A forming method and mold for a C / SiC composite non-equal-wall-thickness special-shaped shaft sleeve

Abstract

The present application relates to a kind of C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming method, including tubular preform preparation, pull out cylindrical inner mold, insert polygonal prism inner mold, interface layer carbon deposition, heat treatment, silicon carbide matrix deposition, machining, the process of final silicon carbide matrix deposition.The present application also relates to a kind of C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming die, including cylindrical inner mold, polygonal prism inner mold, outer mold, reinforcing frame, inner mold wedge piece.Polygonal prism inner mold, inner mold wedge piece are provided with draw angle, and polygonal prism inner mold is used to open polygonal prism inner mold.The forming method of the present application, after two-dimensional plain weave carbon cloth is wound and fixed, C / SiC composite material non-equal wall thickness special-shaped shaft sleeve is obtained by chemical vapor infiltration CVI, and the fiber continuity of non-equal wall thickness special-shaped shaft sleeve is guaranteed, and interlaminar shear performance is effectively improved.The forming die of the present application guarantees the non-equal wall thickness of non-equal wall thickness special-shaped shaft sleeve and its preform.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon fiber reinforced ceramic matrix composite material preparation, and particularly relates to a C / SiC composite material non-equal-wall-thickness special-shaped shaft sleeve forming method and a mold. BACKGROUND

[0002] Carbon fiber reinforced ceramic matrix composite material becomes an ideal high-temperature structural material in the field of aerospace due to excellent performances such as high-temperature resistance, corrosion resistance, oxidation resistance, high strength and high toughness. Two-dimensional laminated fiber preform is widely used in the preparation of ceramic matrix composite material because of simple weaving process and low cost.

[0003] In order to obtain carbon fiber reinforced ceramic matrix composite material with good interlaminar bonding strength, when the fiber preform is shaped, the carbon fiber cloth is overlapped layer by layer to a certain thickness, then the carbon fiber cloth is formed into a required shape by means of a mold, and is pierced according to a specific needle method to obtain a carbon fiber preform with a certain bonding strength and different structures, and then SiC is deposited to obtain carbon fiber reinforced ceramic matrix composite material with good interlaminar bonding strength. Since the thickness of each layer of carbon fiber cloth in the carbon fiber reinforced ceramic matrix composite material is basically consistent, after layering, if the mold is used for forming, in order to ensure fiber continuity, only an equal-wall-thickness preform can be obtained. However, if the inner and outer surface structures of the component are different (non-equal-wall-thickness), and fiber continuity of the inner and outer surfaces of the two-dimensional laminated (2D) component after processing is required, the existing forming method cannot meet the requirements. SUMMARY

[0004] In order to overcome the deficiency that the mold cannot be used for forming in the preparation of the non-equal-wall-thickness special-shaped shaft sleeve, the application provides a C / SiC composite material non-equal-wall-thickness special-shaped shaft sleeve forming method and a mold.

[0005] The application solves the technical problems by adopting the technical solutions as follows:

[0006] A C / SiC composite material non-equal-wall-thickness special-shaped shaft sleeve forming method comprises the following steps:

[0007] Step 1, tubular preform preparation: a winding method is adopted, a carbon fiber cloth is wound on the circumferential surface of a cylindrical inner mold, and the outer diameter of the carbon fiber cloth is the same as the outer diameter of the special-shaped shaft sleeve preform, so that a tubular preform wound on the cylindrical inner mold is obtained.

[0008] Step 2, mold drawing: first, the outer mold is closed, two outer molds are arranged on the outer side of the tubular preform, the outer mold is matched with the length of the tubular preform along the axis direction, the outer mold is fixed by using a reinforcing frame, and the end face of the non-drawing angle end of the cylindrical inner mold is flush with the end face of the outer mold. Then, the cylindrical inner mold is drawn out from the tubular preform, and the drawing is started from the non-drawing angle end.

[0009] Step 3, mold insertion: firstly, the multi-prism inner mold is inserted into the carbon fiber preform, and the multi-prism inner mold is inserted in the reverse direction of the cylindrical inner mold extraction, from the non-draft angle end of the multi-prism inner mold to the end face of the non-draft angle end of the multi-prism inner mold. The end face of the non-draft angle end of the multi-prism inner mold is flush with the end face of the tubular preform. Secondly, the inner mold wedge is inserted: the inner mold wedge is inserted into the multi-prism inner mold from the non-draft angle end of the multi-prism inner mold, and the gap between the bottom of the inserted end of the inner mold wedge with a cylinder and the end face of the multi-prism inner mold is less than 0.05mm, to obtain a non-equal wall thickness special-shaped bushing preform.

[0010] Step 4, interface layer preparation and silicon carbide matrix deposition: the non-equal wall thickness special-shaped bushing preform is subjected to chemical vapor infiltration CVI, and after carbon deposition of the interface layer, heat treatment and silicon carbide matrix deposition, a non-equal wall thickness special-shaped bushing intermediate body with a set density is obtained.

[0011] Step 5, mechanical processing: the non-equal wall thickness special-shaped bushing intermediate body obtained in step 4 is subjected to mechanical processing according to the size requirements, to obtain a non-equal wall thickness special-shaped bushing intermediate body with a size meeting the requirements.

[0012] Step 6, final silicon carbide matrix deposition: the mechanically processed non-equal wall thickness special-shaped bushing intermediate body is subjected to final silicon carbide matrix deposition, to obtain a non-equal wall thickness special-shaped bushing with a density reaching the product set value.

[0013] The above C / SiC composite non-equal wall thickness special-shaped bushing forming method, the step 4, interface layer preparation and silicon carbide matrix deposition, further comprises:

[0014] The carbon deposition of the interface layer includes primary carbon deposition of the interface layer and secondary carbon deposition of the interface layer.

[0015] Primary carbon deposition of the interface layer: together with the mold, the non-equal wall thickness special-shaped bushing preform is placed into a chemical vapor infiltration device for carbon deposition of the interface layer, until the interface layer reaches the set thickness of the primary carbon deposition of the interface layer, and then taken out from the chemical vapor infiltration device, and the outer mold and the reinforcing frame are removed, to obtain a non-equal wall thickness special-shaped bushing intermediate body.

[0016] Secondary carbon deposition of the interface layer: together with the multi-prism inner mold, the non-equal wall thickness special-shaped bushing intermediate body subjected to the primary carbon deposition of the interface layer is placed into a chemical vapor infiltration device for secondary carbon deposition of the interface layer, until the interface layer reaches the set thickness of the secondary carbon deposition of the interface layer.

[0017] Heat treatment: the non-equal wall thickness special-shaped bushing intermediate body subjected to the secondary carbon deposition of the interface layer is taken out from the chemical vapor infiltration device, and an outer mold and a reinforcing frame are installed outside the non-equal wall thickness special-shaped bushing intermediate body. Together with the mold, the non-equal wall thickness special-shaped bushing intermediate body subjected to the secondary carbon deposition of the interface layer is placed into a heat treatment device for heat treatment, until the interface layer is graphitized.

[0018] The silicon carbide matrix deposition includes a first silicon carbide matrix deposition, a second silicon carbide matrix deposition and a third silicon carbide matrix deposition.

[0019] The first silicon carbide matrix deposition: the interface layer graphitized non-equal wall thickness special-shaped sleeve intermediate body is placed in a chemical vapor infiltration equipment together with a mold, the silicon carbide matrix deposition is carried out, and when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a first set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out of the chemical vapor infiltration equipment, and the mold and the reinforcing frame are removed.

[0020] The second silicon carbide matrix deposition: the non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the first set value is placed in the chemical vapor infiltration equipment together with a polygonal inner mold, the second silicon carbide matrix deposition is carried out, and when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a second set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out of the chemical vapor infiltration equipment, and the polygonal inner mold and the inner mold wedge are removed.

[0021] The third silicon carbide matrix deposition: the non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the second set value is placed in the chemical vapor infiltration equipment, the third silicon carbide matrix deposition is carried out, and when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a third set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out of the chemical vapor infiltration equipment.

[0022] The C / SiC composite non-equal wall thickness special-shaped sleeve forming method, the step 4, the interface layer preparation and the silicon carbide matrix deposition, further includes:

[0023] The first interface layer carbon deposition set thickness is 50-100 nm, and the second interface layer carbon deposition set thickness is 100-300 nm.

[0024] The first silicon carbide matrix deposition set value is 1.00-1.20 g / cm 3 , the second silicon carbide matrix deposition set value is 1.30-1.40 g / cm 3 , and the third silicon carbide matrix deposition set value is 1.65-1.80 g / cm 3 .

[0025] The step 6, the final silicon carbide matrix deposition, the non-equal wall thickness special-shaped sleeve density set value is 1.90-2.0 g / cm 3 .

[0026] The C / SiC composite non-equal wall thickness special-shaped sleeve forming method, the step 6, the final silicon carbide matrix deposition, further includes:

[0027] The non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the deposition setting value of the third silicon carbide substrate is placed into a chemical vapor infiltration device to perform final silicon carbide substrate deposition until the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches the product setting value, and then the non-equal wall thickness special-shaped sleeve intermediate body is taken out from the chemical vapor infiltration device to obtain the non-equal wall thickness special-shaped sleeve.

[0028] The C / SiC composite non-equal wall thickness special-shaped sleeve forming method, in the step 1, the tubular preform preparation, the carbon fiber cloth is 3K plain carbon cloth.

[0029] The C / SiC composite non-equal wall thickness special-shaped sleeve forming method, in the step 1, the tubular preform preparation, the wound carbon fiber cloth is 15mm longer than the non-equal wall thickness special-shaped sleeve along the length of the cylindrical inner mold axis.

[0030] A C / SiC composite non-equal wall thickness special-shaped sleeve forming mold, comprising a cylindrical inner mold, a polygonal inner mold, an outer mold, a reinforcing frame, and an inner mold wedge.

[0031] The non-equal wall thickness special-shaped sleeve is cylindrical, the outer surface is a cylindrical surface, the hollow part inside is a regular polygonal prism, the central axis of the regular polygonal prism coincides with the central axis of the outer surface cylindrical surface, and the number of edges of the regular polygonal prism is not less than four.

[0032] The cylindrical inner mold is a cylinder. The polygonal inner mold is composed of two symmetrical parts and is a regular polygonal cylinder, and the cylinder core is a cuboid. The contact surface of the polygonal inner mold and the inner mold wedge (1) is provided with a draft angle. After the main body of the inner mold wedge is inserted and expanded, the bottom surface of the polygonal inner mold is a regular polygon with a circumference equal to that of the bottom surface of the cylindrical inner mold, and the height of the polygonal inner mold is equal to that of the cylindrical inner mold. The inner mold wedge is an integral structure, comprising a main body and an end part. The main body is a cuboid and is provided with a draft angle. The length of the main body is equal to the height of the polygonal inner mold and matches the cylinder core of the polygonal inner mold. The end part is a cylinder, and the cylinder of the end part is used for holding when being inserted and pulled out.

[0033] The outer mold is cylindrical and is composed of two symmetrical parts. The two parts are separated along the central axis, and the height of the outer mold is less than that of the cylindrical inner mold. The reinforcing frame has two parts, which are circular rings. The inner circular surface of the circular ring matches the outer circular surface of the outer mold and is used for clamping the outer mold.

[0034] When the forming mold is used, the cylindrical inner mold is located in the cylinder core of the non-equal wall thickness special-shaped sleeve preform and is in contact with the non-equal wall thickness special-shaped sleeve preform. After the cylindrical inner mold is pulled out, the polygonal inner mold is inserted into the cylinder core of the non-equal wall thickness special-shaped sleeve preform. The outer mold is arranged outside the circumference of the non-equal wall thickness special-shaped sleeve preform. The reinforcing frame is in contact with the outer mold and is located outside the outer mold and matches the outer mold to reinforce the outer mold.

[0035] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming die has the cylindrical inner die, the multi-prism inner die, the outer die, the reinforcing frame and the inner die wedge block all made of high-purity high-strength graphite material.

[0036] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming die has the multi-prism inner die with a die draft angle of 1.5° and the inner die wedge block with a die draft angle of 1.5°. The cylindrical inner die has a radius of 21.6 mm and a height of 60 mm. The outer die has an inner diameter of 57.2 mm and a height of 60 mm.

[0037] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming die has the outer die with a die draft angle of 2°.

[0038] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming die has the outer die with a die draft angle of 2°.

[0039] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming method has the following beneficial effects:

[0040] The C / SiC composite material non-equal wall thickness special-shaped shaft sleeve forming method has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a perspective view of the shaft sleeve prepared by the present application;

[0042] Figure 2 is a top view of the shaft sleeve prepared by the present application;

[0043] Figure 3 is a perspective view of the mold (with the carbon fiber cloth preform);

[0044] Figure 4 is a perspective view of the two-piece multi-prism inner die;

[0045] Figure 5 is a perspective view of the inner die wedge block;

[0046] Figure 6 is a schematic diagram of the shaft sleeve shaping process.

[0047] In the figure: 1. Inner die wedge block, 2. Multi-prism inner die, 3. Carbon fiber cloth preform, 4. Outer die, 5. Reinforcing frame. DETAILED DESCRIPTION

[0048] Example 1

[0049] A forming method of a C / SiC composite non-equal-wall-thickness special-shaped shaft sleeve, comprising the following steps:

[0050] 1) Preparing a non-equal-wall-thickness special-shaped shaft sleeve mold: the mold comprises a cylindrical inner mold, a multi-prism inner mold, an outer mold, a reinforcing frame and an inner mold wedge.

[0051] The cylindrical inner mold, the multi-prism inner mold, the outer mold, the reinforcing frame and the inner mold wedge are high-purity graphite materials.

[0052] 2) Using the winding method to wind the carbon fiber cloth with the center line of the use profile of the cylindrical inner mold as the starting end to the setting thickness of the special-shaped shaft sleeve to form a tubular preform;

[0053] The specification of the carbon fiber cloth is 3K plain carbon cloth.

[0054] The length of the tubular preform L+15mm, L is the length of the corresponding specification non-equal-wall-thickness special-shaped shaft sleeve.

[0055] The bottom circumference of the cylindrical inner mold = the bottom polygonal circumference of the multi-prism inner mold.

[0056] 3) After the preform winding is completed, the mold is closed using two halves of the outer mold with a draft angle, and the reinforcing frame is used for fixation to ensure that the upper and lower end faces of the cylindrical inner mold and the outer mold are flush;

[0057] The inner diameter of the outer mold is d+0.2mm, wherein d is the outer profile diameter of the corresponding specification non-equal-wall-thickness special-shaped shaft sleeve.

[0058] 4) The cylindrical inner mold is extracted;

[0059] 5) The two halves of the multi-prism inner mold with a draft angle are inserted into the carbon fiber preform;

[0060] The draft angle is 1°-2.5°.

[0061] 6) The inner mold wedge with the same draft angle is inserted into the multi-prism inner mold to ensure that the upper and lower end faces of the multi-prism inner mold and the outer mold are flush, so as to prepare the non-equal-wall-thickness special-shaped shaft sleeve preform by means of the ductility and resilience of the carbon fiber cloth;

[0062] 7) The non-equal-wall-thickness special-shaped shaft sleeve preform is subjected to CVI interfacial layer deposition to prepare a non-equal-wall-thickness special-shaped shaft sleeve preform with a carbon interfacial layer, and the thickness of the carbon interfacial layer is 100-300nm;

[0063] 8) The non-equal-wall-thickness special-shaped shaft sleeve preform with a carbon interfacial layer thickness meeting the requirements is subjected to high-temperature treatment.

[0064] 9) CVI silicon carbide matrix deposition on the non-uniform wall thickness special-shaped bushing preform with carbon interface layer to prepare a C / SiC composite non-uniform wall thickness special-shaped bushing preform, the density of the C / SiC composite non-uniform wall thickness special-shaped bushing preform being 1.65-1.80 g / cm 3 ;

[0065] The non-uniform wall thickness special-shaped bushing preform needs to be shaped using a mold during CVI deposition.

[0066] 10) Processing the inner and outer dimensions of the C / SiC composite non-uniform wall thickness special-shaped bushing;

[0067] 11) Continuing CVI silicon carbide matrix deposition on the processed C / SiC composite non-uniform wall thickness special-shaped bushing preform to obtain a continuous fiber reinforced ceramic matrix composite non-uniform wall thickness special-shaped bushing, the density of the continuous fiber reinforced ceramic matrix composite non-uniform wall thickness special-shaped bushing being 1.90-2.0 g / cm 3 ;

[0068] Example 2

[0069] This example is the preparation of a continuous fiber reinforced ceramic matrix composite special-shaped bushing with an outer diameter of 57 mm, a wall thickness of 4.5-6 mm, a height of 60 mm, a cylindrical outer shape, and a polygonal inner shape, and the specific steps are as follows:

[0070] 1) Preparing a non-uniform wall thickness special-shaped bushing mold: the mold includes a cylindrical inner mold, a polygonal inner mold, an outer mold, a reinforcing frame, and an inner mold wedge.

[0071] 2) Using the winding method to wind the 3K carbon fiber cloth with the center line of the use profile of the cylindrical inner mold as the starting end to the shaped thickness of the special-shaped bushing to make a tubular preform; the radius of the cylindrical inner mold is 21.6 mm, and the height of the preform is 75 mm.

[0072] 3) After the preform winding is completed, the two pieces of outer mold with a 2° draft angle are closed, and the reinforcing frame is used for fixation to ensure that the upper and lower end faces of the cylindrical inner mold and the outer mold are flush, and the inner diameter of the outer mold is 57.2 mm;

[0073] 4) The cylindrical inner mold is extracted;

[0074] 5) The two pieces of polygonal inner mold with a 1.5° draft angle are inserted into the carbon fiber preform;

[0075] 6) The inner mold wedge with the same 1.5° draft angle is inserted into the polygonal inner mold to ensure that the upper and lower end faces of the polygonal inner mold and the outer mold are flush, so as to obtain the non-uniform wall thickness special-shaped bushing preform by means of the ductility and resilience of the carbon fiber cloth;

[0076] 7) depositing interface layer of carbon on the non-equal wall thickness special-shaped sleeve preform by CVI to prepare a non-equal wall thickness special-shaped sleeve preform with carbon interface layer, and the thickness of the carbon interface layer is 280 nm;

[0077] 8) high temperature treatment on the non-equal wall thickness special-shaped sleeve preform with carbon interface layer with the required thickness of carbon interface layer.

[0078] 9) depositing silicon carbide matrix on the non-equal wall thickness special-shaped sleeve preform with carbon interface layer by CVI to prepare a C / SiC composite non-equal wall thickness special-shaped sleeve preform, and the density of the C / SiC composite non-equal wall thickness special-shaped sleeve preform is 1.72 g / cm 3 ;

[0079] 10) processing the inner and outer dimensions of the C / SiC composite non-equal wall thickness special-shaped sleeve;

[0080] 11) continuously depositing silicon carbide matrix on the processed C / SiC composite non-equal wall thickness special-shaped sleeve preform by CVI to obtain a continuous fiber reinforced ceramic matrix composite non-equal wall thickness special-shaped sleeve, and the density of the continuous fiber reinforced ceramic matrix composite non-equal wall thickness special-shaped sleeve is 1.95 g / cm 3 .

Claims

1. A forming method of a C / SiC composite material non-equal-wall-thickness special-shaped bushing, characterized in that, The method comprises the following steps: Step 1, preparation of a tubular preform: a carbon fiber cloth is wound on the circumferential surface of a cylindrical inner mold as an axis by using a winding method until the outer diameter of the carbon fiber cloth wound on the cylindrical inner mold is the same as the outer diameter of the special-shaped sleeve preform, so as to obtain a tubular preform wound on the cylindrical inner mold; Step 2, demolding: first, the outer mold is closed, two outer molds (4) are arranged outside the tubular preform, the outer mold (4) is matched with the length of the tubular preform in the axial direction, the outer mold (4) is fixed by using a reinforcing frame (5), and the end face of the non-drawing angle end of the cylindrical inner mold is flush with the end face of the outer mold; second, the cylindrical inner mold is drawn out from the tubular preform, and the cylindrical inner mold is drawn out from the non-drawing angle end; Step 3, mold insertion: first, the multi-prism inner mold (2) is inserted into the tubular preform, the multi-prism inner mold (2) is inserted in the reverse direction of the drawing of the cylindrical inner mold, that is, the multi-prism inner mold (2) is inserted from the drawing angle end of the multi-prism inner mold until the end face of the non-drawing angle end of the multi-prism inner mold (2) is flush with the end face of the tubular preform; second, the inner mold wedge block (1) is inserted into the multi-prism inner mold (2) from the non-drawing angle end of the multi-prism inner mold (2) until the gap between the bottom of the insertion end of the cylindrical inner mold wedge block (1) and the end face of the multi-prism inner mold (2) is less than 0.05 mm, so as to obtain a non-equal-wall-thickness special-shaped sleeve preform with inner and outer molds; Step 4, interface layer preparation and silicon carbide matrix deposition: the non-equal-wall-thickness special-shaped sleeve preform is subjected to interface layer carbon deposition, heat treatment and silicon carbide matrix deposition to obtain a non-equal-wall-thickness special-shaped sleeve intermediate body with a set density; Step 5, mechanical processing: the non-equal-wall-thickness special-shaped sleeve intermediate body obtained in step 4 is subjected to mechanical processing according to the size requirement to obtain a non-equal-wall-thickness special-shaped sleeve intermediate body with a size meeting the requirement; Step 6, final silicon carbide matrix deposition: the non-equal-wall-thickness special-shaped sleeve intermediate body subjected to mechanical processing is subjected to final silicon carbide matrix deposition to obtain a non-equal-wall-thickness special-shaped sleeve with a density reaching the set value of the product.

2. The method according to claim 1, wherein the C / SiC composite non-equal-wall-thickness special-shaped bushing forming method is characterized in that, The step 4, interface layer preparation and silicon carbide matrix deposition, further comprises: The interface layer carbon deposition comprises primary interface layer carbon deposition and secondary interface layer carbon deposition; The primary interface layer carbon deposition: the non-equal-wall-thickness special-shaped sleeve preform is placed into a chemical vapor infiltration device together with a mold for interface layer carbon deposition until the interface layer reaches a set thickness of the primary interface layer carbon deposition, and then the non-equal-wall-thickness special-shaped sleeve preform is taken out from the chemical vapor infiltration device, the outer mold (4) and the reinforcing frame (5) are removed, and a non-equal-wall-thickness special-shaped sleeve intermediate body is obtained; The secondary interface layer carbon deposition: the non-equal-wall-thickness special-shaped sleeve intermediate body subjected to the primary interface layer carbon deposition is placed into the chemical vapor infiltration device together with the multi-prism inner mold (2) for secondary interface layer carbon deposition until the interface layer reaches a set thickness of the secondary interface layer carbon deposition; The heat treatment: the non-equal-wall-thickness special-shaped sleeve intermediate body subjected to the secondary interface layer carbon deposition is taken out from the chemical vapor infiltration device, the outer mold (4) and the reinforcing frame (5) are arranged outside the non-equal-wall-thickness special-shaped sleeve intermediate body, the non-equal-wall-thickness special-shaped sleeve intermediate body subjected to the secondary interface layer carbon deposition is placed into a heat treatment device together with a mold for heat treatment until the interface layer is graphitized; The silicon carbide matrix deposition comprises primary silicon carbide matrix deposition, secondary silicon carbide matrix deposition and tertiary silicon carbide matrix deposition; The first silicon carbide matrix deposition: the interface layer graphitized non-equal wall thickness special-shaped sleeve intermediate body is placed in a chemical vapor infiltration equipment together with a mold, silicon carbide matrix deposition is carried out, when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a first set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out from the chemical vapor infiltration equipment, and the outer mold (4) and the reinforcing frame (5) are removed; The second silicon carbide matrix deposition: the non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the first set value is placed in the chemical vapor infiltration equipment together with the polygonal inner mold (2), the second silicon carbide matrix deposition is carried out, when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a second set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out from the chemical vapor infiltration equipment, and the polygonal inner mold (2) and the inner mold wedge block (1) are removed; The third silicon carbide matrix deposition: the non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the second set value is placed in the chemical vapor infiltration equipment, the third silicon carbide matrix deposition is carried out, when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a third set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out from the chemical vapor infiltration equipment.

3. The method according to claim 2, wherein the C / SiC composite non-equal-wall-thickness special-shaped bushing forming method is characterized in that, The step 4, the interface layer preparation and the silicon carbide matrix deposition, further comprises: The first interface layer carbon deposition set thickness is 50-100 nm, and the second interface layer carbon deposition set thickness is 100-300 nm; The first silicon carbide substrate deposition density set value is 1.00-1.20 g / cm 3 , the second silicon carbide substrate deposition density set value is 1.30-1.40 g / cm 3 , and the third silicon carbide substrate deposition density set value is 1.65-1.80 g / cm 3 . The step 6, the final silicon carbide substrate deposition, the density setting value of the non-equal wall thickness special-shaped shaft sleeve is 1.90~2.0 g / cm 3 .

4. The method according to claim 2, wherein the C / SiC composite non-equal-wall-thickness special-shaped bushing forming method is characterized in that, The step 6, the final silicon carbide matrix deposition, further comprises: The non-equal wall thickness special-shaped sleeve intermediate body with the density reaching the third set value is placed in the chemical vapor infiltration equipment, the final silicon carbide matrix deposition is carried out, when the density of the non-equal wall thickness special-shaped sleeve intermediate body reaches a product set value, the non-equal wall thickness special-shaped sleeve intermediate body is taken out from the chemical vapor infiltration equipment, and the non-equal wall thickness special-shaped sleeve is obtained.

5. The method according to claim 1, wherein the C / SiC composite non-equal-wall-thickness special-shaped bushing forming method is characterized in that, The step 1, the tubular preform preparation, the carbon fiber cloth is 3K plain carbon cloth.

6. The method according to claim 1, wherein the C / SiC composite non-equal-wall-thickness special-shaped bushing forming method is characterized in that, The step 1, the tubular preform preparation, the length of the wound carbon fiber cloth along the axis of the cylindrical inner mold is 15 mm longer than the length of the non-equal wall thickness special-shaped sleeve.

7. A forming die for a C / SiC composite non-constant wall thickness profiled bushing, characterized in that, The cylindrical inner mold, the polygonal inner mold (2), the outer mold (4), the reinforcing frame (5), and the inner mold wedge block (1) are included; The non-equal wall thickness special-shaped sleeve is a cylinder, the outer surface is a cylindrical surface, the hollow part in the interior is a regular polygonal prism, and the central axis of the regular polygonal prism coincides with the central axis of the cylindrical surface of the outer surface; the number of edges of the regular polygonal prism is not less than four; The cylindrical inner mold is a cylinder; the polygonal inner mold (2) is composed of two symmetrical parts and is a regular polygonal cylinder, the cylinder core is a cuboid, and a draft angle is arranged on the contact surface of the inner mold wedge block (1); after the insertion of the inner mold wedge block main body is opened, the bottom surface of the polygonal inner mold (2) is a regular polygon with a circumference equal to the circumference of the bottom surface of the cylindrical inner mold, and the height of the polygonal inner mold is equal to the height of the cylindrical inner mold; the inner mold wedge block (1) is an integral structure including a main body and an end part, the main body is a cuboid, a draft angle is arranged, and the length of the main body is equal to the height of the polygonal inner mold (2) and matches the cylinder core of the polygonal inner mold (2); the end part is a cylinder, and the cylinder of the end part is used for holding during insertion and extraction; The outer mold (4) is cylindrical and consists of two symmetrical parts which are separated along the central axis, and the height of the outer mold is less than that of the cylindrical inner mold; the reinforcing frame (5) is a circular ring which matches the outer surface of the outer mold and is used to clamp the outer mold (4); When the forming mold is used, the cylindrical inner mold is located in the cylinder center of the non-equal-wall-thickness special-shaped shaft sleeve preform and is connected with the non-equal-wall-thickness special-shaped shaft sleeve preform; after the cylindrical inner mold is pulled out, the multi-prism inner mold (2) is inserted into the cylinder center of the non-equal-wall-thickness special-shaped shaft sleeve preform; the outer mold (4) is arranged outside the circumference of the non-equal-wall-thickness special-shaped shaft sleeve preform, the reinforcing frame (5) is connected with the outer mold (4) and is located outside the outer mold and matches the outer mold (4) and is used to reinforce the outer mold (4).

8. The C / SiC composite non-equal-wall-thickness special-shaped bushing forming die according to claim 7, characterized in that, The cylindrical inner mold, the multi-prism inner mold (2), the outer mold (4), the reinforcing frame (5) and the inner mold wedge block (1) are all made of high-purity high-strength graphite material.

9. The C / SiC composite non-equal-wall-thickness special-shaped bushing forming die according to claim 7, characterized in that, The pull-out angle of the multi-prism inner mold (2) is 1.5°, the pull-out angle of the inner mold wedge block (1) is 1.5°, the radius of the cylindrical inner mold is 21.6 mm and the height is 60 mm, the inner diameter of the outer mold (4) is 57.2 mm and the height is 60 mm.

10. The C / SiC composite non-equal-wall-thickness special-shaped bushing forming die according to claim 7, characterized in that, The pull-out angle of the outer mold (4) is 2°.

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