High-power tooth radiator aluminum alloy strengthening and toughening heat treatment method

Abstract

The invention relates to the technical field of aluminum alloy heat treatment, and discloses a high-power tooth radiator aluminum alloy strengthening and toughening heat treatment method. Gradient temperature control solution treatment including at least two different temperature stages; step 2; carrying out electromagnetic auxiliary shape correction treatment, and applying an alternating magnetic field in the cooling process; step 3; the two-stage aging treatment comprises high-temperature first-stage aging and low-temperature second-stage aging; step 4; carrying out pulse type aging strengthening by adopting a periodic temperature fluctuation mode; step 5; and performing micro-arc oxidation surface treatment to generate an aluminum oxide layer in the electrolyte. Gradient temperature control solution treatment is adopted, a beta phase is fully dissolved, abnormal growth of crystal grains is inhibited, meanwhile, uniform nucleation of a GP region and dispersed distribution of a theta'phase are promoted through two-stage aging treatment, the strength and toughness of the alloy are improved, in addition, electromagnetic auxiliary shape correction and a composite residual stress elimination technology are combined, thermal stress deformation is effectively inhibited, residual stress is eliminated, and the performance of the alloy is improved. The size stability and the fatigue life are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy heat treatment, and particularly to a method for strengthening and toughening heat treatment of aluminum alloy for high-finned heat sinks. Background Art

[0002] Aluminum alloy for high-finned heat sinks is a high-performance material widely used in the field of electronic heat dissipation. It has characteristics such as high thermal conductivity, good mechanical properties, and excellent dimensional accuracy. This kind of aluminum alloy is usually used to manufacture high-density and high-precision heat sinks, which can effectively improve the heat dissipation efficiency and meet the high requirements of modern electronic devices for heat dissipation performance. In the processing of aluminum alloy for high-finned heat sinks, in order to further improve its mechanical properties and service life, strengthening and toughening heat treatment is an essential process. The main role of strengthening and toughening heat treatment is to optimize the microstructure of the alloy and improve its strength and toughness. Specifically, heat treatment can promote the precipitation of strengthening phases in the alloy and at the same time improve the tissue uniformity of the alloy, thereby enhancing the mechanical properties such as the tensile strength, yield strength, and elongation of the material;

[0003] However, in the prior art, when strengthening and toughening heat treatment is carried out on aluminum alloy for high-finned heat sinks, a single solution treatment temperature is often used. The single solution treatment temperature cannot fully meet the dissolution and precipitation requirements of different phases in the alloy, resulting in incomplete precipitation of some strengthening phases. This single temperature setting leads to an incomplete recrystallization process, thereby affecting the final performance of the alloy.

[0004] To solve the above problems, a method for strengthening and toughening heat treatment of aluminum alloy for high-finned heat sinks is proposed in this application. Summary of the Invention

[0005] The present invention proposes a method for strengthening and toughening heat treatment of aluminum alloy for high-finned heat sinks, which solves the problem that the use of a single solution treatment temperature in the related art cannot fully meet the dissolution and precipitation requirements of different phases in the alloy.

[0006] The method for strengthening and toughening heat treatment of aluminum alloy for high-finned heat sinks proposed by the present invention includes the following steps:

[0007] Step 1: Gradient temperature-controlled solution treatment, including at least two different temperature stages;

[0008] Step 2: Electromagnetic-assisted shape correction treatment, applying an alternating magnetic field during the cooling process;

[0009] Step 3: Two-stage aging treatment, including high-temperature primary aging and low-temperature secondary aging;

[0010] Step 4: Pulse aging strengthening, adopting a periodic temperature fluctuation mode;

[0011] Step Five: Micro-arc oxidation surface treatment to generate an alumina layer in the electrolyte;

[0012] Step Six: Anisotropy regulation treatment by applying a directional pre-strain;

[0013] Step Seven: Composite residual stress elimination by combining cryogenic treatment and ultrasonic vibration treatment;

[0014] Step Eight: Intelligent process parameter optimization by dynamically adjusting the processing parameters based on machine learning algorithms.

[0015] As a further optimized solution of the present invention, the gradient temperature-controlled solution treatment in Step One specifically includes:

[0016] High-temperature phase dissolution stage: The aluminum alloy workpiece is heated to 520 - 540°C at a rate of 8 - 12°C / min, and held for 20 - 40 minutes in a nitrogen-protected atmosphere to completely dissolve the β phase;

[0017] Intermediate-temperature grain boundary regulation stage: Cool down to 470 - 490°C at a rate of ≤5°C / min, switch to an argon atmosphere and hold for 30 - 60 minutes to inhibit abnormal grain growth;

[0018] Gradient cooling stage: Adopt a segmented cooling mode, first rapidly cool to 300°C at a rate of 15 - 20°C / min, and then slowly cool to room temperature at a rate of ≤3°C / min to control the gradient distribution of vacancy concentration.

[0019] As a further optimized solution of the present invention, the electromagnetic-assisted shape correction treatment in Step Two specifically includes:

[0020] Magnetic field parameter setting: When the workpiece temperature drops to 250 - 300°C, apply a 0.3 - 0.8T transverse alternating magnetic field with a frequency of 10 - 30 kHz, and the magnetic field direction forms an angle of 45 - 90° with the arrangement direction of the heat dissipation teeth;

[0021] Dynamic field strength adjustment: According to the infrared temperature measurement feedback, reduce the magnetic field strength at a ratio of ΔB = 0.1T / 50°C until the workpiece temperature ≤150°C;

[0022] Directional cooling control: Combine with the magnetic field application direction, adopt an asymmetric air-cooling system, and the cooling rate in the tooth tip area is 20 - 30% faster than that in the tooth root area to inhibit thermal stress deformation.

[0023] As a further optimized solution of the present invention, the two-stage aging treatment in Step Three specifically includes:

[0024] First-stage GP zone formation: Age at 180 - 200°C for 1.5 - 2.5 hours, introduce 5 - 10 vol.% nitrogen for protection to promote the uniform nucleation of solute atom clusters in the GP zone;

[0025] Transition stage pressure control: During the natural cooling process to 150 - 170 °C, apply a hydrostatic pressure of 0.1 - 0.5 MPa to the workpiece to eliminate microvoids;

[0026] Secondary θ' phase precipitation: Maintain the temperature at 150 - 170 °C in the aging furnace for 4 - 6 hours. Turn on the ultrasonic vibration at 28 kHz and an amplitude of 10 μm every 1 hour to promote the dispersion distribution of the θ' phase, Al2Cu.

[0027] As a further optimized solution of the present invention, the pulsed aging strengthening in step four specifically includes:

[0028] Temperature fluctuation programming: Set the aging temperature to fluctuate within the range of the target value ±8 - 12 °C, with a single - cycle duration of 10 - 20 minutes and a total number of cycles of 10 - 30 times;

[0029] Dynamic compensation control: Automatically adjust the temperature fluctuation amplitude according to the on - line monitoring results of resistivity;

[0030] Gradient termination mechanism: In the last 3 cycle periods, linearly reduce the temperature fluctuation amplitude to ±2 °C to reduce the sudden change of interface energy.

[0031] As a further optimized solution of the present invention, the micro - arc oxidation surface treatment in step five specifically includes:

[0032] Electrolyte preparation: Use an aqueous electrolyte containing 10 - 20 g / L of sodium silicate, 5 - 15 g / L of sodium dihydrogen phosphate, and 1 - 5 g / L of potassium hydroxide, and maintain the pH value at 11 - 13;

[0033] Pulsed discharge treatment: Apply a bipolar pulsed voltage of 400 - 500 V, with a positive pulse width of 100 - 200 μs, a negative pulse width of 50 - 100 μs, and a frequency of 500 - 1000 Hz;

[0034] In - situ sealing and strengthening: After oxidation, immerse it in a potassium fluozirconate solution at 80 - 90 °C for 30 - 60 minutes to generate ZrO2 nanoparticles in the pores of the micro - arc oxidation layer.

[0035] As a further optimized solution of the present invention, the anisotropy regulation treatment in step six specifically includes:

[0036] Crystal orientation calibration: Determine the main texture direction of the aluminum alloy sheet through EBSD detection;

[0037] Directional pre - strain loading: Apply a tensile pre - strain of 3 - 8% along the main texture direction, and control the strain rate to 0.001 - 0.01 s -1 ;

[0038] Dynamic recovery treatment: Immediately perform a short - time annealing at 200 - 250 °C for 30 minutes after pre - strain to activate the dislocation climb mechanism.

[0039] As a further optimization solution of the present invention, the elimination of the composite residual stress in step seven specifically includes:

[0040] Cryogenic treatment stage: Immerse the workpiece in liquid nitrogen for 0.5 - 2 hours to cause lattice contraction to generate reverse stress;

[0041] Ultrasonic vibration loading: Apply ultrasonic waves with a frequency of 20 - 40 kHz and an amplitude of 5 - 15 μm synchronously during the cryogenic process, and the vibration direction is parallel to the extension direction of the heat dissipation teeth;

[0042] Step - by - step warming: Heat up to room temperature at a rate of 3 °C / min, and then keep it at 100 °C for 30 minutes to eliminate the thermo - elastic stress.

[0043] As a further optimization solution of the present invention, the intelligent process parameter optimization in step eight specifically includes:

[0044] Data acquisition module: Real - time monitor the process parameters of temperature, magnetic field strength, and deformation;

[0045] Machine learning model: Establish the prediction relationship between process parameters and mechanical properties by using the XGBoost algorithm;

[0046] Feedback execution module: Automatically adjust the fluctuation range of the aging temperature by ±1 - 3 °C and the magnetic field strength by ±0.05 T according to the prediction results.

[0047] As a further optimization solution of the present invention, it further includes a composite surface treatment process;

[0048] Anodic oxidation treatment is carried out on the surface of the micro - arc oxidation layer to form a double - layer protection structure, which specifically includes:

[0049] The anodic oxidation electrolyte contains 150 - 200 g / L of sulfuric acid, 10 - 20 g / L of oxalic acid, and the temperature is 18 - 25 °C;

[0050] The DC voltage is 15 - 20 V, the treatment time is 30 - 60 minutes, and a porous oxide layer with a thickness of 5 - 10 μm is formed;

[0051] The sealing treatment uses a nickel salt solution, the temperature is 80 - 90 °C, and the micropores are sealed to improve the corrosion resistance.

[0052] The above - mentioned technical solution of the present invention has the following beneficial technical effects:

[0053] 1. Through gradient - controlled solution treatment, the present invention fully dissolves the β phase, inhibits abnormal grain growth, controls the gradient distribution of vacancy concentration, provides a good foundation for the precipitation of subsequent strengthening phases, and the two - stage aging treatment promotes the uniform nucleation of GP zones and the dispersion distribution of θ' phases, improving the strength and toughness of the alloy;

[0054] 2. The present invention uses electromagnetic-assisted shape correction treatment, suppresses thermal stress deformation by means of alternating magnetic fields and asymmetric air cooling, and combines residual stress elimination with cryogenic and ultrasonic vibration treatments to effectively eliminate residual stress, improve dimensional stability and fatigue life.

[0055] 3. The present invention generates an alumina layer through micro-arc oxidation surface treatment, enhances corrosion resistance by in-situ sealing and strengthening, and forms a double-layer protection structure through composite surface treatment processes to further improve corrosion resistance and wear resistance.

[0056] 4. The present invention optimizes intelligent process parameters based on machine learning algorithms, monitors and adjusts process parameters in real time to ensure precise control of the heat treatment process and steadily improve the properties of the alloy. Brief Description of the Drawings

[0057] Figure 1 It is a flowchart of a high-efficiency tooth radiator aluminum alloy strengthening and toughening heat treatment method proposed by the present invention. Detailed Embodiments

[0058] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following descriptions, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0059] As Figure 1 shown, a high-efficiency tooth radiator aluminum alloy strengthening and toughening heat treatment method proposed by the present invention includes the following steps:

[0060] Step 1: Gradient temperature-controlled solution treatment, including at least two different temperature stages;

[0061] Step 2: Electromagnetic-assisted shape correction treatment, applying an alternating magnetic field during the cooling process;

[0062] Step 3: Two-stage aging treatment, including high-temperature primary aging and low-temperature secondary aging;

[0063] Step 4: Pulse aging strengthening, adopting a periodic temperature fluctuation mode;

[0064] Step 5: Micro-arc oxidation surface treatment, generating an alumina layer in the electrolyte;

[0065] Step 6: Anisotropy regulation treatment, applying a directional pre-strain;

[0066] Step 7: Composite residual stress elimination, combining cryogenic and ultrasonic vibration treatments;

[0067] Step 8: Intelligent process parameter optimization, dynamically adjusting treatment parameters based on machine learning algorithms.

[0068] In this embodiment, the gradient temperature-controlled solution treatment in step one specifically includes:

[0069] High-temperature phase dissolution stage: The aluminum alloy workpiece is heated to 520 - 540°C at a rate of 8 - 12°C / min, and kept at this temperature for 20 - 40 minutes under a nitrogen protection atmosphere to completely dissolve the β phase;

[0070] Select an aluminum alloy workpiece that meets the requirements of a high-power tooth radiator, place it in a heating device with precise temperature control and atmosphere control functions, and heat it at a rate of 8 - 12°C / min. This heating rate has been verified by a large number of experiments. It can not only ensure that the internal structure of the aluminum alloy is fully heated, but also prevent abnormal tissue transformation caused by too fast heating. After heating to 520 - 540°C, keep it at this temperature for 20 - 40 minutes under a nitrogen protection atmosphere. The inertness of nitrogen can effectively isolate oxygen, prevent the aluminum alloy from being oxidized at high temperatures, and at the same time create a stable environment for the complete dissolution of the β phase. During this process, the β phase gradually dissolves into the solid solution, and the decomposed solute atoms are evenly distributed in the matrix, reserving key elements for subsequent age hardening;

[0071] Medium-temperature grain boundary regulation stage: Cool down to 470 - 490°C at a rate of ≤5°C / min, switch to an argon atmosphere and keep it at this temperature for 30 - 60 minutes to inhibit abnormal grain growth;

[0072] After the high-temperature phase dissolution is completed, cool down slowly to 470 - 490°C at a rate not exceeding 5°C / min. During the cooling process, switch to an argon atmosphere. Argon has a relatively large atomic radius and can form a barrier at the grain boundaries, effectively inhibiting abnormal grain growth. Keep it at this temperature for 30 - 60 minutes. During this period, use equipment such as a metallographic microscope to observe the grain changes in real time to ensure that the grain size is effectively controlled. The refined grains can significantly improve the strength and toughness of the alloy;

[0073] Gradient cooling stage: Adopt a segmented cooling mode. First, cool down to 300°C at a rate of 15 - 20°C / min, and then cool down to room temperature at a rate of ≤3°C / min to control the gradient distribution of vacancy concentration;

[0074] Adopt a segmented cooling mode. First, cool down to 300°C at a relatively fast rate of 15 - 20°C / min. The rapid cooling can fix the tissue state formed at high temperatures and avoid adverse tissue transformation during the cooling process. Subsequently, cool down to room temperature at a rate not exceeding 3°C / min. This segmented cooling method will form a gradient of vacancy concentration inside the aluminum alloy. It can be observed by using microscopic detection techniques such as atom probe tomography that the vacancies are orderly distributed during the slow cooling process, providing favorable conditions for the uniform precipitation of strengthening phases during subsequent aging;

[0075] In this embodiment, the electromagnetic-assisted shape correction treatment in step two specifically includes:

[0076] Magnetic field parameter setting: When the workpiece temperature drops to 250 - 300 °C, apply a transverse alternating magnetic field of 0.3 - 0.8 T, with a frequency of 10 - 30 kHz, and the magnetic field direction forms an angle of 45 - 90° with the arrangement direction of the heat dissipation teeth;

[0077] This combination of magnetic field parameters can, through simulation calculations and actual tests, enable the magnetic field to fully interact with the dislocations inside the aluminum alloy, hinder the movement of dislocations, and inhibit thermal stress deformation;

[0078] Dynamic field strength adjustment: According to the feedback of infrared temperature measurement, reduce the magnetic field strength at a ratio of ΔB = 0.1 T / 50 °C until the workpiece temperature ≤ 150 °C;

[0079] With the help of a high-precision infrared thermometer, the workpiece temperature is monitored in real time. According to the feedback results, the magnetic field strength is reduced at a ratio of ΔB = 0.1 T / 50 °C until the workpiece temperature is not higher than 150 °C. This dynamic adjustment method ensures that the shape correction effect of the magnetic field on the aluminum alloy is always in the best state at different temperature stages, guaranteeing the stability of the shape correction effect;

[0080] Directional cooling control: Combining with the magnetic field application direction, adopt an asymmetric air-cooling system, and the cooling rate in the tooth top area is 20 - 30% faster than that in the tooth root area to inhibit thermal stress deformation;

[0081] In the design of the air-cooling device, by adjusting parameters such as the outlet position and wind speed of the air outlet, the cooling rate in the tooth top area is 20 - 30% faster than that in the tooth root area. Use a thermal imager to monitor the surface temperature distribution of the workpiece during the cooling process to ensure that the thermal stress is effectively reduced and the shape stability of the aluminum alloy workpiece is maintained.

[0082] In this embodiment, the double-stage aging treatment in step three specifically includes:

[0083] Formation of primary GP zones: Age at 180 - 200 °C for 1.5 - 2.5 hours, and introduce 5 - 10 vol.% nitrogen for protection to promote the uniform nucleation of solute atom clusters GP zones;

[0084] Nitrogen can reduce the interference of impurity atoms on the solute atom clustering process, promote the aggregation of solute atoms to form uniform GP zones, observe the formation of GP zones through a transmission electron microscope to ensure their uniform distribution, and provide sufficient cores for the precipitation of θ' phases during the secondary aging;

[0085] Controlled pressure during the transition stage: Apply a hydrostatic pressure of 0.1 - 0.5 MPa to the workpiece during the natural cooling process to 150 - 170 °C to eliminate microvoids;

[0086] Under the action of pressure, the microvoids inside the alloy are squeezed and closed, improving the density of the alloy and enhancing the mechanical properties of the alloy;

[0087] Secondary θ' phase precipitation: Maintain the temperature at 150 - 170 °C in the aging furnace for 4 - 6 hours, and turn on the ultrasonic vibration at 28 kHz and an amplitude of 10 μm every 1 hour to promote the dispersion distribution of the θ' phase, Al2Cu;

[0088] The vibration of ultrasonic waves can promote atomic diffusion, making the θ' phase (Al2Cu) more evenly dispersed in the aluminum alloy matrix. Observe the distribution state of the θ' phase through a scanning electron microscope to evaluate the strengthening effect.

[0089] In this embodiment, the pulse aging strengthening in step four specifically includes:

[0090] Temperature fluctuation programming: Set the aging temperature to fluctuate within the range of the target value ±8 - 12 °C, with a single cycle duration of 10 - 20 minutes and a total number of cycles of 10 - 30 times;

[0091] By simulating the effects of different temperature fluctuation parameters on the diffusion of solute atoms and the formation of strengthening phases, it is determined that this parameter range can effectively promote the redistribution of solute atoms and form fine and uniform strengthening phases;

[0092] Dynamic compensation control: Automatically adjust the temperature fluctuation amplitude according to the on-line monitoring results of resistivity;

[0093] Use a high-precision resistivity measuring instrument to on-line monitor the change of resistivity of the aluminum alloy during aging. Since the resistivity is closely related to the internal structure state of the alloy, automatically adjust the temperature fluctuation amplitude according to the monitoring results to ensure the stable progress of the aging process and make the alloy performance reach the best;

[0094] Gradient termination mechanism: In the last 3 cycle periods, linearly reduce the temperature fluctuation amplitude to ±2 °C to reduce the sudden change of interface energy;

[0095] This gradient termination method can reduce the change of interface energy caused by temperature mutation and ensure the stability of the alloy performance.

[0096] In this embodiment, the micro-arc oxidation surface treatment in step five specifically includes:

[0097] Electrolyte preparation: Use an aqueous electrolyte containing 10 - 20 g / L of sodium silicate, 5 - 15 g / L of sodium dihydrogen phosphate, and 1 - 5 g / L of potassium hydroxide, and maintain the pH value at 11 - 13;

[0098] Pulse discharge treatment: Take the aluminum alloy workpiece as the anode, put it into the electrolyte, apply a bipolar pulse voltage of 400 - 500 V, with a positive pulse width of 100 - 200 μs, a negative pulse width of 50 - 100 μs, and a frequency of 500 - 1000 Hz. Under the action of the pulse voltage, micro-arc discharge occurs on the surface of the aluminum alloy to generate an alumina layer. By adjusting the pulse parameters, control the growth rate and quality of the alumina layer;

[0099] In-situ sealing hole strengthening: After oxidation is completed, immerse it in a potassium fluozirconate solution at 80 - 90 °C for 30 - 60 minutes to generate ZrO2 nanoparticles in the pores of the micro-arc oxidation layer.

[0100] In this embodiment, the anisotropy regulation treatment in step six specifically includes:

[0101] Crystal orientation calibration: Determine the main texture direction of the aluminum alloy sheet by EBSD detection;

[0102] Directional pre-strain loading: Apply a 3 - 8% tensile pre-strain along the main texture direction, and control the strain rate to be 0.001 - 0.01 s -1 ;

[0103] Dynamic recovery treatment: Immediately perform short-time annealing at 200 - 250 °C for 30 minutes after pre-strain to activate the dislocation climb mechanism.

[0104] In this embodiment, the composite residual stress elimination in step seven specifically includes:

[0105] Deep cryogenic treatment stage: Immerse the workpiece in liquid nitrogen for 0.5 - 2 hours to generate reverse stress due to lattice contraction;

[0106] Ultrasonic vibration loading: Synchronously apply ultrasonic waves at 20 - 40 kHz with an amplitude of 5 - 15 μm during the deep cryogenic process, and the vibration direction is parallel to the extension direction of the heat dissipation teeth;

[0107] Stepwise warming: Heat up to room temperature at a rate of 3 °C / min, and then keep it at 100 °C for 30 minutes to eliminate the thermo-elastic stress.

[0108] In this embodiment, the intelligent process parameter optimization in step eight specifically includes:

[0109] Data acquisition module: Real-time monitor process parameters such as temperature, magnetic field strength, and deformation;

[0110] Machine learning model: Establish a prediction relationship between process parameters and mechanical properties using the XGBoost algorithm;

[0111] Feedback execution module: Automatically adjust the fluctuation range of the aging temperature by ±1 - 3 °C and the magnetic field strength by ±0.05 T according to the prediction results.

[0112] In this embodiment, it also includes a composite surface treatment process;

[0113] Perform anodic oxidation treatment on the surface of the micro-arc oxidation layer to form a double-layer protection structure, specifically including:

[0114] The anodic oxidation electrolyte contains 150 - 200 g / L of sulfuric acid, 10 - 20 g / L of oxalic acid, and the temperature is 18 - 25 °C;

[0115] The DC voltage is 15-20V, the processing time is 30-60 minutes, and a 5-10μm porous oxide layer is generated;

[0116] The sealing treatment uses a nickel salt solution at a temperature of 80-90°C to seal the micropores and improve corrosion resistance.

[0117] The specific working principle of the present invention is as follows:

[0118] In the high-temperature phase dissolution stage, the aluminum alloy is heated to 520-540℃ to allow the β phase to fully dissolve into the solid solution. The solute atoms decomposed from the β phase prepare for subsequent aging strengthening. In the medium-temperature grain boundary regulation stage, the temperature is reduced to 470-490℃, and the protective atmosphere is replaced with argon. This can inhibit the abnormal growth of grains and make the grains smaller, just like refining large particles, thereby improving the strength and toughness of the alloy. In the gradient cooling stage, it is first quickly cooled to 300℃, and then slowly cooled to room temperature. This segmented cooling method will form a vacancy concentration gradient inside the aluminum alloy, which plans the route for the precipitation of the strengthening phase in the subsequent aging process, so that the strengthening phase can precipitate more evenly.

[0119] When the temperature of the aluminum alloy workpiece drops to 250-300℃, a transverse alternating magnetic field is applied to it. The magnetic field will interact with the aluminum alloy to hinder the movement of internal dislocations, just like setting up roadblocks to prevent dislocated atoms from running around, thereby suppressing thermal stress deformation. Moreover, the magnetic field strength can be dynamically adjusted according to temperature feedback. As the temperature decreases, the magnetic field strength also decreases proportionally until the workpiece temperature is no higher than 150℃. This ensures that the correction effect is always stable. In addition, an asymmetric air cooling system is used in conjunction with the magnetic field direction to allow the tooth top to cool 20-30% faster than the tooth root, further reducing thermal stress and making the shape of the aluminum alloy workpiece more stable.

[0120] In the primary aging stage, the aluminum alloy is placed in an environment of 180-200℃ for 1.5-2.5 hours, and 5-10vol.% nitrogen is introduced, so that the solute atoms can gather to form uniform GP zones. These GP zones provide cores for the precipitation of θ' phase during the secondary aging. In the transition stage of natural cooling from 180-200℃ to 150-170℃, 0.1-0.5MPa hydrostatic pressure is applied to the workpiece to make the alloy denser. In the secondary aging, the temperature of 150-170℃ is maintained for 4-6 hours, and ultrasonic vibration is turned on every 1 hour during this period to make the θ' phase evenly dispersed in the aluminum alloy, enhancing the strengthening effect.

[0121] Let the aging temperature fluctuate periodically within a range of 8 - 12 °C above and below the target value. This kind of fluctuation can make solute atoms diffuse and redistribute in the aluminum alloy, forming finer and more uniform strengthening phases, just like stirring the originally unevenly distributed atoms evenly. Automatically adjust the amplitude of temperature fluctuation by online monitoring the resistivity to ensure the stability and consistency of the aging process. In the last 3 cycle periods, slowly reduce the amplitude of temperature fluctuation to ±2 °C, which can reduce the sudden change of interface energy and make the alloy properties more stable;

[0122] Put the aluminum alloy in an electrolyte containing sodium silicate, sodium dihydrogen phosphate, and potassium hydroxide, and apply a bipolar pulse voltage of 400 - 500 V. Micro-arc discharge will occur on the surface of the aluminum alloy, thereby generating an alumina layer. This alumina layer is like putting a protective coat on the aluminum alloy. After oxidation is completed, immerse the aluminum alloy in a potassium fluozirconate solution, and the solution will react with the pores to generate ZrO2 nanoparticles, further improving the corrosion resistance of the aluminum alloy;

[0123] First, use EBSD detection to find the main texture direction of the aluminum alloy sheet, and then apply a tensile pre-strain of 3 - 8% along this direction to make the alloy anisotropic, just like "directionally growing" the alloy. After the pre-strain, immediately perform short-time annealing at 200 - 250 °C for 30 minutes to activate the dislocation climb mechanism, eliminate part of the internal stress, and make the anisotropic properties of the alloy better;

[0124] Put the aluminum alloy workpiece in liquid nitrogen for 0.5 - 2 hours. The low temperature will cause the lattice to contract and generate reverse stress. Apply ultrasonic waves of 20 - 40 kHz while cryogenic cooling to promote dislocation movement and accelerate stress relaxation. Then, heat it to room temperature at a rate of 3 °C / min, and then keep it at 100 °C for 30 minutes to completely eliminate the thermo-elastic stress and greatly reduce the internal stress of the aluminum alloy;

[0125] Finally, use the data acquisition module to collect process parameters such as temperature, magnetic field strength, and deformation amount in real time, and then use the XGBoost algorithm to establish a prediction model between these parameters and the mechanical properties of the aluminum alloy. The feedback execution module automatically adjusts the amplitude of temperature fluctuation and magnetic field strength according to the model prediction results to realize the dynamic optimization of the entire heat treatment process and make the properties of the aluminum alloy reach the best.

[0126] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modification examples falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for strengthening and toughening heat treatment of an aluminum alloy for a high-ratio tooth radiator, characterized in that, It includes the following steps: Step 1: Gradient temperature-controlled solution treatment, including at least two different temperature stages; Step 2: Electromagnetic-assisted shape correction treatment, applying an alternating magnetic field during the cooling process; Step 3: Two-stage aging treatment, including high-temperature primary aging and low-temperature secondary aging; Step 4: Pulsed aging strengthening, adopting a periodic temperature fluctuation mode; Step 5: Micro-arc oxidation surface treatment, generating an alumina layer in the electrolyte; Step 6: Anisotropy regulation treatment, applying a directional pre-strain; Step 7: Composite residual stress elimination, combining cryogenic and ultrasonic vibration treatments; Step 8: Intelligent process parameter optimization, dynamically adjusting processing parameters based on machine learning algorithms.

2. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 1, characterized in that, The gradient temperature-controlled solution treatment in Step 1 specifically includes: High-temperature phase dissolution stage: Heating the aluminum alloy workpiece at a rate of 8 - 12 °C / min to 520 - 540 °C, and holding it for 20 - 40 minutes under a nitrogen protection atmosphere to completely dissolve the β phase; Medium-temperature grain boundary regulation stage: Cooling it at a rate of ≤5 °C / min to 470 - 490 °C, switching to an argon atmosphere and holding it for 30 - 60 minutes to inhibit abnormal grain growth; Gradient cooling stage: Adopting a segmented cooling mode, first quickly cooling it at a rate of 15 - 20 °C / min to 300 °C, and then slowly cooling it at a rate of ≤3 °C / min to room temperature to control the gradient distribution of vacancy concentration.

3. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 2, characterized in that, The electromagnetic-assisted shape correction treatment in Step 2 specifically includes: Magnetic field parameter setting: When the workpiece temperature drops to 250 - 300 °C, applying a transverse alternating magnetic field of 0.3 - 0.8 T, with a frequency of 10 - 30 kHz, and the magnetic field direction forms an angle of 45 - 90° with the arrangement direction of the heat dissipation teeth; Dynamic field strength adjustment: According to the infrared temperature measurement feedback, reducing the magnetic field strength at a ratio of ΔB = 0.1 T / 50 °C until the workpiece temperature ≤150 °C; Directional cooling control: Combining the magnetic field application direction, adopting an asymmetric air-cooling system, with the cooling rate in the tooth tip area 20 - 30% faster than that in the tooth root area to inhibit thermal stress deformation.

4. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 3, characterized in that, The two-stage aging treatment in Step 3 specifically includes: Formation of primary GP zones: Aging at 180 - 200 °C for 1.5 - 2.5 hours, introducing 5 - 10 vol.% nitrogen for protection to promote the uniform nucleation of solute atom clusters GP zones; Pressure control in the transition stage: Applying a hydrostatic pressure of 0.1 - 0.5 MPa to the workpiece during the natural cooling process to 150 - 170 °C to eliminate microvoids; Precipitation of secondary θ' phases: Maintaining the temperature at 150 - 170 °C in the aging furnace for 4 - 6 hours, and turning on the ultrasonic vibration at 28 kHz and 10 μm amplitude every 1 hour to promote the dispersion distribution of θ' phases, Al2Cu.

5. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 4, characterized in that, The pulsed aging strengthening in Step 4 specifically includes: Temperature fluctuation programming: Setting the aging temperature to fluctuate within the range of the target value ±8 - 12 °C, with a single-cycle duration of 10 - 20 minutes and a total number of cycles of 10 - 30 times; Dynamic compensation control: Automatically adjusting the temperature fluctuation amplitude according to the on-line resistivity monitoring results; Gradient termination mechanism: In the last 3 cycle periods, linearly reducing the temperature fluctuation amplitude to ±2 °C to reduce the sudden change of interface energy.

6. A high-strength and tough heat treatment method for an aluminum alloy of a high-ratio gear radiator according to claim 5, characterized in that The micro-arc oxidation surface treatment in Step 5 specifically includes: Electrolyte preparation: Use an aqueous electrolyte containing 10 - 20 g / L of sodium silicate, 5 - 15 g / L of sodium dihydrogen phosphate, and 1 - 5 g / L of potassium hydroxide, and maintain the pH value at 11 - 13; Pulse discharge treatment: Apply a bipolar pulse voltage of 400 - 500 V, with a positive pulse width of 100 - 200 μs, a negative pulse width of 50 - 100 μs, and a frequency of 500 - 1000 Hz; In-situ sealing and strengthening: After oxidation, immerse it in a potassium fluozirconate solution at 80 - 90 °C for 30 - 60 minutes to generate ZrO2 nanoparticles in the pores of the micro-arc oxidation layer.

7. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 6, characterized in that, The anisotropy regulation treatment in Step 6 specifically includes: Crystal orientation calibration: Determine the main texture direction of the aluminum alloy sheet by EBSD detection; Directional pre-strain loading: Apply a 3 - 8% tensile pre-strain along the main texture direction, and control the strain rate to 0.001 - 0.01 s-1; Dynamic recovery treatment: Immediately perform a short-time annealing at 200 - 250 °C for 30 minutes after pre-strain to activate the dislocation climb mechanism.

8. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 7, characterized in that The composite residual stress elimination in Step 7 specifically includes: Cryogenic treatment stage: Immerse the workpiece in liquid nitrogen for 0.5 - 2 hours to generate reverse stress due to lattice contraction; Ultrasonic vibration loading: Synchronously apply ultrasonic waves of 20 - 40 kHz during cryogenic treatment, with an amplitude of 5 - 15 μm, and the vibration direction parallel to the extension direction of the heat dissipation teeth; Stepwise warming: After heating to room temperature at a rate of 3 °C / min, then hold at 100 °C for 30 minutes to eliminate thermo-elastic stress.

9. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 8, characterized in that The intelligent process parameter optimization in Step 8 specifically includes: Data acquisition module: Real-time monitor the process parameters of temperature, magnetic field strength, and deformation amount; Machine learning model: Establish a prediction relationship between process parameters and mechanical properties using the XGBoost algorithm; Feedback execution module: Automatically adjust the fluctuation range of the aging temperature by ±1 - 3 °C and the magnetic field strength by ±0.05 T according to the prediction results.

10. A high-strength and tough heat treatment method for aluminum alloy of a high-ratio tooth radiator according to claim 9, characterized in that, It also includes a composite surface treatment process; Perform anodic oxidation treatment on the surface of the micro-arc oxidation layer to form a double-layer protection structure, specifically including: The anodic oxidation electrolyte contains 150 - 200 g / L of sulfuric acid and 10 - 20 g / L of oxalic acid, and the temperature is 18 - 25 °C; The DC voltage is 15 - 20 V, the treatment time is 30 - 60 minutes, and a 5 - 10 μm porous oxidation layer is generated; The sealing treatment uses a nickel salt solution, and the temperature is 80 - 90 °C to seal the micropores and improve the corrosion resistance.

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