Browsing by Author "Silvain, J. F."
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Item Analysis of strengthening mechanisms of the AlCu5MgTi alloy reinforced with TiB2 particulates(European Conference on Composite Materials, ECCM, 2014) Egizabal, P.; Garcia De Cortazar, M.; Torregaray, A.; Silvain, J. F.; Tecnalia Research & Innovation; CIRMETALThe present study was devised to analyse the strengthening mechanisms of a reinforced AlCu5MgTi alloy. TiB2 particulates were created into the aluminium alloy in an in situ process were titanium and boron containing salts added into melt aluminium reacted and formed TiB2 particulates following long known reactions. The obtained material was subsequently cast in order to obtain samples and characterise them. The metallurgical analysis showed that, as foreseen, TiB2 particulates play an important role in the precipitation of the different phases of the alloys as well as in the reduction of grain size and porosity. It was clearly shown that the elongation values got increased (46% in the as cast condition and 63% in the T6 thermally treated specimens). The observed microshrinkages were also much less abundant in the case of the reinforced materials. This latter effect is related to the shortening of the solidification interval.Item Fabrication and characterisation of graphite/alumina reinforced copper composites(2000-12) Coupard, D.; Goni, J.; Silvain, J. F.; Centros PRE-FUSION TECNALIA - (FORMER)The infiltration of graphite/alumina preforms with a bronze alloy has been investigated taking into account the influence of the binder type, the graphite/alumina content in the preform and the percentage of binder in water. The preforms showing an acceptable rigidity have been infiltrated with a CuSn12 bronze alloy by squeeze casting considering two different pouring temperatures. The composite produced has been characterised in terms of density, Brinell hardness, coefficient of thermal expansion, as well as friction and wear behaviour. The coefficient of friction for the bronze matrix composite is around 0.17, being three times lower than that shown by the unreinforced copper alloy. Given the contact geometry (ball of steel against a planar sample) and testing conditions (20°C, dry sliding, 40% humidity), the composite wear rate is around twenty times lower that of the bronze, being 10-6mm2/kg for the composite and 2 × 10-5 mm22/kg for the bronze.Item Magnetic molding foundry process of non ferrous and ferrous alloys(2005) Geffroy, P. M.; Goni, J.; Lakehal, M.; Beaugnon, E.; Silvain, J. F.; Centros PRE-FUSION TECNALIA - (FORMER)Magnetic molding technology, is a good alternative process in order to improve the metallurgical quality and dimensional tolerances of the final components that are presently produced through Lost Foam process. The first development of the magnetic molding process was performed at the same time of the lost foam process more than thirty years ago but it has never reached the same industrial development. The purpose of this study is to introduce the magnetic molding process, and to define the advantages and the characteristics of this process. Particular attention is given to the comparative results obtained with the lost foam and the magnetic molding processes with aluminum and grey cast iron. Eventually, the main factors involved in the magnetic molding process are discussed.