A method for manufacturing a ceramic matrix composite overhang part

Abstract

The present application relates to a kind of ceramic matrix composite hanging point part preparation method.Solve the existing hanging point class parts in the process of preform layering There are a large number of cutting ports, notches and wrinkles, resulting in poor continuity of carbon fiber cloth, graphite tooling mold does not reach the position, affect the performance of the technical problems of parts.The preparation method of the present application comprises the following steps:1) using simple tooling and graphite tooling mold, by cutting, layering, flanging and filling way to the first layer of fiber cloth is handled, obtain preform preliminary forming piece;According to the size of the part wall thickness, on the surface of preform preliminary forming piece Multiple layers of fiber cloth are stacked, fitted and laid to obtain the final preform;Wherein, each layer of fiber cloth is formed by splicing a plurality of small pieces of fiber cloth, and each small piece of fiber cloth is fitted on the corresponding part of the preform;The splicing positions of the plurality of small pieces of fiber cloth of two adjacent layers of fiber cloth are arranged in a staggered manner;2) shaping;3) deposition;4) processing to obtain the final part.

Description

Technical Field

[0001] This invention relates to a method for preparing ceramic matrix composite materials, specifically to a method for preparing a continuous fiber-reinforced ceramic matrix composite attachment point part for connecting a metal shaft and a rudder. Background Technology

[0002] Continuous fiber-reinforced ceramic matrix composites (CMCs) have become a major development direction in ceramic matrix composites due to their advantages such as low density, high toughness, high strength, high temperature resistance, thermal shock resistance, and non-catastrophic failure. Among them, CMC-SiC ceramic composites with SiC ceramic as the matrix have become a popular material in the aerospace field due to their superior performance in terms of high temperature limit, mechanical strength, oxidation resistance, and ablation resistance compared to other ceramic matrix composites. CMC-SiC ceramic matrix composites are now widely used as thermal protection materials for aircraft control surfaces and wings, significantly improving heat resistance while reducing product weight, effectively extending flight range and increasing flight speed.

[0003] With the gradual development of continuous fiber-reinforced ceramic matrix composite (CMC) manufacturing processes, in the structural design of components, to improve the overall mechanical properties of components and reduce assembly interfaces between parts, CMC components are gradually becoming more integrated, larger, and structurally more complex. Hook-type components, as supporting parts for connecting metal shafts and CMCs in rudder-type products, serve two main functions: firstly, connecting the metal shaft and the CMC; secondly, acting as a skin at the connection point, participating in thermal protection; and finally, acting as a thermal buffer between the metal shaft and the insulation material, solving the problem of thermal mismatch between the metal, the composite material, and the insulation material.

[0004] Currently available literature indicates that the types of parts whose preforms can be fabricated using two-dimensional carbon fiber layup include: flat plates, simple L&U-shaped parts, U-shaped beams, large-size skins, I-beams, box-shaped parts, U-shaped parts, cylindrical bodies, and irregularly shaped parts. The preforms of these parts are typically formed by slightly cutting and flanging a continuous piece of carbon fiber, or by laying carbon fiber in sections internally and continuously laying it on the outer layer. The flanging of these preforms is easy to handle, and the carbon fiber wrinkles at the corners of adjacent surfaces are not severe. However, hanging point parts typically contain at least three flanges in different directions, and all flanges are rounded edges. This inevitably results in numerous cutting cuts, gaps, and wrinkles during the layup process. Therefore, the continuity of the carbon fiber fabric in these preforms is significantly worse than that of other types of parts. Furthermore, during mold closing, wrinkles can cause the graphite tooling to fail to close properly, thus affecting the final performance of the part. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that existing hanging point parts contain at least three flanges in different directions, and all flanges are rounded edges. This results in a large number of cutting cuts, gaps and wrinkles during the layup of the prefabricated part, leading to poor continuity of carbon fiber cloth and incomplete mold closing of graphite tooling, thus affecting the final performance of the part. The invention provides a method for preparing ceramic matrix composite hanging point parts.

[0006] The technical solution of this invention is:

[0007] A method for preparing a ceramic matrix composite hanging point part, characterized by the following steps:

[0008] 1) Precast body forming

[0009] 1.1) Prepare a complete piece of fiber cloth, and cut it to obtain the first layer of fiber cloth according to the length and width dimensions of the outer surface of the part;

[0010] 1.2) Based on the external structure of the part, using simple tooling and graphite tooling molds, the first layer of fiber cloth is processed by cutting, laying, flanging and filling to obtain a pre-formed part with the same external structure as the part.

[0011] 1.3) Based on the wall thickness of the part, multiple layers of fiber cloth are laminated, bonded, and laid on the surface of the pre-formed part to obtain the final preform; wherein, each layer of fiber cloth is formed by splicing multiple small pieces of fiber cloth, and each small piece of fiber cloth is bonded to the corresponding part of the preform; the splicing positions of multiple small pieces of fiber cloth in two adjacent layers of fiber cloth are staggered to ensure the fiber continuity of the final preform;

[0012] 2) Shaping

[0013] The preform is shaped and compacted using graphite tooling molds;

[0014] 3) The preform is subjected to interface layer deposition and SiC substrate deposition in sequence to obtain the blank of the part;

[0015] 4) Processing

[0016] According to the final required dimensions and allowance of the part, the blank is rough machined using diamond cutting tools; according to the final dimensions and geometric tolerances of the part, it is finished. After machining, ultrasonic cleaning and drying are performed to obtain the final part.

[0017] Further, in step 1), the part includes an oblong left panel and a right panel, two parallel rectangular lugs, a downward-curving left arc plate located between the lower left edges of the two rectangular lugs, a downward-curving right arc plate located between the lower right edges of the two rectangular lugs, and an upward-curving middle arc plate located between the middle edges of the rectangular lugs; the notches of the rectangular lugs face downwards; the left panel is connected to the right edge of the left arc plate, the left edge of the notches of the two rectangular lugs, and the left edge of the middle arc plate; the right panel is connected to the left edge of the right arc plate, the right edge of the notches of the two rectangular lugs, and the right edge of the middle arc plate.

[0018] Further, in step 1.2), the simple tooling is a rectangular body that runs through the inside and outside along the length direction. An arched structure is provided at the upper end of the rectangular body, and the two ends of the arched structure are flush with the side edges of the rectangular body. The upper arc surface of the arched structure is adapted to the middle arc plate of the part, and the height and width of the two outer sides of the rectangular body are adapted to the size of the part.

[0019] In step 1.2), the graphite tooling mold includes an inner mold, an outer mold, and fastening components;

[0020] The outer mold includes two parallel vertical plates, a base plate, and a boss;

[0021] The two uprights and the base plate form a U-shaped structure with an opening at the top;

[0022] The boss has an elongated oval cross section, with its two sides connected to the front and rear uprights respectively. Its upper arc surface matches the middle arc plate, and its lower arc surface connects to the bottom plate. The left and right sides of the boss match the left and right panels respectively.

[0023] The lower half of the inner side of the two upright plates and the two front and rear connection points of the inner side of the base plate are both arc-shaped surfaces; the two arc-shaped surfaces are respectively matched with the left arc-shaped plate and the right arc-shaped plate;

[0024] The upper half of the inner side surface of the two uprights is respectively matched with two rectangular hanging ears;

[0025] The outer surface of the inner mold matches the inner surface of the outer mold, and a gap is provided between them to accommodate the parts.

[0026] The fastening assembly is used to fasten the inner and outer molds after they are closed, and to control the wall thickness of the parts.

[0027] Further, in step 1.2), the fastening assembly includes a first reinforcing frame and a second reinforcing frame; the first reinforcing frame and the second reinforcing frame are respectively sleeved on the periphery of the inner mold and the outer mold after they are closed, the inner side surface of the upper end of the first reinforcing frame and the second reinforcing frame are in contact with the upper end surface of the inner mold, and the inner side surface of the lower end of the first reinforcing frame and the second reinforcing frame are in contact with the lower end surface of the outer mold.

[0028] Furthermore, a limiting groove is provided on the upper end face of the inner mold along the height direction. After the mold is closed, the bottom of the limiting groove is flush with the upper end face of the outer mold, which is used to determine whether the mold is closed in place.

[0029] The upper end face of the inner mold is a draft surface that rises from low to high along the length direction, with an inclination angle of 1° to 5° from the low side to the high side.

[0030] The contact surfaces of the first and second reinforcing frames are adapted to the upper end surface of the inner mold. The first and second reinforcing frames are used to be inserted from the lower side and moved to the theoretical position for tightening and fixing. The theoretical position is calculated based on the wall thickness of the part.

[0031] Furthermore, the boss is provided with a hollow structure that runs through the inside and outside, with the opening facing downwards, located on the outer side of the outer mold and along the side and bottom surfaces of the boss;

[0032] The outer mold also includes an outer frame base. The inner surface of the outer frame base is adapted to the outer surface of the U-shaped structure. The outer edge of the U-shaped structure is attached to the corresponding position on the inner surface of the outer frame base, and the middle part of the bottom end of the U-shaped structure is suspended. The outer surface of the outer frame base is a right-angle structure.

[0033] The width of the limiting groove is 5~20mm and the depth is 5~20mm;

[0034] The inner mold is provided with reinforcing ribs at the upper corners that connect the front and rear side walls;

[0035] Limiting protrusions are provided on the outer wall of the outer mold at the positions of the first reinforcing frame and the second reinforcing frame.

[0036] Furthermore, the outer mold is a split splicing structure, formed by splicing two symmetrical half-structures, with the splicing line perpendicular to the left and right sides of the boss; detection reference holes are provided on the side of the splicing part of the half-structures, and the detection reference holes of the two half-structures are correspondingly set.

[0037] The bottom of the outer frame base is provided with reinforcing ribs.

[0038] Further, step 1.2) specifically involves:

[0039] 1.2.1) Place the first layer of fiber cloth on the simple tooling, ensuring that the center point of the first layer of fiber cloth coincides with the center point of the upper arc surface of the arch structure; fold the first layer of fiber cloth on both sides of the arch structure downwards, so that the first layer of fiber cloth on both sides is attached to the two outer surfaces of the simple tooling respectively, and ensure that there are no wrinkles at the right angle intersections when folding.

[0040] 1.2.2) Forming of the middle arc plate: Cut the suspended part in the folded right angle so that the middle part of the first layer of fiber cloth is attached to the upper arc surface of the simple tooling;

[0041] 1.2.3) Cut the first layer of fiber cloth on both sides: Cut the first layer of fiber cloth on the two outer sides of the simple tool along the arch structure, and make the upper edge flush with the edge of the arch structure after cutting; Fold the excess first layer of fiber cloth on the two outer sides of the rectangle perpendicular to the side of the simple tool to obtain four first folded edges.

[0042] Fold the excess first layer of fiber cloth at both ends of the middle arc plate upwards until it is perpendicular to the horizontal plane to obtain two second folded edges;

[0043] 1.2.4) Based on the lowest point positions of the left and right arc plates of the part, cut the lower part of the two first folded edges of each outer side respectively, and fold the first layer of fiber cloth attached to the lower part of the outer side of the simple tooling vertically upward along the cutting line to obtain the third folded edge of each outer side.

[0044] 1.2.5) Based on the shape and size of the left and right arc plates of the part, cut and trim the four first folded edges and the two third folded edges respectively. In accordance with the principle of minimizing cutting cuts, form two downward curved arc structures on the two outer sides of the simple tooling respectively. Ensure the continuity of the fiber cloth on the part during cutting and trimming.

[0045] 1.2.6) Remove the first layer of fiber cloth laid on the simple tooling and place it on the outer mold of the corresponding graphite tooling mold, so that the corresponding surfaces fit together smoothly; according to the structure of the rectangular hanging ears in the part, fill in the missing parts on both sides of the second folded edge to ensure the continuity of the fibers at the connection with the second folded edge, and obtain a pre-formed part with the same shape and structure as the part.

[0046] Furthermore, a calibration deposition step is included after roughing and before finishing:

[0047] SiC substrate deposition was performed on the rough-machined parts, with the process conditions being the same as in step 3.2);

[0048] It also includes step 5) decorative deposition: to improve the final surface uniformity of the part and to repair exposed fibers;

[0049] Step 3) includes the following steps:

[0050] 3.1) Interface layer deposition

[0051] The preform with graphite tooling mold is loaded into the furnace and an interface layer is deposited to achieve an interface layer thickness of 80-400nm. The preform is then removed from the furnace. The interface layer can be selected from pyrolytic carbon PyC, boron nitride BN, and PyC+BN composite interface layer, depending on the service conditions of the part.

[0052] 3.2) SiC substrate deposition

[0053] The burrs on the preform are removed, and SiC matrix deposition is performed on the preform to achieve a density of 1.3~2.5 g / cm³. 3 This yields the blank of the part.

[0054] Further, in step 1.1), the fiber cloth is C fiber cloth, SiC fiber cloth, or Al2O3 fiber cloth;

[0055] In step 3.1), the conditions for interface layer deposition are as follows: the vacuum degree in the furnace is evacuated to ≤20 Pa, heating is started, Ar2, propylene and N2 are introduced, and when the temperature reaches the range of 400~1200 ℃, the temperature is held for 30~150 h, and then the temperature is lowered to below 50 ℃ and the parts are taken out.

[0056] In step 3.2), the conditions for SiC substrate deposition are as follows: the vacuum degree is reduced to ≤1000 Pa, and silane is extracted, the temperature is increased, Ar2 is introduced, the temperature is maintained, H2 is introduced, and the temperature is decreased in sequence.

[0057] The beneficial effects of this invention are:

[0058] 1. The present invention provides a method for preparing a ceramic matrix composite hanging point part, and provides a preform layup method for hanging point parts with multiple arc surfaces and multiple flange directions, providing a preparation method for preform forming of ceramic matrix composite materials with multiple arc surfaces and multiple flange directions.

[0059] 2. The present invention provides a method for preparing ceramic matrix composite hanging point parts, and provides a graphite tooling for CVI-SiC deposition of hanging point parts with multiple arc surfaces and multiple flange directions and its usage method, which ensures that complex-shaped hanging point parts can be deposited in a high-temperature vacuum atmosphere furnace.

[0060] 3. The present invention provides a method for preparing ceramic matrix composite hanging point parts, and provides a simple tooling for laying up hanging point parts with multiple arc surfaces and multiple flange directions. It is simple, convenient and efficient to use. Attached Figure Description

[0061] Figure 1 This is a front view of a ceramic matrix composite hanging point part;

[0062] Figure 2 This is a left view of a ceramic matrix composite hanging point part;

[0063] Figure 3 This is a right view of a ceramic matrix composite hanging point part;

[0064] Figure 4 This is a schematic diagram of a simplified tooling structure in an embodiment of a method for preparing a ceramic matrix composite hanging point part according to the present invention;

[0065] Figure 5 This is a schematic diagram of one half of the outer mold of the graphite tooling mold in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0066] Figure 6 This is a schematic diagram of another half of the graphite tooling mold in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0067] Figure 7 This is a schematic diagram of the structure of the inner mold of the graphite tooling mold in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0068] Figure 8 This is a schematic diagram of the assembly of the preform and the outer mold of the graphite tooling mold in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention.

[0069] Figure 9 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 1 ;

[0070] Figure 10 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 2 ;

[0071] Figure 11 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 3 ;

[0072] Figure 12 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 4 ;

[0073] Figure 13 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 5 ;

[0074] Figure 14 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 6 ;

[0075] Figure 15 This is an example of the preform forming process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention. Figure 7 ;

[0076] Figure 16 This is a schematic diagram of the second layer fiber cloth layup process in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention;

[0077] Figure 17 This is a schematic diagram of the second layer fiber cloth layup process in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0078] Figure 18 This is a diagram showing the completion of the second layer of fiber cloth after laying in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention;

[0079] Figure 19 This is a schematic diagram of the third layer fiber cloth layup process in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0080] Figure 20 This is a schematic diagram of the third layer fiber cloth layup process in an embodiment of the method for preparing a ceramic matrix composite hanging point part of the present invention;

[0081] Figure 21 This is a finalized illustration of an embodiment of the preparation method of a ceramic matrix composite hanging point part according to the present invention;

[0082] Figure 22 This is an assembly diagram of graphite shaping tooling and parts in an embodiment of the preparation method of a ceramic matrix composite hanging point part of the present invention;

[0083] Figure 23 This is a schematic diagram of the graphite alignment tooling in an embodiment of the method for preparing a ceramic matrix composite hanging point part according to the present invention.

[0084] Reference numerals: 1-Part, 11-Left panel, 12-Right panel, 13-Rectangular lug, 14-Left curved plate, 15-Right curved plate, 16-Middle curved plate; 2-Simple tooling, 21-Arch structure; 3-Graphite tooling mold, 31-Outer mold, 311-Boss, 312-U-shaped structure, 313-Outer frame base, 314-Limiting protrusion, 315-Inspection reference hole, 316-Reinforcement Rib; 32-Inner mold, 321-Limiting groove, 322-Reinforcing rib; 33-Fastening component, 8-First reinforcing frame, 9-Second reinforcing frame; 4-First layer of fiber cloth; 41-First folded edge, 42-Second folded edge, 43-Third folded edge, 44-Second layer of rectangular hanging ear carbon cloth, 45-Second layer of left panel carbon cloth, 46-Third layer of carbon cloth; 10-Correction tooling base, 11-Clamping plate, 12-Inner support plate. Detailed Implementation

[0085] This application first describes a prefabrication layup method for complex-shaped hanging point parts with multiple flange directions and arc-shaped flanges, and the usage of a simple tooling 2 and a graphite tooling mold 3 during the prefabrication layup process. With accompanying drawings, it details the cutting position of a single layer of carbon cloth within a unit thickness, the gap filling method, and the misalignment method of the cutting edges of adjacent carbon cloths. Subsequently, a graphite tooling mold 3 and a simple tooling 2 are designed for use in the CVI-SiC deposition process of this type of part, and the structural form of each part of the tooling and its usage method are described. Finally, to prevent deformation of the hanging point parts during high-temperature deposition, an anti-deformation tooling is designed, and the structure of each part of the tooling and its usage method during the deposition process are described with reference to the accompanying drawings.

[0086] The shape of the mounting point component resembles the crankshaft in an engine. The simplest mounting point component typically includes one central arc surface and two side arc surfaces with concave and convex directions opposite to the central arc surface. The layup of the mounting point component preform described in this article begins with the flanging of the two sides of the central arc surface. In this embodiment, the structure of the ceramic matrix composite mounting point component 1 is as follows: Figures 1-3 As shown, part 1 includes an oblong left panel 11 and a right panel 12, two parallel rectangular lugs 13, a left curved plate 14 located between the lower left edges of the two rectangular lugs 13 and curving downwards, a right curved plate 15 located between the lower right edges of the two rectangular lugs 13 and curving downwards, and a middle curved plate 16 located between the middle edges of the rectangular lugs 13 and curving upwards; the notches of the rectangular lugs 13 face downwards; the left panel 11 is connected to the right edge of the left curved plate 14, the left edge of the notches of the two rectangular lugs 13, and the left edge of the middle curved plate 16; the right panel 12 is connected to the left edge of the right curved plate 15, the right edge of the notches of the two rectangular lugs 13, and the right edge of the middle curved plate 16.

[0087] The structure of the simplified tooling 2 in this embodiment is as follows: Figure 4As shown, the simple tooling 2 is a rectangular body that runs through the inside and outside along the length direction. An arched structure 21 is set at the upper end of the rectangular body. The two ends of the arched structure are flush with the side edges of the rectangular body. The upper arc surface of the arched structure is adapted to the middle arc plate 16 of part 1. The height and width of the two outer sides of the rectangular body are adapted to the size of part 1.

[0088] In this embodiment, the graphite tooling mold 3 is as follows: Figures 5-7 As shown, it includes an inner mold 32, an outer mold 31, and a fastening assembly 33. The outer mold 31 includes two parallel upright plates, a base plate, and a boss 311; the two upright plates and the base plate form a U-shaped structure 312 with an upper opening; the boss 311 has an elongated oval cross section, with its two sides connected to the two upright plates respectively, its upper arc surface matching the middle arc plate 16, and its lower arc surface connecting to the base plate; the left and right sides of the boss 311 match the left panel 11 and the right panel 12 respectively; the lower half of the inner side of the two upright plates and the two connecting points of the inner side of the base plate are both arc surfaces; the two arc surfaces match the left arc plate 14 and the right arc plate 15 respectively; the upper half of the inner side of the two upright plates matches the two rectangular lugs 13 respectively; the outer surface of the inner mold 32 matches the inner surface of the outer mold 31, and a gap is provided between them to accommodate part 1. The inner mold 32 has reinforcing ribs 322 at its upper corners, connecting the front and rear sidewalls, which enhances the overall strength of the inner mold 32. The boss 311 has a hollow structure that extends through both the inner and outer sides, with the opening facing downwards. It is located on the outer side of the outer mold 31 and runs along the side and bottom surfaces of the boss 311, providing ventilation during the deposition process. To better fix the preform during deposition and to achieve better adhesion between carbon cloth layers during SiC matrix deposition, the preform is sewn onto the outer mold 31 using carbon fiber bundles. The carbon fiber bundles are 1K to 12K, and the spacing between the sewn holes ranges from 5 to 20 mm. This can be adjusted by varying the hole spacing and the parameters of the sewn fiber bundles according to the final performance requirements of the part.

[0089] To facilitate fixing and placement, the outer mold 31 is provided with an outer frame base 313. The inner surface of the outer frame base 313 is adapted to the outer surface of the U-shaped structure 312. The outer edge of the U-shaped structure 312 is attached to the corresponding position on the inner surface of the outer frame base 313, and the middle part of the bottom end of the U-shaped structure 312 is suspended. The outer surface of the outer frame base 313 is a right-angle structure. In this embodiment, the outer frame base 313 and the U-shaped structure 312 are integrally molded parts, and the bottom of the outer frame base 313 is provided with reinforcing ribs 316 to enhance the strength and rigidity of the outer mold.

[0090] For ease of processing, the outer mold 31 can be designed as a split splicing structure, formed by splicing two symmetrical half-structures together using a special adhesive. The splicing line is perpendicular to the left and right sides of the boss 311. Detection reference holes 315 are provided on the side of the splicing part of the half-structures, and the detection reference holes 315 of the two half-structures are set accordingly.

[0091] The fastening assembly 33 is used to fasten the inner mold 32 and the outer mold 31 after mold closing, and to control the wall thickness of part 1. The fastening assembly 33 includes a first reinforcing frame 8 and a second reinforcing frame 9; the first reinforcing frame 8 and the second reinforcing frame 9 are respectively fitted around the outer periphery of the inner mold 32 and the outer mold 31 after mold closing. The inner side surfaces of the upper ends of the first reinforcing frame 8 and the second reinforcing frame 9 are in contact with the upper end surface of the inner mold 32, and the inner side surfaces of the lower ends of the first reinforcing frame 8 and the second reinforcing frame 9 are in contact with the lower end surface of the outer mold 31. A limiting groove 321 is provided on the upper end surface of the inner mold 32 along the height direction. After mold closing, the bottom of the limiting groove 321 is flush with the upper end surface of the outer mold 31, which is used to determine whether the mold closing is in place. The width of the limiting groove 321 is 5~20mm and the depth is 5~20mm. The upper surface of the inner mold 32 is a draft surface that rises from low to high along its length, with an inclination angle of 1° to 5° from the low side to the high side. The contact surfaces of the first reinforcing frame 8 and the second reinforcing frame 9 are adapted to the upper surface of the inner mold 32. The first reinforcing frame 8 and the second reinforcing frame 9 are used to fit into each other from the low side and move to the theoretical position for tightening and fixing. The theoretical position is calculated based on the wall thickness of part 1. Limiting protrusions 314 are also provided on the outer side wall of the outer mold 31 at the positions of the first reinforcing frame 8 and the second reinforcing frame 9, which allows the first reinforcing frame 8 and the second reinforcing frame 9 to move quickly to the theoretical position.

[0092] Using the aforementioned simple tooling 2 and graphite tooling mold 3, the ceramic matrix composite hanging point part 1 is prepared by the method of the present invention, comprising the following steps:

[0093] 1) Precast body forming

[0094] 1.1) Extract the outer surface of part 1 using software and unfold it to obtain the length and width dimensions of the unfolded area. Prepare a complete piece of fiber cloth and then use a fully automatic cutting machine to cut it to obtain the first layer of fiber cloth 4. The fiber cloth can be C fiber cloth (carbon cloth), SiC fiber cloth, or Al2O3 fiber cloth. In this embodiment, carbon cloth is used.

[0095] 1.2) Based on the external structure of part 1, using simple tooling 2 and graphite tooling mold 3, the first layer of fiber cloth 4 is processed through cutting, layering, flanging, and filling to obtain a preliminary prefabricated part with the same external structure as part 1. The specific steps are as follows:

[0096] 1.2.1) Place the first layer of fiber cloth 4 on the simple tooling 2, ensuring that the center point of the first layer of fiber cloth 4 coincides with the center point of the upper arc surface of the arched structure 21, see [reference]. Figure 9 Fold the first layer of fiber cloth 4 on both sides of the arched structure 21 downwards, so that the first layer of fiber cloth on both sides is attached to the two outer surfaces of the simple tool. When folding, ensure that there are no wrinkles at the right angle intersections. See Figure 10 To facilitate subsequent hemming and cutting operations, the carbon fiber fabric on both sides can be temporarily fixed by clamping, using adhesive tape, or sewing fiber bundles together.

[0097] 1.2.2) Forming of the middle arc-shaped plate 16: The suspended part in the folded right angle is cut off so that the middle part of the first layer of fiber cloth 4 is attached to the upper arc surface of the simple tooling 2, see [reference]. Figure 11 To ensure the integrity of the fiber cloth coverage area at the 16 points of the central arc plate, the cutting line must be aligned with the two outer planes of the simple tooling 2 during cutting. The areas with cutting lines in the figure are the cutting areas (one at each of the four right angles, for a total of four). The carbon cloth in the cutting areas needs to be removed during subsequent folding and cutting.

[0098] 1.2.3) Cutting the first layer of fiber cloth 4 on both sides: Cut the first layer of fiber cloth 4 on the two outer sides of the simple tooling 2 along the arched structure 21, making the upper edge flush with the edge of the arched structure 21; Fold the excess first layer of fiber cloth 4 on the two outer sides of the rectangular body perpendicular to the side of the simple tooling 2 to obtain four first folded edges 41; Fold the excess first layer of fiber cloth 4 at both ends of the middle arc plate 16 upwards to be perpendicular to the horizontal plane to obtain two second folded edges 42; See Figure 12 After folding, all right-angled sides and both ends of the middle arc plate 16 should be completely aligned with the corresponding positions of the graphite tooling outer mold.

[0099] 1.2.4) Based on the lowest point positions of the left arc-shaped plate 14 and the right arc-shaped plate 15 of part 1, the lower parts of the two first folded edges 41 on each outer side are cut off. See the cutting positions for details. Figure 13 Fold the first layer of fiber cloth 4, which is attached to the lower part of the outer side of the simple tool 2, vertically upward along the cutting line to obtain the third folded edge 43 of each outer side.

[0100] 1.2.5) Based on the external structure and dimensions of the left arc plate 14 and right arc plate 15 of part 1, the four first folded edges 41 and the two third folded edges 43, as well as the surrounding carbon cloth, are cut and trimmed to ensure that the carbon cloth at the side arc plates is free of wrinkles and air pockets. Following the principle of minimizing cuts, the continuity of the carbon cloth on the part is ensured. The folded edges at the arc surfaces will have wrinkles distributed along the arc line and cuts distributed along the arc surface. See [reference needed]. Figure 14 First of all Figure 13The carbon fiber cloth in the cutting area shown is cut off. Then, according to the requirements of folding and layering, the carbon fiber cloth on the arc surface is cut off, and the overlapping area of ​​carbon fiber cloth is removed. After cutting, two downward curved arc structures are formed on the two outer sides of the simple tooling 2. During cutting and trimming, the continuity of the fiber cloth on the part is ensured.

[0101] 1.2.6) Remove the first layer of fiber cloth 4 laid on the simple tooling 2 and place it on the outer mold 31 of the corresponding graphite tooling mold 3, ensuring that the corresponding surfaces are flat and aligned. Temporarily fix the fiber cloth using clamps, adhesives, or fiber bundle sewing. Then, neatly trim the carbon cloth at the top arc ends on both sides. Based on the structure of the rectangular lug 13 in part 1, fill in the missing parts on both sides of the second folded edge 42, ensuring the continuity of fibers at the connection with the second folded edge 42, to obtain a preliminary preform with the same external structure as part 1. The temporarily filled carbon cloth is bonded with polymer resin adhesive. The first layer of preform after filling with carbon cloth is as follows: Figure 15 As shown, the layup of the first layer of carbon cloth and the graphite tooling mold outer mold 31 used in the actual layup process is as follows: Figure 8 As shown.

[0102] 1.3) Based on the wall thickness of part 1, multiple layers of fiber cloth are laminated, bonded and laid on the surface of the pre-formed part to obtain the final preform; wherein, each layer of fiber cloth is formed by splicing multiple small pieces of fiber cloth, and each small piece of fiber cloth is bonded to the corresponding part of the preform; the splicing positions of multiple small pieces of fiber cloth in two adjacent layers of fiber cloth are staggered to ensure the fiber continuity of the final preform.

[0103] 1.3.1) To avoid overlapping cut edges of adjacent or nearby carbon fiber layers, which could cause a sharp decrease in the mechanical strength of the hanging part near a certain cut edge, the carbon fiber layup process must employ cut edge misalignment to achieve near-continuous carbon fiber throughout the entire part's thickness, thereby ensuring the part's mechanical properties. As seen in step 1.2), the four right angles of the first layer of carbon fiber are filled with additional carbon fiber, resulting in discontinuity. Therefore, the second layer of carbon fiber compensates for this discontinuity by designing the carbon fiber at the middle arc plate 16 and its two end flanges as continuous. The cutting lines and the shape after the layup are shown in [reference needed]. Figure 16 .

[0104] 1.3.2) The curved surfaces and side flanges of the second layer of carbon cloth are composed of two separate parts. The cutting and folding methods of the curved surfaces are the same as those of the first layer of carbon cloth. The difference is that the cutting edges should be staggered from those of the first layer. See the carbon cloth for the left panel 11, right panel 12, left curved plate 14, and right curved plate 15 of the second layer. Figure 17 As shown.

[0105] 1.3.3) Lay the cut second layer of carbon fiber onto the corresponding position of the first layer of carbon fiber. During the laying process, ensure that it does not affect the connection between the first layer of carbon fiber and the graphite tooling outer mold 31. During the laying process, ensure that there are no air pockets or wrinkles between adjacent carbon fibers. The carbon fibers are connected by bonding with polymer resin adhesive or by sewing fiber bundles. The second layer of rectangular hanging ear carbon fiber 44, the second layer of left panel carbon fiber 45, and other prefabricated bodies after the second layer of carbon fiber are laid are as follows: Figure 18 As shown. The second layer of carbon cloth ensures the continuity of the carbon cloth in the side arc plate and the adjacent flange area, while also ensuring the continuity of the carbon cloth in the four right-angle missing corner areas of the first layer of carbon cloth.

[0106] 1.3.4) Both the first and second layers of carbon fiber have cutting notches at the left curved plate 14 and the right curved plate 15. The third layer of carbon fiber requires the upper part of the notch in the middle curved plate 16, the rectangular hanging lug 13, the left panel 11, and the right panel 12 to be cut into a single piece. To achieve the curved surface of the middle curved plate 16, a cutting notch needs to be made on each of the two sides, and excess carbon fiber needs to be cut off. See [link to relevant documentation]. Figure 19 .

[0107] 1.3.5) The first two layers of carbon fiber have cutouts at the left curved plate 14 and the right curved plate 15. Furthermore, to achieve the layup of the curved surface, excess carbon fiber at the folds was trimmed. Therefore, the carbon fiber at the left curved plate 14 and the right curved plate 15 in the first two layers is discontinuous, and its strength cannot be guaranteed. The third layer of carbon fiber uses two continuous pieces of carbon fiber laid up at the left curved plate 14 and the right curved plate 15.

[0108] The cut carbon cloth is laid in the same manner as the first two layers. After the third layer of carbon cloth is laid, the preform is as follows: Figure 20 As shown.

[0109] When preparing continuous fiber-reinforced ceramic matrix composite parts using a layup method, the number of carbon cloth layers required for the layup is determined by dividing the part wall thickness by the thickness of a single carbon cloth layer. In this paper, the part wall thickness ranges from 1.5 to 5 mm, and the thickness of a single carbon cloth layer ranges from 0.15 to 0.17 mm. Therefore, during the layup process of the part preform, it is necessary to continuously adjust the cutting position and cutting method of each carbon cloth layer to ensure the fiber continuity of the final part preform.

[0110] The cutting method of the three-layer carbon cloth mentioned above is only an example and is not intended to limit the technology of this patent. The cutting methods involved in this article include cutting at any position and any carbon cloth distribution form that can be used while ensuring the mechanical strength of hanging point parts.

[0111] 2) Shaping

[0112] The inner mold 32 is closed with the outer mold 31 from top to bottom. During the mold closing process, care must be taken to avoid the graphite tooling mold 3 from tearing the fiber cloth. The left and right end faces of the inner mold 32 are aligned with the left and right end faces of the outer mold 31. To prevent cracking at the bonding surface of the outer mold during the mold closing process, clamps are used to temporarily tighten and reinforce the left and right ends of the outer mold 31. After the mold is closed, the first reinforcing frame 8 and the second reinforcing frame 9 are installed in sequence. The top surface of the inner mold 32 is the draft surface. Figure 21 As shown, the profile gradually rises from right to left. The planes on the first reinforcing frame 8 and the second reinforcing frame 9 that contact it are also draft surfaces. Therefore, during the installation of the reinforcing frames from right to left, the inner mold 32 and the outer mold 31 can be clamped together. At the same time, the upper end of the inner mold 32 is designed with a limit groove 321, which is used to indirectly determine whether the inner mold 32 is in the correct mold-closing position. Practical operation shows that controlling the mold-closing of the inner mold 32 and the outer mold 31 using this method cannot accurately control the wall thickness of part 1 in the mold-closing direction of the graphite tooling mold 3.

[0113] The position of the fastening component 33 determines the wall thickness of part 1, so as to Figure 21 Taking the graphite tooling mold 3 as an example, the draft surface gradually increases from right to left. When the reinforcing frame is on the right side of the theoretical position, the wall thickness of part 1 is too thick; when the reinforcing frame is on the left side of the theoretical position, the wall thickness of part 1 is too thin. Therefore, limiting the position of the reinforcing frame can effectively control the wall thickness of part 1. In this work, a limiting protrusion 314 is designed on the outer side of the outer mold 31 to limit the travel position of the reinforcing frame. The position and height of the limiting protrusion 314 need to be determined according to the size of the mold. Usually, the limiting protrusion 314 is set in front of the reinforcing frame in the forward direction. The height of the limiting protrusion 314 is generally 1~10 mm. In addition, by setting the limiting protrusion 314 on the bottom surface, side surface of the outer mold 31, and top surface of the inner mold 32, the position of the reinforcing frame can also be limited, thereby accurately controlling the wall thickness of part 1 in the mold closing direction.

[0114] 3) Sedimentation

[0115] Continuous fiber-reinforced SiC ceramic matrix composites mainly consist of three parts: fibers, interface layers, and the SiC matrix. The interface layer serves to connect the fibers and the SiC matrix. Appropriate interface layer type and thickness can effectively improve the toughness and strength of continuous fiber-reinforced SiC ceramic matrix composites. The fibers include C fibers, SiC fibers, Al2O3 fibers, etc., and the interface layers include pyrolytic carbon (PyC) interface layers, boron nitride (BN) interface layers, and composite (PyC+BN) interface layers. After the preform layering is completed and the graphite tooling mold is closed, the interface layer needs to be prepared.

[0116] 3.1) Interface layer deposition

[0117] The preform with graphite tooling mold 3 is placed in the middle region of the vapor phase infiltration interface layer deposition furnace and the interface layer is deposited to achieve an interface layer thickness of 80-400nm. The preform is then removed from the furnace. The interface layer can be selected from pyrolytic carbon PyC, boron nitride BN, and PyC+BN composite interface layer, depending on the service conditions of the part.

[0118] The conditions for interface layer deposition are as follows: the vacuum degree in the furnace is evacuated to ≤20 Pa, heating is started, Ar2, propylene and N2 are introduced, and when the temperature reaches the range of 400~1200 ℃, the temperature is held for 30~150 h, and then the temperature is lowered to below 50 ℃ and the parts are taken out.

[0119] 3.2) SiC substrate deposition

[0120] After removing the burrs from the preform (the preform locking area), first remove the inner mold 32, and then place the part 1 with the outer mold 31 into the SiC substrate deposition furnace to deposit SiC substrate on the preform until its density reaches 1.3~2.5 g / cm³. 3 Thus, the blank of part 1 is obtained.

[0121] The conditions for SiC substrate deposition are as follows: vacuum level ≤1000 Pa, followed by silane extraction, heating, Ar2 induction, heat preservation, H2 induction, and cooling. Due to the low efficiency of CVI-SiC deposition process, repeated deposition is currently used to gradually increase the density of the parts. During CVI-SiC deposition, gas molecules diffuse freely through open channels in the preform and deposit SiC in situ on the fiber surface. This deposition method inevitably leads to the densification of the surface preform first, and the inlet size of the deposition channel gradually decreases as the deposition process progresses. This results in a density gradient in the thickness direction of part 1. To ensure the consistency of the final part density in the thickness direction, after each deposition cycle, the part surface needs to be polished, ultrasonically cleaned, and dried. The porosity before each cycle is also measured and recorded. The total number of deposition cycles is 3 to 12.

[0122] 4) Processing

[0123] 4.1) According to the final required dimensions and allowance of part 1, and based on the process requirements, the blank outer dimensions are rough machined using diamond cutting tools. The wall thickness direction is not machined. During the machining process, in order to facilitate the positioning of the part, a machining fixture with a structure similar to a graphite tooling mold is used for auxiliary positioning and part fixation.

[0124] 4.2) Performing calibration deposition: In order to prevent the parts from deforming during the deposition process after machining, which would affect the subsequent assembly process, SiC substrate deposition is performed on the rough-machined parts 1. The process conditions are the same as in step 3.2).

[0125] Graphite calibration fixtures, see Figure 22 The graphite alignment fixture consists of three parts: a alignment fixture base 10, a clamping plate 11, and an inner support plate 12. The alignment fixture base 10 is structurally similar to the outer mold 31 of a graphite fixture mold in the deposition process. Its structure includes two vertically arranged bosses on the base that conform to the shape of part 1, primarily used to prevent the sides of part 1 from opening. The flanges on the left and right sides of the graphite alignment fixture are mainly used to prevent deformation of the arc surfaces and connecting surfaces on both sides of part 1. Figure 22 As shown, the graphite shaping fixture has serrated notches on the surface that contacts part 1, and a rectangular groove is provided in the middle area of ​​the base 10 of the shaping fixture to allow airflow during the deposition process, while also reducing the area of ​​the graphite shaping fixture covering the surface of part 1.

[0126] The state of Part 1 after assembly with the graphite alignment fixture is shown below. Figure 23 After rough machining, the part 1 is fitted to the corresponding surface on the calibration fixture base 10, ensuring a fitting gap of <0.1 mm. The clamping plates 11 are installed at the left and right ends of the graphite calibration fixture, ensuring that the gap between the inner surface of part 1 and the corresponding surface of the calibration fixture base 10 is ≤0.1 mm after the clamping plates 11 are installed. The inner support plate 12 is installed in the gap between the large planes on the left and right sides of part 1, and the inner support plate 12 must be perpendicular to the left and right sides. After installation, the part is deposited in the furnace using the same deposition process as the SiC substrate deposition process.

[0127] 4.3) According to the final part's external dimensions and geometric tolerances, the part is precision machined. During the precision machining process, tooling is also required for auxiliary positioning and fastening. After machining, ultrasonic cleaning and drying are performed to obtain the final part.

[0128] Step 5) Decorative deposition: Refine the final part surface consistency and repair exposed fibers.

Claims

1. A method for preparing a ceramic matrix composite hanging point part, characterized in that, Includes the following steps: 1) Precast body forming 1.1) Prepare a complete piece of fiber cloth, and cut the first layer of fiber cloth (4) according to the length and width dimensions of the outer surface of the part (1); the part (1) includes an oblong left panel (11) and a right panel (12), two rectangular hanging ears (13) arranged in parallel front and back, a left arc plate (14) located between the lower left edges of the two rectangular hanging ears (13) and bent downwards, a right arc plate (15) located between the lower right edges of the two rectangular hanging ears (13) and bent downwards, and a rectangular arc plate (16) located between the lower right edges of the two rectangular hanging ears (13) and bent downwards. A middle arc plate (16) with an upward curve between the middle edges of the hanging ears (13); the notch of the rectangular hanging ears (13) faces downward; the left panel (11) is connected to the right edge of the left arc plate (14), the left edge of the notch of the front and rear rectangular hanging ears (13), and the left edge of the middle arc plate (16); the right panel (12) is connected to the left edge of the right arc plate (15), the right edge of the notch of the front and rear rectangular hanging ears (13), and the right edge of the middle arc plate (16); 1.2) Based on the external structure of part (1), the first layer of fiber cloth (4) is processed by cutting, layering, flanging and filling through simple tooling (2) and graphite tooling mold (3) to obtain a pre-formed part with the same external structure as part (1); the simple tooling (2) is a rectangular body that runs through the inside and outside along the length direction, and an arch structure (21) is set at the upper end of the rectangular body. The two ends of the arch structure are flush with the side of the rectangular body; the upper arc surface of the arch structure is adapted to the middle arc plate (16) of part (1), and the height and width of the two outer sides of the rectangular body are adapted to the size of part (1); the graphite tooling mold (3) includes an inner mold (32), an outer mold (31) and a fastening component (33); the outer mold (31) includes two parallel upright plates, a bottom plate and a boss (311); the two upright plates and the bottom plate form a U-shaped opening at the top. The structure is shaped (312); the cross section of the boss (311) is oblong, its two sides are connected to the front and rear upright plates respectively, its upper arc surface matches the middle arc plate (16), and its lower arc surface is connected to the bottom plate; the left and right sides of the boss (311) match the left panel (11) and the right panel (12) respectively; the lower half of the inner side of the two upright plates and the front and rear connection points of the inner side of the bottom plate are both arc surfaces; the two arc surfaces match the left arc plate (14) and the right arc plate (15) respectively; the upper half of the inner side of the two upright plates matches the two rectangular hanging ears (13) respectively; the outer surface of the inner mold (32) matches the inner surface of the outer mold (31), and a gap is provided between them to accommodate the part (1); the fastening assembly (33) is used to fasten the inner mold (32) and the outer mold (31) after they are closed, and to control the wall thickness of the part (1); 1.3) Based on the wall thickness of part (1), multiple layers of fiber cloth are stacked, bonded and laid on the surface of the pre-formed part to obtain the final preform; wherein, each layer of fiber cloth is formed by splicing multiple small pieces of fiber cloth, and each small piece of fiber cloth is bonded to the corresponding part of the preform; the splicing positions of multiple small pieces of fiber cloth in two adjacent layers of fiber cloth are staggered to ensure the fiber continuity of the final preform; 2) Shaping The preform was shaped and compacted using a graphite tooling mold (3); 3) The preform is subjected to interface layer deposition and SiC substrate deposition in sequence to obtain the blank of part (1); 4) Processing According to the final required dimensions and allowance of part (1), the blank is rough machined using diamond cutting tools; according to the final part dimensions and geometric tolerances, it is fine machined; after machining, ultrasonic cleaning and drying are performed to obtain the final part.

2. The method for preparing a ceramic matrix composite hanging point part according to claim 1, characterized in that: In step 1.2), the fastening assembly (33) includes a first reinforcing frame (8) and a second reinforcing frame (9); the first reinforcing frame (8) and the second reinforcing frame (9) are respectively fitted around the outer periphery of the inner mold (32) and the outer mold (31) after they are closed; the inner side surface of the upper end of the first reinforcing frame (8) and the second reinforcing frame (9) contacts the upper end surface of the inner mold (32); and the inner side surface of the lower end of the first reinforcing frame (8) and the second reinforcing frame (9) contacts the lower end surface of the outer mold (31).

3. The method for preparing a ceramic matrix composite hanging point part according to claim 2, characterized in that: The upper end face of the inner mold (32) is provided with a limiting groove (321) along the height direction. After the mold is closed, the bottom of the limiting groove (321) is flush with the upper end face of the outer mold (31) to determine whether the mold is closed in place. The upper end face of the inner mold (32) is a draft surface that rises from low to high along the length direction, with an inclination angle of 1° to 5° from the low side to the high side; The contact surfaces of the first reinforcing frame (8) and the second reinforcing frame (9) are adapted to the upper end surface of the inner mold (32). The first reinforcing frame (8) and the second reinforcing frame (9) are respectively fitted from the lower side and moved to the theoretical position for tightening and fixing. The theoretical position is calculated based on the wall thickness of the part (1).

4. The method for preparing a ceramic matrix composite hanging point part according to claim 3, characterized in that: The boss (311) is provided with a hollow structure that runs through the inside and outside, with the opening facing downwards. It is located on the outer side of the outer mold (31) and is provided along the side and bottom of the boss (311). The outer mold (31) also includes an outer frame base (313), the inner surface of the outer frame base (313) is adapted to the outer surface of the U-shaped structure (312), the outer edge of the U-shaped structure (312) is attached to the corresponding position of the inner surface of the outer frame base (313), and the middle part of the bottom end of the U-shaped structure (312) is suspended; the outer surface of the outer frame base (313) is a right-angle structure; The width of the limiting groove (321) is 5~20mm and the depth is 5~20mm; The inner mold (32) is provided with reinforcing ribs (322) at the upper corners to connect the front and rear side walls. Limiting protrusions (314) are provided on the outer side wall of the outer mold (31) at the positions of the first reinforcing frame (8) and the second reinforcing frame (9).

5. The method for preparing a ceramic matrix composite hanging point part according to claim 4, characterized in that: The outer mold (31) is a split splicing structure, which is formed by splicing two symmetrical half-structures. The splicing line is perpendicular to the left and right sides of the boss (311). The side of the splicing part of the half-structure is provided with a detection reference hole (315), and the detection reference holes (315) of the two half-structures are set accordingly. The bottom of the outer frame base (313) is provided with reinforcing ribs (316).

6. The method for preparing a ceramic matrix composite hanging point part according to claim 5, characterized in that: Step 1.2) specifically refers to: 1.2.1) Place the first layer of fiber cloth (4) on the simple tool (2) and ensure that the center point of the first layer of fiber cloth (4) coincides with the center point of the upper arc surface of the arch structure (21); fold the first layer of fiber cloth (4) on both sides of the arch structure (21) downwards so that the first layer of fiber cloth on both sides is attached to the two outer surfaces of the simple tool, and ensure that there are no wrinkles at the right angle intersection when folding. 1.2.2) Forming of the middle arc plate (16): Cut the suspended part in the folded right angle so that the middle part of the first layer of fiber cloth (4) is attached to the upper arc surface of the simple tool (2); 1.2.3) Cut the first layer of fiber cloth (4) on both sides: Cut the first layer of fiber cloth (4) on the two outer sides of the simple tool (2) along the arch structure (21), and make the upper edge flush with the edge of the arch structure (21) after cutting; Fold the excess first layer of fiber cloth (4) on the two outer sides of the rectangle perpendicular to the side of the simple tool to obtain four first folded edges (41). Fold the excess first layer of fiber cloth (4) at both ends of the middle arc plate (16) upwards until it is perpendicular to the horizontal plane to obtain two second folded edges (42). 1.2.4) Based on the lowest point position of the left arc plate (14) and right arc plate (15) of part (1), cut the lower part of the two first folded edges (41) of each outer side respectively, and fold the first layer of fiber cloth (4) attached to the lower part of the outer side of the simple tooling (2) vertically upward along the cutting line to obtain the third folded edge (43) of each outer side. 1.2.5) Based on the shape and size of the left arc plate (14) and right arc plate (15) of part (1), cut and trim the four first folded edges (41) and the two third folded edges (43) respectively. In accordance with the principle of minimum cutting, two downward curved arc structures are formed on the two outer sides of the simple tooling (2). During cutting and trimming, ensure the continuity of the fiber cloth on the part. 1.2.6) Remove the first layer of fiber cloth (4) laid on the simple tooling (2) and place it on the outer mold (31) of the corresponding graphite tooling mold (3) so that the corresponding surfaces are flat and aligned; according to the structure of the rectangular hanging ear (13) in the part (1), fill in the missing parts on both sides of the second folded edge (42) to ensure the continuity of the fibers at the connection with the second folded edge (42) and obtain a preformed part with the same external structure as the part (1).

7. A method for preparing a ceramic matrix composite hanging point part according to any one of claims 1-6, characterized in that, Following roughing and preceding finishing, a calibration deposition step is also included: SiC substrate deposition was performed on the rough-machined part (1); It also includes step 5) decorative deposition: to improve the final surface uniformity of the part and to repair exposed fibers; Step 3) includes the following steps: 3.1) Interface layer deposition The preform with graphite tooling mold (3) is loaded into the furnace and the interface layer is deposited so that the interface layer thickness reaches 80-400nm. The preform is then removed from the furnace. The interface layer can be selected from pyrolytic carbon PyC, boron nitride BN and PyC+BN composite interface layer according to the different service conditions of the parts. 3.2) SiC substrate deposition The burrs on the preform are removed, and SiC matrix deposition is performed on the preform to achieve a density of 1.3~2.5 g / cm³. 3 , thus obtaining the blank of part (1).

8. The method for preparing a ceramic matrix composite hanging point part according to claim 7, characterized in that: In step 1.1), the fiber cloth is C fiber cloth, SiC fiber cloth, or Al2O3 fiber cloth; In step 3.1), the conditions for interface layer deposition are as follows: the vacuum degree in the furnace is evacuated to ≤20 Pa, heating is started, Ar, propylene and N2 are introduced, and when the temperature reaches the range of 400~1200 ℃, the temperature is held for 30~150 h, and then the temperature is lowered to below 50℃ and the parts are taken out. In step 3.2), the conditions for SiC substrate deposition are as follows: the vacuum degree is evacuated to ≤1000 Pa, and silane is extracted, the temperature is increased, Ar is introduced, the temperature is maintained, H2 is introduced, and the temperature is decreased in sequence.

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