Forming die and method for thin-wall R-arc reinforced structure composite material component

Abstract

The invention relates to the technical field of ceramic matrix composite material forming, in particular to a forming die and method for a thin-wall R-arc reinforced structure composite material component, and the forming die comprises a bottom die, an outer die, an inner die and a top cover; the inner mold is located in an R-arc inner cavity of the thin-wall R-arc reinforced structure composite material component and connected to the bottom mold, the outer mold is connected to the bottom mold, the top cover is connected to the bottom mold and the outer mold, and a cavity used for forming the thin-wall R-arc reinforced structure composite material component is defined by the bottom mold, the outer mold, the inner mold and the top cover; a gasket used for enabling the R-arc outer molded surface of the component prefabricated body to be attached to the outer mold and the top cover is arranged at the position, making contact with the component prefabricated body, of the bottom mold, and a supporting cushion rope used for assisting in forming of the R-arc tip is arranged at the tip of the inner mold. The forming die and method of the thin-wall R-arc reinforced structure composite material component aim at solving the problem that the forming difficulty of the R-arc position of a thin-wall R-arc reinforced structure is large.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic-based composite material molding, and in particular to a molding die and a molding method for a thin-walled R-arc reinforced structure composite material component. Background Art

[0002] Continuous fiber reinforced ceramic matrix composites occupy an important position in the field of high-performance materials due to their excellent performance. This material has the excellent high-temperature stability, corrosion resistance and wear resistance of ceramic materials. At the same time, by introducing fiber reinforcement, it effectively overcomes the brittleness of ceramic materials and achieves the reinforcement and toughening of the ceramic matrix. Continuous fiber reinforced ceramic matrix composites have important application value in high-tech fields such as aerospace, new energy, and transportation due to their excellent performance. They are key materials to promote technological progress and industrial development.

[0003] In the manufacturing process of ceramic-based composites, molding technology is crucial. At present, the most commonly used composite material molding method is hot pressing molding, which is to heat and apply pressure to the pre-impregnated fiber-reinforced material and the matrix material in the mold cavity to solidify and shape them. However, hot pressing molding is mostly suitable for flat-type components, and is not suitable for the molding of complex structural components with bends or corners. For complex and special-shaped components, it is generally necessary to achieve near-net-size molding of the components through mold design. Regarding the mold design of the component, on the one hand, it is required to be able to achieve the shaping of the component to the greatest extent and to make the voids inside the material uniform through molding. On the other hand, it is required to reduce the processing allowance of the component and save production costs.

[0004] The thin-walled R-arc reinforced structure is a special structural form, which is usually used in situations where it is necessary to withstand large loads while requiring the structure to be lightweight. Thin wall means that the thickness of the component is very small relative to other dimensions (such as length, width, etc.), and R-arc means that some parts of the structure are arc-shaped. R represents the radius, which refers to the degree of curvature of the arc. The application of R-arc structure can effectively reduce stress concentration and improve the stability and bearing capacity of the structure when it is compressed or bent. The reinforced structure can significantly improve the strength and rigidity of the structure, and it also helps to disperse and transfer loads. However, the R-arc is difficult to form. On the one hand, the thickness becomes smaller due to the bending of the preform. On the other hand, the R-arc inner cavity mold is sharp and it is difficult to apply enough force to the preform to make its outer surface fit the mold. In addition, the ribs are very easy to bond with the mold during the molding-assisted precursor impregnation and cracking process, and there is a problem of difficulty in demolding after densification is completed.

[0005] Therefore, the inventor provides a molding die and method for a thin-walled R-arc reinforced structure composite material component. Summary of the invention

[0006] (1) Technical issues to be solved

[0007] The embodiments of the present invention provide a molding die and method for a thin-walled R-arc reinforced structure composite material component, which solves the technical problem that the R-arc of the thin-walled R-arc reinforced structure is difficult to mold.

[0008] (2) Technical solution

[0009] The present invention provides a molding die for a thin-walled R-arc reinforced structure composite material component, comprising a bottom mold, an outer mold, an inner mold and a top cover; the inner mold is located in the R-arc inner cavity of the thin-walled R-arc reinforced structure composite material component and is connected to the bottom mold, the outer mold is connected to the bottom mold, the top cover is connected to the bottom mold and the outer mold, and the bottom mold, the outer mold, the inner mold and the top cover together form a cavity for molding the thin-walled R-arc reinforced structure composite material component; a gasket for making the R-arc outer surface of the component preform fit the bottom mold is provided at the position where the bottom mold contacts the component preform.

[0010] Furthermore, the forming mold for the thin-walled R-arc reinforced structural composite material component is characterized in that a plurality of through holes are opened in the contact area between the bottom mold and the top of the rib of the component preform, the diameter of the through holes is smaller than a first preset value, and the distance between two adjacent through holes is smaller than a second preset value.

[0011] Furthermore, a support rope is provided at the contact position between the inner mold and the R-arc tip of the component preform, and the support rope fits the component preform along the entire length of the R-arc inner cavity, filling a gap of ≤0.2mm.

[0012] Furthermore, a slot for fixing the gasket is provided at a corresponding position of the bottom mold.

[0013] Furthermore, the molding die also includes a fixing block and a clamping groove, and the fixing block is arranged in the installation groove at the connecting positions on both sides of the bottom mold and the inner mold.

[0014] Furthermore, the molding die also includes a fastener, and the fastener is used to fasten and connect the bottom mold, the outer mold and the top cover.

[0015] Furthermore, the fasteners include bolts and pins, the bolts are used to achieve a fastened connection between the bottom mold, the outer mold and the top cover, and the pins are used to ensure that the relative positions of the bottom mold, the outer mold and the top cover do not change.

[0016] Furthermore, the molding die is made of a material with high temperature stability.

[0017] Furthermore, the bottom mold, the outer mold and the top cover are all provided with impregnation holes.

[0018] The present invention also provides a molding method using the molding die of the above-mentioned thin-walled R-arc reinforced structure composite material component, comprising the following steps:

[0019] A fiber preform is prepared by using a composite material raw material, and an interface layer is deposited on the surface of the fiber preform to form a thin-wall R-arc reinforced structure composite blank;

[0020] Loading the thin-walled R-arc reinforced structure composite material blank into the forming mold for pre-forming;

[0021] The pre-formed thin-walled R-arc reinforced composite blank is densified and demoulded using the PIP process.

[0022] The densified thin-walled R-arc reinforced structure composite material blank is processed to obtain a thin-walled R-arc reinforced structure composite material component, and a coating is prepared on the surface of the thin-walled R-arc reinforced structure composite material component.

[0023] Furthermore, the composite material raw materials include carbon fiber, silicon carbide fiber and silicon nitride fiber.

[0024] (3) Beneficial effects

[0025] In summary, the present invention arranges gaskets and support ropes to make the outer surface of the component preform at the R arc fit into the molding mold, which can realize the molding of the component while reserving less processing allowance, saving manufacturing costs and improving production efficiency. This is particularly important for the mass production of ceramic-based composite components with large-size R-arc structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are 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 creative work.

[0027] Figure 1 It is a schematic diagram of the overall structure of a molding die for a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention;

[0028] Figure 2 It is a schematic structural diagram of a groove at the bottom of a molding die for a thin-walled R-arc reinforced composite material component provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic structural diagram of a thin-walled R-arc reinforced structure composite material preform provided by an embodiment of the present invention;

[0030] Figure 4It is a schematic structural diagram of a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of a gasket installation structure of a molding die for a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention;

[0032] Figure 6 It is a structural schematic diagram of an inner mold and a supporting mat rope of a molding mold for a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention;

[0033] Figure 7 It is a structural schematic diagram of a bottom mold of a molding mold for a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention;

[0034] Figure 8 It is a schematic flow chart of a method for forming a thin-walled R-arc reinforced structure composite material component provided by an embodiment of the present invention.

[0035] In the figure:

[0036] 1-bottom mold; 101-slot; 102-groove; 2-outer mold; 3-inner mold; 4-top cover; 5-gasket; 6-through hole; 7-support pad rope; 8-fixing block; 9-installation slot; 10-impregnation hole; 11-bolt; 12-pin; 100-component prefabricated body; 200-thin-wall R-arc reinforced structure composite material component; 201-R-arc structure; 202-vertical rib structure. DETAILED DESCRIPTION

[0037] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments, and covers any modification, replacement and improvement of parts, components and connection modes without departing from the spirit of the present invention.

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present invention are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0040] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Figure 1 Schematic diagram of a molding die for a thin-walled R-arc reinforced composite material component provided by an embodiment of the present invention, see Figures 1 to 5 The mold may include a bottom mold 1, an outer mold 2, an inner mold 3 and a top cover 4; the inner mold 3 is located in the R-arc inner cavity of the thin-walled R-arc reinforced structure composite material component and is connected to the bottom mold 1, the outer mold 2 is connected to the bottom mold 1, and the top cover 4 is connected to the bottom mold 1 and the outer mold 2. The bottom mold 1, the outer mold 2, the inner mold 3 and the top cover 4 together form a cavity for molding a thin-walled R-arc reinforced structure composite material component; a gasket 5 for making the R-arc outer surface of the component preform 100 fit the outer mold 2 and the top cover 4 is provided at the position where the bottom mold 1 contacts the component preform 100.

[0042] In the above embodiment, the gasket 5 is located between the bottom mold 1 and the component preform 100 (eg Figure 5 As shown), fixed by the card slot 101 on the bottom mold (as shown Figure 7 As shown in the figure, the gasket 5 extrude the component preform 100 so that its R-arc outer surface fits the mold as much as possible, thereby solving the problem of insufficient margin of the outer surface at the R-arc. The gasket 5 needs to have a certain length, and its thickness needs to be as close to the thickness of the cavity as possible, in order to prevent the component preform 100 from wrinkling due to uneven force during the extrusion process, thereby preparing a thin-walled R-arc reinforced structure composite material component 200, specifically a thin-walled R-arc reinforced structure ceramic-based composite material component. The height of the gasket 5 can be calculated based on the size of the component preform 100 and the molding mold.

[0043] As an optional implementation, Figure 1 As shown, a support rope 7 is provided at the contact position between the inner mold 3 and the R-arc tip of the component preform 100, and the support rope 7 fits the component preform 100 along the entire length of the R-arc inner cavity.

[0044] Specifically, the support rope 7 is located at the tip of the inner mold 3 and fits in the inner bending of the R arc of the component preform 100. Figure 1 and 6As shown, it is fixed at the tip of the inner mold 3 by transparent tape, and the necessary support force is provided to the R-arc bend to assist in the forming of the R-arc tip. The length of the support pad rope 7 needs to be longer than the R-arc length of the component preform 100, and the diameter needs to be equal to or slightly larger than the diameter of the R-arc inner profile arc. The purpose is to enable the compressed support pad rope 7 to effectively fill the gap between the component preform 100 and the inner mold 3 at the R-arc position and generate the necessary support force for the component preform 100. After fixation, the support pad rope 7 fits tightly to the component preform 100 along the entire length of the R-arc inner cavity, and the filling gap is ≤0.2mm. The length of the support pad rope 7 is greater than the R-arc length of the component preform 100, and the diameter of the support pad rope 7 is 1.0 to 1.2 times the diameter of the R-arc arc of the component preform 100.

[0045] In addition, the support mat rope 7 needs to be resistant to high temperatures, and the preferred material is a rope woven from carbon fiber or silicon carbide fiber.

[0046] As an optional implementation, Figure 2 As shown, a plurality of through holes 6 are provided in the contact area between the bottom mold 1 and the rib top of the component preform 100. Specifically, by designing a plurality of through holes 6 at the top of the rib, after the densification is completed, the hole walls between the through holes are broken by applying local mechanical impact to form a coherent ejection channel, and the back ejection method is adopted to realize the efficient demoulding of the reinforced structure ceramic matrix composite component. On the one hand, it avoids the damage to the component that may be caused by direct demoulding. On the other hand, compared with the traditional method of removing the mold by mechanical processing, the back ejection method can realize the efficient demoulding of the reinforced structure ceramic matrix composite material, saving a lot of manpower and material costs. Among them, the single hole diameter range of the through hole 6 is 1.5 to 3 mm, that is, the first preset value is 3 mm, the spacing between two adjacent through holes 6 is 2 to 5 mm, that is, the second preset value is 5 mm, and the hole wall thickness is designed to be 0.5 to 2 mm, in order to balance the strength and fragility of the mold. The through holes 6 are arranged in a linear array along the length direction of the rib, and 3 to 8 through holes are set at the top of each rib. The specific number is determined according to the rib length and load distribution.

[0047] As an optional implementation, Figure 1 and 5 As shown, the molding die further includes a fixing block 8 and a mounting groove 9, and the fixing block 8 is disposed in the mounting groove 9 at the connection position on both sides of the bottom mold 1 and the inner mold 3. Specifically, the fixing block 8 is clamped in the mounting groove 9 to prevent the relative position of the inner mold 3 and the bottom mold 1 from shifting during the molding process, causing the molding surface to change.

[0048] like Figure 1As shown, the molding die also includes a fastener, which fastens the bottom mold 1, the outer mold 2, and the top cover 4. Specifically, the fastener includes a bolt 11 and a pin 12, the bolt 11 is used to achieve a fastening connection between the bottom mold 1, the outer mold 2, and the top cover 4, and the pin 12 is used to ensure that the relative positions of the bottom mold 1, the outer mold 2, and the top cover 4 do not change.

[0049] As an optional implementation, see Figure 2 , a groove 102 is provided at the bottom of the bottom mold 1. The large-sized groove 102 is designed at the bottom of the bottom mold 1 in order to reduce the weight of the mold, save costs and improve production efficiency.

[0050] As an optional implementation, the molding die is made of a material with high temperature stability, specifically high-purity graphite. Among them, since the cracking temperature of ceramic-based composite materials is generally higher than 1000°C, graphite has good high-temperature stability. By utilizing the excellent high-temperature stability and designability of graphite materials, ceramic-based composite components with high surface accuracy and uniform fiber volume fraction can be formed.

[0051] As an optional implementation, see Figure 1 The bottom mold 1, the outer mold 2 and the top cover 4 are all provided with impregnation holes 10. The function of the impregnation holes 10 is to allow the impregnation liquid to pass through the mold to impregnate the component. The design of the impregnation holes 10 requires that the mold strength is not affected as much as possible.

[0052] Figure 8 A method for forming a thin-walled R-arc reinforced composite material component is provided in an embodiment of the present invention. Figure 8 , the method may include the following steps:

[0053] S100, preparing a fiber preform using a composite material raw material, and depositing an interface layer on the surface of the fiber preform to form a thin-walled R-arc reinforced structure composite blank;

[0054] S200, placing a thin-walled R-arc reinforced structure composite material blank into a forming mold and fastening and connecting it with fasteners for pre-forming;

[0055] S300, densifying the pre-formed thin-walled R-arc reinforced composite material blank by using a PIP (Polymer Impregnation Pyrolysis) process and then demoulding;

[0056] S400, processing the densified thin-walled R-arc reinforced structure composite material blank to obtain a thin-walled R-arc reinforced structure composite material component, and preparing a coating on the surface of the thin-walled R-arc reinforced structure composite material component.

[0057] In the above embodiments, the composite material raw material includes carbon fiber, silicon carbide (SiC) fiber, silicon nitride (Si3N4) fiber, etc. The interface layer includes pyrolytic carbon (PyC), boron nitride (BN) and other composite interfaces, etc. The processing methods of the blank include mechanical processing, laser processing, ultrasonic assisted processing, etc. The coating includes SiC coating, EBC coating and other composite coatings.

[0058] Example 1

[0059] In this embodiment, the specific dimensions of the thin-walled R-arc reinforced ceramic matrix composite material component are 477 mm×126 mm×45 mm, the thickness is 2.8 mm, and the shape of the component is as follows: Figure 4 The molding method includes the following steps:

[0060] 1. Preparation of continuous fiber preform: Use the third generation SiC fiber to weave the preform, its shape is as follows Figure 3 As shown, its braided structure is a 2.5D structure with dimensions of 504mm×189mm×27mm, a thickness of 4.2mm, and an inner and outer surface margin of 0.75mm. The preform is placed in a chemical vapor deposition furnace to prepare a PyC interface layer. The specific process is: using propane as a carbon source, vacuuming before deposition, the deposition temperature is 1150°C, the furnace pressure is about 3Kpa, the flow rate is 2000ml / min, the deposition time is 20h, and the interface layer weight increases by 4-5%.

[0061] 2. Design and manufacture molds for thin-walled R-arc reinforced ceramic matrix composite components: mold structure such as Figure 3 As shown, the size is 506mm×222mm×113mm. The mold is made of high-purity graphite.

[0062] 3. Pre-forming of components: Before molding, use AB glue to bond the inner mold and the bottom mold together, and use transparent tape to fix the carbon fiber braided rope at the contact position between the inner mold and the R arc tip of the preform. The rope length is 515mm and the diameter is 2mm. Put the blank upside down on the mold, insert the ribs into the mold, cover the top cover and clamp it with a bow clamp. Next, bend the tail of the preform along the inner mold to form an R arc shape, and insert the gasket to squeeze it. Then, press the preform so that its inner surface is close to the mold, and push the outer mold along the length direction. After completing the mold, clamp it with a bow clamp, and finally install bolts and pins for pressing and positioning.

[0063] 4. Matrix densification: Prepare a solid polycarbosilane organic solution with a mass fraction of 50%, use the traditional impregnation cracking process to densify the matrix, and demould after 10 times. The specific demoulding method is to remove the top cover and outer mold after removing the pins and bolts, destroy the through hole wall above the bottom mold rib and clean the mold residue, use a metal ejector rod with a diameter of 8mm to eject the rib from the back, and finally remove the inner mold.

[0064] 5. Processing: Use mechanical processing to produce thin-walled R-arc reinforced structural ceramic-based composite components with shapes and sizes that meet the requirements.

[0065] 6. Surface deposition coating: SiC coating is prepared by CVD. The specific process is: the gas source is methyltrichlorosilane (MTS), the deposition temperature is 1200℃, the pressure is 8KPa, the deposition time is 24h, and the molar ratio of MTS to H2 flow is 1:8. The thickness of the prepared SiC coating is about 0.05mm.

[0066] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. In addition, for the sake of brevity, a detailed description of known methods and technologies is omitted here.

[0067] The above are only embodiments of the present application and are not limited to the present application. For those skilled in the art, the present application may have various changes and variations without departing from the scope of the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A forming die for a thin-walled R-arc reinforced structure composite material component, characterized in that: The invention comprises a bottom mold (1), an outer mold (2), an inner mold (3) and a top cover (4); the inner mold (3) is located in the R-arc inner cavity of the thin-walled R-arc reinforced structure composite material component and is connected to the bottom mold (1); the outer mold (2) is connected to the bottom mold (1); the top cover (4) is connected to the bottom mold (1) and the outer mold (2); the bottom mold (1), the outer mold (2), the inner mold (3) and the top cover (4) together form a cavity for molding the thin-walled R-arc reinforced structure composite material component; a gasket (5) for making the R-arc outer surface of the component preform (100) fit the outer mold (2) and the top cover (4) is provided at the position where the bottom mold (1) contacts the component preform (100).

2. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: A plurality of through holes (6) are provided in the contact area between the bottom mold (1) and the rib top of the component preform (100); the diameter of the through holes (6) is smaller than a first preset value, and the distance between two adjacent through holes (6) is smaller than a second preset value.

3. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: A support cushion rope (7) is provided at the contact position between the inner mold (3) and the R-arc tip of the component preform (100), and the support cushion rope (7) fits the component preform (100) along the entire length of the R-arc inner cavity, with a filling gap of ≤0.2 mm.

4. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: It also comprises a fixing block (8) and a mounting groove (9), wherein the fixing block (8) is arranged in the mounting groove (9) at the connection positions on both sides of the bottom mold (1) and the inner mold (3).

5. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: It also includes fasteners, which are used to fasten and connect the bottom mold (1), the outer mold (2) and the top cover (4).

6. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 5, characterized in that: The fastener comprises a bolt (11) and a pin (12); the bolt (11) is used to achieve a fastened connection between the bottom mold (1), the outer mold (2) and the top cover (4); and the pin (12) is used to ensure that the relative positions of the bottom mold (1), the outer mold (2) and the top cover (4) do not change.

7. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: The molding mold is made of a material with high temperature stability.

8. The forming die for the thin-walled R-arc reinforced structure composite material component according to claim 1, characterized in that: The bottom mold (1), the outer mold (2) and the top cover (4) are all provided with impregnation holes (10).

9. A molding method for a thin-walled R-arc reinforced composite material component using a molding die as claimed in any one of claims 1 to 8, characterized in that: The method comprises the following steps: A fiber preform is prepared by using a composite material raw material, and an interface layer is deposited on the surface of the fiber preform to form a thin-wall R-arc reinforced structure composite blank; The thin-walled R-arc reinforced structure composite material blank is loaded into the forming mold and fastened with fasteners for pre-forming; The pre-formed thin-walled R-arc reinforced composite blank is densified and demoulded using the PIP process. The densified thin-walled R-arc reinforced structure composite material blank is processed to obtain a thin-walled R-arc reinforced structure composite material component, and a coating is prepared on the surface of the thin-walled R-arc reinforced structure composite material component.

10. The molding method according to claim 9, characterized in that: Composite materials include carbon fiber, silicon carbide fiber and silicon nitride fiber.

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