阅读说明：本技术 一种高强高导热铝基复合材料及其制备方法 (High-strength high-thermal-conductivity aluminum-based composite material and preparation method thereof ) 是由 李勇 吴荣辉 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种高强高导热铝基复合材料及其制备方法,该铝基复合材料为铝、二硼化镁与石墨的复合材料。本发明制备方法包括如下步骤：首先将铝粉与二硼化镁粉末混合均匀得到铝-二硼化镁混合物,随后将上述混合物与石墨粉混合均匀得到铝-二硼化镁-石墨混合物。将铝-二硼化镁-石墨混合物进行真空热压烧结,使熔融形成的铝液流动填充于石墨间隙中形成金属骨架,而二硼化镁颗粒则作为增强相均匀分散在铝金属骨架中,从而得到高强高导热铝基复合材料。采用本发明制备的铝基复合材料强度和热导率均较高,并且制备工艺简单、成本低廉、适合大规模生产,具有广泛的应用前景。(The invention discloses a high-strength high-heat-conductivity aluminum-based composite material and a preparation method thereof. The preparation method comprises the following steps: firstly, mixing aluminum powder and magnesium diboride powder uniformly to obtain an aluminum-magnesium diboride mixture, and then mixing the mixture and graphite powder uniformly to obtain the aluminum-magnesium diboride-graphite mixture. And (2) carrying out vacuum hot-pressing sintering on the aluminum-magnesium diboride-graphite mixture, so that molten aluminum liquid flows and fills in graphite gaps to form a metal framework, and the magnesium diboride particles are uniformly dispersed in the aluminum metal framework as a reinforcing phase, thereby obtaining the high-strength high-heat-conductivity aluminum-based composite material. The aluminum-based composite material prepared by the method has high strength and thermal conductivity, simple preparation process, low cost, suitability for large-scale production and wide application prospect.)

1. The high-strength high-thermal-conductivity aluminum-based composite material is characterized by comprising the following components: aluminum, magnesium diboride and graphite.

2. The high-strength high-thermal-conductivity aluminum-based composite material as claimed in claim 1, wherein the aluminum-based composite material comprises the following components in percentage by mass: 40-60% of aluminum, 5-20% of magnesium diboride and 30-50% of graphite.

3. A high-strength high-thermal-conductivity aluminum-based composite material as claimed in claim 1, wherein: in the structure of the aluminum-based composite material, the magnesium diboride particles are uniformly dispersed in the aluminum metal framework, and the graphite is kept in microcosmic horizontal arrangement.

4. A method for preparing a high strength high thermal conductivity aluminum matrix composite as claimed in any one of claims 1 to 3, characterized in that said method comprises the following steps:

(1) adding aluminum powder and magnesium diboride powder into a ball mill according to a certain mass ratio, and ball-milling and mixing uniformly for 3-6 hours to obtain an aluminum-magnesium diboride mixture;

(2) weighing a certain mass of graphite powder, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step (1), and then uniformly stirring in a stirrer for 5-10 minutes each time for 1-3 times;

(3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, and then placing the graphite mold in a vibrator to vibrate the aluminum-magnesium diboride-graphite mixture to keep the graphite in microcosmic parallel arrangement for 10-30 minutes;

(4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 10-30 MPa, the hot pressing temperature is 660-800 ℃, and the hot pressing time is 30-180 minutes, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

5. The preparation method of the high-strength high-thermal-conductivity aluminum-based composite material according to claim 4, characterized by comprising the following steps: in the step (1), the particle size of the aluminum powder is 10-100 microns, and the particle size of the magnesium diboride is 0.1-10 microns.

6. The preparation method of the high-strength high-thermal-conductivity aluminum-based composite material according to claim 4, characterized by comprising the following steps: in the step (2), the particle size of the graphite powder is 100-1000 microns, and the thickness of the graphite powder is 10-50 microns.

7. The preparation method of the high-strength high-thermal-conductivity aluminum-based composite material according to claim 4, characterized by comprising the following steps: and (4) in the vacuum hot-pressing sintering process in the step (4), the oxygen content in the hot-pressing furnace is less than or equal to 1 ppm.

Technical Field

The invention belongs to the technical field of heat-conducting and heat-dissipating materials, and particularly relates to a high-strength high-heat-conducting aluminum-based composite material and a preparation method thereof.

Background

With the popularization and application of the 5G technology and the intelligent technology, electronic components are developing towards miniaturization, integration, high power, multiple functions and space compactness, and the heat dissipation problem and the performance attenuation and safety problem caused by the heat dissipation problem are put on more and more prominent positions, so that the requirements on heat dissipation materials are higher and higher. The aluminum-graphite composite material in the aluminum-based composite material is a novel excellent heat conduction and dissipation material, and has attracted extensive attention due to the properties of high heat conductivity, low thermal expansion coefficient, low density and the like. However, the brittleness of graphite is high, and the wettability between graphite and aluminum is poor, so that the strength of the aluminum-graphite composite material is too low, the aluminum-graphite composite material is difficult to mold, and the mass production and the use are not facilitated.

Disclosure of Invention

Aiming at the defects and problems in the prior art, the invention aims to provide a high-strength high-heat-conductivity aluminum-based composite material and a preparation method thereof.

The invention provides a high-strength high-heat-conductivity aluminum-based composite material, which comprises the following components in percentage by mass: 40-60% of aluminum, 5-20% of magnesium diboride and 30-50% of graphite.

Preferably, in the structure of the aluminum matrix composite, the magnesium diboride particles are uniformly dispersed in the aluminum metal framework, and the graphite is kept in a horizontal arrangement on a microscopic scale.

The invention also provides a preparation method of the high-strength high-heat-conductivity aluminum-based composite material, which comprises the following steps:

(1) adding aluminum powder and magnesium diboride powder into a ball mill according to a certain mass ratio, and ball-milling and mixing uniformly for 3-6 hours to obtain an aluminum-magnesium diboride mixture;

(2) weighing a certain mass of graphite powder, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step (1), and then uniformly stirring in a stirrer for 5-10 minutes each time for 1-3 times;

(3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, and then placing the graphite mold in a vibrator to vibrate the aluminum-magnesium diboride-graphite mixture to keep the graphite in microcosmic parallel arrangement for 10-30 minutes;

(4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 10-30 MPa, the hot pressing temperature is 660-800 ℃, and the hot pressing time is 30-180 minutes, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Preferably, in the step (1), the particle size of the aluminum powder is 10-100 microns, and the particle size of the magnesium diboride is 0.1-10 microns.

Preferably, in the step (2), the particle size of the graphite powder is 100-1000 microns, and the thickness of the graphite powder is 10-50 microns.

Preferably, in the vacuum hot-pressing sintering process in the step (4), the oxygen content in the hot-pressing furnace is less than or equal to 1 ppm.

Compared with the prior art, the invention has the beneficial effects that:

(1) the aluminum matrix composite material prepared by the invention has the advantages of high thermal conductivity, controllable thermal expansion coefficient, excellent mechanical property and processing property and the like; the high-strength high-thermal-conductivity aluminum-based composite material is verified to have the thermal conductivity of 300-600W/m.K in the direction parallel to the X-Y direction of graphite, the thermal expansion coefficient of 6-15 ppm/K, the bending strength of the composite material can be 60-220 MPa, and the requirement on the use mechanical property is met.

(2) The preparation method of the high-strength high-heat-conductivity aluminum-based composite material is simple to operate, easy to implement, low in equipment requirement, free of toxic and harmful intermediate products, capable of meeting the requirement of modern industry on environmental protection, convenient to implement large-scale production and promising in commercial application prospect.

(3) According to the invention, magnesium diboride is added into the aluminum metal framework, so that on one hand, the strength of the composite material can be improved by taking the magnesium diboride as a reinforcing phase, and the processing performance and the service performance of the composite material are improved; on the other hand, the magnesium diboride has higher thermal conductivity, so that the composite material can still maintain better heat dissipation performance; meanwhile, because the mass density of the magnesium diboride is close to that of aluminum, the uniform mixing of the magnesium diboride and aluminum powder can be easily realized, the uniform distribution of the magnesium diboride in an aluminum metal framework is further realized, and the large-scale preparation of the composite material is convenient; in addition, the magnesium diboride can form relatively close contact with the aluminum and the graphite, so that the mechanical property of the composite material is further improved.

Detailed Description

The invention is further illustrated by the following specific examples, which, however, are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

The preparation method of the high-strength high-heat-conductivity aluminum-based composite material comprises the following steps:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride (40-60) to (5-20), ball-milling and mixing uniformly, and ball-milling for 3-6 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 10-100 micrometers, and the particle size of the magnesium diboride is 0.1-10 micrometers;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of (40-60) to (5-20) to (30-50), adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then stirring and uniformly mixing in a stirrer for 5-10 minutes for 1-3 times, wherein the particle size of the graphite powder is 100-1000 micrometers, and the thickness of the graphite powder is 10-50 micrometers;

3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, and then placing the graphite mold in a vibrator to uniformly mix the aluminum-magnesium diboride-graphite mixture in a vibrating manner for 10-30 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 10-30 MPa, the hot pressing temperature is 660-800 ℃, the hot pressing time is 30-180 minutes, and the oxygen content in the hot pressing furnace is less than or equal to 1ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

The materials used in the present invention and the test methods are generally described. Although many materials and methods of operation are known in the art for the purpose of carrying out the invention, the invention is nevertheless described herein in as detail as possible. It will be apparent to those skilled in the art that the materials and methods of operation used in the present invention are well within the skill of the art, provided that they are not specifically illustrated.

Example 1:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride being 40: 10, ball-milling and mixing uniformly, and ball-milling for 3 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 10 microns, and the particle size of the magnesium diboride is 0.1 micron;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of 40: 10: 50, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 5 minutes for 3 times, wherein the particle size of the graphite powder is 100 micrometers, and the thickness of the graphite powder is 10 micrometers;

3) placing the aluminum-magnesium diboride-graphite mixture into a graphite mold, then placing the graphite mold into a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 30 minutes;

4) and (2) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 10 MPa, the hot pressing temperature is 660 ℃, the hot pressing time is 180 minutes, and the oxygen content in the hot pressing furnace is 1ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Example 2:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride of 60: 5, ball-milling and mixing uniformly, and ball-milling for 6 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 100 microns, and the particle size of the magnesium diboride is 10 microns;

2) weighing graphite powder with a certain mass ratio of aluminum to magnesium diboride to graphite of 60: 5: 35, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 10 minutes for 1 time, wherein the particle size of the graphite powder is 1000 microns, and the thickness of the graphite powder is 50 microns;

3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, then placing the graphite mold in a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 10 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 30 MPa, the hot pressing temperature is 800 ℃, the hot pressing time is 30 minutes, and the oxygen content in the hot pressing furnace is 0.1ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Example 3:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride being 50: 20, ball-milling and mixing uniformly, and ball-milling for 5 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 20 microns, and the particle size of the magnesium diboride is 1 micron;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of 50: 20: 30, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 6 minutes for 2 times, wherein the particle size of the graphite powder is 300 microns, and the thickness of the graphite powder is 20 microns;

3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, then placing the graphite mold in a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 15 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 15 MPa, the hot pressing temperature is 700 ℃, the hot pressing time is 60 minutes, and the oxygen content in the hot pressing furnace is 0.5ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Example 4:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride being 55: 15, ball-milling and mixing uniformly, and ball-milling for 3-6 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 10-100 microns, and the particle size of the magnesium diboride is 0.1-10 microns;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of 55: 15: 30, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 8 minutes for 2 times, wherein the particle size of the graphite powder is 500 micrometers, and the thickness of the graphite powder is 30 micrometers;

3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, then placing the graphite mold in a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 20 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 25 MPa, the hot pressing temperature is 720 ℃, the hot pressing time is 100 minutes, and the oxygen content in the hot pressing furnace is 0.8ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Example 5:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride of 50: 10, ball-milling and mixing uniformly, and ball-milling for 4 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 60 microns, and the particle size of the magnesium diboride is 6 microns;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of 50: 10: 40, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 7 minutes for 3 times, wherein the particle size of the graphite powder is 600 micrometers, and the thickness of the graphite powder is 40 micrometers;

3) placing the aluminum-magnesium diboride-graphite mixture in a graphite mold, then placing the graphite mold in a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 20 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 20 MPa, the hot pressing temperature is 690 ℃, the hot pressing time is 120 minutes, and the oxygen content in the hot pressing furnace is 0.3ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

Example 6:

1) adding aluminum powder and magnesium diboride powder into a ball mill according to the mass ratio of aluminum to magnesium diboride being 45: 15, ball-milling and mixing uniformly, and ball-milling for 3 hours to obtain an aluminum-magnesium diboride mixture, wherein the particle size of the aluminum powder is 80 microns, and the particle size of the magnesium diboride is 8 microns;

2) weighing certain mass of graphite powder according to the mass ratio of aluminum to magnesium diboride to graphite of 45: 15: 40, adding the graphite powder into the aluminum-magnesium diboride mixture obtained in the step 1), and then uniformly stirring in a stirrer for 10 minutes for 3 times, wherein the particle size of the graphite powder is 900 micrometers, and the thickness of the graphite powder is 45 micrometers;

3) placing the aluminum-magnesium diboride-graphite mixture into a graphite mold, then placing the graphite mold into a vibrator, and vibrating and uniformly mixing the aluminum-magnesium diboride-graphite mixture for 30 minutes;

4) and (3) placing the graphite mold in a hot pressing furnace for vacuum hot pressing sintering, wherein the hot pressing strength is 150 MPa, the hot pressing temperature is 750 ℃, the hot pressing time is 80 minutes, and the oxygen content in the hot pressing furnace is 0.9ppm, so that the high-strength high-heat-conductivity aluminum-based composite material is obtained.

While the above is a detailed description of the process steps in the preferred embodiment of the invention, it will be apparent to those skilled in the art that insubstantial changes in form and detail may be made in the steps recited above without departing from the spirit and scope of the invention, and therefore the invention is not limited to the specific forms and details set forth above.