An aluminum alloy composite, its use and method of preparation and products comprising it

Abstract

This invention relates to an aluminum alloy composite material, its uses, preparation methods, and products comprising the same. Specifically, this invention relates to an aluminum alloy composite material for anodizing, comprising a core layer and at least one composite layer, wherein the composite layer comprises AA1XXX, AA5XXX, AA6XXX series alloys or combinations thereof; the core layer comprises Fe, Cu, Mn, Si, Mg, Zn, Zr, Ti, Cr, and Al, wherein, based on the total weight of the core layer, the total content of Fe, Cu, and Mn in the core layer is 0.6 to 3.3 wt%; and / or the total content of Zn, Zr, Ti, and Cr is 0.08 to 0.52 wt%. The aluminum alloy composite material of this invention exhibits good anodizing coloring effect and high strength. Furthermore, process waste and post-consumer waste can be used in the preparation process, reducing production costs.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy manufacturing technology, and in particular to a low-cost aluminum alloy composite material that can be used for anodizing, its uses and preparation methods, and products containing the same. Background Technology

[0002] With the rapid development of the computer, communication, and consumer electronics (3C) product industries, especially the widespread use of portable electronic devices such as laptops, mobile phones, and tablets, the market demand for lightweight, high-strength, and aesthetically pleasing metal materials is increasing. Aluminum alloys are widely used in the casings, frames, and internal structural components of electronic products due to their good machinability, low density, and the ability to achieve a wide range of colors through surface treatment.

[0003] Al-Mg-Si aluminum alloys, also known as 6XXX alloys, particularly 6063 and 6061, are the primary choice for casings in computer, communication, and consumer electronics products due to their high strength after artificial aging (i.e., in the T6 condition) and their uniform and bright anodized color. However, the production process for high-strength 6063 and 6061 aluminum alloys with excellent anodized color is complex and requires solution treatment in an air cushion furnace, resulting in high production and usage costs.

[0004] To reduce costs, Al-Mg alloys, also known as 5XXX alloys, have become the preferred material for many high-end 3C brands in recent years, replacing 6XXX alloys due to their excellent corrosion resistance and formability. However, to maintain uniform color after anodizing, the content of elements such as Si and Fe in 5XXX alloys needs to be strictly controlled. For example, the Si and Fe content in the currently mainstream 5252 aluminum alloy is less than 0.10% by weight, and even less than 0.05% by weight. This requires the use of high-purity aluminum (purity >99.90%) in the production of this 5252 aluminum alloy to meet its requirements for use in 3C product exterior parts. This also leads to an increase in production and usage costs.

[0005] To meet the technical requirements of high strength, lightweight, and thinning, CN119753383A and CN120210609A disclose a high-strength 5G50 aluminum alloy sheet and strip for anodizing and its preparation method. To improve material strength, a high Mg content (up to 4.6%) is added to this 5G50 aluminum alloy, along with a certain amount of Mn. However, when the Mg content in the aluminum alloy exceeds 3.5% by weight, Mg tends to segregate on the surface during annealing. This surface Mg enrichment severely affects the uniformity of anodizing corrosion, easily leading to discolored stripe defects, which negatively impacts the anodizing effect and consequently affects the color of 3C components.

[0006] Furthermore, most aluminum alloy scrap is currently downgraded and used to produce ordinary cast aluminum alloys. Better utilization of these process wastes and post-consumer wastes (such as the casings of discarded mobile phones, laptops, and tablets) as raw materials, achieving waste recycling, and ensuring the graded use of various wastes will be of great significance in reducing the use of pure aluminum ingots and lowering carbon emissions.

[0007] Therefore, it is particularly important to develop a new type of aluminum alloy material and its preparation process that is suitable for 3C products, especially one that can take into account low cost, low carbon content, good surface coloring effect and appropriate strength. Summary of the Invention

[0008] Currently, aluminum alloy materials used in 3C products struggle to simultaneously meet the requirements of low cost, low carbon footprint, good surface coloring effect, and high strength. To address these issues, this invention provides an aluminum alloy composite material with excellent anodizing effect and high strength. Furthermore, it allows for the incorporation of a large amount of aluminum alloy scrap during the preparation process, achieving a balance of low cost, high strength, and superior anodizing coloring effect, making it particularly suitable for 3C products.

[0009] In one aspect, the present invention relates to an aluminum alloy composite material comprising a core layer and at least one composite layer, wherein the composite layer comprises one or more alloys selected from the AA1XXX, AA5XXX, and AA6XXX series; the core layer comprises Fe, Cu, Mn, Si, Mg, Zn, Zr, Ti, Cr, and Al, wherein, based on the total weight of the core layer, the total content of Fe, Cu, and Mn in the core layer is 0.6 to 3.3 wt%; and / or the total content of Zn, Zr, Ti, and Cr is 0.08 to 0.52 wt%.

[0010] In one aspect, based on the total weight of the raw materials of the core layer of the present invention, the raw materials of the core layer contain more than 70% by weight of aluminum alloy scrap.

[0011] In another aspect, the present invention relates to an electronic product comprising the aluminum alloy composite material of the present invention.

[0012] In another aspect, the present invention relates to a method for preparing the aluminum alloy composite material of the present invention, comprising: preparing a core layer alloy and a composite layer alloy; heat-treating the core layer alloy and the composite layer alloy respectively; combining the core layer alloy and the composite layer alloy to obtain a composite; heat-treating the composite and rolling it to a target thickness; and annealing. Attached Figure Description

[0013] Figure 1a Photograph of the granular tissue in Example 1 of this invention.

[0014] Figure 1b Photograph of the grain structure of Example 1 of the present invention.

[0015] Figure 2a Photograph of the granular tissue in Example 14 of this invention.

[0016] Figure 2b Photograph of the grain structure of Example 14 of the present invention.

[0017] Figure 3a : Schematic diagram of the two-layer aluminum alloy composite material of the present invention.

[0018] Figure 3b : Schematic diagram of the three-layer aluminum alloy composite material of the present invention. Detailed Implementation

[0019] General definitions and terms

[0020] Unless otherwise stated, all publications, patent applications, patents and other references mentioned herein are incorporated herein in their entirety by way of citation.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of any conflict, the definitions provided herein shall prevail. Unless otherwise stated, all percentages, parts, proportions, etc., are by weight.

[0022] When a quantity, concentration, or other value or parameter is given as a range, preferred range, or preferred upper and lower limits, or a specific value, it should be understood as specifically disclosing all ranges formed by pairs of values ​​from any upper or preferred range and any lower or preferred range, regardless of whether the range is disclosed individually. Unless otherwise stated, when a numerical range is referred to herein, the range means including its endpoints and all integers and fractions within that range. The scope of this invention is not limited to the specific numerical value referenced when defining a range. For example, “1-8” or “1 to 8” encompasses 1, 2, 3, 4, 5, 6, 7, 8, and any subrange consisting of any two of these values, such as 2-6, 3-5.

[0023] When used with a numerical variable, the terms "about" or "approximately" usually mean that the value of the variable and all values ​​of the variable are within the experimental error (e.g., within a 95% confidence interval for the mean) or within ±10% of the specified value, or a wider range.

[0024] The terms “comprising,” “including,” “having,” “containing,” or “involving,” and their other variations herein, are inclusive or open-ended and do not exclude other unlisted elements or method steps. Those skilled in the art will understand that the foregoing terms such as “comprising” encompass the meaning of “consisting of.” The expression “consisting of” excludes any unspecified elements, steps, or ingredients. The expression “substantially constitutes” limits the scope to the specified elements, steps, or ingredients, plus optional elements, steps, or ingredients that do not materially affect the essential and novel features of the claimed subject matter. It should be understood that the expression “comprising” encompasses both the expressions “substantially constitutes” and “consisting of.”

[0025] The term “selected from…” means one or more elements from the groups listed below, selected independently, and may include combinations of two or more elements.

[0026] When describing numerical or range endpoints in this document, it should be understood that the disclosure includes the specific values ​​or endpoints referenced.

[0027] As used herein, the terms “one or more” or “at least one” refer to one, two, three, four, five, six, seven, eight, nine or more.

[0028] Unless otherwise stated, the terms "combination thereof" and "mixture thereof" refer to a multi-component mixture of the elements, such as two, three, four, and up to the maximum possible multi-component mixture.

[0029] Furthermore, if the number of components or parts of the present invention is not previously specified, it indicates that there is no limitation on the number of times a component or part may appear (or be present). Therefore, it should be interpreted as including one or at least one, and the singular form of a component or part also includes the plural, unless the value clearly indicates a singular number.

[0030] As used herein, the terms “optional” or “optionally” mean that the event or situation subsequently described may or may not occur, including both the occurrence and non-occurrence of the event or situation.

[0031] The term "solid solution" as used in this paper refers to an alloy phase in which solute atoms dissolve into the aluminum lattice while retaining their solvent-like properties. In this paper, solid solution mainly refers to a supersaturated aluminum solid solution formed when alloying elements such as Si, Cu, and Mn, due to rapid cooling during casting, do not have enough time to precipitate from the already solidified aluminum phase and are thus "solidified" within it. During subsequent thermomechanical processing, solute atoms such as Si, Cu, and Mn will precipitate from the supersaturated solid solution, forming dispersed particulate phases.

[0032] As used herein, the term "composite ratio" refers to the proportion of the thickness of each layer to the total thickness of the composite material. Taking the core layer as an example, the core layer composite ratio is the proportion of the core layer thickness to the total thickness of the composite material. For the composite material of this invention, the densities of each layer (core layer and composite layer) are almost identical; therefore, the composite ratio can also refer to the proportion of the weight of each layer to the total weight of the composite material. Taking the core layer as an example, the core layer composite ratio is the proportion of the core layer thickness to the total thickness of the composite material.

[0033] As used in this paper, the term "cubic texture" refers to a grain with a crystallographic orientation of {100}. <001> That is, the {100} crystal plane of the grain is parallel to the rolling plane of the plate, and the grain's <001> The crystal orientation is parallel to the rolling direction of the plate.

[0034] As used in this article, the term "texture percentage" refers to the percentage of the total area of ​​a certain type of texture, such as a cubic texture, relative to the total area of ​​the material. Texture percentage data can be obtained, for example, through electron backscatter diffraction (EBSD) testing.

[0035] As used herein, the terms "AA1XXX series alloys," "AA1XXX alloys," "1XXX series alloys," or "1XXX alloys" are common alloy designations well-known to those skilled in the art, such as in GB / T 3190-2016 Chemical Composition of Wrought Aluminum and Aluminum Alloys. AA1XXX series alloys are a series of alloys with an aluminum content greater than or equal to 99.00% by mass. The 1XXX series alloys in this document include, but are not limited to, AA1050 aluminum alloy.

[0036] As used herein, the terms "AA5XXX series alloys," "AA5XXX alloys," "5XXX series alloys," or "5XXX alloys" are commonly used alloy designations in the art, as well as those familiar with the art, such as those shown in GB / T 3190-2016 Chemical Composition of Wrought Aluminum and Aluminum Alloys. AA5XXX series alloys are a series of alloys with aluminum and magnesium as the main elements. The 5XXX alloys mentioned herein include, but are not limited to, AA5005 and AA5252 aluminum alloys.

[0037] As used herein, the terms "AA6XXX series alloys," "AA6XXX alloys," "6XXX series alloys," or "6XXX alloys" are commonly used alloy designations in the art, well-known to those skilled in the art, such as those shown in GB / T 3190-2016 Chemical Composition of Wrought Aluminum and Aluminum Alloys. AA6XXX series alloys are a series of alloys with aluminum, magnesium, and silicon as the main elements. AA6XXX series alloys in this document include, but are not limited to, AA6061 and AA6063 aluminum alloys.

[0038] As used in this document, the term "3C products" refers to computers, communication devices, and consumer electronics. Computer products include, but are not limited to, personal computers, laptops, and tablets; communication products include, but are not limited to, mobile phones and smartphones; and consumer electronics include, but are not limited to, digital cameras, MP3 players, and wearable devices.

[0039] Aluminum alloy composite materials

[0040] In one aspect, the present invention relates to an aluminum alloy composite material comprising a core layer and at least one composite layer.

[0041] When the composite layer is a single layer, the structure of the aluminum alloy composite material of the present invention is shown in Figure 3(a).

[0042] When the composite layer consists of two layers, the two composite layers are located on both sides of the core material layer, and its structure is shown in Figure 3(b).

[0043] The thickness of the aluminum alloy composite material of the present invention depends on the requirements of its actual application and is related to the number of layers, requiring adjustment based on the thickness of each layer. When the thickness is too small, it is not conducive to meeting the strength requirements of the composite material.

[0044] In one embodiment, the thickness of the aluminum alloy composite material of the present invention is 0.5 to 2.5 mm, preferably 0.7 to 2.3 mm, for example 0.5, 0.6, 0.7, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.25, 1.3, 1.35, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 mm, and a range consisting of any two of these values.

[0045] The aluminum alloy composite material of the present invention can be processed according to actual needs, including but not limited to plates and strips.

[0046] Composite layer

[0047] In the aluminum alloy composite material of the present invention, a composite layer covers the surface of the core layer. The composite layer primarily serves for anodizing and subsequent coloring. Therefore, the composite layer of the present invention should be suitable for anodizing and subsequent coloring.

[0048] Those skilled in the art will understand that Al, when used as an anode in an acidic electrolyte such as sulfuric acid, will undergo an oxidation reaction to form an Al2O3 oxide film. This Al2O3 oxide film has a porous structure, providing favorable conditions for subsequent coloring processes. These subsequent coloring processes can include dye coloring and electrolytic coloring. In dye coloring, a dye, such as an organic dye, is applied to the Al2O3 oxide film. The dye can then enter and adsorb into the pores of the Al2O3 oxide film, forming a relatively uniform coloring layer. In electrolytic coloring, the material with the Al2O3 oxide film is used as the cathode in the electrolytic reaction. Metal ions in the electrolyte, such as Sn... 2+ Ni 2+ Cu 2+ and Co 2+ At the cathode, a reduction reaction occurs, forming the corresponding metal or metal oxide. This metal or metal oxide is deposited at the bottom of the pores of the porous Al2O3 oxide film, and its color is revealed through optical interference.

[0049] To ensure good coloring results, the formed Al2O3 oxide film should be uniform, transparent, have regular pores, and be free from interference from impurity phases. Impurities in the aluminum alloy may affect these properties of the Al2O3 oxide film, thereby affecting the subsequent coloring effect.

[0050] In aluminum alloys, silicon (Si) exists as free Si particles or Al-Si eutectic during anodizing. During Al₂O₃ oxide film formation, the growth of the oxide film above the Si particles is hindered, easily forming cap-shaped or mushroom-shaped protrusions, while stress concentration cracks may appear around them. The resulting oxide film suffers from problems such as roughness, distorted channels, bifurcation, and decreased transparency. In subsequent dyeing, the reduced effective volume of the channels easily leads to low coloring intensity. In electrolytic dyeing, due to the strong insulation of the Si regions, current tends to bypass them, easily causing the deposited metal to form island-like distributions, resulting in a mottled color. Therefore, the Si content in the composite layer should be controlled.

[0051] In one embodiment, based on the total weight of the composite layer of the aluminum alloy composite material of the present invention, the Si content in the composite layer is less than 0.8% by weight, preferably less than 0.7% by weight, for example, 0.8, 0.79, 0.78, 0.77, 0.76, 0.75, 0.74, 0.73, 0.72, 0.71, 0.7, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.6, 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, 0.53, 0.52, 0.51, 0.5, 0.49, 0.48, 0.47 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.4, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01% by weight or less.

[0052] Fe in aluminum alloys exists as an intermetallic compound, Al3Fe. Al3Fe grows in needle-like shapes perpendicular to the surface. During oxide film formation, it anchors at the film / substrate interface, easily causing localized blistering or peeling of the oxide film. This leads to uneven coloring during subsequent coloring processes. Furthermore, the presence of Fe may cause the oxide film's base color to be light yellow to brownish-gray, interfering with subsequent coloring and severely reducing the purity of white or light-colored hues. Therefore, it is necessary to control the Fe content in the composite layer.

[0053] In one embodiment, based on the total weight of the composite layer of the aluminum alloy composite material of the present invention, the Fe content in the composite layer is less than 0.5% by weight, preferably less than 0.4% by weight, for example, 0.5, 0.49, 0.48, 0.47, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.4, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.3 2, 0.31, 0.3, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01% by weight or less.

[0054] In the composite layer, Cu reacts with Al to form the intermetallic compound Al₂Cu. During the initial stages of anodic oxidation, this compound undergoes a dealumination reaction, leaving Cu-rich microregions or voids. These Cu-rich microregions or voids can become conductive channels for electrons, leading to a sharp increase in local current density and consequently, problems such as localized overheating, film ablation, and pore collapse. If dyeing is subsequently used, the resulting defective Al₂O₃ oxide film can easily cause uneven dye adsorption, resulting in color spots and clouding. If electrolytic coloring is used later, the Cu in the composite layer may interfere with the reduction and deposition of metal ions in the cathode, leading to problems such as a reddish tint, dullness, and lack of luster in the color. Therefore, controlling the Cu content in the composite layer is essential.

[0055] In one embodiment, based on the total weight of the composite layer of the aluminum alloy composite material of the present invention, the content of Cu element in the composite layer is less than 0.3% by weight, preferably less than 0.25% by weight, for example, less than 0.3, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01% by weight.

[0056] In Zn-rich regions of aluminum alloys, Zn may rapidly precipitate during anodizing, leaving pits or pores. The oxide film cannot grow in these pits or pores, easily leading to problems such as localized thinning, tilted channels, branching, or even interruption of the film thickness. Al2O3 oxide films with these defects may result in light coloring, mottled patterns, or cloud-like textures during subsequent coloring processes. Therefore, it is necessary to control the Zn content in the composite layer.

[0057] In one embodiment, based on the total weight of the composite layer of the aluminum alloy composite material of the present invention, the content of Zn element in the composite layer is less than 0.06% by weight, preferably less than 0.05% by weight, for example less than 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01% by weight.

[0058] Some commercially available aluminum alloy materials can be used to meet the above requirements for composite alloys.

[0059] In one embodiment, the composite layer of the aluminum alloy composite material of the present invention comprises one or more alloys selected from the AA1XXX, AA5XXX, and AA6XXX series.

[0060] In one embodiment, the composite layer of the aluminum alloy composite material of the present invention comprises one or more alloys selected from AA1050, AA5005, AA5252, AA6061, and AA6063.

[0061] In the aluminum alloy composite material of this invention, the composite layers need to maintain a suitable composite ratio to ensure the overall properties of the composite material. If the composite ratio of the composite layers is too low, it may lead to poor anodizing coloring effect. If the composite ratio of the composite layers is too high, it may reduce the composite ratio of the core layer, resulting in a decrease in the mechanical properties of the composite material, such as yield strength and tensile strength, and increasing production costs. The composite ratio of the composite layers is also affected by the number of composite layers. Therefore, the composite ratio of the composite layers needs to be controlled within a suitable range.

[0062] In one embodiment, the composite ratio of the composite layer of the aluminum alloy composite material of the present invention is 5% to 30%, preferably 10% to 25%, for example 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, and a range consisting of any two of these values.

[0063] Core layer

[0064] On the one hand, in the aluminum alloy composite material of the present invention, the core layer does not perform the function of anodizing. Therefore, the core layer can contain relatively high impurities compared to the composite layer, without having too much impact on the overall performance of the aluminum alloy composite material.

[0065] On the other hand, the core layer is one of the main structures of aluminum alloy composites, and its properties (such as hardness, strength, and toughness) affect the performance of the composite material. Therefore, it is still necessary to control the content of each element in the core layer within an appropriate range.

[0066] In one embodiment, the core layer comprises Fe, Cu, Mn, Si, Mg, Zn, Zr, Ti, Cr, and Al.

[0067] In one embodiment, the total content of Fe, Cu and Mn is 0.6 to 3.3 by weight, based on the total weight of the core layer.

[0068] Fe in the core layer can combine with other elements, such as Mn and Si, to form casting crystalline phases. These crystalline phases can become intermetallic compounds with recrystallization nuclei, thus lowering the recrystallization temperature. Excessive Fe content may reduce the strength of the composite material. Therefore, it is necessary to control the Fe content in the core layer within an appropriate range.

[0069] In one embodiment, based on the total weight of the core layer, the Fe content in the core layer can be 0.3 to 0.7% by weight, preferably 0.3 to 0.6% by weight, for example, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.4 6, 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% by weight, and a range consisting of any two of these values.

[0070] Cu in the core layer has a solid solution strengthening effect. When the Cu content exceeds a certain level, the dissolved Cu will precipitate fine strengthening Al₂Cu particles at low temperatures, thus achieving a certain degree of age-strengthening. However, Cu tends to precipitate at grain boundaries, increasing the occurrence of intergranular corrosion. Therefore, it is necessary to control the Cu content in the core layer within an appropriate range.

[0071] In one embodiment, based on the total weight of the core layer, the Cu content in the core layer can be from 0.25 to 0.6% by weight, preferably from 0.25 to 0.55% by weight, for example, 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, 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% by weight, and a range consisting of any two of these values.

[0072] Including an appropriate amount of manganese (Mn) in the core layer helps improve the strength of the material. When the Mn content is too low, the advantages are not obvious; when the Mn content is too high, it will form large Mn-containing particles, which will affect the rolling process and lead to voids or broken strips in the material. Therefore, it is necessary to control the Mn content in the core layer within a suitable range.

[0073] In one embodiment, the Mn content in the core layer can be from 0.05 to 2% by weight, preferably from 0.2 to 1.3% by weight, for example, 0.05, 0.1, 0.2, 0.3, 0.4, 0.49, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, 1.0, 1.1, 1.14, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2% by weight, and a range consisting of any two of these values.

[0074] Si in the core layer has a significant impact on the properties of composite materials. In the core layer, Si, together with Fe and Mn, forms AlFeMnSi compounds, which play a role in dispersion strengthening. The fine, dispersed particles can control the recrystallization process and influence the size and orientation of the recrystallized grains. Si can react with Mg to form Mg₂Si compounds, thereby improving the strength of the composite material. Furthermore, Si can be dissolved in the core matrix, improving the material's strength through solid solution strengthening. Too low a Si content results in minimal technical benefits; too high a Si content significantly affects the composition and size of the dispersed phase particles, potentially weakening the strengthening effect and the impact on the grain structure.

[0075] In one embodiment, based on the total weight of the core layer, the Si content in the core layer can be from 0.2% to 1% by weight, preferably from 0.2% to 0.7% by weight, for example, 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, 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, 0.5 6, 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, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1% by weight, and a range consisting of any two of these values.

[0076] The magnesium (Mg) element in the core layer can significantly improve the strength of the alloy. On one hand, Mg can enhance strength through solid solution strengthening. On the other hand, the combination of Mg and Si will precipitate Mg₂Si nanoparticles, further increasing strength; the combination of Mg and Cu will precipitate AlCuMg nanoparticles, also improving strength. Furthermore, Mg and Cu can also form another type of Al₂CuMg reinforcing particles, thus exhibiting age-hardening capability.

[0077] In one embodiment, the Mg content in the core layer can be from 0.5 to 5.5% by weight, preferably from 0.8 to 5% by weight, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 0.93, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.38, 2.4, 2.5, 2.6, 2 7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.87, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.52, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5% by weight, and a range consisting of any two of these values.

[0078] In one embodiment, the total content of Zn, Zr, Ti and Cr in the core layer is 0.08 to 0.52 by weight, based on the total weight of the core layer.

[0079] The Zn content in the core layer affects the corrosion resistance of the material.

[0080] In one embodiment, the Zn content in the core layer can be from 0.03 to 0.3% by weight, preferably from 0.02 to 0.2% by weight, for example, 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% by weight, and a range consisting of any two of these values.

[0081] Adding Zr to the core layer can control the size of recrystallized grains. However, when the Zr content is too high, large intermetallic compounds are easily formed, reducing the alloy's workability. Therefore, the Zr content in the core layer must be controlled within a suitable range.

[0082] In one embodiment, the Zr content in the core layer can be from 0.01 to 0.06% by weight, preferably from 0.01 to 0.05% by weight, for example, 0.01, 0.011, 0.012, 0.013, 0.014, 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, 0.051, 0.052, 0.053, 0.054, 0.055, 0.056, 0.057, 0.058, 0.059, 0.06% by weight, and a range consisting of any two of these values.

[0083] Ti in the core layer enhances its strength and corrosion resistance through solid solution strengthening. However, excessive Ti content can lead to the formation of large intermetallic compounds, reducing the alloy's workability. Therefore, the Ti content in the core layer must be controlled within a suitable range.

[0084] In one embodiment, the Ti content in the core layer is 0.03 to 0.1 wt%, preferably 0.03 to 0.09 wt%, for example 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 wt%, and a range consisting of any two of these values.

[0085] Cr can form intermetallic compounds such as AlCrFe and AlMnCr in Al-containing alloys, hindering the nucleation and growth processes of recrystallization, but increasing quenching sensitivity. Therefore, it is necessary to control the Cr content in the core layer within a suitable range.

[0086] In one embodiment, the Cr content in the core layer is 0.01 to 0.06 wt%, preferably 0.01 to 0.05 wt%, for example 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 wt%, and a range consisting of any two of these values.

[0087] Grain size

[0088] In this invention, the grain size of the core layer affects its performance. Plastic deformation in alloys primarily occurs through dislocation slip. Under external force, dislocations move along the slip plane, causing crystal shear. However, in polycrystalline materials, adjacent grains have different orientations, resulting in discontinuous slip systems. Therefore, the deformation of a single grain must be coordinated with that of neighboring grains. When a dislocation slips within a grain, it is blocked by grain boundaries. Subsequent dislocations continue to be generated and advance, but because they cannot cross the grain boundaries, they accumulate in front of the boundaries, forming pile-up clusters. These pile-up dislocations repel each other, creating a stress concentration that acts on the in front grain boundary and adjacent grains. Therefore, grain boundaries can suppress the generation of continuous slip. Refining the grains increases the area of ​​the grain boundaries, thereby enhancing the material's ability to suppress continuous slip and thus inhibit plastic deformation, improving the material's strength.

[0089] In addition to improving material strength, refining grains can also improve fracture toughness, fatigue performance, and promote uniform forming of materials.

[0090] However, when the grain size is too small, for example, less than 10 to 100 nm, the deformation mechanism of the alloy changes from dislocation slip to grain boundary slip or grain boundary diffusion. Further reducing the grain size will produce the reverse Hall-Petch effect, leading to a decrease in material strength. Therefore, it is necessary to control the grain size of the core layer within a suitable range.

[0091] Grain size can be measured using conventional equipment in the art, such as an optical microscope. Exemplary operating steps are described in the Examples section below.

[0092] In one embodiment, the grain size of the core layer of the aluminum alloy material of the present invention is 10 to 60 μm, preferably 20 to 50 μm, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 μm, and a range consisting of any two of these values.

[0093] Texture

[0094] Texture refers to the phenomenon where randomly oriented grains within a polycrystalline material align in a regular pattern along a specific direction. The distribution of texture can influence the mechanical properties of an alloy, such as strength, plasticity, and toughness, as well as its physical properties, such as electrical conductivity and magnetism. Therefore, texture distribution is a crucial microscopic parameter determining the properties of alloy materials.

[0095] The distribution of texture can be measured, for example, by field emission electron microscopy, with exemplary operating methods described in the Examples section below.

[0096] In one embodiment, the core layer of the aluminum alloy material of the present invention comprises a cubic texture.

[0097] In one embodiment, the area of ​​the cubic texture of the core layer of the aluminum alloy material of the present invention accounts for 8 to 14% of the total area of ​​the material, preferably 8.5 to 13%, for example 8, 8.5, 8.9, 9, 9.1, 9.3, 9.5, 10, 10.1, 10.2, 10.3, 10.5, 10.7, 11, 11.1, 11.4, 11.5, 11.8, 11.9, 12, 12.1, 12.2, 12.3, 12.5, 13, 13.5, 14%, and a range consisting of any two of these values.

[0098] Raw materials for the core layer

[0099] The raw materials for the core layer refer to the materials used to prepare the core layer. The raw materials for the core layer can be alloy ingots formed by melting various materials. The raw materials used to manufacture the core layer of this invention can contain a relatively high content of impurities without significantly affecting the performance of the aluminum alloy composite material of this invention. Therefore, aluminum alloy scrap can be used as the raw material for the core layer of this invention. The core layer is the main part of the composite material, that is, the weight of the core layer accounts for a high proportion of the total weight of the composite material. Therefore, including a certain proportion of aluminum alloy scrap in the raw materials of the core layer can significantly improve the recycling efficiency of waste materials, which is of great significance to environmental protection goals.

[0100] Aluminum alloy scrap is typically a recycled material. Therefore, compared to non-recycled alloy materials (such as commercially available aluminum alloys), the elemental composition of aluminum alloy scrap is usually more complex, often containing higher levels of elements such as Si and Mn. However, for aluminum alloy materials used in anodizing, the impurity content, such as Si and Mn, needs to be controlled within appropriate ranges; otherwise, it will affect the anodizing and coloring effects. In this invention, by using a multi-layer structure instead of the traditional single-layer material and optimizing the composition and proportion of each layer in the composite material, an anodizing aluminum alloy composite material with good anodizing effect and high mechanical strength can be obtained. Therefore, this invention, while using a significant amount of aluminum alloy scrap as raw material for each layer, can still ensure that the resulting composite material has excellent performance.

[0101] The aluminum alloy scrap suitable for preparing the core material layer of this invention can be process waste, post-consumer waste, or a combination of both. Process waste refers to the waste that is inevitably generated during the production and processing process due to limited yield; this part of the waste is called process waste. Post-consumer waste refers to the waste generated as products containing aluminum alloy materials (such as computers and mobile phones) are scrapped; this part of the waste is called post-consumer waste.

[0102] In one embodiment, the process waste is the waste generated during the preparation of the aluminum alloy composite material of the present invention.

[0103] In one implementation scheme, post-consumer waste refers to waste from 3C products.

[0104] When aluminum alloy scrap contains high levels of Si and Mn or has a complex composition of elements, its reuse becomes more difficult. The composite material designed using this invention can maintain material performance while consuming a significant amount of waste during its preparation.

[0105] In one embodiment, based on the total weight of the raw materials of the core layer, the raw materials of the core layer contain more than 70% by weight of aluminum alloy scrap, for example, containing 70 to 98% by weight of aluminum alloy scrap, for example, containing 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98% by weight of aluminum alloy scrap, and a range consisting of any two of these values.

[0106] In one implementation, based on the total weight of the raw materials of the core layer, the raw materials of the core layer contain more than 20% by weight of process waste, for example, 20 to 55% by weight of process waste, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55% by weight of process waste, and a range consisting of any two of these values.

[0107] The types and contents of elements contained in process waste can be calculated using the raw materials used in the production process and their relative contents. Specifically, the composition of process waste = core layer composition × core layer composite rate % + composite layer composition × composite layer composite rate %.

[0108] In one embodiment, the Si content in the process waste available in this invention is 0.3 to 0.9% by weight, preferably 0.35 to 0.85% by weight, for example, 0.3, 0.35, 0.4, 0.44, 0.45, 0.49, 0.5, 0.51, 0.54, 0.55, 0.59, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.7, 0.72, 0.73, 0.74, 0.75, 0.77, 0.8, 0.85, 0.9% by weight, and a range consisting of any two of these values.

[0109] In one embodiment, the Fe content in the process waste available in this invention is 0.2 to 0.8% by weight, preferably 0.2 to 0.7% by weight, for example, 0.2, 0.25, 0.29, 0.3, 0.31, 0.35, 0.36, 0.37, 0.38, 0.4, 0.41, 0.44, 0.45, 0.5, 0.54, 0.55, 0.56, 0.6, 0.65, 0.7, 0.75, 0.8% by weight, and a range consisting of any two of these values.

[0110] In one embodiment, the Cu content in the process waste available in this invention is 0.1 to 0.6% by weight, preferably 0.15 to 0.50% by weight, for example, 0.1, 0.15, 0.2, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.33, 0.34, 0.35, 0.4, 0.41, 0.43, 0.44, 0.45, 0.5, 0.55, 0.6% by weight, and a range consisting of any two of these values.

[0111] In one embodiment, the Mn content in the process waste available in this invention is from 0.01 to 1.3% by weight, preferably from 0.015 to 1.2% by weight, for example, 0.01, 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.31, 0.33, 0.35, 0.36, 0.37, 0.39, 0.4, 0.42, 0.43, 0.45, 0.46, 0.5, 0.55, 0.6, 0.65, 0.7, 0.72, 0.73, 0.77, 0.8, 0.85, 0.9, 0.95, 1, 1.01, 1.03, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3% by weight, and a range consisting of any two of these values.

[0112] In one embodiment, the Mg content in the process waste available in this invention is 0.6 to 6 wt%, preferably 0.7 to 5 wt%, for example, 0.6, 0.84, 0.91, 0.92, 0.93, 1, 1.05, 1.1, 1.5, 1.87, 2, 2.13, 2.14, 2.17, 2.5, 3, 3.18, 3.23, 3.43, 3.44, 3.49, 3.5, 3.68, 3.75, 3.88, 4, 4.06, 4.07, 4.21, 4.31, 4.5, 5, 5.5, 6 wt%, and a range consisting of any two of these values.

[0113] In one embodiment, the Zn content in the process waste available in this invention is 0.01 to 0.25% by weight, preferably 0.02 to 0.2% by weight, for example, 0.01, 0.03, 0.04, 0.05, 0.06, 0.08, 0.09, 0.10, 0.11, 0.12, 0.15, 0.16, 0.20, 0.21, 0.25% by weight, and a range consisting of any two of these values.

[0114] In one embodiment, the Zr content in the process waste available in this invention is 0.01 to 0.06 wt%, preferably 0.01 to 0.05 wt%, for example 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 wt%, and a range consisting of any two of these values.

[0115] In one embodiment, the Ti content in the process waste available in this invention is 0.01 to 0.1 wt%, preferably 0.02 to 0.1 wt%, for example 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 wt%, and a range consisting of any two of these values.

[0116] In one embodiment, the Cr content in the process waste available in this invention is 0.01 to 0.06 wt%, preferably 0.01 to 0.05 wt%, for example 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 wt%, and a range consisting of any two of these values.

[0117] In one implementation, based on the total weight of the raw materials of the core layer, the raw materials of the core layer contain more than 30% by weight of post-consumer waste, for example, containing 30 to 70% by weight of post-consumer waste, for example, containing 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70% by weight of post-consumer waste, and a range consisting of any two of these values.

[0118] The types and amounts of elements contained in post-consumer waste depend on the source and type of post-consumer waste.

[0119] In one embodiment, the Si content in the post-consumer waste available in this invention is 0.1 to 0.5 wt%, preferably 0.1 to 0.4 wt%, for example 0.1, 0.15, 0.2, 0.25, 0.28, 0.3, 0.35, 0.4, 0.45, 0.5 wt%, and a range consisting of any two of these values.

[0120] In one embodiment, the Fe content in the post-consumer waste available in this invention is 0.1 to 0.7 wt%, preferably 0.1 to 0.6 wt%, for example 0.1, 0.15, 0.2, 0.25, 0.26, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7 wt%, and a range consisting of any two of these values.

[0121] In one embodiment, the Cu content in the post-consumer waste available in this invention is 0.02 to 0.3% by weight, preferably 0.03 to 0.25% by weight, for example 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3% by weight, and a range consisting of any two of these values.

[0122] In one embodiment, the Mn content in the post-consumer waste available in this invention is 0.05 to 2% by weight, preferably 0.1 to 1.5% by weight, for example, 0.05, 0.1, 0.15, 0.2, 0.23, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.12, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2% by weight, and a range consisting of any two of these values.

[0123] In one embodiment, the Mg content in the post-consumer waste available in this invention is 0.3 to 3.5 wt%, preferably 0.4 to 3 wt%, for example 0.3, 0.5, 0.55, 1.0, 1.5, 2.0, 2.5, 2.73, 3.0, 3.5 wt%, and a range consisting of any two of these values.

[0124] In one embodiment, the Zn content in the post-consumer waste available in this invention is 0.02 to 0.2% by weight, preferably 0.03 to 0.15% by weight, for example 0.03, 0.05, 0.1, 0.15, 0.2% by weight, and a range consisting of any two of these values.

[0125] In one embodiment, the Zr content in the post-consumer waste available in this invention is 0.005 to 0.03% by weight, preferably 0.005 to 0.02% by weight, for example 0.005, 0.01, 0.015, 0.02, 0.025, 0.03% by weight, and a range consisting of any two of these values.

[0126] In one embodiment, the Ti content in the post-consumer waste available in this invention is 0.01 to 0.06 wt%, preferably 0.02 to 0.05 wt%, for example 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.06 wt%, and a range consisting of any two of these values.

[0127] In one embodiment, the Cr content in the post-consumer waste available in this invention is 0.005 to 0.4 wt%, preferably 0.005 to 0.3 wt%, for example 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4 wt%, and a range consisting of any two of these values.

[0128] In one embodiment, the post-consumer waste available under this invention comprises 3XXX and / or 5XXX alloys, such as AA3003, AA3004, AA5052, and AA5754 alloys.

[0129] In one embodiment, the post-consumer waste added during the preparation process can be waste generated after the electronic products containing the aluminum alloy composite material for anodizing of the present invention are scrapped.

[0130] Mechanical properties

[0131] The physical strength of alloy materials can be measured by tensile testing. Tensile testing can be performed in a manner commonly used in the art, for example, according to the EN10002-1 standard. Exemplary operating procedures are described in the Examples section below.

[0132] The Rp0.2 value of an alloy material can be measured through tensile testing. This value represents the stress corresponding to 0.2% irreversible plastic deformation during tensile testing. This value reflects the yield strength of the alloy material. The aluminum alloy composite material of this invention exhibits good Rp0.2 yield strength.

[0133] In one embodiment, the yield strength Rp0.2 of the aluminum alloy composite material of the present invention is 180 to 400 MPa, preferably 185 to 350 MPa, for example, 180, 185, 190, 191, 195, 199, 200, 201, 203, 205, 207, 208, 210, 211, 213, 215, 220, 225, 229, 230, 231, 233, 235, 238, 240, 245, 250, 255, 260, 262. 265, 270, 275, 280, 285, 290, 291, 295, 296, 298, 300, 302, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, 400 MPa, and a range consisting of any two of these values.

[0134] Tensile testing can also measure the Rm (also known as tensile strength) of the alloy material, which represents the maximum stress the material can withstand before fracture. The aluminum alloy composite material of this invention has good tensile strength.

[0135] In one embodiment, the tensile strength Rm of the aluminum alloy composite material of the present invention is 200 to 450 MPa, preferably 235 to 400 MPa, for example, 200, 205, 210, 215, 220, 225, 230, 235, 240, 241, 245, 246, 247, 250, 251, 253, 255, 260, 261, 265, 270, 275, 280, 285, 290, 295, 299, 300, 302, 303, 305, 307. 310, 315, 320, 325, 330, 335, 340, 343, 345, 350, 354, 355, 360, 361, 363, 365, 370, 371, 375, 380, 385, 390, 395, 400, 405, 410, 415, 420, 425, 430, 435, 440, 445, 450 MPa, and the range formed by any two of these values.

[0136] Anodizing effect

[0137] The anodizing coloring effect of aluminum alloys can be tested by conventional methods in the art, for example, according to GB / T12967.6-2022 Test Methods for Anodized Films of Aluminum and Aluminum Alloys Part 6: Visual Inspection Method for Color Difference and Appearance Quality of Colored Anodized Films. Exemplary operating steps are shown in the Examples section below.

[0138] The aluminum alloy composite material of the present invention has excellent anodizing coloring effect, and its color is uniform and the color difference ΔE is small after coloring.

[0139] In one embodiment, the color difference ΔE of the anodic oxide film of the aluminum alloy composite material of the present invention, as evaluated according to GB / T12967.6-2022, is less than 1.0, preferably less than 0.9, for example, 1.0, 0.95, 0.9, 0.87, 0.85, 0.84, 0.8, 0.78, 0.77, 0.76, 0.75, 0.73, 0.72, 0.71, 0.7, 0.69, 0.67, 0.65, 0.63, 0.62, 0.61, 0.6, 0.59, 0.55, 0.52, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, and a range consisting of any two of these values.

[0140] Preparation of aluminum alloy composite materials

[0141] In another aspect, the present invention relates to a method for preparing aluminum alloy composite materials, comprising the following steps: Preparation of core layer alloys and composite layer alloys; The core layer alloy and the composite layer alloy are heat-treated separately. A composite material is obtained by combining a core layer alloy and a composite layer alloy. The composite is heat-treated and then rolled to the target thickness; annealing.

[0142] By selecting suitable raw materials, a core layer and composite layer with the composition described above are obtained through melting and casting. The inventors discovered that by controlling the composition (e.g., the types and amounts of elements included) and microstructure (e.g., grain size and texture distribution) of the core layer and composite layer, and by rationally designing the structure of the composite material (e.g., using the multi-layer structure described above), a certain proportion of waste material can be added during the preparation of the core layer alloy, thereby achieving the goal of green environmental protection. Simultaneously, it ensures that the resulting composite material possesses good performance (e.g., high mechanical strength with good anodizing coloring effect). This solves the problem that traditional anodizing aluminum alloy materials cannot simultaneously achieve low cost, good anodizing, and high mechanical strength.

[0143] Therefore, in one embodiment, the step of preparing the core layer alloy includes adding aluminum alloy scrap.

[0144] In the preparation process of this invention, the added aluminum alloy scrap can be: process waste, post-consumer waste, or a combination thereof. "Aluminum alloy scrap," "process waste," and "post-consumer waste" are as described above.

[0145] The inventors discovered that the composite material obtained through the design of this invention can have all its process waste (i.e., waste generated during the preparation of the composite material of this invention) and post-consumer waste (i.e., waste generated after products using the composite material of this invention, such as computers and mobile phones, are scrapped) completely recycled, without generating additional unusable waste. The process waste and post-consumer waste of the composite material of this invention can be reused to prepare the core layer in the composite material of this invention. That is, the aluminum alloy composite material for anodizing of this invention can achieve material self-circulation.

[0146] In one embodiment, the process waste added during the preparation process can be waste generated during the preparation of the aluminum alloy composite material for anodizing of the present invention.

[0147] In one embodiment, the post-consumer waste added during the preparation process can be waste generated after a product comprising the aluminum alloy composite material for anodizing of the present invention is scrapped.

[0148] In one embodiment, the post-consumer waste added during the preparation process can be waste generated after the electronic products containing the aluminum alloy composite material for anodizing of the present invention are scrapped.

[0149] By employing appropriate heat treatment, a desired microstructure can be formed in the core layer alloy, resulting in uniformly sized, small particles, and the density of dispersed phase particles <0.3 μm can be controlled. Excessive heat treatment temperature leads to particle coarsening; insufficient heat treatment temperature makes particle precipitation difficult, both of which are detrimental to achieving the desired density of dispersed phase particles <0.3 μm.

[0150] In one embodiment, the heat treatment temperature of the core layer alloy is 480 to 580°C, preferably 500 to 560°C, for example 480, 485, 490, 495, 500, 505, 510, 515, 520, 525, 530, 535, 540, 545, 550, 555, 560, 565, 570, 575, 580°C, and a range consisting of any two of these values.

[0151] In one embodiment, the heat treatment time for the core layer alloy is 8 to 15 hours, for example, 8, 9, 10, 11, 12, 13, 14, 15 hours, and a range consisting of any two of these values.

[0152] By employing appropriate heat treatment, a desired microstructure can be formed in the composite alloy, resulting in uniformly sized, small particles, and the density of dispersed particle phases <0.3 μm can be controlled. Excessive heat treatment temperature leads to particle coarsening; insufficient heat treatment temperature makes particle precipitation difficult, both of which are detrimental to achieving the desired density of dispersed particle phases <0.3 μm.

[0153] In one embodiment, the heat treatment temperature of the composite alloy is 450 to 550°C, preferably 470 to 530°C, for example 450, 455, 460, 465, 470, 475, 480, 485, 490, 495, 500, 505, 510, 515, 520, 525, 530, 535, 540, 545, 550°C, and a range consisting of any two of these values.

[0154] In one embodiment, the heat treatment time for the composite alloy is 8 to 15 hours, for example, 8, 9, 10, 11, 12, 13, 14, 15 hours, and a range consisting of any two of these values.

[0155] The alloy layers can be processed using relevant techniques (such as head cutting and milling).

[0156] The core layer alloy and / or composite layer alloy can be rolled to a suitable thickness by hot rolling.

[0157] In one embodiment, the composite alloy is hot-rolled.

[0158] The plate-shaped core material layer alloy and the composite layer alloy are stacked sequentially and then bonded together to obtain a composite. Those skilled in the art will understand that the stacking order can be designed according to the desired composite material. The relative positional relationships of the alloys in the composite are the same as those in the final composite material.

[0159] The composite is rolled to the target thickness. Rolling methods may include hot rolling, cold rolling, and combinations thereof.

[0160] In one embodiment, rolling includes hot rolling and cold rolling. The thickness after hot rolling can be determined based on the desired final product thickness and subsequent processing. In a further embodiment, the thickness of the hot-rolled composite is 3 to 10 mm.

[0161] In one embodiment, cold rolling includes two or more cold rolling processes, and annealing may be performed after cold rolling. In a further embodiment, cold rolling includes a first cold rolling, annealing after the first cold rolling, a second cold rolling, and annealing after the second cold rolling. The annealing temperature after the first cold rolling is 300 to 380 °C, and the annealing time is 1 to 10 hours, preferably 2 to 6 hours; the annealing temperature after the second cold rolling is 100 to 250 °C, and the annealing time is 1 to 10 hours, preferably 2 to 6 hours.

[0162] The preparation method of this invention can endow composite materials with desired structures (such as multilayer structures, micro-particle states, etc.) and material properties. The obtained composite materials have good anodizing coloring effects, high mechanical strength, and can also consume less waste, achieving the goals of low carbon emissions and cost control. They are particularly suitable for manufacturing various components of various electronic products, such as shells, mid-frames, and internal components, and are especially suitable for various components in electronic products that require both appearance color and structural strength.

[0163] Beneficial effects

[0164] Currently, the production cost of aluminum alloy materials with good anodizing coloring effect and high strength is relatively high. Attempts to reduce costs inevitably affect the anodizing effect and / or strength of the materials, making it difficult to achieve an ideal balance among the three.

[0165] In addition, the current recycling rate of aluminum alloy scrap is not high, and most aluminum alloy scrap on the market is directly downgraded for use.

[0166] The aluminum alloy composite material for anodizing of the present invention overcomes the aforementioned problems. Specifically, the aluminum alloy composite material of the present invention uses a multi-layer structure instead of the single-layer structure of traditional aluminum alloy materials for anodizing, optimizes the composition and proportion of each layer, and controls the microstructure of each layer, thereby obtaining a material with good anodizing coloring effect and high mechanical strength. Simultaneously, the core layer of the aluminum alloy composite material of the present invention can contain a higher amount of impurities than the composite layers without significantly affecting the overall performance of the composite material. Therefore, in the preparation of the composite material of the present invention, a large amount of aluminum alloy waste can be used for the core layer, and the process waste and post-consumer waste generated during the preparation process can be fully recycled without generating additional unusable waste, achieving material self-circulation. This can significantly reduce carbon emissions and control production costs. The aluminum alloy composite material of the present invention combines low cost, good anodizing coloring effect, and high strength, making it an ideal and economical material suitable for manufacturing various components in electronic products that require both appearance color and structural strength.

[0167] Example

[0168] The present invention will now be described in further detail with reference to specific embodiments.

[0169] It should be noted that the following embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here, and obvious variations or modifications derived therefrom are still within the protection scope of this invention. Unless otherwise specified, the instruments, equipment, and reagents used herein are commercially available.

[0170] Sample preparation

[0171] Samples of the embodiments and comparative examples of the present invention were prepared according to the following method: The core material layer alloy and the composite layer alloy with specific composition are smelted and cast respectively, and a certain amount of waste is added during the preparation of the core material layer alloy. The core material layer alloy was heat-treated at 545℃ for 12 hours, followed by head cutting and milling. The composite alloy was heat-treated at 500°C for 12 hours, then cut off the head, milled the surface, and hot-rolled to the required thickness. The core layer and composite layer are preheated at 480°C and then hot-rolled together by a hot rolling mill to produce aluminum alloy composite materials with a thickness of 3 to 10 mm. The composite material is cold-rolled to a thickness of 1.5 to 2.5 mm and then annealed at a temperature of 300 to 380 ℃ for 2 to 6 h to obtain an annealed coil. After cooling the annealed coil, it is cold rolled to the finished thickness shown in Table 2 below to obtain the cold rolled coil. The cold-rolled coils are then subjected to final annealing at a temperature of 100 to 250°C for 2 to 6 hours.

[0172] The structures, components of each layer, composite ratios, and thicknesses of the embodiments and comparative examples are shown in Tables 1 and 2 below.

[0173] Table 1

[0174] Table 2

[0175] Process waste production rate This refers to the proportion of waste material produced during the preparation of composite materials to the total weight of raw materials.

[0176] The composition of the generated process waste was calculated using the following formula, and the results are shown in Table 3 below: Process waste composition = Core layer composition × Core layer composite rate % + Composite layer composition × Composite layer composite rate.

[0177] Taking Si as an example, the Si content in process waste = Si content in the core layer × core layer composite rate % + Si content in the composite layer × composite layer composite rate.

[0178] Table 3

[0179] Post-consumer waste is classified according to alloy series, and its typical composition is shown in Table 4 below.

[0180] Table 4

[0181] Table 5 shows the waste consumption of each embodiment and comparative example. The waste consumption rate in Table 5 represents the proportion of the weight of waste added during the preparation of the core layer to the weight of the core layer. The post-consumption waste consumption rate refers to the proportion of the weight of post-consumption waste added during the preparation of the core layer to the weight of the core layer. The self-generated process waste consumption rate refers to the proportion of the weight of process waste added during the preparation of the composite material's core material to the weight of the core layer, where the added process waste refers to waste generated during the process of preparing the composite material itself.

[0182] Taking Example 1 in Table 5 as an example, the alloy of its core layer is alloy X1. During the preparation of the composite material of Example 1, the yield of process waste (code S110) was 30%. All the generated process waste S110 was added to the preparation of alloy X1, along with a certain proportion of post-consumer waste (mainly post-consumer waste from aluminum alloys used in 3C product components) and other alloy raw materials. The resulting alloy X1 can be used as the core layer alloy of the composite material of Example 1. The total waste consumption rate is the sum of the process waste consumption rate and the post-consumer waste consumption rate.

[0183] As can be seen from the data in Table 5, the total waste consumption rate in the examples is relatively high, all above 80%.

[0184] Table 5

[0185] Waste consumption rate The proportion of the weight of waste material added during the preparation of the core layer to the total weight of the core layer.

[0186] Grain size measurement

[0187] The prepared sample plates were cut into 20 mm × 20 mm pieces and hot-mounted, with the rolling direction of the sample serving as the observation surface. The samples were then subjected to rough grinding, fine grinding, polishing, and final polishing to prepare the required metallographic specimens. The prepared metallographic specimens were then coated using a DC power supply coating machine, with the observation surface immersed in the coating solution. The voltage was controlled at 30 V, and the coating time was 100 s. After coating, the specimens were cleaned with water and then with alcohol. After drying, the grain structure was observed using an optical microscope in polarized light mode, and photographs were taken for grain size measurement.

[0188] Figure 1a , Figure 1b , Figure 2a and Figure 2b The particle and grain structure of Example 1 and Example 14 of the present invention are shown respectively. The core layer grains of the present invention are small and uniform equiaxed grains. Such grains have a good effect on improving the strength and elongation of the material, and are conducive to the formation of more cubic textures, which in turn facilitates the forming of the material. The composite layer of the present invention has uniform grains, which can reduce the defects of material texture after anodizing caused by uneven grain structure and improve the surface quality of anodized material.

[0189] Representation of texture

[0190] The prepared sample plates were cut into 20 mm × 20 mm pieces and mounted, with the rolling direction of the sample used as the observation surface. A thick plate was used as a protective plate and conductive contact surface. Then, rough grinding, fine grinding, polishing, and final polishing were performed sequentially to prepare the required metallographic specimens. EBSD testing was then performed using a FEI NOVA NANO SEM200 field emission electron microscope equipped with an EBSD probe. After the testing, Aztec Crystal software was used for data processing to obtain texture percentage data. The texture percentages of each embodiment and comparative example are shown in Table 6 below.

[0191] Table 6

[0192] Performance testing

[0193] The sample plates prepared above were used as test materials and evaluated according to the method shown below. The results are shown in Table 7.

[0194] (1). Mechanical performance testing The material was prepared into tensile test specimens according to the EN10002-1 standard, with a gauge length of 50 mm, and tensile tests were conducted at room temperature at a tensile speed of 20 mm / min.

[0195] (2). Surface quality after rapid anodizing The surface quality of the material samples was assessed according to GB / T12967.6-2022 Test Methods for Anodized Films of Aluminum and Aluminum Alloys Part 6: Visual Inspection of Color Difference and Appearance Quality of Colored Anodized Films.

[0196] Table 7

[0197] As shown in Table 7, the aluminum composite materials of Examples 1-23 exhibit high strength. At the same material thickness, compared to using a single-layer aluminum alloy, the aluminum alloy composite material of this invention significantly improves the material's strength. Furthermore, the composite material of this invention achieves high anodized surface quality. Surface quality assessment according to GB / T12967.6-2022 "Test Methods for Anodized Films of Aluminum and Aluminum Alloys Part 6: Visual Inspection of Color Difference and Appearance Quality of Colored Anodized Films" shows that the materials of the embodiments of this invention have uniform color after anodizing, and ΔE is below 0.9 for all. This invention improves material strength by adding more reinforcing elements to the core layer alloy through a combination design. Moreover, this invention selects a suitable composite layer alloy, achieving a good anodizing effect while simultaneously meeting the requirements for both strength and anodizing performance. In addition, the selection of the core layer alloy in this invention does not require deliberately avoiding some reinforcing elements that affect the anodizing effect; therefore, more waste materials can be used to produce the core layer alloy, achieving the goals of cost control and green low-carbon development. In summary, the aluminum alloy composite material for anodizing of this invention has both high strength and good anodizing effect, and it is also a low-cost, low-carbon aluminum product with broad market application prospects.

Claims

1. An aluminum alloy composite material comprising a core layer and at least one composite layer, characterized in that, The composite layer contains one or more alloys from the AA1XXX, AA5XXX, and AA6XXX series; The core layer contains Fe, Cu, Mn, Si, Mg, Zn, Zr, Ti, Cr, and Al. Among them, based on the total weight of the core material layer, in the core material layer... The total content of Fe, Cu and Mn is 0.6 to 3.3% by weight; and / or The total content of Zn, Zr, Ti and Cr is 0.08 to 0.52% by weight. Among them, based on the total weight of the core material layer, the core material layer contains: The Fe content is 0.3 to 0.7% by weight. The Cu content is 0.25 to 0.6% by weight. The Mn content is 0.05% to 2% by weight. The Si content is 0.2% to 1% by weight. The Mg content is 0.5 to 5.5% by weight. The Zn content is 0.03 to 0.3% by weight. The Zr content is 0.01 to 0.06% by weight. The Ti content is 0.03 to 0.1% by weight. The Cr content is 0.01 to 0.06 by weight.

2. The aluminum alloy composite material according to claim 1, characterized in that, Based on the total weight of the raw materials of the core layer, the raw materials of the core layer contain more than 70% by weight of aluminum alloy scrap.

3. The aluminum alloy composite material according to claim 2, characterized in that, The aluminum alloy scrap is selected from: process scrap, post-consumer scrap and combinations thereof, wherein the post-consumer scrap contains 0.05 to 2% by weight of Mn.

4. The aluminum alloy composite material according to claim 3, characterized in that, The post-consumer waste also includes one or more of the following elements: 0.1 to 0.5% by weight of Si; 0.02 to 0.3% by weight of Cu; 0.3 to 3.5% by weight of Mg; 0.02 to 0.2% by weight of Zn.

5. The aluminum alloy composite material according to claim 3, characterized in that, The post-consumption waste contains 3XXX and / or 5XXX alloys.

6. The aluminum alloy composite material according to claim 3, characterized in that, The process waste is the waste generated during the preparation of the aluminum alloy composite material according to claim 1; and / or The post-consumer waste refers to waste from 3C products.

7. The aluminum alloy composite material according to claim 1, characterized in that, The grain size of the core material layer is 10 to 60 μm.

8. The aluminum alloy composite material according to claim 1, characterized in that, The core material layer contains a cubic texture.

9. The aluminum alloy composite material according to claim 8, characterized in that, The area of ​​the cubic texture accounts for 8 to 14% of the total area of ​​the material.

10. The aluminum alloy composite material according to claim 1, characterized in that, The composite layer can be one, two, or more layers. When the composite layer is two layers, the two composite layers are located on both sides of the core material layer.

11. The aluminum alloy composite material according to claim 10, characterized in that, The composite ratio of the composite layer is 5% to 35%.

12. The aluminum alloy composite material according to any one of claims 1-11, characterized in that, It has one or more of the following properties: (a) Yield strength Rp0.2 ranges from 180 to 400 MPa; (b) Tensile strength Rm is 200 to 450 MPa; (c) The color difference ΔE of the anodic oxide film evaluated in accordance with GB / T12967.6-2022 is less than 1.

0.

13. Use of the aluminum alloy composite material according to any one of claims 1-12 in anodizing coloring.

14. An electronic product comprising the aluminum alloy composite material according to any one of claims 1-12.

15. A method for preparing an aluminum alloy composite material according to any one of claims 1-12, characterized in that, The method includes: Preparation of core layer alloys and composite layer alloys; The core layer alloy and the composite layer alloy are heat-treated separately. A composite material is obtained by combining a core layer alloy and a composite layer alloy. The composite is heat-treated and then rolled to the target thickness; annealing.

16. The method according to claim 15, characterized in that, The step of preparing the core layer alloy includes adding aluminum alloy scrap.

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