Antonio Forn | Universitat Politecnica de Catalunya (original) (raw)

Papers by Antonio Forn

Revista de Metalurgia, 2005

Resumen En el presente trabajo se estudia el comportamiento frente al desgaste de la aleación de ... more Resumen En el presente trabajo se estudia el comportamiento frente al desgaste de la aleación de aluminio 6061 reforzada con partículas de AI2O3, con un tamaño medio de partícula de 13,6 jLlm. El material, obtenido mediante proceso "Duralcan", ha sido extruido en caliente y, posteriormente, sometido a un tratamiento térmico T6. Utilizando un equipo de Pin-on-disCj con pin esférico de WC-6 % Co, se han evaluado la resistencia al desgaste y el coeficiente de fricción para diferentes condiciones de carga, a temperatura ambiente y en ausencia de lubricación. También se ha estudiado la evolución del desgaste producido a distinto número de ciclos. El análisis de la huella de desgaste y de la sección perpendicular a la superficie desgastada, mediante microscopía electrónica de barrido (SEM), ha permitido conocer el mecanismo asociado al desgaste en las diferentes condiciones ensayadas, encontrándose, en todos los casos, desgaste por abrasión. Palabras clave Materiales compuestos. Aluminio. Desgaste. Fricción. Wear behaviour of aluminium metal matrix composites reinforced with ceramic particles

Surface Engineering, 2006

ABSTRACT A MoS2/titanium coating has been developed in order to improve the mechanical and tribol... more ABSTRACT A MoS2/titanium coating has been developed in order to improve the mechanical and tribological characteristics of pure MoS2. These coatings were produced by physical vapour deposition closed field unbalanced magnetron sputtering on stainless steel substrates. In this work, a comparative study of the mechanical and tribological characteristics of both coatings is carried out. The coating hardness and Young's modulus have been determined by means of an ultramicroindenter. The friction and wear tests have been carried out with a pin on disc tribometer in several conditions of load and humidity. The MoS2/titanium coating exhibited a better mechanical and tribological behaviour in comparison with pure MoS2 coating on increasing the percentage of humidity.

International Journal of Refractory Metals and Hard Materials, 2005

The present study describes and compares the mechanical and tribological properties of CrN coatin... more The present study describes and compares the mechanical and tribological properties of CrN coatings deposited by PVD/CAPD (Cathodic Arc Plasma Deposition) on three different substrates: steel, aluminium alloy and reinforced aluminium alloy. The coatingsubstrate interfaces were analysed by scanning electron microscopy (SEM). The ultra-microindentation technique was applied to measure coating hardness. Experiments using a tribometer (pin on disc configuration) under lubricated conditions have been performed in order to evaluate the friction and wear properties of the different systems. The measured coating hardness depends on the indentation depth reached in the ultra-microindentation tests. In this study the coating-substrate system has been characterized, analyzing the hardness variation from the coating to the substrate by different indentation depths, and modelling the experimental curve with a universally approved mathematical model. The CrN-steel system exhibits the best performance, in which the system hardness is close to the CrN coating hardness. The CrN-AMC system performs better than CrN-aluminium but worse than CrN-steel system.

$Research paper thumbnail of A6061/(Al2O3)p fracture behaviour$

Boletín de la Sociedad Española de Cerámica y Vidrio, 2004

Se estudian las propiedades de las aleaciones de aluminio 6061/(20%Al 2 O 3) p obtenidas por cola... more Se estudian las propiedades de las aleaciones de aluminio 6061/(20%Al 2 O 3) p obtenidas por colada y conformadas posteriormente por extrusión y forja. Estos materiales son sometidos a tratamientos térmicos de envejecimiento (T6) para estudiar su efecto en las propiedades mecánicas. En este trabajo se comparan las características de la matriz con las del material reforzado en las distintas etapas de producción utilizando técnicas de microscopía óptica y electrónica, EDS y ensayos de tracción, fatiga y ultramicroindentación. Los ensayos mecánicos indican que el material compuesto extruido presenta valores de resistencia mecánica más bajos que la aleación 6061 tratada en las mismas condiciones y ello se relaciona con la presencia de espinela en la interfase alúmina-matriz. Se establecen los mecanismos de fractura por tensiones estáticas y dinámicas en los distintos casos, estudiando las posibles interacciones matriz-refuerzo y su influencia en el comportamiento mecánico de la aleación.

Powder Technology, 2004

One of the leading production method to create nanostructured materials for thermal spray applica... more One of the leading production method to create nanostructured materials for thermal spray applications is mechanical alloying. The mechanical milling process is a high-energy ball milling technique that produces materials at nanometric level. This paper reviews the main techniques to obtain nanomaterials and describes the synthesis of the nanocrystalline NiCrAlY powder by mechanical cryomilling. The microstructure and morphology of the nanostructured NiCrAlY powders were characterized by XRD, SEM and TEM.

An A356 aluminium alloy manufactured in semisolid state by Sub Liquidus Casting technology (SLC) ... more An A356 aluminium alloy manufactured in semisolid state by Sub Liquidus Casting technology (SLC) has been investigated. The Temperature ant times effect in age hardening (T5 and T6 treatments) has been analyzed, to optimise mechanical properties. The material was characterized by optical and electronic microscopy, hardness test and tensile test. The fracture mechanisms have been determinated by fractographic analysis. () Centro de Diseno de Aleaciones Ligeras y Tratamientos de Superficie (CDAL) Departamento de Ciencia de los Materiales e Ingenieria Metalurgica UPC Avda. Victor Balaguer s/n. 08800 Vilanova i la Geltru (Barcelona)

En este trabajo se ha estudiado el efecto del tratamiento de anodizado en las propiedades superfi... more En este trabajo se ha estudiado el efecto del tratamiento de anodizado en las propiedades superficiales de componentes AlSi conformados en estado semisolido. Los componentes fueron conformados mediante una maquina de inyeccion a alta presion y una estacion Idra de Semi Solid Rheocasting (SSR), empleando una aleacion de segunda fusion EN AC- 46500. Las muestras se trataron termicamente con el objetivo de modificar la forma y la distribucion del silicio eutectico, y posteriormente fueron granalladas para obtener distintas rugosidades. Finalmente, los componentes fueron anodizados con el proposito de mejorar sus propiedades tribologicas y la resistencia a la corrosion. Para ello, se llevaron a cabo antes y despues del proceso de anodizado, ensayos de desgaste con un tribometro Pin on disc y ensayos acelerados de corrosion en niebla salino-acetica. Los componentes anodizados muestran una mejora significativa de la resistencia a la corrosion y resistencia al desgaste en las condiciones e...

This work demonstrates the possibility to apply T5 and T6 heat treatments to L-2630 aluminium com... more This work demonstrates the possibility to apply T5 and T6 heat treatments to L-2630 aluminium components conformed by Semi-Solid Rheocasting (SSR). The study of temperature and time effect in annealing, tempering and artificial aging conditions, has permitted to optimize the component mechanical properties. The experimentation has been accomplished by means of hardness Brinell tests, tensile tests, optic and electronic microscopy, and fractographic analysis. The mechanical properties obtained in SSR components, reach analogous values to the ones obtained by die cast components and submitted to the same heat treatments. () Centro de Diseno de Aleaciones Ligeras y Tratamientos de Superficies, Universitat Politecnica de Catalunya, Espana manel.campillo@upc.edu, maite.baile@upc.edu, enric.martin@upc.edu, antonio.forn@upc.edu.

AIP Conference Proceedings, 2007

A comparative study was performed on the corrosion behavior of a component of A380 aluminium allo... more A comparative study was performed on the corrosion behavior of a component of A380 aluminium alloy obtained by Semi-Solid Rheocasting (SSR). The effect of heat treatments T5 and T6 on corrosion resistance was compared with components without heat treatment by SSR processes. Corrosion studies were performed using an acetic acid salt spray test, impedance measurements and polarization curves using a

International Journal of Material Forming, 2008

Boletín de la Sociedad Española de Cerámica y Vidrio, 2005

Se realiza un estudio comparativo del comportamiento frente a la corrosión de la aleación de alum... more Se realiza un estudio comparativo del comportamiento frente a la corrosión de la aleación de aluminio 2124 reforzada con partículas de carburo de silicio, obtenida por pulvimetalurgia y con tratamientos térmicos T4 y T6. Los resultados experimentales muestran que el tratamiento térmico T6 induce la formación de numerosos intermetálicos que reducen la resistencia a la corrosión. Las partículas de carburo de silicio no tienen un comportamiento catódico con respecto a la matriz de aluminio, sin embargo, disminuyen la resistencia a la corrosión, ya que generan zonas más activas en la interfase matriz/ refuerzo, debido a la acumulación de dislocaciones, tensiones residuales y a la precipitación de intermetálicos.

The study compares the mechanical and fracture behaviour of several AlSiMg automotive components ... more The study compares the mechanical and fracture behaviour of several AlSiMg automotive components in as-casted state and after T5 and T6 heat treatments. The components were manufactured using different semi- solid technologies: Thixocasting (TC), New Rheocasting (NRC) and Sub Liquidus Casting (SLC). The results layout the possibilities of these technologies as an alternative to cast-ironed components.

International Journal of Material Forming, 2010

In this work the affects of laser characteristics on microstructure and microhardness of high vel... more In this work the affects of laser characteristics on microstructure and microhardness of high velocity oxygen fuel sprayed (HVOF) WC-CoCr coatings were investigated. The coating was deposited with a Sulzer Metco WokaJet™-400 kerosene fuel and the laser surface treatments were applied using CO 2 laser with 10.6 μm wavelength. Large variations in surface properties were produced from variation in the laser processing parameters. In total, four levels of peak power (100, 200, 300 and 350 W), four levels of spot diameter (0.2, 0.4, 0.6 and 1 mm) and three levels of pulse repetition frequency (PRF) were investigated. An initial set of tests were followed by a more detailed 3 3 factorial design of experiments. Pulse repetition frequency and duty cycle were set in order to maintain the same overlap in the x and y directions for the raster scanned sample spot impact dimensions. Overlaps of 30% were used in the initial tests and 10% in the more detailed trials. The results have shown that care must be taken to keep the irradiance at a relatively low level compared to uncoated surfaces. High irradiance can in this case result in rough and porous surfaces. Lower levels of irradiance are shown to provide more uniform microstructures, reduced porosity and increased microhardness.

The aim of this work is to analyze and compare two anodized components: a cast A356 T6 alloy prod... more The aim of this work is to analyze and compare two anodized components: a cast A356 T6 alloy produced by an SLC technique and an extruded A6061 T6 alloy. The corrosion mechanisms of anodized specimens are studied by electrochemical test, salt spray test and optical and scanning electron microscopy. The mechanical properties and corrosion resistance of the two alloys are compared and the viability of the SLC components as an alternative to extruded alloys for marine applications is discussed.

Semisolid AlSiMg casting alloys are attractive alternatives for automotive and aeronautical appli... more Semisolid AlSiMg casting alloys are attractive alternatives for automotive and aeronautical applications. In this work the effects of heat treatments on hardness and tribological properties of A356 aluminium alloy obtained by Sub-Liquidus Casting (SLC) were studied. The optimum heat treatment conditions, in which the material presents the maximum hardening and wear resistance values, were determined. Heat treatment conditions investigated included: A356 SLC as cast, T5 and T6. Furthermore, AC-46500 and A6061/T6 were analyzed for comparison. The tribological properties of the samples were investigated by pin-on-disc tests at 5 N and 0.05 and 0.1 m•s-1 in dry conditions. The samples were studied by SEM-EDX techniques in order to determine the wear mechanisms and the determination of the products produced during the tests. The maximum hardness and the lowest dry wear rate were obtained through T6 thermal treatment condition.

This work is a contribution to improve understanding about the behaviour of components produced b... more This work is a contribution to improve understanding about the behaviour of components produced by semi-solid processes. The present study shows the effect of different conformation parameters on automotive cranking cover production obtained by Semi-Solid Rheocasting Process (SSR®). The components were produced using EN AC-46500 alloy, by an industrial plant with a 700 Ton HPDC machine and an IDRA SSR Station. The process parameters studied were slurry temperature, agitation time, speed injection and lubrication system. The characterization was carried out by microstructural analysis, X-rays and mechanical tests. The components show good mechanical properties, similar to those obtained by die cast. The process was simulated using the PROCAST program.