Regulation and control process for precipitated phase distribution of regenerated 6XXX series aluminum alloy based on electromagnetic-ultrasonic composite field

Abstract

The invention discloses a process for regulating and controlling precipitated phase distribution of regenerated 6XXX series aluminum alloy based on an electromagnetic-ultrasonic composite field, and relates to the technical field of metal material processing. The method comprises the following steps: introducing a carboxyl modified polyaryletherketone-siloxane copolymer assistant in a solid-phase temperature zone, applying ultrasonic waves to synchronously act with a pulsed magnetic field, and then carrying out artificial aging. According to the method, the aging peak time is remarkably shortened, the precipitated phase is refined and homogenized, the mechanical property is obviously improved, and an innovative and efficient path is provided for improving the structure stability and performance consistency of the regenerated aluminum alloy.

Description

Technical Field

[0001] This invention relates to the field of metal material processing technology, and in particular to a process for controlling the distribution of precipitated phases in regenerated 6XXX series aluminum alloys based on an electromagnetic-ultrasonic composite field. Background Technology

[0002] 6XXX series (Al-Mg-Si series) aluminum alloys are widely used in the automotive, aerospace, and construction industries due to their excellent mechanical properties, good plasticity, suitable age-hardening potential, and good corrosion resistance. Their strengthening primarily depends on the morphology, size, and distribution of precipitated phases (such as β″ and β′) within the matrix. Traditional strengthening routes mainly include casting, solution treatment, quenching, and artificial aging. Although the technology is relatively mature,

[0003] However, problems such as uneven distribution of precipitated phases, coarse grains, and fluctuations in mechanical properties still exist.

[0004] Although patent documents such as US8999079B2 propose improving the properties of 6XXX series aluminum alloys and shortening the aging time through post-solution cold work, thereby increasing the strength by 5–25% and the elongation by 6–15%, this method still mainly focuses on the coupling path of heat treatment and cold work, without involving the microscopic control of the morphology of precipitated phases through novel external fields or additives.

[0005] Ultrasonic treatment: As described in Japanese Patent JP2007-216239A1, applying ultrasound at or above the melt liquidus line can refine the solidification structure and suppress the formation of coarse eutectic phases. Although this technology is specific to high-Si aluminum alloys, it proves the feasibility of ultrasound in refining the microstructure of aluminum alloys.

[0006] The improvement of metal properties by ultrasound: WO2007 / 038378A2 proposed that ultrasound can improve the service performance of metals and enhance their ability to inhibit thermal or environmentally induced degradation. It reveals that ultrasound can not only inherit plastic structures, but also improve the fatigue and corrosion resistance of alloys.

[0007] Although no published patents were found that explicitly couple electromagnetic fields with the distribution of precipitates in aluminum alloys, literature reviews (such as studies on the influence of external fields on mineral precipitation) indicate that electromagnetic fields can regulate precipitation initiation and kinetics, providing a theoretical basis for the regulation of precipitates in aluminum alloys.

[0008] Currently, no systematic technical solution has been found in the market or literature for the refined control of precipitated phases by using electromagnetic-ultrasonic composite field coupling treatment combined with organic-inorganic additives for the treatment of recycled 6XXX series aluminum alloys. Summary of the Invention

[0009] Based on the aforementioned technological status, this invention proposes a process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys using an electromagnetic-ultrasonic composite field. During the manufacturing process of recycled 6XXX series aluminum alloys, a "carboxyl-modified polyaryletherketone-siloxane copolymer" additive is synthesized and loaded onto a high-temperature resistant carrier. Introduced before solution quenching of the alloy, the "electromagnetic-ultrasonic composite field" works synergistically to refine the size and uniformize the distribution of precipitates, thereby improving mechanical properties and solving the unique microstructure inhomogeneity problem of recycled materials.

[0010] The technical solution is as follows:

[0011] A process for controlling the distribution of precipitated phases in regenerated 6XXX series aluminum alloys based on an electromagnetic-ultrasonic composite field includes the following steps:

[0012] a) Melt and purify 1000 parts of recycled 6XXX series aluminum alloy by weight;

[0013] b) When the purified aluminum alloy is in the solid-phase low-temperature stage of 100-200℃, the supported additive is introduced into the aluminum alloy, and an electromagnetic-ultrasonic composite field is applied at the same time.

[0014] c) Solution treatment, rapid cooling and aging treatment.

[0015] Furthermore, the melting temperature of the aluminum alloy in step a) is 700-750℃.

[0016] Further, in step a), the purification is carried out by rotary jetting of inert gas: gas: Ar; flow rate 10-20 L / min; rotor speed 300-600 rpm; processing time 10-30 min.

[0017] Further, the preparation method of the supported auxiliary agent in step b) is as follows:

[0018] By mass, 60-80 parts of silicon carbide whiskers are dispersed in 500-700 parts of toluene, and 3-5 parts of vinyltriethoxysilane are added. The mixture is reacted at 60-70°C for 60-90 minutes to obtain a surface vinyl-modified silicon carbide support.

[0019] A surface vinyl-modified silicon carbide carrier was mixed with a carboxyl-modified polyaryletherketone-siloxane copolymer additive at a mass ratio of 8:1 and reacted at 80-100℃ for 3 hours to allow the additive to be loaded onto the carrier surface through double bond addition. After drying, the supported additive was obtained.

[0020] Furthermore, the preparation method of the carboxyl-modified polyaryletherketone-siloxane copolymer additive is as follows:

[0021] According to the mass fraction, 40-60 parts of hydrogen-containing polyarylether ketone, 30-50 parts of p-carboxystyrene, and 1-3 parts of 2,1,3-benzothiazol-4-yl isocyanate are added to 90-130 parts of diphenyl sulfone and stirred and dispersed under nitrogen protection; 2-4 parts of platinum-carbon catalyst are added and reacted at 180-200℃ for 5-8 hours to obtain carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0022] Further, in step b), the supported additive is introduced into the aluminum alloy:

[0023] The supported additives are dispersed in solvents such as anhydrous isopropanol or ethanol, with a solid content of 5-15 wt%; a 5-20 μm wet film is formed by spraying, dipping or roller coating; and dried at 150-200℃ for 10-20 min.

[0024] Furthermore, the electromagnetic-ultrasonic combined field parameters in step b) are:

[0025] Ultrasonic field: fitted with ultrasonic transducer or acoustic clamp, frequency 20-40kHz, power density 5-15W / cm² 2 Duty cycle 50-100%, processing time 10-30 min.

[0026] Furthermore, the electromagnetic-ultrasonic combined field parameters in step b) are:

[0027] Electromagnetic field: Pulsed magnetic field mode, magnetic induction intensity 0.2-1.0T, pulse frequency 1-50Hz, duty cycle 10-50%, processing time 10-30min.

[0028] Furthermore, in step c), the solution treatment temperature is 515-545℃, and the holding time is 0.5-2h; the rapid cooling method is water quenching at ≤60℃, and the cooling time is ≤5-10s.

[0029] Furthermore, the manual aging process in step c) is as follows:

[0030] Single-stage: 4-10 hours at 160-180℃ or 1-3 hours at 200℃;

[0031] Or two-stage: 2-4 hours at 160℃ or 2-4 hours at 180-190℃.

[0032] Reaction mechanism

[0033] Synthesis mechanism of the auxiliary agent: The Si-H bond of the hydrogen-containing polyarylether ketone undergoes a hydrosilylation reaction with the carbon-carbon double bond of p-carboxystyrene under platinum catalysis, introducing a carboxyl group; the isocyanate group of 2,1,3-benzothiazolium tetraisocyanate reacts with the carboxyl group to introduce a thiazole ring, which enhances the π-π stacking effect between the auxiliary agent and the precipitated phase.

[0034] Loading mechanism: The vinyl groups on the surface of silicon carbide whiskers undergo an addition reaction with the double bonds in the additives, ensuring stable loading of the additives at high temperatures; the high strength of silicon carbide prevents the carrier from breaking under the influence of the composite field.

[0035] Precipitation phase regulation mechanism: The carboxyl groups in the additive adsorb onto the surface of the precipitated phase, changing its surface energy; the thiazole ring forms an oriented interaction with the precipitated phase, and under the force field driven by the electromagnetic and ultrasonic composite field, it guides the precipitated phase to oriented arrangement, reducing distribution deviation.

[0036] Technical effects:

[0037] 1. Refinement and homogenization of precipitated phase

[0038] The additives form microscopic heterogeneous nucleation sites in the solid phase, which, together with the acoustic-magnetic composite field, activate grain boundaries and dislocations, significantly promoting the uniform precipitation of β″ and β′ type precipitates. Compared with traditional strengthening methods relying solely on heat treatment, this method can achieve a reduction in precipitate size, an increase in quantity, and a more uniform distribution.

[0039] 2. Time-sensitivity dynamics optimization: peak time shortened

[0040] Electromagnetic / ultrasonic fields promote internal strain and diffusion, significantly shortening the time required for artificial aging to reach peak hardness. Combined with nucleation sites provided by additives, this makes the strengthening process more efficient and energy-saving, especially suitable for industrial-scale implementation.

[0041] 3. Suppressing the effects of macroscopic tissue segregation and inclusions

[0042] Although its main function is in the solid phase, the composite field-binding agent can also buffer the unevenness of the microstructure after quenching, indirectly improving the macroscopic segregation problem caused by recycled material origin. Similar electromagnetic-assisted solidification technology has been proven to reduce "dendritic spacing" and macroscopic segregation zones. Detailed Implementation

[0043] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0044] Example 1

[0045] a) Aluminum alloy melting and purification

[0046] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 700℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 10 L / min, the rotor speed to 300 rpm, and continue to process for 10 min to remove the gas and inclusions in the melt.

[0047] b) Introduction of supported additives and compound field treatment

[0048] Preparation of supported additives:

[0049] 60 kg of silicon carbide whiskers were dispersed in 500 kg of toluene, stirred evenly, and then 3 kg of vinyltriethoxysilane was added. The mixture was heated to 60 °C and reacted for 60 minutes to obtain a surface vinyl-modified silicon carbide support.

[0050] Preparation of additives: 40 kg of hydrogen-containing polyarylether ketone, 30 kg of p-carboxystyrene, and 1 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 90 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 2 kg of platinum-carbon catalyst was added, and the mixture was heated to 180 °C and reacted for 5 hours to obtain the carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0051] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 80°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 80°C for 6 hours to obtain the supported additive.

[0052] Introduction of adjuvants:

[0053] The supported additive was dispersed in anhydrous isopropanol, and the solid content was controlled at 5wt%. A 5μm wet film was formed on the cleaned aluminum alloy surface by spraying. The film was then dried in a 150℃ forced-air drying oven for 10 minutes.

[0054] Electromagnetic-ultrasonic composite field treatment:

[0055] When the aluminum alloy is in the solid-state low-temperature stage (100°C), a composite field is simultaneously applied:

[0056] Ultrasonic field: fitted to the ultrasonic transducer, frequency set at 20kHz, power density at 5W / cm². 2 Duty cycle 50%, processing time 10 minutes;

[0057] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.2T, pulse frequency at 1Hz, duty cycle at 10%, and processing time at 10min.

[0058] c) Solution treatment, rapid cooling and aging treatment

[0059] Solution treatment: Heat the aluminum alloy to 515℃ and hold for 0.5 hours;

[0060] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤5s;

[0061] Artificial aging (single-stage): Place the cooled aluminum alloy in a 160℃ oven and keep it at that temperature for 4 hours.

[0062] Example 2

[0063] a) Aluminum alloy melting and purification

[0064] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 720℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 14 L / min, the rotor speed to 400 rpm, and continue to process for 18 min to remove the gas and inclusions in the melt.

[0065] b) Introduction of supported additives and compound field treatment

[0066] Preparation of supported additives:

[0067] 68 kg of silicon carbide whiskers were dispersed in 580 kg of toluene, stirred evenly, and then 4 kg of vinyltriethoxysilane was added. The mixture was heated to 65 °C and reacted for 70 minutes to obtain a surface vinyl-modified silicon carbide support.

[0068] Preparation of additives: 48 kg of hydrogen-containing polyarylether ketone, 38 kg of p-carboxystyrene, and 2 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 105 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 3 kg of platinum-carbon catalyst was added, and the mixture was heated to 190 °C and reacted for 6 hours to obtain the carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0069] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 90°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 85°C for 5 hours to obtain the supported additive.

[0070] Introduction of adjuvants:

[0071] The supported additives were dispersed in ethanol, and the solid content was controlled at 9 wt%. A 10 μm wet film was formed on the surface of the purified aluminum alloy by impregnation. The film was then dried in a 170℃ forced-air drying oven for 14 min.

[0072] Electromagnetic-ultrasonic composite field treatment:

[0073] When the aluminum alloy is in the solid-state low-temperature stage (130℃), a composite field is simultaneously applied:

[0074] Ultrasonic field: Using acoustic clamps, set the frequency to 28kHz and the power density to 8W / cm². 2 Duty cycle 70%, processing time 18 minutes;

[0075] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.5T, pulse frequency at 15Hz, duty cycle at 25%, and processing time at 18min.

[0076] c) Solution treatment, rapid cooling and aging treatment

[0077] Solution treatment: Heat the aluminum alloy to 525℃ and hold for 1 hour;

[0078] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤7s;

[0079] Artificial aging (single-stage): The cooled aluminum alloy is placed in an oven at 170℃ and kept at that temperature for 7 hours.

[0080] Example 3

[0081] a) Aluminum alloy melting and purification

[0082] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 740℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 18 L / min, the rotor speed to 500 rpm, and continue to process for 25 min to remove the gas and inclusions in the melt.

[0083] b) Introduction of supported additives and compound field treatment

[0084] Preparation of supported additives:

[0085] 75 kg of silicon carbide whiskers were dispersed in 650 kg of toluene, stirred evenly, and then 4.5 kg of vinyltriethoxysilane was added. The mixture was heated to 68 °C and reacted for 85 minutes to obtain a surface vinyl-modified silicon carbide support.

[0086] Preparation of additives: 55 kg of hydrogen-containing polyarylether ketone, 45 kg of p-carboxystyrene, and 2.5 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 120 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 3.5 kg of platinum-carbon catalyst was added, and the mixture was heated to 195 °C and reacted for 7 hours to obtain the carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0087] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 95°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 90°C for 5 hours to obtain the supported additive.

[0088] Introduction of adjuvants:

[0089] The supported additives were dispersed in anhydrous isopropanol, and the solid content was controlled at 13 wt%. A 16 μm wet film was formed on the cleaned aluminum alloy surface by roller coating. The film was then dried in a 190℃ forced-air drying oven for 18 min.

[0090] Electromagnetic-ultrasonic composite field treatment:

[0091] When the aluminum alloy is in the solid-state low-temperature stage of 170°C, a composite field is simultaneously applied:

[0092] Ultrasonic field: fitted with an ultrasonic transducer, set at a frequency of 35kHz and a power density of 12W / cm². 2 Duty cycle 90%, processing time 25 minutes;

[0093] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.8T, pulse frequency at 35Hz, duty cycle at 40%, and processing time at 25min.

[0094] c) Solution treatment, rapid cooling and aging treatment

[0095] Solution treatment: Heat the aluminum alloy to 535℃ and hold for 1.5 hours;

[0096] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤9s;

[0097] Artificial aging (two-stage): First, place the cooled aluminum alloy in a 160℃ oven for 3 hours, then raise the temperature to 185℃ and hold for 3 hours.

[0098] Example 4

[0099] a) Aluminum alloy melting and purification

[0100] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 750℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 20 L / min, the rotor speed to 600 rpm, and continue to process for 30 min to remove the gas and inclusions in the melt.

[0101] b) Introduction of supported additives and compound field treatment

[0102] Preparation of supported additives:

[0103] 80 kg of silicon carbide whiskers were dispersed in 700 kg of toluene, stirred evenly, and then 5 kg of vinyltriethoxysilane was added. The mixture was heated to 70 °C and reacted for 90 minutes to obtain a surface vinyl-modified silicon carbide support.

[0104] Preparation of additives: 60 kg of hydrogen-containing polyarylether ketone, 50 kg of p-carboxystyrene, and 3 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 130 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 4 kg of platinum-carbon catalyst was added, and the mixture was heated to 200 °C and reacted for 8 hours to obtain the carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0105] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 100°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 95°C for 4 hours to obtain the supported additive.

[0106] Introduction of adjuvants:

[0107] The supported additives were dispersed in ethanol, and the solid content was controlled at 15 wt%. A 20 μm wet film was formed on the surface of the purified aluminum alloy by spraying. The film was then dried in a 200℃ forced-air drying oven for 20 min.

[0108] Electromagnetic-ultrasonic composite field treatment:

[0109] When the aluminum alloy is in the solid-state low-temperature stage (200℃), a composite field is simultaneously applied:

[0110] Ultrasonic field: Using acoustic clamps, set the frequency to 40kHz and the power density to 15W / cm². 2 Duty cycle 100%, processing time 30 minutes;

[0111] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 1.0T, pulse frequency at 50Hz, duty cycle at 50%, and processing time at 30min.

[0112] c) Solution treatment, rapid cooling and aging treatment

[0113] Solution treatment: Heat the aluminum alloy to 545℃ and hold for 2 hours;

[0114] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤10s;

[0115] Artificial aging (two-stage): First, place the cooled aluminum alloy in a 160℃ oven for 4 hours, then raise the temperature to 190℃ and hold for 4 hours.

[0116] Comparative Example 1

[0117] a) Aluminum alloy melting and purification

[0118] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 700℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 10 L / min, the rotor speed to 300 rpm, and continue to process for 10 min to remove the gas and inclusions in the melt.

[0119] b) Complex Field Treatment

[0120] Electromagnetic-ultrasonic composite field treatment:

[0121] When the aluminum alloy is in the solid-state low-temperature stage (100°C), a composite field is simultaneously applied:

[0122] Ultrasonic field: fitted to the ultrasonic transducer, frequency set at 20kHz, power density at 5W / cm². 2 Duty cycle 50%, processing time 10 minutes;

[0123] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.2T, pulse frequency at 1Hz, duty cycle at 10%, and processing time at 10min.

[0124] c) Solution treatment, rapid cooling and aging treatment

[0125] Solution treatment: Heat the aluminum alloy to 515℃ and hold for 0.5 hours;

[0126] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤5s;

[0127] Artificial aging (single-stage): Place the cooled aluminum alloy in a 160℃ oven and keep it at that temperature for 4 hours.

[0128] Comparative Example 2

[0129] a) Aluminum alloy melting and purification

[0130] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 700℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 10 L / min, the rotor speed to 300 rpm, and continue to process for 10 min to remove the gas and inclusions in the melt.

[0131] b) Introduction of supported additives and compound field treatment

[0132] Preparation of supported additives:

[0133] 60 kg of silicon carbide whiskers were dispersed in 500 kg of toluene, stirred evenly, and then 3 kg of vinyltriethoxysilane was added. The mixture was heated to 60 °C and reacted for 60 minutes to obtain a surface vinyl-modified silicon carbide support.

[0134] Preparation of additives: 30 kg of p-carboxystyrene and 1 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 90 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 2 kg of platinum-carbon catalyst was added, and the temperature was raised to 180 °C and reacted for 5 hours to obtain the carboxylated modified polyaryletherketone-siloxane copolymer additive.

[0135] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 80°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 80°C for 6 hours to obtain the supported additive.

[0136] Introduction of adjuvants:

[0137] The supported additive was dispersed in anhydrous isopropanol, and the solid content was controlled at 5wt%. A 5μm wet film was formed on the cleaned aluminum alloy surface by spraying. The film was then dried in a 150℃ forced-air drying oven for 10 minutes.

[0138] Electromagnetic-ultrasonic composite field treatment:

[0139] When the aluminum alloy is in the solid-state low-temperature stage (100°C), a composite field is simultaneously applied:

[0140] Ultrasonic field: fitted to the ultrasonic transducer, frequency set at 20kHz, power density at 5W / cm². 2 Duty cycle 50%, processing time 10 minutes;

[0141] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.2T, pulse frequency at 1Hz, duty cycle at 10%, and processing time at 10min.

[0142] c) Solution treatment, rapid cooling and aging treatment

[0143] Solution treatment: Heat the aluminum alloy to 515℃ and hold for 0.5 hours;

[0144] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤5s;

[0145] Artificial aging (single-stage): Place the cooled aluminum alloy in a 160℃ oven and keep it at that temperature for 4 hours.

[0146] Comparative Example 3

[0147] a) Aluminum alloy melting and purification

[0148] Take 1000 kg of recycled 6XXX series aluminum alloy, add it to the melting furnace, and heat it to 700℃ to completely melt it; use the rotary jet inert gas method for purification: introduce Ar gas, control the gas flow rate to 10 L / min, the rotor speed to 300 rpm, and continue to process for 10 min to remove the gas and inclusions in the melt.

[0149] b) Introduction of supported additives and compound field treatment

[0150] Preparation of supported additives:

[0151] 60 kg of silicon carbide whiskers were dispersed in 500 kg of toluene, stirred evenly, and then 3 kg of vinyltriethoxysilane was added. The mixture was heated to 60 °C and reacted for 60 minutes to obtain a surface vinyl-modified silicon carbide support.

[0152] Preparation of additives: 40 kg of hydrogen-containing polyarylether ketone and 1 kg of 2,1,3-benzothiazol-4-yl isocyanate were added to 90 kg of diphenyl sulfone, and nitrogen gas was introduced for protection. The mixture was stirred and dispersed evenly. 2 kg of platinum-carbon catalyst was added, and the temperature was raised to 180℃ and reacted for 5 hours to obtain the carboxyl-modified polyarylether ketone-siloxane copolymer additive.

[0153] The above-mentioned surface vinyl-modified silicon carbide carrier and the additive were mixed at a mass ratio of 8:1, heated to 80°C and reacted for 3 hours, so that the additive was loaded onto the carrier surface through double bond addition. The carrier was then dried under vacuum at 80°C for 6 hours to obtain the supported additive.

[0154] Introduction of adjuvants:

[0155] The supported additive was dispersed in anhydrous isopropanol, and the solid content was controlled at 5wt%. A 5μm wet film was formed on the cleaned aluminum alloy surface by spraying. The film was then dried in a 150℃ forced-air drying oven for 10 minutes.

[0156] Electromagnetic-ultrasonic composite field treatment:

[0157] When the aluminum alloy is in the solid-state low-temperature stage (100°C), a composite field is simultaneously applied:

[0158] Ultrasonic field: fitted to the ultrasonic transducer, frequency set at 20kHz, power density at 5W / cm². 2 Duty cycle 50%, processing time 10 minutes;

[0159] Electromagnetic field: Pulsed magnetic field method is adopted, with magnetic induction intensity set at 0.2T, pulse frequency at 1Hz, duty cycle at 10%, and processing time at 10min.

[0160] c) Solution treatment, rapid cooling and aging treatment

[0161] Solution treatment: Heat the aluminum alloy to 515℃ and hold for 0.5 hours;

[0162] Rapid cooling: Immediately immerse in water at ≤60℃ for water quenching, and control the cooling time to ≤5s;

[0163] Artificial aging (single-stage): Place the cooled aluminum alloy in a 160℃ oven and keep it at that temperature for 4 hours.

[0164] Test method:

[0165] 1. Tensile test (room temperature)

[0166] Standard: kgB / T228.1-2021 (Room temperature method).

[0167] Sample: The sheet material is a standard dumbbell shape in the L direction, with a parallel section width of 12.5 mm; the extensometer gauge length is 50 mm.

[0168] Indicators: Yield strength (Rp0.2), tensile strength (UTS), elongation after fracture (A50).

[0169] 2. Microhardness (HV10)

[0170] Standard: kgB / T4340.1-2024 (Vickers Hardness Test Method).

[0171] Conditions: The cross-section of the sample was polished with 1μm colloidal silica; the load was 98.07N (HV10) and held for 12–15s; each sample had n≥10 points, and the mean ± standard deviation was reported after removing outliers.

[0172] 3. Differential Scanning Calorimetry (DSC)

[0173] Objective: To obtain the characteristic peaks of the exothermic precipitation (β″ / β′) and their position shifts for comparison of aging kinetic changes.

[0174] Conditions: Purified argon gas protection; heating rate 10K / min; test temperature range 30–450℃; comparison of peak temperature and peak area.

[0175] Test results:

[0176] Table 1. Results of Mechanical Properties and Hardness Tests

[0177] Rp0.2 / MPa UTS / MPa A50 / ％ HV10 Example 1 262 305 11.4 98 Example 2 269 318 11.8 100 Example 3 275 326 12.1 102 Example 4 281 337 12.4 103 Comparative Example 1 242 288 10.2 92 Comparative Example 2 251 295 10.7 94 Comparative Example 3 255 299 11.0 95

[0178] Table 2 Results of aging kinetics test

[0179]

[0180]

[0181] As can be seen from the test results of the above embodiments and comparative examples, the aging kinetics optimization of this method is optimized, the mechanical properties are significantly enhanced, and the influence of macroscopic segregation and inclusions is effectively suppressed.

[0182] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A process for the control of the distribution of precipitates in recycled 6XXX series aluminium alloys based on the electromagnetic-ultrasonic complex field, characterized by, The method comprises the following steps: a) melting and purifying 1000 parts of recycled 6XXX series aluminum alloy by mass fraction; b) introducing the supported additive into the aluminum alloy when the purified aluminum alloy is in the solid phase low temperature stage of 100-200℃, while applying electromagnetic-ultrasonic composite field; c) solid solution treatment, rapid cooling and aging treatment; The supported additive is prepared by reaction of silicon carbide whisker, vinyltriethoxysilane and carboxyl-modified polyaryletherketone-siloxane copolymer additive; The carboxyl-modified polyaryletherketone-siloxane copolymer additive is prepared by reaction of hydrogen-containing polyaryletherketone, p-carboxystyrene, 2,1,3-benzothiazole-4-yl isocyanate and platinum-carbon catalyst.

2. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The aluminum alloy melting temperature in step a) is 700-750℃.

3. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The purification in step a) is rotary blowing of inert gas: gas: Ar; flow rate 10-20 L / min; rotor speed 300-600 rpm; treatment time 10-30 min.

4. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The preparation method of the supported additive in step b) is as follows: 60-80 parts of silicon carbide whisker by mass fraction is dispersed in 500-700 parts of toluene by mass fraction, 3-5 parts of vinyltriethoxysilane is added, and reaction is carried out at 60-70℃ for 60-90 min to obtain silicon carbide carrier with surface vinyl modification; The silicon carbide carrier with surface vinyl modification is mixed with the carboxyl-modified polyaryletherketone-siloxane copolymer additive at a mass ratio of 8:1, and reaction is carried out at 80-100℃ for 3 h to load the additive on the surface of the carrier by double bond addition, and the supported additive is obtained after drying.

5. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the combined electromagnetic-ultrasonic field according to claim 4, characterized in that: The preparation method of the carboxyl-modified polyaryletherketone-siloxane copolymer additive is as follows: 40-60 parts of hydrogen-containing polyaryletherketone, 30-50 parts of p-carboxystyrene and 1-3 parts of 2,1,3-benzothiazole-4-yl isocyanate are added into 90-130 parts of diphenyl sulfone, and stirring and dispersion are carried out under nitrogen protection; 2-4 parts of platinum-carbon catalyst is added, and reaction is carried out at 180-200℃ for 5-8 h to obtain the carboxyl-modified polyaryletherketone-siloxane copolymer additive.

6. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The step of introducing the supported additive into the aluminum alloy in step b) is as follows: The supported additive is dispersed in anhydrous isopropyl alcohol or ethanol solvent, and the solid content is 5-15 wt%; a wet film with a thickness of 5-20 μm is formed by spraying, dipping or rolling; and drying is carried out at 150-200℃ for 10-20 min.

7. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The electromagnetic-ultrasonic composite field parameters in step b) are as follows: Ultrasound field: fitted with an ultrasound transducer or sonotrode, frequency 20-40 kHz, power density 5-15 W / cm 2 , duty cycle 50-100%, treatment time 10-30 min.

8. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The electromagnetic-ultrasonic composite field parameters in step b) are as follows: Electromagnetic field: pulsed magnetic field mode, magnetic induction intensity 0.2-1.0 T, pulse frequency 1-50 Hz, duty cycle 10-50%, treatment time 10-30 min.

9. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The solid solution treatment temperature in step c) is 515-545℃, and the holding time is 0.5-2 h; The rapid cooling method is water quenching at ≤60℃, and the cooling time is ≤5-10 s.

10. The process for controlling the distribution of precipitates in recycled 6XXX series aluminum alloys based on the electromagnetic-ultrasonic complex field according to claim 1, characterized by the fact that: The artificial aging in step c) is as follows: single stage: 4-10 h at 160-180℃ or 1-3 h at 200℃; or double stage: 2-4 h at 160℃ + 2-4 h at 180-190℃.

Images