Preparation method of high-performance 6082 alloy

Abstract

The invention discloses a preparation method of a high-performance 6082 alloy, and relates to the technical field of alloy materials. Water-soluble aluminum salt and rare earth salt are utilized, and sodium carbonate precipitation and stirring are combined to prepare uniformly dispersed rare earth carbonate in aluminum hydroxide. Compared with traditional mechanical alloying, the fine-particle-size rare earth oxide enhanced aluminum powder obtained after calcination reduction has smaller and uniform particles, and abrasion pollution and oxidation are avoided. The aluminum-rare earth alloy powder is added into 6082 alloy melt, so that the mechanical property of the alloy can be improved, grains are refined, and oxide aggregation is reduced. And through stirring and rapid cooling, uniform dispersion and precipitation of the nano oxide are realized, and the performance and safety of the material are improved. In addition, nano silicon carbide and graphene are introduced to the surface, the self-lubricating and wear-resistant characteristics are achieved, a gradient structure layer is formed through nitrogen and ammonia mixed atmosphere treatment, and the friction resistance and the mechanical property are further optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a method for preparing a high-performance 6082 alloy. Background Art

[0002] As a representative of medium-high-strength weldable Al-Mg-Si alloys, 6082 aluminum alloy is widely used in transportation, aerospace, and mechanical structures due to its excellent formability, corrosion resistance, and moderate strength. However, with the increasing demand for lightweight, high-reliability components in modern industry, the mechanical properties of traditional 6082 alloy, especially its strength and wear resistance, have become increasingly difficult to meet the requirements of high-end working conditions.

[0003] Currently, the main approaches to improving the performance of 6082 alloy focus on two types of technologies: (1) Microalloying enhancement, which is often achieved by adding rare earth elements (such as Ce and Y) to form a strengthening phase. However, traditional processes mostly use direct melt doping of rare earths or mechanical alloying. The direct melt doping method is prone to rare earth oxidation and burning, component segregation, and aggregation of coarse rare earth-rich phases, which weakens the strengthening effect; although mechanical alloying can refine particles, it has problems such as grinding medium wear pollution, severe aluminum powder oxidation, high energy consumption, and poor particle size uniformity, which affect the homogeneity and performance stability of the final structure. (2) Surface strengthening treatment, such as thermal spraying and micro-arc oxidation, can introduce wear-resistant phases into the surface layer, but such technologies are difficult to achieve synergistic strengthening of the substrate and the surface layer, and the hard coating often aggravates friction and wear due to insufficient lubricity.

[0004] Therefore, there is an urgent need to develop an integrated technology that takes into account both matrix nano-strengthening and surface multifunctional modification, so as to systematically improve the comprehensive mechanical and tribological properties of 6082 alloy while retaining its inherent advantages. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing high-performance 6082 alloy to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing high-performance 6082 alloy, comprising the following preparation steps: (1) Aluminum salt and rare earth salt are mixed in a mass ratio of 10-50:1 to obtain a mixture, water is added, and after stirring for 15 minutes, sodium carbonate solution is added at 60-80 ° C. The total cations in the mixture are: CO3 2- The molar ratio is 1:1.8-2.2, and the mixture is stirred for 2-4 hours. After the stirring is completed, the mixture is allowed to stand, cooled, filtered, washed, and then transferred to a porcelain boat and placed in a muffle furnace for calcination to obtain aluminum-rare earth alloy powder; (2) Prepare aluminum alloy raw materials according to the following weight ratio: Si 0.95-1.1%, Mg 0.9~1.2%, Cu 0.05-0.15%, Mn 0.4~0.9%, Cr 0.13~0.18%, Ti 0.11~0.18%, Zn ≤ 0.05%, other individual impurities ≤ 0.03%, total impurities ≤ 0.10%, and the balance is Al. Add the prepared aluminum alloy raw materials into a melting furnace, mix them evenly, and then melt them into liquid aluminum alloy at a melting temperature of 700~750℃. Then add aluminum-rare earth alloy powder, stir and mix for 5min~60min, and then quickly cool to obtain aluminum alloy material; (3) Mixing the metal raw materials according to the mass ratio and smelting them under argon protection; adding potassium fluorotitanate and potassium fluoroborate into the melt, and performing electromagnetic stirring during the process to obtain an alloy melt; (4) The aluminum alloy material is heat treated at 500-570℃ for 2-3h, and the alloy melt, silicon carbide particles accounting for 3wt% of the alloy melt, and graphene accounting for 8wt% of the alloy melt are uniformly mixed. Under the conditions of argon working intensity of 3MPa and spray gun speed of 10mm / s, the mixture is sprayed on the surface of the aluminum alloy material to a thickness of 5-10μm. (5) A gas quenching furnace is used for rapid cooling to room temperature. The gas used in the gas quenching furnace is a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The cooling rate is 20℃ / min. Then, heat treatment is carried out at 500-570℃ for 2-3h in a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The above steps are repeated 1-2 times, and then aging strengthening is carried out: first, it is kept at 120℃ for 8h, then treated at 200℃ for 12h, and then cooled to 170℃ with the furnace and kept at this temperature for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material. After cooling to 100℃ with the furnace, it is switched to forced air cooling and continued to cool to room temperature. The wind speed is adjusted to achieve controllable convection heat exchange. The workpiece is removed when the temperature drops below 50℃ to obtain high-performance 6082 alloy.

[0007] Furthermore, the ratio of the mixture to water in step (1) is 1 g: (2-10) mL.

[0008] Furthermore, the concentration of the sodium carbonate solution in step (1) is 1-10 g / 100 mL.

[0009] Furthermore, in step (2), the mass ratio of the aluminum-rare earth alloy powder to the liquid aluminum alloy is 1:5-50.

[0010] Furthermore, the mass ratio of the metal raw materials in step (3) is: with aluminum as the matrix, the mass ratio is 4-6% magnesium, 3-5% lithium, 0.5-1% titanium and 0.2-0.5% scandium, and the rest is pure aluminum, forming a five-element alloy system.

[0011] Furthermore, the smelting parameters in step (3) are: vacuum degree is 0.5×10 -3 Pa, control the melt temperature at 800-850℃ and keep it warm for 20-30min, and introduce high-purity argon protection throughout the process with an argon flow rate of 15-20L / min to suppress the volatilization of lithium elements.

[0012] Furthermore, in step (3), the total amount of the mixed salt of potassium fluorotitanate and potassium fluoroborate added is 0.8-1.2% of the mass of the melt.

[0013] Furthermore, in step (3), the molar ratio of potassium fluorotitanate to potassium fluoroborate is 1:2.

[0014] Furthermore, in step (4), the particle size of the silicon carbide particles is 3 μm and the particle size of the graphene is 5 μm.

[0015] Furthermore, the wind speed in step (5) is 2-3 m / s.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses water-soluble aluminum salt and rare earth salt as precursors, precipitates them through sodium carbonate, and stirs them during the preparation process to achieve uniform dispersion of water-insoluble rare earth carbonate in the aluminum hydroxide precipitate, which is beneficial for the uniform dispersion of rare earth oxides in aluminum powder particles in the later process. By calcination and reduction, aluminum-rare earth alloy powder with fine particle size of rare earth oxide reinforced aluminum powder is obtained. Compared with traditional mechanical alloying, a small and uniform precursor can be formed in the early stage of precipitation. The particles after calcination and reduction inherit the high uniformity and small size of the precursor, and avoid wear pollution and aluminum powder oxidation caused by ball milling.

[0017] (2) The present invention adds aluminum-rare earth alloy powder to the 6082 alloy melt. The fine alloy powder can serve as an effective nucleation core to improve the mechanical properties of the 6082 alloy. The fine, dispersed rare earth-enriched phase formed can hinder the growth of grains and achieve grain refinement. Since the aluminum-rare earth alloy powder and the 6082 alloy melt are similar in composition, they are uniformly mixed, reducing the phenomenon of oxides floating, gathering and growing in the alloy melt. After stirring and rapid cooling, the nano-oxides are uniformly dispersed and precipitated, avoiding the problem of rapid growth of nano-oxides. On the basis of retaining the excellent performance of the 6082 alloy, the uniform dispersion distribution of the nano-oxide precipitation phase is achieved, further improving the mechanical properties and safety of the material.

[0018] (3) The present invention simultaneously introduces high-content nano-silicon carbide and pre-dispersed graphene on the surface of the formed aluminum alloy, and uses the interlayer slip characteristics of graphene to give the surface a self-lubricating function, while the high-hardness silicon carbide particles construct a wear-resistant skeleton. Under the synergistic effect of the two, the surface hardness and friction performance are simultaneously optimized. Then, a mixed atmosphere of nitrogen and ammonia is used for gas quenching and solid solution treatment, so that nitrogen atoms penetrate into the surface and form a gradient structure layer on its surface, further optimizing the friction resistance and mechanical properties of the 6082 alloy. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the 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.

[0020] In order to more clearly illustrate the method provided by the present invention, the following examples are provided in detail. The test methods for various indicators of a high-performance 6082 alloy prepared in the following examples are as follows: Wear resistance: A sliding friction and wear test was conducted on the aluminum alloys of the examples and comparative examples, and the wear loss was measured under the test conditions of constant speed (400 rpm) and constant load (7 N).

[0021] Tensile strength: The aluminum alloys of the examples and comparative examples were tested in strict accordance with GB / T 16865-2013. Both ends of the test piece were clamped with a tensile clamp and placed in a testing machine. The test machine stretched both ends of the test piece. Each example was tested three times, and the average value was taken.

[0022] Example 1; (1) Aluminum chloride hexahydrate and lanthanum nitrate were mixed in a mass ratio of 10:1 to obtain a mixture, water was added, the ratio of the mixture to water was 1g:5mL, after stirring at 200rpm for 15min, 2g / 100mL sodium carbonate solution was added at 500rpm and 60℃ at 1mL / min, the total cations in the mixture were: CO3 2-The molar ratio is 1:1.8, stirred for 2 hours, and after the stirring is completed, it is allowed to stand, cooled naturally to 20 ° C, and continued to stand for 3 hours, filtered, washed with ethanol 5 times, aged at 60 ° C for 10 hours, heated to 90 ° C, dried for 4 hours, and the particles are taken out and transferred to a porcelain boat. They are placed in a muffle furnace for calcination, heated to 400 ° C at 5 ° C / min, kept for 4 hours, heated to 800 ° C at 5 ° C / min, kept for 6 hours, and then the heat preservation is ended. When the temperature of the muffle furnace is reduced to room temperature, nitrogen is purged and replaced, and nitrogen gas is used. The mixture was heated at a rate of 100 mL / min for 0.5 h. After the nitrogen was replaced, the nitrogen was turned off and hydrogen was turned on for 0.5 h. After the hydrogen replacement was completed, the hydrogen flow rate was increased to 300 mL / min. At the same time, the heating program of the tubular furnace was started. The specific program was to increase the temperature to 300 ° C. at a rate of 5 ° C / min and maintain for 2 h. After the insulation was completed, the hydrogen was turned off and replaced with nitrogen at a rate of 100 mL / min for 0.5 h to obtain aluminum-rare earth alloy powder. (2) Prepare aluminum alloy raw materials according to the following weight ratio: Si0.95%, Mg1.2%, Cu0.1%, Mn0.5%, Cr0.13%, Ti0.11%, Zn≤0.05%, other individual impurities≤0.03%, total impurities≤0.10%, and the balance Al. Add the prepared aluminum alloy raw materials into a melting furnace, mix them evenly, and then melt them into liquid aluminum alloy at a melting temperature of 700~750℃. Then add aluminum-rare earth alloy powder, and the mass ratio of aluminum-rare earth alloy powder to liquid aluminum alloy is 1:5. After electromagnetic stirring and mixing for 30 minutes, rapidly cool at a cooling rate of 20℃ / min to obtain aluminum alloy material. (3) A five-element alloy system is composed of aluminum as the matrix, 4% magnesium, 3% lithium, 0.5% titanium and 0.2% scandium by mass, and the rest is pure aluminum. The metal raw materials are mixed according to the mass ratio and melted in a vacuum induction melting furnace under argon protection with a vacuum degree of 0.5×10 -3 Pa, controlling the melt temperature at 800°C and keeping it warm for 20 minutes, introducing high-purity argon gas for protection throughout the process, with an argon flow rate of 15 L / min to suppress the volatilization of lithium elements; adding potassium fluorotitanate and potassium fluoroborate in a molar ratio of 1:2 into the melt, with the total addition amount of the potassium fluorotitanate and potassium fluoroborate mixed salt being 0.8% of the melt mass, during which electromagnetic stirring was carried out at 300 rpm to obtain an alloy melt; (4) The aluminum alloy material was heat treated at 500 ° C for 2 h, and the alloy melt, 3 wt% of the alloy melt silicon carbide particles with a particle size of 3 μm, and 8 wt% of the alloy melt graphene with a particle size of 5 μm were uniformly mixed, and sprayed on the surface of the aluminum alloy material with a thickness of 5 μm under the conditions of argon working intensity of 3 MPa and spray gun speed of 10 mm / s; (5) A gas quenching furnace is used for rapid cooling to room temperature. The gas used in the gas quenching furnace is a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The cooling rate is 20℃ / min. Then, heat treatment is carried out at 500℃ for 2h in a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The above steps are repeated once, and then aging strengthening is carried out: first, it is kept at 120℃ for 8h, then treated at 200℃ for 12h, and then cooled to 170℃ with the furnace and kept at this temperature for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material. After cooling to 100℃ with the furnace, it is switched to forced air cooling and continued to cool to room temperature. The wind speed is adjusted to 2m / s to achieve controllable convection heat exchange. The workpiece is removed when the temperature drops below 50℃ to obtain high-performance 6082 alloy.

[0023] Example 2: (1) Aluminum nitrate nine hydrate and lanthanum chloride hexahydrate were mixed in a mass ratio of 30:1 to obtain a mixture, water was added, the mixture and water ratio was 1g:5mL, after stirring at 200rpm for 15min, 6g / 100mL sodium carbonate solution was added at 500rpm and 70℃ at 3mL / min, the total cations in the mixture were: CO3 2- The molar ratio was 1:2, stirred for 3 hours, and after the stirring was completed, the mixture was allowed to stand, cooled naturally to 20°C, and continued to stand for 4 hours, filtered, washed with ethanol 5 times, aged at 70°C for 10 hours, heated to 100°C, and dried for 4 hours. The particles were taken out and transferred to a porcelain boat, and placed in a muffle furnace for calcination. The temperature was raised to 500°C at 5°C / min and maintained for 2 hours. The temperature was raised to 900°C at 5°C / min and maintained for 4 hours. The heat preservation was then terminated. The temperature of the muffle furnace was lowered to room temperature, and nitrogen was purged and replaced. The nitrogen gas rate was 0.05. 100mL / min, purge for 0.5h, after the purge is completed, turn off the nitrogen, start hydrogen purge, the hydrogen flow rate is 100mL / min, purge for 0.5h, after the hydrogen replacement is completed, increase the hydrogen flow rate to 300mL / min, and at the same time start the heating program of the tubular furnace, specifically 5℃ / min to 400℃, hold for 3h, turn off the hydrogen and switch to nitrogen after the insulation is completed, the nitrogen flow rate is 100mL / min, purge for 0.5h, and obtain aluminum-rare earth alloy powder; (2) Prepare aluminum alloy raw materials according to the following weight ratio: Si 1.0%, Mg 1.1%, Cu 0.15%, Mn 0.9%, Cr 0.18%, Ti 0.15%, Zn ≤ 0.05%, other individual impurities ≤ 0.03%, total impurities ≤ 0.10%, and the balance is Al. Add the prepared aluminum alloy raw materials into a melting furnace, mix them evenly, and then melt them into liquid aluminum alloy at a melting temperature of 700-750 °C. Then add aluminum-rare earth alloy powder, and the mass ratio of aluminum-rare earth alloy powder to liquid aluminum alloy is 1:20. After electromagnetic stirring and mixing for 20 minutes, rapidly cool at a cooling rate of 20 °C / min to obtain aluminum alloy material. (3) A five-element alloy system is composed of aluminum as the matrix, 5% magnesium, 4% lithium, 0.75% titanium and 0.35% scandium by mass, and the rest is pure aluminum. The metal raw materials are mixed according to the mass ratio and melted in a vacuum induction melting furnace under argon protection with a vacuum degree of 0.5×10 -3 Pa, controlling the melt temperature at 825°C and keeping it warm for 25 minutes, introducing high-purity argon gas for protection throughout the process, with an argon flow rate of 17.5 L / min to suppress the volatilization of lithium elements; adding potassium fluorotitanate and potassium fluoroborate into the melt in a molar ratio of 1:2, with the total addition amount of the potassium fluorotitanate and potassium fluoroborate mixed salt being 1.0% of the melt mass, during which electromagnetic stirring was performed at 300 rpm to obtain an alloy melt; (4) The aluminum alloy material was heat treated at 530 ° C for 2 h, and the alloy melt, 3 wt% of the alloy melt silicon carbide particles with a particle size of 3 μm, and 8 wt% of the alloy melt graphene with a particle size of 5 μm were uniformly mixed, and sprayed on the surface of the aluminum alloy material under the conditions of argon working intensity of 3 MPa and spray gun speed of 10 mm / s, with a thickness of 5 μm; (5) A gas quenching furnace is used for rapid cooling to room temperature. The gas used in the gas quenching furnace is a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The cooling rate is 20℃ / min. Then, heat treatment is carried out at 530℃ for 2h in a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The above steps are repeated once, and then aging strengthening is carried out: first, it is kept at 120℃ for 8h, then treated at 200℃ for 12h, and then cooled to 170℃ with the furnace and kept at this temperature for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material. After cooling to 100℃ with the furnace, it is switched to forced air cooling and continued to cool to room temperature. The wind speed is adjusted to 2m / s to achieve controllable convection heat exchange. The workpiece is removed when the temperature drops below 50℃ to obtain high-performance 6082 alloy.

[0024] Example 3; (1) Aluminum nitrate nine hydrate and lanthanum nitrate were mixed in a mass ratio of 30:1 to obtain a mixture, water was added, the mixture and water ratio was 1g:10mL, after stirring at 200rpm for 15min, 10g / 100mL sodium carbonate solution was added at 500rpm and 80℃ at 5mL / min, the total cations in the mixture were: CO3 2-The molar ratio is 1:2.2, stirred for 4 hours, and after the stirring is completed, it is allowed to stand, cooled naturally to 30°C, and continued to stand for 3-6 hours, filtered, washed with ethanol 5 times, aged at 80°C for 12 hours, heated to 120°C, dried for 4-6 hours, and the particles are taken out and transferred to a porcelain boat. They are placed in a muffle furnace for calcination, heated to 600°C at 5°C / min, maintained for 3 hours, heated to 1000°C at 5°C / min, maintained for 4 hours, and then the heat preservation is terminated. When the temperature of the muffle furnace is reduced to room temperature, nitrogen is purged and replaced. The nitrogen flow rate was 100 mL / min, and the purge was continued for 0.5 h. After the purge was completed, the nitrogen was turned off and the hydrogen flow rate was turned on for 0.5 h. After the hydrogen replacement was completed, the hydrogen flow rate was increased to 300 mL / min. At the same time, the heating program of the tubular furnace was started. The specific program was to increase the temperature to 500 ° C. at 5 ° C / min and maintain for 3 h. After the insulation was completed, the hydrogen was turned off and replaced with nitrogen at a nitrogen flow rate of 100 mL / min for 0.5 h to obtain aluminum-rare earth alloy powder; (2) Prepare aluminum alloy raw materials according to the following weight ratio: Si 1.1%, Mg 0.9%, Cu 0.05%, Mn 0.9%, Cr 0.15%, Ti 0.15%, Zn ≤ 0.05%, other individual impurities ≤ 0.03%, total impurities ≤ 0.10%, and the balance Al. Add the prepared aluminum alloy raw materials into a melting furnace, mix them evenly, and then melt them into liquid aluminum alloy at a melting temperature of 750 °C. Then add aluminum-rare earth alloy powder, and the mass ratio of aluminum-rare earth alloy powder to liquid aluminum alloy is 1:20. After electromagnetic stirring and mixing for 20 minutes, rapidly cool at a cooling rate of 20 °C / min to obtain aluminum alloy material. (3) A five-element alloy system is formed with aluminum as the matrix, and the mass ratio of magnesium, lithium, titanium, and scandium is 6%, 5%, and the rest is pure aluminum. The metal raw materials are mixed according to the mass ratio and melted in a vacuum induction melting furnace under argon protection. The vacuum degree is 0.5×10 -3 Pa, controlling the melt temperature at 850°C and keeping it warm for 30 minutes, introducing high-purity argon gas for protection throughout the process at a flow rate of 20 L / min to suppress the volatilization of lithium elements; adding potassium fluorotitanate and potassium fluoroborate into the melt in a molar ratio of 1:2, with the total addition amount of the potassium fluorotitanate and potassium fluoroborate mixed salt being 1.2% of the melt mass, during which electromagnetic stirring was performed at 300 rpm to obtain an alloy melt; (4) The aluminum alloy material was heat treated at 570 ° C for 3 h, and the alloy melt, 3 wt% of the alloy melt silicon carbide particles with a particle size of 3 μm, and 8 wt% of the alloy melt graphene with a particle size of 5 μm were uniformly mixed. Under the conditions of argon working intensity of 3 MPa and spray gun speed of 10 mm / s, the mixture was sprayed on the surface of the aluminum alloy material to a thickness of 5 μm. (5) A gas quenching furnace is used for rapid cooling to room temperature. The gas used in the gas quenching furnace is a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The cooling rate is 20℃ / min. Then, heat treatment is carried out at 570℃ for 3h in a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.5. The above steps are repeated twice, and then aging strengthening is carried out: first, it is kept at 120℃ for 8h, then treated at 200℃ for 12h, and then cooled to 170℃ with the furnace and kept at this temperature for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material. After cooling to 100℃ with the furnace, it is switched to forced air cooling and continued to cool to room temperature. The wind speed is adjusted to 2m / s to achieve controllable convection heat exchange. The workpiece is removed when the temperature drops below 50℃ to obtain high-performance 6082 alloy.

[0025] Comparative Example 1: The difference between Comparative Example 1 and Example 2 lies in the difference in step (3). Step (3) is changed to: using aluminum as the matrix, the mass ratio of 5% magnesium, 0.75% titanium and 0.35% scandium, and the rest being pure aluminum, to form a five-element alloy system; the metal raw materials are mixed according to the mass ratio, and melted in a vacuum induction melting furnace under argon protection, with a vacuum degree of 0.5×10 -3 Pa, controlling the melt temperature at 825° C. and keeping it warm for 25 min, introducing high-purity argon gas for protection throughout the process, with an argon flow rate of 17.5 L / min, adding potassium fluorotitanate and potassium fluoroborate into the melt in a molar ratio of 1:2, and adding the total amount of the mixed salt of potassium fluorotitanate and potassium fluoroborate to the melt is 1% of the mass of the melt, during which electromagnetic stirring is carried out at 350 rpm to obtain an alloy melt; the remaining steps are the same as those in Example 2.

[0026] Comparative Example 2: The difference between Comparative Example 2 and Example 2 lies in the difference in step (3). Step (3) is changed to: using aluminum as the matrix, the mass ratio of 5% magnesium, 4% lithium, 0.75% titanium and 0.35% scandium, and the rest being pure aluminum, to form a five-element alloy system; the metal raw materials are mixed according to the mass ratio, and melted in a vacuum induction melting furnace under argon protection, with a vacuum degree of 0.5×10 -3 Pa, control the melt temperature at 825°C and keep it warm for 25 minutes, introduce high-purity argon protection throughout the process, and the argon flow rate is 17.5 L / min to suppress the volatilization of lithium elements to obtain an alloy melt; the remaining steps are the same as those in Example 2.

[0027] Comparative Example 3; The difference between Comparative Example 3 and Example 2 is that no aluminum-rare earth alloy powder is added to the liquid aluminum alloy, and the remaining steps are the same as Example 2.

[0028] Comparative Example 4: The difference between Comparative Example 4 and Example 2 lies in the difference in step (5). Step (5) is changed to: rapid cooling to room temperature at a cooling rate of 20°C / min, heat treatment at 530°C for 2h, repeating the above steps once, and then performing aging strengthening: first keeping warm at 120°C for 8h, then treating at 200°C for 12h, and then cooling to 170°C with the furnace and keeping warm for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material; after cooling to 100°C with the furnace, it is switched to forced air cooling and continued to cool to room temperature. By adjusting the wind speed to 2m / s, controllable convection heat exchange is achieved. The workpiece is removed when the temperature drops below 50°C to obtain a high-performance 6082 alloy.

[0029] Effect Examples Table 1 below shows the performance analysis results of a high performance 6082 alloy using Examples 1 to 3 of the present invention and Comparative Examples 1 to 4.

[0030] Table 1 The present invention utilizes water-soluble aluminum salts and rare earth salts, combined with sodium carbonate precipitation and stirring, to prepare uniformly dispersed rare earth carbonates in aluminum hydroxide. After calcination and reduction, aluminum powder reinforced with fine-grained rare earth oxides is obtained. Compared with traditional mechanical alloying, it has smaller and more uniform particles, avoiding wear pollution and oxidation. Adding aluminum-rare earth alloy powder to the 6082 alloy melt can improve the mechanical properties of the alloy, refine the grains, and reduce oxide aggregation. Through stirring and rapid cooling, uniform dispersion and precipitation of nano-oxides are achieved, improving material performance and safety. In addition, nano-silicon carbide and graphene are introduced on the surface to impart self-lubricating and wear-resistant properties, and are treated with a mixed atmosphere of nitrogen and ammonia to form a gradient structure layer, further optimizing friction resistance and mechanical properties.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing high-performance 6082 alloy, characterized in that: The method comprises the following preparation steps: (1) Aluminum salt and rare earth salt are mixed in a mass ratio of 10-50:1 to obtain a mixture, water is added, and after stirring for 15 minutes, sodium carbonate solution is added at 60-80 ° C. The total cations in the mixture are: CO3 2- The molar ratio is 1:1.8-2.2, and the mixture is stirred for 2-4 hours. After the stirring is completed, the mixture is allowed to stand, cooled, filtered, washed, and then transferred to a porcelain boat and placed in a muffle furnace for calcination to obtain aluminum-rare earth alloy powder; (2) Prepare aluminum alloy raw materials according to the following weight ratio: Si 0.95-1.1%, Mg 0.9~1.2%, Cu 0.05-0.15%, Mn 0.4~0.9%, Cr 0.13~0.18%, Ti 0.11~0.18%, Zn ≤ 0.05%, other individual impurities ≤ 0.03%, total impurities ≤ 0.10%, and the balance is Al. Add the prepared aluminum alloy raw materials into a melting furnace, mix them evenly, and then melt them into liquid aluminum alloy at a melting temperature of 700~750℃. Then add aluminum-rare earth alloy powder, stir and mix for 5min~60min, and then quickly cool to obtain aluminum alloy material; (3) Mixing the metal raw materials according to the mass ratio and smelting them under argon protection; adding potassium fluorotitanate and potassium fluoroborate into the melt, and performing electromagnetic stirring during the process to obtain an alloy melt; (4) The aluminum alloy material is heat treated at 500-570℃ for 2-3h, and the alloy melt, silicon carbide particles accounting for 3wt% of the alloy melt, and graphene accounting for 8wt% of the alloy melt are uniformly mixed. Under the conditions of argon working intensity of 3MPa and spray gun speed of 10mm / s, the mixture is sprayed on the surface of the aluminum alloy material to a thickness of 5-10μm. (5) A gas quenching furnace is used for rapid cooling to room temperature. The gas used in the gas quenching furnace is a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.

5. The cooling rate is 20℃ / min. Then, heat treatment is carried out at 500-570℃ for 2-3h in a mixed gas with a volume ratio of argon, nitrogen, and ammonia of 10:1:0.

5. The above steps are repeated 1-2 times, and then aging strengthening is carried out: first, it is kept at 120℃ for 8h, then treated at 200℃ for 12h, and then cooled to 170℃ with the furnace and kept at this temperature for 6h. During this process, the inert gas in the furnace is kept to protect the environment to prevent oxidation of the material. After cooling to 100℃ with the furnace, it is switched to forced air cooling and continued to cool to room temperature. The wind speed is adjusted to achieve controllable convection heat exchange. The workpiece is removed when the temperature drops below 50℃ to obtain high-performance 6082 alloy.

2. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The ratio of the mixture to water in step (1) is 1 g: (2-10) mL.

3. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The concentration of the sodium carbonate solution in step (1) is 1-10 g / 100 mL.

4. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: In step (2), the mass ratio of the aluminum-rare earth alloy powder to the liquid aluminum alloy is 1:5-50.

5. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The mass ratio of the metal raw materials in step (3) is: aluminum as the matrix, with a mass ratio of 4-6% magnesium, 3-5% lithium, 0.5-1% titanium and 0.2-0.5% scandium, and the rest is pure aluminum, forming a five-element alloy system.

6. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The melting parameters in step (3) are: vacuum degree of 0.5×10 -3 Pa, control the melt temperature at 800-850℃ and keep it warm for 20-30min, and introduce high-purity argon protection throughout the process with an argon flow rate of 15-20L / min to suppress the volatilization of lithium elements.

7. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: In step (3), the total amount of the mixed salt of potassium fluorotitanate and potassium fluoroborate added is 0.8-1.2% of the mass of the melt.

8. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The molar ratio of potassium fluorotitanate to potassium fluoroborate in step (3) is 1:

2.

9. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: In step (4), the particle size of the silicon carbide particles is 3 μm and the particle size of the graphene is 5 μm.

10. The method for preparing a high performance 6082 alloy according to claim 1, characterized in that: The wind speed in step (5) is 2-3 m / s.

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