A non-mat short-cut fiber reinforced silicon carbide ceramic matrix composite material and a preparation method thereof

Abstract

The application provides a non-mat short-cut fiber reinforced silicon carbide ceramic composite material and a preparation method thereof. The preparation method of the composite material comprises the following steps: stirring PHPCS resin, silicon carbide and short-cut fibers in an organic solvent for 4-5 hours to obtain a slurry; pouring the slurry into a mold and compacting, and then pre-sintering the slurry under an inert atmosphere at a temperature of 200-700 DEG C for 2-8 hours to obtain a green body; and vacuum hot pressing the green body for 630 minutes, and performing gradient heating and pressure increasing during the vacuum hot pressing process. The application controls the cross-linking degree and viscosity of the slurry, so that the short-cut fibers are uniformly dispersed in the slurry, and the density of the material is improved through repeated normal pressure.

Description

Technical Field

[0001] This invention belongs to the field of ceramic composite materials technology, specifically relating to a silicon carbide ceramic matrix composite material based on non-felt short-cut fiber reinforcement and its preparation method. Background Technology

[0002] Silicon carbide ceramic matrix composites possess irreplaceable application value in key fields such as aerospace, protective equipment, high-temperature structural components, and friction braking due to their advantages including excellent high-temperature stability, low density, high specific strength, and strong thermal shock resistance. However, numerous bottlenecks in existing preparation technologies have long constrained the large-scale promotion and engineering application of these materials.

[0003] Traditional manufacturing routes often use continuous fiber preforms (1D, 2D or 3D fabrics) as the core. Although they can achieve certain performance indicators, they have poor structural design flexibility, making it difficult to adapt to the needs of complex irregular parts. In addition, the manufacturing cycle is long and the equipment requirements are demanding, resulting in high costs for large-scale production.

[0004] To overcome the constraints of continuous fibers, chopped fiber reinforcement processes have been explored both domestically and internationally in recent years. However, in practical engineering applications, chopped fiber reinforcement processes face technical bottlenecks such as difficulty in dispersion, poor density, long production cycles, and shape limitations. Specifically: Short-cut fibers are prone to agglomeration, and there is a general lack of effective rheological control methods, which often leads to problems such as delamination and segregation of fibers during flow and compression. This results in structural defects such as pores, segregation, and weak interfacial connections within the material. In traditional methods, the ceramic matrix often exists in the form of particle packing, making it difficult to achieve sufficient densification during sintering and forming a continuous, dense ceramic network structure, thus significantly limiting the mechanical and thermal properties of the material. Existing short-fiber reinforced CMC preparation generally relies on complex processes such as multiple impregnations, repeated pyrolysis, and long-cycle sintering, making the preparation cycle often several weeks or even months, which seriously restricts large-scale production. At the same time, limited by slurry viscosity, fiber packing state, and molding equipment, existing processes are difficult to prepare high-density complex irregular parts in a short period of time. They are usually only suitable for conventional shapes such as flat plates and blocks, which cannot meet the actual needs of engineering fields for complex and high-performance ceramic matrix composites. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a non-felt short-cut fiber reinforced silicon carbide ceramic matrix composite material and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for preparing a silicon carbide ceramic matrix composite material based on non-felt chopped fiber reinforcement, comprising the following steps: (1) Stir PHPCS resin, silicon carbide and chopped fibers in an organic solvent for 4-5 hours to obtain a slurry; the PHPCS resin is obtained by reacting methyl dichlorosilane and phenyl dichlorosilane in an organic solvent under an inert atmosphere with sodium metal as a coupling agent via Woods reaction and transposition reaction; the organic solvent is any one of toluene, xylene, ethylbenzene, n-hexane and cyclohexane; (2) Pour the slurry into the mold and compact it, then pre-sinter it in an inert atmosphere to obtain the green body; (3) The billet is subjected to vacuum hot pressing sintering, wherein the temperature gradient and pressure gradient are respectively: Temperature gradient: Increase the temperature from room temperature to 290-310℃ at a rate of 3-4℃ / min; increase the temperature from 290-310℃ to 390-410℃ at a rate of 1.5-2.5℃ / min, then continue to increase the temperature from 390-410℃ to 490-510℃ at a rate of 1.5-2.5℃ / min; increase the temperature from 490-510℃ to 990-1010℃ at a rate of 5-6℃ / min and hold for 100 min; then increase the temperature from 990-1010℃ to 1500-1600℃ at a rate of 3-4℃ / min and hold for 100 min. Pressure gradient: When the temperature rises to 290-310℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature rises to 390-410℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature rises to 490-510℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then increased from 0.9-1.1 MPa to 1113 MPa at a rate of 0.1-0.15 MPa / min, then increased from 1113 MPa to 1416 MPa at a rate of 0.025-0.035 MPa / min, and then increased from 1416 MPa to 1921 MPa at a rate of 0.03-0.04 MPa / min and held for 100 minutes.

[0007] In the preparation method of this invention, the purpose of pre-sintering in step (2) is to shape the slurry and allow the PHPCS resin to undergo initial transformation and form a stable porous framework. Then, during the subsequent vacuum hot-pressing sintering process, the matrix particles melt at high temperatures, causing adhesion between particles and reducing defects, thus further densifying the material. Therefore, the specific pre-sintering temperature and time can be determined by those skilled in the art based on the actual shape and size of the prepared silicon carbide ceramic composite material, as long as the slurry is shaped. Preferably, the pre-sintering temperature is 200-700℃ and the time is 7-8 hours.

[0008] Preferably, in step (3), the temperature gradient is as follows: from room temperature to 300℃ at a rate of 3-4℃ / min; from 300℃ to 400℃ at a rate of 1.5-2.5℃ / min; then from 400℃ to 500℃ at a rate of 1.5-2.5℃ / min; from 500℃ to 1000℃ at a rate of 5-6℃ / min; then hold for 100min; then from 1000℃ to 1550℃ at a rate of 3-4℃ / min; and hold for 100min.

[0009] Preferably, the pressure gradient in step (3) is as follows: when the temperature is raised to 300℃, the pressure is increased from 0 to 1MPa within 1 minute, and after holding the pressure for 5 minutes, the pressure is released to 0; when the temperature is raised to 400℃, the pressure is increased from 0 to 1MPa within 1 minute, and after holding the pressure for 5 minutes, the pressure is released to 0; when the temperature is raised to 500℃, the pressure is increased from 0 to 1MPa within 1 minute, and after holding the pressure for 5 minutes, the pressure is increased from 1MPa to 12MPa at a rate of 0.1-0.15MPa / min, then increased from 12MPa to 15MPa at a rate of 0.025-0.035MPa / min, then increased from 15MPa to 20MPa at a rate of 0.03-0.04MPa / min and held for 100 minutes.

[0010] Preferably, step (1) specifically involves mixing PHPCS resin with an organic solvent to obtain a resin solution; then adding silicon carbide and chopped fibers to the resin solution and stirring for 4-5 hours to obtain a slurry.

[0011] Preferably, the mass fraction of PHPCS resin in the resin solution is 30-50%.

[0012] Preferably, the silicon carbide is silicon carbide powder, and its mass does not exceed 30% of the mass of PHPCS resin. Using silicon carbide powder can reduce costs to some extent. Since silicon carbide powder is crystalline and does not possess sintering activity, using more than 30% will affect the overall hardness of the board. Furthermore, excessive silicon carbide powder will cause the slurry to become too viscous, thus affecting the uniform mixing with the chopped fibers.

[0013] Preferably, the mass of the chopped fibers is 10-30% of the mass of the PHPCS resin. More preferably, the mass of the chopped fibers is 25% of the mass of the PHPCS resin. When the amount of chopped fibers is less than 10%, the chopped fibers are difficult to form a continuous stress network, and their effect on enhancing the strength and toughness of the material is negligible, failing to act as a reinforcing phase. When the amount is higher than 30%, the chopped fibers are prone to agglomeration and uneven dispersion in the matrix, which not only reduces the fluidity of the material, leading to difficulties in injection molding and casting, but also reduces the mechanical properties of the material due to stress concentration between fibers, while significantly increasing raw material costs.

[0014] The chopped fibers used in this invention are commonly used chopped fibers for reinforcing ceramic composites, such as chopped carbon fibers, chopped silicon carbide fibers, chopped alumina fibers, and chopped silicon nitride fibers. Preferably, the chopped fibers are chopped carbon fibers or chopped silicon carbide fibers. More preferably, the length of the chopped fibers is 5-10 mm.

[0015] Preferably, the reaction temperature of the Woods reaction in step (1) is 100-120°C, and the reaction time is 7-9 hours. More preferably, the reaction temperature of the Woods reaction is 110°C, and the reaction time is 8 hours.

[0016] Preferably, the reaction temperature of the translocation reaction is 190-210℃ and the reaction time is 3-5h. More preferably, the reaction temperature of the translocation reaction in step (1) is 200℃ and the reaction time is 4h.

[0017] In a second aspect, the present invention provides a non-felt short-fiber reinforced silicon carbide ceramic matrix composite material prepared by the preparation method of the first aspect.

[0018] This application has the following beneficial effects: This invention controls the degree of crosslinking of PHPCS resin in the slurry by controlling the stirring time during slurry preparation, and controls the slurry viscosity within the range of 1.5 to 2.5 Pa·s, so that the slurry exhibits obvious pseudoplastic rheological properties, improves the uniform dispersion of short chopped fibers, and does not exhibit stratification when left to stand, thereby solving the problem of difficult dispersion.

[0019] This invention enables the PHPCS resin precursor to undergo initial transformation and form a stable porous framework through pre-sintering. Then, during vacuum hot pressing, repeated normal pressure application (i.e., rapid pressure increase to 1 MPa followed by pressure decrease) melts the matrix particles at high temperatures, causing adhesion between particles and reducing defects. This further densifies the composite material and promotes fiber interweaving, constructing a network-like reinforcing structure. This achieves multi-directional synergistic load-bearing, significantly improving the overall mechanical properties and resistance to external forces. The preparation process of this invention effectively separates the precursor crosslinking and final densification processes, avoiding early curing that locks in the fiber structure. This significantly reduces porosity, improves fiber / matrix interface bonding, and facilitates one-time molding and high-density fabrication of complex components, thus solving the problems of poor density and shape limitations.

[0020] The vacuum hot pressing process of this invention takes a total of 10.5 hours, which does not require multiple cycles, significantly shortening the cycle and thus solving the problem of long cycle time. Attached Figure Description

[0021] Figure 1 This is a photograph of the actual brake disc in Example 1; Figure 2 This is a physical image of the sphere in Example 2. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the embodiments.

[0023] In the preparation method of the non-felt short-cut fiber reinforced silicon carbide ceramic matrix composite material of the present invention, the entire vacuum hot pressing sintering process in step (3) is 630 min.

[0024] The temperature gradient design during vacuum hot pressing sintering is as follows: within 90 minutes, the temperature rises from room temperature to 290-310℃ at a rate of 33.5℃ / min; within the next 50 minutes, the temperature rises from 290-310℃ to 390-410℃ at a rate of 2.0-2.4℃ / min; within the next 50 minutes, the temperature rises from 390-410℃ to 490-510℃ at a rate of 2.0-2.4℃ / min; within the next 90 minutes, the temperature rises from 490-510℃ to 990-1010℃ at a rate of 5.6-5.8℃ / min, and then holds at 990-1010℃ for 100 minutes; within the next 150 minutes, the temperature rises from 990-1010℃ to 1500-1600℃ at a rate of 3.44℃ / min, and then holds at 1500-1600℃ for 100 minutes.

[0025] Preferably, the temperature gradient is as follows: the temperature is increased from room temperature to 300°C at 90 min; the temperature is further increased from 300°C to 400°C at 140 min; the temperature is further increased from 400°C to 500°C at 190 min; the temperature is further increased from 500°C to 1000°C at 280 min and held at that temperature for 380 min; then the temperature is further increased from 1000°C to 1550°C at 530 min and held at that temperature for 630 min.

[0026] The pressure gradient during vacuum hot pressing sintering is as follows: at 90 min, the pressure is rapidly increased from 0 to 0.9-1.1 MPa (within 1 min), held for 5 min, and then released to 0; at 140 min, the pressure is rapidly increased from 0 to 0.9-1.1 MPa (within 1 min), held for 5 min, and then released to 0; at 190 min, the pressure is rapidly increased from 0 to 0.9-1.1 MPa (within 1 min), held for 5 min, and then increased again; at 280 min, the temperature is raised. At 1000℃, the pressure was increased from 0.9-1.1 MPa to 11-13 MPa at a rate of 0.1-0.14 MPa / min; at 380 min, the pressure was increased from 11-13 MPa to 14-16 MPa at a rate of 0.03-0.05 MPa / min; at 530 min, the pressure was increased from 14-16 MPa to 19-21 MPa at a rate of 0.03-0.04 MPa / min and held at that pressure for 630 min.

[0027] Preferably, the pressure is rapidly increased from 0 to 1 MPa at 90 min (within 1 min), held for 5 min, and then depressurized to 0; the pressure is rapidly increased from 0 to 1 MPa at 140 min (within 1 min), held for 5 min, and then depressurized to 0; the pressure is rapidly increased from 0 to 1 MPa at 190 min (within 1 min), held for 5 min; then the pressure is increased, from 1 MPa to 12 MPa at 280 min, from 12 MPa to 15 MPa at 380 min, and from 15 MPa to 20 MPa at 530 min and held for 630 min.

[0028] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0029] Example 1: In this embodiment, the reinforced silicon carbide ceramic matrix composite material is used for a brake disc, as shown in the physical image below. Figure 1 As shown. The method for manufacturing this brake disc includes the following steps:

[0030] (12) Preparation of PHPCS resin: Under anhydrous and oxygen-free conditions, methyl dichlorosilane and phenyl dichlorosilane (M... 甲基二氯硅烷 M 苯基二氯硅烷 The mixture (100:7) was subjected to a Woods reaction under a nitrogen atmosphere using metallic sodium as a coupling agent and anhydrous toluene as a solvent (reaction temperature 110℃, reaction time 8h). Then, the temperature was raised to 200℃ for a transposition reaction for 4h. The PHPCS resin was obtained by filtration and vacuum distillation.

[0031] (13) Slurry preparation: Dissolve the PHPCS resin obtained in step (1) in anhydrous toluene to prepare a resin solution with a mass fraction of 40%. Then add silicon carbide powder (mass of 30% of the PHPCS resin) to the resin solution and stir for 30 min. Then add short-cut carbon fibers with a length of 10 mm (mass of 25% of the PHPCS resin) and stir for 4.5 h to obtain the slurry.

[0032] (14) Pre-sintering: After the slurry is poured into the mold and compacted with a 20kg platen, it is pre-sintered at 700℃ for 8h under nitrogen protection.

[0033] (15) Vacuum hot pressing: The mold is placed in a vacuum hot pressing furnace and repeatedly subjected to normal pressure. The whole process takes 630 minutes. After cooling and depressurization, the brake disc is obtained.

[0034] The temperature and pressure gradient design for the repeated normal pressure application process is as follows: Temperature gradient: The temperature was increased from room temperature (approximately 25°C) to 300°C at 90 min (heating rate approximately 3.1°C / min); the temperature was further increased from 300°C to 400°C at 140 min (heating rate 2°C / min); the temperature was further increased from 400°C to 500°C at 190 min (heating rate 2°C / min); the temperature was further increased from 500°C to 1000°C at 280 min (heating rate approximately 5.6°C / min) and held for 380 min; then the temperature was further increased from 1000°C to 1550°C at 530 min (heating rate approximately 3.7°C / min) and held for 630 min.

[0035] Pressure gradient: At 90 min, the pressure is rapidly increased from 0 to 1 MPa (within 1 min), held for 5 min, and then reduced to 0; at 140 min, the pressure is rapidly increased from 0 to 1 MPa (within 1 min), held for 5 min, and then reduced to 0; at 190 min, the pressure is rapidly increased from 0 to 1 MPa (within 1 min), held for 5 min; then the pressure is increased, from 1 MPa to 12 MPa at 280 min (increase rate approximately 0.12 MPa / min), from 12 MPa to 15 MPa at 380 min (increase rate approximately 0.03 MPa / min), and from 15 MPa to 20 MPa at 530 min (increase rate approximately 0.033 MPa / min) and held until 630 min.

[0036] Example 2 The difference between this embodiment and Embodiment 1 is that this embodiment prepares a solid sphere, the actual object of which is as follows: Figure 2As shown. In step (2), the mass of silicon carbide powder is 30% of the mass of PHPCS resin, and the chopped fibers are chopped SiC fibers with a length of 5 mm; in step (3), the pre-sintering is sintering and shaping at 200℃ under nitrogen protection, and the pre-sintering time is about 7 hours.

[0037] The density of the sphere in this embodiment is approximately 2.0 g / cm³. ³ It can be used for a long time at a high temperature of 1500℃.

[0038] Comparative Example 1 The difference between this comparative example and Example 1 is that: the pre-sintering in step (3) is not performed, and the vacuum hot pressing process in step (4) is a conventional single pressurization.

[0039] The specific operation is as follows: After the slurry is poured into the mold and compacted, the mold is placed in a vacuum sintering furnace for sintering. The entire process of heating and pressurizing takes 630 minutes. The specific heating and pressurizing rates are as follows: at 50 minutes, the temperature is raised from room temperature to 300℃ and the pressure is raised to 0.5MPa, and then the temperature and pressure are maintained for 90 minutes; then the temperature and pressure are increased, at 200 minutes, the temperature is raised to 600℃ and the pressure is raised to 5MPa; at 290 minutes, the temperature is raised to 1000℃ and the pressure is raised to 10MPa, and then the temperature and pressure are maintained for 120 minutes; then the temperature and pressure are continued, at 510 minutes, the temperature is raised to 1550℃ and the pressure is raised to 20MPa, and then the temperature and pressure are maintained for 120 minutes.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that the pre-sintering in step (3) is not performed, and the vacuum hot pressing process in step (4) is a pressureless atmospheric pressure sintering process.

[0041] The specific operation is as follows: the slurry is injected into the mold, and then sintered at high temperature under normal pressure in a nitrogen atmosphere. The temperature rise process during sintering is as follows: at 100 min, the temperature is raised from room temperature to 1000℃ and held for 120 min, and then the temperature is raised from 1000℃ to 1550℃ at 270 min and held for 120 min.

[0042] Comparative Example 3 The difference between this comparative example and Example 1 is that the stirring time after adding short-cut carbon fibers in step (2) is 3 hours.

[0043] Comparative Example 4 The difference between this comparative example and Example 1 is that the stirring time after adding the chopped fibers in step (2) is 6 hours.

[0044] Test case The composite materials prepared in Example 1 and Comparative Examples 1-4 were subjected to performance tests, and the specific results are shown in the table below.

[0045] Comparative Example 1 uses a conventional single continuous pressurization method. The PHPCS resin precursor undergoes cross-linking and curing in the early stage of heating. There is only one pressurized flow window during the molding process. Once the fiber and matrix are locked, they cannot be rearranged, which easily forms a pore-rich area and a weak interface bonding area, resulting in poor performance.

[0046] Comparative Example 2 uses a conventional pressureless atmospheric sintering process. This process relies entirely on the ceramic transformation and particle sintering of the PHPCS resin precursor to achieve densification. Due to the lack of external pressure, the sintering shrinkage is insufficient and the pores are difficult to expel. Multiple impregnation-pyrolysis cycles are usually required to improve the density. The preparation cycle is long and the final porosity is high, making it difficult to obtain high-performance short fiber reinforced ceramic matrix composites.

[0047] In Comparative Example 3, the stirring time was short, the degree of PHPCS crosslinking was too low, the slurry viscosity was about 0.6 Pa·s, the slurry fluidity was too strong, the short-cut fibers were prone to sedimentation and delamination, and pores and delamination defects were generated during the molding process. After sintering, the shrinkage and porosity increased significantly, and the density and mechanical properties decreased significantly.

[0048] In Comparative Example 4, the stirring time was too long, the degree of cross-linking of PHPCS was too high, the slurry viscosity was about 6.5 Pa·s, the slurry fluidity was poor, the short chopped fibers were difficult to fully wet and disperse, and agglomeration and entanglement were easy to occur. After sintering, the sample showed multiple cracks and poor mechanical properties.

[0049] In Example 1, the brake disc material prepared using the method of the present invention achieved a density of 2.2 g / cm³. 3 The higher density means a more compact internal structure and lower porosity, which helps to improve the material's strength and hardness. In terms of strength, due to the reinforcing effect of chopped fibers and the good bonding between the fibers and the matrix, the material achieves a flexural strength of up to 300 MPa and a compressive strength of up to 380 MPa. At the same time, the material prepared from chopped fibers also possesses excellent high-temperature resistance, capable of withstanding temperatures up to 1500℃ (with a strength retention rate of up to 68% after 2 hours of heat treatment). Furthermore, the material's structure and properties remain stable under high-temperature conditions, without significant deformation, softening, or performance degradation. This makes the material a promising candidate for applications in high-temperature fields such as aerospace and energy.

[0050] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0051] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a non-felt chopped fiber reinforced silicon carbide ceramic matrix composite material, characterized in that, Includes the following steps: (1) Stir PHPCS resin, silicon carbide and chopped fibers in an organic solvent for 4-5 hours to obtain a slurry; the PHPCS resin is obtained by reacting methyl dichlorosilane and phenyl dichlorosilane in an organic solvent under an inert atmosphere with sodium metal as a coupling agent via Woods reaction and transposition reaction; the organic solvent is any one of toluene, xylene, ethylbenzene, n-hexane and cyclohexane; (2) Pour the slurry into the mold, compact it, and then pre-sinter it in an inert atmosphere to obtain the green body; (3) The billet is subjected to vacuum hot pressing sintering, wherein the temperature gradient and pressure gradient are respectively: Temperature gradient: Increase the temperature from room temperature to 290-310℃ at a rate of 3-4℃ / min; increase the temperature from 290-310℃ to 390-410℃ at a rate of 1.5-2.5℃ / min, then continue to increase the temperature from 390-410℃ to 490-510℃ at a rate of 1.5-2.5℃ / min; increase the temperature from 490-510℃ to 990-1010℃ at a rate of 5-6℃ / min and hold for 100 min; then increase the temperature from 990-1010℃ to 1500-1600℃ at a rate of 3-4℃ / min and hold for 100 min. Pressure gradient: When the temperature rises to 290-310℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature rises to 390-410℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature rises to 490-510℃, the pressure is increased from 0 to 0.9-1.1 MPa within 1 minute, held for 5 minutes, and then increased from 0.9-1.1 MPa to 1113 MPa at a rate of 0.1-0.15 MPa / min, then increased from 1113 MPa to 1416 MPa at a rate of 0.025-0.035 MPa / min, and then increased from 1416 MPa to 1921 MPa at a rate of 0.03-0.04 MPa / min and held for 100 minutes.

2. The preparation method according to claim 1, characterized in that, The temperature gradient is as follows: increasing the temperature from room temperature to 300℃ at a rate of 3-4℃ / min; increasing the temperature from 300℃ to 400℃ at a rate of 1.5-2.5℃ / min, then continuing to increase the temperature from 400℃ to 500℃ at a rate of 1.5-2.5℃ / min; increasing the temperature from 500℃ to 1000℃ at a rate of 5-6℃ / min and holding for 100min; then increasing the temperature from 1000℃ to 1550℃ at a rate of 3-4℃ / min and holding for 100min.

3. The preparation method according to claim 1 or 2, characterized in that, The pressure gradient is as follows: when the temperature is raised to 300℃, the pressure is increased from 0 to 1MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature is raised to 400℃, the pressure is increased from 0 to 1MPa within 1 minute, held for 5 minutes, and then released to 0; when the temperature is raised to 500℃, the pressure is increased from 0 to 1MPa within 1 minute, held for 5 minutes, and then the pressure is increased from 1MPa to 12MPa at a rate of 0.1-0.15MPa / min, then increased from 12MPa to 15MPa at a rate of 0.025-0.035MPa / min, and then increased from 15MPa to 20MPa at a rate of 0.03-0.04MPa / min and held for 100 minutes.

4. The preparation method according to claim 1, characterized in that, Step (1) involves mixing PHPCS resin with an organic solvent to obtain a resin solution; then adding silicon carbide and chopped fibers to the resin solution and stirring for 4-5 hours to obtain a slurry.

5. The preparation method according to claim 4, characterized in that, The mass fraction of PHPCS resin in the resin solution is 30-50%.

6. The preparation method according to claim 4 or 5, characterized in that, The silicon carbide is silicon carbide powder, and its mass is no more than 30% of the mass of PHPCS resin.

7. The preparation method according to claim 4 or 5, characterized in that, The mass of the chopped fibers is 10-30% of the mass of the PHPCS resin.

8. The preparation method according to claim 1, characterized in that, The reaction temperature of the Woods reaction in step (1) is 100-120℃ and the reaction time is 7-9h.

9. The preparation method according to claim 1, characterized in that, The reaction temperature of the transposition reaction in step (1) is 190-210℃ and the reaction time is 3-5h.

10. A non-felt chopped fiber reinforced silicon carbide ceramic matrix composite material prepared by the method according to any one of claims 1 to 9.

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