High-impact-resistance aluminum alloy and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloy materials, in particular to a high-impact-resistance aluminum alloy and a preparation method thereof.The high-impact-resistance aluminum alloy comprises, by mass, 0.03%-0.15% of silicon, 0.03%-0.15% of aluminum, 0.05%-0.15% of silicon, 0.05%-0.15% of silicon, 0.05%-0.15% of silicon, 0.05%-0.15% of silicon, 0.05 4.2%-4.4% of copper; 0.01 to 0.05 percent of chromium; 0.8 to 1.0 percent of magnesium; 0.05 to 0.08% of zinc; 0.7%-0.9% of manganese; 0.15%-0.25% of niobium; 0.01 to 0.05 percent of strontium; 0.08% to 0.12% of zirconium; 0.01 to 0.05 percent of titanium; 0.2 to 0.25 percent of rare earth elements; less than 0.12% of impurity iron; other impurity elements are less than 0.1%; and the balance of aluminum. The rare earth elements comprise cerium, scandium, yttrium and erbium. The prepared aluminum alloy has high strength and high impact resistance at the same time.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials technology, specifically to a high impact-resistant aluminum alloy and its preparation method. Background Technology

[0002] Aluminum alloys have become the core structural material for automobiles, aerospace, high-speed rail and other transportation vehicles due to their low density and high specific strength. However, modern industry has put forward strict requirements for their impact resistance. For example, when aluminum alloys are used in high-load parts such as robot joints, their toughness is relatively poor and they are prone to brittle fracture under complex stress. In order to improve the impact resistance of aluminum alloys, the industry has formed three mainstream technical paths, but all of them have obvious shortcomings: (1) Fiber metal laminate technology, the principle of which is to alternately lay aluminum alloy thin plates with carbon fiber, glass fiber and other reinforcing composite materials, and pressurize and cure to form a laminate structure, combining the plasticity of metal and the high strength of fiber. It is characterized by high fatigue tolerance and impact resistance, and has been applied to parts such as aircraft fuselage skin, but the interlayer bonding force is easily affected by the process, and the preparation cost is high and the molding process is complicated. (2) Foam alloy reinforcement technology, the principle of which is to introduce a porous foam structure into aluminum alloy, and use the energy absorption characteristics of the pores to buffer the impact energy. It is often used as a filling material for automotive collision energy absorption components. The characteristic is that the buffering and energy absorption effect is significant, but the yield strength of aluminum foam itself is low, and it needs to be used with high-strength panels. It cannot withstand high impact energy when used alone. (3) Alloy composition optimization and heat treatment. The principle is to adjust the alloy composition by adding Mg, Si, Cu, rare earth elements, etc., or to refine the grains and regulate the distribution of strengthening phases by using T6 heat treatment to improve impact toughness. The characteristic is that it can improve the performance to a certain extent, but conventional cast aluminum alloys are difficult to balance strength, elongation and impact toughness at the same time. For example, Al-Cu-Mg alloys are prone to toughness reduction due to brittle phase precipitation.

[0003] Patent CN114369745B discloses a high-strength aluminum alloy, its preparation method, and its applications. The high-strength aluminum alloy of this invention comprises the following components by mass percentage: Cu: 0.32~0.53%, Iron: 0.12~0.25%, Mn: 0.55~0.9%, Si: 0.9~1.36%, Mg: 0.53~0.85%, Cr: 0.15~0.22%, Y: 0.10~0.15%, Ti: 0.01~0.04%, total impurities ≤0.15%, and the balance being Al. The high-strength aluminum alloy prepared using this invention exhibits good mechanical properties and crush resistance, effectively meeting users' demands for lightweight materials. However, the iron content of 0.12-0.25% easily forms a hard and brittle acicular β-iron phase, resulting in a weakness in the aluminum alloy's toughness.

[0004] Patent CN115555572B discloses a method for preparing an Al-Zn-Mg-Cu-Zr-Sn-RE alloy that meets the requirements of powder metallurgy and has good sintering characteristics. It uses pure Al powder as the main raw material, with other alloying elements introduced as elemental powders or simple intermediate alloy powders. After the raw material powders are mixed uniformly in a certain proportion, they undergo pressing, sintering, and heat treatment to obtain aluminum alloy parts. This invention utilizes the alteration of rare earth elements to transform them into dispersed nano-rare earth oxide particles, improving grain boundary strength. Furthermore, by controlling particle size distribution, pressing pressure, and sintering process parameters, the microstructure is regulated to improve the mechanical properties of the aluminum alloy. However, while adding 0.1-1.0% tin can promote sintering by forming a low-melting-point eutectic phase, excessive liquid tin phase enrichment at grain boundaries can severely impair the alloy's toughness.

[0005] Therefore, there is an urgent need in the market to develop an aluminum alloy material that combines high strength and high impact resistance. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to obtain an aluminum alloy material that has both high strength and high impact resistance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a high-impact-resistant aluminum alloy, comprising the following components by weight percentage (100%): silicon 0.03-0.15%; copper 4.2-4.4%; chromium 0.01-0.05%; magnesium 0.8-1.0%; zinc 0.05-0.08%; manganese 0.7-0.9%; niobium 0.15-0.25%; strontium 0.01-0.05%; zirconium 0.08-0.12%; titanium 0.01-0.05%; rare earth elements 0.2-0.25%; iron impurities <0.12%; other impurity elements <0.1%; the balance being aluminum; wherein the rare earth elements include cerium, scandium, yttrium, and erbium.

[0008] This application achieves high strength and high impact resistance in an aluminum alloy by adjusting the content of conventional elements such as silicon, copper, magnesium, zinc, and manganese, and by adding zirconium, niobium, strontium, and rare earth elements. Zirconium and niobium form L12-type coherent composite phases such as Al3(Zr,Sc) with scandium and erbium, which is beneficial for improving the thermal stability of the aluminum alloy.

[0009] This application achieves core strength by adding a high copper content to the aluminum alloy, which forms a large number of fine Al2Cu reinforcing phases. Simultaneously, by suppressing the silicon content to 0.03-0.15%, the coarse and brittle eutectic silicon phase is fundamentally avoided, ensuring the high toughness and ductility of the aluminum alloy. Furthermore, limiting the iron content to <0.12% reduces the formation of hard and brittle acicular β-iron phase, thereby improving the toughness of the aluminum alloy.

[0010] This application achieves comprehensive structural optimization at the nano and micro scales through multi-element synergy. Niobium, zirconium, and titanium form stable niobium aluminide, zirconium aluminide, and titanium aluminide nanoparticles, which strongly pinnate grain boundaries and dislocations in the aluminum alloy, achieving deep grain refinement and inhibiting recrystallization, further enhancing the toughness of the aluminum alloy. Light rare earth elements such as cerium purify the melt and modify inclusions, while scandium, yttrium, and erbium provide significant grain refinement, inhibit recrystallization, and direct strengthening effects. This application also adds trace amounts of strontium to modify any trace silicon phase that may be present, ensuring grain refinement.

[0011] In some embodiments, the mass ratio of cerium, scandium, yttrium, and erbium is 1:(0.55-0.65):(0.25-0.35):(0.25-0.35).

[0012] This application reduces the formation of coarse phases such as scandium aluminide, erbium aluminide, or aluminum-erbium-copper by limiting the ratio of cerium, scandium, yttrium, and erbium, thus ensuring the toughness of the aluminum alloy. Furthermore, the presence of scandium and yttrium may suppress the formation of harmful erbium phases by preferentially forming more stable aluminum compound phases, ensuring that erbium stably exerts its beneficial grain-refining effect.

[0013] Another aspect of the present invention provides a method for preparing a high-impact-resistant aluminum alloy, comprising the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 740-750℃ to obtain aluminum alloy melt. S2. Add refining agent to the aluminum alloy melt obtained in step S1, adjust the temperature to 730-740℃, degas with inert gas for 20-30 minutes, remove slag, cool to 715-725℃, and under argon protection, mix the preheated aluminum-strontium master alloy, aluminum-cerium master alloy, aluminum-scandium master alloy, aluminum-yttrium master alloy, and aluminum-erbium master alloy and press them into the aluminum alloy melt in one go using a bell jar. Stir for 3-5 minutes, let stand for 10-15 minutes to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The melt obtained in step S3 is subjected to semi-continuous casting to obtain ingot A; S5. Homogenize the ingot A obtained in step S4 and quench it in hot water to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment to obtain a high impact-resistant aluminum alloy.

[0014] This application describes a process involving first melting aluminum ingots and a refractory master alloy, followed by thorough refining and degassing, then adding a rare earth master alloy, and finally undergoing semi-continuous casting, solution treatment, aging, and quenching to obtain an aluminum alloy. By using a method of refining the aluminum alloy melt with a refining agent before adding rare earth elements, the amount of new oxide inclusions generated by the added refining agent can be effectively reduced, as can the loss of rare earth elements. This results in a more superior impact resistance and significantly improved toughness of the aluminum alloy material.

[0015] In some embodiments, the mass ratio of the aluminum alloy melt to the refining agent in step S2 is 1:(0.002-0.0028).

[0016] In some embodiments, the refining agent is a composition of a sodium-free refining agent and a mixture of rare earth chlorides, wherein the mass ratio of the two is 1:(0.2-0.5).

[0017] In some embodiments, the mixed rare earth chloride is lanthanum chloride or cerium chloride.

[0018] During the aluminum alloy smelting process, aluminum oxides and copper oxides easily form complex inclusions that are difficult to remove. Therefore, refining agents are needed to efficiently remove hydrogen and inclusions from the aluminum alloy. Commonly used refining agents in the prior art include sodium chloride, potassium chloride, sodium fluoride, and cryolite. The sodium element in these refining agents can severely affect the rare earth modification effect; even trace amounts of sodium can lead to rare earth failure and exacerbate the hot cracking tendency of the alloy, reducing the toughness of the aluminum alloy. To address these problems, this application uses a preferred composition of a sodium-free refining agent and mixed rare earth chlorides as the refining agent. This not only avoids the introduction of sodium ions but also further improves the impact resistance of the aluminum alloy. This is likely because: firstly, the rare earth elements (RE) in rare earth chlorides can react with hydrogen to generate REH2 solid compounds, which precipitate as slag, reducing the hydrogen content of the melt; secondly, RE can reduce the surface tension of the molten aluminum, decreasing the critical size of bubbles and accelerating their rising speed, thus stably reducing the hydrogen content and consequently reducing the pinhole rate, further improving the toughness of the aluminum alloy. Furthermore, RE undergoes substitution with oxides such as Al2O3, MgO, and SiO2, generating dense rare earth oxides that settle at the bottom, making slag removal easier. It can also synergize with sodium-free refining agents to form low-melting-point pentaceous eutectic fluxes, further enhancing the adsorption capacity of the refining agents, ensuring clean separation of slag and aluminum, and completely breaking down the oxide film in the melt, thereby improving the impact resistance of aluminum alloys.

[0019] In some embodiments, the preheating temperature in step S2 is 250-350°C, and the time is 2-4 hours.

[0020] In some embodiments, the casting speed in step S3 is 50-70 mm / min, the cooling water flow rate is 35-45 L / min, and the casting temperature is 710-720℃.

[0021] In some embodiments, the homogenization process in step S5 includes, in sequence, a primary homogenization process, a secondary homogenization process, and a heat preservation process; the temperature of the primary homogenization process is 460-470℃, and the heat preservation time is 4-6h; the temperature of the secondary homogenization process is 490-500℃, and the heat preservation time is 2-4h; the temperature of the heat preservation process is 520-530℃, and the heat preservation time is 3-5h.

[0022] In some embodiments, the aging heat treatment in step S6 is performed at a temperature of 170-190°C for 5-7 hours.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adjusts the content of conventional elements such as silicon, copper, magnesium, zinc and manganese, and adds zirconium, niobium and strontium elements and rare earth elements to make the aluminum alloy have high strength and high impact resistance.

[0024] (2) By using the method of first adding a refining agent to refine the aluminum alloy melt and then adding rare earth elements, the present invention can effectively reduce the large amount of new oxide inclusions generated by the added refining agent, reduce the loss of rare earth elements, make the aluminum alloy have better impact resistance, and significantly improve the toughness of the aluminum alloy material.

[0025] (3) The present invention uses a combination of sodium-free refining agent and mixed rare earth chloride as the refining agent, which reduces the loss rate of rare earth elements. At the same time, the addition of mixed rare earth chloride can not only improve the degassing effect of the refining agent and reduce the pinhole rate of aluminum alloy, but also form a low melting point pentagonal eutectic flux in synergy with sodium-free refining agent, further enhancing the adsorption capacity of refining agent, making the slag-aluminum separation clean, the oxide film of melt completely broken, and thus improving the impact resistance of aluminum alloy. Detailed Implementation

[0026] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0027] In the following examples and comparative examples, the compounds and related reagents used were all commercially available. The sodium-free refining agent was model M11, purchased from Jinzhou Shida Flux New Material Co., Ltd.

[0028] Example 1 A high-impact aluminum alloy, by weight percentage, contains the following components: silicon 0.09%; copper 4.3%; chromium 0.03%; magnesium 0.9%; zinc 0.06%; manganese 0.8%; niobium 0.2%; strontium 0.03%; zirconium 0.1%; titanium 0.03%; rare earth elements 0.23%; impurity iron 0.10%; other impurity elements 0.05%; the balance being aluminum; the rare earth elements include cerium, scandium, yttrium, and erbium, with a mass ratio of 1:0.6:0.3:0.3.

[0029] The preparation method of the high impact-resistant aluminum alloy in this embodiment includes the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 745℃ to obtain an aluminum alloy melt. S2. Add refining agent to the aluminum alloy melt obtained in step S1, adjust the temperature to 735℃, degas with argon for 25 minutes, remove slag, cool down to 720℃, and under argon protection, mix the preheated aluminum strontium master alloy, aluminum cerium master alloy, aluminum scandium master alloy, aluminum yttrium master alloy, and aluminum erbium master alloy and press them into the aluminum alloy melt in one go using a bell jar. The preheating temperature is 300℃ and the time is 3 hours. Stir for 4 minutes and let stand for 12 minutes to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The molten liquid obtained in step S3 is subjected to semi-continuous casting. The casting speed is 60 mm / min, the cooling water flow rate is 40 L / min, and the casting temperature is 715℃, to obtain ingot A. S5. The ingot A obtained in step S4 is subjected to homogenization treatment, which includes: primary homogenization treatment, secondary homogenization treatment and heat preservation treatment in sequence; the temperature of primary homogenization treatment is 465℃ and the heat preservation time is 5h; the temperature of secondary homogenization treatment is 495℃ and the heat preservation time is 3h; the temperature of heat preservation treatment is 525℃ and the heat preservation time is 4h; and hot water quenching is used to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment at a temperature of 180℃ for 6 hours to obtain a high impact-resistant aluminum alloy.

[0030] The mass ratio of aluminum alloy melt to refining agent is 1:0.0025.

[0031] The refining agent is a combination of sodium-free refining agent and lanthanum cerium chloride, with a mass ratio of 1:0.35.

[0032] Example 2 A high-impact aluminum alloy, by weight percentage, comprises the following components: silicon 0.03%; copper 4.2%; chromium 0.01%; magnesium 0.8%; zinc 0.05%; manganese 0.7%; niobium 0.15%; strontium 0.01%; zirconium 0.08%; titanium 0.01%; rare earth elements 0.2%; impurity iron 0.10%; other impurity elements 0.05%; the balance being aluminum; the rare earth elements include cerium, scandium, yttrium, and erbium, in a weight ratio of 1:0.55:0.25:0.25.

[0033] The preparation method of the high impact-resistant aluminum alloy in this embodiment includes the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 740℃ to obtain aluminum alloy melt. S2. Add refining agent to the aluminum alloy melt obtained in step S1, adjust the temperature to 730℃, degas with argon for 20 minutes, remove slag, cool down to 715℃, and under argon protection, mix the preheated aluminum-strontium master alloy, aluminum-cerium master alloy, aluminum-scandium master alloy, aluminum-yttrium master alloy, and aluminum-erbium master alloy and press them into the aluminum alloy melt in one go using a bell jar. The preheating temperature is 250℃ and the time is 4 hours. Stir for 5 minutes and let stand for 10 minutes to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The molten liquid obtained in step S3 is subjected to semi-continuous casting. The casting speed is 50 mm / min, the cooling water flow rate is 35 L / min, and the casting temperature is 710℃ to obtain ingot A. S5. The ingot A obtained in step S4 is subjected to homogenization treatment, which includes: primary homogenization treatment, secondary homogenization treatment and heat preservation treatment. The temperature of primary homogenization treatment is 460℃ and the heat preservation time is 6h. The temperature of secondary homogenization treatment is 490℃ and the heat preservation time is 4h. The temperature of heat preservation treatment is 520℃ and the heat preservation time is 5h. Hot water quenching is then performed to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment at a temperature of 170℃ for 7 hours to obtain a high impact-resistant aluminum alloy.

[0034] The mass ratio of aluminum alloy melt to refining agent is 1:0.002.

[0035] The refining agent is a combination of sodium-free refining agent and lanthanum cerium chloride, with a mass ratio of 1:0.2.

[0036] Example 3 A high-impact-resistant aluminum alloy, by weight percentage, comprises the following components: silicon 0.15%; copper 4.4%; chromium 0.05%; magnesium 1.0%; zinc 0.08%; manganese 0.9%; niobium 0.25%; strontium 0.05%; zirconium 0.12%; titanium 0.05%; rare earth elements 0.25%; impurity iron 0.10%; other impurity elements 0.05%; the balance being aluminum; the rare earth elements include cerium, scandium, yttrium, and erbium, with a mass ratio of 1:0.65:0.35:0.35.

[0037] The preparation method of the high impact-resistant aluminum alloy in this embodiment includes the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 750℃ to obtain an aluminum alloy melt. S2. Add refining agent to the aluminum alloy melt obtained in step S1, adjust the temperature to 740℃, degas with argon for 30 minutes, remove slag, cool down to 725℃, and under argon protection, mix the preheated aluminum strontium master alloy, aluminum cerium master alloy, aluminum scandium master alloy, aluminum yttrium master alloy, and aluminum erbium master alloy and press them into the aluminum alloy melt in one go using a bell jar. The preheating temperature is 350℃ and the time is 2 hours. Stir for 3 minutes and let stand for 15 minutes to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The molten liquid obtained in step S3 is subjected to semi-continuous casting. The casting speed is 70 mm / min, the cooling water flow rate is 45 L / min, and the casting temperature is 720℃, to obtain ingot A. S5. The ingot A obtained in step S4 is subjected to homogenization treatment, which includes: primary homogenization treatment, secondary homogenization treatment and heat preservation treatment in sequence; the temperature of primary homogenization treatment is 470℃ and the heat preservation time is 4h; the temperature of secondary homogenization treatment is 500℃ and the heat preservation time is 2h; the temperature of heat preservation treatment is 530℃ and the heat preservation time is 3h; and hot water quenching is used to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment at a temperature of 190℃ for 5 hours to obtain a high impact-resistant aluminum alloy.

[0038] The mass ratio of aluminum alloy melt to refining agent is 1:0.0028.

[0039] The refining agent is a combination of sodium-free refining agent and lanthanum cerium chloride, with a mass ratio of 1:0.5.

[0040] Example 4 A high-impact-resistant aluminum alloy and its preparation method are disclosed. The specific implementation method is the same as in Example 1, except that the refining agent is a sodium-free refining agent.

[0041] Example 5 A high-impact-resistant aluminum alloy and its preparation method are disclosed. The specific implementation method is the same as in Example 1, except that the refining agent is sodium chloride.

[0042] Example 6 A high-impact-resistant aluminum alloy and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the mass ratio of sodium-free refining agent and mixed rare earth chloride is 1:0.7.

[0043] Example 7 A high-impact-resistant aluminum alloy and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the rare earth elements include cerium, scandium, yttrium and erbium, and the mass ratio of the four elements is 1:0.6:0.1:0.3.

[0044] Comparative Example 1 A high-impact aluminum alloy, by weight percentage, comprises the following components: silicon 0.09%; copper 4.3%; chromium 0.03%; magnesium 0.9%; zinc 0.06%; manganese 0.8%; niobium 0.2%; strontium 0.03%; zirconium 0.1%; titanium 0.03%; rare earth elements 0.23%; impurity iron 0.10%; the balance being aluminum; wherein the rare earth elements include cerium, scandium, yttrium, and erbium, in a mass ratio of 1:0.6:0.3:0.3.

[0045] The preparation method of the high impact-resistant aluminum alloy in this embodiment includes the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 745℃ to obtain an aluminum alloy melt. S2. Under argon protection, the preheated aluminum-strontium master alloy, aluminum-cerium master alloy, aluminum-scandium master alloy, aluminum-yttrium master alloy, and aluminum-erbium master alloy are mixed and pressed into the aluminum alloy melt obtained in step S1 in one go using a bell jar. The preheating temperature is 300℃ and the time is 3h. Stir for 4min, let stand for 12min, add refining agent, adjust the temperature to 735℃, use argon to degas for 25min, remove slag, and cool down to 720℃ to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The molten liquid obtained in step S3 is subjected to semi-continuous casting. The casting speed is 60 mm / min, the cooling water flow rate is 40 L / min, and the casting temperature is 715℃, to obtain ingot A. S5. The ingot A obtained in step S4 is subjected to homogenization treatment, which includes: primary homogenization treatment, secondary homogenization treatment and heat preservation treatment in sequence; the temperature of primary homogenization treatment is 465℃ and the heat preservation time is 5h; the temperature of secondary homogenization treatment is 495℃ and the heat preservation time is 3h; the temperature of heat preservation treatment is 525℃ and the heat preservation time is 4h; and hot water quenching is used to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment at a temperature of 180℃ for 6 hours to obtain a high impact-resistant aluminum alloy.

[0046] The mass ratio of aluminum alloy melt to refining agent is 1:0.0025.

[0047] The refining agent is a composition of sodium-free refining agent and mixed rare earth chloride, with a mass ratio of 1:0.35.

[0048] Comparative Example 2 A high-impact-resistant aluminum alloy and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the rare earth elements include cerium, scandium and yttrium, and the mass ratio of the three is 1:0.6:0.3.

[0049] Comparative Example 3 The aluminum alloy used in this comparative example is commercially available 6061 aluminum alloy.

[0050] Performance testing The aluminum alloys obtained in each embodiment and comparative example were tested: (1) Strength: The tensile strength and yield strength of each specimen were tested in accordance with GB / T 228.1-2021 "Metallic materials, tensile testing - Part 1: Test method at room temperature".

[0051] Impact resistance: The impact absorption energy of each specimen was tested in accordance with GB / T 229-2020 "Metallic Materials Charpy Pendulum Impact Test Method" to characterize its impact resistance.

[0052] The test results are shown in Table 1: Table 1 As shown in Table 1, the aluminum alloys of Examples 1-3 of this invention possess both high specific strength and excellent impact resistance. A comparison between Example 4 and Example 1 shows that when the refining agent does not contain lanthanum and cerium chloride, both the strength and impact resistance of the aluminum alloy decrease. A comparison between Example 5 and Example 1 shows that when the refining agent is sodium chloride, the strength and impact resistance of the aluminum alloy are poor. A comparison between Example 6 and Example 1 shows that changing the ratio of sodium-free refining agent and mixed rare earth chlorides may cause unreacted or reacted mixed rare earth chlorides, due to their low density, to remain in the melt, forming high-melting-point, brittle chloride inclusions, leading to the aluminum alloy's... The strength and impact resistance deteriorate. A comparison between Example 7 and Example 1 shows that changing the proportions of rare earth elements weakens their grain-refining effect, leading to a decrease in the strength and impact resistance of the aluminum alloy. A comparison between Comparative Example 1 and Example 1 shows that changing the order of addition of the refining agent and rare earth master alloy easily results in the loss of rare earth elements, thus worsening the strength and impact resistance of the aluminum alloy. A comparison between Comparative Example 2 and Example 1 shows that the strength and impact resistance decrease to some extent when erbium is not present in the aluminum alloy. A comparison between Comparative Example 3 and Example 1 shows that although commercially available 6061 aluminum alloys have high strength, their impact resistance is poor.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-impact-resistant aluminum alloy, characterized in that, Based on 100% by mass, it contains the following components: silicon 0.03-0.15%; copper 4.2-4.4%; chromium 0.01-0.05%; magnesium 0.8-1.0%; zinc 0.05-0.08%; manganese 0.7-0.9%; niobium 0.15-0.25%; strontium 0.01-0.05%; zirconium 0.08-0.12%; titanium 0.01-0.05%; rare earth elements 0.2-0.25%; impurity iron <0.12%; other impurity elements <0.1%; the balance is aluminum; the rare earth elements include cerium, scandium, yttrium, and erbium.

2. The high impact-resistant aluminum alloy according to claim 1, characterized in that, The mass ratio of cerium, scandium, yttrium, and erbium is 1:(0.55-0.65):(0.25-0.35):(0.25-0.35).

3. A method for preparing a high-impact-resistant aluminum alloy according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Add aluminum-silicon master alloy, aluminum-copper master alloy, aluminum-chromium master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, aluminum-niobium master alloy, industrial pure magnesium, industrial pure zinc, and industrial pure aluminum into a melting furnace and melt them at a melting temperature of 740-750℃ to obtain aluminum alloy melt. S2. Add refining agent to the aluminum alloy melt obtained in step S1, adjust the temperature to 730-740℃, degas with inert gas for 20-30 minutes, remove slag, cool to 715-725℃, and under argon protection, mix the preheated aluminum-strontium master alloy, aluminum-cerium master alloy, aluminum-scandium master alloy, aluminum-yttrium master alloy, and aluminum-erbium master alloy and press them into the aluminum alloy melt in one go using a bell jar. Stir for 3-5 minutes, let stand for 10-15 minutes to obtain the alloy melt. S3. Perform pre-furnace composition analysis on the alloy melt obtained in step S2, detect the composition content of the alloy melt, and make the composition content of the melt that is not up to standard by adding material or diluting it to reach the standard range, thus obtaining the melt. S4. The melt obtained in step S3 is subjected to semi-continuous casting to obtain ingot A; S5. Homogenize the ingot A obtained in step S4 and quench it in hot water to obtain ingot B. S6. The ingot B obtained in step S5 is subjected to aging heat treatment to obtain a high impact-resistant aluminum alloy.

4. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The mass ratio of the aluminum alloy melt to the refining agent in step S2 is 1:(0.002-0.0028).

5. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The refining agent is a composition of sodium-free refining agent and mixed rare earth chloride, with a mass ratio of 1:(0.2-0.5).

6. The method for preparing the high impact-resistant aluminum alloy according to claim 5, characterized in that, The mixed rare earth chlorides are lanthanum and cerium chlorides.

7. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The preheating temperature in step S2 is 250-350℃, and the time is 2-4 hours.

8. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The casting speed in step S3 is 50-70 mm / min, the cooling water flow rate is 35-45 L / min, and the casting temperature is 710-720℃.

9. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The homogenization process in step S5 includes, in sequence: a primary homogenization process, a secondary homogenization process, and a heat preservation process; the temperature of the primary homogenization process is 460-470℃, and the heat preservation time is 4-6h; the temperature of the secondary homogenization process is 490-500℃, and the heat preservation time is 2-4h; the temperature of the heat preservation process is 520-530℃, and the heat preservation time is 3-5h.

10. The method for preparing the high impact-resistant aluminum alloy according to claim 3, characterized in that, The aging heat treatment in step S6 is performed at a temperature of 170-190℃ for 5-7 hours.

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