A method for preparing a copper-aluminum composite surface gradient nanostructure material

Abstract

The application relates to a preparation method of a copper-aluminum composite surface gradient nano-structure material plate. The application aims to solve the problems that the strength of the existing aluminum and its alloy as a structure material needs to be further improved, in addition, the heat conduction and electric conduction performance of the aluminum and its alloy is relatively weak compared with copper and its alloy, the cost of copper is relatively high, the density of copper is relatively large, the specific strength of copper is relatively low, and the copper is not suitable for lightweight design of components. The application combines the advantages of Cu and Al, reasonably utilizes the skin effect of metal materials, combines surface alloying and surface nano-technology, introduces graphene to realize self-lubrication, better realizes the gradient distribution and gradient refinement effect of copper in aluminum, forms a composite gradient on the surface of the aluminum alloy, improves the structure and functional characteristics of the aluminum alloy plate, replaces copper and its alloy, effectively reduces the consumption of copper, saves the cost, and reduces the weight of the components.

Description

Technical Field

[0001] This invention relates to a method for preparing a metal composite gradient nanostructure material plate. Background Technology

[0002] Aluminum and its alloys are widely used in automotive, mechanical engineering, electronic communications, and aerospace industries. However, with societal development, traditional aluminum alloys can no longer meet the demands of new technologies and equipment for high strength-ductility matching and integrated structural-functional design. Researching and developing new aluminum alloys to achieve a good strength-ductility match is crucial for expanding the application areas of aluminum materials and promoting their industrial development. To achieve this, one approach is to improve mechanical properties through compositional design, combining forming and heat treatment processes to control the microstructure. However, this method often fails to improve the strength-ductility inverse relationship of metallic materials. Another approach is to structurally design existing commercial aluminum alloys, improving the strength-ductility match through rational structural design, such as layered structures, gradient nanostructures, and core-shell structures. Gradient nanostructures, in particular, can achieve a gradient change in grain size from the nanoscale to tens to hundreds of micrometers within the same material, thereby allowing for greater control over the material's mechanical properties. Gradient nanostructures can be obtained through surface nanostructuring via drastic surface deformation. After surface nanostructuring, a gradient nanostructure layer can be formed on the material surface, thereby improving the overall performance of the material and increasing the service life of the workpiece. Compared to other structural designs, gradient nanostructure preparation methods are more direct, and the surface properties and performance of the prepared materials can be used to quickly determine the process optimization.

[0003] Currently, surface nanostructuring of aluminum alloys has been carried out in various aluminum alloy systems, such as 5, 6, and 7 series aluminum alloys. However, current surface nanostructuring technology is only aimed at the design of microstructures of bulk materials with uniform composition, i.e., achieving a single gradient. Copper and its alloys are widely used as structural components for heat and electricity conduction due to their excellent thermal conductivity, electrical conductivity, and mechanical properties; however, copper is relatively expensive and has a high density, making it unsuitable for lightweight component design. By combining copper with aluminum to form a gradient nanostructure, the physical advantages of copper can be fully utilized while reducing costs. Summary of the Invention

[0004] The purpose of this invention is to address the problem that the strength of aluminum and its alloys as structural materials needs to be further improved, and that their thermal and electrical conductivity is relatively weaker than that of copper and its alloys. However, copper has a high cost, high density, and low specific strength, making it unsuitable for lightweight component design. By combining copper and aluminum and forming a gradient nano-alloyed structure on the aluminum surface, the performance of aluminum can be effectively improved. Based on this, this invention provides a method for preparing copper-aluminum composite surface gradient nanostructure materials.

[0005] A method for preparing a copper-aluminum composite surface gradient nanostructure material is specifically carried out according to the following steps:

[0006] I. Surface Pretreatment:

[0007] First, the Al board is subjected to alkaline washing treatment, and then sandblasting treatment to obtain the Al board with surface pretreatment.

[0008] II. Arc spraying of Cu:

[0009] One or both sides of the pre-treated Al plate are subjected to arc spraying of Cu to obtain a Cu / Al substrate with Cu coating on one or both sides.

[0010] III. Electrophoretic deposition of GO:

[0011] Electrophoretic deposition of GO is performed on a Cu / Al substrate with a Cu coating on one or both sides, followed by drying, to obtain a GO / Cu / Al preform with a GO deposition thin layer.

[0012] IV. Surface mechanical treatment:

[0013] A layer of graphene lubricating oil was coated on the surface of a GO / Cu / Al prefabricated plate with a GO deposition thin layer. The surface of the GO / Cu / Al prefabricated plate with a GO deposition thin layer was subjected to multiple pressure friction treatments under the conditions of applying a load of 300-700 N in the direction perpendicular to the plate plane, a feed rate of 0.1-3 mm / s in the direction parallel to the plate plane, and a pressure friction head rotation speed of 0-900 rpm. The graphene and graphene lubricating oil on the surface of the prefabricated plate achieved self-lubrication during friction and were removed during the friction process, resulting in a copper-aluminum composite surface gradient nanostructure material.

[0014] The principle of this invention:

[0015] The introduction of Cu is to provide a source of alloying solute. By spraying Cu onto the Al surface to form a Cu layer, combined with subsequent surface mechanical treatment, a concentration gradient of Cu can be formed within a certain depth range of Al. Electrophoretic deposition of GO is to form a thin GO film on the Cu coating, which forms a self-lubricating effect with the graphene nanosheets in the cooling lubricating oil and is then placed to peel off during the surface mechanical treatment. Finally, pressure friction is to apply large plastic deformation to the surface. The closer to the surface, the greater the strain and strain rate, and the further away from the surface, the smaller the strain gradually becomes, thereby inducing the formation of gradient nanostructures on the material surface.

[0016] The present invention has the following advantages:

[0017] I. This invention combines the advantages of Cu and Al, makes reasonable use of the skin effect of metallic materials, combines surface alloying and surface nano-sizing, and introduces graphene to achieve self-lubrication to better realize the gradient distribution and gradient refinement effect of copper in aluminum, forming a composite gradient on the surface of aluminum alloy, which can improve the structure and functional characteristics of aluminum alloy sheet, and replace copper and its alloys, effectively reducing copper consumption, saving costs and reducing the weight of components.

[0018] II. This invention can efficiently prepare gradient nano-alloyed materials. The production process is simple and easy to implement, the preparation process is pollution-free, and the cost is low.

[0019] Third, the copper-aluminum composite surface gradient nanostructure material prepared by this invention is dense and has good mechanical properties, thermal conductivity, and electrical conductivity, and has the characteristics of integrated structure and function.

[0020] IV. This invention regulates the material microstructure by adjusting process parameters such as arc spraying and surface mechanical treatment, and regulates the composite gradient according to the different requirements of thermal conductivity and electrical conductivity for different components, so as to obtain specific properties.

[0021] V. The surface hardness gradient range of copper-aluminum composite surface gradient nanostructure materials can reach 70–130 HV, which is 2–4 times higher than that of aluminum matrix; the thermal conductivity range can reach 275–315 W / (m·K), which is 17%–34% higher than that of aluminum matrix; and the electrical conductivity range can reach 4.0–4.5 × 10⁻⁶. 7 The S / m ratio is increased by 14% to 29% compared to the aluminum matrix. Attached Figure Description

[0022] Figure 1 The images show the chemical composition distribution and microstructure of the copper-aluminum composite surface gradient nanostructure material prepared in Example 1. In the image, (a) shows the Al and Cu element distribution on the surface by EDS scanning, (b) shows the Al and Cu element distribution on the cross section by EDS scanning, (c) shows the TEM image of the surface structure, and (d) shows the gradient TEM image of the cross section structure.

[0023] Figure 2 The image shows the hardness gradient of the copper-aluminum composite surface gradient nanostructure material prepared in Example 1. Detailed Implementation

[0024] Specific Implementation Method 1: This implementation method describes a method for preparing a copper-aluminum composite surface gradient nanostructure material, which is specifically completed according to the following steps:

[0025] I. Surface Pretreatment:

[0026] First, the Al board is subjected to alkaline washing treatment, and then sandblasting treatment to obtain the Al board with surface pretreatment.

[0027] II. Arc spraying of Cu:

[0028] One or both sides of the pre-treated Al plate are subjected to arc spraying of Cu to obtain a Cu / Al substrate with Cu coating on one or both sides.

[0029] III. Electrophoretic deposition of GO:

[0030] Electrophoretic deposition of GO is performed on a Cu / Al substrate with a Cu coating on one or both sides, followed by drying, to obtain a GO / Cu / Al preform with a GO deposition thin layer.

[0031] IV. Surface mechanical treatment:

[0032] A layer of graphene lubricating oil was coated on the surface of a GO / Cu / Al prefabricated plate with a GO deposition thin layer. The surface of the GO / Cu / Al prefabricated plate with a GO deposition thin layer was subjected to multiple pressure friction treatments under the conditions of applying a load of 300-700 N in the direction perpendicular to the plate plane, a feed rate of 0.1-3 mm / s in the direction parallel to the plate plane, and a pressure friction head rotation speed of 0-900 rpm. The graphene and graphene lubricating oil on the surface of the prefabricated plate achieved self-lubrication during friction and were removed during the friction process, resulting in a copper-aluminum composite surface gradient nanostructure material.

[0033] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the thickness of the Al plate mentioned in step one is 1mm to 10mm. The other steps are the same as in Specific Implementation Method One.

[0034] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the alkaline washing process described in step one is as follows: the Al plate is immersed in a 5% NaOH solution for 5-10 seconds, then rinsed with water until neutral, and finally dried to obtain the alkaline-washed Al plate. Other steps are the same as in Specific Implementation Method One or Two.

[0035] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the sandblasting process described in step one is as follows: using Al2O3 particles as the abrasive, under conditions of compressed air pressure of 0.2MPa to 0.6MPa, a spray distance of 100mm to 300mm, and a spray angle of 45°, the Al plate after alkaline washing is sandblasted for 10s to 60s. After sandblasting, residual particles on the surface are removed to obtain the Al plate with pre-treated surface. Other steps are the same as in Specific Implementation Methods One to Three.

[0036] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the arc spraying Cu treatment process described in step two is as follows: using Cu wire as the arc spraying material, the pre-treated Al plate is subjected to arc spraying for 2s to 15s under the conditions of a spraying distance of 100mm to 200mm, a spraying voltage of 20V to 40V, and a wire feeding speed of 30mm / s to 80mm / s, to obtain a Cu / Al substrate with a Cu coating on one or both sides. Other steps are the same as in Specific Implementation Methods One to Four.

[0037] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the electrophoretic deposition of GO in step two is as follows: A Cu / Al substrate with a Cu coating on one or both sides is immersed in a deposition solution, and deposition is performed for 10 to 30 seconds under conditions of a voltage of 100V to 150V and the Cu coating facing the electrode plate. The substrate is then removed, dried, and a GO / Cu / Al prefabricated board with a GO deposition thin layer is obtained. The other steps are the same as in Specific Implementation Methods One to Five.

[0038] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the deposition solution is a mixture of graphene, Al(NO3)3, and anhydrous ethanol, wherein the mass-to-volume ratio of graphene, Al(NO3)3, and anhydrous ethanol is (0.2g~0.5g):(0.05g~0.2g):400mL. The other steps are the same as in Specific Implementation Methods One to Six.

[0039] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the number of pressure friction treatments in step four is 1 to 100 times. The other steps are the same as in Specific Implementation Methods One to Seven.

[0040] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the graphene lubricating oil mentioned in step four is a cooling lubricating oil with added graphene nanosheets, and the amount of graphene nanosheets added is 0.1g / L to 0.3g / L. The other steps are the same as in Specific Implementation Methods One to Eight.

[0041] The technical effects of the present invention are verified using the following embodiments:

[0042] Example 1: A method for preparing a copper-aluminum composite surface gradient nanostructure material, specifically completed according to the following steps:

[0043] I. Surface Pretreatment:

[0044] An Al plate was immersed in a 5% NaOH solution for 5 seconds, then rinsed with water until neutral and dried to obtain an Al plate after alkaline washing. Al2O3 particles were used as a spray material, and the Al plate after alkaline washing was sandblasted for 10 seconds under the conditions of compressed air pressure of 0.5 MPa, spray distance of 150 mm and spray angle of 45°. After sandblasting, residual particles on the surface were removed to obtain an Al plate with surface pretreatment.

[0045] The dimensions of the Al plate mentioned in step one are 100mm × 100mm × 4mm;

[0046] II. Arc spraying of Cu:

[0047] One side of the pretreated Al plate is subjected to arc spraying of Cu to obtain a Cu / Al substrate with a Cu coating.

[0048] The process of arc spraying Cu in step two is as follows: using Cu wire as the arc spraying material, the surface-pretreated Al plate is arc sprayed for 5 seconds under the conditions of a spraying distance of 150mm, a spraying voltage of 31V and a wire feeding speed of 50mm / s to obtain a Cu / Al substrate with a Cu coating; the specifications of the Cu wire are Φ2×1000mm.

[0049] III. Electrophoretic deposition of GO:

[0050] Electrophoretic deposition of GO was performed on a Cu / Al substrate with a Cu coating, followed by drying, to obtain a GO / Cu / Al preform with a GO deposition thin layer.

[0051] The electrophoretic deposition of GO in step two is as follows: a Cu / Al substrate with a Cu coating is immersed in a deposition solution, and deposition is carried out for 10 seconds under the conditions of 120V voltage and Cu coating facing the electrode plate. The substrate is then removed, dried, and a GO / Cu / Al prefabricated plate with a GO deposition thin layer is obtained. The deposition solution is a mixture of graphene, Al(NO3)3 and anhydrous ethanol, wherein the mass-volume ratio of graphene, Al(NO3)3 and anhydrous ethanol is 0.1g:400mL.

[0052] IV. Surface mechanical treatment:

[0053] A layer of graphene lubricating oil was coated on the surface of a GO / Cu / Al prefabricated plate with a GO deposition thin layer. The surface of the GO / Cu / Al prefabricated plate with a GO deposition thin layer was subjected to multiple pressure friction treatments under the conditions of applying a load of 500N in the direction perpendicular to the plate plane, a feed rate of 1mm / s in the direction parallel to the plate plane, and a pressure friction head rotation speed of 600rpm. The graphene and graphene lubricating oil on the surface of the prefabricated plate achieved self-lubrication during friction and were removed during the friction process, resulting in a copper-aluminum composite surface gradient nanostructure material.

[0054] The graphene lubricating oil mentioned in step four is a cooling lubricating oil with added graphene nanosheets. The amount of graphene nanosheets added is 0.1 g / L. The cooling lubricating oil was purchased from Mobil spindle oil No. 3.

[0055] The pressure friction treatment described in step four is performed twice.

[0056] Example 2: The difference between this example and Example 1 is that the arc spraying process for Cu in step two is as follows: using Cu wire as the arc spraying material, the pre-treated Al plate is arc sprayed for 7 seconds under the conditions of a spraying distance of 150mm, a spraying voltage of 37V, and a wire feeding speed of 50mm / s to obtain a Cu / Al substrate with a Cu coating; the specifications of the Cu wire are Φ2×1000mm. Other steps and parameters are the same as in Example 1.

[0057] Example 3: The difference between this example and Example 1 is that in step four, a layer of graphene lubricating oil is coated on the surface of the GO / Cu / Al prefabricated plate with a GO deposition thin layer. The surface of the GO / Cu / Al prefabricated plate with the GO deposition thin layer is subjected to multiple pressure friction treatments under the conditions of applying a load of 500N perpendicular to the plate plane, a feed rate of 0.5mm / s parallel to the plate plane, and a pressure friction head rotation speed of 300rpm. Other steps and parameters are the same as in Example 1.

[0058] Compared with Example 1: The difference between this embodiment and Example 1 is that step two, namely, arc spraying of Cu, is omitted. All other steps and parameters are the same as in Example 1.

[0059] Comparative Example 2: The difference between this embodiment and Example 1 is that step three, i.e., the electrophoretic deposition of GO, is omitted. All other steps and parameters are the same as in Example 1.

[0060] Comparing Example 3: The difference between this embodiment and Example 1 is that step four, i.e., the surface mechanical treatment, is omitted. All other steps and parameters are the same as in Example 1.

[0061] Figure 1The images show the chemical composition distribution and microstructure of the copper-aluminum composite surface gradient nanostructure material prepared in Example 1. In the image, (a) shows the Al and Cu element distribution on the surface by EDS scanning, (b) shows the Al and Cu element distribution on the cross section by EDS scanning, (c) shows the TEM image of the surface structure, and (d) shows the gradient TEM image of the cross section structure.

[0062] from Figure 1 It can be seen that Cu element is enriched from the surface to a certain depth from the surface. As the depth from the surface increases, Cu element decreases. Nanocrystals are formed on the surface of the material, and the grain size of the material increases with the depth from the surface.

[0063] Figure 2 This is a hardness gradient diagram of the copper-aluminum composite surface gradient nanostructure material prepared in Example 1;

[0064] from Figure 2 It can be seen that the microhardness gradually decreases with increasing depth from the surface and eventually drops to the hardness of the aluminum matrix, with the surface hardness reaching 128 HV.

[0065] The surface hardness, thermal conductivity, and electrical conductivity of the copper-aluminum composite surface gradient nanostructure materials and aluminum substrates prepared in Examples 1-3 and Comparative Examples 1-3 are listed in Table 1.

[0066] Table 1

[0067]

[0068] Table 1 shows that the surface hardness gradient of the copper-aluminum composite surface gradient nanostructure material can reach 70–130 HV, which is 2–4 times higher than that of the aluminum matrix; the thermal conductivity ranges from 275 to 315 W / (m·K), which is 17%–34% higher than that of the aluminum matrix; and the electrical conductivity ranges from 4.0 to 4.5 × 10⁻⁶. 7 The S / m ratio is increased by 14% to 29% compared to the aluminum matrix.

Claims

1. A method for preparing a copper-aluminum composite surface gradient nanostructure material, characterized in that... The preparation method is specifically carried out according to the following steps: I. Surface Pretreatment: First, the Al board is subjected to alkaline washing treatment, and then sandblasting treatment to obtain the Al board with surface pretreatment. II. Arc spraying of Cu: One or both sides of the pre-treated Al plate are subjected to arc spraying of Cu to obtain a Cu / Al substrate with Cu coating on one or both sides. III. Electrophoretic deposition of GO: A Cu / Al substrate with one or both sides coated with Cu is immersed in a deposition solution and deposited for 10 to 30 seconds under the conditions of a voltage of 100V to 150V and Cu coating facing the electrode plate. The substrate is then removed and dried to obtain a GO / Cu / Al preform with a GO deposition thin layer. The deposition solution is a mixture of graphene, Al(NO3)3 and anhydrous ethanol, wherein the mass-volume ratio of graphene, Al(NO3)3 and anhydrous ethanol is (0.2g~0.5g):(0.05g~0.2g):400mL; IV. Surface mechanical treatment: A layer of graphene lubricating oil was coated on the surface of a GO / Cu / Al prefabricated plate with a GO deposition thin layer. The surface of the GO / Cu / Al prefabricated plate with a GO deposition thin layer was subjected to multiple pressure friction treatments under the conditions of applying a load of 300~700N in the direction perpendicular to the plate plane, a feed rate of 0.1~3mm / s in the direction parallel to the plate plane, and a pressure friction head rotation speed of 0~900rpm. The graphene and graphene lubricating oil on the surface of the prefabricated plate achieved self-lubrication during friction and were removed during the friction process, resulting in a copper-aluminum composite surface gradient nanostructure material.

2. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The thickness of the Al plate mentioned in step one is 1mm to 10mm.

3. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The alkaline washing process described in step one is as follows: the Al plate is immersed in a 5% NaOH solution for 5 to 10 seconds, then rinsed with water until neutral, and then dried to obtain the alkaline-washed Al plate.

4. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The sandblasting process described in step one is as follows: using Al2O3 particles as the abrasive, with a compressed air pressure of 0.2MPa~0.6MPa, a spray distance of 100mm~300mm, and a spray angle of 45°. o Under certain conditions, the Al plate after alkaline washing is sandblasted for 10s~60s to remove residual particles on the surface, thus obtaining the Al plate after surface pretreatment.

5. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The process of arc spraying Cu treatment described in step two is as follows: using Cu wire as the arc spraying material, the surface-pretreated Al plate is arc sprayed for 2s to 15s under the conditions of a spraying distance of 100mm to 200mm, a spraying voltage of 20V to 40V, and a wire feeding speed of 30mm / s to 80mm / s to obtain a Cu / Al substrate with a Cu coating on one or both sides.

6. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The pressure friction treatment described in step four is performed 1 to 100 times.

7. The method for preparing a copper-aluminum composite surface gradient nanostructure material according to claim 1, characterized in that... The graphene lubricating oil mentioned in step four is a cooling lubricating oil with added graphene nanosheets, and the amount of graphene nanosheets added is 0.1g / L~0.3g / L.

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