Aluminum alloy profile for new energy vehicles

Abstract

This invention discloses an aluminum alloy profile for new energy vehicles, belonging to the field of new energy materials technology. The aluminum alloy profile of this invention, by mass percentage, comprises the following components: Fe 0.14-0.19%, Si 0.58-0.66%, Mg 0.6-1.3%, Cu 0.25-0.35%, Mn 0.07-0.15%, Cr 0.14-0.22%, Zn 0.01-0.05%, Ti 0.03-0.15%, composite rare earth metal elements 0.6-0.9%, with the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%. This invention optimizes the aluminum alloy profile from two perspectives: elemental composition and surface treatment. The addition of rare earth metal elements La, Pr, and Gd with different atomic radii and transformative abilities effectively refines the grain size of the aluminum alloy. Subsequent spraying of a surface treatment agent effectively improves the mechanical properties and corrosion resistance of the aluminum alloy profile.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials technology, specifically relating to an aluminum alloy profile for new energy vehicles. Background Technology

[0002] With the development of automotive technology and the increasing environmental awareness of people, the pollution caused by exhaust fumes from traditional gasoline-powered vehicles has received high attention from countries around the world. New energy vehicles have entered a period of rapid development in recent years and have gained increasing acceptance from consumers. Compared to traditional gasoline-powered vehicles, the fuel cell stack in new energy vehicles (taking electric vehicles as an example) weighs hundreds of kilograms, which places higher demands on the lightweighting of new energy vehicles.

[0003] Replacing traditional sheet metal materials with lightweight materials to reduce vehicle weight is one of the mainstream solutions for improving vehicle range. Suitable materials for automotive lightweighting generally include aluminum alloys, magnesium alloys, high-strength steel, and composite materials. Aluminum resources are abundant on Earth and are an important non-ferrous metal. Aluminum alloys, produced by adding other elements to pure aluminum, balance cost, performance, and lightweighting, making them a popular application area for lightweight components.

[0004] Existing aluminum alloy profiles often lack one or more of the required properties, such as tensile strength, yield strength, and corrosion resistance, making it difficult to meet the actual usage requirements of electric vehicles and their components. Chinese patent application CN201811558425.9 discloses a high-strength aluminum alloy profile for new energy vehicle battery trays and its preparation method. By improving the ingredient composition and employing a gradient heating process—that is, gradually decreasing the temperature of the preheated aluminum rod along its axis from front to back to create a temperature gradient—isothermal extrusion is achieved. This results in a product with uniform core surface temperature, bright surface color, and minimal deviation in mechanical properties after heating and processing. Furthermore, the aluminum alloy profile prepared by this method achieves a tensile strength exceeding 310 MPa and a yield strength of 270 MPa, thus improving product quality and consequently enhancing the overall quality of new energy vehicles.

[0005] However, the mechanical properties of current aluminum alloy materials cannot meet the latest high-strength and high-corrosion-resistance requirements in the field of new energy vehicles. How to develop an aluminum alloy profile with excellent comprehensive performance is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by optimizing the elemental composition and applying corrosion inhibitors, thereby significantly improving the mechanical properties and corrosion resistance of aluminum alloy materials. It is suitable for use in various parts of new energy vehicles and has broad application prospects.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] An aluminum alloy profile for new energy vehicles comprises, by weight percentage: Fe 0.14-0.19%, Si 0.58-0.66%, Mg 0.6-1.3%, Cu 0.25-0.35%, Mn 0.07-0.15%, Cr 0.14-0.22%, Zn 0.01-0.05%, Ti 0.03-0.15%, composite rare earth metal elements 0.6-0.9%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0009] Furthermore, the composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:1:1.

[0010] A method for preparing aluminum alloy profiles for new energy vehicles includes the following preparation steps:

[0011] (1) Smelting: Prepare raw materials of various metal elements in proportion, melt aluminum ingots, add other metal elements, heat and melt, stir evenly to obtain alloy melt;

[0012] (2) Refining treatment: The alloy melt obtained in step (1) is refined to complete degassing and impurity removal;

[0013] (3) Casting: The refined melt is cast into aluminum alloy ingots at a casting temperature of 700-750℃ and a casting speed of 30-50mm / min.

[0014] (4) Homogenization treatment: The aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment. The homogenization treatment temperature is 540-560℃ and the holding time is 5-10h.

[0015] (5) Cooling treatment: Cool the homogenized aluminum alloy ingot to 150-180℃ at a cooling rate of 100-120℃ / hour, and then cool it to room temperature with water mist.

[0016] (6) Forming: The cooled aluminum alloy ingot is fed into an extrusion press for extrusion forming. The extrusion temperature is 475-485℃, the extrusion rate is 10-12m / min, and the extrusion pressure is 120-150MPa.

[0017] (7) Quenching and cooling: Quench and cool the extruded material to room temperature. The quenching temperature is 455-465℃, and the temperature is held for 3-4 hours. Then, cool it to room temperature with water.

[0018] (8) Artificial aging: The quenched and cooled profiles are artificially aged at a temperature of 190-200℃ for 5-7 hours, and then cooled to room temperature.

[0019] (9) Surface anti-corrosion treatment: Spray the surface treatment agent onto the profile surface, cure at 170℃ for 30 minutes after spraying, and then let it cool naturally.

[0020] Furthermore, in step (1), the melting temperature is 740-750℃ and the melting time is 5-7h.

[0021] Furthermore, the refining method in step (2) is as follows: argon gas is used to blow refining agent into the molten aluminum formed by melting for in-furnace refining. The amount of refining agent is 1.5-2.5% of the weight of the alloy melt, and the in-furnace refining time is 17-20 min.

[0022] Further, in step (9), the surface treatment agent is a silica sol solution of corrosion inhibitor. The specific preparation method is as follows: 0.1 mmol of 2,5-furandicarboxylic acid and 0.1 mmol of cerium nitrate are added sequentially to 5 ml of mixed solvent. The mixed solvent consists of N,N-dimethylacetamide, ethanol and deionized water in a volume ratio of 1:1:1. After ultrasonic treatment of the mixed solution for 15 min, it is transferred to a reaction vessel and reacted at 95 °C for 48 h. After cooling to room temperature and drying, the corrosion inhibitor is obtained. Take nano silica sol, add 1-3% of the corrosion inhibitor by mass of nano silica sol under ultrasonication, disperse it evenly, adjust the pH of the system to 4.5-5.5, and then add 10-15% of methyltrimethoxysilane by mass of nano silica sol. Mix and react at room temperature for 8 h to obtain the surface treatment agent.

[0023] Furthermore, the nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 20-50%.

[0024] Furthermore, the surface treatment agent is sprayed to a thickness of 1-3 μm.

[0025] Beneficial effects:

[0026] (1) This invention optimizes aluminum alloy profiles from two perspectives: elemental composition and surface treatment, aiming to improve the mechanical properties and corrosion resistance of aluminum alloy profiles. On the one hand, this invention adds rare earth metal elements La, Pr, and Gd with different atomic radii and qualitative transformation capabilities. After the three are mixed in equal proportions, they exhibit a significant synergistic effect, effectively refining the grains of the aluminum alloy. The refined grains tend to be evenly distributed and dispersed in the aluminum matrix, playing a role in dispersion strengthening and grain refinement strengthening, thereby effectively improving the strength of the material. At the same time, rare earth metal elements La, Pr, and Gd have strong degassing and impurity removal effects, helping to remove harmful impurities in aluminum and aluminum alloys, such as hydrogen, oxygen, and sulfur, further refining the grains or changing their morphology. Meanwhile, the refined microstructure can effectively hinder crack propagation and grain boundary sliding during the corrosion process, improving the corrosion resistance of the material.

[0027] (2) Secondly, the present invention includes refining and homogenization treatments. The refining treatment can effectively remove hydrogen and various harmful impurities, prevent the formation of porosity and inclusions during casting, and improve the mechanical properties of aluminum alloy profiles. The homogenization treatment can effectively reduce and eliminate intragranular segregation, improve the surface quality of the finished aluminum alloy profiles, and make the finished profiles smooth without obvious streaks and particles. Furthermore, the rapid cooling treatment after the homogenization treatment can make the precipitates dispersed in a fine shape, which is conducive to refining the grains and improving the tensile strength and yield strength of the finished aluminum alloy profiles.

[0028] (3) For the surface anti-corrosion treatment of the formed profile, this invention uses dipentafuran dicarboxylic acid as an organic ligand and Ce ions as metal cation centers. A solvothermal method is used to prepare the corrosion inhibitor, which is then dispersed in a modified silica sol prepared by copolymerization of methyltrimethoxysilane as a monomer and nano-SiO2 sol. After being sprayed onto the aluminum alloy surface, it has good adhesion to the aluminum alloy substrate and can continuously and effectively play an anti-corrosion role. At the same time, the presence of nano-silica particles can effectively fill the micropores on the aluminum alloy surface, improve the surface smoothness of the material, and significantly improve the coating strength and the wear resistance of the aluminum alloy surface. The resulting aluminum alloy profile has excellent mechanical properties and strong corrosion resistance, and is particularly suitable for use in parts with anti-corrosion requirements such as new energy vehicle motor batteries. Attached Figure Description

[0029] Figure 1 The images show the grain morphology of the profiles obtained in the examples and comparative examples. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0031] Example 1

[0032] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, composite rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0033] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:1:1.

[0034] A method for preparing aluminum alloy profiles for new energy vehicles includes the following preparation steps:

[0035] (1) Smelting: Prepare raw materials of various metal elements in proportion, melt aluminum ingots, add other metal elements, heat and melt, stir evenly to obtain alloy melt;

[0036] (2) Refining treatment: The alloy melt obtained in step (1) is refined to complete degassing and impurity removal;

[0037] (3) Casting: The refined melt is cast into aluminum alloy ingots at a casting temperature of 700-750℃ and a casting speed of 30mm / min.

[0038] (4) Homogenization treatment: The aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment. The homogenization treatment temperature is 540-560℃ and the holding time is 5h.

[0039] (5) Cooling treatment: Cool the homogenized aluminum alloy ingot to 150-180℃ at a cooling rate of 100-120℃ / hour, and then cool it to room temperature with water mist.

[0040] (6) Forming: The cooled aluminum alloy ingot is fed into the extrusion press for extrusion forming. The extrusion temperature is 475-485℃, the extrusion speed is 10m / min, and the extrusion pressure is 120MPa.

[0041] (7) Quenching and cooling: Quench and cool the extruded material to room temperature. The quenching temperature is 455-465℃, and the temperature is held for 3 hours. Then, cool it to room temperature with water.

[0042] (8) Artificial aging: The quenched and cooled profiles are artificially aged at a temperature of 190-200℃ for 5 hours, and then cooled to room temperature.

[0043] (9) Surface anti-corrosion treatment: Spray the surface treatment agent onto the profile surface, cure at 170℃ for 30 minutes after spraying, and then let it cool naturally.

[0044] Step (1) The melting temperature is 740-750℃ and the melting time is 5h.

[0045] The refining method in step (2) is as follows: Argon gas is used to blow refining agent into the molten aluminum to carry out in-furnace refining. The amount of refining agent is 1.5% of the weight of the alloy melt, and the in-furnace refining time is 17 minutes.

[0046] Step (9) The surface treatment agent is a silica sol solution with corrosion inhibitor. The specific preparation method is as follows: 0.1 mmol of 2,5-furandicarboxylic acid and 0.1 mmol of cerium nitrate are added sequentially to 5 ml of mixed solvent. The mixed solvent consists of N,N-dimethylacetamide, ethanol and deionized water in a volume ratio of 1:1:1. After ultrasonic treatment of the mixed solution for 15 min, it is transferred to a reaction vessel and reacted at 95℃ for 48 h. After cooling to room temperature and drying, the corrosion inhibitor is obtained. Take nano silica sol, add 1-3% of the corrosion inhibitor by mass of nano silica sol under ultrasonication, disperse it evenly, adjust the pH of the system to 4.5-5.5, and then add 10% of methyltrimethoxysilane by mass of nano silica sol. Mix and react at room temperature for 8 h to obtain the surface treatment agent.

[0047] The nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 20%.

[0048] The surface treatment agent is sprayed to a thickness of 1-3 μm.

[0049] Example 2

[0050] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.16%, Si 0.62%, Mg 1%, Cu 0.3%, Mn 0.1%, Cr 0.2%, Zn 0.03%, Ti 0.1%, composite rare earth metal elements 0.75%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0051] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:1:1.

[0052] A method for preparing aluminum alloy profiles for new energy vehicles includes the following preparation steps:

[0053] (1) Smelting: Prepare raw materials of various metal elements in proportion, melt aluminum ingots, add other metal elements, heat and melt, stir evenly to obtain alloy melt;

[0054] (2) Refining treatment: The alloy melt obtained in step (1) is refined to complete degassing and impurity removal;

[0055] (3) Casting: The refined melt is cast into aluminum alloy ingots at a casting temperature of 700-750℃ and a casting speed of 40mm / min.

[0056] (4) Homogenization treatment: The aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment. The homogenization treatment temperature is 540-560℃ and the holding time is 8h.

[0057] (5) Cooling treatment: Cool the homogenized aluminum alloy ingot to 150-180℃ at a cooling rate of 100-120℃ / hour, and then cool it to room temperature with water mist.

[0058] (6) Forming: The cooled aluminum alloy ingot is fed into the extrusion press for extrusion forming. The extrusion temperature is 475-485℃, the extrusion rate is 12m / min, and the extrusion pressure is 130MPa.

[0059] (7) Quenching and cooling: Quench and cool the extruded material to room temperature. The quenching temperature is 455-465℃, and the temperature is held for 3 hours. Then, cool it to room temperature with water.

[0060] (8) Artificial aging: The quenched and cooled profiles are artificially aged at a temperature of 190-200℃ for 6 hours, and then cooled to room temperature.

[0061] (9) Surface anti-corrosion treatment: Spray the surface treatment agent onto the profile surface, cure at 170℃ for 30 minutes after spraying, and then let it cool naturally.

[0062] Step (1) The melting temperature is 740-750℃ and the melting time is 6h.

[0063] The refining method in step (2) is as follows: Argon gas is used to blow refining agent into the molten aluminum to carry out in-furnace refining. The amount of refining agent is 2% of the weight of the alloy melt, and the in-furnace refining time is 20 minutes.

[0064] Step (9) The surface treatment agent is a silica sol solution with corrosion inhibitor. The specific preparation method is as follows: 0.1 mmol of 2,5-furandicarboxylic acid and 0.1 mmol of cerium nitrate are added sequentially to 5 ml of mixed solvent. The mixed solvent consists of N,N-dimethylacetamide, ethanol and deionized water in a volume ratio of 1:1:1. After ultrasonic treatment of the mixed solution for 15 min, it is transferred to a reaction vessel and reacted at 95℃ for 48 h. After cooling to room temperature and drying, the corrosion inhibitor is obtained. Take nano silica sol, add 1-3% of the corrosion inhibitor by mass of nano silica sol under ultrasonication, disperse it evenly, adjust the pH of the system to 4.5-5.5, and then add 12% of methyltrimethoxysilane by mass of nano silica sol. Mix and react at room temperature for 8 h to obtain the surface treatment agent.

[0065] The nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 30%.

[0066] The surface treatment agent is sprayed to a thickness of 1-3 μm.

[0067] Example 3

[0068] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.19%, Si 0.66%, Mg 1.3%, Cu 0.35%, Mn 0.15%, Cr 0.22%, Zn 0.05%, Ti 0.15%, composite rare earth metal elements 0.9%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0069] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:1:1.

[0070] A method for preparing aluminum alloy profiles for new energy vehicles includes the following preparation steps:

[0071] (1) Smelting: Prepare raw materials of various metal elements in proportion, melt aluminum ingots, add other metal elements, heat and melt, stir evenly to obtain alloy melt;

[0072] (2) Refining treatment: The alloy melt obtained in step (1) is refined to complete degassing and impurity removal;

[0073] (3) Casting: The refined melt is cast into aluminum alloy ingots at a casting temperature of 700-750℃ and a casting speed of 50mm / min.

[0074] (4) Homogenization treatment: The aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment. The homogenization treatment temperature is 540-560℃ and the holding time is 10h.

[0075] (5) Cooling treatment: Cool the homogenized aluminum alloy ingot to 150-180℃ at a cooling rate of 100-120℃ / hour, and then cool it to room temperature with water mist.

[0076] (6) Forming: The cooled aluminum alloy ingot is fed into an extrusion press for extrusion forming. The extrusion temperature is 475-485℃, the extrusion rate is 12m / min, and the extrusion pressure is 150MPa.

[0077] (7) Quenching and cooling: Quench and cool the extruded material to room temperature. The quenching temperature is 455-465℃, and the temperature is held for 4 hours. Then, cool it to room temperature with water.

[0078] (8) Artificial aging: The quenched and cooled profiles are artificially aged at a temperature of 190-200℃ for 7 hours, and then cooled to room temperature.

[0079] (9) Surface anti-corrosion treatment: Spray the surface treatment agent onto the profile surface, cure at 170℃ for 30 minutes after spraying, and then let it cool naturally.

[0080] Step (1) The melting temperature is 740-750℃ and the melting time is 7h.

[0081] The refining method in step (2) is as follows: Argon gas is used to blow refining agent into the molten aluminum to carry out in-furnace refining. The amount of refining agent is 2.5% of the weight of the alloy melt, and the in-furnace refining time is 20 minutes.

[0082] Step (9) The surface treatment agent is a silica sol solution with corrosion inhibitor. The specific preparation method is as follows: 0.1 mmol of 2,5-furandicarboxylic acid and 0.1 mmol of cerium nitrate are added sequentially to 5 ml of mixed solvent. The mixed solvent consists of N,N-dimethylacetamide, ethanol and deionized water in a volume ratio of 1:1:1. After ultrasonic treatment of the mixed solution for 15 min, it is transferred to a reaction vessel and reacted at 95℃ for 48 h. After cooling to room temperature and drying, the corrosion inhibitor is obtained. Take nano silica sol, add 1-3% of the corrosion inhibitor by mass of nano silica sol under ultrasonication, disperse it evenly, adjust the pH of the system to 4.5-5.5, and then add 15% of methyltrimethoxysilane by mass of nano silica sol. Mix and react at room temperature for 8 h to obtain the surface treatment agent.

[0083] The nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 50%.

[0084] The surface treatment agent is sprayed to a thickness of 1-3 μm.

[0085] Comparative Example 1

[0086] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0087] The rare earth metal element is La.

[0088] Compared with Example 1, this comparative example uses only La as the rare earth metal element, while the other raw materials and preparation processes are the same as in Example 1.

[0089] Comparative Example 2

[0090] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0091] The rare earth metal element is Pr.

[0092] Compared with Example 1, this comparative example uses only Pr as the rare earth metal element, while the other raw materials and preparation processes are the same as in Example 1.

[0093] Comparative Example 3

[0094] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0095] The rare earth metal element is Gd.

[0096] Compared with Example 1, this comparative example uses only Gd as the rare earth metal element, while the other raw materials and preparation processes are the same as in Example 1.

[0097] Comparative Example 4

[0098] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, composite rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0099] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 2:1:1.

[0100] Compared with Example 1, this comparative example is identical to Example 1 except for the mass ratio of rare earth metal elements. All other raw materials and preparation processes are the same.

[0101] Comparative Example 5

[0102] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, composite rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0103] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:2:1.

[0104] Compared with Example 1, this comparative example is identical to Example 1 except for the mass ratio of rare earth metal elements. All other raw materials and preparation processes are the same.

[0105] Comparative Example 6

[0106] An aluminum alloy profile for new energy vehicles comprises the following components by mass percentage: Fe 0.14%, Si 0.58%, Mg 0.6%, Cu 0.25%, Mn 0.07%, Cr 0.14%, Zn 0.01%, Ti 0.03%, composite rare earth metal elements 0.6%, and the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%.

[0107] The composite rare earth metal elements are La, Pr and Gd, with a mass ratio of 1:1:2.

[0108] Compared with Example 1, this comparative example is identical to Example 1 except for the mass ratio of rare earth metal elements. All other raw materials and preparation processes are the same.

[0109] Comparative Example 7

[0110] Compared with Example 1, this comparative example differs only in the composition of the surface treatment agent, i.e., only the modified silica sol is used; all other raw materials and preparation processes are the same as in Example 1.

[0111] Step (9) The surface treatment agent is a silica sol solution. The specific preparation method is as follows: take nano silica sol, adjust the pH of the system to 4.5-5.5, add 10% of the mass of nano silica sol with methyltrimethoxysilane, mix and react at room temperature for 8 hours to obtain the surface treatment agent.

[0112] The nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 20%.

[0113] Performance testing

[0114] Test samples: Aluminum profiles were prepared according to the methods of Examples 1-3 and Comparative Examples 1-7;

[0115] Mechanical property testing: The mechanical properties of the aluminum profile samples provided in the examples and comparative examples were tested in accordance with the testing standard GB / T228.1-2021.

[0116] Electrochemical testing: The sample was tested using a CHI600E electrochemical workstation manufactured by Shanghai Chenhua Co., Ltd. A standard three-electrode system was used in the experiment, with the test sample as the working electrode, a calomel electrode as the reference electrode, and a platinum sheet electrode as the auxiliary electrode. A 3.5% (w / w) NaCl aqueous solution was prepared as the corrosive medium (a 3.5% (w / w) NaCl aqueous solution was used as a model), and the working electrode area was 3.14 cm². 2The voltage test range is -2 to 0V, and the potential scan rate is 3mV / s.

[0117] All test results were repeated 5 times, and the average of the results was taken.

[0118] Table 1 Performance Test Results

[0119]

[0120] As shown in Table 1, the mechanical properties of the profiles in the embodiments of this invention meet the requirements of over 320 MPa, yield strength over 340 MPa, and elongation after fracture exceeding 10%, thus satisfying the mechanical property requirements of various components in new energy vehicles. Simultaneously, this invention exhibits a high corrosion potential and a low corrosion current density. A higher corrosion potential indicates a lower tendency to corrosion; while current density reflects the corrosion rate—a lower current density indicates a slower corrosion rate, demonstrating excellent corrosion resistance. In contrast, comparative examples 1-6 with altered elemental compositions and comparative example 7 with altered surface treatment agent compositions showed a certain degree of weakening in both mechanical properties and corrosion resistance. This is because altering the rare earth element composition in comparative examples 1-6 disrupted the synergistic balance between La, Pr, and Gd with different atomic radii and transformation capabilities, weakening grain refinement and metamorphic effects, thus leading to a decrease in overall mechanical properties and corrosion resistance.

[0121] Typical samples were selected, and the grain morphology of the samples obtained in Example 1 and Comparative Examples 1-7 was observed under polarized light mode using a ZEISSS microscope. Figure 1 As shown, the sample in Example 1 of this invention has fine and uniform grains, while the comparative example has relatively large grains. Comparative Example 7 only involves the surface treatment part, and the grain morphology is basically similar to that of Example 1.

[0122] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. An aluminum alloy profile for new energy vehicles, characterized in that, The aluminum alloy profile comprises, by mass percentage, the following components: Fe 0.14-0.19%, Si 0.58-0.66%, Mg 0.6-1.3%, Cu 0.25-0.35%, Mn 0.07-0.15%, Cr 0.14-0.22%, Zn 0.01-0.05%, Ti 0.03-0.15%, and composite rare earth metal elements 0.6-0.9%, with the balance being Al and impurities, wherein the total impurity content is not greater than 0.25%; the composite rare earth metal elements are La, Pr, and Gd, with a mass ratio of 1:1:1; the preparation method of the aluminum alloy profile includes the following preparation steps: (1) Smelting: Prepare raw materials of various metal elements in proportion, melt aluminum ingots, add other metal elements, heat and melt, stir evenly to obtain alloy melt; (2) Refining treatment: The alloy melt obtained in step (1) is refined to complete degassing and impurity removal; (3) Casting: The refined melt is cast into aluminum alloy ingots at a casting temperature of 700-750℃ and a casting speed of 30-50mm / min. (4) Homogenization treatment: The aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment. The homogenization treatment temperature is 540-560℃ and the holding time is 5-10h. (5) Cooling treatment: Cool the homogenized aluminum alloy ingot to 150-180℃ at a cooling rate of 100-120℃ / hour, and then cool it to room temperature with water mist. (6) Forming: The cooled aluminum alloy ingot is fed into an extrusion press for extrusion forming. The extrusion temperature is 475-485℃, the extrusion rate is 10-12m / min, and the extrusion pressure is 120-150MPa. (7) Quenching and cooling: Quench and cool the extruded material to room temperature. The quenching temperature is 455-465℃, and the temperature is held for 3-4 hours. Then, cool it to room temperature with water. (8) Artificial aging: The quenched and cooled profiles are artificially aged at a temperature of 190-200℃ for 5-7 hours, and then cooled to room temperature. (9) Surface anti-corrosion treatment: Spray the surface treatment agent onto the profile surface, cure at 170℃ for 30 minutes after spraying, and then let it cool naturally. Step (9) The surface treatment agent is a silica sol solution with corrosion inhibitor. The specific preparation method is as follows: 0.1 mmol of 2,5-furandicarboxylic acid and 0.1 mmol of cerium nitrate are added sequentially to 5 ml of mixed solvent. The mixed solvent consists of N,N-dimethylacetamide, ethanol and deionized water in a volume ratio of 1:1:

1. After ultrasonic treatment of the mixed solution for 15 min, it is transferred to a reaction vessel and reacted at 95℃ for 48 h. After cooling to room temperature and drying, the corrosion inhibitor is obtained. Take nano silica sol, add 1-3% of the corrosion inhibitor by mass of nano silica sol under ultrasonication, and after fully dispersing and uniformly dispersing, adjust the pH of the system to 4.5-5.5, and then add 10-15% of methyltrimethoxysilane by mass of nano silica sol. Mix and react at room temperature for 8 h to obtain the surface treatment agent.

2. The aluminum alloy profile for new energy vehicles according to claim 1, characterized in that, Step (1) The melting temperature is 740-750℃ and the melting time is 5-7h.

3. The aluminum alloy profile for new energy vehicles according to claim 1, characterized in that, The refining method in step (2) is as follows: Argon gas is used to blow refining agent into the molten aluminum formed by melting for in-furnace refining. The amount of refining agent is 1.5-2.5% of the weight of the alloy melt, and the in-furnace refining time is 17-20 minutes.

4. The aluminum alloy profile for new energy vehicles according to claim 1, characterized in that, The nano-silica sol has an average particle size of 30-50 nm and a mass concentration of 20-50%.

5. The aluminum alloy profile for new energy vehicles according to claim 1, characterized in that, The surface treatment agent is sprayed to a thickness of 1-3 μm.

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