A high-strength aluminum alloy for electrical applications and its smelting process

Abstract

This application relates to the technical field of aluminum alloys, and in particular to a high-strength electrical aluminum alloy and its smelting process. The aluminum alloy comprises an aluminum alloy matrix and a grain inhibitor. The amount of grain inhibitor added is 0.08-0.16% of the weight of the aluminum alloy matrix. The weight percentage of each chemical component of the aluminum alloy matrix is ​​as follows: Fe 0.6-0.85%, Mg 0.7-0.9%, Si 0.05-0.09%, Cu 0.3-0.5%, Re 0.12-0.22%, B 0.02-0.06%, with the balance being Al. The grain inhibitor is prepared by treating a metal carbide mixture with a cationic surfactant, loading graphene oxide, and then reducing the graphene oxide with hydrazine hydrate. The metal carbide mixture is a mixture of titanium carbide, vanadium carbide, and tantalum carbide. It has the advantages of improving the electrical conductivity and strength of the electrical aluminum alloy.

Description

Technical Field

[0001] This application relates to the technical field of aluminum alloys, and in particular to a high-strength electrical aluminum alloy and its smelting process. Background Technology

[0002] Currently, aluminum alloys for electrical applications are widely used in the power industry and electronics. These alloys require high electrical conductivity, corrosion resistance, and mechanical strength. Traditional smelting processes for their preparation are hampered by raw material costs, energy consumption, and environmental pollution, making it difficult to balance high performance with low cost. Key challenges include high energy consumption in traditional smelting processes and uneven alloy element distribution leading to significant fluctuations in material properties. Existing improvements typically focus on optimizing composition design and smelting conditions, such as introducing rare earth metals to improve grain structure, but these increase costs and environmental pressures. While these methods can improve alloy performance to some extent, they still fail to completely resolve the issue of alloy element segregation during heat treatment, thus failing to fully meet the stringent requirements of the modern electrical industry. Summary of the Invention

[0003] In order to improve the electrical conductivity and strength of aluminum alloys for electrical applications, this application provides a high-strength aluminum alloy for electrical applications and its smelting process.

[0004] In the first aspect, this application provides a high-strength aluminum alloy for electrical applications, employing the following technical solution:

[0005] A high-strength aluminum alloy for electrical applications includes an aluminum alloy matrix and a grain inhibitor, wherein the amount of grain inhibitor added is 0.08-0.16% of the weight of the aluminum alloy matrix;

[0006] The weight percentages of each chemical component in the aluminum alloy matrix are as follows: Fe 0.6-0.85%, Mg 0.7-0.9%, Si 0.05-0.09%, Cu 0.3-0.5%, RE 0.12-0.22%, B 0.02-0.06%, with the balance being Al;

[0007] The grain inhibitor is prepared by treating a mixture of metal carbides with a cationic surfactant, loading graphene oxide onto the mixture, and then reducing the graphene oxide with hydrazine hydrate; the metal carbide mixture is a mixture of titanium carbide, vanadium carbide, and tantalum carbide.

[0008] By employing the above technical solution, a grain inhibitor is compounded and then graphene oxide is loaded onto its surface. Graphene oxide has a two-dimensional sheet structure, which is reduced by hydrazine hydrate to obtain the graphene structure. Graphene has high thermal stability and is not easily decomposed at high temperatures. After the grain inhibitor is added to the aluminum alloy, the graphene on its surface can combine with the metal atoms in the aluminum alloy due to the electron cloud effect, mainly forming an Al-GO interface layer. This can greatly reduce the interfacial tension between the grain inhibitor and the aluminum alloy system, significantly improve the dispersibility and compatibility of the grain inhibitor in the aluminum alloy system, and the grain inhibitor can still play its role in reducing the grain fineness of the aluminum alloy. Furthermore, the electron cloud effect of graphene can improve the conductivity of the aluminum alloy to a certain extent. Therefore, by adding the grain inhibitor prepared in this application, the aluminum alloy can be improved in terms of both conductivity and strength.

[0009] Preferably, the weight ratio of titanium carbide, vanadium carbide and tantalum carbide is 10:3:(0-1).

[0010] By adopting the above technical solution, the aluminum alloy prepared by combining titanium carbide, vanadium carbide and tantalum carbide in this ratio as grain inhibitors has better performance.

[0011] Preferably, the amount of grain inhibitor added is 0.12% of the weight of the aluminum alloy matrix.

[0012] By adopting the above technical solution and exploring the amount of grain inhibitor added, it was found that when the amount added is 0.12% of the weight of the aluminum alloy matrix, the overall cost of the aluminum alloy is better. When the amount added is further increased, the increase in strength is small.

[0013] Preferably, the cationic surfactant is a quaternary ammonium salt cationic surfactant.

[0014] By adopting the above technical solution, the surface of the metal carbide is charged by a surfactant, and graphene oxide is loaded onto the metal carbide by electrostatic attraction.

[0015] Preferably, the titanium carbide has an average particle size of 40 nm, the vanadium carbide has an average particle size of 500 nm, and the tantalum carbide has an average particle size of 200 nm.

[0016] Preferably, the aluminum alloy further includes a compatibilizer, wherein the amount of the compatibilizer added is 1.2-1.7% of the weight of the aluminum alloy matrix.

[0017] By adopting the above technical solution and adding compatibilizers, the compatibility between grain inhibitors and raw materials can be improved, further enhancing the overall strength and uniformity of aluminum alloys, and achieving a product qualification rate of over 99%.

[0018] Preferably, the compatibilizer is a mixture of nickel powder and cobalt powder.

[0019] By adopting the above technical solution, when nickel powder and cobalt powder are added simultaneously as compatibilizers, the strength of the resulting aluminum alloy is superior to that of aluminum alloys with only one of them added.

[0020] Preferably, the weight ratio of the nickel powder to the cobalt powder is 2:1.

[0021] By adopting the above technical solution, this ratio is the preferred choice.

[0022] Secondly, this application provides a smelting process for high-strength electrical aluminum alloys, employing the following technical solution:

[0023] A smelting process for a high-strength electrical aluminum alloy includes the following steps:

[0024] S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys containing RE, and aluminum-boron master alloys, and then mix them according to the weight percentage of each chemical component in the aluminum alloy matrix.

[0025] S2. Set the furnace temperature to 800-870℃, add aluminum ingots, and when the aluminum ingots have melted to 70-80%, add a covering agent. After the aluminum ingots have completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy, and aluminum-boron master alloy in sequence. After the materials are added, hold the furnace at 740-770℃, and use argon to blow in a refining agent for refining and slag removal. Then perform pre-furnace composition analysis. Then add raw materials other than the aluminum alloy matrix.

[0026] S4. After refining and slag removal, ingots are cast. The ingot casting process parameters are as follows: inlet water temperature 20-25℃, outlet water temperature 30-35℃, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10℃.

[0027] S5. Homogenize the ingot in a heating furnace at a temperature of 575-595℃ for 10-15 hours, and then let it cool naturally.

[0028] S6. Tempering the ingot: Continue to heat the ingot evenly in the heating furnace to 380-420℃, and then cool it naturally to obtain aluminum alloy.

[0029] By adopting the above technical solution, and by adjusting the order of adding raw materials in the smelting process and setting the process parameters, the grain size of the aluminum alloy is made smaller, the compatibility of the raw materials inside the aluminum alloy is better, and the content of internal bubbles is greatly reduced, thereby producing an aluminum alloy with better conductivity and strength.

[0030] In summary, this application includes at least one of the following beneficial technical effects:

[0031] 1. By compounding a grain inhibitor and then loading graphene oxide onto its surface, graphene oxide, a two-dimensional sheet structure, is obtained after reduction with hydrazine hydrate. Graphene exhibits high thermal stability and is not easily decomposed at high temperatures. When the grain inhibitor is added to the aluminum alloy, the graphene on its surface, due to its electron cloud effect, can combine with metal atoms in the aluminum alloy, mainly forming an Al-GO interface layer. This significantly reduces the interfacial tension between the grain inhibitor and the aluminum alloy system, greatly improving the dispersion and compatibility of the grain inhibitor within the aluminum alloy system, while still maintaining its function of reducing the grain fineness of the aluminum alloy. Furthermore, the electron cloud effect of graphene can improve the conductivity of the aluminum alloy to a certain extent. Therefore, by adding the grain inhibitor prepared in this application, the aluminum alloy can be improved in terms of both conductivity and strength.

[0032] 2. The conductivity of the aluminum alloys prepared in this application is between 56.8% and 57.6% IACS, and their tensile strength is between 246% and 279 MPa. This indicates that the aluminum alloys prepared in this application have both high strength and high conductivity, and have great application potential in the field of electrical aluminum alloys. Detailed Implementation

[0033] The following provides a more detailed description of this application in conjunction with specific details.

[0034] raw material

[0035] All raw materials used in this application were purchased commercially. Specifically, the covering agent and refining agent were purchased from Jiangxi Century Xing New Materials Co., Ltd.; the aluminum ingot grade was A199.7E, and all intermediate alloys were purchased from Xuzhou Jinlong Metal Aluminum Co., Ltd.; the chemical composition of the rare earth intermediate alloy is as follows:

[0036]

[0037] The parameters for the remaining intermediate alloys are as follows:

[0038]

[0039] Preparation Example 1

[0040] A grain inhibitor, the preparation method of which is as follows:

[0041] S1. Prepare a surfactant solution with a concentration of 2 g / L. The surfactant is a cationic surfactant, and the cationic surfactant is a quaternary ammonium salt cationic surfactant with CAS number 61791-10-4.

[0042] S2. Titanium carbide, vanadium carbide, and tantalum carbide are mixed in a weight ratio of 10:3:1. This mixture is dispersed in three times its weight of the surfactant solution prepared in S1. The mixture is stirred for 20 minutes, filtered, and the precipitate is dried to obtain a surface-modified metal carbide mixture. The average particle size of titanium carbide is 40 nm; the average particle size of vanadium carbide is 500 nm; and the average particle size of tantalum carbide is 200 nm.

[0043] S3. Prepare a 1.5 g / L graphene oxide aqueous dispersion and enhance dispersion by ultrasound. Then add a quarter of the weight of the graphene oxide aqueous dispersion and a surface-modified metal carbide mixture. Stir for 10 min, then add hydrazine hydrate to make the concentration of hydrazine hydrate 1.2 g / L. Then raise the temperature to 90 °C and stir for 2 h. Then filter and dry the precipitate to obtain the crystallite inhibitor.

[0044] Example 1

[0045] A high-strength aluminum alloy for electrical applications comprises an aluminum alloy matrix, grain inhibitors, and compatibilizers. The weight percentage of each chemical component in the aluminum alloy matrix is ​​shown in Table 1. The smelting process of this high-strength aluminum alloy for electrical applications is as follows:

[0046] S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys, and aluminum-boron master alloys, and then mix them according to the weight percentage of each chemical component of the aluminum alloy matrix in Table 1.

[0047] S2. Before production, perform a furnace cleaning process to remove all debris from the melting furnace. After cleaning, wash the furnace once with 99.7% E aluminum.

[0048] S3. Set the furnace temperature of the melting furnace to 850℃, add aluminum ingots, and when the aluminum ingots have melted to 70-80%, add a covering agent. After the aluminum ingots have completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy, and aluminum-boron master alloy in sequence. Among them, aluminum-boron master alloy and rare earth master alloy are added in the trough, and the remaining raw materials are added in the melting furnace. After the batching is completed, keep the temperature at 760℃, and use high-purity argon to blow in the refining agent for refining and slag removal for no less than 15 minutes to ensure uniformity and avoid causing the aluminum liquid to roll.

[0049] After refining for 60 minutes, the furnace temperature was controlled at 725℃. After standing for 15 minutes, slag was removed, and a rapid pre-furnace composition analysis was performed. The composition was adjusted according to the analysis results until it met the requirements. Then, grain inhibitors and compatibilizers were added. The amount of grain inhibitor added was 0.12% of the weight of the aluminum alloy matrix, and the amount of compatibilizer added was 1.5% of the weight of the aluminum alloy matrix. The grain inhibitor was from Preparation Example 1. The compatibilizer was a mixture of nickel powder and cobalt powder in a weight ratio of 2:1. The particle size of the nickel powder was 80 nm, and the particle size of the cobalt powder was 50 nm.

[0050] S4. After refining and slag removal, ingots are cast. The ingot casting process parameters are as follows: inlet water temperature 20-25℃, outlet water temperature 30-35℃, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10℃. During the ingot casting process, the flow channel, flow plate, and liquid level in the crystallizer should be controlled to prevent fluctuations. At the beginning, the bottom slag should be removed, and the slag around the perimeter should be removed first, followed by the center. The height of the flow plate should be adjusted so that the liquid level is higher than the funnel opening, and the liquid level should be controlled to be 70-80 mm away from the upper edge of the crystallizer.

[0051] S5. Homogenize the ingot in a heating furnace at 585℃ for 13 hours, and then let it cool naturally.

[0052] S6. Tempering the ingot: Continue to heat the ingot evenly in the heating furnace to 400℃ at a heating rate of 50℃ / h, and then cool it naturally to obtain aluminum alloy.

[0053] Table 1. Weight percentage (%) of each chemical component in the aluminum alloy matrix of Example 1

[0054]

[0055] Example 2

[0056] A high-strength electrical aluminum alloy differs from Example 1 in that the nickel powder in its compatibilizer is replaced with an equal mass of cobalt powder, while the other raw materials are the same as in Example 1.

[0057] Example 3

[0058] A high-strength electrical aluminum alloy differs from Example 1 in that the cobalt powder in its compatibilizer is replaced with an equal mass of nickel powder, while the other raw materials are the same as in Example 1.

[0059] Example 4

[0060] A high-strength electrical aluminum alloy differs from Example 1 in that its compatibilizer is replaced with an equal mass of aluminum ingots, while the other raw materials are the same as in Example 1.

[0061] Example 5

[0062] A high-strength electrical aluminum alloy differs from Example 1 in that the amount of grain inhibitor added is 0.08% of the weight of the aluminum alloy matrix, while the other raw materials are the same as in Example 1.

[0063] Example 6

[0064] A high-strength electrical aluminum alloy differs from Example 1 in that the amount of grain inhibitor added is 0.16% of the weight of the aluminum alloy matrix, while the other raw materials are the same as in Example 1.

[0065] Example 7

[0066] A high-strength electrical aluminum alloy differs from Example 1 in that its grain inhibitor is not prepared with tantalum carbide, while the other raw materials are the same as in Example 1.

[0067] Comparative Example 1

[0068] A high-strength electrical aluminum alloy differs from Example 1 in that its grain inhibitor is replaced with an equal mass of aluminum ingots, while the other raw materials are the same as in Example 1.

[0069] Comparative Example 2

[0070] A high-strength electrical aluminum alloy differs from Example 1 in that its grain inhibitor is not loaded with graphene oxide on its surface; that is, the grain inhibitor is replaced by a mixture of equal masses of titanium carbide, vanadium carbide, and tantalum carbide, with a weight ratio of 10:3:1. The remaining raw materials are the same as in Example 1.

[0071] Performance testing

[0072] Detection methods / test methods

[0073] High-strength electrical aluminum alloys were prepared according to Examples 1-7 and Comparative Examples 1-2, and then tested according to the following testing methods. The test results are shown in Table 2.

[0074] Conductivity and tensile strength: Tested according to the test method in GB / T 31840, each sample was tested 3 times and the average value was taken; among them, conductivity was calculated from the measured resistivity.

[0075] Table 2. Detection results of Examples 1-7 and Comparative Examples 1-2

[0076]

[0077] The test data from Examples 1-7, Comparative Examples 1-2, and Table 2 show that the conductivity of the aluminum alloys prepared in this application is between 56.8% and 57.6% IACS, while their tensile strength is between 246% and 279 MPa. This indicates that the aluminum alloys prepared in this application have both high strength and high conductivity, and have great application potential in the field of electrical aluminum alloys.

[0078] By compounding a grain inhibitor and then loading graphene oxide onto its surface, the graphene oxide, a two-dimensional sheet structure, is reduced to graphene structure by hydrazine hydrate. Graphene has high thermal stability and is not easily decomposed at high temperatures. After adding the grain inhibitor to the aluminum alloy, the graphene on its surface, due to its electron cloud effect, can combine with the metal atoms in the aluminum alloy, mainly forming an Al-GO interface layer. This significantly reduces the interfacial tension between the grain inhibitor and the aluminum alloy system, greatly improving the dispersion and compatibility of the grain inhibitor within the aluminum alloy system, while still maintaining its function of reducing the grain fineness of the aluminum alloy. Furthermore, the electron cloud effect of graphene can improve the conductivity of the aluminum alloy to a certain extent. Therefore, by adding the grain inhibitor prepared in this application, the aluminum alloy can be improved in terms of both conductivity and strength. This can be verified through Example 1 and Comparative Examples 1-2. Based on this, and in conjunction with Examples 5-6, the study investigated the amount of grain inhibitor added. It was found that when the addition amount was 0.12% of the aluminum alloy matrix, the overall cost of the aluminum alloy was optimal. Further increases in the addition amount resulted in only a small increase in strength. Furthermore, aluminum alloys prepared using a composite of titanium carbide, vanadium carbide, and tantalum carbide as grain inhibitors exhibited superior performance.

[0079] Based on this, by adding compatibilizers, the grain inhibitors and the compatibility between various raw materials can be improved, further enhancing the overall strength and uniformity of the aluminum alloy, and achieving a product qualification rate of over 99%. This can be verified by the test results of Examples 1-4.

[0080] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A high-strength aluminum alloy for electrical applications, characterized in that: It comprises an aluminum alloy matrix and a grain inhibitor, wherein the amount of grain inhibitor added is 0.08-0.16% of the weight of the aluminum alloy matrix; The weight percentages of each chemical component in the aluminum alloy matrix are as follows: Fe 0.6-0.85%, Mg 0.7-0.9%, Si 0.05-0.09%, Cu 0.3-0.5%, RE 0.12-0.22%, B 0.02-0.06%, with the balance being Al; The grain inhibitor is prepared by treating a mixture of metal carbides with a cationic surfactant, loading graphene oxide onto the mixture, and then reducing the graphene oxide with hydrazine hydrate; the metal carbide mixture is a mixture of titanium carbide, vanadium carbide, and tantalum carbide.

2. The high-strength electrical aluminum alloy according to claim 1, characterized in that: The weight ratio of titanium carbide, vanadium carbide and tantalum carbide is 10:3:(0-1).

3. The high-strength electrical aluminum alloy according to claim 1, characterized in that: The amount of grain inhibitor added is 0.12% of the weight of the aluminum alloy matrix.

4. The high-strength electrical aluminum alloy according to claim 1, characterized in that: The cationic surfactant is a quaternary ammonium salt cationic surfactant.

5. A high-strength electrical aluminum alloy according to claim 1, characterized in that: The titanium carbide has an average particle size of 40 nm, the vanadium carbide has an average particle size of 500 nm, and the tantalum carbide has an average particle size of 200 nm.

6. A high-strength electrical aluminum alloy according to claim 1, characterized in that: The aluminum alloy also includes a compatibilizer, the amount of which is 1.2-1.7% of the weight of the aluminum alloy matrix, and the compatibilizer is a mixture of nickel powder and cobalt powder.

7. A high-strength electrical aluminum alloy according to claim 6, characterized in that: The weight ratio of the nickel powder to the cobalt powder is 2:

1.

8. A smelting process for a high-strength electrical aluminum alloy according to any one of claims 1-7, characterized in that: It includes the following steps: S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys containing RE, and aluminum-boron master alloys, and then mix them according to the weight percentage of each chemical component in the aluminum alloy matrix. S2. Set the furnace temperature to 800-870℃, add aluminum ingots, and when the aluminum ingots have melted to 70-80%, add a covering agent. After the aluminum ingots have completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy, and aluminum-boron master alloy in sequence. After the materials are added, hold the furnace at 740-770℃, and use argon to blow in a refining agent for refining and slag removal. Then perform pre-furnace composition analysis. Then add raw materials other than the aluminum alloy matrix. S4. After refining and slag removal, ingots are cast. The ingot casting process parameters are as follows: inlet water temperature 20-25℃, outlet water temperature 30-35℃, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10℃. S5. Homogenize the ingot in a heating furnace at a temperature of 575-595℃ for 10-15 hours, and then allow it to cool naturally. S6. Tempering the ingot: Continue to heat the ingot evenly in the heating furnace to 380-420℃, and then cool it naturally to obtain aluminum alloy.

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