Shaping mold of ceramic matrix composite hollow hexahedron component prefabricated body and preparation method of hollow hexahedron component

Abstract

The invention provides a shaping mold of a ceramic matrix composite hollow hexahedron component prefabricated body and a preparation method of a hollow hexahedron component, and can solve the problems that when an existing mold is adopted for shaping, the hollow hexahedron component prefabricated body is prone to cracks, the clamping force of the mold is not uniform, and the fitting rate of the mold and fiber cloth is low, so that a product is layered, pores are formed, and the product quality is poor. The mechanical property of the product is influenced. The shaping mold comprises an inner mold assembly, an outer mold assembly and a fastening assembly, the inner mold assembly comprises a left inner mold, a right inner mold, an inner mold adjusting plate, a windowing front panel and a first positioning pin, the left inner mold comprises an upper frame, a right frame, a lower frame and a left frame which are sequentially closed to form a rectangular frame structure and a windowing rear panel arranged on the rear side of the rectangular frame structure, and the right inner mold and the left inner mold are the same in structure; the windowing front panel is buckled on the front side of the rectangular frame structure, the outer mold assembly is arranged on the outer side of the inner mold assembly and comprises a front cover plate, an upper outer mold and a lower outer mold, the upper outer mold and the lower outer mold are buckled into a rectangular frame with a rear cover plate, and the front cover plate is buckled on the front side face of the rectangular frame.

Description

Technical Field

[0001] The invention relates to a shaping die for a ceramic-based composite material component preform and a method for preparing the component, and in particular to a shaping die for a ceramic-based composite material hollow hexahedral component preform and a method for preparing the hollow hexahedral component. Background Art

[0002] The shaping of the ceramic matrix composite component preform is mainly achieved by laying multiple layers of carbon fiber cloth or silicon carbide fiber cloth on the predetermined rigid surface of the graphite shaping mold and performing the mold closing operation. However, in the shaping process of the hollow hexahedral component preform, due to the difference in thermal expansion coefficients between the existing hollow hexahedral graphite shaping mold and the hollow hexahedral component preform, it is easy to cause cracks in the hollow hexahedral component preform during subsequent high-temperature treatment. In addition, due to the complex curved surface characteristics of the hollow hexahedral component preform, the holding force of the graphite shaping mold is often uneven and the bonding rate with the fiber cloth is low, which leads to uneven deposition of the subsequent interface layer and the matrix layer. The final hollow hexahedral component product has defects such as stratification and pores, which affects the mechanical properties of the product. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problem that when the existing hollow hexahedral graphite shaping mold is used for shaping, the hollow hexahedral component preform is prone to cracks, the holding force of the graphite shaping mold is uneven, and the bonding rate with the fiber cloth is low, resulting in defects such as stratification and porosity in the hollow hexahedral component product, which affects the mechanical properties of the product. A shaping mold for a hollow hexahedral component preform of a ceramic-based composite material and a method for preparing a hollow hexahedral component are provided.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A shaping mold for a preform of a hollow hexahedral component of a ceramic matrix composite material, which is special in that:

[0006] It includes an inner mold component, an outer mold component, and a fastening component for pressing the outer mold component;

[0007] The inner mold assembly comprises a left inner mold, a right inner mold, an inner mold adjustment plate, two window front panels and at least two first positioning pins; the left inner mold comprises an upper frame, a right frame, a lower frame, and a left frame which are closed in sequence to form a rectangular frame structure, and a window rear panel arranged on the rear side of the rectangular frame structure; the right frame of the left inner mold is provided with at least two first positioning holes; the right inner mold has the same structure as the left inner mold, and the left frame of the right inner mold is provided with at least two second positioning holes; the first positioning pin can pass through the first positioning hole, the inner mold adjustment plate and the second positioning hole in sequence; the two window front panels are respectively buckled on the front sides of the left inner mold rectangular frame structure and the right inner mold rectangular frame structure; the height of the inner mold adjustment plate in the up-down direction is less than the height of the two window front panels close to the window edge in the up-down direction, and the width of the inner mold adjustment plate in the front-to-back direction is less than the distance between the window front panel and the window rear panel;

[0008] The inner mold component is provided with sewing holes on its use profile;

[0009] The outer mold assembly is arranged outside the inner mold assembly, and the use profile of the outer mold assembly is adapted to the use profile of the inner mold assembly; the outer mold assembly includes an upper outer mold, a lower outer mold, and a front cover plate; the upper outer mold and the lower outer mold are symmetrical structures, and are combined into a rectangular frame with a rear cover plate through a plurality of connecting ear buckles; the front cover plate is buckled on the front side of the rectangular frame; the front cover plate and the rear cover plate are both window structures;

[0010] The front cover plate, the window front panel, the window rear panel and the rear cover plate are arranged in sequence from front to back.

[0011] Furthermore, the use profile of the inner mold assembly is a profile of uniform wall thickness along the thickness direction, and its wall thickness is 5-10 mm;

[0012] The use profile of the outer mold component is a profile with a constant wall thickness in the thickness direction, and its wall thickness is 8-12mm;

[0013] The wall thickness of the inner mold adjustment plate is 1-5 mm.

[0014] Furthermore, the left frame and the lower frame of the left inner mold and the lower frame and the right frame of the right inner mold are provided with a plurality of breaking grooves;

[0015] The diameter of the sewing holes is 1.5-10 mm, and the distance between the centers of adjacent sewing holes is 1-15 mm.

[0016] Furthermore, the fastening assembly includes a plurality of reinforcement frames and wedge blocks; the reinforcement frames are sleeved outside the outer mold assembly, and the wedge blocks are arranged between the reinforcement frames and the outer mold assembly to press the outer mold assembly in the front-rear direction;

[0017] A first detection reference hole is arranged on the window rear panel; a second detection reference hole corresponding to the first detection reference hole is arranged on the window front panel, the rear cover plate and the front cover plate, and the first detection reference hole and the second detection reference hole are used for factory re-inspection.

[0018] Furthermore, a plurality of reinforcing ribs are provided on the front side surface of the front cover plate and the rear side surface of the rear cover plate;

[0019] The shape of the destruction groove is rectangular, square, circular or irregular;

[0020] The material of the inner mold adjustment plate is a ceramic-based composite material;

[0021] The materials of the inner mold component, the outer mold component and the fastening component are high-temperature materials; the high-temperature materials are high-strength fine graphite, high-purity graphite or electrode graphite.

[0022] At the same time, the present invention also provides a method for preparing a hollow hexahedral component of a ceramic-based composite material, which is based on the shaping mold of the preform of the hollow hexahedral component of the ceramic-based composite material, and is special in that it includes the following steps:

[0023] 1) Assemble the inner mold components

[0024] 1.1) Glue the left inner mold to one of the front panels with windows, and glue the right inner mold to the other front panel with windows;

[0025] 1.2) Using the first positioning pin, the left inner mold, the inner mold adjustment plate and the right inner mold are positioned and connected and glued to form an inner mold assembly;

[0026] 2) Prefabricated hollow hexahedron components

[0027] 2.1) Calculate the amount of fiber cloth required for the hollow hexahedral component preform and cut it;

[0028] 2.2) Laying and flanging the cut fiber cloth layer by layer on the service surface of the inner mold component to obtain a hollow hexahedral component preform intermediate;

[0029] 2.3) The hollow hexahedral component preform intermediate body and the rectangular frame and front cover formed by buckling the upper outer mold and the lower outer mold are tested for mold fitting. After the test mold fitting meets the requirements, the rectangular frame and the front cover are removed, and then sewing and locking are performed to obtain the hollow hexahedral component preform;

[0030] 2.4) The hollow hexahedral component preform and the rectangular frame formed by buckling the upper outer mold and the lower outer mold are molded together, and then the front cover plate is buckled on the front side of the rectangular frame, and finally the outer mold assembly is fastened with a fastening assembly;

[0031] 3) Preparation of interface layer and high temperature treatment

[0032] The interface layer of the hollow hexahedral component preform fastened in step 2.4) is prepared by chemical vapor deposition, and then the inner mold adjustment plate is removed, and then high temperature treatment is performed;

[0033] 4) preparing a silicon carbide substrate layer;

[0034] The hollow hexahedral component preform treated in step 3) is subjected to a chemical vapor deposition method to prepare a silicon carbide matrix layer, and demolding is performed during the process;

[0035] 5) Machining

[0036] The hollow hexahedral component preform on which the silicon carbide matrix layer is prepared is subjected to mechanical processing and subsequent treatment to obtain a hollow hexahedral component of a ceramic-based composite material.

[0037] Further, step 4) specifically includes the following steps:

[0038] 4.1) placing the hollow hexahedral component preform processed in step 3) in a deposition furnace, and setting the pressure in the furnace to 200-5000 Pa;

[0039] 4.2) Raise the temperature to 900-1200°C, keep warm for 1-2 hours, then introduce a mixed gas of trichloromethylsilane, hydrogen and argon, the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-20:10-30, deposit for 30-80 hours, keep warm for 2 hours, and then cool to room temperature;

[0040] 4.3) After repeating step 4.2) two to four times, take out the hollow hexahedral component preform with the silicon carbide matrix layer, and remove the inner mold assembly by knocking the inner mold assembly;

[0041] 4.4) The hollow hexahedral component preform with the inner mold assembly removed in step 4.3) is placed in a deposition furnace with a furnace pressure of 200-5000 Pa, and cyclic deposition is performed according to the process of step 4.2) until the density of the silicon carbide substrate layer is 1.75-1.8 g / cm 3 , remove the outer mold components.

[0042] Further, step 2.3) specifically includes the following steps:

[0043] 2.3.1) Test mold the hollow hexahedral component preform intermediate body and the rectangular frame formed by buckling the upper outer mold and the lower outer mold;

[0044] 2.3.2) Use a 0.15mm feeler gauge to detect the gap between the hollow hexahedral component preform intermediate and the rectangular frame use mold surface. If the gap is ≥0.15mm, proceed to step 2.3.3); if the gap is <0.15mm, proceed to step 2.3.4);

[0045] 2.3.3) Disassemble the rectangular frame, add the re-cut fiber cloth to the corresponding position of the use mold surface of the hollow hexahedral component preform intermediate, and then re-mold it with the rectangular frame and return to step 2.3.2);

[0046] 2.3.4) Snap the front cover plate onto the front side of the rectangular frame, and then use the fastening assembly to fasten the outer mold assembly;

[0047] 2.3.5) Use a 0.15mm feeler gauge to detect the gap between the intermediate body of the hollow hexahedral component preform and the front cover plate. If the gap is ≥0.15mm, perform step 2.3.6). If the gap is <0.15mm, remove the rectangular frame and the front cover plate, and then sew and lock the edges to obtain the hollow hexahedral component preform;

[0048] 2.3.6) Remove the front cover, add the re-cut fiber cloth to the use surface of the hollow hexahedral component preform intermediate corresponding to the use surface of the front cover, then buckle the front cover to the front side of the rectangular frame again and fasten the outer mold assembly with the fastening assembly, and return to step 2.3.5).

[0049] Further, step 3) specifically includes the following steps:

[0050] 3.1) placing the hollow hexahedral component preform fastened in step 2.4) in a deposition furnace, heating it to 650-1000° C. at a pressure of 50-1000 Pa in the furnace, keeping it warm for 1-3 hours, then sequentially introducing argon, hydrogen, ammonia and boron trichloride gases for deposition until a hollow hexahedral component preform with a boron nitride interface layer of 150-750 nm thickness is obtained, and then cooling it to room temperature;

[0051] Alternatively, the hollow hexahedral component preform fastened in step 2.4) is placed in a deposition furnace, heated to 500-1000° C. at a pressure of 10-70 Pa in the furnace, kept warm for 1-3 hours, and then argon and propylene are introduced in sequence for deposition until a hollow hexahedral component preform with a pyrolytic carbon interface layer of 100-350 nm thickness is obtained, and then cooled to room temperature;

[0052] 3.2) Take out the hollow hexahedral component preform after deposition in step 3.1), remove the first positioning pin, then remove the inner mold adjustment plate, and then use the first positioning pin to reposition and connect the left inner mold and the right inner mold, and finally perform high temperature treatment at a temperature of 1750-2000°C for 1h-5h.

[0053] Further, step 5) is specifically as follows:

[0054] The hollow hexahedral component preform from which the outer mold assembly is removed in step 4.4) is machined, and then the silicon carbide matrix layer is deposited according to the method of steps 4.1) and 4.2) until the density of the silicon carbide matrix layer is greater than 2.0 g / cm 3 , a ceramic-based composite hollow hexahedral component was obtained.

[0055] Beneficial effects of the present invention:

[0056] 1. The present invention provides a shaping mold for a preform of a hollow hexahedral component of a ceramic-based composite material. The shaping mold is a modular structure, which not only improves the machinability of the complex surface of the mold, improves the convenience of transportation and operation, but also effectively reduces the preparation cost. In addition, the shaping mold has a relatively uniform holding force and a good fit with the fiber cloth, which can avoid defects such as stratification and pores in the hollow hexahedral component product, greatly improving the mechanical properties of the product.

[0057] 2. The uniform wall thickness profile provided by the present invention can effectively improve the deposition efficiency and deposition uniformity in the subsequent preparation process, reduce the preparation cost, and further improve the mechanical properties of the product. The breaking groove provided by the present invention can reduce the difficulty of removing the inner mold component, which is conducive to the removal of the inner mold component without affecting the use profile of the preform.

[0058] 3. The reinforcing frame and wedge block in the present invention can effectively improve the fitting rate of the mold, which can reach more than 85%, and the thickness difference of different parts of the preform is less than 0.3mm, thereby improving the uniformity of the wall thickness of the preform in the subsequent chemical vapor deposition process, reducing the risk of delamination, and further improving the mechanical properties of the hollow hexahedral component product. The reinforcing ribs in the present invention can significantly improve the strength and rigidity of the front cover without changing the wall thickness of the front cover.

[0059] 4. The present invention provides a method for preparing a hollow hexahedral component of a ceramic-based composite material. The method is simple to operate and has high reliability. The method can achieve high-quality shaping of a preform of a hollow hexahedral component with a complex profile. The method removes the inner mold adjustment plate before high-temperature treatment to avoid cracking of the component preform due to the different thermal expansion coefficients of the mold and the ceramic-based composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a schematic diagram of the installation structure of the left inner mold, the right inner mold and the inner mold adjustment plate in an embodiment of a shaping mold for a hollow hexahedral component preform of a ceramic-based composite material according to the present invention;

[0061] Figure 2 It is a structural schematic diagram of an inner mold assembly in an embodiment of a shaping mold for a hollow hexahedral component preform of a ceramic-based composite material according to the present invention;

[0062] Figure 3 It is a schematic structural diagram of a hollow hexahedral component preform intermediate in step 2.2) of an embodiment of a method for preparing a hollow hexahedral component of a ceramic-based composite material of the present invention;

[0063] Figure 4 It is a schematic structural diagram of an embodiment of a shaping mold for a hollow hexahedral component preform of a ceramic-based composite material according to the present invention after an upper outer mold and a lower outer mold are buckled together;

[0064] Figure 5 It is a structural schematic diagram of a hollow hexahedral component preform and an upper outer mold and a lower outer mold in an embodiment of a method for preparing a hollow hexahedral component of a ceramic-based composite material of the present invention;

[0065] Figure 6 It is a structural schematic diagram of a hollow hexahedral component preform, an upper outer mold, a lower outer mold and a front cover plate mold in an embodiment of a method for preparing a hollow hexahedral component of a ceramic-based composite material of the present invention;

[0066] Figure 7 It is a structural schematic diagram of a hollow hexahedral component preform, an outer mold component and a fastening component in an embodiment of a method for preparing a hollow hexahedral component of a ceramic-based composite material of the present invention.

[0067] Description of reference numerals:

[0068] 1-left inner mold; 2-right inner mold; 3-inner mold adjustment plate; 4-destruction groove; 5-first positioning hole; 6-first detection reference hole; 7-window front panel; 8-fastening assembly; 9-inner mold assembly; 10-hollow hexahedral component preform; 11-upper outer mold; 12-lower outer mold; 13-connecting ear piece; 14-stud bolt; 15-nut; 16-reinforcement rib; 17-front cover; 18-outer mold assembly; 19-reinforcement frame; 20-window rear panel; 21-rear cover; 22-second detection reference hole; 23-second positioning pin. DETAILED DESCRIPTION

[0069] When designing a molding die for a hollow hexahedral preform of a ceramic-based composite material in an embodiment of the present invention, factors such as the processing accessibility of complex surfaces, the fit rate with the fiber cloth, the ease of demolding, the protection of the preform during demolding, and the uniformity of deposition density during subsequent chemical vapor deposition should be comprehensively considered.

[0070] like Figure 1-Figure 7 As shown, a shaping mold for a preform of a hollow hexahedral component of a ceramic-based composite material comprises an inner mold assembly 9, an outer mold assembly 18, and a fastening assembly 8 for pressing the outer mold assembly 18. Specifically, the inner mold assembly 9 comprises a left inner mold 1, a right inner mold 2, an inner mold adjustment plate 3, two window front panels 7, and two first positioning pins, wherein the left inner mold 1 comprises an upper frame, a right frame, a lower frame, and a left frame which are sequentially closed into a rectangular frame structure, and a window rear panel 20 arranged at the rear side of the rectangular frame structure, the right frame of the left inner mold 1 is provided with two first positioning holes 5, the right inner mold 2 has the same structure as the left inner mold 1, the left frame of the right inner mold 2 is provided with two second positioning holes, and the left frame and the lower frame of the left inner mold 1 are provided with two second positioning holes. The lower frame and the right frame of the right inner mold 2 are provided with a plurality of evenly distributed breaking grooves 4, and the shape of the breaking grooves 4 can be rectangular, square, circular or irregular. Each first positioning pin can pass through the first positioning hole 5, the inner mold adjustment plate 3 and the second positioning hole in sequence. The two window opening front panels 7 are respectively buckled on the front side of the rectangular frame structure of the left inner mold 1 and the rectangular frame structure of the right inner mold 2. The height of the inner mold adjustment plate 3 along the up-down direction is less than the height of the two window opening front panels 7 close to the window edge in the up-down direction. The width of the inner mold adjustment plate 3 along the front-to-back direction is less than the distance between the window opening front panel 7 and the window opening rear panel 20. The wall thickness of the inner mold adjustment plate 3 is 1-5mm, and the material of the inner mold adjustment plate 3 is a ceramic-based composite material. Sewing holes are arranged on the use profile of the inner mold assembly 9, and the aperture of the sewing holes is 1.5-10mm, and the hole center distance between adjacent sewing holes is 1-15mm.

[0071] The outer mold assembly 18 is arranged on the outside of the inner mold assembly 9, and the use profile of the outer mold assembly 18 is compatible with the use profile of the inner mold assembly 9. The outer mold assembly 18 includes an upper outer mold 11, a lower outer mold 12, and a front cover plate 17. The upper outer mold 11 and the lower outer mold 12 are symmetrical structures, and are fastened into a rectangular frame with a rear cover plate 21 through four connecting ears 13, two second positioning pins 23, four stud bolts 14 and eight nuts 15. The second positioning pin 23 can avoid relative misalignment between the upper outer mold 11 and the lower outer mold 12, resulting in the inability to close the mold or the mold is not closed in place, thereby avoiding defects such as excessive wall thickness and wrinkles in the final product. The front cover plate 17 is buckled on the front side of the rectangular frame. The front cover plate 17 and the rear cover plate 21 are both window structures. The front cover plate 17, the window front panel 7, the window rear panel 20 and the rear cover plate 21 are arranged in sequence from front to back. A plurality of reinforcing ribs 16 are arranged on the front side of the front cover plate 17 and the rear side of the rear cover plate 21. A first detection reference hole 6 is arranged on the window rear panel 20, and a second detection reference hole 22 corresponding to the first detection reference hole 6 is arranged on the window front panel 7, the rear cover plate 21 and the front cover plate 17. The first detection reference hole 6 and the second detection reference hole 22 are used for re-inspection after returning to the factory. The fastening assembly 8 includes three reinforcement frames 19 and three wedge blocks. The three reinforcement frames 19 are sequentially sleeved outside the outer mold assembly 18. Each wedge block is respectively arranged between the corresponding reinforcement frame 19 and the outer mold assembly 18, and is used to press the outer mold assembly 18 in the front and rear directions. In this embodiment, the use profile of the inner mold assembly 9 is a uniform wall thickness profile along the thickness direction, and its wall thickness is 5-10 mm, and the use profile of the outer mold assembly 18 is a uniform wall thickness profile along the thickness direction, and its wall thickness is 8-12 mm. The materials of the inner mold assembly 9, the outer mold assembly 18 and the fastening assembly 8 are high-temperature materials, and the high-temperature materials can be high-strength fine graphite, high-purity graphite or electrode graphite.

[0072] like Figure 1-Figure 7 As shown, the present embodiment provides a method for preparing a hollow hexahedral component of a ceramic-based composite material, based on a shaping mold of the preform of the hollow hexahedral component of the ceramic-based composite material, comprising the following steps:

[0073] 1) Assemble the inner mold assembly 9

[0074] 1.1) Glue the left inner mold 1 to one of the window front panels 7, and glue the right inner mold 2 to the other window front panel 7;

[0075] 1.2) The left inner mold 1, the inner mold adjustment plate 3 and the right inner mold 2 are positioned and connected by a first positioning pin and then glued to form an inner mold assembly 9.

[0076] 2) The hollow hexahedral component preform 10 is shaped

[0077] 2.1) Calculate the amount of fiber cloth required for the hollow hexahedral component preform 10, leave an appropriate edge lock margin, and cut it;

[0078] 2.2) Laying and flanging the cut fiber cloth layer by layer on the use surface of the inner mold assembly 9 to obtain a hollow hexahedral component preform intermediate; wherein the layer thickness is 1.02-1.1 times the design thickness of the hollow hexahedral component preform, and flanging is performed alternately by right-angle flanging and bevel flanging, which can ensure the misalignment of the cutting edge, thereby avoiding cracks, delamination or even breakage due to stress concentration at the cutting edge during subsequent preparation or assessment;

[0079] 2.3) The hollow hexahedral component preform intermediate body and the rectangular frame and the front cover plate 17 formed by buckling the upper outer mold 11 and the lower outer mold 12 are tested for mold fitting. After the test mold fitting meets the requirements, the rectangular frame and the front cover plate 17 are removed, and then sewing and locking are performed to obtain the hollow hexahedral component preform 10; specifically:

[0080] 2.3.1) Test mold the hollow hexahedral component preform intermediate and the rectangular frame formed by buckling the upper outer mold 11 and the lower outer mold 12;

[0081] 2.3.2) Use a 0.15mm feeler gauge to detect the gap between the hollow hexahedral component preform intermediate and the rectangular frame use mold surface. If the gap is ≥0.15mm, proceed to step 2.3.3); if the gap is <0.15mm, proceed to step 2.3.4);

[0082] 2.3.3) Disassemble the rectangular frame, add the re-cut fiber cloth to the corresponding position of the use mold surface of the hollow hexahedral component preform intermediate, and then re-mold it with the rectangular frame and return to step 2.3.2);

[0083] 2.3.4) Snap the front cover plate 17 onto the front side of the rectangular frame, and then use the reinforcement frame 19 and the wedge block to fasten the outer mold assembly 18;

[0084] 2.3.5) Use a 0.15mm feeler gauge to detect the gap between the intermediate body of the hollow hexahedral component preform and the use surface of the front cover plate 17. If the gap is ≥0.15mm, perform step 2.3.6). If the gap is <0.15mm, remove the rectangular frame and the front cover plate 17, and then sew and lock the edges to obtain the hollow hexahedral component preform 10. In this embodiment, an in-situ sewing method is adopted. During the sewing process, the steel needle is perpendicular to the fiber cloth or the mold surface to avoid defects such as internal inclusions caused by sewing thread ends. The sewn fiber thread ends are left on the non-use surface of the mold. The locking requires no needle loss and the needle spacing gap is ≤3mm, which is used to prevent the hollow hexahedral component preform 10 from having defects such as stratification during the subsequent chemical vapor deposition process.

[0085] 2.3.6) Remove the front cover 17, add the newly cut fiber cloth to the use profile of the hollow hexahedral component preform intermediate corresponding to the use profile of the front cover 17, then re-fasten the front cover 17 to the front side of the rectangular frame and use the reinforcement frame 19 and the wedge block to fasten the outer mold assembly 18, and return to step 2.3.5).

[0086] 2.4) The hollow hexahedral component preform 10 and the rectangular frame formed by buckling the upper outer mold 11 and the lower outer mold 12 are molded together, and then the front cover plate 17 is buckled on the front side of the rectangular frame. Finally, the outer mold assembly 18 is fastened with a reinforcing frame 19 and a wedge block, and then a 0.15mm feeler gauge is used to detect the fitting gap between the hollow hexahedral component preform 10 and the upper outer mold 11, the lower outer mold 12, and the front cover plate 17. If the fitting gap is ≥0.15mm, the tightness of the reinforcing frame 19 is adjusted by adjusting the wedge block to a fitting gap of <0.15mm; if the fitting gap is <0.15mm, step 3) is performed.

[0087] 3) Preparation of interface layer and high temperature treatment

[0088] The interface layer of the hollow hexahedral component preform 10 fastened in step 2.4) is prepared by chemical vapor deposition, and then the inner mold adjustment plate 3 is removed, and then a high temperature treatment is performed; specifically:

[0089] 3.1) placing the hollow hexahedral component preform 10 fastened in step 2.4) in a deposition furnace, heating it to 500-1000°C at a furnace pressure of 10-70Pa, keeping it warm for 1-3h, then introducing argon and propylene for deposition in sequence until a hollow hexahedral component preform 10 with a pyrolytic carbon interface layer of 100-350nm thickness is obtained, and then cooling it to room temperature; in this embodiment, the furnace pressure is 60Pa, the temperature is raised to 800°C, and the temperature is kept warm for 3h, and the thickness of the pyrolytic carbon interface layer is 250Nm;

[0090] In other embodiments, step 3.1) may be: placing the hollow hexahedral component preform 10 tightened in step 2.4) in a deposition furnace, heating it to 650-1000° C. at a pressure of 50-1000 Pa in the furnace, keeping the temperature for 1-3 hours, and then sequentially introducing argon, hydrogen, ammonia and boron trichloride gas for deposition until a hollow hexahedral component preform 10 having a boron nitride interface layer with a thickness of 150-750 nm is obtained, and then cooling it to room temperature;

[0091] 3.2) Because the thermal expansion coefficients of the mold and the ceramic matrix composite material are different, the thermal expansion coefficient of graphite is: (1-3)×10 -6 / ℃, the thermal expansion coefficient of ceramic matrix composite materials is: (1-2.5)×10 -6 / ℃, it is easy to cause defects such as pits and wrinkles in the final product due to the difference in thermal expansion coefficients during high temperature treatment. Therefore, the hollow hexahedral component preform 10 deposited in step 3.1) is taken out, the first positioning pin is removed, and then the inner mold adjustment plate 3 is removed, and then the left inner mold 1 and the right inner mold 2 are repositioned and connected using the first positioning pin, and finally the high temperature treatment is carried out at a temperature of 1750-2000℃ for 1h-5h. In this embodiment, the temperature is 1900℃ and the high temperature treatment is carried out for 2h.

[0092] 4) preparing a silicon carbide substrate layer;

[0093] The hollow hexahedral component preform 10 treated in step 3) is subjected to a chemical vapor deposition method to prepare a silicon carbide matrix layer, and demoulding is performed during the process; specifically, as follows:

[0094] 4.1) placing the hollow hexahedral component preform 10 processed in step 3) in a deposition furnace, and setting the pressure in the furnace to 200-5000 Pa;

[0095] 4.2) Raise the temperature to 900-1200°C, keep warm for 1-2 hours, then introduce a mixed gas of trichloromethylsilane, hydrogen and argon, the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-20:10-30, deposit for 30-80 hours, keep warm for 2 hours, and then cool to room temperature;

[0096] 4.3) After repeating step 4.2) two to four times, take out the hollow hexahedral component preform 10 with the silicon carbide matrix layer, and remove the inner mold component 9 by knocking the inner mold component 9;

[0097] 4.4) The hollow hexahedral component preform 10 with the inner mold assembly 9 removed in step 4.3) is placed in a deposition furnace with a furnace pressure of 200-5000 Pa, and cyclic deposition is performed according to the process of step 4.2) until the density of the silicon carbide substrate layer is 1.75-1.8 g / cm 3 , remove the outer mold component 18. In this embodiment, the pressure in the furnace is 3000Pa, the temperature is raised to 900°C, and the temperature is kept for 2 hours. The flow ratio of trichloromethylsilane, hydrogen and argon is 1:10:10, and the deposition is carried out for 60 hours.

[0098] 5) Machining

[0099] The hollow hexahedral component preform 10 from which the outer mold assembly 18 is removed in step 4.4) is machined, and then the silicon carbide matrix layer is deposited according to the method of steps 4.1) and 4.2) until the density of the silicon carbide matrix layer is greater than 2.0 g / cm 3 , a ceramic-based composite hollow hexahedral component was obtained.

[0100] The above is only a specific embodiment 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 included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A shaping die for a preform of a hollow hexahedral component of a ceramic matrix composite material, characterized by: It comprises an inner mold component (9), an outer mold component (18), and a fastening component (8) for pressing the outer mold component (18); The inner mold assembly (9) comprises a left inner mold (1), a right inner mold (2), an inner mold adjustment plate (3), two window front panels (7) and at least two first positioning pins; the left inner mold (1) comprises an upper frame, a right frame, a lower frame and a left frame which are closed in sequence to form a rectangular frame structure, and a window rear panel (20) arranged at the rear side of the rectangular frame structure; the right frame of the left inner mold (1) is provided with at least two first positioning holes (5); the right inner mold (2) has the same structure as the left inner mold (1), and the left frame of the right inner mold (2) is provided with at least two first positioning holes (5); at least two second positioning holes; the first positioning pin can pass through the first positioning hole (5), the inner mold adjustment plate (3) and the second positioning hole in sequence; the two window opening front panels (7) are respectively buckled on the front sides of the rectangular frame structure of the left inner mold (1) and the rectangular frame structure of the right inner mold (2); the height of the inner mold adjustment plate (3) in the up-down direction is smaller than the height of the two window opening front panels (7) close to the window edge in the up-down direction, and the width of the inner mold adjustment plate (3) in the front-to-back direction is smaller than the distance between the window opening front panel (7) and the window opening rear panel (20); The inner mold component (9) is provided with sewing holes on its use profile; The outer mold component (18) is arranged outside the inner mold component (9), and the use profile of the outer mold component (18) is adapted to the use profile of the inner mold component (9); the outer mold component (18) comprises an upper outer mold (11), a lower outer mold (12), and a front cover plate (17); the upper outer mold (11) and the lower outer mold (12) are symmetrical structures, and are buckled together by a plurality of connecting ears (13) to form a rectangular frame with a rear cover plate (21); the front cover plate (17) is buckled on the front side of the rectangular frame; the front cover plate (17) and the rear cover plate (21) are both window structures; The front cover plate (17), the window front panel (7), the window rear panel (20) and the rear cover plate (21) are arranged in sequence from front to back.

2. The shaping mold for the preform of the hollow hexahedral component of the ceramic matrix composite material according to claim 1, characterized in that: The use profile of the inner mold assembly (9) is a profile with a constant wall thickness in the thickness direction, and its wall thickness is 5-10 mm; The use profile of the outer mold component (18) is a profile with a constant wall thickness in the thickness direction, and its wall thickness is 8-12 mm; The wall thickness of the inner mold adjustment plate (3) is 1-5 mm.

3. The shaping mold for the preform of the hollow hexahedral component of the ceramic matrix composite material according to claim 1 or 2, characterized in that: The left frame and the lower frame of the left inner mold (1) and the lower frame and the right frame of the right inner mold (2) are provided with a plurality of breaking grooves (4); The diameter of the sewing holes is 1.5-10 mm, and the distance between the centers of adjacent sewing holes is 1-15 mm.

4. The shaping mold for the preform of the hollow hexahedral component of the ceramic matrix composite material according to claim 3, characterized in that: The fastening assembly (8) comprises a plurality of reinforcing frames (19) and wedge blocks; the reinforcing frames (19) are sleeved outside the outer mold assembly (18), and the wedge blocks are arranged between the reinforcing frames (19) and the outer mold assembly (18) to press the outer mold assembly (18) in the front-rear direction; The window rear panel (20) is provided with a first detection reference hole (6); the window front panel (7), the rear cover plate (21) and the front cover plate (17) are provided with a second detection reference hole (22) corresponding to the first detection reference hole (6); the first detection reference hole (6) and the second detection reference hole (22) are used for factory re-inspection.

5. The shaping mold for the preform of the hollow hexahedral component of the ceramic matrix composite material according to claim 4, characterized in that: A plurality of reinforcing ribs (16) are provided on the front side surface of the front cover plate (17) and the rear side surface of the rear cover plate (21); The shape of the breaking groove (4) is rectangular, square, circular or irregular; The material of the inner mold adjustment plate (3) is a ceramic-based composite material; The materials of the inner mold component (9), the outer mold component (18) and the fastening component (8) are high-temperature materials; the high-temperature materials are high-strength fine graphite, high-purity graphite or electrode graphite.

6. A method for preparing a hollow hexahedral component of a ceramic-based composite material, based on the shaping mold of the preform of the hollow hexahedral component of the ceramic-based composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Assemble the inner mold components (9) 1.1) gluing the left inner mold (1) to one of the window front panels (7), and gluing the right inner mold (2) to the other window front panel (7); 1.2) Using a first positioning pin, the left inner mold (1), the inner mold adjustment plate (3) and the right inner mold (2) are positioned and connected, and then glued together to form an inner mold assembly (9); 2) Forming of the hollow hexahedral component preform (10) 2.1) Calculating the amount of fiber cloth required for the hollow hexahedral component preform (10) and cutting it; 2.2) Laying and flanging the cut fiber cloth layer by layer on the service surface of the inner mold assembly (9) to obtain a hollow hexahedral component preform intermediate; 2.3) Test-fit the hollow hexahedral component preform intermediate body and the rectangular frame and front cover plate (17) formed by buckling the upper outer mold (11) and the lower outer mold (12). After the test-fit meets the requirements, the rectangular frame and the front cover plate (17) are removed, and then sewing and locking are performed to obtain the hollow hexahedral component preform (10); 2.4) The hollow hexahedral component preform (10) and the upper outer mold (11) and the lower outer mold (12) are buckled together to form a rectangular frame, and then the front cover plate (17) is buckled on the front side of the rectangular frame, and finally the outer mold assembly (18) is fastened with a fastening assembly (8); 3) Preparation of interface layer and high temperature treatment The interface layer of the hollow hexahedral component preform (10) fastened in step 2.4) is prepared by chemical vapor deposition, and then the inner mold adjustment plate (3) is removed, and then high temperature treatment is performed; 4) preparing a silicon carbide substrate layer; The hollow hexahedral component preform (10) treated in step 3) is subjected to a chemical vapor deposition method to prepare a silicon carbide matrix layer, and demoulding is performed during the process; 5) Machining The hollow hexahedral component preform (10) on which the silicon carbide matrix layer is prepared is subjected to mechanical processing and subsequent treatment to obtain a hollow hexahedral component of a ceramic-based composite material.

7. The method for preparing a hollow hexahedral component of a ceramic-based composite material according to claim 6, characterized in that: Step 4) specifically includes the following steps: 4.1) placing the hollow hexahedral component preform (10) processed in step 3) in a deposition furnace, and setting the pressure in the furnace to 200-5000 Pa; 4.2) Raise the temperature to 900-1200°C, keep warm for 1-2 hours, then introduce a mixed gas of trichloromethylsilane, hydrogen and argon, the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-20:10-30, deposit for 30-80 hours, keep warm for 2 hours, and then cool to room temperature; 4.3) After repeating step 4.2) two to four times, take out the hollow hexahedral component preform (10) with the silicon carbide matrix layer, and remove the inner mold component (9) by knocking the inner mold component (9); 4.4) The hollow hexahedral component preform (10) from which the inner mold assembly (9) is removed in step 4.3) is placed in a deposition furnace with an internal pressure of 200-5000 Pa, and cyclic deposition is performed according to the process of step 4.2) until the density of the silicon carbide substrate layer is 1.75-1.8 g / cm3, and the outer mold assembly (18) is removed.

8. The method for preparing a hollow hexahedral component of a ceramic-based composite material according to claim 7, characterized in that: Step 2.3) specifically includes the following steps: 2.3.1) Test mold-fitting the hollow hexahedral component preform intermediate body and the rectangular frame formed by buckling the upper outer mold (11) and the lower outer mold (12); 2.3.2) Use a 0.15mm feeler gauge to detect the gap between the hollow hexahedral component preform intermediate and the rectangular frame use mold surface. If the gap is ≥0.15mm, proceed to step 2.3.3); if the gap is <0.15mm, proceed to step 2.3.4); 2.3.3) Disassemble the rectangular frame, add the re-cut fiber cloth to the corresponding position of the use mold surface of the hollow hexahedral component preform intermediate, and then re-mold it with the rectangular frame and return to step 2.3.2); 2.3.4) snapping the front cover plate (17) onto the front side of the rectangular frame, and then fastening the outer mold assembly (18) with the fastening assembly (8); 2.3.5) Using a 0.15 mm feeler gauge, check the gap between the hollow hexahedral component preform intermediate and the front cover plate (17) using the mold surface. If the gap is ≥ 0.15 mm, execute step 2.3.6). If the gap is < 0.15 mm, remove the rectangular frame and the front cover plate (17), and then sew and lock the edges to obtain the hollow hexahedral component preform (10). 2.3.6) Remove the front cover plate (17), add the newly cut fiber cloth to the use profile of the hollow hexahedral component preform intermediate corresponding to the use profile of the front cover plate (17), then buckle the front cover plate (17) to the front side surface of the rectangular frame again and fasten the outer mold component (18) with the fastening component (8), and return to step 2.3.5).

9. The method for preparing a hollow hexahedral component of a ceramic-based composite material according to claim 8, characterized in that: Step 3) specifically includes the following steps: 3.1) placing the hollow hexahedral component preform (10) tightened in step 2.4) in a deposition furnace, heating it to 650-1000° C. at a pressure of 50-1000 Pa in the furnace, keeping the temperature for 1-3 hours, then sequentially introducing argon, hydrogen, ammonia and boron trichloride gases for deposition until a hollow hexahedral component preform (10) having a boron nitride interface layer with a thickness of 150-750 nm is obtained, and then cooling it to room temperature; Alternatively, the hollow hexahedral component preform (10) tightened in step 2.4) is placed in a deposition furnace, heated to 500-1000° C. at a pressure of 10-70 Pa in the furnace, kept warm for 1-3 hours, and then argon and propylene are introduced in sequence for deposition until a hollow hexahedral component preform (10) having a pyrolytic carbon interface layer with a thickness of 100-350 nm is obtained, and then cooled to room temperature; 3.2) Take out the hollow hexahedral component preform (10) deposited in step 3.1), remove the first positioning pin, then remove the inner mold adjustment plate (3), and then use the first positioning pin to reposition and connect the left inner mold (1) and the right inner mold (2), and finally perform high temperature treatment at a temperature of 1750 to 2000° C. for 1 h to 5 h.

10. The method for preparing a hollow hexahedral component of a ceramic-based composite material according to claim 9, characterized in that: Step 5) is specifically: The hollow hexahedral component preform (10) from which the outer mold assembly (18) is removed in step 4.4) is machined, and then the silicon carbide matrix layer is deposited according to the methods of steps 4.1) and 4.2) until the density of the silicon carbide matrix layer is greater than 2.0 g / cm3, thereby obtaining a hollow hexahedral component of a ceramic-based composite material.

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