Chopped / continuous alumina fiber synergistically strengthened and toughened alumina-based composite material and preparation method thereof
By introducing short-cut alumina fibers into alumina-based composite materials to form fiber bridging, the problems of low interlaminar shear strength and delamination failure in the thickness direction of existing materials are solved, achieving high-efficiency anti-delamination performance and low-cost preparation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN UNIV OF SCI & TECH
- Filing Date
- 2026-01-09
- Publication Date
- 2026-05-12
AI Technical Summary
Existing alumina fiber-reinforced alumina matrix composites have low interlaminar shear strength in the thickness direction, are prone to delamination failure, and the preparation of three-dimensional fabrics is complex and costly.
A composite material for strengthening alumina matrix by combining short-cut alumina fibers with an alumina matrix was prepared through steps such as high-temperature degumming, ball milling, impregnation-drying-sintering, forming fiber bridging to delay crack propagation.
It improves the anti-delamination properties of composite materials, reduces preparation costs, achieves efficient utilization of fibers, and enhances the thickness direction strength and toughness of materials.
Smart Images
Figure CN122010537A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of continuous ceramic fiber-reinforced ceramic matrix composite material preparation technology, and particularly to a short / continuous alumina fiber synergistic reinforcement alumina matrix composite material and its preparation method. Background Technology
[0002] Continuous alumina fiber-reinforced alumina-based (Al2O3 / Al2O3) composites possess excellent properties such as high temperature resistance, oxidation resistance, high strength, and high toughness, making them an important candidate material for high-temperature components in the aerospace field. Existing commercially available Al2O3 / Al2O3 composites mainly consist of two-dimensional Al2O3 fiber cloth and a porous Al2O3 matrix. The two-dimensional Al2O3 fiber cloth acts as the load-bearing phase, while the porous Al2O3 matrix deflects matrix cracks. Their synergistic effect results in Al2O3 / Al2O3 composites exhibiting not only high toughness but also high strength in the fiber direction. However, due to the high porosity of the matrix and the lack of reinforcing fibers in the thickness direction, cracks first initiate in the matrix during load-bearing processes and then propagate rapidly between the fiber cloth layers. This leads to lower mechanical properties in the thickness direction of the Al2O3 / Al2O3 composites, particularly low anti-delamination performance, making them highly susceptible to delamination failure under interlayer loads.
[0003] Chinese patent document CN113651627A discloses a method for preparing alumina fiber-reinforced alumina ceramic matrix composite material, wherein the shear strength of the composite material is only 6-12 MPa. Chinese patent document CN119874392A discloses a continuous alumina fiber-reinforced alumina-zirconia matrix composite material with excellent comprehensive mechanical / thermal / electrical properties and its preparation method, wherein the interlaminar shear strength of the composite material is 15-17 MPa. In summary, the interlaminar shear strength of two-dimensional Al2O3 / Al2O3 composite materials is below 20 MPa, only 15-20% of the tensile strength in the fiber direction. This low anti-delamination performance severely limits the application of Al2O3 / Al2O3 composite materials in the aerospace field. To improve delamination resistance, reinforcing fibers can be introduced in the thickness direction, forming a three-dimensional fiber fabric-reinforced Al2O3 / Al2O3 composite material. However, certain limitations remain: 1) Due to the high modulus of Al2O3 fibers, they are prone to brittle fracture during the preparation of three-dimensional fiber fabrics using weaving or sewing methods, affecting the mechanical properties of the composite material; 2) Three-dimensional fiber fabrics increase the difficulty of preparing Al2O3 / Al2O3 composite materials, such as low densification efficiency, long preparation cycle, high process cost, and difficulty in molding complex components. For example, Chinese patent document CN112851386A discloses a method for preparing a three-dimensional alumina fiber-woven reinforced alumina composite material, with a flexural strength of 175~339 MPa, lower than that of two-dimensional Al2O3 / Al2O3 composite materials, but does not mention delamination resistance. Therefore, it is urgent to explore a preparation method that can produce Al2O3 / Al2O3 composite materials with high delamination resistance. Summary of the Invention
[0004] To address the above shortcomings, this invention provides a short / continuous alumina fiber synergistic reinforcement alumina matrix composite material and its preparation method, which can improve the interlaminar properties of alumina fiber reinforced alumina matrix composite material and also exhibit excellent anti-delamination ability in the thickness direction. The specific technical solution is as follows: A method for preparing alumina-based composite material with synergistic reinforcement of short / continuous alumina fibers includes the following steps: (1) Prepare short-cut Al2O3 fibers with a length of 0.1~5mm; (2) Fiber degumming: Al2O3 fiber cloth and chopped Al2O3 fibers are subjected to high-temperature heat treatment to remove the adhesive protective layer on their surface; (3) Preparation of slurry: Disperse Al2O3 powder in deionized water, add acidic or alkaline solution, and ball mill to obtain Al2O3 slurry with low solid content for impregnation; disperse Al2O3 powder in deionized water, add acidic or alkaline solution, and ball mill to obtain Al2O3 slurry with high solid content; then add the short-cut Al2O3 fibers obtained in step (1) to the slurry with high solid content, and ball mill to obtain Al2O3 slurry containing short-cut Al2O3 fibers; (4) Preparation of rough blank: Impregnate or brush the Al2O3 slurry containing short-cut Al2O3 fibers from step (3) onto the degummed Al2O3 fiber cloth from step (2), then mold and dry it to form it, and sinter it at high temperature to obtain Al2O3. 3(s,c) / Al2O3 composite material preform; (5) Densification of the rough blank: A low-solid-content Al2O3 slurry is used to densify the Al2O3 obtained in step (4). 3(s,c) The Al2O3 composite preform undergoes subsequent densification, followed by multiple cycles of impregnation, drying, and sintering with Al2O3 slurry. Then, Al2O3 sol is used to further densify the Al2O3. 3(s,c) The Al2O3 composite preform underwent subsequent densification, followed by a multi-cycle impregnation-drying-sintering process with Al2O3 sol, ultimately yielding a short-cut / continuous alumina fiber synergistically strengthened alumina-based composite material (Al2O3). 3(s,c) / Al2O3 composite material).
[0005] The technical solution of this invention is based on the following technical principle: introducing short-cut fibers with small size and large specific surface area into the matrix can generate fiber bridging on the interlaminar crack propagation path, delaying crack propagation, increasing the energy release rate at fracture, and effectively improving the anti-delamination performance of the composite material. Introducing short-cut Al2O3 fibers into a porous Al2O3 matrix forms a short-cut / continuous alumina fiber synergistic strengthening and toughening alumina matrix (Al2O3). 3(s,c) Al2O3 / Al2O3 composite materials can solve the problem of wasted Al2O3 fibers (cloth) generated during the preparation of Al2O3 / Al2O3 composite materials by reusing them in the form of short-cut Al2O3 fibers; on the other hand, they can effectively improve the anti-delamination properties of Al2O3 / Al2O3 composite materials.
[0006] Preferably, in the above preparation method, step (1) specifically involves: cutting Al2O3 fiber bundles or fiber cloth into short Al2O3 fibers, one source of which is: scraps left after trimming the fiber cloth (continuous alumina fibers); sieving and ultrasonically cleaning the short Al2O3 fibers, and then drying them.
[0007] Preferably, in the above preparation method, in step (1), the sieving and washing process of the short-cut Al2O3 fibers is as follows: after passing through a 100-mesh sieve, the residue is placed in an ultrasonic water washer and washed for 0.5 to 2 hours; then, the temperature is raised to 100 to 200°C in the air and kept at that temperature for 0.5 to 2 hours.
[0008] Preferably, in the above preparation method, the degumming process of Al2O3 fiber cloth and chopped Al2O3 fiber in step (2) is as follows: heating to 600-800°C in air for 1-4 hours and holding for 2-4 hours.
[0009] Preferably, in the above preparation method, the acidic solution in step (3) is nitric acid or hydrochloric acid, and the alkaline solution is ammonia. The ball milling process parameters are 300~500 rpm and the ball milling time is 2~4 h.
[0010] Preferably, in the above preparation method, the average particle size (D50) of the Al2O3 powder is 0.15 μm, and the specific surface area is 12.0 m². 2 / g.
[0011] Preferably, in the above preparation method, in step (3), the solid content of the low-solid-content Al2O3 slurry is 20~40 vol.%, and its viscosity is 20~100 mPa·s; in the Al2O3 slurry containing chopped Al2O3 fibers, the content of chopped Al2O3 fibers is 0.5~5.0 wt.%, and the solid content of the Al2O3 slurry containing chopped Al2O3 fibers is 50~55 vol.%, and its viscosity is 500~1000 mPa·s. When the chopped fiber content is too low, the performance of the composite material cannot be effectively improved; when the chopped fiber content is too high, the slurry viscosity will be too high, which is not conducive to the dispersion of chopped fibers and also not conducive to the molding of the composite material.
[0012] Preferably, in the above preparation method, in step (4), Al2O 3(s,c) The drying process of the Al2O3 composite preform is as follows: heat to 100-200°C in air for 0.5-2 hours and hold for 2-6 hours.
[0013] Preferably, in the above preparation method, in step (4), Al2O 3(s,c) The high-temperature sintering process of the Al2O3 composite material blank is as follows: heat to 1100~1400℃ in air for 2~6h, hold for 0.5~2.0h, and cool to room temperature for 2~6h.
[0014] Preferably, in the above preparation method, in step (5), the vacuum pressure during the impregnation process of the low solid content Al2O3 slurry is -0.1MPa, and the impregnation time is 4~8h; the drying process is: heating to 150~250°C in air for 1~4h, and holding for 1~4h; the high temperature sintering process is: heating to 600~1200°C in air for 1~4h, holding for 0.5~2.0h, and cooling to room temperature for 2~4h.
[0015] Preferably, in the above preparation method, in step (5), the vacuum pressure during the impregnation of Al2O3 sol is -0.1MPa and the impregnation time is 4~8h; the drying process is: heating to 150~250°C in air for 1~4h and holding for 1~4h; the high-temperature sintering process is: heating to 600~1200°C in air for 1~4h, holding for 0.5~2.0h, and cooling to room temperature for 2~4h.
[0016] Preferably, the above-mentioned Al2O 3(s,c) In the preparation method of Al2O3 composite material, in step (5), the number of impregnation-drying-sintering cycles of Al2O3 slurry with low solid content and the number of impregnation-drying-sintering cycles of Al2O3 sol are both 2 to 5 times.
[0017] On the other hand, the present invention also provides a short-cut / continuous alumina fiber synergistically strengthening alumina-based composite material, which is prepared by the above-described preparation method.
[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention toughens alumina fiber-reinforced alumina matrix composites by introducing short-cut alumina fibers, resulting in excellent mechanical properties not only in the fiber direction but also in the thickness direction, thus improving the interlaminar properties of the composite material. It eliminates the need for weaving or sewing to prepare three-dimensional fabrics, achieving interlaminar reinforcement on two-dimensional fabric-lay composites and avoiding the problem of delamination failure during service.
[0019] 2. The short-cut Al2O3 fibers introduced in this invention are obtained by cutting Al2O3 fiber bundles (cloth). They are not only easy to obtain and do not require the preparation of three-dimensional fabrics, thus reducing the preparation cost, but also solve the problem of resource waste caused by Al2O3 fiber bundles (cloth) during use.
[0020] 3. The geometric characteristics of the short-cut Al2O3 fibers introduced in this invention are between those of granules and continuous fibers. They not only have excellent mechanical properties similar to those of continuous Al2O3 fibers, but also have excellent characteristics such as small size, large specific surface area, and good wettability, and can be uniformly dispersed in aqueous Al2O3 slurry.
[0021] 4. This invention prepares a highly stable Al2O3 slurry containing chopped Al2O3 fibers, which is applied to Al2O3 / Al2O3 composites to achieve uniform distribution of chopped Al2O3 fibers in the Al2O3 matrix. The chopped Al2O3 fibers can create fiber bridging along the crack propagation path in the interlaminar matrix, delaying crack propagation and increasing the energy release rate at fracture, thereby effectively improving the anti-delamination properties of the composite material. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 Al2O in Embodiment 1 of the present invention 3(s,c) Optical photograph of Al2O3 composite material.
[0024] Figure 2 Al2O in Embodiment 1 of the present invention 3(s,c) Flexural strength-displacement curves of Al2O3 composite materials.
[0025] Figure 3 Al2O in Embodiment 1 of the present invention 3(s,c) Interlaminar shear stress-displacement curves of Al2O3 composite materials.
[0026] Figure 4 Al2O in Embodiment 1 of the present invention 3(s,c) Microstructure of Al2O3 composite material.
[0027] Figure 5 Al2O in Embodiment 1 of the present invention 3(s,c) Microstructure of the fracture surface of Al2O3 composite material. Detailed Implementation
[0028] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in the present invention are commercially available or can be prepared by existing methods.
[0029] Example 1 A method for preparing alumina-based composite material synergistically strengthened and toughened by short / continuous alumina fibers includes the following steps: (1) Preparation of short fibers: Al2O3 fiber bundles (cloth) are cut into short Al2O3 fibers with a length of 2 mm, passed through a 100-mesh sieve, ultrasonically washed for 0.5 h, and then treated in a drying oven at 150 ℃ for 1.5 h; (2) Fiber degumming: Place the Al2O3 fiber cloth and chopped Al2O3 fibers together in a muffle furnace, heat to 700℃, keep warm for 2.0h, and then take them out after cooling to room temperature in the furnace to complete the degumming of the Al2O3 fiber cloth and chopped Al2O3 fibers. (3) Preparation of slurry: Al2O3 powder (average particle size of 0.15 μm) was dispersed in deionized water at a volume ratio of 40 vol%, nitric acid was added, and the mixture was ball-milled at a ball milling rate of 400 r / min for 2.0 h to obtain an Al2O3 slurry with a solid content of 40 vol% and a viscosity of 32 mPa·s; Al2O3 powder (average particle size of 0.15 μm) was dispersed in deionized water at a volume ratio of 53 vol%, nitric acid was added, and the mixture was ball-milled at a ball milling rate of 400 r / min for 2.0 h to obtain a stable Al2O3 slurry with a volume ratio of 53 vol%; then, the short-cut fibers prepared in step (2) were added to the 53 vol% Al2O3 slurry at a volume ratio of 2 wt.% of the total mass of the slurry, and the mixture was ball-milled at 400 r / min for 2.0 h to obtain an Al2O3 slurry containing short-cut fibers with a viscosity of approximately 840 mPa·s; (4) Preparation of rough blank: The Al2O3 fiber cloth obtained in step (2) is impregnated with the Al2O3 slurry containing short-cut fibers obtained in step (3), molded and formed, and then placed in a drying oven, heated to 150℃ and held for 6.0h; then high-temperature sintering is carried out, the specific process is: heated to 1200℃ in air for 2h, held for 0.5h, and cooled to room temperature for 3h to obtain Al2O3. 3(s,c) / Al2O3 composite material preform; (5) Densification of the rough blank: First, the Al2O obtained in step (4) is densified. 3(s,c) The Al2O3 composite preform was placed in a vacuum impregnation tank and impregnated with an Al2O3 slurry with a solid content of 40 vol% for 6.0 h, followed by heating to 200 °C in air and drying for 2.0 h; then the Al2O3... 3(s,c) The Al2O3 composite preform was placed in a muffle furnace and heated to 1100°C in air at a rate of 10.0°C / min, held at that temperature for 0.5 h, and cooled to room temperature for 2 h. This Al2O3 slurry impregnation-drying-sintering process was repeated three times. Next, the Al2O3 composite preform was further impregnated with an Al2O3 sol with a solid content of 40 vol%. 3(s,c)The Al2O3 composite preform underwent subsequent densification, vacuum impregnation for 4.0 h, followed by air heating to 150 °C and drying for 1.0 h; then Al2O3 was... 3(s,c) The Al2O3 composite preform was placed in a muffle furnace and heated to 1100°C in air at a rate of 10.0°C / min, held at that temperature for 0.5 h, and then cooled to room temperature for 2 h. This Al2O3 sol impregnation-drying-sintering process was repeated three times to obtain Al2O3 composite preforms. 3(s,c) / Al2O3 composite material.
[0030] The test standard for the flexural properties of the composite materials in the examples and comparative examples is DIN EN 658-3, and the sample size is 2.7mm × 8.6mm × 51.0mm; the test standard for the interlaminar shear strength is BS EN 658:5-2002, and the sample size is 2.7mm × 10.0mm × 24.0mm.
[0031] Figure 1 Al2O prepared in this embodiment 3(s,c) / Optical photograph of Al2O3 composite material Figure 4 and Figure 5 Al2O prepared in this embodiment 3(s,c) The microstructure and fracture morphology of the Al2O3 composite material are shown in the figure. It can be seen from the figure that short-cut fibers are dispersed between the fiber cloth in the composite material. Table 1 shows the Al2O3 composite material prepared in this example. 3(s,c) The mechanical properties of Al2O3 composite materials are shown in the table. 3(s,c) / Al2O3 composites exhibit high flexural strength, interlaminar shear strength, and fracture toughness.
[0032] Table 1. Al2O2 prepared in Example 1 3(s,c) Main performance parameters of Al2O3 composite materials Example 2 A method for preparing a short / continuous alumina fiber synergistically reinforced and toughened alumina-based composite material includes the following steps: (1) Preparation of short fibers: Cut Al2O3 fiber bundles (cloth) into short Al2O3 fibers with a length of 4 mm, pass them through a 200-mesh sieve, and then ultrasonically wash them for 1 hour, and then treat them in a drying oven at 200℃ for 2 hours. (2) Fiber degumming: Place the Al2O3 fiber cloth and chopped Al2O3 fibers together in a muffle furnace, heat to 700℃, keep warm for 2.0h, and then take them out after cooling to room temperature in the furnace to complete the degumming of the Al2O3 fiber cloth and chopped Al2O3 fibers. (3) Preparation of slurry: Al2O3 powder (average particle size of 0.15 μm) was dispersed in deionized water at a volume ratio of 40 vol%, nitric acid was added, and the mixture was ball-milled at a ball milling rate of 400 r / min for 2.0 h to obtain an Al2O3 slurry with a solid content of 40 vol% and a viscosity of 48 mPa·s; Al2O3 powder (average particle size of 0.15 μm) was dispersed in deionized water at a volume ratio of 50 vol%, nitric acid was added, and the mixture was ball-milled at a ball milling rate of 300 r / min for 3.0 h to obtain a stable Al2O3 slurry with a volume ratio of 50 vol%; then, the short-cut fibers prepared in step (2) were added to the above 50 vol% Al2O3 slurry at a volume ratio of 3 wt.% of the total mass of the slurry, and the mixture was ball-milled at 300 r / min for 3.0 h to obtain an Al2O3 slurry containing short-cut fibers with a viscosity of about 682 mPa·s; (4) Preparation of rough blank: The Al2O3 fiber cloth obtained in step (2) is laid in the mold in sequence, and the Al2O3 slurry obtained in step (3) is evenly coated on the surface of each layer of Al2O3 fiber cloth. After mold closing and molding, it is formed and then placed in a drying oven, heated to 150℃ and held for 6.0h. Then, high-temperature sintering is carried out. The specific process is as follows: the temperature is raised to 1100℃ in air for 1h, held for 0.5h, and cooled to room temperature for 3h to obtain Al2O3. 3(s,c) / Al2O3 composite material preform; (5) Densification of the rough blank: First, the Al2O obtained in step (4) is densified. 3(s,c) The Al2O3 composite material was placed in a vacuum impregnation tank and impregnated with an Al2O3 slurry with a solid content of 40 vol% for 4.0 h, followed by heating to 150 °C in air and drying for 1.0 h; then the Al2O3... 3(s,c) The Al2O3 composite preform was placed in a muffle furnace and heated to 700°C in air at a rate of 10.0°C / min, held at that temperature for 0.5 h, and cooled to room temperature for 2 h. This Al2O3 slurry impregnation-drying-sintering process was repeated three times. Then, Al2O3 sol impregnation was used to further impregnate the Al2O3 composite preform. 3(s,c) The Al2O3 composite preform underwent subsequent densification, vacuum impregnation for 4.0 h, followed by air heating to 150 °C and drying for 1.0 h; then Al2O3 was... 3(s,c) The Al2O3 composite preform was placed in a muffle furnace and heated to 700°C in air at a rate of 10.0°C / min, held at that temperature for 0.5 h, and then cooled to room temperature for 2 h. This Al2O3 sol impregnation-drying-sintering process was repeated three times to obtain Al2O3 composite preforms. 3(s,c) / Al2O3 composite material.
[0033] Table 2 shows the Al2O2 prepared in this embodiment. 3(s,c)Mechanical properties of Al2O3 composite materials. The table shows that Al2O3... 3(s,c) / Al2O3 composites exhibit high flexural strength, interlaminar shear strength, and fracture toughness.
[0034] Table 2 Al2O prepared in Example 2 3(s,c) Main performance parameters of Al2O3 composite materials Comparative Example 1 The difference between this comparative example and Example 1 is that in step (3) Al2O3 slurry, Al2O3 powder is used to replace the short-cut fibers, while other steps and parameters are the same as in Example 1.
[0035] Table 3 shows the mechanical properties of the Al2O3 / Al2O3 composite material prepared in this comparative example. As can be seen from Tables 1 to 3, the flexural strength, flexural modulus, interlaminar shear strength, and fracture toughness of the composite material in this comparative example are significantly lower than those in Example 1 and Example 2.
[0036] Table 3. Main performance parameters of the Al2O3 / Al2O3 composite material prepared in Comparative Example 1 The Al2O3 / Al2O3 composite material in this comparative example exhibits a significant decrease in mechanical properties compared to Example 1. In contrast, the present invention, by introducing short-cut fibers into the interlaminar layers, can significantly improve the interlaminar shear strength, enhance the anti-delamination ability of the two-dimensional Al2O3 / Al2O3 composite material, and further effectively deflect cracks, dissipate fracture energy, and make Al2O3... 3(s,c) The Al2O3 composite material can maintain excellent fracture toughness while being strengthened and toughened.
[0037] In summary, introducing short-cut Al2O3 fibers into a porous Al2O3 matrix can form Al2O3... 3(s,c) Al2O3 / Al2O3 composite materials, while ensuring high mechanical properties in the fiber direction, significantly improve the anti-delamination properties of composite materials, which will strongly promote the engineering application of Al2O3 / Al2O3 composite materials.
[0038] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. A method for preparing a short / continuous alumina fiber synergistically strengthening and toughening alumina-based composite material, characterized in that, Includes the following steps: (1) Prepare short-cut Al2O3 fibers with a length of 0.1~5 mm; (2) Fiber degumming: The Al2O3 fiber cloth and chopped Al2O3 fibers are subjected to high-temperature heat treatment to remove the adhesive protective layer on their surface; (3) Preparation of slurry: Disperse Al2O3 powder in deionized water, add acidic or alkaline solution, and ball mill to obtain Al2O3 slurry with low solid content; disperse Al2O3 powder in deionized water, add acidic or alkaline solution, and ball mill to obtain Al2O3 slurry with high solid content; then add the short-cut Al2O3 fibers obtained in step (1) to the Al2O3 slurry with high solid content, and ball mill to obtain Al2O3 slurry containing short-cut Al2O3 fibers; (4) Preparation of rough blank: Impregnate or brush the Al2O3 slurry containing short-cut Al2O3 fibers from step (3) onto the degummed Al2O3 fiber cloth from step (2), then mold and dry it to form it, and sinter it at high temperature to obtain Al2O3. 3(s,c) / Al2O3 composite material preform; (5) Densification of the rough blank: A low-solid-content Al2O3 slurry is used to densify the Al2O3 obtained in step (4). 3(s,c) The Al2O3 composite preform undergoes subsequent densification, followed by multiple cycles of impregnation, drying, and sintering with Al2O3 slurry. Then, Al2O3 sol is used to further densify the Al2O3. 3(s,c) The Al2O3 composite preform was densified in the later stage, and then subjected to multiple cycles of Al2O3 sol impregnation-drying-sintering treatment to finally obtain alumina-based composite material with synergistic strengthening of short-cut / continuous alumina fibers.
2. The preparation method according to claim 1, characterized in that, The specific steps (1) are as follows: cutting the Al2O3 fiber bundle (cloth) into short Al2O3 fibers; sieving and ultrasonically cleaning the short Al2O3 fibers, and then drying them.
3. The preparation method according to claim 1, characterized in that, In step (3), the average particle size of the Al2O3 powder is 0.15 μm, and the specific surface area is 12.0 m². 2 / g; the solid content of low solid content Al2O3 slurry is 20~40 vol.%, and its viscosity is 20~100 mPa·s; the content of short-cut Al2O3 fibers in Al2O3 slurry is 0.5~5.0 wt.%, the solid content of Al2O3 slurry containing short-cut Al2O3 fibers is 50~55 vol.%, and the viscosity is 500~1000 mPa·s.
4. The preparation method according to claim 1, characterized in that, In step (3), the acidic solution is nitric acid or hydrochloric acid, and the alkaline solution is ammonia; the ball milling process parameters are 300~500 rpm and the ball milling time is 2~4h.
5. The preparation method according to claim 1, characterized in that, In step (4), Al2O 3(s,c) The drying process of the Al2O3 composite preform is as follows: heat to 100-200°C in air for 0.5-2 hours and hold for 2-6 hours.
6. The preparation method according to claim 1, characterized in that, In step (4), Al2O 3(s,c) The high-temperature sintering process of the Al2O3 composite material blank is as follows: heat to 1100~1400℃ in air for 2~6h, hold for 0.5~2.0h, and cool to room temperature for 2~6h.
7. The preparation method according to claim 1, characterized in that, In step (5), the vacuum pressure during the impregnation process of the low solid content Al2O3 slurry is -0.1MPa, and the impregnation time is 4~8h; the drying process is: heating to 150~250°C in air for 1~4h, and holding for 1~4h. The high-temperature sintering process is as follows: the temperature is raised to 600-1200℃ in air for 1-4 hours, held for 0.5-2.0 hours, and then cooled to room temperature for 2-4 hours.
8. The preparation method according to claim 1, characterized in that, In step (5), the vacuum pressure during the impregnation of Al2O3 sol is -0.1MPa and the impregnation time is 4~8h; the drying process is: heating to 150~250°C in air for 1~4h and holding for 1~4h. The high-temperature sintering process is as follows: the temperature is raised to 600-1200℃ in air for 1-4 hours, held for 0.5-2.0 hours, and then cooled to room temperature for 2-4 hours.
9. The preparation method according to claim 1, characterized in that, In step (5), the number of impregnation-drying-sintering cycles for the low solid content Al2O3 slurry and the number of impregnation-drying-sintering cycles for the Al2O3 sol are both 2 to 5.
10. A short / continuous alumina fiber synergistically strengthening and toughening alumina-based composite material, characterized in that, The composite material is prepared by the preparation method according to any one of claims 1 to 9.