High-strength corrosion-resistant aluminum alloy extrusion material and method for manufacturing the same

Abstract

The application discloses a kind of high-strength corrosion-resistant aluminum alloy extruded materials and preparation method thereof, it is related to novel aviation aluminum alloy material technical field.The method first melts high-purity aluminum and adds Si, Fe, Cu, Mn, Cr, Zn, Ti and Mg for alloying;Ti-B-C nano intermediate alloy, Sc, Zr, lanthanum-rich mixed rare earth and acicular nanowollastonite are introduced into the melt, and high-energy ultrasonic and pulse magnetic field are applied for collaborative processing, to realize in-situ generation and uniform dispersion of nano phase;After semi-continuous casting, it is carried out segmented homogenization heat treatment, and then formed by hot extrusion;Finally, the extruded profile is sequentially subjected to solid solution quenching, low-temperature pre-aging, and pulse electric field is applied in atmosphere furnace for auxiliary, Yb-Ce rare earth precursor and silane modified nano SiO2 are introduced for grain boundary regulation and passivation treatment.The aluminum alloy extruded material of the application has ultra-high mechanical properties and excellent corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of novel aerospace aluminum alloy materials technology, specifically to a high-strength corrosion-resistant aluminum alloy extrusion material and its preparation method. Background Technology

[0002] With the rapid iteration and upgrading of the global aerospace industry, high-end equipment such as new-generation civil large aircraft, military combat aircraft, and near-space vehicles have placed increasingly stringent core requirements on lightweight structures, high load-bearing reliability, and long service life. Aluminum alloys, as the most widely used and technologically mature lightweight metal structural material in the aerospace field, occupy an irreplaceable position in core aerospace structural components such as fuselage load-bearing frames, wing ribs, landing gear auxiliary load-bearing structures, airborne equipment mounting beams, cabin sealing connections, and aero-engine peripheral components due to their low density, high specific strength, excellent cold and hot forming performance, good weldability, and environmentally friendly characteristics of being recyclable throughout its entire life cycle. Among them, Al-Mg-Si series (6000 series) aluminum alloys, due to their excellent heat treatment strengthening effect, complex cross-section extrusion formability, and balanced advantages of moderate strength and basic corrosion resistance, have become the preferred base material for medium-to-high strength thin-walled, irregularly shaped cross-section extruded structural components in the new aerospace aluminum alloy material system, and are currently a hot topic in the research and industrial application of lightweight aerospace materials globally. However, existing Al-Mg-Si aluminum alloys used in the aerospace field still have shortcomings in core performance. Their mechanical strength and corrosion resistance are insufficient to meet the stringent requirements of next-generation aerospace equipment, leaving significant room for improvement. In terms of mechanical strength, the aerospace-grade aluminum alloys currently used in large-scale applications in the aerospace field lack sufficient strength and can only be used for non-load-bearing interior parts and auxiliary structural components, failing to meet the high-strength requirements of main load-bearing structural components in aerospace applications. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength, corrosion-resistant aluminum alloy extrusion material and its preparation method, thereby solving the technical problems mentioned in the background section. The aluminum alloy extrusion material prepared by this invention possesses both excellent mechanical strength and corrosion resistance.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0006] (1) Melt high-purity aluminum ingots, add high-purity Si, high-purity Fe, high-purity Cu, high-purity Mn, high-purity Cr, high-purity Zn and high-purity Ti in sequence, keep warm and stir until completely melted, then add sodium-free refining agent for refining, degassing and slag removal, add high-purity Mg after refining, keep warm and stir until completely melted, let stand and remove surface slag to obtain aluminum melt;

[0007] (2) Add Ti-BC nano-intermediate alloy, high-purity metal Sc, high-purity metal Zr, lanthanum-rich mixed rare earth and needle-shaped nano-wollastonite to the aluminum melt, and then apply high-energy ultrasound and pulsed magnetic field treatment. Control the melt temperature during the treatment process, keep it warm and stand after the treatment is completed, and remove the surface slag.

[0008] (3) After cooling the melt obtained in step (2), semi-continuous casting is carried out to obtain an ingot. After air cooling, the head and tail risers and surface segregation layer of the ingot are removed. The ingot is subjected to segmented heating and heat preservation heat treatment, forced air cooling, and then sawn into extrusion billets. After heating, hot extrusion is carried out in a preheated extrusion cylinder and extrusion die. The extrusion outlet profile is cooled online to obtain the extrusion profile.

[0009] (4) The extruded profile is solution treated, kept warm and then water quenched, then pre-aged at low temperature, kept warm and then cooled in the furnace.

[0010] (5) The profile obtained in step (4) is placed in an atmosphere heat treatment furnace, high-purity argon is introduced, and Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and silane modified nano SiO2 aerosol are introduced. A pulsed electric field is applied, and the material is kept warm. Then, after heating and holding and cooling, a high-strength corrosion-resistant aluminum alloy extruded material is obtained.

[0011] In the technical solution of this invention, (1) the mechanical strength of aluminum alloy extrusion materials is improved in synergy from the following aspects: In the melt stage, high-energy ultrasound and longitudinal focused pulse magnetic field are used to disperse the agglomeration of nanoparticles by ultrasonic cavitation effect, and controllable electromagnetic stirring is used to uniformly disperse the modified elements, and in-situ TiB2-TiC composite nano-ceramic phase with a dispersion of 20-50nm is generated to achieve stable second phase strengthening. At the same time, Sc and Zr elements are dissolved in the aluminum matrix without segregation, laying a good foundation for subsequent precipitation strengthening. In the subsequent homogenization heat treatment, high-density Al3(Sc,Zr) nano-phases that are completely coherent with the aluminum matrix are precipitated in-situ in the low temperature section, and fine grain strengthening is achieved by pinning the cast grain boundaries; in the medium temperature section, the cast dendritic segregation is completely eliminated and the non-equilibrium eutectic phase is dissolved to ensure uniform structure while avoiding coarsening of nano-phase; in the high temperature section, in a safe range far below the alloy overheating temperature, the main strengthening elements Mg and Si are fully dissolved to maximize the solid solution strengthening effect. Finally, the dynamic recrystallization of the hot extrusion process further refines the grains. Through the multi-dimensional synergy of second phase strengthening, grain refinement strengthening, precipitation strengthening and solid solution strengthening, the mechanical strength of aluminum alloy is greatly improved from the root of the structure. (2) The corrosion resistance of aluminum alloy extrusion materials is improved in the following ways: First, through low temperature pre-aging, a high-density and uniformly distributed nano-strengthening phase is formed in the grain, which completely locks the ultra-high strength obtained above and avoids the strength decay in the subsequent corrosion resistance control process; then, through the strong pulse electric field assisted rare earth grain boundary segregation control, the diffusion activation energy of solute atoms is greatly reduced by the electric field electromigration effect, so that Yb-Ce rare earth elements preferentially diffuse and segregate rapidly along the grain boundary of the profile surface (the core area of ​​corrosion initiation), filling the grain boundary vacancies and defects on the one hand, and eliminating the Cu element enrichment difference between the grain boundary and the grain on the other hand, and reducing the electrochemical potential of the two. By controlling the voltage difference within 15mV, the electrochemical reaction driving force of grain boundary corrosion is eliminated. At the same time, by utilizing the surface adsorption effect of rare earth elements, the originally continuous network precipitates at the grain boundaries are transformed into discrete spherical structures, initially blocking the expansion channels of intergranular corrosion. Finally, through medium-temperature heat preservation, silane-modified nano-SiO2 is chemically bonded to the aluminum matrix and segregated rare earth elements at the grain boundaries, forming a dense, continuous, and self-healing Al-Si-O-RE passivation film in situ. This completely seals the grain boundary corrosion channels, ultimately achieving a comprehensive improvement in the aluminum alloy's resistance to intergranular corrosion, exfoliation corrosion, and long-term salt spray resistance.

[0012] Preferably, in step (2), the amount of Ti-BC nano-intermediate alloy added is 0.3% to 0.8% of the mass of the aluminum melt.

[0013] Preferably, in step (2), the molar ratio of Ti:B:C in the Ti-BC nano-intermediate alloy is 3:2:1, and the particle size of the powder is 50-100 nm.

[0014] Preferably, in step (2), the amount of high-purity metal Sc added is 0.05% to 0.15% of the mass of the aluminum melt.

[0015] Preferably, in step (2), the amount of high-purity metal Zr added is 0.08% to 0.20% of the mass of the aluminum melt.

[0016] Preferably, in step (2), the mass ratio of lanthanum-rich mixed rare earth to needle-shaped nano-wollastonite is 1:(1.5-3.0).

[0017] In experiments, this invention discovered that while the TiB2-TiC composite nano-ceramic phase and Al3(Sc,Zr) nano-precipitates introduced to enhance mechanical strength can significantly improve material strength through multiple synergistic mechanisms, the inherent electrochemical potential difference between these second phases and the aluminum matrix can lead to the formation of numerous localized corrosion micro-cells as micro-cathodes in corrosive service environments. This not only directly negates the grain boundary regulation and passivation protection effects of corrosion resistance modification but also becomes a new initiation site for pitting and intergranular corrosion. Ultimately, this results in a strong contradiction between achieving the required material strength but a sharp increase in the risk of localized corrosion. Furthermore, reducing the content of the nano-reinforcing phase to alleviate corrosion problems directly weakens the strengthening effect on mechanical strength, making it impossible to achieve a stable and synergistic improvement in material strength and corrosion resistance. To address this technical problem, this invention introduces lanthanum-rich mixed rare earth elements and needle-shaped nano-wollastonite simultaneously during the in-situ melt synthesis step. These elements work synergistically through interfacial potential regulation and structural stabilization passivation to resolve the aforementioned issues. The La and Ce elements in the lanthanum-rich mixed rare earth elements, due to their extremely high surface activity, preferentially adsorb at the solid-liquid interface of the TiB2-Ti nano-ceramic phase during the in-situ melt synthesis process, forming a uniform rare earth coating layer. This reduces the interfacial energy between the ceramic phase and the aluminum matrix, enhances the interfacial bonding strength to assist in strengthening the material's mechanical properties, and significantly reduces the electrochemical potential difference between the nano-reinforcing phase and the aluminum matrix through the electronic regulation of rare earth elements, fundamentally addressing the formation basis of micro-cells in localized corrosion. Meanwhile, the needle-shaped nano-wollastonite, with its needle-like structure, forms dislocation pinning and bridging effects in the aluminum matrix, further enhancing the toughening effect. Simultaneously, it serves as a nucleation core for the passivation film during the passivation film formation step, promoting the continuous growth of the Al-Si-O-RE passivation film at the nano-reinforcing phase interface, thoroughly filling the weak corrosion sites at the interface and blocking the path of localized corrosion initiation.

[0018] Preferably, in step (4), the solution treatment temperature is 540-550℃ and the solution treatment time is 20-30 min.

[0019] Preferably, in step (5), the mass ratio of the Yb(acac)3-Ce(acac)3 composite rare earth organic precursor to the silane-modified nano-SiO2 aerosol is 1:(1.5~3.0).

[0020] Preferably, in step (5), the mass ratio of Yb to Ce in the Yb(acac)3-Ce(acac)3 composite rare earth organic precursor is 2:1.

[0021] A high-strength, corrosion-resistant aluminum alloy extrusion material is prepared by the method described above.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. By combining in-situ melt synthesis and gradient homogenization heat treatment, and by comprehensively utilizing second-phase strengthening (generating dispersed nano-ceramic phases), fine-grain strengthening (precipitating coherent nano-phases to pin grain boundaries), precipitation strengthening and solid solution strengthening, and by combining hot extrusion dynamic recrystallization, a leapfrog improvement in the mechanical properties of aluminum alloys has been achieved from the root of the microstructure.

[0024] 2. By employing a synergistic process of low-temperature pre-aging to lock strength, electric field-assisted rare earth grain boundary segregation, and in-situ generation of passivation film, the potential difference between grain boundaries and grains is effectively eliminated, intergranular corrosion channels are blocked, and a dense passivation film with self-healing capabilities is generated, achieving a comprehensive improvement in resistance to intergranular corrosion, exfoliation corrosion, and salt spray.

[0025] 3. To address the technical challenge of localized corrosion caused by nano-reinforced phases, lanthanum-rich mixed rare earth elements and needle-like nano-wollastonite are introduced simultaneously. The rare earth coating layer is used to regulate the interface potential to eliminate the micro-cell effect, and wollastonite is used to promote the continuous growth of the passivation film at the interface of the reinforced phase, ultimately achieving a stable and synergistic improvement in material strength and corrosion resistance. Attached Figure Description

[0026] Figure 1 This is a low-magnification SEM image of the surface of the aluminum alloy extruded material prepared in Example 4 of the present invention.

[0027] Figure 2 This is a medium-magnification SEM image of the surface of the aluminum alloy extruded material prepared in Example 4 of the present invention.

[0028] Figure 3 This is a high-magnification SEM image of the surface of the aluminum alloy extruded material prepared in Example 4 of the present invention.

[0029] Figure 4 This is a surface morphology image of the aluminum alloy extruded material prepared in Example 4 of the present invention after EXCO corrosion for 48 hours.

[0030] Figure 5 This is a surface morphology image of the aluminum alloy extruded material prepared in Comparative Example 2 of the present invention after EXCO corrosion for 48 hours. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0032] The Ti-BC nano-master alloy used in this application is a commercially available industrial-grade nano-master alloy with the product designation AlTi3B2C1. The molar ratio of Ti, B, and C elements in this product is 3:2:1, the average particle size of the powder is 70 nm, and the particle size distribution range is 50–100 nm.

[0033] Example 1

[0034] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0035] Step 1: Place 10 kg of industrial high-purity aluminum ingots with a purity ≥ 99.95% into a medium-frequency induction melting furnace, heat to 740℃ until the aluminum ingots are completely melted, and add the following components in the following proportions: 110 g of high-purity industrial Si (purity ≥ 99.95%), 10 g of high-purity industrial Fe (purity ≥ 99.95%), 20 g of high-purity industrial Cu (purity ≥ 99.95%), 35 g of high-purity industrial Mn (purity ≥ 99.95%), 12 g of high-purity industrial Cr (purity ≥ 99.95%), 5 g of high-purity industrial Zn (purity ≥ 99.95%), and 1 g of high-purity industrial Ti. Add 4g of high-purity Mg (purity ≥99.95%), heat and stir for 20 minutes until all alloying elements are completely melted. Then add 20g of sodium-free refining agent and use argon gas rotary blowing to refine, degas and remove slag. The argon gas flow rate is controlled at 0.4L / min and the refining time is 20 minutes. After refining, add 130g of high-purity Mg (purity ≥99.95%), heat and stir for 5 minutes until completely melted. After standing for 15 minutes, thoroughly remove the slag on the surface of the melt to obtain pure aluminum melt.

[0036] Step 2: Add 70g of Ti-BC nano-master alloy, 12g of high-purity industrial metal Sc (purity ≥99.95%), 18g of high-purity industrial metal Zr (purity ≥99.95%), 10g of industrial-grade lanthanum-rich mixed rare earth, and 25g of needle-shaped nano-wollastonite to the 10kg aluminum melt prepared above. The Ti:B:C molar ratio in the Ti-BC nano-master alloy is 3:2:1, and the powder particle size is 50-100nm. Immediately afterwards, use a special processing equipment with a closed-loop water-cooled temperature control system to apply high-energy ultrasonic treatment with a power of 1000W and a frequency of 20kHz for 10 minutes. Only the end 15mm of the titanium alloy amplitude transformer is immersed in the melt, and a longitudinal focused pulsed magnetic field with a magnetic induction intensity of 1.2T and a frequency of 15Hz is applied simultaneously for 15 minutes. During the treatment, the melt temperature is stably controlled at 740±3℃ through closed-loop temperature control. After the treatment is completed, keep it at the temperature for 10 minutes and remove the trace amount of slag on the surface of the melt.

[0037] Step 3: Cool the processed melt to 720℃ and prepare ingots using a small semi-continuous casting machine with a graphite lubricated crystallizer. Set the casting speed to 80mm / min, the cooling water pressure to 0.3MPa, and the cooling water flow rate to 1.2m³ / min. 3 The ingots, with dimensions of Φ120mm × 300mm, were air-cooled to room temperature after casting. Then, 30mm of risers at both ends of the ingot were removed using a lathe, and the surface segregation layer was machined to a thickness of 3mm on one side. The treated ingots were then placed in a programmable temperature-controlled box-type heat treatment furnace. The furnace was first heated to 350℃ at a rate of 80℃ / h and held for 7 hours, then heated to 470℃ at a rate of 50℃ / h and held for 10 hours, and finally heated to 555℃ at a rate of 30℃ / h and held for 12 hours. The ingots were removed immediately after the holding period. Forced air cooling to room temperature at a cooling rate of 260℃ / h was applied, followed by sawing of the ingot into 180mm long extrusion blanks. The blanks were then placed in a resistance heating furnace and heated to 490℃ for 2 hours. Simultaneously, the extrusion cylinder was preheated to 440℃ and the extrusion die was preheated to 480℃. Hot extrusion forming was performed using a 2500t horizontal extrusion press with an extrusion ratio of 30:1. The extruded profile was cooled by online water mist at a cooling rate of ≥30℃ / s, resulting in a rectangular extruded profile with a cross-sectional dimension of 30mm×10mm.

[0038] Step 4: Cut the extruded profile prepared above into standard samples with a length of 200 mm, place them in a well-type solution furnace, and perform solution treatment at 545℃ for 25 min. After the heat treatment, immediately transfer the samples to room temperature water for water quenching. The quenching transfer time is ≤8 s, and the water quenching cooling rate is ≥100℃ / s. After quenching, the sample temperature drops to below 45℃. Then, place the samples in a constant temperature box furnace and perform low temperature pre-aging treatment at 115℃. After heat treatment for 7 h, cool them down to 100℃ with the furnace.

[0039] Step 5: Transfer the processed profiles into an atmosphere heat treatment furnace equipped with a strong pulsed electric field generator. Continuously introduce high-purity argon as the carrier gas, with a flow rate controlled at 0.8 L / min. Simultaneously introduce 10 g of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and 25 g of silane-modified nano-SiO2 aerosol. The mass ratio of Yb to Ce in the composite rare earth organic precursor is 2:1. Apply a strong pulsed electric field with a field strength of 10 kV / cm and a frequency of 80 Hz. Hold at 110℃ for 12 h. During the treatment, maintain a slight positive pressure 50 Pa higher than the standard atmospheric pressure inside the furnace. Control the oxygen content to ≤30 ppm. After the treatment, stop introducing the precursor and the pulsed electric field. Increase the temperature to 150℃ at a rate of 50℃ / h and hold for 4 h. After the holding period, cool with the furnace to room temperature to obtain a high-strength corrosion-resistant aluminum alloy extruded material.

[0040] Example 2

[0041] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0042] Step 1: Place 10 kg of industrial high-purity aluminum ingots with a purity ≥ 99.95% into a medium-frequency induction melting furnace, heat to 740℃ until the aluminum ingots are completely melted, and add the following components in the following proportions: 110 g of high-purity industrial Si (purity ≥ 99.95%), 10 g of high-purity industrial Fe (purity ≥ 99.95%), 20 g of high-purity industrial Cu (purity ≥ 99.95%), 35 g of high-purity industrial Mn (purity ≥ 99.95%), 12 g of high-purity industrial Cr (purity ≥ 99.95%), 5 g of high-purity industrial Zn (purity ≥ 99.95%), and 1 g of high-purity industrial Ti. Add 4g of high-purity Mg (purity ≥99.95%), heat and stir for 20 minutes until all alloying elements are completely melted. Then add 20g of sodium-free refining agent and use argon gas rotary blowing to refine, degas and remove slag. The argon gas flow rate is controlled at 0.4L / min and the refining time is 20 minutes. After refining, add 130g of high-purity Mg (purity ≥99.95%), heat and stir for 5 minutes until completely melted. After standing for 15 minutes, thoroughly remove the slag on the surface of the melt to obtain pure aluminum melt.

[0043] Step 2: Add 50g of Ti-BC nano-master alloy, 8g of high-purity industrial metal Sc (purity ≥99.95%), 10g of high-purity industrial metal Zr (purity ≥99.95%), 10g of industrial-grade lanthanum-rich mixed rare earth, and 18g of needle-shaped nano-wollastonite to the 10kg aluminum melt prepared above. The Ti:B:C molar ratio in the Ti-BC nano-master alloy is 3:2:1, and the powder particle size is 50-100nm. Immediately afterwards, use a special processing equipment with a closed-loop water-cooled temperature control system to apply high-energy ultrasonic treatment with a power of 1000W and a frequency of 20kHz for 10 minutes. Only the end 15mm of the titanium alloy amplitude transformer is immersed in the melt, and a longitudinal focused pulsed magnetic field with a magnetic induction intensity of 1.2T and a frequency of 15Hz is applied simultaneously for 15 minutes. During the treatment, the melt temperature is stably controlled at 740±3℃ through closed-loop temperature control. After the treatment is completed, keep it at the temperature for 10 minutes and remove the trace amount of slag on the surface of the melt.

[0044] Step 3: Cool the processed melt to 720℃ and prepare ingots using a small semi-continuous casting machine with a graphite lubricated crystallizer. Set the casting speed to 80mm / min, the cooling water pressure to 0.3MPa, and the cooling water flow rate to 1.2m³ / min. 3 The ingots, with dimensions of Φ120mm × 300mm, were air-cooled to room temperature after casting. Then, 30mm of risers at both ends of the ingot were removed using a lathe, and the surface segregation layer was machined to a thickness of 3mm on one side. The treated ingots were then placed in a programmable temperature-controlled box-type heat treatment furnace. The furnace was first heated to 350℃ at a rate of 80℃ / h and held for 7 hours, then heated to 470℃ at a rate of 50℃ / h and held for 10 hours, and finally heated to 555℃ at a rate of 30℃ / h and held for 12 hours. The ingots were removed immediately after the holding period. Forced air cooling to room temperature at a cooling rate of 260℃ / h was applied, followed by sawing of the ingot into 180mm long extrusion blanks. The blanks were then placed in a resistance heating furnace and heated to 490℃ for 2 hours. Simultaneously, the extrusion cylinder was preheated to 440℃ and the extrusion die was preheated to 480℃. Hot extrusion forming was performed using a 2500t horizontal extrusion press with an extrusion ratio of 30:1. The extruded profile was cooled by online water mist at a cooling rate of ≥30℃ / s, resulting in a rectangular extruded profile with a cross-sectional dimension of 30mm×10mm.

[0045] Step 4: Cut the extruded profile prepared above into standard samples with a length of 200 mm, place them in a well-type solution furnace, and perform solution treatment at 545℃ for 25 min. After the heat treatment, immediately transfer the samples to room temperature water for water quenching. The quenching transfer time is ≤8 s, and the water quenching cooling rate is ≥100℃ / s. After quenching, the sample temperature drops to below 45℃. Then, place the samples in a constant temperature box furnace and perform low temperature pre-aging treatment at 115℃. After heat treatment for 7 h, cool them down to 100℃ with the furnace.

[0046] Step 5: Transfer the processed profiles into an atmosphere heat treatment furnace equipped with a strong pulsed electric field generator. Continuously introduce high-purity argon as the carrier gas, with a flow rate controlled at 0.8 L / min. Simultaneously introduce 10 g of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and 18 g of silane-modified nano-SiO2 aerosol. The mass ratio of Yb to Ce in the composite rare earth organic precursor is 2:1. Apply a strong pulsed electric field with a field strength of 10 kV / cm and a frequency of 80 Hz. Hold the material at 110℃ for 12 h. During the treatment, maintain a slight positive pressure inside the furnace that is 50 Pa higher than the standard atmospheric pressure. Control the oxygen content to ≤30 ppm. After the treatment, stop introducing the precursor and the pulsed electric field. Increase the temperature to 150℃ at a rate of 50℃ / h and hold for 4 h. After the holding period, cool the material to room temperature with the furnace to obtain a high-strength corrosion-resistant aluminum alloy extruded material.

[0047] Example 3

[0048] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0049] Step 1: Place 10 kg of industrial high-purity aluminum ingots with a purity ≥ 99.95% into a medium-frequency induction melting furnace, heat to 740℃ until the aluminum ingots are completely melted, and add the following components in the following proportions: 110 g of high-purity industrial Si (purity ≥ 99.95%), 10 g of high-purity industrial Fe (purity ≥ 99.95%), 20 g of high-purity industrial Cu (purity ≥ 99.95%), 35 g of high-purity industrial Mn (purity ≥ 99.95%), 12 g of high-purity industrial Cr (purity ≥ 99.95%), 5 g of high-purity industrial Zn (purity ≥ 99.95%), and 1 g of high-purity industrial Ti. Add 4g of high-purity Mg (purity ≥99.95%), heat and stir for 20 minutes until all alloying elements are completely melted. Then add 20g of sodium-free refining agent and use argon gas rotary blowing to refine, degas and remove slag. The argon gas flow rate is controlled at 0.4L / min and the refining time is 20 minutes. After refining, add 130g of high-purity Mg (purity ≥99.95%), heat and stir for 5 minutes until completely melted. After standing for 15 minutes, thoroughly remove the slag on the surface of the melt to obtain pure aluminum melt.

[0050] Step 2: Add 60g of Ti-BC nano-master alloy, 10g of high-purity industrial metal Sc (purity ≥99.95%), 15g of high-purity industrial metal Zr (purity ≥99.95%), 10g of industrial-grade lanthanum-rich mixed rare earth, and 20g of needle-shaped nano-wollastonite to the 10kg aluminum melt prepared above. The Ti:B:C molar ratio in the Ti-BC nano-master alloy is 3:2:1, and the powder particle size is 50-100nm. Immediately afterwards, use a special processing equipment with a closed-loop water-cooled temperature control system to apply high-energy ultrasonic treatment with a power of 1000W and a frequency of 20kHz for 10 minutes. Only the end 15mm of the titanium alloy amplitude transformer is immersed in the melt, and a longitudinal focused pulsed magnetic field with a magnetic induction intensity of 1.2T and a frequency of 15Hz is applied simultaneously for 15 minutes. During the treatment, the melt temperature is stably controlled at 740±3℃ through closed-loop temperature control. After the treatment is completed, keep it at the temperature for 10 minutes and remove the trace amount of slag on the surface of the melt.

[0051] Step 3: Cool the processed melt to 720℃ and prepare ingots using a small semi-continuous casting machine with a graphite lubricated crystallizer. Set the casting speed to 80mm / min, the cooling water pressure to 0.3MPa, and the cooling water flow rate to 1.2m³ / min. 3 The ingots, with dimensions of Φ120mm × 300mm, were air-cooled to room temperature after casting. Then, 30mm of risers at both ends of the ingot were removed using a lathe, and the surface segregation layer was machined to a thickness of 3mm on one side. The treated ingots were then placed in a programmable temperature-controlled box-type heat treatment furnace. The furnace was first heated to 350℃ at a rate of 80℃ / h and held for 7 hours, then heated to 470℃ at a rate of 50℃ / h and held for 10 hours, and finally heated to 555℃ at a rate of 30℃ / h and held for 12 hours. The ingots were removed immediately after the holding period. Forced air cooling to room temperature at a cooling rate of 260℃ / h was applied, followed by sawing of the ingot into 180mm long extrusion blanks. The blanks were then placed in a resistance heating furnace and heated to 490℃ for 2 hours. Simultaneously, the extrusion cylinder was preheated to 440℃ and the extrusion die was preheated to 480℃. Hot extrusion forming was performed using a 2500t horizontal extrusion press with an extrusion ratio of 30:1. The extruded profile was cooled by online water mist at a cooling rate of ≥30℃ / s, resulting in a rectangular extruded profile with a cross-sectional dimension of 30mm×10mm.

[0052] Step 4: Cut the extruded profile prepared above into standard samples with a length of 200 mm, place them in a well-type solution furnace, and perform solution treatment at 545℃ for 25 min. After the heat treatment, immediately transfer the samples to room temperature water for water quenching. The quenching transfer time is ≤8 s, and the water quenching cooling rate is ≥100℃ / s. After quenching, the sample temperature drops to below 45℃. Then, place the samples in a constant temperature box furnace and perform low temperature pre-aging treatment at 115℃. After heat treatment for 7 h, cool them down to 100℃ with the furnace.

[0053] Step 5: Transfer the processed profiles into an atmosphere heat treatment furnace equipped with a strong pulsed electric field generator. Continuously introduce high-purity argon as the carrier gas, with a flow rate controlled at 0.8 L / min. Simultaneously introduce 10 g of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and 20 g of silane-modified nano-SiO2 aerosol. The mass ratio of Yb to Ce in the composite rare earth organic precursor is 2:1. Apply a strong pulsed electric field with a field strength of 10 kV / cm and a frequency of 80 Hz. Hold at 110℃ for 12 h. During the treatment, maintain a slight positive pressure 50 Pa higher than the standard atmospheric pressure inside the furnace. Control the oxygen content to ≤30 ppm. After the treatment, stop introducing the precursor and the pulsed electric field. Increase the temperature to 150℃ at a rate of 50℃ / h and hold for 4 h. After the holding period, cool with the furnace to room temperature to obtain a high-strength corrosion-resistant aluminum alloy extruded material.

[0054] Example 4

[0055] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0056] Step 1: Place 10 kg of industrial high-purity aluminum ingots with a purity ≥ 99.95% into a medium-frequency induction melting furnace, heat to 740℃ until the aluminum ingots are completely melted, and add the following components in the following proportions: 110 g of high-purity industrial Si (purity ≥ 99.95%), 10 g of high-purity industrial Fe (purity ≥ 99.95%), 20 g of high-purity industrial Cu (purity ≥ 99.95%), 35 g of high-purity industrial Mn (purity ≥ 99.95%), 12 g of high-purity industrial Cr (purity ≥ 99.95%), 5 g of high-purity industrial Zn (purity ≥ 99.95%), and 1 g of high-purity industrial Ti. Add 4g (purity ≥99.95%) of aluminum alloy and stir for 20 minutes until all alloying elements are completely melted. Then add 20g of sodium-free refining agent and use argon gas rotary blowing to refine, degas and remove slag. The argon gas flow rate is controlled at 0.4L / min and the refining time is 20 minutes. After refining, add 130g of high-purity industrial Mg (purity ≥99.95%), stir for 5 minutes until completely melted, and let stand for 15 minutes. Then thoroughly remove the slag from the surface of the melt to obtain pure aluminum melt.

[0057] Step 2: Add 80g of Ti-BC nano-master alloy, 15g of high-purity industrial metal Sc (purity ≥99.95%), 20g of high-purity industrial metal Zr (purity ≥99.95%), 10g of industrial-grade lanthanum-rich mixed rare earth, and 30g of needle-shaped nano-wollastonite to the 10kg aluminum melt prepared above. The Ti:B:C molar ratio in the Ti-BC nano-master alloy is 3:2:1, and the powder particle size is 50-100nm. Immediately afterwards, use a special processing equipment with a closed-loop water-cooled temperature control system to apply high-energy ultrasonic treatment with a power of 1000W and a frequency of 20kHz for 10 minutes. Only the end 15mm of the titanium alloy amplitude transformer is immersed in the melt, and a longitudinal focused pulsed magnetic field with a magnetic induction intensity of 1.2T and a frequency of 15Hz is applied simultaneously for 15 minutes. During the treatment, the melt temperature is stably controlled at 740±3℃ through closed-loop temperature control. After the treatment is completed, keep it at the temperature for 10 minutes and remove the trace amount of slag on the surface of the melt.

[0058] Step 3: Cool the processed melt to 720℃ and prepare ingots using a small semi-continuous casting machine with a graphite lubricated crystallizer. Set the casting speed to 80mm / min, the cooling water pressure to 0.3MPa, and the cooling water flow rate to 1.2m³ / min. 3 The ingots, with dimensions of Φ120mm × 300mm, were air-cooled to room temperature after casting. Then, 30mm of risers at both ends of the ingot were removed using a lathe, and the surface segregation layer was machined to a thickness of 3mm on one side. The treated ingots were then placed in a programmable temperature-controlled box-type heat treatment furnace. The furnace was first heated to 350℃ at a rate of 80℃ / h and held for 7 hours, then heated to 470℃ at a rate of 50℃ / h and held for 10 hours, and finally heated to 555℃ at a rate of 30℃ / h and held for 12 hours. The ingots were removed immediately after the holding period. Forced air cooling to room temperature at a cooling rate of 260℃ / h was applied, followed by sawing of the ingot into 180mm long extrusion blanks. The blanks were then placed in a resistance heating furnace and heated to 490℃ for 2 hours. Simultaneously, the extrusion cylinder was preheated to 440℃ and the extrusion die was preheated to 480℃. Hot extrusion forming was performed using a 2500t horizontal extrusion press with an extrusion ratio of 30:1. The extruded profile was cooled by online water mist at a cooling rate of ≥30℃ / s, resulting in a rectangular extruded profile with a cross-sectional dimension of 30mm×10mm.

[0059] Step 4: Cut the extruded profile prepared above into standard samples with a length of 200 mm, place them in a well-type solution furnace, and perform solution treatment at 550℃ for 30 min. After the heat treatment, immediately transfer the samples to room temperature water for water quenching. The quenching transfer time is ≤8 s, and the water quenching cooling rate is ≥100℃ / s. After quenching, the sample temperature drops to below 45℃. Then, place the samples in a constant temperature box furnace and perform low temperature pre-aging treatment at 115℃. After heat treatment for 7 h, cool them down to 100℃ with the furnace.

[0060] Step 5: Transfer the processed profiles into an atmosphere heat treatment furnace equipped with a strong pulsed electric field generator. Continuously introduce high-purity argon as the carrier gas, with a flow rate controlled at 0.8 L / min. Simultaneously introduce 10 g of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and 30 g of silane-modified nano-SiO2 aerosol. The mass ratio of Yb to Ce in the composite rare earth organic precursor is 2:1. Apply a strong pulsed electric field with a field strength of 10 kV / cm and a frequency of 80 Hz. Hold the material at 110℃ for 12 h. During the treatment, maintain a slight positive pressure 50 Pa higher than the standard atmospheric pressure inside the furnace. Control the oxygen content to ≤30 ppm. After the treatment, stop introducing the precursor and the pulsed electric field. Increase the temperature to 150℃ at a rate of 50℃ / h and hold for 4 h. After the holding period, cool the material to room temperature with the furnace to obtain a high-strength corrosion-resistant aluminum alloy extruded material.

[0061] Example 5

[0062] A method for preparing a high-strength, corrosion-resistant aluminum alloy extrusion material includes the following steps:

[0063] Step 1: Place 10 kg of industrial high-purity aluminum ingots with a purity ≥ 99.95% into a medium-frequency induction melting furnace, heat to 740℃ until the aluminum ingots are completely melted, and add the following components in the following proportions: 110 g of high-purity industrial Si (purity ≥ 99.95%), 10 g of high-purity industrial Fe (purity ≥ 99.95%), 20 g of high-purity industrial Cu (purity ≥ 99.95%), 35 g of high-purity industrial Mn (purity ≥ 99.95%), 12 g of high-purity industrial Cr (purity ≥ 99.95%), 5 g of high-purity industrial Zn (purity ≥ 99.95%), and 1 g of high-purity industrial Ti. Add 4g of high-purity Mg (purity ≥99.95%), heat and stir for 20 minutes until all alloying elements are completely melted. Then add 20g of sodium-free refining agent and use argon gas rotary blowing to refine, degas and remove slag. The argon gas flow rate is controlled at 0.4L / min and the refining time is 20 minutes. After refining, add 130g of high-purity Mg (purity ≥99.95%), heat and stir for 5 minutes until completely melted. After standing for 15 minutes, thoroughly remove the slag on the surface of the melt to obtain pure aluminum melt.

[0064] Step 2: Add 30g of Ti-BC nano-master alloy, 5g of high-purity industrial metal Sc (purity ≥99.95%), 8g of high-purity industrial metal Zr (purity ≥99.95%), 10g of industrial-grade lanthanum-rich mixed rare earth, and 15g of needle-shaped nano-wollastonite to the 10kg aluminum melt prepared above. The Ti:B:C molar ratio in the Ti-BC nano-master alloy is 3:2:1, and the powder particle size is 50-100nm. Immediately afterwards, use a special processing equipment with a closed-loop water-cooled temperature control system to apply high-energy ultrasonic treatment with a power of 1000W and a frequency of 20kHz for 10 minutes. Only the end 15mm of the titanium alloy amplitude transformer is immersed in the melt, and a longitudinal focused pulsed magnetic field with a magnetic induction intensity of 1.2T and a frequency of 15Hz is applied simultaneously for 15 minutes. During the treatment, the melt temperature is stably controlled at 740±3℃ through closed-loop temperature control. After the treatment is completed, keep it at the temperature for 10 minutes and remove the trace amount of slag on the surface of the melt.

[0065] Step 3: Cool the processed melt to 720℃ and prepare ingots using a small semi-continuous casting machine with a graphite lubricated crystallizer. Set the casting speed to 80mm / min, the cooling water pressure to 0.3MPa, and the cooling water flow rate to 1.2m³ / min. 3 The ingots, with dimensions of Φ120mm × 300mm, were air-cooled to room temperature after casting. Then, 30mm of risers at both ends of the ingot were removed using a lathe, and the surface segregation layer was machined to a thickness of 3mm on one side. The treated ingots were then placed in a programmable temperature-controlled box-type heat treatment furnace. The furnace was first heated to 350℃ at a rate of 80℃ / h and held for 7 hours, then heated to 470℃ at a rate of 50℃ / h and held for 10 hours, and finally heated to 555℃ at a rate of 30℃ / h and held for 12 hours. The ingots were removed immediately after the holding period. Forced air cooling to room temperature at a cooling rate of 260℃ / h was applied, followed by sawing of the ingot into 180mm long extrusion blanks. The blanks were then placed in a resistance heating furnace and heated to 490℃ for 2 hours. Simultaneously, the extrusion cylinder was preheated to 440℃ and the extrusion die was preheated to 480℃. Hot extrusion forming was performed using a 2500t horizontal extrusion press with an extrusion ratio of 30:1. The extruded profile was cooled by online water mist at a cooling rate of ≥30℃ / s, resulting in a rectangular extruded profile with a cross-sectional dimension of 30mm×10mm.

[0066] Step 4: Cut the extruded profile prepared above into standard samples with a length of 200 mm, place them in a well-type solution furnace, and perform solution treatment at 540℃ for 20 min. After the heat treatment, immediately transfer the samples to room temperature water for water quenching. The quenching transfer time is ≤8 s, and the water quenching cooling rate is ≥100℃ / s. After quenching, the sample temperature drops to below 45℃. Then, place the samples in a constant temperature box furnace and perform low temperature pre-aging treatment at 115℃. After heat treatment for 7 h, cool them down to 100℃ with the furnace.

[0067] Step 5: Transfer the processed profiles into an atmosphere heat treatment furnace equipped with a strong pulsed electric field generator. Continuously introduce high-purity argon as the carrier gas, with a flow rate controlled at 0.8 L / min. Simultaneously introduce 10 g of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and 15 g of silane-modified nano-SiO2 aerosol. The mass ratio of Yb to Ce in the composite rare earth organic precursor is 2:1. Apply a strong pulsed electric field with a field strength of 10 kV / cm and a frequency of 80 Hz. Hold the material at 110℃ for 12 h. During the treatment, maintain a slight positive pressure 50 Pa higher than the standard atmospheric pressure inside the furnace. Control the oxygen content to ≤30 ppm. After the treatment, stop introducing the precursor and the pulsed electric field. Increase the temperature to 150℃ at a rate of 50℃ / h and hold for 4 h. After the holding period, cool the material to room temperature with the furnace to obtain a high-strength corrosion-resistant aluminum alloy extruded material.

[0068] Comparative Example 1: The difference between Comparative Example 1 and Example 4 is that no nano-intermediate alloy is added in step 2.

[0069] Comparative Example 2: The difference between Comparative Example 2 and Example 4 is that the Yb(acac)3-Ce(acac)3 composite rare earth organic precursor is not introduced in step 5.

[0070] Comparative Example 3: The difference between Comparative Example 3 and Example 4 is that silane-modified nano-SiO2 aerosol is not introduced in step 5.

[0071] Comparative Example 4: The difference between Comparative Example 4 and Example 4 is that lanthanum-rich mixed rare earth and needle-like nano-wollastonite are not added in step 2.

[0072] Comparative Example 5: The difference between Comparative Example 5 and Example 4 is that lanthanum-rich mixed rare earth is not added in step 2.

[0073] Comparative Example 6: The difference between Comparative Example 6 and Example 4 is that needle-shaped nano-wollastonite is not added in step 2.

[0074] Performance testing:

[0075] 1. Mechanical Property Testing: The aluminum alloy extruded profiles prepared in each embodiment and comparative example were processed into standard plate-shaped tensile specimens with a gauge length of 50 mm, a width of 10 mm, and a thickness of 3 mm. Room temperature tensile tests were conducted using a CMT5105 microcomputer-controlled electronic universal testing machine. The test environment temperature was 23 ± 2℃, and the tensile rate was set to 2 mm / min. Each group of specimens was tested in parallel five times. After removing outliers, the average value was taken, and the tensile strength and yield strength of the specimens were recorded. The test results are shown in Table 1.

[0076] 2. Exfoliation Corrosion Performance Test: Test specimens with dimensions of 50mm × 30mm were prepared. The surface oxide scale was removed by sequentially polishing with sandpaper of different grits and ultrasonically cleaning with anhydrous ethanol. The specimens were then completely immersed in a standard EXCO solution (prepared from NaCl, KNO3, and HNO3, with an initial pH of approximately 0.4), maintained at a constant temperature of 25±1℃, and continuously immersed for 48 hours. After immersion, the specimens were removed, rinsed with clean water, and loose corrosion products were removed with a soft brush. After drying, the blistering, delamination, and exfoliation characteristics of the specimen surface were observed visually and under a stereomicroscope. The corrosion morphology was rated according to standard spectra (rating standards from lightest to heaviest: P - pitting corrosion, EA - mild exfoliation, EB - moderate exfoliation, EC - severe exfoliation, ED - extremely severe exfoliation) to determine the alloy's resistance to exfoliation corrosion in a harsh acidic chloride environment. The test results are shown in Table 1.

[0077] 3. Intergranular corrosion performance test: A standard sample (30mm × 10mm × 5mm) that has been cut and polished was immersed in a mixed aqueous solution prepared with sodium chloride (57g / L) and hydrogen peroxide (10mL / L, 30% concentration). The solution was placed in a constant temperature water bath and the test temperature was maintained at 35±2℃ for 6 hours. After immersion, the sample was removed, washed with distilled water and dried with cold air. Then, the sample was cut open along the direction perpendicular to the extrusion direction, and the cross-section was prepared for metallographic analysis. The morphology of the expansion of intergranular corrosion was observed under a high-magnification metallographic microscope. The maximum depth of intergranular corrosion (μm) in 5 consecutive fields of view was measured, and the average value was taken as the intergranular corrosion depth index of the sample. The test results are shown in Table 1.

[0078] 4. Neutral Salt Spray Corrosion Performance Test: Long-term salt spray corrosion resistance was evaluated on the example and comparative samples. The sample dimensions were machined to 50mm × 50mm × thickness. The surface underwent standard pretreatment and the initial mass was accurately weighed (accurate to 0.1mg). The back and sides were sealed with insulating adhesive. The samples were placed in a salt spray test chamber, maintaining the test area temperature at 35±2℃, and continuously sprayed with a neutral salt spray prepared from 5%±0.5% pure NaCl and distilled water, with a pH value controlled between 6.5 and 7.2. The continuous spraying time was set to 500 hours. After the test, the samples were removed and boiled in a boiling water bath in a mixture of chromic acid and phosphoric acid to remove surface corrosion products. After cleaning and drying, the samples were weighed again, and the corrosion weight loss [g / (m]] was calculated. 2 The lower the weight loss rate, the better the overall corrosion resistance of the material and the long-term protective effect of the self-healing passivation film. The test results are shown in Table 1.

[0079] Table 1:

[0080]

[0081] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material, characterized in that, Includes the following steps: (1) Melt high-purity aluminum ingots, add high-purity Si, high-purity Fe, high-purity Cu, high-purity Mn, high-purity Cr, high-purity Zn and high-purity Ti in sequence, keep warm and stir until completely melted, then add sodium-free refining agent for refining, degassing and slag removal, add high-purity Mg after refining, keep warm and stir until completely melted, let stand and remove surface slag to obtain aluminum melt; (2) Add Ti-BC nano-intermediate alloy, high-purity metal Sc, high-purity metal Zr, lanthanum-rich mixed rare earth and needle-shaped nano-wollastonite to the aluminum melt, and then apply high-energy ultrasound and pulsed magnetic field treatment. Control the melt temperature during the treatment process, keep it warm and stand after the treatment is completed, and remove the surface slag. (3) After cooling the melt obtained in step (2), semi-continuous casting is carried out to obtain an ingot. After air cooling, the head and tail risers and surface segregation layer of the ingot are removed. The ingot is subjected to segmented heating and heat preservation heat treatment, forced air cooling, and then sawn into extrusion billets. After heating, hot extrusion is carried out in a preheated extrusion cylinder and extrusion die. The extrusion outlet profile is cooled online to obtain the extrusion profile. (4) The extruded profile is solution treated, kept warm and then water quenched, then pre-aged at low temperature, kept warm and then cooled in the furnace. (5) The profile obtained in step (4) is placed in an atmosphere heat treatment furnace, high-purity argon is introduced, and Yb(acac)3-Ce(acac)3 composite rare earth organic precursor and silane modified nano SiO2 aerosol are introduced. A pulsed electric field is applied, and the material is kept warm. Then, after heating and holding and cooling, a high-strength corrosion-resistant aluminum alloy extruded material is obtained.

2. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (2), the amount of Ti-BC nano-intermediate alloy added is 0.3% to 0.8% of the mass of the aluminum melt.

3. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (2), the molar ratio of Ti:B:C in the Ti-BC nano-intermediate alloy is 3:2:1, and the particle size of the powder is 50-100nm.

4. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (2), the amount of high-purity metal Sc added is 0.05% to 0.15% of the mass of the aluminum melt.

5. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (2), the amount of high-purity metal Zr added is 0.08% to 0.20% of the mass of the aluminum melt.

6. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (2), the mass ratio of lanthanum-rich mixed rare earth to needle-shaped nano-wollastonite is 1:(1.5-3.0).

7. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (4), the solution treatment temperature is 540-550℃ and the solution treatment time is 20-30min.

8. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (5), the mass ratio of Yb(acac)3-Ce(acac)3 composite rare earth organic precursor to silane-modified nano-SiO2 aerosol is 1:(1.5~3.0).

9. The method for preparing a high-strength, corrosion-resistant aluminum alloy extruded material according to claim 1, characterized in that, In step (5), the mass ratio of Yb to Ce in the Yb(acac)3-Ce(acac)3 composite rare earth organic precursor is 2:

1.

10. A high-strength, corrosion-resistant aluminum alloy extrusion material, characterized in that, It is prepared by the method described in any one of claims 1 to 9 above.

Images