Aluminum alloy and preparation method and application thereof

Abstract

The invention discloses an aluminum alloy and a preparation method and application thereof, and the aluminum alloy comprises the following components in percentage by weight: 4.0 to 6.0 percent of Si, 0.8 to 1.0 percent of Cu, 0.04 to 0.15 percent of Mn, 0.7 to 1.0 percent of Mg, 0.05 to 0.10 percent of Cr, 0.7 to 1.1 percent of Ni, 0.02 to 0.08 percent of Sr, 0.08 to 0.15 percent of Ce, 0.006 to 0.02 percent of Ti, less than or equal to 0.05 percent of Zn, less than or equal to 0.12 percent of Fe, less than 0.1 percent of other impurities and the balance of Al. Through the design of chemical components and the production process of adjusting the manufacturing procedure, the elasticity modulus of the material is improved on the premise that it is guaranteed that the material has the anode performance and the mechanical performance.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, specifically to an aluminum alloy, its preparation method, and its application. Background Technology

[0002] With the rapid development of mobile communication technology, smartphones have become an indispensable part of modern people's daily lives. As a core component of smartphones, the phone frame not only bears the important task of supporting and protecting the internal structure, but also directly affects the user's grip and the overall aesthetics of the device. Therefore, the selection and design of the phone frame's materials are particularly important.

[0003] As a unified structural and decorative component, aluminum alloy is an ideal material for mobile phone frames due to its low density, high strength, and good machinability. However, traditional aluminum alloys have a relatively low modulus of elasticity, which limits the rigidity and deformation resistance of the mobile phone frame to some extent. Especially with the increasing trend towards thinner and lighter mobile phones, improving the rigidity and deformation resistance of the mobile phone frame material while maintaining lightweight design and aesthetic appeal has become a pressing issue. Aluminum alloys used for electronic structural components typically employ AlMgSi(Cu) or AlZnMg(Cu) alloys. These materials are easy to process and have excellent anodizing properties, but their modulus of elasticity cannot reach higher levels. Furthermore, the improvement of the modulus of elasticity is not significantly related to the material's heat treatment or processing state. Currently, the industry uses composite materials with added SiC and other ceramic particles to achieve high modulus of elasticity. However, these materials are not suitable for anodizing and can only be used for structural components that are not aesthetically pleasing. This not only increases the design difficulty of the product but also raises the processing and production costs.

[0004] Therefore, there is an urgent need to provide an aluminum alloy with medium to high strength, good anodized appearance, and high elastic modulus. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an aluminum alloy that, through the design of chemical composition and adjustment of manufacturing process, improves the elastic modulus of the material while ensuring the material has anodic and mechanical properties.

[0006] The present invention also proposes a method for preparing the above-mentioned aluminum alloy.

[0007] The present invention also proposes an application of the above-mentioned aluminum alloy in electronic structural components.

[0008] According to one aspect of the present invention, an aluminum alloy is provided, comprising, by weight percentage, the following components: Si: 4.0–6.0%, Cu: 0.8–1.0%, Mn: 0.04–0.15%, Mg: 0.7–1.0%, Cr: 0.05–0.10%, Ni: 0.7–1.1%, Sr: 0.02–0.08%, Ce: 0.08–0.15%, Ti: 0.006–0.02%, Zn ≤ 0.05%, Fe ≤ 0.12%, other impurities < 0.1%, and the balance being Al.

[0009] In aluminum alloys, the coexistence of Si and Mg elements forms age-hardening phases such as Mg2Si. The tensile strength of the alloy increases with increasing Si and Mg content, but the strength increase becomes less significant with further increases in Mg and Si content. Instead, it leads to the formation of large amounts of coarse MgSi compounds, increasing production costs and difficulty. These coarse compounds also negatively impact the anodizing effect. Excess Si, besides refining MgSi particles, also forms Fe-containing compounds with Fe. While Si can improve the final strength and elastic modulus of the material—in pure aluminum, a 1% increase in Si can increase tensile strength by approximately 40 MPa—excessive Si produces coarse primary Si particles. Furthermore, when Si is excessive, it affects the solid solubility of Mg and Cu elements, not only diminishing the strength improvement but also potentially decreasing it. It also significantly reduces processing performance and anodizing effect. Therefore, this alloy is designed with Si content of 4.0–6.0, combined with other alloying elements and production processes to achieve extreme refinement and fragmentation, maximizing material strength and elastic modulus while balancing the anodizing effect.

[0010] In aluminum alloys, Cu can improve the dispersion of precipitated phases and form the AlMgSi(Cu) phase together with Mg and Si. At the same time, some Cu also plays a role in solid solution strengthening. Excessive Cu will form the AlCuMg phase or CuAl2. These phases have a large potential difference with the matrix and increase the processing difficulty of the material, leading to cracking during processing. At the same time, this phase is also relatively difficult to dissolve, thus affecting the anode effect and production difficulty of the material. This invention is designed with a concentration of 0.8% to 1.0%.

[0011] Mn and Cr elements form micron-sized dispersed phases in aluminum alloys, which can effectively improve the dispersion of other compounds and effectively inhibit grain nucleation and growth during hot working or heat treatment. They can effectively control the grain size of the material and significantly improve the corrosion resistance and mechanical properties of the material. However, they have little effect on the elastic modulus. Mn can effectively promote the formation of coarse Fe phases during casting and homogenization processes.

[0012] Ni has a solid solubility of 0.04% in aluminum alloys. It can form Al3Ni compounds or insoluble intermetallic compounds with Fe, which can play a role in dispersion strengthening. Therefore, the strength increases with increasing content, but generally does not exceed 2%. The addition of Ni can increase the compositional supercooling at the solid / liquid interface, which can refine the grains. Furthermore, the solid solution can cause a certain degree of lattice distortion, increasing strength. In Al-Si alloys, it can improve high-temperature hardness, high-temperature strength, and reduce the coefficient of thermal expansion. More importantly, the increase in Ni content leads to a linear increase in the bulk elastic modulus of the nickel-aluminum intermetallic compound. Therefore, Ni has a direct impact on the elastic modulus of the alloy. However, excessive Ni compounds can affect the transparency of the anodized film, thus affecting the anodizing effect.

[0013] Fe is an unavoidable harmful impurity in alloys, especially for materials that undergo subsequent anodizing treatment. In the alloy material of this invention, it can form intermetallic compounds with Si and Ni. Although it can refine the grains, its effect on improving the elastic modulus is not significant. Therefore, this invention controls the upper limit of its content.

[0014] Ce is a rare earth element. Adding Ce to aluminum alloys can improve the material's fluidity and processing performance. It can also improve the casting microstructure of Fe and Si, promote the transformation of Fe into a non-acicular structure, effectively refine the distribution of Si, reduce eutectic Si structure, and effectively enhance the plasticity and elastic modulus of high-Si alloys. Furthermore, it can act as a heterogeneous nucleation agent, further improving the material's plasticity and elastic modulus. Finally, Ce can improve the uniformity of the material's microstructure and the effectiveness of homogenization treatment, and enhance the material's corrosion resistance. However, excessive addition not only increases production costs but also reduces the anodizing effect.

[0015] As a surface-active element, sulfur (Sr) can alter the behavior of intermetallic compounds through crystallography. When added to alloys, Sr promotes the transformation of acicular Si phases into globular phases and the formation of globular AlFeSi-type crystalline phases. This helps reduce stress concentration, improves the strength and plasticity of the as-cast alloy, enhances the fluidity and solidification of aluminum alloys, reduces casting shrinkage cavities and hot cracks, and improves the density and mechanical properties of castings. However, Sr is easily burned off, and excessive addition does not lead to a linear increase in effect; instead, it increases production costs.

[0016] Ti is a grain refining element. In this invention, 0.006% to 0.02% Ti is added to refine the grain structure during casting and processing.

[0017] In some embodiments of the present invention, the components, by weight percentage, include the following: Si: 5.5–6.0%, Cu: 0.95–1.0%, Mn: 0.09–0.13%, Mg: 0.77–1.0%, Cr: 0.066–0.10%, Ni: 0.96–1.1%, Sr: 0.04–0.08%, Ce: 0.13–0.15%, Ti: 0.010–0.02%, Zn ≤ 0.05%, Fe ≤ 0.12%, other impurities < 0.1%, and the balance being Al.

[0018] A second aspect of the present invention provides a method for preparing the above-mentioned aluminum alloy, comprising the following steps:

[0019] S1: Melt, refine, purify, and cast aluminum ingots and raw materials containing the aforementioned components to obtain aluminum alloy ingots;

[0020] S2: Aluminum alloy ingot obtained from homogenization step S1.

[0021] In some embodiments of the present invention, in step S1, the melting temperature is 750–780°C.

[0022] The above melting temperature can better melt the AlNi master alloy and improve the uniformity of Ni element. After the aluminum ingot is completely melted, aluminum-silicon alloy, magnesium ingot, manganese agent and other master alloys are added in a certain proportion to alloy the aluminum melt. Ti is added online in the form of a refiner. AlNi10 is used as the AlNi master alloy.

[0023] In some embodiments of the present invention, in step S1, the refining temperature is 730–750°C.

[0024] In some embodiments of the present invention, the refining time in step S1 is 20 to 40 minutes.

[0025] In some embodiments of the present invention, during the refining process, high-purity argon gas is introduced into the molten aluminum through the permeable bricks at the bottom of the furnace for stirring, and after venting, slag is removed.

[0026] In some embodiments of the present invention, the slag removal process further includes sampling and analyzing the chemical composition to control the alloy composition within the range of the stated weight percentage.

[0027] In some embodiments of the present invention, the process of obtaining an aluminum melt after melting further includes stirring the aluminum melt, wherein the stirring method includes at least one of electromagnetic stirring, stirring with permeable bricks in the furnace, and mechanical stirring.

[0028] The obtained aluminum melt was continuously stirred to avoid the sedimentation of heavier elements affecting the uniformity of material composition. AlSr master alloy was added within 20 minutes before casting to reduce element burn-off.

[0029] In some embodiments of the present invention, step S1 includes the purification step of passing the aluminum melt through a degassing device and a filtration system in sequence.

[0030] The molten aluminum is passed through a box-type degassing device and a filtration system for deep purification. The degassing effect reaches below 0.15ml / 100gAl. The filtration uses foam ceramic filter plates with a minimum of 60ppi, tubular filters with a minimum RB grade, or deep bed filtration.

[0031] In some embodiments of the present invention, in step S1, the casting temperature is 690–720°C.

[0032] In some embodiments of the present invention, in step S1, the casting method includes a semi-continuous water-cooled casting method.

[0033] In some embodiments of the present invention, the parameters of the homogenization process in step S2 include: holding at 500℃~535℃ for 16~24h.

[0034] In some embodiments of the present invention, the preparation method further includes plastic deformation of the aluminum alloy ingot in step S2; the plastic deformation method includes hot extrusion or rolling.

[0035] In some embodiments of the present invention, when the plastic deformation method is hot extrusion, the hot extrusion steps include: extruding, quenching, straightening, and then heat treating the aluminum alloy ingot from step S2.

[0036] In some embodiments of the present invention, the extrusion temperature is 480–510°C.

[0037] In some embodiments of the present invention, the extrusion ratio is 60 to 80, and the discharge speed during the extrusion process is 6 to 12 m / min.

[0038] In some embodiments of the present invention, the quenching step involves a cooling rate ≥ 500°C / min.

[0039] In some embodiments of the present invention, the straightening stretch is 0.5% to 1.5%.

[0040] In some embodiments of the present invention, the heat treatment conditions are 160-200℃ for 2-8 hours.

[0041] In some embodiments of the present invention, when the plastic deformation method is rolling, the rolling steps include: rolling the aluminum alloy ingot from step S2, solution heat treatment, quenching, straightening, and aging treatment.

[0042] In some embodiments of the present invention, the rolling process includes at least one of hot rolling and cold rolling.

[0043] In some embodiments of the present invention, the hot rolling temperature is 400–470°C.

[0044] In some embodiments of the present invention, the temperature of the cold rolling is 0 to 300°C.

[0045] Depending on product requirements and the rolling cracking situation, hot rolling, cold rolling, or a combination of both rolling processes are used, with the overall rolling thickness deformation exceeding 80%.

[0046] In some embodiments of the present invention, the temperature of the solution heat treatment is 500-535°C, and the holding time of the solution heat treatment is 30-90 min.

[0047] In some embodiments of the present invention, the quenching method includes water quenching.

[0048] In some embodiments of the present invention, the quenching transfer time is ≤10s.

[0049] In some embodiments of the present invention, the straightening stretch is 0.5% to 1.5%.

[0050] In some embodiments of the present invention, the aging treatment conditions are: heat preservation at 160-200°C for 2-8 hours.

[0051] Within the scope of this invention, the properties of materials (parts) obtained from homogenization heat treatment, ingot heating, and processing will vary depending on the component ratio and processing method, but the overall characteristics of the materials are as follows:

[0052] 1. Yield strength ≥ 320 MPa in heat-treated state, elongation after fracture A 50 ≥10%.

[0053] 2. This alloy has a high elastic modulus, with the elastic modulus of the extruded material ≥80GPa and the elastic modulus of the rolled material ≥85GPa.

[0054] 3. The second phase particles of this alloy have a particle size of <12μm and a particle area ratio of ≤20%, and can be used as an appearance part for anodizing treatment.

[0055] A third aspect of the present invention proposes an application of the above-mentioned aluminum alloy in electronic structural components. Detailed Implementation

[0056] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Attached Figure Description

[0057] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0058] Figure 1 Metallographic image of Example 2;

[0059] Figure 2 The metallographic diagram is for Comparative Example 1;

[0060] Figure 3 This is the metallographic diagram of Comparative Example 2;

[0061] Figure 4 The metallographic diagram is for Comparative Example 3;

[0062] Figure 5 The metallographic diagram is for Comparative Example 4;

[0063] Figure 6 This is the metallographic diagram of Comparative Example 11.

[0064] Raw materials in the embodiments of the present invention:

[0065] Aluminum ingots: Al99.7 grade aluminum ingots are used, with an Al mass percentage of over 99.70%, conforming to standard GB / T 1196-2017 "Aluminum ingots for remelting";

[0066] Magnesium ingots: Magnesium ingots of grade Mg9990 are used, with a Mg content of over 99.9% by mass, conforming to standard GB / T 3499-2003 "Primary Magnesium Ingots";

[0067] Alloy additives: Si is added using AlSi20 master alloy, Cu using pure copper, Cr using AlCr10 master alloy, Mn using AlMn10 master alloy, Ce using AlCe10 master alloy, Ni using AlNi10 master alloy, Sr using AlSr5 master alloy, and Ti is added as a grain refiner. The quality of the master alloys conforms to GB / T27677-2017 standard, and the grain refiner conforms to YS / T 447.1-2011 Alloy wires for grain refinement of aluminum and aluminum alloys, Part 1: Aluminum-titanium-boron alloy wires.

[0068] Refining gas: High-purity argon gas is used, with a purity (volume percentage) of ≥99.999%;

[0069] Gas processing in the online smelting process: High-purity argon gas is used, with a purity (volume percentage) of ≥99.999%.

[0070] Example 1

[0071] This embodiment describes an aluminum alloy and its preparation method. The specific content is shown in Table 1.

[0072] The specific steps are as follows:

[0073] 1. Manufacturing of aluminum alloy round ingots:

[0074] (1) Raw material preparation: Prepare the chemical composition as shown in Table 1;

[0075] (2) Loading the furnace: Load the aluminum ingots from the above raw materials into the smelting furnace (regenerative energy-saving furnace);

[0076] (3) Heating and melting: The temperature inside the furnace is controlled at 750℃ so that the aluminum ingot is completely melted into aluminum melt I;

[0077] (4) Alloying: Add AlSi20 and AlMn10 to aluminum melt I. After they are fully melted, add the above magnesium ingots and other intermediate alloys and stir to melt them. Finally, add AlNi10 to perform preliminary alloying of the melt to obtain aluminum melt II.

[0078] (5) Refining: Add refining agent to the aluminum melt II obtained in step (4) at a dosage of 1 kg / ton of aluminum melt II. The refining temperature is 730-750℃ and the refining time is 20-40 minutes. During the refining process, the aluminum melt obtained will be chemically analyzed. If the alloy composition is not within the range described in step (1), the alloy composition will be controlled within the range described in step (1) by fine-tuning the composition. At the same time as refining, high-purity argon gas is introduced into the aluminum melt through the permeable brick at the bottom of the furnace for stirring and exhaust. Then, the slag is removed to obtain aluminum melt III. The argon gas pressure is controlled at 0.05-0.1 MPa and the flow rate is controlled at 10 L / min.

[0079] (6) Alloy composition analysis: Alloy element analysis is performed on the melt III obtained after refining in step (5). If the alloy composition is not within the range described in step (1), the alloy composition is controlled within the range described in step (1) by fine-tuning the composition.

[0080] (7) Stirring treatment: The aluminum melt III is continuously stirred. The stirring method is to continuously introduce high-purity argon into the aluminum melt through the permeable bricks in the furnace. Add AlSr intermediate alloy within 20 minutes before casting.

[0081] (8) Online degassing: Hydrogen is removed by using a degassing device to control the hydrogen content of aluminum melt IV to below 0.15 ml / 100 g Al aluminum;

[0082] (9) Online filtration: Purification is carried out using a two-stage filtration system with 40+80 mesh foam ceramic filter plates;

[0083] (10) Casting: The semi-continuous water-cooled casting method is adopted, the casting temperature is controlled at 690-700℃, and an appropriate amount of Al-3Ti-1B refining agent is added online. During the casting process, the permeable brick is continuously ventilated and stirred to obtain aluminum alloy round or square ingots.

[0084] (11) Homogenization treatment: The obtained alloy ingot is heated to 520°C in a homogenization heat treatment furnace and held for 24 hours. Then it is cooled to room temperature with water mist to obtain an aluminum alloy round ingot that meets the requirements of this invention.

[0085] 2. Manufacturing of aluminum extruded profiles:

[0086] (1) Cut the aluminum alloy round ingot (aluminum rod) obtained above into 600mm lengths, and put the short rods into the aluminum rod heating furnace to heat the aluminum rods to 480℃;

[0087] (2) The aluminum alloy round ingot is loaded into the extrusion press for extrusion. The extrusion ratio (extrusion coefficient: the ratio of the cross-sectional area of ​​the extrusion cylinder to the total cross-sectional area of ​​the extruded product) is 72, the extrusion speed (discharge speed) is 8m / min, and the extrusion outlet temperature is 510~530℃.

[0088] (3) After the alloy product comes out of the die, it enters the quenching zone within 8 seconds and is cooled by direct water cooling at a rate of 600℃ / min.

[0089] (4) Tensile deformation: The alloy material is stretched using a stretching machine, and the stretching amount is controlled within 0.8%.

[0090] (6) Heat treatment process: 175℃ for 6 hours.

[0091] Example 2

[0092] This embodiment is an aluminum alloy and its preparation method. The specific content is shown in Table 1, and the specific steps are the same as those in Embodiment 1.

[0093] Example 3

[0094] This embodiment describes an aluminum alloy and its preparation method. The specific content is shown in Table 1. The alloy is prepared by rolling, and the specific steps are as follows:

[0095] 1. Manufacturing of aluminum alloy round ingots:

[0096] (1) Raw material preparation: Prepare the chemical composition as shown in Table 1;

[0097] (2) Loading the furnace: Load the aluminum ingots from the above raw materials into the smelting furnace (regenerative energy-saving furnace);

[0098] (3) Heating and melting: The temperature inside the furnace is controlled at 750℃ so that the aluminum ingot is completely melted into aluminum melt I;

[0099] (4) Alloying: Add AlSi20 and AlMn10 to aluminum melt I. After they are fully melted, add the above magnesium ingots and other intermediate alloys and stir to melt them. Finally, add AlNi10 to perform preliminary alloying of the melt to obtain aluminum melt II.

[0100] (5) Refining: Add refining agent to the aluminum melt II obtained in step (4) at a dosage of 1 kg / ton of aluminum melt II. The refining temperature is 730-750℃ and the refining time is 20-40 minutes. During the refining process, the aluminum melt obtained will be chemically analyzed. If the alloy composition is not within the range described in step (1), the alloy composition will be controlled within the range described in step (1) by fine-tuning the composition. At the same time as refining, high-purity argon gas is introduced into the aluminum melt through the permeable brick at the bottom of the furnace for stirring and exhaust. Then, the slag is removed to obtain aluminum melt III. The argon gas pressure is controlled at 0.05-0.1 MPa and the flow rate is controlled at 10 L / min.

[0101] (6) Alloy composition analysis: Alloy element analysis is performed on the melt III obtained after refining in step (5). If the alloy composition is not within the range described in step (1), the alloy composition is controlled within the range described in step (1) by fine-tuning the composition.

[0102] (7) Stirring treatment: The aluminum melt III is continuously stirred. The stirring method is to continuously introduce high-purity argon into the aluminum melt through the permeable bricks in the furnace. Add AlSr intermediate alloy within 20 minutes before casting.

[0103] (8) Online degassing: Hydrogen is removed by using a degassing device to control the hydrogen content of aluminum melt IV to below 0.15 ml / 100 g Al aluminum;

[0104] (9) Online filtration: Purification is carried out using a two-stage filtration system with 40+80 mesh foam ceramic filter plates;

[0105] (10) Casting: The semi-continuous water-cooled casting method is adopted, the casting temperature is controlled at 690-700℃, and an appropriate amount of Al-3Ti-1B refining agent is added online. During the casting process, the permeable brick is continuously ventilated and stirred to obtain aluminum alloy round or square ingots.

[0106] (11) Homogenization treatment: The obtained alloy ingot is heated to 520°C in a homogenization heat treatment furnace and held for 24 hours. Then it is cooled to room temperature with water mist to obtain an aluminum alloy round ingot that meets the requirements of this invention.

[0107] 2. Manufacturing of rolled aluminum profiles:

[0108] (1) Process the outer surface of the raw material to remove the epidermal tissue.

[0109] (2) The processed billet is rolled at a hot rolling temperature of 450°C. About 20% of the rolling deformation is reserved for room temperature rolling, and the overall thickness deformation is 87%.

[0110] (3) The solution heat treatment process is to keep it at 525℃ for 45 minutes.

[0111] (4) Quenching is performed by direct water cooling, with a quenching transfer time of 8s.

[0112] (5) Straightening is performed using a stretching process, with a stretching deformation of 1.2%.

[0113] (6) The artificial aging process conditions are: 180℃ for 4 hours.

[0114] Comparative Example 1

[0115] An aluminum alloy was prepared in this comparative example. The chemical composition of this comparative example is shown in Table 1. The other conditions are the same as those in Example 2.

[0116] Comparative Examples 2-4

[0117] An aluminum alloy was prepared in Comparative Examples 2-4. The chemical composition of Comparative Examples 2-4 is shown in Table 1. The other conditions were the same as those in Example 1.

[0118] Comparative Example 5

[0119] An aluminum alloy was prepared in this comparative example. The chemical composition of this comparative example is the same as that of Example 2. The overall deformation amount of the rolling process used is 70%, and other conditions are the same as those of Example 2.

[0120] Comparative Examples 6–9

[0121] An aluminum alloy was prepared in Comparative Examples 6-9. The chemical composition of the comparative examples is shown in Table 1. Other conditions were the same as in Example 1.

[0122] Comparative Example 10

[0123] An aluminum alloy was prepared in this comparative example. The chemical composition of this comparative example is the same as that of Comparative Example 6, and the other conditions are the same as those of Example 2.

[0124] Comparative Examples 11 and 12

[0125] An aluminum alloy was prepared in this comparative example. The chemical composition of this comparative example is shown in Table 1. Other conditions are the same as those in Example 2.

[0126] Comparative Example 13

[0127] An aluminum alloy was prepared in this comparative example. The chemical composition of this comparative example is shown in Table 1. Other conditions were the same as in Example 1.

[0128] Table 1. Mass percentage of each component in the aluminum alloy (wt%)

[0129]

[0130]

[0131] The performance test results of the examples and comparative examples are shown in Table 2:

[0132] Table 2 Mechanical property test results

[0133]

[0134]

[0135] Testing standards:

[0136] The base material is based on GB / T 228.1 metallic materials—tensile testing—part 1: room temperature test method;

[0137] GB / T 2651 Tensile testing method for welded joints;

[0138] The heat input for TIG welding is the welding strength coefficient, which is the strength after welding divided by the strength of the base material before welding.

[0139] The results in Table 2 show that, in Comparative Example 1, the high-Si chemical composition, while increasing the elastic modulus of the material to some extent, did not significantly improve its strength, unlike Example 2 (see Table 2). Figure 1 Compared to the previous method, this resulted in the production of larger compound particles, which also led to a significant increase in the area ratio of the compound (see...). Figure 2 This results in a numbness defect in the material after anodizing. Figure 1 As can be seen, the material has a uniform grain structure, the second phase particles are relatively uniformly distributed, and the particle size is small, which meets the design requirements. The aluminum alloy material of Example 2 has a high elastic modulus and good mechanical properties, and the particle size and distribution are uniform, making it suitable for anodizing treatment and resulting in a good appearance.

[0140] Comparative Example 2 increased the Ni content compared to Example 1, but the increase in Ni content did not significantly improve the elastic modulus; instead, it produced a large number of large-sized compound particles (see...). Figure 3This not only reduces the elongation after fracture of the material, but also seriously affects the anodizing effect of the material.

[0141] Compared to Example 2, Comparative Example 3 had a Cu content of 1.08%, which improved the mechanical properties to some extent. However, because Cu increases the processing difficulty of the material, cracks appeared during the rolling process (see...). Figure 4 This leads to a significant decrease in the elongation of the material, and the increased Cu content also reduces the material's corrosion resistance, resulting in fogging at the anode of the final material.

[0142] Compared to Example 1, Comparative Example 4 increased the Mg content. However, because Mg₂Si has a certain limitation on solid solution under process conditions that prevent over-burning, a certain number of fine reinforcing phases cannot be completely dissolved (see...). Figure 5 This results in a lack of significant strength improvement, which in turn affects the anodizing effect.

[0143] Compared with Example 2, Comparative Example 5 reduced the total rolling deformation. Due to insufficient material deformation, the lattice distortion was insufficient and the second phase particles were not refined enough, thereby reducing the effect of the elements and causing the elastic modulus of the final material to fail to reach the expected value.

[0144] Compared with Example 2, Comparative Examples 6 and 7 reduced the content of Si and Ni elements. Since Si and Ni elements are mainly responsible for ensuring the elastic modulus, the reduction in their content resulted in the elastic modulus failing to meet the expected requirements.

[0145] Compared with Example 2, Comparative Examples 8 and 9 reduced the content of Mg and Cu elements, thereby reducing the content of Mg2Si and AlMgSi(Cu) reinforcing phases. As a result, the final strength decreased significantly, causing the strength to fail to meet the requirements.

[0146] Comparative Example 10 has the same chemical composition as Comparative Example 6 and is produced using a rolling process. However, due to the reduction in Si content, the rolling process could not achieve the expected elastic modulus requirement.

[0147] Compared to Example 3, Comparative Example 11 reduced the levels of Mn and Cr, thus eliminating the trace element control over grain growth, resulting in an uneven grain structure during heat treatment (see...). Figure 6 The coarseness and inhomogeneity of the grains lead to a decrease in the elastic modulus and elongation of the material, and mottled defects appear after anodizing.

[0148] Compared with Example 3, Comparative Example 12 reduced the Sr content, so Si could not undergo maximum modification during the casting process. As a result, the final Si particles exceeded the 12μm requirement, which not only caused the elastic modulus to fail to meet the expected requirements, but also prevented the spheroidization of the Fe-containing phase to the maximum extent, resulting in the final anode exhibiting a fogging problem.

[0149] Compared with Example 1, Comparative Example 13 reduced the Ce content, which resulted in insufficient Ni refinement, leading to a lower elongation of the material and failing to maximize the effect of Ni in improving the elastic modulus. Consequently, the elastic modulus of the final material did not meet the requirements.

[0150] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An aluminum alloy, characterized in that, By weight percentage, it includes the following components: Si: 4.0–6.0%, Cu: 0.8–1.0%, Mn: 0.04–0.15%, Mg: 0.7–1.0%, Cr: 0.05–0.10%, Ni: 0.7–1.1%, Sr: 0.02–0.08%, Ce: 0.08–0.15%, Ti: 0.006–0.02%, Zn ≤ 0.05%, Fe ≤ 0.12%, other impurities < 0.1%, and the balance being Al.

2. The aluminum alloy according to claim 1, characterized in that, By weight percentage, it includes the following components: Si: 5.5–6.0%, Cu: 0.95–1.0%, Mn: 0.09–0.13%, Mg: 0.77–1.0%, Cr: 0.066–0.10%, Ni: 0.96–1.1%, Sr: 0.04–0.08%, Ce: 0.13–0.15%, Ti: 0.010–0.02%, Zn ≤ 0.05%, Fe ≤ 0.12%, other impurities < 0.1%, and the balance being Al.

3. A method for preparing an aluminum alloy as described in claim 1 or 2, characterized in that, Includes the following steps: S1: Melt, refine, purify, and cast aluminum ingots and raw materials containing the aforementioned components to obtain aluminum alloy ingots; S2: Aluminum alloy ingot obtained from homogenization step S1.

4. The method for preparing the aluminum alloy according to claim 3, characterized in that, In step S2, the parameters of the homogenization process include: holding at 500℃~535℃ for 16~24h.

5. The method for preparing the aluminum alloy according to claim 3, characterized in that, The preparation method further includes plastic deformation of the aluminum alloy ingot in step S2; the plastic deformation method includes hot extrusion or rolling.

6. The method for preparing the aluminum alloy according to claim 5, characterized in that, When the plastic deformation method is hot extrusion, the hot extrusion steps include: extruding, quenching, straightening, and then heat treating the aluminum alloy ingot from step S2.

7. The method for preparing the aluminum alloy according to claim 6, characterized in that, The extrusion temperature is 480–510°C.

8. The method for preparing the aluminum alloy according to claim 5, characterized in that, The method of plastic deformation is rolling, and the rolling steps include: rolling the aluminum alloy ingot from step S2, solution heat treatment, quenching, straightening and aging treatment.

9. The method for preparing the aluminum alloy according to claim 8, characterized in that, The rolling process includes hot rolling and cold rolling; and / or, the temperature of the hot rolling is 400 to 470°C; and / or, the temperature of the cold rolling is 0 to 300°C.

10. The application of an aluminum alloy as described in claim 1 or 2 in electronic structural components.

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