阅读说明：本技术 一种利用空心微球制备多孔铝合金的方法 (Method for preparing porous aluminum alloy by using hollow microspheres ) 是由 *** 赵心阅 马运柱 刘超 王涛 颜焕元 伍镭 杨伦 于 2020-07-16 设计创作，主要内容包括：本发明涉及一种利用空心微球制备多孔铝合金的方法。其特征包括以下步骤：采用氧化铝(Al<Sub>2</Sub>O<Sub>3</Sub>)空心微球作为造孔剂,于保护气氛下,在手套箱内将氧化铝空心微球与铝合金粉末按照一定的体积比装入密闭容器内,再进行充分混料,得到均匀混合的氧化铝空心微球+铝合金前驱体粉末；采用真空热压烧结,将氧化铝空心微球+铝合金前驱体粉末均匀地放入模具中,控制烧结参数与压力,得到具有一定孔隙率的均匀的球形孔的多孔铝合金。本发明解决了造孔剂难以脱除和孔的大小和形状难以精准控制的问题,制备出的多孔铝合金孔洞分布均匀,孔洞呈球形且孔径为微米级；工艺简单,操作灵活,成本较低。(The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres. The method is characterized by comprising the following steps: using aluminium oxide (Al) 2 O 3 ) The method comprises the following steps of (1) taking hollow microspheres as a pore-forming agent, filling alumina hollow microspheres and aluminum alloy powder into a closed container according to a certain volume ratio in a glove box under a protective atmosphere, and fully mixing to obtain uniformly mixed alumina hollow microspheres and aluminum alloy precursor powder; and (3) adopting vacuum hot-pressing sintering, uniformly putting the alumina hollow microspheres and the aluminum alloy precursor powder into a mould, and controlling sintering parameters and pressure to obtain the uniform spherical-pore porous aluminum alloy with certain porosity. The invention solves the problems that the pore-forming agent is difficult to remove and the size and the shape of the pores are difficult to accurately control, and the prepared porous aluminum alloy has uniform pore distribution, spherical pores and micron-sized pore diameters; simple process, flexible operation and low cost.)

1. A method for preparing porous aluminum alloy by utilizing hollow microspheres is characterized in that; the preparation method comprises the following steps:

a) using aluminium oxide (Al)₂O₃) The method comprises the following steps of (1) taking hollow microspheres as a pore-forming agent, filling alumina hollow microspheres and aluminum alloy powder into a closed container according to a certain volume ratio in a glove box under a protective atmosphere, and fully mixing to obtain uniformly mixed alumina hollow microspheres and aluminum alloy precursor powder;

b) and (3) adopting vacuum hot-pressing sintering, uniformly putting the alumina hollow microspheres and the aluminum alloy precursor powder into a mould, and controlling sintering parameters and pressure to obtain the uniform spherical-pore porous aluminum alloy with certain porosity.

2. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the outer diameter of the alumina hollow microsphere in the step a) is 10-200 μm.

3. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps:

the protective atmosphere in the step a) is one of argon atmosphere and helium atmosphere;

the wall thickness of the alumina hollow microsphere in the step a) is 1-10 μm.

4. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the aluminium alloy powder in step a) is 2a12 or 2024 aluminium alloy powder.

5. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the mixing time in the step a) is 1-10 h.

6. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the bulk density of the alumina hollow spheres in the step a) is 0.1g/cm³-1.5g/cm³。

7. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the volume ratio of the alumina hollow microspheres to the aluminum alloy powder in the step a) is 1:9-9: 1.

8. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the sintering temperature in the step b) is 550-650 ℃, and the heat preservation time is 1-5 h.

9. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the sintering pressure in the step b) is 1MPa-100 MPa.

10. The method for preparing the porous aluminum alloy by using the hollow microspheres according to claim 1, wherein the method comprises the following steps: the porosity of the porous aluminum alloy in step b) is 10% -90%.

Technical Field

The invention relates to a method for preparing porous aluminum alloy by using hollow microspheres, in particular to a method for preparing porous aluminum alloy by using aluminum oxide (Al) with regular shape and certain strength₂O₃) A method for preparing porous aluminum alloy by utilizing vacuum hot-pressing sintering by using hollow microspheres as a pore-forming agent without removing the pore-forming agent belongs to the technical field of metal functional materials.

Background

The porous aluminum alloy has excellent performances such as low density, high specific stiffness, high damping and shock absorption performance, high impact energy absorption rate and the like, and is widely applied to the fields of aerospace, electronics, buildings and the like.

The pore size and pore shape of porous aluminum alloys have a large impact on the structure and properties. The mechanical property of the sintered porous material is reduced along with the increase of porosity and aperture, and is very sensitive to the shape of the pore, namely, the sintered porous material is related to a notch effect, and the spherical pore can effectively reduce stress concentration; the contact area of spherical pores is the largest with uniform pore size, and the absorption of energy by the material is also the largest when the porosity is constant. The small pore diameter can enable the material to achieve higher porosity, the higher the porosity is, the smaller the pore diameter is, the larger the inner surface area of the pore is, the faster the energy is consumed after entering, and the better the energy absorption performance of the porous material is; when the porosity is constant, the material having a small pore diameter has a small permeability, but the material has a large strength due to a large number of interparticle contact points. Therefore, how to achieve spherical pores and micron-sized pore diameters is the key and difficult point of the current preparation of high-performance porous aluminum alloy.

The existing preparation methods mainly comprise a seepage casting method, a melt foaming method, a selective laser melting method and the like, but the methods cannot thoroughly solve two problems, namely complete removal of a pore-forming agent and precise control of the size and the shape of a pore. Therefore, the research on the preparation method of the novel spherical micron-sized porous aluminum alloy has positive practical significance and good application prospect.

Disclosure of Invention

The invention aims to provide a method for preparing porous aluminum alloy, which is simple to operate, does not need to remove pore-forming agents, and has controllable pore size and porosity aiming at the problems existing in the preparation of spherical micron-sized porous aluminum alloy at present.

The invention firstly proposes to use the alumina hollow microspheres to prepare the porous aluminum alloy; the method is not only simple and controllable, but also the obtained product has excellent performance, especially the compression resistance of the product, and the performance of the product is far superior to that of the similar product under the condition of the same porosity.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, which comprises the following steps:

a) the method comprises the following steps of (1) taking alumina hollow microspheres as a pore-forming agent, filling the alumina hollow microspheres and aluminum alloy powder into a closed container according to a certain volume ratio in a glove box under a protective atmosphere, and fully mixing to obtain uniformly mixed alumina hollow microspheres and aluminum alloy precursor powder;

b) and (3) adopting vacuum hot-pressing sintering, uniformly putting the alumina hollow microspheres and the aluminum alloy precursor powder into a mould, and controlling sintering parameters and pressure to obtain the uniform spherical-pore porous aluminum alloy with certain porosity.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the protective atmosphere in the step a) is one of argon atmosphere and helium atmosphere.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the outer diameter of the alumina hollow microspheres in the step a) is 10-200 mu m.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the wall thickness of the alumina hollow microspheres in the step a) is 1-10 mu m; and the wall thickness of the alumina hollow microsphere is smaller than the inner diameter of the alumina hollow microsphere.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the aluminum alloy powder in the step a) is 2A12 or 2024 aluminum alloy powder.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the material mixing time in the step a) is 1-10 h.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the bulk density of the alumina hollow spheres in the step a) is 0.1g/cm³-1.5g/cm³。

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the volume ratio of aluminum oxide hollow microspheres to aluminum alloy powder in the step a) is 1:9-9: 1. When the volume ratio of the alumina hollow microspheres to the aluminum alloy powder in the step a) is 1-3: 9-7, the compressive strength of the obtained product is more than or equal to 400 MPa.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the sintering temperature in the step b) is 550-650 ℃, and the heat preservation time is 1-5 h.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the sintering pressure in the step b) is 1-100 MPa, preferably 1-10MPa, and more preferably 1-5 MPa. In the invention, the cracking of the alumina hollow microspheres can be caused by the excessive pressure during sintering; thereby causing the porosity of the product to be uncontrollable.

The invention relates to a method for preparing porous aluminum alloy by utilizing hollow microspheres, wherein the porosity of the porous aluminum alloy in the step b) is 10-90%.

According to the method for preparing the porous aluminum alloy by using the hollow microspheres, more than 90% of pores in the obtained product are closed pores. Pores that exist as closed pores; in the collision process, the energy absorbed by the material is far greater than that of the open pores, so that the material prepared by the invention is particularly suitable for energy absorption parts of vehicles.

The invention solves the problems that the pore-forming agent is difficult to remove and the size and the shape of the pores are difficult to accurately control, and the prepared porous aluminum alloy has uniform pore distribution, spherical pores and micron-sized pore diameters; simple process, flexible operation and low cost.

The invention has the advantages that

1. According to the invention, the alumina hollow microspheres are used as the pore-forming agent, the advantage of spherical pores of the pore-forming agent is utilized, uniform spherical pores can be formed without removing the pore-forming agent, and the problems of residual pore-forming agent, irregular pore shape, influence of the removal process on the substrate and the like are solved.

2. The invention can control the aperture size and porosity of the porous aluminum alloy by adjusting the size and the addition amount of the pore-forming agent. The deviation between the porosity of the product and the designed porosity is less than or equal to 5 percent, namely (the porosity of the product-the designed porosity)/the designed porosity is less than or equal to 0.05. Especially, when the designed porosity is more than or equal to 50%, the deviation of the porosity of the product can be less than or equal to 5%.

3. The invention has simple process, flexible operation and lower cost.

Drawings

FIG. 1 is a scanning electron micrograph of alumina hollow microspheres used in example 1 of the present invention.

FIG. 2 is a scanning electron micrograph of the wall thickness of the alumina hollow microspheres used in example 1 of the present invention.

FIG. 3 is a scanning electron micrograph of the porous aluminum alloy prepared in example 1 of the present invention.

FIG. 4 is a compressive stress-strain curve of the porous aluminum alloy prepared in example 1 of the present invention.

FIG. 5 is a compressive stress-strain curve of the porous aluminum alloy prepared in example 2 of the present invention.

FIG. 6 is a compressive stress-strain curve of the porous aluminum alloy prepared in example 3 of the present invention.

As can be seen from FIG. 1, the alumina hollow microspheres used in example 1 of the present invention had an average particle size of about 50 μm and were in a regular spherical shape.

As can be seen from FIG. 2, the wall thickness of the hollow alumina microspheres used in example 1 of the present invention is about 2 to 6 μm, and the distribution is uniform.

As can be seen from FIG. 3, the porous aluminum alloy prepared in example 1 of the present invention has uniform pore distribution, spherical pores, and pore size distribution below 50 μm.

It can be seen from fig. 4 that the porous aluminum alloy prepared in example 1 of the present invention has good compression properties. Wherein 3 curves represent the results of 3 repetitions of the measurement; the degree of coincidence is very high from the point of view of the degree of coincidence of the 3 curves.

It can be seen from fig. 5 and 6 that the compressive strength of the porous aluminum alloys prepared in examples 2 and 3 of the present invention is decreased and the compression property is decreased as the porosity is increased. Both fig. 5 and 6 contain 3 curves; these 3 curves represent the results of 3 repetitions of the measurement. Comparing fig. 4, 5 and 6, it can be seen that the compressive strength and stability of the product obtained in example 1 are far superior to those of examples 2 and 3.

Detailed Description

The invention will be further illustrated by the following examples, without limiting the scope of the invention thereto.