Abstract: Fabricating a composite material part comprises the steps of making a consolidated fiber preform, the fibers of the preform being carbon or ceramic fibers that are coated in an interphase formed by at least one layer of pyrolytic carbon (PyC) or of boron-doped carbon (BC). Obtaining a partially densified consolidated fiber preform, where partial densification comprises forming a first matrix phase on the interphase, the first matrix phase comprising a plurality of layers of self-healing material alternating with one or more layers of PyC or of BC. Continuing densification by dispersing carbon and/or ceramic powder within the partially densified consolidated preform and by infiltrating molten silicon or a liquid composition formed for the most part of silicon.

Abstract: Multilayer weaving is used to form a fiber blank having a longitudinal direction corresponding to the longitudinal direction of the vane to be made and comprising across its thickness a first woven portion with a plurality of layers of yarns interlinked by weaving, and also a second and third woven portions. The first portion is situated between the second and third portions and interlinked thereto by weaving over only a fraction of its longitudinal dimension. A preform for the vane is formed by folding out, on either side of the first portion, segments of the second and third portions not interlinked with the first portion, by shaping the first portion to form a preform portion for the airfoil of the vane, and by shaping the folded-out segments of the second and third portions to form preform portions for the inner and outer platforms of the vane to be fabricated.

Abstract: A normally closed electric switch having a sliding assembly that is actuated to open the switch, e.g. by a pyrotechnic gas generator. Prior to actuation, a conductive portion of the sliding assembly (21) is in tight contact with two rings (13a, 14a) that are axially offset on the same axis, belonging respectively to two electrically conductive tabs (13, 14), and after the actuator has been triggered, the upstream tab (13) is separated from the conductive portion of the sliding assembly. According to the invention, sliding assembly comprises a tube split by a slot extending along its entire length, and the conductive portion of the sliding assembly is constituted by all or part of said split tube, the clamping force between the conductive portion and the primary electrically conductive tabs being provided by the resilience of the split tube.

Abstract: A method of smoothing the surface of a ceramic matrix composite material part that presents a surface that is undulating and rough. The method includes depositing a refractory vitreous coating on the surface of the part, the vitreous coating essentially containing silica, alumina, baryte, and lime.

Abstract: A method of assembling together by brazing first and second parts made of composite material, each of the first and second parts having an assembly face for brazing with the assembly face of the other part, the method including making at least one perforation in the assembly face of the first part; interposing capillary elements between the assembly faces of the first and second parts made of composite material; placing the first and second parts facing each other while inserting a peg in each perforation of the first part; placing a brazing composition in contact with a portion of the capillary elements; and applying heat treatment to liquefy the brazing composition so as to cause the molten brazing composition to spread by capillarity between the assembly faces of the composite material parts.

Abstract: The main subject of the present invention is a process for processing a paste (5) containing a solid charge (C) with a view to extracting at least one part of said solid charge (C). Said process comprises continuously: mixing, in a mixer (8), said paste (5) with a liquid solvent (3), a solvent for said at least one part of said solid charge (C), with a view to dissolving, at least partially, said at least one part of said solid charge (C) in said solvent (3); recovering, after said mixing, a biphasic system (15) comprising, on the one hand, a solution (3?) enclosing at least one fraction of said at least one part of said solid charge (C), dissolved in said solvent (3), and on the other hand, a solid residue (5?) of said paste (5); and then, separating said solution (3?) and said solid residue (5?) of said paste (5).

Abstract: A refractory material that can withstand high temperatures in an oxidizing medium and containing at least: a first constituent corresponding to hafnium, or to a non-oxide compound of hafnium, or circular in a or a non-oxide compound of zirconium, or corresponding to a mixture of at least two metals and/or compounds selected from hafnium a non-oxide compound of hafnium, zirconium, and a non-oxide compound of zirconium; a second constituent corresponding to the boron or to a non-oxide compound of boron, or corresponding to a mixture of boron and a non-oxide compound of boron; and a third constituent corresponding to a rare earth RE or to a non-oxide compound of the rare earth RE, or corresponding to a mixture of rare earth RE and a non-oxide compound of the rare earth RE, where RE is selected from scandium, yttrium, and the lanthanides. The material contains neither silicon nor a compound of silicon.

Abstract: The present invention provides a process for obtaining a charge of hexanitrohexaazaisowurtzitane crystals having rounded morphology. It also provides said charge, the energetic material comprising it, and a process for manufacturing said material. Said process for obtaining said charge comprises: preparing a saturated solution of any polymorphic form of hexanitrohexaazaisowurtzitane in a mixture comprising both an organic solvent for said hexanitrohexaazaisowurtzitane and an organic nonsolvent for said hexanitrohexaazaisowurtzitane, said solvent being more volatile than said nonsolvent; seeding this saturated solution with a few hexanitrohexaazaisowurtzitane crystals; and then concentrating the seeded, saturated solution by at least partial evaporation of the solvent, said evaporation of the solvent being performed at a temperature of between 35° C. and 15° C.

Abstract: A refractory material withstanding high temperatures in an oxidizing medium contains at least hafnium boride and tantalum boride, hafnium and tantalum being present in the refractory material exclusively in compound form.

Abstract: A pyrotechnic gas generator for driving an actuator includes a body defining a combustion chamber housing a main pyrotechnic charge, and an ignitor for initiating combustion of the main pyrotechnic charge. The pyrotechnic gas generator includes at least one delay chamber adapted to communicate with the combustion chamber via at least one inlet orifice, and the delay chamber is provided with at least one outlet orifice for passing gas out from the gas generator. The at least one outlet orifice is provided with a seal adapted to pass from a closed state to an open state when the pressure inside the delay chamber reaches a rupture limit pressure.

Abstract: A device for monitoring a viscoelastic material by subjecting the sample to vibration and analyzing the response of the sample to such vibration. According to the invention, the sample (13) is placed in a chamber (20) situated between a vibration source (22) and a vibration sensor (25), these elements being pressed towards each other by means (35, 39) for applying initial mechanical loading.

Abstract: A rotor disk blade for a turbine engine, the blade being made of composite material including fiber reinforcement obtained by multilayer weaving of yarns and densified by a matrix. The blade has a portion constituting an airfoil and a blade root forming a single piece, the blade root having two substantially plane opposite lateral flanks that are formed respectively extending the pressure side surface and the suction side surface of the airfoil. The blade root is clamped between two metal plates fastened against the lateral flanks of the blade root by a bolt and a nut passing through the plates and the blade root. The bolt has a head bearing against one of the two plates. The nut has a head bearing against the other plate.

Abstract: A thermostructural composite material part including carbon or ceramic fiber reinforcement densified by a matrix having at least one thin portion in which: the thickness of the part is less than 2 mm, or indeed less than 1 mm; the fiber reinforcement is made as a single thickness of multilayer fabric made of spread yarns having a weight of not less than 200 tex; the fiber volume ratio lies in the range 25% to 45%; and the ratio between the number of layers of the multilayer fabric and the thickness in millimeters of the part is not less than four.

Abstract: An assembly comprising first and second parts made of composite material held one against the other by at least one fastener system comprising a bolt having a flat head from which there extends a threaded portion, and a nut having a flat head from which there extends a shank including tapping suitable for co-operating with the threaded portion of the bolt. The head of the bolt bears against a countersink formed in the first part. The head of the nut bears against a countersink formed in the second part. The fastener system is suitable, during axial expansion of the fastener system, for causing each head to tilt towards the countersink in which it is housed.

Abstract: An aeroengine exhaust cone is arranged to extend from upstream to downstream along a longitudinal axis. The cone comprises a structural core of composite material made up of an axisymmetric part having an upstream endpiece at its upstream end and a downstream endpiece at its downstream end. The core provides structural strength to the cone. The cone has an acoustic attenuation system made of composite material and fastened on the structural core.

Abstract: The main subject of the present invention is solid pyrotechnic gas generator compounds, the composition of which contains: guanidine nitrate, basic copper nitrate, and at least one inorganic titanate, the melting point of which is above 2100 K. Said compounds are perfectly suitable for use in frontal airbags.

Abstract: A method of smoothing the surface of a ceramic matrix composite part presenting a surface that is undulating and rough. The method includes forming a ceramic coating on the surface of the part, the coating being made by applying a liquid composition on the surface of the part, the composition containing a ceramic-precursor polymer and a factory solid filler, curing the polymer, and transforming the cured polymer into ceramic by heat treatment. The method further includes impregnating the ceramic coating with a liquid metallic composition.

Abstract: A space propulsion module in particular for fitting to spacecraft such as satellites, probes, or indeed the upper stages of rockets. According to the invention, the space propulsion module comprises a solid propellant chemical thruster (10) having a main body (11), and at least one electric thruster (30), said at least one electric thruster (30) being mounted on said main body (11) of the solid propellant chemical thruster (10).

Abstract: The present invention relates to a gas generator (10) comprising a body (12) delimiting at least one part of a combustion chamber (20), said part housing a primary pyrotechnic charge (16) adapted to generate gases in the combustion chamber (20) when said charge is initiated in combustion, and a slide valve (60) located outside said body (12) and defining with the latter a second chamber (66) housing a secondary pyrotechnic charge (74) whereof the self-ignition temperature is less than that of the primary pyrotechnic charge (16). A gas flow channel (50) for flowing gas out of the combustion chamber (20) is formed in the body (12). According to the invention, the slide valve (60) blocks this channel when it is in a first position, and under the effect of gases released by said secondary pyrotechnic charge (74), the slide valve is adapted to move to a second position wherein the channel (50) is no longer sealed off, allowing the gases contained in the combustion chamber (20) to flow outwards to the exterior.

Abstract: A roller for a high temperature annealing line includes a cylindrical shell and an axial support element and including a spindle at at least one of its ends, and first and second keys fastened to the axial support element and each arranged in a respective first or second through opening formed in the shell. The first key is mounted to bear against a first circumferential bearing surface of the first through opening while the second key is mounted against a second circumferential bearing surface of the second through opening opposite to the first circumferential bearing surface of the first through opening in a circumferential travel direction. The first key is mounted to bear against the second longitudinal bearing surface of the first through opening, while the second key is mounted against the first longitudinal bearing surface of the second through opening opposite to the second longitudinal bearing surface.