A method for powder forging of an aluminum matrix composite

Abstract

The application discloses a kind of aluminum matrix composite powder die forging preparation methods, specifically related to metal matrix composite preparation and forming processing field.The method includes: aluminum powder, alloying element powder and ceramic reinforcing particles are made into near-spherical composite particles with particle size 0.15mm~3mm by mechanical ball milling;Composite particles are loaded into mold cavity, heated to 250℃~650℃ in protective atmosphere and applied not less than 20MPa die forging pressure, directly formed into die forging;Finally, after deburring and size finishing, the part is obtained.Ceramic reinforcing particles volume fraction is 1%~35%, and aluminum powder and alloying element powder particle size is 10μm~50μm.The application organically combines ball milling mixing and die forming, realizes powder densification and part forming one-step completion, simplifies traditional multi-process process flow, significantly improves production efficiency and material utilization, reduces production cost, and is suitable for batch manufacturing of high-performance aluminum matrix composite parts.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite material preparation and forming, specifically to a method for preparing aluminum matrix composite materials by powder forging. This method is suitable for the mass production of high-performance aluminum matrix composite parts reinforced with ceramic particles. Background Technology

[0002] Aluminum-based composite materials, by introducing reinforcing phases such as ceramic particles, short fibers, or whiskers into aluminum alloys, can effectively improve the elastic modulus, strength, and wear resistance of the materials while maintaining a low density. They have broad application prospects in aerospace, rail transportation, and high-end equipment manufacturing. With the rapid development of the new energy vehicle industry and the increasingly urgent need for lightweighting, the demand for aluminum-based composite materials to replace traditional steel or heavy alloy materials in high-volume, low-cost production scenarios is becoming increasingly prominent.

[0003] Currently, aluminum-based composite materials are mostly prepared using powder metallurgy, with a typical process including powder mixing or ball milling, vacuum hot pressing sintering to prepare billets, plastic deformation processes such as extrusion or die forging, and subsequent extensive machining finishing. However, the above process has significant shortcomings: firstly, the vacuum hot pressing sintering equipment has a limited capacity, typically producing only a single specification of billet at a time, resulting in low production efficiency; secondly, the sintered billet requires multiple plastic deformation and machining processes to obtain the final part shape, leading to a long production process, large equipment investment, significant material waste, and high overall manufacturing costs. Therefore, how to simplify the process, improve material utilization, and reduce production costs while ensuring material performance has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing aluminum-based composite powder by die forging. By organically combining mechanical ball milling with high-temperature die forging in a mold, aluminum-based composite material components with near-final shapes are directly obtained while achieving rapid densification and metallurgical bonding of powder particles. This reduces processes, improves production efficiency, and lowers manufacturing costs.

[0005] The basic idea of ​​this invention is as follows: First, aluminum powder, necessary alloying element powder, and ceramic reinforcing particles are thoroughly mixed at the microscale using ball milling and subjected to a certain degree of mechanical alloying. This allows the ceramic particles to be uniformly embedded in the metal powder, forming mixed elementary particles with a particle size ranging from sub-millimeter to millimeter. Subsequently, these mixed elementary particles are filled into a mold cavity with the outline of the part. Under the combined action of high temperature and external pressure, the particles undergo synergistic plastic flow and diffusion bonding, completing densification and shaping in one step. This yields a composite material forging with a dense structure, uniform microstructure, and near-final dimensions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing aluminum-based composite material by powder forging includes the following steps: (1) Aluminum powder, alloy element powder and ceramic reinforcing particles are fed into a ball mill and near-spherical composite particles with a particle size of 0.15 mm to 3 mm are obtained by mechanical ball milling; (2) The composite particles obtained in step (1) are loaded into the mold cavity and segmented forging is carried out under a protective atmosphere: first, a first pressure is applied in the temperature range of 250℃~400℃, and then a second pressure is applied in the temperature range of 450℃~650℃. The first pressure and the second pressure are both not less than 20MPa, and aluminum-based composite material forgings are obtained. (3) The die forging is deburred and dimensionally trimmed to obtain aluminum-based composite material parts.

[0007] Furthermore, the ceramic reinforcing particles account for 1% to 35% of the total volume of the powder.

[0008] Furthermore, the ceramic reinforcing particles are one or a combination of two or more of silicon carbide, boron carbide, titanium carbide, titanium diboride, and alumina.

[0009] Furthermore, the particle size range of the aluminum powder and alloy element powder is 10μm to 50μm.

[0010] Furthermore, the alloying elements include one or more of zinc, copper, magnesium, silicon, and iron.

[0011] Furthermore, in step (1), aluminum alloy pre-alloyed powder is used as raw material.

[0012] Furthermore, in step (1), the ball milling is carried out using a planetary or drum ball mill, with a ball-to-material ratio of 1:1 to 15:1 and a ball milling time of no more than 1 hour.

[0013] Furthermore, the mold in step (2) is made of graphite, ceramic or mold steel.

[0014] Furthermore, step (2) is carried out under a nitrogen protective atmosphere, and the mold is preheated to 250℃~650℃.

[0015] Furthermore, the first pressure is 50 MPa to 150 MPa, the second pressure is 20 MPa to 100 MPa, and the pressure holding time within the temperature range of 450℃ to 650℃ is 5 minutes to 30 minutes.

[0016] Beneficial effects of this invention: 1. By combining mechanical ball milling with high-temperature die forging in a mold, the multi-step process of "vacuum sintering billet preparation + subsequent hot extrusion / die forging" in the traditional process is integrated into one step, which simplifies the process, reduces the configuration requirements of special sintering and plastic deformation equipment, effectively shortens the production cycle, and reduces equipment investment and production costs.

[0017] 2. The ball milling process not only achieves uniform distribution of ceramic reinforcing particles in the aluminum matrix, but also breaks the oxide film on the surface of the aluminum powder through mechanical action, promotes the diffusion of alloying elements, and creates favorable conditions for the metallurgical bonding between powder particles in the subsequent die forging process, which helps to improve the density and mechanical properties of the final material.

[0018] 3. Sub-millimeter to millimeter-sized near-spherical composite particles obtained after ball milling are used as forging raw materials. These particles have good fluidity and low deformation resistance at high temperatures, which can better fill the mold cavity, thereby forming a forging that is close to the final contour of the part in one forging process. This significantly improves material utilization and reduces subsequent machining allowance and tool wear.

[0019] 4. By applying temperature and pressure in stages during the die forging process, the plastic deformation and diffusion bonding process of composite particles can be better controlled, which helps to avoid the generation of material defects and further improves the forming quality and performance consistency of die forgings. Attached Figure Description

[0020] Figure 1 This is a process flow diagram for the preparation of an aluminum-based composite material by powder forging. Detailed Implementation

[0021] The preparation method of the present invention will be described in detail below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0022] Example 1 This embodiment prepares an aluminum-based composite ring part reinforced with 10% SiC particles by volume. The process flow diagram for the aluminum-based composite powder forging preparation is shown below. Figure 1 The specific steps are as follows: (1) Raw material preparation and ball milling: SiC particles with an average particle size of 7 μm were selected as the ceramic reinforcing phase, and aluminum powder with a particle size of 13 μm was used as the matrix, with copper and magnesium powder added as alloying elements. The raw materials, by volume fraction, were: 10% SiC particles, with the balance being aluminum matrix (containing 1.8% Cu and 1.4% Mg). The powder was fed into a planetary ball mill, with a ball-to-powder ratio of 5:1 and a milling time of 45 minutes, to obtain near-spherical composite particles with a particle size of 2 mm.

[0023] (2) Die filling and powder forging: The composite particles obtained in step (1) are filled into a cup-shaped mold cavity made of graphite material, and the cavity shape is consistent with the contour of the target annular part. The filled mold is placed in a hot press, and under a nitrogen protective atmosphere, the mold is first preheated to 350°C and a first pressure of 100 MPa is applied; then the temperature is further increased to 550°C and a second pressure of 100 MPa is applied, and the pressure is held for 10 minutes. After cooling, the mold is demolded to obtain a cup-shaped aluminum-based composite material forging.

[0024] (3) Post-processing: The die forgings are deburred and machined to achieve necessary dimensional adjustments, resulting in ring-shaped parts that closely resemble their final shape.

[0025] Example 2 This embodiment prepares a triangular part made of aluminum matrix composite material reinforced with 17 vol.% SiC particles. The specific steps are as follows: (1) Raw material preparation and ball milling: SiC particles with an average particle size of 13 μm were selected as the ceramic reinforcing phase, and the matrix consisted of 2009 aluminum alloy pre-alloyed powder with a particle size of 13 μm. The raw materials, by volume fraction, were: 17% SiC particles and the remainder being 2009 aluminum alloy pre-alloyed powder. The powder was fed into a drum ball mill with a ball-to-powder ratio of 8:1 and a milling time of 30 minutes to obtain near-spherical composite particles with a particle size of 3 mm.

[0026] (2) Die filling and powder forging: The composite particles obtained in step (1) are filled into a triangular mold cavity made of mold steel, the cavity shape of which matches the outline of the target triangular part. The filled mold is placed in a hot press, and under a nitrogen protective atmosphere, the mold is first preheated to 300°C and a first pressure of 150 MPa is applied; then the temperature is further increased to 530°C and a second pressure of 50 MPa is applied, and the pressure is held for 10 minutes. After cooling, the mold is demolded to obtain a triangular aluminum-based composite material forging.

[0027] (3) Post-processing: The die forgings are deburred and machined to achieve necessary dimensional adjustments, resulting in a triangular part that approximates the final shape.

[0028] Matters not covered in this invention are common knowledge.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications, equivalent substitutions, and improvements made by those skilled in the art based on the essence of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing aluminum-based composite material by powder forging, characterized in that, Includes the following steps: (1) Aluminum powder, alloy element powder and ceramic reinforcing particles are fed into a ball mill and near-spherical composite particles with a particle size of 0.15 mm to 3 mm are obtained by mechanical ball milling; (2) The composite particles obtained in step (1) are loaded into the mold cavity and segmented forging is performed under a protective atmosphere: first, a first pressure is applied in the temperature range of 250℃~400℃, and then a second pressure is applied in the temperature range of 450℃~650℃. The first pressure and the second pressure are both not less than 20MPa to obtain aluminum-based composite material forgings; wherein, the process is carried out under a nitrogen protective atmosphere, and the mold is preheated to 250℃~650℃; the first pressure is 50MPa~150MPa, the second pressure is 20MPa~100MPa, and the holding time in the temperature range of 450~650℃ is 5 minutes~30 minutes; (3) The die forging is deburred and dimensionally trimmed to obtain aluminum-based composite material parts.

2. The method for preparing aluminum-based composite materials by powder forging according to claim 1, characterized in that: The ceramic reinforcing particles account for 1% to 35% of the total volume of the powder.

3. The method for preparing aluminum-based composite materials by powder forging according to claim 2, characterized in that: The ceramic reinforcing particles are one or a combination of two or more of silicon carbide, boron carbide, titanium carbide, titanium diboride, and alumina.

4. The method for preparing aluminum-based composite materials by powder forging according to claim 1, characterized in that: The particle size range of the aluminum powder and alloy element powder is 10μm to 50μm.

5. The method for preparing aluminum-based composite material by powder forging according to claim 4, characterized in that: The alloying elements include one or more of zinc, copper, magnesium, silicon, and iron.

6. The method for preparing aluminum-based composite materials by powder forging according to claim 1, characterized in that: In step (1), aluminum alloy pre-alloyed powder is used as raw material.

7. The method for preparing aluminum-based composite materials by powder forging according to claim 1, characterized in that: In step (1), a planetary or drum ball mill is used for ball milling, with a ball-to-material ratio of 1:1 to 15:1 and a milling time of no more than 1 hour.

8. The method for preparing aluminum-based composite material by powder forging according to claim 1, characterized in that: The mold in step (2) is made of graphite, ceramic or mold steel.

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