Al-Mg-Si-Cu alloy and preparation method and application thereof

Abstract

The invention belongs to the technical field of alloys, and particularly relates to an Al-Mg-Si-Cu alloy and a preparation method and application thereof, and the alloy comprises the following components in percentage by mass: 1.5%-2.8% of Mg, 1.0%-1.8% of Si, 0.3%-0.7% of Cu, 0.3%-0.6% of Mn, 0.2%-0.5% of Cr, 0.02%-0.04% of Ti, 0.05%-0.1% of Sc, 0.1%-0.5% of Zn, less than or equal to 0.12% of Fe and 93%-96.53% of Al. According to the aluminum alloy, by adjusting the content of main elements and microalloying elements of the alloy, formation of a coarse strengthening phase is avoided, so that the aluminum alloy material has high strength, high plasticity, a high anodic oxidation effect, good corrosion resistance and high glossiness, and the service life of the aluminum alloy material is prolonged. The invention is used in common parts in the air-conditioning refrigeration industry, such as nuts, valve cores, pipe joints and the like.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, and specifically relates to an Al-Mg-Si-Cu alloy, its preparation method, and its application. Background Technology

[0002] Copper and copper alloys possess excellent electrical and thermal conductivity, making them widely used in heat exchange applications such as air conditioning and refrigeration, including brass nuts, valve cores, and pipe fittings. However, my country faces a severe shortage of copper resources, with insufficient copper ore reserves and persistently high copper prices, necessitating the search for copper substitutes. Aluminum, due to its relatively low price and excellent thermal conductivity, corrosion resistance, and machinability, is the preferred alternative to copper.

[0003] Traditional 6xxx series aluminum alloys offer good anodizing performance, but their tensile strength in the T6 condition generally does not exceed 300 MPa, far lower than that of brass alloys. In the air conditioning and refrigeration industry, to replace brass alloy nuts, valve cores, pipe fittings, and other products, it is necessary to further improve the strength of 6xxx series aluminum alloys by increasing their alloying level. However, with the increase of alloying element content, the anodizing effect and corrosion resistance of 6xxx series aluminum alloys often decrease, failing to meet the appearance and corrosion resistance requirements of nuts, valve cores, pipe fittings, and other products in the air conditioning and refrigeration industry. Summary of the Invention

[0004] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide an aluminum alloy.

[0005] The second objective of this invention is to provide a method for preparing aluminum alloys.

[0006] The third objective of this invention is to provide an air conditioning refrigeration device.

[0007] The fourth objective of this invention is to provide an application of aluminum alloy in the field of heat exchange.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides an aluminum alloy comprising the following components in weight percentages: Mg 1.5~2.8%, Si 1.0~1.8%, Cu 0.3~0.7%, Mn 0.3~0.6%, Cr 0.2~0.5%, Ti 0.02~0.04%, Sc 0.05~0.1%, Zn 0.1~0.5%, Fe≤0.12%, and Al 93%~96.53%.

[0009] In some embodiments of the present invention, the aluminum alloy also contains unavoidable impurities, the total mass percentage of which is ≤0.12%; and the content of each impurity is ≤0.03%.

[0010] In some embodiments of the present invention, the aluminum alloy is composed of the following components in mass percentage: Mg 1.5~2.8%, Si 1.0~1.8%, Cu 0.3~0.7%, Mn 0.3~0.6%, Cr 0.2~0.5%, Ti 0.02~0.04%, Sc 0.05~0.1%, Zn 0.1~0.5%, Fe ≤0.12%, total impurities ≤0.12%, the content of each impurity ≤0.03%, and Al as the balance.

[0011] In some embodiments of the present invention, the mass percentage of Mg is any value or a range formed by any two of the following: 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, and 2.8%.

[0012] In some embodiments of the present invention, the mass percentage of Si is any value or a range formed by any two of 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, and 1.8%.

[0013] In some embodiments of the present invention, the mass percentage of Cu is any one of 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or a range formed by any two of these values.

[0014] In some embodiments of the present invention, the mass percentage of Mn is any value of 0.3%, 0.4%, 0.5%, 0.6%, or a range formed by any two of these values.

[0015] In some embodiments of the present invention, the mass percentage of Cr is any value of 0.2%, 0.3%, 0.4%, 0.5%, or a range formed by any two of these values.

[0016] In some embodiments of the present invention, the mass percentage of Ti is any value of 0.02%, 0.03%, 0.04%, or a range formed by any two of them.

[0017] In some embodiments of the present invention, the mass percentage of Sc is any value of 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, or a range formed by any two of these values.

[0018] In some embodiments of the present invention, the mass percentage of Zn is any value of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range formed by any two of these values.

[0019] In some embodiments of the present invention, the mass percentage of Fe is any value or a range formed by any combination of 0%, 0.01%, 0.03%, 0.05%, 0.07%, 0.09%, 0.1%, 0.11%, and 0.12%.

[0020] In some embodiments of the present invention, the mass ratio of Mg to Si is (1.8~2.2):1; in some embodiments of the present invention, the mass ratio of Mg to Si is any value of 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1 or a range formed by any two of them.

[0021] In some embodiments of the present invention, the total mass percentage of Mg and Si is 2.8 to 4%; in some embodiments of the present invention, the total mass percentage of Mg and Si is any value or a range formed by any two of 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, and 4.0%.

[0022] Compared to existing 6xxx series aluminum alloys, the aluminum alloy in this invention has a higher Mg and Si content, which together form Mg2Si compounds. Mg2Si plays a strengthening role in the material, but excessive or coarse Mg2Si will affect the brightness after anodizing. Therefore, by controlling the Mg and Si content within the range defined in this invention, excellent anodizing effect and superior mechanical properties can be achieved.

[0023] Furthermore, in this invention, a portion of Mg forms a dispersed T phase with Zn and Al, namely Mg 32 (Al,Zn) 49 Compounds. If the Zn content is too low or the Mg content is too high, coarse compounds such as Al3Mg2 will form, affecting mechanical properties, corrosion resistance, and the gloss after anodizing. Cu reacts with Al to form CuAl2 compounds. Mn forms AlFeMnCrSi compounds, which are beneficial for improving the strength, toughness, and corrosion resistance of the alloy; however, excessive Mn can affect quenching sensitivity. Ti and Sc are microalloying elements, playing a role in refining grain size and microstructure. Therefore, this invention, by precisely controlling the content of each component, enables the aluminum alloy to possess excellent anodizing effect, superior mechanical properties, and superior corrosion resistance.

[0024] The second aspect of the present invention provides a method for preparing the aluminum alloy described in the first aspect of the present invention, comprising the following steps: The raw materials are melted and then cast to obtain aluminum alloy castings. The aluminum alloy casting is subjected to homogenization heat treatment, then extruded and formed, and then subjected to T6 heat treatment to obtain the aluminum alloy.

[0025] In some embodiments of the present invention, the casting process is carried out using a vertical semi-continuous casting method.

[0026] In some embodiments of the present invention, the step of melting and casting the raw materials specifically involves melting the raw materials, then refining and removing slag, and after settling, casting the aluminum alloy castings using a vertical semi-continuous method.

[0027] In some embodiments of the present invention, the homogenization heat treatment step is as follows: first, hold at a first homogenization temperature of 300~350℃ for 6h~10h, then raise the temperature to a second homogenization temperature of 520~580℃ and hold for 6~10h, and then cool down.

[0028] In some embodiments of the present invention, the cooling in the homogenization heat treatment step is achieved by using strong air cooling to reduce the temperature to 20~40°C.

[0029] In some embodiments of the present invention, the first homogenization temperature is any value of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or a range formed by any two of them.

[0030] In some embodiments of the present invention, the holding time at the first homogenization temperature is any value of 6h, 7h, 8h, 9h, 10h or a range formed by any two of them.

[0031] In some embodiments of the present invention, the second homogenization temperature is any value of 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, or a range formed by any two of them.

[0032] In some embodiments of the present invention, the holding time at the second homogenization temperature is any value of 6h, 7h, 8h, 9h, 10h or a range formed by any two of them.

[0033] In some embodiments of the present invention, the extrusion molding temperature is 520~570°C; in some embodiments of the present invention, the extrusion molding temperature is any value of 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, or a range formed by any two of them.

[0034] In some embodiments of the present invention, the extrusion speed is 3 to 5 min / min; in some embodiments of the present invention, the extrusion speed is any value of 3 min / min, 4 min / min, 5 min / min, or a range formed by any two of them.

[0035] In some embodiments of the present invention, the extrusion ratio (the extrusion ratio refers to the ratio of the cross-sectional area of ​​the extrusion cylinder cavity to the total cross-sectional area of ​​the extruded product) is (10~25):1; in some embodiments of the present invention, the extrusion ratio is any value of 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1 or a range formed by any two of them.

[0036] In some embodiments of the present invention, the T6 heat treatment is performed by first performing a solution treatment and then an aging treatment.

[0037] In some embodiments of the present invention, the solution treatment is as follows: first, the solution is kept at a first solution temperature of 300~350℃ for 4~6 hours, then the temperature is raised to a second solution temperature of 560~580℃ and kept at that temperature for 6~8 hours, then cooled to 200~300℃ by strong wind or water mist, and then cooled in the air.

[0038] In some embodiments of the present invention, the first solution temperature is any value of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or a range formed by any two of them.

[0039] In some embodiments of the present invention, the holding time at the first solution temperature is any value of 4h, 5h, 6h or a range formed by any two of them.

[0040] In some embodiments of the present invention, the second solution temperature is any value of 560°C, 570°C, 580°C, or a range formed by any two of them.

[0041] In some embodiments of the present invention, the holding time at the second solution temperature is any value of 6h, 7h, 8h or a range formed by any two of them.

[0042] In some embodiments of the present invention, the temperature of the profile after being cooled by strong wind or water mist is any value or a range formed by any two of the following: 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, and 300°C.

[0043] In some embodiments of the present invention, the aging process is as follows: holding at a temperature of 160~180°C for 8~15 hours, and then cooling in air.

[0044] In some embodiments of the present invention, the aging temperature is any value of 160°C, 170°C, 180°C, or a range formed by any two of them.

[0045] In some embodiments of the present invention, the heat preservation time is any value of 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h or a range formed by any two of them.

[0046] A third aspect of the present invention provides an air conditioning refrigeration device, comprising the aluminum alloy described in the first aspect of the present invention or a component formed from the aluminum alloy described in the first aspect of the present invention.

[0047] The fourth aspect of the present invention provides the application of the aluminum alloy described in the first aspect of the present invention in the field of heat exchange.

[0048] The beneficial effects of this invention are: by adjusting the content of the main alloying elements and microalloying elements, the aluminum alloy prepared in this invention avoids the formation of coarse strengthening phases, and the extruded aluminum alloy has a large number of nanoscale second phases uniformly distributed in its microstructure, with a length ≤250nm and a number density of (1~10)×10⁻⁶. -3 nm -3 This significantly improves the mechanical properties of aluminum alloys, giving them high strength, high plasticity, excellent anodizing effect, good corrosion resistance, and high gloss. It can replace brass alloys and be used in commonly used parts in the air conditioning and refrigeration industry, such as nuts, valve cores, and pipe fittings. Attached Figure Description

[0049] Figure 1 This is a 20,000x magnified SEM image of the Al-Mg-Si-Cu alloy profile from Example 1.

[0050] Figure 2 This is a 10,000x magnified SEM image of the Al-Mg-Si-Cu alloy profile in Comparative Example 3.

[0051] Figure 3 This is a 2000x magnified SEM image of the Al-Mg-Si-Cu alloy profile in Comparative Example 7.

[0052] Figure 4 This is a photograph of the aluminum alloy profile after salt spray testing in Example 1.

[0053] Figure 5 This is a photograph of the aluminum alloy profile in Comparative Example 1 after a salt spray test. Detailed Implementation

[0054] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0055] The raw material information used in the following examples and comparative examples is as follows: The mass percentage of Si in the AlSi20 master alloy is 20%, and the mass percentage of Al is 80%. The mass percentage of Mn in the AlMn10 master alloy is 10%, and the mass percentage of Al is 90%. The AlCu50 master alloy contains 50% Cu by mass and 50% Al by mass. The AlCr10 master alloy contains 10% Cr by mass and 90% Al by mass. In Al5Ti0.2B, the mass percentage of Al is 94.8%, the mass percentage of Ti is 5%, and the mass percentage of B is 0.2%. In AlSc10, the mass percentage of Sc is 10% and the mass percentage of Al is 90%.

[0056] Example 1 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 2.1%, Si: 1.3%, Cu: 0.5%, Mn: 0.45%, Cr: 0.35%, Ti: 0.03%, Sc: 0.075%, Zn: 0.3%, Fe: 0.11%, with each other impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0057] The Al-Mg-Si-Cu alloy in this example is prepared using a method that includes the following steps: (1) According to the composition ratio, aluminum ingots with a purity of 99.85%, AlSi20 master alloy, AlMn10 master alloy, AlCu50 master alloy, and AlCr10 master alloy were added to the melting furnace for melting. When the melt temperature reached 740℃, pure Mg ingots and pure Zn ingots were added. After all melts were added, Al5Ti0.2B and AlSc10 were added. The melt was then stirred evenly and refined using high-purity nitrogen and commercially available aluminum alloy refining agent. After refining, the slag was removed, and the melt was allowed to stand for 30 minutes before semi-continuous casting was started. The specific casting process was as follows: the melt temperature was 730℃, the cooling water pressure was 110kPa, the cooling water temperature was 20℃, the casting speed was 140mm / min, and a casting rod with a diameter of 127mm was obtained.

[0058] (2) The casting rod prepared in step (1) is subjected to homogenization heat treatment. The specific process is as follows: keep it at 325℃ for 8 hours, then raise the temperature to 560℃ and keep it at 8 hours, and then cool it down to room temperature by strong air cooling.

[0059] (3) Cut the cast rod prepared in step (2) into extrusion billets, heat the billets to 550°C in an induction heating furnace, and extrude them into solid rod-shaped profiles at an extrusion speed of 4 m / min and an extrusion ratio (the extrusion ratio refers to the ratio of the cross-sectional area of ​​the extrusion cylinder cavity to the total cross-sectional area of ​​the extruded product) of 20:1.

[0060] (4) The profile obtained in step (3) is subjected to T6 heat treatment, wherein the temperature is held at 325℃ for 5 hours, then heated to 570℃ and held for 7 hours, and then cooled by strong air to 250℃ and air-cooled. The aging process is as follows: the aging temperature is 170℃, the holding time is 10 hours, and then the profile is air-cooled to obtain the Al-Mg-Si-Cu alloy in this example.

[0061] Example 2 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 2.8%, Si: 1.7%, Cu: 0.5%, Mn: 0.6%, Cr: 0.35%, Ti: 0.03%, Sc: 0.05%, Zn: 0.3%, Fe: 0.11%, with each other impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0062] The Al-Mg-Si-Cu alloy in this example can be prepared by referring to the preparation method in Example 1.

[0063] Example 3 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 1.5%, Si: 1.0%, Cu: 0.5%, Mn: 0.6%, Cr: 0.35%, Ti: 0.03%, Sc: 0.1%, Zn: 0.3%, Fe: 0.11%, with each other impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0064] Comparative Example 1 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 2.8%, Si: 0.8%, Cu: 0.5%, Mn: 0.6%, Cr: 0.35%, Ti: 0.03%, Sc: 0.05%, Zn: 0.3%, Fe: 0.11%, with each impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0065] Comparative Example 2 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 2.8%, Si: 1.9%, Cu: 0.5%, Mn: 0.6%, Cr: 0.35%, Ti: 0.03%, Sc: 0.05%, Zn: 0.3%, Fe: 0.11wt%, with each impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0066] Comparative Example 3 This example provides an Al-Mg-Si-Cu alloy composed of the following components by mass percentage: Mg: 1.5%, Si: 0.8%, Cu: 0.5%, Mn: 0.6%, Cr: 0.35%, Ti: 0.03%, Sc: 0.1%, Zn: 0.3%, Fe: 0.11wt%, with each impurity content ≤0.03%, the total impurity content ≤0.12%, and the balance being Al.

[0067] Comparative Example 4 The Al-Mg-Si-Cu alloy in this example is the same as that in Example 1.

[0068] The only difference between the preparation method of Al-Mg-Si-Cu alloy in this example and that in Example 1 is that step (2) in this example is to perform a single-stage homogenization heat treatment on the casting rod, specifically by holding it at 490℃ for 16 hours.

[0069] Comparative Example 5 The Al-Mg-Si-Cu alloy in this example is the same as that in Example 1.

[0070] The only difference between the preparation method of Al-Mg-Si-Cu alloy in this example and that in Example 1 is that step (2) in this example is to perform a single-stage homogenization heat treatment on the casting rod, specifically by holding it at 560℃ for 16 hours.

[0071] Comparative Example 6 The Al-Mg-Si-Cu alloy in this example is the same as that in Example 1.

[0072] The only difference between the preparation method of Al-Mg-Si-Cu alloy in this example and that in Example 1 is that step (2) in this example is to perform a single-stage homogenization heat treatment on the casting rod, specifically by holding it at 350℃ for 16 hours.

[0073] Comparative Example 7 The Al-Mg-Si-Cu alloy in this example is the same as that in Example 1.

[0074] The only difference between the preparation method of the Al-Mg-Si-Cu alloy in this example and that in Example 1 is that in step (3) of this example, the ingot temperature is 580℃, the extrusion speed is 5min / min, and the extrusion ratio is 20:1.

[0075] Comparative Example 8 The Al-Mg-Si-Cu alloy in this example is the same as that in Example 1.

[0076] The only difference between the preparation method of the Al-Mg-Si-Cu alloy in this example and that in Example 1 is that in step (3) of this example, the ingot temperature is 510℃, the extrusion speed is 3min / min, and the extrusion ratio is 20:1.

[0077] Comparative Example 9 The aluminum alloy in this example is composed of the following components by mass percentage: Mg 1.6%, Si 1.7%, Mn 0.8%, Cu 0.25%, Zn 0.6%, Fe 0.2%, Cr 0.14%, other alloying elements 0.2%, and the balance being Al. The other alloying elements include a combination of Ni, V, Ti, Zr, and rare earth elements, with a mass ratio of Ni:1.7:0.5:1.5:0.2. The rare earth elements are composed of the following components by mass percentage: Gd 70%, La 20%, and Eu 10%.

[0078] Performance testing: The surface morphology of the Al-Mg-Si-Cu alloy profiles in Example 1, Comparative Example 3, and Comparative Example 7 was tested using scanning electron microscopy. The specific test results are as follows: Figures 1-3 As shown, where, Figure 1The SEM image of the Al-Mg-Si-Cu alloy profile in Example 1, magnified 20,000 times, shows that a large number of nanoscale second phases precipitated within the microstructure, with lengths ≤250 nm and a number density reaching (1~10)×10⁻⁶. -3 nm -3 Furthermore, the second phase is uniformly distributed within the tissue, and tests showed that the precipitated phases in the tissues of Examples 2 and 3 are also nanoscale. Figure 2 The SEM image of the Al-Mg-Si-Cu alloy profile in Comparative Example 3, magnified 10,000 times, shows that the precipitated phases in the microstructure are on the micrometer scale. Figure 3 The SEM image of the Al-Mg-Si-Cu alloy profile in Comparative Example 7, magnified 2000 times, shows that the precipitated phases in the microstructure are on the micrometer scale.

[0079] Samples were taken from the Al-Mg-Si-Cu alloys prepared in Examples 1-3 and Comparative Examples 1-8 for room temperature mechanical property testing. The mechanical properties of the products were tested in accordance with GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Room temperature test method". The specific test results are shown in Table 1 below.

[0080] Table 1 Room temperature mechanical properties of Al-Mg-Si-Cu alloys

[0081] As shown in Table 1, compared with Comparative Examples 1 to 8, the tensile strength, yield strength and elongation of the aluminum alloys in Examples 1 to 3 of this application are significantly improved, specifically the tensile strength is 403 to 457 MPa, the yield strength is 374 to 423 MPa and the elongation is 12.8 to 14.6%.

[0082] Samples were taken from 6061 aluminum alloy profiles, and aluminum alloy profiles from Examples 1-3 and Comparative Examples 1-9. A 24-hour neutral salt spray test was conducted according to GB / T10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test". The actual images of the aluminum alloy profiles from Example 1 and Comparative Example 1 after the test are shown below. Figure 4 and Figure 5 As shown. By Figures 4-5 As can be seen, the surface corrosion of the aluminum alloy profile in Example 1 is very slight and almost unobservable, while the aluminum alloy profile in Comparative Example 1 shows obvious corrosion marks and has poor corrosion resistance. The degree of corrosion of the test samples was rated and judged, and the specific test results are shown in Table 2.

[0083] Table 2. Neutral Salt Spray Test Rating Results

[0084] As shown in Table 2, compared with the aluminum alloys and 6061 aluminum alloy profiles in Comparative Examples 1-9, the aluminum alloys in Examples 1-3 of the present invention significantly improve the salt spray corrosion resistance of the aluminum alloys by adjusting the composition and preparation method of the aluminum alloys.

[0085] Anodizing treatment was performed on 6061 aluminum alloy profiles, aluminum alloy profiles of Examples 1-3 and Comparative Examples 1-9. The specific anodizing process was as follows: the aluminum alloy profiles were first pickled, and then anodized in a sulfuric acid-alumina electrolyte (sulfuric acid concentration of 190 g / L, Al...). 3+ The concentration was 15 g / L, the oxidation tank temperature was 25℃, and the current density was 2.0 A / dm³. 2 Anodizing was performed for 30 minutes. The anodizing effect was evaluated by visual observation and in accordance with GB / T 9754-2007 "Determination of 20°, 60° and 85° specular gloss of paint films without metallic pigments". The specific test results are shown in Table 3.

[0086] Table 3 Evaluation of Anodizing Effect

[0087] As shown in Table 3, the aluminum alloy profiles in Examples 1-3 of this invention, after anodizing, have a good surface with obvious brightness and metallic luster, with a gloss level between 110 and 117 GU, demonstrating a good anodizing effect. In contrast, the aluminum alloy profiles and 6061 aluminum alloy profiles in Comparative Examples 1-9, after anodizing, have no metallic luster and a hazy surface, with a gloss level between 70 and 85 GU.

[0088] 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 by: The aluminum alloy comprises the following components in the following mass percentages: Mg 1.5-2.8%, Si 1.0-1.8%, Cu 0.3-0.7%, Mn 0.3-0.6%, Cr 0.2-0.5%, Ti 0.02-0.04%, Sc 0.05-0.1%, Zn 0.1-0.5%, Fe≤0.12%, and Al 93%-96.53%.

2. The aluminum alloy of claim 1, wherein: The aluminum alloy further comprises inevitable impurities, and the total mass percentage of the impurities is ≤0.12%, and the content of each impurity is ≤0.03%.

3. The aluminum alloy of claim 1, wherein: The aluminum alloy is composed of the following components in the following mass percentages: Mg 1.5-2.8%, Si 1.0-1.8%, Cu 0.3-0.7%, Mn 0.3-0.6%, Cr 0.2-0.5%, Ti 0.02-0.04%, Sc 0.05-0.1%, Zn 0.1-0.5%, Fe≤0.12%, total impurities ≤0.12%, and the content of each impurity is ≤0.03%, and Al is the balance.

4. The aluminum alloy of any of claims 1-3, wherein: The mass ratio of Mg to Si is (1.8-2.2):

1. And / or, the total mass percentage of Mg and Si is 2.8-4%.

5. A method of producing the aluminum alloy according to any one of claims 1 to 4, characterized by: The method comprises the following steps: After melting the raw materials, the aluminum alloy castings are obtained by casting forming; The aluminum alloy castings are subjected to homogenization heat treatment, then extrusion forming, and then T6 heat treatment to obtain the aluminum alloy.

6. The method of making an aluminum alloy of claim 5, wherein: The homogenization heat treatment comprises the following steps: first, heat preservation at 300-350℃ for 6-10h, then heating to 520-580℃ for 6-10h, and then cooling.

7. The method of making an aluminum alloy of claim 5, wherein: The extrusion forming has at least one of the following characteristics: (a1) the temperature of the extrusion forming is 520-570℃; (a2) the extrusion speed is 3-5min / min; (a3) the extrusion ratio is (10-25):

1.

8. The method of making an aluminum alloy of claim 5, wherein: The T6 heat treatment comprises the following steps: first, solution treatment, and then aging treatment; The solution treatment comprises the following steps: first, heat preservation at 300-350℃ for 4-6h, then heating to 560-580℃ for 6-8h, and then cooling to 200-300℃ by strong wind or water mist, and then cooling in air; The aging treatment comprises the following steps: heat preservation at 160-180℃ for 8-15h, and then cooling in air.

9. An air conditioning refrigeration apparatus characterized by comprising: The aluminum alloy or the component formed by the aluminum alloy according to any one of claims 1-4.

10. The aluminum alloy according to any one of claims 1-4 for use in the field of heat exchange.

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