Silicon carbide particle aluminum-based composite material and preparation method thereof

Abstract

The embodiment of the invention provides a silicon carbide particle aluminum-based composite material and a preparation method thereof, and the preparation method comprises the following steps: (X1) carrying out wet ball milling, dispersion and drying on aluminum powder and silicon carbide particles with preset volume fractions to obtain silicon carbide particle aluminum-based composite powder, clockwise rotation ball milling and anticlockwise rotation ball milling are alternately carried out, and rotation is stopped during alternation; and (X2) the silicon carbide particle aluminum-based composite powder obtained in the step (X1) is subjected to vacuum sintering, gradient heating is conducted in the vacuum sintering process, and the silicon carbide particle aluminum-based composite material is obtained. By means of the preparation method, the silicon carbide particle aluminum-based composite material which is good in interface bonding, high in density and good in thermal physical performance can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of material preparation, and particularly to a silicon carbide particle aluminum matrix composite material and a preparation method thereof. Background Art

[0002] With the increasingly diversified and complex development of aerospace and electronic devices, the requirements for material properties are becoming more and more stringent. Materials with high thermal conductivity, low expansion coefficient and high strength play a crucial role in ensuring the reliability and service life of satellite structural components. To meet the needs of fields such as aerospace and electronic devices, silicon carbide particle aluminum matrix composite materials have become important candidate materials in the fields of aerospace equipment and electronic packaging due to their excellent comprehensive properties. Silicon carbide particles are widely used to improve the thermal conductivity of aluminum matrix composites due to their excellent high-temperature stability and high thermal conductivity. However, although silicon carbide particles can effectively improve the thermal conductivity and thermal expansion resistance of aluminum matrix composites, affected by the properties of silicon carbide and aluminum itself, the mechanical and thermal properties of the overall material are affected during the preparation process of the composite material.

[0003] In summary, there is an urgent need to develop a new type of aluminum matrix composite material to meet the requirements for high-performance materials in fields such as high-power density electronic devices and aerospace equipment. Summary of the Invention

[0004] Therefore, based on the deficiencies of the prior art, the embodiments of the present invention provide a silicon carbide particle aluminum matrix composite material and a preparation method thereof to prepare a silicon carbide particle aluminum matrix composite material with good interfacial bonding, high density and good thermophysical properties.

[0005] The embodiments of the present invention provide a preparation method of a silicon carbide particle aluminum matrix composite material, including the steps of:

[0006] (X1) Wet ball milling, dispersing and drying aluminum powder and silicon carbide particles with preset volume fractions respectively to obtain a silicon carbide particle aluminum matrix composite powder. The wet ball milling specifically includes alternately rotating the ball mill clockwise and counterclockwise and stopping during the alternation.

[0007] (X2) Vacuum sintering the silicon carbide particle aluminum matrix composite powder obtained in the step (X1), and performing gradient heating during the vacuum sintering to obtain a silicon carbide particle aluminum matrix composite material.

[0008] In some embodiments, the step (X2) specifically includes:

[0009] (X21) First-stage heating: raising the temperature to 300°C - 400°C at a heating rate of 6°C / min - 10°C / min.

[0010] (X22) First-stage heat preservation: 10 min to 30 min;

[0011] (X23) Second-stage temperature rise: Continuously raise the temperature to 500°C to 600°C at a rate of 8°C / min to 10°C / min;

[0012] (X24) Second-stage heat preservation: Heat preservation for 1 h to 3 h;

[0013] (X25) End the heating and perform cooling.

[0014] In some embodiments, the step (X2) further includes:

[0015] In the step (X23), apply a pressure of 20 MPa to 25 Mpa to the silicon carbide particle aluminum-based composite powder, and during the temperature rise process, increase the pressure applied to the silicon carbide particle aluminum-based composite powder to 50 MPa to 55 MPa at a rate of 1 MPa / min to 1.5 MPa / min;

[0016] In the step (X25), when cooling to a temperature of 400°C, stop applying pressure to the silicon carbide particle aluminum-based composite powder, and then continue to cool down.

[0017] In some embodiments, the step (X1) specifically includes:

[0018] (X11) Wet ball mill aluminum powder and silicon carbide particles with a preset volume fraction ratio under a protective atmosphere to obtain a composite powder. The wet ball milling specifically includes alternately performing clockwise rotation ball milling and counterclockwise rotation ball milling, and stopping during the alternation;

[0019] (X12) Place the composite powder obtained in the step (X11) in a protective atmosphere for ultrasonic dispersion to obtain a dispersed composite powder;

[0020] (X13) Place the dispersed composite powder obtained in the step (X12) in a vacuum environment for drying treatment to obtain the silicon carbide particle aluminum-based composite powder.

[0021] In some embodiments, the duration of each clockwise rotation ball milling and each counterclockwise rotation ball milling in the step (X11) is 3 min to 5 min respectively; the stop time during the alternation is 1 min to 2 min, and the total time of the wet ball milling is 6 h.

[0022] In some embodiments, the average particle size of the aluminum powder in the step (X11) is 25 μm to 30 μm; the average particle size of the silicon carbide particles is 250 μm to 300 μm.

[0023] In some embodiments, the preset volume fraction ratio of the aluminum powder to the silicon carbide particles is 10-11:10-9.

[0024] In some embodiments, in the step (X13), the initial temperature in the drying treatment is 30°C - 40°C, and the temperature is increased at a rate of 5°C - 8°C every 2h - 4h until the temperature reaches 50°C - 60°C, and then dried for 24h - 48h.

[0025] The embodiment of the present application also provides a silicon carbide particle aluminum matrix composite material, including the silicon carbide particle aluminum matrix composite material prepared by using the preparation method of the silicon carbide particle aluminum matrix composite material described in any one of the above.

[0026] In some embodiments, the density of the silicon carbide particle aluminum matrix composite material is greater than or equal to 98.5%, the thermal conductivity is 220W / m·K - 250W / m·K, and the coefficient of thermal expansion is 5.8×10 -6 ·K -1 ~14.0×10 -6 ·K -1 。

[0027] The embodiments of the present invention at least include the following beneficial effects: By wet ball milling, dispersing, and drying aluminum powder and silicon carbide particles, the embodiments of the present invention prepare a highly active silicon carbide particle aluminum matrix composite powder, and then further perform vacuum sintering with gradient temperature increase on the silicon carbide particle aluminum matrix composite powder. This not only ensures the stable distribution of silicon carbide particles in the aluminum matrix but also effectively improves the thermophysical properties and mechanical properties of the composite material, enhances its overall performance, and significantly improves the comprehensive performance of the silicon carbide particle aluminum matrix composite material. The wet ball milling method provided by the present invention can disperse and break up cluster particles, evenly distribute silicon carbide particles in the aluminum matrix powder, and improve the material uniformity; it is also beneficial to make the temperature distribution of the material more uniform, thereby reducing the risk of cracks or deformation caused by excessive temperature difference between the surface and the inside of the material; it is also beneficial to reduce material deformation and stress concentration; thus, a silicon carbide particle aluminum matrix composite material with good interfacial bonding, high density, and good thermophysical properties can be obtained through the preparation method of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic flow chart of a preparation method of a silicon carbide particle aluminum matrix composite material provided by an embodiment of the present invention.

[0029] Figure 2 is Figure 1 a specific flow chart of step X1 in the preparation method of the silicon carbide particle aluminum matrix composite material shown.

[0030] Figure 3 is Figure 1Schematic diagram of the specific process of step X2 of the preparation method of the silicon carbide particle aluminum matrix composite material shown.

[0031] Figure 4 Original morphology diagram of the aluminum powder used in Example 1.

[0032] Figure 5 Original morphology diagram of the silicon carbide particles used in Example 1.

[0033] Figure 6 Morphology diagram of the aluminum powder and silicon carbide particles used in Example 1 after wet ball milling.

[0034] Figure 7 Scanning electron microscope image of the silicon carbide particle aluminum matrix composite material prepared by the method of Example 1.

[0035] Figure 8 Scanning electron microscope image of the silicon carbide particle aluminum matrix composite material prepared by the method of Example 2.

[0036] Figure 9 Scanning electron microscope image of the silicon carbide particle aluminum matrix composite material prepared by the method of Example 3.

[0037] Figure 10 Scanning electron microscope image of the silicon carbide particle aluminum matrix composite material prepared by the method of Example 4.

[0038] Figure 11 Scanning electron microscope image of the silicon carbide particle aluminum matrix composite material prepared by the method of Example 5. Detailed implementation manners

[0039] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings.

[0040] In order to enable those of ordinary skill in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0042] It should also be noted that the division of multiple embodiments in the present invention is only for the convenience of description and should not constitute a special limitation. The features in various embodiments can be combined and referenced to each other without conflict.

[0043] Due to its excellent high-temperature stability and high thermal conductivity, silicon carbide particles are widely used to improve the thermal conductivity of aluminum matrix composites, and silicon carbide particles can effectively improve the thermal conductivity and thermal expansion resistance of aluminum matrix composites. Because of its excellent comprehensive performance, it has become an important candidate material in the fields of aerospace equipment and electronic packaging. However, the low interfacial wettability of silicon carbide particles limits the further improvement of the composite material. The interfacial bonding between silicon carbide and the aluminum matrix is weak, which easily leads to an increase in interfacial thermal resistance and affects the mechanical and thermal properties of the composite material.

[0044] Based on the above technical problems, referring to Figure 1 , the embodiments of the present invention provide a preparation method of a silicon carbide particle aluminum matrix composite material, comprising the steps of:

[0045] Step X1: Wet ball mill, disperse and dry aluminum powder and silicon carbide particles with preset volume fractions respectively to obtain silicon carbide particle aluminum matrix composite powder. The wet ball milling specifically includes alternately rotating the ball mill clockwise and counterclockwise and stopping during the alternation.

[0046] Step X2: Vacuum sinter the silicon carbide particle aluminum matrix composite powder obtained in Step X1, and perform gradient heating during the vacuum sintering process to obtain the silicon carbide particle aluminum matrix composite material.

[0047] In step X1, aluminum powder and silicon carbide particles are incorporated into the liquid medium of wet ball milling to perform wet ball milling, which helps to reduce the contact of aluminum powder and silicon carbide particles with oxygen during the wet ball milling process, thereby reducing the oxygen content of the obtained aluminum-based composite powder of silicon carbide particles and making the aluminum-based composite powder of silicon carbide particles highly active. The ball milling process can effectively refine the size of silicon carbide particles, enhance the contact area between silicon carbide particles and the aluminum matrix, improve the uniformity of particle distribution, and avoid the phenomenon of particle aggregation or uneven distribution, thus helping to improve the thermophysical properties and mechanical properties of the composite material. During the ball milling process, the reduction of particle size not only enhances the interfacial activity of the particles but also improves the interfacial bonding force between silicon carbide particles and the aluminum matrix, contributing to higher density and more uniform microstructure during the subsequent sintering process.

[0048] During the wet ball milling process, stopping and rotating alternately is beneficial to reducing the probability of overheating, reducing the excessive wear of the composite powder, and improving the mixing effect. First, the friction between the ball milling medium and the composite powder in wet ball milling generates heat. Therefore, if the ball milling continues, the temperature of the ball milling medium and the powder may rise, leading to sintering of the powder or excessive particle deformation. Therefore, stopping and rotating alternately between clockwise ball milling and counterclockwise ball milling helps to cool the ball milling medium, aluminum powder, and silicon carbide particles, reducing the probability of degradation of the composite powder material caused by overheating. Second, when stopping and rotating, the contact between the ball milling medium and the composite powder decreases, which is beneficial to reducing the excessive wear of the composite powder and the refinement of the composite powder. If directly reversed, it may cause unnecessary wear of the composite powder, thereby affecting the particle size and distribution of the composite powder. Then, during the stopping and rotating process, the relative movement between the composite powder and the ball milling medium slows down, which helps to redistribute the particles in the composite powder and promote full contact and uniform mixing between the particles of the composite powder.

[0049] In step X2, vacuum sintering causes the aluminum matrix composite powder of silicon carbide particles to sinter into an aluminum matrix composite material of silicon carbide particles. During the sintering process, maintaining a vacuum sintering environment is beneficial for reducing the introduction of oxygen during sintering, thereby reducing the adverse effects of impurity atoms on sintering during the process; at the same time, the gas in the micropores of the formed aluminum matrix composite material of silicon carbide particles is excluded, accelerating the densification process of the material, and thus improving the overall performance of the aluminum matrix composite material of silicon carbide particles. During the sintering process, by controlling the sintering temperature and pressure, it is possible to effectively avoid over-sintering of the composite powder, so as to avoid excessive interfacial reactions and ensure the densification and uniformity of the composite material. Reasonably controlling the sintering process can achieve a high density at a relatively low temperature, reduce the generation of pores, and further improve the thermal conductivity and mechanical properties of the composite material. At the same time, the sintering process can also promote the interfacial bonding between the aluminum matrix and the silicon carbide particles, enhancing the overall stability of the composite material. Moreover, vacuum sintering is carried out in a gradient heating manner, which is beneficial for making the temperature distribution of the material more uniform, reducing the risk of cracks or deformation caused by too large a temperature difference between the surface and the inside of the material; at the same time, it is also beneficial for reducing material deformation and stress concentration, and then beneficial for improving the densification and thermophysical properties of the aluminum matrix composite material of silicon carbide particles. At the same time, using the vacuum sintering process also helps to reduce the complexity of the preparation process and reduce the preparation cost.

[0050] In the embodiment of the present invention, by wet ball milling, dispersing, and drying aluminum powder and silicon carbide particles, a highly active aluminum matrix composite powder of silicon carbide particles is prepared, and then the aluminum matrix composite powder of silicon carbide particles is subjected to vacuum sintering with gradient heating. This can not only ensure the stable distribution of silicon carbide particles in the aluminum matrix, but also effectively improve the thermophysical properties and mechanical properties of the composite material, enhance its overall performance, and significantly improve the comprehensive performance of the aluminum matrix composite material of silicon carbide particles; the wet ball milling method provided by the present invention can disperse and break up cluster particles, evenly distribute the silicon carbide particles in the aluminum matrix powder, and improve the material uniformity; it is also beneficial for making the temperature distribution of the material more uniform, thereby reducing the risk of cracks or deformation caused by too large a temperature difference between the surface and the inside of the material; it is also beneficial for reducing material deformation and stress concentration; thus, an aluminum matrix composite material of silicon carbide particles with good interfacial bonding, high densification, and good thermophysical properties can be obtained through the preparation method of the embodiment of the present invention.

[0051] In some specific embodiments, in step X2, the silicon carbide particle aluminum matrix composite powder is placed in a mold, so that the silicon carbide particle aluminum matrix composite powder can be sintered to form a silicon carbide particle aluminum matrix composite material with a specific shape. Specifically, take out the inner lining, punch and gasket of the graphite mold, and spray boron nitride release agent on the inner wall of the inner lining and the surfaces of the punch and gasket in contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the inner lining, punch and gasket into the graphite mold. Take out a small amount of composite powder and fill it into the inner lining of the graphite mold, and the filling amount is 1 / 3 of the volume of the inner lining. After filling, sintering is carried out.

[0052] Specifically, referring to Figure 3 , step X2 specifically includes:

[0053] Step X21: Heating in the first stage: Raise the temperature to 300°C - 400°C at a heating rate of 6°C / min - 10°C / min;

[0054] Step X22: Insulation in the first stage: 10 min - 30 min;

[0055] Step X23: Heating in the second stage: Continue to raise the temperature to 500°C - 600°C at a rate of 8°C / min - 10°C / min;

[0056] Step X24: Insulation in the second stage: Insulate for 1 h - 3 h;

[0057] Step X25: End heating and carry out cooling.

[0058] It can be understood that steps X21 - X25 are sub-steps of step X2.

[0059] By controlling the sintering temperature and time, excessive interfacial reactions are avoided, and excessive sintering of particles is effectively avoided. At the same time, the physical bonding strength between the silicon carbide particles and the aluminum matrix is improved. By optimizing the sintering process, such as the sintering time, etc., the density of the composite material can be increased, the porosity can be reduced, and the density and thermophysical properties of the composite material can be improved.

[0060] Furthermore, step X2 also includes:

[0061] In step (X23), apply a pressure of 20 MPa - 25 Mpa to the silicon carbide particle aluminum matrix composite powder, and during the heating process, increase the pressure applied to the silicon carbide particle aluminum matrix composite powder from 1 MPa / min - 1.5 MPa / min to 50 MPa - 55 MPa.

[0062] Applying pressure can significantly improve the density of the material, reduce the porosity, improve the uniformity of particle distribution, effectively avoid particle agglomeration, and thus enable the composite material to have a more uniform microstructure. Secondly, applying pressure can also effectively improve the mechanical properties of the composite material, including tensile strength, hardness and toughness, because higher density and stronger interfacial bonding significantly reduce the failure risk caused by stress concentration and weak bonding regions. On the other hand, the action of pressure also has a positive impact on the thermal conductivity performance. By reducing the pore and interface thermal resistance and enhancing the continuity of the heat conduction path between particles, the thermal conductivity of the composite material is improved. In addition, applying pressure can also shorten the sintering time, reduce the sintering temperature, improve the dimensional accuracy and stability of the composite material. By controlling the pressure during vacuum sintering, it is also possible to effectively avoid over-sintering of the composite powder.

[0063] In some embodiments, referring to Figure 2 , step (X1) specifically includes:

[0064] Step X11: Wet ball mill aluminum powder and silicon carbide particles with a preset volume fraction ratio under a protective atmosphere to obtain a composite powder. The wet ball milling specifically includes alternately rotating the ball mill clockwise and counterclockwise and stopping during the alternation;

[0065] Step X12: Place the composite powder obtained in step X11 in a protective atmosphere for ultrasonic dispersion to obtain a dispersed composite powder;

[0066] Step X13: Place the dispersed composite powder obtained in step X12 in a vacuum environment for drying treatment to obtain an aluminum matrix composite powder with silicon carbide particles.

[0067] The purity of the aluminum powder and silicon carbide particles used in step X11 is greater than or equal to 99.95%. By alternately rotating the ball mill clockwise and counterclockwise in step X11, the average particle size of the obtained composite powder can be reduced, and the agglomeration of the composite powder can be reduced, increasing the dispersibility of the composite powder.

[0068] In step X12, after wet ball milling in step X11, the composite powder is mixed with the liquid medium added in the wet ball milling to form a liquid medium slurry, and the liquid medium slurry is ultrasonically dispersed to improve the dispersibility of the composite powder in the liquid medium.

[0069] In steps X11 and X12, both wet ball milling and ultrasonic dispersion are carried out in a protective atmosphere to reduce the oxidation of the composite powder, reduce the possibility of an increase in the oxygen content in the composite powder, and maintain the high activity of the composite powder.

[0070] Specifically, a protective atmosphere is formed using high-purity argon gas. Specifically, the environment where wet ball milling is performed is evacuated, and then high-purity argon gas is filled until the pressure in the environment where wet ball milling is performed is the same as the external air pressure. The above operations are repeated at least twice; the environment where ultrasonic dispersion is performed is evacuated, and then high-purity argon gas is filled until the pressure in the environment where the composite powder is dispersed is the same as the external air pressure. The above operations are repeated at least twice.

[0071] Step X13, drying is carried out in a vacuum environment to accelerate the evaporation rate of the liquid medium in wet ball milling, thereby reducing the drying time and improving the drying efficiency; at the same time, it can also reduce the oxygen content in the environment, thereby reducing the probability of oxidation of the silicon carbide particle aluminum matrix composite powder, which is beneficial to maintaining the high activity of the silicon carbide particle aluminum matrix composite powder.

[0072] In this way, the obtained silicon carbide particle aluminum matrix composite powder has the properties of low agglomeration, high activity, low oxygen content, and uniform particle size. These properties enable the silicon carbide particle aluminum matrix composite powder to effectively reduce the sintering temperature during vacuum sintering in step X2, and improve the density and thermophysical properties of the silicon carbide particle aluminum matrix composite material.

[0073] In some embodiments, the average particle size of the aluminum powder in step X11 is 25 μm to 30 μm; the average particle size of the silicon carbide particles is 250 μm to 300 μm. In this way, the silicon carbide particles can be evenly dispersed in the aluminum powder. If the particle size of the silicon carbide particles is too large, it will lead to insufficient crushing of the aluminum powder and silicon carbide particles during the ball milling process, and it is difficult to obtain finer aluminum powder. If the particle size of the silicon carbide particles is too small, the introduced oxygen will also increase, and it is difficult to obtain a silicon carbide particle aluminum matrix composite powder with low oxygen content, which is not conducive to maintaining the high activity of the silicon carbide particle aluminum matrix composite powder. Therefore, using aluminum powder and silicon carbide particles with the above-mentioned particle sizes helps to prepare a silicon carbide particle aluminum matrix composite powder with low agglomeration, high activity, low oxygen content, and uniform particle size.

[0074] Specifically, in step X1, the morphology of the aluminum powder particles is spherical. Spherical aluminum powder particles have good fluidity and uniformity, which can promote the dispersibility during the mixing process. In embodiments where a mold is used for sintering, the spherical aluminum powder particles can more easily fill the mold, which helps to reduce the generation of pores or defects in the obtained silicon carbide particle aluminum matrix composite material; the morphology of the silicon carbide particles is irregular. Irregular silicon carbide particles have a larger contact area, which is beneficial to enhancing their interfacial bonding ability with the aluminum matrix during vacuum sintering, and the irregular silicon carbide particles are cheap, which is beneficial to reducing the cost of preparing the silicon carbide particle aluminum matrix composite material.

[0075] In some embodiments, the preset volume fraction ratio of aluminum powder to silicon carbide particles is 10 - 11:10 - 9. When the volume fraction of silicon carbide particles is low, it is difficult to significantly improve the thermophysical and mechanical properties of the composite material. At low volume fractions, the silicon carbide particles are sparsely distributed in the aluminum matrix and cannot form an effective heat conduction network. The overall thermal conductivity is still mainly dominated by the aluminum matrix, and the improvement amplitude is limited. At the same time, the distance between the silicon carbide particles is large, and heat transfer depends more on the aluminum matrix, making it difficult to fully utilize the high thermal conductivity of the silicon carbide particles. In addition, due to the insufficient proportion of silicon carbide particles, the inhibitory effect on the thermal expansion coefficient of the aluminum matrix is small, and the overall thermal expansion coefficient of the composite material decreases limitedly. In terms of mechanical properties, the low volume fraction results in the inability of silicon carbide particles to form a continuous stress transfer network, and the enhancement effect on the strength and rigidity of the composite material is insufficient. When the volume fraction of the reinforcement phase is high, although the reinforcement effect of the composite material will theoretically continue to increase, other problems are likely to occur. A high volume fraction easily leads to an increase in particle contact, and it is difficult for the matrix aluminum to completely fill the gaps, thus forming pores, significantly increasing the interfacial thermal resistance and reducing the thermal conductivity of the composite material. At the same time, the particles are prone to agglomeration at high volume fractions and are unevenly distributed, resulting in local stress concentration and reducing the strength and fracture toughness of the composite material. In addition, the fluidity of the material significantly decreases at high volume fractions, increasing the difficulty of the preparation process (such as vacuum sintering), and thus it is difficult to make the particles evenly distributed and achieve high density. Therefore, choosing the volume fraction ratio in this embodiment is the result of a comprehensive balance of thermophysical properties, mechanical properties, and process adaptability. Within this range, the composite material can have excellent thermal conductivity, low thermal expansion coefficient, and good mechanical properties, while ensuring the operability of the preparation process and the uniformity of the material. Thus, the preset volume fraction ratio of aluminum powder to silicon carbide particles of 10 - 11:10 - 9 is beneficial to balancing thermophysical properties, mechanical properties, and process adaptability, enabling the composite material to have excellent thermal conductivity, low thermal expansion coefficient, good mechanical properties, and good uniformity, while ensuring the operability of the preparation process. Thus, it is beneficial for the silicon carbide particle aluminum matrix composite powder to be evenly dispersed during hot pressing sintering, thereby improving the uniformity and overall performance of the composite material. In addition, by adjusting the ratio between the silicon carbide particles and the aluminum powder, the thermal properties of the silicon carbide particle aluminum matrix composite material can be adjusted to meet the requirements of different application scenarios.

[0076] In some specific embodiments, the duration of each clockwise rotation and each counterclockwise rotation of the ball milling in step X11 is 3 min to 5 min respectively; the stop time during the alternation is 1 min to 2 min, and the total time of wet ball milling is 6 h. The time of single ball milling does not exceed 5 min, which is beneficial to reducing the probability of phenomena such as agglomeration, combination and excessive cold welding of the composite powder, and reducing the influence on the crushing effect of aluminum powder and silicon carbide particles; the time of single ball milling is greater than or equal to 2 min, so that the aluminum powder and silicon carbide particles can be fully ball milled to obtain a composite powder with a smaller particle size.

[0077] The stop time of the ball milling during the alternation is 1 min to 2 min, which helps to fully promote the mixing and distribution of aluminum powder and silicon carbide particles, and is beneficial to effectively reducing the heat generated during the ball milling process; at the same time, it can also reduce the unnecessary refinement of the composite powder, reduce the probability of agglomeration, and reduce wear, and helps the ball milling to reach the required motion state again and maintain the ball milling efficiency. When the stop time of the ball milling is less than one minute, it is difficult to fully promote the mixing and distribution of aluminum powder and silicon carbide particles, resulting in poor uniformity of the composite powder, and at the same time, it may be difficult to effectively reduce the temperature during the ball milling process, thus making it difficult to reduce the overheating problem. When the stop time of the ball milling is higher than two minutes, it will cause the composite powder to be exposed in a static state for a long time, which may lead to unnecessary refinement of the composite powder, agglomeration or greater wear, and it may take a long time to reach the required motion state again during the re-rotation, thus reducing the efficiency.

[0078] In some embodiments, in step X1, the rotation speed of the ball milling is 100 rpm to 150 rpm, which is beneficial to the uniform dispersion of silicon carbide particles with low oxygen content, and at the same time makes the particle size of aluminum powder smaller. If the rotation speed of the ball milling is too low, the particle size of the composite powder will increase and the activity will decrease; if the rotation speed of the ball milling is too high, the wear of the ball milling tank will be aggravated, and at the same time the particle size of the silicon carbide particles will decrease, resulting in an increase in the oxygen content in the obtained composite powder.

[0079] In some specific embodiments, the ball-to-material ratio of the ball milling is 2 to 3:1. In this way, it helps to improve the wear effect of aluminum powder and silicon carbide particles during the ball milling process. A higher ball-to-material ratio can increase the number of impacts between the ball milling medium and the composite during the grinding process, and promote the refinement and uniform distribution of the composite powder; at the same time, the maximum value of the ball-to-material ratio is limited to reduce the probability of excessive grinding making the particles too fine, so as to be beneficial to maintaining the high activity of the silicon carbide particle aluminum matrix composite powder.

[0080] In some embodiments, in step X11, the liquid medium for wet ball milling is absolute ethanol. By using absolute ethanol, the composite powder can be further separated from the external environment to further prevent the oxidation of the composite powder; ethanol is volatile and can take away part of the heat of the composite powder during the wet ball milling process; and when using absolute ethanol, it is convenient to dry the composite powder.

[0081] In some embodiments, in step X12, the time for ultrasonic dispersion is 1 h to 4 h to ensure that the slurry formed by the liquid medium for ball milling and the composite powder can be fully dispersed.

[0082] In some embodiments, in step X13, the initial temperature in the drying process is 30°C to 40°C, and the temperature is increased at a rate of 5°C to 8°C every 2 h to 4 h until the temperature reaches 50°C to 60°C, and then dried for 24 h to 48 h. In this way, by gradually increasing the temperature during the drying process, the temperature distribution of the composite powder can be made more uniform, the stress concentration of the composite powder can be reduced, and the drying effect can be improved. Gradually increasing the temperature during the drying process is beneficial to reducing the sharp change in the surface and internal temperature of the composite powder, helping to reduce the accumulation of internal stress caused by uneven temperature during the drying process, and reducing the possibility of deformation or rupture of the composite powder; the gradient heating helps to remove moisture more evenly, avoiding the surface rupture of the composite powder caused by too fast evaporation of local moisture, and at the same time improving the drying uniformity of the surface and internal of the composite powder, thereby optimizing the drying effect of the composite powder.

[0083] In some embodiments, in step X13, the vacuum degree of the vacuum environment is -0.1 MPa, and during the drying process, every 30 min to 40 min, the vacuum degree of the vacuum environment is pumped to -0.1 MPa again. During the drying process, since water and the liquid medium for wet ball milling will volatilize, the vacuum degree of the vacuum environment will decrease, affecting the drying speed and drying effect. Therefore, every 30 min to 40 min, pumping the vacuum degree of the vacuum environment to -0.1 MPa again helps to improve the drying speed and drying effect during the drying process.

[0084] The embodiment of the present invention also provides a silicon carbide particle aluminum matrix composite material, including the silicon carbide particle aluminum matrix composite material prepared by using the preparation method of the silicon carbide particle aluminum matrix composite material described in any one of the above. The silicon carbide particle aluminum matrix composite material provided by the embodiment of the present invention has good interfacial bonding, high density and good thermophysical properties.

[0085] In some embodiments, the density of the silicon carbide particle aluminum matrix composite material is greater than or equal to 98.5%, the thermal conductivity is 220 W / m·K to 250 W / m·K, and the coefficient of thermal expansion is 5.8×10 -6 ·K -1~14.0×10 -6 ·K -1 。

[0086] Hereinafter, the preparation method of the silicon carbide particle aluminum matrix composite material provided by the present invention will be described in detail in conjunction with Examples 1 to 3.

[0087] Example 1

[0088] A) Homogenization of ball-milled silicon carbide particle aluminum matrix composite powder

[0089] Take 75.9 g of aluminum powder with a purity of over 99.95%, an average particle size of 25 μm, 74.1 g of silicon carbide particles, and an average particle size of 300 μm. The volume ratio of aluminum powder to silicon carbide particles is 11:9. Put the prepared raw material powder into an alumina ball milling tank, add 300 g of alumina ball milling beads, and use absolute ethanol as the ball milling medium, with the addition amount being 1 / 2 of the volume of the ball milling tank. Use an alumina ball milling tank with a capacity of 1 L. After loading the raw material powder and absolute ethanol, seal it with a sealing bolt. After sealing, close the intake valve on the upper cover of the ball milling tank, open the exhaust valve, and use a small vacuum pump to evacuate the tank to a vacuum, with a vacuum degree of -0.1 MPa. Then close the exhaust valve, connect the argon gas pipeline to the intake valve and open it, and fill the tank with high-purity argon gas until the internal and external air pressures are balanced. Next, open the exhaust valve and keep the argon gas discharging from the exhaust valve for 5 min. Repeat the above steps twice. After that, close the intake valve and exhaust valve of the ball milling tank, and install the ball milling tank on a QXQM-16 all-round planetary ball mill. Set the ball milling speed to 100 rpm, and the total running time of the equipment is 6 h. Stop rotating for 1 min every 5 min of operation, and at the same time change the rotation direction from clockwise to counterclockwise; continue to run for 5 min, then stop rotating for 1 min, and change to counterclockwise rotation. Refer to Figure 4 、 Figure 5 And Figure 6 , after ball milling by the method of Example 1, the silicon carbide particles have a crushing effect on the aluminum powder, significantly reducing the particle size of the aluminum powder.

[0090] B) After the ball milling is completed, before use, the vacuum in the glove box should be pumped to -0.1 MPa first, and then high-purity argon gas is introduced until it is balanced with the external air pressure. This process is repeated twice to ensure that the oxygen content in the glove box is maintained at a low level. Open the ball milling tank in the inert gas glove box, and separate the absolute ethanol and the ball milling beads in the mixed raw material powder through a sieve. Place the separated absolute ethanol slurry on a stainless steel tray and put it into the ultrasonic cleaner in the glove box for 4 h of ultrasonic oscillation dispersion. The dispersed slurry is placed in a small high-temperature vacuum drying oven in the glove box. The vacuum is pumped to -0.1 MPa, and the heating temperature is set at 50 °C. Restart the mechanical pump every 1 h to restore the vacuum to -0.1 MPa, and continue for 6 h. When the vacuum no longer drops, introduce high-purity argon gas into the drying oven, balance it to atmospheric pressure, turn off the heating function, take out the powder and put it into a vacuum bag, and an aluminum-based composite powder without agglomeration and with uniform particle size can be obtained.

[0091] C) First, open the intake valve of the vacuum hot pressing sintering furnace. After the pressure in the furnace is balanced with the outside, open the furnace door, take out the graphite mold and put it on a stainless steel tray. Take out the mold lining, punch and gasket, and spray boron nitride release agent on the inner wall of the lining and the surfaces of the punch and gasket in contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the lining, punch and gasket into the graphite mold. Take out a small amount of composite powder from the vacuum bag and fill it into the lining of the graphite mold, and the filling amount is 1 / 3 of the lining volume. Then put the graphite mold into the vacuum hot pressing sintering furnace, turn on the vacuum pump, and pump the vacuum in the furnace to 0 MPa. Close and fasten the furnace door. The vacuum hot pressing sintering process is as follows: First, heat it at a heating rate of 10 °C / min to 300 °C, hold for 30 minutes, then apply a pressure of 25 MPa, and then increase the pressure to 55 MPa at a rate of 1 MPa / min, while continuing to heat at a rate of 10 °C / min to 580 °C. After holding for 2 hours, end the heating and cool with the furnace. When the temperature drops to 400 °C, relieve the pressure and continue to cool with the furnace to room temperature to complete the sintering process. See Figure 7 , the surface of the composite material obtained in Example 1 is clean and tidy, without obvious holes. The silicon carbide particles are evenly dispersed in the aluminum matrix, but most of the silicon carbide particles protrude on the surface of the matrix. The density of the silicon carbide particle aluminum-based composite material is 99.08%, the thermal conductivity is 242 W / m·K, and the thermal expansion coefficient is 6.1×10 -6 K -1 ~12.6×10 -6 K -1 .

[0092] Example 2

[0093] A) Take 75.9 g of aluminum powder with a purity above 99.95% and an average particle size of 25 μm, and 74.1 g of silicon carbide particles with an average particle size of 300 μm. The volume ratio of the aluminum powder to the silicon carbide particles is 11:9. Put the prepared raw material powder into an alumina ball mill tank, add 300 g of alumina ball mill beads, and use anhydrous ethanol as the ball milling medium with an addition amount of 1 / 2 of the volume of the ball mill tank. Use an alumina ball mill tank with a capacity of 1 L. After loading the raw material powder and anhydrous ethanol, seal it with a sealing bolt. After sealing, close the intake valve on the upper cover of the ball mill tank, open the exhaust valve, and use a small vacuum pump to evacuate the tank to a vacuum with a vacuum degree of -0.1 MPa. Then close the exhaust valve, connect the argon gas pipeline to the intake valve and open it, and fill the tank with high-purity argon until the internal and external air pressures are balanced. Next, open the exhaust valve and keep the argon gas discharging from the exhaust valve for 5 min. Repeat the above steps twice. After that, close the intake valve and exhaust valve of the ball mill tank, and install the ball mill tank on a QXQM-16 all-round planetary ball mill. Set the ball milling speed to 100 rpm, and the total running time of the equipment is 6 h. Stop rotating for 1 min every 5 min of operation, and at the same time change the rotation direction from clockwise to counterclockwise; continue to run for 5 min, then stop rotating for 1 min, and change to counterclockwise rotation.

[0094] B) After the ball milling is completed, before use, first evacuate the glove box to a vacuum degree of -0.1 MPa, and then introduce high-purity argon until it is level with the external air pressure. Repeat this process twice to ensure that the oxygen content in the glove box is maintained at a low level. Open the ball mill tank in the inert gas glove box, and separate the anhydrous ethanol and the ball mill beads from the mixed raw material powder through a sieve. Place the separated anhydrous ethanol slurry in a stainless steel tray and put it into an ultrasonic cleaner in the glove box for 4 h of ultrasonic oscillation dispersion. Put the dispersed slurry into a small high-temperature vacuum drying oven in the glove box, evacuate the vacuum degree to -0.1 MPa, and set the heating temperature to 50 °C. Restart the mechanical pump every 1 h to restore the vacuum degree to -0.1 MPa, and continue for 6 h. When the vacuum degree no longer drops, introduce high-purity argon into the drying oven to balance to atmospheric pressure, turn off the heating function, take out the powder and put it into a vacuum bag to obtain aluminum-based composite powder without agglomeration and with uniform particle size.

[0095] C) First, open the intake valve of the vacuum hot-pressing sintering furnace. After the pressure inside the furnace is balanced with the outside, open the furnace door, take out the graphite mold and place it in a stainless steel tray. Take out the mold liner, punch, and gasket, and spray boron nitride release agent on the inner wall of the liner and the surfaces of the punch and gasket that come into contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the liner, punch, and gasket into the graphite mold. Take out a small amount of composite powder from the vacuum bag and fill it into the mold liner of the graphite mold. The filling amount is 1 / 3 of the liner volume. Then place the graphite mold into the vacuum hot-pressing sintering furnace, turn on the vacuum pump, and evacuate the vacuum degree in the furnace to 0 MPa. Close and fasten the furnace door. The vacuum hot-pressing sintering process is as follows: First, heat it at a heating rate of 10 °C / min to 300 °C, hold for 30 minutes, then apply a pressure of 25 MPa, and then increase the pressure to 50 MPa at a rate of 1 MPa / min while continuing to heat at a rate of 10 °C / min to 580 °C. After holding for 2 hours, stop heating and cool with the furnace. When the temperature drops to 400 °C, relieve the pressure and continue to cool with the furnace to room temperature to complete the sintering process. See Figure 8 , there are a small number of pores on the surface of the composite material obtained in Example 2 and at the interface between the irregular silicon carbide particles and the aluminum matrix. The density of the silicon carbide particle-reinforced aluminum matrix composite is 98.86%, the thermal conductivity is 227 W / m·K, and the thermal expansion coefficient is 6.4×10 -6 K -1 ~13.9×10 -6 K -1 .

[0096] Example 3

[0097] A) Take 75.9 g of aluminum powder with a purity above 99.95% and an average particle size of 25 μm, and 74.1 g of silicon carbide particles with an average particle size of 300 μm. The volume ratio of the aluminum powder to the silicon carbide particles is 11:9. Put the prepared raw material powder into an alumina ball milling tank, add 300 g of alumina ball milling beads, and use anhydrous ethanol as the ball milling medium with an addition amount of 1 / 2 of the volume of the ball milling tank. Use an alumina ball milling tank with a capacity of 1 L. After loading the raw material powder and anhydrous ethanol, seal it with a sealing bolt. After sealing, close the intake valve on the upper cover of the ball milling tank, open the exhaust valve, and use a small vacuum pump to evacuate the tank to a vacuum with a vacuum degree of -0.1 MPa. Then close the exhaust valve, connect the argon gas pipeline to the intake valve and open it, and fill the tank with high-purity argon until the internal and external air pressures are balanced. Next, open the exhaust valve and keep the argon gas discharging from the exhaust valve for 5 min. Repeat the above steps twice. After that, close the intake valve and exhaust valve of the ball milling tank, and install the ball milling tank on a QXQM-16 all-round planetary ball mill. Set the ball milling speed to 100 rpm and the total running time of the equipment to 6 h. Stop rotating for 1 min every 5 min of operation, and at the same time change the rotation direction from clockwise to counterclockwise; continue to run for 5 min, then stop rotating for 1 min, and change to counterclockwise rotation.

[0098] B) After the ball milling is completed, before use, first evacuate the glove box to a vacuum degree of -0.1 MPa, and then introduce high-purity argon until it is level with the external air pressure. Repeat this process twice to ensure that the oxygen content in the glove box is maintained at a low level. Open the ball milling tank in the inert gas glove box, and separate the anhydrous ethanol and the ball milling beads from the mixed raw material powder through a sieve. Place the separated anhydrous ethanol slurry in a stainless steel tray and put it into an ultrasonic cleaner in the glove box for 4 h of ultrasonic oscillation dispersion. Put the dispersed slurry into a small high-temperature vacuum drying oven in the glove box, evacuate the vacuum degree to -0.1 MPa, and set the heating temperature to 50 °C. Restart the mechanical pump every 1 h to restore the vacuum degree to -0.1 MPa for 6 h. When the vacuum degree no longer drops, introduce high-purity argon into the drying oven to balance to atmospheric pressure, turn off the heating function, take out the powder and put it into a vacuum bag to obtain an aluminum-based composite powder without agglomeration and with uniform particle size.

[0099] C) First, open the intake valve of the vacuum hot pressing sintering furnace. After the pressure inside the furnace is balanced with the outside, open the furnace door, take out the graphite mold and place it in a stainless-steel tray. Take out the mold liner, punch, and gasket, and spray boron nitride release agent on the inner wall of the liner and the surfaces of the punch and gasket that come into contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the liner, punch, and gasket into the graphite mold. Take out a small amount of composite powder from the vacuum bag and fill it into the liner of the graphite mold, with the filling amount being 1 / 3 of the liner volume. Then place the graphite mold into the vacuum hot pressing sintering furnace, turn on the vacuum pump, and evacuate the vacuum inside the furnace to 0 MPa. Close and fasten the furnace door. The vacuum hot pressing sintering process is as follows: First, heat it at a heating rate of 10 °C / min to 300 °C, hold for 30 minutes, then apply a pressure of 25 MPa, and then increase the pressure to 55 MPa at a rate of 1.5 MPa / min while continuing to heat at a rate of 10 °C / min to 580 °C. After holding for 2 hours, stop heating and cool with the furnace. When the temperature drops to 400 °C, relieve the pressure and continue to cool with the furnace to room temperature to complete the sintering process. See Figure 9 , the surface of the composite material obtained in Example 3 is flat and clean, without obvious holes. The silicon carbide particles are evenly distributed in the aluminum matrix. The density of the silicon carbide particle-reinforced aluminum matrix composite material is 99.24%, the thermal conductivity is 246 W / m·K, and the thermal expansion coefficient is 5.8×10 -6 K -1 ~11.7×10 -6 K -1 .

[0100] Example 4

[0101] A) Take 75.9 g of aluminum powder with a purity above 99.95% and an average particle size of 25 μm, and 74.1 g of silicon carbide particles with an average particle size of 300 μm. The volume ratio of the aluminum powder to the silicon carbide particles is 11:9. Put the prepared raw material powder into an alumina ball milling tank, add 300 g of alumina ball milling beads, and use absolute ethanol as the ball milling medium with an addition amount of 1 / 2 of the volume of the ball milling tank. Use an alumina ball milling tank with a capacity of 1 L. After loading the raw material powder and absolute ethanol, seal it with a sealing bolt. After sealing, close the intake valve on the upper cover of the ball milling tank, open the exhaust valve, and use a small vacuum pump to evacuate the tank to a vacuum with a vacuum degree of -0.1 MPa. Then close the exhaust valve, connect the argon gas pipeline to the intake valve and open it, and fill the tank with high-purity argon until the internal and external air pressures are balanced. Next, open the exhaust valve and keep the argon gas discharging from the exhaust valve for 5 min. Repeat the above steps twice. After that, close the intake valve and exhaust valve of the ball milling tank, and install the ball milling tank on a QXQM-16 all-round planetary ball mill. Set the ball milling speed to 100 rpm and the total running time of the equipment to 6 h. Stop the rotation for 1 min every 5 min of operation, and at the same time change the rotation direction from clockwise to counterclockwise; continue to run for 5 min, then stop for 1 min, and change to counterclockwise rotation.

[0102] B) After the ball milling is completed, before use, first evacuate the glove box to a vacuum degree of -0.1 MPa, and then introduce high-purity argon until it is equal to the external air pressure. Repeat this process twice to ensure that the oxygen content in the glove box is maintained at a low level. Open the ball milling tank in the inert gas glove box, and separate the absolute ethanol and the ball milling beads from the mixed raw material powder through a sieve. Place the separated absolute ethanol slurry in a stainless steel tray and put it into an ultrasonic cleaner in the glove box for 4 h of ultrasonic oscillation dispersion. Put the dispersed slurry into a small high-temperature vacuum drying oven in the glove box, evacuate the vacuum degree to -0.1 MPa, and set the heating temperature to 50 °C. Restart the mechanical pump every 1 h to restore the vacuum degree to -0.1 MPa for 6 h. When the vacuum degree no longer drops, introduce high-purity argon into the drying oven, balance it to atmospheric pressure, turn off the heating function, take out the powder and put it into a vacuum bag to obtain an aluminum-based composite powder without agglomeration and with uniform particle size.

[0103] C) First, open the intake valve of the vacuum hot-pressing sintering furnace. After the pressure inside the furnace is balanced with the outside, open the furnace door, take out the graphite mold and place it in a stainless-steel tray. Take out the mold liner, punch, and gasket, and spray boron nitride release agent on the inner wall of the liner and the surfaces of the punch and gasket that come into contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the liner, punch, and gasket into the graphite mold. Take out a small amount of composite powder from the vacuum bag and fill it into the liner of the graphite mold, with the filling amount being 1 / 3 of the liner volume. Then place the graphite mold into the vacuum hot-pressing sintering furnace, turn on the vacuum pump, and evacuate the vacuum degree inside the furnace to 0 MPa. Close and fasten the furnace door. The vacuum hot-pressing sintering process is as follows: First, heat it at a heating rate of 10 °C / min to 300 °C, hold for 30 minutes, then apply a pressure of 25 MPa, and then increase the pressure to 55 MPa at a rate of 1.5 MPa / min while continuing to heat at a rate of 10 °C / min to 580 °C. After holding for 3 hours, stop heating and cool with the furnace. When the temperature drops to 400 °C, relieve the pressure and continue to cool with the furnace to room temperature to complete the sintering process. Refer to Figure 10 , the surface of the composite material obtained in Example 4 is relatively clean and tidy as a whole, without obvious holes. The interfacial bonding between the silicon carbide particles and the aluminum matrix is good, and the particles are evenly distributed in the aluminum matrix. The density of the silicon carbide particle aluminum matrix composite material is 99.01%, the thermal conductivity is 237 W / m·K, and the thermal expansion coefficient is 6.3×10 -6 K -1 ~12.5×10 -6 K -1 .

[0104] Example 5

[0105] A) Take 75.9 g of aluminum powder with a purity above 99.95% and an average particle size of 25 μm, and 74.1 g of silicon carbide particles with an average particle size of 300 μm. The volume ratio of the aluminum powder to the silicon carbide particles is 11:9. Put the prepared raw material powder into an alumina ball milling tank, add 300 g of alumina ball milling beads, and use absolute ethanol as the ball milling medium with an addition amount of 1 / 2 of the volume of the ball milling tank. Use an alumina ball milling tank with a capacity of 1 L. After loading the raw material powder and absolute ethanol, seal it with a sealing bolt. After sealing, close the intake valve on the upper cover of the ball milling tank, open the exhaust valve, and use a small vacuum pump to evacuate the tank to a vacuum with a vacuum degree of -0.1 MPa. Then close the exhaust valve, connect the argon gas pipeline to the intake valve and open it, and fill the tank with high-purity argon until the internal and external air pressures are balanced. Next, open the exhaust valve and keep the argon gas discharging from the exhaust valve for 5 min. Repeat the above steps twice. After that, close the intake valve and exhaust valve of the ball milling tank, and install the ball milling tank on a QXQM-16 all-round planetary ball mill. Set the ball milling speed to 100 rpm, and the total running time of the equipment is 6 h. Stop rotating for 1 min every 5 min of operation, and at the same time change the rotation direction from clockwise to counterclockwise; continue to run for 5 min, then stop rotating for 1 min, and change to counterclockwise rotation.

[0106] B) After the ball milling is completed, before use, first evacuate the glove box to a vacuum degree of -0.1 MPa, and then introduce high-purity argon until it is level with the external air pressure. Repeat this process twice to ensure that the oxygen content in the glove box is maintained at a low level. Open the ball milling tank in the inert gas glove box, and separate the absolute ethanol and the ball milling beads from the mixed raw material powder through a sieve. Place the separated absolute ethanol slurry in a stainless steel tray and put it into an ultrasonic cleaner in the glove box for 4 h of ultrasonic oscillation dispersion. Put the dispersed slurry into a small high-temperature vacuum drying oven in the glove box, evacuate the vacuum degree to -0.1 MPa, and set the heating temperature to 50 °C. Restart the mechanical pump every 1 h to restore the vacuum degree to -0.1 MPa for 6 h. When the vacuum degree no longer drops, introduce high-purity argon into the drying oven to balance to atmospheric pressure, turn off the heating function, take out the powder and put it into a vacuum bag to obtain aluminum-based composite powder without agglomeration and with uniform particle size.

[0107] C) First, open the intake valve of the vacuum hot-pressing sintering furnace. After the pressure inside the furnace is balanced with the outside, open the furnace door, take out the graphite mold and place it in a stainless-steel tray. Remove the mold liner, punch, and gasket, and spray boron nitride release agent on the inner wall of the liner and the surfaces of the punch and gasket that come into contact with the composite powder. After the alcohol in the release agent has completely evaporated, reassemble the liner, punch, and gasket into the graphite mold. Take out a small amount of composite powder from the vacuum bag and fill it into the liner of the graphite mold, with the filling amount being 1 / 3 of the liner volume. Then place the graphite mold into the vacuum hot-pressing sintering furnace, turn on the vacuum pump, and evacuate the vacuum inside the furnace to 0 MPa. Close and fasten the furnace door. The vacuum hot-pressing sintering process is as follows: First, heat it at a heating rate of 10 °C / min to 300 °C, hold for 30 minutes, then apply a pressure of 25 MPa, and then increase the pressure to 55 MPa at a rate of 1.5 MPa / min while continuing to heat at a rate of 10 °C / min to 570 °C. After holding for 2 hours, end the heating and cool it in the furnace. When the temperature drops to 400 °C, relieve the pressure and continue to cool in the furnace to room temperature to complete the sintering process. Refer to Figure 11 , the composite material obtained by Example 5 shows obvious rough features and has a relatively large number of large-size hole defects. At the same time, there are pores at the interface between the silicon carbide particles and the aluminum matrix. Although the silicon carbide particles are evenly distributed in the aluminum matrix, the performance has decreased. The density of the silicon carbide particle aluminum matrix composite material is 98.80%, the thermal conductivity is 220 W / m·K, and the thermal expansion coefficient is 6.8×10 -6 K -1 ~13.9×10 -6 K -1 .

[0108] The above-described embodiments of the present invention do not constitute a limitation on the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a silicon carbide particle aluminum matrix composite, characterized in that, Including the steps: (X1) Wet ball-mill, disperse, and dry aluminum powder and silicon carbide particles with preset volume fractions respectively to obtain silicon carbide particle aluminum matrix composite powder. The wet ball-milling specifically includes alternately rotating the ball-mill clockwise and counterclockwise, and pausing during the alternation; (X2) Vacuum sinter the silicon carbide particle aluminum matrix composite powder obtained in step (X1), and perform gradient heating during the vacuum sintering to obtain silicon carbide particle aluminum matrix composite material.

2. The preparation method according to claim 1, characterized in that, (X2) The step specifically includes: (X21) First-stage heating: Raise the temperature to 300°C - 400°C at a heating rate of 6°C / min - 10°C / min; (X22) First-stage insulation: 10 min - 30 min; (X23) Second-stage heating: Continue to raise the temperature to 500°C - 600°C at a rate of 8°C / min - 10°C / min; (X24) Second-stage insulation: Insulate for 1 h - 3 h; (X25) End heating and perform cooling.

3. The preparation method according to claim 2, wherein (X2) The step further includes: In step (X23), apply a pressure of 20 MPa - 25 MPa to the silicon carbide particle aluminum matrix composite powder, and during the heating process, increase the pressure applied to the silicon carbide particle aluminum matrix composite powder from 1 MPa / min - 1.5 MPa / min to 50 MPa - 55 MPa; In step (X25), when cooling to a temperature of 400°C, stop applying pressure to the silicon carbide particle aluminum matrix composite powder, and then continue to cool.

4. The preparation method according to claim 1, characterized in that, (X1) The step specifically includes: (X11) Wet ball-mill aluminum powder and silicon carbide particles with preset volume fraction ratios under a protective atmosphere to obtain composite powder. The wet ball-milling specifically includes alternately rotating the ball-mill clockwise and counterclockwise, and pausing during the alternation; (X12) Place the composite powder obtained in step (X11) in a protective atmosphere for ultrasonic dispersion to obtain dispersed composite powder; (X13) Place the dispersed composite powder obtained in step (X12) in a vacuum environment for drying treatment to obtain the silicon carbide particle aluminum matrix composite powder.

5. The preparation method according to claim 4, characterized in that, (X11) The duration of each clockwise rotation ball-milling and each counterclockwise rotation ball-milling is 3 min - 5 min respectively; the pause time during alternation is 1 min - 2 min, and the total time of the wet ball-milling is 6 h.

6. The preparation method according to claim 4, characterized in that, (X11) The average particle size of the aluminum powder is 25 μm - 30 μm; the average particle size of the silicon carbide particles is 250 μm - 300 μm.

7. The preparation method according to claim 4, wherein (X11) The preset volume fraction ratio of the aluminum powder to the silicon carbide particles is 10 - 11:10 - 9.

8. The preparation method according to claim 4, characterized in that, (X13) In the drying treatment, the initial temperature is 30°C - 40°C, and the temperature is raised by 5°C - 8°C every 2 h - 4 h until the temperature reaches 50°C - 60°C, and then dried for 24 h - 48 h.

9. A silicon carbide particle aluminum matrix composite, characterized in that, The aluminum matrix composite material with silicon carbide particles prepared by the preparation method of the aluminum matrix composite material with silicon carbide particles according to any one of claims 1 to 8 is included.

10. The silicon carbide particulate aluminum matrix composite according to claim 9, characterized in that, The density of the silicon carbide particle aluminum matrix composite is greater than or equal to 98.5%, the thermal conductivity is 220 W / m·K to 250 W / m·K, and the coefficient of thermal expansion is 5.8×10 -6 ·K -1 ~14.0×10 -6 ·K -1 .

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