Ceramic matrix composite integrally-formed blade and preparation method thereof

Abstract

The invention discloses a ceramic matrix composite integrally-formed blade and a preparation method thereof, and relates to the technical field of aero-engine preparation. The method comprises the following steps that fiber cloth is laid on the outer surface of a blade body mold, meanwhile, the fiber cloth is reserved at the two ends, and then the fiber cloth penetrates through the reserved fiber cloth and is laid; spreading the reserved fiber cloth on the outermost layer in a divergent manner, and circularly stacking; the fiber cloth forms an L-shaped laying layer along the mold, and the remaining reserved fiber cloth is flatly laid along the L-shaped laying layer; then, fiber cloth penetrates through the reserved fiber cloth and then is laid, and a U-shaped laying layer is formed; the stacking is cyclically carried out; suturing and fixing to obtain a blade preform; and carrying out subsequent treatment to obtain the ceramic matrix composite integrally formed blade. The integrally-formed laying layer structure is adopted, the complete fibers penetrate through the blade body, the blade crown and the edge plate and are sewn into a whole, so that the blade component can be integrally formed, the connection reliability problem between split parts is solved, and the overall reliability of the blade is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengine preparation, and in particular to a ceramic-based composite integrally formed blade and a preparation method thereof. Background Art

[0002] The blade components of the new generation of aircraft engines need to withstand increasingly harsh environmental loads. The performance of traditional high-temperature alloy materials has reached its limit and does not have the potential to meet the needs of future aircraft engine blades. It is urgent to develop new revolutionary materials to replace them. Ceramic matrix composites (CMC) combine the high strength, high hardness, high temperature resistance, corrosion resistance and other excellent properties of ceramics with the excellent toughness and fatigue resistance of fibers. The components made of CMC have the characteristics of low density, high temperature resistance, impact resistance, and long life. It is currently the fastest-growing and most widely used new material in the aviation field.

[0003] However, the application of CMC materials in aircraft engine blades still has the following problems to be optimized: 1. Structural design. Unlike high-temperature alloy materials, CMC materials have significant anisotropic properties, which are reflected in the fiber weaving method and direction. Therefore, designers are required to design the most reasonable component structure and fiber weaving direction based on the actual load conditions of the blades. However, due to the limitations of CMC manufacturing process, blade components with complex surface features can only be split into separate structures of blade body and edge plate, and connected into one through CMC connection technology; 2. Manufacturing process. Although CMC materials have excellent performance, in actual applications, solving high-precision molding and processing technology, especially combined with the small-size complex surface features of blades, puts forward higher requirements on the preform molding process. The common 2D fiber laying method is difficult to meet the complex surface molding. Therefore, only 3D or 2.5D fiber weaving technology with stronger interlayer bonding but weaker tensile, compression and bending strength can be used. The cost and performance need to be improved; 3. Reliability issues. In actual applications, CMC blades will be subjected to harsh environmental influences such as high temperature, high pressure, oxidative corrosion, thermal shock, etc., and the moving blades will also be subjected to huge centrifugal forces. Therefore, higher reliability is required. The connection of CMC blades is the weakest part of the blade component due to the lack of or even no continuous fibers. It is also the key to improving the reliability of the blade. Therefore, it is particularly important to optimize the structural design and process of the connection. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a ceramic matrix composite integrally formed blade and a preparation method thereof, so as to solve the reliability problem of CMC blades in the prior art due to less or even no continuous fibers at the connection.

[0005] The technical solution of the present invention to solve the above technical problem is as follows: Provide a ceramic-based composite integrally formed blade and a preparation method thereof, comprising the following steps:

[0006] S1: Taking the inner profile of the blade as a reference, a blade inner profile mold is manufactured; taking the outer profile of the blade as a reference, a blade outer profile left mold and a blade outer profile right mold are manufactured; taking the rib profile as a reference, a first rib mold and a second rib mold are manufactured; wherein the blade inner profile mold, the blade outer profile left mold, the blade outer profile right mold, the first rib mold and the second rib mold all have a plurality of suture holes perpendicular to the profile;

[0007] S2: laying fiber cloth on the outer surface of the blade inner profile mold, sewing and fixing, filling the cavity formed between the fiber cloths with fiber cloth, and reserving fiber cloth at both ends of the blade inner profile mold to obtain a blade preform;

[0008] S3: clamping the blade preform obtained in step S2 with a left mold for the blade outer profile and a right mold for the blade outer profile, and sew and fix them; then passing the cut fiber cloth through the reserved fiber cloth in step S2, and laying them along the edge plate surface; then cutting the outermost layer of the reserved fiber cloth in step S2, and laying them flat in a divergent shape along the edge plate surface; and cyclically stacking them to form an edge plate surface preform;

[0009] S4: using the same cyclic lamination method as in step S3, performing leaf crown laying to form a leaf crown preform, and suturing and fixing the preform using a leaf crown outer mold;

[0010] S5: Laying the fiber cloth into an L-shaped layer along the first rib mold, and sewing and fixing it on the edge panel preform in step S3;

[0011] S6: cutting the reserved fiber cloth remaining in the outermost layer of step S3, and laying it in a divergent shape along the side elevation of the L-shaped ply; then passing the cut fiber cloth through the reserved fiber cloth, and laying it along the edge plate surface and the side elevation of the L-shaped ply to form a U-shaped ply; and stacking in this way in a cycle to form a prefabricated body of vertical reinforcement;

[0012] S7: using a second rib mold to fix the U-shaped ply obtained in step S6, and sew and fix it to obtain a blade preform;

[0013] S8: subjecting the blade preform obtained in step S7 to chemical vapor infiltration, removing the mold to obtain a blade blank, and processing it to a designed size to obtain a ceramic-based composite integrally formed blade.

[0014] On the basis of the above technical solution, the present invention can also be improved as follows:

[0015] Furthermore, in step S2, the fiber cloth is firstly wound on the outer surface of the blade inner surface mold, and then the fiber cloth is clamped on the outer surface of the blade inner surface mold to complete the layer laying process.

[0016] The beneficial effect of adopting the above further technical solution is: making the inner surface of the blade body a complete fiber surface, and the outer surface of the blade body a complete fiber surface, ensuring that the inner and outer surfaces of the blade body of the final product meet the requirements of being smooth and without pits.

[0017] Furthermore, the cavity formed between the wound fiber cloth and the clamped fiber cloth is filled with fiber cloth and fixed with a curing agent.

[0018] Furthermore, the curing agent is a resin curing agent.

[0019] Furthermore, the resin curing agent is polyvinyl alcohol.

[0020] Further, in step S2, the lengths of the fiber cloths reserved at both ends are respectively greater than the length of the edge plate and the length of the blade crown.

[0021] Furthermore, in step S2, the thickness of the ply is increased by 0.5 mm compared to the designed thickness.

[0022] Furthermore, in step S3, part of the circumferential fibers of the outermost reserved fiber cloth are removed to complete the cutting process.

[0023] Further, in step S3, first, two layers of cut fiber cloth are passed through the reserved fiber cloth in step S2 and laid along the edge board surface; then the outermost two layers of reserved fiber cloth are cut and laid divergently along the edge board surface; then one layer of cut fiber cloth is passed through the reserved fiber cloth and laid along the edge board surface; the process of the outermost two layers of reserved fiber cloth and one layer of cut fiber cloth is repeated; finally, the outermost layer of reserved fiber cloth is cut and laid divergently along the edge board surface to complete the cyclic stacking process.

[0024] Further, repeat 2 times.

[0025] The beneficial effects of adopting the above-mentioned further technical solution are: 1. Ensure that the edge plate is within the designed thickness range; 2. The guide vane blade area and the edge plate area have complete continuous fibers, thereby increasing the strength of the connection area between the blade body and the edge plate; 3. The external surface of the final product is a complete fiber layer, which meets the requirements of a smooth and pit-free product surface.

[0026] Furthermore, in step S3, the thickness of the edge plate preform is increased by 0.5 mm compared with the designed thickness.

[0027] Furthermore, in step S4, the thickness of the blade crown preform is increased by 0.5 mm compared with the designed thickness.

[0028] Further, in step S6, part of the circumferential fibers of the outermost layer of the reserved fiber cloth remaining in step S3 are removed to complete the cutting process.

[0029] Furthermore, in step S6, the outermost layer of the reserved fiber cloth remaining in step S3 is first cut and laid out in a divergent manner along the side elevation of the L-shaped ply; then, one layer of the cut fiber cloth is passed through the reserved fiber cloth and laid out along the edge plate surface and the side elevation of the L-shaped ply to form a U-shaped ply; the aforementioned process is repeated; finally, four layers of the cut fiber cloth are passed through the reserved fiber cloth to complete the cyclic stacking process.

[0030] Further, repeat 2 times.

[0031] The beneficial effects of adopting the above-mentioned further technical solution are: 1. Ensure that the vertical ribs are within the designed thickness range; 2. There are complete continuous fibers inside the vertical ribs from the guide vane body area to the edge plate, thereby increasing the strength of the vertical ribs and the blade body; 3. The external surface of the final product is a complete fiber layer, meeting the requirements of a smooth and pit-free product surface.

[0032] Furthermore, in step S6, the thickness of the prefabricated rib body is increased by 0.5 mm compared with the designed thickness.

[0033] Furthermore, in steps S2-S6, the fiber cloth is a 2D fiber cloth.

[0034] Furthermore, in steps S2-S6, the raw material of the fiber cloth is silicon carbide fiber.

[0035] Furthermore, in steps S2-S7, suture fixation is performed using suture threads with the suture holes as paths.

[0036] Furthermore, the raw material of the suture thread is silicon carbide fiber.

[0037] Furthermore, in step S7, the thickness of the blade preform is increased by 0.5 mm compared with the designed thickness, and the length along the extension direction of the fiber cloth is increased by ≥5 mm compared with the designed length.

[0038] Furthermore, in step S8, after the mold is removed, acetone is used to remove the resin curing agent.

[0039] The present invention also provides a ceramic-based composite material integrally formed blade made by the method.

[0040] The present invention also provides application of the ceramic-based composite material integrally formed blade in the preparation of aero-engine blades.

[0041] The present invention has the following beneficial effects:

[0042] 1. The blade component body of the present invention is made of two-dimensional SiC fiber cloth stacked by a special method. There are complete continuous fibers between the blade body, the blade crown and the edge plate, which can significantly improve the reliability of the connection of traditional split blade components. Under the high temperature and dynamic and static load environment of the aircraft engine, it has high strength, rigidity and structural stability. The method of the present invention is suitable for the preparation of the same type of ceramic-based composite blades, and has guiding significance for the structural design of ceramic-based composite blades of aircraft engines and the preform preparation plan.

[0043] 2. The present invention designs a fiber preform of the 2D laying method according to the blade structure, so that the weakest connection of the blade component has complete fibers, and other parts have complete fiber bundles as much as possible. Then, the interface layer and the ceramic matrix can be prepared by CVI and other processes, so that the CMC blade has higher reliability under high-precision molding and processing technology.

[0044] 3. The present invention adopts an integrally formed layer structure, with complete fibers running through the blade body, blade crown, and edge plate, and sewing them into one body, so that the blade components can be integrally formed, solving the connection reliability problem between the separate parts and improving the overall reliability of the blade. In addition, the structure adopts 2D fiber cloth layer, which has higher tensile, compression, and bending strength than 2.5D and 3D woven CMC preforms, and is conducive to low-cost preparation. The present invention has guiding significance for the reliability design and preparation of the same type of ceramic-based composite blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic diagram of the blade component structure;

[0046] Figure 2 This is a schematic diagram of the fiber cloth laying of the blade preform;

[0047] Figure 3 It is a schematic diagram of the blade preform structure;

[0048] Figure 4 It is a schematic diagram of the blade structure;

[0049] Figure 5 It is a schematic diagram of the ply structure of the blade preform;

[0050] Figure 6 This is a schematic diagram of the inner surface forming of the blade prefabricated body;

[0051] Figure 7 This is a schematic diagram of the outer surface molding of the blade prefabricated body;

[0052] Figure 8 Illustration of the edge panel surface Figure 1 ;

[0053] Fig. 9 Illustration of the edge panel surface Figure 2;

[0054] Fig.10 This is a schematic diagram of the L-shaped ply of the vertical reinforcement;

[0055] Fig.11 This is a schematic diagram of reinforcement laying;

[0056] Fig.12 Schematic diagram of U-shaped ply laying of vertical reinforcement.

[0057] Among them, 1. blade crown; 2. blade body; 3. edge plate surface; 4. ribs; 5. blade body inner profile mold; 6. blade body outer profile left mold; 7. blade body outer profile right mold; 8. first rib mold; 9. second rib mold; 10. cavity; 11. reserved fiber cloth. DETAILED DESCRIPTION

[0058] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0059] Typical structure of blades Figure 1 As shown, it includes a blade crown 1, a blade body 2 and an edge plate, and the edge plate includes an edge plate surface 3 and vertical ribs 4.

[0060] The preform fiber cloth of the present invention is laid in the following direction: Figure 2 As shown. The blade preform is obtained as Figure 3 As shown. In order to ensure the later processing allowance, the thickness of the blade preform is increased by 0.5mm compared with the designed thickness, and the length along the elongation direction of the fiber cloth is increased by ≥5mm compared with the designed length. The fiber cloth of the blade body 2 and the fiber cloth of the edge plate of the present invention are connected in a stacked form, and the fiber cloth of the vertical rib 4 and the fiber cloth of the edge plate are integrated by a sewing process, so there are continuous fibers between each part, which can significantly improve the reliability of the blade.

[0061] Embodiment 1:

[0062] A method for preparing a ceramic-based composite integrally formed blade comprises the following steps:

[0063] S1: With the inner cavity profile of the blade body 2 of the blade as a reference, a blade body inner profile mold 5 (whose height is higher than the inner cavity profile of the blade body 2) is manufactured; with the outer profile of the blade body 2 of the blade as a reference, a blade body outer profile left mold 6 and a blade body outer profile right mold 7 are manufactured; with the profile of the rib 4 as a reference, a first rib mold 8 and a second rib mold 9 are manufactured; wherein the blade body inner profile mold 5, the blade body outer profile left mold 6, the blade body outer profile right mold 7, the first rib mold 8 and the second rib mold 9 all have a plurality of suture holes perpendicular to the profile;

[0064] Blade 2 structure Figure 4 As shown, the middle part is a cavity, and the rear part is a structure of unequal wall thickness;

[0065] S2: First, three layers of 2D fiber cloth are wound on the outer surface of the blade inner profile mold 5, and then seven layers of 2D fiber cloth are clamped on the outer surface of the blade inner profile mold 5 to complete the layering process, and sew and fix them. The fiber cloth is filled in the cavity 10 formed between the wound 2D fiber cloth and the clamped 2D fiber cloth, and fixed with a polyvinyl alcohol resin curing agent to solidify into a filling block. At the same time, 2D fiber cloth is reserved at both ends of the blade inner profile mold 5, and the length of the reserved 2D fiber cloth at both ends is respectively greater than the length of the edge plate and the length of the blade crown 1, so as to obtain a blade 2 preform; (see Figure 5-6 (shown)

[0066] S3: The blade body 2 preform obtained in step S1 is clamped by using the blade body outer profile left mold 6 and the blade body outer profile right mold 7, and sutured and fixed. Figure 7 As shown; first, two layers of cut 2D fiber cloth are passed through the reserved 2D fiber cloth in step S2, and laid along the edge board surface 3; then the outermost two layers of reserved 2D fiber cloth are cut (part of the circumferential fibers are removed), and laid along the edge board surface 3 in a divergent manner; then one layer of cut 2D fiber cloth is passed through the reserved 2D fiber cloth, and laid along the edge board surface 3; the process of the outermost two layers of reserved 2D fiber cloth and one layer of cut 2D fiber cloth is repeated twice; finally, the outermost layer of reserved 2D fiber cloth is cut again, and laid along the edge board surface 3 in a divergent manner, completing the cyclic stacking process to form the edge board surface 3 preform (thickness is 3.6 mm); (see Figure 8-9 (shown)

[0067] S4: using the same cyclic lamination method as in step S3, layering the blade crown 1 to form a blade crown 1 preform, and suturing and fixing it with a blade crown outer mold;

[0068] S5: 10 layers of 2D fiber cloth are formed into an L-shaped layer (thickness of 3 mm) along the first rib mold 8, and are sewed and fixed on the edge panel 3 preform in step S3; (see Fig.10 (shown)

[0069] S6: First, the reserved 2D fiber cloth remaining in the outermost layer of step S3 is cut (part of the circumferential fibers are removed), and laid out in a divergent manner along the side elevation of the L-shaped ply; then, one layer of the cut 2D fiber cloth is passed through the reserved 2D fiber cloth, and laid out along the edge panel surface 3 and the side elevation of the L-shaped ply to form a U-shaped ply; the above process is repeated twice; finally, four layers of the cut 2D fiber cloth are passed through the reserved 2D fiber cloth to complete the cyclic stacking process, and a preform of the vertical rib 4 (thickness is 6 mm) is formed; (see Figure 11-12 (shown)

[0070] S7: Use the second rib mold 9 to fix the U-shaped ply obtained in step S6, sew and fix it, and obtain a blade preform; (see Fig.12 (shown)

[0071] S8: The blade preform obtained in step S7 is subjected to chemical vapor infiltration. After removing the mold, an acetone solution is used to remove the resin curing agent, and the silicon carbide fiber is retained to obtain a blade blank, which is processed to a designed size to obtain a ceramic-based composite integrally formed blade.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a ceramic-based composite integrally formed blade, characterized in that: The following steps are involved: S1: Taking the inner cavity profile of the blade body (2) as a reference, a blade body inner profile mold (5) is manufactured; taking the outer profile of the blade body (2) as a reference, a blade body outer profile left mold (6) and a blade body outer profile right mold (7) are manufactured; taking the profile of the rib (4) as a reference, a first rib mold (8) and a second rib mold (9) are manufactured; wherein the blade body inner profile mold (5), the blade body outer profile left mold (6), the blade body outer profile right mold (7), the first rib mold (8) and the second rib mold (9) all have a plurality of suture holes perpendicular to the profile; S2: laying fiber cloth on the outer surface of the blade inner profile mold (5), sewing and fixing, filling the cavity (10) formed between the fiber cloths with fiber cloth, and reserving fiber cloth (11) at both ends of the blade inner profile mold (5), thereby obtaining a blade (2) preform; S3: using a left blade outer profile mold (6) and a right blade outer profile mold (7) to clamp the blade (2) preform obtained in step S2, and sew and fix it; then passing the cut fiber cloth through the reserved fiber cloth (11) in step S2, and laying it along the edge plate surface (3); then cutting the outermost layer of the reserved fiber cloth (11) in step S2, and laying it in a divergent shape along the edge plate surface (3); and cyclically stacking in this way to form an edge plate surface (3) preform; S4: using the same cyclic lamination method as in step S3, the blade crown (1) is laid to form a blade crown (1) preform, and the blade crown outer mold is used to sew and fix it; S5: Laying the fiber cloth into an L-shaped layer along the first rib mould (8), and sewing and fixing it on the edge panel (3) preform in step S3; S6: cutting the reserved fiber cloth (11) remaining in the outermost layer of step S3, and laying it out in a divergent shape along the side elevation of the L-shaped ply; then passing the cut fiber cloth through the reserved fiber cloth (11), and laying it out along the edge plate surface (3) and the side elevation of the L-shaped ply to form a U-shaped ply; and cyclically stacking in this way to form a preform of the vertical rib (4); S7: using a second rib mould (9) to fix the U-shaped ply obtained in step S6, and sew and fix it to obtain a blade preform; S8: subjecting the blade preform obtained in step S7 to chemical vapor infiltration, removing the mold to obtain a blade blank, and processing it to a designed size to obtain a ceramic-based composite integrally formed blade.

2. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In step S2, the fiber cloth is firstly wound around the outer surface of the blade inner profile mold (5), and then the fiber cloth is clamped on the outer surface of the blade inner profile mold (5), thereby completing the layering process.

3. The method for preparing a ceramic matrix composite integrally formed blade according to claim 2, characterized in that: The cavity (10) formed between the wound fiber cloth and the clamped fiber cloth is filled with fiber cloth and fixed with a curing agent.

4. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In step S3, firstly, two layers of cut fiber cloth are passed through the reserved fiber cloth (11) of step S2 and laid along the edge board surface (3); then, the outermost two layers of the reserved fiber cloth (11) are cut and laid in a divergent manner along the edge board surface (3); then, one layer of cut fiber cloth is passed through the reserved fiber cloth (11) and laid along the edge board surface (3); the process of the outermost two layers of the reserved fiber cloth (11) and one layer of cut fiber cloth is repeated; finally, the outermost layer of the reserved fiber cloth (11) is cut and laid in a divergent manner along the edge board surface (3), thereby completing the cyclic stacking process.

5. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In step S6, the outermost layer of the reserved fiber cloth (11) remaining in step S3 is first cut and laid out in a divergent manner along the side elevation of the L-shaped ply; then, one layer of the cut fiber cloth is passed through the reserved fiber cloth (11) and laid out along the edge plate surface (3) and the side elevation of the L-shaped ply to form a U-shaped ply; the aforementioned process is repeated; and finally, four layers of the cut fiber cloth are passed through the reserved fiber cloth (11) to complete the cyclic stacking process.

6. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In steps S2-S6, the fiber cloth is a 2D fiber cloth.

7. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In steps S2-S6, the raw material of the fiber cloth is silicon carbide fiber.

8. The method for preparing a ceramic matrix composite integrally formed blade according to claim 1, characterized in that: In step S7, the thickness of the blade preform increases by 0.5 mm compared with the designed thickness, and the length along the extension direction of the fiber cloth increases by ≥5 mm compared with the designed length.

9. A ceramic-based composite material integrally formed blade obtained by the method for preparing a ceramic-based composite material integrally formed blade according to any one of claims 1 to 8.

10. Use of the ceramic matrix composite integrally formed blade according to claim 9 in the preparation of aero-engine blades.

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