阅读说明：本技术 一种高强韧性单壁碳纳米管铝合金基复合材料及其制备方法 (High-toughness single-walled carbon nanotube aluminum alloy-based composite material and preparation method thereof ) 是由 徐文雷 刘爱军 于 2020-07-02 设计创作，主要内容包括：一种高强韧性单壁碳纳米管铝合金基复合材料,其质量百分数为：单壁碳纳米管0.1％～0.5％,铝合金基体99.5％～99.9％；其铝合金基体预合金粉末为6系或7系变形铝合金,平均粒度为1微米～30微米；本发明还提该复合材料的制备方法,主要步骤为S1原料称取,S2原料混合,S3热压烧结,其烧结温度为450℃～520℃,烧结压力为5MPa～20MPa；S4热轧加工,热轧温度为350℃～450℃,热轧变形量为20％～80％；该复合材料在粉末烧结过程中,单壁碳纳米管在铝合金基体中通过扩散再结晶过程而进一步均匀分布,充分提高了强度；而经过热轧实现复合材料的致密化,进一步提高该复合材料的强度和塑性。(A high-toughness single-walled carbon nanotube aluminum alloy-based composite material comprises the following components in percentage by mass: 0.1 to 0.5 percent of single-walled carbon nanotube and 99.5 to 99.9 percent of aluminum alloy matrix; the pre-alloyed powder of the aluminum alloy matrix is 6 series or 7 series wrought aluminum alloy, and the average particle size is 1-30 microns; the invention also provides a preparation method of the composite material, which mainly comprises the steps of weighing S1 raw materials, mixing S2 raw materials, and carrying out hot-pressing sintering on S3, wherein the sintering temperature is 450-520 ℃, and the sintering pressure is 5-20 MPa; s4, hot rolling, wherein the hot rolling temperature is 350-450 ℃, and the hot rolling deformation is 20-80%; in the powder sintering process of the composite material, the single-walled carbon nanotubes are further uniformly distributed in the aluminum alloy matrix through a diffusion recrystallization process, so that the strength is fully improved; and the densification of the composite material is realized through hot rolling, so that the strength and the plasticity of the composite material are further improved.)

1. A high-toughness single-walled carbon nanotube aluminum alloy-based composite material comprises the following components in percentage by mass:

single-walled carbon nanotubes: 0.1 to 0.5 percent;

aluminum alloy matrix: 99.5 to 99.9 percent;

wherein the aluminum alloy matrix is pre-alloyed powder.

2. The high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 1, wherein: the pipe diameter of the single-walled carbon nanotube is 1-20 nanometers, and the length of the single-walled carbon nanotube is 0.5-30 micrometers.

3. The high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 1, wherein: the aluminum alloy substrate is 6 series wrought aluminum alloy or 7 series wrought aluminum alloy; the pre-alloyed powder has an average particle size of 1 to 30 microns.

4. The high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in any one of claims 1 to 3, wherein: 0.1 to 1 percent of dispersant is also added into the pre-alloyed powder raw material.

5. The high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 3, wherein: the 6-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：0.4％～0.8％；

Zn：≤0.25％；

Cu：0.15％～0.4％；

Mg：0.8％～1.2％；

Mn：≤0.15％；

Ti：≤0.15％；

cr: 0.04 to 0.35 percent; the balance of Al;

the 7-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：≤0.4％；

Zn：5.1％～6.1％；

Cu：1.2％～2.0％；

Mg：2.1％～2.9％；

Mn：≤0.3％；

Ti：≤0.2％；

Cr：0.18％～0.28％；

fe: less than or equal to 0.5 percent; the balance being Al.

6. A preparation method of a high-toughness single-walled carbon nanotube aluminum alloy-based composite material comprises the following steps:

s1 raw material weighing, namely weighing 0.1-0.5% of single-walled carbon nanotube and 99.5-99.9% of aluminum alloy matrix;

mixing S2 raw materials, and uniformly mixing the single-walled carbon nanotube weighed by S1 and the aluminum alloy matrix raw material in a mixing device to obtain mixed powder;

s3, carrying out hot-pressing sintering, namely carrying out vacuum hot-pressing sintering on the powder uniformly mixed with the S2, wherein the sintering temperature is 450-520 ℃, the sintering pressure is 5-20 MPa, and the sintering time is 0.5-2 hours, so as to obtain a composite blank;

s4, carrying out hot rolling processing on the composite blank material S3, wherein the hot rolling temperature is 350-450 ℃, and the hot rolling deformation is 20-80%;

and S5 aluminum alloy matrix composite, naturally cooling the S4 hot-rolled composite in air or inert gas to obtain the aluminum alloy matrix composite.

7. The preparation method of the high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 6, wherein the preparation method comprises the following steps: and S1, dispersing the single-walled carbon nanotubes into the pre-alloyed powder of the aluminum alloy matrix by ultrasonic waves, wherein the dispersion time of the ultrasonic waves is 1-3 hours.

8. The preparation method of the high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 6, wherein the preparation method comprises the following steps: and step S2, the mixing device adopts a vacuum dry grinding mode, the mixing time is 1-3 hours, and the mixing speed is 200-300 rpm.

9. The preparation method of the high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in claim 6, wherein the preparation method comprises the following steps: and S3, the hot-pressing sintering is to put the mixed powder into a steel mould to be pressurized in two directions, put the mixed powder into a sintering furnace to be sintered in vacuum, wherein the sintering temperature is 480-500 ℃, the sintering pressure is 10-15 MPa, and the sintering time is 1-1.5 hours.

10. The preparation method of the high-toughness single-walled carbon nanotube aluminum alloy-based composite material as claimed in any one of claims 6 to 9, wherein the preparation method comprises the following steps: the hot rolling temperature of the hot rolling processing of the step S4 is 400-450 ℃, and the hot rolling deformation is 60-80%.

Technical Field

The invention relates to the technical field of aluminum alloy base composite material processing, in particular to a high-toughness single-walled carbon nanotube aluminum alloy base composite material and a preparation method thereof.

Background

In the technical field of reinforced base composite materials, the aluminum alloy base composite material has the characteristics of high specific strength and specific modulus, low thermal expansion coefficient and good high-temperature performance, and has good fatigue resistance and wear resistance; meanwhile, the aluminum alloy matrix composite material has the advantages of wide selection range of the matrix, mature material processing technology, excellent plastic forming performance, good heat treatment performance and easy processing and preparation. Has become an important direction for the research and development of high-performance materials in aviation, aerospace and other advanced technical departments, and is also one of the hot spots for the research of new materials at home and abroad in recent years. Through the optimization design of the components, the content and the distribution of the matrix and the reinforcing phase of the aluminum alloy matrix composite material, specific mechanical properties and physical properties can be combined to meet the requirements of different product properties. Therefore, the development of the aluminum alloy-based composite material with excellent performance has very urgent practical significance and has remarkable economic and social benefits.

The single-walled carbon nanotube has excellent physical properties, nanoscale size and chemical properties, and the conductivity of the material is enhanced while the strength of the material is improved. The addition of small amounts of single-walled carbon nanotubes significantly improves the material properties compared to conventional additives such as multi-walled carbon nanotubes, carbon fibers and most types of carbon black. Therefore, the invention provides the composite material with better performance and higher production efficiency and the preparation method thereof, which are the key for further expanding the application field of the single-walled carbon nanotube for preparing the aluminum alloy matrix composite material.

Chinese patent CN109536780A provides a method for preparing a carbon nanotube reinforced zinc-aluminum alloy based composite material, which mainly comprises the following three steps: firstly, preparing CNTs-Zn (carbon nano tube-zinc base) composite powder; secondly, preparing a CNTs-Zn intermediate material; and thirdly, smelting. Finally, the carbon nano tube reinforced zinc-aluminum alloy base composite material is obtained. At present, the single-walled carbon nanotube reinforced aluminum alloy matrix composite prepared by powder metallurgy has not seen relevant standards and commercial application brands. In particular, the aluminum alloy matrix composite material formed by compounding single-wall carbon nano tubes with different coarse and fine grains has fewer commercial products. Therefore, the invention discloses a high-toughness single-walled carbon nanotube aluminum alloy-based composite material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the high-toughness single-walled carbon nanotube aluminum alloy matrix composite, wherein the single-walled carbon nanotube is used as a reinforcing phase, so that materials with two scales in an aluminum alloy matrix are compounded, the toughness of the aluminum alloy matrix is effectively improved, and the strength of the aluminum alloy matrix is greatly improved, so that the high-toughness single-walled carbon nanotube aluminum alloy matrix composite is formed. Meanwhile, the invention also provides a preparation method for preparing the high-toughness single-walled carbon nanotube aluminum alloy matrix composite, during the powder sintering process of the composite, the single-walled carbon nanotubes are further uniformly distributed in the aluminum alloy matrix through a diffusion recrystallization process, so that the strength of the composite is fully improved; coarse-grained aluminum alloy grains and fine-grained aluminum alloy grains in the aluminum alloy matrix are compounded in a staggered mode, and the toughness of the matrix is improved. And the densification of the composite material is further realized through hot rolling, so that the strength and the plasticity of the composite material are further improved.

In order to realize the aim, the invention provides a high-toughness single-walled carbon nanotube aluminum alloy-based composite material, which comprises the following components in percentage by mass:

single-walled carbon nanotubes: 0.1 to 0.5 percent;

aluminum alloy matrix: 99.5 to 99.9 percent;

wherein the aluminum alloy matrix is pre-alloyed powder; the aluminum alloy matrix is one or a mixture of 6 series wrought aluminum alloy or 7 series wrought aluminum alloy, and the mixture ratio is 0-1.2; the average grain size of the prealloyed powder of the 6 series wrought aluminum alloy or the 7 series wrought aluminum alloy is the same or different and is compounded with the single-walled carbon nanotube.

Further, the 6-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：0.4％～0.8％；

Zn：≤0.25％；

Cu：0.15％～0.4％；

Mg：0.8％～1.2％；

Mn：≤0.15％；

Ti：≤0.15％；

cr: 0.04 to 0.35 percent; the balance being Al.

Further, the 7-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：≤0.4％；

Zn：5.1％～6.1％；

Cu：1.2％～2.0％；

Mg：2.1％～2.9％；

Mn：≤0.3％；

Ti：≤0.2％；

Cr：0.18％～0.28％；

fe: less than or equal to 0.5 percent; the balance being Al.

Preferably, the 6-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：0.55％；

Zn：0.15％；

Cu：0.3％；

Mg：1.05％；

Mn：0.1％；

Ti：0.1％；

cr: 0.25 percent; the balance being Al.

Preferably, the 7-series wrought aluminum alloy comprises the following components in percentage by mass:

Si：0.4％；

Zn：5.68％；

Cu：1.82％；

Mg：2.55％；

Mn：0.25％；

Ti：0.15％；

Cr：0.22％；

fe: 0.35 percent; the balance being Al.

Furthermore, the pipe diameter of the single-walled carbon nanotube is 1-20 nanometers, and the length of the single-walled carbon nanotube is 0.5-30 micrometers;

further, the pre-alloyed powder of the 6-series wrought aluminum alloy or the 7-series wrought aluminum alloy has an average particle size of 1 to 30 micrometers;

preferably, 0.1 to 1 percent of dispersant is also added into the pre-alloyed powder raw material, and the single-walled carbon nanotube can be fully dispersed into the pre-alloyed powder raw material in ultrasonic wave by combining the preparation method of the aluminum alloy matrix composite material.

Preferably, the dispersant is a polyoxyethylene sorbitol ester, preferably tween 80.

In order to realize the aim, the invention also provides a preparation method for preparing the high-toughness single-walled carbon nanotube aluminum alloy matrix composite material, which comprises the following steps:

s1, weighing raw materials, namely weighing a certain amount of prealloyed powder raw materials of the single-walled carbon nanotube and the aluminum alloy matrix respectively, wherein the aluminum alloy matrix is formed by mixing two different average particle size proportions;

mixing S2 raw materials, and uniformly mixing the single-walled carbon nanotube weighed by S1 and the aluminum alloy matrix raw material in a mixing device to obtain mixed powder;

s3, carrying out hot-pressing sintering, namely carrying out vacuum hot-pressing sintering on the powder uniformly mixed with the S2, wherein the sintering temperature is 450-520 ℃, the sintering pressure is 5-20 MPa, and the sintering time is 0.5-2 hours, so as to obtain a composite blank;

s4, carrying out hot rolling processing on the composite blank material S3, wherein the hot rolling temperature is 350-450 ℃, and the hot rolling deformation is 20-80%; after the composite blank is subjected to hot rolling processing, the internal structure of the obtained composite material is further densified, and the composite material with uniform and fine structure and excellent performance is favorably obtained.

And S5 aluminum alloy matrix composite, naturally cooling the S4 hot-rolled composite in air or inert gas to obtain the aluminum alloy matrix composite.

Preferably, the two different average particle size ratios in step S1 are: 20 to 80 percent;

preferably, in step S1, the single-walled carbon nanotubes are dispersed in the pre-alloyed powder of the aluminum alloy matrix by using ultrasonic waves, and the dispersion time of the ultrasonic waves is 1 to 3 hours;

further, the mixing device in step S2 adopts a vacuum dry grinding mode, the mixing time is 1 hour to 3 hours, and the mixing speed is 200rpm to 300 rpm. So that the raw materials are fully and uniformly mixed.

Further, in the step S3, the hot-pressing sintering is to put the mixed powder into a steel mold to be pressurized in two directions, and put the mixed powder into a sintering furnace to be sintered in vacuum, wherein the sintering temperature is 480-500 ℃, the sintering pressure is 10-15 MPa, and the sintering time is 1-1.5 hours. In the mixed powder sintering process, the single-walled carbon nanotubes are further uniformly distributed in the aluminum alloy matrix through a diffusion recrystallization process, so that the strength of the composite material is fully improved.

Further, the hot rolling temperature of the hot rolling process of step S4 is 400 to 450 ℃, and the hot rolling deformation is 60 to 80%. The strength and the density of the aluminum alloy matrix composite material obtained after hot rolling are both greatly improved. And the densification of the composite material is further realized through hot rolling, so that the strength and the plasticity of the composite material are further improved. Coarse-grained aluminum alloy grains and fine-grained aluminum alloy grains in the aluminum alloy matrix are compounded in a staggered mode, and the toughness of the matrix is improved.

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

1. according to the high-toughness single-walled carbon nanotube aluminum alloy-based composite material, the single-walled carbon nanotubes added by a special preparation method are used as a reinforcing phase, so that the strength of the composite material is greatly improved; meanwhile, due to the hot-pressing sintering and hot-rolling processing steps in the preparation process, sufficient conditions are provided for remelting and recrystallizing the aluminum alloy matrix composite, a small amount of Al4C3 strengthening grains are generated in the aluminum alloy matrix composite, the internal structure of the material is further improved, and the effect of strengthening an aluminum alloy matrix is also achieved. Meanwhile, alloying elements such as Zn, Cu, Mg, Mn, Si and the like are added into the aluminum alloy matrix to form second-phase solid solution strengthening or solid solution dispersion strengthening on the matrix.

2. In addition, two 6 series wrought aluminum alloy components or 7 series wrought aluminum alloy components are adopted, the average particle sizes of the pre-alloyed powders are different, and the pre-alloyed powders are mixed according to a certain average particle size ratio and then form a composite material with the single-wall carbon nano-tubes, so that two average particle size aluminum alloy matrix average particle size tissues are obtained, and coarse particles have higher fracture work, thereby providing higher toughness. The density and the strength of the composite material are further improved through hot-pressing sintering and hot-rolling processing. The test result shows that the tensile strength of the aluminum alloy matrix composite material is 500 MPa-900 MPa, the elongation is 7.5-12%, and the density is 99-100%. The aluminum alloy matrix composite material has excellent comprehensive performance.

3. In the preparation method, in the process of preparing the aluminum alloy matrix composite material, the aluminum alloy matrix composite material is subjected to a powder metallurgy hot-pressing sintering step and a hot-rolling processing step to obtain the high-performance aluminum alloy matrix composite material. In the powder metallurgy hot-pressing sintering process, under the dual actions of thermal diffusion and a dispersing agent, the single-walled carbon nanotubes are uniformly distributed in the aluminum alloy matrix, which is beneficial to improving the strength of the aluminum alloy matrix composite material; the staggered composition of coarse-grained aluminum alloy and fine-grained aluminum alloy in the aluminum alloy matrix is beneficial to improving the toughness of the aluminum alloy matrix. The subsequent hot rolling process further realizes the densification of the aluminum alloy matrix composite material, and simultaneously improves the strength and the plasticity of the material.

Drawings

FIG. 1 is a process flow diagram of a high toughness single-walled carbon nanotube aluminum alloy matrix composite of the present invention;

FIG. 2 shows the morphology of single-walled carbon nanotubes of the high-toughness single-walled carbon nanotube aluminum alloy-based composite material of the present invention;

FIG. 3 shows the shape of the aluminum alloy base material powder of the high-toughness single-walled carbon nanotube aluminum alloy base composite material.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples, so that those skilled in the art can fully understand the technical contents of the present invention. It should be noted that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.