Powder forged SiC reinforced heterogeneous structure aluminum matrix composite and method of making

Abstract

This invention discloses a powder-forged SiC-reinforced heterostructure aluminum matrix composite material and its preparation method, belonging to the field of powder metallurgy. The invention involves mixing SiC particles, aluminum alloy powder, and aluminum alloy powder byproducts, followed by pressing, sintering, and forging to obtain an aluminum matrix composite material with a heterostructure. This heterostructure comprises three microstructures: coarse Al grains formed from aluminum alloy powder byproducts, fine Al grains formed from aluminum alloy powder, and SiC particles. The coarse Al grains formed from aluminum alloy powder byproducts are surrounded by fine Al grains formed from aluminum alloy powder, and both the coarse and fine grain regions are stabilized by the SiC particles distributed within them. This method rationally utilizes aluminum alloy powder byproducts, reducing the production cost of SiC-reinforced aluminum matrix composites while improving the utilization rate of powder byproducts. The heterostructure composite material prepared using this method has the characteristic of easily controllable grain size and coarse-fine grain ratio, and is expected to coordinately improve the strength and plasticity of aluminum matrix composites.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy, specifically to a powder-forged SiC-reinforced heterostructure aluminum matrix composite material and its preparation method. Background Technology

[0002] Powder metallurgy is a process technology that uses metal powders (or mixtures of metal and non-metal powders) as raw materials to produce metallic materials, composite materials, and various types of products. It is widely used in transportation, machinery, electronics, and aerospace industries. With the rapid expansion of the industry and the continuous upgrading of powder metallurgy technology, its application scope is constantly expanding, the demand for metal powders is continuously increasing, and the requirements for powder performance in terms of particle size, purity, morphology, and other aspects are gradually becoming more stringent. As the most important raw material in the powder metallurgy industry, powder requires a large amount of energy to prepare and presents challenges in storage and transportation. However, many byproducts are still generated during actual production. For example, in the spray forming process, oversprayed powder generated when molten metal droplets miss the solidification of the substrate after cooling becomes an unavoidable powder byproduct. Although the quantity produced in a single production run is small, the cumulative amount over long-term large-scale production is considerable. These powder byproducts not only increase costs but also pose safety hazards. Therefore, the conversion, recycling, and rational utilization of powder byproducts can generate significant economic and environmental benefits. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a powder-forged SiC-reinforced heterogeneous aluminum matrix composite material and its preparation method. This method mixes SiC-aluminum alloy powders of different mass fractions with powder by-products of the same composition, and obtains a SiC-reinforced aluminum matrix composite material with a heterogeneous structure through sintering and powder forging. This achieves efficient utilization of powder by-products and is expected to retain or improve the plasticity of the composite material while improving its strength, thus achieving a high strength-plasticity match for aluminum matrix composite materials.

[0004] This invention is achieved through the following technical solution:

[0005] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0006] Step 1: Mix SiC particles and aluminum alloy powder at a mass ratio of 1:(19-99) to obtain a SiC-aluminum alloy powder mixture;

[0007] Step 2: Mix the SiC-aluminum alloy powder mixture with the aluminum alloy powder by-product at a mass ratio of 1:(0.33-3) to obtain the mixed powder of aluminum-based composite material.

[0008] Step 3: Sinter the mixed powder of aluminum matrix composite material under an inert atmosphere to obtain sintered SiC reinforced aluminum matrix composite material;

[0009] Step 4: Forge the sintered SiC-reinforced aluminum matrix composite material to obtain a SiC-reinforced heterostructure aluminum matrix composite material.

[0010] Preferably, in step 3, the mixed powder of aluminum-based composite material is first pressed into a green blank, and then the green blank is sintered.

[0011] Preferably, the pressing pressure of the green blank is 140-210 MPa.

[0012] Preferably, the sintering temperature in step 3 is 566-600℃; the sintering time is 60-90min.

[0013] Preferably, the forging method in step 4 is as follows:

[0014] The sintered SiC reinforced composite material was held at 475-510℃ for 15-60 min and then subjected to closed-die forging.

[0015] Preferably, the aluminum alloy powder is a mixture of elemental powder and pre-alloyed powder.

[0016] Preferably, the aluminum alloy powder is a mixture of Al, Sn, Al-50Zn, Al-50Mg, Al-50Cu and Al-50Si.

[0017] Preferably, the aluminum alloy powder and the aluminum alloy powder by-product have the same composition.

[0018] Preferably, the aluminum alloy powder has a particle size of 2-30 μm, the SiC particles have a particle size of 5-10 μm, and the aluminum alloy powder by-products have a particle size of 10-140 μm.

[0019] A SiC-reinforced heterostructure aluminum matrix composite material is disclosed. The heterostructure includes three sizes of microstructures: coarse Al grains formed from aluminum alloy powder by-products, fine Al grains formed from aluminum alloy powder, and SiC particles. The coarse Al grains formed from aluminum alloy powder by-products are stabilized by the fine Al grains formed from aluminum alloy powder, and both the coarse and fine grain regions are stabilized by the SiC particles distributed within them.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] This invention provides a method for preparing SiC-reinforced heterogeneous aluminum matrix composites by powder forging. The method involves mixing small-particle-size aluminum alloy powder and aluminum alloy powder byproducts with larger particle sizes of the same composition with SiC particles in a predetermined ratio to form a mixed powder of the aluminum matrix composite. This mixed powder is then pressed into a green blank under a certain pressure, followed by sintering. Finally, the sintered aluminum matrix composite is forged. By controlling the composition, SiC-reinforced aluminum matrix composites with different heterogeneous structural characteristics are obtained. This method rationally utilizes aluminum alloy powder byproducts, reducing the production cost of SiC-reinforced aluminum matrix composites while improving the utilization rate of powder byproducts. Furthermore, the prepared SiC-reinforced aluminum matrix composites form a heterogeneous structure, maintaining or improving the plasticity of the composite while enhancing its strength, achieving a high-strength and plasticity balance in the aluminum matrix composite. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope image of SiC-aluminum alloy mixed powder and aluminum alloy powder byproducts from Example 1 of the present invention;

[0023] (a) is a SiC-aluminum alloy mixed powder, and (b) is an aluminum alloy powder byproduct.

[0024] Figure 2 This is a microstructure diagram of the powder-forged SiC-reinforced heterostructure 7075 aluminum-based composite material of Example 1 of the present invention;

[0025] (a) is the optical metallographic structure, (b) is the scanning electron microscopy metallographic structure, and (c) is the grain distribution;

[0026] Figure 3 The stress-strain curve of the powder-forged SiC-reinforced heterostructure 7075 aluminum matrix composite material in Example 1 of the present invention is shown. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0028] By definition, aluminum alloy powder byproducts refer to incidental powder products that cannot be effectively utilized during the powder metallurgy forming process and instead become the main product. These incidental powder products have a larger particle size than conventional aluminum alloy powders, but their composition is the same. Due to their larger particle size, these incidental products have poor forming and sintering properties and cannot be used directly.

[0029] A powder-forged SiC-reinforced heterogeneous aluminum matrix composite material is formed by pressing, sintering, and forging a mixture of aluminum alloy powder, SiC particles, and aluminum alloy powder by-products. The microstructure of this aluminum matrix composite material is heterogeneous, which includes three sizes of microstructures: coarse Al grains formed by aluminum alloy powder by-products, fine Al grains formed by aluminum alloy powder, and SiC particles. The coarse Al grains formed by aluminum alloy powder by-products are stabilized by the fine Al grains formed by aluminum alloy powder, and both the coarse and fine grain regions are stabilized by the SiC particles distributed within them.

[0030] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0031] Step 1: Prepare aluminum alloy powder.

[0032] The aluminum alloy powder is a mixture of elemental powder and pre-alloyed powder. The elemental powder includes Al powder and Sn powder, and the pre-alloyed powder includes Al-50Zn powder, Al-50Mg powder, Al-50Si powder and Al-50Cu powder. The purity of the above elemental powder and pre-alloyed powder is greater than 99.5%.

[0033] The particle size of Al powder is 20-35 μm, that of Sn powder is 38 μm, that of Al-50Zn powder is 30 μm, that of Al-50Cu powder is 20 μm, that of Al-50Mg powder is 20 μm, and that of Al-50Si powder is 48 μm.

[0034] Aluminum alloy powders include 2-series, 6-series, and 7-series.

[0035] Step 2: Prepare SiC-aluminum alloy powder mixture.

[0036] SiC and aluminum alloy powders are mixed by mass percentage to obtain a SiC-aluminum alloy powder mixture, wherein the ratio of SiC to aluminum alloy powder is 1:(19-99).

[0037] Step 3: Prepare the mixed powder of aluminum-based composite material.

[0038] The SiC-aluminum alloy powder mixture and the aluminum alloy powder by-products are mixed by mass percentage to obtain a mixed powder of aluminum-based composite material. The ratio of SiC-aluminum alloy powder mixture to aluminum alloy powder by-products is 1:(0.33-3).

[0039] The aluminum alloy powder and the aluminum alloy powder by-product have the same composition. The particle size of the aluminum alloy powder is 2-30 μm, the particle size of the SiC particles is 5-10 μm, and the particle size of the aluminum alloy powder by-product is 10-140 μm.

[0040] The purity of the elemental powder, pre-alloyed powder, and aluminum alloy powder by-products is 99.5%.

[0041] Step 4: Sinter the mixed powder of aluminum matrix composite material under an inert atmosphere to obtain sintered SiC reinforced aluminum matrix composite material.

[0042] First, the mixed powder of aluminum-based composite material is pressed into a green blank in a mold, and then the green blank is sintered under N2 atmosphere to obtain sintered SiC reinforced aluminum-based composite material.

[0043] The pressing pressure of the green body is 140-210 MPa; the sintering temperature is 566-600℃; and the sintering time is 60-90 min.

[0044] Step 5: Forge the sintered SiC-reinforced aluminum matrix composite material to obtain a SiC-reinforced heterostructure aluminum matrix composite material.

[0045] First, the sintered SiC reinforced composite material is held at 475-510℃ for 15-60 min, and then closed-die forging is performed to obtain an aluminum-based composite material with a heterogeneous structure. This heterogeneous structure includes three sizes of microstructure: coarse Al grains formed by aluminum alloy powder by-products, fine Al grains formed by aluminum alloy powder, and SiC particles. The coarse Al grains formed by aluminum alloy powder by-products are surrounded by fine Al grains formed by aluminum alloy powder, and both the coarse and fine grain regions are stabilized by SiC particles distributed within them.

[0046] Example 1

[0047] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0048] Step 1: First, prepare 7075 aluminum alloy powder by mixing 80.2% Al powder, 11.3% Al-50Zn powder, 5.2% Al-50Mg powder, 3.1% Al-50Cu powder and 0.2% Sn powder evenly to form 7075 aluminum alloy powder by mass percentage.

[0049] Then, 7075 aluminum alloy powder and SiC particles were mixed at a mass ratio of 97:3 to obtain SiC-7075 aluminum alloy mixed powder.

[0050] Step 2: Mix the 7075 aluminum alloy powder by-product with the SiC-7075 aluminum alloy mixed powder at a mass ratio of 1:1 to obtain the mixed powder of aluminum-based composite material.

[0051] Step 3: Press the mixed powder of aluminum matrix composite material into a green blank at 192 MPa, and then sinter it at 576 °C for 60 min under N2 atmosphere to obtain sintered SiC reinforced 7075 aluminum matrix composite material.

[0052] Step 4: Hold the sintered SiC-reinforced 7075 aluminum matrix composite material at 510℃ for 30 minutes, and then perform closed-die forging to obtain the forged SiC-reinforced 7075 aluminum matrix composite material.

[0053] Figure 2 (a) and (b) show the microstructure and grain distribution of the composite material, respectively. This forged SiC-reinforced 7075 aluminum matrix composite material exhibits a heterogeneous structure comprising three sizes: coarse Al grains formed from 7075 aluminum alloy powder byproducts, fine Al grains formed from 7075 aluminum alloy powder, and SiC particles. The coarse-grained region of the 7075 powder byproducts is surrounded by the 7075 alloy powder region and SiC particles, with both the coarse and fine grain regions stabilized by the distributed SiC particles. The average grain size of the 7075 aluminum alloy powder byproduct region is 50.44 ± 18.74 μm, and the average grain size of the 7075 aluminum alloy powder region is 9.11 ± 2.77 μm. Mechanical properties of the composite material were tested according to GB / T228.1-2021, and the engineering stress-strain curves are shown below. Figure 2 As shown, its yield strength is 301 MPa, tensile strength is 403 MPa, and elongation after fracture is 4.5%.

[0054] Example 2

[0055] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0056] Step 1: First, prepare 7075 aluminum alloy powder. Mix 80.8% Al powder, 11% Al-50Zn powder, 5% Al-50Mg powder, 3% Al-50Cu powder and 0.2% Sn powder evenly to form 7075 aluminum alloy powder by mass percentage.

[0057] Then, 7075 aluminum alloy powder and SiC particles were mixed at a mass ratio of 95:5 to obtain SiC-7075 aluminum alloy mixed powder.

[0058] Step 2: Mix the 7075 aluminum alloy powder by-product with the SiC-7075 aluminum alloy mixed powder at a mass ratio of 3:1 to obtain the mixed powder of aluminum-based composite material.

[0059] Step 3: Press the mixed powder of aluminum matrix composite material into a green blank at 140 MPa, and then sinter it at 600℃ for 60 min under N2 atmosphere to obtain sintered SiC reinforced 7075 aluminum matrix composite material.

[0060] Step 4: Hold the sintered SiC-reinforced 7075 aluminum matrix composite material at 510℃ for 60 min, and then perform closed-die forging to obtain the forged SiC-reinforced heterostructure 7075 aluminum matrix composite material.

[0061] Example 3

[0062] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0063] Step 1: First, prepare 6061 aluminum alloy powder by mixing 96.1% Al powder, 2% Al-50Mg powder, 1.2% Al-50Si powder, 0.5% Al-50Cu powder and 0.2% Sn powder evenly to form 6061 aluminum alloy powder.

[0064] Then, 6061 aluminum alloy powder and SiC particles were mixed at a mass ratio of 99:1 to obtain SiC-6061 aluminum alloy mixed powder.

[0065] Step 2: Mix the 6061 aluminum alloy powder by-product with the SiC-6061 aluminum alloy mixed powder at a mass ratio of 1:3 to obtain the mixed powder of aluminum-based composite material.

[0066] Step 3: Press the mixed powder of aluminum-based composite material into a green blank at 210 MPa, and then sinter it at 566 °C for 75 min under N2 atmosphere to obtain sintered SiC reinforced 6061 aluminum-based composite material.

[0067] Step 4: Hold the sintered SiC-reinforced 6061 aluminum matrix composite material at 475℃ for 15 minutes, and then perform closed-die forging to obtain the forged SiC-reinforced heterostructure 6061 aluminum matrix composite material.

[0068] Example 4

[0069] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0070] Step 1: First, prepare 6061 aluminum alloy powder by mixing 96.1% Al powder, 2% Al-50Mg powder, 1.2% Al-50Si powder, 0.5% Al-50Cu powder and 0.2% Sn powder evenly to form 6061 aluminum alloy powder.

[0071] Then, 6061 aluminum alloy powder and SiC particles were mixed at a mass ratio of 97:3 to obtain SiC-6061 aluminum alloy mixed powder.

[0072] Step 2: Mix the 6061 aluminum alloy powder by-product with the SiC-6061 aluminum alloy mixed powder at a mass ratio of 1:1 to obtain the mixed powder of aluminum-based composite material.

[0073] Step 3: Press the mixed powder of aluminum matrix composite material into a green blank at 210 MPa, and then sinter it at 566 °C for 90 min under N2 atmosphere to obtain sintered SiC reinforced 6061 aluminum matrix composite material.

[0074] Step 4: Hold the sintered SiC-reinforced 6061 aluminum matrix composite material at 475℃ for 30 minutes, and then perform closed-die forging to obtain the forged SiC-reinforced heterostructure 6061 aluminum matrix composite material.

[0075] Example 5

[0076] A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material includes the following steps:

[0077] Step 1: First, prepare 2024 aluminum alloy powder by mixing 87.5% Al powder, 8.8% Al-50Cu powder, 3.2% Al-50Mg powder and 0.5% Sn powder evenly to form 2024 aluminum alloy powder by mass percentage.

[0078] Then, the 2024 aluminum alloy powder and SiC particles were mixed at a mass ratio of 95:5 to obtain SiC-2024 aluminum alloy mixed powder.

[0079] Step 2: Mix the 2024 aluminum alloy powder by-product with the SiC-2024 aluminum alloy mixed powder at a mass ratio of 3:1 to obtain the mixed powder of aluminum-based composite material.

[0080] Step 3: Press the mixed powder of aluminum matrix composite material into a green blank at 192 MPa, and then sinter it at 566 °C for 60 min under N2 atmosphere to obtain sintered SiC reinforced 2024 aluminum matrix composite material.

[0081] Step 4: Hold the sintered SiC-reinforced 2024 aluminum matrix composite material at 500℃ for 60 minutes, and then perform closed-die forging to obtain the forged SiC-reinforced heterostructure 2024 aluminum matrix composite material.

[0082] This invention provides a method for preparing SiC-reinforced heterostructure aluminum matrix composites using powder forging. Fine aluminum alloy powder, larger-particle-size powder byproducts of the same composition, and SiC particles are mixed in different mass ratios. Combining pressing, sintering, and powder forging processes, this method enables the direct design, preparation, and control of SiC-reinforced heterostructure aluminum matrix composites with different characteristics. This invention improves the utilization rate of powder byproducts and reduces production costs. Furthermore, it synergistically enhances the strength and plasticity of SiC-reinforced aluminum matrix composites by forming heterostructures, achieving high-level utilization of powder byproducts and effectively increasing product added value. In addition, this method has advantages such as simple process route, controllable microstructure, and strong applicability to various materials.

[0083] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material, characterized in that, Includes the following steps: Step 1: Mix SiC particles and aluminum alloy powder at a mass ratio of 1:(19~99) to obtain a SiC-aluminum alloy powder mixture; Step 2: Mix the SiC-aluminum alloy powder mixture with the aluminum alloy powder by-product at a mass ratio of 1:(0.33-3) to obtain a mixed powder of aluminum-based composite material. Step 3: Sinter the mixed powder of aluminum matrix composite material under an inert atmosphere to obtain sintered SiC reinforced aluminum matrix composite material; Step 4: Forge the sintered SiC-reinforced aluminum matrix composite material to obtain a SiC-reinforced heterostructure aluminum matrix composite material; The forging method is as follows: The sintered SiC reinforced composite material is held at 475-510℃ for 15-60 min and then subjected to closed-die forging; wherein the aluminum alloy powder and the aluminum alloy powder by-product have the same composition; and the particle size of the aluminum alloy powder is 2-30 μm, the particle size of the SiC particles is 5-10 μm, and the particle size of the aluminum alloy powder by-product is 10-140 μm.

2. The method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material according to claim 1, characterized in that, In step 3, the mixed powder of aluminum-based composite material is first pressed into a green compact, and then the green compact is sintered.

3. The method of claim 2, wherein the powder forging of SiC reinforced heterogeneous structured aluminum matrix composite is characterized by, The pressing pressure of the green body is 140-210 MPa.

4. The method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material according to claim 1, characterized in that, The sintering temperature in step 3 is 566-600 ℃; the sintering time is 60-90 min.

5. The method for preparing a powder-forged SiC-reinforced heterostructure aluminum matrix composite material according to claim 1, characterized in that, The aluminum alloy powder is a mixture of elemental powder and pre-alloyed powder.

6. The method of claim 5, wherein the powder forging of SiC reinforced heterogeneous structured aluminum matrix composite is characterized by, The aluminum alloy powder is a mixture of Al, Sn, Al-50Zn, Al-50Mg, Al-50Cu and Al-50Si.

7. A SiC-reinforced heterostructured aluminium matrix composite produced by the method of any one of claims 1 to 6, characterized in that The aluminum-based composite material has a heterogeneous structure, which includes three sizes of microstructures: coarse Al grains formed from aluminum alloy powder by-products, fine Al grains formed from aluminum alloy powder, and SiC particles. The coarse Al grains formed from aluminum alloy powder by-products are surrounded by fine Al grains formed from aluminum alloy powder, and both the coarse and fine grain regions are stabilized by SiC particles distributed within them.

Images