Abstract: The invention relates to a composite material combining a magnesium alloy containing zirconium with a carbon reinforcement, as well as to its production process.According to the invention, such a composite material is prepared by the infiltration of a reinforcement formed from graphite or carbon fibres by a liquid magnesium alloy containing 0.3 to 1% by weight zirconium at a temperature of 650.degree. to 850.degree. C.Under these conditions, on said fibres is formed a zirconium carbide layer containing magnesium in solid solution and e.g. complying with the formula ZrC.sub.x Mg.sub.y with 0.3<x<1 and 0.02<y<0.12, which leads to the wetting of the fibres by the melted magnesium and to a good adhesion between the fibres and the matrix, without any deterioration to the mechanical characteristics of the fibres.

Abstract: To manufacture a reflector formed by a reflective metallic layer on a metallic matrix composite support, a metallic layer having a reflective surface whose shape is at least approximately identical to the required geometrical shape is disposed on a mold surface having a geometrical shape complementary to the required geometrical shape of the reflector. Fibers to constitute the composite support are draped on the metallic layer. They are metallized by the metallic or intermetallic material to form the metallic matrix. This layer and the metallized fibers are subjected to temperature and pressure conditions adapted to press the reflective surface strongly against the mold surface and to cause diffusion welding of the layer with the metallized fibers and of the metallized fibers with themselves so as to integrate the layer to the composite support during consolidation of the latter.

Abstract: The invention relates to a composite material comprising a matrix mainly constituted by an intermetallic compound of the AlNi type containing in solid solution 1.5 to 30 atom % silicon and a reinforcement formed from silicon carbide (SiC) particles dispersed in said matrix.In said material, the presence of silicon leads to a thermodynamic equilibrium system no longer evolving by SiC reinforcement/matrix chemical reaction when raised to a high temperature.This material can be prepared by conventional processes by adding the silicon to the starting material or by carrying out a limited reaction during the preparation between an AlNi matrix and the silicon carbide particles.

Abstract: According to the present invention, a composite material including a magnesium alloy containing zirconium with a graphite or carbon fiber reinforcement is provided. The material is prepared by infiltration of the reinforcement by a liquid magnesium alloy containing 0.3 to 1% by weight zirconium at a temperature of 650.degree. to 850.degree. C. Under these conditions, a zirconium carbide layer containing magnesium in solid solution is formed on the fibers. This results in wetting of the fibers by melted magnesium and good adhesion between the fibers and the matrix, without any deterioration in the mechanical characteristics of the fibers.

Abstract: To manufacture a reflector formed by a reflective metallic layer on a metallic matrix composite support, a metallic layer having a reflective surface whose shape is at least approximately identical to the required geometrical shape is disposed on a mold surface having a geometrical shape complementary to the required geometrical shape of the reflector. Fibers to constitute the composite support are draped on the metallic layer. They are metallized by the metallic or intermetallic material to form the metallic matrix. This layer and the metallized fibers are subjected to temperature and pressure conditions adapted to press the reflective surface strongly against the mold surface and to cause diffusion welding of the layer with the metallized fibers and of the metallized fibers with themselves so as to integrate the layer to the composite support during consolidation of the latter.

Abstract: A high speed rotor for use with a flywheel comprising a hub, a rim centered with respect to said hub, connecting arms, each in the form of an elongated loop connecting said rim to said hub. The inner end of each loop is centered and maintained against the centrifugal force through a central member belonging to the hub while the outer end of said loop is bearing against the rim, a mass included within said outer end providing elongation of the loop under the effect of centrifugal force to ensure constant contact between said connecting arms and said rim.