High-strength and high-conductivity aluminum alloy extrusion part and preparation method thereof

Abstract

The invention discloses a high-strength and high-conductivity aluminum alloy extrusion part and a preparation method thereof. The aluminum alloy comprises the following components in percentage by mass: 0.45 to 0.50 percent of Mg, 0.30 to 0.38 percent of Si, 0.05 to 0.15 percent of B, 0.05 to 0.015 percent of Hf, 0.05 to 0.15 percent of Ce and the balance of Al. By optimizing smelting, refining, hot top casting, hot extrusion and two-stage aging processes, the microstructure of the aluminum alloy is effectively regulated and controlled, the microstructure synergistically strengthened by fine grains and dispersed precipitation phases is obtained, and the mechanical property and the electric conductivity of the aluminum alloy are remarkably improved. The electric conductivity of the treated aluminum alloy reaches 60.0% IACS or above, and meanwhile the aluminum alloy has high strength. The method has important engineering value for expanding the application of the aluminum alloy in the fields of new energy equipment, high-voltage power transmission and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of design and preparation of high-performance aluminum alloy materials, and particularly relates to a high-strength and high-conductivity aluminum alloy extrusion part and a preparation method thereof. Background Art

[0002] Aluminum alloys, second only to copper alloys in electrical conductivity, are widely used in power transmission, renewable energy generation, and other fields. In recent years, technological advances in materials science have significantly improved the conductivity of aluminum alloys, making the use of aluminum instead of copper a hot topic in the industry. Compared with copper alloys, aluminum alloys offer advantages such as lower cost, lower density, better casting properties, and a lower coefficient of thermal expansion. Furthermore, at the same current carrying capacity, aluminum conductors weigh only half as much as copper. Therefore, the use of aluminum alloy conductive profiles offers significant price advantages and promising market prospects.

[0003] 6 series aluminum alloy is a deformable aluminum alloy with aluminum, magnesium and silicon as the main alloying elements. It is the most important extrusion alloy. Traditional 6 series aluminum alloy has excellent processing and forming properties and moderate mechanical strength. It is widely used in the preparation of industrial structural parts, but its inherent electrical conductivity is usually lower than 60% IACS, which makes it difficult to meet the high conductivity requirements in the field of power transmission. In response to this, existing technologies often use the introduction of high-cost alloying elements (such as rare earth elements) or the implementation of complex post-treatment processes such as multi-stage aging to improve conductivity, but the former leads to a significant increase in material costs, and the latter easily causes the matrix strengthening phase to coarsen and thus impair the mechanical properties. In view of this, how to develop a new preparation process that enables aluminum alloys to achieve substantial improvements in electrical conductivity while maintaining the original strength indicators and processing characteristics, while avoiding the economic decline caused by traditional strengthening methods is a problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a refined preparation process for high-strength and 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 object, the present invention adopts the following technical solutions:

[0006] First, the present invention provides a high-strength and high-conductivity aluminum alloy extrusion, which includes the following components, in 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%, and the rest is Al.

[0007] The Si and Mg in the present invention's formula form a strengthening phase called Mg5Si6, significantly improving the strength of the aluminum alloy through secondary phase strengthening. The Ce element forms a stable, high-melting-point intermetallic compound (Al-Si-Ce) with harmful impurities in the aluminum melt, reducing the solid solution of impurities in the aluminum matrix, reducing lattice distortion, and significantly reducing electron scattering, thereby improving conductivity. The Hf element 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 while inhibiting the segregation of impurity elements at grain boundaries, reducing electron scattering at grain boundaries, and thus improving conductivity. Rational configuration of the aluminum alloy's component content can significantly improve its strength, enabling the conductivity of medium-strength aluminum alloy wire to reach ≥60.0% IACS.

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

[0009] In addition, the present invention provides a method for preparing a high-strength and high-conductivity aluminum alloy extrusion, comprising the following steps:

[0010] Step 1: Ingredients

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

[0012] Step 2: Smelting and Refining

[0013] The aluminum, magnesium, and silicon weighed in step 1 are melted at 700-780° C. to form an aluminum alloy melt, and then an Al-3Hf master alloy is added. Electromagnetic stirring is performed to ensure that the alloy elements are evenly distributed in the melt to prevent local component segregation. The aluminum alloy melt is subjected to spray refining, degassing, and impurity removal with 99.99% argon gas to remove scum on the surface of the aluminum alloy melt. Finally, an Al-10Ce master alloy is added, and the mixture is allowed to stand at 700-750° C. for 10-30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device.

[0014] Step 3: Hot Top Casting

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

[0016] Step 4: Solution treatment

[0017] The ingot body treated in step 3 is subjected to surface defects and solidification defects, and is subjected to solution treatment, wherein the temperature range of the solution treatment step is 510-580° C. and the holding time is 4-10 hours;

[0018] Step 5: Hot extrusion treatment

[0019] Hot extrusion deformation is carried out using an extruder. 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, while the coherent precipitated phase β"-Mg5Si6 (acicular) dominates strengthening through a shearing mechanism. Dislocation slip requires the destruction of its ordered structure and the overcoming of the coherent strain, thereby increasing strength.

[0020] Step 6: Double-stage aging treatment

[0021] First, heat the hot extruded deformed profile to 180-240°C and keep it warm for 3-8 hours, then air-cool it to room temperature. Then, heat the profile that has undergone one aging treatment to 220-240°C and keep it warm for 8-12 hours, then air-cool it to room temperature.

[0022] Preferably, the smelting temperature in step 2 is 700-750°C, and the standing temperature is 700-750°C.

[0023] Preferably, in step 2, the Al-3Hf master alloy has a Hf mass percentage of 2.5-3.5%, an impurity mass percentage of ≤0.1%, and the rest is Al, with a size of 10 mm to 30 mm; the Al-10Ce master alloy has a Ce mass percentage of 9.5-10.3%, an impurity mass percentage of ≤0.1%, and the rest is Al, with a size of 10 mm to 30 mm.

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

[0025] Preferably, the amount of AlB3 grain refiner added in step three is: 4 to 6 kg of AlB3 grain refiner is added to every 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 refiner mainly undergoes metallurgical reactions 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 to 0.15%.

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

[0027] Preferably, the solution temperature in step 4 is 560-580° C., and the holding time is 6-8 hours.

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

[0029] Preferably, the method further includes step seven: immersing the profile treated in step five in a solution containing 1-5 g / LCeCl3 and 5-10 mL / L H2O2, treating 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 10-20 V, 50-100 Hz pulse electric field for 2-4 min.

[0030] A solution containing Ce salt is used as the modifying liquid, combined with an appropriate amount of strong oxidant and electric field-assisted film formation to form a dense conversion film composed of CeO2 and Ce(OH)3 on the surface of the aluminum alloy, which can effectively block the contact between the corrosive medium and the substrate. The film layer is thin and has little effect on the overall conductivity. The Ce oxide itself has ionic conductivity, the film layer has a high porosity, allows electrons to pass through, and has little effect on conductivity.

[0031] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a high-strength and high-conductivity aluminum alloy extrusion and a preparation method thereof, which has the following beneficial effects:

[0032] The high-conductivity medium-strength aluminum alloy wire prepared by the process of the present invention has the characteristics of high conductivity and high strength, can be used for large-span, large-drop, long-distance high-voltage transmission lines, and has significant economic benefits.

[0033] The present invention adopts a horizontal pouring process of a hot top casting machine, so that the molten metal completes the filling process in a stable flow state, thereby effectively preventing oxidation inclusion defects caused by turbulent liquid metal flow, avoiding the turbulence phenomenon caused by liquid flow impact in traditional pouring methods, and further suppressing secondary oxidation inclusions generated by the contact between the molten metal and the air.

[0034] The degassing method of the present invention adopts high-purity 99.99% argon gas to be blown in at high temperature. The argon gas is highly inert and has good protection for the aluminum alloy liquid, making the aluminum alloy liquid less likely to be oxidized, reducing metal oxides and gas impurities, preventing the occurrence of alloy pores, improving the mechanical properties of the aluminum alloy and improving the electrical conductivity of the aluminum alloy.

[0035] The present invention adopts online addition of AlB3. After dissolution, the refiner is stirred at high speed by the rotor in the online degassing device, so that the refiner is evenly distributed in the aluminum alloy liquid, reducing the thermal stress caused by solidification shrinkage, reducing thermal cracking, refining the casting grains, and preventing the generation of coarse equiaxed crystals, columnar crystals and feather crystals.

[0036] During the hot extrusion process, the present invention first performs a short solution treatment at 510-580°C to fully dissolve the phase particles in the alloy, maximizing the number of solute atoms in the Mg and Si matrix. These solute atoms, dissolved into the aluminum matrix to form a supersaturated solid solution, strengthen the alloy. The hot extrusion process uses an extruder for hot extrusion deformation. The extruded profile then passes through an online water mist rapid cooling quenching device to ensure rapid cooling to room temperature after extrusion, resulting in a metastable supersaturated solid solution and creating favorable conditions for the precipitation of the second phase during the subsequent two-stage aging process.

[0037] The present invention adopts a double-stage aging treatment method for the aluminum alloy profile, and controls the temperature and time to uniformly distribute the alloy precipitation phase, so that the high-conductivity and medium-strength aluminum alloy profile has good electrical conductivity while maintaining high strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 This is the TEM image of nanoscale precipitation phase after double-stage aging of high conductivity aluminum alloy I at 220℃×5h+220℃×8h;

[0040] Figure 2 This is the TEM image of nanoscale precipitation phase after double-stage aging of high conductivity aluminum alloy II at 200℃×3h+220℃×12h;

[0041] Figure 3 This is the scanning electron microscope image of high conductivity aluminum alloy I after double-stage aging at 220℃×5h+220℃×8h;

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

[0043] Figure 5 This is the conductivity change diagram of high conductivity aluminum alloy I after double-stage aging at 220℃×5h+220℃×8h, 10h, and 12h;

[0044] Figure 6 This is a diagram showing the conductivity change of high conductivity aluminum alloy II after double-stage aging at 200℃×3h+220℃×8h, 10h, and 12h. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] Example 1

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

[0048] Table 1 Composition of high strength and 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 mass percentage;

[0053] Step 2: Smelting and Refining

[0054] The aluminum, magnesium, and silicon weighed in step 1 are melted at 715-720° C. to form an aluminum alloy melt, and then an Al-3Hf master alloy is added and stirred for uniform distribution. The aluminum alloy melt is subjected to spray refining, degassing, and impurity removal with 99.99% argon gas to remove scum on the surface of the aluminum alloy melt. Finally, an Al-10Ce master alloy is added, and the mixture is allowed to stand at 700-750° C. for 10-30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device. The Al-3Hf master alloy has a Hf mass percentage of 2.5-3.5%, an impurity mass percentage of ≤0.1%, and the remainder is Al, and the size is 10 mm to 30 mm; the Al-10Ce master alloy has a Ce mass percentage of 9.5-10.3%, an impurity mass percentage of ≤0.1%, and the remainder is Al, and the size is 10 mm to 30 mm.

[0055] Step 3: Hot Top Casting

[0056] The aluminum alloy is cast using a hot top casting machine at a casting temperature of 680-730°C, a casting water pressure of 0.15±0.05 MPa, a casting water temperature of ≤40°C, and a casting speed of 170-210 mm / min. During the casting process, an AlB3 grain refiner is added online under stirring conditions in an amount of 5 kg AlB3 grain refiner per 1000 kg of alloy melt to ensure that the aluminum alloy grain size reaches level 1 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 ingot is mechanically processed to remove surface defects and solidification defects, and then subjected to solution treatment, wherein the temperature range of the solution treatment step is 510-520° C. and the holding time is 4-10 hours;

[0059] Step 5: Hot extrusion treatment

[0060] An extruder is used for hot extrusion deformation, with an extrusion temperature of 520-530°C, an extrusion ratio of 58, and an extrusion speed of 2.3 mm / s. The extruded profile is rapidly cooled to room temperature by a water mist rapid cooling online quenching device;

[0061] Step 6: Double-stage aging treatment

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

[0063] Step 7: Surface treatment

[0064] The profile treated in step five was immersed in a solution containing 3 g / L CeCl3 and 8 mL / L H2O2 at 60°C for 8 to 10 minutes. After being removed, it was dried at 70°C for 12 to 14 minutes, and then treated with a 15V, 80Hz pulse electric field for 3 minutes.

[0065] Example 2

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

[0067] Table 1 Composition of high strength and 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 mass percentage;

[0072] Step 2: Smelting and Refining

[0073] The aluminum, magnesium, and silicon weighed in step 1 are melted at 715-720° C. to form an aluminum alloy melt, and then an Al-3Hf master alloy is added and stirred for uniform distribution. The aluminum alloy melt is subjected to spray refining, degassing, and impurity removal with 99.99% argon gas to remove scum on the surface of the aluminum alloy melt. Finally, an Al-10Ce master alloy is added, and the mixture is allowed to stand at 700-750° C. for 10-30 minutes. The aluminum alloy melt is then passed through an online degassing device and a two-stage filtration device. The Al-3Hf master alloy has a Hf mass percentage of 2.5-3.5%, an impurity mass percentage of ≤0.1%, and the remainder is Al, and the size is 10 mm to 30 mm; the Al-10Ce master alloy has a Ce mass percentage of 9.5-10.3%, an impurity mass percentage of ≤0.1%, and the remainder is Al, and the size is 10 mm to 30 mm.

[0074] Step 3: Hot Top Casting

[0075] The aluminum alloy is cast using a hot top casting machine at a casting temperature of 680-730°C, a casting water pressure of 0.15±0.05 MPa, a casting water temperature of ≤40°C, and a casting speed of 170-210 mm / min. During the casting process, an AlB3 grain refiner is added online under stirring conditions in an amount of 6 kg AlB3 grain refiner per 1000 kg of alloy melt to ensure that the aluminum alloy grain size reaches level 1 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 ingot is mechanically processed to remove surface defects and solidification defects, and then subjected to solution treatment, wherein the temperature range of the solution treatment step is 510-520° C. and the holding time is 4-10 hours;

[0078] Step 5: Hot extrusion treatment

[0079] An extruder is used for hot extrusion deformation, with an extrusion temperature of 520-530°C, an extrusion ratio of 58, and an extrusion speed of 2.5 mm / s. The extruded profile is rapidly cooled to room temperature by a water mist rapid cooling online quenching device;

[0080] Step 6: Double-stage aging treatment

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

[0082] Step 7: Surface treatment

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

[0084] The alloy performance diagrams of Examples 1-2 are shown in the attached diagram. Figure 1-6 As shown by Figure 1-2 It can be seen that the precipitation phases of high conductivity aluminum alloys I and II pin dislocations and effectively improve the strength of the material. Figure 3-4 It can be seen that the Ce element in high-conductivity aluminum alloy I forms a stable high-melting-point intermetallic compound with harmful impurities in the aluminum melt, reducing the solid solution of impurities in the aluminum matrix, reducing the lattice distortion, significantly reducing electron scattering, and improving conductivity; the Ce element in high-conductivity aluminum alloy II can refine the grains, while inhibiting the segregation of impurity elements at the grain boundaries, reducing the scattering of electrons by the grain boundaries, and thus improving conductivity.

[0085] The electrical conductivities of the high-conductivity aluminum alloys prepared in Example 1 and Example 2 are 60.30% IACS and 60.45% IACS, respectively.

[0086] Comparative Example 1

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

[0088] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0089] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-strength and high-conductivity aluminum alloy extrusion, characterized in that: Calculated by mass percentage, it includes 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%, and the rest is Al.

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

3. A method for preparing a high-strength and high-conductivity aluminum alloy extrusion, characterized in that: The following steps are involved: Step 1: Ingredients Weigh the raw materials according to mass percentage; Step 2: Smelting and Refining The aluminum, magnesium, and silicon weighed in step 1 are melted at 700-780° C. to form an aluminum alloy melt, and then an Al-3Hf master alloy is added and stirred for uniform distribution. The aluminum alloy melt is subjected to degassing and impurity removal by spraying with 99.99% argon gas to remove scum on the surface of the aluminum alloy melt, and finally an Al-10Ce master alloy is added. The mixture is allowed to stand at 700-750° C. for 10-30 minutes, and then the aluminum alloy melt is passed through an online degassing device and a two-stage filtration device; Step 3: Hot Top Casting The ingot is cast in a hot top casting machine and the solidification rate is controlled by cooling water at the bottom. 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 body treated in step 3 is subjected to surface defects and solidification defects, and is subjected to solution treatment, wherein the temperature range of the solution treatment step is 510-580° C. and the holding time is 4-10 hours; Step 5: Hot extrusion treatment The extruder is used for hot extrusion deformation, and the deformed profile is rapidly cooled to room temperature by a water mist rapid cooling online quenching device; Step 6: Double-stage aging treatment First, heat the hot extruded deformed profile to 180-240°C and keep it warm for 3-8 hours, then air-cool it to room temperature. Then, heat the profile that has undergone one aging treatment to 220-240°C and keep it warm for 8-12 hours, then air-cool it to room temperature.

4. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: The smelting temperature in step 2 is 700-750°C, and the standing temperature is 700-750°C.

5. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: In step 2, the Al-3Hf master alloy has a Hf mass percentage of 2.5-3.5%, an impurity mass percentage of ≤0.1%, and the rest is Al, with a size of 10mm-30mm; the Al-10Ce master alloy has a Ce mass percentage of 9.5-10.3%, an impurity mass percentage of ≤0.1%, and the rest is Al, with a size of 10mm-30mm.

6. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: In step 3, the casting temperature is: 680-730° C., the casting water pressure is 0.15±0.05 MPa, the casting water temperature is ≤40° C., and the casting speed is 170-210 mm / min.

7. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: In step 3, the amount of AlB3 grain refiner added is: 4 to 6 kg of AlB3 grain refiner is added to every 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 undergoes metallurgical reactions 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 to 0.15%.

8. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: The solution temperature in step 4 is 560-580° C., and the holding time is 6-8 hours.

9. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: In step 5, the extrusion temperature is 450-550° C., the extrusion ratio is (30-60):1, and the extrusion speed is controlled at 4.0 mm-8 mm / s.

10. The method for preparing a high-strength and high-conductivity aluminum alloy extrusion according to claim 3, characterized in that: Also includes: Step 7: Immerse the profile treated in step 5 in a solution containing 1-5 g / L CeCl3 and 5-10 mL / L H2O2 at 50-70°C for 5-10 minutes, remove it and dry it at 60-80°C for 10-15 minutes, and then treat it with a 10-20 V, 50-100 Hz pulse electric field for 2-4 minutes.

Images