An aluminum alloy and a method for manufacturing the same

Abstract

The application discloses an aluminum alloy and a preparation method thereof. The aluminum alloy comprises the following components in percentage by mass: Mg 0.80-0.92%, Si 0.60-0.76%, Cu 0.60-0.99%, Mn 0.05-0.20%, Fe≤0.10%, and the balance of Al and impurities. By reasonably controlling the contents of main alloy elements Mg, Si, alloy elements Cu, Mn, Fe and impurities, the aluminum alloy is free of common anode appearance defects such as blackening, yellowing and material lines after oxidation treatment, has uniform and delicate color and luster, and presents high brightness and transparent appearance characteristics, and is very suitable for manufacturing appearance structural parts of 3C products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aluminum alloy materials, and particularly relates to an aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy is an Al-Mg-Si alloy, has high specific strength, good hot forming property, excellent corrosion resistance, and can be anodized and colored, and has very wide application prospects in 3C (computer, communication, consumer electronics), rail transit, automobile, building, etc. fields. 6013 aluminum alloy is a heat-treatable deformed aluminum alloy, has excellent extrusion performance, good corrosion resistance and welding performance, and anodized oxidation is easy to obtain bright luster, and its profile is widely used in appearance structural parts of 3C products such as smart phones and tablet computers. The 6013 aluminum alloy contains Mg, Si, Cu, Mn, Cr, Fe and Al.

[0003] In recent years, the mobile phone frame has a high requirement on the anodic appearance, for example, when the aluminum alloy is applied to the flagship machine of mobile phone terminals such as Xiaomi, Huawei, OPPO and vivo, certain component regulation and optimization will be carried out on the basis of 6013 alloy to realize high-brightness anodic appearance under the premise of ensuring mechanical properties. Mg and Si as main alloying elements, their content and proportion will directly affect the content of precipitated phase β (Mg2Si). However, when too much Mg and Si are added, there are more primary coarse β phases in the alloy, since the self-corrosion potential of the coarse β phase is more negative than that of the Al matrix, the coarse β phase is preferentially corroded in the anodic oxidation process, which is easy to cause the phenomenon of dull and cloudy anodic appearance, and cannot achieve the high-brightness luster effect. Cu element is not only dissolved in the Al matrix to produce solid solution strengthening, but also participates in the formation process of S phase (Al2CuMg), θ phase (Al2Cu) and β phase precursor. When more Cu is added in the alloy, the mechanical properties are improved, but it may also cause the alloy to turn yellow after anodic oxidation coloring, which seriously affects the aesthetic property. Mn element in the alloy will form Al6Mn phase, which plays a role in refining recrystallized grains, but Mn element can also form coarse brittle phase α-Al (Fe, Mn) Si with Si and Fe elements, and this coarse phase is also not conducive to the high-brightness anodic appearance in the electrochemical reaction of anodic oxidation. SUMMARY

[0004] To solve the above technical problems, the application provides an aluminum alloy and a preparation method thereof. The aluminum alloy of the application reasonably adjusts the content of Mg, Si, Cu and Mn elements, and strictly controls the content of Fe and impurities, so that the aluminum alloy not only has certain mechanical properties, but also is beneficial to realizing high-brightness anode appearance; the aluminum alloy prepared by the preparation method of the aluminum alloy of the application has no anode appearance defects such as hairiness, yellowing and material lines, has uniform and delicate color and luster, and presents high-brightness and transparent appearance characteristics.

[0005] To achieve the above technical effects, the technical scheme adopted by the application is as follows:

[0006] In a first aspect, the application provides an aluminum alloy, which comprises the following components in mass percentage:

[0007]

[0008] The balance is Al and impurities, wherein the content of impurities is not more than 0.1%.

[0009] In some embodiments, the mass percentage of Cu is 0.70-0.97%.

[0010] In some embodiments, the mass percentage ratio C1=(Mg+Si) / Cu is 1.50-2.70.

[0011] In some embodiments, the mass percentage ratio C2=Si / Cu is 0.60-1.20.

[0012] In some embodiments, the mass percentage ratio C3=Mg / Si is 1.05-1.50.

[0013] In some embodiments, the mass percentage ratio C4=Cu / Mn is 5.00-17.00.

[0014] In a second aspect, the application provides a preparation method of the above-mentioned aluminum alloy, which comprises the following steps:

[0015] Alloying and casting the raw material components of the aluminum alloy to obtain an alloy ingot;

[0016] Homogenizing the alloy ingot to obtain a homogenized ingot;

[0017] Extruding the homogenized ingot to obtain an extruded profile;

[0018] Pre-stretching and straightening the extruded profile, and aging treatment to obtain a profile sheet;

[0019] Oxidizing the profile sheet to obtain the aluminum alloy.

[0020] In some embodiments, the homogenizing the alloy ingot rod comprises:

[0021] annealing the alloy ingot rod by heating the alloy ingot rod to a first temperature according to a preset mode, and holding the alloy ingot rod at the first temperature for a first time;

[0022] cooling the alloy ingot rod under a preset condition, and performing first sawing on the alloy ingot rod after the temperature of the alloy ingot rod is cooled to room temperature to obtain a homogenized ingot rod;

[0023] wherein the first temperature is 540-580℃, and the first time is 10-14 hours.

[0024] The aluminum alloy comprises the following components by mass percentage:

[0025]

[0026] the balance being Al and impurities.

[0027] In some embodiments, the extruding the homogenized ingot rod comprises:

[0028] annealing the homogenized ingot rod at a second temperature, setting the temperature at the extrusion outlet as a third temperature, extruding the homogenized ingot rod to obtain an extruded profile, and in-line quenching;

[0029] wherein the second temperature is 530-550℃, and the third temperature is 550-570℃.

[0030] In some embodiments, the aging treatment comprises at least one of a first aging treatment and a second aging treatment.

[0031] wherein the process of the first aging treatment is standing at 170-185℃ for 8-12 hours.

[0032] the process of the second aging treatment is standing at room temperature for 4-10 hours.

[0033] The beneficial effects of the present application include but are not limited to: the aluminum alloy of the present application reasonably adjusts the content of Mg, Si, Cu and Mn elements, and strictly controls the content of Fe and impurities, so that the aluminum alloy not only has certain mechanical properties, but also is beneficial to realizing high-brightness anode appearance. The aluminum alloy prepared by the preparation method of the aluminum alloy of the present application has no anode appearance defects such as monochrome, yellowing and material lines, has uniform and delicate color and luster, and presents high-brightness and transparent appearance characteristics.

[0034] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, further serve to explain the principles of the application. The drawings in the following description are of several embodiments of the application, and are not all the embodiments in the application. Those skilled in the art will readily obtain other drawings from these drawings without any creative work.

[0036] The various objects, features and advantages of the present application will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the accompanying drawings, who illustrate preferred embodiments of the application.

[0037] Figure 1 Process flow chart of preparation of aluminum alloy according to an embodiment.

[0038] Figure 2 Process flow chart of oxidation treatment of aluminum alloy according to an embodiment. DETAILED DESCRIPTION

[0039] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative work fall within the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in any manner without conflict.

[0040] The present application provides an aluminum alloy and a preparation method thereof.

[0041] The aluminum alloy of the exemplary embodiments of the present application comprises the following components in mass percentage: Mg 0.80-0.92%, Si 0.60-0.76%, Cu 0.6-0.99%, Mn 0.05-0.20%, Fe≤0.10%, and the balance of Al and impurities, wherein the content of the impurities is not more than 0.1%.

[0042] In the exemplary embodiments provided by the present application, the aluminum alloy comprises the following components in mass percentage: Mg 0.82-0.90%, Si 0.63-0.74%, Cu 0.65-0.97%, Mn 0.08-0.16%, Fe≤0.10%, and the balance of Al and impurities, wherein the content of the impurities is not more than 0.1%.

[0043] In the exemplary embodiments provided in the present application, the aluminum alloy contains the following components in mass percentage: Mg 0.85-0.90%, Si 0.65-0.72%, Cu 0.70-0.97%, Mn 0.10-0.15%, Fe≤0.10%, and the balance of Al and impurities, wherein the content of impurities is not more than 0.1%.

[0044] In the exemplary embodiments provided in the present application, the mass percentage of Cu is 0.70-0.97%.

[0045] In the exemplary embodiments provided in the present application, the mass percentage of Fe is≤0.05%.

[0046] The aluminum alloy of the present application, by reasonably adjusting the contents of Mg, Si, Cu and Mn elements, while strictly controlling the contents of Fe and impurities, not only has certain mechanical properties, but also is beneficial to realizing high-brightness anode appearance.

[0047] In the aluminum alloy formula, the content of Cu affects the strength of the aluminum alloy. The aluminum alloy with lower Cu content has lower strength. In order to improve the mechanical properties such as strength, a large amount of Cu needs to be added to the aluminum alloy. However, too much copper content will cause the aluminum alloy to appear yellow after oxidation treatment, and the brightness is reduced. In the exemplary embodiments provided in the present application, in order to ensure the mechanical properties of the aluminum alloy, the content of Cu is controlled to be 0.6-0.99%, the content of Cu can also be 0.65-0.97%, or 0.70-0.97%, and exemplarily 0.97%.

[0048] Strictly limiting the content of Fe can significantly reduce the number of coarse and insoluble phases such as α-Al(Fe, Mn)Si.

[0049] In addition, it has been found through research that when the content of Mn is too high, the effect of inhibiting recrystallization is too strong, the alloy forms a fiber structure after extrusion, and it is easy to form a grain pattern defect on the surface of the alloy after oxidation. At the same time, adding too much Mn element can promote the formation of insoluble phase α-Al(Fe, Mn)Si, and increase the risk of surface haze of the aluminum alloy after oxidation. However, when the content of Mn is too low, the effect of inhibiting recrystallization is too weak, which is not conducive to the formation of uniform and fine recrystallized structure, and the grains are prone to abnormal growth during extrusion, which may form a contrast difference after oxidation. Controlling the content of Mn within a reasonable range can avoid the problems of grain pattern defect, haze or contrast difference on the surface of the aluminum alloy after oxidation.

[0050] Under the premise of containing high content of Cu, the contents of Mg, Si, Mn and Fe are controlled, the content of Mg is 0.80-0.92%, the content of Si is 0.60-0.76%, the content of Mn is 0.05-0.20%, and the content of Fe is less than 0.1%, so that the size and quantity of the primary second phase formed in the alloy casting solidification process are controlled in a reasonable range; thus, after homogenization treatment, the elements are fully diffused, the size of part of the large-size second phase is reduced, part of the small-size second phase is dissolved into the matrix, and the total precipitation phase is relatively small and dispersed, thereby providing a basis for preparing aluminum alloy with high brightness appearance. The content of Mg can also be 0.82-0.90% or 0.85-0.90%; the content of Si can also be 0.63-0.74% or 0.65-0.72%; the content of Mn can also be 0.08-0.16% or 0.10-0.15%; and the content of Fe can also be controlled to be ≤0.05%.

[0051] In the example embodiments provided in the present application, the ratio C1=(Mg+Si) / Cu in mass percentage is 1.50-2.70.

[0052] In the example embodiments provided in the present application, the ratio C1=(Mg+Si) / Cu in mass percentage is 1.60-2.50.

[0053] In the example embodiments provided in the present application, the ratio C2=Si / Cu in mass percentage is 0.60-1.20.

[0054] In the example embodiments provided in the present application, the ratio C3=Mg / Si in mass percentage is 1.05-1.50.

[0055] By reasonably controlling at least one of the ratios C1=(Mg+Si) / Cu, C2=Si / Cu and C3=Mg / Si in mass percentage, the formation process of part of Cu-rich phase is affected, so that the aluminum alloy is oxidized to reduce the risk of yellow appearance. Among them, C1=(Mg+Si) / Cu is controlled to be 1.50-2.70, and can also be 1.60-2.50 or 1.60-2.30; C2=Si / Cu is controlled to be 0.60-1.20, and can also be 0.65-1.10 or 0.70-1.00; C3=Mg / Si is controlled to be 1.05-1.50, and can also be 1.10-1.45 or 1.20-1.40.

[0056] In the example embodiments provided in the present application, the ratio C4=Cu / Mn in mass percentage is 5.00-17.00.

[0057] The ratio of C4=Cu / Mn is controlled within a reasonable range, and after the aluminum alloy is oxidized, the surface is effectively prevented from forming defects such as material lines, haze or contrast difference. Among them, C4=Cu / Mn is controlled to be 5.00-17.00, and can also be 6.00-12.00, or 6.00-10.00.

[0058] It should be noted that in some embodiments of the present application, the aluminum alloy can also contain impurities, which are inevitably introduced in the production process, the type of impurities cannot be determined, and the content is extremely small and can be ignored.

[0059] In some embodiments of the present application, the aluminum alloy is suitable for products with high appearance requirements in the 3C field.

[0060] The preparation method of the aluminum alloy of the exemplary embodiments of the present application, as shown in Figure 1 , includes:

[0061] Step S100: Alloying and casting the raw material components of the aluminum alloy to obtain an alloy ingot;

[0062] Step S200: Homogenizing the alloy ingot to obtain a homogenized ingot;

[0063] Step S300: Extruding the homogenized ingot to obtain an extruded profile;

[0064] Step S400: Pre-stretching and straightening the extruded profile, and aging treatment to obtain a profile sheet;

[0065] Step S500: Oxidizing the profile sheet to obtain an aluminum alloy.

[0066] The preparation method of the aluminum alloy of the present application is designed according to the aluminum alloy formula of the present application, so that the finally prepared aluminum alloy has no anodic appearance defects such as haze, yellowing, and material lines, has uniform and delicate color, and has high brightness and transparent appearance characteristics.

[0067] In the exemplary embodiments provided in the present application, the homogenizing of the alloy ingot to obtain a homogenized ingot includes:

[0068] The alloy ingot is heated to a first temperature according to a predetermined mode, and annealed for a first time;

[0069] Under predetermined conditions, the alloy ingot is cooled to room temperature, and then subjected to first sawing to obtain a homogenized ingot.

[0070] The preset heating mode is a stepwise heating mode, and the stepwise heating of the alloy cast bar can improve the mechanical properties of the alloy. The first temperature is 540-580 DEG C, and the first time is 10-14 hours, which can homogenize the components in the aluminum alloy, remove residual stress, and improve the mechanical properties of the aluminum alloy profile; the first temperature can also be 550-570 DEG C or 560-570 DEG C, and the first time can also be 10.5-13.5 hours or 12-13 hours, and the first time can also be 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours. The cooling under the preset condition refers to air cooling.

[0071] In the example embodiment provided in the present application, the homogenized cast bar is extruded to obtain an extruded profile, which includes:

[0072] The homogenized cast bar is kept at the second temperature, the temperature at the extrusion outlet is set to the third temperature, the homogenized cast bar is extruded to obtain an extruded profile, and the extruded profile is quenched in line.

[0073] The second temperature is 530-550 DEG C, and the third temperature is 550-570 DEG C; the homogenized cast bar is heated to 530-550 DEG C by induction, and the temperature at the extrusion outlet is 550-570 DEG C, which is convenient for extrusion operation; if the second temperature or the third temperature is too low, it is difficult to perform the extrusion operation, and if the second temperature or the third temperature is too high, not only the cost is increased, but also the shape or performance of the extruded profile is affected; the second temperature can also be 535-545 DEG C, and the third temperature can also be 550-560 DEG C.

[0074] In the example embodiment provided in the present application, when the homogenized cast bar is extruded, the extrusion ratio is 30-60, and the extrusion speed is 20-150 mm / s.

[0075] When the homogenized cast bar is extruded, the extrusion ratio and the extrusion speed can also be controlled to obtain an extruded profile of a desired specification, wherein the extrusion ratio can be 30-60, and the extrusion speed can be 20-150 mm / s.

[0076] In the example embodiment provided in the present application, the aging treatment includes at least one of a first aging treatment and a second aging treatment.

[0077] The first aging treatment process is to stand for 8-12 hours at 170-185 DEG C.

[0078] The second aging treatment process is to stand for 4-10 hours at room temperature.

[0079] In the exemplary embodiments provided in the present application, the extruded profile is sequentially subjected to pre-stretch straightening, second sawing, first aging treatment, and third sawing to obtain the profile sheet.

[0080] The first aging treatment is artificial aging treatment, and the artificial aging treatment process is to stand for 8-12 hours at 170-185 DEG C.

[0081] In the exemplary embodiments provided in the present application, the extruded profile is sequentially subjected to pre-stretch straightening, second sawing, second aging treatment, and third sawing to obtain the profile sheet.

[0082] The second aging treatment is natural aging treatment, and the natural aging treatment process is to stand for 4-10 hours at room temperature.

[0083] In the exemplary embodiments provided in the present application, the extruded profile is sequentially subjected to pre-stretch straightening, second sawing, first aging treatment, second aging treatment, and third sawing to obtain the profile sheet.

[0084] The second sawing and the third sawing are performed according to actual application to finally obtain the profile sheet with a required size.

[0085] In the exemplary embodiments provided in the present application, the raw material components of the aluminum alloy are subjected to alloy melting and casting to obtain an alloy ingot rod, including:

[0086] The raw material components of the aluminum alloy are subjected to melting, alloying, and refining to obtain a metal mixed solution, and the metal mixed solution is cast through a semi-continuous casting process at a fourth temperature to obtain an alloy ingot rod.

[0087] The fourth temperature is 730-760 DEG C, at which the molten aluminum can maintain a fluid state to facilitate the semi-continuous casting process; if the fourth temperature is too low, the molten aluminum cannot maintain a fluid state, and if the fourth temperature is too high, the cost will be increased and resources will be wasted; the fourth temperature can also be 735-755 DEG C, and examples are 735 DEG C, 740 DEG C, 745 DEG C, 750 DEG C, and 755 DEG C.

[0088] In the exemplary embodiments provided in the present application, the profile sheet is subjected to oxidation treatment, including:

[0089] End face flattening treatment: flattening the end face of the profiled sheet along the direction perpendicular to the extrusion direction;

[0090] Polishing: polishing the flattened end face;

[0091] Wax removal: removing the wax on the polished end face in an acidic wax removal agent, and then washing with water;

[0092] Oil removal: removing the oil on the wax-removed end face in an acidic oil removal agent, neutralizing at room temperature, and then washing with water;

[0093] Anodic oxidation: anodizing the oil-removed end face using a sulfuric acid solution, and then washing with water;

[0094] Sealing: sealing the anodized end face in a weakly acidic sealing agent, and then washing with water;

[0095] Drying: drying the profiled sheet after sealing in an oven.

[0096] The profiled sheet is subjected to an oxidation treatment to obtain an aluminum alloy with a high-brightness anodic appearance.

[0097] In the example embodiments provided in the present application, as shown in Figure 2 the oxidation treatment of the profiled sheet comprises:

[0098] Step S510: End face flattening treatment: flattening the end face of the profiled sheet along the direction perpendicular to the extrusion direction.

[0099] Step S520: Polishing: polishing the flattened end face.

[0100] The end face of the profiled sheet along the direction perpendicular to the extrusion direction is subjected to flattening treatment, and then polishing, so that the end face is bright and has no obvious visible scratches, facilitating subsequent processing.

[0101] Step S530: Wax removal: removing the wax on the polished end face in an acidic wax removal agent at a fifth temperature for a second time.

[0102] The fifth temperature is 60-80°C, and the acidic medium at this temperature range has the best effect on wax removal of the polished end face; if the temperature is too low, the reaction activity is low, and the wax removal effect is poor; if the temperature is too high, the acidic medium is easy to corrode the aluminum alloy. When the fifth temperature is determined to be 60-80°C, the second time is set to 8-10 minutes, which can not only completely remove the wax on the polished end face, but also will not corrode the aluminum alloy. The fifth temperature can also be 65-75°C, for example, 65°C, 70°C, and 75°C; and the second time can be 8 minutes, 9 minutes, and 10 minutes.

[0103] Step S540: oil removal: the end face after wax removal is subjected to oil removal in an acidic oil removal agent at a sixth temperature for a third time, and then is neutralized with an alkaline solution at room temperature to remove the acidic oil removal agent remaining on the end face after wax removal;

[0104] The sixth temperature is 40-60°C, and the acidic medium at this temperature range has the best effect on oil removal of the end face after wax removal; if the temperature is too low, the reaction activity is low, and the oil removal effect is poor; if the temperature is too high, the acidic medium is easy to corrode the aluminum alloy. When the sixth temperature is determined to be 40-60°C, the third time is set to 4-6 minutes, which can not only more completely remove the oil on the end face after wax removal, but also will not cause corrosion to the aluminum alloy. The sixth temperature can also be 45-55°C, and exemplarily, 45°C, 50°C, or 55°C; and the third time can be 4 minutes, 5 minutes, or 6 minutes.

[0105] Step S550: anodic oxidation: the end face after oil removal is subjected to anodic oxidation using a sulfuric acid solution with a first concentration at an electrode voltage of 14-16V and a temperature of a seventh temperature for a fourth time;

[0106] The seventh temperature is 10-14°C, the first concentration is 190-210g / L, and the fourth time is 40-60 minutes. Under these conditions, anodic oxidation is performed to form an oxide film with a suitable thickness on the end face after oil removal, effectively protect the surface of the aluminum alloy, increase the corrosion resistance and wear resistance of the aluminum alloy, and improve the service life of the aluminum alloy. The seventh temperature can also be 11-13°C, and exemplarily, 11°C, 12°C, or 13°C; the first concentration can also be 195g / L-205g / L, and exemplarily, 195g / L, 200g / L, or 205g / L; and the fourth time can also be 45-55 minutes, and exemplarily, 45 minutes, 50 minutes, or 55 minutes. In the exemplary embodiments provided in the present application, the anodic oxidation is natural anodic oxidation without coloring, and a light-colored (silver-colored) anodic appearance is obtained, which is convenient for verification in the case where appearance defects are most likely to be exposed; in other embodiments, colored anodic oxidation can also be used, and the experimental results of natural anodic oxidation treatment are also applicable to the dark-colored anodic effect after coloring, and have universality.

[0107] Step S560: hole sealing: the end face after anodic oxidation is subjected to hole sealing in a weakly acidic hole sealing agent at an eighth temperature for a fifth time;

[0108] The eighth temperature is 90-95°C, and the fifth time is 30-40 minutes. When the weakly acidic medium at this temperature range is used for hole sealing of the end face after oxidation and the hole sealing time is 30-40 minutes, the permeability of the weakly acidic medium is best, and the hole sealing effect is best. The fifth time can also be 35-40 minutes.

[0109] Step S570: drying: drying the profiled plate after sealing the holes in the oven at 70-80℃, and the drying time is 15-20 minutes.

[0110] In order to more clearly explain the technical solutions of the present application, examples 1-10 of the aluminum alloy of the present application are listed in this paper, in addition, comparative examples 1-4 are also listed in this paper, which are convenient for explaining the technical solutions of the present application. Among them, the aluminum alloy formula of examples 1-10 and comparative examples 1-4 is shown in table 1.

[0111] Table 1 formula of examples 1-10 and comparative examples 1-4

[0112] No. Mg (wt. %) Si (wt. %) Cu (wt. %) Mn (wt. %) Fe (wt. %) Al (wt. %) Example 1 0.89 0.76 0.63 0.1 0.1 Balance Example 2 0.85 0.65 0.9 0.12 0.1 Balance Example 3 0.9 0.69 0.97 0.06 0.09 Balance Example 4 0.85 0.63 0.72 0.2 0.07 Balance Example 5 0.84 0.74 0.75 0.08 0.05 Balance Example 6 0.82 0.67 0.8 0.18 0.08 Balance Example 7 0.88 0.61 0.68 0.12 0.05 Balance Example 8 0.8 0.7 0.7 0.1 0.04 Balance Example 9 0.85 0.73 0.85 0.15 0.09 Balance Example 10 0.9 0.68 0.95 0.05 0.06 Balance Comparative Example 1 0.95 0.6 0.97 0.07 0.1 Balance Comparative Example 2 0.85 0.81 0.95 0.06 0.09 Balance Comparative Example 3 0.89 0.76 0.55 0.1 0.1 Balance Comparative Example 4 0.91 0.61 0.5 0.15 0.1 Balance

[0113] The preparation method of example 1 alloy includes:

[0114] According to the formula of example 1 in table 1, the raw material components of the aluminum alloy are melted, alloyed and refined to obtain a metal mixed solution, and the metal mixed solution is cast by semi-continuous casting process at 760℃ (fourth temperature) to obtain an alloy cast bar.

[0115] First, the alloy cast bar is uniformly annealed by stepwise heating to 560℃ (first temperature) for 12 hours (first time), and then air cooling is adopted to cool the temperature of the alloy cast bar to room temperature, and then first sawing is carried out to obtain a homogenized cast bar;

[0116] The homogenized cast bar is inductively heated to 540℃ (second temperature) for holding, the temperature at the outlet of the extruder is set to 580℃ (third temperature), and the homogenized cast bar is extruded by using the extruder to obtain an extruded profile, and then in-line quenching is carried out; wherein the extrusion ratio is 50, and the extrusion speed is 50mm / s;

[0117] The extruded profile is sequentially subjected to pre-stretching straightening, second sawing, standing at 180℃ for 10 hours, and third sawing to obtain a profiled plate;

[0118] Then take 3 pieces of profiled plate of example 1 for oxidation treatment.

[0119] The oxidation treatment of the profiled plate of example 1 includes:

[0120] End face flattening treatment: flattening the end face of the profiled plate along the vertical extrusion direction;

[0121] Polishing: polishing the flattened end face to a bright surface without obvious visible scratches;

[0122] Wax removal: the end face after polishing and polishing is subjected to wax removal in an acidic wax removal agent at 70°C (fifth temperature), the wax removal time is 8 minutes (second time), then the end face is washed with water to remove the acidic wax removal agent remaining on the end face;

[0123] Oil removal: the end face after wax removal is subjected to oil removal in an acidic oil removal agent at 50°C (sixth temperature), the oil removal time is 4 minutes (third time), the acidic oil removal agent remaining on the end face is neutralized and removed with an alkaline solution at room temperature, and then the end face is washed with water to remove the alkaline solution remaining on the end face;

[0124] Anodic oxidation: the end face after oil removal is subjected to anodic oxidation using a 200 g / L (first concentration) sulfuric acid solution at an electrode voltage of 15 V and a temperature of 12°C (seventh temperature), the oxidation time is 50 minutes (fourth time), an oxide film is formed on the end face after oil removal, and then the end face is washed with water to remove the sulfuric acid solution remaining on the end face;

[0125] Sealing: the end face after anodic oxidation is subjected to sealing in a weakly acidic sealing agent at 95°C (eighth temperature), the sealing time is 30 minutes (fifth time), and then the end face is washed with water to remove the weakly acidic sealing agent remaining on the end face;

[0126] Drying: the profiled sheet after sealing is dried in an oven at 75°C, and the drying time is 15 minutes.

[0127] The alloys of Examples 2-10 and Comparative Examples 1-4 are prepared by using a similar preparation method as that of Example 1, except that the specific parameters in the preparation process are different, the formulations of the alloys of Examples 2-10 and Comparative Examples 1-4 are shown in Table 1, and the specific parameters in the preparation process of the alloys of Examples 2-10 and Comparative Examples 1-4 are shown in Tables 2-3.

[0128] Table 2 Specific parameters in the preparation process of the alloys of Examples 1-10 and Comparative Examples 1-4

[0129] No. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 First temperature (°C) 560 550 565 580 540 570 545 First time (hours) 12 10 11.5 12 14 11 13.5 Second temperature (°C) 540 550 545 535 530 540 535 Third temperature (°C) 570 580 575 585 590 560 565 Fourth temperature (°C) 760 730 750 735 740 760 740 Fifth temperature (°C) 70 65 75 60 70 80 75 Second time (minutes) 8 10 8 9 9 8 10 Sixth temperature (°C) 50 55 40 50 45 40 55 Third time (minutes) 4 6 5 5.5 6 4.5 5 Seventh temperature (°C) 12 10 13 11 14 12 13 First concentration (g / L) 200 190 195 200 195 190 205 Fourth time (minutes) 50 45 50 40 60 50 55 Eighth temperature (°C) 95 93 92 90 93 92 94 Fifth time (minutes) 30 32 40 36 35 35 38

[0130] Table 3 Specific parameters in the preparation process of the alloys of Examples 1-10 and Comparative Examples 1-4 (continued)

[0131]

[0132]

[0133] The alloys of Examples 1-10 and Comparative Examples 1-4 are subjected to mechanical property testing according to GB / T 228.1-2010 "Metallic Materials-Tensile Testing-Part 1: Method of Test at Room Temperature", and the yield strength is used as an indicator, and the test results are shown in Table 4.

[0134] Table 4 Test results of mechanical properties of Examples 1-10 and Comparative Examples 1-4

[0135]

[0136] As can be seen from the performance test results in Table 4, the mechanical properties of the alloys of Examples 1-10 are higher than those of Comparative Examples 3-4, and the mechanical properties of the alloy of Example 3 are particularly outstanding. The main reason for the lower mechanical properties of the alloys of Comparative Examples 3-4 is that the Cu content in the formula is too low. Although the mechanical properties of the alloys of Comparative Examples 1-2 are higher than those of Comparative Examples 3-4, the appearance brightness of the alloys of Comparative Examples 1-2 is not good.

[0137] In addition, the appearance morphology of the end surface of the alloy profile sheet of Examples 1-10 and Comparative Examples 1-2 after anodic oxidation treatment is observed. First, in terms of color, the end surface of Comparative Example 1 alloy after anodic oxidation appears obvious yellowing, while the end surface of Examples 1-3 alloys presents a uniform and delicate silver color, and there is no obvious contrast on a macroscopic scale. The Cu content in Comparative Example 1 is relatively high, and the Mg content is also relatively high, which is the main reason for the yellowing of the surface of the aluminum alloy. The Cu content in Comparative Example 2 is relatively high, and the Si content is also relatively high, which also leads to the phenomenon of yellowing of the surface of the aluminum alloy. However, the high-Cu alloys of Examples 1-3 do not appear yellowing, mainly because the Mg and Si contents are more reasonable than those of Comparative Examples 1-2, and the solid solution of Cu in the Al matrix and the content of Cu-rich phase are different from those of Comparative Examples 1-2. This means that even for high-Cu alloys that pursue high strength, the phenomenon of anodic appearance yellowing can be avoided by adjusting the Mg and Si elements. Second, in terms of brightness, the overall brightness of the end surface of Examples 1-3 alloys is higher than that of Comparative Example 1 alloy. By magnifying the end surface of Example 3 and Comparative Example 1 alloy, it can be found that the brightness of Example 3 alloy is relatively high and transparent, while the end surface of Comparative Example 1 alloy can be observed to have a hazy appearance defect, and the transparency is lower than that of Example 3 alloy. The appearance of Example 1 alloy, Example 2 alloy and Example 3 alloy is similar, and the appearance of Comparative Example 1 alloy is obviously different, which indicates that the higher the Cu content of the alloy, the more sensitive the alloy appearance to the Mg and Si contents. In addition to the Cu solid-solved in the Al matrix, there are still many Cu atoms affecting the formation of Cu-rich phases (such as S phase, θ phase) and β phase precursor phase. The appearance morphology of Examples 4-10 alloys is similar to that of Examples 1-3 alloys, and the alloy appearance is not yellow, the brightness is relatively high and the transparency is high.

[0138] Therefore, when the alloy composition falls within the composition range of Examples 1-10, the alloy not only has certain mechanical properties, but also can ensure to achieve a high-brightness and transparent anodic appearance.

[0139] In summary, in the aluminum alloy formula of the present application, by reasonably adjusting the content of Mg, Si, Cu and Mn elements, and strictly controlling the content of Fe and impurities, the aluminum alloy not only has certain mechanical properties, but also is beneficial to realize high-brightness anode appearance. The present application scientifically and reasonably designs the alloy formula from the source of the alloy. The aluminum alloy prepared by the preparation method of the present application does not appear anode appearance defects such as haze, yellowing, material lines and the like even after oxidation treatment, the color is uniform and delicate, and presents high-brightness, transparent appearance characteristics, and is very suitable for manufacturing appearance structural parts of 3C products.

[0140] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An aluminum alloy, characterized in that, The aluminum alloy comprises the following components by weight percentage: The balance consists of Al and impurities, wherein the impurity content does not exceed 0.1%. The mass percentage ratio C1 = (Mg + Si) / Cu is 1.64 to 1.

67.

2. The aluminum alloy according to claim 1, characterized in that, The mass percentage ratio C2 = Si / Cu is 0.60 to 1.

20.

3. The aluminum alloy according to claim 1, characterized in that, The mass percentage ratio C3 = Mg / Si is 1.05 to 1.

50.

4. The aluminum alloy according to claim 1, characterized in that, The mass percentage ratio C4 = Cu / Mn is 5.00 to 17.

00.

5. A method for preparing an aluminum alloy according to claim 1, characterized in that, include: The raw material components of the aluminum alloy are alloyed and cast to obtain an alloy casting rod; The alloy casting rod is homogenized to obtain a homogenized casting rod; The homogenized casting rod is extruded to obtain an extruded profile; The extruded profile is pre-stretched and straightened, and then aged to obtain a profile sheet. The aluminum alloy is obtained by oxidizing the profile sheet.

6. The preparation method according to claim 5, characterized in that, The process of homogenizing the alloy casting rod to obtain a homogenized casting rod includes: The alloy casting rod is heated to a first temperature according to a preset method and held at that temperature for an immediate time before annealing. Cooling under preset conditions, the alloy casting rod is cooled to room temperature and then cut for the first time to obtain a homogenized casting rod. Wherein, the first temperature is 540-580℃, and the first time is 10-14 hours; The aluminum alloy comprises the following components by weight percentage: The balance consists of Al and impurities; The mass percentage ratio C1 = (Mg + Si) / Cu is 1.64 to 1.

67.

7. The preparation method according to claim 5, characterized in that, The step of extruding the homogenized casting rod to obtain the extruded profile includes: The homogenized casting rod is kept at a second temperature, and the temperature at the extrusion outlet is set as a third temperature. The homogenized casting rod is then extruded to obtain an extruded profile, which is then quenched online. The second temperature is 530–550°C, and the third temperature is 550–570°C.

8. The preparation method according to claim 5, characterized in that, The timeliness processing includes at least one of a first timeliness processing and a second timeliness processing; The first aging treatment process involves standing at 170–185°C for 8–12 hours. The second aging treatment process involves standing at room temperature for 4 to 10 hours.

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