A high-strength and lightweight structural die-cast aluminum alloy and its preparation method

Abstract

The present invention relates to the technical field of aluminum alloy production, and specifically relates to a high-strength and toughness lightweight structural die-cast aluminum alloy and a preparation method thereof; the high-strength and toughness lightweight structural die-cast aluminum alloy is composed of the following raw materials in parts by weight: 5 to 7 parts of magnesium, 0.1 to 0.5 parts of silicon, 0.2 to 0.4 parts of copper, 0.1 to 0.4 parts of iron, 0.05 to 0.1 parts of zinc, 0.05 to 0.1 parts of a composite material, and 50 to 70 parts of an aluminum material; the high-strength and toughness lightweight structural die-cast aluminum alloy prepared by the present invention not only has good tensile strength performance, but also has excellent yield strength and elongation performance, and at the same time, can realize the reuse of discarded aluminum products, thereby reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy production, and in particular to a high-strength, toughness, and lightweight structural die-casting aluminum alloy and a preparation method thereof. Background Art

[0002] Aluminum alloys are aluminum-based alloys with a certain amount of other alloying elements added. They are one of the lightest metal materials. They can be used as structural materials and have a wide range of applications in aerospace, aviation, transportation, construction, electromechanical, light chemicals, and daily necessities.

[0003] In the patent document with application number "CN202210473463.4" and name "High-strength and toughness lightweight structural parts die-casting aluminum alloy production process", it is recorded that "the present invention uses titanium ingots and aluminum-copper intermediate alloy rods as raw materials, and its main components are Ti: 38-42wt%, Al: 50-55wt%, Cu: 5.2-6.7wt%, Si <0.8wt%, and the balance is inevitable impurities. The addition of Cu promotes the formation of atomic clusters. The solute atomic clusters interact with slip dislocations, and their effect is similar to that of second-phase particles, which can strengthen the aluminum alloy; a homemade refining agent is used in the smelting process, which uses zeolite particles as a carrier and is loaded with nano-scale zero-valent iron and tantalum powder. The zero-valent iron combines with oxygen in the alloy liquid, and the tantalum powder absorbs hydrogen to generate TaHx, which floats up together with the slag, effectively removing oxygen and hydrogen in the alloy liquid, reducing pores and inclusions, and is conducive to the formation of dense castings."

[0004] While the aluminum alloys described in the aforementioned patents possess advantages such as tensile strength, their mechanical properties are relatively insufficient and their production costs are high, requiring further improvement. The present invention therefore provides a high-strength, lightweight die-cast aluminum alloy for structural parts and a method for its preparation to address the aforementioned technical issues. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength and toughness lightweight structural die-cast aluminum alloy and a preparation method thereof. The prepared high-strength and toughness lightweight structural die-cast aluminum alloy not only has good tensile strength performance, but also has excellent yield strength and elongation performance. At the same time, it can realize the reuse of discarded aluminum products and reduce production costs.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, which is composed of the following raw materials in parts by weight: 5 to 7 parts of magnesium, 0.1 to 0.5 parts of silicon, 0.2 to 0.4 parts of copper, 0.1 to 0.4 parts of iron, 0.05 to 0.1 parts of zinc, 0.05 to 0.1 parts of a composite material, and 50 to 70 parts of aluminum.

[0008] The preparation process of the high-strength and lightweight structural die-cast aluminum alloy is as follows:

[0009] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite material and aluminum material and set aside;

[0010] S2, preheating the aluminum material, and then placing it in a melting furnace for melting;

[0011] S3, then adding magnesium, silicon, copper, iron, zinc and composite materials, adding hexachloroethane and slowly stirring for 2 to 5 minutes, heating and melting, and then evenly spreading a slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, and pouring into a mold preheated at 200° C. to obtain an aluminum alloy ingot;

[0012] S4, subjecting the obtained aluminum alloy ingot to solid solution treatment under nitrogen protection;

[0013] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0014] The present invention is further configured as follows: the composite material is formed by mixing nickel and vanadium in a mass ratio of 1:0.2 to 0.6.

[0015] The present invention is further configured such that: the aluminum material is selected from waste aluminum products.

[0016] The second aspect of the present invention further provides a method for preparing the above-mentioned high-strength and lightweight structural die-cast aluminum alloy, comprising the following steps:

[0017] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite material and aluminum material and set aside;

[0018] S2, preheating the aluminum material, and then placing it in a melting furnace for melting;

[0019] S3, then adding magnesium, silicon, copper, iron, zinc and composite materials, adding hexachloroethane and slowly stirring for 2 to 5 minutes, heating and melting, and then evenly spreading a slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, and pouring into a mold preheated at 200° C. to obtain an aluminum alloy ingot;

[0020] S4, subjecting the obtained aluminum alloy ingot to solid solution treatment under nitrogen protection;

[0021] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0022] The present invention is further configured as follows: in step S2, the preheating temperature is 210-220°C.

[0023] The present invention is further configured as follows: in step S2, the smelting temperature is 750-760° C., and the smelting time is 60-70 minutes.

[0024] The present invention is further configured as follows: in step S3, the amount of hexachloroethane added is 0.8-1.2% of the mass of the aluminum material, the temperature is increased to 740-760° C. at a heating rate of 2-5° C. / min, and the smelting time is 40-50 min, and the slag remover is composed of the following raw materials in parts by weight: 20-30 parts of silicon dioxide, 15-20 parts of aluminum oxide, 5-7 parts of potassium chloride, 4-8 parts of magnesium chloride, 8-10 parts of sodium fluoride, and 6-10 parts of sodium fluorosilicate;

[0025] The preparation process of the slagging agent is as follows:

[0026] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0027] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 340-460 r / min for 20-30 minutes to obtain a slagging agent.

[0028] The present invention is further configured as follows: in step S4, the process of the solution treatment is as follows:

[0029] The first stage: treatment at 520℃ for 10h;

[0030] The second stage: treatment at 545°C for 6 minutes.

[0031] The present invention is further configured as follows: in step S5, the aging treatment process is as follows:

[0032] The first stage: treatment at 125℃ for 5h;

[0033] The second stage: treatment at 175°C for 4 hours.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention uses magnesium, silicon, copper, iron, zinc, composite material and aluminum material as raw materials, and accurately weighs magnesium, silicon, copper, iron, zinc, composite material and aluminum material, preheats the aluminum material, then places it in a smelting furnace for smelting, then adds magnesium, silicon, copper, iron, zinc and composite material, and adds hexachloroethane and slowly stirs, heats up and smelts, then evenly spreads a slag remover on the liquid surface, stands, scrapes off the slag on the liquid surface, and pours it into a mold preheated to 200°C to obtain an aluminum alloy ingot, and under nitrogen protection, the obtained aluminum alloy ingot is solution treated, after the solution treatment is completed, it is aged and quenched in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy. The high-strength and lightweight structural die-cast aluminum alloy prepared by the present invention not only has good tensile strength performance, but also has excellent yield strength and elongation performance. At the same time, it can achieve the reuse of discarded aluminum products, reducing production costs. The high-strength and toughness lightweight structural die-cast aluminum alloy and the preparation method thereof provided by the present invention have broader market prospects and are more suitable for promotion. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, which is composed of the following raw materials in parts by weight: 5 parts of magnesium, 0.1 parts of silicon, 0.2 parts of copper, 0.1 parts of iron, 0.05 parts of zinc, 0.05 parts of composite material, and 50 parts of aluminum;

[0039] The composite material is made of nickel and vanadium in a mass ratio of 1:0.2.

[0040] Aluminum materials are selected from waste aluminum products.

[0041] In addition, this embodiment also provides a method for preparing the above-mentioned high-strength and lightweight structural part die-cast aluminum alloy, comprising the following steps:

[0042] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside.

[0043] S2. Preheat the aluminum material and then place it in a melting furnace for melting.

[0044] The preheating temperature is 210°C.

[0045] The melting temperature is 750°C and the melting time is 60 minutes.

[0046] S3. Then, magnesium, silicon, copper, iron, zinc and composite materials are added thereto, and hexachloroethane is added and slowly stirred for 2 minutes. Then, the temperature is raised for melting, and a slag remover is evenly spread on the liquid surface. The mixture is allowed to stand for 20 minutes, and the slag on the liquid surface is scraped off. The mixture is poured into a mold preheated at 200°C to obtain an aluminum alloy ingot.

[0047] The amount of hexachloroethane added is 0.8% of the mass of the aluminum material. The temperature is raised to 740°C at a heating rate of 2°C / min for 40 minutes. The slag remover is composed of the following raw materials in parts by weight: 20 parts of silicon dioxide, 15 parts of aluminum oxide, 5 parts of potassium chloride, 4 parts of magnesium chloride, 8 parts of sodium fluoride, and 6 parts of sodium fluorosilicate.

[0048] The preparation process of the slagging agent is as follows:

[0049] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0050] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 340 r / min for 20 minutes to obtain a slagging agent.

[0051] S4. Under nitrogen protection, the obtained aluminum alloy ingot is solution treated.

[0052] The process of solution treatment is as follows:

[0053] The first stage: treatment at 520℃ for 10h;

[0054] The second stage: treatment at 545℃ for 6h.

[0055] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0056] The aging process is as follows:

[0057] The first stage: treatment at 125℃ for 5h;

[0058] The second stage: treatment at 175°C for 4 hours.

[0059] Example 2

[0060] The preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are different; the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are as follows:

[0061] A high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, comprising the following raw materials in parts by weight: 6 parts of magnesium, 0.2 parts of silicon, 0.3 parts of copper, 0.2 parts of iron, 0.06 parts of zinc, 0.06 parts of a composite material, and 52 parts of aluminum;

[0062] The composite material is made of nickel and vanadium in a mass ratio of 1:0.3.

[0063] Aluminum materials are selected from waste aluminum products.

[0064] In addition, this embodiment also provides a method for preparing the above-mentioned high-strength and lightweight structural part die-cast aluminum alloy, comprising the following steps:

[0065] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside.

[0066] S2. Preheat the aluminum material and then place it in a melting furnace for melting.

[0067] Among them, the preheating temperature is 212℃.

[0068] The smelting temperature is 752°C and the smelting time is 62 minutes.

[0069] S3. Then, magnesium, silicon, copper, iron, zinc and composite materials are added thereto, and hexachloroethane is added and slowly stirred for 3 minutes. The temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface. The mixture is allowed to stand for 20 to 24 minutes, and the slag on the liquid surface is scraped off. The mixture is poured into a mold preheated at 200°C to obtain an aluminum alloy ingot.

[0070] The amount of hexachloroethane added is 0.9% of the mass of the aluminum material. The temperature is raised to 742°C at a heating rate of 3°C / min for 42 minutes. The slag remover is composed of the following raw materials in parts by weight: 22 parts of silicon dioxide, 16 parts of aluminum oxide, 6 parts of potassium chloride, 5 parts of magnesium chloride, 9 parts of sodium fluoride, and 7 parts of sodium fluorosilicate.

[0071] The preparation process of the slagging agent is as follows:

[0072] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0073] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 342 r / min for 22 minutes to obtain a slagging agent.

[0074] S4. Under nitrogen protection, the obtained aluminum alloy ingot is solution treated.

[0075] The process of solution treatment is as follows:

[0076] The first stage: treatment at 520℃ for 10h;

[0077] The second stage: treatment at 545℃ for 6h.

[0078] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0079] The aging process is as follows:

[0080] The first stage: treatment at 125℃ for 5h;

[0081] The second stage: treatment at 175°C for 4 hours.

[0082] Example 3

[0083] The preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are different; the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are as follows:

[0084] A high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, comprising the following raw materials in parts by weight: 6 parts magnesium, 0.3 parts silicon, 0.3 parts copper, 0.3 parts iron, 0.07 parts zinc, 0.07 parts composite material, and 60 parts aluminum;

[0085] The composite material is made of nickel and vanadium in a mass ratio of 1:0.4.

[0086] Aluminum materials are selected from waste aluminum products.

[0087] In addition, this embodiment also provides a method for preparing the above-mentioned high-strength and lightweight structural part die-cast aluminum alloy, comprising the following steps:

[0088] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside.

[0089] S2. Preheat the aluminum material and then place it in a melting furnace for melting.

[0090] The preheating temperature is 215°C.

[0091] The melting temperature is 755°C and the melting time is 65 minutes.

[0092] S3. Then, magnesium, silicon, copper, iron, zinc and composite materials are added thereto, and hexachloroethane is added and slowly stirred for 3 minutes. The temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface. The mixture is allowed to stand for 22 minutes, and the slag on the liquid surface is scraped off. The mixture is poured into a mold preheated at 200°C to obtain an aluminum alloy ingot.

[0093] The amount of hexachloroethane added is 1% of the mass of the aluminum material, the temperature is increased to 750°C at a heating rate of 3°C / min, and the smelting time is 45 minutes. The slag remover is composed of the following raw materials in parts by weight: 25 parts of silicon dioxide, 17 parts of aluminum oxide, 6 parts of potassium chloride, 6 parts of magnesium chloride, 9 parts of sodium fluoride, and 8 parts of sodium fluorosilicate;

[0094] The preparation process of the slagging agent is as follows:

[0095] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0096] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 350 r / min for 25 minutes to obtain a slagging agent.

[0097] S4. Under nitrogen protection, the obtained aluminum alloy ingot is solution treated.

[0098] The process of solution treatment is as follows:

[0099] The first stage: treatment at 520℃ for 10h;

[0100] The second stage: treatment at 545℃ for 6h.

[0101] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0102] The aging process is as follows:

[0103] The first stage: treatment at 125℃ for 5h;

[0104] The second stage: treatment at 175°C for 4 hours.

[0105] Example 4

[0106] The preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are different; the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are as follows:

[0107] A high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, comprising the following raw materials in parts by weight: 6 parts magnesium, 0.4 parts silicon, 0.3 parts copper, 0.3 parts iron, 0.09 parts zinc, 0.09 parts composite material, and 62 parts aluminum;

[0108] The composite material is made of nickel and vanadium in a mass ratio of 1:0.5.

[0109] Aluminum materials are selected from waste aluminum products.

[0110] In addition, this embodiment also provides a method for preparing the above-mentioned high-strength and lightweight structural part die-cast aluminum alloy, comprising the following steps:

[0111] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside.

[0112] S2. Preheat the aluminum material and then place it in a melting furnace for melting.

[0113] Among them, the preheating temperature is 218℃.

[0114] The smelting temperature is 758°C and the smelting time is 68 minutes.

[0115] S3. Then, magnesium, silicon, copper, iron, zinc and composite materials are added thereto, and hexachloroethane is added and slowly stirred for 4 minutes. The temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface. The mixture is allowed to stand for 23 minutes, and the slag on the liquid surface is scraped off. The mixture is poured into a mold preheated at 200°C to obtain an aluminum alloy ingot.

[0116] The amount of hexachloroethane added is 1.1% of the mass of the aluminum material. The temperature is increased to 755°C at a heating rate of 4°C / min, and the smelting time is 48 minutes. The slag remover is composed of the following raw materials in parts by weight: 28 parts of silicon dioxide, 19 parts of aluminum oxide, 6 parts of potassium chloride, 7 parts of magnesium chloride, 9 parts of sodium fluoride, and 9 parts of sodium fluorosilicate.

[0117] The preparation process of the slagging agent is as follows:

[0118] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0119] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 355 r / min for 28 minutes to obtain a slagging agent.

[0120] S4. Under nitrogen protection, the obtained aluminum alloy ingot is solution treated.

[0121] The process of solution treatment is as follows:

[0122] The first stage: treatment at 520℃ for 10h;

[0123] The second stage: treatment at 545℃ for 6h.

[0124] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0125] The aging process is as follows:

[0126] The first stage: treatment at 125℃ for 5h;

[0127] The second stage: treatment at 175°C for 4 hours.

[0128] Example 5

[0129] The preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are different; the specific raw material composition and specific preparation method of the high-strength and toughness lightweight structural die-cast aluminum alloy in this embodiment are as follows:

[0130] A high-strength, tough, and lightweight die-cast aluminum alloy for structural parts, comprising the following raw materials in parts by weight: 7 parts magnesium, 0.5 parts silicon, 0.4 parts copper, 0.4 parts iron, 0.1 parts zinc, 0.1 parts composite material, and 70 parts aluminum;

[0131] The composite material is a mixture of nickel and vanadium in a mass ratio of 1:0.6.

[0132] Aluminum materials are selected from waste aluminum products.

[0133] In addition, this embodiment also provides a method for preparing the above-mentioned high-strength and lightweight structural part die-cast aluminum alloy, comprising the following steps:

[0134] S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside.

[0135] S2. Preheat the aluminum material and then place it in a melting furnace for melting.

[0136] The preheating temperature is 220°C.

[0137] The melting temperature is 760°C and the melting time is 70 minutes.

[0138] S3. Then, magnesium, silicon, copper, iron, zinc and composite materials are added thereto, and hexachloroethane is added and slowly stirred for 5 minutes. The temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface. The mixture is allowed to stand for 24 minutes, and the slag on the liquid surface is scraped off. The mixture is poured into a mold preheated at 200°C to obtain an aluminum alloy ingot.

[0139] The amount of hexachloroethane added is 1.2% of the mass of the aluminum material. The temperature is raised to 760°C at a heating rate of 5°C / min, and the smelting time is 50 minutes. The slag remover is composed of the following raw materials in parts by weight: 30 parts of silicon dioxide, 20 parts of aluminum oxide, 7 parts of potassium chloride, 8 parts of magnesium chloride, 10 parts of sodium fluoride, and 10 parts of sodium fluorosilicate.

[0140] The preparation process of the slagging agent is as follows:

[0141] Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate;

[0142] Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 460 r / min for 30 minutes to obtain a slagging agent.

[0143] S4. Under nitrogen protection, the obtained aluminum alloy ingot is solution treated.

[0144] The process of solution treatment is as follows:

[0145] The first stage: treatment at 520℃ for 10h;

[0146] The second stage: treatment at 545℃ for 6h.

[0147] S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

[0148] The aging process is as follows:

[0149] The first stage: treatment at 125℃ for 5h;

[0150] The second stage: treatment at 175°C for 4 hours.

[0151] Comparative Example 1: The difference from Example 1 is that in this example, an equal amount of industrial aluminum is used instead of waste aluminum products.

[0152] Comparative Example 2: The difference from Example 1 is that the first stage of the solution treatment in this example is: treatment at 510° C. for 10 h.

[0153] Comparative Example 3: The difference from Example 1 is that the first stage of the solution treatment in this example is: treatment at 530° C. for 10 hours.

[0154] Comparative Example 4: The difference from Example 1 is that the second stage of the solution treatment in this example is: treatment at 530° C. for 6 hours.

[0155] Comparative Example 5: The difference from Example 1 is that the second stage of the solution treatment in this example is: treatment at 550°C for 6 hours.

[0156] Comparative Example 6: The difference from Example 1 is that the aging treatment in this example does not include the first stage.

[0157] Comparative Example 7: The difference from Example 1 is that the aging treatment in this example does not include a second stage.

[0158] Comparative Example 8: The difference from Example 1 is that in this example, after the solution treatment is completed, the steel is quenched in hot water and then subjected to aging treatment.

[0159] Performance test: The die-cast aluminum alloy samples provided in Examples 1 to 5 and Comparative Examples 1 to 8 are marked as Examples 1 to 5 and Comparative Examples 1 to 8, respectively; and the relevant properties of the die-cast aluminum alloys provided in Examples 1 to 5 and Comparative Examples 1 to 8 are tested as follows:

[0160] Mechanical testing: The test method is to perform room temperature stretching on an electronic tensile testing machine with a stretching rate of 2 mm / min to detect the tensile strength, yield strength and elongation of the die-cast aluminum alloy.

[0161] The obtained test data are recorded in Table 1 below:

[0162] Table 1 Mechanical properties test results of each group of cast aluminum alloys

[0163] Group Tensile strength (MPa) Yield strength (MPa) Elongation (MPa) Example 1 group 552 445 6.5 Example 2 group 550 443 6.4 Example 3 group 549 442 6.4 Example 4 group 551 443 6.5 Example 5 group 554 446 6.6 Comparison group 1 551 442 6.5 Comparison of 2 groups 498 422 4.7 Comparison of 3 groups 505 425 5.1 Comparison of 4 groups 512 429 5.3 Comparison of 5 groups 505 426 5.1 Comparison of 6 groups 519 432 5.5 Comparison of 7 groups 522 434 5.6 Comparison of 8 groups 534 438 6.0

[0164] Comparison and analysis of the relevant data in Table 1 show that the high-strength, toughness, lightweight structural die-cast aluminum alloy prepared by the present invention not only has good tensile strength but also excellent yield strength and elongation. Furthermore, it can reuse discarded aluminum products, reducing production costs. This demonstrates that the high-strength, toughness, lightweight structural die-cast aluminum alloy and its preparation method provided by the present invention have broader market prospects and are more suitable for promotion.

[0165] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0166] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-strength and lightweight structural die-cast aluminum alloy, characterized in that: The invention is composed of the following raw materials in parts by weight: 5 to 7 parts of magnesium, 0.1 to 0.5 parts of silicon, 0.2 to 0.4 parts of copper, 0.1 to 0.4 parts of iron, 0.05 to 0.1 parts of zinc, 0.05 to 0.1 parts of composite material and 50 to 70 parts of aluminum; The composite material is made of nickel and vanadium in a mass ratio of 1:0.2 to 0.6; The preparation process of the high-strength and lightweight structural die-cast aluminum alloy is as follows: S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set aside; S2, preheating the aluminum material, and then placing it in a melting furnace for melting; S3, then adding magnesium, silicon, copper, iron, zinc and composite materials, adding hexachloroethane and slowly stirring for 2 to 5 minutes, heating and melting, and then evenly spreading a slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, and pouring into a mold preheated at 200° C. to obtain an aluminum alloy ingot; S4, subjecting the obtained aluminum alloy ingot to solid solution treatment under nitrogen protection; S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

2. The high-strength and lightweight structural die-cast aluminum alloy according to claim 1, characterized in that: The aluminum material is selected from waste aluminum products.

3. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite material and aluminum material and set aside; S2, preheating the aluminum material, and then placing it in a melting furnace for melting; S3, then adding magnesium, silicon, copper, iron, zinc and composite materials, adding hexachloroethane and slowly stirring for 2 to 5 minutes, heating and melting, and then evenly spreading a slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, and pouring into a mold preheated at 200° C. to obtain an aluminum alloy ingot; S4, subjecting the obtained aluminum alloy ingot to solid solution treatment under nitrogen protection; S5. After the solution treatment is completed, aging treatment is performed and quenching is performed in greenhouse water to obtain a high-strength and lightweight structural die-cast aluminum alloy.

4. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to claim 3, characterized in that: In step S2, the preheating temperature is 210-220°C.

5. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to claim 3, characterized in that: In the step S2, the smelting temperature is 750-760°C and the smelting time is 60-70 minutes.

6. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to claim 3, characterized in that: In step S3, the amount of hexachloroethane added is 0.8-1.2% of the mass of the aluminum material, the temperature is raised to 740-760° C. at a heating rate of 2-5° C. / min, and the smelting time is 40-50 min. The slag remover is composed of the following raw materials in parts by weight: 20-30 parts of silicon dioxide, 15-20 parts of aluminum oxide, 5-7 parts of potassium chloride, 4-8 parts of magnesium chloride, 8-10 parts of sodium fluoride, and 6-10 parts of sodium fluorosilicate; The preparation process of the slagging agent is as follows: Accurately weigh silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate; Silicon dioxide, aluminum oxide, potassium chloride, magnesium chloride, sodium fluoride and sodium fluorosilicate are placed in a mixing device and mixed at 340-460 r / min for 20-30 minutes to obtain a slagging agent.

7. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to claim 3, characterized in that: In step S4, the process of the solution treatment is as follows: The first stage: treatment at 520℃ for 10h; The second stage: treatment at 545°C for 6 minutes.

8. The method for preparing a high-strength and lightweight structural die-cast aluminum alloy according to claim 3, characterized in that: In step S5, the aging treatment process is as follows: The first stage: treatment at 125℃ for 5h; The second stage: treatment at 175°C for 4 hours.