A method for preparing a harmonic heterostructure aluminum matrix composite

Abstract

The present application belongs to the field of metal composite material, and particularly relates to a preparation method of harmonic heterostructure aluminum-based composite material. The preparation method of the harmonic heterostructure aluminum-based composite material comprises the following steps: mixing two kinds of aluminum powder with different particle sizes with titanium boride and stainless steel balls for ball milling, and separating the stainless steel balls after ball milling to obtain a mixed powder; vacuum hot-pressing sintering the mixed powder, and obtaining the harmonic heterostructure aluminum-based composite material after cooling. The present application designs the harmonic heterostructure aluminum-based composite material which simultaneously has coarse-grained regions and fine-grained regions. The fine-grained regions have higher strength, which is beneficial to improving the strength of the composite material, and the coarse-grained regions have higher damage tolerance, which is beneficial to improving the plasticity. Meanwhile, the difference in mechanical properties between the fine-grained regions and the coarse-grained regions will cause heterostructure deformation, back stress is generated in the coarse-grained regions, and front stress is generated in the fine-grained regions, so that the good plasticity is maintained while the heterostructure deformation induced strengthening is generated, and the harmonic heterostructure aluminum-based composite material has good comprehensive mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of metal composite materials, and specifically relates to a method for preparing a harmonic heterostructure aluminum-based composite material. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Introducing ceramic particles such as Si3N4, SiC, B4C, and TiB2 into an aluminum matrix can significantly improve the mechanical properties of the matrix alloy. However, because hard, rigid phases easily induce strain concentration, the reinforcing particles, while improving material strength, also lead to a severe decrease in plasticity. Furthermore, there is an inverse relationship between strength and plasticity in traditional homogeneous materials; that is, increasing material strength comes at the cost of sacrificing plasticity, making it impossible to simultaneously achieve high strength and high plasticity. By organically combining different microstructures to form heterogeneous structures, this inverse relationship between material strength and plasticity can be overcome, achieving a synergistic improvement in both.

[0004] Currently, heterogeneous materials can be prepared using methods such as additive manufacturing, cumulative rolling, cold rolling and heat treatment, and hot pressing sintering. Invention CN115815622A discloses a method for manufacturing heterogeneous metallic materials using friction stir assisted laser additive manufacturing. This method employs a combination of laser additive manufacturing and friction stir processing, first adding material to a substrate and then performing localized friction stir processing, repeating this process to complete the additive manufacturing of the heterogeneous structure. The advantage of this invention is that it can simultaneously improve the strength and toughness of the metallic material; the disadvantage is that the proportion of each heterogeneous component within the material is difficult to control precisely. Invention CN113403517A discloses a method for preparing a heterogeneous Al2O3 / CrCoNi nanocomposite material. This method obtains CrCoNi powders with different grain sizes through different ball milling conditions, and finally obtains the heterogeneous Al2O3 / CrCoNi nanocomposite material by vacuum hot pressing sintering. This invention achieves a synergistic improvement in the strength and plasticity of the composite material through the combination of coarse-grained and fine-grained regions; however, the preparation cycle is long, with the longest ball milling time reaching 55 hours, making it difficult to achieve high-efficiency mass production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a harmonic heterostructure aluminum matrix composite material. This invention designs a harmonic heterostructure aluminum matrix composite material possessing both coarse-grained and fine-grained regions. The fine-grained region exhibits higher strength, which is beneficial for improving the composite material's overall strength, while the coarse-grained region has higher damage tolerance, which is beneficial for improving plasticity. Simultaneously, the difference in mechanical properties between the fine-grained and coarse-grained regions will induce heterogeneous deformation. To maintain coordinated deformation between grains, geometrically necessary dislocations need to be introduced and stored at the coarse-grained / fine-grained region boundary. This will generate back stress in the coarse-grained region and forward stress in the fine-grained region, thereby achieving heterogeneous deformation-induced strengthening while maintaining good plasticity, resulting in a harmonic heterostructure aluminum matrix composite material with excellent comprehensive mechanical properties.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a method for preparing a harmonic heterostructure aluminum-based composite material, characterized by comprising the following steps: S1. Two types of aluminum powder with different particle sizes are mixed with titanium boride and stainless steel balls and ball-milled. After ball milling, the stainless steel balls are separated to obtain mixed powder. S2. The mixed powder is subjected to vacuum hot pressing sintering, and after cooling, a harmonic heterostructure aluminum matrix composite material is obtained.

[0007] Preferably, the aluminum powder includes 6061 aluminum powder, the ratio of the two different particle sizes is (9~11):1, and the mass ratio of the two aluminum powders with different particle sizes is 1:(0.9~1.1).

[0008] Preferably, the mass ratio of the titanium boride to the aluminum powder is 1:(11~12).

[0009] More preferably, the particle size ratio of the titanium boride to the smaller aluminum powder in the aluminum powder is (1~1.1):1.

[0010] Preferably, the stainless steel balls are composed of stainless steel balls of 5 mm, 8 mm and 10 mm in a mass ratio of 5:3:2.

[0011] Preferably, the mass ratio of the stainless steel ball to the total mass of aluminum powder and titanium boride is (4~6):1.

[0012] Preferably, the ball mill rotation speed is 200~400 r / min, the ball milling time is 1.5~2.5 h, and the ball milling program is set to alternate between 30 min forward rotation and 30 min reverse rotation, with a 10 min pause after every 30 min of ball milling.

[0013] Preferably, the stainless steel balls are separated by passing them through a 100-mesh sieve after ball milling.

[0014] Preferably, during vacuum hot pressing sintering, the pressure is below 1 × 10⁻⁶. -2 Sintering begins at a pressure of 29-31 MPa. The temperature is first increased to 195-205 °C at a rate of 9-11 °C / min and held for 25-35 min. Then, the temperature is increased to 550-570 °C at a rate of 9-11 °C / min and the pressure is increased to 29-31 MPa. The temperature is held for 55-65 min.

[0015] In a second aspect, the present invention provides a harmonic heterostructure aluminum-based composite material, which is obtained by the preparation method described in the first aspect.

[0016] The beneficial effects achieved by one or more technical solutions of the present invention are as follows: (1) Compared with traditional uniform aluminum matrix composites, the TiB2 / 6061Al composite material designed in this invention has a harmonic structure in which a fine-grained region surrounds a coarse-grained region. This structure realizes the organic combination of the fine-grained region and the coarse-grained region, which is beneficial to the realization of heterogeneous deformation-induced strengthening.

[0017] (2) Compared with traditional methods for preparing heterostructure materials, this invention has advantages such as simple process and easy control of coarse and fine crystal ratio. Moreover, it can be carried out on traditional equipment without the need to modify the preparation equipment, and can achieve high-quality, high-efficiency and low-cost preparation of harmonic heterostructure aluminum matrix composite materials.

[0018] (3) By mixing coarse and fine 6061Al powder, the present invention not only realizes the construction of harmonic heterostructure, but also overcomes the disadvantage of poor sintering performance of fine aluminum powder. The resulting harmonic heterostructure aluminum matrix composite material has higher density.

[0019] (4) The preparation process designed in this invention is very flexible. It can not only optimize the heterostructure by changing the particle size of 6061Al powder, but also be applied to the preparation of Mg-based, Cu-based and Ti-based harmonic heterostructure composite materials.

[0020] (5) Compared with uniform fine-grained and uniform coarse-grained composite materials, the TiB2 / 6061Al composite material with harmonic heterostructure designed in this invention has higher density, higher strength and higher plasticity, achieving a synergistic improvement in strength and plasticity. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 This is a flowchart illustrating the preparation process of the harmonic heterostructure aluminum-based composite material in Example 1 of the present invention. Figure 2 Microscopic image of the harmonic heterostructure TiB2 / 6061Al composite material prepared in Example 1 of this invention; Figure 3 This is a microstructure photograph of the uniform coarse-grained TiB2 / 6061Al composite material prepared in Comparative Example 1 of this invention. Figure 4 This is a microstructure photograph of the uniform fine-grained TiB2 / 6061Al composite material prepared in Comparative Example 2 of this invention. Figure 5 The mechanical properties of TiB2 / 6061Al composite materials with different structures are shown in the figure. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0024] Example 1 like Figure 1 As shown, the preparation method of the harmonic heterostructure TiB2 / 6061Al composite material is as follows: (1) Weigh 1500 g of stainless steel balls and put them into the ball mill jar, wherein the ratio of 5 mm, 8 mm and 10 mm stainless steel balls is 5:3:2.

[0025] (2) Weigh 300 g of 6061Al (Al-1.05Mg-0.53Si-0.28Cu-0.03Cr-0.26Fe) powder and TiB2 particles and put them into a ball mill jar. The proportions of coarse 6061Al powder, fine 6061Al powder and TiB2 particles are 46 wt.% (47.5 vol.%), 46 wt.% (47.5 vol.%) and 8 wt.% (5 vol.%), respectively. The ratio of stainless steel balls to mixed powder is 5:1. The average particle sizes of coarse 6061Al powder, fine 6061Al powder and TiB2 particles are 16.05, 1.56 and 1.69 μm, respectively.

[0026] (3) Seal the ball mill jar containing stainless steel balls and mixed powder, and use a vacuum pump to perform vacuum treatment.

[0027] (4) Transfer the ball mill jar configured in step (3) to a planetary ball mill for ball milling. The ball milling speed is set to 300 r / min, the ball milling time is 2 h, and the ball milling program is set to alternate between forward rotation for 30 min and reverse rotation for 30 min, with a 10 min stop after each 30 min of ball milling.

[0028] (5) Pass the powder after ball milling in step (4) through a 100-mesh sieve to separate the stainless steel balls and the mixed powder.

[0029] (6) Load the mixed powder from step (5) into a graphite mold and transfer it to a vacuum hot pressing sintering furnace.

[0030] (7) Vacuum the vacuum hot pressing sintering furnace until the gas pressure inside the furnace is lower than 1 × 10⁻⁶. -2 Sintering begins at a pressure of 30 MPa. During sintering, the temperature is first increased to 200 °C at a rate of 10 °C / min, and then held at 200 °C for 30 min to remove gas from the mixed powder. Then, the temperature is increased to 560 °C at a rate of 10 °C / min, while the sintering pressure is increased to 30 MPa. Finally, the sintering is completed after holding at 560 °C for 60 min.

[0031] (8) After sintering, the sample is left in the sintering furnace for furnace cooling. Once the temperature drops below 100 ℃, the vacuum is released and the sample is removed. The sintered material is the TiB2 / 6061Al composite material with a harmonic heterostructure. Figure 2 As shown, in the harmonic heterostructure TiB2 / 6061Al composite material, the fine-grained region surrounds the coarse-grained region to form a harmonic structure.

[0032] Comparative Example 1 Preparation method of uniform coarse-grained TiB2 / 6061Al composite material: (1) Weigh 1500 g of stainless steel balls and put them into the ball mill jar, wherein the ratio of 5 mm, 8 mm and 10 mm stainless steel balls is 5:3:2.

[0033] (2) Weigh 300 g of 6061Al (Al-1.05Mg-0.53Si-0.28Cu-0.03Cr-0.26Fe) powder and TiB2 particles and put them into a ball mill jar. The proportions of 6061Al powder and TiB2 particles are 92wt.% (95 vol.%) and 8wt.% (5 vol.%), respectively. The ratio of stainless steel balls to mixed powder is 5:1. The average particle sizes of 6061Al powder and TiB2 particles are 16.05 and 1.69 μm, respectively.

[0034] (3) Seal the ball mill jar containing stainless steel balls and mixed powder, and use a vacuum pump to perform vacuum treatment.

[0035] (4) Transfer the ball mill jar configured in step (3) to a planetary ball mill for ball milling. The ball milling speed is set to 300 r / min, the ball milling time is 2 h, and the ball milling program is set to alternate between forward rotation for 30 min and reverse rotation for 30 min, with a 10 min stop after each 30 min of ball milling.

[0036] (5) Pass the powder after ball milling in step (4) through a 100-mesh sieve to separate the stainless steel balls and the mixed powder.

[0037] (6) Load the mixed powder from step (5) into a graphite mold and transfer it to a vacuum hot pressing sintering furnace.

[0038] (7) Vacuum the vacuum hot pressing sintering furnace until the gas pressure inside the furnace is lower than 1 × 10⁻⁶. -2 Sintering begins at a pressure of 30 MPa. During sintering, the temperature is first increased to 200 °C at a rate of 10 °C / min, and then held at 200 °C for 30 min to remove gas from the mixed powder. Then, the temperature is increased to 560 °C at a rate of 10 °C / min, while the sintering pressure is increased to 30 MPa. Finally, the sintering is completed after holding at 560 °C for 60 min.

[0039] (8) After sintering, the sample is left in the sintering furnace for furnace cooling. Once the temperature drops below 100 °C, the vacuum is released and the sample is removed. The sintered material is a TiB2 / 6061Al composite material with a uniform coarse-grained structure. Figure 3 As shown, the composite material only has a coarse-grained region.

[0040] Comparative Example 2 Preparation method of uniform fine-grained TiB2 / 6061Al composite material: (1) Weigh 1500 g of stainless steel balls and put them into the ball mill jar, wherein the ratio of 5 mm, 8 mm and 10 mm stainless steel balls is 5:3:2.

[0041] (2) Weigh 300 g of 6061Al (Al-1.05Mg-0.53Si-0.28Cu-0.03Cr-0.26Fe) powder and TiB2 particles and put them into a ball mill jar. The proportions of 6061Al powder and TiB2 particles are 92wt.% (95 vol.%) and 8wt.% (5 vol.%), respectively. The ratio of stainless steel balls to mixed powder is 5:1. The average particle sizes of 6061Al powder and TiB2 particles are 1.56 and 1.69 μm, respectively.

[0042] (3) Seal the ball mill jar containing stainless steel balls and mixed powder, and use a vacuum pump to perform vacuum treatment.

[0043] (4) Transfer the ball mill jar configured in step (3) to a planetary ball mill for ball milling. The ball milling speed is set to 300 r / min, the ball milling time is 2 h, and the ball milling program is set to alternate between forward rotation for 30 min and reverse rotation for 30 min, with a 10 min stop after each 30 min of ball milling.

[0044] (5) Pass the powder after ball milling in step (4) through a 100-mesh sieve to separate the stainless steel balls and the mixed powder.

[0045] (6) Load the mixed powder from step (5) into a graphite mold and transfer it to a vacuum hot pressing sintering furnace.

[0046] (7) Vacuum the vacuum hot pressing sintering furnace until the gas pressure inside the furnace is lower than 1 × 10⁻⁶. -2 Sintering begins at a pressure of 30 MPa. During sintering, the temperature is first increased to 200 °C at a rate of 10 °C / min, and then held at 200 °C for 30 min to remove gas from the mixed powder. Then, the temperature is increased to 560 °C at a rate of 10 °C / min, while the sintering pressure is increased to 30 MPa. Finally, the sintering is completed after holding at 560 °C for 60 min.

[0047] (8) After sintering, the sample is left in the sintering furnace for furnace cooling. Once the temperature drops below 100 °C, the vacuum is released and the sample is removed. The sintered material is a TiB2 / 6061Al composite material with a uniform coarse-grained structure. Figure 4 As shown, the composite material only has a fine-grained region.

[0048] The density of the three TiB2 / 6061Al composite materials obtained in Example 1 and Comparative Examples 1 and 2 is shown in Table 1. The harmonic heterostructure gives the TiB2 / 6061Al composite material a higher density.

[0049] like Figure 5 As shown, the harmonic heterostructure gives the TiB2 / 6061Al composite material higher strength and elongation after fracture. During tensile testing, the harmonic heterostructure induces heterogeneous deformation. To maintain coordinated deformation between grains, a large number of geometrically necessary dislocations are introduced and stored at the coarse-grained / fine-grained region boundary. This generates back stress in the coarse-grained region and forward stress in the fine-grained region, thus jointly forming heterogeneous deformation-induced strengthening and achieving a synergistic improvement in strength and plasticity.

[0050] Table 1 Density of TiB2 / 6061Al composites with different structures

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a harmonic heterostructure aluminum-based composite material, characterized in that, Includes the following steps: S1. Two types of aluminum powder with different particle sizes are mixed with titanium boride and stainless steel balls and ball-milled. After ball milling, the stainless steel balls are separated to obtain mixed powder. S2. The mixed powder is vacuum hot-pressed and sintered, and then cooled to obtain a harmonic heterostructure aluminum matrix composite material. The aluminum powder includes 6061 aluminum powder, the ratio of the two different particle sizes is (9~11):1, and the mass ratio of the two aluminum powders with different particle sizes is 1:

1. The mass ratio of titanium boride to aluminum powder is 1:(11~12); The particle size ratio of the titanium boride to the smaller aluminum powder in the aluminum powder is (1~1.1):1; The stainless steel balls are composed of 5 mm, 8 mm and 10 mm stainless steel balls in a mass ratio of 5:3:2; The composite material has a harmonic structure in which a fine-grained region surrounds a coarse-grained region.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the stainless steel ball to the total mass of aluminum powder and titanium boride is (4~6):

1.

3. The preparation method according to claim 1, characterized in that, The ball mill speed is 200~400 r / min, the ball milling time is 1.5~2.5 h, and the ball milling program is set to alternate between 30 min forward rotation and 30 min reverse rotation, with a 10 min pause after every 30 min of ball milling.

4. The preparation method according to claim 1, characterized in that, After ball milling, the stainless steel balls are separated by passing them through a 100-mesh sieve.

5. The preparation method according to claim 1, characterized in that, During vacuum hot pressing sintering, the pressure is below 1 × 10⁻⁶. -2 Sintering begins at a pressure of 29-31 MPa. The temperature is first increased to 195-205 ℃ at a rate of 9-11 ℃ / min and held for 25-35 min. Then, the temperature is increased to 550-570 ℃ at a rate of 9-11 ℃ / min and the pressure is increased to 29-31 MPa. The temperature is held for 55-65 min.

6. A harmonic heterostructure aluminum-based composite material, characterized in that, Obtained by the preparation method described in any one of claims 1-5.

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