Ceramic-reinforced aluminum-based composite material and preparation method therefor

Abstract

The present invention belongs to the technical field of aluminum-based composite materials. Disclosed are a ceramic-reinforced aluminum-based composite material and a preparation method therefor. The preparation method comprises: S1, adding silicon carbide grinding balls and a second solvent to aluminum powder (1-10 µm), graded silicon carbide particles, chromite and iron pyrite, and performing first-stage ball milling and material mixing, wherein the silicon carbide particles consist of first silicon carbide particles (10-12 µm) and second silicon carbide particles (25-30 µm) at a volume ratio of (3-4):(6-7) and account for 55-60% of the total volume of the silicon carbide particles and the aluminum powder; S2, adding polyvinylpyrrolidone, and performing second-stage ball milling and material mixing; S3, drying same after the material mixing; and S4, performing hot-pressed sintering, wherein the sintering temperature is 560-580 °C, the pressure is 20-40 MPa, and the holding time is 10-15 min. In the present invention, by designing the particle sizes and ratio of the raw materials, optimizing process steps, etc., a ceramic-reinforced aluminum-based composite material which has good compactness, high strength, a high heat conductivity and a small expansion coefficient is eventually obtained.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of aluminum-based composite materials, and specifically relates to a ceramic-reinforced aluminum-based composite material and a preparation method therefor.BACKGROUND

[0002] As a type of lightweight and high-strength multifunctional composite materials, ceramic particle-reinforced aluminum-based composite materials have excellent physical and chemical properties such as low density, high specific strength, high specific stiffness, high wear resistance, a low coefficient of thermal expansion, high thermal conductivity, and good corrosion resistance. They are promising structural materials and have been rapidly developed in recent years. Composite materials prepared with different formulation compositions and contents, different preparation processes, and heat treatment processes have different properties, enabling them to meet the application requirements in the fields of space engineering materials and electronic packaging.

[0003] In the preparation processes of ceramic particle-reinforced metal-based composite materials, the most important part is the way to add reinforcing particles into a matrix metal uniformly or achieving a desired distribution pattern, while controlling parameters such as a volume fraction of the particles as needed, in order to prepare a required target material. Currently, the commonly used methods for preparing particle-reinforced aluminum-based composite materials include stir casting, liquid metal infiltration, spray deposition, powder metallurgy, etc.

[0004] The stir casting method achieves the purpose of adding reinforcing particles by adding them to a liquid or molten metal and stirring. This method makes it difficult to achieve uniform particle distribution, which affects the properties of the prepared material. The infiltration casting method first shapes reinforcing particles as required to form a reinforcing particle framework, and then allows a molten metal matrix to infiltrate into gaps of the reinforcing particle framework under vacuum, pressure, or a combination thereof, filling them to achieve mixing. This method is prone to defects such as porosity, which affect material properties. In the spray deposition method, the metal matrix is in an atomized state during mixing. First, the matrix metal is heated to a liquid state, then further atomized and mixed with reinforcing particles, and finally, the composite material is obtained through deposition. The prepared material is not fully dense and requires subsequent treatment such as extrusion to improve properties, while processes such as atomization involve high costs. In the powder metallurgy hot pressing sintering method, reinforcing particles and a matrix metal are mixed in a powder state, followed by hot pressing and compaction. Its advantages lie in arbitrary adjustment of the volume fraction of the reinforcing phase and accurate control of the composition ratio. Mixing in the powder state allows more uniform distribution of the reinforcing particles, leading to better material properties compared to other preparation processes.

[0005] In the prior art, many ceramic particle-reinforced aluminum-based composite materials involve excessive additives, complex preparation processes, and high production costs. For example, the invention application CN113957281A entitled "High Pressure Preparation Process for Massive Medium-to-High Volume Fraction Aluminum-Based Composite Material" discloses "mixing a ceramic powder and an aluminum matrix powder; placing the mixed powder into a metal jacket for cold pressing, then seal-welding the jacket and welding an extraction pipe; putting the metal jacket into a steel mold, placing the steel mold in a resistance furnace for heating, then using a vacuum pumping device to evacuate the extraction pipe, and finally seal-welding the extraction pipe; after heating and holding the steel mold, transferring the steel mold to a press, tightening the steel mold around its circumference, then applying bidirectional pressure for consolidation; after the mold cools, removing a billet and stripping off the jacket to obtain a massive medium-to-high volume fraction aluminum-based composite material. This production process is highly complex and has a long production cycle, making it unsuitable for large-scale industrial production.

[0006] Therefore, there is a need to develop a ceramic particle-reinforced aluminum-based composite material suitable for large-scale industrial production and a preparation method therefor, so as to obtain a composite material with balanced properties such as moderate strength, good thermal conductivity, a low coefficient of thermal expansion, high temperature resistance, and wear resistance, for use in technical fields that demand high strength and heat transfer performance and low thermal deformation.SUMMARY

[0007] The problem to be solved by the present disclosure is to provide a ceramic-reinforced aluminum-based composite material and a preparation method therefor. By designing particle sizes and ratios of raw materials, optimizing process steps, etc., a ceramic-reinforced aluminum-based composite material which is suitable for industrial production and has good densification, high strength, high heat conductivity and a low coefficient of thermal expansion is eventually obtained.

[0008] The present disclosure provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S1, adding silicon carbide grinding balls and a second solvent to an aluminum powder, silicon carbide particles, a chromite, and a pyrite, and performing first-stage ball milling mixing, where the silicon carbide particles consist of first silicon carbide particles and second silicon carbide particles in a volume ratio of (3-4):(6-7), the first silicon carbide particles have a particle size of 10-12 µm, the second silicon carbide particles have a particle size of 25-30 µm, a volume of the silicon carbide particles accounts for 55%-60% of a total volume of the silicon carbide particles and the aluminum powder, and the aluminum powder has a particle size of 1-10 µm; S2, adding polyvinylpyrrolidone to a mixture from the ball milling in S1, and performing second-stage ball milling mixing; S3, mixing and then drying the mixture obtained from S2; and S4, performing hot pressing sintering on the mixture obtained from S3 at a temperature of 560-580 °C, a pressure of 20-40 MPa, and a heat preservation time of 10-15 min.

[0009] Furthermore, the method further includes: S0, ultrasonically cleaning the silicon carbide particles in a first solvent, and then drying the cleaned particles, where the first solvent comprises alcohol or deionized water; the ultrasonic cleaning is carried out once or twice, with each cleaning lasting 1-30 min; and the drying after cleaning is carried out at a temperature of 80-120 °C for 4-6 h.

[0010] Furthermore, in S1, a mass of the chromite is 0.5%-1% of a total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

[0011] Furthermore, in S1, a mass of the pyrite is 1%-2% of the total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

[0012] Furthermore, in S1, the second solvent includes alcohol, a mass ratio of the raw materials to the second solvent is 2:1, and a mass ratio of the raw materials to the silicon carbide grinding balls is 1:2.

[0013] Furthermore, in S1, the silicon carbide grinding balls include first particle size grinding balls and second particle size grinding balls in a mass ratio of 1:1, the first particle size grinding balls have a particle size of 2-3 mm, and the second particle size grinding balls have a particle size of 8-9 mm.

[0014] Furthermore, in S2, a mass of the polyvinylpyrrolidone is 0.3%-1% of the total mass of the silicon carbide particles and the aluminum powder.

[0015] Furthermore, in S1, the first-stage ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h; in S2, the second-stage ball milling is carried out at a rotational speed of 300-350 r / min for 1-1.5 h.

[0016] Furthermore, in S3, the drying after mixing is carried out at a temperature of 70-120 °C for 8-10 h.

[0017] The present disclosure further provides a ceramic-reinforced aluminum-based composite material obtained by the preparation method of a ceramic-reinforced aluminum-based composite material in any of the above.

[0018] Beneficial effects of the present disclosure are as follows: 1. By adding 55%-60% of silicon carbide (SiC) particles, the resulting ceramic-reinforced aluminum-based composite material exhibits a high ceramic volume fraction. Metallic aluminum has good thermal conductivity but a high coefficient of thermal expansion. In the present disclosure, the silicon carbide particles are added to the aluminum matrix, and the ceramic volume fraction is controlled to 55%-60%, ensuring that the resulting ceramic-reinforced aluminum-based composite material has a high ceramic volume fraction, good thermal conductivity, and a low coefficient of thermal expansion. 2. By adding the silicon carbide particles of two different sizes, the coefficient of thermal expansion of the composite material is reduced and the thermal conductivity is improved. The aluminum powder (with a particle size of 5-10 µm) is smaller than the silicon carbide particles, allowing the aluminum particles to surround the silicon carbide particles and fill gaps between the two types of silicon carbide particles. This not only enhances thermal conductivity but also ensures, during sintering, that the molten aluminum better bonds the silicon carbide particles of the two sizes together. The combination of particle sizes and their ratio ensures balanced properties of the composite material, and can more effectively reinforce the aluminum matrix. The smaller silicon carbide particles fill the voids among the larger ones, effectively improving density. The denser the composite material, the lower its coefficient of thermal expansion. 3. The added polyvinylpyrrolidone acts as a dispersant for wet mixing, promoting uniform mixing of the aluminum powder and the silicon carbide particles during ball milling. The raw materials of the present disclosure contain chromite and pyrite. The chromite is represented by an iron-chromium oxide with the molecular formula FeCr 2 O 4 . By adding the chromite, the wear resistance and strength of the composite material can be improved, and the thermal conductivity of the composite material can be further effectively improved. The main component of the pyrite is ferrous disulfide, with the molecular formula of FeS 2 . The sulfide (e.g., FeS 2 ) can increase the surface activity of both aluminum and ceramic particles during hot pressing sintering, thereby promoting bonding between solid particles, significantly shortening sintering time, and reducing energy consumption. 4. Through the hot pressing sintering, the volume fraction of the reinforcing phase can be arbitrarily adjusted, the composition ratio of the reinforcing phase can be relatively accurately controlled, and the particle size of the reinforcing phase can be adjusted from the nanometer to the micrometer range. In addition, compared to pressureless sintering, the hot pressing sintering requires a lower sintering temperature and a shorter sintering time, resulting in fewer pores and gaps in the composite material and stronger bonding between the reinforcing particles and the matrix. 5. By using the powder metallurgy process, the overall process is simple, and the composite material has fewer pores and gaps, and stronger bonding between the reinforcing particles and the matrix. By designing the particle sizes and ratios of the raw materials and optimizing process steps and parameters, the coefficient of thermal expansion is reduced, the raw materials are mixed more uniformly, the interfacial bonding between the reinforcing phase and the matrix is improved, and the ultimately obtained ceramic-reinforced aluminum-based composite material exhibits good densification, high strength, high thermal conductivity, and a low coefficient of thermal expansion. The ceramic-reinforced aluminum-based composite material prepared in the present disclosure has the advantages of high strength (380-390 MPa), high thermal conductivity (230-240 W / (m.k)), and a low coefficient of thermal expansion ((12-14) × 10 -6< K), and can be applied in electronic packaging materials or as heat transfer plates for electronic components. BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a process flowchart for preparing a ceramic-reinforced aluminum-based composite material in one embodiment of the present disclosure; FIG. 2 shows a physical sample of a ceramic-reinforced aluminum-based composite material in Embodiment 1 of the present disclosure; FIG. 3 shows a physical sample of a ceramic-reinforced aluminum-based composite material in Embodiment 5 of the present disclosure; FIG. 4 shows a physical sample of a ceramic-reinforced aluminum-based composite material in Comparative Embodiment 6 of the present disclosure; FIG. 5 shows an electron microscope image of a ceramic-reinforced aluminum-based composite material sample in Embodiment 5 of the present disclosure; and FIG. 6 shows an electron microscope image of a ceramic-reinforced aluminum matrix composite material sample in Comparative Embodiment 9 of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the objectives, technical solutions, and advantages of the present disclosure clearer, the present disclosure will be further described in detail in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present disclosure and are not intended to limit the present disclosure.

[0021] As shown in FIG. 1, an embodiment of the present disclosure provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S1. Add silicon carbide grinding balls and a second solvent to an aluminum powder, silicon carbide particles, a chromite, and a pyrite, and perform first-stage ball milling mixing.

[0022] The silicon carbide particles consist of first silicon carbide particles and second silicon carbide particles in a volume ratio of (3-4):(6-7), the first silicon carbide particles have a particle size of 10-12 µm, and the second silicon carbide particles have a particle size of 25-30 µm. By adding the silicon carbide particles of two different sizes, the coefficient of thermal expansion is reduced and the thermal conductivity is improved. The aluminum powder (with a particle size of 5-10 µm) is smaller than the silicon carbide particles, allowing the aluminum particles to surround the silicon carbide particles and fill gaps between the two types of silicon carbide particles. This not only enhances thermal conductivity but also ensures, during sintering, that the molten aluminum better bonds the silicon carbide particles of the two sizes together. The combination of particle sizes and their ratio ensures balanced properties of the composite material, and can more effectively reinforce the aluminum matrix. The smaller silicon carbide particles fill the voids among the larger ones, effectively improving density. The denser the composite material, the lower its coefficient of thermal expansion.

[0023] The volume of the silicon carbide particles accounts for 55%-60% of the total volume of the silicon carbide particles and the aluminum powder (calculated from the mass ratio of the silicon carbide particles to the aluminum powder and the respective densities), and the aluminum powder has a particle size of 1-10 µm. By adding 55%-60% of silicon carbide particles, the resulting ceramic-reinforced aluminum-based composite material exhibits a high ceramic volume fraction. Mixing in a powder state leads to a more uniform distribution of the silicon carbide reinforcing particles, and better material properties compared to other preparation processes. The chromite is represented by an iron-chromium oxide with the molecular formula FeCr 2 O 4 , which may contain some magnesium and aluminum, thereby enhancing wear resistance, strength, and thermal conductivity. The pyrite is primarily ferrous disulfide with the molecular formula FeS 2 , which can shorten the sintering and molding time and reduce energy consumption.

[0024] S2. Add polyvinylpyrrolidone (grade K30) to a mixture from the ball milling in S1, and perform second-stage ball milling mixing; The two-stage ball milling process enhances the uniformity of reinforcing particle distribution and the interfacial bonding between the reinforcing particles and the aluminum matrix, thereby improving the service performance of the composite material. In the second-stage ball milling mixing, the polyvinylpyrrolidone acts as a dispersant for wet mixing, promoting uniform mixing of the aluminum powder and the silicon carbide particles during ball milling. The polyvinylpyrrolidone completely decomposes during hot pressing sintering and has no adverse impact on the properties of the composite material.

[0025] S3. Mix and then dry the mixture obtained from S2.

[0026] S4. Perform hot pressing sintering on the mixture obtained from S3 at a temperature of 560-580 °C, a pressure of 20-40 MPa, and a heat preservation time of 10-15 min.

[0027] Through the hot pressing sintering, the volume fraction of the reinforcing phase can be arbitrarily adjusted, the composition ratio of the reinforcing phase can be relatively accurately controlled, and the particle size of the reinforcing phase can be adjusted from the nanometer to the micrometer range. In addition, compared to pressureless sintering, the hot pressing sintering requires a lower sintering temperature and a shorter duration, resulting in fewer pores and gaps in the composite material and stronger bonding between the reinforcing particles and the matrix.

[0028] By using the powder metallurgy process in the embodiments of the present disclosure, the overall process is simple, and the composite material has fewer pores and gaps, and stronger bonding between the reinforcing particles and the matrix. By designing the particle sizes and ratios of the raw materials, adding the ball milling pretreatment of the silicon carbide particles, and optimizing the wet ball milling mixing process, the coefficient of thermal expansion is reduced, the raw materials are mixed more uniformly, the interfacial bonding between the reinforcing phase and the matrix is improved, and the ultimately obtained ceramic-reinforced aluminum-based composite material exhibits high density, high strength, high thermal conductivity, and a low coefficient of thermal expansion.

[0029] In a preferred embodiment, the method further includes: S0. Ultrasonically clean the silicon carbide particles in a first solvent, and then dry the cleaned particles, where the first solvent comprises alcohol or deionized water; the ultrasonic cleaning is carried out once or twice, with each cleaning lasting 1-30 min; and the drying after cleaning is carried out at a temperature of 80-120 °C for 4-6 h.

[0030] The present disclosure has found through preliminary tests that fine adsorbates on the surface of silicon carbide particles readily adsorb gas molecules. When a certain amount of adsorbates are present on the surface of silicon carbide particles, the small-sized adsorbed particles exhibit a strong gas adsorption capacity. The presence of localized gas adsorption reduces the wettability between the particles and the molten aluminum at that location, leading to gas entrapment during the infiltration process. This consequently reduces the wettability between the ceramic particles and the molten aluminum, resulting in non-uniform dispersion of ceramic particles in the molten aluminum. In the present disclosure, the silicon carbide particles are ultrasonically cleaned prior to ball milling. Since the adsorbates are physically adsorbed onto the silicon carbide particles, with the bonding force being a weak intermolecular force, fine particles can be effectively removed through cavitation and acoustic streaming impact during the ultrasonication, thereby achieving a purpose of surface cleaning. Experimental comparison shows that under the same formulation and hot pressing process conditions, the relative density of samples prepared from cleaned silicon carbide particles is approximately 1% higher than that of samples prepared from uncleaned silicon carbide particles.

[0031] In S1, a mass of the chromite is 0.5%-1% of a total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

[0032] In S1, a mass of the pyrite is 1%-2% of the total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

[0033] In S1, the second solvent comprises alcohol, a mass ratio of the raw materials to the second solvent is 2:1, and a mass ratio of the raw materials to the silicon carbide grinding balls is 1:2.

[0034] In S1, the silicon carbide grinding balls include first particle size grinding balls and second particle size grinding balls in a mass ratio of 1:1, the first particle size grinding balls have a particle size of 2-3 mm, and the second particle size grinding balls have a particle size of 8-9 mm. The uniformity of reinforcing particle distribution and the interfacial bonding between the reinforcing particles and the aluminum matrix are two key factors affecting the service performance of the composite material. In preliminary ball milling tests, the present disclosure has found that using grinding balls of a single size for ball milling results in a wider particle size distribution of SiC particles under the same time and rotational speed. Compared to using a single type of ball milling medium, using the grinding balls of two different sizes for ball milling achieves higher ball milling efficiency and allows for more uniform mixing of various raw material particles. When the grinding balls of two different sizes are used for ball milling, the large-sized ball milling medium first disperses the powder material, while the small-sized ball milling medium simultaneously subjects the micro-agglomerated powder to high-frequency extrusion and impact. The combination of the grinding media of two sizes efficiently converts gravitational potential energy to the powder being milled, improving mixing efficiency in a short time and enhancing the dispersion uniformity of the materials, thereby ensuring that the ceramic particles are uniformly dispersed into the aluminum powder. In the present disclosure, the silicon carbide grinding balls of two sizes (particle sizes) are used for high-energy ball milling mixing, which can effectively change the morphology of the silicon carbide particles and control their particle size. During the ball milling process, the silicon carbide particles are continuously squeezed into the gaps between the aluminum matrix particles through the impact, compression, and shearing actions of the grinding balls, and are uniformly dispersed within the aluminum matrix, thereby forming and improving the interfacial bonding between the silicon carbide particles and the aluminum matrix.

[0035] In S2, a mass of the polyvinylpyrrolidone is 0.3%-1% of the total mass of the silicon carbide particles and the aluminum powder.

[0036] In S1, the first-stage ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h. In S3, the second-stage ball milling is carried out at a rotational speed of 300-350 r / min for 1-1.5 h.

[0037] In S3, the drying after mixing is carried out at a temperature of 70-120 °C for 8-10 h.

[0038] The ceramic-reinforced aluminum-based composite material obtained by the above preparation method has the advantages of high strength (380-390 MPa), high thermal conductivity (230-240 W / (m.k)), and a low coefficient of thermal expansion ((12-14) × 10 -6< K), and can be applied in electronic packaging materials or as heat transfer plates for electronic components.Embodiment 1

[0039] This Embodiment provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S1. An aluminum powder (5-10 µm), SiC particles (accounting for 55% of a total volume of aluminum powder and SiC particles, including two specifications of SiC particles of 10-12 µm and 25-30 µm in a volume ratio, i.e., mass ratio, of 3.5:6.5), a chromite (15-25 µm, with a mass being 0.5% of a total mass of aluminum powder and SiC particles), and a pyrite (15-25 µm, with a mass being 1% of the total mass of aluminum powder and SiC particles) are placed together with SiC grinding balls in a ball mill, and alcohol is added, where the SiC grinding balls consist of 2-3 mm grinding balls and 8-9 mm grinding balls in a mass ratio of 1:1, a mass ratio of the total powder to the grinding balls is 1:2, and a mass ratio of the total powder to the alcohol is 2:1. Ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h.

[0040] S2. A polyvinylpyrrolidone powder, with a mass being 0.3% of the total mass of aluminum powder and silicon carbide powder, is added. The ball milling is continued at a rotational speed of 300-350 r / min for 1-1.5 h.

[0041] S3. After ball milling mixing is completed, the mixture is dried at a temperature of 70-100 °C for 10 h.

[0042] S4. The mixed and dried powder is loaded into a mold for hot pressing sintering at a temperature of 580 °C, a pressure of 20 MPa, and a heat preservation time of 10 min.Embodiment 2

[0043] This Embodiment provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S1. An aluminum powder (5-10 µm), SiC particles (accounting for 55% of a total volume of aluminum powder and SiC particles, including two specifications of SiC particles of 10-12 µm and 25-30 µm in a volume ratio, i.e., mass ratio, of 3:7), a chromite (15-25 µm, with a mass being 1% of a total mass of aluminum powder and SiC particles), and a pyrite (15-25 µm, with a mass being 2% of the total mass of aluminum powder and SiC particles) are placed together with SiC grinding balls in a ball mill, and alcohol is added, where the SiC grinding balls consist of 2-3 mm grinding balls and 8-9 mm grinding balls in a mass ratio of 1:1, a mass ratio of the total powder to the grinding balls is 1:2, and a mass ratio of the total powder to the alcohol is 2:1. Ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h.

[0044] S2. A polyvinylpyrrolidone powder, with a mass being 1% of the total mass of aluminum powder and silicon carbide powder, is added. The ball milling is continued at a rotational speed of 300-350 r / min for 1-1.5 h.

[0045] S3. After ball milling mixing is completed, the mixture is dried at a temperature of 70-100 °C for 10 h.

[0046] S4. The mixed and dried powder is loaded into a mold for hot pressing sintering at a temperature of 560 °C, a pressure of 40 MPa, and a heat preservation time of 15 min.Embodiment 3

[0047] As shown in FIG. 1, this Embodiment provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S0. SiC particles (accounting for 55% of a total volume of aluminum powder and SiC particles, including two specifications of SiC particles of 10-12 µm and 25-30 µm in a volume ratio, i.e., mass ratio, of 3:7) are ultrasonically cleaned twice in alcohol, with each cleaning lasting 1-15 min. The cleaned SiC particles are dried at a temperature of 80-100 °C for 6 h.

[0048] S1. An aluminum powder (5-10 µm), the SiC particles cleaned in S0, a chromite (15-25 µm, with a mass being 0.8% of a total mass of aluminum powder and SiC particles), and a pyrite (15-25 µm, with a mass being 1.5% of the total mass of aluminum powder and SiC particles) are placed together with SiC grinding balls in a ball mill, and alcohol is added, where the SiC grinding balls consist of 2-3 mm grinding balls and 8-9 mm grinding balls in a mass ratio of 1:1, a mass ratio of the total powder to the grinding balls is 1:2, and a mass ratio of the total powder to the alcohol is 2:1. Ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h.

[0049] S2. A polyvinylpyrrolidone powder, with a mass being 0.8% of the total mass of aluminum powder and silicon carbide powder, is added. The ball milling is continued at a rotational speed of 300-350 r / min for 1-1.5 h.

[0050] S3. After ball milling mixing is completed, the mixture is dried at a temperature of 90-120 °C for 8 h.

[0051] S4. The mixed and dried powder is loaded into a mold for hot pressing sintering at a temperature of 560 °C, a pressure of 40 MPa, and a heat preservation time of 10 min.Embodiment 4

[0052] This Embodiment provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S0. SiC particles (accounting for 52% of a total volume of aluminum powder and SiC particles, including two specifications of SiC particles of 10-12 µm and 25-30 µm in a volume ratio, i.e., mass ratio, of 4:6) are ultrasonically cleaned twice in deionized water, with each cleaning lasting 15-30 min. The cleaned SiC particles are dried at a temperature of 100-120 °C for 4 h.

[0053] S1. An aluminum powder (5-10 µm), the SiC particles cleaned in S0, a chromite (15-25 µm, with a mass being 0.5% of a total mass of aluminum powder and SiC particles), and a pyrite (15-25 µm, with a mass being 1% of the total mass of aluminum powder and SiC particles) are placed together with SiC grinding balls in a ball mill, and alcohol is added, where the SiC grinding balls consist of 2-3 mm grinding balls and 8-9 mm grinding balls in a mass ratio of 1:1, a mass ratio of the total powder to the grinding balls is 1:2, and a mass ratio of the total powder to the alcohol is 2:1. Ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h.

[0054] S2. A polyvinylpyrrolidone powder, with a mass being 0.3% of the total mass of aluminum powder and silicon carbide powder, is added. The ball milling is continued at a rotational speed of 300-350 r / min for 1-1.5 h.

[0055] S3. After ball milling mixing is completed, the mixture is dried at a temperature of 70-100 °C for 10 h.

[0056] S4. The mixed and dried powder is loaded into a mold for hot pressing sintering at a temperature of 580 °C, a pressure of 30 MPa, and a heat preservation time of 15 min.Embodiment 5

[0057] This Embodiment provides a preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S0. SiC particles (accounting for 60% of a total volume of aluminum powder and SiC particles, including two specifications of SiC particles of 10-12 µm and 25-30 µm in a volume ratio, i.e., mass ratio, of 3.5:6.5) are ultrasonically cleaned twice in alcohol, with each cleaning lasting 1-15 min. The cleaned SiC particles are dried at a temperature of 80-100 °C for 6 h.

[0058] S1. An aluminum powder (5-10 µm), the SiC particles cleaned in S0, a chromite (15-25 µm, with a mass being 0.5% of a total mass of aluminum powder and SiC particles), and a pyrite (15-25 µm, with a mass being 1% of the total mass of aluminum powder and SiC particles) are placed together with SiC grinding balls in a ball mill, and alcohol is added, where the SiC grinding balls consist of 2-3 mm grinding balls and 8-9 mm grinding balls in a mass ratio of 1:1, a mass ratio of the total powder to the grinding balls is 1:2, and a mass ratio of the total powder to the alcohol is 2:1. Ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h.

[0059] S2. A polyvinylpyrrolidone powder, with a mass being 0.3% of the total mass of aluminum powder and silicon carbide powder, is added. The ball milling is continued at a rotational speed of 300-350 r / min for 1-1.5 h.

[0060] S3. After ball milling mixing is completed, the mixture is dried at a temperature of 70-100 °C for 10 h.

[0061] S4. The mixed and dried powder is loaded into a mold for hot pressing sintering at a temperature of 560 °C, a pressure of 20 MPa, and a heat preservation time of 15 min.

[0062] In Comparative Embodiments 1-8, the same process steps as in Embodiment 1 are employed, except that no chromite, pyrite, or polyvinylpyrrolidone is added during the preparation process. Other distinguishing process parameters are shown in Table 1.

[0063] In Comparative Embodiment 9, the same process steps as in Embodiment 5 are used, except that no polyvinylpyrrolidone is added in S2. Other distinguishing process steps are shown in Table 1.

[0064] In Comparative Embodiment 10, the same process steps as in Embodiment 5 are used, except that no chromite or pyrite is added in S1. Other distinguishing process steps are shown in Table 1.

[0065] In Comparative Embodiment 11, the same process steps as in Embodiment 5 are used, except that no pyrite is added in S1 and the heat preservation time is 15 min. Other distinguishing process steps are shown in Table 1.

[0066] In Comparative Embodiment 12, the same process steps as in Embodiment 5 are used, except that no pyrite is added in S1 and the heat preservation time is 25 min. Other distinguishing process steps are shown in Table 1.

[0067] In Comparative Embodiment 13, the same process steps as in Embodiment 5 are used, except that the mass of the pyrite added in S1 is 0.5% of the total mass of aluminum powder and silicon carbide particles, and the heat preservation time is 15 min. Table 1 Specific process differences and performance test results of Embodiments and Comparative EmbodimentsSerial numberFormulationCleaned or notMixing methodSiC volume fractionSintering temperature / °CUnit area pressure MPaSet heat preservation time / minActual densityRelative densityPerformance test resultsEmbodiment 1Graded silicon carbide (10-12:25-30=3.5:6.5)+AlNoWet mixing55.00%58020102.94998.65%Flexural strength 383.5 MPa, Thermal conductivity 233 W / (m.k)Coefficient of thermal expansion 13.5×10 -6< KEmbodiment 2Graded silicon carbide (10-12:25-30=3:7)+AlNoWet mixing55.00%56040152.93898.97%Flexural strength 386.2 MPa, Thermal conductivity 232.7 W / (m.k)Coefficient of thermal expansion 13.7×10 -6< KEmbodiment 3Graded silicon carbide (10-12:25-30=3:7)+AlYesWet mixing55.00%56040102.96199.14%Flexural strength 382.5 MPa, Thermal conductivity 236.5 W / (m.k)Coefficient of thermal expansion 13.6×10 -6< KEmbodiment 4Graded silicon carbide (10-12:25-30=4:6)+AlYesWet mixing52%58030152.96999.31%Flexural strength 388.5 MPa, Thermal conductivity 241.3 W / (m.k)Coefficient of thermal expansion 13.2×10 -6< KEmbodiment 5Graded silicon carbide (10-12:25-30=3.5:6.5)+AlYesWet mixing60%56020152.98699.24%Flexural strength 391.2 MPa, Thermal conductivity 234 W / (m.k)Coefficient of thermal expansion 12.9×10 -6< KComparative Embodiment 110-12 SiC+AlNoDry mixing35.00%60040102.77596.35%Comparative Embodiment 210-12 SiC+AlNoDry mixing45.00%60020102.82696.45%Comparative Embodiment 310-12 SiC+AlNoDry mixing45.00%60040102.83196.62%Comparative Embodiment 410-12 SiC+AlNoDry mixing55.00%60040102.74091.64%Comparative Embodiment 510-12 SiC+AlNoDry mixing65.00%60040102.57184.57%Comparative Embodiment 6Graded silicon carbide (10-12:25-30=3:7)+AlNoDry mixing55.00%60040102.88396.43%Comparative Embodiment 7Graded silicon carbide (10-12:25-30=3:7)+AlNoDry mixing55.00%65040102.92697.87%High temperature of 650 °C, "sweating" occurs, leading to uneven material compositionComparative Embodiment 8Graded silicon carbide (10-12:25-30=3:7)+AlNoDry mixing55.00%63040102.91797.57%"Sweating" occurs, aluminum seeps out of the moldComparative Embodiment 9Graded silicon carbide (10-12:25-30=3.5:6.5)+AlNoWet mixing60.00%56020152.93498.1%Flexural strength 361.4 MPa, Thermal conductivity 229 W / (m.k)During ball milling, no polyvinylpyrrolidone is added, but 0.5% of chromite and 1% of pyrite are addedCoefficient of thermal expansion 14.1×10 -6< KComparative Embodiment 10Graded silicon carbide (10-12:25-30=3.5:6.5)+AlNoWet mixing60.00%56020152.93798.6%Flexural strength 354.1 MPa, Thermal conductivity 224 W / (m.k)During ball milling, 0.5% of polyvinylpyrrolidone is added, but no chromite or pyrite is addedCoefficient of thermal expansion 14.5×10 -6< KComparative Embodiment 11Graded silicon carbide (10-12:25-30=3.5:6.5)+AlYesWet mixing60.00%56020152.97198.74%Flexural strength 369.5 MPa, Thermal conductivity 228.2 W / (m.k)No pyrite is addedCoefficient of thermal expansion 13.9×10 -6< KComparative Embodiment 12Graded silicon carbide (10-12:25-30=3.5:6.5)+AlYesWet mixing60.00%56020252.97298.79%Flexural strength 373.3 MPa, Thermal conductivity 228.9 W / (m.k)No pyrite is addedCoefficient of thermal expansion 13.9×10 -6< KComparative Embodiment 13Graded silicon carbide (10-12:25-30=3.5:6.5)+Al 0.5% of pyrite is addedYesWet mixing60.00%56020152.97498.85%Flexural strength 380.1 MPa,Thermal conductivity 234.5 W / (m.k)Coefficient of thermal expansion 13.8×10 -6< K

[0068] The thermal conductivity, flexural strength, and coefficient of thermal expansion of composite material samples prepared in the Embodiments and Comparative Embodiments with a relative density exceeding 98% are measured respectively, while samples with a relative density below 98% in Comparative Embodiments are not measured. FIG. 2, FIG. 3, and the test results in Table 1 reveal that:

[0069] In Comparative Embodiments 1-8, no chromite, pyrite, or polyvinylpyrrolidone is added, and dry mixing is employed instead of the wet mixing process in S2. As a result, the relative densities of the prepared composite material products are generally low, and the distribution of the ceramic particles and aluminum powder is uneven. Moreover, Comparative Embodiments 7 and 8 employ a sintering temperature exceeding 600 °C, during which an obvious "sweating" phenomenon occurs, affecting the uniformity of distribution and the shape of the product.

[0070] The composite material sample obtained in Embodiment 1 as shown in FIG. 2 exhibits a smooth surface and uniform distribution of various components. The composite material sample obtained in Embodiment 3 as shown in FIG. 3 exhibits a smooth surface, no obvious graininess, delicate texture, and uniform color. As shown in FIG. 4, the surface of the composite material sample obtained in Comparative Embodiment 6 has black spots, indicating that the raw materials are not completely mixed uniformly. After polishing, the material surface shows uneven texture, indicating that the interfacial bonding during sintering is not ideal. Therefore, comparing the test results of Comparative Embodiments 1-8 with Embodiment 1, it can be seen that using wet mixing in step S2 and adding polyvinylpyrrolidone during ball milling can effectively improve the dispersion uniformity of the raw materials.

[0071] Comparing the performance test results of the composite materials in Embodiment 5 and Comparative Embodiment 10, it can be seen that after adding polyvinylpyrrolidone, the relative density of the composite material is significantly improved. The electron microscopy image of the composite material prepared in Embodiment 5 at a scale of 100 µm, as shown in FIG. 5, reveals that the composite material exhibits good density, no obvious pores, and relatively uniform particle distribution. The electron microscopy image of the composite material prepared in Comparative Embodiment 9 at a scale of 100 µm, as shown in FIG. 6, shows obvious uneven particle distribution and high porosity. This indicates that the absence of polyvinylpyrrolidone during ball milling mixing has an adverse effect on the particle dispersion of the prepared composite material.

[0072] Comparing the performance test results of the composite materials in Embodiment 5 and Comparative Embodiment 9, indicates that the addition of chromite and pyrite significantly enhances both the flexural strength and thermal conductivity of the composite material.

[0073] Moreover, in Comparative Embodiments 1-5, only silicon carbide particles of a single particle size are used, and dry mixing is employed in S2, resulting in a relatively low relative density. In Comparative Embodiments 4 and 5, the volume fraction of silicon carbide particles introduced during preparation is above 55%. Compared to the samples with low volume fractions in Comparative Embodiments 1-3, the samples in Comparative Embodiments 4 and 5 exhibit even lower relative densities. This is because the ceramic particles exist as discrete particles within the composite material. The higher the proportion of ceramic particles, the lower the densification of the composite material. Comparing the test results of Comparative Embodiments 4 and 5 and Comparative Embodiment 6, it can be seen that using graded silicon carbide particles as a reinforcing phase can avoid reduced densification caused by the ceramic particles of a single particle size, thereby effectively improving the density of the composite material. From the results of Comparative Embodiments 4-6, it can be seen that when using the ceramic particles of a single particle size to prepare composite materials, it is difficult to obtain composite materials with both a high volume fraction of silicon carbide and high densification.

[0074] Compared to Comparative Embodiments 4 and 5, Comparative Embodiments 6-8 use the same graded silicon carbide particles as in the Embodiments of the present disclosure, with the volume fraction of 55%. Although the performance of the resulting products is lower than that of the products prepared in the Embodiments, the relative density of the products in Comparative Embodiments 6-8 is significantly higher than that in Comparative Embodiments 4 and 5. This indicates that the graded design of silicon carbide with two particle sizes can significantly improve the densification of the product and enable the incorporation of a greater amount of reinforcing phase into the composite material, thereby reducing the coefficient of thermal expansion of the composite material.

[0075] In Comparative Embodiment 11, no pyrite is added, and the hot pressing sintering duration is 15 min; in Comparative Embodiment 12, no pyrite is added, and the hot pressing sintering duration is 25 min; in Comparative Embodiment 13, the mass of added pyrite is 0.5% of the total mass of aluminum powder and silicon carbide particles, and the hot pressing sintering duration is set to 25 min. Comparing the product performance test data of Embodiment 5 and Comparative Embodiments 11-13, it can be seen that the relative density of the product in Comparative Embodiment 12 is higher than that in Comparative Embodiment 11, indicating that increasing the hot pressing sintering duration to 25 min is beneficial to improving the densification of the product. Comparing the test data of Comparative Embodiment 12 and Comparative Embodiment 13, it can be seen that after adding pyrite in Comparative Embodiment 13, the relative density achieved with a hot pressing sintering duration of 15 min exceeds that in Comparative Embodiment 12 without pyrite under the same hot pressing sintering duration of 15 min. In Comparative Embodiment 13, pyrite is added in an amount of 0.5% by mass of the total mass of aluminum and ceramic particles, but the performance test data of the resulting product is inferior to those in Embodiment 5. This indicates that adding an appropriate amount of pyrite can effectively reduce the required hot pressing sintering time.

[0076] When the volume fraction of silicon carbide particles is 55.00%, among the samples obtained using the same process steps, comparing Embodiment 2 and Embodiment 3, in Embodiment 2, the silicon carbide particles are directly wet-milled with the aluminum powder without cleaning, achieving a density of 98.97%, a flexural strength of 386.2 MPa, a thermal conductivity of 232.7 W / (m.k), and a coefficient of thermal expansion of 13.7×10 -6< K. In Embodiment 3, the silicon carbide particles are first cleaned and dried before being wet-milled with the aluminum powder, achieving a density of 99.14%. It is evident that the ultrasonic cleaning step for the silicon carbide particles improves the relative density of the sample. Compared to the Comparative Embodiments, Embodiment 2 still exhibits significantly better performance, indicating that by the preparation method provided in the embodiments of the present disclosure, products with improved performance can be obtained even without the silicon carbide cleaning step. However, after adding the silicon carbide cleaning step S0 in Embodiment 3, the product performance can be further enhanced. By adjusting various process parameters, the relative density can reach 99.2% in the optimal embodiment (Embodiment 5).

[0077] The technical features of the above embodiments can be combined arbitrarily. For the purpose of simplicity in description, all possible combinations of the technical features in the above embodiments are not described. However, as long as the combinations of these technical features do not have contradictions, they shall fall within the scope of this specification.

[0078] The above embodiments express only several implementations of the present disclosure, and their descriptions are more specific and detailed, but should not be understood as limiting the scope of the invention. It should be noted that a person of ordinary skill in the art can further make variations and improvements without departing from the conception of the present disclosure, and these all fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be subject to the appended claims.

[0079] The content not described in detail in this specification belongs to the prior art known to professionals in the art.

Claims

1. A preparation method of a ceramic-reinforced aluminum-based composite material, comprising the following steps: S1, adding silicon carbide grinding balls and a second solvent to an aluminum powder, silicon carbide particles, a chromite, and a pyrite, and performing first-stage ball milling mixing, wherein the silicon carbide particles consist of first silicon carbide particles and second silicon carbide particles in a volume ratio of (3-4):(6-7), the first silicon carbide particles have a particle size of 10-12 µm, the second silicon carbide particles have a particle size of 25-30 µm, a volume of the silicon carbide particles accounts for 55%-60% of a total volume of the silicon carbide particles and the aluminum powder, and the aluminum powder has a particle size of 1-10 µm; S2, adding polyvinylpyrrolidone to a mixture from the ball milling in S1, and performing second-stage ball milling mixing; S3, mixing and then drying the mixture obtained from S2; and S4, performing hot pressing sintering on the mixture obtained from S3 at a temperature of 560-580 °C, a pressure of 20-40 MPa, and a heat preservation time of 10-15 min.

2. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, further comprising: S0, ultrasonically cleaning the silicon carbide particles in a first solvent, and then drying the cleaned particles, wherein the first solvent comprises one of alcohol or deionized water; the ultrasonic cleaning is carried out once or twice, with each cleaning lasting 1-30 min; and the drying after cleaning is carried out at a temperature of 80-120 °C for 4-6 h.

3. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, wherein in S1, a mass of the chromite is 0.5%-1% of a total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

4. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, wherein in S1, a mass of the pyrite is 1%-2% of the total mass of the silicon carbide particles and the aluminum powder, with a particle size of 15-25 µm.

5. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, wherein in S1, the second solvent comprises alcohol, a mass ratio of the raw materials to the second solvent is 2:1, and a mass ratio of the raw materials to the silicon carbide grinding balls is 1:2.

6. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 5, wherein in S1, the silicon carbide grinding balls comprise first particle size grinding balls and second particle size grinding balls in a mass ratio of 1:1, the first particle size grinding balls have a particle size of 2-3 mm, and the second particle size grinding balls have a particle size of 8-9 mm.

7. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, wherein in S2, a mass of the polyvinylpyrrolidone is 0.3%-1% of the total mass of the silicon carbide particles and the aluminum powder.

8. The preparation method of a ceramic-reinforced aluminum-based composite material according to any one of claims 5 to 7, wherein in S1, the first-stage ball milling is carried out at a rotational speed of 220-300 r / min for 1-1.5 h; in S2, the second-stage ball milling is carried out at a rotational speed of 300-350 r / min for 1-1.5 h.

9. The preparation method of a ceramic-reinforced aluminum-based composite material according to claim 1, wherein in S3, the drying after mixing is carried out at a temperature of 70-120 °C for 8-10 h.

10. A ceramic-reinforced aluminum-based composite material, obtained by the preparation method of a ceramic-reinforced aluminum-based composite material according to any one of claims 1 to 9.

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