Preparation method of unidirectional continuous fiber toughened ceramic-based composite material

Abstract

The invention provides a preparation method of a unidirectional continuous fiber toughened ceramic-based composite material, and solves the problems that residual air holes exist in fiber bundles and among the fiber bundles and holes and microcracks are easily generated due to long preparation period in the existing preparation method of a continuous carbon fiber toughened silicon carbide ceramic-based composite material; the overall performance of the composite material is poor, the fiber damage is easily caused by high process temperature, and the use temperature of the product can be reduced by residual silicon. Comprising the following steps: depositing a continuous fiber bundle in a pyrolytic carbon or boron nitride deposition furnace to prepare a continuous fiber bundle with an interface layer with a preset thickness; dipping, curing, shaping, pressurizing and curing the continuous fiber bundle with the interface layer with the preset thickness to obtain a continuous one-way composite material fiber preform; and cracking the continuous one-way composite material fiber preform and depositing a SiC matrix to obtain the one-way continuous fiber toughened ceramic matrix composite material with low porosity and low thermal expansion coefficient.

Description

Technical Field

[0001] The present invention relates to a method for preparing a ceramic matrix composite material, and particularly to a method for preparing a unidirectional continuous fiber toughened ceramic matrix composite material. Background Art

[0002] Continuous carbon fiber reinforced silicon ceramic matrix composites (C / SiC) are high-performance materials that combine the lightweight and high-strength characteristics of carbon fibers and the high-temperature stability and wear resistance of silicon carbide. The density of C / SiC composites is only 1 / 3 of that of superalloys, but their strength is twice that of superalloys. They can withstand high temperatures from 1000°C to 1500°C. Moreover, they have better durability, higher fracture toughness and damage tolerance, which makes C / SiC composites an internationally recognized integrated heat protection material and occupy a place in the field of spacecraft.

[0003] Currently, C / SiC composites are usually prepared by chemical vapor infiltration (CVI), polymer impregnation pyrolysis (PIP), and reactive melt infiltration (RMI). Among them, the CVI method is to introduce gases containing silicon and carbon into the fiber preform at high temperature, so that chemical reactions occur on the fiber surface to form a SiC matrix. This method has good matrix densification and excellent oxidation resistance, and is suitable for manufacturing ceramic matrix composites with complex shapes. However, its preparation cycle is long, there are residual pores in the fiber bundle and between the fiber bundles due to the bottleneck effect, and matrix microcracks may be generated during the cooling process, thus affecting the overall performance of the composite material. The PIP method is to impregnate the polymer precursor into the fiber preform and then pyrolyze it at high temperature to convert it into an inorganic ceramic matrix. This method has a lower process temperature and a short cycle, and is suitable for the production of large structural parts. However, holes and microcracks are easily generated in the matrix during the pyrolysis process, resulting in poor overall performance of the composite material. The RMI method is to use liquid silicon to impregnate the solid preform and react with carbon to generate SiC, thereby forming a ceramic matrix. This method has a short preparation cycle, good matrix integrity, and low porosity. However, its process temperature is high, which easily causes fiber damage, and the residual silicon will reduce the service temperature of the product.

[0004] In addition, the above three methods also have the common problems of large thermal expansion coefficient and poor performance consistency of the obtained composite materials. Summary of the Invention

[0005] The object of the present invention is to solve the technical problems of poor overall performance, large thermal expansion coefficient and poor performance consistency of the composite materials prepared by the existing preparation methods of continuous carbon fiber toughened silicon carbide ceramic matrix composite materials, and to provide a preparation method of unidirectional continuous fiber toughened ceramic matrix composite materials.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A preparation method of unidirectional continuous fiber toughened ceramic matrix composite materials is characterized by comprising the following steps:

[0008] Step 1, preparing an interface layer

[0009] Select a continuous fiber bundle and wind it around a mold, and then place it in a pyrolytic carbon or boron nitride deposition furnace for deposition until a continuous fiber bundle with a preset thickness interface layer is obtained;

[0010] Step 2, impregnation, curing and shaping treatment

[0011] Step 2.1, wind the continuous fiber bundle around a fiber unwinding reel, and pass one end of it through a precursor impregnation tank and a shaping and curing unit in sequence, and then wind it around a fiber winding device;

[0012] Step 2.2, add a first ceramic precursor to the precursor impregnation tank, set the temperature of the shaping and curing unit, and then start the fiber winding device to make the continuous carbon fiber bundle impregnate in the first ceramic precursor and be cured by the shaping and curing unit in sequence, and then wind it around the fiber winding device;

[0013] Step 2.3, take down the fiber wound on the fiber winding device and cut it to the required length, place the cut fiber into the precursor impregnation tank, impregnate it with a second ceramic precursor, take out the fiber and place it in a unidirectional composite material preparation mold for curing, and set the curing pressure and curing temperature at the same time to obtain a continuous unidirectional composite material fiber preform;

[0014] Step 3, PIOP and CVI treatment

[0015] Put the continuous unidirectional composite material fiber preform into a chemical vapor deposition furnace for pyrolysis and deposition of a SiC matrix to obtain a unidirectional continuous fiber toughened ceramic matrix composite material with low porosity and low thermal expansion coefficient.

[0016] Further, step 1 is specifically:

[0017] Select continuous carbon fiber bundles and wind them around a graphite mold, then place them in a pyrolytic carbon or boron nitride deposition furnace. At a deposition temperature of 880 - 920 °C and a deposition pressure of 4 - 6 KPa, introduce the precursor gas source C3H6 for deposition until continuous carbon fiber bundles with a pyrolytic carbon interface layer of 200 - 250 nm thickness are obtained. Then, heat-treat them under vacuum conditions at 1750 - 1850 °C for 1.5 - 2.5 h to obtain continuous fiber bundles with an interface layer of a preset thickness; the thickness range of the continuous carbon fiber bundles is 1 - 12K.

[0018] Further, in step 2.1, a U-shaped guide wheel group and a V-shaped guide wheel group are also provided;

[0019] The U-shaped guide wheel group is rotatably connected between the fiber unwinding reel and the precursor impregnation tank through a bracket, and is used to guide the movement of the continuous carbon fiber bundles on the fiber unwinding reel;

[0020] The V-shaped guide wheel group is rotatably connected between the precursor impregnation tank and the shaping and curing unit through a bracket, and is used to guide the movement of the continuous carbon fiber bundles passing through the precursor impregnation tank;

[0021] The fiber winder includes a motor, a winding disc connected to the driving end of the motor, and a plurality of winding shafts evenly distributed on the surface of the winding disc along the circumference.

[0022] Further, step 2.2 is specifically as follows:

[0023] Add the first ceramic precursor to the precursor impregnation tank and set the temperature of the shaping and curing unit;

[0024] Make the continuous carbon fiber bundles pass through the U-shaped guide wheel group, be impregnated with the first ceramic precursor, pass through the V-shaped guide wheel group, be cured by the shaping and curing unit, and then be wound around the winding shafts of the fiber winder;

[0025] Start the motor of the fiber winder. The motor drives the winding shafts on the winding disc to rotate, so that the continuous carbon fiber bundles are successively unfolded and impregnated in the first ceramic precursor through the U-shaped guide wheel group, gathered by the V-shaped guide wheel group, cured by the shaping and curing unit, and then wound around the winding shafts.

[0026] Further, step 2.2 is specifically as follows:

[0027] Add the first ceramic precursor to the precursor impregnation tank and set the temperature of the shaping and curing unit to 150 - 300 °C, and the curing time is not less than 40 s;

[0028] Start the motor of the fiber winder. The motor drives the winding shaft on the take-up reel to rotate, so that the continuous carbon fiber bundle is successively unfolded and impregnated in the first ceramic precursor through the U-shaped guide wheel set, gathered by the V-shaped guide wheel set, solidified by the shaping and solidifying unit, and then wound on the winding shaft. The winding speed of the winding shaft is <0.5 cm / s.

[0029] Furthermore, the shaping and solidifying unit includes a heating table and a solidifying and shaping device;

[0030] The solidifying and shaping device is connected to the heating table; a shaping groove is opened in the middle of the solidifying and shaping device. The shaping groove is used for threading the continuous fiber bundle, and the continuous fiber bundle in the shaping groove is heated, shaped, and solidified through the solidifying and shaping device;

[0031] The heating table is used to heat the solidifying and shaping device, and further heat the continuous fiber bundle in the shaping groove.

[0032] Furthermore, in step 2, both the first ceramic precursor and the second ceramic precursor are polycarbosilane PCS or hyperbranched polycarbosilane AHPCS.

[0033] Furthermore, in step 2, the impregnation time in the first ceramic precursor and the second ceramic precursor is not less than 40 s.

[0034] Furthermore, in step 2.3, the unidirectional composite material preparation mold includes a cuboid base and a cuboid cover plate;

[0035] x cuboid grooves are equally spaced on the cuboid base, where x≥1; the cuboid grooves are used to place the fibers impregnated with the second ceramic precursor;

[0036] x cuboid bosses are integrally connected to the cuboid cover plate. Each cuboid boss fits and actively extends into a cuboid groove, and the cuboid boss is used to press the fibers in the cuboid groove;

[0037] When the cuboid cover plate is connected to the cuboid groove of the cuboid base, the minimum distance from the bottom surface of the cuboid groove is 4 mm to 5 mm, and the width of the cuboid groove is 4 mm to 7 mm.

[0038] Furthermore, in step 2.3, set the solidifying pressure to apply a downward pressure on the cuboid cover plate. The applied pressure range is: 10x N to 90x N, and the pressurization time is not less than 45 s;

[0039] The set solidifying temperature is specifically: take out the fiber and place it in the unidirectional composite material preparation mold, heat the unidirectional composite material preparation mold or place the unidirectional composite material preparation mold in a high-temperature furnace for heating. The heating temperature is 150 - 300 °C, and the heating time is not less than 45 s.

[0040] Further, step 3 is specifically as follows: placing the continuous unidirectional composite material fiber preform into a SiC deposition furnace, heating it in the furnace to 950 - 1050 °C for pyrolysis and deposition of the SiC matrix until the density is greater than 2.0 g / cm 3 , stopping the deposition, and cooling it to room temperature to obtain a unidirectional continuous fiber toughened ceramic matrix composite material with low porosity and low thermal expansion coefficient.

[0041] Advantages of the present invention:

[0042] 1. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material provided by the present invention has a short preparation period, can improve production efficiency, and the obtained unidirectional continuous fiber toughened ceramic matrix composite material has the advantages of low porosity, low thermal expansion coefficient, good performance consistency, and good overall performance.

[0043] 2. In the present invention, a unidirectional composite material preparation mold is adopted, and the fiber material is pressurized and heated through the mold, thereby reducing the porosity of the material and also reducing the cracks inside the unidirectional continuous fiber toughened ceramic matrix composite material.

[0044] 3. In the present invention, the provided U-shaped guide wheel group can further improve the infiltration effect of the continuous carbon fiber bundle, the provided take-up shaft can reduce the bending of the prestressed fiber, and in addition, the take-up speed of the take-up shaft < 0.5 cm / s can ensure sufficient infiltration of the fiber. Description of the drawings

[0045] Figure 1 is a flowchart of the preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material of the present invention;

[0046] Figure 2 is a schematic diagram of the positional relationship among the precursor impregnation tank, the shaping and curing unit, the U-shaped guide wheel group, the V-shaped guide wheel group, and the fiber winder used in the first embodiment of the present invention;

[0047] Figure 3 is a schematic diagram of the structure of the shaping and curing unit in the first embodiment of the present invention;

[0048] Figure 4 is a schematic diagram of the structure of the unidirectional composite material preparation mold in the first embodiment of the present invention;

[0049] Figure 5Schematic cross-sectional view of 1D unidirectional continuous fiber toughened ceramic matrix composites with different fiber volume fractions prepared in the embodiments of the present invention. Among them, (a) is the schematic cross-sectional view of the unidirectional continuous fiber toughened ceramic matrix composite with a fiber volume fraction of 19%, (b) is the schematic cross-sectional view of the unidirectional continuous fiber toughened ceramic matrix composite with a fiber volume fraction of 25%, (c) is the schematic cross-sectional view of the unidirectional continuous fiber toughened ceramic matrix composite with a fiber volume fraction of 31%, and (d) is the schematic cross-sectional view of the unidirectional continuous fiber toughened ceramic matrix composite with a fiber volume fraction of 37%.

[0050] Figure 6 Schematic diagram of the test results of the axial thermal expansion performance of unidirectional continuous fiber toughened ceramic matrix composites with different fiber volume fractions in the embodiments of the present invention. Among them, (a) is the schematic diagram of the linear expansion amount changing with temperature, and (b) is the schematic diagram of the thermal expansion coefficient changing with temperature.

[0051] Explanation of reference numerals:

[0052] 1 - Precursor impregnation tank, 2 - Shaping and curing unit, 3 - Fiber winder, 4 - U-shaped guide wheel group, 5 - V-shaped guide wheel group, 6 - Cuboid base, 7 - Cuboid cover plate. Detailed implementation manners

[0053] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0054] Embodiment 1

[0055] As Figure 1 shown, a method for preparing a unidirectional continuous fiber toughened ceramic matrix composite includes the following steps:

[0056] Step 1, preparing an interface layer

[0057] Select a continuous carbon fiber bundle of 3K T300 and wind it around a graphite mold, then place it in a pyrolytic carbon deposition furnace. At a deposition temperature of 900°C, a deposition pressure of 5 KPa, and introducing a precursor gas source C3H6 for deposition until a continuous carbon fiber bundle with a pyrolytic carbon interface layer of 230 nm thickness is obtained. The reaction equation is shown in (1-1). Then, heat treatment is carried out under vacuum conditions at 1800°C for 2 h to improve the crystallization degree of the pyrolytic carbon interface layer, and a continuous fiber bundle with a preset thickness interface layer is obtained.

[0058] C3H6(g) → 3C(s) + 3H2 (g) (1-1)

[0059] Step 2: Impregnation, curing and shaping treatment

[0060] Step 2.1: Wind the continuous fiber bundle around the fiber unwinding reel as Figure 2 shown, and pass one end of it through the U-shaped guide wheel set 4, the precursor impregnation tank 1, the V-shaped guide wheel set 5, and the shaping and curing unit 2 in sequence, and then wind it around the fiber winding device 3. The U-shaped guide wheel set 4 includes a first U-shaped guide wheel outside the precursor impregnation tank 1 and a second U-shaped guide wheel inside the precursor impregnation tank 2. A V-shaped guide wheel set 5 is arranged between the precursor impregnation tank 1 and the curing unit 2. The V-shaped guide wheel set 5 includes a first V-shaped guide wheel inside the precursor impregnation tank 1 and a second V-shaped guide wheel outside the precursor impregnation tank 1. The fiber winding device 3 includes a motor, a wire winding disc connected to the driving end of the motor, and eight wire winding shafts with a diameter of 30 cm evenly distributed on the surface of the wire winding disc along the circumference.

[0061] Among them, the structure of the shaping and curing unit 2 is as Figure 3 shown, and it includes a heating table and a shaping and curing device;

[0062] The shaping and curing device is connected to the heating table; a shaping groove is opened in the middle of the shaping and curing device. The shaping groove is used to penetrate the continuous fiber bundle, and the continuous fiber bundle in the shaping groove is heated, shaped and cured through the shaping and curing device;

[0063] The heating table is used to heat the shaping and curing device, and then heat the continuous fiber bundle in the shaping groove.

[0064] In this embodiment, the shaping and curing unit 2 is used to accurately control the curing temperature, and the motor of the fiber winding device 3 is used to control the fiber winding speed and provide power.

[0065] Step 2.2: Add polycarbosilane PCS into the precursor impregnation tank 1, set the temperature of the curing unit 2 to 150 °C, and then start the fiber winding device 3. After the continuous carbon fiber bundle is impregnated in polycarbosilane PCS for 45 s and cured by the shaping and curing unit 2, the temperature of the curing unit 2 is 150 °C, the curing time is 1 min, and it is wound around the fiber winding device 3.

[0066] Step 2.3: Take off the fiber wound on the fiber winding device 3 and cut it according to the required length to obtain 30 3k carbon fiber bundles. Place the 30 3k carbon fiber bundles into the precursor impregnation tank 1, add polycarbosilane PCS and impregnate for 50 s, then take out the fiber and place it in a unidirectional composite material preparation mold for curing. At the same time, set the curing pressure to 60 N and the curing temperature to 180 °C. The setting time of the curing pressure and the curing temperature is both 1 min to obtain a continuous unidirectional composite material fiber preform. The wire winding speed of the wire winding shaft is 0.45 cm / s.

[0067] Among them, the reaction mechanism of curing is mainly hydrosilylation, dehydrogenation coupling and double bond self-polymerization reaction, which are respectively expressed as formula (1-2), (1-3) and (1-4), as follows:

[0068] ≡Si-CH=CH2+H-Si≡→≡Si-CH2CH2-Si≡ (1-2)

[0069] ≡Si-H+H-Si≡→≡Si-Si≡+H2 (1-3)

[0070] 2≡Si-CH=CH2→≡Si-CH-CH2-CH2-CH-Si≡ (1-4)

[0071] 丨丨.

[0072] In this embodiment, Figure 4 As shown, the unidirectional composite material preparation mold includes a rectangular base 6 and a rectangular cover plate 7;

[0073] Five rectangular grooves are provided at equal intervals on the rectangular base 6, wherein the rectangular grooves are used to place fibers impregnated with polycarbosilane PCS;

[0074] The rectangular cover plate 7 is integrally connected with five rectangular bosses, each of which fits and actively extends into a rectangular groove, and the rectangular boss is used to pressurize the fibers in the rectangular groove;

[0075] When the rectangular cover plate 7 is connected to the rectangular groove of the rectangular base 6, the minimum distance from the bottom surface of the rectangular groove is 4 mm, and the width of the rectangular groove is 5 mm.

[0076] Step 3: PIOP and CVI processing

[0077] The continuous unidirectional composite fiber preform was placed in a SiC deposition furnace. When the furnace temperature was raised to 1000°C, the SiC matrix was pyrolyzed and deposited for 2 hours. Then, the temperature was lowered to room temperature to obtain a density greater than 2.0 g / cm 3 The unidirectional continuous fiber-reinforced ceramic matrix composite material with low porosity and low thermal expansion coefficient, the fiber volume fraction in the unidirectional continuous fiber-reinforced ceramic matrix composite material obtained in this embodiment is 19%.

[0078] Embodiment 2

[0079] Step 1: Preparation of pyrolytic carbon interface layer

[0080] Select continuous carbon fiber bundles and wind them around a graphite mold, then place it in a pyrolytic carbon or boron nitride deposition furnace. At a deposition temperature of 900 °C and a deposition pressure of 5 KPa, introduce a precursor gas source for deposition until a continuous carbon fiber bundle with a pyrolytic carbon interface layer of 220 nm thickness is obtained. Then, heat-treat it under vacuum conditions at 1800 °C for 2 h to obtain a continuous fiber bundle with an interface layer of a preset thickness; the thickness range of the continuous carbon fiber bundle is 9K.

[0081] Step 2.1 and Step 2.2 in Step 2 are the same as Step 2.1 and Step 2.2 in Example 1.

[0082] Step 2.3: Remove the fibers wound on the fiber winder 3 and cut them to the required length to obtain 40 3k carbon fiber bundles. Place the 40 3k carbon fiber bundles into the precursor impregnation tank 1, add polycarbosilane PCS for impregnation, then take out the fibers and place them in a unidirectional composite material preparation mold for curing. At the same time, set the curing pressure to 150 N and the curing temperature to 250 °C to obtain a continuous unidirectional composite material fiber preform.

[0083] Step 3: PIOP and CVI treatment

[0084] Put the continuous unidirectional composite material fiber preform into a SiC deposition furnace, heat it up to 1000 °C with the furnace and pyrolyze and deposit the SiC matrix until the density reaches 2.1 g / cm 3 , stop deposition, cool down to room temperature to obtain a unidirectional continuous fiber toughened ceramic matrix composite with low porosity and low coefficient of thermal expansion. The fiber volume fraction in the unidirectional continuous fiber toughened ceramic matrix composite obtained in this example is 25%.

[0085] Example 3

[0086] The difference between this example and Example 1 is that the first ceramic precursor is polycarbosilane PCS, and the second ceramic precursor is hyperbranched polycarbosilane AHPCS.

[0087] In Step 2.3, remove the fibers wound on the fiber winder 3 and cut them to the required length to obtain 50 3k carbon fiber bundles. Place the 50 3k carbon fiber bundles into the precursor impregnation tank 1, add polycarbosilane PCS for impregnation, then take out the fibers and place them in a unidirectional composite material preparation mold for curing. At the same time, set the curing pressure to 220 N and the curing temperature to 260 °C to obtain a continuous unidirectional composite material fiber preform. The fiber volume fraction in the unidirectional continuous fiber toughened ceramic matrix composite obtained in this example is 31%.

[0088] Example 4

[0089] The difference between this embodiment and Embodiment 3 is that the fibers wound on the fiber winder 3 are taken off and cut to the required length to obtain 60 3k carbon fiber bundles. The 60 3k carbon fiber bundles are placed in the precursor impregnation tank 1, impregnated with polycarbosilane (PCS), then the fibers are taken out and placed in a unidirectional composite material preparation mold for curing. Meanwhile, the curing pressure is set to 340 N and the curing temperature is set to 280 °C to obtain a continuous unidirectional composite material fiber preform. The fiber volume fraction in the unidirectional continuous fiber toughened ceramic matrix composite material obtained in this embodiment is 37%.

[0090] Figure 5 1D C / SiC bending specimens with different fiber volume percentages are prepared by using Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 of the present invention. 30, 40, 50 and 60 3k carbon fiber bundles are respectively pressed into 1D continuous unidirectional composite material fiber preforms with a cross-sectional area of 5×4 mm, and 1D unidirectional continuous fiber toughened ceramic matrix composite materials with fiber volume fractions of 19%, 25%, 31% and 37% are obtained by using the CVI+PIOP method. Their cross-sectional areas are as Figure 5 shown Figure 5 In the figure, (a) is the cross-section of the unidirectional continuous fiber toughened ceramic matrix composite material with a fiber volume fraction of 19%, (b) is the cross-section of the unidirectional continuous fiber toughened ceramic matrix composite material with a fiber volume fraction of 25%, (c) is the cross-section of the unidirectional continuous fiber toughened ceramic matrix composite material with a fiber volume fraction of 31%, and (d) is the cross-section of the unidirectional continuous fiber toughened ceramic matrix composite material with a fiber volume fraction of 37%.

[0091] According to Figure 5 it can be seen that 1D C / SiC with different fiber volume fractions has achieved a relatively good densification effect after two densification processes, no obvious void distribution is observed, and the fibers are evenly distributed. Thus, it can be known that the preparation method of the unidirectional continuous fiber toughened ceramic matrix composite material of the present invention reduces the porosity of the material. In addition, as the fiber volume fraction increases, the fiber tows tend to contact each other, and the reduction of the matrix phase between the fibers will surely affect its mechanical properties.

[0092] The axial thermal expansion properties of the unidirectional continuous fiber toughened ceramic matrix composite materials with different fiber volume fractions are tested, as Figure 6 shown, where (a) is the schematic diagram of the linear expansion amount changing with temperature, and (b) is the schematic diagram of the thermal expansion coefficient changing with temperature; According to Figure 6It can be seen that with the increase of the fiber volume percentage, both its thermal expansion amount and thermal expansion coefficient decrease. The reason for this phenomenon is that in the unidirectional continuous fiber toughened ceramic matrix composite, the presence of fibers has a constraining effect on the thermal expansion of the matrix material. Therefore, with the increase of the fiber volume percentage, the contact area between the fibers and the matrix increases, and this constraining effect increases, so the thermal expansion of SiC will be restricted. In addition, according to the thermal expansion mixing rule formula (1-4) of the unidirectional composite material, the thermal expansion of the composite material is the weighted average of the properties of its components. Since the thermal expansion coefficient of the fiber is lower than that of the SiC matrix, the overall thermal expansion coefficient of the unidirectional continuous fiber toughened ceramic matrix composite will decrease with the increase of the fiber content.

[0093] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material, characterized in that, It includes the following steps: Step 1: Prepare the interface layer Select a continuous fiber bundle and wind it around a mold, and then place it in a pyrolytic carbon or boron nitride deposition furnace for deposition until a continuous fiber bundle with an interface layer of a preset thickness is obtained; Step 2: Impregnation, curing and shaping treatment Step 2.1: Wind the continuous fiber bundle obtained in Step 1 around a fiber unwinding reel, and pass one end of it through a precursor impregnation tank (1) and a shaping and curing unit (2) in sequence, and then wind it around a fiber winding device (3); Step 2.2: Add a first ceramic precursor to the precursor impregnation tank (1), set the temperature of the shaping and curing unit (2), and then start the fiber winding device (3) to make the continuous carbon fiber bundle impregnate in the first ceramic precursor and be cured by the shaping and curing unit (2) in sequence, and then wind it around the fiber winding device (3); Step 2.3: Take down the fiber wound on the fiber winding device (3) and cut it to the required length, place the cut fiber in another precursor impregnation tank (1), impregnate it with a second ceramic precursor, take out the fiber and place it in a unidirectional composite material preparation mold for curing, and set the curing pressure and curing temperature at the same time to obtain a continuous unidirectional composite material fiber preform; Step 3: PIOP and CVI treatment Put the continuous unidirectional composite material fiber preform into a chemical vapor deposition furnace for pyrolysis and deposition of a SiC matrix to obtain a unidirectional continuous fiber toughened ceramic matrix composite material with a low porosity and a low coefficient of thermal expansion.

2. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 1, wherein, Specifically, Step 1 is as follows: Select a continuous carbon fiber bundle and wind it around a graphite mold, and then place it in a pyrolytic carbon or boron nitride deposition furnace. At a deposition temperature of 880-920 °C and a deposition pressure of 4-6 KPa, introduce a precursor gas source for deposition until a continuous carbon fiber bundle with a pyrolytic carbon interface layer with a thickness of 200-250 nm is obtained, and then perform heat treatment in a vacuum condition at 1750-1850 °C for 1.5-2.5 h to obtain a continuous fiber bundle with an interface layer of a preset thickness; the thickness range of the continuous carbon fiber bundle is 1-12K.

3. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 1, characterized in that: In Step 2.1, a U-shaped guide wheel group (4) and a V-shaped guide wheel group (5) are also provided; The U-shaped guide wheel group (4) is rotatably connected between the fiber unwinding reel and the precursor impregnation tank (1) through a bracket, and is used to guide the movement of the continuous fiber bundle on the fiber unwinding reel; The V-shaped guide wheel group (5) is rotatably connected between the precursor impregnation tank (1) and the shaping and curing unit (2) through a bracket, and is used to guide the movement of the continuous fiber bundle passing through the precursor impregnation tank (1); The fiber winding device (3) includes a motor, a wire winding disc connected to the driving end of the motor, and a plurality of wire winding shafts evenly distributed on the surface of the wire winding disc along the circumference.

4. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite according to claim 3, characterized in that, Specifically, Step 2.2 is as follows: Add a first ceramic precursor to the precursor impregnation tank (1), set the temperature of the shaping and curing unit (2) to 150-300 °C, and the curing time is not less than 40 s; Then start the motor of the fiber winder (3). The motor drives the winding shaft on the winding disk to rotate, so that the continuous carbon fiber bundle is successively impregnated in the first ceramic precursor through the U-shaped guide pulley group (4), bundled by the V-shaped guide pulley group (5), solidified by the shaping and solidifying unit (2), and then wound on the winding shaft. The winding speed of the winding shaft is <0.5 cm / s.

5. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 4, characterized in that: The shaping and solidifying unit (2) includes a heating table and a solidifying and shaping device; The solidifying and shaping device is connected to the heating table; a shaping groove is provided in the middle of the solidifying and shaping device. The shaping groove is used for passing through the continuous fiber bundle, and the continuous fiber bundle in the shaping groove is heated, shaped and solidified by the solidifying and shaping device; The heating table is used to heat the solidifying and shaping device, and further heat the continuous fiber bundle in the shaping groove.

6. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite according to claim 1, characterized in that: In step 2, the first ceramic precursor and the second ceramic precursor are both polycarbosilane PCS or hyperbranched polycarbosilane AHPCS.

7. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite according to claim 1, characterized in that: In step 2.2, the impregnation time in the first ceramic precursor and in step 2.3, the impregnation time in the second ceramic precursor are both not less than 40 s.

8. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 1, characterized in that: In step 2.3, the unidirectional composite material preparation mold includes a cuboid base (6) and a cuboid cover plate (7); x cuboid grooves are equidistantly arranged on the cuboid base (6), where x≥1; the cuboid grooves are used for placing the fiber impregnated with the second ceramic precursor; x cuboid bosses are integrally connected to the cuboid cover plate (7). Each cuboid boss fits and actively extends into a cuboid groove, and the cuboid boss is used to press the fiber in the cuboid groove; When the cuboid cover plate (7) is connected to the cuboid groove of the cuboid base (6), the minimum distance from the bottom surface of the cuboid groove is 4 mm to 5 mm, and the width of the cuboid groove is 4 mm to 7 mm.

9. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 8, characterized in that: In step 2.3, the solidifying pressure is set to apply a downward pressure on the cuboid cover plate, and the applied pressure range is: 10x N to 90x N, and the pressurization time is not less than 45 s; The specific solidifying temperature is: take out the fiber and place it in the unidirectional composite material preparation mold, heat the unidirectional composite material preparation mold or place the unidirectional composite material preparation mold in a high-temperature furnace for heating. The heating temperature is 150 to 300 °C, and the heating time is not less than 45 s.

10. The preparation method of a unidirectional continuous fiber toughened ceramic matrix composite material according to claim 1, characterized in that, Step 3 specifically is: Put the continuous unidirectional composite material fiber preform into the SiC deposition furnace, heat it up in the furnace to 950 - 1050 °C for pyrolysis and deposition of the SiC matrix until the density is greater than 2.0 g / cm 3 , stop deposition, cool it down to room temperature to obtain the unidirectional continuous fiber toughened ceramic matrix composite material with low porosity and low thermal expansion coefficient.

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