SiC particle reinforced aluminum-based composite material and preparation method thereof

Abstract

The invention relates to a SiC particle reinforced aluminum-based composite material and a preparation method thereof, and belongs to the technical field of metal-based composite materials. The composite material comprises the following components in percentage by mass: 80-90% of an aluminum alloy matrix and 10-20% of SiC particles, wherein the mass percentage of the aluminum alloy matrix is 100%; the aluminum alloy matrix comprises the following alloy elements in percentage by mass: 0.7%-1.2% of Cu, 0.6%-1.1% of Mn, 0.8%-1.1% of Mg, 0.10%-0.25% of Zn, 0.10%-0.4% of Cr, 0.1%-0.2% of Ti, 0.9%-1.8% of Si, 0.1%-0.5% of Fe and the balance of aluminum. SiC particles are introduced into an aluminum matrix after being subjected to surface modification treatment by a KH560 silane coupling agent, so that the surface energy of the SiC particles is effectively reduced, and the wettability and dispersion uniformity of the SiC particles in the matrix are improved. The modified SiC particles can inhibit growth of alpha (Al) crystal grains in the composite material, refine the organization structure, play a role in strengthening by hindering dislocation motion and bearing external load, and realize synergy of dispersion strengthening and load strengthening. The material disclosed by the invention has relatively high rigidity and mechanical property, and is suitable for a structure application scene with relatively high requirements on light weight and high strength.

Description

Technical Field

[0001] The present invention relates to a SiC particle-reinforced aluminum matrix composite material and a preparation method thereof, belonging to the technical field of metal matrix composite materials. Background Art

[0002] Al-Mg-Si series aluminum alloys have been widely used in the field of automotive lightweight due to their low density, good casting performance, strong wear resistance, high dimensional stability and low cost. However, solely relying on alloy element regulation to improve their strength and toughness has gradually faced bottlenecks.

[0003] Therefore, using ceramic particle-reinforced aluminum matrix composite materials has become an effective solution. Such materials have high specific strength, high specific stiffness and excellent thermal stability. The particle reinforcement can not only refine grains, introduce dislocations, but also significantly improve the heat treatment strength of the alloy, thereby improving the overall performance. However, there are still two key problems in the prior art: one is the poor wettability between ceramic particles and the aluminum matrix, and the other is the uneven distribution of reinforcing particles in the matrix, which seriously affects the consistency and performance of the material. Summary of the Invention

[0004] The present invention aims at the problem that in the existing ceramic particle-reinforced aluminum alloys, the reinforcing particles are difficult to be evenly distributed in the aluminum matrix, which in turn leads to insufficient comprehensive performance of the material, and provides a SiC particle-reinforced aluminum matrix composite material and a preparation method thereof. This method uses KH560 silane coupling agent to perform surface modification on SiC particles, introducing organic functional groups to reduce the surface energy of SiC, thereby improving the dispersibility and wettability of SiC particles in the aluminum matrix. Subsequently, the modified SiC particles are added to the aluminum alloy matrix (preferably 6606 aluminum alloy) to prepare a particle-reinforced aluminum matrix composite material. The modified SiC particles can effectively hinder the growth of α(Al) grains in the matrix, realizing grain refinement; at the same time, they can hinder dislocation movement and achieve load transfer during loading, improving the yield strength and tensile strength of the material. Through this solution, the bonding interface between the reinforcing particles and the aluminum matrix is good, and the overall mechanical properties of the composite material are significantly improved.

[0005] For a SiC particle-reinforced aluminum matrix composite material, calculated by taking the mass percentage of the composite material as 100%, the aluminum alloy matrix accounts for 80 - 90%, and SiC accounts for 10 - 20%; calculated by taking the mass percentage of the aluminum matrix as 100%, Cu accounts for 0.7 - 1.2%, Mn accounts for 0.6 - 1.1%, Mg accounts for 0.8 - 1.1%, Zn accounts for 0.10 - 0.25%, Cr accounts for 0.10 - 0.4%, Ti accounts for 0.1 - 0.2%, Si accounts for 0.9 - 1.8%, Fe 0.1 - 0.5%, and the balance is aluminum.

[0006] The preparation method of the SiC particle-reinforced aluminum matrix composite material is specifically as follows:

[0007] (1) Add KH560 silane coupling agent to absolute ethanol and mix evenly to obtain a silane coupling agent solution;

[0008] (2) Add SiC powder to the silane coupling agent solution, mix evenly, perform ball milling modification for 4 - 6 h, and dry to obtain modified SiC powder;

[0009] (3) Ball mill and mix the modified SiC powder and aluminum alloy powder to obtain a mixture powder;

[0010] (4) Press the mixture powder into a sheet to obtain a mixture sheet; preferably, the relative density of the mixture sheet is 85 - 95%, and there is no phenomenon of loose sheet, cracked sheet, or delamination;

[0011] (5) Lay alumina powder in a sintering container, place the mixture sheet on the alumina powder, and then cover it with alumina powder, and perform two - stage variable - temperature sintering to obtain a composite material blank;

[0012] (6) Heat - treat the composite material blank to obtain an age - hardened SiC particle - reinforced aluminum matrix composite material.

[0013] Preferably, the concentration of the silane coupling agent solution in step (1) is 0.05 - 0.15 g / mL.

[0014] Preferably, the specific method of the two - stage variable - temperature sintering in step (5) is as follows:

[0015] The first - stage variable - temperature sintering: The heating rate is 5 - 10 °C. When the temperature is raised to 280 - 320 °C, hold for 30 - 60 min, then continue to raise the temperature to 330 - 370 °C and hold for 30 - 60 min, then continue to raise the temperature to 380 - 420 °C and hold for 30 - 60 min, then continue to raise the temperature to 430 - 470 °C and hold for 30 - 60 min, and then cool the furnace to room temperature;

[0016] The second - stage variable - temperature sintering: The heating rate is 5 - 10 °C. When the temperature is raised to 20 - 30 °C, hold for 60 - 90 min, then continue to raise the temperature to 70 - 90 °C and hold for 120 - 150 min, then continue to raise the temperature to 110 - 130 °C and hold for 120 - 150 min, then continue to raise the temperature to 230 - 270 °C and hold for 120 - 150 min, then continue to raise the temperature to 330 - 370 °C and hold for 120 - 150 min, then continue to raise the temperature to 430 - 470 °C and hold for 60 - 90 min, and then cool the furnace to room temperature.

[0017] Preferably, the heat treatment method in step (6) is as follows: the composite material blank is heated to a temperature of 500 - 550 °C and held for 20 - 30 min for solution treatment, and then cooled to a temperature of 150 - 200 °C and held for 7 - 9 h for aging treatment.

[0018] The beneficial effects of the present invention are as follows:

[0019] (1) In the present invention, SiC particles modified by KH560 silane coupling agent are used to reinforce the aluminum alloy matrix (preferably 6606 aluminum alloy matrix). The surface energy of the modified SiC particles with long alkyl groups on the surface is reduced, improving the interfacial condition between the SiC particles and the aluminum alloy, making the combination more compact.

[0020] (2) The present invention uses two-stage variable-temperature sintering to prepare the composite material blank. The first-stage variable-temperature sintering forms an alloy matrix network. During the second-stage variable-temperature sintering, the aluminum alloy matrix fully wraps the SiC particles to avoid agglomeration, and finally the SiC particles are evenly distributed in the aluminum alloy matrix, enhancing the mechanical properties of the aluminum alloy by dispersion strengthening.

[0021] (3) The composite material blank of the present invention is heat-treated. The SiC particles play a role in hindering dislocations and load transfer in the aluminum alloy, and refine the grains. The obtained composite material has more excellent properties than ordinary aluminum alloys. Description of the Drawings

[0022] Figure 1 Schematic diagram of the mechanism of surface modification of SiC particles by KH560 silane coupling agent;

[0023] Figure 2 SEM image of the SiCp / 6066Al composite material before heat treatment in Example 1;

[0024] Figure 3 SEM image of the SiCp / 6066Al composite material after heat treatment in Example 1;

[0025] Figure 4 SEM image of the SiCp / 6066Al composite material after heat treatment in Comparative Example 1;

[0026] Figure 5 Density diagram of the SiCp / 6066Al composite materials in Examples 1 - 3 and Comparative Examples 1 - 3;

[0027] Figure 6 Vickers hardness change diagram of the SiCp / 6066Al composite materials in Examples 1 - 3 and Comparative Examples 1 - 3 before and after heat treatment. Specific Embodiments

[0028] The following further elaborates on the present invention in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the described content.

[0029] Example 1: For the SiC particle-reinforced aluminum matrix composite SiCp / 6066Al, calculated based on 100% of the mass percentage of the composite material, the aluminum alloy matrix accounts for 80%, and SiC accounts for 20%; calculated based on 100% of the mass percentage of the aluminum matrix, Cu accounts for 1.2%, Mn accounts for 1%, Mg accounts for 1%, Zn accounts for 0.25%, Cr accounts for 0.4%, Ti accounts for 0.2%, Si accounts for 1.8%, Fe accounts for 0.5%, and the balance is aluminum;

[0030] The preparation method of the SiC particle-reinforced aluminum matrix composite SiCp / 6066Al is as follows:

[0031] (1) Add KH560 silane coupling agent to absolute ethanol and mix evenly to obtain a silane coupling agent solution; the mass concentration of the silane coupling agent solution is 0.1 g / mL;

[0032] (2) Add SiC powder to the silane coupling agent solution and mix evenly, perform ball milling modification for 6 h, and dry to obtain modified SiC powder (for the schematic diagram of the mechanism of surface modification of SiC particles by KH560 silane coupling agent, see Figure 1 );

[0033] (3) Ball mill and mix the modified SiC powder and aluminum alloy powder for 4 h to obtain a mixture powder;

[0034] (4) Press the mixture powder into a sheet to obtain a mixture sheet; the relative density of the mixture sheet is 95%, and there are no phenomena such as loose sheets, cracked sheets, or delamination;

[0035] (5) Lay alumina powder in the sintering container, place the mixture sheet on the alumina powder, and then cover it with alumina powder, and perform two-stage variable-temperature sintering to obtain a composite material blank; the specific method of the two-stage variable-temperature sintering is as follows:

[0036] The first-stage variable-temperature sintering: The heating rate is 8 °C, heat up to 300 °C and hold for 60 min, continue to heat up to 350 °C and hold for 60 min, continue to heat up to 400 °C and hold for 60 min, continue to heat up to 450 °C and hold for 60 min, and then cool the furnace to room temperature;

[0037] The second-stage variable-temperature sintering: The heating rate is 8 °C, heat up to 25 °C and hold for 90 min, continue to heat up to 80 °C and hold for 150 min, continue to heat up to 120 °C and hold for 150 min, continue to heat up to 250 °C and hold for 150 min, continue to heat up to 350 °C and hold for 150 min, continue to heat up to 450 °C and hold for 90 min, and then cool the furnace to room temperature;

[0038] (6) Heat-treat the composite material blank to obtain an aged SiC particle-reinforced aluminum matrix composite material; the heat treatment method is as follows: heat the composite material blank to a temperature of 520 °C and hold for 30 min for solution treatment, and then cool to a temperature of 180 °C and hold for 8 h for aging treatment;

[0039] As Figure 2 shown, in the SiCp / 6066Al composite material before heat treatment, a large number of second-phase particles with various morphologies are distributed on the 6066Al matrix. Scanning electron microscopy (SEM) surface scan analysis shows that this type of white, irregular, and angular second phase is the reinforcing phase SiC particles. After being modified with KH560 silane coupling agent, the SiC particles are evenly distributed in the matrix, the interface of the composite material is well bonded, and no obvious particle agglomeration phenomenon is observed (see Figure 3 );

[0040] The density test results of the composite material are as Figure 5 shown, and the density reaches 93.7%. The increase in this density is mainly attributed to the enhanced interface bonding between the modified SiC particles and the aluminum matrix;

[0041] The Vickers hardness of the composite material is tested under the conditions of a load of 10 kg and a holding time of 15 s. Five to ten points are tested for each sample, and their average value is taken. The test results are shown in Figure 6 : The hardness before heat treatment is 100.2 HV, and it is increased to 111.9 HV after heat treatment, indicating that the introduction of the modified SiC particles effectively improves the anti-deformation ability of the surface micro-region of the material.

[0042] Comparative Example 1: The only difference between the comparative example and Example 1 is that unmodified SiC powder is used to replace the modified SiC powder in Example 1. The SEM image of the SiCp / 6066Al composite material after heat treatment is shown in Figure 4 , and a large number of SiC particles with irregular shapes and sharp edges are distributed on the 6066Al matrix;

[0043] The density of this composite material is tested, and the test results are as Figure 5 shown, and the density is 90.4%, which is lower than 93.7% of Example 1. It shows that the interface bonding between the unmodified SiC particles and the aluminum matrix is weak, affecting the overall densification degree;

[0044] Under the same conditions of load F = 10 kg and residence time T = 15 s, the Vickers hardness of the comparative example sample is tested. Five to ten test points are selected for each sample and their average value is taken. The test results are as Figure 6 shown: The hardness before heat treatment is 89.2 HV, and it is increased to 93.4 HV after heat treatment. Compared with the result that the hardness in Example 1 is increased from 100.2 HV to 111.9 HV, the hardness improvement amplitude of the comparative example is smaller;

[0045] In a comprehensive comparison, the improvement in the density and hardness of the composite material prepared from unmodified SiC powder is less than that of Example 1 using modified SiC particles, indicating that the modification treatment of SiC particles has an obvious positive effect on improving the material properties.

[0046] Example 2: For the SiC particle-reinforced aluminum matrix composite material SiCp / 6066Al, calculated based on 100% by mass of the composite material, the aluminum alloy matrix accounts for 85%, and SiC accounts for 15%; calculated based on 100% by mass of the aluminum matrix, Cu accounts for 1%, Mn accounts for 1%, Mg accounts for 1.1%, Zn accounts for 0.2%, Cr accounts for 0.3%, Ti accounts for 0.15%, Si accounts for 0.9%, Fe accounts for 0.4%, and the balance is aluminum;

[0047] The preparation method of the SiC particle-reinforced aluminum matrix composite material SiCp / 6066Al is as follows:

[0048] (1) Add KH560 silane coupling agent to anhydrous ethanol and mix evenly to obtain a silane coupling agent solution; the mass concentration of the silane coupling agent solution is 0.15 g / mL;

[0049] (2) Add SiC powder to the silane coupling agent solution and mix evenly, perform ball milling modification for 5 h, and dry to obtain modified SiC powder (see the schematic diagram of the mechanism of KH560 silane coupling agent surface modification of SiC particles in Figure 1 );

[0050] (3) Ball mill and mix the modified SiC powder and aluminum alloy powder for 5 h to obtain a mixture powder;

[0051] (4) Press the mixture powder into a sheet to obtain a mixture sheet; the relative density of the mixture sheet is 85%, and there is no phenomenon of loose sheet, cracked sheet, or delamination;

[0052] (5) Lay alumina powder in the sintering container, place the mixture sheet on the alumina powder, and then cover it with alumina powder, and perform two-stage variable-temperature sintering to obtain a composite material blank; the specific method of the two-stage variable-temperature sintering is as follows:

[0053] The first-stage variable-temperature sintering: The heating rate is 10 °C. When the temperature is raised to 320 °C, hold for 30 min, continue to raise the temperature to 370 °C, hold for 30 min, continue to raise the temperature to 420 °C, hold for 30 min, continue to raise the temperature to 470 °C, hold for 30 min, and then cool the furnace to room temperature;

[0054] Second-stage variable-temperature sintering: The heating rate is 10 °C. When the temperature is raised to 30 °C, it is held for 60 min. Then it continues to be heated to 90 °C and held for 120 min. Then it continues to be heated to 130 °C and held for 120 min. Then it continues to be heated to 270 °C and held for 120 min. Then it continues to be heated to 370 °C and held for 60 min. Then it continues to be heated to 450 °C and held for 90 min. Subsequently, it is cooled in the furnace to room temperature;

[0055] (6) Heat-treat the composite material blank to obtain an aged SiC particle-reinforced aluminum matrix composite material; the heat treatment method is: heat the composite material blank to 550 °C and hold for 20 min for solution treatment, and cool to 200 °C and hold for 7 h for aging treatment;

[0056] The density of the SiCp / 6066Al composite material was tested, and the results are as Figure 5 shown. Its density is 92.6%. This relatively high density is attributed to the surface modification of SiC particles by the KH560 silane coupling agent used, which significantly improves the interfacial bonding effect between SiC particles and the 6066Al matrix;

[0057] Under the test conditions of a load of 10 kg and a residence time of 15 s, the Vickers hardness of this composite material was tested. Multiple points (5 - 10) were tested for each sample, and their average value was taken to reduce errors. The test results are shown in Figure 6 : The hardness before heat treatment is 98.4 HV, and the hardness after heat treatment is increased to 105.1 HV;

[0058] Compared with before heat treatment, the hardness has increased significantly, indicating that the introduction of modified SiC particles enhances the anti-deformation ability of the material in the surface micro-region, thereby improving the overall mechanical properties.

[0059] Comparative Example 2: The only difference between the comparative example and Example 2 is that unmodified SiC powder is used to replace the modified SiC powder in Example 2;

[0060] The density of the SiCp / 6066Al composite material was tested, and the results are shown in Figure 5 , and the density is preferably 91.4%, which is lower than 92.6% in Example 2. This shows that the interfacial bonding effect between unmodified SiC particles and the 6066Al matrix is poor, thus affecting the densification degree of the material;

[0061] Compared with the hardness performance in Example 2, which increased from 98.4 HV to 105.1 HV, the improvement amplitude of this comparative example is smaller, and the overall hardness level is also lower. The results show that the mechanical properties of the composite material formed by unmodified SiC particles reinforcing the 6066Al matrix are inferior to those of the composite material using modified SiC particles, and the strengthening effect is weaker.

[0062] Example 3: For the SiC particle-reinforced aluminum matrix composite SiCp / 6066Al, calculated based on the mass percentage of the composite material being 100%, the aluminum alloy matrix accounts for 90%, and SiC accounts for 10%; calculated based on the mass percentage of the aluminum matrix being 100%, Cu accounts for 0.8%, Mn accounts for 0.6%, Mg accounts for 0.85%, Zn accounts for 0.1%, Cr accounts for 0.1%, Ti accounts for 0.1%, Si accounts for 1.0%, Fe accounts for 0.12%, and the balance is aluminum;

[0063] The preparation method of the SiC particle-reinforced aluminum matrix composite SiCp / 6066Al is as follows:

[0064] (1) Add KH560 silane coupling agent to absolute ethanol and mix evenly to obtain a silane coupling agent solution; the mass concentration of the silane coupling agent solution is 0.05 g / mL;

[0065] (2) Add SiC powder to the silane coupling agent solution, mix evenly, perform ball milling modification for 4 h, and dry to obtain modified SiC powder (for the schematic diagram of the mechanism of surface modification of SiC particles by KH560 silane coupling agent, see Figure 1 );

[0066] (3) Ball mill and mix the modified SiC powder and aluminum alloy powder for 4.5 h to obtain a mixture powder;

[0067] (4) Press the mixture powder into a sheet to obtain a mixture sheet; the relative density of the mixture sheet is 90%, and there is no phenomenon of loose sheet, cracked sheet, or delamination;

[0068] (5) Lay alumina powder in the sintering container, place the mixture sheet on the alumina powder, and then cover it with alumina powder, and perform two-stage variable-temperature sintering to obtain a composite material blank; the specific method of the two-stage variable-temperature sintering is as follows:

[0069] The first-stage variable-temperature sintering: The heating rate is 5 °C, heat up to 280 °C and hold for 50 min, continue to heat up to 330 °C and hold for 50 min, continue to heat up to 380 °C and hold for 50 min, continue to heat up to 430 °C and hold for 50 min, and then cool the furnace to room temperature;

[0070] The second-stage variable-temperature sintering: The heating rate is 5 °C, heat up to 20 °C and hold for 70 min, continue to heat up to 70 °C and hold for 130 min, continue to heat up to 110 °C and hold for 130 min, continue to heat up to 230 °C and hold for 130 min, continue to heat up to 330 °C and hold for 60 min, continue to heat up to 430 °C and hold for 90 min, and then cool the furnace to room temperature;

[0071] (6) Heat-treat the composite material blank to obtain a SiC particle-reinforced aluminum matrix composite material in the aged state; the heat treatment method is: heat the composite material blank to a temperature of 540 °C and hold for 25 min for solution treatment, and then cool to a temperature of 190 °C and hold for 9 h for aging treatment;

[0072] The density of the SiCp / 6066Al composite material was tested, and the results are as Figure 5 shown. The density is 93.3%. This relatively high density is attributed to the surface modification treatment of the SiC particles with KH560 silane coupling agent used, which enhanced the interfacial bonding ability between the SiC particles and the 6066Al matrix;

[0073] Under the conditions of a load of 10 kg and a holding time of 15 s, the Vickers hardness of this composite material was tested. 5 - 10 test points were selected for each sample and averaged to reduce the test error. The test results are as Figure 6 shown: the hardness before heat treatment was 93.6 HV, and it increased to 105.4 HV after heat treatment;

[0074] Compared with before heat treatment, the hardness increased significantly, indicating that the introduction of modified SiC particles has a positive effect on improving the hardness of the composite material, which helps to enhance the anti-deformation ability of the material in the surface micro-region, thereby improving its comprehensive mechanical properties.

[0075] Comparative Example 3: The only difference between the comparative example and Example 3 is that unmodified SiC powder is used to replace the modified SiC powder in Example 3;

[0076] The density of the prepared SiCp / 6066Al composite material was tested, and the results are as Figure 5 shown. The density is 89.9%, which is significantly lower than 93.3% in Example 3, indicating that under the condition of unmodified SiC particles, the interfacial bonding between the particles and the matrix is poor, affecting the densification degree of the material;

[0077] Under the conditions of a load of 10 kg and a holding time of 15 s, the Vickers hardness of this composite material was tested. 5 - 10 points were tested for each sample and averaged to reduce the error. The test results are as Figure 6 shown: the hardness before heat treatment was 82.3 HV, and it increased to 92.8 HV after heat treatment;

[0078] Compared with the result of increasing from 93.6 HV to 105.4 HV in Example 3, both the initial value and the increase amplitude of the hardness in this comparative example are lower. The above results further show that the mechanical properties of the composite material obtained by reinforcing the 6066Al matrix with unmodified SiC particles are significantly weaker than those when using modified SiC particles, and the strengthening effect is limited.

[0079] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A SiC particle-reinforced aluminum matrix composite, characterized in that: Based on the composite material having a mass percentage of 100%, the aluminum alloy matrix accounts for 80 - 90%, and SiC accounts for 10 - 20%; based on the aluminum matrix having a mass percentage of 100%, Cu accounts for 0.7 - 1.2%, Mn accounts for 0.6 - 1.1%, Mg accounts for 0.8 - 1.1%, Zn accounts for 0.10 - 0.25%, Cr accounts for 0.10 - 0.4%, Ti accounts for 0.1 - 0.2%, Si accounts for 0.9 - 1.8%, Fe accounts for 0.1 - 0.5%, and the balance is aluminum.

2. The preparation method of the SiC particle-reinforced aluminum matrix composite material according to claim 1, characterized in that, The specific steps are as follows: (1) Add KH560 silane coupling agent to absolute ethanol and mix evenly to obtain a silane coupling agent solution; (2) Add SiC powder to the silane coupling agent solution, mix evenly, perform ball milling modification for 4 - 6 h, and dry to obtain modified SiC powder; (3) Ball mill and mix the modified SiC powder and aluminum alloy powder to obtain a mixture powder; (4) Press the mixture powder into a sheet to obtain a mixture sheet; (5) Lay alumina powder in a sintering container, place the mixture sheet on the alumina powder, and then cover it with alumina powder, and perform two-stage variable-temperature sintering to obtain a composite material blank; (6) Heat-treat the composite material blank to obtain a SiC particle-reinforced aluminum matrix composite material in the aged state.

3. The preparation method of the SiC particle-reinforced aluminum matrix composite according to claim 2, characterized in that: In step (1), the concentration of the silane coupling agent solution is 0.05 - 0.15 g / mL.

4. The preparation method of the SiC particle-reinforced aluminum matrix composite material according to claim 2, characterized in that: The specific method of the two-stage variable-temperature sintering in step (5) is as follows: The first-stage variable-temperature sintering: The heating rate is 5 - 10 °C. When heating to a temperature of 280 - 320 °C, hold for 30 - 60 min, continue heating to a temperature of 330 - 370 °C, hold for 30 - 60 min, continue heating to a temperature of 380 - 420 °C, hold for 30 - 60 min, continue heating to a temperature of 430 - 470 °C, hold for 30 - 60 min, and then cool the furnace to room temperature; The second-stage variable-temperature sintering: The heating rate is 5 - 10 °C. When heating to a temperature of 20 - 30 °C, hold for 60 - 90 min, continue heating to a temperature of 70 - 90 °C, hold for 120 - 150 min, continue heating to a temperature of 110 - 130 °C, hold for 120 - 150 min, continue heating to a temperature of 230 - 270 °C, hold for 120 - 150 min, continue heating to a temperature of 330 - 370 °C, hold for 120 - 150 min, continue heating to a temperature of 430 - 470 °C, hold for 60 - 90 min, and then cool the furnace to room temperature.

5. The preparation method of the SiC particle-reinforced aluminum matrix composite material according to claim 2, wherein: The heat treatment method in step (6) is: Heat the composite material blank to a temperature of 500 - 550 °C and hold for 20 - 30 min for solution treatment, and cool to a temperature of 150 - 200 °C and hold for 7 - 9 h for aging treatment.

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