severe plastic deformation on fatigue strength of nodular cast iron has been studied in the paper. Surface nanocrystallization has been applied by means of standard air blast shot peening equipment with particularly severe parameters compared to the usual ones used for similar classes of material. Microscopy observation, microhardness, surface roughness and X-ray diffraction measurements were carried out to characterize the treated surface of differently shot peened specimens. Rotating bending fatigue tests were performed to investigate the effects of process parameters on fatigue behaviour. The results indicate a sensible fatigue strength improvement obtained through application of severe shot peening with respect to conventional shot peening, notwithstanding the specimen's very high surface roughness due to high energy impacts. The obtained results are critically discussed.

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, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Déformation, Deformation, Deformación, Verformung, Propriété mécanique, Mechanical properties, Propiedad mecánica, Préchauffage, Preheating, Precalentamiento, Vorwaermen, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Cold spraying, and Deformation behaviour

The present paper used an Eulerian model to study effects of the substrate material and the substrate temperature on the particle deformation behaviour in cold spraying dissimilar particle/substrate combinations. Results show that the deformation pattern of the particle presents a spreading and penetration way for soft/hard and hard/soft particle/substrate material combinations respectively. In addition, preheating the substrate can achieve a coordinated deformation pattern for the soft/hard particle/substrate material combination and a maximum steady PEEQ ranging in 3·2-3·5 in the present study.

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, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, 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, Etat surface, Surface conditions, Estado superficie, Oberflaechenzustand, Alliage base aluminium, Aluminium base alloys, Couche mince, Thin film, Capa fina, Duennschicht, Dureté, Hardness, Dureza, Haerte, Epaisseur, Thickness, Espesor, Dicke, Magnésium alliage, Magnesium alloy, Magnesio aleación, Magnesiumlegierung, Propriété mécanique, Mechanical properties, Propiedad mecánica, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, and Amorphous

This work explored the effect of deposition pressure on the properties of the ternary AI―Mg―B thin films deposited on Si substrate at high deposition temperature (600°C) by magnetron sputtering system with one pure boron target and one Al/Mg co-target. The influences of the deposition pressure on the elemental contents, deposition rate, surface roughness, structure and mechanical properties were investigated by Electron microprobe analysis (EPMA), 3D surface profiler, X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and nanoindentation experiments respectively. Experimental results indicated that the amorphous thin films deposited at 0·5 Pa had a smooth surface and displayed the maximum hardness and Young's modulus of 35 and 322 GPa respectively. From the results of this work, high quality Al―Mg―B hard thin films can be obtained by magnetron sputtering under an optimum deposition pressure of 0·5 Pa.