阅读说明：本技术 一种固液法制备碳纳米管增强铝基复合材料的方法 (Method for preparing carbon nano tube reinforced aluminum matrix composite material by solid-liquid method ) 是由 陈彪 贾振东 万杰 曹遴 李金山 贾磊 寇宏超 王军 唐斌 樊江昆 赖敏杰 于 2021-09-18 设计创作，主要内容包括：本发明公开了一种固液法制备碳纳米管增强铝基复合材料的方法,包括将铝粉、碳纳米管和过程控制剂进行高能球磨混合得到复合材料混合粉末；将上述粉末置于模具中压实后进行烧结,然后随炉冷却至40℃时取出得复合材料前驱体；以一定的稀释比例将复合材料前驱体加入铝液中,待炉体温度重新到达所设定温度后保温预先设定的时长；之后进行搅拌处理；待炉体温度重新到达所设定温度后再次保温,浇入模具中凝固制得碳纳米管增强铝基复合材料铸锭；将铸锭在一定温度下保温一定时间后进行热挤压,制得最终碳纳米管增强铝基复合材料。本发明解决了采用熔铸法制备碳纳米管增强铝基复合材料时碳纳米管在铝液中浮起团聚、难以被润湿、反应严重等问题。(The invention discloses a method for preparing a carbon nano tube reinforced aluminum-based composite material by a solid-liquid method, which comprises the steps of carrying out high-energy ball milling and mixing on aluminum powder, a carbon nano tube and a process control agent to obtain composite material mixed powder; placing the powder in a mould, compacting, sintering, cooling to 40 ℃ along with a furnace, and taking out to obtain a composite material precursor; adding the composite material precursor into the aluminum liquid according to a certain dilution ratio, and preserving heat for a preset time after the temperature of the furnace body reaches the set temperature again; then stirring treatment is carried out; preserving heat again after the temperature of the furnace body reaches the set temperature again, pouring the furnace body into a mold for solidification to prepare a carbon nano tube reinforced aluminum matrix composite ingot; and (3) carrying out heat extrusion on the cast ingot after keeping the temperature for a certain time at a certain temperature to obtain the final carbon nano tube reinforced aluminum matrix composite. The invention solves the problems of floating and agglomeration of the carbon nano tube in the aluminum liquid, difficult wetting, serious reaction and the like when the carbon nano tube reinforced aluminum-based composite material is prepared by adopting a fusion casting method.)

1. A method for preparing a carbon nano tube reinforced aluminum matrix composite material by a solid-liquid method is characterized by comprising the following steps:

preparing composite material mixed powder: carrying out high-energy ball milling and mixing on aluminum powder, carbon nano tubes and a process control agent in a certain proportion to obtain composite material mixed powder;

preparing a composite material precursor: placing the composite material mixed powder into a mold to be compacted, then sintering, and then taking out a composite material mixed powder sample when the composite material mixed powder is cooled to 40 ℃ along with a furnace to obtain a composite material precursor;

preparing a composite material by a solid-liquid method: adding the composite material precursor into the completely molten aluminum liquid according to a certain dilution ratio, pressing the precursor into the aluminum liquid, and preserving heat for a preset time after the furnace body temperature reaches the set temperature again; then stirring for a certain period of time; preserving heat for a certain time after the temperature of the furnace body reaches the set temperature again, pouring the furnace body into a mold, and solidifying to obtain a carbon nano tube reinforced aluminum matrix composite ingot;

thermal mechanical treatment: and (3) preserving the heat of the carbon nano tube reinforced aluminum matrix composite ingot at a certain temperature for a certain time, and then carrying out hot extrusion at a certain extrusion ratio and extrusion speed to obtain the final carbon nano tube reinforced aluminum matrix composite.

2. The method for preparing the carbon nanotube reinforced aluminum matrix composite material according to claim 1, wherein the aluminum powder is spherical pure aluminum powder of 15-53 um; the carbon nano tube is a multi-wall carbon nano tube with the tube diameter of 10-30 nm, and the mass fraction of the carbon nano tube is more than 0% and less than or equal to 10%; the process control agent is stearic acid, and the mass fraction of the process control agent is more than 0% and less than or equal to 5%.

3. The method for preparing the carbon nanotube reinforced aluminum matrix composite material according to the solid-liquid method of claim 1, wherein the specific process parameters of the high-energy ball milling process are as follows: planetary ball milling, a 500mL zirconia ball milling tank and 10mm zirconia balls, wherein the ball-material ratio is 5:1, the rotating speed is 200rpm, the argon atmosphere protection is adopted, the ball milling time is 8-48 h, and the ball milling mode is as follows: rotating positively for 10 min-standing for 10 min-rotating negatively for 10 min-standing for 10min, circulating in a cycle, ball-milling for 2h, and standing for 1 h; and after the high-energy ball milling is finished, cooling the ball milling tank for 8 hours at room temperature, and then taking powder in a glove box filled with argon.

4. The method for preparing the carbon nanotube reinforced aluminum matrix composite material by the solid-liquid method according to claim 1, wherein the specific process of placing the composite material mixed powder in a mold for compaction and then sintering comprises the following steps:

and placing the composite material mixed powder into a graphite mould with graphite paper, placing the graphite mould on a prepress for prepressing and compacting, and then sintering by adopting a spark plasma sintering process.

5. The method for preparing the carbon nanotube reinforced aluminum matrix composite material by the solid-liquid method according to claim 4, wherein the pre-pressing is performed under a pre-pressing pressure of 2 to 10MPa for 1 to 15 min; the discharge plasma sintering process is carried out under the condition that the vacuum degree is less than 10^-2The sintering is carried out in a vacuum atmosphere of Pa, the sintering pressure is 30-40 Mpa, and the sintering temperature is 550-610 ℃; the sintering process is divided into two steps, the temperature is increased to 40 ℃ below the target sintering temperature at the temperature increase rate of 55 ℃/min, then the temperature is increased to the target sintering temperature at the temperature increase rate of 4 ℃/min, and the sintering time is 20-60 min.

6. The method for preparing the carbon nanotube reinforced aluminum matrix composite material by the solid-liquid method according to claim 1, wherein the preparation process of the aluminum liquid is as follows:

after the pure aluminum block is melted at the set temperature, oxide skin on the surface of the aluminum liquid is removed, and the completely melted aluminum liquid is exposed.

7. The method for preparing the carbon nanotube reinforced aluminum matrix composite material according to claim 6, wherein the set temperature is 680-850 ℃; the dilution ratio is the mass ratio of the pure aluminum block to the composite material precursor, and the ratio is 1: 1-20: 1; and after the precursor is added, the preset time duration in the heat preservation stage is 5-60 min.

8. The method for preparing the carbon nanotube reinforced aluminum matrix composite material by the solid-liquid method according to claim 1, wherein the stirring treatment is ultrasonic vibration stirring or mechanical blade stirring, wherein the ultrasonic power is 10W-10 kW, the ultrasonic frequency is 10kHZ-30kHZ, the stirring speed of the blade stirring is 100-1000 rpm, and the stirring time is 10 s-12 min.

9. The solid-liquid method for preparing the carbon nanotube reinforced aluminum matrix composite according to claim 1, wherein the time of the secondary heat preservation stage after the stirring treatment is 30s to 10 min.

10. The solid-liquid method for producing a carbon nanotube-reinforced aluminum-based composite material according to claim 1, wherein in the thermo-mechanical treatment: the heat preservation temperature is 300-550 ℃; the heat preservation time is 10-30 min; the extrusion ratio is 10: 1-33: 1; the extrusion speed is 1-10 mm/s.

Technical Field

The invention belongs to the technical field of metal matrix composite preparation, and particularly relates to a method for preparing a carbon nano tube reinforced aluminum matrix composite by a solid-liquid method.

Background

Aluminum and aluminum alloy are key materials in the national important fields of aerospace and the like due to excellent properties of light weight, high heat conductivity, corrosion resistance and the like. The composite material taking the aluminum and the aluminum alloy as the matrix not only inherits the excellent characteristics, but also has the performances of high specific strength, high specific modulus, low thermal expansion coefficient, high temperature creep resistance, fatigue resistance, wear resistance and the like, and has wide application prospects in the fields of aerospace, traffic and the like. The one-dimensional material carbon nano tube has the physical characteristics of light weight, ultrahigh strength, modulus, large length-diameter ratio, high specific surface area, excellent heat conduction and electric conduction and the like, so that the carbon nano tube reinforced aluminum-based composite material is expected to become a next-generation light-weight high-strength structural material.

In recent years, researchers have made a lot of researches on the preparation, mechanical behavior and other aspects of the carbon nanotube reinforced aluminum matrix composite, and the carbon nanotube reinforced aluminum matrix composite with excellent performances such as high strength, high elastic modulus and the like is prepared by using a powder metallurgy method. However, due to the high price of the raw material of the carbon nanotube, the engineering application requirements of the carbon nanotube reinforced aluminum matrix composite material are expected to be met by reducing the preparation cost. Compared with powder metallurgy, the fusion casting method is easier for large-size and large-scale production, and realizes the low-cost large-scale preparation of the carbon nanotube reinforced aluminum matrix composite. However, the carbon nanotube is difficult to be wetted and react due to the problems of floating and agglomeration of the carbon nanotube in the aluminum liquid, and the like, and the traditional casting method is difficult to reliably prepare the carbon nanotube reinforced aluminum matrix composite.

Disclosure of Invention

The invention provides a method for preparing a carbon nano tube reinforced aluminum-based composite material by a solid-liquid method, aiming at the problems that large-size and large-scale production are difficult to realize when a powder metallurgy method is adopted to prepare the carbon nano tube reinforced aluminum-based composite material, and carbon nano tubes float and agglomerate in aluminum liquid, are difficult to wet, react seriously and the like when a fusion casting method is adopted to prepare the carbon nano tube reinforced aluminum-based composite material in the prior art.

The invention is realized by the following technical scheme:

the method for preparing the carbon nano tube reinforced aluminum matrix composite material by the solid-liquid method comprises the following steps:

preparing composite material mixed powder: carrying out high-energy ball milling and mixing on aluminum powder, carbon nano tubes and a process control agent in a certain proportion to obtain composite material mixed powder;

preparing a composite material precursor: placing the composite material mixed powder into a mold to be compacted, then sintering, and then taking out a composite material mixed powder sample when the composite material mixed powder is cooled to 40 ℃ along with a furnace to obtain a composite material precursor;

preparing a composite material by a solid-liquid method: adding the composite material precursor into the completely molten aluminum liquid according to a certain dilution ratio, pressing the precursor into the aluminum liquid, and preserving heat for a preset time after the furnace body temperature reaches the set temperature again; then stirring for a certain period of time; preserving heat for a certain time after the temperature of the furnace body reaches the set temperature again, pouring the furnace body into a mold, and solidifying to obtain a carbon nano tube reinforced aluminum matrix composite ingot;

thermal mechanical treatment: and (3) preserving the heat of the carbon nano tube reinforced aluminum matrix composite ingot at a certain temperature for a certain time, and then carrying out hot extrusion at a certain extrusion ratio and extrusion speed to obtain the final carbon nano tube reinforced aluminum matrix composite.

As a further illustration of the invention, the aluminum powder is spherical pure aluminum powder of 15-53 um; the carbon nano tube is a multi-wall carbon nano tube with the tube diameter of 10-30 nm, and the mass fraction of the carbon nano tube is more than 0% and less than or equal to 10%; the process control agent is stearic acid, and the mass fraction of the process control agent is more than 0% and less than or equal to 5%.

As a further explanation of the present invention, the specific process parameters of the high energy ball milling process are as follows: planetary ball milling, a 500mL zirconia ball milling tank and 10mm zirconia balls, wherein the ball-material ratio is 5:1, the rotating speed is 200rpm, the argon atmosphere protection is adopted, the ball milling time is 8-48 h, and the ball milling mode is as follows: rotating positively for 10 min-standing for 10 min-rotating negatively for 10 min-standing for 10min, circulating in a cycle, ball-milling for 2h, and standing for 1 h; and after the high-energy ball milling is finished, cooling the ball milling tank for 8 hours at room temperature, and then taking powder in a glove box filled with argon.

As a further illustration of the present invention, the specific process of placing the composite mixed powder in a mold for compaction and then sintering is as follows:

and placing the composite material mixed powder into a graphite mould with graphite paper, placing the graphite mould on a prepress for prepressing and compacting, and then sintering by adopting a spark plasma sintering process.

As a further explanation of the invention, the pre-pressing pressure during the pre-pressing is 2-10 MPa, and the pre-pressing time is 1-15 min; the discharge plasma sintering process is carried out under the condition that the vacuum degree is less than 10^-2The sintering is carried out in a vacuum atmosphere of Pa, the sintering pressure is 30-40 Mpa, and the sintering temperature is 550-610 ℃; the sintering process is divided into two steps, the temperature is increased to 40 ℃ below the target sintering temperature at the temperature rise rate of 55 ℃/min, then the temperature is increased to the target sintering temperature at the temperature rise rate of 4 ℃/min, and the sintering time is shortenedIs 20-60 min.

As a further explanation of the invention, the preparation process of the aluminum liquid is as follows:

after the pure aluminum block is melted at the set temperature, oxide skin on the surface of the aluminum liquid is removed, and the completely melted aluminum liquid is exposed.

As a further explanation of the invention, the set temperature is 680-850 ℃; the dilution ratio is the mass ratio of the pure aluminum block to the composite material precursor, and the ratio is 1: 1-20: 1; and after the precursor is added, the preset time duration in the heat preservation stage is 5-60 min.

As a further explanation of the invention, the stirring treatment is ultrasonic vibration stirring or mechanical blade stirring, wherein the ultrasonic power is 10W-10 kW, the ultrasonic frequency is 10kHZ-30kHZ, the stirring speed of the blade stirring is 100-1000 rpm, and the stirring time is 10 s-12 min.

As a further explanation of the invention, the time of the heat preservation stage after the stirring treatment is 30 s-10 min.

As a further illustration of the invention, during the thermomechanical treatment: the heat preservation temperature is 300-550 ℃; the heat preservation time is 10-30 min; the extrusion ratio is 10: 1-33: 1; the extrusion speed is 1-10 mm/s.

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

1. according to the method for preparing the carbon nanotube reinforced aluminum-based composite material by the solid-liquid method, the carbon nanotube reinforced aluminum-based composite material is prepared by the preparation method combining the powder metallurgy method which is easy to obtain excellent performance and the casting method which is easy to produce in a large scale, large-scale and low-cost preparation of the carbon nanotube reinforced aluminum-based composite material is realized, and the problems that the carbon nanotube is easy to float and agglomerate in aluminum liquid, is difficult to wet, has serious reaction and the like are solved.

2. The carbon nano tube reinforced aluminum matrix composite prepared by the method obviously improves the strength of the material, and simultaneously retains the plasticity of the material to a great extent.

Drawings

FIG. 1 is a schematic view of a process flow for preparing a carbon nanotube reinforced aluminum matrix composite by a solid-liquid method according to the present invention;

FIG. 2 is a scanning electron microscope image of the morphology of the treated carbon nanotube-reinforced aluminum-based composite material in example 1 of the present invention;

FIG. 3 is a plot of the area distribution of the spectral carbon elements of the region of FIG. 2;

FIG. 4 is a Raman spectrum of the material treated in example 2 of the present invention;

FIG. 5 is a graph of the engineering stress strain for inventive example 1, example 2 and comparative materials.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a detailed description of the present invention will be given below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Fig. 1 is a schematic view of a process flow for preparing a carbon nanotube reinforced aluminum matrix composite by a solid-liquid method, and as shown in fig. 1, the invention provides a method for preparing a carbon nanotube reinforced aluminum matrix composite by a solid-liquid method, which comprises the following steps:

a method for preparing a carbon nano tube reinforced aluminum matrix composite material by a solid-liquid method comprises the following steps:

the method comprises the following steps: preparing composite material mixed powder: carrying out high-energy ball milling and mixing on aluminum powder, carbon nano tubes and a process control agent in a certain proportion to obtain composite material mixed powder;

in the first step of the invention, the aluminum powder is spherical pure aluminum powder of 15-53 um; the carbon nano tube is a multi-wall carbon nano tube with the tube diameter of 10-30 nm, and the mass fraction of the carbon nano tube is more than 0% and less than or equal to 10%; the process control agent is stearic acid, and the mass fraction of the process control agent is more than 0 percent and less than or equal to 5 percent;

the specific technological parameters of the high-energy ball milling process are as follows: planetary ball milling, a 500mL zirconia ball milling tank and 10mm zirconia balls, wherein the ball-material ratio is 1:5, the rotating speed is 200rpm, the argon atmosphere protection is adopted, the ball milling time is 8-48 h, and the ball milling mode is as follows: rotating positively for 10 min-standing for 10 min-rotating negatively for 10 min-standing for 10min, circulating in a cycle, ball-milling for 2h, and standing for 1 h; and after the high-energy ball milling is finished, cooling the ball milling tank for 8 hours at room temperature, and then taking powder in a glove box filled with argon.

The high-energy ball milling process in the first step of the invention can uniformly disperse the carbon nano tubes in the aluminum powder.

Step two: preparing a composite material precursor: placing the composite material mixed powder into a mold to be compacted, then sintering, and then taking out a composite material mixed powder sample when the composite material mixed powder is cooled to 40 ℃ along with a furnace to obtain a composite material precursor;

the specific process of placing the composite material mixed powder in a die for compaction and then sintering preferably adopts the following mode:

and placing the composite material mixed powder into a graphite mould with graphite paper, placing the graphite mould on a prepress for prepressing and compacting, and then sintering by adopting a spark plasma sintering process.

In the second step of the invention, the graphite mold preferably adopts a graphite mold with the inner diameter of 30-45 mm; the prepressing pressure is 2-10 MPa, and the prepressing time is 1-15 min; the discharge plasma sintering process is carried out under the condition that the vacuum degree is less than 10^{- 2}The sintering is carried out in a vacuum atmosphere of Pa, the sintering pressure is 30-40 Mpa, and the sintering temperature is 550-610 ℃; the sintering process is divided into two steps, the temperature is increased to 40 ℃ below the target sintering temperature at the temperature increase rate of 55 ℃/min, then the temperature is increased to the target sintering temperature at the temperature increase rate of 4 ℃/min, and the sintering time is 20-60 min.

In the second step of the invention, the composite material precursor with excellent performance can be obtained by proper sintering pressure, sintering temperature and sintering time.

Step three: preparing a composite material by a solid-liquid method: adding the composite material precursor into the completely molten aluminum liquid according to a certain dilution ratio, pressing the precursor into the aluminum liquid, and preserving heat for a preset time after the furnace body temperature reaches the set temperature again; then stirring for a certain period of time; preserving heat for a certain time after the temperature of the furnace body reaches the set temperature again, pouring the furnace body into a mold, and solidifying to obtain a carbon nano tube reinforced aluminum matrix composite ingot;

in the third step of the invention, the aluminum liquid is preferably prepared by adopting the following method:

after the pure aluminum block is melted at the set temperature, oxide skin on the surface of the aluminum liquid is removed, and the completely melted aluminum liquid is exposed.

In the third step of the invention, the set temperature is 680-850 ℃; the dilution ratio is the mass ratio of the pure aluminum block to the composite material precursor, and the ratio is 1: 1-20: 1; and after the precursor is added, the preset time duration in the heat preservation stage is 5-60 min.

In the third step of the invention, the stirring treatment is ultrasonic vibration stirring or mechanical blade stirring, wherein the ultrasonic power is 10W-10 kW, the stirring speed of the blade stirring is 100-1000 rpm, and the stirring time is 10 s-12 min; the time of the heat preservation stage after the stirring treatment is 30 s-10 min; the cast-in mold is a graphite mold with the model of 30-40 mm of inner diameter.

In the third step of the invention, the oxide skin on the surface of the aluminum liquid is removed firstly, and then the composite material precursor is added to prevent the oxide skin from being mixed into the metal liquid in the subsequent stirring to cause performance deterioration; secondly, pressing the composite material precursor into the aluminum liquid to prevent the precursor from being oxidized in a high-temperature environment; the final heat preservation after stirring is to float low-density impurities and play a certain impurity removal effect.

Step four: thermal mechanical treatment: preserving the heat of the carbon nano tube reinforced aluminum matrix composite ingot at a certain temperature for a certain time, and then carrying out hot extrusion at a certain extrusion ratio and extrusion speed to obtain a final carbon nano tube reinforced aluminum matrix composite;

in the fourth step of the invention, the heat preservation temperature is 300-550 ℃; the heat preservation time is 10-30 min; the extrusion ratio is 10: 1-33: 1; the extrusion speed is 1-10 mm/s.

The thermal mechanical treatment process in the fourth step of the invention is to improve the compactness of the carbon nanotube reinforced aluminum matrix composite casting and the dispersibility of the carbon nanotubes in the aluminum matrix, and improve the comprehensive performance of the composite.

The following is a detailed description of two preferred embodiments:

example 1:

the method comprises the following steps: preparing composite material mixed powder: placing 15-53 um spherical pure aluminum powder, 2% by mass of multi-walled carbon nanotubes with the pipe diameter of 10-30 nm and 1% by mass of stearic acid in a zirconia ball milling tank, adding 10mm zirconia grinding balls according to the ball-to-material ratio of 5:1, closing the cover, and introducing argon for 2 min; placing the pot in a ball mill, wherein the ball milling mode is planetary ball milling, the rotating speed is 200rpm, the ball milling time is 14h, the specific process is forward rotation for 10 min-standing for 10 min-reverse rotation for 10 min-standing for 10min, the process is a small-period cycle, and the ball milling is stopped for 1h and the ball milling pot is cooled after the ball milling accumulated time is 2 h; and after the ball milling is finished, cooling the ball milling tank for 8 hours, and then taking powder in a glove box filled with argon.

Step two: preparing a composite material precursor: placing the composite material mixed powder prepared in the step one in a graphite mould with graphite paper and a diameter of 45mm, and placing the graphite mould on a prepress for compaction, wherein the prepress is 6MPa, and the prepress time is 5 min; sintering the graphite mould filled with the composite material mixed powder after prepressing in a discharge plasma sintering furnace, wherein the sintering is carried out at the pressure of 10^-2The method is carried out in a vacuum atmosphere, firstly, a discharge plasma sintering furnace is heated to 550 ℃ at the heating rate of 55 ℃/min for 10min, then heated to 590 ℃ at the heating rate of 4 ℃/min for 10min, then the temperature is kept for 30min under the pressure of 30MPa, and finally, a sample is taken out when the temperature is cooled to 40 ℃ along with the furnace, so as to prepare the precursor of the composite material.

Step three: preparing a composite material by a solid-liquid method: melting a pure aluminum block at 750 ℃, removing oxide skin on the surface of the aluminum liquid, exposing the completely melted aluminum liquid, adding the precursor of the composite material prepared in the step two according to the dilution ratio of 3:1, pressing the precursor into the aluminum liquid, and preserving heat for 30min after the temperature of the furnace body reaches 750 ℃ again; then, mechanical stirring (a blade type stirring rod at 250rpm) is adopted for stirring treatment for 1 min; and (3) preserving the heat for 10min again after the temperature of the furnace body reaches 750 ℃ again, pouring the furnace body into a graphite mold with the inner diameter of 30mm, and solidifying to obtain the carbon nano tube reinforced aluminum matrix composite ingot.

Step four: thermal mechanical treatment: and (3) preserving the heat of the carbon nano tube reinforced aluminum matrix composite ingot obtained in the step three for 20min at 500 ℃, and then performing hot extrusion at an extrusion ratio of 18:1 and an extrusion speed of 3mm/s to obtain the final carbon nano tube reinforced aluminum matrix composite.

Fig. 2 is a scanning electron microscope image of the texture of the carbon nanotube-reinforced aluminum matrix composite processed in example 1, and fig. 3 is a surface distribution diagram of the energy spectrum carbon element corresponding to the electron microscope image of the texture of fig. 2, which can clearly observe that the carbon element is uniformly distributed on the aluminum matrix, that is, the carbon nanotubes are uniformly distributed in the aluminum matrix after the processing in this embodiment.

Example 2:

the method comprises the following steps: preparing composite material mixed powder: placing 15-53 um spherical pure aluminum powder, 2% by mass of multi-walled carbon nanotubes with the pipe diameter of 10-30 nm and 1% by mass of stearic acid in a zirconia ball milling tank, adding 10mm zirconia grinding balls according to the ball-to-material ratio of 5:1, closing the cover, and introducing argon for 2 min; placing the pot in a ball mill, wherein the ball milling mode is planetary ball milling, the rotating speed is 200rpm, the ball milling time is 14h, the specific process is forward rotation for 10 min-standing for 10 min-reverse rotation for 10 min-standing for 10min, the process is a small-period cycle, and the ball milling is stopped for 1h and the ball milling pot is cooled after the ball milling accumulated time is 2 h; and after the ball milling is finished, cooling the ball milling tank for 8 hours, and then taking powder in a glove box filled with argon.

Step two: preparing a composite material precursor: placing the composite material mixed powder prepared in the step one in a graphite mould with graphite paper and a diameter of 45mm, and placing the graphite mould on a prepress for compaction, wherein the prepress is 6MPa, and the prepress time is 5 min; sintering the graphite mould filled with the composite material mixed powder after prepressing in a discharge plasma sintering furnaceWherein the sintering is carried out at a pressure of 10^-2The method is carried out in a vacuum atmosphere, firstly, a discharge plasma sintering furnace is heated to 550 ℃ at the heating rate of 55 ℃/min for 10min, then heated to 590 ℃ at the heating rate of 4 ℃/min for 10min, then the temperature is kept for 30min under the pressure of 30MPa, and finally, a sample is taken out when the temperature is cooled to 40 ℃ along with the furnace, so as to prepare the precursor of the composite material.

Step three: preparing a composite material by a solid-liquid method: melting a pure aluminum block at 800 ℃, removing oxide skin on the surface of the aluminum liquid, exposing the completely melted aluminum liquid, adding the precursor of the composite material prepared in the step two in a dilution ratio of 6:1, pressing the precursor into the aluminum liquid, and preserving heat for 30min after the temperature of the furnace body reaches 800 ℃ again; then, mechanical stirring (a blade type stirring rod at 650rpm) is adopted for stirring treatment for 1 min; and (3) preserving the heat for 10min again after the temperature of the furnace body reaches 800 ℃ again, pouring the furnace body into a graphite mold with the inner diameter of 30mm, and solidifying to obtain the carbon nano tube reinforced aluminum matrix composite ingot.

Step four: thermal mechanical treatment: and (3) preserving the heat of the carbon nano tube reinforced aluminum matrix composite ingot obtained in the step three for 20min at 500 ℃, and then performing hot extrusion at an extrusion ratio of 18:1 and an extrusion speed of 3mm/s to obtain the final carbon nano tube reinforced aluminum matrix composite.

FIG. 4 is the Raman spectrum of the carbon nanotube-reinforced aluminum-based composite material treated in example 2 at 1340cm^-1And 1570cm^-1The obvious characteristic peak of the carbon nano tube can be seen at the position of (2), which indicates that the carbon nano tube which is not completely reacted still exists after the treatment of the example 2.

Table 1 shows the comparison of mechanical properties of pure aluminum, which is a comparative material treated in the same manner as the carbon nanotube aluminum-based composite material treated by the method for preparing a carbon nanotube-reinforced aluminum-based composite material by a solid-liquid method according to the present invention, and fig. 5 is a graph showing engineering stress-strain curves of example 1 and example 2 of the present invention and the comparative material. The same procedure as in example 1 was repeated except that the dilution ratio was 1:0, i.e., no composite precursor was added. According to table 1 and fig. 5, it can be shown that after the treatment process of the present invention, not only the problem of difficulty in realizing large-size and large-scale production is solved, but also the problems of floating agglomeration and difficulty in being wetted of the carbon nanotubes in the aluminum liquid are solved by using the precursor method, the problem of severe reaction of the carbon nanotubes in the aluminum liquid is controlled by controlling the casting temperature and the heat preservation time, and the finally obtained material has significantly improved strength compared with a comparative material, and simultaneously, the plasticity of the material is retained to a great extent.

Table 1 mechanical property data of examples 1 and 2 and comparative materials before and after the inventive treatment

Treatment method	Tensile strength/MPa	Yield strength/MPa	Elongation/percent
				Example 1	118.17	89.87	21.14
Example 2	156.02	130.81	22.38
				Contrast material	74.39	60.15	28.81

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.