Browsing by Author "Goñi, J."
Now showing 1 - 20 of 20
Results Per Page
Sort Options
Item L'Al-TiB 2, un matériau pour les applications du secteur des transports nécessitant résistances aux températures élevées et à l'usure(2002-12) Goñi, J.; Egizabal, P.; Coleto, J.; Poutier, M. A.; Guridi, J. R.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoThe transport industry is continuously seeking new light materials to comply with the low fuel consumption policies and enhanced technical requirements. The use of Metal Matrix Composites (MMCs) is seen as a feasible alternative to substitute several grey cast iron steel and non reinforced aluminium alloys components as they present outstanding specific properties, high wear resistance as well as low Coefficient of Thermal Expansion (CTE). The results obtained during a research project that studied the actual possibilities, processing optimisation and mechanical properties of an aluminium matrix composite reinforced with in-situ produced TiB 2 ceramic particles are presented. Railway and automotive components were produced by Gravity Casting, High Pressure Die Casting (HPDC) and a variant of the Sand Casting process called "Multipouring" and the melt behaviour and obtained mechanical properties were analysed and evaluated. The material presented a remarkable improvement of properties when compared with the corresponding non-reinforced alloys. Furthermore, the presence of the TiB 2 particles conferred a thixotropic nature to the melt whose positive effects during the filling step could also be noticed during the production of prototypes.Item Characterisation of orthorhombic (Ti25Al25Nb)/SiC intermetallic composites for advanced space applications(2003) Coleto, J.; Goñi, J.; Egizabal, P.; García de Cortazar, M.; Lilly, G.; Sainz, X.; Pambaguian, L.; Mercado; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; CIRMETALIntermetallic Matrix Composites (IMC) represent a relatively new area in the field of advanced materials. The combination of an intermetallic matrix and continuous reinforcements provides exceptional levels of room and elevated temperature strength, stiffness as well as low density. In particular, titanium aluminide composites reinforced with continuous fibres have recently received considerable attention due to their potential to replace titanium and the higher density nickel based superalloys for some applications. Aerospace structures and components in both jet engines and hypersonic vehicles -in which specific strength and stiffness, environmental conditions and working temperatures are paramount- could benefit from the development of these IMCS. Hot-skin, structural components and structures within the propulsion area of reusable vehicles are some of the potential components already identified for these advanced IMCS. Taking into account this scenario, the present work has developed and optimised the diffusion bonding technique for manufacturing orthorhombic titanium aluminide matrix composites, with a nominal composition of Ti-25Al-25Nb (at%) reinforced with continuous SiC fibres. The composite was manufactured comprising 4 unidirectional plies of SiC monofilaments (SM1140+ type from DRA) by uniaxial hot pressing through the foil/fibre/foil technique. Fibre/matrix interface and composite microstructure were examined by means of optical and electronic microscopies showing much lower reactivity than other titanium aluminide and titanium alloy based composites. The analytical electronic microscopy was mainly used for chemical analysis at the matrix/reinforcement interface in order to identify possible reaction compounds formed as well as the chemistry of the phases surrounding them. Three point bending tests were also performed with samples obtained from the panels manufactured.Item A comparative study on the performance of ventilated brake discs manufactured in different advanced materials(2001) Goñi, J.; Mitxelena, I.; Rubio, A.; Coleto, J.; Terrón, A.; García, A.; Sánchez, J.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoTwo different aluminium alloy materials have been used to produce ventilated brake discs, on one hand, AS17G0.6 hypereutectic alloy and on the other hand, AS7G0.6 reinforced with 20% in wt. of SiC particles. The casting production technique used has been Low Pressure Casting (LPC) and some of the brake discs have been heat treated using a T6 treatment. Once the ventilated brake discs were produced and machined, they were tested in a dynamometer in order to compare the performance under service conditions of the aluminum alloy and grey cast iron (GCI) discs currently used in the market.Item Development of aluminium alloys for the thixoforming process(2004) Azpilgain, Z.; Hurtado, I.; Basterrechea, G.; Gandarias, E.; Goñi, J.; Eguizabal, P.; Lakehal, M.; Sarriés, I.; Landa, I.; Wielanek, L.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & InnovationThe aluminium alloys A356 and A357 remain, up to the present, the most used alloys for the semisolid processing of components. Nevertheless, several authors have pointed out the gain in properties or economics that other alloy families could provide. In the present work two complementary alloy families are considered. From an economical point of view, modifications necessary to increase the properties of second fusion alloys are carried out. From the point of view of the potential of their properties, wrought alloys are modified and tested. A New Rheocasting pilot unit is used for obtaining the alloys with thixotropic characteristics. Previous work on the identification of the microstructural variables which determine the properties of the components allow to reduce those variables to the variation of the solid-liquid fraction as a function of the temperature, the particle size distribution, the particle aspect ratio and the esqueletonization. The composition variations in both alloy families are thus considered under the point of view of the control and optimisation of those parameters. In addition to the metallographic studies, thermodynamic calculations and calorimetry experiments have been performed to determine the optimum process window of the new alloys. A "direct squeeze casting method" with a preheated die has been used to obtain samples for the determination of mechanical properties.Item Development of automotive components locally reinforced with metal matrix composite inserts(2000-09) Goñi, J.; Fernández, R.; Mitxelena, I.; Coleto, J.; Guridi, J. R.; Centros PRE-FUSION TECNALIA - (FORMER); Biomateriales; Tecnalia Research & Innovation; MercadoMetal Matrix Composites (MMC) based on aluminum alloys are currently one of the most interesting alternatives, due to their high performance level, for different commercial applications. The main objective of this work is the development of locally reinforced automotive components where the MMC insert is located in the areas where the level of performance needed is higher than that offered by conventional materials. In this way, the production of competitive products with a high performance level will be possible in which only concrete areas, mainly those in need of a high wear resistance, of the part are reinforced. Two conventional foundry technologies have been previously selected (High Pressure Die Casting and Low Pressure Casting), that are known to be largely competitive. Likewise, two different kinds of MMC inserts have been initially considered, inserts made of AllSiCp commercial MMCs and inserts mode of porous preforms, for the fabrication of two different automotive components: a clutch disc and a ventilated brake disc.Item Development of low cost metal matrix composites for commercial applications(2000) Goñi, J.; Mitxelena, I.; Coleto, J.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoMetal matrix composites are considered as a possible material to replace the materials actually used in some automotive and railway industrial components. Two different ways of taking advantage of the properties of MMCs at low cost are presented: locally reinforced aluminium components and new castable aluminium MMCs developed by the London & Scandinavian Metallurgy Co. (LSM).Item Development of new low cost discontinuously reinforced titanium composites for commercial applications(Trans Tech Publications Ltd, 2007) De Cortázar, M. Garcia; Goñi, J.; Coleto, J.; Agote, I.; Egizabal, P.; Le Petitcorps, Y.; CIRMETAL; Centros PRE-FUSION TECNALIA - (FORMER); Mercado; EXTREMAT; Tecnalia Research & InnovationA new cost effective process to produce discontinuously reinforced (TiB) TMCs has been developed. The article presents general features of the composites, microstructural characteristics and mechanical properties. The production and characterization of two potential commercial applications are also discussed.Item Fabrication de mousses métalliques à cellules ouvertes ou fermées, par les voies de la fonderie, et applications de ces mousses(2004-10) Coleto, J.; Goñi, J.; Maudes, J.; Leizaola, I.; Mercado; Centros PRE-FUSION TECNALIA - (FORMER); PRINTEX; EXTREMATDuring the last two decades, research and development in cellular materials and metallic foams has been quite intensive, leading to a great number of technical papers, proceedings of conferences and scientific books, as wet as a number or European companies offering commercial products. Among the different manufacturing technologies developed for the production of open and closed cell metal foams, the present paper will give an overview of those based on foundry routes, as Well as a more detailed information of the activities performed at INASMET for the production of non- ferrous metal foams by melt processes along the last years. Closed cell metal foams are produced by foaming foamable precursors into moulds, while open pore metal foams are produced through investment casting techniques. The use of close cell metal foams produced in moulds for automotive, aeronautic and space applications for impact energy absorption or noise attenuation, and applications of open pore metallic foams as heat exchangers in industrial devices or cooling in power electronics will be reviewed.Item Fracture analysis of the transition zone between unreinforced alloy and composite(1993-10) Goñi, J.; Muñoz, A.; Viviente, J. L.; Liceaga, J. F.; Centros PRE-FUSION TECNALIA - (FORMER); TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe transition zone between unreinforced alloy and composite is an important problem for selectively reinforced metal-matrix composites manufactured by the squeeze casting technique, mainly because of the weakness of this zone. Developing an understanding of transition zone behaviour is therefore essential. The main purpose of this research was to evaluate the influence of ageing time on the fracture behaviour of such a zone for Saffil (γ-alumina) A356 aluminium alloy composites. Tensile tests were carried out and the fracture surfaces were analysed to evaluate the fracture behaviour. Analysis of microstructure and fracture surfaces was performed using optical and scanning electron microscopies.Item Heat treatments effect on A357 components produced by SSM(Trans Tech Publications Ltd, 2006) Forn, A.; Baile, M. T.; Martín, E.; Goñi, J.; Sarriés, I.; Centros PRE-FUSION TECNALIA - (FORMER)The present work studies the effect the solution heat treatment, during artificial ageing and re-aging, has on the mechanical properties of an A357 aluminium alloy component formed by New Rheocasting. The effect that the evolution of silicon, during the solution treatment at various times, has on the mechanical properties was also examined. The mechanical properties were evaluated performing tensile tests, fractographical analysis and hardness tests. The microstructural characterization was made using optical and electronic microscopy.Item Heat treatments effect on A357 components produced by SSM(2006) Forn, A.; Baile, M. T.; Martín, E.; Goñi, J.; Sarriés, I.; Centros PRE-FUSION TECNALIA - (FORMER)The present work studies the effect the solution heat treatment, during artificial ageing and re-aging, has on the mechanical properties of an A357 aluminium alloy component formed by New Rheocasting. The effect that the evolution of silicon, during the solution treatment at various times, has on the mechanical properties was also examined. The mechanical properties were evaluated performing tensile tests, fractographical analysis and hardness tests. The microstructural characterization was made using optical and electronic microscopy.Item High performance automotive and railway components made from novel competitive aluminium composites(2003-07-01) Goñi, J.; Egizabal, P.; Coleto, J.; Mitxelena, I.; Leunda, I.; Guridi, J. R.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoThe traditional materials encounter difficulties to comply with all the properties required by new components under service conditions. The automotive and the railway industries require low cost solutions to improve the final performance of components made from steel, cast iron, or even conventional aluminium alloys (e.g. clutch discs, brake discs, or pistons). Weight reduction, improvement in wear behaviour, high thermal conductivity, low coefficient of thermal expansion, and easy recycling are sought, among other characteristics, in order to obtain more efficient products leading to a reduction of pollutant emissions. The range of materials that can meet these requirements is presently very narrow and their final price is more expensive (e.g. aluminium matrix composites) than currently used materials. In this paper a new low cost metal matrix composite that has been used to produce pistons, clutch discs, and train brake discs is presented.Item High pressure die casting (HPDC) of advanced reinforced aluminium alloys(2004-06) Goñi, J.; Eguizabal, P.; Coleto, J.; Guridi, J. R.; Garitagoitia, I.; Garitagoitia, E.; Barbarias, E.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoAn advanced material based on a AlSi8Cu3Fe alloy reinforced with 6%wt. of Titanium Diboride (TiB2) particles was employed to produce demonstrator clutch discs and to compare the obtained properties with those of the corresponding non reinforced alloy. The new material was produced through an in-situ reaction in which two salts were incorporated into the aluminium alloy melt to produce the reinforcing particles through an exothermal chemical reaction. The material so formed was first used to obtain samples through the direct Squeeze Casting technology at lab scale. Afterwards, it was also employed to produce some demonstrator prototypes with a conventional industrial High Pressure Die Casting (HPDC) equipment. Results obtained with the reinforced material with the Squeeze Casting and HPDC technologies are presented and compared to those obtained with the corresponding non reinforced equivalent. The effect of the TiB2 particles was analysed in terms of enhancement of mechanical properties at high temperatures, thermal properties, processing, etc. Minor changes had to be implemented in the moulds and equipments used to produce the final samples and components. The melt was stirred in order to avoid the settling phenomenon that might have taken place due to the difference of the density of the particles and the alloy. The processing parameters had to be fixed in order to take into account the different viscosity, castability and solidification pattern of the new material. Information on the optimization of the casting processes and properties of the Squeeze Casting and HPDC samples obtained are shown.Item Last developments in novel production processes for metal matrix composites(2007) Goñi, J.; Sarriés, I.; Bárcena, J.; De Cortázar, M. García; Egizabal, P.; Coleto, J.; Centros PRE-FUSION TECNALIA - (FORMER); EXTREMAT; CIRMETAL; Tecnalia Research & Innovation; MercadoItem Microstructure-properties relationship of AS9U3/SiCp composites formed by sand and permanent mold casting(1997) Goñi, J.; Coleto, J.; García, A.; Palacios, J. K.; Castro, M. C.; Coupard, D.; Arriaran, J.; Centros PRE-FUSION TECNALIA - (FORMER); MercadoThe present work deals with the mechanical behaviour of a commercial AS9U3/SiCp composite formed by sand and permanent mold casting. The corresponding unreinforced matrix was also formed in the same conditions. As cast and heat treated (T6) tensile test specimens were machined and tested at room and 300° temperatures. The results showed a finer microstructure for both materials formed by permanent mold casting, with improved properties for the composite over those obtained for the unreinforced matrix, although this improvement was more clearly shown at 300°. The highest mechanical properties were obtained with the T6 heat treatment for both materials formed by permanent mold casting.Item Mise en forme des alliages d'aluminium à l'état semi-solide: Une technologie compétitive pour les pièces automobiles(2004-11) Goñi, J.; Eguizabal, P.; Lakehal, M.; Sarriés, I.; Akizu, A.; Landa, I.; Wielanek, L.; Azpilgain, Z.; Hurtado, I.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & InnovationThe achievement of lighter automotive components is an important driving force m the development and optimization of casting techniques. Among these, Thixocasting and Squeeze Casting of aluminium alloys are presently used in the production of security components. In the present work, several production routes and aluminium alloys are considered. A die has been designed to produce a standard security component an automotive brake caliper. Simulation studies have been carried out to detect possible filling or solidification problems during casting and to solve them beforehand. Afterwards, automotive components have been produced with both a commercial globular structured A357 alloy through a semi-solid technology (Thixocasting) and a conventional A357 alloy by Squeeze Casting. General considerations of both casting processes are presented and some specific problems encountered are outlined. For comparison purposes, the automotive component selected has been also manufactured by means of other conventional casting technologies: sand casting, gravity die casting and low pressure die casting. Components from both sets of experiments have been heat treated and metallographic samples from problematic areas of the component selected have been thoroughly analyzed. Mechanical properties have been measured from tensile samples and the results compared for the different casting techniques evaluated.Item New aluminium matrix composites manufactured by an in-situ process(2003) LePetitcorps, Y.; Zanardo, N.; Albingre, L.; Imielinska, K.; Coleto, J.; Goñi, J.; Egizabal, P.; Mercado; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & InnovationDuring the last two decades, several researches were devoted to synthetic aluminium matrix composites. 20 years after, their field of applications is very restrictive. Many reasons can explain this fact: (1) the constituents are expensive (mainly the fibres), (2) the quality of fabrication is difficult to get mainly due to the non-wetting behaviour of the reinforcement-matrix couple, (3) fibre and matrix are not in thermodynamic equilibrium and the chemical reaction is always present during the fabrication of the composite or in service. These materials are thus not at all stable and expensive. In this work, we propose the preparation of an Al matrix composite by the in-situ precipitation of the reinforcing phase. This material has the advantage to be stable and recyclable. Due to the low melting point of aluminium, the foundry technique has been chosen for the preparation of these composites. The difficulty was to find the right reinforcement. Thus, a selection of the material procedure has been found to be very powerful and useful to find without any a priori a new reinforcement for the aluminium alloy matrix. Fe and Cr powders were selected for their ability to react with the Al-Si hypereutectic alloy. Elongated precipitates of intermetallic phase Al4FeSi or Al9Fe2Si2 were in situ formed in the Al-Si matrix by stir casting. The aspect ratio (L/d) is quite important (25 to 100) and the volume fraction of the crystals is in the range of 15% in this work. The platelet shape of the crystals is supposed to improve the creep behaviour and stiffness of the Al alloy. The reaction with Cr leads to the precipitation of large crystals of the cubic Al13Si4Cr4 compound. This composite seems to be more appropriate for tribological applications.Item Novel electronic packages made of highly loaded SiC particle aluminium based composites for space applications(2003) Coleto, J.; Maudes, J.; Goñi, J.; Marcos, J.; Calvin, J.; Costas, F.; Mercado; PRINTEX; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & InnovationA novel method for manufacturing AMC based packages for Monolithic Microwave Integrated Circuits (MMIC) applications has been developed by INASMET FOUNDATION and MIER COMUNICACIONES S.A. for space applications. Major problems associated to conventional Kovar or Copper Tungsten packages for electronic applications are poor heat dissipation and heavy weight. Based on the increasing need for high power dissipation and higher electronic components density in electronic devices for space applications (Phase arrays, etc), the present work has targeted the development of a new manufacturing process of multicavity packages made of aluminium matrix composites (AMCS) highly loaded with SiC particles, in which heat dissipation is notably increased and weight is lowered. Manufacturing method and new AMCS are more competitive in terms of properties/price ratio, in comparison with similar materials presently produced by metal infiltration techniques, due to the simplicity and high productivity of the novel shaping technology developed. Multicavity packages and cover lids were manufactured through a near net shape technology. Machining to net shape is performed with PCD tools to get requirements of finishing. A double Ni/Au electroplating is performed on the packages before integration of hybrid microwaves and package closing. External visual inspection, electrical and thermal resistance measurements are performed in order to confirm the validity of hybrid microwaves integration.Item Processing of aluminium alloys in semi-solid state: A competitive technology for automotive components(2004) Goñi, J.; Eguizabal, P.; Lakehal, M.; Sarriés, I.; Akizu, A.; Landa, I.; Wielanek, L.; Azpilgain, Z.; Hurtado, I.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & InnovationThe achievement of lighter automotive components is an important driving force in the development and optimization of casting techniques. Among these, Thixocasting and Squeeze Casting of aluminium alloys are presently used in the production of security components. In the present work, several production routes and aluminium alloys are considered. A die has been designed to produce a standard security component: an automotive brake caliper. Simulation studies have been carried out to detect possible filling or solidification problems during casting and to solve them beforehand. Afterwards, automotive components have been produced with both a commercial globular structured A357 alloy through a semi-solid technology (Thixocasting) and a conventional A357 alloy by Squeeze Casting. General considerations of both casting processes are presented and some specific problems encountered are outlined. For comparison purposes, the automotive component selected has been also manufactured by means of other conventional casting technologies: sand casting, gravity die casting and low pressure die casting. Components from both sets of experiments have been heat treated and metallographic samples from problematic areas of the component selected have been thoroughly analyzed. Mechanical properties have been measured from tensile samples and the results compared for the different casting techniques evaluated.Item Ventilated brake discs manufactured in aluminium matrix composites and hypereutectic aluminium alloys(2003) Goñi, J.; Coleto, J.; Egizabal, P.; Rubio, A.; García, A.; Sanchez, J.; Centros PRE-FUSION TECNALIA - (FORMER); Mercado; Tecnalia Research & InnovationTwo different aluminium alloy materials have been used to produce ventilated brake discs, on one hand, AS17G0.6 hypereutectic alloy and on the other hand, AS7G0.6 reinforced with 20% in wt. of SiC particles. The casting production technique used has been Low Pressure Casting (LPC) and some of the brake discs have been heat treated using a T6 treatment. Once the ventilated brake discs were produced and machined, they were tested in a dynamometer in order to compare the performance under service conditions of the aluminium alloy and grey cast iron (GCI) discs currently used in the market.