High-strength high-conductivity aluminum alloy extrusion and method for producing the same

Abstract

The application discloses a high-strength and high-conductivity aluminum alloy extrusion piece and a preparation method thereof. The aluminum alloy comprises the following components in percentage by mass: Mg: 0.45-0.50%, Si: 0.30-0.38%, B: 0.05-0.15%, Hf: 0.05-0.015%, Ce: 0.05-0.15%, and the rest is Al. Through optimization of smelting, refining, hot top casting, hot extrusion and double-stage aging processes, the microstructure of the aluminum alloy is effectively controlled, a microstructure with fine grains and dispersed precipitated phase synergistic strengthening is obtained, and the mechanical properties and conductivity of the aluminum alloy are significantly improved. The conductivity of the aluminum alloy after the above treatment is above 60.0% IACS, and the aluminum alloy is high in strength. The application has important engineering value for expanding the application of the aluminum alloy in the fields of new energy equipment and high-voltage power transmission.

Description

Technical Field

[0001] This invention belongs to the field of high-performance aluminum alloy material design and preparation technology, specifically relating to a high-strength, high-conductivity aluminum alloy extrusion and its preparation method. Background Technology

[0002] Aluminum alloys have electrical conductivity second only to copper alloys, and are widely used in power transmission, new energy power generation, and other fields. In recent years, technological advancements in materials science have significantly improved the conductivity of aluminum alloys, making "aluminum as a substitute for copper" a hot topic in the industry. Compared with copper alloys, aluminum alloys have advantages such as lower cost, lower density, better casting performance, and a lower coefficient of thermal expansion. Moreover, for the same current carrying capacity, aluminum conductors weigh only half as much as copper conductors. Using aluminum alloy conductive profiles has a significant price advantage and a promising market prospect.

[0003] 6-series aluminum alloys are wrought aluminum alloys with aluminum, magnesium, and silicon as the main alloying elements. They are the most important extrusion alloys. Traditional 6-series aluminum alloys have excellent processing and forming properties and moderate mechanical strength, and are widely used in the manufacture of industrial structural components. However, their inherent electrical conductivity is usually below 60% IACS, making it difficult to meet the high conductivity requirements of the power transmission field. To address this, existing technologies often employ the introduction of high-cost alloying elements (such as rare earth elements) or complex post-processing techniques such as multi-stage aging to improve conductivity. However, the former leads to a significant increase in material costs, while the latter easily causes coarse matrix strengthening phases, resulting in damage to mechanical properties. Therefore, how to develop a new manufacturing process that can substantially improve the electrical conductivity of aluminum alloys while maintaining their original strength and processing characteristics, and at the same time avoid the economic decline caused by traditional strengthening methods, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a precision manufacturing process for high-strength, high-conductivity aluminum alloy extrusions. By optimizing the casting, extrusion, and two-stage aging process parameters, the conductivity is significantly improved (≥60% IACS) while maintaining excellent mechanical properties and processing efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] First, the present invention provides a high-strength, high-conductivity aluminum alloy extrusion, comprising the following components by mass percentage: Mg: 0.45-0.50%, Si: 0.30-0.38%, B: 0.05-0.15%, Hf: 0.05-0.015%, Ce: 0.05-0.15%, with the remainder being Al.

[0007] In this invention, Si and Mg form a Mg5Si6 strengthening phase, significantly improving the strength of the aluminum alloy through second-phase strengthening. Ce combines with harmful impurities in the aluminum melt to form stable high-melting-point intermetallic compounds (Al-Si-Ce), reducing the solid solution of impurities in the aluminum matrix, decreasing lattice distortion, and significantly reducing electron scattering, thereby improving conductivity. Hf combines with light elements such as oxygen and nitrogen to form HfO2 or HfN particles, reducing the obstruction of electron migration by non-metallic inclusions in the matrix and optimizing conductivity. Furthermore, the addition of Ce and Hf refines the grains and suppresses the segregation of impurity elements at grain boundaries, reducing electron scattering at grain boundaries and thus improving conductivity. A reasonable configuration of the aluminum alloy's composition can significantly improve its strength, resulting in a linear conductivity of ≥60.0% IACS for medium-strength aluminum alloys.

[0008] Furthermore, the conductivity of the aluminum alloy extrusion is ≥60.0% IACS.

[0009] Furthermore, this invention provides a method for preparing high-strength, high-conductivity aluminum alloy extrusions, comprising the following steps:

[0010] Step 1: Ingredients

[0011] Weigh the raw materials according to their mass percentage;

[0012] Step Two: Smelting and Refining

[0013] The aluminum, magnesium, and silicon weighed in step one are melted at 700-780℃ to form an aluminum alloy melt. Then, Al-3Hf master alloy is added. Electromagnetic stirring is used to ensure that the alloying elements are evenly distributed in the melt and to prevent local component segregation. The aluminum alloy melt is purified by blowing with 99.99% argon gas to remove gas and impurities and remove slag from the surface of the aluminum alloy melt. Finally, Al-10Ce master alloy is added and the melt is allowed to stand at 700-750℃ for 10-30 minutes. Then, the aluminum alloy melt is passed through an online degassing device and a two-stage filtration device.

[0014] Step 3: Hot Top Casting

[0015] The casting is carried out using a hot-top casting machine, and the solidification rate is controlled by bottom cooling water. During the casting process, AlB3 grain refiner is added online under electromagnetic stirring to refine the grains, prevent columnar crystal formation, and optimize the uniformity of the structure. Finally, the ingot is cooled and removed.

[0016] Step 4: Solution treatment

[0017] The ingot blank processed in step three is used to remove surface defects and solidification defects, and then subjected to solution treatment. The temperature range of the solution treatment step is 510 to 580°C, and the holding time is 4 to 10 hours.

[0018] Step 5: Hot extrusion treatment

[0019] Hot extrusion deformation is carried out using an extrusion press. The extruded profile is then rapidly cooled to room temperature using a water mist rapid cooling online quenching device. The precipitated phase hinders plastic deformation through the dislocation pinning effect. The coherent precipitated phase β”-Mg5Si6 (acicular) strengthens the structure through a shearing mechanism. Dislocation slip requires the destruction of its ordered structure and the overcoming of coherent strain to improve strength.

[0020] Step Six: Two-Level Time-Limited Processing

[0021] First, the hot-extruded profile is heated to 180-240℃ and held for 3-8 hours, then air-cooled to room temperature. Then, the profile that has undergone one aging treatment is heated to 220-240℃ and held for 8-12 hours, then air-cooled to room temperature.

[0022] Preferably, the melting temperature in step two is 700-750°C, and the settling temperature is 700-750°C.

[0023] Preferably, in step two, the Al-3Hf master alloy contains 2.5-3.5% Hf by mass, ≤0.1% impurities by mass, and the remainder is Al, with a size of 10mm-30mm; the Al-10Ce master alloy contains 9.5-10.3% Ce by mass, ≤0.1% impurities by mass, and the remainder is Al, with a size of 10mm-30mm.

[0024] Preferably, in step three, the casting temperature is 680~730℃, the casting water pressure is 0.15±0.05MPa, the casting water temperature is ≤40℃, and the casting speed is 170~210mm / min.

[0025] Preferably, in step three, the amount of AlB3 grain refiner added is 4-6 kg of AlB3 grain refiner per 1000 kg of alloy melt, that is, the mass fraction of AlB3 grain refiner added is 0.4 wt.% to 0.6 wt.%. The added AlB3 grain refiner mainly reacts with impurity elements such as V in the melt to form slag, which is removed during refining. Finally, the content of B in the melt is about 0.05-0.15%.

[0026] Preferably, in step four, surface defects and solidification defects of the billet are removed by mechanical processing to obtain a billet with a diameter of 90 mm and a length of 6000 mm.

[0027] Preferably, the solution temperature in step four is 560–580°C, and the holding time is 6–8 hours.

[0028] Preferably, in step five, the extrusion temperature is 450-550℃, the extrusion ratio is (30-60):1, and the extrusion speed is controlled at 4.0mm-8mm / s.

[0029] Preferably, the method further includes step seven: immersing the profile treated in step five into a solution containing 1-5 g / L CeCl3 and 5-10 mL / L H2O2, treating it at 50-70°C for 5-10 min, removing it and drying it at 60-80°C for 10-15 min, and then treating it with a 10-20V, 50-100Hz pulsed electric field for 2-4 min.

[0030] A solution containing Ce salt is used as the modifying liquid, along with an appropriate amount of strong oxidant and film formation assisted by an electric field, to form a dense conversion film composed of CeO2 and Ce(OH)3 on the surface of aluminum alloy. This film can effectively block the contact between corrosive media and the substrate. Furthermore, the film is thin and has little impact on the overall conductivity. In addition, Ce oxide itself has ionic conductivity, and the film has high porosity, allowing electrons to pass through, thus having a low impact on conductivity.

[0031] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a high-strength, high-conductivity aluminum alloy extrusion and its preparation method, which has the following beneficial effects:

[0032] The high-conductivity, medium-strength aluminum alloy wire produced by the process of this invention has the characteristics of high conductivity and high strength, and can be used in long-span, long-distance, high-voltage transmission lines, resulting in significant economic benefits.

[0033] This invention employs a hot-top casting machine with a horizontal pouring process, which allows the molten metal to complete the filling process in a stable flow state. This effectively prevents oxide inclusion defects caused by turbulent flow of liquid metal, avoids the turbulence phenomenon caused by liquid flow impact in traditional pouring methods, and further suppresses secondary oxide inclusions generated by contact between the molten metal and air.

[0034] The degassing method of this invention uses high-purity 99.99% argon gas blown in at high temperature. Argon gas has high inertness and good protection for the aluminum alloy liquid, making the aluminum alloy liquid less prone to oxidation, reducing metal oxides and gaseous impurities, preventing the tendency of alloy porosity, improving the mechanical properties of aluminum alloy and enhancing its electrical conductivity.

[0035] This invention employs online addition of AlB3. After dissolution, the refining agent is stirred at high speed by a rotor in an online degassing device, ensuring that the refining agent is evenly distributed in the aluminum alloy liquid. This reduces thermal stress caused by solidification shrinkage, minimizes hot cracking, refines the grain size of the casting, and prevents the formation of coarse equiaxed crystals, columnar crystals, and feathery crystals.

[0036] In this invention, during the hot extrusion process, a short-time solution treatment at 510–580°C is first performed to fully dissolve the phase particles in the alloy, maximizing the number of solute atoms in the Mg and Si matrix. The solute atoms dissolving into the aluminum matrix to form a supersaturated solid solution strengthen the alloy through solid solution treatment. The hot extrusion process uses an extruder for hot extrusion deformation. The extruded profile is then rapidly cooled to room temperature using a water mist rapid cooling online quenching device to obtain a metastable supersaturated solid solution, creating favorable conditions for the subsequent two-stage aging precipitation of the second phase.

[0037] This invention employs a two-stage aging treatment method for aluminum alloy profiles, controlling temperature and time to ensure uniform distribution of alloy precipitates, thereby enabling high-conductivity, medium-strength aluminum alloy profiles to maintain high strength while possessing good electrical conductivity. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 TEM images of nanoscale precipitates after two-stage aging of high conductivity aluminum alloy I at 220℃×5h+220℃×8h.

[0040] Figure 2 TEM images of nanoscale precipitates after two-stage aging of high-conductivity aluminum alloy II at 200℃×3h+220℃×12h.

[0041] Figure 3 Scanning electron microscope image of high conductivity aluminum alloy I after two-stage aging at 220℃×5h+220℃×8h;

[0042] Figure 4 Scanning electron microscope image of high conductivity aluminum alloy II after two-stage aging at 200℃×3h+220℃×12h;

[0043] Figure 5 The graph shows the change in conductivity of high conductivity aluminum alloy I after two-stage aging at 220℃×5h+220℃×8h, 10h, and 12h.

[0044] Figure 6 The graph shows the change in conductivity of high conductivity aluminum alloy II after two-stage aging at 200℃×3h+220℃×8h, 10h, and 12h. Detailed Implementation

[0045] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] The alloy composition of high-strength, high-conductivity aluminum alloy I is shown in Table 1:

[0048] Table 1. Composition of High-Strength, High-Conductivity Aluminum Alloy I (wt.%)

[0049] Mg Si Ce Hf B Al 0.45 0.35 0.12 0.014 0.10 margin

[0050] The preparation method is as follows:

[0051] Step 1: Ingredients

[0052] Weigh the raw materials according to their mass percentage;

[0053] Step Two: Smelting and Refining

[0054] The aluminum, magnesium, and silicon weighed in step one are melted at 715–720℃ to form an aluminum alloy melt. Then, an Al-3Hf master alloy is added and stirred evenly. The aluminum alloy melt is then refined by blowing with 99.99% argon gas to remove gas and impurities, and to remove slag from the surface of the aluminum alloy melt. Finally, an Al-10Ce master alloy is added and the melt is allowed to stand at 700–750℃ for 10–30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device. In the Al-3Hf master alloy, the mass percentage of Hf is 2.5–3.5%, the mass percentage of impurities is ≤0.1%, and the remainder is Al, with a size of 10 mm–30 mm. In the Al-10Ce master alloy, the mass percentage of Ce is 9.5–10.3%, the mass percentage of impurities is ≤0.1%, and the remainder is Al, with a size of 10 mm–30 mm.

[0055] Step 3: Hot Top Casting

[0056] Casting is carried out using a hot-top casting machine at a casting temperature of 680–730℃, a casting water pressure of 0.15±0.05MPa, a casting water temperature of ≤40℃, and a casting speed of 170–210 mm / min. During the casting process, AlB3 grain refiner is added online under stirring conditions at a rate of 5 kg of AlB3 grain refiner per 1000 kg of alloy melt to ensure that the aluminum alloy grain size reaches Grade I or above. Finally, the ingot is cooled and removed to obtain an aluminum alloy round bar with a diameter of 90 mm and a length of 6000 mm.

[0057] Step 4: Solution treatment

[0058] The surface defects and solidification defects of the billet are removed by mechanical processing, and then solution treatment is performed. The temperature range of the solution treatment step is 510 to 520°C, and the holding time is 4 to 10 hours.

[0059] Step 5: Hot extrusion treatment

[0060] Hot extrusion deformation is carried out using an extrusion press at an extrusion temperature of 520-530℃, an extrusion ratio of 58, and an extrusion speed of 2.3mm / s. The extruded profile is then rapidly cooled to room temperature using a water mist rapid cooling online quenching device.

[0061] Step Six: Two-Level Time-Limited Processing

[0062] First, the hot-extruded profile is heated to 220℃ and held for 5 hours, then air-cooled to room temperature. Then, the profile that has undergone one aging treatment is heated to 220℃ and held for 8 hours, then air-cooled to room temperature.

[0063] Step 7: Surface Treatment

[0064] The profiles treated in step five are immersed in a solution containing 3 g / L CeCl3 and 8 mL / L H2O2 and treated at 60°C for 8–10 min. After being taken out, they are dried at 70°C for 12–14 min, and then treated with a 15 V, 80 Hz pulsed electric field for 3 min.

[0065] Example 2

[0066] The alloy composition of high-strength, high-conductivity aluminum alloy II is shown in Table 1:

[0067] Table 1. Composition of High-Strength, High-Conductivity Aluminum Alloy I (wt.%)

[0068] Mg Si Ce Hf B Al 0.45 0.35 0.12 0.014 0.10 margin

[0069] The preparation method is as follows:

[0070] Step 1: Ingredients

[0071] Weigh the raw materials according to their mass percentage;

[0072] Step Two: Smelting and Refining

[0073] The aluminum, magnesium, and silicon weighed in step one are melted at 715–720℃ to form an aluminum alloy melt. Then, an Al-3Hf master alloy is added and stirred evenly. The aluminum alloy melt is then refined by blowing with 99.99% argon gas to remove gas and impurities, and to remove slag from the surface of the aluminum alloy melt. Finally, an Al-10Ce master alloy is added and the melt is allowed to stand at 700–750℃ for 10–30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device. In the Al-3Hf master alloy, the mass percentage of Hf is 2.5–3.5%, the mass percentage of impurities is ≤0.1%, and the remainder is Al, with a size of 10 mm–30 mm. In the Al-10Ce master alloy, the mass percentage of Ce is 9.5–10.3%, the mass percentage of impurities is ≤0.1%, and the remainder is Al, with a size of 10 mm–30 mm.

[0074] Step 3: Hot Top Casting

[0075] Casting is carried out using a hot-top casting machine at a casting temperature of 680–730℃, a casting water pressure of 0.15±0.05MPa, a casting water temperature of ≤40℃, and a casting speed of 170–210 mm / min. During the casting process, AlB3 grain refiner is added online under stirring conditions at a rate of 6 kg of AlB3 grain refiner per 1000 kg of alloy melt to ensure that the aluminum alloy grain size reaches level one or above. Finally, the ingot is cooled and removed to obtain an aluminum alloy round bar with a diameter of 90 mm and a length of 6000 mm.

[0076] Step 4: Solution treatment

[0077] The surface defects and solidification defects of the billet are removed by mechanical processing, and then solution treatment is performed. The temperature range of the solution treatment step is 510 to 520°C, and the holding time is 4 to 10 hours.

[0078] Step 5: Hot extrusion treatment

[0079] Hot extrusion deformation is carried out using an extrusion press at an extrusion temperature of 520-530℃, an extrusion ratio of 58, and an extrusion speed of 2.5mm / s. The extruded profile is then rapidly cooled to room temperature using a water mist rapid cooling online quenching device.

[0080] Step Six: Two-Level Time-Limited Processing

[0081] First, the hot-extruded profile is heated to 200℃ and held for 3 hours, then air-cooled to room temperature. Then, the profile that has undergone one aging treatment is heated to 220℃ and held for 12 hours, then air-cooled to room temperature.

[0082] Step 7: Surface Treatment

[0083] The profiles treated in step five were immersed in a solution containing 5 g / L CeCl3 and 10 mL / L H2O2, treated at 70°C for 5 min, removed and dried at 80°C for 10 min, and then treated with a 20 V, 100 Hz pulsed electric field for 2 min.

[0084] The alloy-related property diagrams for Examples 1-2 are attached. Figure 1-6 As shown, by Figure 1-2 It is known that the precipitated phases pinning dislocations in high-conductivity aluminum alloys I and II can effectively improve the material strength. (From the attached...) Figure 3-4 It is known that Ce in high conductivity aluminum alloy I forms stable high-melting-point intermetallic compounds with harmful impurities in the aluminum melt, reducing the solid solution of impurities in the aluminum matrix, reducing lattice distortion, significantly reducing electron scattering, and improving conductivity; Ce in high conductivity aluminum alloy II can refine grains and suppress the segregation of impurity elements at grain boundaries, reducing the scattering of electrons by grain boundaries, thereby improving conductivity.

[0085] The high conductivity aluminum alloys prepared in Examples 1 and 2 have conductivity of 60.30% IACS and 60.45% IACS, respectively.

[0086] Comparative Example 1

[0087] The difference from Example 1 is that in the multi-stage aging treatment, the first stage aging was 220℃×5h, followed by air cooling to room temperature, and the second stage aging was 240℃×8h, followed by air cooling to room temperature. The resulting aluminum alloy profile had a conductivity of 60.10% IACS. This result is due to the excessively high temperature of the two-stage aging process, which led to coarsening of the aluminum matrix grains and abnormal growth of the precipitated strengthening phases, affecting both conductivity and strength.

[0088] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0089] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-strength, high-conductivity aluminum alloy extrusion, characterized in that, By mass percentage, it comprises the following components: Mg: 0.45–0.50%, Si: 0.30–0.38%, B: 0.05–0.15%, Hf: 0.05–0.015%, Ce: 0.05–0.15%, with the remainder being Al; The method for preparing the high-strength, high-conductivity aluminum alloy extrusion includes the following steps: Step 1: Ingredients Weigh the raw materials according to their mass percentage; Step Two: Smelting and Refining The aluminum, magnesium, and silicon weighed in step one are melted at 700-780℃ to form an aluminum alloy melt. Then, Al-3Hf master alloy is added and stirred evenly. The aluminum alloy melt is then purified by blowing with 99.99% argon gas to remove gas and impurities and remove slag from the surface of the aluminum alloy melt. Finally, Al-10Ce master alloy is added and the melt is allowed to stand at 700-750℃ for 10-30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device. Step 3: Hot Top Casting The casting is carried out by a hot-top casting machine, and the solidification rate is controlled by bottom cooling water. During the casting process, AlB3 grain refiner is added online under stirring conditions. Finally, the ingot is cooled and removed. Step 4: Solution treatment The ingot blank processed in step three is used to remove surface defects and solidification defects, and then subjected to solution treatment. The temperature range of the solution treatment step is 510 to 580°C, and the holding time is 4 to 10 hours. Step 5: Hot extrusion treatment The profile is hot extruded and deformed using an extrusion press, and then rapidly cooled to room temperature using a water mist rapid cooling online quenching device. Step Six: Two-Level Time-Limited Processing First, heat the hot-extruded profile to 180-240℃ and hold for 3-8 hours, then air-cool to room temperature. Then, heat the profile that has undergone one aging treatment to 220-240℃ and hold for 8-12 hours, then air-cool to room temperature. Step 7: Immerse the profile treated in Step 5 into a solution containing 1-5 g / L CeCl3 and 5-10 mL / L H2O2, treat at 50-70℃ for 5-10 min, remove and dry at 60-80℃ for 10-15 min, then treat with a pulsed electric field of 10-20 V and 50-100 Hz for 2-4 min.

2. The high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, The conductivity of the aluminum alloy extrusion is ≥60.0% IACS.

3. The high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, The melting temperature in step two is 700-750℃, and the settling temperature is 700-750℃.

4. The high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, In step two, the Al-3Hf master alloy contains 2.5-3.5% Hf by mass, ≤0.1% impurities by mass, and the remainder is Al, with a size of 10mm-30mm; the Al-10Ce master alloy contains 9.5-10.3% Ce by mass, ≤0.1% impurities by mass, and the remainder is Al, with a size of 10mm-30mm.

5. A high-strength, high-conductivity aluminum alloy extrusion as described in claim 1, characterized in that, In step three, the casting temperature is 680~730℃, the casting water pressure is 0.15±0.05MPa, the casting water temperature is ≤40℃, and the casting speed is 170~210mm / min.

6. A high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, In step three, the amount of AlB3 grain refiner added is 4-6 kg per 1000 kg of alloy melt, which is 0.4 wt.% to 0.6 wt.% by mass. The added AlB3 grain refiner mainly reacts with impurity element V in the melt to form slag, which is removed during refining. Finally, the content of B in the melt is 0.05-0.15%.

7. A high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, The solution temperature in step four is 560–580°C, and the holding time is 6–8 hours.

8. A high-strength, high-conductivity aluminum alloy extrusion according to claim 1, characterized in that, In step five, the extrusion temperature is 450-550℃, the extrusion ratio is (30-60):1, and the extrusion speed is controlled at 4.0mm-8mm / s.

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