365 results about "Sic fiber" patented technology

The invention belongs to the technical field of nano porous materials, discloses a high-strength and low-thermal-conductivity SiC-TiO2 nanofiber aerogel and a preparation method thereof, and aims to solve the problems of insufficient structural stability, shear strength and high-temperature thermal conductivity of traditional ceramic aerogel. TiO2 nanorods are introduced onto a SiC nanofiber membrane by adopting an in-situ growth technology, and the high-strength and low-thermal-conductivity SiC-TiO2 nanofiber aerogel is prepared. And constructing the SiC nano composite fiber membrane into the layered porous ceramic nanofiber aerogel with a multilevel structure by combining a layer-by-layer stacking method with a directional freezing casting technology. TiO2 nanorods growing on the surface of the SiC fiber in situ serve as a secondary structure, so that the overall mechanical performance of the material is enhanced; the TiO2 nanorods have specific high infrared light reflection and scattering capabilities, so that the transmittance of the aerogel material to radiation is reduced, and the thermal radiation conduction in a high-temperature environment is effectively reduced. In addition, a silica sol binder is introduced between layers of the aerogel multilevel structure, stable bonding points are formed between fibers after calcination, and the mechanical stability is improved.

The invention discloses a high-entropy alloy silicon carbide nanofiber composite material and a preparation method and application thereof, a high-entropy alloy is loaded on silicon carbide nanofibers, compared with a carbon fiber material carrier, SiC fibers can form a compact SiO2 protective layer in a high-temperature aerobic environment, further oxidation failure of the internal structure can be prevented, and the high-entropy alloy silicon carbide nanofiber composite material is prepared. And meanwhile, SiC also has relatively high high-temperature stability and weather resistance, so that the high-entropy alloy silicon carbide nanofiber composite material can stably work in an extreme high-temperature oxidation environment (such as a spacecraft thermal protection system and an engine tail gas pipeline) of over 1000 DEG C, and perfectly adapts to a high-temperature wave-absorbing scene.

The invention belongs to the technical field of radar stealth materials and high-temperature electromagnetic protection, and particularly relates to design and a preparation method of a high-temperature-resistant wave-absorbing material based on alumina fibers. According to the material, a high-temperature-resistant ceramic precursor serves as a base body, a reinforcing phase is formed by alternately stacking alumina fiber cloth and an alumina fiber web tire containing chopped silicon carbide fibers, and a three-dimensional reinforcing structure is formed through a needling technology; the chopped silicon carbide fibers are directionally distributed in the net tire in a non-uniform mode, an enhanced area array with the local geometric regular pattern is constructed, the size and the arrangement period change in a gradient mode in the thickness direction, a vertical dielectric gradient structure is formed in the material, and multi-path propagation, reflection and polarization loss of electromagnetic waves are improved; the surface of alumina fiber cloth is coated with a ceramic interface layer, so that the interface bonding strength and thermal stability are improved; the ceramic matrix is densified for multiple rounds, so that the structure is compact; the material has excellent electromagnetic absorption performance, heat resistance and mechanical strength, and is suitable for high-temperature electromagnetic environments such as aerospace, missile bay sections and the like.

The invention relates to the field of composite material ultrathin laminated plates, in particular to a preparation method of a SiC fiber reinforced Ti-based composite material ultrathin laminated plate. The method comprises the following steps: plating Ti alloy on the surface of SiC fiber by using a physical vapor deposition method; the titanium alloy foil is subjected to acid pickling to remove a surface oxide layer and impurities; the plated fibers are tightly arranged to form a SiCf / Ti alloy plate, the upper surface and the lower surface of the SiCf / Ti alloy plate are bonded to a titanium alloy foil through an adhesive, and a foil-plate-foil prefabricated body is manufactured; sealing the periphery of the prefabricated body, covering gaskets on the upper surface and the lower surface of the prefabricated body, removing the adhesive from the prefabricated body, and placing the prefabricated body in a vacuum hot-pressing mold; and a hot-pressing process is adopted to realize densification composite molding of the laminated plate. According to the method, uniform distribution of SiC fibers is achieved, the mechanical property of the material is effectively improved, the surface flatness is good after the laminated plate is prepared, and the method is suitable for weight reduction application of aerospace structural parts such as skins and reinforcing ribs.

The invention belongs to the field of continuous SiC fiber reinforced metal matrix composite materials, and particularly relates to a SiCf / TiMoNb-Ti2AlNb / Ti2AlNb laminated composite material and a preparation method of the SiCf / TiMoNb-Ti2AlNb laminated composite material. The composite material is of a hot isostatic pressing composite structure of a precursor wire and a Ti2AlNb sheath outside the precursor wire, the precursor wire is formed by uniformly distributing SiC fibers in a TiMoNb-Ti2AlNb laminated alloy matrix, the volume fraction of the SiC fibers accounts for 40-55% of the total volume fraction of the SiCf / TiMoNb-Ti2AlNb / Ti2AlNb laminated composite material, and the composite material is good in combination, compact and free of holes. Through the introduction of the TiMoNb-Ti2AlNb lamination layer, the composite material can be compact under a relatively low hot isostatic pressure parameter, and the effect of improving the performance can be achieved after process parameters are optimized.

The invention discloses a preparation method of a toughening environmental barrier coating, and relates to a preparation method of a coating. The invention aims to solve the problem of poor fracture toughness of the existing environmental barrier coating. The method comprises the following steps: 1, pretreating a base material; 2, preparing a bonding layer; and 3, preparing the environmental barrier layer. The high-melting-point metal silicide prepared on the surface of the base material or the bonding layer compounded by the high-melting-point metal silicide and the rare earth silicate has excellent temperature resistance and good interface bonding strength, and due to the addition of the rare earth silicate, the expansion coefficient of the bonding layer is highly matched with that of the base material; according to the prepared yttrium oxide stabilized zirconia fiber, mullite fiber or silicon carbide fiber reinforced rare earth silicate environmental barrier layer, the fracture toughness of pure Yb2SiO5 is improved to 6.5 MPa.m < 1 / 2 >-8.0 MPa.m < 1 / 2 > from about 1.85 MPa.m < 1 / 2 >. The strengthening and toughening environmental barrier coating prepared by the invention has very important significance on development of thermal protection coatings of hot end parts of aircrafts with high thrust-weight ratios in China.

The invention belongs to the technical field of composite material preparation, and particularly relates to a preparation method of a SiCf / TiMoNb heterogeneous core material reinforced GH4169 composite material. The preparation method comprises the following steps: depositing a TiMoNb alloy matrix on the surface of SiC fiber by using a magnetron sputtering method to form a precursor wire, carrying out composite molding on the obtained precursor wire and a GH4169 sheath in a hot isostatic pressing manner, and carrying out diffusion bonding to form the composite material. The obtained composite material SiCf / TiMoNb / GH4169 has excellent unidirectional performance at high temperature, the tensile strength at 850 DEG C can reach 1057 MPa, and the high-temperature strength of GH4169 alloy is effectively improved. The prepared composite material is high in high-temperature strength and has good application prospects, and the adopted preparation process is mature in technology and little in pollution.

The invention provides a bionic hollow petal-shaped SiC fiber porous thermal insulation material as well as a preparation method and application thereof, and belongs to the technical field of thermal insulation materials. The preparation method comprises the following steps: taking a viscose-based carbon fiber felt as an initial structure template, dipping the carbon fiber felt in siloxane sol, taking out the carbon fiber felt, and carrying out suction filtration to remove redundant sol on the surfaces of carbon fibers; curing the impregnated carbon fiber felt, and carrying out heat treatment to obtain the carbon fiber felt of which the carbon fiber surface is covered with a uniform SiC coating; and carrying out thermal oxidation treatment on the carbon fiber felt with the SiC coating to obtain the bionic hollow petal-shaped SiC fiber porous thermal insulation material. Compared with a traditional sol-gel method, the method has the advantages of being short in preparation period, low in cost, small in volume shrinkage rate and the like, and the obtained bionic hollow petal-shaped SiC fiber porous heat insulation material has good rebound resilience and excellent high-temperature heat insulation performance and has wide application prospects in a high-temperature oxidation environment.

The invention provides a silicon carbide fiber reinforced ceramic-based composite material as well as a preparation method and application thereof, and belongs to the technical field of ceramic-based composite materials. The composite material comprises a silicon carbide fiber reinforced phase, a boron nitride interface layer and a silicon-based multiphase ceramic matrix from inside to outside, the silicon-based multiphase ceramic matrix comprises an infiltration reaction generation phase, an introduced ceramic particle phase and a silicon-containing binary alloy phase, and the infiltration reaction generation phase comprises a water-oxygen corrosion resistant phase, a silicon phase, a silicon carbide phase and a boride phase. The water oxygen corrosion resistant phase comprises a compound of boron and any element of yttrium, ytterbium, hafnium, molybdenum and aluminum, the boride phase comprises B12 (C, Si, B) 3, the bending strength of the composite material is larger than or equal to 600 MPa, and the fracture toughness of the composite material is larger than or equal to 19 MPa.m < 1 / 2 >. According to the preparation method, the matching property among the components of the composite material is optimized, the mechanical property of the composite material is improved, and a new thought and a process method are provided for preparing the high-strength and water-oxygen-corrosion-resistant ceramic matrix composite material.

The invention discloses a preparation method of a high-temperature-resistant wave-absorbing honeycomb sandwich structure in the technical field of wave-absorbing materials, which comprises the following steps: synthesizing a transition metal modified polycarbosilane precursor under the protection of inert gas, and performing high-temperature cracking to obtain a magnetic silicon carbide wave-absorbing agent; blending and grinding the wave-absorbing agent and high-temperature-resistant resin to prepare a wave-absorbing glue solution; after a honeycomb core material is formed by adopting inorganic fiber cloth, a wave-absorbing glue solution is loaded through a repeated dipping-drying process, and the high-temperature-resistant wave-absorbing honeycomb is obtained through gradient heat treatment. And finally, compounding and curing with the wave-transparent skin and the carbon fiber composite material through a high-temperature-resistant adhesive film. The sandwich structure is prepared on the basis of the composite material, and the magnetic silicon carbide wave-absorbing agent has the characteristics of high temperature resistance, low density, oxidation resistance and adjustable dielectric property; the phthalocyanine resin matrix is adopted, so that excellent formability and high-temperature stability are guaranteed; honeycomb nodes are sewn and reinforced by silicon carbide fibers, so that the problem of node cracking in a high-temperature environment is solved.

The invention relates to a modified silicon carbide fiber and a preparation method and application thereof, the modified silicon carbide fiber endows magnetic loss, and combines high strength and corrosion resistance of a geopolymer matrix to realize double improvement of mechanical properties and wave absorbing efficiency of concrete. Carbon fibers in conventional wave-absorbing concrete are replaced by modified silicon carbide fibers, so that on one hand, the wave-absorbing concrete has good oxidation resistance at high temperature, carbon emission is greatly reduced, and the wave-absorbing concrete has the advantages of energy conservation and environmental protection; and on the other hand, the defect that the performance is reduced at high temperature is overcome, and the modified silicon carbide fiber enables the magnetic loss of metal and the dielectric loss of a matrix to form a synergistic effect, so that the wave absorbing performance is greatly improved. The invention is suitable for green communication infrastructures, and has the characteristics of environmental protection, high durability and broadband wave absorption.

The invention discloses a preparation method of near-stoichiometric ZrB2 doped SiC fibers, which comprises the following steps: preparing a zirconium-containing multiphase ceramic precursor (PZMS) and polymethylsilane (PMS) into a PZMS / PMS mixed precursor, and blending the PZMS / PMS mixed precursor with spinning-grade polycarbosilane (PCS) to obtain a mixed precursor; the ZrB2-doped silicon carbide fiber with the C / Si atomic ratio close to an ideal value is obtained through the processes of melt spinning, electron beam / BCl3 crosslinking-heat treatment, hydrogen high-temperature pyrolysis, high-temperature sintering and the like in sequence, and regulation and control of fiber components are achieved.

The invention belongs to the technical field of conductive ceramics, and discloses a silicon nitride conductive ceramic material and a preparation method thereof.The method comprises the steps that a yttrium oxide, aluminum oxide and magnesium oxide ternary composite system is arranged, rare earth elements are doped, and a sintering aid is formed; a resistance adjusting agent is composed of a titanium nitride-titanium dioxide core-shell structure and silicon carbide fibers, and the silicon carbide fibers are directionally distributed and arranged in a magnetic field, so that efficient composition of the silicon nitride conductive ceramic material is achieved, and the effects of high bending resistance, high conductivity and low sintering temperature are achieved; forming the slurry; performing spark plasma sintering; conducting network directional regulation and control; the preparation method comprises the steps of raw material mixing and ball milling, post-treatment and performance optimization, a convenient preparation process can be formed, too many tedious steps are not needed, a ball mill used in raw material mixing and ball milling is further provided with a pre-grinding device for pre-grinding the materials, the subsequent ball milling quality is enhanced, and the situation that the materials are not completely ground is avoided.

The invention provides a silicon carbide fiber-copper composite bonding wire and a preparation method thereof, and relates to the technical field of electronic materials. The preparation method of the silicon carbide fiber-copper composite bonding wire comprises the following steps: pre-plating copper on the surface of silicon carbide fiber to obtain copper-coated silicon carbide fiber; laying copper-coated silicon carbide fibers to obtain a copper-coated silicon carbide fiber layer, then constructing a copper alloy layer on the copper-coated silicon carbide fiber layer by using composite copper powder, then arranging the copper-coated silicon carbide fiber layer on the surface of the copper alloy layer again, and repeating the operation to obtain a composite wire blank in which the copper-coated silicon carbide fiber layers and the copper alloy layers are alternately arranged; and sequentially carrying out hot isostatic pressing treatment, drawing and aging treatment on the composite wire blank to obtain the silicon carbide fiber-copper composite bonding wire. The copper powder further comprises Ag, Hf and Sc, the metal elements can form fine and dispersed second-phase particles in the preparation process, and the strength of the copper bonding wire is remarkably improved through a precipitation strengthening mechanism.

The utility model discloses a high-performance high-temperature-resistant oil-stain-resistant anti-interference medium-voltage power cable, and the power cable comprises a cable core which is formed by twisting a plurality of insulated shielding wire cores. A gap of the cable core is filled with thermoplastic polyurethane elastomer rubber; the cable core is wrapped by a superconducting silicon carbide fiber tape shielding wrapping layer, and the superconducting silicon carbide fiber tape shielding wrapping layer is wrapped by an LCP high-molecular liquid crystal polymer high-temperature-resistant fireproof layer in an extruded mode. A graphene aerogel layer is extruded outside the LCP macromolecular liquid crystal polymer high-temperature-resistant fireproof layer, a polysulfonamide fiber braid layer is lapped outside the graphene aerogel layer, a polyphenylene sulfide fiber tape is coated outside the polysulfonamide fiber braid layer through a semi-conductive adhesive, an armor layer is arranged outside the polyphenylene sulfide fiber tape, and the armor layer is wrapped outside the LCP macromolecular liquid crystal polymer high-temperature-resistant fireproof layer. And a hydrogenated butadiene-acrylonitrile rubber outer sheath is extruded outside the armor layer. According to the utility model, normal operation of a line can be ensured in a complex and severe environment for a long time, and the service life of the cable is greatly prolonged.

The invention provides a high-strength winding thin-wall SiC composite cladding tube and a preparation method thereof. A preparation method of a high-strength winding thin-wall SiC composite cladding tube comprises the steps that silicon carbide fibers are wound and laid around a core mold, the winding pre-tightening force is smaller than or equal to 10 N. The winding mode comprises the first mode that one layer of annular winding is conducted firstly, then one layer of spiral winding is conducted, and the number of fiber intersection points in the whole annular direction at a certain position of the outer surface of the core mold is 1. One-layer annular winding is carried out firstly, then two-layer spiral winding is carried out, the number of fiber intersection points in the whole annular direction at a certain position of the outer surface of the core mold is 3, and a prefabricated body is obtained; carrying out a densification deposition process on the preform, wherein the densification deposition process comprises PyC pyrolytic carbon interface deposition, CVI chemical vapor infiltration and CVD chemical vapor deposition; and precise inner circle and outer circle machining is conducted, and the SiC composite cladding pipe is obtained. According to the preparation method disclosed by the invention, through a specific dry winding mode and a densification deposition process, the SiC composite material tube blank is higher in density and better in mechanical property.

The invention relates to the technical field of thermal insulation materials, in particular to a high-temperature-resistant aerogel composite material and a preparation method thereof. The high-temperature-resistant aerogel composite material is prepared from the following components in parts by weight: 15 to 35 parts of reinforced fiber matrix, 43 to 65 parts of silicon-aluminum-zirconium ternary aerogel network, 3 to 12 parts of functional nano filler, 2 to 8 parts of zinc borate flame-retardant component and 0.5 to 2 parts of surface hydrophobic modified layer. Wherein the reinforced fiber matrix is composed of aluminum silicate fibers, silicon carbide fibers and aluminum oxide nanofibers; the molar ratio of silicon to aluminum to zirconium in the silicon-aluminum-zirconium ternary aerogel network is 5: 2: 1; the functional nanofiller comprises aluminum oxide nanoparticles, titanium oxide nanoparticles, carbon nanotubes and boron nitride nanosheets; the zinc borate flame-retardant component is zinc borate; the surface hydrophobic modification layer comprises an inner methyltrimethoxysilane modification layer and an outer hexamethyldisilazane modification layer. The high temperature resistance and thermal shock resistance of the material are remarkably improved, a low-energy-consumption preparation process is adopted, and the material has excellent comprehensive performance.

The invention discloses a preparation method of a near-stoichiometric aluminum-doped silicon carbide fiber, which comprises the following steps: doping PMS with an aluminum element, blending with PCS, and sequentially carrying out melt spinning, non-melting treatment, high-temperature pyrolysis, high-temperature sintering and the like to obtain the aluminum-doped silicon carbide fiber with a C / Si atomic ratio close to an ideal value. And the near-stoichiometric ratio regulation and control of the silicon carbide fiber components are realized.

The invention relates to a preparation method of a SiC fiber surface rare earth silicate anti-oxidation interface phase. The preparation method comprises the following steps: (1) carrying out pre-oxidation treatment on the surface of the SiC fiber; (2) carrying out hydroxylation on the surface of the pre-oxidized SiC fiber; (3) carrying out alkylation modification on the surface of the hydroxylated SiC fiber; (4) dipping the surface-modified SiC fiber in a precursor solution containing a soluble rare earth source, and heating to obtain the SiC fiber with a rare earth precursor deposited on the surface; and (5) carrying out heat treatment on the SiC fiber with the rare earth precursor deposited on the surface to obtain the SiC fiber surface rare earth silicate anti-oxidation interface phase.

The invention belongs to the technical field of high-performance protective textiles, and particularly relates to a high-temperature-resistant flame-retardant protective fabric and a preparation method thereof.The high-temperature-resistant flame-retardant protective fabric is composed of warp yarn and weft yarn, the warp yarn is formed by ceramic fiber yarn with the diameter of 15-25 micrometers and silicon carbide fiber wound and woven on the surface of the ceramic fiber yarn, and the weft yarn is formed by interweaving the silicon carbide fiber and the ceramic fiber yarn; the diameter of the silicon carbide fibers is 18 microns, the silicon carbide fibers and the ceramic fiber yarns form composite yarns, the weft yarns are blended yarns of aramid fibers and polyphenylene sulfide fibers, the proportion of the aramid fibers to the polyphenylene sulfide fibers is 6: 3: 1, and 5%-10% of flame-retardant viscose fibers are contained. Through composite treatment of the silane coupling agent and the nano silicon dioxide, the interfacial compatibility of the ceramic fiber and the organic fiber is effectively improved, when the fabric is stressed, the stress at the interface can be effectively transmitted, the fabric failure caused by interface debonding is avoided, and the overall mechanical property and durability of the fabric are remarkably enhanced.

The application relates to the field of fireproof bricks, and discloses a baking-free fireproof brick and a preparation method thereof. The baking-free fireproof brick comprises iron tailings, cement, fly ash, a functional additive, fine aggregate, quartz sand, a chromium aluminum phosphate binder, a water reducing agent and water. The functional additive is prepared by using aluminum chloride hexahydrate and alkaline silica sol as raw materials, ammonium molybdate tetrahydrate as a catalyst, growing mullite whiskers on the surface of silicon carbide fibers through vacuum impregnation and heat treatment, modifying the prepared composite silicon carbide fibers through 3-(methacryloxy) propyl trimethoxysilane, and then copolymerizing the modified composite silicon carbide fibers with acrylic acid and 4-hydroxybutyl vinyl ether. The chromium aluminum phosphate binder is prepared by using aluminum hydroxide, phosphoric acid and chromium trioxide as raw materials and calcium hydroxide as a curing agent. The baking-free fireproof brick prepared through the synergistic effect of the components has high compressive strength and bending strength, small water absorption and good baking-free fireproof and heat insulation performance.

The invention relates to a structural wave-absorbing integrated ceramic-based composite material prepared based on 3D printing and a preparation method of the structural wave-absorbing integrated ceramic-based composite material. The preparation method of the structural wave-absorbing integrated ceramic matrix composite material comprises the following steps: mixing chopped silicon carbide fibers, a dispersant, a binder, a catalyst and a solvent to obtain chopped silicon carbide fiber slurry; the slurry is subjected to periodic array arrangement, printing and forming through 3D printing, and a silicon carbide fiber preform of a periodic structure is obtained through drying and glue discharging; inducing in-situ growth of the silicon carbide nanowire on the surface of the preform by using a catalyst introduced into the slurry by adopting CVI, and depositing a BN interface phase on the surface of the silicon carbide nanowire by adopting CVI to form a SiC / BN core-shell structure nanowire; dipping the prefabricated body into a polysilazane precursor, curing and cracking, and introducing a Si3N4 ceramic matrix into the prefabricated body; and repeating dipping, curing and cracking for 5-10 times to densify the composite material, thereby obtaining the structural wave-absorbing integrated ceramic matrix composite material.

The invention relates to the technical field of functional materials, in particular to flexible wave-absorbing silicon carbide fiber cloth and a preparation method thereof. The fiber cloth takes modified silicon carbide fibers as a matrix, graphene nanosheets are uniformly dispersed in the fiber cloth, and the surface of the fiber cloth is coated with a wave-absorbing coating; the wave-absorbing coating comprises the following components in percentage by weight: 30-50% of epoxy resin, 20-35% of carbon nanotubes and the balance of cobalt ferrite nanoparticles; the diameter of the silicon carbide fibers is 5-10 [mu] m, the thickness of the graphene nanosheets is 5-10 nm, the particle size of the cobalt ferrite nanoparticles is 50-100 nm, the pipe diameter of the carbon nanotubes is 10-30 nm, and the length of the carbon nanotubes is 1-10 [mu] m; the silicon carbide fiber cloth prepared by the invention not only has excellent flexibility and mechanical property, but also has excellent wave-absorbing property, and can be widely applied to the fields of stealth clothing, automobile industry, aerospace and the like when being used for preparing stealth composite materials.

The invention discloses a preparation method of SiC fiber / lignite / fly ash high-strength heat storage ceramic, and belongs to the field of heat storage ceramic. The invention aims to solve the problem that the fly ash-based heat storage ceramic with high-strength carbon-based heat-conducting filler cannot be prepared in the prior art. The method comprises the following steps: 1, pyrolyzing lignite powder at high temperature to obtain graphitized lignite powder; 2, mixing the graphitized lignite powder, silicon carbide nanowires, solar salt and fly ash; 3, pressing; and 4, sintering. The method is used for preparing the SiC fiber / lignite / fly ash high-strength heat storage ceramic.

The present invention discloses a boron-containing, high-temperature-resistant, near-stoichiometric silicon carbide fiber and a preparation method thereof. The preparation method includes a spinning stage, an infusibility stage, a pre-sintering stage, a densification sintering stage, and a nitriding stage, and is characterized in that: in the infusibility stage, the metal-doped polycarbosilane precursor fiber obtained in the spinning stage is subjected to a boron-doping reaction in an atmosphere containing boron trichloride and a cross-linking reaction in an atmosphere of a gaseous hydrocarbon having a carbon-carbon double bond. The method is simple to operate, has high production efficiency, low production cost, and is easy to use for large-scale industrial production. The prepared boron-containing, high-temperature-resistant, near-stoichiometric silicon carbide fiber has the advantages of low oxygen content, high degree of densification, few defects, stable structure, high tensile strength modulus, large grain size, and good high-temperature resistance, oxidation resistance, and creep resistance.

The invention provides a SiC / SiC pyrolytic carbon interface optimization method based on a neural network and a phase field fracture method. The SiC / SiC pyrolytic carbon interface optimization method comprises the following steps: firstly, constructing a representative volume element model of a SiC fiber reinforced composite material; performing transverse tensile simulation on the representative volume element model of the SiC fiber reinforced composite material by adopting a phase field fracture method to obtain transverse tensile strength; and finally, screening the optimal interface thickness by taking the transverse tensile strength as a criterion, and training a reverse neural network to realize prediction and optimization of the optimal interface thickness of the SiC fibers with different material parameters. According to the method, an accurate and efficient representative volume element model is used, a phase field fracture method is combined with a reverse design neural network, and the PyC interface parameters are systematically optimized by simulating crack behaviors and predicting the optimal interface thicknesses of fibers with different radiuses, elastic moduli, critical energy release rates and strengths, so that the performance of the PyC interface is improved. Therefore, the mechanical property and the reliability of the SiC / SiC composite material are improved.

A process of producing crystalline SiC fibers comprises dispensing amorphous glass fibers from one or more spools, and continuously moving the amorphous glass fibers through a deoxygenation tube furnace to convert the amorphous glass fibers to porous stoichiometric SiC fibers. The porous stoichiometric SiC fibers are continuously moved out the deoxygenation tube furnace. After exiting the deoxygenation tube furnace, the porous stoichiometric SiC fibers are contacted with a sintering aid to produce doped porous stoichiometric SiC fibers. The continuous process further comprises continuously moving the doped porous stoichiometric SiC fibers through a sintering tube furnace to convert the doped porous stoichiometric SiC fibers to densified stoichiometric crystalline SiC fibers. The densified stoichiometric crystalline SiC fibers are continuously moved out of the sintering tube furnace. Additional methods and stoichiometric crystalline SiC fibers are also disclosed.

The invention discloses a preparation method of an integrally-formed ceramic matrix composite hollow guide vane, the hollow guide vane comprises an upper margin plate, a vane body and a lower margin plate, a hollow guide vane preform is obtained by weaving carbon fibers or silicon carbide fibers, and the fiber interweaving density at the joint of the vane body and the lower margin plate is larger than that at other positions; the method comprises the following steps: preparing a mold based on a hollow guide blade preform, fastening and shaping to obtain a tool, impregnating, cracking and depositing a silicon carbide matrix through a precursor to fill pores among fiber bundles for a certain time, dismounting the tool, and continuously impregnating, cracking and depositing the silicon carbide matrix through the precursor; according to the manufacturing method, continuous and complete fibers at the junctions of the blade body and the upper and lower edge plates are achieved, matrix densification is achieved, the overall strength is effectively improved, the risks of cracking and gas leakage are reduced, tools do not need to be replaced in the manufacturing process, the manufacturing complexity can be greatly reduced, and the manufacturing cost is reduced. The processing period is shortened.

The invention discloses a preparation method of low-cost in-situ doped continuous silicon carbide fiber, which comprises the following steps: by taking vinyl liquid polycarbosilane as a precursor, adding a boron monomer, an organic solvent and metallocene, and doping to prepare a doped polycarbosilane precursor; carrying out melt spinning on the doped precursor to obtain a doped precursor; placing the doped precursor in a mixed gas of an inert atmosphere and a boron-containing active atmosphere, and carrying out thermal crosslinking to obtain a doped crosslinked filament; and finally, pyrolyzing in an ammonia atmosphere to complete partial inorganic transformation of the doped cross-linked wire, then completing inorganic transformation in a hydrogen atmosphere, and finally performing high-temperature heat treatment on the doped cross-linked wire in an inert atmosphere to obtain the in-situ doped continuous silicon carbide fiber. Therefore, the problem of non-uniform coating of a ceramic-based composite material prefabricated body with a complex structure is solved, meanwhile, high cost and large damage to fibers of a secondary coating are avoided, and the composite material preparation technological process is simplified.

The invention relates to the technical field of aluminum alloy composite materials, in particular to a preparation method of a SiC fiber reinforced aluminum matrix composite material. Carrying out hot isostatic pressing treatment on the sheath and the precursor wire, heating the sheath and the precursor wire to 400-500 DEG C at a heating rate of 4-7 DEG C / min, and keeping the temperature and the pressure under the pressure of 80-130 MPa; then cooling to 200 DEG C along with the furnace, maintaining the pressure of 80-130 MPa, and keeping the temperature and pressure; continuously cooling to 100 DEG C along with the furnace, adjusting the pressure to 100 MPa, and keeping the temperature and the pressure; and finally, cooling to room temperature along with the furnace to obtain the SiC fiber reinforced aluminum-based composite material. According to the preparation method, the problems that fibers are broken in advance, interface reaction products are uneven, failure is prone to occurring, and fiber arrangement is uneven in the existing SiC fiber reinforced aluminum matrix composite material preparation process are solved, and the SiC fiber reinforced aluminum matrix composite material with high tensile strength and high compressive strength at room temperature and high compressive strength at 200 DEG C is obtained.