A method for preparing a high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite

Abstract

The application discloses a preparation method of a high-strength high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material. A mixed acid solution is used for surface modification of CNTs, impurities (such as amorphous carbon) in the original CNTs can be corroded, and functional groups (such as hydroxyl and carboxyl) can be grafted on the surface of the CNTs, so that the dispersibility of the CNTs is preferably improved. Subsequently, an optimal ball milling process is adopted to overcome the agglomeration phenomenon of the high-volume-fraction carbon nanotubes, high-volume-fraction CNTs composite powder with good dispersion is obtained, then, a low-density high-strength high-toughness CNTs / Al composite material with a carbon nanophase content of 5 vol.% is prepared by using a discharge plasma sintering method, high-efficiency stable combination of an Al-C interface is realized, the strengthening effect of the high-volume-fraction carbon nanotubes is fully exerted, the problems of agglomeration entanglement and uneven dispersion caused by the high-volume-fraction carbon nanotubes are avoided, and the reinforcing effect of the carbon nanotubes is fully exerted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum matrix composites, and specifically discloses a preparation method of high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite. BACKGROUND

[0002] Aluminum and its alloys have excellent properties such as light weight, corrosion resistance, and good thermal and electrical conductivity, and have become key materials in national major fields such as aerospace and transportation. Aluminum matrix composites have the advantages of high strength, light weight, and easy manufacturing, and have been widely used in aerospace, automobiles, ships, and military industries. However, in actual application scenarios, aluminum matrix composites still face great challenges, and the interface bonding between the reinforcement and the aluminum matrix and its dispersion in the aluminum matrix become the key to restricting the application of aluminum matrix composites. In the past few decades, researchers have added various ceramic particles and carbon materials to improve the mechanical properties of aluminum matrix composites. Carbon nanotubes are a promising carbon-based reinforcing material with special sp2 hybridization of carbon atoms in its structure, low density, high specific surface area, large aspect ratio, excellent electrical and thermal conductivity, and ultra-high tensile strength and elastic modulus, making it an ideal reinforcing material for metal matrix composites, and has attracted widespread attention from domestic and foreign scholars. Because the tensile strength, Young's modulus, thermal conductivity, wear resistance, and other physical and chemical properties of the composite are positively correlated with the volume fraction of the reinforcing material, high-volume-fraction addition has attracted the attention of researchers. However, carbon nanotubes have a large specific surface area and high specific surface energy, and are prone to agglomeration under the action of van der Waals force, and only a very limited number of methods can add more than 5vol.% CNTs to the aluminum matrix while maintaining good dispersion, thereby significantly improving the comprehensive mechanical properties of aluminum matrix composites. Current research on CNTs / Al composites is mostly limited to lower volume fractions of carbon nanotube addition, so developing high-volume-fraction carbon nanotubes as reinforcing materials and improving the strengthening efficiency per unit volume is expected to achieve a major breakthrough in low-density high-performance CNTs / Al composites.

[0003] To overcome the above challenges, people have developed a variety of technologies, such as in-situ growth method, molecular level mixing process, electrostatic adsorption, etc., but most of them are complex process and high cost for industrial application. There are also solution mixing to study the dispersion of carbon nanotubes, including ultrasonic dispersion, mechanical stirring, etc. In addition, it is also an effective way to obtain uniform carbon nanotube dispersion by surfactant adsorption or chemical oxidation modification of carbon nanotube surface. Compared with the above technologies, ball milling has become a widely selected method for preparing carbon nanotube reinforced metal matrix composites due to its simple operation and wide application. The present application adopts surface modification with little damage to carbon nanotubes and ball milling, which can effectively inhibit the agglomeration of carbon nanotubes at high volume fraction, obtain carbon nanotube dispersion uniform composite powder, and is beneficial to subsequent SPS sintering to prepare high strength and toughness high volume fraction carbon nanotube reinforced aluminum matrix composite, play the role of high volume fraction carbon nanotube reinforcement in the matrix, and improve the mechanical properties. SUMMARY

[0004] The purpose of the present application is to obtain high strength and toughness high volume fraction carbon nanotube reinforced aluminum matrix composite. First, the carbon nanotubes are surface modified, and then the modified carbon nanotubes and aluminum powder are mixed by high-energy dry ball milling to obtain CNTs / Al composite powder with uniform dispersion of carbon nanotubes, and high strength and toughness high volume fraction carbon nanotube reinforced aluminum matrix composite is prepared by spark plasma sintering. The method is simple in operation, short in process flow and strong in popularization.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of high strength and toughness high volume fraction carbon nanotube reinforced aluminum matrix composite comprises the following steps:

[0007] (1) Surface modification treatment of carbon nanotubes: 0.3-0.5g of carbon nanotubes is added to 160-200ml mixed acid solution (concentrated sulfuric acid: concentrated nitric acid = 3:1, volume ratio), and ultrasonic (power 300-400W) assisted treatment for 3-4h, then suction filtration, washing and vacuum drying;

[0008] (2) High-energy dry ball milling: the modified carbon nanotubes obtained in step (1), pure aluminum powder and process control agent (stearic acid) are added to the ball milling tank, and the process is completed in a glove box under Ar gas protection atmosphere. In order to avoid high temperature in the tank during ball milling, intermittent ball milling method is adopted, and forward and reverse rotation is alternately operated, each running for 15-20min and pausing for 15min. The diameters of the large and small steel balls are 5mm and 3mm respectively, and the mass ratio of the large and small steel balls is 1:1; the ball-to-material mass ratio is 10:1-15:1, the ball milling speed is 300-400rpm, the ball milling time is 8-10h, and the stearic acid addition amount is 1-1.5wt.% of the total amount of modified carbon nanotubes and pure aluminum powder.

[0009] (3) Removal of process control agent: the composite powder after step (2) ball milling is taken out in the glove box, and calcined at 300-400 DEG C for 2-3h to remove stearic acid in the composite powder, to obtain CNTs / Al composite powder.

[0010] (4) Preparation of high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite: the CNTs / Al composite powder prepared in step (3) is put into a graphite mold, pre-pressed at a pressure of 10-20 MPa for 5-10 min, and then sintered and solidified in a spark plasma sintering system, the sintering temperature is 620 DEG C, the heating rate is 80-100 DEG C / min, the sintering pressure is 30-40 MPa, the sintering holding time is 30-40 min, and the furnace is cooled to obtain a high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite.

[0011] Preferably, the volume ratio of modified carbon nanotubes and pure aluminum powder in step (2) is 5:95.

[0012] The present application has the following advantages:

[0013] (1) In the case of less damage to the structure of carbon nanotubes, the surface modified carbon nanotubes can effectively avoid agglomeration, enhance the dispersibility of carbon nanotubes, and improve the wetting ability of carbon nanotubes. The present application uses a mixed acid solution prepared by mixing concentrated sulfuric acid and concentrated nitric acid to modify the surface of carbon nanotubes. The mixed acid solution can remove CNTs impurities (such as amorphous carbon) and graft functional groups (such as hydroxyl and carboxyl) on the surface of CNTs, which can better improve the dispersibility of CNTs and prevent carbon nanotube agglomeration.

[0014] (2) In the ball milling process, the use of smaller diameter steel balls and appropriate amount of stearic acid as medium can reduce the damage and destruction of CNTs and reduce cold welding, and the use of higher speed and longer ball milling time can ensure the dispersion of high volume fraction CNTs. After long time and high speed ball milling of pure aluminum powder, the aluminum powder is flattened into a sheet shape, the surface area is increased, the adsorption capacity of carbon nanotubes is enhanced, the compatibility of high volume fraction carbon nanotubes and sheet-shaped pure aluminum powder is good, the carbon nanotubes are dispersed on the surface of the sheet-shaped pure aluminum powder, and the cold welding phenomenon of the aluminum powder layer also exists, most of the carbon nanotubes will be embedded between the layers of the aluminum powder, which can form a good bonding state with the matrix, which is conducive to the subsequent preparation of high volume fraction carbon nanotube reinforced aluminum matrix composite with good interface bonding, which can play the enhancement advantage of high volume fraction carbon nanotube and significantly improve the mechanical properties of CNTs / Al composite material.

[0015] (3) The method for preparing high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite of the present application has the advantages of simple operation, short process flow, low equipment requirement, low cost and good popularization. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Process flow chart for preparing high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material of the present application;

[0017] Figure 2 SEM surface morphology chart for preparing high-volume-fraction GNTs / Al composite powder of the present application;

[0018] Figure 3 Room temperature tensile stress-strain curve chart for pure Al and high-volume-fraction CNTs / Al composite material;

[0019] Figure 4 Fracture morphology chart for high-volume-fraction CNTs / Al composite material;

[0020] Figure 5 Interface micro-area TEM morphology chart for preparing high-strength and high-toughness high-volume-fraction CNTs / Al composite material of the present application. DETAILED DESCRIPTION

[0021] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.

[0022] Example 1

[0023] A preparation method of high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material, comprising the following steps:

[0024] (1) Surface modification treatment of carbon nanotubes: 0.33 g of original carbon nanotubes is added to 200 ml of mixed acid solution (analytically pure concentrated sulfuric acid: analytically pure concentrated nitric acid = 3:1, volume ratio), and ultrasonic assisted treatment is performed for 4 h, followed by suction filtration, washing, and vacuum drying;

[0025] (2) High-energy dry ball milling mixing: the modified carbon nanotubes in step (1), 9.67 g of pure aluminum powder, and 0.1 g of process control agent (stearic acid) are added to a ball milling tank, and the process is completed in a glove box Ar gas protection atmosphere. In order to avoid excessive temperature in the tank during ball milling, intermittent ball milling method is adopted, and forward and reverse rotation is alternately operated, with 15 min pause for each 15 min operation. The diameters of the steel balls are 5 mm and 3 mm respectively, the ball-to-material mass ratio is 10:1, the ball milling speed is 400 rpm, and the ball milling time is 10 h.

[0026] (3) Removal of process control agent: the composite powder after ball milling in step (2) is taken out in the glove box, and calcined at 400℃ for 2 h to remove stearic acid in the composite powder, and CNTs / Al composite powder is obtained.

[0027] (4) High-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material preparation: the CNTs / Al composite powder prepared in step (3) is placed into a graphite mold, pre-pressed for 10 min under a pressure of 20 MPa, and then sintered and solidified in a discharge plasma sintering system, with a sintering temperature of 620 DEG C, a heating rate of 100 DEG C / min, a sintering pressure of 40 MPa, and a sintering holding time of 40 min, and the high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material is prepared by furnace cooling.

[0028] (5) Mechanical property test: the CNTs / Al composite material prepared in step (4) is cut into dog bone-shaped tensile pieces with a gauge length of 6 mm, a width of 2 mm, and a thickness of 1 mm, and the room temperature tensile properties are tested at room temperature by using a universal testing machine, the mechanical properties are analyzed by stress-strain curves, and the fracture morphology is observed by using a scanning electron microscope.

[0029] The process flow chart of the high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material prepared in the application is shown in Figure 1 .

[0030] Figure 2 The SEM surface morphology of the CNTs / Al composite powder prepared in the application is shown in Figure 2 Figs. (a)-(c) are SEM surface morphology diagrams of the GNTs / Al composite powder at different magnifications, as shown in Figure 2 Fig. (a), the spherical original Al powder is flattened into a flaky shape after long-time high-speed ball milling, with a thickness of 1-3 μm, Figure 2 Fig. (b) shows that no carbon nanotube clusters are found, indicating that the carbon nanotubes are uniformly distributed on the surface of the flaky Al powder without obvious agglomeration, Figure 2 Fig. (b) is further enlarged, as shown in Figure 2 Fig. (c), a small part of the carbon nanotubes are exposed (as indicated by the arrows), and most of the carbon nanotubes are covered under the cold-welded stacked aluminum flakes, thereby inhibiting further damage of the carbon nanotubes by ball milling.

[0031] Comparative Example 1

[0032] A preparation method of a high-volume-fraction carbon nanotube reinforced aluminum matrix composite material, comprising the following steps:

[0033] (1) Surface modification treatment of carbon nanotubes: 0.33 g of original carbon nanotubes is added into 200 ml of mixed acid solution (analytically pure concentrated sulfuric acid: analytically pure concentrated nitric acid = 3:1, by volume), and ultrasonic auxiliary treatment is performed for 4 h, followed by suction filtration, washing, and vacuum drying;

[0034] (2) High-energy ball milling mixing: 9.67 g of pure aluminum powder and 200 ml of ethanol were added to a ball milling tank (this process was completed in a glove box under Ar gas protection atmosphere) for pre-ball milling, the ball milling speed was 400 rpm, the ball milling time was 4 h, and after the end, it was dried by suction filtration. Then the modified carbon nanotubes in step (1), 9.67 g of pre-ball milled pure aluminum powder and 0.1 g of process control agent (stearic acid) were added to the ball milling tank (this process was completed in a glove box under Ar gas protection atmosphere), the ball milling speed was 400 rpm, and the ball milling time was 6 h. In order to avoid the temperature in the tank being too high during ball milling, the intermittent ball milling method was used, and the forward and reverse rotation was alternately operated, and each operation was 15 min and the pause was 15 min. The diameters of the ball milling steel balls were 5 mm and 3 mm respectively, and the ball-to-material mass ratio was 10:1.

[0035] (3) Removal of process control agent: the composite powder after ball milling in step (2) was taken out in the glove box, calcined at 400℃ for 2 h to remove stearic acid in the composite powder, and CNTs / Al composite powder was obtained.

[0036] (4) Preparation of high volume fraction carbon nanotube reinforced aluminum matrix composite material: the CNTs / Al composite powder prepared in step (3) was put into a graphite mold, pre-pressed for 10 min under a pressure of 20 MPa, and then sintered and solidified in a spark plasma sintering system, the sintering temperature was 620℃, the heating rate was 100℃ / min, the sintering pressure was 40 MPa, the sintering holding time was 40 min, and the furnace was cooled down, and a high volume fraction carbon nanotube reinforced aluminum matrix composite material was prepared.

[0037] (5) Mechanical property test: the CNTs / Al composite material prepared in step (4) was cut into dog bone-shaped tensile pieces with a gauge length of 6 mm, a width of 2 mm and a thickness of 1 mm, and the room temperature tensile properties were tested at room temperature by using a universal testing machine, the mechanical properties were analyzed by stress-strain curve, and the fracture morphology was observed by scanning electron microscope.

[0038] Comparative example 2

[0039] A preparation method of a high volume fraction carbon nanotube reinforced aluminum matrix composite material, comprising the following steps:

[0040] (1) Surface modification treatment of carbon nanotubes: 0.33 g of original carbon nanotubes was added to 200 ml of mixed acid solution (analytical pure concentrated sulfuric acid: analytical pure concentrated nitric acid = 3:1, by volume), and ultrasonic assisted treatment was carried out for 4 h, and then suction filtration, washing and vacuum drying were carried out.

[0041] (2) High-energy ball milling: The modified carbon nanotubes from step (1), 9.67 g of pure aluminum powder, and 0.1 g of a process control agent (stearic acid) were added to a ball mill. This process was completed in an Ar gas protective atmosphere in a glove box. To avoid excessive temperature in the mill, an intermittent ball milling method was used, with alternating forward and reverse rotations and a 15-minute pause every 15 minutes. The diameters of the large and small steel balls for the ball mill were 5 mm and 3 mm, respectively. The ball-to-material mass ratio was 10:1. The ball milling speed was 400 rpm, and the ball milling time was 10 h.

[0042] (3) Removal of process control agent: The composite powder after ball milling in step (2) was taken out of the glove box and calcined at 400°C for 2h to remove the stearic acid in the composite powder to obtain CNTs / Al composite powder.

[0043] (4) Preparation of high volume fraction carbon nanotube reinforced aluminum matrix composite material: The CNTs / Al composite powder prepared in step (3) was placed in a graphite mold, pre-pressed at a pressure of 20 MPa for 10 min, and then sintered and solidified in a spark plasma sintering system at a sintering temperature of 600 °C, a heating rate of 100 °C / min, a sintering pressure of 40 MPa, a sintering holding time of 40 min, and cooled in the furnace to obtain a high volume fraction carbon nanotube reinforced aluminum matrix composite material.

[0044] (5) Mechanical property test: The CNTs / Al composite material prepared in step (4) was cut into dog-bone-shaped tensile sheets with a gauge length of 6 mm, a width of 2 mm, and a thickness of 1 mm. The room temperature tensile properties were tested using a universal testing machine at room temperature. The mechanical properties were analyzed by stress-strain curves, and the fracture morphology was observed using a scanning electron microscope.

[0045] Figure 3 The figure shows the room temperature tensile stress-strain curves of pure Al and high volume fraction CNTs / Al composite materials. It can be seen from the figure that the ultimate tensile strength and yield strength of Example 1 are significantly improved compared with pure Al, Comparative Example 1 and Comparative Example 2. Figure 4 The fracture morphology of high volume fraction CNTs / Al composite material is shown in Figure 2. Figure 4 In (a), it can be seen that there are serious hole defects in Comparative Example 1, and most of them are deep holes with large diameters, which lead to local early failure of the composite material and thus low strength. Figure 4 In (b), the pull-out phenomenon of a single carbon nanotube in Comparative Example 2 can be clearly seen, indicating the occurrence of interfacial debonding. Figure 4It can be seen from the middle (c) that the CNTs agglomeration phenomenon is not seen in the embodiment 1, and the obvious pulling-out phenomenon is not obvious, but a nanometer scale needle-shaped short rod is observed to be dispersedly distributed in the dimple, because part of the CNTs is reacted with Al at a high temperature, and the in-situ generated nanometer scale needle-shaped Al4C3 is uniformly distributed, thereby playing a second phase dispersion strengthening effect. Therefore, the yield strength and tensile strength of the CNTs / Al composite material prepared by the method of the application are obviously improved compared with the aluminum matrix, and the highest can be improved by 85%, and the plasticity is still good.

[0046] Table 1 Sintering temperature, tensile strength, elongation at break and hardness of sintered samples

[0047]

[0048] Figure 5 The interface micro-area TEM morphology of the high-strength and high-toughness high-volume-fraction CNTs / Al composite material prepared in the embodiment 1 of the application is shown in the figure. Figure 5 It can be seen from the middle (a) that a large number of dislocations are accumulated in the Al matrix, which seriously hinders the dislocation movement and the grain boundary slip, thereby significantly improving the mechanical strength of the composite material. There are many reasons for the dislocation accumulation, one is that the introduction of high-volume-fraction carbon nanotubes can be regarded as the form of second phase particles to hinder the movement of dislocations. Because the carbon nanotubes have extremely high elastic modulus and strength, the dislocation movement cannot cut through but only bypasses, resulting in the increase of dislocation density around the CNTs. Two is that Al and CNTs are two heterogeneous materials, and the thermal expansion coefficients are quite different, and a large thermal mismatch stress is easily generated at the Al-C interface, so that the matrix with low strength relaxes part of the thermal mismatch stress in the form of yield deformation, thereby causing high dislocation density near the interface between the Al matrix and the reinforcing phase. Figure 5 It can be seen from (b) and (c) that a small amount of single carbon nanotubes are embedded in the Al matrix to form a good interface bonding. But mainly a large number of nanometer short rods are dispersedly distributed in the Al matrix, because the size is below 100 nm and in a uniform dispersed state, so a good dispersion strengthening effect is achieved. Further magnification observation, Figure 5 The high-resolution transmission electron microscopy image of the middle (d) shows the lattice fringes of the phase, and the calculation shows that the interplanar spacing is 0.83 nm, which corresponds to the (003) crystal plane of Al4C3. The main reason for the formation of Al4C3 is that the CNTs introduce certain defects after being etched by concentrated acid, and the damage degree is further increased by the high-energy ball milling process, and finally the damaged CNTs are easily reacted with the Al matrix at a high sintering temperature by SPS, thereby generating Al4C3. In addition, in the middle (e), the selected area electron diffraction pattern of the phase is shown, and the diffraction spots are arranged in a circular ring, which is the characteristic of the polycrystalline structure. Figure 5It can also be seen in (d) that Al4C3 has a close interface with the Al matrix, which indicates that the interface bonding strength is high, and the interface bonding mode is reaction bonding. In summary, the high volume fraction carbon nanotubes are uniformly dispersed in the composite material, and form a good mechanical bond by embedding into the aluminum matrix, which is conducive to exerting its good load bearing capacity. In addition, due to the high sintering temperature, the interface reaction degree is relatively strong, and most of the CNTs have interface reaction with the Al matrix, but the nanoscale Al4C3 generated in situ is dispersedly distributed in the Al matrix, which solves the problem of poor Al-C interface wettability, further improves the interface bonding capacity, increases the critical stress required for interface debonding, and thus shows a large increase in the strength of the composite material. Therefore, the high-strength and high-toughness high volume fraction carbon nanotube reinforced aluminum matrix composite material prepared by the present application has great potential application value in parts such as automobile chassis, steering knuckles, engine cylinders, etc. which have high requirements for strength and stiffness.

[0049] It should be noted that although the present application only selects the composite material prepared by spark plasma sintering for testing, the present application can also be used for other composite material preparation methods (such as hot-pressing sintering, etc.), and the application of the present application is not limited to pure aluminum, and the similar effects can also be achieved by replacing the matrix powder (such as 6061 aluminum alloy powder, 7075 aluminum alloy powder), as long as appropriate adjustment and flexible application are made within the process parameter range disclosed in the present application.

[0050] Finally, it should be noted that although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art should understand that the technical solutions of the present application can be changed, modified or equivalently replaced without departing from the purpose and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing a high-strength, high-toughness, high-volume-fraction carbon nanotube-reinforced aluminum-based composite material, characterized in that: The method comprises the following steps: (1) surface modification treatment of carbon nanotubes: carbon nanotubes are added into a mixed acid solution, and are treated by ultrasonic assistance for 3-4 hours, and then are subjected to suction filtration, washing and vacuum drying; (2) high-energy dry ball milling mixing: the modified carbon nanotubes, pure aluminum powder and process control agent stearic acid obtained in step (1) are added into a ball milling tank, and the process is completed in a glove box under Ar gas protection atmosphere, in order to avoid high temperature in the tank during ball milling, an intermittent ball milling method is adopted, and positive and reverse rotation is alternately operated, and each operation is stopped for 15 minutes after being operated for 15-20 minutes; (3) removal of the process control agent: the composite powder after ball milling in step (2) is taken out in the glove box, and is calcined at 300-400 DEG C for 2-3 hours, so that the stearic acid in the composite powder is removed, and CNTs / Al composite powder is obtained; (4) preparation of high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material: the CNTs / Al composite powder prepared in step (3) is placed into a graphite mold, is pre-pressed under a pressure of 10-20 MPa for 5-10 minutes, and then is subjected to sintering and solidification in a spark plasma sintering system; The mass of the carbon nanotubes in step (1) is 0.3-0.5 g, the volume of the mixed acid solution is 160-200 ml, and the ultrasonic dispersion power is 300-400 W and the temperature is 25-35 DEG C; The mixed acid solution in step (1) is mixed by concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1-4:1; In step (2), the ball milling steel balls have two sizes, and the diameters of the large and small steel balls are 5 mm and 3 mm respectively, the ball-to-material mass ratio is 10:1-15:1, the ball milling speed is 300-400 rpm, the ball milling time is 8-10 hours, and the addition amount of stearic acid is 1-1.5 wt.% of the total amount of the modified carbon nanotubes and the pure aluminum powder; In step (2), the volume ratio of the modified carbon nanotubes to the pure aluminum powder is 5:95; In step (4), the spark plasma sintering temperature is 620 DEG C, the heating rate is 80-100 DEG C / min, the sintering pressure is 30-40 MPa, the sintering holding time is 30-40 min, and the high-strength and high-toughness high-volume-fraction carbon nanotube reinforced aluminum matrix composite material is prepared by furnace cooling.

2. The high strength and toughness high volume fraction carbon nanotube reinforced aluminum matrix composite material prepared by the method of claim 1, characterized in that: The content of the carbon nanotube phase reaches 5 vol.%.

Images