A method of forming a ceramic matrix composite includes forming a preform by weaving a plurality of warp tows with a plurality of weft tows, weaving a plurality of fugitive yarns into a region of the preform in at least one of a warp position or weft position, and subsequently, decomposing the fugitive yarns to transform the region into a pre-weakened region, the pre-weakened region having a higher porosity than a remainder of the preform.

The invention relates to a method for the treatment of silicon carbide fibers, comprising a step involving the chemical treatment of fibers with an aqueous acid solution containing hydrofluoric acid and nitric acid but free of acetic acid in order to remove the silica present on the surface of fibers and to form a layer of microporous carbon. The invention also relates to a method for the production of a fibrous preform, comprising the formation of a fibrous structure comprising treated silicon carbon fibers and the use of said preform for the production of a part made from composite material.

Woven fiber preforms are disclosed which have a base section and one or more leg sections positioned the base section, The base section and the leg sections together are a made of a single three-dimensional woven fiber structure comprising warp and weft fiber tows. The woven structure includes connecting weft tow sections that connect the base section to each of the leg sections. The connecting weft tow sections include through-the-thickness tow regions that pass from a leg section through the thickness (height) of the base section.

A fiber preform for manufacturing a component made of composite material, the fiber preform exhibiting three-dimensional weaving and having a usable zone extending between two edge zones, the fiber preform further including at least two tracer filaments woven in the one same, weft or warp, direction and belonging to two different layers of weft filaments or warp filaments, each one being present in a distinct edge zone, the tracer filaments having a second composition different from the first composition, each tracer filament creating at least one textile marker on the surface of the fiber preform, a textile marker being created by the appearance of the tracer filament on the surface of the preform.

In a method for producing polycarbosilane by a liquid phase-gas phase thermolysis condensation method, provided is a method for producing polycarbosilane for silicon carbide fiber production having fewer processes than known production methods. The method for producing polycarbosilane for silicon carbide fiber production according to an aspect of the present invention includes: a polycarbosilane synthesis step of synthesizing polycarbosilane having a weight average molecular weight of 9000 or greater, the polycarbosilane synthesis step including the processes of: heating a raw material containing a cyclic silane compound at a first temperature to generate a gas phase, heating the gas phase at a second temperature higher than the first temperature to generate polycarbosilane, and by cooling the polycarbosilane to return to the raw material and heating at the first temperature, increasing a molecular weight of the polycarbosilane.

A method of forming a ceramic matrix composite includes forming a preform by weaving a plurality of warp tows with a plurality of weft tows, weaving a plurality of fugitive yarns into a region of the preform in at least one of a warp position or weft position, and subsequently, decomposing the fugitive yarns to transform the region into a pre-weakened region, the pre-weakened region having a higher porosity than a remainder of the preform.

Provided is a fiber material suitable for a method for producing a silicon carbide fiber with excellent mechanical properties. Polycarbosilane for silicon carbide fibers according to the present invention has a weight average molecular weight (Mw) of 10000 or more and 16000 or less, a number average molecular weight (Mn) of 1500 or more and less than 6000, and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 2.0 or more and less than 4.5 and is a reaction product from a composition containing a cyclic silane compound. In a method for producing the polycarbosilane for silicon carbide fibers according to the present invention, polycarbosilane is synthesized using a composition containing a cyclic silane compound, and the reaction product is subjected to molecular weight adjustment treatment.

A method for manufacturing a propeller blade or vane made of composite material, includes making a single-piece fibrous blank by three-dimensional weaving between warp yarns and weft yarns, including an airfoil part and a root part including a non-interlinking, the root part including at least one changing sub-area in which the number of weft yarns crossing on either side of the non-interlinking increases gradually from the airfoil part to the free end of the root part, shaping the fibrous blank to obtain a fibrous preform, densifying the preform by a matrix to obtain a propeller blade or vane made of composite material.

A method for producing a polycarbosilane (PCS) for silicon carbide fibers, the method does not include adjusting a molecular weight of PCS, the method comprises the steps of: (a) heating a composition containing a cyclic silane compound in a liquid-phase reaction vessel 1 to vaporize the composition; (b) heating the composition in gaseous form obtained by the step (a) to produce a PCS; and (c) returning the PCS produced by the step (b) to the liquid-phase reaction vessel 1, and returning gaseous components having cooled to the liquid-phase reaction vessel 1. Each of the steps is repeated, thereby producing a PCS having a number average molecular weight (Mn) of 1250 or more and less than 6000 and a ratio (Mw/Mn) of a weight average molecular weight (Mw) to the number average molecular weight (Mn) of 4.5 or more and 20.0 or less.

A fibrous preform for the manufacture of a part made of composite material, the fibrous preform having a three-dimensional weave includes a plurality of layers of weft yarns and a plurality of layers of warp yarns which extend in a direction perpendicular to the direction of the weft yarns, wherein each weft yarn connects warp yarns of multiple layers, the weft yarns and the warp yarns being woven according to a regular weave, the fibrous preform including, on the surface, one or more reference patterns that extend in a particular direction of the fibrous preform, a reference pattern being created by a local variation in the weave.