A ceramic matrix composite material with high matrix toughness and preparation method thereof

Abstract

The present invention provides a ceramic-based composite material with high matrix toughness and a preparation method thereof, which relates to the field of composite materials. The embodiment of the present invention is based on a melt infiltration process, wherein a high carbon resin, TiC powder, Al powder and an organic solvent are mixed to obtain a mixed slurry, which is then made into a prepreg with fibers, and then subjected to hot pressing and curing, and a staged carbonization and cracking treatment is adopted to obtain a specific fiber / C porous body; then a staged melt infiltration reaction is adopted, and the melting temperature difference of TiAl and Si is utilized to make TiAl melt preferentially and react with AlN, TiC and C to form a ternary layered phase, while Si powder melts at a higher temperature and reacts with the C porous body to form SiC, thereby obtaining a multi-component toughened SiC. f This method utilizes the layered structure of the MAX phase and the combined effects of multiple components to form multiple fracture energy absorption mechanisms when the composite material is subjected to load, achieving effective toughening of the ceramic matrix composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic-based composite materials, and in particular to a ceramic-based composite material with high matrix toughness and a preparation method thereof. Background Art

[0002] Continuous fiber-reinforced silicon carbide composites (CFRCs) are composites in which reinforcing fibers are introduced into a silicon carbide (SiC) ceramic matrix, forming a composite material with the reinforcing material as the dispersed phase and the ceramic matrix as the continuous phase. These composites exhibit a range of excellent properties, including high-temperature resistance, corrosion resistance, and high strength. However, any structural material, affected by factors such as its preparation and processing, inevitably contains micro-defects within the material, which are the root cause of material failure. The forming process for ceramic-based composites is essentially the same as that for ceramics, but the inherent brittleness of the ceramic matrix hinders the weakening and deflection of defects such as cracks when subjected to load, making brittle fracture more likely. Therefore, to improve the toughness of composites, it is hoped that by modifying the ceramic matrix and increasing its fracture strength, the toughening of the material can be achieved, thereby reducing defects from processing or use, successfully curbing damage, and ultimately extending the service life of the composite.

[0003] Among them, the ternary transition metal compound M n+1 AX n (M: transition metal; A: main group element; X is carbon (C) or nitrogen (N); n = 1-3) possess a hexagonal layered crystal structure. This unique crystal structure imparts unique chemical bonding characteristics, allowing this class of compounds to combine the excellent properties of both metals and ceramics. These compounds exhibit excellent high-temperature performance and can be incorporated into SiC ceramic-matrix composites to enhance their toughness. However, the toughness of existing SiC ceramic-matrix composites containing MAX phases needs to be further improved. Summary of the Invention

[0004] In view of this, the present invention provides a ceramic-based composite material with high matrix toughness and a preparation method thereof. The method of the present invention can achieve effective toughening of the SiC ceramic-based composite material.

[0005] The present invention provides a method for preparing a ceramic-based composite material with high matrix toughness, comprising the following steps:

[0006] S1. Carbonizing and cracking a fiber-reinforced resin preform in nitrogen to obtain a fiber-reinforced carbon-based porous body; the fiber-reinforced carbon-based porous body comprises TiC and AlN;

[0007] S2, Si powder and TiAl powder are subjected to a staged infiltration reaction in the fiber-reinforced carbon-based porous body, wherein the staged infiltration reaction includes a first stage and a second stage, wherein the first stage mainly generates ternary layered phases Ti3AlC2, Ti2AlC and Ti2AlN, and the reaction temperature of the second stage is lower than 1500°C and higher than the reaction temperature of the first stage, wherein the second stage mainly generates SiC to obtain a high-toughness SiC. f / SiC composite materials, in which the ternary layered phases Ti3AlC2, Ti2AlC and Ti2AlN are matrix toughening phases.

[0008] The method of the present invention can effectively achieve toughening of fiber-reinforced silicon carbide ceramic-based composite materials, and is beneficial for application.

[0009] The embodiment of the present invention first provides a fiber-reinforced resin preform, the preparation process of which includes:

[0010] Mixing a binder resin, TiC powder, and Al powder in an organic solvent to obtain a mixed slurry;

[0011] Applying the mixed slurry to the surface of the fiber fabric containing the interface layer to obtain a prepreg;

[0012] The prepreg is hot-pressed and cured to obtain a fiber-reinforced resin preform.

[0013] In an embodiment of the present invention, a bonding resin, TiC powder, Al powder and an organic solvent can be mixed evenly to obtain a mixed slurry, which is then mixed with the reinforcing fiber to form a prepreg, and then hot-pressed and cured to obtain the fiber-reinforced resin preform. The bonding resin in the mixed slurry is a high carbon resin, selected from one or more of phenolic resin, epoxy resin, polyimide resin, furan resin, polyether ketone resin and polytetrafluoroethylene resin. The high carbon resin generally has a residual carbon rate of >50%. The solid content of the bonding resin in some embodiments of the present invention is 70-80%, ensuring good bonding and other effects. The organic solvent can be an alcohol, ester, or ketone, preferably selected from one or more of ethanol, methanol, isopropyl alcohol, acetone, butyl acetate, and ethyl acetate, such as anhydrous ethanol, isopropyl alcohol, butyl acetate, etc.

[0014] In this embodiment of the present invention, TiC and Al are introduced into the slurry to facilitate subsequent modification of the substrate. Specifically, the TiC powder can have a particle size of 2 to 10 μm and a purity of no less than 99.9%; the Al powder has a particle size of 0.2 to 1.0 μm and a purity of no less than 99.99%. Preferably, the mass ratio of the binder resin, TiC powder, and Al powder is 155 to 185:20 to 30:12 to 18; and the mass ratio of the binder resin, organic solvent, TiC powder, and Al powder is (155 to 185):(200 to 240):(20 to 30):(12 to 18).

[0015] In the embodiment of the present invention, the obtained mixed slurry is applied to the surface of a fiber fabric containing an interface layer, and dried to obtain a prepreg; the prepreg is cured by hot pressing to obtain a fiber-reinforced resin preform. Wherein, the fiber fabric containing an interface layer is a SiC fiber fabric containing an interface layer. For the fiber fabric containing an interface layer, the fiber weaving method is selected from unidirectional weaving, 2D weaving, 2.5D weaving or 3D weaving. This application has no special restrictions on the structure and parameters of the interface layer. Furthermore, the temperature of the hot pressing curing is 170 to 250°C, and the time is 1 to 6 hours.

[0016] After obtaining the fiber-reinforced resin preform, the embodiment of the present invention performs a staged carbonization and cracking treatment on it in nitrogen to obtain a carbon-based porous body containing TiC and AlN fibers, which can be recorded as a fiber / C-TiC-AlN porous body. Specifically, the staged carbonization and cracking treatment includes stage one and stage two. The treatment temperature of stage one is 650-720°C, and the heat preservation is 20-60 minutes, wherein the Al melts and reacts with nitrogen to form AlN; the treatment temperature of stage two is 800-1200°C, and the heat preservation is 30-80 minutes. As the temperature rises, the high-carbon resin is completely cracked at a higher temperature, thereby obtaining a fiber / C-TiC-AlN porous body.

[0017] In the embodiments of the present invention, Al is preferentially melted at a lower temperature and then nitrided to form AlN, and the high carbon resin is cracked at a higher temperature. The present invention preferably adopts a staged carbonization and cracking treatment to avoid directly adding AlN to react with the C produced by cracking to form Al, which ultimately prevents the formation of Ti2AlN.

[0018] Subsequently, the embodiment of the present invention mixes Si powder and TiAl powder evenly to obtain a mixed powder, and performs a staged infiltration reaction in the porous body. The infiltration process for preparing ceramic-based composite materials is usually to infiltrate molten silicon into a fiber-reinforced carbon porous body at high temperature, and quickly form a dense matrix through reaction; the process flow generally includes hot pressing, carbonization, and infiltration. The staged infiltration reaction described in the embodiment of the present invention includes: the reaction temperature of the first stage is preferably 1200-1300°C, which can be kept warm for 30-50 minutes. In this stage, TiAl is preferentially melted and infiltrated into the C porous body, and reacts with AlN, TiC, and C to form ternary layered phases Ti3AlC2, Ti2AlC, and Ti2AlN; the reaction temperature of the second stage is preferably 1400-1500°C, which can be kept warm for 10-30 minutes. The temperature in this stage is higher, and the Si powder melts and infiltrates into the C porous body, reacts with C to form SiC, and finally obtains SiC with high matrix toughness toughened by Ti3AlC2, Ti2AlC, and Ti2AlN. f / SiC composite materials.

[0019] In an embodiment of the present invention, the purity of the Si powder is not less than 99.99%; the purity of the TiAl powder is not less than 99.99%. The mass ratio of the Si powder to the TiAl powder is preferably 1:4-6. The Si powder and the TiAl powder are mixed in proportion to form a mixed powder, and then a staged infiltration reaction is carried out in the fiber-reinforced carbon-based porous body to achieve a more uniform reaction. The mass ratio of the Si powder and TiAl powder mixed powder to the fiber-reinforced carbon-based porous body is preferably 1-3:1.

[0020] The embodiment of the present invention mainly utilizes the difference in melting temperatures of TiAl and Si, so that TiAl melts preferentially and reacts with AlN, TiC, and C to form ternary layered phases Ti3AlC2, Ti2AlC, and Ti2AlN, while Si powder melts at a higher temperature and forms SiC with the C porous body, thereby avoiding the system from generating Ti-Si and Si-Al compounds due to Si enrichment and failing to obtain the target layered phase.

[0021] Furthermore, the embodiment of the present invention provides a SiC with high matrix toughness obtained by the preparation method described above. f / SiC composite material; it includes a fiber-reinforced high-toughness SiC matrix, which contains three layered toughening phases of Ti3AlC2, Ti2AlC, and Ti2AlN, which can be called Ti3AlC2, Ti2AlC, Ti2AlN multi-toughened SiC f / SiC composite materials. The volume fraction of the SiC fabric containing the interface layer can be 20%-40%. The embodiments of the present invention utilize an infiltration process to introduce a multi-component toughening phase of Ti3AlC2, Ti2AlC, and Ti2AlN into the SiC matrix through in-situ generation. This results in good compatibility between the matrix and the toughening phase, high interfacial bonding strength, and superior mechanical properties to the resulting ceramic-based composite compared to other infiltration methods.

[0022] The embodiment of the present invention introduces Ti3AlC2, Ti2AlC, and Ti2AlN into the silicon carbide matrix, utilizes the layered structure of the MAX phase itself, and the combined action of multiple components to form multiple fracture energy absorption mechanisms when the silicon carbide composite material is subjected to load, thereby effectively achieving toughening of the ceramic-based composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The examples are SiC before and after multi-component toughening using Ti3AlC2, Ti2AlC, and Ti2AlN. f Stress-strain curves of bending specimens of / SiC composite materials. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0025] To further illustrate the present invention, the following examples are provided. All experimental raw materials in the following examples can be purchased from the market or prepared according to conventional preparation methods known to those skilled in the art. The solid content of the binder resins involved is 70-80%.

[0026] Example 1:

[0027] Step 1: 155 g of phenolic resin, 22 g of TiC powder (2 μm, purity 99.9%), 12 g of Al powder (0.2 μm, purity 99.99%), and 202 g of anhydrous ethanol were mixed to obtain a mixed slurry;

[0028] Step 2: applying the mixed slurry obtained in step 1 to the surface of a unidirectionally woven SiC fiber fabric containing an interface layer, and drying the mixture to obtain a prepreg, wherein the volume fraction of the SiC fabric containing the interface layer is 20%;

[0029] Step 3: hot-pressing and curing the prepreg obtained in step 2 at 180° C. for 6 hours to obtain a SiC fiber-reinforced resin preform;

[0030] Step 4: The SiC fiber reinforced resin preform obtained in step 3 is subjected to a staged carbonization and cracking treatment in a nitrogen atmosphere. Stage 1: 720°C, heat preservation for 20 minutes; stage 2: 800°C, heat preservation for 80 minutes to obtain SiC f / C-TiC-AlN porous body;

[0031] Step 5: Under vacuum conditions, the porous body obtained in step 4 is placed in a mixed powder of Si powder (99.99%) and TiAl powder (99.99%) (mass ratio is 1:4) to carry out a staged infiltration reaction, wherein the mass ratio of the porous body to the mixed powder is 1:1.2. The first stage: 1200℃, heat preservation for 50min; the second stage: 1500℃, heat preservation for 12min, and finally SiC f / SiC-Ti3AlC2-Ti2AlC-Ti2AlN composite material.

[0032] SiC before and after multi-component toughening of Ti3AlC2, Ti2AlC, Ti2AlN f The stress-strain test was conducted on the bending specimens made of / SiC composite materials. Figure 1 . Figure 1In the initial linear elastic stage, the slopes of the two are the same. As the load increases, the untoughened SiC f The matrix cracking stress of the / SiC composite material is low, and the maximum failure stress is about 400MPa; while the toughened SiC f The matrix cracking stress of the / SiC composite material is relatively large, and the maximum failure stress is about 580-590MPa. It can be seen that the toughened SiC f / SiC composite materials have larger fracture strain and show better ability to resist crack propagation.

[0033] Example 2:

[0034] Step 1: 172 g of furan resin, 27 g of TiC powder (7 μm, 99.99% purity), 15 g of Al powder (0.5 μm, 99.99% purity), and 218 g of isopropyl alcohol were mixed to obtain a mixed slurry;

[0035] Step 2: applying the mixed slurry obtained in step 1 to the surface of a 2.5D woven SiC fiber fabric containing an interface layer, and drying the mixture to obtain a prepreg, wherein the volume fraction of the SiC fabric containing the interface layer is 20%;

[0036] Step 3: hot-pressing and curing the prepreg obtained in step 2 at 210° C. for 3 hours to obtain a C fiber reinforced resin preform;

[0037] Step 4: The C fiber reinforced resin preform obtained in step 3 is subjected to a staged carbonization and cracking treatment in a nitrogen atmosphere. Stage 1: 690°C, heat preservation for 30 minutes; stage 2: 900°C, heat preservation for 45 minutes to obtain C f / C-TiC-AlN porous body;

[0038] Step 5: Under vacuum conditions, the porous body obtained in step 4 is placed in a mixed powder of Si powder (99.99%) and TiAl powder (99.999%) (mass ratio is 1:5) to carry out a staged infiltration reaction, wherein the mass ratio of the porous body to the mixed powder is 1:2. The first stage: 1260℃, heat preservation for 40min; the second stage: 1450℃, heat preservation for 20min, and finally SiC f / SiC-Ti3AlC2-Ti2AlC-Ti2AlN composite material.

[0039] Example 3:

[0040] Step 1: 185 g of polyimide resin, 20 g of TiC powder (10 μm, purity 99.9%), 12 g of Al powder (1 μm, purity 99.99%), and 237 g of butyl acetate were mixed to obtain a mixed slurry;

[0041] Step 2: applying the mixed slurry obtained in step 1 to the surface of the SiC fiber fabric containing the interface layer, and drying to obtain a prepreg, wherein the volume fraction of the SiC fabric containing the interface layer is 40%;

[0042] Step 3: hot-pressing and curing the prepreg obtained in step 2 at 247° C. for 1 hour to obtain a SiC fiber-reinforced resin preform;

[0043] Step 4: The SiC fiber reinforced resin preform obtained in step 3 is subjected to a staged carbonization and cracking treatment under nitrogen conditions, stage 1: 650°C, heat preservation for 60 minutes; stage 2: 1200°C, heat preservation for 30 minutes, to obtain SiC f / C-TiC-AlN porous body;

[0044] Step 5: Under vacuum conditions, the porous body obtained in step 4 is placed in a mixed powder of Si powder (99.999%) and TiAl powder (99.99%) (mass ratio is 1:6) to carry out a staged infiltration reaction, wherein the mass ratio of the porous body to the mixed powder is 1:3. The first stage: 1300℃, heat preservation for 30min; the second stage: 1400℃, heat preservation for 30min, and finally SiC f / SiC-Ti3AlC2-Ti2AlC-Ti2AlN composite material.

[0045] Comparative Example

[0046] Single phase toughening, while introducing precursor powders such as TiC into the slurry, we found that during the preparation process, due to the Si-rich system, it is particularly easy to obtain by-product TiSi2, which makes it difficult to achieve a good toughening effect.

[0047] As can be seen from the above examples, the embodiments of the present invention, based on a melt infiltration process, utilize an in-situ generation method to introduce a multi-component toughening phase of Ti3AlC2, Ti2AlC, and Ti2AlN into a SiC matrix. This results in good compatibility between the matrix and the toughening phase, high interfacial bonding strength, and superior mechanical properties of the resulting ceramic-based composite material compared to other introduction methods. The embodiments of the present invention, through the combined action of multiple components and phase structures, form multiple fracture energy absorption mechanisms when the silicon carbide composite material is subjected to load, effectively achieving toughening of the ceramic-based composite material and facilitating its application.

[0048] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the technical solutions and claims of the present invention.

Claims

1. A method for preparing a ceramic matrix composite material with high matrix toughness, characterized in that: The following steps are involved: S1, carbonizing and cracking the fiber-reinforced resin preform in nitrogen to obtain a fiber-reinforced carbon-based porous body; The fiber-reinforced carbon-based porous body comprises TiC and AlN; S2, Si powder and TiAl powder are subjected to a staged infiltration reaction in the fiber-reinforced carbon-based porous body, wherein the staged infiltration reaction includes a first stage and a second stage, wherein the first stage mainly generates ternary layered phases Ti3AlC2, Ti2AlC and Ti2AlN, and the second stage mainly generates SiC, thereby obtaining a high-toughness SiC f / SiC composite material, wherein the ternary layered phases Ti3AlC2, Ti2AlC and Ti2AlN are matrix toughening phases; the mass ratio of the Si powder to the TiAl powder is 1:4-6; the reaction temperature of the first stage of the staged infiltration reaction is 1200-1300°C, and the temperature is kept for 30-50 minutes; the reaction temperature of the second stage is 1400-1500°C, and the temperature is kept for 10-30 minutes; In step S1, the preparation process of the fiber-reinforced resin preform includes: Mixing a binder resin, TiC powder, and Al powder in an organic solvent to obtain a mixed slurry; Applying the mixed slurry to the surface of the fiber fabric containing the interface layer to obtain a prepreg; Hot pressing and curing the prepreg to obtain a fiber-reinforced resin preform; The mass ratio of the bonding resin, TiC powder and Al powder is 155-185:20-30:12-18.

2. The method for preparing a ceramic matrix composite material according to claim 1, wherein: Among the raw materials for preparing the fiber-reinforced resin preform, the bonding resin is one or more of phenolic resin, epoxy resin, polyimide resin, furan resin, polyetherketone resin and polytetrafluoroethylene resin.

3. The method for preparing a ceramic matrix composite material according to claim 1, wherein: In the raw materials for preparing the fiber-reinforced resin preform, the fiber fabric containing the interface layer is SiC fiber fabric; the temperature of the hot pressing curing is 170-250° C., and the time is 1-6 hours.

4. The method for preparing a ceramic matrix composite material according to any one of claims 1 to 3, characterized in that: In step S1, the carbonization and cracking of the fiber-reinforced resin preform in nitrogen is achieved by a staged carbonization and cracking treatment, and the staged carbonization and cracking treatment includes stage one and stage two. The treatment temperature of stage one is 650-720°C, and the heat preservation is 20-60 minutes, wherein Al melts and reacts with nitrogen to form AlN; the treatment temperature of stage two is 800-1200°C, and the heat preservation is 30-80 minutes to obtain a fiber-reinforced carbon-based porous body containing TiC and AlN.

5. The method for preparing a ceramic matrix composite material according to any one of claims 1 to 3, characterized in that: The Si powder and the TiAl powder are mixed to form a mixed powder, and then a staged infiltration reaction is carried out in the fiber-reinforced carbon-based porous body; the mass ratio of the mixed powder to the fiber-reinforced carbon-based porous body is 1 to 3:

1.

6. SiC with high matrix toughness obtained by the preparation method according to any one of claims 1 to 5 f / SiC composite materials.

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