A method for preparing a nano-reinforcement assisted graphene reinforced aluminum matrix composite

Abstract

The application discloses a preparation method of a nano-reinforcement assisted graphene reinforced aluminum matrix composite material and relates to a preparation method of a graphene reinforced aluminum matrix composite material. In order to solve the problems of poor dispersing effect of graphene in the aluminum matrix composite material and mismatch between the strength of the matrix and the strength of the graphene, the application introduces nanoparticles to break, thin and disperse the graphene in the ball milling process, so that the dispersing of the graphene in the matrix is assisted, the nanoparticles are introduced into the matrix grains to play a dispersion strengthening role in the matrix, the strength of the matrix is enhanced, the strength of the matrix matches the strength of the graphene, and better effects are achieved in load transmission. The application realizes the cooperation of zero-dimensional and two-dimensional and variable and rigid reinforcements, achieves a synergistic effect, and has the advantages of simple preparation process, controllable parameters, low cost, excellent performance and the like, and realizes a breakthrough compared with the current graphene / aluminum preparation process.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of graphene reinforced aluminum matrix composite. BACKGROUND

[0002] Graphene is a kind of nanomaterial with high theoretical strength and elastic modulus. According to the composite strengthening theory, a small amount of graphene added in the matrix can obtain good strengthening effect. However, research in recent years shows that the strengthening effect of single graphene is limited, and the strength limit of graphene reinforced metal matrix composite has reached a certain bottleneck.

[0003] Due to the high dispersion difficulty of graphene as a nanomaterial, the high surface energy is easy to cause agglomeration and pores. In order to disperse graphene uniformly, high-energy ball milling and other methods are generally used, which is easy to cause the increase of graphene defects, the decrease of intrinsic strength, and also easy to cause the reaction of graphene to generate Al4C3. On the other hand, many researchers focus on the interface between graphene and aluminum, hoping to obtain a strong enough interface to obtain sufficient interface load transfer effect. Graphene is generally used in a low volume fraction, and is generally dispersed in the grain boundary, which is difficult to disperse completely to all parts of the matrix. Even if the strong interface bonding graphene is prepared, it can only play a role in a certain area. When the load is transferred to the matrix, microcracks will also tend to occur in the un-strengthened matrix, thereby bypassing the graphene and finally producing macrocracks. Therefore, it is necessary to match the interface strength of graphene and the matrix strength to achieve the best strengthening effect. At present, in order to improve the strength of the matrix, the method of matrix alloying is generally used, but the introduction of graphene always causes the segregation of alloying elements, changes the reaction behavior, and causes the problems of unsatisfactory strengthening effect and even performance degradation.

[0004] Therefore, it is urgent to find a hybrid composite design that can improve the dispersion effect of graphene, improve the strength of the matrix, and has a synergistic strengthening effect, so as to realize the preparation of nanoreinforced graphene aluminum composite. SUMMARY

[0005] In order to solve the problems of poor dispersion effect of graphene in aluminum matrix composite and mismatch between the strength of the matrix and the strength of graphene, the present application provides a preparation method of nanoreinforced graphene reinforced aluminum matrix composite.

[0006] The preparation method of nanoreinforced graphene reinforced aluminum matrix composite of the present application is carried out according to the following steps:

[0007] I. Powder component selection

[0008] Weigh 0.1–4 wt.% graphene, 1–10 wt.% nanoscale hard reinforcement, 0.5–3 wt.% control agent, and the balance aluminum metal powder as raw materials; weigh aluminum metal bulk, with the weight ratio of aluminum metal bulk to aluminum metal powder being (3–10):1; the aluminum metal powder and aluminum metal bulk are made of the same material; the control agent is stearic acid;

[0009] II. Dispersion Process

[0010] Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene, causing it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling also causes the aluminum powder to continuously cold weld and break down, allowing the nanoscale hard reinforcement to penetrate into the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder. The control agent plays a role in regulating the ball milling energy.

[0011] III. Preforming of Pre-formed Powder

[0012] The composite pre-powder is loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the mold is placed in a heating furnace, filled with nitrogen, and heated at 600℃ to allow the control agent to fully react and volatilize.

[0013] IV. Aluminum Metal Impregnation

[0014] Place the aluminum metal block weighed in step one into the graphite mold at the bottom of the infiltration furnace chamber. Place the graphene-nanoscale hard reinforcement-aluminum preform obtained in step three into the upper part of the infiltration furnace chamber. Heat the vacuum infiltration furnace and heat the preform to 560-650℃ at 3-10℃ / min, and hold for 0.5-3h. Heat the aluminum metal block weighed in step one to 780-880℃ and hold for 0.5-2h to obtain molten aluminum metal. Immerse the preheated graphene-nanoscale hard reinforcement-aluminum preform into the molten aluminum metal and stop heating. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained.

[0015] V. Large Plastic Deformation Treatment and Composition Homogenization

[0016] The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

[0017] Principles and beneficial effects of this invention:

[0018] 1. This invention introduces a second type of hard nano-reinforcement during the ball milling process of graphene and aluminum powder. This nano-sized grinding ball continuously collides with the graphene sheet during the milling process, achieving a level of effect far exceeding that of conventional millimeter-sized grinding balls in terms of breaking, thinning, and dispersing graphene. This results in high-quality dispersion of graphene and improves the strengthening efficiency of graphene.

[0019] 2. The nanoscale hard reinforcement introduced in this invention can enhance the friction between the grinding ball and the aluminum powder, increasing the grinding energy. While conventional powder metallurgy methods aim to disperse the reinforcement on the surface of the aluminum powder, this invention, due to its higher grinding energy, allows for a continuous cycle of cold welding and crushing of the aluminum powder. This facilitates the penetration of graphene and the nanoscale hard reinforcement into the interior of the aluminum powder and even into the aluminum grains, increasing the dispersible range of the reinforcement and significantly improving the dispersion effect.

[0020] 3. This invention introduces a hard nano-reinforcement into the matrix grains, providing additional second-phase reinforcement within the matrix. When dislocations encounter graphene during slip, the layered structure of graphene makes them easily absorbed. However, when encountering the hard nano-reinforcement, they can only slip through a bypass mechanism. Therefore, the introduction of the hard nano-reinforcement in this invention increases the dislocation density of the matrix and improves the work hardening rate.

[0021] 4. This invention suppresses grain growth during heat treatment by introducing nano-hard reinforcements. Typically, when the solution treatment temperature of a heat-treatable aluminum alloy exceeds 500°C, grains grow rapidly at this temperature. This invention introduces additional nano-reinforcements to pin grain boundaries, suppressing grain growth and achieving a stronger fine-grain strengthening effect.

[0022] 5. In the composite material prepared by this invention, the defects of graphene are controllable and it does not react with aluminum. Through the control of the ball milling process, excessive defects are not introduced, and the graphene structure remains intact, making it difficult to react with aluminum to form harmful intermetallic compounds, thus achieving a high-quality composite of graphene and aluminum. The excellent interface and stronger matrix further enhance the load transfer effect.

[0023] 6. The nano-reinforcement-assisted graphene-reinforced aluminum matrix composite material prepared by this invention achieves the combination of zero-dimensional and two-dimensional, variable and rigid reinforcements. The zero-dimensional rigid reinforcement promotes dislocation multiplication during deformation, while the two-dimensional variable graphene absorbs dislocations and coordinates matrix deformation, thereby achieving a comprehensive improvement in strength and plasticity and obtaining a synergistic effect. Furthermore, the preparation process is simple, the parameters are controllable, the cost is low, and the performance is excellent, representing a breakthrough compared to current graphene / aluminum preparation processes. Attached Figure Description

[0024] Figure 1 The image shows a micrograph of the composite material pre-powder obtained in Example 1.

[0025] Figure 2 Raman image of the nano-reinforced graphene-reinforced aluminum matrix composite material obtained in Example 1;

[0026] Figure 3 The image shows the metallographic microstructure of the nano-reinforced graphene-reinforced aluminum matrix composite material obtained in Example 1. Detailed Implementation

[0027] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0028] Specific Implementation Method 1: The preparation method of the nano-reinforced graphene-reinforced aluminum matrix composite material in this implementation method is carried out according to the following steps:

[0029] I. Selection of Powder Components

[0030] Weigh 0.1–4 wt.% graphene, 1–10 wt.% nanoscale hard reinforcement, 0.5–3 wt.% control agent, and the balance aluminum metal powder as raw materials; weigh aluminum metal bulk, with the weight ratio of aluminum metal bulk to aluminum metal powder being (3–10):1; the aluminum metal powder and aluminum metal bulk are made of the same material; the control agent is stearic acid;

[0031] II. Dispersion Process

[0032] Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling in sequence. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene and cause it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling can also continuously cold weld and break down the aluminum powder, thereby allowing the nanoscale hard reinforcement to enter the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder.

[0033] III. Preforming of Pre-formed Powder

[0034] The composite pre-powder is loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the mold is placed in a heating furnace, filled with nitrogen, and heated at 600℃ to allow the control agent to fully react and volatilize.

[0035] IV. Aluminum Metal Impregnation

[0036] Place the aluminum metal block weighed in step one into the graphite mold at the bottom of the infiltration furnace chamber. Place the graphene-nanoscale hard reinforcement-aluminum preform obtained in step three into the upper part of the infiltration furnace chamber. Heat the vacuum infiltration furnace and heat the preform to 560-650℃ at 3-10℃ / min, and hold for 0.5-3h. Heat the aluminum metal block weighed in step one to 780-880℃ and hold for 0.5-2h to obtain molten aluminum metal. Immerse the preheated graphene-nanoscale hard reinforcement-aluminum preform into the molten aluminum metal and stop heating. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained.

[0037] V. Large Plastic Deformation Treatment and Composition Homogenization

[0038] The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

[0039] This embodiment has the following beneficial effects:

[0040] 1. This embodiment introduces a second type of hard nano-reinforcement during the ball milling process of graphene and aluminum powder. This nano-sized grinding ball continuously collides with the graphene sheet during the ball milling process, achieving a much better effect than conventional millimeter-sized grinding balls in terms of breaking, thinning, and dispersing graphene. This results in high-quality dispersion of graphene and improves the strengthening efficiency of graphene.

[0041] 2. The nanoscale hard reinforcement introduced in this embodiment can enhance the friction between the grinding ball and the aluminum powder, increasing the grinding energy. While general powder metallurgy methods aim to disperse the reinforcement on the surface of the aluminum powder, this embodiment, due to its higher grinding energy, allows for a continuous cycle of cold welding and crushing of the aluminum powder. This facilitates the penetration of graphene and the nanoscale hard reinforcement into the interior of the aluminum powder and even into the aluminum grains, increasing the dispersible range of the reinforcement and significantly improving the dispersion effect.

[0042] 3. In this embodiment, by introducing a hard nano-reinforcement into the matrix grains, it plays an additional second-phase strengthening role in the matrix. When dislocations encounter graphene during slip, the layered structure of graphene makes the dislocations easily absorbed. However, when they encounter the hard nano-reinforcement, they can only slip through a bypass mechanism. Therefore, the introduction of the hard nano-reinforcement in this embodiment increases the dislocation density of the matrix and improves the work hardening rate.

[0043] 4. This embodiment introduces nano-hard reinforcements to suppress grain growth during the heat treatment process. Generally, when the solution treatment temperature of a heat-treatable aluminum alloy matrix exceeds 500°C, grains grow rapidly at this temperature. This embodiment introduces additional nano-reinforcements to pin grain boundaries, suppressing grain growth and achieving a stronger grain refinement strengthening effect.

[0044] 5. In the composite material prepared in this embodiment, the defects of graphene are controllable and it does not react with aluminum. Through the control of the ball milling process, excessive defects are not introduced, and the graphene structure remains intact, making it difficult to react with aluminum to form harmful intermetallic compounds, thus achieving a high-quality composite of graphene and aluminum. The excellent interface and stronger matrix further enhance the load transfer effect.

[0045] 6. The nano-reinforcement-assisted graphene-reinforced aluminum matrix composite material prepared in this embodiment achieves the combination of zero-dimensional and two-dimensional, variable and rigid reinforcements. The zero-dimensional rigid reinforcement promotes dislocation multiplication during deformation, while the two-dimensional variable graphene absorbs dislocations and coordinates matrix deformation, thereby achieving a comprehensive improvement in strength and plasticity and obtaining a synergistic effect. Furthermore, the preparation process is simple, the parameters are controllable, the cost is low, and the performance is excellent, representing a breakthrough compared to current graphene / aluminum preparation processes.

[0046] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the graphene described in step one is few-layer graphene with an average sheet diameter of 100nm to 10μm and an average thickness of 0.3 to 20nm.

[0047] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the nanoscale hard reinforcement in step 1 is nano-boron carbide, nano-titanium carbide, nano-alumina, nano-silicon oxide, nano-silicon nitride, or nano-silicon carbide, with an average particle size of 10-1000 nm.

[0048] Specific Implementation Method Four: This implementation method differs from one of Specific Implementation Methods One to Three in that the aluminum metal mentioned in step one is one or a combination of several of the following: Al-Si alloy, Al-Cu alloy, Al-Mg alloy, Al-Si-Cu alloy, Al-Si-Mg alloy, Al-Cu-Mg alloy, Al-Zn-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Be alloy, Al-Li alloy, and Al-Si-Cu-Mg alloy. The Al-Si alloy contains 0.5%–25% Si by mass; the Al-Cu alloy contains 0.5%–53% Cu by mass; the Al-Mg alloy contains 0.5%–38% Mg by mass; the Al-Si-Cu alloy contains 0.5%–25% Si and 0.5%–53% Cu by mass; the Al-Si-Mg alloy contains 0.5%–25% Si and 0.5%–38% Mg by mass; the Al-Cu-Mg alloy contains 0.5%–53% Cu and 0.5%–38% Mg by mass; Al-Z In n-Cu alloys, the mass fraction of Zn is 0.5%–55%, and the mass fraction of Cu is 0.5%–53%; in Al-Zn-Mg-Cu alloys, the mass fraction of Zn is 0.5%–55%, the mass fraction of Mg is 0.5%–38%, and the mass fraction of Cu is 0.5%–53%; in Al-Be alloys, the mass fraction of Be is 0.5%–20%; in Al-Li alloys, the mass fraction of Li is 0.5%–35%; and in Al-Si-Cu-Mg alloys, the mass fraction of Si is 0.5%–25%, the mass fraction of Cu is 0.5%–53%, and the mass fraction of Mg is 0.5%–38%.

[0049] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One through Four in that:

[0050] The long-term uniform dispersion ball milling process described in step two is as follows: the ball milling speed is 50-150 rpm, and the ball milling time is 3-18 h;

[0051] The short-time high-energy ball milling process described in step two is as follows: the ball milling speed is 150-300 rpm, and the ball milling time is 1-6 hours.

[0052] Specific Implementation Method Six: This implementation method differs from one of Specific Implementation Methods One to Five in that the cold pressing process described in step three is as follows: the mixed powder is pressurized to 5 to 15 MPa at a pressurization rate of 0.1 to 10 mm / min and held at that pressure for 10 to 30 minutes.

[0053] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the atmosphere inside the impregnation furnace used in step four is one of vacuum, nitrogen atmosphere, or air atmosphere.

[0054] Specific Implementation Method Eight: This implementation method differs from one of the specific implementation methods one to seven in that the large plastic deformation treatment described in step five is an extrusion, rolling, or forging deformation treatment.

[0055] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Eight in that the temperature of the extrusion deformation treatment or rolling treatment is 400℃~500℃, and the deformation ratio is (7~50):1.

[0056] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the temperature for homogenizing the components in step 5 is 450℃~550℃ and the time is 1~6h.

[0057] Example 1

[0058] The preparation method of the nano-reinforced graphene-reinforced aluminum matrix composite material in this embodiment is carried out according to the following steps:

[0059] I. Selection of Powder Components

[0060] Weigh out 1 wt.% graphene, 10 wt.% nanoscale hard reinforcement, 1 wt.% control agent, and the balance aluminum metal powder as raw materials; weigh out aluminum metal bulk, with a weight ratio of aluminum metal bulk to aluminum metal powder of 5:1; the aluminum metal powder and aluminum metal bulk are made of the same material; the control agent is stearic acid;

[0061] The graphene mentioned in step one is few-layer graphene with an average sheet diameter of 1 μm and an average thickness of 5 nm.

[0062] The nanoscale hard reinforcement in step one is nano-silicon carbide with an average particle size of 150 nm;

[0063] The aluminum metal mentioned in step one is 6061Al metal, and the average particle size of the aluminum metal powder is 10μm;

[0064] II. Dispersion Process

[0065] Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling in sequence. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene and cause it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling can also continuously cold weld and break down the aluminum powder, thereby allowing the nanoscale hard reinforcement to enter the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder.

[0066] The long-term uniform dispersion ball milling process described in step two is as follows: the ball milling speed is 100 rpm and the ball milling time is 6 hours; the short-term high-energy ball milling process described in step two is as follows: the ball milling speed is 250 rpm and the ball milling time is 2 hours.

[0067] III. Preforming of Pre-formed Powder

[0068] The composite pre-powder was loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the mold was placed in a heating furnace, filled with nitrogen, and heated to 600℃ at 5℃ / min and held for 4h to allow the control agent to fully react and volatilize.

[0069] The cold pressing process described in step three is as follows: the mixed powder is pressurized to 10 MPa at a pressurization rate of 2 mm / min and held at the pressure for 10 min;

[0070] IV. Aluminum Metal Impregnation

[0071] The aluminum metal block weighed in step one is placed in the graphite mold at the bottom of the infiltration furnace. The graphene-nanoscale hard reinforcement-aluminum preform obtained in step three is placed in the upper part of the infiltration furnace. The vacuum infiltration furnace is heated, and the preform is heated to 600°C at 5°C / min and held for 3 hours. The aluminum metal block weighed in step one is heated to 800°C and held for 1 hour to obtain molten aluminum metal. The preheated graphene-nanoscale hard reinforcement-aluminum preform is immersed into the molten aluminum metal and then heating is stopped. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained.

[0072] The atmosphere inside the infiltration furnace used in step four is a nitrogen atmosphere;

[0073] V. Large Plastic Deformation Treatment and Composition Homogenization

[0074] The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

[0075] The large plastic deformation treatment described in step five is extrusion at a temperature of 480℃ and a deformation ratio of 10:1;

[0076] The homogenization treatment of the components in step five is carried out at a temperature of 540℃ for 4 hours.

[0077] Figure 1The image shows a micrograph of the pre-formed composite powder obtained in Example 1. It can be seen from the image that the aluminum powder exhibits a slight cold-welded appearance, but is much smaller than the original particle size, indicating that the aluminum powder has achieved a repeated cold-welding-crushing cycle, which is beneficial for the dispersion of the reinforcement in the matrix. The graphene flakes in the field of view have been greatly reduced in size and thickness, which proves the beneficial effect of nano-silicon carbide on dispersion. The nano-silicon carbide itself is also dispersed relatively uniformly. Figure 2 The image shows a Raman image of the nano-reinforced graphene-reinforced aluminum matrix composite material obtained in Example 1. It can be seen from the image that the defects in the graphene are still within a reasonable range, and there are no excessive defects due to the increase in ball milling energy, which will not lead to the formation of Al4C3. Figure 3 The image shows the metallographic microstructure of the nano-reinforced graphene-reinforced aluminum matrix composite obtained in Example 1. It can be seen that the composite material has almost no pores or agglomerations, the reinforcement is uniformly dispersed, and the composite material has high density. In the nano-reinforced graphene-reinforced aluminum matrix composite, the graphene is broken down, thinned, and dispersed, improving the dispersion of both components within the matrix grains and increasing dispersion efficiency, without causing excessive defect-induced Al4C3 formation. It achieves a combination of zero-dimensional and two-dimensional, variable and rigid reinforcements. The zero-dimensional rigid reinforcement promotes dislocation multiplication during deformation, while the two-dimensional variable graphene absorbs dislocations and coordinates matrix deformation, achieving a comprehensive improvement in strength and plasticity. Furthermore, the nano-reinforcement helps graphene suppress grain growth behavior during homogenization treatment (above 500℃), improving the grain refinement strengthening effect. This invention addresses the problem of crack propagation in the matrix due to the mismatch between graphene strength and matrix strength in graphene / Al composite systems. Taking 6061Al as an example, nano-silicon carbide reinforcement more than doubles the matrix strength, improving the strength matching between the reinforcement and the matrix. This prevents premature microcrack formation in the matrix during stress transfer, and inhibits the propagation of microcracks within the matrix. The combination of the two reinforcements achieves a synergistic effect. The nano-reinforced graphene-reinforced aluminum matrix composite prepared in this embodiment has an elastic modulus of 96 GPa, a yield strength of 482 MPa, a tensile strength of 555 MPa, and an elongation of 10.4%.

[0078] Example 2:

[0079] The preparation method of the nano-reinforced graphene-reinforced aluminum matrix composite material in this embodiment is carried out according to the following steps:

[0080] I. Selection of Powder Components

[0081] Weigh out 1 wt.% graphene, 5 wt.% nanoscale hard reinforcement, 1 wt.% control agent, and the balance aluminum metal powder as raw materials; weigh out aluminum metal bulk, with a weight ratio of aluminum metal bulk to aluminum metal powder of 5:1; the aluminum metal powder and aluminum metal bulk are made of the same material; the control agent is stearic acid;

[0082] The graphene mentioned in step one is few-layer graphene with an average sheet diameter of 1 μm and an average thickness of 5 nm.

[0083] The nanoscale hard reinforcement in step one is nano-silicon carbide with an average particle size of 150 nm;

[0084] The aluminum metal mentioned in step one is 6061Al metal, and the average particle size of the aluminum metal powder is 10μm;

[0085] II. Dispersion Process

[0086] Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling in sequence. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene and cause it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling can also continuously cold weld and break down the aluminum powder, thereby allowing the nanoscale hard reinforcement to enter the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder.

[0087] The long-term uniform dispersion ball milling process described in step two is as follows: the ball milling speed is 100 rpm and the ball milling time is 6 hours; the short-term high-energy ball milling process described in step two is as follows: the ball milling speed is 250 rpm and the ball milling time is 2 hours.

[0088] III. Preforming of Pre-formed Powder

[0089] The composite pre-powder was loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the mold was placed in a heating furnace, filled with nitrogen, and heated to 600℃ at 5℃ / min and held for 4h to allow the control agent to fully react and volatilize.

[0090] The cold pressing process described in step three is as follows: the mixed powder is pressurized to 10 MPa at a pressurization rate of 2 mm / min and held at the pressure for 10 min;

[0091] IV. Aluminum Metal Impregnation

[0092] The aluminum metal block weighed in step one is placed in the graphite mold at the bottom of the infiltration furnace. The graphene-nanoscale hard reinforcement-aluminum preform obtained in step three is placed in the upper part of the infiltration furnace. The vacuum infiltration furnace is heated, and the preform is heated to 600°C at 5°C / min and held for 3 hours. The aluminum metal block weighed in step one is heated to 800°C and held for 1 hour to obtain molten aluminum metal. The preheated graphene-nanoscale hard reinforcement-aluminum preform is immersed into the molten aluminum metal and then heating is stopped. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained.

[0093] The atmosphere inside the infiltration furnace used in step four is a nitrogen atmosphere;

[0094] V. Large Plastic Deformation Treatment and Composition Homogenization

[0095] The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

[0096] The large plastic deformation treatment described in step five is extrusion at a temperature of 480℃ and a deformation ratio of 10:1;

[0097] The homogenization treatment of the components in step five is carried out at a temperature of 540℃ for 4 hours.

[0098] The nano-reinforced graphene-reinforced aluminum matrix composite material prepared in Example 2 has an elastic modulus of 87 GPa, a yield strength of 423 MPa, a tensile strength of 492 MPa, and an elongation of 16.7%.

[0099] Example 3:

[0100] The preparation method of the nano-reinforced graphene-reinforced aluminum matrix composite material in this embodiment is carried out according to the following steps:

[0101] I. Selection of Powder Components

[0102] Weigh out 1 wt.% graphene, 2 wt.% nanoscale hard reinforcement, 1 wt.% control agent, and the balance aluminum metal powder as raw materials; weigh out aluminum metal bulk, with a weight ratio of aluminum metal bulk to aluminum metal powder of 5:1; the aluminum metal powder and aluminum metal bulk are made of the same material; the control agent is stearic acid;

[0103] The graphene mentioned in step one is few-layer graphene with an average sheet diameter of 1 μm and an average thickness of 5 nm.

[0104] The nanoscale hard reinforcement in step one is nano-silicon carbide with an average particle size of 150 nm;

[0105] The aluminum metal mentioned in step one is 6061Al metal, and the average particle size of the aluminum metal powder is 10μm;

[0106] II. Dispersion Process

[0107] Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling in sequence. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene and cause it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling can also continuously cold weld and break down the aluminum powder, thereby allowing the nanoscale hard reinforcement to enter the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder.

[0108] The long-term uniform dispersion ball milling process described in step two is as follows: the ball milling speed is 100 rpm and the ball milling time is 6 hours; the short-term high-energy ball milling process described in step two is as follows: the ball milling speed is 250 rpm and the ball milling time is 2 hours.

[0109] III. Preforming of Pre-formed Powder

[0110] The composite pre-powder was loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the mold was placed in a heating furnace, filled with nitrogen, and heated to 600℃ at 5℃ / min and held for 4h to allow the control agent to fully react and volatilize.

[0111] The cold pressing process described in step three is as follows: the mixed powder is pressurized to 10 MPa at a pressurization rate of 2 mm / min and held at the pressure for 10 min;

[0112] IV. Aluminum Metal Impregnation

[0113] The aluminum metal block weighed in step one is placed in the graphite mold at the bottom of the infiltration furnace. The graphene-nanoscale hard reinforcement-aluminum preform obtained in step three is placed in the upper part of the infiltration furnace. The vacuum infiltration furnace is heated, and the preform is heated to 600°C at 5°C / min and held for 3 hours. The aluminum metal block weighed in step one is heated to 800°C and held for 1 hour to obtain molten aluminum metal. The preheated graphene-nanoscale hard reinforcement-aluminum preform is immersed into the molten aluminum metal and then heating is stopped. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained.

[0114] The atmosphere inside the infiltration furnace used in step four is a nitrogen atmosphere;

[0115] V. Large Plastic Deformation Treatment and Composition Homogenization

[0116] The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

[0117] The large plastic deformation treatment described in step five is extrusion at a temperature of 480℃ and a deformation ratio of 10:1;

[0118] The homogenization treatment of the components in step five is carried out at a temperature of 540℃ for 4 hours.

[0119] The nano-reinforced graphene-reinforced aluminum matrix composite material prepared in Example 3 has an elastic modulus of 101 GPa, a yield strength of 511 MPa, a tensile strength of 597 MPa, and an elongation of 6.5%.

Claims

1. A method for preparing a nano-reinforced graphene-reinforced aluminum-based composite material, characterized in that: The preparation method of nano-reinforced graphene-reinforced aluminum matrix composite material is carried out according to the following steps: I. Selection of Powder Components Weigh 0.1~4 wt.% of graphene, 1~10 wt.% of nanoscale hard reinforcement, 0.5~3 wt.% of control agent and the balance of aluminum metal powder as raw materials; weigh aluminum metal block, the weight ratio of aluminum metal block to aluminum metal powder is (3~10):1; the aluminum metal powder and aluminum metal block are made of the same material. The control agent is stearic acid; II. Dispersion Process Weighed graphene, nanoscale hard reinforcement, control agent, and aluminum powder are placed in a ball mill jar and subjected to long-term uniform dispersion ball milling and short-term high-energy ball milling in sequence. In high-energy ball milling, the nanoscale hard reinforcement can impact the graphene and cause it to stratify and break down, achieving a more uniform dispersion effect. High-energy ball milling can also continuously cold weld and break down the aluminum powder, thereby allowing the nanoscale hard reinforcement to enter the interior of the aluminum matrix grains. After ball milling, the powder is sieved to obtain the pre-formed composite material powder. III. Preforming of Pre-formed Powder The composite pre-powder is loaded into a cold pressing mold and cold-pressed to obtain a graphene-nanoscale hard reinforcement-aluminum pre-body; the graphene-nanoscale hard reinforcement-aluminum pre-body is placed in a heating furnace, filled with nitrogen, and heated at 600℃ to allow the control agent to fully react and volatilize. IV. Aluminum Metal Impregnation Place the aluminum metal block weighed in step one into the graphite mold at the bottom of the infiltration furnace chamber. Place the graphene-nanoscale hard reinforcement-aluminum preform obtained in step three into the upper part of the infiltration furnace chamber. Heat the vacuum infiltration furnace and heat the preform to 560-650℃ at 3-10℃ / min, and hold for 0.5-3h. Heat the aluminum metal block weighed in step one to 780-880℃ and hold for 0.5-2h to obtain molten aluminum metal. Immerse the preheated graphene-nanoscale hard reinforcement-aluminum preform into the molten aluminum metal and stop heating. After natural cooling, a high-density nano-reinforcement-assisted graphene-reinforced aluminum matrix composite ingot is obtained. V. Large Plastic Deformation Treatment and Composition Homogenization The highly dense nano-reinforced graphene-reinforced aluminum matrix composite ingot obtained in step four is subjected to large plastic deformation treatment and composition homogenization treatment in sequence to obtain nanoscale hard reinforced graphene-reinforced aluminum matrix composite material, thus completing the process.

2. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The graphene mentioned in step one is few-layer graphene with an average sheet diameter of 100nm~10μm and an average thickness of 0.3~20nm.

3. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The nanoscale hard reinforcement mentioned in step one is nano-boron carbide, nano-titanium carbide, nano-alumina, nano-silicon oxide, nano-silicon nitride, or nano-silicon carbide, with an average particle size of 10~1000 nm.

4. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The aluminum metal mentioned in step one is one or a combination of several of the following: Al-Si alloy, Al-Cu alloy, Al-Mg alloy, Al-Si-Cu alloy, Al-Si-Mg alloy, Al-Cu-Mg alloy, Al-Zn-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Be alloy, Al-Li alloy, and Al-Si-Cu-Mg alloy. The mass fraction of Si in the Al-Si alloy is 0.5%~25%; The mass fraction of Cu in the Al-Cu alloy is 0.5% to 53%. The mass fraction of Mg in the Al-Mg alloy is 0.5%~38%; In Al-Si-Cu alloys, the mass fraction of Si is 0.5%~25%, and the mass fraction of Cu is 0.5%~53%. In Al-Si-Mg alloys, the mass fraction of Si is 0.5%~25%, and the mass fraction of Mg is 0.5%~38%. In Al-Cu-Mg alloys, the mass fraction of Cu is 0.5%~53%, and the mass fraction of Mg is 0.5%~38%. In Al-Zn-Cu alloys, the mass fraction of Zn is 0.5%~55%, and the mass fraction of Cu is 0.5%~53%. In Al-Zn-Mg-Cu alloys, the mass fraction of Zn is 0.5%~55%, the mass fraction of Mg is 0.5%~38%, and the mass fraction of Cu is 0.5%~53%. The mass fraction of Be in Al-Be alloys is 0.5% to 20%; The mass fraction of Li in Al-Li alloys ranges from 0.5% to 35%. The Al-Si-Cu-Mg alloy has a Si mass fraction of 0.5% to 25%, a Cu mass fraction of 0.5% to 53%, and a Mg mass fraction of 0.5% to 38%.

5. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The long-term uniform dispersion ball milling process described in step two is as follows: the ball milling speed is 50~150 rpm, and the ball milling time is 3~18h; The short-time high-energy ball milling process described in step two is as follows: the ball milling speed is 150~300 rpm, and the ball milling time is 1~6 hours.

6. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The cold pressing process described in step three is as follows: the mixed powder is pressurized to 5-15 MPa at a pressurization rate of 0.1-10 mm / min and held at the pressure for 10-30 min.

7. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The atmosphere inside the impregnation furnace used in step four is one of vacuum, nitrogen, or air.

8. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The large plastic deformation treatment described in step five is an extrusion, rolling, or forging deformation treatment.

9. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 8, characterized in that: The temperature of the extrusion deformation treatment or rolling treatment is 400℃~500℃, and the deformation ratio is (7~50):

1.

10. The method for preparing the nano-reinforced graphene-reinforced aluminum matrix composite material according to claim 1, characterized in that: The homogenization treatment of the components in step five is carried out at a temperature of 450℃~550℃ for 1~6 hours.

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