6-series aluminum alloy and preparation method thereof

Abstract

The invention relates to a 6-series aluminum alloy and a preparation method thereof. The 6-series aluminum alloy comprises the following components in percentage by mass: 1.15 to 1.35 percent of Si, 0.30 to 0.50 percent of Cu, 0.30 to 0.60 percent of Mn, 0.90 to 1.30 percent of Mg, 0.15 to 0.20 percent of Cr, less than or equal to 0.20 percent of Zn, 0.05 to 0.15 percent of Ti, 0.05 to 0.10 percent of Zr, less than or equal to 0.15 percent of Fe and the balance of Al. The precipitated phase of the 6-series aluminum alloy comprises Al5Cu2Mg8Si6 and Mg2Si, and the total content of the Al5Cu2Mg8Si6 and the Mg2Si in the 6-series aluminum alloy is 2.18%-3.30% of the mass of the 6-series aluminum alloy. The 6-series aluminum alloy has good anodic oxidation blackening performance and high mechanical strength, defects such as material lines and hard spots are not prone to occurring after anodic oxidation blackening, and the requirements of optical products are met.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and particularly to a 6-series aluminum alloy and a preparation method thereof. Background Art

[0002] 6-series aluminum alloys have characteristics such as low density, good anodic oxidation blackening performance and mechanical properties, and high thermal conductivity, and are widely used in the field of optical products. With the development of the lightness and thinness of optical products, it is required that 6-series aluminum alloys not only have good anodic oxidation blackening performance, but also have higher strength. However, traditional 6-series aluminum alloys (such as material grades 6063 and 6061) have insufficient strength and cannot meet the performance requirements of light and thin products. Therefore, it is urgent to develop a 6-series aluminum alloy that takes into account both anodic oxidation blackening performance and mechanical strength performance.

[0003] It is understood that there are currently two ways to improve the strength of 6-series aluminum alloys. One is to adjust the alloy composition. For example, adding a small amount of Fe element to refine the grains. Although the strength of 6-series aluminum alloys is improved to a certain extent, material streaks appear after anodic oxidation blackening treatment, resulting in non-compliance with the requirements of optical products. The other is to use second-phase strengthening. For example, introducing ceramic particles into 6-series aluminum alloys. Although the strength is significantly improved, the ceramic particles are prone to agglomeration, and defects such as pitting are likely to appear after 6-series aluminum alloys are subjected to anodic oxidation blackening treatment, resulting in the anodic oxidation blackening effect not meeting the requirements of optical products. Obviously, the currently improved 6-series aluminum alloys still cannot achieve the technical effect of taking into account both anodic oxidation blackening performance and mechanical strength performance. Summary of the Invention

[0004] Based on this, in view of the above problems, it is necessary to provide a 6-series aluminum alloy and a preparation method thereof; the 6-series aluminum alloy has both good anodic oxidation blackening performance and high mechanical strength, and is not prone to defects such as material streaks and pitting after anodic oxidation blackening, and can meet the requirements of optical products.

[0005] A 6-series aluminum alloy, the components of the 6-series aluminum alloy include, by mass percentage: Si: 1.15% - 1.35%, Cu: 0.30% - 0.50%, Mn: 0.30% - 0.60%, Mg: 0.90% - 1.30%, Cr: 0.15% - 0.20%, Zn: ≤0.20%, Ti: 0.05% - 0.15%, Zr: 0.05% - 0.10%, Fe: ≤0.15%, and the balance is Al; The precipitation phases of the 6-series aluminum alloy include Al 5 Cu 2 Mg 8 Si 6 and Mg 2 Si, Al 5Cu 2 Mg 8 Si 6 and Mg 2 The total content of Si and Mg in the 6xxx series aluminum alloy is 2.18% - 3.30% of the mass of the 6xxx series aluminum alloy.

[0006] In one embodiment, in the 6xxx series aluminum alloy, Al 5 Cu 2 Mg 8 Si 6 has a content of 1.80% - 2.46%, and Mg 2 Si has a content of 0.30% - 1.20%.

[0007] In one embodiment, in the components of the 6xxx series aluminum alloy, the mass ratio of Mg to Si is (0.73 - 1.10):1.

[0008] In one embodiment, in the components of the 6xxx series aluminum alloy, the mass ratio of the sum of the masses of Mg and Si to Cu is (4.60 - 7.00):1.

[0009] A method for preparing a 6xxx series aluminum alloy as described above, comprising the following steps: Melting and refining aluminum alloy raw materials according to the component formula to make a cast rod; Subjecting the cast rod to homogenization treatment, extrusion treatment, first quenching treatment, heat treatment, and aging treatment in sequence to obtain a 6xxx series aluminum alloy, and the cooling intensity of the first quenching treatment is 110°C / s - 150°C / s.

[0010] In one embodiment, the steps of the homogenization treatment satisfy at least one of the following conditions: (1) The temperature is 540°C - 560°C; (2) The holding time is 8h - 12h.

[0011] In one embodiment, the steps of the extrusion treatment satisfy at least one of the following conditions: (1) The preheating temperature of the cast rod is 510°C - 530°C; (2) The temperature of the extrusion device is 400°C - 520°C; (3) The extrusion speed is 3m / min - 4m / min.

[0012] In one embodiment, the steps of the heat treatment satisfy at least one of the following conditions: (1) The temperature is 540°C - 560°C; (2) The holding time is 1h - 3h.

[0013] In one embodiment, the steps of the aging treatment satisfy at least one of the following conditions: (1) The temperature is 160°C to 190°C; (2) The heating-up time is 1 h to 2 h; (3) The heat preservation time is 8 h to 12 h.

[0014] In one embodiment, after the heat treatment and before the aging treatment, a second quenching treatment is carried out. The transfer time of the second quenching treatment is less than or equal to 10 s, and the cooling intensity of the second quenching treatment is greater than or equal to 100°C / s.

[0015] For the 6xxx series aluminum alloy of the present invention, by regulating the element content, the 6xxx series aluminum alloy has a specific component formula and a precipitated phase Al 5 Cu 2 Mg 8 Si 6 and Mg 2 Si, which can not only achieve the effect of refining grains, effectively improve the mechanical strength, but also avoid defects such as material streaks and pitting caused by blackening during anodic oxidation, and make the anodic oxidation coloring have good uniformity and continuity.

[0016] Therefore, the 6xxx series aluminum alloy provided by the present invention has both good blackening performance during anodic oxidation and relatively high mechanical strength, overcomes the performance defects of traditional 6xxx series aluminum alloys, can meet the requirements of optical products, and especially can meet the performance requirements of thin and light products. Detailed embodiments

[0017] To facilitate the understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the specification of this invention are only for the purpose of describing specific embodiments or examples, and are not intended to limit the invention. In this invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0019] The present invention provides a 6xxx series aluminum alloy. The components of the 6xxx series aluminum alloy by mass percentage include Si: 1.15% - 1.35%, Cu: 0.30% - 0.50%, Mn: 0.30% - 0.60%, Mg: 0.90% - 1.30%, Cr: 0.15% - 0.20%, Zn: ≤0.20%, Ti: 0.05% - 0.15%, Zr: 0.05% - 0.10%, Fe: ≤0.15%, and the balance is Al; the precipitation phases of the 6xxx series aluminum alloy include Al 5 Cu 2 Mg 8 Si 6 and Mg 2 Si, Al 5 Cu 2 Mg 8 Si 6 and Mg 2 The total content of Si in the 6xxx series aluminum alloy is 2.18% - 3.30% of the mass of the 6xxx series aluminum alloy.

[0020] For the 6xxx series aluminum alloy of the present invention, by regulating the element content, the 6xxx series aluminum alloy has a specific component formula and has precipitation phases Al 5 Cu 2 Mg 8 Si 6 and Mg 2 Si. It can not only achieve the effect of grain refinement, effectively improve the mechanical strength, but also avoid defects such as material streaks and pitting during anodic oxidation blackening, making the anodic oxidation coloring have good uniformity and continuity.

[0021] Therefore, the 6xxx series aluminum alloy provided by the present invention has both good anodic oxidation blackening performance and high mechanical strength, overcomes the performance defects of traditional 6xxx series aluminum alloys, can meet the requirements of optical products, and in particular can meet the performance requirements of thin and light products.

[0022] By adjusting the contents of Si element and Mg element in the 6xxx series aluminum alloy, it is beneficial to further promote the formation of Mg 2 Si phase mainly by Si element and Mg element, and avoid defects caused by blackening during anodic oxidation.

[0023] It should be noted that in the 6xxx series aluminum alloy, the mass percentage of Si includes but is not limited to any value among 1.15%, 1.20%, 1.25%, 1.30%, 1.35% or the range value between any two of them; the mass percentage of Mg includes but is not limited to any value among 0.90%, 1.00%, 1.10%, 1.20%, 1.30% or the range value between any two of them.

[0024] In an embodiment of the present invention, in the components of the 6xxx series aluminum alloy, the mass ratio of Mg to Si is preferably (0.73~1.10):1, more preferably (0.77~1.08):1, which is beneficial to avoid reducing the solubility of Mg 2 Si phase in solid aluminum due to excessive Mg element, resulting in problems such as precipitation of strengthening phase from the matrix and appearance of spots after oxidation, thereby further improving the uniformity and continuity of anodic oxidation coloring.

[0025] By adjusting the content of Cu element in the 6xxx series aluminum alloy, it is not only beneficial to significantly improve the mechanical strength of the aluminum alloy, but also the Cu element in the aluminum alloy will disperse and precipitate Al 2 Cu phase and Al 2 CuMg phase after heat treatment, forming a multi-equilibrium phase system in the aluminum alloy, thereby ensuring the anodic oxidation blackening performance.

[0026] It should be noted that in the 6xxx series aluminum alloy, the mass percentage of Cu includes but is not limited to any value among 0.30%, 0.35%, 0.40%, 0.45%, 0.50% or the range value between any two of them.

[0027] Furthermore, by adjusting the mass relationship among Cu, Mg and Si, it is beneficial to further optimize the component formula of the 6xxx series aluminum alloy, so that both the anodic oxidation blackening performance and the mechanical performance reach better effects. Preferably, in the components of the 6xxx series aluminum alloy, the mass ratio of the sum of Mg and Si to Cu is (4.60~7.00):1, more preferably (4.70~6.50):1.

[0028] By adjusting the content of Mn element in the 6xxx series aluminum alloy, it is not only beneficial to further improve the fine grain effect, but also can avoid uneven distribution of Al 6 Mn phase caused by Mn element segregation, resulting in problems such as pitting after anodic oxidation, thereby further improving the uniformity and continuity of anodic oxidation coloring.

[0029] It should be noted that in the 6xxx series aluminum alloy, the mass percentage of Mn includes but is not limited to any value among 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60% or the range value between any two of them, and is preferably 0.30% - 0.50%.

[0030] By regulating the Ti element in the 6xxx series aluminum alloy, it is beneficial to further improve the grain refinement effect, and at the same time avoid the formation of Al-Ti based crystalline products and precipitates, so that the 6xxx series aluminum alloy takes into account both anodic oxidation blackening performance and mechanical strength. As a preference, in the 6xxx series aluminum alloy, the mass percentage of Ti is 0.05% - 0.12%.

[0031] By regulating the content of Zr element in the 6xxx series aluminum alloy, it can inhibit the dynamic recrystallization of the aluminum alloy during extrusion and avoid the formation of Al-Zr based crystalline products and precipitates, so that the 6xxx series aluminum alloy takes into account both anodic oxidation blackening performance and mechanical properties. As a preference, in the 6xxx series aluminum alloy, the mass percentage of Zr is 0.06% - 0.09%.

[0032] By regulating the content of Fe element in the 6xxx series aluminum alloy, it is beneficial to avoid the formation of AlFeSi or AlFeMnSi phases due to excessive consumption of Si element and Mn element by Fe element, thereby further improving the mechanical properties and the uniformity and continuity of oxidation coloring. As a preference, in the 6xxx series aluminum alloy, the mass percentage of Fe is less than or equal to 0.13%.

[0033] By adjusting the Al 5 Cu 2 Mg 8 Si 6 precipitation phase and the mass ratio of the Mg 2 Si precipitation phase, it is not only beneficial to further balance the anodic oxidation blackening performance and mechanical properties, but also beneficial to avoid the appearance of the anodic oxidation film turning yellow due to the formation of red copper oxide during anodic oxidation caused by excessive Cu element, thereby further improving the uniformity of oxidation coloring. It can be understood that in the 6xxx series aluminum alloy, Al 5 Cu 2 Mg 8 Si 6 and the total content of Mg 2 Si includes but is not limited to any value among 2.20%, 2.45%, 2.50%, 2.80%, 3.00%, 3.02%, 3.20%, 3.30% or the range value between any two of them, and is preferably 2.58% - 3.30%.

[0034] In an embodiment of the present invention, in the 6xxx series aluminum alloy, Al5 Cu 2 Mg 8 Si 6 The content of is preferably 1.80% - 2.46%, including but not limited to any value among 1.80%, 1.97%, 2.10%, 2.20%, 2.30%, 2.46% or the range value between any two of them, and more preferably 1.97% - 2.46%; Mg 2 The content of Si is preferably 0.30% - 1.20%, including but not limited to any value among 0.30%, 0.37%, 0.50%, 0.70%, 0.90%, 1.09%, 1.20% or the range value between any two of them, and more preferably 0.37% - 1.09%.

[0035] It can be understood that other precipitation phases may also be contained in the 6 - series aluminum alloy, and the present invention does not limit this.

[0036] The present invention also provides a preparation method of the 6 - series aluminum alloy as described above, including the following steps: S1, melting and refining the aluminum alloy raw materials according to the component formula to make a casting rod; S2, successively performing homogenization treatment, extrusion treatment, first quenching treatment, heat treatment and aging treatment on the casting rod to obtain the 6 - series aluminum alloy, and the cooling intensity of the first quenching treatment is 110℃ / s - 150℃ / s.

[0037] On the basis of controlling the element content, the present invention adjusts the cooling intensity of the first quenching treatment to 110℃ / s - 150℃ / s, which is beneficial to avoiding problems such as coarse - grain defects caused by recrystallization and material streaks in anodic oxidation, so as to ensure that the obtained 6 - series aluminum alloy can take into account good anodic oxidation blackening performance and high mechanical strength.

[0038] In step S1, it can be understood that the component formula includes, by mass percentage, Si: 1.15% - 1.35%, Cu: 0.30% - 0.50%, Mn: 0.30% - 0.60%, Mg: 0.90% - 1.30%, Cr: 0.15% - 0.20%, Zn: ≤0.20%, Ti: 0.05% - 0.15%, Zr: 0.05% - 0.10%, Fe: ≤0.15%, and the balance is Al.

[0039] It should be noted that the present invention does not limit the specific process of melting and refining the aluminum alloy raw materials into a casting rod, and conventional processes can be used. For example: after melting the aluminum alloy raw materials, the casting rod is obtained through processes such as stirring, refining, slag skimming, degassing, filtering, and casting.

[0040] In step S2, homogenization treatment is beneficial to improving the tissue uniformity of the casting rod and reducing the residual internal stress during the continuous casting process.

[0041] In an embodiment of the present invention, the temperature of the homogenization treatment is 540°C to 560°C. By regulating the temperature of the homogenization treatment, it is beneficial to fully dissolve the coarse precipitates inside the casting rod, thereby increasing the degree of residual stress elimination. At the same time, it avoids the melting of the low-melting-point precipitates in the casting rod, thereby reducing the risk of defects such as pores inside the casting rod, and further improving the comprehensive performance of the extruded bar.

[0042] It should be noted that the temperature of the homogenization treatment includes but is not limited to any point value or the range value between any two of 540°C, 545°C, 550°C, 555°C, and 560°C.

[0043] In an embodiment of the present invention, the heat preservation time of the homogenization treatment is 8h to 12h, including but not limited to any point value or the range value between any two of 8h, 9h, 10h, 11h, and 12h.

[0044] In an embodiment of the present invention, in the steps of the extrusion treatment, the preheating temperature of the casting rod is 510°C to 530°C, which is beneficial to reducing the deformation resistance of the casting rod, reducing the difficulty of the extrusion treatment, and at the same time avoiding the melting of the low-melting-point precipitates in the casting rod during the preheating process, thereby reducing the risk of defects such as pores inside the casting rod, and further improving the comprehensive performance of the extruded bar.

[0045] It should be noted that the preheating temperature of the casting rod includes but is not limited to any point value or the range value between any two of 510°C, 515°C, 520°C, 525°C, and 530°C.

[0046] In an embodiment of the present invention, in the steps of the extrusion treatment, the temperature of the extrusion device is 400°C to 520°C. It should be noted that the extrusion device includes an extrusion cylinder and an extrusion die. Preferably, the temperature of the extrusion cylinder is 400°C to 420°C, and the temperature of the extrusion die is 500°C to 520°C.

[0047] In an embodiment of the present invention, in the steps of the extrusion treatment, the extrusion speed is 3m / min to 4m / min, which is beneficial to avoiding problems such as grain coarsening caused by recrystallization, ensuring the high mechanical strength of the aluminum alloy, and at the same time avoiding the reduction of the quality of the aluminum alloy product due to extrusion cracking on the surface of the casting rod.

[0048] It should be noted that the extrusion speed includes but is not limited to any point value or the range value between any two of 3m / min, 3.2m / min, 3.5m / min, 3.8m / min, and 4m / min.

[0049] In an embodiment of the present invention, after the first quenching treatment, the temperature of the cast rod drops to below 50°C.

[0050] In an embodiment of the present invention, the temperature of the heat treatment is 540°C to 560°C, which is beneficial to the full re-dissolution of the precipitated phase, improving the solid solution degree, and thus giving full play to the mechanical strength of the aluminum alloy.

[0051] It should be noted that the temperature of the heat treatment includes but is not limited to any value among 540°C, 545°C, 550°C, 555°C, 560°C or the range value between any two of them.

[0052] In an embodiment of the present invention, the holding time of the heat treatment is 1 h to 3 h, including but not limited to any value among 1 h, 1.5 h, 2 h, 2.5 h, 3 h or the range value between any two of them.

[0053] In an embodiment of the present invention, the temperature of the aging treatment is 160°C to 190°C, which is beneficial to ensuring the full precipitation of the strengthening phase and having a smaller size, thereby further improving the mechanical strength of the aluminum alloy.

[0054] It should be noted that the temperature of the aging treatment includes but is not limited to any value among 160°C, 170°C, 180°C, 190°C or the range value between any two of them.

[0055] In an embodiment of the present invention, the heating-up time of the aging treatment is 1 h to 2 h, including but not limited to any value among 1 h, 1.2 h, 1.5 h, 1.7 h, 2 h or the range value between any two of them.

[0056] In an embodiment of the present invention, the holding time of the aging treatment is 8 h to 12 h, including but not limited to any value among 8 h, 9 h, 10 h, 11 h, 12 h or the range value between any two of them.

[0057] In an embodiment of the present invention, after the heat treatment and before the aging treatment, a second quenching treatment is carried out. The transfer time of the second quenching treatment is less than or equal to 10 s, and the cooling intensity of the second quenching treatment is greater than or equal to 100°C / s. Preferably, the time interval between the second quenching treatment and the aging treatment is less than or equal to 4 h, which is beneficial to improving the solid solution degree, so that the strengthening phase can be fully precipitated in the subsequent aging treatment step, and further improving the mechanical strength of the aluminum alloy.

[0058] Hereinafter, the 6000 series aluminum alloy and its preparation method will be further described through the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0059] Example 1 According to the component formula: Si is 1.15%, Cu is 0.40%, Mn is 0.45%, Mg is 1.00%, Cr is 0.15%, Zn is 0.10%, Ti is 0.10%, Zr is 0.07%, Fe is 0.13%, and the balance is Al. The raw materials are melted, and then processed through processes such as stirring, refining, slag skimming, degassing, filtering, and casting to obtain a casting rod.

[0060] The casting rod is subjected to homogenization treatment at a homogenization temperature of 560 °C for 8 hours; the homogenized casting rod is preheated to 510 °C, and then placed in an extruder for extrusion. The temperature of the extrusion cylinder is 420 °C, the temperature of the extrusion die is 500 °C, and the extrusion speed of the product is set at 4 m / min; after the casting rod is extruded, it is cooled to below 50 °C by the first quenching, and the cooling intensity is 130 °C / s; the cooled casting rod is heat-treated, held at 560 °C for 2 hours, and then subjected to the second quenching in water. The quenching transfer time is 10 s, and the cooling intensity is 150 °C / s; immediately after the second quenching, aging treatment is carried out, heating to 170 °C in 2 hours and holding for 10 hours to obtain the 6000 series aluminum alloy.

[0061] Example 2 According to the component formula: Si is 1.25%, Cu is 0.45%, Mn is 0.50%, Mg is 1.30%, Cr is 0.15%, Zn is 0.10%, Ti is 0.10%, Zr is 0.07%, Fe is 0.13%, and the balance is Al. The raw materials are melted, and then processed through processes such as stirring, refining, slag skimming, degassing, filtering, and casting to obtain a casting rod.

[0062] The casting rod is subjected to homogenization treatment at a homogenization temperature of 540 °C for 12 hours; the homogenized casting rod is preheated to 530 °C, and then placed in an extruder for extrusion. The temperature of the extrusion cylinder is 420 °C, the temperature of the extrusion die is 500 °C, and the extrusion speed of the product is set at 3 m / min; after the casting rod is extruded, it is cooled to below 50 °C by the first quenching, and the cooling intensity is 110 °C / s; the cooled casting rod is heat-treated, held at 540 °C for 2 hours, and then subjected to the second quenching in water. The quenching transfer time is 10 s, and the cooling intensity is 120 °C / s; immediately after the second quenching, aging treatment is carried out, heating to 170 °C in 2 hours and holding for 10 hours to obtain the 6000 series aluminum alloy.

[0063] Example 3 According to the component formula: Si is 1.23%, Cu is 0.42%, Mn is 0.50%, Mg is 1.20%, Cr is 0.15%, Zn is 0.10%, Ti is 0.10%, Zr is 0.07%, Fe is 0.13%, and the balance is Al. The raw materials are melted, and then after processes such as stirring, refining, slag skimming, degassing, filtering, and casting, a cast rod is obtained.

[0064] The cast rod is subjected to homogenization treatment at a homogenization temperature of 550 °C for 12 h; the homogenized cast rod is preheated to 520 °C, and then placed in an extruder for extrusion. The extrusion barrel temperature is 420 °C, the extrusion die temperature is 500 °C, and the product extrusion speed is set at 3 m / min; after the cast rod is extruded, it is cooled to below 50 °C by the first quenching, and the cooling intensity is 110 °C / s; the cooled cast rod is heat-treated, held at 550 °C for 2 h, and then subjected to the second quenching in water. The quenching transfer time is 10 s, and the cooling intensity is 150 °C / s; immediately after the second quenching, aging treatment is carried out, heating 170 °C in 2 h and holding for 10 h to obtain a 6-series aluminum alloy.

[0065] Example 4 According to the component formula: Si is 1.30%, Cu is 0.50%, Mn is 0.50%, Mg is 1.30%, Cr is 0.18%, Zn is 0.10%, Ti is 0.05%, Zr is 0.09%, Fe is 0.13%, and the balance is Al. The raw materials are melted, and then after processes such as stirring, refining, slag skimming, degassing, filtering, and casting, a cast rod is obtained.

[0066] The cast rod is subjected to homogenization treatment at a homogenization temperature of 540 °C for 12 h; the homogenized cast rod is preheated to 530 °C, and then placed in an extruder for extrusion. The extrusion barrel temperature is 400 °C, the extrusion die temperature is 520 °C, and the product extrusion speed is set at 3 m / min; after the cast rod is extruded, it is cooled to below 50 °C by the first quenching, and the cooling intensity is 110 °C / s; the cooled cast rod is heat-treated, held at 540 °C for 2 h, and then subjected to the second quenching in water. The quenching transfer time is 9 s, and the cooling intensity is 120 °C / s; immediately after the second quenching, aging treatment is carried out, heating 160 °C in 2 h and holding for 12 h to obtain a 6-series aluminum alloy.

[0067] Example 5 The difference between Example 5 and Example 2 is that Cu is adjusted to 0.3%, and the balance of Al is adjusted accordingly, while the formula of the other elements remains unchanged.

[0068] Example 6 Example 6 is different from Example 2 in that Mg is adjusted to 0.9%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0069] Example 7 Example 7 is different from Example 2 in that Si is adjusted to 1.15%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0070] Example 8 Example 8 is different from Example 2 in that Si is adjusted to 1.15%, Mg is adjusted to 0.90%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0071] Comparative Example 1 Comparative Example 1 is different from Example 1 in that Si is adjusted to 0.80% and Mg is adjusted to 0.80%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0072] Comparative Example 2 Comparative Example 2 is different from Example 1 in that Cu is adjusted to 0.80%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0073] Comparative Example 3 Comparative Example 3 is different from Example 1 in that Ti is adjusted to 0.30%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0074] Comparative Example 4 Comparative Example 4 is different from Example 1 in that Zr is adjusted to 0.30%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0075] Comparative Example 5 Comparative Example 5 is different from Example 1 in that Fe is adjusted to 0.30%, and the balance of Al is adjusted accordingly, while the formulations of the other elements remain unchanged.

[0076] The 6xxx series aluminum alloys prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were characterized, and the results are shown in Table 1.

[0077] Table 1 The 6xxx series aluminum alloys prepared in all examples and comparative examples, as well as commercial conventional 6061 aluminum alloy, were evaluated for mechanical strength and anodic oxidation blackening performance. The results are shown in Table 2. Among them, the evaluation criteria for anodic oxidation blackening performance are as follows: mainly by visual inspection, requiring uniform blackening oxidation effect on the bar, no blocky mottles, no material texture, no pitting, and no color difference.

[0078] Table 2 As can be seen from Table 1 and Table 2, the 6-series aluminum alloy provided by the present invention has both good anodic oxidation blackening performance and high mechanical strength, and is not prone to defects such as material streaks and pitting after anodic oxidation blackening, which can meet the requirements of optical products.

[0079] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0080] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A 6 series aluminum alloy, characterized in that: The components of the 6 series aluminum alloy include Si: 1.15%~1.35%, Cu: 0.30%~0.50%, Mn: 0.30%~0.60%, Mg: 0.90%~1.30%, Cr: 0.15%~0.20%, Zn: ≤0.20%, Ti: 0.05%~0.15%, Zr: 0.05%~0.10%, Fe: ≤0.15%, and the balance is Al; The precipitated phases of the 6-series aluminum alloy include Al5Cu2Mg8Si6 and Mg2Si, and the total content of Al5Cu2Mg8Si6 and Mg2Si in the 6-series aluminum alloy is 2.18% to 3.30% of the mass of the 6-series aluminum alloy.

2. The 6 series aluminum alloy according to claim 1, characterized in that: In the 6 series aluminum alloy, the content of Al5Cu2Mg8Si6 is 1.80%~2.46%, and the content of Mg2Si is 0.30%~1.20%.

3. The 6 series aluminum alloy according to claim 1, characterized in that: In the composition of the 6 series aluminum alloy, the mass ratio of Mg to Si is (0.73~1.10):

1.

4. The 6 series aluminum alloy according to claim 1 or claim 3, characterized in that: In the composition of the 6-series aluminum alloy, the mass ratio of the sum of the masses of Mg and Si to Cu is (4.60-7.00):

1.

5. A method for preparing a 6 series aluminum alloy according to any one of claims 1 to 4, characterized in that: The steps include: The aluminum alloy raw materials are melted and refined according to the component formula to form cast bars; The cast rod is sequentially subjected to homogenization treatment, extrusion treatment, first quenching treatment, heat treatment and aging treatment to obtain a 6 series aluminum alloy, wherein the cooling intensity of the first quenching treatment is 110°C / s to 150°C / s.

6. The method for preparing a 6 series aluminum alloy according to claim 5, characterized in that: The homogenization step satisfies at least one of the following conditions: (1) Temperature is 540℃~560℃; (2) The insulation time is 8h~12h.

7. The method for preparing a 6-series aluminum alloy according to claim 5, characterized in that: The step of extrusion treatment satisfies at least one of the following conditions: (1) The preheating temperature of the cast rod is 510℃~530℃; (2) The temperature of the extrusion device is 400℃~520℃; (3) The extrusion speed is 3m / min~4m / min.

8. The method for preparing a 6 series aluminum alloy according to claim 5, characterized in that: The heat treatment step satisfies at least one of the following conditions: (1) Temperature is 540℃~560℃; (2) The insulation time is 1h~3h.

9. The method for preparing a 6 series aluminum alloy according to claim 5, characterized in that: The aging treatment step satisfies at least one of the following conditions: (1) Temperature is 160℃~190℃; (2) Heating time is 1h~2h; (3) The insulation time is 8h~12h.

10. The method for preparing a 6 series aluminum alloy according to claim 5, characterized in that: After the heat treatment and before the aging treatment, a second quenching treatment is performed, the transfer time of the second quenching treatment is less than or equal to 10s, and the cooling intensity of the second quenching treatment is greater than or equal to 100°C / s.

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