A heat treatment free high-strength and high-toughness die-casting aluminum alloy and a production process thereof

Abstract

The application relates to the alloy technical field and discloses a heat-treatment-free high-strength and high-toughness aluminum alloy and a production process thereof, which is prepared from magnesium, copper, manganese, cadmium, scandium, titanium, zinc, a toughening component and aluminum as raw materials and by adopting a heat-treatment-free process. The toughening component is a graphene-aluminum complex. In the smelting process, the toughening component can form an intercalation type mechanical stable structure with the aluminum alloy matrix. Meanwhile, alumina has good affinity with the aluminum melt, thereby generating a small amount of Al4C3 strengthening grains. The heat-treatment-free high-strength and high-toughness aluminum alloy not only can effectively avoid the problem that the interface delamination between the aluminum alloy and the graphene leads to the reduction of the strength of the aluminum alloy, but also can improve the internal organizational structure of the aluminum alloy, so that the strength and plasticity of the aluminum alloy are enhanced, and the production cost is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the alloy technical field, in particular to a heat treatment-free high-strength and high-toughness aluminum alloy and a production process thereof. BACKGROUND

[0002] In recent years, new energy vehicles have developed rapidly, and the endurance is the biggest factor restricting the sales of new energy vehicles. Since the weight of the battery accounts for a large proportion in new energy vehicles, the overall weight of the vehicle body is difficult to control, which seriously affects the endurance of the battery. Therefore, the lightweight design of new energy vehicles is particularly important. Die-cast aluminum alloy has the characteristics of light weight and high strength and is widely used in the manufacturing field of new energy vehicle structural parts. At present, die-cast aluminum alloy basically needs to adopt a solid solution and aging heat treatment process to improve the strength and toughness of the aluminum alloy. However, the heat treatment process can cause bending deformation and other phenomena of large automobile structural parts, which leads to the fact that die-cast aluminum alloy gradually cannot meet the actual industrial demand and is disconnected with the market.

[0003] In recent years, heat treatment-free die-cast aluminum alloy has been researched. The patent with the publication number CN114438380B discloses a heat treatment-free high-toughness AlSi aluminum alloy and a preparation method thereof. On the basis of not changing the conventional aluminum alloy die-casting production process, the high-toughness AlSi aluminum alloy die-casting product is obtained by innovatively improving the aspects of melt refining, modification and refinement. Therefore, the heat treatment-free process needs to be combined with the improvement of other processes or formulations to enable the prepared aluminum alloy to have excellent strength and toughness. SUMMARY

[0004] The application aims to provide a heat treatment-free high-strength and high-toughness aluminum alloy and a production process thereof, and solves the problem that the aluminum alloy material needs to be subjected to a heat treatment process to have high strength and high toughness.

[0005] The object of the application can be achieved by the following technical solutions.

[0006] A heat treatment-free high-strength and high-toughness die-cast aluminum alloy comprises the following raw materials in percentage by mass: magnesium 2.0-3.5%, copper 1.0-1.5%, manganese 0.1-0.2%, cadmium 0.2-0.3%, scandium 0.5-1.0%, titanium 0.05-0.08%, zinc 4.0-5.2%, a toughening component 1.5-2.0%, and the balance being aluminum.

[0007] The toughening component is a graphene-aluminum complex.

[0008] Further, the preparation method of the toughening component comprises the following steps:

[0009] Step A: take graphene oxide, ultrasonic dispersion in a mixture of methanol and N, N- dimethylformamide solution, continue to add carboxyethyl silane triol sodium salt, after adding, increase the temperature to 50-60℃, keep for 12-16h, stop heating, cool down, centrifugal, wash with ethanol, nitric acid and deionized water to neutral, vacuum drying, obtain graphene oxide intermediate;

[0010] Step B: ultrasonic dispersion of graphene oxide intermediate in toluene, add aluminum-containing material and oxalic acid, mechanical stirring, increase the temperature to 90-95℃, keep stirring for 1-2h, cool down, centrifugal, wash and vacuum drying, obtain graphene-aluminum complex, namely toughening component.

[0011] Further, in step A, the volume ratio of methanol and N, N-dimethylformamide is 4-5:1.

[0012] Further, in step B, the mass ratio of graphene oxide intermediate, aluminum-containing material and oxalic acid is 1:1.5-2:0.4-0.8.

[0013] Further, in step B, the aluminum-containing material is any one of aluminum chloride hexahydrate or aluminum isopropylate.

[0014] In the above technical solution, the surface of graphene oxide is modified by carboxyethyl silane triol sodium salt, a large number of active carboxyl groups are formed on the surface of graphene oxide, and graphene oxide intermediate is prepared. Because carboxyl groups can coordinate with aluminum ions, a three-dimensional graphene-aluminum complex with aluminum ions as the coordination center, namely the toughening component, is formed.

[0015] A production process of a heat treatment-free high-strength and high-toughness die-casting aluminum alloy includes the following steps:

[0016] Step one: prepare ingredients according to mass percentage;

[0017] Step two: place aluminum and titanium in a furnace, increase the furnace temperature to 500-600℃, keep the temperature for 1-1.5h, then increase the furnace temperature to 780-800℃, add the toughening component, keep the temperature for 1-2h, add copper, manganese, cadmium and zinc, keep the temperature for 1-2h, reduce the furnace temperature to 750-760℃, add magnesium, keep the temperature for 5-15min, then increase the furnace temperature to 760-770℃, add scandium, keep the temperature for 5-15min, obtain an aluminum alloy mixed solution;

[0018] Step three: degas and slag the aluminum alloy mixed solution, remove the floating dregs, pour out of the furnace, pour into a mold, and die-cast to obtain a high-strength and high-toughness die-casting aluminum alloy.

[0019] Further, in step three, the mold temperature is maintained at 200-250 DEG C and the pouring temperature is 650-700 DEG C during the die casting.

[0020] The beneficial effects of the present application are:

[0021] In the melting process, graphene oxide can be thermally reduced, and aluminum can be oxidized into aluminum oxide, further forming a three-dimensional graphene-aluminum oxide composite. In the three-dimensional graphene structure, there are gaps, and aluminum melt can enter the gaps to form an intercalated mechanical stable structure with three-dimensional graphene. At the same time, aluminum oxide has good affinity with aluminum melt, thereby generating a small amount of Al4C3 strengthening grains. This not only effectively avoids the problem of interface delamination between aluminum alloy and graphene, which leads to the reduction of aluminum alloy strength, but also improves the internal structure of aluminum alloy, thereby enhancing the strength and plasticity of aluminum alloy.

[0022] By adding alloying elements such as magnesium, copper, manganese, cadmium, titanium, zinc, and silicon elements contained in the reinforcing component in the aluminum alloy matrix, various high-strength compounds can be generated by reacting with aluminum. The scandium element can refine the grains and improve the strength of the aluminum alloy. Therefore, by utilizing the synergistic effect of various metal elements and the toughening component, the aluminum alloy still has good strength and toughness without heat treatment, greatly reducing energy consumption and production cost.

[0023] Of course, implementing any product of the present application does not necessarily require all the advantages described above. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] Embodiment 1

[0026] A heat-treatment-free high-strength and high-toughness die-casting aluminum alloy, by mass percentage, comprises the following raw materials: magnesium 2.0%, copper 1.0%, manganese 0.1%, cadmium 0.2%, scandium 0.5%, titanium 0.05%, zinc 4.0%, toughening component 1.5%, and the balance being aluminum.

[0027] The preparation method of the die-casting aluminum alloy comprises the following steps:

[0028] Step one: batching according to mass percentage, ready for use;

[0029] Step two: place aluminum and titanium in the furnace, raise the furnace temperature to 500℃, after constant temperature treatment for 1h, raise the furnace temperature to 780℃, add toughening component, after adding, keep constant temperature treatment for 1h, add copper, manganese, cadmium, zinc, keep constant temperature treatment for 1h, reduce the furnace temperature to 750℃, add magnesium, after adding, keep at this temperature environment for 5min, then raise the furnace temperature to 760℃, add scandium, keep constant temperature treatment for 5min, obtain aluminum alloy mixed solution;

[0030] Step three: after degassing and slagging of the aluminum alloy mixed solution, remove the floating dregs, take out the furnace, pour into the mold, control the mold temperature to be 200℃, the pouring temperature to be 650℃, and pressure casting is formed, then high-strength and high-toughness pressure casting aluminum alloy is obtained.

[0031] Example 2

[0032] A heat treatment-free high-strength and high-toughness pressure casting aluminum alloy, by mass percentage, comprises the following raw materials: magnesium 2.8%, copper 1.2%, manganese 0.2%, cadmium 0.3%, scandium 0.8%, titanium 0.06%, zinc 5.0%, toughening component 1.8%, and the balance is aluminum.

[0033] The preparation method of the pressure casting aluminum alloy comprises the following steps:

[0034] Step one: prepare the raw materials according to the mass percentage;

[0035] Step two: place aluminum and titanium in the furnace, raise the furnace temperature to 580℃, after constant temperature treatment for 1h, raise the furnace temperature to 790℃, add toughening component, after adding, keep constant temperature treatment for 2h, add copper, manganese, cadmium, zinc, keep constant temperature treatment for 2h, reduce the furnace temperature to 760℃, add magnesium, after adding, keep at this temperature environment for 10min, then raise the furnace temperature to 770℃, add scandium, keep constant temperature treatment for 10min, obtain aluminum alloy mixed solution;

[0036] Step three: after degassing and slagging of the aluminum alloy mixed solution, remove the floating dregs, take out the furnace, pour into the mold, control the mold temperature to be 240℃, the pouring temperature to be 670℃, and pressure casting is formed, then high-strength and high-toughness pressure casting aluminum alloy is obtained.

[0037] Example 3

[0038] A heat treatment-free high-strength and high-toughness pressure casting aluminum alloy, by mass percentage, comprises the following raw materials: magnesium 3.5%, copper 1.5%, manganese 0.2%, cadmium 0.3%, scandium 1.0%, titanium 0.08%, zinc 5.2%, toughening component 2.0%, and the balance is aluminum.

[0039] The preparation method of the pressure casting aluminum alloy comprises the following steps:

[0040] Step one: ingredient according to mass percentage, standby;

[0041] Step two: put aluminum and titanium into the furnace, raise the furnace temperature to 600℃, after 1.5h of constant temperature treatment at this temperature, raise the furnace temperature to 800℃, add the toughening component, after adding, keep warm for 2h, add copper, manganese, cadmium, zinc, keep warm for 2h, reduce the furnace temperature to 760℃, add magnesium, after adding, keep at this temperature environment for 15min, then raise the furnace temperature to 770℃, add scandium, keep warm for 15min, obtain aluminum alloy mixed solution;

[0042] Step three: after degassing and slagging of the aluminum alloy mixed solution, remove the floating dregs, take out the furnace, pour into the mold, control the mold temperature to be 250℃, the pouring temperature to be 700℃, and pressure casting is formed, then high-strength and high-toughness pressure casting aluminum alloy is obtained.

[0043] The toughening component in the above examples is prepared by the following steps:

[0044] Step A: take 3g of graphene oxide, ultrasonically disperse in a mixed solution of methanol and N,N-dimethylformamide with a volume ratio of 4:1, continue to add 5mL of carboxyethyl silane triol sodium salt (25wt.%, aqueous solution), after adding, warm up to 60℃, keep warm for 16h, then stop heating, cool down and discharge, centrifuge the solid material, wash with ethanol, nitric acid and deionized water in turn until neutral, vacuum drying, obtain graphene oxide intermediate;

[0045] Step B: ultrasonically disperse 2g of graphene oxide intermediate in toluene, add 3.6g of aluminum chloride hexahydrate and 1.2g of oxalic acid, mechanically stir uniformly, then raise the temperature of the system to 90℃, keep stirring at constant temperature for 2h, then cool down and discharge, centrifuge the solid product, after washing and vacuum drying treatment, obtain graphene-aluminum complex, that is, the toughening component.

[0046] Comparative example 1

[0047] A kind of pressure casting aluminum alloy, according to mass percentage, includes the following raw materials: magnesium 2.8%, copper 1.2%, manganese 0.2%, cadmium 0.3%, scandium 0.8%, titanium 0.06%, zinc 5.0%, graphene 1.8%, and the balance is aluminum;

[0048] The preparation method of the pressure casting aluminum alloy includes the following steps:

[0049] Step one: ingredient according to mass percentage, standby;

[0050] Step two: place aluminum and titanium in the furnace, raise the furnace temperature to 580℃, after constant temperature treatment for 1h at this temperature, raise the furnace temperature to 790℃, add graphene, after adding, keep temperature for 2h, add copper, manganese, cadmium, zinc, keep temperature for 2h, reduce the furnace temperature to 760℃, add magnesium, after adding, keep temperature for 10min, then raise the furnace temperature to 770℃, add scandium, keep temperature for 10min, obtain an aluminum alloy mixed solution;

[0051] Step three: after degassing and slagging of the aluminum alloy mixed solution, remove the floating dregs, take out the furnace, pour into the mold, control the mold temperature to be 240℃, the pouring temperature to be 670℃, and the pressure casting is formed, then the pressure casting aluminum alloy is obtained.

[0052] Comparative example 2

[0053] A kind of pressure casting aluminum alloy, by mass percentage, comprising the following raw materials: magnesium 2.8%, copper 1.2%, manganese 0.2%, cadmium 0.3%, scandium 0.8%, titanium 0.06%, zinc 5.0%, and the balance is aluminum;

[0054] The preparation method of the pressure casting aluminum alloy comprises the following steps:

[0055] Step one: batching according to mass percentage, standby;

[0056] Step two: place aluminum and titanium in the furnace, raise the furnace temperature to 580℃, after constant temperature treatment for 1h at this temperature, raise the furnace temperature to 790℃, add copper, manganese, cadmium, zinc, keep temperature for 2h, reduce the furnace temperature to 760℃, add magnesium, after adding, keep temperature for 10min, then raise the furnace temperature to 770℃, add scandium, keep temperature for 10min, obtain an aluminum alloy mixed solution;

[0057] Step three: after degassing and slagging of the aluminum alloy mixed solution, remove the floating dregs, take out the furnace, pour into the mold, control the mold temperature to be 240℃, the pouring temperature to be 670℃, and the pressure casting is formed, then the pressure casting aluminum alloy is obtained.

[0058] Performance detection

[0059] According to the national standard GB / T 228.1-2021, the performance of the pressure casting aluminum alloy prepared by the inventive examples 1-3 and the comparative examples 1-2 is tested, the tensile speed is set to 2mm / min, and the test results are recorded in the following table:

[0060]

[0061]

[0062] It can be analyzed by testing that the prepared die-casting aluminum alloy added with the toughening component has high strength and high toughness, and the strength and toughness of the die-casting aluminum alloy prepared in Comparative Example 1 and Comparative Example 2 without adding the toughening component are obviously decreased. The die-casting aluminum alloy prepared in Comparative Example 1 is added with graphene, and the effect of reinforcement and toughening is not obvious due to the delamination between the graphene and the aluminum alloy matrix.

[0063] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description 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 appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0064] The above is only an example and description of the concept of the present application, and those skilled in the art can make various modifications or supplements or replace with similar ways, as long as it does not deviate from the concept of the application or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A heat-treatment-free high-strength high-ductility die-cast aluminum alloy, characterized by comprising, in mass %, By mass percent, the following raw materials are included: magnesium 2.0-3.5%, copper 1.0-1.5%, manganese 0.1-0.2%, cadmium 0.2-0.3%, scandium 0.5-1.0%, titanium 0.05-0.08%, zinc 4.0-5.2%, toughening component 1.5-2.0%, and the balance being aluminum; The toughening component is a graphene-aluminum complex; The preparation method of the toughening component includes the following steps: Step A: take graphene oxide, ultrasonically disperse in a mixed solution of methanol and N,N-dimethylformamide, continue to add sodium carboxyethyl silane triol salt, after adding, warm to 50-60℃, keep warm for 12-16h, then stop heating, cool down and discharge, centrifuge the solid material, wash with ethanol, nitric acid and deionized water in sequence until neutral, vacuum drying, to obtain graphene oxide intermediate; Step B: ultrasonically disperse the graphene oxide intermediate in toluene, add aluminum-containing substance and oxalic acid, mechanically stir uniformly, then raise the temperature of the system to 90-95℃, keep constant temperature and stir for 1-2h, then cool down and discharge, centrifuge the solid product, after washing and vacuum drying, obtain graphene-aluminum complex, i.e. the toughening component.

2. The heat-treatment free high-strength and high-ductility die-casting aluminum alloy according to claim 1, characterized in that, In step A, the volume ratio of methanol and N,N-dimethylformamide is 4-5:

1.

3. The heat-treatment free high-strength and high-ductility die-casting aluminum alloy according to claim 1, characterized in that, In step B, the mass ratio of graphene oxide intermediate, aluminum-containing substance and oxalic acid is 1:1.5-2:0.4-0.

8.

4. The heat-treatment free high-strength and high-ductility die-casting aluminum alloy according to claim 1, characterized in that, In step B, the aluminum-containing substance is any one of aluminum chloride hexahydrate or aluminum isopropylate.

5. A production process for a heat-free, high-strength, high-toughness die-cast aluminum alloy as described in claim 1, characterized in that, The following steps are included: Step one: prepare the ingredients by mass percent, for standby; Step two: place aluminum and titanium in a furnace, raise the furnace temperature to 500-600℃, keep constant temperature for 1-1.5h, then raise the furnace temperature to 780-800℃, add the toughening component, after adding, keep warm for 1-2h, add copper, manganese, cadmium, zinc, keep constant temperature for 1-2h, reduce the furnace temperature to 750-760℃, add magnesium, after adding, keep at this temperature environment for 5-15min, then raise the furnace temperature to 760-770℃, add scandium, keep warm for 5-15min, to obtain an aluminum alloy mixed solution; Step three: after degassing and slagging the aluminum alloy mixed solution, remove the floating dross, discharge from the furnace, pour into a mold, and pressure cast to form, to obtain high-strength and high-toughness die-casting aluminum alloy.

6. The process for producing a heat-treatment free high-strength high-ductility die casting aluminum alloy according to claim 5, characterized in that, In step three, the mold temperature is maintained at 200-250℃ during pressure casting, and the pouring temperature is 650-700℃.

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