Preparation method of ceramic matrix composite blade

Abstract

The invention provides a preparation method of a ceramic matrix composite blade. The preparation method can solve the problems that according to an existing preparation method of the ceramic matrix composite blade, the fiber continuity proportion of the obtained blade is small, and the strength, rigidity and other mechanical properties of the blade are poor. The method comprises the following steps: establishing a middle-sized surface; designing a blade body upper molded surface and a blade body lower molded surface, respectively reserving machining allowances in the thickness direction, and reserving machining allowances on the two sides and the front end of the obtained blade body middle body to obtain a blade body prefabricated body; extending towards the tenon direction by taking the middle-sized surface as a basis to form an extending surface, designing a tenon upper molded surface and a tenon lower molded surface, respectively reserving machining allowances in the thickness direction, and reserving machining allowances on the two sides of the obtained tenon middle body to obtain a tenon prefabricated body and form a blade prefabricated body; manufacturing a shaping mold; the laying layer number and the cutting size of the blade body fiber cloth and the tenon fiber cloth are determined, and then shaping is conducted; sewing and edge locking are carried out; performing deposition treatment; after the shaping mold is removed, machining and deposition treatment are conducted, and the blade is obtained.

Description

Technical Field

[0001] The invention relates to a method for preparing an aero-engine component, and in particular to a method for preparing a ceramic-based composite material blade. Background Art

[0002] With the rapid development of aerospace technology, the requirements for aircraft engine performance are increasing. As one of the key components of aircraft engines, blades need to withstand large loads under harsh environments such as high temperature and high pressure, and need to have high stability under harsh environments. Therefore, blades need to have high strength and high stiffness. The strength and stiffness of blades mainly depend on the proportion of fiber continuity in the preparation process. This requires that when designing blade preforms, not only the design structure, shape, size, laying method, difficulty of shaping, damage defects of preforms and reserved processing volume, thermal expansion matching between materials and tooling, deposition efficiency and loss rate, etc., but also the proportion of fiber continuity needs to be fully considered. Figure 1 This is a schematic diagram of the three-dimensional structure of an existing blade, wherein the blade 01 includes a blade body 02 and a tenon 03. At present, a ceramic-based composite blade is usually prepared by first preparing the blade body 02 and the tenon 03 separately, and then riveting the blade body 02 and the tenon 03. However, the problem with this preparation method is that the fiber continuity of the prepared blade is small, and the mechanical properties of the blade, such as strength and stiffness, are poor. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems that the existing method for preparing ceramic-based composite blades has a small proportion of fiber continuity in the prepared blades and poor mechanical properties such as strength and stiffness of the blades, and to provide a method for preparing ceramic-based composite blades.

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

[0005] A method for preparing a ceramic-based composite blade, the blade comprising a blade body and a tenon; the tenon is connected to the tail end of the blade body; the method is special in that it comprises the following steps:

[0006] Step 1: Design the blade preform

[0007] Step 1.1, establishing a middle profile according to the upper profile curvature and the lower profile curvature of the blade body;

[0008] Step 1.2, designing the blade upper profile and the blade lower profile based on the middle profile, and then reserving 0.5-1.0 mm machining allowance in the thickness direction of the blade upper profile and the blade lower profile to obtain a blade intermediate, and reserving 5.0-10 mm machining allowance on both sides and the front end of the blade intermediate to obtain a blade preform;

[0009] Step 1.3, based on the middle surface, extend in the direction of the tenon to exceed the tenon tail by 5.0 to 10 mm to form an extension surface, then design the tenon upper profile surface and the tenon lower profile surface based on the extension surface, and then reserve 0.5 to 1.0 mm machining allowance in the thickness direction of the tenon upper profile surface and the tenon lower profile surface respectively to obtain a tenon intermediate body; reserve 5.0 to 10 mm machining allowance on both sides of the tenon intermediate body to obtain a tenon preform; the tenon preform and the blade body preform constitute a blade preform;

[0010] Step 2, making a shaping mold according to the blade preform;

[0011] Step 3, determining the number of plies of the blade fiber cloth and the tenon fiber cloth according to the thickness of the blade preform and the tenon preform; determining the cutting size of the blade fiber cloth and the tenon fiber cloth according to the size of the blade preform and the tenon preform, and cutting them;

[0012] Step 4, using the shaping mold and the blade body fiber cloth and tenon fiber cloth cut in step 3 to shape the blade preform;

[0013] Step 5, sewing and locking the shaped blade preform;

[0014] Step 6: using chemical vapor deposition to sequentially perform interface layer deposition and silicon carbide substrate layer deposition on the edge-locked blade preform;

[0015] Step 7: remove the shaping mold, perform mechanical processing on the blade preform after the deposition treatment, and then perform silicon carbide matrix deposition treatment to obtain a ceramic-based composite material blade.

[0016] Further, in step 2, the shaping mold includes an upper mold, a lower mold and at least two fastening components;

[0017] The mounting profile of the upper mold includes a first arcuate convex surface and a second arcuate convex surface, the first arcuate convex surface is matched with the upper profile of the tenon preform, and the second arcuate convex surface is matched with the upper profile of the blade body preform; the mounting profile of the upper mold is provided with a first sewing hole; and two corner positions of the upper mold are provided with first positioning holes;

[0018] The installation profile of the lower mold includes a first arc-shaped concave surface and a second arc-shaped concave surface, the first arc-shaped concave surface is adapted to the lower profile of the tenon preform, and the second arc-shaped concave surface is adapted to the lower profile of the blade body preform; the installation profile of the lower mold is provided with a second sewing hole corresponding to the first sewing hole; the lower mold is provided with a second positioning hole corresponding to the first positioning hole;

[0019] The fastening assembly is used to fasten the upper mold and the lower mold after mold closing;

[0020] Step 4 specifically includes the following steps:

[0021] Step 4.1, stacking and laying the blade fiber cloth cut in step 3 on the second curved convex surface, and then stacking and laying the tenon fiber cloth cut in step 3 on the first curved convex surface until it is flush with the outermost blade fiber cloth, and finally stacking and laying the remaining tenon fiber cloth on the first curved concave surface to obtain the stacked upper mold and lower mold;

[0022] Alternatively, the blade body fiber cloth cut in step 3 is laminated and laid on the second arc-shaped concave surface, and then the tenon fiber cloth cut in step 3 is laminated and laid on the first arc-shaped concave surface until it is flush with the outermost blade body fiber cloth, and finally the remaining tenon fiber cloth is laminated and laid on the first arc-shaped convex surface to obtain the laminated upper mold and lower mold;

[0023] Step 4.2, closing the laminated upper mold and lower mold, and fastening them with a fastening assembly to obtain a shaped blade preform;

[0024] Step 4.3: Use a 0.15mm feeler gauge to detect the gap between the preformed blade and the upper mold and the lower mold. If the gap is ≥0.15mm, proceed to step 4.4; if the gap is <0.15mm, proceed to step 5.

[0025] Step 4.4, disassemble the fastening components, add the re-cut blade body fiber cloth and tenon fiber cloth to the outermost blade body fiber cloth and tenon fiber cloth, and return to step 4.2.

[0026] Furthermore, in step 2, the diameters of the first sewing holes and the second sewing holes are both 3 to 5 mm, and the distances between adjacent first sewing holes and adjacent second sewing holes are both 5 to 8 mm;

[0027] The mounting profile of the upper mold and the mounting profile of the lower mold are both profiles of equal wall thickness.

[0028] Furthermore, in step 3, the cutting size of the blade body fiber cloth and the tenon fiber cloth reserves a 6-10 mm edge locking margin.

[0029] Furthermore, step 5 is specifically as follows:

[0030] The shaped blade preform is sewn through and then edge-locked; the edge-locking needs to meet the following conditions: no needle fall-off, and the stitch gap is ≤3mm.

[0031] Furthermore, step 6 specifically includes the following steps:

[0032] Step 6.1, placing the edge-locked blade preform in a chemical vapor deposition furnace, and then heating it to 650-1000°C under the condition of a furnace pressure of 50-1000Pa, and then sequentially introducing argon, hydrogen, ammonia and boron trichloride gases for deposition for 1-3 hours, until a blade preform with a boron nitride interface layer with a thickness of 150-750nm is obtained, and then the temperature is kept for 1-3 hours, and then cooled to room temperature;

[0033] Alternatively, the edge-locked blade preform is placed in a chemical vapor deposition furnace, and then the temperature is raised to 500-1000°C under the condition of a furnace pressure of 10-70 Pa, and argon gas and propylene gas are introduced in sequence for deposition after being kept at this temperature for 1-3 hours, until a blade preform with a pyrolytic carbon interface layer with a thickness of 100-350 nm is obtained, and the temperature is kept at this temperature for 1-3 hours, and then the temperature is lowered to room temperature;

[0034] Step 6.2: Under the condition of a furnace pressure of 200-5000Pa, the temperature is raised to 900-1200°C, and after keeping the temperature for 1-2h, a mixed gas of trichloromethylsilane, hydrogen and argon is introduced, and the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-12:10-30, and the blade preform obtained in step 6.1 is deposited until a blade preform having a carbon fiber thickness of 1.7-1.8g / cm 3 The blade preform with a dense silicon carbide matrix layer is kept warm for 1-3 hours and then cooled to room temperature.

[0035] Furthermore, step 7 is specifically as follows:

[0036] Remove the upper mold and the lower mold, first perform mechanical processing on the blade preform obtained in step 6.2, and then perform silicon carbide substrate deposition processing according to the deposition method in step 6.2 until the density of the silicon carbide substrate layer is greater than 2.4g / cm 3 , and obtain a ceramic matrix composite blade.

[0037] Further, in step 2, each of the fastening assemblies includes two pressure strips, two stud bolts and four nuts;

[0038] The two pressure strips are used to abut against the opposite surface of the mounting profile of the upper mold and the opposite surface of the mounting profile of the lower mold respectively;

[0039] The two stud bolts are used to penetrate the two ends of the two pressure strips respectively and are fastened by four nuts.

[0040] Furthermore, the material of the shaping mold is a high temperature resistant material.

[0041] Furthermore, the shaping mold is made of high-strength fine graphite material, high-purity graphite material or electrode graphite material.

[0042] Beneficial effects of the present invention:

[0043] 1. The present invention provides a method for preparing a ceramic-based composite blade. The blade preform and the tenon preform are designed corresponding to the mid-profile surface and the extension surface, thereby obtaining the design of the blade preform. This method can effectively increase the proportion of continuous fibers on the mid-profile surface and the extension surface of the blade, and at the same time ensure that the fibers at the connection position between the tenon and the blade are continuous, thereby improving the mechanical properties of the blade and ensuring that it has high strength and stiffness.

[0044] 2. The present invention can effectively prevent the occurrence of delamination defects and significantly improve the final mechanical properties of the blade by detecting the fitting gap, reasonably setting the aperture and hole spacing parameters of the first sewing hole and the second sewing hole, and combining the subsequent edge locking operation.

[0045] 3. The shaping mold in the present invention has a simple structure and is easy to operate. Since the mounting surfaces of the upper mold and the lower mold are both surfaces of equal wall thickness, the deposition efficiency and deposition uniformity in the subsequent preparation process can be effectively improved under the premise of efficiently shaping the blade preform, which can shorten the preparation cycle, reduce economic costs, and effectively improve the mechanical properties of the blade preform. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the three-dimensional structure of an existing blade;

[0047] Figure 2 It is a schematic structural diagram of a blade preform in step 1 of an embodiment of a method for preparing a ceramic-based composite blade of the present invention;

[0048] Figure 3 yes Figure 2 Schematic diagram of the three-dimensional structure of the middle blade body preform;

[0049] Figure 4 It is a schematic diagram of the three-dimensional structure of the shaping mold and the shaped blade preform in step 4 of the embodiment of the present invention;

[0050] Figure 5 It is a three-dimensional structural schematic diagram of the shaping mold and the shaped blade preform from another perspective in step 4 of the embodiment of the present invention;

[0051] Figure 6 It is a three-dimensional structural schematic diagram of the shaping mold and the shaped blade preform from another perspective in step 4 of the embodiment of the present invention.

[0052] Description of reference numerals:

[0053] 01-blade, 02-blade body, 03-tenon, 3-upper mold, 4-lower mold, 5-nut, 6-pressing strip, 7-stud bolt, 8-fastening assembly, 9-first sewing hole, 10-first positioning hole, 11-second sewing hole, 12-second positioning hole, 21-tenon preform, 22-blade preform, 23-blade body preform, 24-middle surface. DETAILED DESCRIPTION

[0054] A method for preparing a ceramic matrix composite blade, such as Figure 1-Figure 3 As shown, the blade 01 includes a blade body 02 and a tenon 03, and the tenon 03 is connected to the tail end of the blade body 02. The preparation method includes the following steps:

[0055] Step 1: Design the blade preform 22

[0056] Step 1.1, establishing a middle profile 24 according to the upper profile curvature and the lower profile curvature of the blade body 02;

[0057] Step 1.2, designing the blade upper profile and the blade lower profile based on the middle profile 24, and then reserving 0.5-1.0 mm machining allowance in the thickness direction of the blade upper profile and the blade lower profile (reserving 0.5 mm machining allowance in this embodiment) to obtain a blade intermediate body, and reserving 5.0-10 mm machining allowance on both sides and the front end of the blade intermediate body (reserving 8 mm machining allowance in this embodiment) to obtain a blade preform 23;

[0058] Step 1.3, based on the middle surface 24, extend in the direction of the tenon 03 to exceed the tail of the tenon 03 by 5.0 to 10 mm (in this embodiment, an 8 mm machining allowance exceeds the tail of the tenon 03) to form an extension surface, and then design the tenon upper profile and the tenon lower profile based on the extension surface, and then reserve 0.5 to 1.0 mm machining allowance in the thickness direction of the tenon upper profile and the tenon lower profile respectively (in this embodiment, a 0.5 mm machining allowance is reserved) to obtain the tenon intermediate; reserve 5.0 to 10 mm machining allowance on both sides of the tenon intermediate (in this embodiment, an 8 mm machining allowance is reserved) to obtain the tenon preform 21, and the tenon preform 21 and the blade body preform 23 constitute the blade preform 22.

[0059] Step 2: Make a shaping mold based on the blade preform 22, such as Figure 4-Figure 6As shown, the shaping mold includes an upper mold 3, a lower mold 4 and two fastening components 8. Specifically, the mounting profile of the upper mold 3 includes a first arcuate convex surface and a second arcuate convex surface, the first arcuate convex surface is matched with the upper profile of the tenon preform 21, and the second arcuate convex surface is matched with the upper profile of the blade preform 23. The mounting profile of the upper mold 3 is provided with a first sewing hole 9, and two corner positions of the upper mold 3 are provided with a first positioning hole 10. The mounting profile of the lower mold 4 includes a first arcuate concave surface and a second arcuate concave surface, the first arcuate concave surface is matched with the lower profile of the tenon preform 21, and the second arcuate concave surface is matched with the lower profile of the blade preform 23. The mounting profile of the lower mold 4 is provided with a second sewing hole 11 corresponding to the first sewing hole 9, and the lower mold 4 is provided with a second positioning hole 12 corresponding to the first positioning hole 10. The mounting profile of the upper mold 3 and the mounting profile of the lower mold 4 are both equal wall thickness profiles. The diameters of the first sewing holes 9 and the second sewing holes 11 are both 3-5 mm, and the distances between adjacent first sewing holes 9 and adjacent second sewing holes 11 are both 5-8 mm.

[0060] Each fastening assembly 8 includes two pressure strips 6, two stud bolts 7 and four nuts 5. The two pressure strips 6 are respectively used to abut against the opposite surfaces of the mounting surface of the upper mold 3 and the opposite surfaces of the mounting surface of the lower mold 4. The two stud bolts 7 are respectively used to pass through the two ends of the two pressure strips 6 and are fastened by four nuts 5.

[0061] In this embodiment, the material of the shaping mold is high-strength fine graphite material. The apertures of the first sewing hole 9 and the second sewing hole 11 are both 3 mm, and the hole spacings between adjacent first sewing holes 9 and adjacent second sewing holes 11 are both 5 mm. In other embodiments, the material of the shaping mold may be high-purity graphite material or electrode graphite material.

[0062] Step 3: Determine the number of plies of the blade fiber cloth and the tenon fiber cloth according to the thickness of the blade preform 23 and the tenon preform 21; determine the cutting size of the blade fiber cloth and the tenon fiber cloth according to the size of the blade preform 23 and the tenon preform 21, and cut them; wherein, the cutting size of the blade fiber cloth and the tenon fiber cloth is reserved with 6 to 10 mm lock edge margin to avoid stratification in the subsequent preparation process due to non-lock edge. In this embodiment, a 10 mm lock edge margin is reserved.

[0063] It should be noted that, in other embodiments, the processing allowances reserved in steps 1.2 and 1.3, the apertures of the first sewing holes 9 and the second sewing holes 11 in step 2, the hole spacing between adjacent first sewing holes 9 and adjacent second sewing holes 11, and the hemming allowance reserved in step 3 can be flexibly adjusted.

[0064] Step 4: Shaping of the blade preform 22

[0065] Step 4.1, stacking and laying the blade fiber cloth cut in step 3 on the second curved convex surface, and then stacking and laying the tenon fiber cloth cut in step 3 on the first curved convex surface until it is flush with the outermost blade fiber cloth, and finally stacking and laying the remaining tenon fiber cloth on the first curved concave surface to obtain the stacked upper mold 3 and lower mold 4;

[0066] In other embodiments, the step is specifically as follows: the blade fiber cloth cut in step 3 is laminated and laid on the second arc-shaped concave surface, and then the tenon fiber cloth cut in step 3 is laminated and laid on the first arc-shaped concave surface until it is flush with the outermost blade fiber cloth, and finally the remaining tenon fiber cloth is laminated and laid on the first arc-shaped convex surface to obtain the laminated upper mold 3 and the lower mold 4;

[0067] Step 4.2: The laminated upper mold 3 and the lower mold 4 are molded together and fastened with a fastening assembly 8 to obtain a shaped blade preform 22, as shown in FIG. Figure 4-Figure 6 As shown;

[0068] Step 4.3, using a 0.15mm feeler gauge to detect the gap between the finalized blade preform 22 and the upper mold 3 and the lower mold 4, if the gap is ≥ 0.15mm, then execute step 4.4; if the gap is < 0.15mm, then execute step 5;

[0069] Step 4.4, disassemble the fastening assembly 8, add the re-cut blade body fiber cloth and tenon fiber cloth to the outermost blade body fiber cloth and tenon fiber cloth, and return to step 4.2.

[0070] Step 5, the blade preform 22 after shaping is sewed, during which the steel needle is perpendicular to the surface of the shaping mold, the sewn connector is left on the non-installation surface of the shaping mold, and then the edge is locked. The edge locking needs to meet the following conditions: no needle falling off, the needle spacing gap is ≤3mm, which is used to prevent defects such as stratification during the subsequent chemical vapor deposition process.

[0071] Step 6: using chemical vapor deposition to sequentially perform interface layer deposition and silicon carbide substrate layer deposition on the edge-locked blade preform 22; specifically, the following steps are included:

[0072] Step 6.1, place the edge-locked blade preform 22 in a chemical vapor deposition furnace, and then heat it to 650-1000°C under the condition of a furnace pressure of 50-1000Pa. After keeping it warm for 1-3 hours, introduce argon, hydrogen, ammonia and boron trichloride gas in turn for deposition until a blade preform 22 with a boron nitride interface layer with a thickness of 150-750nm is obtained. Continue to keep it warm for 1-3 hours, and then cool it to room temperature. In this embodiment, the pressure in the furnace is 850Pa, the temperature is raised to 950°C, and it is kept warm for 3 hours.

[0073] In other embodiments, the step is specifically as follows: placing the edge-locked blade preform 22 in a chemical vapor deposition furnace, and then heating it to 500-1000° C. under a furnace pressure of 10-70 Pa, and then sequentially introducing argon gas and propylene gas for deposition after keeping the temperature for 1-3 hours, until a blade preform 22 having a pyrolytic carbon interface layer with a thickness of 100-350 nm is obtained, and then keeping the temperature for 1-3 hours, and then cooling to room temperature;

[0074] Step 6.2: Under the condition of a furnace pressure of 200-5000Pa, the temperature is raised to 900-1200°C, and after keeping the temperature for 1-2h, a mixed gas of trichloromethylsilane, hydrogen and argon is introduced, and the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-12:10-30, and the blade preform 22 obtained in step 6.1 is deposited until a 1.7-1.8g / cm 3 The blade preform 22 with a high density silicon carbide matrix layer is kept warm for 1-3 hours and then cooled to room temperature. In this embodiment, the pressure in the furnace is 3000 Pa, the temperature is raised to 1100° C., and kept warm for 2 hours. The flow ratio of trichloromethylsilane, hydrogen and argon is 1:10:10.

[0075] Step 7: Remove the upper mold 3 and the lower mold 4, perform mechanical processing on the blade preform 22 obtained in step 6.2, and then perform silicon carbide matrix deposition processing according to the deposition method in step 6.2 until the density of the silicon carbide matrix layer is greater than 2.4 g / cm 3 , and obtain a ceramic matrix composite blade.

[0076] It should be noted that the process parameters of the deposition process in step 6 are mature processes and can be flexibly adjusted by those skilled in the art.

[0077] 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 method for preparing a ceramic-based composite blade, wherein the blade (01) comprises a blade body (02) and a tenon (03); the tenon (03) is connected to the tail end of the blade body (02); characterized in that: The following steps are involved: Step 1: Design the blade preform (22) Step 1.1, establishing a middle profile (24) according to the upper profile curvature and the lower profile curvature of the blade body (02); Step 1.2, designing a blade body upper profile and a blade body lower profile based on the middle profile (24), and then reserving 0.5-1.0 mm machining allowance in the thickness direction of the blade body upper profile and the blade body lower profile respectively to obtain a blade body intermediate body, and reserving 5.0-10 mm machining allowance on both sides and the front end of the blade body intermediate body to obtain a blade body preform (23); Step 1.3, based on the middle profile (24), extend in the direction of the tenon (03) to exceed the tail of the tenon (03) by 5.0 to 10 mm to form an extension surface, then design the tenon upper profile and the tenon lower profile based on the extension surface, and then reserve 0.5 to 1.0 mm of machining allowance in the thickness direction of the tenon upper profile and the tenon lower profile respectively to obtain a tenon intermediate body; reserve 5.0 to 10 mm of machining allowance on both sides of the tenon intermediate body to obtain a tenon preform (21); the tenon preform (21) and the blade body preform (23) constitute a blade preform (22); Step 2, making a shaping mold according to the blade preform (22); Step 3, determining the number of plies of the blade fiber cloth and the tenon fiber cloth according to the thickness of the blade preform (23) and the tenon preform (21); determining the cutting sizes of the blade fiber cloth and the tenon fiber cloth according to the sizes of the blade preform (23) and the tenon preform (21), and cutting them; Step 4, using the shaping mold and the blade body fiber cloth and tenon fiber cloth cut in step 3 to shape the blade preform (22); Step 5, sewing and locking the shaped blade preform (22); Step 6: using chemical vapor deposition to sequentially perform interface layer deposition and silicon carbide substrate layer deposition on the edge-locked blade preform (22); Step 7: remove the shaping mold, perform mechanical processing on the blade preform (22) after the deposition treatment, and then perform silicon carbide matrix deposition treatment to obtain a ceramic matrix composite material blade.

2. The method for preparing a ceramic matrix composite blade according to claim 1, characterized in that: In step 2, the shaping mold comprises an upper mold (3), a lower mold (4) and at least two fastening components (8); The mounting profile of the upper mold (3) comprises a first arc-shaped convex surface and a second arc-shaped convex surface, the first arc-shaped convex surface is matched with the upper profile of the tenon preform (21), and the second arc-shaped convex surface is matched with the upper profile of the blade body preform (23); the mounting profile of the upper mold (3) is provided with a first sewing hole (9); and first positioning holes (10) are provided at two corner positions of the upper mold (3); The mounting profile of the lower mold (4) comprises a first arc-shaped concave surface and a second arc-shaped concave surface, the first arc-shaped concave surface is adapted to the lower profile of the tenon preform (21), and the second arc-shaped concave surface is adapted to the lower profile of the blade body preform (23); a second sewing hole (11) corresponding to the first sewing hole (9) is arranged on the mounting profile of the lower mold (4); and a second positioning hole (12) corresponding to the first positioning hole (10) is arranged on the lower mold (4); The fastening assembly (8) is used to fasten the upper mold (3) and the lower mold (4) after mold closing; Step 4 specifically includes the following steps: Step 4.1, stacking and laying the blade fiber cloth cut in step 3 on the second curved convex surface, and then stacking and laying the tenon fiber cloth cut in step 3 on the first curved convex surface until it is flush with the outermost blade fiber cloth, and finally stacking and laying the remaining tenon fiber cloth on the first curved concave surface to obtain the stacked upper mold (3) and lower mold (4); Alternatively, the blade body fiber cloth cut in step 3 is stacked and laid on the second curved concave surface, and then the tenon fiber cloth cut in step 3 is stacked and laid on the first curved concave surface until it is flush with the outermost blade body fiber cloth, and finally the remaining tenon fiber cloth is stacked and laid on the first curved convex surface to obtain a stacked upper mold (3) and a lower mold (4); Step 4.2, closing the laminated upper mold (3) and the lower mold (4), and fastening them with a fastening assembly (8) to obtain a shaped blade preform (22); Step 4.3, using a 0.15 mm feeler gauge to detect the gap between the finalized blade preform (22) and the upper mold (3) and the lower mold (4), if the gap is ≥ 0.15 mm, then proceed to step 4.4; if the gap is < 0.15 mm, then proceed to step 5; Step 4.4, disassemble the fastening assembly (8), add the re-cut blade body fiber cloth and tenon fiber cloth to the outermost blade body fiber cloth and tenon fiber cloth, and return to step 4.

2.

3. The method for preparing a ceramic matrix composite blade according to claim 2, characterized in that: In step 2, the diameters of the first sewing holes (9) and the second sewing holes (11) are both 3 to 5 mm, and the distances between adjacent first sewing holes (9) and adjacent second sewing holes (11) are both 5 to 8 mm; The mounting profile of the upper mold (3) and the mounting profile of the lower mold (4) are both profiles of equal wall thickness.

4. The method for preparing a ceramic matrix composite blade according to any one of claims 1 to 3, characterized in that: In step 3, the blade body fiber cloth and the tenon fiber cloth are cut to a size that reserves a 6-10 mm edge lock margin.

5. The method for preparing a ceramic matrix composite blade according to claim 4, characterized in that: Step 5 is as follows: The shaped blade preform (22) is sewn through and then edge-locked; the edge-locking needs to meet the following conditions: no needle fall-off, and the stitch gap is ≤3mm.

6. The method for preparing a ceramic matrix composite blade according to claim 5, characterized in that: Step 6 specifically includes the following steps: Step 6.1, placing the edge-locked blade preform (22) in a chemical vapor deposition furnace, and then heating it to 650-1000°C under a furnace pressure of 50-1000 Pa, keeping it warm for 1-3 hours, and then introducing argon, hydrogen, ammonia and boron trichloride gases in sequence for deposition until a blade preform (22) with a boron nitride interface layer with a thickness of 150-750 nm is obtained, and then keeping it warm for 1-3 hours, and then cooling it to room temperature; Alternatively, the edge-locked blade preform (22) is placed in a chemical vapor deposition furnace, and then the temperature is raised to 500-1000° C. at a pressure of 10-70 Pa in the furnace, and then argon gas and propylene gas are introduced in sequence for deposition after being kept at this temperature for 1-3 hours, until a blade preform (22) having a pyrolytic carbon interface layer with a thickness of 100-350 nm is obtained, and the temperature is kept at this temperature for another 1-3 hours, and then the temperature is lowered to room temperature; Step 6.2: Under the condition of a furnace pressure of 200-5000 Pa, the temperature is raised to 900-1200° C., and after keeping the temperature for 1-2 hours, a mixed gas of trichloromethylsilane, hydrogen and argon is introduced, and the flow ratio of trichloromethylsilane, hydrogen and argon is 1-10:10-12:10-30, and the blade preform (22) obtained in step 6.1 is deposited until a material having a carbon fiber thickness of 1.7-1.8 g / cm 3 The blade preform (22) with a high density silicon carbide matrix layer is kept warm for 1-3 hours and then cooled to room temperature.

7. The method for preparing a ceramic matrix composite blade according to claim 6, characterized in that: Step 7 is as follows: Remove the upper mold (3) and the lower mold (4), first perform mechanical processing on the blade preform (22) obtained in step 6.2, and then perform silicon carbide substrate deposition processing according to the deposition method in step 6.2 until the density of the silicon carbide substrate layer is greater than 2.4g / cm 3 , and obtain a ceramic matrix composite blade.

8. The method for preparing a ceramic matrix composite blade according to claim 2, characterized in that: In step 2, each of the fastening assemblies (8) comprises two pressure strips (6), two stud bolts (7) and four nuts (5); The two pressure strips (6) are used to abut against the opposite surface of the mounting profile of the upper mold (3) and the opposite surface of the mounting profile of the lower mold (4), respectively; The two stud bolts (7) are used to penetrate the two ends of the two pressure strips (6) respectively, and are fastened by four nuts (5).

9. The method for preparing a ceramic matrix composite blade according to claim 8, characterized in that: The material of the shaping mold is high temperature resistant material.

10. The method for preparing a ceramic matrix composite blade according to claim 9, characterized in that: The shaping die is made of high-strength fine graphite material, high-purity graphite material or electrode graphite material.

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