Deep V-shaped ceramic matrix composite component forming device and forming method

Abstract

The invention provides a deep V-shaped ceramic matrix composite component forming device and method. The forming device comprises a bottom die, an outer die and an inner die. The outer die is connected to the bottom die; the inner mold is connected to the bottom mold, and the bottom mold, the outer mold and the inner mold are encircled to form a cavity for forming the deep V-shaped ceramic matrix composite component; wherein the inner die comprises a V-shaped main body die and a plurality of small-section dies connected to the V-shaped main body die, the plurality of small-section dies are arranged in the narrow opening position and are sequentially connected in the length direction, and the plurality of small-section dies are provided with die drawing angles in the length direction. The deep V-shaped ceramic matrix composite component can be formed and prepared, and demolding is convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material forming, and more specifically to a deep V-shaped ceramic-based composite material component forming device and a forming method. Background Art

[0002] Ceramic matrix composites are made of fiber reinforcement and ceramic matrix, combining the high temperature stability, excellent corrosion and wear resistance of ceramic materials and the high strength and fracture toughness of reinforcing fibers, and perform well under extreme conditions. Continuous fiber reinforced silicon carbide ceramic matrix composites are increasingly widely used in aero-engine hot end components, advanced aircraft thermal protection systems and other fields due to their good high temperature stability and high temperature mechanical properties.

[0003] In the manufacturing process of ceramic matrix composite components, molding technology is crucial to the structural stability and service life of the components. At present, the more mature molding method is molding, that is, the pre-impregnated fiber preform is placed in the mold cavity of the mold, and the press applies appropriate pressure and temperature to melt the resin and evenly penetrate the fiber before solidification. However, this method is mostly used for molding plate-type components, and it is difficult to achieve molding of other special-shaped parts.

[0004] V-shaped components usually refer to components with V-shaped cross-section or morphological characteristics. Composite V-shaped components are widely used in aircraft structures due to their excellent properties such as light weight, high strength, high temperature resistance, and wear resistance, such as the leading edge, wing beam, fuselage structure, and engine hot end components of the aircraft. It is of great significance to study the forming method of V-shaped ceramic matrix composite components. Variable cross-section deep V-shaped ceramic matrix composite components refer to a ceramic matrix composite component with a V-shaped cross-section that changes along the length direction and a deeper V-shaped opening. The variable cross-section design allows the component to have different shapes in different areas to adapt to the stress distribution and functional requirements of the structure. The deep V-shaped cross-section design can improve the bending strength and stiffness of the component, while reducing air resistance and improving fluid dynamics. However, due to the surface interference caused by the cross-section change and the friction resistance between the mold and the component after densification, there is a technical problem that the variable cross-section deep V-shaped ceramic matrix composite component is difficult to demold after densification. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is that the existing deep V-shaped ceramic-based composite material components are difficult to form and difficult to demould after forming.

[0007] (II) Technical solution

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] In the first aspect, the present invention provides a deep V-shaped ceramic-based composite material component forming device, which is used to form a deep V-shaped ceramic-based composite material component, wherein the deep V-shaped ceramic-based composite material component has a narrow mouth position, and includes a bottom mold, an outer mold and an inner mold; the outer mold is connected to the bottom mold; the inner mold is connected to the bottom mold, and the bottom mold, the outer mold and the inner mold together form a cavity for forming the deep V-shaped ceramic-based composite material component; wherein the inner mold includes a V-shaped main mold and a plurality of small-section molds connected to the V-shaped main mold, wherein the plurality of small-section molds are arranged inside the narrow mouth position and are connected in sequence along the length direction, and the plurality of small-section molds are provided with draft angles along the length direction.

[0010] Preferably, the section mold is provided with a fixing block, the V-shaped main body mold is provided with a snap-fit ​​groove, and the fixing block is snap-fitted to the snap-fit ​​groove.

[0011] Preferably, it further comprises a top cover and a plurality of fasteners, wherein the fasteners fasten the top cover to the outer mold, and the fasteners fasten the top cover to the inner mold.

[0012] Preferably, both the bottom mold and the outer mold are provided with impregnation holes.

[0013] Preferably, a part of the sub-section molds are sequentially connected along the length direction to form a first half mold, and another part of the sub-section molds are sequentially connected along the length direction to form a second half mold, and the first half mold and the second half mold are arranged opposite to each other and connected.

[0014] Preferably, a first connecting surface is provided between two adjacent sub-section molds of the first half mold, and a second connecting surface is provided between two adjacent sub-section molds of the second half mold, and the first connecting surface and the second connecting surface are arranged alternately.

[0015] In a second aspect, the present invention further provides a molding method, using the deep V-shaped ceramic matrix composite material component molding device described in any one of the above technical solutions to prepare a deep V-shaped ceramic matrix composite material component, the molding method comprising the following steps:

[0016] Weaving a composite material raw material to prepare a continuous fiber preform, and depositing an interface layer on the surface of the continuous fiber preform to obtain a composite material preform;

[0017] The plurality of the sub-section molds and the V-shaped main mold are bonded and connected by a room temperature adhesive to form an inner mold, the composite material preform is placed in the mold cavity, and the bottom mold, the outer mold and the inner mold are fastened and connected to form a combined tooling;

[0018] Placing the combined tooling in an impregnation liquid, and using a precursor impregnation and cracking method to densify the composite material preform to form a densified component;

[0019] After densification is completed, the densified component is separated from the bottom mold, the outer mold and the inner mold;

[0020] The densified component is processed to form a deep V-shaped ceramic matrix composite material component with a preset size.

[0021] Preferably, the composite material raw material includes carbon fiber and silicon carbide fiber.

[0022] Preferably, the material of the interface layer includes pyrolytic carbon, boron nitride and silicon carbide.

[0023] Preferably, the impregnation liquid.

[0024] (III) Beneficial effects

[0025] The above technical solution of the present invention has at least the following advantages:

[0026] 1. In the present invention, the inner mold is divided into a V-shaped main mold connected to each other and a plurality of small-section molds connected to the V-shaped main mold. The V-shaped main mold can be demolded along the V-shaped opening direction of the component, and the plurality of small-section molds can be demolded along the length direction of the V-shaped component. The demolding process is not restricted by the width of the narrow mouth. The present invention can effectively solve the problem of the difficulty of demolding deep V-shaped ceramic-based composite components with variable cross-section characteristics and narrow mouth positions. Compared with the method of mechanical processing combined with manual removal of the inner cavity graphite mold, the operation is simple, which greatly saves manpower and material costs, and there will be no excessive graphite residue.

[0027] 2. In the present invention, the bottom mold, outer mold and inner mold are all made of graphite material, which can form a ceramic-based composite material component with high surface accuracy and uniform fiber volume fraction by utilizing the advantages of graphite material such as high temperature resistance, stable molding and strong designability. In addition, the bottom mold, outer mold and inner mold made of graphite material can be reused, which greatly saves the manufacturing cost and time of mass production of components.

[0028] 3. In the present invention, the inner mold includes a V-shaped main mold and a plurality of sub-section molds connected to the V-shaped main mold. The plurality of sub-section molds, as well as the V-shaped main mold and the plurality of sub-section molds are connected by room temperature adhesive. During the high-temperature cracking process, the room temperature adhesive will decompose. Compared with the integral mold, the contact area between the sub-section mold and the component is smaller, which reduces the friction of demolding and facilitates demolding. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic structural diagram of a deep V-shaped ceramic matrix composite material component forming device provided in an embodiment of the present invention.

[0031] Figure 2 It is a schematic structural diagram of a deep V-shaped ceramic matrix composite material component provided by an embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the structure of the inner mold provided by an embodiment of the present invention.

[0033] Figure 4 It is a schematic structural diagram of a subsection mold provided by an embodiment of the present invention.

[0034] The reference numerals in the figures are:

[0035] 10. Deep V-shaped ceramic matrix composite component; 11. Narrow mouth position; 1. Bottom mold; 2. Outer mold; 3. Inner mold; 4. Top cover; 5. Impregnation hole; 31. V-shaped main body mold; 32. Section mold; 321. Fixing block; 41. Bolt hole; 42. Pin hole. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly located on the other element or indirectly located on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0038] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0040] like Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, an embodiment of the present invention provides a deep V-shaped ceramic-based composite component molding device for molding a deep V-shaped ceramic-based composite component 10, wherein the deep V-shaped ceramic-based composite component 10 has a narrow mouth position 11, and includes a bottom mold 1, an outer mold 2 and an inner mold 3; the outer mold 2 is connected to the bottom mold 1; the inner mold 3 is connected to the bottom mold 1, and the bottom mold 1, the outer mold 2 and the inner mold 3 are surrounded to form a cavity for molding the deep V-shaped ceramic-based composite component 10; wherein the inner mold 3 includes a V-shaped main body mold 31 and a plurality of small section molds 32 connected to the V-shaped main body mold 31, wherein the plurality of small section molds 32 are arranged inside the narrow mouth position 11 and are sequentially connected along the length direction, and the plurality of small section molds 32 are provided with draft angles along the length direction.

[0041] Specifically, the shape of the component to be formed in this embodiment is as follows: Figure 2 As shown, the component is a variable cross-section structure and has a narrow mouth position. At the narrow mouth position, the opening width of the narrow mouth is smaller than the width of the bottom mold, so it is difficult to demould along the V-shaped opening direction. In addition, when the component is very long, the cross-section changes, and there is a large friction resistance between the component and the mold after densification, the mold located inside the narrow mouth position is difficult to be pulled out along the left and right sides (length direction). In this embodiment, the inner mold 3 is split into a V-shaped main mold 31 connected to each other and a plurality of small section molds 32 connected to the V-shaped main mold 31. The V-shaped main mold 31 can be demoulded along the V-shaped opening direction of the component, and the plurality of small section molds 32 can be demoulded along the length direction of the V-shaped component, thereby solving the problems existing in the above-mentioned prior art.

[0042] In one embodiment, the subsection mold 32 is provided with a fixed block 321, and the V-shaped main body mold 31 is provided with a snap-in groove (not shown), and the fixed block 321 is snapped into the snap-in groove. Specifically, the purpose of setting the snap-in groove is to prevent the inner cavity mold position from moving during the molding process of the deep V-shaped ceramic-based composite material component 10, causing the profile to change. At the same time, since the deep V-shaped ceramic-based composite material component 10 and the mold are very easy to stick together during the densification process, the fixed block provides a force point for the file, which is convenient for pushing the fixed block to demold by the file. In addition, when the V-shaped main body mold 31 and the plurality of subsection molds 32 are split, it is necessary to consider that the splitting surface has a certain width, which is convenient for setting the fixed block, and the subsection mold will not be disconnected when moving left and right. More specifically, the setting position of the fixed block 321 is higher than the narrow mouth position, that is, when the fixed block 321 is in the component, it protrudes from the narrow mouth position of the component to facilitate contact with the file, thereby facilitating demolding.

[0043] In one embodiment, a top cover 4 and a plurality of fasteners (not shown) are further included, wherein the fasteners fasten the top cover 4 and the outer mold 2, and the fasteners fasten the top cover 4 and the inner mold 3. Specifically, a bolt hole 41 is provided at a corresponding position on the top cover 4 for inserting a fixing bolt, and a pin hole 42 is provided at a corresponding position on the top cover 4 for inserting a pin. The pin is used to realize the positioning and installation of the top cover 4 and other components, and the bolt is used to realize the fastening connection of the top cover 4 and other components.

[0044] In one embodiment, the fasteners include bolts and pins.

[0045] In one embodiment, both the bottom mold 1 and the outer mold 2 are provided with impregnation holes 5. The impregnation holes 5 on the outer mold 2 penetrate the outer mold 2 so that the impregnation liquid can pass through the outer mold 2 to impregnate the material in the cavity. Under the premise of ensuring the mechanical strength of the mold, the impregnation holes are designed along a certain direction to improve the impregnation efficiency.

[0046] In one embodiment, the bottom mold 1, the outer mold 2 and the inner mold 3 are made of graphite. The cracking temperature of the ceramic-based composite material is generally higher than 1000°C. In order to ensure the structural stability of the shaping mold, high-purity graphite with high temperature resistance, high strength and excellent machinability is generally selected to manufacture the bottom mold 1, the outer mold 2 and the inner mold 3.

[0047] In one embodiment, a portion of the mold sections are sequentially connected along the length direction to form a first half mold, and another portion of the mold sections are sequentially connected along the length direction to form a second half mold, and the first half mold and the second half mold are arranged opposite to each other and connected. Figure 4As shown, section mold A1, section mold B1, section mold C1, section mold D1 and section mold E1 are connected in sequence along the length direction to form a first half mold, and section mold A2, section mold B2, section mold C2, section mold D2 and section mold E2 are connected in sequence along the length direction to form a second half mold.

[0048] In the prior art, the two sides of the mold located in the narrow mouth position 11 are in contact with the component respectively. During the densification process of the component, both sides of the component are easily adhered to the mold. In this embodiment, the inner mold 3 includes a V-shaped main mold 31 and a plurality of segment molds 32 connected to the V-shaped main mold 31. The multiple segment molds 32 and the V-shaped main mold 31 and the multiple segment molds 32 are connected by room temperature adhesive. During the high temperature cracking process, the room temperature adhesive will decompose. Compared with the overall mold, the contact area between the segment mold 32 and the component is small, which reduces the friction of demoulding and is easy to demould.

[0049] In one embodiment, a first connection surface P1 is provided between two adjacent sub-section molds of the first half mold, and a second connection surface P2 is provided between two adjacent sub-section molds of the second half mold. The first connection surface P1 and the second connection surface P2 are alternately arranged.

[0050] In a second aspect, the present invention further provides a molding method, using any one of the deep V-shaped ceramic matrix composite material component molding devices in the above technical solutions to prepare a deep V-shaped ceramic matrix composite material component, the molding method comprising the following steps:

[0051] Weaving the composite material raw material to prepare a continuous fiber preform, and depositing an interface layer on the surface of the continuous fiber preform to obtain a composite material preform;

[0052] The inner mold 3 is formed by bonding a plurality of segment molds 32 and a V-shaped main mold 31 with a room temperature adhesive, placing the composite material preform in the mold cavity, and fastening the bottom mold 1, the outer mold 2 and the inner mold 3 to form a combined tooling;

[0053] Placing the combined tooling in an impregnation liquid, and using a precursor impregnation and cracking method to densify the composite material preform to form a densified component;

[0054] After densification is completed, the densified component is separated from the bottom mold 1, the outer mold 2 and the inner mold 3;

[0055] The densified component is processed to form a deep V-shaped ceramic matrix composite component with a preset size.

[0056] In one embodiment, the composite material raw material includes carbon fiber and silicon carbide fiber.

[0057] In one embodiment, the material of the interface layer includes pyrolytic carbon (PyC), boron nitride (BN) and silicon carbide (SiC).

[0058] In one embodiment, the impregnation liquid is a polycarbosilane organic solution or a polymethylsilane organic solution.

[0059] The following is a specific embodiment provided by the present invention:

[0060] The deep V-shaped ceramic matrix composite material component 10 has a component size of 324 mm×81 mm×72 mm and a thickness of 2.7 mm. Figure 2 The molding method comprises the following steps:

[0061] Step 1, prepare a continuous fiber preform: SiC fiber and the like are used as raw materials to prepare a continuous fiber preform by weaving. The outer surface of the continuous fiber preform is basically consistent with the outer surface of the component. The size of the continuous fiber preform is: 351mm×90mm×81mm, the thickness is 4.2mm, the margin of each edge is 15mm, the margin of the inner surface is 1.0mm, the margin of the outer surface is 0.5mm, and the structure of the continuous fiber preform is a 2.5D structure. The continuous fiber preform is placed in a chemical vapor deposition furnace to prepare a pyrolytic carbon interface layer. The specific preparation process of the pyrolytic carbon interface layer is as follows: methane is used as the carbon source, vacuum is drawn before deposition, the deposition temperature is 1150℃, the furnace pressure is maintained at about 3Kpa, the flow rate is 2000ml / min, the deposition time is 20h, and the interface layer weight gain is about 4-5%.

[0062] Step 2, design and manufacture a deep V-shaped ceramic matrix composite component forming device: Design a forming device according to the size and shape of the deep V-shaped ceramic matrix composite component 10. The structural dimensions of the cavity formed by the bottom mold 1, the outer mold 2 and the inner mold 3 for forming the deep V-shaped ceramic matrix composite component 10 are consistent with the dimensions of the continuous fiber preform structure, and the dimensions are 351mm×207mm×207mm. The inner mold 3 is split up and down at a position about 7mm above the narrow mouth position to form a V-shaped main mold and a lower half mold. The lower half mold is split from the middle downward along the length direction of the component to form two long strip molds, and then the two long strip molds are staggered and disconnected at a distance (about 70-80mm) to form a plurality of small section molds. A fixed block is designed at the top of each small section mold, and a gold clamping groove is set at the corresponding position of the V-shaped main mold. Impregnation holes are set on the front and bottom of the overall mold composed of the bottom mold, the outer mold and the inner mold, and bolt holes 41 and pin holes 42 are set at the same time for pressing and positioning. The materials of the bottom mold, outer mold and inner mold are high-purity graphite.

[0063] Step 3, pre-forming components: before molding, use AB glue to bond the V-shaped main mold 31 and multiple section molds 32 together, place the composite material preform in the mold cavity, and achieve pre-forming of the composite material preform through the self-locking bonding force of the mold.

[0064] Step 4, matrix densification: solid polycarbosilane (PCS) is dissolved in xylene to prepare a polycarbosilane organic solution with a mass concentration of 50wt%. The composite preform is densified by the conventional PIP process, and the densification and demoulding are completed after 10 times of impregnation-cracking. The demoulding method is: remove the top cover 4, the outer mold 2, the bottom mold 3 and the V-shaped main mold 31 in turn, use a file to press the fixed block 321 above the sub-section mold 32, and remove multiple sub-section molds in turn along the demoulding direction. Specifically, Figure 4 As shown, in the present embodiment, a plurality of sub-section molds include sub-section mold A1, sub-section mold A2, sub-section mold B1, sub-section mold B2, sub-section mold C1, sub-section mold C2, sub-section mold D1, sub-section mold D2, sub-section mold E1 and sub-section mold E2. The width of the end where the sub-section mold A1 and the sub-section mold A2 are located is wider, and the width of the end where the sub-section mold E1 and the sub-section mold E2 are located is narrower. When demolding, the sub-section molds are disassembled from the wider end to the narrower end in sequence.

[0065] Step 5, processing: the densified component is finely processed by mechanical processing to produce a deep V-shaped ceramic matrix composite component with a shape and size that meets the requirements.

[0066] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep V-shaped ceramic matrix composite material component forming device, characterized in that: Used for forming a deep V-shaped ceramic matrix composite component, wherein the deep V-shaped ceramic matrix composite component has a narrow mouth position, comprising: Bottom mold; An outer mold connected to the bottom mold; An inner mold connected to the bottom mold, wherein the bottom mold, the outer mold and the inner mold together form a cavity for molding a deep V-shaped ceramic-based composite material component; Among them, the inner mold includes a V-shaped main mold and a plurality of small section molds connected to the V-shaped main mold, the plurality of small section molds are arranged inside the narrow mouth position and are connected in sequence along the length direction, and the plurality of small section molds are provided with draft angles along the length direction.

2. The deep V-shaped ceramic matrix composite material component forming device according to claim 1, characterized in that: The section mold is provided with a fixing block, and the V-shaped main body mold is provided with a clamping groove, and the fixing block is clamped in the clamping groove.

3. The deep V-shaped ceramic matrix composite material component forming device according to claim 1, characterized in that: It also includes a top cover and a plurality of fasteners, wherein the fasteners fasten the top cover and the outer mold, and the fasteners fasten the top cover and the inner mold.

4. The deep V-shaped ceramic matrix composite material component forming device according to claim 1, characterized in that: The bottom mold and the outer mold are provided with impregnation holes.

5. The deep V-shaped ceramic matrix composite material component forming device according to claim 1, characterized in that: A portion of the segment molds are sequentially connected along the length direction to form a first half mold, and another portion of the segment molds are sequentially connected along the length direction to form a second half mold. The first half mold and the second half mold are arranged opposite to each other and connected.

6. The deep V-shaped ceramic matrix composite material component forming device according to claim 5, characterized in that: A first connecting surface is provided between two adjacent sub-section molds of the first half mold, and a second connecting surface is provided between two adjacent sub-section molds of the second half mold. The first connecting surface and the second connecting surface are arranged alternately.

7. A molding method, characterized in that: A deep V-shaped ceramic matrix composite component is prepared by using the deep V-shaped ceramic matrix composite component forming device according to any one of claims 1 to 6, wherein the forming method comprises the following steps: Weaving a composite material raw material to prepare a continuous fiber preform, and depositing an interface layer on the surface of the continuous fiber preform to obtain a composite material preform; The plurality of the sub-section molds and the V-shaped main mold are bonded and connected by a room temperature adhesive to form an inner mold, the composite material preform is placed in the mold cavity, and the bottom mold, the outer mold and the inner mold are fastened and connected to form a combined tooling; Placing the combined tooling in an impregnation liquid, and using a precursor impregnation and cracking method to densify the composite material preform to form a densified component; After densification is completed, the densified component is separated from the bottom mold, the outer mold and the inner mold; The densified component is processed to form a deep V-shaped ceramic-based composite material component with a preset size.

8. The molding method according to claim 7, characterized in that: The composite material raw materials include carbon fiber and silicon carbide fiber.

9. The molding method according to claim 7, characterized in that: The material of the interface layer includes pyrolytic carbon, boron nitride and silicon carbide.

10. The molding method according to claim 7, characterized in that: The impregnation liquid is a polycarbosilane organic solution or a polymethylsilane organic solution.

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