Heat-treatable aluminum alloy material, preparation method thereof, and application thereof

Abstract

The present invention discloses a heat-treatable aluminum alloy material, its preparation method and applications, belonging to the technical field of alloys. The heat-treatable aluminum alloy material comprises the following elemental components by mass percentage: Si 7.5% - 8.5%, Mg 0.4% - 0.8%, Cu 0.6% - 0.7%, Zn 0.1% - 0.4%, Mn 0.4% - 0.8%, Fe 0 - 0.4%, Ca 0.13% - 0.25%, Sr 0.015% - 0.050%, Ti 0.05% - 0.30%, V 0.03% - 0.05%, RE 0.05% - 0.2%, inevitable impurities < 0.03%, and Al as the balance. The RE element is La and / or Ce. On the premise of ensuring excellent fluidity of its molten liquid, the aluminum alloy material also has excellent strength and toughness characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and particularly to a heat-treatable aluminum alloy material, its preparation method and application. Background Art

[0002] Aluminum alloy die-castings based on aluminum alloy materials have the characteristics of integration, light weight, high toughness, etc., and are usually used to prepare structural parts of automobiles, which is more beneficial for the lightweight design of automobiles.

[0003] Al-Si series aluminum alloy materials have excellent casting performance and are more suitable for preparing structural parts of automobiles. In particular, heat-treatable Al-Si series aluminum alloy materials are also beneficial for reducing production costs. However, for the currently known heat-treatable Al-Si series aluminum alloy materials, their strength and toughness still need to be improved. Summary of the Invention

[0004] In view of this, the present invention provides a heat-treatable aluminum alloy material, its preparation method and application, which can solve the technical problems existing in the related art.

[0005] Specifically, the following technical solutions are included:

[0006] On the one hand, a heat-treatable aluminum alloy material is provided. The heat-treatable aluminum alloy material includes the following elemental components by mass percentage: Si 7.5%-8.5%, Mg 0.4%-0.8%, Cu 0.6%-0.7%, Zn 0.1%-0.4%, Mn 0.4%-0.8%, Fe 0-0.4%, Ca 0.13%-0.25%, Sr 0.015%-0.050%, Ti 0.05%-0.30%, V 0.03%-0.05%, RE 0.05%-0.2%, unavoidable impurities <0.03%, and Al as the balance, where the RE element is La and / or Ce.

[0007] In some possible implementation manners, the mass ratio of the Si element to the Ca element is 40-65:1.

[0008] In some possible implementation manners, the mass ratio of the Si element to the total mass of the Ca element, V element and RE element is 20-35:1.

[0009] In some possible implementation manners, the mass percentage of the Ca element is 0.15%-0.19%.

[0010] On the other hand, a preparation method of a heat-treatable aluminum alloy material is provided, and the heat-treatable aluminum alloy material is as described in any one of the above;

[0011] The preparation method of the heat-treatable aluminum alloy material includes: providing preparation raw materials according to the mass percentages of the elements in the heat-treatable aluminum alloy material;

[0012] Performing smelting treatment, slag skimming treatment, and die-casting treatment on the preparation raw materials in sequence to prepare the heat-treatable aluminum alloy material.

[0013] In some possible implementation manners, at least part of the raw materials in the preparation raw materials are selected from aluminum scrap.

[0014] In some possible implementation manners, the aluminum scrap includes at least one of 1-series aluminum alloy scrap, 5-series aluminum alloy scrap, 6-series aluminum alloy scrap, A356 aluminum alloy scrap, A380 aluminum alloy scrap, AlSi7Mg0.3Cu0.5 aluminum alloy scrap, and AlSi9Cu3 aluminum alloy scrap.

[0015] In some possible implementation manners, in the preparation raw materials, the Ca element is added in the form of Al-10Ca alloy; at least part of the Si element is added in the form of Al-20Si alloy; at least part of the Mg element is added in the form of pure Mg; at least part of the Mn element is added in the form of Al-20Mn alloy; at least part of the Cu element is added in the form of Al-50Cu alloy; at least part of the Zn element is added in the form of Al-20Zn alloy; at least part of the V element is added in the form of Al-5V alloy; at least part of the Ti element is added in the form of Al-10Ti alloy, and at least part of the Sr element is added in the form of Al-10Sr alloy.

[0016] In some possible implementation manners, the providing preparation raw materials according to the mass percentages of the elements in the heat-treatable aluminum alloy material includes:

[0017] Classifying, crushing, and impurity removing the aluminum scrap in sequence to obtain aluminum scrap raw materials and use them as the first part of the preparation raw materials;

[0018] After determining the first part of the preparation raw materials, determining and providing the second part of the preparation raw materials according to the formula of the heat-treatable aluminum alloy material;

[0019] Performing batching on the first part of the preparation raw materials and the second part of the preparation raw materials according to the mass percentages of the elements in the heat-treatable aluminum alloy material to obtain the preparation raw materials.

[0020] In some possible implementation manners, the performing smelting treatment, slag skimming treatment, and die-casting treatment on the preparation raw materials in sequence to prepare the heat-treatable aluminum alloy material includes:

[0021] The raw materials for preparing the first part are successively subjected to melting treatment and dross removal treatment to obtain a first raw material melt;

[0022] The components contained in the raw materials for preparing the second part are added to the first raw material melt in a stepwise manner and subjected to melting treatment to obtain an aluminum alloy melt;

[0023] The aluminum alloy melt is subjected to die-casting treatment to prepare the heat-treatable aluminum alloy material.

[0024] On the other hand, the embodiments of the present invention also provide an application of the heat-treatable aluminum alloy material in the preparation of aluminum alloy structural parts, where the heat-treatable aluminum alloy material is as described in any of the above, or is prepared by the preparation method of the heat-treatable aluminum alloy material described in any of the above.

[0025] On the other hand, the embodiments of the present invention also provide an aluminum alloy structural part, which is prepared by a heat-treatable aluminum alloy material, where the heat-treatable aluminum alloy material is as described in any of the above, or is prepared by the preparation method of the heat-treatable aluminum alloy material described in any of the above.

[0026] The beneficial effects of the technical solutions provided by the embodiments of the present invention at least include:

[0027] The heat-treatable aluminum alloy material provided by the embodiments of the present invention includes the following elemental components by mass percentage: Si 7.5%-8.5%, Mg 0.4%-0.8%, Cu 0.6%-0.7%, Zn 0.1%-0.4%, Mn 0.4%-0.8%, Fe 0-0.4%, Ca 0.15%-0.25%, Sr 0.015%-0.050%, Ti 0.05%-0.30%, V 0.03%-0.05%, RE 0.05%-0.2%, unavoidable impurities <0.03%, and Al as the balance, where the RE element is La and / or Ce. By selecting specific types of elements and combining them in specific mass percentages, the components act synergistically. On the one hand, this helps to reduce the liquidus temperature of the aluminum alloy material and improve the fluidity of the aluminum alloy melt, thereby ensuring the filling ability of the aluminum alloy material and being more conducive to forming by an integrated die-casting process. On the other hand, this helps to improve the strength, toughness, deformation resistance and other properties of the aluminum alloy material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is the microstructure image of the aluminum alloy die-casting part corresponding to Example 3;

[0030] Figure 2 It is the SEM image of the aluminum alloy die-casting part corresponding to Example 3 under a certain resolution condition;

[0031] Figure 3 It is the SEM image of the aluminum alloy die-casting part corresponding to Example 3 under another resolution condition.

[0032] Through the above-mentioned drawings, specific embodiments of the present invention have been shown, and there will be more detailed descriptions hereinafter. These drawings and text descriptions are not intended to limit the scope of the inventive concept in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] In recent years, under the requirements of the dual-carbon goal, people have increasingly realized the importance of energy conservation and emission reduction for the sustainable development of mankind. In the automotive industry, there is analysis data showing that for every 10% reduction in vehicle weight, vehicle fuel consumption can be reduced by 6% - 8%, and emissions can be reduced by 4%; for new energy vehicles, a 100 Kg reduction in weight can increase the driving range by 10 - 11%, and can also reduce battery costs by 20% and daily loss costs by 20%. Therefore, the issue of vehicle lightweighting has gradually become an urgent need for the development of the automotive industry.

[0035] Due to its light weight, aluminum alloy materials are increasingly used in automobiles. Especially aluminum die-castings, due to their advantages such as integration, lightweight, and high toughness, have been continuously promoted in automotive applications. This requires continuous improvement in the integration level of die-castings. Traditional AlSi10MnMg alloys are difficult to meet the requirements due to the necessity of heat treatment, thus new heat-treatment-free die-casting aluminum alloy materials are needed. At the same time, the automotive industry has an increasing demand for integrated die-casting technology.

[0036] The casting performance of Al-Si series aluminum alloy materials is relatively excellent and is more suitable for preparing structural parts of automobiles. In particular, the heat-treatment-free Al-Si series aluminum alloy materials are also beneficial to reducing production costs. However, for the currently known heat-treatment-free Al-Si series aluminum alloy materials, their strength and toughness still need to be improved, making it difficult to meet the requirements of integrated die-cast automobile structures.

[0037] On the one hand, embodiments of the present invention provide a heat-treatment-free aluminum alloy material, which includes the following elemental components by mass percentage: Si 7.5%-8.5%, Mg 0.4%-0.8%, Cu 0.6%-0.7%, Zn 0.1%-0.4%, Mn 0.4%-0.8%, Fe 0-0.4%, Ca 0.15%-0.25%, Sr 0.015%-0.050%, Ti 0.05%-0.30%, V 0.03%-0.05%, RE 0.05%-0.2%, unavoidable impurities <0.03%, and Al as the balance, where the RE element is La and / or Ce.

[0038] Regarding the above-mentioned heat-treatment-free aluminum alloy material, the functions of each elemental component in it will be described first.

[0039] In the embodiments of the present invention, the mass percentage of the Si element is 7.5%-8.5%, which includes but is not limited to the following point values and the interval ranges formed by any two point values: 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, etc.

[0040] The Si element can not only increase the strength of the aluminum alloy material but also ensure the casting fluidity of the aluminum alloy material. Based on the above mass percentage of the Si element, the aluminum alloy involved in the embodiments of the present invention is a medium-silicon-content aluminum alloy, which is usually suitable for preparing structural parts with higher strength requirements but relatively moderate elongation rates. For example, it is applied to the front section position, rear section position, etc. of the three-section integrated die-cast structural parts.

[0041] The mass percentage of Mg element is 0.4% - 0.8%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, etc.

[0042] Under die-casting conditions, a part of the Mg element will dissolve into the aluminum alloy matrix to increase the matrix strength, and another part of the Mg element can precipitate a second phase (such as Mg2Si, etc.) in the eutectic region, thereby enhancing the strength of the aluminum alloy.

[0043] The mass percentage of Cu element is 0.6% - 0.7%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, etc.

[0044] Under die-casting conditions, a part of the Cu element will dissolve into the matrix to increase the matrix strength, and another part of the Cu element precipitates a strengthening phase (such as Al2Cu) at the eutectic region to enhance the strength of the aluminum alloy. The Cu element with the above mass percentage can also improve the casting fluidity of the aluminum alloy material, compensating for the problem of reduced fluidity caused by a low silicon content.

[0045] The mass percentage of Zn element is 0.1% - 0.4%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, etc.

[0046] During the solidification process, Zn elements can be enriched on the surfaces of the Al-Si-Cu-Mg phase and the Fe-containing phase, inhibiting their growth, reducing the sizes of the Al-Si-Cu-Mg phase and the Fe-containing phase, and thus significantly improving the as-cast properties of the aluminum alloy material. Moreover, during the aging process, due to the increased solid solubility of Zn elements in the α-Al phase, Zn elements are dissolved into α-Al, which has a solid solution strengthening effect and is beneficial to increasing the strength of the aluminum alloy material. The mass percentage of Zn elements within the above range and their synergistic effect with other component elements are more beneficial to optimizing the as-cast properties and strength of the aluminum alloy material.

[0047] The mass percentage of Mn elements is 0.4% - 0.8%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.8%, etc.

[0048] Mn elements with the above mass percentage can not only control the acicular Fe phase, reduce the harm of the Fe phase, but also help improve the demolding performance of the aluminum alloy material.

[0049] The mass percentage of Fe elements is 0 - 0.4%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.4%, etc.

[0050] During the solidification process, Fe elements are likely to jointly form acicular β-Fe phases with elements such as Al and Si. During the stress process, stress concentration is likely to occur, thereby splitting the matrix and deteriorating the performance of the aluminum alloy material. Therefore, in the embodiments of the present invention, it is expected that the mass percentage of Fe elements is less than or equal to 0.4% to avoid deteriorating the performance of the alloy material.

[0051] The mass percentage of Ca elements is 0.13% - 0.25%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, etc.

[0052] In the embodiments of the present invention, by adding 0.13% - 0.25% of Ca elements to the aluminum alloy material, on the one hand, the Ca elements play the role of heterogeneous nucleation sites, which is conducive to increasing the nucleation of primary Al grains. Moreover, the Ca elements with the above mass percentage can smoothly form the second phase with other elements while refining the grains, ultimately achieving the purpose of improving the strength and toughness of the aluminum alloy material.

[0053] Furthermore, the mass percentage of Ca elements can be 0.15% - 0.19% to further optimize the strength and toughness of the aluminum alloy material.

[0054] The mass percentage of Sr elements is 0.015% - 0.050%, which includes but is not limited to the following point values and the range of intervals formed by any two point values: 0.015%, 0.016%, 0.017%, 0.018%, 0.019%, 0.02%, 0.021%, 0.022%, 0.023%, 0.024%, 0.025%, 0.026%, 0.027%, 0.028%, 0.029%, 0.03%, 0.031%, 0.032%, 0.033%, 0.034%, 0.035%, 0.036%, 0.037%, 0.038%, 0.039%, 0.04%, 0.041%, 0.042%, 0.043%, 0.044%, 0.045%, 0.046%, 0.047%, 0.048%, 0.049%, 0.05%, etc.

[0055] The Sr elements with the above mass percentage can transform the eutectic Si from lamellar to fine granular, thereby improving the toughness of the aluminum alloy material.

[0056] The mass percentage of Ti element is 0.05%-0.30%, which includes but is not limited to the following point values and the range formed by any two point values: 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, etc.

[0057] In the embodiment of the present invention, by adding 0.05%-0.30% of Ti element to the aluminum alloy material, the Ti element acts as a heterogeneous nucleation site, thereby increasing the nucleation of primary (Al) grains, realizing grain refinement, and achieving the purpose of improving the strength and toughness of the aluminum alloy material.

[0058] RE is a rare earth element, which is selected from at least one of La and Ce. The mass percentage of RE element is 0.05%-0.2%, which includes but is not limited to the following point values and the range formed by any two point values: 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, etc.

[0059] In the embodiment of the present invention, by adding 0.05%-0.20% of RE element to the aluminum alloy material, the RE element acts as a heterogeneous nucleation site, thereby increasing the nucleation of primary (Al) grains, realizing grain refinement, and achieving the purpose of improving the strength and toughness of the aluminum alloy material.

[0060] The mass percentage of V element is 0.03%-0.05%, which includes but is not limited to the following point values and the range formed by any two point values: 0.0३%, 0.0३1%, 0.0३2%, 0.0३3%, 0.0३4%, 0.0३5%, 0.0३6%, 0.0३7%, 0.0३8%, 0.0३9%, 0.04%, 0.041%, 0.042%, 0.043%, 0.044%, 0.045%, 0.046%, 0.047%, 0.048%, 0.049%, 0.05%, etc.

[0061] The V element with the above mass percentage can refine eutectic silicon, form fine and dispersed phases, and at the same time can change the morphology of iron phases, thereby achieving the purpose of improving the strength and toughness of the aluminum alloy material.

[0062] In summary, the heat-treatment-free aluminum alloy material provided by the embodiments of the present invention selects specific types of various elements and combines them in specific mass percentages. The components work synergistically. On the one hand, this helps to reduce the liquidus temperature of the aluminum alloy material and improve the fluidity of the aluminum alloy melt, thereby ensuring the filling ability of the aluminum alloy material and being more conducive to forming using the one-piece die-casting process. On the other hand, this helps to improve the properties such as the strength, toughness, and deformation resistance of the aluminum alloy material.

[0063] Among them, the principle of improving the properties such as the strength, toughness, and deformation resistance of the aluminum alloy material in the embodiments of the present invention can be shown as follows:

[0064] During the solidification process of the aluminum alloy melt, elements such as Ca and Mg can form second phases such as AlCaSi phase, Al4Ca, Mg2Si, and Al-Si-Cu-Mg at the grain boundaries and refine the grains at the same time. The addition of V element and rare earth element RE makes there be more crystallization nuclei during the crystallization process of the aluminum alloy melt, the structure is finer, and at the same time, it also leads to the generation of more small granular second phases (such as Al2CaSi2). By strengthening the interaction between the phase and the dislocation, the movement of the dislocation is hindered, and the deformation resistance and mechanical strength of the alloy are significantly improved. In addition, elements such as Cu, Mg, and Si existing in the aluminum alloy matrix are more retained in the aluminum alloy matrix during the rapid cooling process. These strengthening elements will form strengthening phases in the aluminum alloy matrix during the subsequent aging heat treatment process, thereby improving the strength of the aluminum alloy matrix and achieving an aluminum alloy material with excellent comprehensive performance without additional solution heat treatment. In addition, a specific content of V element and rare earth element RE in the aluminum alloy material can form a near-spherical AlFeSiMnV phase with elements such as Al, Fe, Si, and Mn. This can not only effectively reduce the side effects brought by the harmful Fe phase in the aluminum alloy matrix, but also act as a strengthening phase to hinder the movement of dislocations, enabling the aluminum alloy to achieve the purpose of improving strength and toughness without heat treatment.

[0065] Regarding the above-mentioned heat-treatment-free aluminum alloy material, it is found that the mass ratio of elements such as Si and Ca will affect the change of the morphology and size of the AlCaSi phase, which directly affects the comprehensive performance of the aluminum alloy material.

[0066] In the embodiments of the present invention, the mass ratio of Si element to Ca element is expected to be 40 - 65:1, which includes but is not limited to: 40:1, 41:1, 42:1, 43:1, 44:1, 45:1, 46:1, 47:1, 48:1, 49:1, 50:1, 51:1, 52:1, 53:1, 54:1, 55:1, 56:1, 57:1, 58:1, 59:1, 60:1, 61:1, 62:1, 63:1, 64:1, 65:1, etc. This not only helps to improve the tensile strength, yield strength and elongation at break of the aluminum alloy material, but also helps to improve the fluidity of the aluminum alloy melt.

[0067] In some examples, in the embodiments of the present invention, the mass ratio of Si element to the total mass of Ca element, V element and RE element is expected to be 20 - 35:1, which includes but is not limited to: 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, etc. Thus, this not only helps to improve the tensile strength, yield strength and elongation at break of the aluminum alloy material, but also helps to improve the fluidity of the aluminum alloy melt.

[0068] In summary, the aluminum alloy provided by the embodiments of the present invention has both excellent strength and toughness, is suitable for high-vacuum integrated large die-castings of automobiles, and this aluminum alloy can be produced using recycled aluminum from automobiles, achieving a closed-loop production of automotive products and meeting the goal of low-carbon sustainable circular production.

[0069] On the other hand, the embodiments of the present invention also provide a preparation method of a heat-treatable aluminum alloy material, wherein, the heat-treatable aluminum alloy material is as described in any one of the above.

[0070] The preparation method of the heat-treatable aluminum alloy material includes the following steps:

[0071] Step 1: Provide preparation raw materials according to the mass percentages of each element in the heat-treatable aluminum alloy material.

[0072] Step 2: Perform melting treatment, slag skimming treatment and die-casting treatment on the preparation raw materials in sequence to prepare the heat-treatable aluminum alloy material.

[0073] Due to the adoption of the aluminum alloy material with the above volume in the embodiments of the present invention, it is possible to prepare an aluminum alloy material with excellent properties such as strength, toughness and deformation resistance without heat treatment during its preparation process.

[0074] In some examples, at least part of the raw materials in the preparation raw materials are selected from aluminum scrap, for example, the aluminum scrap is aluminum scrap recycled from automobiles.

[0075] By using aluminum scrap as a raw material for preparation, carbon emissions are greatly reduced, achieving low carbon and low cost, which is conducive to the low-carbon sustainable development of the industry.

[0076] In some examples, the aluminum scrap includes at least one of 1xxx series aluminum alloy scrap, 5xxx series aluminum alloy scrap, 6xxx series aluminum alloy scrap, A356 aluminum alloy scrap, A380 aluminum alloy scrap, AlSi7Mg0.3Cu0.5 aluminum alloy scrap, and AlSi9Cu3 aluminum alloy scrap. Among them, AlSi7Mg0.3Cu0.5 aluminum alloy scrap means that the mass percentages of Si element, Mg element, and Cu element in it are 7%, 0.3%, and 0.5% respectively. For example, 1xxx series aluminum alloy scrap usually includes aluminum wires, 5xxx series aluminum alloy scrap and 6xxx series aluminum alloy scrap usually include automotive body sheets, A356 aluminum alloy scrap usually includes wheels and hubs, A380 aluminum alloy scrap and AlSi9Cu3 aluminum alloy scrap usually include automotive suspension brackets, and AlSi7Mg0.3Cu0.5 aluminum alloy scrap usually includes automotive cylinder heads.

[0077] Automobiles have abundant aluminum alloy materials that can be recycled to obtain recycled aluminum. Moreover, compared with primary aluminum, the recycled aluminum process only requires 5% of the energy of primary aluminum, and the greenhouse gas emissions reach 95%. Of course, the cost is also significantly reduced.

[0078] When at least part of the raw materials in the preparation raw materials are selected from aluminum scrap, in order to ensure that each element in the aluminum alloy material is sufficiently provided and can be smoothly released into the aluminum alloy matrix through melting, the following elements in the preparation raw materials can be provided in specific forms respectively: Ca element is added in the form of Al-10Ca alloy (the mass percentage of Ca element in it is 10%); at least a part of the Si element is added in the form of Al-20Si alloy (the mass percentage of Si element in it is 20%); at least a part of the Mg element is added in the form of pure Mg; at least a part of the Mn element is added in the form of Al-20Mn alloy (the mass percentage of Mn element in it is 20%); at least a part of the Cu element is added in the form of Al-50Cu alloy (the mass percentage of Cu element in it is 50%); at least a part of the Zn element is added in the form of Al-20Zn alloy (the mass percentage of Zn element in it is 20%); at least a part of the V element is added in the form of Al-5V alloy (the mass percentage of V element in it is 5%); at least a part of the Ti element is added in the form of Al-10Ti alloy (the mass percentage of Ti element in it is 10%), and at least a part of the Sr element is added in the form of Al-10Sr alloy (the mass percentage of Sr element in it is 10%).

[0079] In some examples, the rare earth element RE is provided in the form of a mixture of La and Ce elemental substances.

[0080] In some examples, in step 1, according to the mass percentages of the elements in the heat-treatable aluminum alloy material, raw materials for preparation are provided, including:

[0081] Step 11: Classify, crush, and remove impurities from the aluminum scrap in sequence to obtain the aluminum scrap raw material, which is used as the raw material for the first part of the preparation.

[0082] Step 12: After determining the raw material for the first part of the preparation, determine and provide the raw material for the second part of the preparation according to the formula of the heat-treatable aluminum alloy material.

[0083] Step 13: According to the mass percentages of the elements in the heat-treatable aluminum alloy material, proportion the raw material for the first part of the preparation and the raw material for the second part of the preparation to obtain the raw material for preparation. Thus, it is ensured that a heat-treatable aluminum alloy material with a desired composition can be obtained after melting the raw material for preparation.

[0084] Furthermore, in step 2, the raw material for preparation is subjected to melting treatment, slag skimming treatment, and die-casting treatment in sequence to prepare the heat-treatable aluminum alloy material, including: subjecting the raw material for the first part of the preparation to melting treatment and dross removal treatment in sequence to obtain the first raw material melt; adding the components contained in the raw material for the second part of the preparation to the first raw material melt in a stepwise manner and performing melting treatment to obtain the aluminum alloy melt; performing die-casting treatment on the aluminum alloy melt to prepare the heat-treatable aluminum alloy material.

[0085] For example, at least one of waste aluminum wheels, waste suspension brackets, waste aluminum plates, and waste aluminum wires is used as the raw material for the first part of the preparation, and the raw material for the first part of the preparation is proportioned according to the formula of the heat-treatable aluminum alloy material. The proportioned raw material for the first part of the preparation is placed in a melting furnace for melting, and the melting temperature is set at 720°C - 740°C. After all the raw material for preparation is melted, the surface dross is removed, and then stirring is performed for 15 minutes - 20 minutes to obtain the first raw material melt.

[0086] Transfer the first raw material melt to a holding furnace at a temperature of 740°C - 750°C. Then, add the components contained in the second part of the preparation raw materials to the first raw material melt in a step-by-step manner and perform smelting treatment. For example, this can include: after the second part of the preparation raw materials is proportioned, add intermediate alloys of Al-20Si, Al-20Mn, and Al-50Cu with a specific ratio to the first raw material melt. After all these intermediate alloys are melted, start stirring for 5 - 8 minutes and hold for 15 - 20 minutes. Then, continue to heat up to 750°C - 760°C, add intermediate alloys of Al-10Ca, Al-5V, and Al-10Ti. After all these intermediate alloys are melted, stir for 5 - 8 minutes and hold for 15 - 20 minutes after stirring. Then, continue to add a sodium-free refining agent for refining for 10 - 15 minutes to reduce the temperature of the alloy liquid to 740°C - 750°C. Then, add the preheated Al-10Sr intermediate alloy and rare earth element RE, stir for 5 - 8 minutes, and introduce high-purity nitrogen gas to fully degas for a degassing time of greater than or equal to 20 minutes, thereby obtaining a pure aluminum alloy melt. Skim the scum from the aluminum alloy melt and let it stand for 20 - 25 minutes for later use.

[0087] In some examples, perform die-casting treatment on the aluminum alloy melt to prepare a heat-treatable aluminum alloy material, which can include: reducing the temperature of the aluminum alloy melt to 700°C - 710°C, and then performing die-casting forming treatment.

[0088] In summary, the preparation process of the heat-treatable aluminum alloy material provided by the embodiments of the present invention can obtain high strength and high toughness without heat treatment for the prepared heat-treatable aluminum alloy material. While reducing production costs, it can meet the requirements of die-casting forming of large automotive structural parts, and can replace the traditional die-cast aluminum alloy materials that require heat treatment in the automotive industry. Moreover, based on the use of aluminum scrap, the carbon reduction goal and cost reduction can also be achieved.

[0089] On the other hand, the embodiments of the present invention also provide an application of the heat-treatable aluminum alloy material in the preparation of aluminum alloy structural parts, wherein the heat-treatable aluminum alloy material is any one of the above, or is prepared by using any one of the preparation methods of the heat-treatable aluminum alloy materials involved above.

[0090] On the other hand, the embodiments of the present invention also provide an aluminum alloy structural part, which is prepared by using a heat-treatable aluminum alloy material, wherein the heat-treatable aluminum alloy material is any one of the above, or is prepared by using any one of the preparation methods of the heat-treatable aluminum alloy materials involved above.

[0091] Exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. For those techniques or conditions not specified in the examples, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For the reagents or instruments whose manufacturers are not indicated, they are all conventional products that can be obtained commercially.

[0092] Examples 1 - 8 and Comparative Examples 1 - 5 are provided in the embodiments of the present invention. Their formulations are shown in Table 1 below. Table 1 shows other elements except Al element and their mass percentages, and the Al element and its mass percentage are not shown in Table 1. The amount of Al element and inevitable impurities may constitute the remainder in the current embodiment. Among them, the RE element is a mixture of La simple substance and Ce simple substance, where the mass percentage of La simple substance is 35% and the mass percentage of Ce simple substance is 65%.

[0093] Table 1

[0094] Number Si Fe Cu Mn Mg Ti Zn Sr V Ca RE Example 1 7.5 0.29 0.6 0.42 0.40 0.15 0.149 0.031 0.04 0.15 0.15 Example 2 7.75 0.35 0.65 0.80 0.55 0.05 0.400 0.050 0.03 0.18 0.05 Example 3 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 0.19 0.16 Example 4 8.25 0.30 0.64 0.68 0.80 0.13 0.100 0.040 0.05 0.17 0.2 Example 5 8.3 0.40 0.60 0.50 0.75 0.18 0.301 0.015 0.041 0.18 0.15 Example 6 8.5 0.29 0.70 0.40 0.60 0.14 0.159 0.018 0.039 0.135 0.13 Example 7 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.05 0.19 0.2 Example 8 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.03 0.13 0.05 Comparative Example 1 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 / / Comparative Example 2 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 / 0.16 Comparative Example 3 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 0.19 / Comparative Example 4 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 0.12 0.13 Comparative Example 5 8.05 0.28 0.62 0.60 0.60 0.20 0.195 0.032 0.042 0.3 0.08

[0095] For the die-cast aluminum alloy structural parts prepared from the aluminum alloy materials shown in each of the examples and comparative examples shown in Table 1, the embodiments of the present invention also tested the tensile mechanical properties and bending angle of each die-cast aluminum alloy structural part, and also tested the fluidity of the aluminum alloy melt corresponding to each aluminum alloy material before die-casting. The test results are shown in Table 2.

[0096] Among them, the bending angle test can refer to the standard described in VDA238-100. The bending angle has a certain correlation with the toughness of the aluminum alloy material. Generally, the larger the bending angle, the better the toughness.

[0097] Regarding the fluidity test, after obtaining the aluminum alloy melt corresponding to the aluminum alloy material and before die-casting forming, the temperature of the aluminum alloy melt is reduced to 705°C, and then the cooled aluminum alloy melt is poured into a horizontally placed mold to allow it to flow freely. After cooling until the aluminum alloy melt solidifies and forms, measure the length of the obtained flow sample.

[0098] Table 2

[0099]

[0100]

[0101] As can be seen from Table 1 and Table 2, in Comparative Example 1, neither Ca element nor RE element was added; in Comparative Example 2, Ca element was not added; in Comparative Example 3, RE element was not added. Compared with Examples 1 - 6, it can be seen that when at least one of Ca element and RE element is not added to the aluminum alloy material, the strength, toughness, and fluidity of the aluminum alloy material all deteriorate.

[0102] In Comparative Example 4, the mass percentage of Ca element is 0.12%, not within the desired range of 0.13% - 0.19%, and the mass ratio of Si to Ca is 67:1, not within the range of 40 - 65:1. Compared with Example 3, the strength, toughness, and fluidity of the aluminum alloy material further deteriorate.

[0103] In Comparative Example 5, the mass percentage of Ca element is 0.3%, not within the desired range of 0.13% - 0.19%, and the mass ratio of Si to Ca is 27:1, not within the range of 40 - 65:1. Compared with Example 3, the strength, toughness, and fluidity of the aluminum alloy material further deteriorate.

[0104] In Examples 7 and 8, although the mass ratio of Si to Ca is within the range of 40 - 65:1, however, the mass ratio of Si to (Ca + V + RE) does not meet the range of 20 - 35:1. Compared with Example 3, the strength, toughness, and fluidity of the aluminum alloy material also show a deteriorating trend.

[0105] In addition, it was also found during the testing process that for the aluminum alloy materials provided in Examples 1 - 8, the castings do not stick to the mold during the die - casting process, and the fluidity test results are good. In addition, the present invention also made a microstructure analysis and a fracture scanning electron microscope analysis on the aluminum alloy die - castings corresponding to Example 3. The test results are respectively shown in Figures 1 - 3 .

[0106] Combined with the data in Table 2, it can be seen that the aluminum alloy die - castings corresponding to Example 3 have both high yield strength and high elongation (i.e., excellent toughness). From Figure 1 it can be seen that the matrix structure of the aluminum alloy die - castings corresponding to Example 3 is fine and uniform, and the modification effect is good. From Figures 2 - 3 it can be seen that the dimples on the fracture micro - morphology of the aluminum alloy die - castings corresponding to Example 3 are dense and uniform in size, and the toughness is good.

[0107] It can be seen that the aluminum alloy materials provided in the embodiments of the present invention, on the premise of ensuring excellent fluidity, also have excellent strength and toughness, achieving unexpected effects.

[0108] The term "and / or" in the embodiments of the present invention is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0109] The above description is only for the convenience of those skilled in the art to understand the technical solution of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aluminum alloy material without heat treatment, characterized in that The as-cast heat-treatable aluminum alloy material has the following elemental components by mass percentage: Si 7.5%-8.5%, Mg 0.4%-0.8%, Cu 0.6%-0.7%, Zn 0.1%-0.4%, Mn 0.4%-0.8%, Fe 0-0.4%, Ca 0.13%-0.25%, Sr 0.015%-0.050%, Ti 0.05%-0.30%, V 0.03%-0.05%, RE 0.05%-0.2%, inevitable impurities <0.03%, and Al as the balance, where the RE element is La and / or Ce; The mass ratio of the Si element to the total mass of the Ca element, V element, and RE element is 20-35:

1.

2. The heat-treatment-free aluminum alloy material according to claim 1, characterized in that The mass ratio of the Si element to the Ca element is 40-65:

1.

3. The heat-treatment-free aluminum alloy material according to any one of claims 1-2, characterized in that, The mass percentage of the Ca element is 0.15%-0.19%.

4. A preparation method of a heat-treatment-free aluminum alloy material, characterized in that, The as-cast heat-treatable aluminum alloy material is as described in any one of claims 1-3; The preparation method of the as-cast heat-treatable aluminum alloy material includes: providing preparation raw materials according to the mass percentages of the elements in the as-cast heat-treatable aluminum alloy material; Performing smelting treatment, slag skimming treatment, and die-casting treatment on the preparation raw materials in sequence to prepare the as-cast heat-treatable aluminum alloy material.

5. The preparation method of the heat-treatment-free aluminum alloy material according to claim 4, wherein, At least part of the preparation raw materials are selected from aluminum scrap.

6. The preparation method of the heat-treatment-free aluminum alloy material according to claim 5, wherein, The aluminum scrap includes at least one of 1xxx series aluminum alloy scrap, 5xxx series aluminum alloy scrap, 6xxx series aluminum alloy scrap, A356 aluminum alloy scrap, A380 aluminum alloy scrap, AlSi7Mg0.3Cu0.5 aluminum alloy scrap, and AlSi9Cu3 aluminum alloy scrap.

7. The preparation method of the heat-treatment-free aluminum alloy material according to claim 5, characterized in that, In the preparation raw materials, the Ca element is added in the form of Al-10Ca alloy; at least part of the Si element is added in the form of Al-20Si alloy; at least part of the Mg element is added in the form of pure Mg; at least part of the Mn element is added in the form of Al-20Mn alloy; at least part of the Cu element is added in the form of Al-50Cu alloy; at least part of the Zn element is added in the form of Al-20Zn alloy; at least part of the V element is added in the form of Al-5V alloy; at least part of the Ti element is added in the form of Al-10Ti alloy, and at least part of the Sr element is added in the form of Al-IO Sr alloy.

8. The preparation method of the heat-treatment-free aluminum alloy material according to claim 5, wherein The providing preparation raw materials according to the mass percentages of the elements in the as-cast heat-treatable aluminum alloy material includes: Classifying, crushing, and impurity removing the aluminum scrap in sequence to obtain aluminum scrap raw materials and use them as the first part of the preparation raw materials; After determining the first part of the preparation raw materials, determining and providing the second part of the preparation raw materials according to the formula of the as-cast heat-treatable aluminum alloy material; Performing batching on the first part of the preparation raw materials and the second part of the preparation raw materials according to the mass percentages of the elements in the as-cast heat-treatable aluminum alloy material to obtain the preparation raw materials.

9. The preparation method of the heat-treatment-free aluminum alloy material according to claim 8, characterized in that, The performing smelting treatment, slag skimming treatment, and die-casting treatment on the preparation raw materials in sequence to prepare the as-cast heat-treatable aluminum alloy material includes: The raw materials for preparing the first part are successively subjected to smelting treatment and dross removal treatment to obtain a first raw material melt; The components contained in the raw materials for preparing the second part are added to the first raw material melt in a step-by-step manner and subjected to smelting treatment to obtain an aluminum alloy melt; The aluminum alloy melt is subjected to die-casting treatment to prepare the heat-treatable aluminum alloy material.

10. Application of the heat-treatment-free aluminum alloy material in the preparation of aluminum alloy structural parts, characterized in that, The heat-treatable aluminum alloy material is as described in any one of claims 1-3, or is prepared by using the preparation method of the heat-treatable aluminum alloy material described in any one of claims 4-9.

11. An aluminum alloy structural member, characterized in that, The aluminum alloy structural member is prepared from a heat-treatable aluminum alloy material, and the heat-treatable aluminum alloy material is as described in any one of claims 1-3, or is prepared by using the preparation method of the heat-treatable aluminum alloy material described in any one of claims 4-9.

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