A micro-nano SiC particle synergistically reinforced aluminum-based composite material and its preparation method

Abstract

The present invention relates to the technical field of lightweight structural composite material preparation, and specifically to a SiC particle reinforced aluminum-based composite material and a preparation method thereof. The preparation method comprises: (1) dispersing SiC nanoparticles; (2) uniformly welding the dispersed SiC nanoparticles on the surface of aluminum powder; (3) uniformly mixing SiC micron particles with aluminum powder with SiC nanoparticles welded on the surface; and (4) hot pressing and sintering. The present invention proposes uniformly welding SiC nanoparticles on the surface of aluminum powder and then mixing them with SiC micron particles to obtain a micro-nano SiC particle synergistically reinforced aluminum-based composite material. The present invention not only solves the problem of the difficulty of dispersing SiC nanoparticles in the aluminum matrix, but also the SiC nanoparticles on the surface of the aluminum powder can play a joint reinforcing role with the SiC micron particles to improve the mechanical properties of the aluminum-based composite material. At the same time, a rough interface structure is formed between the SiC micron particles and the aluminum matrix, which increases the interface slip loss. The product of the present invention is improved in both mechanical and damping properties.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing lightweight structural composite materials, and in particular to a micro-nano multi-scale SiC particle reinforced aluminum-based composite material and a preparation method thereof. Background Art

[0002] With the continuous development of high-tech fields such as weaponry, aerospace, and transportation, higher requirements are being placed on the performance of metal materials, which makes traditional metal materials very unsatisfactory. Adding high-performance reinforcements such as fibers, whiskers, and ceramic particles to metal matrix materials to prepare metal matrix composites can not only greatly improve the mechanical properties of single-phase metal materials, but also give full play to the low thermal expansion coefficient, thermal conductivity, electrical conductivity and other characteristics of the reinforcements to improve other properties of the metal materials. Among the many reinforcements, ceramic particle reinforced metal matrix composites have high specific strength and specific stiffness, as well as many other excellent properties, and have low anisotropy and are easy to prepare and process. Therefore, they have great application potential and have always been the focus of research in the field of metal matrix composites.

[0003] Silicon carbide (SiC) particles, as a type of ceramic particles, are low-cost, widely available, and have excellent performance. They are often used as reinforcements for metal-based composites. Aluminum-based composites reinforced with silicon carbide particles have high specific strength and specific stiffness, good dimensional stability, and excellent wear resistance and high temperature resistance. They are often used as structural materials for aerospace vehicles. However, with the continuous development of aerospace technology, higher requirements are placed on the performance of aircraft. This requires that the material not only have excellent mechanical properties to play a good load-bearing role, but also require the material to have excellent damping and vibration absorption properties to be able to resist the vibration interference of the external environment. In order to enable silicon carbide particle-reinforced aluminum-based composites to be better applied to aerospace structures, it is necessary to improve the damping performance of silicon carbide particle-reinforced aluminum-based composites.

[0004] Patent number CN201610589486 discloses a method for preparing a high-volume-fraction SiC particle-reinforced aluminum-based composite material using SPS. The method includes the following steps: 1. Weigh 25-55% SiC particles and 45-75% aluminum powder; 2. Place the SiC particles and aluminum powder in a ball mill and mill them to form a mixed powder; 3. Mix the mixed powder with a binder and then pass it through a 60-100 mesh sieve for granulation; 4. Cold press the powder to form a green blank; and 5. Sinter the green blank. The binder in step 3 is a mixture of ethyl acetate and cellulose, with a volume ratio of ethyl acetate to cellulose of 10:1. The existing problems are: 1. The obtained SiC particle reinforced aluminum-based composite material only improves the mechanical properties, but does not achieve an improvement in its damping performance. During the use of aluminum-based composite materials, especially for aerospace devices, their failure often occurs under vibration and noise conditions. Therefore, poor damping performance will directly lead to problems in the structure of aerospace devices, resulting in poor reliability and low working precision; 2. Since no dispersion liquid is used for pre-dispersion and hydroxyethyl cellulose welding material is adsorbed on the surface of the nano-SiC particles, it is difficult to effectively disperse and weld the nano-SiC particles using this method.

[0005] Therefore, it is necessary to find new methods to prepare silicon carbide particle reinforced aluminum matrix composites so that they not only have high mechanical properties but also excellent damping and vibration absorption properties. Summary of the Invention

[0006] The present invention aims to provide a SiC particle reinforced aluminum-based composite material with damping, vibration absorption and load-bearing functions and a preparation method thereof, so as to solve the problem that the existing technology is difficult to simultaneously improve the damping and mechanical properties of SiC particle reinforced aluminum-based composite materials. When mechanical equipment is subjected to high-intensity vibration and noise, there are problems of poor reliability and low working precision.

[0007] To achieve the purpose of the present invention, the technical solution adopted by the present invention is: a method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material, comprising the following steps:

[0008] (1) Dispersing SiC nanoparticles: First, hydroxypropyl cellulose is added to anhydrous ethanol and stirred thoroughly to dissolve it to prepare a dispersion liquid, wherein the mass ratio of hydroxypropyl cellulose to anhydrous ethanol is 1:180-1:260; then, SiC nanoparticles with a particle size of 50-100 nm are added to the dispersion liquid, wherein the mass ratio of SiC nanoparticles to dispersion liquid is 1:46, and stirred and dispersed uniformly to obtain a SiC nanoparticle solution;

[0009] (2) Welding SiC nanoparticles onto the surface of aluminum powder: taking a SiC nanoparticle solution with a mass ratio of 5:6 and aluminum powder with a particle size of 30-100 μm, ball milling them in a high-energy ball mill, and then drying them to obtain aluminum powder with SiC nanoparticles welded on the surface;

[0010] (3) Uniform mixing: first, polyethyleneimine is placed in anhydrous ethanol and stirred thoroughly to completely dissolve it. The mass ratio of polyethyleneimine to anhydrous ethanol is 1:40, and the mixture is allowed to stand at room temperature for 12 hours to obtain a mixed solution. Then, aluminum powder with surface-welded SiC nanoparticles and micron SiC particles are mixed at a mass ratio of 2-5:1 to obtain a powder mixture. The mixed solution and powder mixture with a volume ratio of 4:1 are measured, stirred, and then filtered to obtain a uniform mixture of SiC micron particles and aluminum powder with surface-welded SiC nanoparticles.

[0011] (4) Hot pressing sintering: The uniformly mixed SiC micron particles and aluminum powder with SiC nanoparticles welded on the surface are placed in a graphite grinding tool and sintered at high temperature in a vacuum hot pressing sintering furnace.

[0012] Furthermore, in the above step 1, the stirring is performed by mechanical stirring at a speed of 500-800 rpm for 30 minutes, and the dispersion is performed by ultrasonic oscillation dispersion at a power of 400-800 W for 1 hour.

[0013] Furthermore, in the above step 2, the grinding ball medium is a tungsten carbide ball with a diameter of 3 mm, the ball mill container is a cemented carbide ball mill, the mass ratio of grinding balls to raw materials is 10:1, the ball mill speed is 250 rpm, and the ball milling time is 4.5 h. After the ball milling is completed, the drying is performed by using a circulating water vacuum pump to extract and evaporate excess dispersant in the powder.

[0014] Furthermore, in the above step 3, the stirring is mechanical stirring at a speed of 500 rpm for 30 minutes, and the filtration is pouring the evenly mixed powder solution into a suction filtration device, and quickly filtering out excess mixed liquid under the action of a suction pump to obtain an evenly mixed SiC micron particle and aluminum powder with surface-welded nanoparticles.

[0015] Furthermore, in the above step 4, the sintering process is to extract the vacuum degree to 10 -2 Pa, heat the furnace chamber temperature to 660-700℃, keep it warm for 10-15min, then pressurize it at 8-15MPa for sintering for 3-8min, and then cool it to room temperature.

[0016] Furthermore, in the above step (3), the particle size of the SiC micron particles is 5-10 μm.

[0017] Furthermore, the present invention provides a micro-nano SiC particle synergistically reinforced aluminum-based composite material prepared by the above preparation method.

[0018] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0019] 1. The preparation method of the present invention is simple and easy: it proposes to improve the damping and mechanical properties of SiC particle-reinforced aluminum-based composites through micro-nano synergistic strengthening. The specific analysis is as follows: Since the nanoparticles are extremely small in size and have a high surface activity, they are easily agglomerated with each other. The present invention first uses an ethanol solution of hydroxypropyl cellulose as a dispersant to achieve uniform dispersion of SiC nanoparticles. Then, a ball milling welding method is adopted. During the ball milling welding process, the hydroxypropyl cellulose in the dispersant serves as a welding agent. Due to the presence of non-polar groups in the hydroxypropyl cellulose, it can form an adsorption effect between the surface of the aluminum powder and the nano-SiC, thereby firmly welding the SiC nanoparticles to the aluminum powder surface, thereby preventing the SiC nanoparticles from falling off and agglomerating during the subsequent mixing process with the SiC micron particles.

[0020] 2. Synchronous improvement of the mechanical and damping properties of the composite material: Using the method of the present invention, the SiC nanoparticles are more evenly distributed on the surface of the aluminum powder. On the one hand, they can work together with the SiC micron particles to enhance the mechanical properties of the aluminum-based composite material. On the other hand, the SiC nanoparticles form a rough interface structure between the SiC micron particles and the aluminum matrix, which increases the interface slip loss. Under the action of external vibration, the vibration energy can be quickly consumed, thereby increasing the damping and vibration absorption performance of the aluminum-based composite material. As a result, the mechanical and damping properties of the SiC particle-reinforced aluminum-based composite material of the present invention are simultaneously improved.

[0021] 3. The micro-nano SiC particle synergistically reinforced aluminum-based composite material prepared by the present invention has excellent mechanical and damping properties due to the synergistic strengthening effect of micron and nano SiC particles. The density of the composite material is 2.72g / cm 3 The tensile strength is 260 MPa; the elastic modulus is 96 GPa, and the average damping value at 25-300 ° C is 25.1×10 -3 , with high strength, stiffness, and high damping performance. It can effectively improve the reliability and working accuracy of aerospace components in the presence of vibration and noise, and its applicability in aerospace structural parts has been greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the surface-welded SiC nanoparticle aluminum powder obtained in the embodiment;

[0023] Figure 2 This is a scanning electron microscope image of the aluminum-based composite material synergistically reinforced with micro-nano SiC particles obtained in the embodiment;

[0024] Figure 3 This is a macroscopic photograph of the aluminum-based composite material synergistically reinforced by micro-nano SiC particles obtained in the example. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0026] Example 1: A method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material provided by the present invention comprises the following steps:

[0027] Step 1: Add hydroxypropyl cellulose to anhydrous ethanol and stir thoroughly to dissolve it to prepare a dispersion liquid capable of dispersing SiC nanoparticles, wherein the mass ratio of hydroxypropyl cellulose to anhydrous ethanol is 1:180. Next, add SiC nanoparticles with a particle size of 100 nm to the dispersion liquid, and the mass ratio of SiC nanoparticles to dispersion liquid is 1:46. The mixture is mechanically stirred at a speed of 500 rpm for 30 minutes, and then dispersed by ultrasonic oscillation at an ultrasonic power of 400 W for 1 hour to uniformly disperse the SiC nanoparticles in the dispersion liquid, thereby obtaining a SiC nanoparticle solution.

[0028] Step 2: The SiC nanoparticles dispersed in step 1 and 1060 aluminum powder with a particle size of 100 μm are placed in a ball mill and ball milled in a high-energy ball mill. Under the action of impact and extrusion, the SiC nanoparticles are evenly welded to the surface of the aluminum powder. The mass ratio of the liquid in which the SiC nanoparticles are dispersed to the aluminum powder is 5:6. The grinding ball medium is a tungsten carbide ball with a diameter of 3 mm. The ball mill container is a cemented carbide ball mill. The ratio of grinding balls to raw materials is 10:1. The ball mill speed is 250 rpm and the ball milling time is 4.5 hours. After the ball milling is completed, the powder is dried and the excess dispersant in the evaporated powder is extracted using a circulating water vacuum pump to obtain aluminum powder with SiC nanoparticles welded on the surface.

[0029] Step 3: First, a certain mass of polyethyleneimine is weighed and placed in anhydrous ethanol. The mixture is stirred thoroughly to completely dissolve the polyethyleneimine, with the mass ratio of polyethyleneimine to anhydrous ethanol being 1:40. The mixture is then allowed to stand at room temperature for 12 hours to form a stable mixed solution. Next, aluminum powder with surface-welded SiC nanoparticles and micronized SiC particles are mixed at a mass ratio of 5:1 to obtain a powder mixture, with the SiC micronized particles having a particle size of 10 μm. The mixed solution is measured and poured into a beaker, and the powder mixture is added to the beaker at a volume ratio of 4:1. The mixture is stirred at 500 rpm for 30 minutes to uniformly disperse the powder in the mixed solution. The uniformly mixed powder solution is then poured into a filtration device, and the excess mixed solution is quickly filtered out using a filtration pump to obtain a uniform mixture of SiC micronized particles and aluminum powder with surface-welded SiC nanoparticles.

[0030] Step 4: Place the SiC micron particles mixed evenly in step 3 and the aluminum powder with surface-welded nanoparticles into a graphite grinder and sinter them at high temperature in a vacuum hot pressing sintering furnace. The sintering process is to extract the vacuum degree to 10-2 Pa, the furnace chamber temperature is heated to 660℃, kept warm for 15min, and then sintered under pressure of 15MPa for 8min, then cooled to room temperature and the material is taken out from the graphite grinding tool.

[0031] Example 2, a method for preparing a SiC particle reinforced aluminum-based composite material, comprising the following steps:

[0032] Step 1: Add hydroxypropyl cellulose to anhydrous ethanol and stir thoroughly to dissolve it to prepare a dispersion liquid capable of dispersing SiC nanoparticles, wherein the mass ratio of hydroxypropyl cellulose to anhydrous ethanol is 1:260. Next, add SiC nanoparticles with a particle size of 50 nm to the dispersion liquid, and the mass ratio of SiC nanoparticles to dispersion liquid is 1:46. Mechanical stirring is performed at a speed of 800 rpm for 30 minutes, and then ultrasonic oscillation dispersion is performed at an ultrasonic power of 800 W for 1 hour to uniformly disperse the SiC nanoparticles in the dispersion liquid to obtain a SiC nanoparticle solution.

[0033] Step 2: The SiC nanoparticles dispersed in step 1 and 60 μm 6061 aluminum powder are placed in a ball mill and ball milled in a high-energy ball mill. Under the action of impact and extrusion, the SiC nanoparticles are evenly welded to the surface of the aluminum powder. The mass ratio of the liquid in which the SiC nanoparticles are dispersed to the aluminum powder is 5:6. The grinding ball medium is a tungsten carbide ball with a diameter of 3 mm. The ball mill container is a cemented carbide ball mill. The ratio of grinding balls to raw materials is 10:1. The ball mill speed is 250 rpm and the ball milling time is 4.5 hours. After the ball milling is completed, the powder is dried and the excess dispersant in the evaporated powder is extracted using a circulating water vacuum pump to obtain aluminum powder with SiC nanoparticles welded on the surface.

[0034] Step 3: First, a certain mass of polyethyleneimine is weighed and placed in anhydrous ethanol, and stirred thoroughly to completely dissolve it. The mass ratio of polyethyleneimine to anhydrous ethanol is 1:40. Then, the mixture is allowed to stand at room temperature for 12 hours to form a stable mixed solution. Then, aluminum powder with surface-welded SiC nanoparticles and micronized SiC particles are mixed in a mass ratio of 2:1 to obtain a powder mixture. The SiC micronized particles have a particle size of 5 μm. The mixed solution is measured and poured into a beaker, and the powder mixture is added to the beaker. The volume ratio of the mixed solution to the powder mixture is 4:1. The mixture is stirred for 30 minutes under mechanical stirring at 500 rpm to uniformly disperse the powder in the mixed solution. The uniformly mixed powder solution is then poured into a filtration device. The excess mixed solution is quickly filtered out using a filtration pump to obtain a uniform mixture of SiC micronized particles and aluminum powder with surface-welded SiC nanoparticles.

[0035] Step 4: Place the SiC micron particles mixed evenly in step 3 and the aluminum powder with surface-welded nanoparticles into a graphite grinder and sinter them at high temperature in a vacuum hot pressing sintering furnace. The sintering process is to extract the vacuum degree to 10-2 Pa, the furnace chamber temperature is heated to 680℃, kept warm for 10 minutes, and then sintered under pressure of 10MPa for 6 minutes, then cooled to room temperature and the material is taken out from the graphite grinding tool.

[0036] The above embodiment 2 is the best embodiment. Figure 1 , the aluminum powder with SiC nanoparticles welded on the surface obtained in Example 2, it can be seen that the SiC nanoparticles are firmly welded on the surface of the aluminum powder.

[0037] See also Figure 2 and Figure 3 The microscopic and macroscopic photos of the micro-nano SiC particles synergistically reinforced aluminum-based composite material obtained in Example 2 show that the prepared composite material has a dense structure.

[0038] The composite material obtained in Example 2 was tested and the obtained data showed that its density was 2.72 g / cm 3 The tensile strength is 260 MPa; the elastic modulus is 96 GPa, and the average damping value at 25-300 ° C is 25.1×10 -3 The micro-nano SiC particle synergistically reinforced aluminum-based composite material of the present invention has excellent mechanical and damping properties.

[0039] The present invention is further described above in conjunction with the embodiments, but the present invention is not limited to the above-mentioned embodiments. Within the scope of knowledge possessed by ordinary technicians in this field, any simple modifications, equivalent changes and modifications made to the above embodiments without departing from the purpose of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material, characterized in that: The steps include: (1) Dispersing SiC nanoparticles: First, hydroxypropyl cellulose is added to anhydrous ethanol and stirred thoroughly to dissolve it to prepare a dispersion liquid, with the mass ratio of hydroxypropyl cellulose to anhydrous ethanol being 1:180-1:260; then, SiC nanoparticles with a particle size of 50-100 nm are added to the dispersion liquid, with the mass ratio of SiC nanoparticles to dispersion liquid being 1:46, and stirred to disperse uniformly to obtain a SiC nanoparticle solution; (2) Welding SiC nanoparticles to the surface of aluminum powder: taking a SiC nanoparticle solution with a mass ratio of 5:6 and aluminum powder with a particle size of 30-100 μm, ball milling them in a high-energy ball mill, and then drying them to obtain aluminum powder with SiC nanoparticles welded on the surface; (3) Uniform mixing: First, put polyethyleneimine into anhydrous ethanol and stir it thoroughly to dissolve it completely. The mass ratio of polyethyleneimine to anhydrous ethanol is 1:

40. Let it stand at room temperature for 12 hours. Then, mix the aluminum powder with SiC nanoparticles welded on the surface with micron SiC particles at a mass ratio of 2-5:1 to obtain a powder mixture. Measure the mixed liquid and powder mixture with a volume ratio of 4:1, stir and filter to obtain a uniform mixture of SiC micron particles and aluminum powder with SiC nanoparticles welded on the surface. (4) Hot pressing sintering: The uniformly mixed SiC micron particles and aluminum powder with SiC nanoparticles welded on the surface are placed in a graphite grinding tool and sintered at high temperature in a vacuum hot pressing sintering furnace.

2. The method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material according to claim 1, characterized in that: In the step 1, the stirring and dispersing is performed by mechanical stirring at a speed of 500-800 rpm for 30 minutes, and the dispersion is performed by ultrasonic oscillation dispersion at a power of 400-800 W for 1 hour.

3. The method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material according to claim 2, characterized in that: In step 2, the grinding ball medium is a tungsten carbide ball with a diameter of 3 mm, the ball mill container is a cemented carbide ball mill, the mass ratio of grinding balls to raw materials is 10:1, the ball mill speed is 250 rpm, and the ball milling time is 4.5 h. After the ball milling is completed, the drying is performed by using a circulating water vacuum pump to extract and evaporate the excess dispersant in the powder.

4. The method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material according to claim 3, characterized in that: In step 3, the stirring and filtering are performed, and the stirring is mechanical stirring at a speed of 500 rpm for 30 minutes. The filtration is to pour the uniformly mixed powder solution into a filtration device, and quickly filter out the excess mixed liquid under the action of a filtration pump to obtain a uniform mixture of SiC micron particles and aluminum powder with surface-welded nanoparticles.

5. The method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material according to claim 4, characterized in that: In the step 4, the sintering process is to extract the vacuum degree to 10 -2 Pa, heat the furnace chamber temperature to 660-700℃, keep it warm for 10-15min, then pressurize it at 8-15MPa for sintering for 3-8min, and then cool it to room temperature.

6. The method for preparing a micro-nano SiC particle synergistically reinforced aluminum-based composite material according to claim 5, characterized in that: The particle size of the SiC micron particles in step (3) is 5-10 μm.

7. A micro-nano SiC particle synergistically reinforced aluminum-based composite material prepared by the preparation method according to claim 1.

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