High thermal conductive lightweight layered graphene reinforced aluminum matrix composite and method of making same

Abstract

The application discloses a kind of high-thermal-conductivity light-weight layered graphene reinforced aluminum matrix composite material and preparation method thereof.The application includes the following steps: (1) shot blasting treatment is carried out on aluminum plate, and the aluminum plate after shot blasting is rolled, and the aluminum plate after rolling is surface treated;(2) graphene powder is soaked with alcohol, and is uniformly mixed with ultrasonic wave;(3) the graphene powder after alcohol soaking is coated on the surface of the aluminum plate after surface treatment, and the aluminum plate after surface treatment is stacked on the graphene powder layer, forming a stacked plate, after four corners are fixed, the stacked plate is vacuum hot-pressed;(4) the stacked plate after vacuum hot-pressing is high-temperature rolled with not less than 50% reduction per pass, and air-cooled after rolling;(5) the plate after rolling is annealed, and the plate after annealing is wire cut, to obtain two pieces of the same size;(6) repeat steps (3)-(5).The application realizes the effective combination of graphene and aluminum matrix, and the prepared composite material has good performance.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, specifically relating to a high thermal conductivity, lightweight layered graphene-reinforced aluminum matrix composite material and its preparation method. Background Technology

[0002] With the development of industries such as aerospace, electronic devices, and new energy vehicles, high thermal conductivity metal materials are being used more and more widely. High thermal conductivity aluminum alloys have attracted much attention due to their lightweight, high strength, good thermal conductivity, strong corrosion resistance, and good processing performance. However, with the rapid development of modern industry, the requirements for material performance in various fields are gradually increasing. Aluminum alloys, which generally have high thermal conductivity, have relatively low strength. This means that in some applications requiring high strength, the thermal conductivity of aluminum alloys often cannot meet the requirements, making it urgent to develop high-strength, high thermal conductivity aluminum alloys and composite materials.

[0003] Graphene is carbon atoms arranged in sp... 2 Two-dimensional nanomaterials with hybrid composition possess ultra-high electrical conductivity (2000 Sm). -1 It has a high Young's modulus (1 TPa), a high fracture strength (130 GPa), and a thermal conductivity as high as 5300 W / m. -1 K -1 It is far superior to diamond (2000Wm), which is also a carbon material. -1 K -1 ) and carbon nanotubes (single-walled 3500Wm) -1 K -1 Graphene is an ideal reinforcing material for high-strength and high-thermal-conductivity aluminum-based composite materials. In recent years, graphene aluminum-based composite materials have also become a major development direction for heat-resistant aluminum alloys.

[0004] With the deepening research on graphene-aluminum matrix composites, the preparation processes and methods are becoming increasingly diverse. The preparation process mainly consists of two parts: uniform dispersion of graphene in the aluminum matrix and composite material molding. The main method for preparing mixed powders is ball milling, including planetary ball milling, high-energy ball milling, segmented ball milling, dry milling, and wet milling. The main method for preparing composite materials is powder metallurgy, including hot pressing sintering, hot isostatic pressing, and hot extrusion. In 2021, Tielong Han published an article titled "Simultaneously enhanced strength and ductility of Al matrix composites through the introduction of intragranular nano-sized graphene nanoplates" in *Composites Part B*. In this article, Han et al. used segmented ball milling (SMBM) to uniformly disperse high-content graphene nanosheets in the aluminum matrix, thereby simultaneously improving both strength and toughness. In his 2016 article "Preparation and tensile properties of homogeneously dispersed graphene reinforced aluminum matrix composites" published in *Materials and Design*, Xin Gao prepared negatively charged graphene oxide sheets using a modified Hummers method. He then coated aluminum powder with hexadecyltrimethylammonium bromide (CTAB) to give the aluminum powder a positive charge, and subsequently achieved uniform adsorption of graphene oxide nanosheets onto pure aluminum powder via electrostatic self-assembly. Chaoyu Wang et al. used chemical vapor deposition to grow vertically aligned graphene nanosheets (GNPs) on the surface of graphite flakes (Gr(GNP)), and then prepared Gr(GNP) / Al composites via vacuum hot pressing sintering.

[0005] In summary, existing technologies for preparing graphene-reinforced aluminum matrix composites still face several challenges. Firstly, graphene and aluminum differ significantly in melting point, hardness, and other properties. Graphene's poor wettability leads to buoyancy issues when mixed with the aluminum matrix, making it difficult for graphene powder to achieve effective and uniform dispersion within the aluminum matrix. This results in weak interfacial bonding and low load transfer strengthening effects. Secondly, traditional ball milling or dry milling methods struggle to achieve strong bonding interfaces without damaging the graphene. Some processes can achieve strong bonding interfaces, but their preparation efficiency is low. Furthermore, the actual measured mechanical properties of graphene-reinforced metal matrix composites are generally lower than theoretical predictions. Therefore, the preparation of high-performance graphene-reinforced aluminum matrix composites remains a significant challenge. Summary of the Invention

[0006] The purpose of this invention is to provide a high thermal conductivity, lightweight layered graphene-reinforced aluminum matrix composite material and its preparation method.

[0007] The technical solution for achieving the objective of this invention is: a method for preparing a high thermal conductivity, lightweight layered graphene-reinforced aluminum-based composite material, comprising the following steps:

[0008] Step (1): Shot peening the aluminum plate, rolling the shot peened aluminum plate, and surface treatment of the rolled aluminum plate.

[0009] Step (2): Moisten the graphene powder with alcohol and mix it evenly with ultrasound;

[0010] Step (3): The graphene powder soaked in alcohol in step (2) is coated onto the surface of the surface-treated aluminum plate. The surface-treated aluminum plate is stacked on the coated graphene powder layer to form a stacked plate. After the four corners are fixed, the stacked plate is vacuum hot-pressed.

[0011] Step (4): Perform high-temperature rolling on the stacked plates after vacuum hot pressing, with a reduction of not less than 50% per pass, and air cool after rolling;

[0012] Step (5): Anneal the rolled sheet, and wire cut the annealed sheet to obtain two pieces of the same size;

[0013] Step (6): Repeat steps (3)-(5) to obtain a high thermal conductivity lightweight layered graphene-reinforced aluminum matrix composite material.

[0014] Furthermore, the aluminum plate used in step (1) has the following dimensions: length 10-30cm, width 10-30cm, and thickness 3-15mm.

[0015] Furthermore, the shot peening process in step (1) specifically involves using 3-5mm steel shot, rotating at a speed of 25-50m / s, and processing for 15-30min.

[0016] Furthermore, the rolling reduction in step (1) is 12% to 20%.

[0017] Furthermore, the surface treatment in step (1) specifically involves grinding the surface of the rolled aluminum plate, brushing it with a steel brush to remove the oxide layer, and then soaking it in acetone and ultrasonically treating it.

[0018] Furthermore, in step (3), the vacuum hot pressing is specifically as follows: the vacuum degree is less than 0.3 Pa, the pressure is 50-100 MPa, the heat preservation temperature is 450-550℃, and the heat preservation time is 1-2 h.

[0019] Furthermore, the high-temperature rolling in step (4) specifically involves: preheating at a temperature of 450-550℃ and a holding time of 20-30 minutes before rolling, with a reduction of 50-70%.

[0020] Furthermore, the annealing process in step (5) is as follows: the annealing temperature is 150-250℃, the holding time is 30-60min, and the cooling method is air cooling.

[0021] Further, repeat steps (3)-(5) 1-10 times.

[0022] A high thermal conductivity, lightweight layered graphene-reinforced aluminum-based composite material is prepared using the method described above.

[0023] Compared with the prior art, the significant advantages of this invention are:

[0024] This invention utilizes shot peening to improve the surface roughness of aluminum plates and create a gradient microstructure of nanocrystalline, ultrafine, and coarse-grained layers along the thickness direction. Alcohol-soaked graphene powder is then coated onto the aluminum plate surface. After stacking the plates, subsequent large-scale deformation ensures the graphene powder is well-formed in its designated locations, achieving effective bonding between the graphene and the aluminum matrix. The smaller nanocrystalline and ultrafine grains on the gradient microstructure created by shot peening promote better uniform dispersion and high wettability of the graphene within the aluminum matrix during subsequent cumulative rolling, forming a residual stress layer on the surface and enhancing the strength of the aluminum matrix. Subsequent rolling further promotes the formation of elongated grains within the matrix, increasing both elongation and electron throughput, thus pre-enhancing the thermal conductivity of the aluminum matrix.

[0025] This invention can effectively and tightly bond graphene powder with an aluminum matrix, leveraging the high thermal conductivity of graphene to further improve the thermal conductivity of graphene-aluminum composite materials. Compared with other preparation methods (such as powder metallurgy), the cumulative rolling method does not damage the microstructure of graphene, and gives it a higher bonding strength with the matrix metal. It does not generate impurity compounds, and is more efficient, simpler in process, shorter in production cycle, and easier to achieve large-volume mass production.

[0026] The preparation method of this invention is universal and has guiding significance for improving the thermal conductivity and mechanical properties of other types of alloys; it also has important practical significance for achieving lightweighting and cost reduction. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation method of the present invention.

[0028] Figure 2 This is a schematic diagram of the microstructure of the aluminum plate after shot peening according to the present invention.

[0029] Figure 3 This is a schematic diagram of aluminum plates and graphene stacked together. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] A method for preparing a high thermal conductivity lightweight layered graphene-reinforced aluminum matrix composite material is disclosed. This method can improve the thermal conductivity of aluminum alloys while maintaining the excellent properties of the raw materials.

[0032] The technical solution for realizing the present invention is:

[0033] Step (1): Prepare industrial pure aluminum plate material and graphene powder;

[0034] Step (2): First, the surface of the cleaned pure aluminum plate is subjected to high-energy shot peening and nano-treatment. Then, the plate after nano-treatment is rolled. Then, the surface of the rolled plate is polished and scrubbed with a steel brush to remove the oxide layer. Then, it is soaked in acetone and ultrasonically treated. The graphene powder is moistened with alcohol and mixed evenly with an ultrasonic machine.

[0035] Step (3): Stack the two materials processed in step (2) together in the order of Al / C / Al (Al represents industrial pure aluminum, C represents graphene powder), fix the four corners, and then perform vacuum hot pressing on the stacked plate to fix its surface.

[0036] Step (4): Roll the stacked plates after vacuum hot pressing, and then air cool them;

[0037] Step (5): Anneal the rolled sheet, wire cut the annealed sheet to obtain two pieces of the same size, and repeat the above steps (4-6).

[0038] Furthermore, the dimensions of the board in step (1) are: length and width of 10-30cm, and thickness of 3-15mm.

[0039] Furthermore, the high-energy shot peening surface nano-treatment described in step (2) uses 3-5mm steel shot, rotates at 25m / s, and takes 15-30min.

[0040] Furthermore, the rolling reduction in step (2) is 12% to 50%;

[0041] Furthermore, the vacuum hot pressing treatment in step (3) is specifically as follows: the vacuum degree is less than 0.3 Pa, the pressure is 50-100 MPa, the heat preservation temperature is 450-550℃, and the heat preservation time is 1-2 h;

[0042] Furthermore, the rolling process in step (4) is as follows: the preheating temperature is 450-550℃, the holding time is 20-30min, and the pressing amount is 50-70%.

[0043] Furthermore, the annealing process in step (5) is as follows: the annealing temperature is 150-250℃, the holding time is 30-60min, and the cooling method is air cooling;

[0044] Furthermore, repeat the above steps (3-5) 1-10 times.

[0045] Example 1

[0046] Step (1): Prepare an industrial pure aluminum plate material with a length of 15cm, a width of 10cm, and a thickness of 10mm, and 5g of single-layer graphene powder;

[0047] Step (2): Select 5mm GCr15 steel shot. The high-energy shot peening equipment rotates at 25m / s and the processing time is 15min. High-energy shot peening is performed on the pure aluminum plate. Then, the plate after nano-treatment is rolled, maintaining a small amount of deformation per pass, with a total deformation of 12%, 4 passes, and a rolling speed of 5m / s. The sample thickness is successively from 10mm to 9.5mm, to 9.0mm, to 8.8mm. Then, the surface of the rolled plate is polished, brushed with a steel brush to remove the oxide layer, and then soaked in acetone for 20min and ultrasonically treated. The graphene powder is moistened with alcohol and mixed evenly with an ultrasonic machine. Then, the moistened graphene is evenly brushed onto the surface of the treated composite material with a brush and allowed to dry naturally in the air.

[0048] Step (3): Stack the two materials processed in step (2) together in Al / C / Al order, fix the four corners, and then perform vacuum hot pressing on the fixed stacked plates under the conditions of vacuum degree of 0.2Pa, pressure of 50MPa, temperature of 550℃, and heat preservation time of 2h.

[0049] Step (4): Roll the stacked plates after vacuum hot pressing. The preheating temperature is 450℃, the holding time is 20min, the pressing amount is 50%, and the plates are air-cooled after rolling.

[0050] Step (5): Anneal the rolled sheet at 250℃ for 30 minutes. Wire cut the annealed sheet to obtain two pieces of the same size and repeat steps (3-5) above. Repeat the above steps twice to obtain a 6-layer composite sheet.

[0051] Example 2

[0052] Step (1): Prepare an industrial pure aluminum plate material with a length of 10cm, a width of 5cm, and a thickness of 8mm, and 4g of single-layer graphene powder;

[0053] Step (2): Select 3mm GCr15 steel shot. The high-energy shot peening equipment rotates at 40m / s and the treatment time is 30min. High-energy shot peening is performed on the pure aluminum plate. Then, the plate after nano-treatment is rolled, maintaining a small amount of deformation per pass, with a total deformation of 30%, 4 passes, and a rolling speed of 7m / s. The sample thickness is successively from 8mm to 7.2mm, to 6.4mm, to 5.6mm. Then, the surface of the rolled plate is polished and brushed with a steel brush to remove the oxide layer. Then, it is soaked in acetone for 20min and ultrasonically treated. The graphene powder is moistened with alcohol and mixed evenly with an ultrasonic machine. Then, the moistened graphene is evenly brushed onto the surface of the treated composite material with a brush and allowed to dry naturally in the air.

[0054] Step (3): Stack the two materials processed in step (2) together in the order of Al / C / Al, fix the four corners, and then perform vacuum hot pressing on the fixed stacked plates under the conditions of vacuum degree of 0.2Pa, pressure of 50MPa, temperature of 550℃, and heat preservation time of 2h.

[0055] Step (4): Roll the stacked plates after vacuum hot pressing. The preheating temperature is 450℃, the holding time is 20min, the pressing amount is 60%, and the plates are air-cooled after rolling.

[0056] Step (5): Anneal the rolled sheet at 250℃ for 30 minutes. Wire cut the annealed sheet to obtain two identical pieces and repeat steps (3-5) above. Repeat the above steps 5 times to obtain a 15-layer composite sheet.

[0057] Example 3

[0058] Step (1): Prepare an industrial pure aluminum plate material with a length of 5cm, a width of 5cm, and a thickness of 3mm, and 3g of double-layer graphene powder;

[0059] Step (2): Select 3mm GCr15 steel shot. High-energy shot peening equipment with a rotation speed of 50m / s and a processing time of 30min was used to perform high-energy shot peening on pure aluminum plates. Then, the nano-treated plates were rolled, maintaining a small amount of deformation per pass, with a total deformation of 40%, 3 passes, and a rolling speed of 5m / s. The sample thickness was successively reduced from 3mm to 2.4mm to 1.8mm. Then, the surface of the rolled plate was polished and brushed with a steel brush to remove the oxide layer. Subsequently, it was soaked in acetone for 20min and ultrasonically treated. Graphene powder was moistened with alcohol and mixed evenly with an ultrasonic machine. Then, the moistened graphene was evenly brushed onto the surface of the treated composite material with a brush and allowed to dry naturally in the air.

[0060] Step (3): Stack the two materials processed in step (2) together in Al / C / Al order, fix the four corners, and then perform vacuum hot pressing on the fixed stacked plates under the conditions of vacuum degree of 0.2Pa, pressure of 50MPa, temperature of 550℃, and heat preservation time of 2h.

[0061] Step (4): Roll the stacked plates after vacuum hot pressing. The preheating temperature is 450℃, the holding time is 20min, the pressing amount is 70%, and the plates are air-cooled after rolling.

[0062] Step (5): Anneal the rolled sheet at 250℃ for 30 minutes. Wire cut the annealed sheet to obtain two identical pieces and repeat steps (3-5) above. Repeat the above steps 8 times to obtain a 24-layer composite sheet.

[0063] Example 4

[0064] Step (1): Prepare an industrial pure aluminum plate material with a length of 15cm, a width of 10cm, and a thickness of 10mm, and 5g of single-layer graphene powder;

[0065] Step (2): Select 5mm GCr15 steel shot. The high-energy shot peening equipment rotates at 35m / s and the processing time is 15min. High-energy shot peening is performed on the pure aluminum plate. Then, the plate after nano-treatment is rolled, maintaining a small amount of deformation per pass, with a total deformation of 50%, 4 passes, and a rolling speed of 5m / s. The sample thickness is successively from 10mm to 8mm, to 6.5mm, to 5mm. Then, the surface of the rolled plate is polished and brushed with a steel brush to remove the oxide layer. Then, it is soaked in acetone for 20min and ultrasonically treated. The graphene powder is moistened with alcohol and mixed evenly with an ultrasonic machine. Then, the moistened graphene is evenly brushed onto the surface of the treated composite material with a brush and allowed to dry naturally in the air.

[0066] Step (3): Stack the two materials processed in step (2) together in Al / C / Al order, fix the four corners, and then perform vacuum hot pressing on the fixed stacked plates under the conditions of vacuum degree of 0.2Pa, pressure of 50MPa, temperature of 550℃, and heat preservation time of 2h.

[0067] Step (4): Roll the stacked plates after vacuum hot pressing. The preheating temperature is 450℃, the holding time is 20min, the pressing amount is 70%, and the plates are air-cooled after rolling.

[0068] Step (5): Anneal the rolled sheet at 250℃ for 30 minutes. Wire cut the annealed sheet to obtain two identical pieces and repeat steps (3-5) above. Repeat the above steps 10 times to obtain a 30-layer composite sheet.

Claims

1. A method for preparing a high thermal conductivity, lightweight layered graphene-reinforced aluminum-based composite material, characterized in that, Includes the following steps: Step (1): Shot peening is performed on the aluminum plate, the shot-peened aluminum plate is rolled, and the rolled aluminum plate is surface treated; the shot peening process is as follows: 3-5mm steel shot is used, the rotation speed is 25-50m / s, and the treatment time is 15-30min; the rolling reduction in step (1) is 12%-20%; Step (2): Moisten the graphene powder with alcohol and mix it evenly with ultrasound; Step (3): The graphene powder soaked in alcohol in step (2) is coated onto the surface of the surface-treated aluminum plate. The surface-treated aluminum plate is stacked on the coated graphene powder layer to form a stacked plate. After the four corners are fixed, the stacked plate is vacuum hot-pressed. Step (4): Perform high-temperature rolling on the stacked plates after vacuum hot pressing, with a reduction of not less than 50% per pass, and air cool after rolling; Step (5): Anneal the rolled sheet, and wire cut the annealed sheet to obtain two pieces of the same size; Step (6): Repeat steps (3)-(5) to obtain a high thermal conductivity lightweight layered graphene-reinforced aluminum matrix composite material.

2. The method according to claim 1, characterized in that, The dimensions of the aluminum plate used in step (1) are: length 10-30cm, width 10-30cm, and thickness 3-15mm.

3. The method according to claim 2, characterized in that, The surface treatment in step (1) is as follows: the surface of the rolled aluminum plate is polished, scrubbed with a steel brush to remove the oxide layer, and then soaked in acetone and ultrasonically treated.

4. The method according to claim 3, characterized in that, In step (3), the vacuum hot pressing is specifically as follows: the vacuum degree is less than 0.3 Pa, the pressure is 50-100 MPa, the heat preservation temperature is 450-550℃, and the heat preservation time is 1-2 h.

5. The method according to claim 4, characterized in that, In step (4), the high-temperature rolling process specifically involves preheating at a temperature of 450-550℃ and a holding time of 20-30 minutes before rolling, with a reduction of 50-70%.

6. The method according to claim 5, characterized in that, The annealing process in step (5) is as follows: the annealing temperature is 150-250℃, the holding time is 30-60min, and the cooling method is air cooling.

7. The method according to claim 6, characterized in that, Repeat steps (3)-(5) 1-10 times.

8. A high thermal conductivity, lightweight layered graphene-reinforced aluminum-based composite material, characterized in that, Prepared using the method described in any one of claims 1-7.

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