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: 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 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 fabricating a complex part out of composite material including three-dimensional woven fiber reinforcement densified by a matrix, the method including three-dimensionally weaving a continuous fiber strip including a succession of fiber blanks for preforms of a plurality of parts that are to be fabricated; subsequently cutting individual fiber blanks out from the strip, each blank being a one-piece blank; shaping a cut-out blank to obtain a one-piece fiber preform having a shape that is close to the shape of a part that is to be fabricated; consolidating the preform in the desired shape; and densifying the consolidated preform by forming a matrix by chemical vapor infiltration.

Abstract: The method comprises: using chemical vapor infiltration to form a first continuous interphase on the fibers of a fiber structure made of refractory fibers, the interphase having a thickness of no more than 100 nanometers; impregnating the fiber structure with a consolidation composition comprising a carbon or ceramic precursor resin; forming a fiber preform that is consolidated by shaping the impregnated fiber structure and using pyrolysis to transform the resin into a discontinuous solid residue of carbon or ceramic; using chemical vapor infiltration to form a second continuous interphase layer; and densifying the preform with a refractory matrix. This preserves the capacity of the fiber structure to deform so as to enable a fiber preform to be obtained that is of complex shape, while nevertheless guaranteeing the presence of a continuous interphase between the fibers and the matrix.

Abstract: A reinforcing fiber structure woven as a single piece for fabricating a composite material part, the fiber structure having an internal portion or core (72), and a portion adjacent to an outside surface of the structure, or skin (74, 76), and the fiber structure being formed by a three-dimensional weaving in its core using at least one weave selected from an interlock weave and a multilayer weave, and by weaving at its skin with a weave of satin type that is different from the weave in the core the weaving at the skin being of the multilayer type or of the two-dimensional type.

Abstract: A method of fabricating a composite-material turbomachine blade having platform incorporated therein includes separately making a blade platform element that includes rigidified fiber reinforcement and that has a shape close to that of a platform of the blade to be fabricated, with at least one opening being formed through the platform element. The opening has the shape of the profile of the airfoil of the blade to be fabricated. Three-dimensional weaving is used to make a flexible fiber blank as a single piece that includes blade airfoil-and-root preform portions. The platform element is engaged, via its opening, on the flexible fiber blank while deforming it so as to assemble the platform element with the fiber blank. The fiber blank is shaped together with the platform element assembled thereon to obtain a blade preform of a shape that is close to the shape of the blade to be fabricated. After shaping, the blade preform is consolidated in its shape in a shaper.

Abstract: A method of fabricating a thermostructural composite material part includes making a fiber preform formed of yarns or tows and impregnated by a consolidating composition containing a carbon- or ceramic-precursor, transforming the carbon- or ceramic-precursor by pyrolysis, and then densifying the preform by chemical vapor infiltration. A consolidating composition is used that additionally contains refractory solid fillers in the powder form presenting mean grain size less than 200 nanometers and leaving, after pyrolysis, a consolidated solid phase in which the carbon or the ceramic derived from the precursor occupies a volume representing 3% to 10% of the apparent volume of the preform, and the solid fillers occupy a volume representing 0.5% to 5% of the apparent volume of the preform.

Abstract: A method of making a fiber structure by multilayer three-dimensional weaving, the fiber structure having a thickness in a direction perpendicular to the warp and weft directions that varies along the warp direction while conserving the same number of warp yarns that are woven at all points of the fiber structure along the warp direction, wherein during a transition in the warp direction from a first portion of the fiber texture to a second portion of the fiber texture having a thickness that is greater than the thickness of the first portion, the number of warp planes is decreased and the number of layers of warp yarns is increased without changing the number of warp yarns, by constituting at least one warp plane in the second portion with warp yarns taken from at least two different warp planes in the first portion.

Abstract: A turbine ring assembly for a gas turbine, the assembly having a complete ring forming a single piece of ceramic matrix composite material (CMC), a metal structure for supporting the CMC ring having metal annular supports between which the CMC ring is placed while allowing differential expansion at least in a radial direction between the CMC ring and the annular supports, an arrangement for centering the CMC ring, and at least one element for preventing turning of the CMC ring about its axis.

Abstract: An environmental barrier is formed on a substrate (10) of ceramic matrix composite material and comprises an outer anticorrosion protection layer (12) containing a compound of the type comprising an aluminosilicate of an alkali, or an alkaline-earth, or a rare-earth element. A bond sub-layer (14) is formed between the substrate (10) and the protection layer (12), the composition of the bond sub-layer varying from substantially pure silicon to substantially pure mullite between an inner face beside the substrate and an outer face, with the silicon content decreasing and the mullite content increasing.

Abstract: A fiber reinforcing texture woven as a single part for fabricating a composite material part having an inner portion, or core, made by three-dimensional weaving with yarns made up from discontinuous fibers, and a portion adjacent to an outside surface, or skin, made by weaving with yarns made up from continuous filaments.

Abstract: A fiber reinforcing texture woven as a single part for fabricating a composite material part having an inner portion, or core, made by three-dimensional weaving with yarns made up from discontinuous fibers, and a portion adjacent to an outside surface, or skin, made by weaving with yarns made up from continuous filaments.

Abstract: A fiber reinforcing texture (10) woven as a single part for fabricating a composite material part having an inner portion (12), or core, made by three-dimensional weaving with yarns made up from discontinuous fibers, and a portion (14, 16) adjacent to an outside surface, or skin, made by weaving with yarns made up from continuous filaments.

Abstract: A turbine ring assembly for a gas turbine includes a one-piece split ring (10) of ceramic matrix composite (CMC) material, a CMC wedge-shaped part (20) having flanks in contact with the ends of the ring, on either side of the split, so as to close the ring, and an annular metal support structure (40) surrounding the CMC ring and in contact therewith over the major fraction of its outline, the CMC ring being mounted with prestress in the metal structure, at least one element (26) exerting a resilient return force on the wedge-shaped part to keep it in contact with the ends of the CMC ring when the split opens under the effect of differential expansion between the annular metal structure and the CMC ring, and at least one element for preventing the CMC ring from turning about its axis.

Abstract: The method comprises: using chemical vapor infiltration to form a first continuous interphase on the fibers of a fiber structure made of refractory fibers, the interphase having a thickness of no more than 100 nanometers; impregnating the fiber structure with a consolidation composition comprising a carbon or ceramic precursor resin; forming a fiber preform that is consolidated by shaping the impregnated fiber structure and using pyrolysis to transform the resin into a discontinuous solid residue of carbon or ceramic; using chemical vapor infiltration to form a second continuous interphase layer; and densifying the preform with a refractory matrix. This preserves the capacity of the fiber structure to deform so as to enable a fiber preform to be obtained that is of complex shape, while nevertheless guaranteeing the presence of a continuous interphase between the fibers and the matrix.

Abstract: The method comprises: using chemical vapor infiltration to form a first continuous interphase on the fibers of a fiber structure made of refractory fibers, the interphase having a thickness of no more than 100 nanometers; impregnating the fiber structure with a consolidation composition comprising a carbon or ceramic precursor resin; forming a fiber preform that is consolidated by shaping the impregnated fiber structure and using pyrolysis to transform the resin into a discontinuous solid residue of carbon or ceramic; using chemical vapor infiltration to form a second continuous interphase layer; and densifying the preform with a refractory matrix. This preserves the capacity of the fiber structure to deform so as to enable a fiber preform to be obtained that is of complex shape, while nevertheless guaranteeing the presence of a continuous interphase between the fibers and the matrix.

Abstract: An assembled annular combustion chamber comprises an annular inner wall and an annular outer wall made of ceramic matrix composite material together with a chamber end wall connected to the inner and outer walls and provided with orifices for receiving injectors. Elastically-deformable link parts connect the inner wall and the outer wall of the chamber to inner and outer casings that are made of metal. The assembly formed by the inner wall, the outer wall, and the combustion chamber end wall is subdivided circumferentially into adjacent chamber sectors, each sector being made as a single piece of ceramic composite material and comprising an inner wall sector, an outer wall sector, and a chamber end wall sector. The link parts connect the inner metal casing and the outer metal casing respectively to each inner wall sector of the combustion chamber and to each outer wall sector of the chamber. The chamber end wall sectors are in contact with a one-piece ring to which they are connected.

Abstract: An assembled annular combustion chamber comprises an annular inner wall and an annular outer wall made of ceramic matrix composite material together with a chamber end wall connected to the inner and outer walls and provided with orifices for receiving injectors. Elastically-deformable link parts connect the inner wall and the outer wall of the chamber to inner and outer casings that are made of metal. The assembly formed by the inner wall, the outer wall, and the combustion chamber end wall is subdivided circumferentially into adjacent chamber sectors, each sector being made as a single piece of ceramic composite material and comprising an inner wall sector, an outer wall sector, and a chamber end wall sector. The link parts connect the inner metal casing and the outer metal casing respectively to each inner wall sector of the combustion chamber and to each outer wall sector of the chamber. The chamber end wall sectors are in contact with a one-piece ring to which they are connected.

Abstract: An environmental barrier for a substrate of ceramic matrix composite material containing silicon, in particular containing SiC, is formed by an anticorrosion protection layer containing an aluminosilicate type compound of an alkali or alkaline-earth or rare earth element, e.g. BSAS, with a chemical barrier forming layer of aluminum nitride being interposed between the substrate and the anticorrosion protection layer.