High-strength and high-toughness aluminum alloy for vehicle and preparation method thereof

Abstract

The invention discloses a high-strength and high-toughness aluminum alloy for a vehicle and a preparation method of the aluminum alloy, and relates to the technical field of aluminum alloy manufacturing for the vehicle, and the aluminum alloy comprises the following components: the aluminum alloy comprises the following components: 3.5-6.5 wt% of Si; the content of Zn is less than or equal to 0.2 wt%; the content of Mn is 0.2 to 0.3 wt%; the content of Mg is less than or equal to 0.4 wt%; the content of Zr is less than or equal to 0.2 wt%; the content of Cr is less than or equal to 0.15 wt%; the content of Y is 0.002 to 0.01 weight percent; the content of Ti is 0.01 to 0.04 weight percent; the content of La and Sc mixed rare earth is 0.001 to 0.01 weight percent; and the balance of Al. The aluminum alloy has high strength and good plasticity, ductility and flow formability, heat treatment is not needed, good mechanical performance can be obtained only through simple casting treatment, the machining technology is simplified, and the difficulty and cost of die-casting aluminum alloy are reduced.

Description

Technical Field

[0001] This invention relates to the field of high-strength aluminum alloy manufacturing technology, specifically to a high-strength and high-toughness aluminum alloy for automobiles and its preparation method. Background Technology

[0002] Reducing vehicle weight, lowering energy consumption, minimizing environmental pollution, improving fuel economy, and conserving limited resources have become key focuses for major automakers. Aluminum possesses advantages such as low density, light weight, good formability, recyclability, energy efficiency, and environmental friendliness. Combined with its ability to extend vehicle lifespan, it plays a significant role in vehicle lightweighting, improving driving performance and safety, reducing fuel consumption, emissions, and environmental pollution. However, existing aluminum alloy materials still suffer from low strength and inadequate mechanical properties. Therefore, there is an urgent need to improve the mechanical properties of existing aluminum alloy materials.

[0003] Traditional 6063 and 6061 have some applications in the automotive lightweighting process due to their good extrudability. However, their strength and toughness cannot meet the requirements for load-bearing structural components such as body panels. While 6082 has higher strength, its extrusion formability is poor and the dimensional accuracy of the processed profile cannot be guaranteed, so it cannot be used to prepare complex multi-cavity structural profiles.

[0004] Therefore, there is a need for a high-strength and high-toughness aluminum alloy for vehicle bodies and its preparation method, which, while possessing high strength and high toughness, also exhibits good plasticity and extrusion properties, and can ensure the dimensional accuracy of the profile parts after processing and forming. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a high-strength and high-toughness aluminum alloy for automobiles. This aluminum alloy has high strength, good ductility, elongation and flowability, and does not require heat treatment. It can achieve good mechanical properties with only simple casting, which simplifies the processing technology and reduces the difficulty and cost of die-casting aluminum alloys.

[0006] This invention discloses a high-strength, high-toughness aluminum alloy for automotive applications, the composition of which is as follows:

[0007] The Si content is 3.5–6.5 wt%.

[0008] Zn content ≤0.2wt%,

[0009] The Mn content is 0.2–0.3 wt%.

[0010] The Mg content is ≤0.4wt%.

[0011] Zr content is ≤0.2wt%.

[0012] The Cr content is ≤0.15wt%.

[0013] The Y content is 0.002–0.01 wt%.

[0014] Ti content 0.01–0.04 wt%.

[0015] The content of the mixed rare earth elements La and Sc is 0.001–0.01 wt%.

[0016] The rest are Al.

[0017] As an improvement to the above technical solution, the composition of the aluminum alloy is as follows:

[0018] The Si content is 3.5–5.5 wt%.

[0019] The Zn content is 0.008–0.15 wt%.

[0020] The Mn content is 0.25–0.3 wt%.

[0021] The Mg content is 0.2–0.4 wt%.

[0022] The Zr content is 0.05–0.2 wt%.

[0023] The Cr content is 0.008–0.15 wt%.

[0024] The Y content is 0.005–0.01 wt%.

[0025] Ti content 0.02–0.04 wt%.

[0026] The content of the mixed rare earth elements La and Sc is 0.005–0.01 wt%.

[0027] The rest are Al.

[0028] As an improvement to the above technical solution, the content of Y is 0.007 to 0.009 wt%.

[0029] As an improvement to the above technical solution, the Ti content is 0.02–0.03 wt%.

[0030] As an improvement to the above technical solution, the content of the La and Sc mixed rare earth elements is 0.007 to 0.009 wt%.

[0031] As an improvement to the above technical solution, the aluminum alloy sheet has a tensile strength of 380MPa or higher, a yield strength of 290MPa or higher, and an elongation of 9% or higher.

[0032] Accordingly, the present invention also discloses a method for preparing a high-strength, high-toughness aluminum alloy for automobiles as described above, comprising the following steps:

[0033] (1) Batching: Weigh the corresponding raw materials according to the mass percentage of the components determined by the above aluminum alloy composition range;

[0034] (2) First smelting: The weighed raw material aluminum ingots are placed into the smelting furnace for smelting until the aluminum ingots are completely melted to form aluminum melt;

[0035] (3) Second melting: Si raw materials, Zn raw materials, Cu raw materials, Mn raw materials, Cr raw materials, Zr raw materials and La and Sc mixed rare earth raw materials are added in sequence according to the degree of easy oxidation and burn-off of the furnace charge. The melting temperature is 770-790℃ and the melting time is 25-35min to obtain the first alloy melt.

[0036] (4) First slag removal: Add slag remover to the first alloy melt for slag removal treatment, and turn on the electromagnetic stirring equipment to stir the first alloy melt for 10-20 minutes.

[0037] (5) Third melting: Add Mg raw material, Ti raw material and Y raw material to the first alloy melt after slag removal and carry out the third melting. The melting temperature is 710-730℃ and the melting time is 10-15min to obtain the second alloy melt.

[0038] (6) Second slag removal: Turn on the electromagnetic stirring of the second alloy melt for 5-10 minutes, let it stand for 8-10 minutes, stir again, and repeat the stirring-standing cycle at least twice. Then remove the floating slag from the surface of the aluminum melt to obtain the third alloy melt.

[0039] (7) Degassing and refining: Powdered sodium-free refining agent is sprayed into the third alloy melt, and argon is used as the refining gas for in-furnace refining. The refining time is 13-17 minutes. After refining, the slag is removed.

[0040] (8) Filtration and sampling analysis: The composition content of the third alloy melt is tested. After the test results are qualified, the aluminum melt is filtered online by a double-stage ceramic filter plate and an ultra-fine particle filter tube group. After filtration, the composition content of the third alloy melt is tested. After the test results are qualified, it is allowed to stand for 10-20 minutes and then slag removal is performed to obtain the fourth alloy melt.

[0041] (9) The fourth alloy melt from the previous step is die-cast into an ingot.

[0042] As an improvement to the above technical solution, the slag remover in step (4) is the XW-8871 type refining agent.

[0043] As an improvement to the above technical solution, the dual-stage ceramic filter plate in step (8) adopts a set of schemes with a mesh size of 30+40ppi, 30+50ppi, 40+50ppi, 40+60ppi, and 50+60ppi, and the ultrafine particle filter tube group in step (8) is selected as a 22-26 tube group with a maximum inclusion particle size of no more than 5μm.

[0044] As an improvement to the above technical solution, the die-casting processing parameters in step (9) are: die-casting temperature 635-655℃, vacuum pressure <100mbr, die-casting pressure 65-75MPa, and die-casting speed 2-3m / s.

[0045] The beneficial effects of this invention are as follows: by controlling the types and content ranges of alloying elements and improving the manufacturing process, the chemical composition, structure and properties of the obtained aluminum alloy can be made uniform, eliminating the problem of dendrite segregation in aluminum alloy, ensuring that the mechanical properties of each part are uniform and consistent, so as to obtain ultra-high tensile strength and yield strength, wherein the yield strength is greater than 300MPa and the tensile strength is greater than 330MPa.

[0046] The automotive body, rear body, front compartment and other thin-walled structural parts made of the above-mentioned ultra-high strength aluminum alloy plate have superior mechanical properties compared with existing materials, and the aluminum alloy die castings of the present invention can be obtained without heat treatment, which can effectively simplify the processing technology and reduce the difficulty and cost of die casting aluminum alloys. Detailed Implementation

[0047] The specific embodiments of the present invention will be further described below with reference to the examples. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0048] This application discloses a high-strength and high-toughness aluminum alloy for automobiles and its preparation method. The aim is to provide an aluminum alloy sheet with high strength and good ductility, elongation and flowability, so that it can be used in thin-walled structural parts of automobiles such as car bodies, rear bodies and front compartments. Moreover, it can achieve good mechanical properties with only simple casting, which simplifies the processing technology and reduces the difficulty and cost of die-casting aluminum alloys.

[0049] The inventive concept of the high-strength and high-toughness aluminum alloy in this application is to obtain excellent tensile strength and yield strength by selecting matching alloying elements and controlling their contents, and by optimizing and improving the process to make the alloying elements bond more tightly.

[0050] According to an embodiment of this application, the high-strength, high-toughness aluminum alloy for automobiles has the following composition:

[0051] The Si content is 3.5–6.5 wt%.

[0052] Zn content ≤0.2wt%,

[0053] The Mn content is 0.2–0.3 wt%.

[0054] The Mg content is ≤0.4wt%.

[0055] Zr content is ≤0.2wt%.

[0056] The Cr content is ≤0.15wt%.

[0057] The Y content is 0.002–0.01 wt%.

[0058] Ti content 0.01–0.04 wt%.

[0059] The content of the mixed rare earth elements La and Sc is 0.001–0.01 wt%.

[0060] The rest are Al.

[0061] The added Zn can promote the precipitation of precipitated phases, thereby improving the mechanical and processing properties of aluminum alloys. By setting the amount of Zn added to no more than 0.2%, not only can excessive Zn be avoided from increasing the hot brittleness and reducing the corrosion resistance of aluminum alloys, but the precipitation effect of Zn on precipitated phases can also be guaranteed.

[0062] The added Mn can react with Al to form MnAl6. MnAl6 not only refines the recrystallized grains to improve the elongation of the aluminum alloy, but also improves the mold release properties and mechanical strength of the aluminum alloy. This application controls the amount of Mn added to be 0.2-0.3%. At this content, Mn can effectively improve the mold release properties and increase the elongation and mechanical strength of the aluminum alloy.

[0063] The added Mg has an elemental composition that enhances strength through solid solution strengthening and precipitation strengthening. In the aluminum alloy of this application, by setting the amount of Zn added to no more than 0.4%, the crystals can be made finer, thus providing strength to the alloy.

[0064] With the above-mentioned basic elements combined, the addition of appropriate amounts of Y, Ti, La, and Sc elements results in aluminum alloys with both high strength and good toughness. This also eliminates the need for heat treatment during the subsequent preparation of die-cast aluminum alloy parts. Specifically, Ti refines the microstructure in the alloy melt, improving alloy toughness and increasing the alloy's elastic modulus. Strontium acts as a modifier in the alloy melt, reducing ingot homogenization time and the tendency for the alloy to stick to the die during die casting, providing consistent mechanical properties and toughness. Y element acts as a grain refiner and also precipitates fine AlV phases in the aluminum matrix, resulting in precipitation strengthening. Both elements work together to improve the strength and toughness of the aluminum alloy. The added La and Sc rare earth elements refine the microstructure in the alloy melt. However, the addition of rare earth elements typically requires alloys with high magnesium content to effectively activate this refining effect. While ensuring the stability of the aluminum alloy's own toughness, it effectively reduces the presence of lamellar iron-rich phases, allowing the aluminum alloy to tolerate higher Fe impurity content.

[0065] By controlling the composition and content range of the aluminum alloy plate of this application, the aluminum alloy manufactured using the improved preparation method described below can have high strength and high toughness.

[0066] The relevant embodiments and comparative examples are described below:

[0067] Example 1:

[0068] A high-strength and high-toughness aluminum alloy for automotive applications, the contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La and Sc in the aluminum alloy are shown in Table 1.

[0069] The preparation method of this high-strength and high-toughness aluminum alloy for automobiles includes the following steps:

[0070] (1) Batching: Weigh the corresponding raw materials according to the mass percentage of the components determined by the above aluminum alloy composition range;

[0071] (2) First smelting: The weighed raw material aluminum ingots are placed into the smelting furnace for smelting until the aluminum ingots are completely melted to form aluminum melt;

[0072] (3) Second melting: Si raw materials, Zn raw materials, Cu raw materials, Mn raw materials, Cr raw materials, Zr raw materials and La and Sc mixed rare earth raw materials are added in sequence according to the degree of easy oxidation and burn-off of the furnace charge for the second melting. The melting temperature is 780℃ and the melting time is 30min to obtain the first alloy melt.

[0073] (4) First slag removal: Add slag remover to the first alloy melt for slag removal treatment, and turn on the electromagnetic stirring device to stir the first alloy melt for 15 minutes;

[0074] (5) Third melting: Add Mg raw material, Ti raw material and Y raw material to the first alloy melt after slag removal and carry out the third melting. The melting temperature is 720℃ and the melting time is 13min to obtain the second alloy melt.

[0075] (6) Second slag removal: After turning on the electromagnetic stirring for 8 minutes and letting it stand for 9 minutes, stir again. Repeat the stirring-standing process twice. Then remove the slag from the surface of the aluminum melt to obtain the third alloy melt.

[0076] (7) Degassing and refining: Powdered sodium-free refining agent is sprayed into the third alloy melt, and argon is used as the refining gas for in-furnace refining. The refining time is 15 minutes, and the slag is removed after refining.

[0077] (8) Filtration and sampling analysis: The composition content of the third alloy melt is tested. After the test results are qualified, the aluminum melt is filtered online by a double-stage ceramic filter plate and an ultra-fine particle filter tube group. After filtration, the composition content of the third alloy melt is tested. After the test results are qualified, it is allowed to stand for 15 minutes and then slag removal is performed to obtain the fourth alloy melt.

[0078] (9) The fourth alloy melt from the previous step is poured into the hot top casting crystallizer for continuous casting of ingots. During the casting process, an ultrasonic vibration system is used to ultrasonically treat the aluminum ingots along the circumference of the casting port to obtain aluminum alloy round ingot products.

[0079] Example 2:

[0080] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0081] Example 3:

[0082] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0083] Example 4:

[0084] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0085] Example 5:

[0086] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0087] Example 6:

[0088] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0089] Example 7:

[0090] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0091] Example 8:

[0092] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0093] Example 9:

[0094] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the automotive aluminum alloy of this embodiment are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy of this embodiment is the same as in Example 1.

[0095] Comparative Example 1:

[0096] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0097] Comparative Example 2:

[0098] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0099] Comparative Example 3:

[0100] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0101] Comparative Example 4:

[0102] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0103] Comparative Example 5:

[0104] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0105] Comparative Example 6:

[0106] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0107] Comparative Example 7:

[0108] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0109] Comparative Example 8:

[0110] The contents of Si, Zn, Mn, Mg, Cr, Zr, Y, Ti, La, and Sc in the comparative example automotive aluminum alloy are shown in Table 1, and other conditions are the same as in Example 1. The preparation method of the automotive aluminum alloy in this example is the same as in Example 1.

[0111] Table 1. Chemical composition of automotive aluminum alloys in Examples 1-9 and Comparative Examples 1-8

[0112]

[0113]

[0114]

[0115] Performance testing:

[0116] The tensile strength of the automotive aluminum alloys prepared in Examples 1-9 and Comparative Examples 1-8 was tested according to GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0117] The yield strength of the automotive aluminum alloys prepared in Examples 1-9 and Comparative Examples 1-8 was tested according to GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0118] The elongation of the automotive aluminum alloys prepared in Examples 1-9 and Comparative Examples 1-8 was tested according to GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0119] Three samples were tested under the same conditions, and the average value was taken. The test results are shown in Table 2.

[0120] Table 2. Performance test results

[0121]

[0122]

[0123] As shown in Table 2, the alloy compositions and preparation processes of Examples 1-9 conforming to the present invention exhibit relatively higher tensile strength and yield strength compared to Comparative Examples 1-8. Furthermore, the alloys prepared in Examples 1-9 all meet the requirements of a yield strength greater than 290 MPa and a tensile strength greater than 380 MPa, demonstrating ultra-high strength. In contrast, Comparative Examples 1-8, which do not meet the alloy compositions and contents of the present invention, show lower yield strength, tensile strength, and elongation compared to the examples.

[0124] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength, high-toughness aluminum alloy for automotive applications, characterized in that, The composition of the aluminum alloy is as follows: The Si content is 3.5–6.5 wt%. The Zn content is ≤0.2wt%. The Mn content is 0.2–0.3 wt%. The Mg content is ≤0.4wt%. Zr content is ≤0.2wt%. The Cr content is ≤0.15wt%. The Y content is 0.002–0.01 wt%. Ti content 0.01–0.04 wt%. The content of the mixed rare earth elements La and Sc is 0.001–0.01 wt%. The rest are Al.

2. The high-strength, high-toughness aluminum alloy sheet for automotive applications as described in claim 1, characterized in that, The composition of the aluminum alloy is as follows: The Si content is 3.5–5.5 wt%. The Zn content is 0.008–0.15 wt%. The Mn content is 0.25–0.3 wt%. The Mg content is 0.2–0.4 wt%. The Zr content is 0.05–0.2 wt%. The Cr content is 0.008–0.15 wt%. The Y content is 0.005–0.01 wt%. Ti content 0.02–0.04 wt%. The content of the mixed rare earth elements La and Sc is 0.005–0.01 wt%. The rest are Al.

3. The high-strength, high-toughness aluminum alloy for automotive applications as described in claim 2, characterized in that, The content of Y is 0.007–0.009 wt%.

4. The high-strength, high-toughness aluminum alloy for automotive applications as described in claim 2, characterized in that, The Ti content is 0.02–0.03 wt%.

5. A high-strength, high-toughness aluminum alloy for automotive applications as described in claim 2, characterized in that, The content of the mixed rare earth elements La and Sc is 0.007–0.009 wt%.

6. A high-strength, high-toughness aluminum alloy for automotive applications according to any one of claims 1-5, characterized in that, The aluminum alloy sheet has a tensile strength of 380 MPa or higher, a yield strength of 290 MPa or higher, and an elongation of 9% or higher.

7. A method for preparing a high-strength, high-toughness aluminum alloy for automobiles as described in any one of claims 1-6, characterized in that, The following steps are involved: (1) Batching: Weigh the corresponding raw materials according to the mass percentage of the components determined by the above aluminum alloy composition range; (2) First smelting: The weighed raw material aluminum ingots are placed into the smelting furnace for smelting until the aluminum ingots are completely melted to form aluminum melt; (3) Second melting: Si raw materials, Zn raw materials, Cu raw materials, Mn raw materials, Cr raw materials, Zr raw materials and La and Sc mixed rare earth raw materials are added in sequence according to the degree of easy oxidation and burn-off of the furnace charge. The melting temperature is 770-790℃ and the melting time is 25-35min to obtain the first alloy melt. (4) First slag removal: Add slag remover to the first alloy melt for slag removal treatment, and turn on the electromagnetic stirring equipment to stir the first alloy melt for 10-20 minutes. (5) Third melting: Add Mg raw material, Ti raw material and Y raw material to the first alloy melt after slag removal and carry out the third melting. The melting temperature is 710-730℃ and the melting time is 10-15min to obtain the second alloy melt. (6) Second slag removal: Turn on the electromagnetic stirring of the second alloy melt for 5-10 minutes, let it stand for 8-10 minutes, stir again, and repeat the stirring-standing cycle at least twice. Then remove the floating slag from the surface of the aluminum melt to obtain the third alloy melt. (7) Degassing and refining: Powdered sodium-free refining agent is sprayed into the third alloy melt, and argon is used as the refining gas for in-furnace refining. The refining time is 13-17 minutes. After refining, the slag is removed. (8) Filtration and sampling analysis: The composition content of the third alloy melt is tested. After the test results are qualified, the aluminum melt is filtered online by a double-stage ceramic filter plate and an ultra-fine particle filter tube group. After filtration, the composition content of the third alloy melt is tested. After the test results are qualified, it is allowed to stand for 10-20 minutes and then slag removal is performed to obtain the fourth alloy melt. (9) The fourth alloy melt from the previous step is die-cast into an ingot.

8. The method for preparing high-strength and high-toughness aluminum alloy for automobiles according to claim 7, characterized in that, The slag remover in step (4) is the XW-8871 type refining agent.

9. The method for preparing high-strength and high-toughness aluminum alloy for automobiles according to claim 7, characterized in that, The dual-stage ceramic filter plate in step (8) adopts one of the following schemes with a mesh size of 30+40ppi, 30+50ppi, 40+50ppi, 40+60ppi, and 50+60ppi. The ultrafine particle filter tube group in step (8) is selected as a 22-26 tube group with a maximum inclusion particle size of no more than 5μm.

10. The method for preparing high-strength and high-toughness aluminum alloy for automobiles according to claim 7, characterized in that, The die-casting parameters in step (9) are: die-casting temperature 635-655℃, vacuum pressure <100mbr, die-casting pressure 65-75MPa, and die-casting speed 2-3m / s.

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