PBO chopped fiber reinforced aluminum-based composite material and preparation method thereof

Abstract

The invention provides a PBO chopped fiber reinforced aluminum matrix composite and a preparation method thereof, and belongs to the technical field of metal matrix composites.The preparation method comprises the steps that firstly, fibers are subjected to ultrasonic dispersion; 2, ball milling and powder mixing; step 3, spark plasma sintering; and 4, follow-up high-temperature annealing is conducted, the prepared PBO chopped fiber reinforced aluminum-based composite material is composed of a PBO chopped fiber reinforced body and an aluminum matrix, the composite material is high in density, the maximum tensile yield strength, the maximum tensile strength and the maximum bending strength all meet the high standard, in addition, the composite material further has the good plastic deformation capacity, and on the whole, the composite material has the good mechanical property. The composite material has outstanding comprehensive mechanical properties. In addition, the preparation process of the composite material is simple, rapid preparation of the PBO chopped fiber reinforced aluminum-based composite material can be achieved, and engineering application of the composite material can be promoted.

Description

Technical Field

[0001] The invention relates to the technical field of metal matrix composite materials, and in particular to a PBO chopped fiber reinforced aluminum matrix composite material and a preparation method thereof. Background Art

[0002] Aluminum-based composite materials are a type of composite material with aluminum or aluminum alloy as the matrix and continuous long fibers, short fibers, whiskers and particles as the reinforcement phase. They have the characteristics of high specific strength, corrosion resistance, low expansion coefficient and low cost. They have broad application prospects in aerospace, automobile, armor protection and other fields.

[0003] At present, the commonly used reinforcement materials for aluminum-based composites mainly include silicon carbide fiber, silicon carbide particles, nanocarbon (such as graphene, carbon nanotubes) and carbon fiber. Among them, the preparation process of silicon carbide fiber, silicon carbide particles and nanocarbon reinforced aluminum-based composites is complicated, the processing is difficult and the cost is high. In addition, carbon fiber has high strength and modulus, and has a significant strengthening effect on the matrix. However, due to the interface reaction between the aluminum matrix and the carbon fiber to generate Al4C3 brittle phase, it has an adverse effect on the comprehensive performance of the aluminum-based composite. Therefore, it is urgent to find new reinforcement materials to prepare aluminum-based composites.

[0004] Therefore, we propose a PBO chopped fiber reinforced aluminum matrix composite material and a preparation method thereof. Summary of the invention

[0005] The present invention aims at the many deficiencies existing in the prior art, and provides a PBO chopped fiber reinforced aluminum-based composite material and a preparation method thereof. The present invention selects PBO fiber. Compared with carbon fiber and silicon carbide fiber, PBO fiber (poly(p-phenylene benzobisoxazole) fiber) has higher strength and modulus, and its tensile strength reaches 5.8GPa, and has better plasticity (elongation after fracture: 3.5%), which is a more ideal reinforcement material. At the same time, PBO fiber has excellent impact resistance, high temperature resistance, friction resistance and dimensional stability. In addition, using PBO fiber as a reinforcement can avoid the reaction between the fiber and the aluminum matrix to generate brittle products during the sintering preparation process. Therefore, compared with carbon fiber, PBO fiber can play its reinforcing role to a greater extent, which is more conducive to improving the comprehensive mechanical properties of aluminum-based composite materials.

[0006] The present invention uses metal aluminum as the matrix in the composite material and uses PBO chopped fibers as the reinforcing fibers in the composite material. The specific preparation process includes ultrasonic dispersion of PBO chopped fibers, ball milling of PBO chopped fibers and aluminum matrix, spark plasma sintering of the mixed material, and annealing treatment, and finally obtains PBO chopped fiber reinforced aluminum-based composite materials. The above combination and production method have simple processes, can realize the rapid preparation of PBO chopped fiber reinforced aluminum-based composite materials, are conducive to promoting the engineering application of the composite material, and the prepared composite material has high strength, good plastic deformation ability, and good comprehensive mechanical properties.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0009] Step 1: First, ultrasonically disperse the PBO chopped fibers using an ultrasonic dispersion device, and then dry the PBO chopped fibers;

[0010] Step 2: The dried PBO chopped fibers and the aluminum matrix are milled and mixed using a three-dimensional planetary vibration ball mill to obtain a mixed material;

[0011] By using a three-dimensional planetary vibration ball mill for ball milling, compared with the conventional planetary ball milling process, the three-dimensional planetary vibration ball milling powder mixing process adds high-frequency vibration in the vertical direction on the basis of planar rotation ball milling, which is more conducive to promoting the full mixing of PBO chopped fibers and aluminum powder matrix, thereby more effectively exerting the reinforcing effect of PBO chopped fibers on the matrix.

[0012] Step 3: placing the mixed material into a cemented carbide mold, and then placing the cemented carbide mold in a spark plasma sintering furnace for sintering. After sintering, demoulding is performed to obtain a PBO chopped fiber reinforced aluminum matrix composite body;

[0013] By adopting the spark plasma sintering process, which is different from conventional hot pressing sintering, the spark plasma sintering process has a fast heating rate, which can greatly shorten the sintering time and improve the sintering efficiency. At the same time, the low temperature and high pressure sintering mode can effectively prevent the damage of PBO chopped fibers and the melting of aluminum matrix caused by excessive sintering temperature.

[0014] Step 4: placing the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing, and cooling the blank to room temperature with the furnace after annealing to obtain the PBO chopped fiber reinforced aluminum-based composite material.

[0015] The reason for performing the above annealing is that the cooling rate after spark plasma sintering is relatively fast, resulting in excessive internal stress in the PBO chopped fiber reinforced aluminum-based composite material after sintering, which can easily have an adverse effect on the mechanical properties of the composite material. Subsequent high-temperature annealing treatment can eliminate the internal stress in the composite material, thereby improving the comprehensive mechanical properties of the composite material.

[0016] Preferably, in the above technical solution, the length of the PBO chopped fibers in step 1 is 1-6 mm.

[0017] Preferably, in the above technical scheme, the ball milling and mixing of powders in the step 2 is specifically carried out according to the following steps: PBO chopped fibers with a mass fraction of 2wt% to 10wt% are mixed with an aluminum matrix and placed in a ball mill, and then alumina ball milling balls are added, and then the ball mill is fixed on a three-dimensional planetary vibration ball mill for ball milling and mixing of powders, and the ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio is (2 to 8): 1, ball milling time is 2 to 8h, and ball milling speed is 200 to 600r / min.

[0018] The main reason for selecting the above amount of PBO chopped fibers is that when the fiber reinforcement content in the composite material is lower than 2wt%, its reinforcing effect on the matrix is ​​limited, and when the fiber reinforcement content is higher than 10wt%, the fibers tend to agglomerate during the ball milling process, resulting in reduced reinforcing effect.

[0019] Preferably, in the above technical scheme, the ball milling and mixing of powders in step 2 are specifically carried out according to the following steps: PBO chopped fibers with a mass fraction of 3wt% to 7wt% are mixed with an aluminum matrix and placed in a ball mill, and then alumina ball milling balls are added, and then the ball mill is fixed on a three-dimensional planetary vibration ball mill for ball milling and mixing of powders. The ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio is (3 to 6): 1, ball milling time is 2 to 8h, and ball milling speed is 200 to 600r / min.

[0020] Preferably, in the above technical solution, the aluminum matrix in step 2 is aluminum powder, and the particle size of the aluminum powder is 20 to 200 μm.

[0021] Preferably, in the above technical solution, the sintering temperature of the sintering treatment in step three is 450-600° C., the sintering pressure is 100-300 MPa, and the heat preservation and pressure holding time is 10-45 min.

[0022] The main reason for selecting the above sintering temperature is that when the sintering temperature is lower than 450°C, the aluminum powder cannot be sintered densely due to the low sintering temperature, and the mechanical properties of the composite material are poor; and when the sintering temperature is higher than 600°C, on the one hand, the aluminum powder softens more and even partially melts, and is easy to flow out of the mold under pressure, resulting in demolding difficulties or even preparation failure. On the other hand, too high a sintering temperature can easily lead to the destruction of the PBO chopped fiber structure, resulting in weakened reinforcement effect on the aluminum matrix.

[0023] Preferably, in the above technical solution, the annealing temperature of the annealing treatment in step 4 is 300-500° C., and the annealing holding time is 1-4 hours.

[0024] The present invention also provides a PBO chopped fiber reinforced aluminum-based composite material, which is prepared by the above method.

[0025] Compared with the prior art, the present invention has the following technical effects:

[0026] The present invention adopts a combination of PBO chopped fibers as reinforcing fibers in a composite material and metal aluminum as a composite material matrix to obtain a new composite material, wherein the PBO chopped fibers have a good reinforcing effect on the aluminum matrix. The prepared PBO chopped fiber reinforced aluminum-based composite material has high density, and its maximum tensile yield strength, maximum tensile strength, and maximum bending strength all have high standards. In addition, the composite material also has good plastic deformation ability. Overall, the composite material has outstanding comprehensive mechanical properties.

[0027] Furthermore, the composite material has low production cost and simple preparation process, and can realize the rapid preparation of PBO chopped fiber reinforced aluminum-based composite materials, which is conducive to promoting the engineering application of the composite material. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations of the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0029] The following detailed description is the description of the embodiments, and is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0030] The PBO chopped fiber reinforced aluminum matrix composite materials prepared in the following examples were tested for density using a JA2003 electronic balance.

[0031] The PBO chopped fiber reinforced aluminum matrix composites prepared in the following examples were subjected to tensile tests using an electronic universal material testing machine (Instron INSTRON 5985, USA).

[0032] The tensile strength, yield strength and elongation of the PBO chopped fiber reinforced aluminum matrix composite materials prepared in the following examples are all measured according to GB / T228-2002 from the tensile stress-strain curve obtained from the tensile test.

[0033] The PBO chopped fiber reinforced aluminum matrix composites prepared in the following examples were subjected to a bending strength test using an electronic universal material testing machine (Instron INSTRON 5985, USA).

[0034] The flexural strength of the PBO chopped fiber reinforced aluminum matrix composite material prepared in the following examples is measured according to GB / T232-2010 “Method for bending test of metal materials”.

[0035] Example 1

[0036] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0037] Step 1: Place 1 mm long PBO chopped fibers in an ultrasonic dispersion device, then add anhydrous ethanol, start the device for ultrasonic dispersion, and then dry the dispersed fibers.

[0038] Step 2: Mix 2wt% of PBO chopped fibers and 20μm aluminum powder into a ball mill, then add alumina ball milling balls, and then fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio of 2:1, ball milling time of 2h, and ball milling speed of 200r / min.

[0039] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 450°C, the sintering pressure is 100 MPa, and the heat preservation and pressure holding time is 10 minutes. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0040] Step 4: Place the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing at a temperature of 300°C and an annealing holding time of 1 hour. After annealing, cool the blank to room temperature with the furnace to obtain a PBO chopped fiber reinforced aluminum-based composite material.

[0041] The PBO chopped fiber reinforced aluminum-based composite material prepared in this embodiment has a density of 99.3%, a tensile yield strength of 215 MPa, a tensile strength of 255 MPa, a flexural strength of 385 MPa, and an elongation after fracture of 16.5%, and has good comprehensive mechanical properties.

[0042] Example 2

[0043] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0044] Step 1: Place 5 mm long PBO chopped fibers in an ultrasonic dispersion device, then add anhydrous ethanol, start the device for ultrasonic dispersion, and then dry the dispersed fibers.

[0045] Step 2: Mix 3wt% of PBO chopped fibers and 60μm aluminum powder into a ball mill, then add alumina ball milling balls, and then fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio of 4:1, ball milling time of 3h, and ball milling speed of 600r / min.

[0046] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 550°C, the sintering pressure is 200MPa, and the heat preservation and pressure holding time is 30min. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0047] Step 4: Place the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing at a temperature of 500°C and an annealing holding time of 2 hours. After annealing, cool the blank to room temperature with the furnace to obtain a PBO chopped fiber reinforced aluminum-based composite material.

[0048] The PBO chopped fiber reinforced aluminum-based composite material prepared in this embodiment has a density of 99.5%, a tensile yield strength of 230 MPa, a tensile strength of 275 MPa, a flexural strength of 405 MPa, and an elongation after fracture of 14.0%, and has good comprehensive mechanical properties.

[0049] Example 3

[0050] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0051] Step 1: Place 6 mm long PBO chopped fibers in an ultrasonic dispersion device, then add anhydrous ethanol, start the device for ultrasonic dispersion, and finally dry the dispersed fibers.

[0052] Step 2: Mix 7wt% of PBO chopped fibers and 200μm aluminum powder into a ball mill, add alumina ball milling balls, and fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are as follows: ball milling ratio of 6:1, ball milling time of 8h, and ball milling speed of 400r / min.

[0053] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 600°C, the sintering pressure is 300MPa, and the heat preservation and pressure holding time is 45min. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0054] Step 4: Place the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing at a temperature of 450°C and an annealing holding time of 4 hours. After annealing, cool the blank to room temperature with the furnace to obtain a PBO chopped fiber reinforced aluminum-based composite material.

[0055] The PBO chopped fiber reinforced aluminum-based composite material prepared in this embodiment has a density of 99.0%, a tensile yield strength of 240 MPa, a tensile strength of 290 MPa, a flexural strength of 420 MPa, and an elongation after fracture of 13.5%, and has good comprehensive mechanical properties.

[0056] Example 4

[0057] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0058] Step 1: Place 4 mm long PBO chopped fibers in an ultrasonic dispersion device, then add anhydrous ethanol, start the device for ultrasonic dispersion, and then dry the dispersed fibers.

[0059] Step 2: Mix 6wt% of PBO chopped fibers and 120μm aluminum powder into a ball mill, add alumina ball milling balls, and fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are as follows: ball milling ratio of 8:1, ball milling time of 6h, and ball milling speed of 300r / min.

[0060] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 475°C, the sintering pressure is 150 MPa, and the heat preservation and pressure holding time is 15 minutes. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0061] Step 4: Place the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing at a temperature of 400°C and an annealing holding time of 3 hours. After annealing, cool the blank to room temperature with the furnace to obtain a PBO chopped fiber reinforced aluminum-based composite material.

[0062] The PBO chopped fiber reinforced aluminum-based composite material prepared in this embodiment has a density of 99.6%, a tensile yield strength of 220 MPa, a tensile strength of 270 MPa, a flexural strength of 400 MPa, and an elongation after fracture of 14.0%, and has good comprehensive mechanical properties.

[0063] Example 5

[0064] The present invention provides a method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps:

[0065] Step 1: Place 5 mm long PBO chopped fibers in an ultrasonic dispersion device, then add anhydrous ethanol, start the device for ultrasonic dispersion, and then dry the dispersed fibers.

[0066] Step 2: Mix 10wt% of PBO chopped fibers and 150μm aluminum powder into a ball mill, add alumina ball milling balls, and fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are as follows: ball milling ratio of 3:1, ball milling time of 5h, and ball milling speed of 500r / min.

[0067] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 575°C, the sintering pressure is 250MPa, and the heat preservation and pressure holding time is 20min. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0068] Step 4: Place the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing at a temperature of 350°C and an annealing holding time of 2 hours. After annealing, cool the blank to room temperature with the furnace to obtain a PBO chopped fiber reinforced aluminum-based composite material.

[0069] The PBO chopped fiber reinforced aluminum-based composite material prepared in this embodiment has a density of 99.3%, a tensile yield strength of 225 MPa, a tensile strength of 280 MPa, a flexural strength of 405 MPa, and an elongation after fracture of 14.5%, and has good comprehensive mechanical properties.

[0070] Comparative Example 1

[0071] The difference from Example 2 is:

[0072] Step 2: Mix 15wt% of PBO chopped fibers and 60μm aluminum powder into a ball mill, add alumina ball milling balls, and fix the ball mill on a three-dimensional planetary vibration ball mill to mix the powders and obtain a mixed material. The ball milling parameters of the three-dimensional planetary vibration ball mill are as follows: ball milling ratio of 4:1, ball milling time of 3h, and ball milling speed of 600r / min.

[0073] The remaining steps are the same as those in Example 2.

[0074] The PBO chopped fiber reinforced aluminum-based composite material prepared in this comparative example has a density of 98.5%, a tensile yield strength of 175 MPa, a tensile strength of 200 MPa, a flexural strength of 355 MPa, and an elongation after fracture of 11.0%.

[0075] By comparing Example 2 with the comparative example, it can be seen that, under the premise that the ball milling process, sintering process and annealing process are the same, due to the excessively high content of PBO chopped fibers, they agglomerate during the ball milling process and cannot be evenly dispersed in the aluminum matrix, resulting in a weakening of their reinforcing effect on the matrix. The yield strength, tensile strength, flexural strength and elongation after fracture of the composite material are significantly reduced, and good comprehensive mechanical properties cannot be achieved.

[0076] Comparative Example 2

[0077] The difference from Example 3 is:

[0078] Step 3: Place the mixed material into a cemented carbide mold, and then place the cemented carbide mold in a spark plasma sintering furnace (SPS) for sintering. The sintering temperature is 700°C, the sintering pressure is 300 MPa, and the heat preservation and pressure holding time is 45 minutes. After sintering, demolding is performed to obtain a PBO chopped fiber reinforced aluminum-based composite material blank.

[0079] The remaining steps are the same as those in Example 3.

[0080] The PBO chopped fiber reinforced aluminum-based composite material prepared in this comparative example has a density of 99.0%, a tensile yield strength of 130 MPa, a tensile strength of 175 MPa, a flexural strength of 280 MPa, and an elongation after fracture of 13.5%.

[0081] By comparing Example 3 with the comparative example, it can be seen that under the premise of the same PBO chopped fiber content, ball milling process, spark plasma sintering pressure, heat preservation and pressure holding time and annealing treatment process, when the sintering temperature is too high, part of the aluminum powder melts and flows into the mold gap, making it difficult to demold after sintering. At the same time, the sintering temperature is too high, causing the PBO chopped fiber structure to be destroyed, and its reinforcing effect on the matrix is ​​weakened or even disappears. The yield strength, tensile strength, flexural strength and elongation after fracture of the composite material are significantly reduced, and good comprehensive mechanical properties cannot be achieved.

[0082] In summary, the present invention uses PBO chopped fibers as reinforcing fibers and metal aluminum as a matrix, and obtains a new composite material through the combination of the two, wherein the PBO chopped fibers have a good reinforcing effect on the aluminum matrix. The density of the composite material formed by the combination of PBO chopped fibers and metal aluminum can reach more than 99.0%, the maximum tensile yield strength can reach 240MPa (pure aluminum yield strength <70MPa), the maximum tensile strength can reach 290MPa (pure aluminum tensile strength <90MPa), and the maximum bending strength can reach 420MPa (pure aluminum bending strength <120MPa). In addition, the composite material has good plastic deformation ability, and its maximum elongation after fracture can reach 16.5%. Overall, the composite material has outstanding comprehensive mechanical properties.

[0083] Furthermore, the preparation process of the composite material firstly uses an ultrasonic dispersing device to disperse the PBO chopped fibers, then puts the PBO chopped fibers and aluminum powder into a ball mill according to a predetermined ratio, and performs mixed ball milling treatment by a three-dimensional planetary vibration ball mill to fully mix and evenly obtain a mixed material; then the mixed material is placed in a cemented carbide mold, and placed in a spark plasma sintering furnace (SPS), and sintered under high temperature and high pressure conditions to obtain a composite material blank, and finally the composite material blank is placed in a vacuum atmosphere sintering furnace for high temperature annealing to obtain a PBO chopped fiber reinforced aluminum-based composite material. The preparation process is simple, can realize the rapid preparation of the PBO chopped fiber reinforced aluminum-based composite material, has a low production cost, and is conducive to promoting the engineering application of the composite material.

[0084] The embodiments described above are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for preparing a PBO chopped fiber reinforced aluminum-based composite material, comprising the following steps: Step 1: Use ultrasonic dispersion equipment to ultrasonically disperse the PBO chopped fibers, and dry the dispersed PBO chopped fibers; Step 2: The dried PBO chopped fibers and the aluminum matrix are milled and mixed using a three-dimensional planetary vibration ball mill to obtain a mixed material; Step 3: placing the mixed material into a cemented carbide mold, and then placing the cemented carbide mold in a spark plasma sintering furnace for sintering. After sintering, demoulding is performed to obtain a PBO chopped fiber reinforced aluminum matrix composite body; Step 4: placing the PBO chopped fiber reinforced aluminum-based composite material blank into a vacuum atmosphere sintering furnace for annealing, and cooling the blank to room temperature with the furnace after annealing to obtain the PBO chopped fiber reinforced aluminum-based composite material.

2. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The length of the PBO chopped fibers in step 1 is 1-6 mm.

3. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The ball milling and powder mixing in step 2 is specifically carried out according to the following steps: PBO chopped fibers with a mass fraction of 2wt% to 10wt% are mixed with an aluminum matrix and placed in a ball mill, and then alumina ball milling balls are added, and then the ball mill is fixed on a three-dimensional planetary vibration ball mill for ball milling and powder mixing. The ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio is (2 to 8): 1, ball milling time is 2 to 8 hours, and ball milling speed is 200 to 600 r / min.

4. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The ball milling and powder mixing in step 2 is specifically carried out according to the following steps: PBO chopped fibers with a mass fraction of 3wt% to 7wt% are mixed with an aluminum matrix and placed in a ball mill, and then alumina ball milling balls are added, and then the ball mill is fixed on a three-dimensional planetary vibration ball mill for ball milling and powder mixing. The ball milling parameters of the three-dimensional planetary vibration ball mill are: ball milling ratio is (3 to 6): 1, ball milling time is 2 to 8h, and ball milling speed is 200 to 600r / min.

5. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The aluminum matrix in the step 2 is aluminum powder, and the particle size of the aluminum powder is 20 to 200 μm.

6. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The sintering temperature of the sintering treatment in the step three is 450-600° C., the sintering pressure is 100-300 MPa, and the heat preservation and pressure holding time is 10-45 minutes.

7. The method for preparing the PBO chopped fiber reinforced aluminum-based composite material according to claim 1, characterized in that: The annealing temperature of the annealing treatment in step 4 is 300-500° C., and the annealing holding time is 1-4 hours.

8. A PBO chopped fiber reinforced aluminum matrix composite material, characterized in that: The composite material is prepared by the method according to any one of claims 1 to 7.