High-toughness light-weight structural part die-casting aluminum alloy and preparation method thereof

Abstract

The invention relates to the technical field of aluminum alloy production, in particular to a high-toughness lightweight structural part die-casting aluminum alloy and a preparation method thereof. The high-toughness light-weight structural part die-casting aluminum alloy is prepared from the following raw materials in parts by weight: 5 to 7 parts of magnesium, 0.1 to 0.5 part of silicon, 0.2 to 0.4 part of copper, 0.1 to 0.4 part of iron, 0.05 to 0.1 part of zinc, 0.05 to 0.1 part of composite material and 50 to 70 parts of aluminum material, the high-toughness light-weight structural part die-casting aluminum alloy prepared through the method not only has the good tensile strength performance, but also has the excellent yield strength and elongation performance, meanwhile, recycling of waste aluminum products can be achieved, and the production cost is reduced.

Description

Technical Field

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

[0002] Aluminum alloy is an alloy with aluminum as the base and a certain amount of other alloying elements added. It is one of the light metal materials. It can be used as a structural material and has a wide range of applications in aerospace, aviation, transportation, construction, electromechanics, 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 remainder 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 the 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] Although the aluminum alloy manufactured by the above patent document has certain advantages such as tensile strength, its own mechanical properties are relatively insufficient and the production cost is high, and further improvement is still needed. Based on this, the present invention provides a high-strength and lightweight structural die-casting aluminum alloy and a preparation method thereof to solve the above technical problems. 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 and lightweight structural die-casting aluminum alloy, 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 composite materials and 50 to 70 parts of aluminum materials;

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

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

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

[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 slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, 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-casting 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 as follows: the aluminum material is selected from waste aluminum products.

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

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

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

[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 slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, 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-casting 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 the 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 the 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, 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 slag-beating 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 slag-breaking agent.

[0028] The present invention is further configured as follows: in step S4, the process of the solid 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] Stage 1: treatment at 125°C 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] In the present invention, magnesium, silicon, copper, iron, zinc, composite material and aluminum material are used as raw materials, and magnesium, silicon, copper, iron, zinc, composite material and aluminum material are accurately weighed, and the aluminum material is preheated, and then placed in a smelting furnace for smelting, and then magnesium, silicon, copper, iron, zinc and composite material are added thereto, and hexachloroethane is added and slowly stirred, and then the temperature is raised for smelting, and then a slag remover is evenly spread on the liquid surface, and the slag on the liquid surface is removed, and poured into a mold preheated at 200°C to obtain an aluminum alloy ingot, and the obtained aluminum alloy ingot is solution treated under nitrogen protection, and after the solution treatment is completed, an aging treatment is performed, and quenched in greenhouse water to obtain a high-toughness and lightweight structural die-casting aluminum alloy. The high-toughness and lightweight structural die-casting 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, it can realize the reuse of discarded aluminum products, reducing production costs. The high-strength and toughness lightweight structural die-casting 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a high-strength and lightweight structural die-cast aluminum alloy, 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 material;

[0039] The composite material is a mixture 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 light-weight structural die-casting aluminum alloy, comprising the following steps:

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

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

[0044] The preheating temperature is 210°C.

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

[0046] S3. Then add magnesium, silicon, copper, iron, zinc and composite materials, add hexachloroethane and stir slowly for 2 minutes, heat up for melting, evenly spread slag remover on the liquid surface, let it stand for 20 minutes, scrape off the slag on the liquid surface, pour 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 increased to 740°C at a heating rate of 2°C / min, the smelting time is 40min, and the slag remover is composed of the following raw materials 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 slag-beating 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 slag-breaking agent.

[0051] S4. Under nitrogen protection, subjecting the obtained aluminum alloy ingot to solid solution treatment.

[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°C for 6 hours.

[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-casting aluminum alloy.

[0056] The process of aging treatment is as follows:

[0057] Stage 1: treatment at 125°C 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-casting aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that: the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are different; the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are as follows:

[0061] A high-strength and lightweight structural die-casting aluminum alloy, which is composed of the following raw materials 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 composite material and 52 parts of aluminum;

[0062] The composite material is a mixture 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 light-weight structural die-casting aluminum alloy, comprising the following steps:

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

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

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

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

[0069] S3. Then add magnesium, silicon, copper, iron, zinc and composite materials, add hexachloroethane and stir slowly for 3 minutes, heat up for melting, and then evenly spread slag remover on the liquid surface. Let it stand for 20 to 24 minutes, scrape off the slag on the liquid surface, and pour it 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 increased to 742°C at a heating rate of 3°C / min, the smelting time is 42min, and the slag remover is composed of the following raw materials 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 slag-beating 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 slag-breaking agent.

[0074] S4. Under nitrogen protection, subjecting the obtained aluminum alloy ingot to solid solution treatment.

[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°C for 6 hours.

[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-casting aluminum alloy.

[0079] The process of aging treatment is as follows:

[0080] Stage 1: treatment at 125°C 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-casting aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that: the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are different; the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are as follows:

[0084] A high-strength and lightweight structural die-casting aluminum alloy, which is composed of the following raw materials in parts by weight: 6 parts of magnesium, 0.3 parts of silicon, 0.3 parts of copper, 0.3 parts of iron, 0.07 parts of zinc, 0.07 parts of composite material and 60 parts of aluminum;

[0085] The composite material is a mixture 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 light-weight structural die-casting aluminum alloy, comprising the following steps:

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

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

[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, then the temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface, and the mixture is allowed to stand for 22 minutes. The slag on the liquid surface is scraped off, and 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, the smelting time is 45min, and 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 slag-beating 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 slag-breaking agent.

[0097] S4. Under nitrogen protection, subjecting the obtained aluminum alloy ingot to solid solution treatment.

[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°C for 6 hours.

[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-casting aluminum alloy.

[0102] The process of aging treatment is as follows:

[0103] Stage 1: treatment at 125°C 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-casting aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that: the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are different; the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are as follows:

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

[0108] The composite material is a mixture 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 light-weight structural die-casting aluminum alloy, comprising the following steps:

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

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

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

[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, then the temperature is raised for melting, and then a slag remover is evenly spread on the liquid surface, and the mixture is allowed to stand for 23 minutes. The slag on the liquid surface is scraped off, and 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, the smelting time is 48 minutes, and 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 slag-beating 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 slag-breaking agent.

[0120] S4. Under nitrogen protection, subjecting the obtained aluminum alloy ingot to solid solution treatment.

[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°C for 6 hours.

[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-casting aluminum alloy.

[0125] The process of aging treatment is as follows:

[0126] Stage 1: treatment at 125°C 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-casting aluminum alloy provided in this embodiment is basically the same as that in Example 1, except that: the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are different; the specific raw material composition and the specific preparation method of the high-strength and toughness lightweight structural die-casting aluminum alloy in this embodiment are as follows:

[0130] A high-strength and lightweight structural die-casting aluminum alloy, which is composed of the following raw materials by weight: 7 parts of magnesium, 0.5 parts of silicon, 0.4 parts of copper, 0.4 parts of iron, 0.1 parts of zinc, 0.1 parts of composite material and 70 parts of 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 light-weight structural die-casting aluminum alloy, comprising the following steps:

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

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

[0136] The preheating temperature is 220°C.

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

[0138] S3. Then add magnesium, silicon, copper, iron, zinc and composite materials, add hexachloroethane and stir slowly for 5 minutes, heat up for melting, evenly spread slag remover on the liquid surface, let it stand for 24 minutes, scrape off the slag on the liquid surface, pour 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 increased to 760°C at a heating rate of 5°C / min, the smelting time is 50min, and 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 slag-beating 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 slag-breaking agent.

[0143] S4. Under nitrogen protection, subjecting the obtained aluminum alloy ingot to solid solution treatment.

[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°C for 6 hours.

[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-casting aluminum alloy.

[0148] The process of aging treatment is as follows:

[0149] Stage 1: treatment at 125°C 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 to replace 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 after the solution treatment in this example, the sample is quenched in hothouse 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 test: The test method is to perform room temperature stretching on an electronic tensile testing machine with a stretching rate of 2mm / 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] By comparing and analyzing the relevant data in Table 1, it can be seen that 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. At the same time, it can achieve the recycling of discarded aluminum products and reduce production costs. This shows that the high-strength and toughness lightweight structural die-cast aluminum alloy and the preparation method thereof provided by the present invention have a broader market prospect and are more suitable for promotion.

[0165] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0166] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-strength and lightweight structural die-casting 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 material; The preparation process of the high-strength and lightweight structural die-casting aluminum alloy is as follows: S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set them aside; S2, preheating the aluminum material, and then placing it in a smelting furnace for smelting; 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 slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, 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-casting aluminum alloy.

2. The high-strength and lightweight structural die-casting aluminum alloy according to claim 1, characterized in that: The composite material is prepared by mixing nickel and vanadium in a mass ratio of 1:0.2-0.

6.

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

4. A method for preparing a high-strength and light-weight structural die-casting aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Accurately weigh magnesium, silicon, copper, iron, zinc, composite materials and aluminum materials and set them aside; S2, preheating the aluminum material, and then placing it in a smelting furnace for smelting; 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 slag remover on the liquid surface, standing for 20 to 24 minutes, scraping off the slag on the liquid surface, 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-casting aluminum alloy.

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

6. The method for preparing a high-strength and lightweight structural die-casting aluminum alloy according to claim 4, characterized in that: In the step S2, the smelting temperature is 750-760°C and the smelting time is 60-70 minutes.

7. The method for preparing a high-strength and light-weight structural die-casting aluminum alloy according to claim 4, characterized in that: In the 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, the smelting time is 40-50min, 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; The preparation process of the slag-beating 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 slag-breaking agent.

8. The method for preparing a high-strength and light-weight structural die-casting aluminum alloy according to claim 4, 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.

9. The method for preparing a high-strength and light-weight structural die-casting aluminum alloy according to claim 4, characterized in that: In step S5, the aging treatment process is as follows: Stage 1: treatment at 125°C for 5h; The second stage: treatment at 175°C for 4 hours.