Method for regulating and controlling structure and performance of friction stir additive aluminum alloy component

Abstract

The invention relates to a method for regulating and controlling the structure and performance of a friction stir additive aluminum alloy component. A staged electric pulse heat treatment method of a local electric loop and follow-up scanning is adopted, an adaptive function regulation and control model of pulse frequency, pulse width and current density is established based on the real-time thickness of the component, and integrated control of destressing, rapid solid solution and aging treatment is achieved. Carrying out thickness self-adaptive low-temperature destressing by utilizing the cooperation of low-frequency pulse and electronic wind power; flash solid solution is carried out by utilizing high-frequency skin effect and thickness function response, and quenching is realized through accompanying cooling; and carrying out gradient adaptive scanning aging. Through dynamic matching of energy input and local heat capacity, the problem of uneven heat treatment of the variable-cross-section component is effectively solved, the period can be remarkably shortened without macroscopic plastic deformation, the deformation risk is reduced, abnormal growth of grains is inhibited while the precipitation strengthening effect is recovered, and the specific fine grain structure of the additive is reserved; the comprehensive performance and dimensional stability of the component are improved.

Description

Technical Field

[0001] This invention relates to a method for regulating the microstructure and properties of friction stir additive aluminum alloy components, belonging to the field of post-processing and performance regulation technology in metal additive manufacturing. Background Technology

[0002] Aluminum alloys, due to their low density, high specific strength, corrosion resistance, and excellent electrical and thermal conductivity, have been widely used in aerospace, rail transportation, and defense equipment. As high-end equipment continues to demand lighter, larger, and more integrated components, traditional casting, forging, machining, and other subtractive manufacturing processes are increasingly unable to meet the requirements in terms of material utilization, forming complexity, and performance consistency. While melt additive manufacturing possesses complex forming capabilities, the melting / solidification process is prone to metallurgical defects such as hot cracking, porosity, compositional segregation, and elemental loss, posing significant challenges to component performance control.

[0003] The novel friction stir additive manufacturing technology utilizes the frictional heat generated by intense plastic deformation to achieve plastic flow and layer-by-layer deposition of additive raw materials within a temperature range below the melting point (approximately 50-90% of the melting point). This avoids melting-solidification defects and yields additive components with both high density and good interfacial bonding. The friction stir additive manufacturing process features low heat input, low residual stress, and high process flexibility, demonstrating significant application potential in the rapid fabrication of large-size complex aluminum alloy components.

[0004] The complex thermo-mechanical coupling effects in the friction stir additive manufacturing process have led to new technical bottlenecks. Existing research indicates that when heat-treated aluminum alloys are strengthened through friction stir additive manufacturing, almost all of the main strengthening phase dissolves, resulting in severe softening of the prepared aluminum alloy components. The tensile strength of these components is only 50-60% of the base material, making them unsuitable for engineering applications. The multi-layered cumulative thermo-mechanical coupling during the additive manufacturing process causes repeated heating and deformation of the previously deposited layers, hindering complete dynamic recrystallization and leaving high dislocation density and stored energy within the fine grains. As the main strengthening phase dissolves and the non-strengthening phase coarsens, the pinning effect of the second phase on grain boundaries gradually weakens. The superposition of shear force, upsetting force, and non-uniform temperature field during the additive manufacturing process introduces a complex tensile and compressive residual stress field within the additive component, leading to severe warping deformation during subsequent processing.

[0005] To address the aforementioned issues, existing technologies often employ traditional furnace stress relief treatment, homogenization annealing, hot deformation strengthening, and solution aging processes to restore the performance of friction stir additive manufacturing components. While these methods can restore strength to some extent, they have the following limitations: (1) High processing temperatures and long holding times can easily lead to secondary recrystallization and abnormal grain growth, damaging the original fine-grained structure in the additive region; (2) Repeated heating-holding-cooling cycles cause repeated superposition of internal thermal stress, which can easily lead to dimensional deformation, especially for complex thin-walled components; (3) Thermal cycling during the additive process leads to the dissolution and coarsening of the strengthening phase. Shortening the heat treatment time to avoid grain growth can result in insufficient solute re-dissolution, making it difficult to obtain peak strength. Therefore, how to control the microstructure and properties of heat-treated aluminum alloy components produced by friction stir additive manufacturing, fully restore and improve their mechanical properties, suppress abnormal grain growth, and maximize the preservation of the forming shape and dimensional accuracy of the additive components is a pressing problem to be solved in the field of friction stir additive manufacturing. Summary of the Invention

[0006] To address the problems of abnormal grain growth, dimensional deformation, and non-uniform microstructure / properties in friction stir additive manufacturing (FSM) components caused by existing furnace-based overall heat treatment, this invention proposes a method for controlling the microstructure and properties of FSM aluminum alloy components. By introducing electric pulse coupled heating technology into the post-additive heat treatment process, it achieves integrated control of stress relief, short-time solution treatment, and age strengthening. This significantly improves the strength, toughness, and stability of the additive components without requiring macroscopic thermal deformation, while simultaneously suppressing abnormal grain growth in the additive region and maintaining a fine and uniform additive microstructure. This solves the problems of long processing cycles, large dimensional deformation, and microstructure coarsening inherent in existing technologies. This invention abandons the traditional "overall energization" mode and adopts a "local high-energy injection + dynamic scanning" strategy. It utilizes the skin effect and non-thermal effects of high-energy electric pulses for depth control, enabling online or offline high-performance processing of components.

[0007] A method for regulating the microstructure and properties of friction stir additive aluminum alloy components, comprising the following specific steps: (1) The additive raw materials are deposited on an aluminum alloy substrate by friction stir additive manufacturing to obtain an aluminum alloy additive component with an equiaxed fine grain structure; (2) First-stage thickness adaptive low-temperature stress relief treatment: Using an electrical pulse system equipped with thickness monitoring or position feedback, the aluminum alloy additive component is scanned row by row or layer by layer; during the scanning process, the real-time thickness of the scanned area is monitored. t The electrical pulse parameters are dynamically adjusted, and a low-frequency high-energy pulse current is applied for stress relief. In this stage, the synergistic effect of the Joule heating effect and the electron wind (electroplastic effect) excited by the low-frequency high-energy pulse current is used to reduce the dislocation motion barrier and promote the movement and annihilation of dislocations at a lower temperature (150~250℃), thereby releasing residual stress without recrystallization. (3) Second stage rapid solution treatment and quenching: The area of ​​the aluminum alloy additive component after the residual stress is released is scanned. During the scanning process, a high-frequency high-energy pulsed current is applied. The significant skin effect and high-energy Joule heating effect of the high-frequency high-energy pulsed current are used to rapidly heat the area of ​​different thicknesses to the solution temperature range and maintain a constant relative thermal effect depth to achieve flash re-dissolution of solute atoms. Then, rapid quenching is performed using a follow-up cooling device to form a supersaturated solid solution. (4) Third-stage gradient adaptive aging treatment: Apply a third-stage pulse current to the quenched aluminum alloy component to perform global or local scanning aging treatment; the pulse frequency of the aging treatment f 1. Pulse width τ3 and effective current density J 3 are based on thickness t By establishing a continuous functional relationship for adjustment, a uniform precipitation driving force is maintained in cross-sections of different thicknesses within a temperature range of 100~180℃, and the enhanced phase is precipitated by air cooling to room temperature.

[0008] Preferably, the additive material in step (1) is rod, wire, powder or waste of the above additive materials.

[0009] Preferably, to ensure that the current can effectively penetrate the cross-section of the component at different thicknesses and match its thermal capacity characteristics, the parameters of the low-frequency high-energy pulse current in step (2) are adjusted in real time according to the following functional relationship: pulse frequency f 1 and thickness t They are negatively correlated and satisfy a functional relationship. f 1(t)=C1 / t With the thickness of the component t The increase in current requires a decrease in frequency to increase the penetration depth of the current, ensuring that the current covers the entire component cross-section rather than just flowing through the surface, thus achieving full-volume stress relief; the constant C1 ranges from 2000 to 5000 Hz·mm, and the pulse frequency... f The adjustment range of 1 is usually 10~300Hz; Pulse width τ1 and thickness t They are positively correlated and satisfy the functional relationship τ1(t) = k 1· t +τ min1 By linearly increasing the pulse width, the energy injection time and electron wind duration of a single pulse are prolonged to match the thermal response characteristics of the material; where the coefficient k 1 is a positive number, and the control range of τ1 is 500~1500μs; Effective current density J 1 and thickness t They are positively correlated and satisfy a functional relationship. J 1(t)=a 1· t + J min1 This is to compensate for the increased volumetric heat conduction loss as the thickness increases, and to maintain the energy threshold required for dislocation activation.

[0010] Preferably, the scanning speed in step (2) is 100~500mm / min, and the temperature of the local area in contact with the aluminum alloy additive component is 150~250℃ by adjusting the duty cycle of the pulse current.

[0011] Preferably, the parameters of the high-frequency, high-energy pulse current in step (3) are controlled according to the following functional relationship: pulse frequency f 1. Following the matching principle of skin depth and thickness, satisfying the power-law function relationship. f 2(t)=C2· t -α The constant C2 ranges from 5000 to 15000 Hz·mm, and the exponent... α Values ​​range from 1.0 to 2.0, pulse frequency. f The adjustment range of 2 is 10Hz~2500Hz; Preferably, for thin-walled areas, the system automatically outputs high frequency (e.g., >1000Hz) to concentrate the current on the surface and heat the core by means of heat conduction, preventing the thin wall from melting due to insufficient thermal resistance; for thick-walled areas, the system automatically reduces the frequency and increases the skin depth to achieve deep heating.

[0012] Preferably, in step (3), the pulse width τ2 of the high-frequency, high-energy pulse current satisfies the functional relationship τ2(t) = k 2· t +τ min2 To match the thermal relaxation time at different thicknesses and prevent insufficient heat accumulation or overheating; coefficient k 2 is a positive number, and the τ2 control range is 100~1200μs; Preferably, the effective current density of the high-frequency, high-energy pulse current in step (3) is... J 2. Satisfies the functional relationship J 2(t)= a 2· t + J min2 The control range is 5~120A / mm 2 .

[0013] Preferably, the peak temperature of the solution temperature range in step (3) is the solidus temperature of the alloy ( T s90%~98% of the total; the scanning mode is a pause-pulse-move step scan or a low-speed continuous scan with a speed of 10~500mm / min.

[0014] Preferably, the parameters of the pulse current in step (4) are controlled according to the following functional relationship: Pulse current pulse frequency f 3 is set to 10Hz~200Hz, and varies with thickness. t Increase and decrease, satisfying a functional relationship f 3(t) = C3 / t + f min3 ; Preferably, in step (4), the effective current density of the pulse current is... J 3. Satisfy the functional relationship J 3(t)= a 3· t + J min3 The control range is 5~100A / mm 2 To compensate for the heat dissipation of large-volume components; Preferably, the pulse current pulse width τ3 satisfies the functional relationship τ3(t) = k 3· t +τ min3 The control range is 100~800μs to enhance the thermal depth of a single pulse.

[0015] Preferably, in step (4), the aging temperature is controlled at 100~180℃ and the cumulative aging time is 10~240min.

[0016] The f (t), t (t) and J The frequency constant C and current density constant in the (t) function a and α and pulse width constant k The preset values ​​are automatically corrected based on different heat-treated and strengthened aluminum alloys (such as aluminum alloys with grades 7075, 2219, 6061, etc.).

[0017] The automatic correction is achieved by the control system calculating the resistivity correction factor in real time based on a preset function of the reference material. K r Enthalpy correction factor K th and thermal diffusivity correction factor K a Automatically reconfigurable pulse parameter control function.

[0018] The frequency constant C is based on K r= r target / r ref Perform linear correction ( C new = C ref · K r ).

[0019] The current density constant a and α based on Nonlinear corrections are applied to the differences in solution treatment temperature.

[0020] The pulse width constant k Based on the ratio of thermal diffusivity K a Perform reverse correction.

[0021] The method of this invention can employ an electrical pulse-controlled alloy microstructure device (see...). Figure 1 The electropulse-controlled alloy microstructure device includes an additive manufacturing worktable, a multi-axis robotic arm 2, a pulse electrode 3, a cooling device 4, an electric pulse generator 5, a temperature acquisition device 6, a control system 7, and a spray quenching device 8. The aluminum alloy additive component is fixedly mounted on the additive manufacturing worktable. The pulse electrode 3, cooling device 4, and spray quenching device 8 are mounted on the multi-axis robotic arm 2. The spray quenching device 8 is located behind the pulse electrode 3. The pulse electrode 3 is electrically connected to the electric pulse generator 5. The temperature acquisition device 6 is located on one side of the additive manufacturing worktable. The multi-axis robotic arm 2, cooling device 4, electric pulse generator 5, temperature acquisition device 6, and spray quenching device 8 are all communicatively connected to the control system 7.

[0022] The electrical pulse generator 5 is used to output pulse current; the pulse electrode 3 is a flexible follower roller electrode, used to establish a local moving electrical circuit on the surface of the aluminum alloy additive component 1 to achieve "local high-energy injection + dynamic scanning" partitioned processing; the cooling device 4 is set inside the pulse electrode 3 or on the electrode bearing part; the multi-axis robotic arm 2 is used to drive the pulse electrode 3 to scan along a predetermined path; the temperature acquisition device 6 is used to acquire the temperature information of the contact area between the pulse electrode 3 and the aluminum alloy additive component in real time; and the control system 7 is used to realize closed-loop control of the processing process.

[0023] The multi-axis robotic arm 2 is used to drive the pulse electrode 3 to perform line-by-line, channel-by-channel, or layer-by-layer scanning. The pulse electrode 3 includes one or more pairs of flexible electrode assemblies and an electrode follow-up loading mechanism. The flexible electrode assembly is an adaptive rolling electrode or a flexible graphite fiber brush electrode. The electrode follow-up loading mechanism is equipped with a spacing adjustment device. Each pair of flexible electrode assemblies is respectively set on the spacing adjustment device to realize the adjustable spacing between the two electrodes. The spacing adjustment range between the two electrodes is 20-500mm to limit the local loop length. The electrode follow-up loading mechanism is a pneumatic or spring floating mechanism that can automatically adjust the normal pressure according to the surface curvature change of the aluminum alloy additive component. The normal pressure is set to 1000-5000N to stabilize the contact state and reduce contact resistance fluctuations.

[0024] The cooling device 4 is used to force-cool the flexible electrode assembly and its contact area with the aluminum alloy additive component. The cooling device 4 includes a circulating water cooling channel, a rotary joint and an external cooling circulation device. The circulating water cooling channel is set inside the electrode shaft of the flexible electrode assembly. The cooling medium is filled in the circulating water cooling channel and circulates. It is used to suppress the temperature rise of the contact surface of the flexible electrode assembly when a continuous high current is applied, reduce the risk of adhesion, ablation and arc damage of the flexible electrode assembly, and ensure stable output and repeatability during long-term scanning.

[0025] The electrical pulse generator 5 is used to output pulse current. The electrical pulse generator 5 is constructed using large-capacity capacitor energy storage or IGBT full-bridge inverter modulation technology and has a constant current output mode. The output pulse waveform is a square wave, an exponentially decaying wave or a unipolar sine wave. Its output capability is: peak voltage 0-100V, peak current 0-5000A, and current rise time less than 50μs.

[0026] The temperature acquisition device 6 is an infrared temperature measurement system or a wireless thermocouple system. The control system 7 is equipped with a high-speed pulse controller and a closed-loop feedback module, which has microsecond-level frequency switching and duty cycle adjustment capabilities. The control system 7 dynamically adjusts the duty cycle and / or pulse frequency of the electric pulse generator 5 according to the real-time temperature fed back by the temperature acquisition device 6, so that the temperature of the scanning area is maintained within the set target range, thereby achieving temperature consistency control during the non-steady-state scanning process.

[0027] The spray quenching device 8 is matched with the scanning path of the pulse electrode 3 and is used to perform rapid cooling of the scanning area after solid solution heating. The spray quenching device 8 is a water mist spraying structure, an air atomization spraying structure, or a cooling roller pressing cooling structure to ensure that the required cooling rate is obtained after solid solution and a supersaturated solid solution is formed, thereby improving the subsequent aging strengthening effect and reducing the risk of heat treatment deformation.

[0028] The beneficial effects of this invention are: (1) This invention breaks through the post-processing bottleneck of large-size components and achieves uniform microstructure and fine grain characteristics throughout the entire domain: It abandons the limitation of traditional electric pulses requiring "overall energization" for large cross-section components, and innovatively adopts the "follow-up local scanning" strategy to reduce the current requirement of tens of thousands of amperes to an industrially feasible range, which is expected to successfully solve the post-processing problem of large-size or complex-shaped additive components; It utilizes the non-thermal effect of electric pulses to promote dislocation annihilation and substructure evolution at lower temperatures, effectively overcoming the problem of abnormal grain growth caused by long-term high-temperature heat treatment in traditional furnace heat treatment, ensuring that the fine equiaxed grain structure unique to additive manufacturing is preserved, and significantly improving the strength and toughness matching of the components; (2) This invention solves the problem of heat treatment deformation and achieves near-net-shape forming with "no macroscopic plastic deformation": In response to the pain point that aluminum alloy thin-walled or slender components are prone to warping deformation during traditional solution water quenching, the instantaneous heating and skin effect of high-energy electric pulses are used to activate atomic diffusion and phase transformation only at the microscale, while the macroscopic components are always in a "cold" or low-temperature state; combined with pulse intermittent self-cooling or accompanying local cooling, the severe release of thermal stress is avoided, and the high dimensional accuracy of the components can be guaranteed without subsequent mechanical correction, truly realizing the dimensional stability of additive components that are "printed as finished products" or "processed as finished products"; (3) Significant energy-saving and high-efficiency advantages and process controllability of the present invention: Compared with the traditional heating furnace heat treatment process that takes tens of hours to heat up and hold, the present invention uses current to directly do work on the metal lattice, with a thermal efficiency of up to 80% or more (traditional furnace heat <30%), shortening the total processing cycle from 20-30 hours to within 2-4 hours, and reducing energy consumption by more than 50%; by precisely adjusting the pulse frequency (50-600Hz), current density and duty cycle, differentiated control of the surface or core depth of the component can be achieved, and overheating and melting can be effectively prevented by strictly limiting the peak temperature. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an electrical pulse-controlled alloy microstructure device. In the figure, 1-friction stir additive manufacturing component, 2-multi-axis robotic arm; 3-pulse electrode, 4-cooling device, 5-electric pulse generator, 6-temperature acquisition device, 7-control system, 8-spray quenching device; Figure 2 Metallographic image of grain morphology of aluminum alloy component produced by electro-pulse treatment and friction stir additive manufacturing in Example 1; Figure 3 Metallographic images of grain morphology of aluminum alloy components processed by traditional methods for comparison example 2. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0031] This invention employs an electrical pulse-controlled alloy microstructure device (see...) Figure 1 The electropulse-controlled alloy microstructure device includes an additive manufacturing worktable, a multi-axis robotic arm 2, a pulse electrode 3, a cooling device 4, an electric pulse generator 5, a temperature acquisition device 6, a control system 7, and a spray quenching device 8. The aluminum alloy additive component 1 is fixedly mounted on the additive manufacturing worktable. The pulse electrode 3, cooling device 4, and spray quenching device 8 are mounted on the multi-axis robotic arm 2. The spray quenching device 8 is located behind the pulse electrode 3. The pulse electrode 3 is electrically connected to the electric pulse generator 5. The temperature acquisition device 6 is located on one side of the additive manufacturing worktable. The multi-axis robotic arm 2, cooling device 4, electric pulse generator 5, temperature acquisition device 6, and spray quenching device 8 are all communicatively connected to the control system 7.

[0032] Example 1: This example uses 7075 aluminum alloy as the processing object; A method for controlling the microstructure and properties of friction stir additive aluminum alloy components, comprising the following specific steps: (1) Using a solid-state stir friction deposition additive manufacturing equipment, 7075-T6 aluminum alloy rods with a diameter of 15mm are used as raw materials. The 7075-T6 aluminum alloy is deposited onto a 7075-T6 aluminum alloy substrate by stir friction deposition to obtain an aluminum alloy additive component with an equiaxed fine grain structure; the aluminum alloy additive component has a single wall structure with dimensions of 300mm (length) × 40mm (width) × 40mm (height) (i.e., thickness). t =40mm); The spindle speed of the solid-phase stirring friction deposition additive manufacturing equipment is 250rpm, the traverse speed of the printing tool is 100mm / min, and the single-layer deposition thickness is 1.5mm; (2) First-stage thickness adaptive stress relief: The aluminum alloy additive component is scanned pass-by-pass using an electrical pulse electrode with an electrode spacing of 40 mm at a scanning speed of 300 mm / min; based on the component thickness... t =40mm, the control system sets the low-frequency high-energy pulse parameters according to the following function, and uses the synergistic effect of electronic wind power and Joule heating to release residual stress at 220℃: The pulse frequency setting constant of the pulse current is C1 = 3000 Hz·mm, which satisfies... f 1( t =3000 / 40=75Hz, pulse width setting coefficient k 1 = 15 μs / mm, constant t min1 =200μs, satisfying t 1( t )=15 40 +200= 800μs; Effective current density J1 Setting coefficients a 1 = 1.0A / mm 3 ,constant J min1 = 10A / mm 2 ,satisfy J 2 (t)= 1.0 40 + 10 = 50 A / mm 2 ; (3) Second stage rapid solution treatment and quenching: The area of ​​the aluminum alloy additive component after residual stress is released is scanned. During the scanning process, a high-frequency, high-energy pulsed current is applied. Utilizing the skin effect and Joule heating effect of the high-frequency, high-energy pulsed current, the scanned area is rapidly heated to the solution temperature range (the peak temperature quickly reaches 450℃, approximately 0.94 ℃). T s The high-frequency, high-energy pulse current is held for a short period of 10 seconds, followed by rapid quenching at a cooling rate greater than 100°C / s using an accompanying water mist spray quenching device. The parameters of the high-frequency, high-energy pulse current are controlled according to the following functional relationship: The pulse frequency setting constant for the pulse current is C2 = 12000 Hz·mm, and the exponent α is... = Version 1.0 satisfies f 2( t )=C2·t -α =12000 / 40=300Hz; Pulse width setting coefficient k 2 = 20 μs / mm, constant t min2 =400μs, satisfying t 1( t )= k 2·t2+ t min2 =20 40 + 400 = 1200 μs; Effective current density J 2 Setting coefficients a 2 = 2.0A / mm 3 ,constant J min2 = 40A / mm 2 ， satisfy J 2 (t)= a 2 · t+J min2= 2.0 40 + 40 = 120A / mm 2 ; The scanning speed was 100 mm / min, and the scanning method was partial scanning. (4) Third stage gradient adaptive aging: A pulsed current is applied to the quenched aluminum alloy component, and the duty cycle of the pulsed current is dynamically adjusted to stabilize the aging temperature at 120℃, with a cumulative aging time of 60 min; the pulse frequency of the aging process... f 3. Pulse width τ3 and effective current density J 3 are based on thickness t A continuous functional relationship was established for adjustment to maintain a uniform precipitation driving force across cross-sections of different thicknesses, resulting in the precipitation of a diffusely distributed strengthening phase upon air cooling to room temperature; the parameters were set as follows: The pulse frequency setting constant of the pulse current is C3 = 4000 Hz·mm, which satisfies... f 3( t ) = 4000 / 40 = 100Hz; Pulse width setting coefficient k 3 = 15 μs / mm, constant t min3 =200μs, satisfying t 3( t )=15 40 + 200 = 800 μs; effective current density J 3 Setting coefficients a 3 = 1.0A / mm 3 ,constant J min3 = 10A / mm 2 ,satisfy J 3 (t)= 1.0 40 + 10 = 50 A / mm 2 .

[0033] Comparative Example 1: The aluminum alloy additive component in this comparative example is the aluminum alloy additive component with equiaxed fine grain structure in step (1) of Example 1, without electrical pulse treatment.

[0034] Comparative Example 2: (using traditional T6 heat treatment process): (1) Stress relief treatment: The aluminum alloy additive component with equiaxed fine grain structure in step (1) of Example 1 is placed in a resistance furnace, heated to 220°C with the furnace, held for 3 hours, and then cooled to room temperature. (2) Solution treatment: Place the aluminum alloy additive component in a resistance furnace, heat it to 460°C, hold it for 2 hours, take the aluminum alloy additive component out of the furnace, and quickly transfer it to water for cooling (water quenching). (3) Aging treatment: The quenched aluminum alloy additive components are placed in an aging furnace and kept at 120°C for 24 hours.

[0035] Metallographic image of grain morphology of aluminum alloy additive component subjected to electro-pulse treatment and friction stir is shown in Example 1. Figure 2 Comparative Example 1: Metallographic image of grain morphology of aluminum alloy additive components processed by traditional method (see Figure 1). Figure 3 Table 1 shows the performance of the aluminum alloy additive component with electro-pulse treatment and the aluminum alloy additive component with conventional treatment in Example 1. Table 1. Performance of conventional methods for treating friction stir aluminum alloy additive components in Example 1 and Comparative Example 2. ; From Table 1, Figure 2 and 3 It can be seen that the effects of pulsed electrothermal treatment on 7075 aluminum alloy components produced by friction stir additive manufacturing are mainly reflected in more complete strength recovery, better plasticity retention, more stable microstructure, smaller deformation, and significantly improved processing efficiency. Compared with the deposited state, the tensile strength of the component after pulse treatment in Example 1 increased from 302 MPa to 560 MPa, and the yield strength increased from 260 MPa to 495 MPa; at the same time, the elongation after fracture can still reach 12%. Compared with the traditional furnace-type T6, the tensile strength of Example 1 further increased from 543 MPa to 560 MPa. The yield strength increased from 470 MPa to 495 MPa, and the elongation after fracture increased from 9% to 12%, achieving higher strength while avoiding the significant decrease in plasticity of traditional T6. The pulse treatment in Example 1 effectively suppressed abnormal grain growth (AGG) and preserved the advantages of a fine-grained structure: after traditional furnace T6 treatment, the average grain size was >500 μm and AGG appeared, while after the pulse treatment in Example 1, the average grain size remained at 5~8 μm, only slightly larger than the deposited state of 3~5 μm, but still remained fine and uniform; the corresponding microstructure photographs show ( Figure 2 and 3 The microstructure treated in Example 1 exhibits a more uniform and refined grain structure, while the traditional T6 sample shows obvious coarse grains / abnormally grown areas. Figure 3 This demonstrates, from an organizational perspective, the effect of the “short-term, localized, controlled” thermal process in Example 1 on suppressing AGG, thereby achieving the preservation of fine grain strengthening; Example 1: Pulse processing can significantly improve dimensional stability and is suitable for complex thin-walled / large-sized components: Example 1 uses local scanning electric pulse processing, which significantly reduces the maximum deformation of the component from 5.2mm to 0.3mm compared with traditional furnace-type overall heating, demonstrating its advantage in shape accuracy; Example 1 shows a significant improvement in pulse post-processing efficiency and a substantial reduction in energy consumption and cycle time: the total time for traditional furnace-type T6 is about 30 hours, while the total time for pulse processing in Example 1 is about 1.5 hours, resulting in a 20-fold increase in processing efficiency; at the same time, since the energy is applied directly to the components in an electrothermal manner and can be scanned in sections, it has higher process controllability and energy-saving potential.

[0036] Comparative Example 3: The only difference between this comparative example and Comparative Example 2 is that the solution treatment in step (2) is heated to 430°C.

[0037] Example 2: This example uses 7075 aluminum alloy as the processing object; A method for controlling the microstructure and properties of aluminum alloy additive components produced by friction stir, comprising the following specific steps: (1) Using a solid-state friction stir deposition additive manufacturing equipment, 7075-T6 aluminum alloy rods with a diameter of 15mm are used as raw materials. The 7075-T6 aluminum alloy is deposited on a 7075-T6 aluminum alloy substrate by friction stir deposition to obtain an aluminum alloy additive component with an equiaxed fine grain structure. The aluminum alloy additive component has a single wall structure with dimensions of 300mm (length) × 40mm (width) × 6mm (height) (i.e., thickness t=6mm). The spindle speed of the solid-state friction stir deposition additive manufacturing equipment is 250rpm, the traverse speed of the printing tool is 100mm / min, and the single-layer deposition thickness is 1.5mm. (2) First-stage thickness adaptive stress relief: The aluminum alloy additive component is scanned pass-by-pass using an electrical pulse electrode with an electrode spacing of 20 mm at a scanning speed of 100 mm / min; based on the component thickness... t =6mm, the control system sets the low-frequency high-energy pulse parameters according to the following function, and uses the synergistic effect of electronic wind power and Joule heating to release residual stress at 150℃: The pulse frequency setting constant of the pulse current is C1 = 3000 Hz·mm, which satisfies... f 1( t ) = 3000 / 6 = 500Hz, pulse width setting coefficient k 1 = 15 μs / mm, constant t min1 =160μs, which satisfies t 1( t )=15 6 +160=250μs Effective current density J 1 Setting coefficientsa 1 = 0.5A / mm 3 ,constant J min1 = 2A / mm 2 ,satisfy J 2 (t)=0.5 6+2=5A / mm 2 The scanning speed is 300 mm / min, and the temperature of the local area in contact with the aluminum alloy additive component is 150℃ by adjusting the duty cycle of the pulse current. (3) Second stage rapid solution treatment and quenching: The area of ​​the aluminum alloy additive component after residual stress is released is locally scanned at a scanning speed of 100 mm / min. During the scanning process, a high-frequency high-energy pulsed current is applied. Utilizing the skin effect and Joule heating effect of the high-frequency high-energy pulsed current, the scanned area is rapidly heated to the solution temperature range (the peak temperature quickly reaches 430℃, about 0.90Ts) and held for a short period of 10 seconds. Subsequently, it is rapidly quenched by a water mist spray quenching device at a cooling rate greater than 100℃ / s. The parameters of the high-frequency high-energy pulsed current are controlled according to the following functional relationship: The pulse frequency setting constant for the pulse current is C2 = 15000 Hz·mm, and the exponent α is... = Version 1.0 satisfies f 2( t )=C2·t -α =15000 / 6=2500Hz; Pulse width setting coefficient k 2 = 5 μs / mm, constant t min2 =70μs, which satisfies t 1( t )= k 2 t + t min2 =5 6 + 70 = 100 μs; effective current density J 1 Setting coefficients a 1 = 0.5A / mm 3 ,constant J min1 = 2A / mm 2 ,satisfy J 2 (t)= 0.5 6+2=5A / mm 2; (4) Third stage gradient adaptive aging: A pulsed current is applied to the quenched aluminum alloy component, and the duty cycle of the pulsed current is dynamically adjusted to stabilize the aging temperature at 100℃, with a cumulative aging time of 10 min; the pulse frequency of the aging process... f 3. Pulse width τ3 and effective current density J 3 are based on thickness t A continuous functional relationship was established for adjustment to maintain a uniform precipitation driving force across cross-sections of different thicknesses, resulting in the precipitation of a diffusely distributed strengthening phase upon air cooling to room temperature; the parameters were set as follows: The pulse frequency setting constant of the pulse current is C3 = 60 Hz·mm, which satisfies... f 3( t ) = 60 / 6 = 10Hz; Pulse width setting coefficient k 1 = 10 μs / mm, constant t min1 =40μs, satisfying t 1( t )=10 6 + 40 = 100 μs; Effective current density J 1 Setting coefficients a 1 = 0.5A / mm 3 ,constant J min1 = 2A / mm 2 ,satisfy J 2 (t)= 0.5 6+2=5A / mm 2 .

[0038] Example 3: This example uses 7075 aluminum alloy as the processing object; A method for controlling the microstructure and properties of aluminum alloy additive components produced by friction stir, comprising the following specific steps: (1) Using a solid-state friction stir deposition additive manufacturing equipment, 7075-T6 aluminum alloy rods with a diameter of 15mm are used as raw materials. The 7075-T6 aluminum alloy is deposited on a 7075-T6 aluminum alloy substrate by friction stir deposition to obtain an aluminum alloy additive component with an equiaxed fine grain structure. The aluminum alloy additive component has a single wall structure with dimensions of 300mm (length) × 40mm (width) × 100mm (height) (i.e., thickness t=100mm). The spindle speed of the solid-state friction stir deposition additive manufacturing equipment is 250rpm, the traverse speed of the printing tool is 100mm / min, and the single-layer deposition thickness is 1.5mm. (2) First-stage thickness adaptive stress relief: The aluminum alloy additive component is scanned pass-by-pass using an electrical pulse electrode with an electrode spacing of 500 mm at a scanning speed of 300 mm / min; based on the component thickness... t =100mm, the control system sets the low-frequency high-energy pulse parameters according to the following function, and uses the synergistic effect of electronic wind power and Joule heating to release residual stress at 250℃: The pulse frequency setting constant of the pulse current is C1 = 1000 Hz·mm, which satisfies... f 1( t ) = 1000 / 100 = 10Hz, pulse width setting coefficient k 1 = 13 μs / mm, constant t min1 =200μs, satisfying t 1( t )=13 100 + 200 = 1500 μs; effective current density J 1 Setting coefficients a 1 = 0.5A / mm 3 ,constant J min1 = 10A / mm 2 ,satisfy J 2 (t)= 0.5 100 + 10 = 60 A / mm 2 The scanning speed is 500 mm / min, and the temperature of the local area in contact with the aluminum alloy additive component is 250℃ by adjusting the duty cycle of the pulse current. (3) Second stage rapid solution treatment and quenching: The area of ​​the aluminum alloy additive component after residual stress is released is locally scanned at a scanning speed of 500 mm / min. During the scanning process, a high-frequency high-energy pulsed current is applied. Utilizing the skin effect and Joule heating effect of the high-frequency high-energy pulsed current, the scanned area is rapidly heated to the solution temperature range (the peak temperature quickly reaches 475℃) and held for a short period of 15 seconds. Subsequently, it is rapidly quenched by a water mist spray quenching device at a cooling rate greater than 100℃ / s. The parameters of the high-frequency high-energy pulsed current are controlled according to the following functional relationship: The pulse frequency setting constant for the pulse current is C2 = 5000 Hz·mm, and the exponent α is... = Version 1.0 satisfies f 2( t )=C2·t -α =5000 / 100=50Hz; Pulse width setting coefficient k2 = 50 μs / mm, constant t min2 =900μs, which satisfies t 1( t )= k 2·t2+ t min2 =50 6 + 900 = 1200 μs; Effective current density J 2. Setting coefficients a 2 = 5.0 A / mm 3 ,constant J min2 =90A / mm 2 ,satisfy J 2( t )= a 2· t + J min2 =5.0 6 + 90 = 120 A / mm 2 ; (4) Third stage gradient adaptive aging: A pulsed current is applied to the quenched aluminum alloy component, and the duty cycle of the pulsed current is dynamically adjusted to stabilize the aging temperature at 150℃, with a cumulative aging time of 240 min; the pulse frequency of the aging process... f 3. Pulse width τ3 and effective current density J 3 are based on thickness t A continuous functional relationship was established for adjustment to maintain a uniform precipitation driving force across cross-sections of different thicknesses, resulting in the precipitation of a diffusely distributed strengthening phase upon air cooling to room temperature; the parameters were set as follows: The pulse frequency setting constant of the pulse current is C3 = 20000 Hz·mm, which satisfies... f 3( t ) = 20000 / 100 = 200Hz; Pulse width setting coefficient k 1 = 0.5 μs / mm, constant t min1 =50μs, satisfying t 1( t )=0.5 100 + 50 = 100 μs; effective current density J 1. Set coefficient a 1 = 0.5 A / mm 3 ,constant J min1 =50A / mm 2 ,satisfy J 2( t )=0.5 100 + 50 = 100 A / mm 2 .

[0039] Example 4: This example is for a 7075 aluminum alloy friction stir deposition additive component with variable cross-section characteristics (uneven wall thickness); A method for controlling the microstructure and properties of aluminum alloy additive components produced by friction stir, comprising the following specific steps: (1) Using a solid-state friction stir deposition additive manufacturing equipment, 7075-T6 aluminum alloy rods with a diameter of 15mm are used as raw materials. The 7075-T6 aluminum alloy is deposited on a 7075-T6 aluminum alloy substrate by friction stir deposition to obtain an aluminum alloy additive component with an equiaxed fine grain structure. The aluminum alloy additive component is a single-wall structure with a size of 300mm (length) × 40mm (width). The thickness varies along the additive thickness accumulation direction. The wall thickness of the thick wall region is 20mm, and the wall thickness of the thin wall region is 6mm. There is a linear transition connection region of about 30mm between the two regions. The spindle speed of the solid-state friction stir deposition additive manufacturing equipment is 250rpm, the traverse speed of the printing tool is 100mm / min, and the single-layer deposition thickness is 1.5mm. (2) First stage thickness adaptive stress relief: The aluminum alloy additive component is scanned one pass at a scanning speed of 300 mm / min using an electric pulse electrode with an electrode spacing of 40 mm; based on the variable component thickness, the control system sets the low-frequency high-energy pulse parameters according to the following function, and releases the residual stress at 220℃ by utilizing the synergistic effect of electronic wind and Joule heating: The control system based on real-time location x Get thickness t ,according to f 1( t )=2500 / t Dynamic adjustment, the pulse current and pulse frequency continuously vary between 125Hz (thick section) and 500Hz (thin section); pulse width setting coefficient. k 1 = 15 μs / mm, constant t min1 =200μs, the pulse current pulse width continuously varies between 500μs (thick area) and 275μs (thin area); effective current density J 1. Set coefficient a 1 = 1.0 A / mm 3 ,constant J min1 =10A / mm 2 The effective current density of the pulsed current is 30A / mm². 2 (Thickness) up to 15A / mm 2 (Thin areas) change continuously; (3) Second stage rapid solution treatment and quenching: The area of ​​the aluminum alloy additive component after residual stress is released is locally scanned at a scanning speed of 300 mm / min. During the scanning process, a high-frequency high-energy pulsed current is applied. Utilizing the skin effect and Joule heating effect of the high-frequency high-energy pulsed current, the scanned area is rapidly heated to the solution temperature range (the peak temperature quickly reaches 475℃) and held for a short period of 15 seconds. Subsequently, it is rapidly quenched by a water mist spray quenching device at a cooling rate greater than 100℃ / s. The parameters of the high-frequency high-energy pulsed current are controlled according to the following functional relationship: The pulse frequency setting constant for the pulse current is C2 = 6000 Hz / mm, and the exponent α is... = Version 1.0 automatically outputs data at a 20mm thick wall. f 2=300Hz, ensuring deep heat penetration; automatic output at a 5mm thin wall. f 2 =1200Hz, which concentrates the current on the surface to prevent melting; in the transition region, the frequency increases smoothly inversely with the decrease of thickness. Pulse width satisfies t 2( t )= k 2·t+ t min2 =46 t +266μs, thick-walled region t 2≈1186μs, thick-walled region t 2≈496μs, achieving linear matching of energy injection time; current density satisfies J 2( t )= a 2· t + J min2 =4 t +40A / mm 2 posterior wall area J 2=120A / mm 2 thin-walled region J 2=60A / mm 2 To compensate for volumetric heat conduction losses; (4) Third stage gradient adaptive aging: A pulsed current is applied to the quenched aluminum alloy component, and the duty cycle of the pulsed current is dynamically adjusted to stabilize the aging temperature at 120℃, with a cumulative aging time of 50 min; the pulse frequency of the aging process... f 3. Pulse width τ3 and effective current density J 3 are based on thickness t A continuous functional relationship was established for adjustment to maintain a uniform precipitation driving force across cross-sections of different thicknesses, resulting in the precipitation of a diffusely distributed strengthening phase upon air cooling to room temperature; the parameters were set as follows: The control system based on real-time locationx Get thickness t ,according to f 1( t )=2500 / t Dynamic adjustment, the pulse current and pulse frequency continuously vary between 125Hz (thick section) and 500Hz (thin section); pulse width setting coefficient. k 1 = 15 μs / mm, constant t min1 =250μs, the pulse current pulse width continuously varies between 550μs (thick area) and 325μs (thin area); effective current density J 1. Set coefficient a 1 = 1.0 A / mm 3 ,constant J min1 =15A / mm 2 The effective current density of the pulsed current is 35 A / mm². 2 (Thickness) up to 20A / mm 2 The transition between the thin and thick walls is continuous; in the transition zone between the thick and thin walls, the linear transition is completed within 1 second by using a gradual change in frequency and duty cycle to avoid transient arcs, sudden changes in contact resistance, or local temperature spikes caused by sudden changes in frequency. For complex components with non-uniform wall thickness, this embodiment proposes a dynamic scanning strategy based on a thickness function. For a wedge-shaped 7075 aluminum alloy additive component with a linear transition from 20mm to 5mm, the control system reads the position coordinates of the robotic arm. x And calculate the local thickness in real time according to the preset geometric model. t ( x In the second stage of rapid solution treatment, the output parameters of the pulse power supply respond in real time according to the following function: frequency response: f =6000 / t (Hz), as the thickness decreases from 20mm to 5mm, the frequency smoothly increases from 300Hz to 1200Hz; ensuring that the dimensionless skin depth ratio is maintained within a reasonable range of 0.2~0.4, preventing the thermal efficiency from decreasing due to excessive current transmission in thin-walled areas, while also avoiding only surface heating in thick-walled areas; as the thickness decreases, the system automatically reduces the energy input flux and duration per unit area; the dual throttling mechanism precisely offsets the accelerated temperature rise rate caused by the decrease in heat capacity in thin-walled areas, ensuring that the peak temperature is stably controlled within the solution window of 470±10℃, whether the build thickness is 20mm or 5mm; in contrast, if a fixed parameter is used to scan the transition region, it is very easy for "thermal runaway" to occur at the thin-walled end, resulting in melting and collapse, or for "underheating" to occur at the thick-walled end, resulting in residual strengthening phase; Table 2 Performance of aluminum alloy additive components in Examples 1-4 and Comparative Examples 1-3 ; From Table 2 and Figure 2 , Figure 3 It can be seen that by introducing a thickness-based... t Functional electrical pulse parameter control strategy f (t), τ(t), J (t) has significant advantages in improving the mechanical properties, dimensional accuracy and microstructure uniformity of additive components; Synergistic Enhancement of Strength and Plasticity Based on Thermal Relaxation Matching: The performance of Example 1 and Comparative Example 2 shows that Example 1 achieves a tensile strength of 560 MPa, superior to the 543 MPa of traditional T6 heat treatment (Comparative Example 2), while maintaining an elongation at break of 12% (compared to only 9% in Comparative Example 2). Traditional heat treatment (Comparative Example 2) leads to grain boundary depinning and abnormal grain growth (AGG > 500 μm) due to prolonged heat treatment, whereas Example 1, through pulse width function τ(t) = k ·t+τ min The thermal relaxation time at this thickness was precisely matched to ensure that the energy injection just meets the solid solution requirements without being excessive; at the same time, it was combined with the current density function. J (t) Compensating for volumetric heat dissipation. Millisecond-level "precise injection" completes solute re-dissolution before grain boundary depinning occurs, which not only inhibits grain coarsening (maintaining it at 5-8μm), but also retains the supersaturated solid solution through rapid water mist spraying, successfully achieving the synergistic effect of "fine grain strengthening" and "precipitation strengthening"; Deformation control and near-net-shape forming: As can be seen from the performance of Example 1 and Comparative Example 2, in terms of deformation control, Comparative Example 2 adopts an overall water quenching process, and the huge thermal stress causes the thin-walled part to produce a warping deformation of up to 5.2 mm; while Example 1 adopts a "local scanning + following spray quenching" strategy, which restricts the heat-affected zone to a very small moving window, so that the macroscopic component body is always in a low-temperature rigid state, and the final deformation is only 0.3 mm, effectively realizing low-stress "near-net-shape forming" of large thin-walled components; The influence of process parameters on performance: The performance of Examples 2 and 3 shows that Example 2 (low-temperature advantage), even at a relatively low processing temperature (430℃), benefits from the non-thermal effect of the "electron wind" of the electrical pulse, which assists in accelerating the re-dissolution of some solute atoms. The component still achieved high tensile strength (535MPa) and excellent elongation after fracture (14.5%), demonstrating the high efficiency of the process at low temperatures. However, in Example 3 (excessive energy input), when the energy input was too high, the component experienced overheating and over-aging. Data shows that its tensile strength decreased to 510MPa, and due to grain overheating and the precipitation of coarse second phases, its plasticity significantly decreased, with an elongation after fracture of 11.5%. This indicates that reasonable energy input control is crucial for performance. Dynamic balance of "heat input-heat capacity" in variable cross-section members: Example 4 demonstrates the core advantage of this method—the uniformity of microstructure and properties (tensile strength 557 MPa, elongation 13%) in complex variable cross-section members; during the transition from 20 mm to 5 mm, the control system... f (t)=C2 / t The frequency was linearly increased from 300Hz to 1200Hz; the skin effect at high frequencies prevented full current transmission at the thin-walled section (5mm), avoiding short-circuit melting or overheating collapse due to insufficient resistance; the low frequency (300Hz) ensured that the current at the thick-walled section (20mm) could diffuse towards the center through the skin depth, avoiding the undersolution phenomenon of "external heat and internal cold". Current density is based on J (t)= a ·t+ J min From 60A / mm 2 Dynamically increased to 120A / mm 2 This precisely compensates for the significant difference in heat capacity caused by the increase in thickness, ensuring that the effective energy density per unit volume remains constant throughout the transition region. This dual throttling mechanism eliminates the common problem of "thin-wall overheating and thick-wall underheating" in the heat treatment of variable cross-section components, achieving consistent performance across the entire range.

[0040] The method of this invention establishes electrical pulse parameters ( f,t,J ) and component geometric features ( t The explicit functional relationship between the two breakthroughs overcomes the three major technical bottlenecks faced by friction stir additive manufacturing components in the post-processing stage: abnormal grain growth, uneven cross-sectional performance, and uncontrolled thermal deformation.

[0041] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method of tailoring the microstructure and properties of a friction-stir-processed additive-manufactured aluminum alloy component, characterized by, The specific steps are as follows: (1) The additive raw materials are deposited on an aluminum alloy substrate by friction stir additive manufacturing to obtain an aluminum alloy additive component with an equiaxed fine grain structure; (2) First stage self-adapting stress relief treatment: using the electric pulse system equipped with thickness monitoring and position feedback, the aluminum alloy additive component is scanned row by row or layer by layer, and the real-time thickness of the scanning area is dynamically adjusted during the scanning process t The electric pulse parameters are dynamically adjusted, low-frequency high-energy pulse current is applied for stress relief treatment, and the electron wind excited by the Joule heat effect and the low-frequency high-energy pulse current is used to promote the movement and annihilation of dislocations at low temperature and release residual stress; The parameters of the low-frequency high-energy pulse current are controlled according to the following functional relationship: Pulse frequency f 1 with thickness t Negative correlation, meet the function relationship f 1(t)=C1 / t To ensure that the current penetration depth covers the cross-section of the member; Pulse width τ1 and thickness t are positively correlated, satisfying the functional relationship τ1(t)= k 1· t +τ min1 to match the thermal relaxation time under different thicknesses; Effective current density J 1 and thickness t They are positively correlated and satisfy a functional relationship. J 1(t)= a 1· t + J min1 This is to compensate for the increased volumetric heat conduction loss as the thickness increases; (3) Second stage rapid solution and quenching: The area after the residual stress of the aluminum alloy additive component is released is scanned and a high-frequency, high-energy pulse current is applied; the skin effect and Joule heating effect of the high-frequency current are used to rapidly heat the area of ​​different thicknesses to the solution temperature range and maintain a constant thermal effect depth to achieve rapid re-dissolution of solute atoms; then rapid quenching is carried out using a follow-up cooling device to form a supersaturated solid solution; The parameters of the high-frequency, high-energy pulse current are controlled according to the following functional relationship: pulse frequency f 2. Following the matching principle of skin depth and thickness, satisfying the power-law function relationship. f 2(t)=C2· t -α ; The pulse width τ2 satisfies the functional relationship τ2(t) = k 2. t +τ min2 To match the thermal relaxation time under different thicknesses; Effective current density J 2. Satisfies the functional relationship J 2(t)= a 2. t + J min2 ; (4) Third-stage gradient adaptive aging treatment: A third-stage pulse current is applied to the quenched aluminum alloy component to perform global or local scanning aging treatment; wherein, the pulse frequency of the aging treatment is... f 3. Pulse width τ3 and effective current density J 3 are based on thickness t A continuous functional relationship is established for adjustment to maintain a uniform precipitation driving force in cross-sections of different thicknesses, and the strengthening phase is precipitated in a diffuse distribution after air cooling to room temperature.

2. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: Step (1) The additive raw materials are rods, wires, powders or their waste.

3. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: In step (2), the functional relationship of the low-frequency high-energy pulse current, the constant is... C 1. The value range is 2000~5000Hz·mm; pulse frequency f The control range of 1 is 10~500Hz; coefficient k 1 is a positive number, pulse width τ The control range of 1 is 250~1500μs; coefficient a 1 is a positive number, representing the effective current density. J The control range of 1 is 5~60A / mm 2 The electrode scanning speed is 10~500mm / min. By adjusting the duty cycle, the local temperature of the area in contact between the electrode and the aluminum alloy additive component is controlled to be 150~250℃.

4. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: In step (3), the functional relationship of the high-frequency, high-energy pulse current, the constant is... C 2. The value range is 5000~15000Hz·mm; the value range of the constant α is 1.0~2.0, and the pulse frequency... f The modulation range of 2 is 50~2500Hz; pulse width τ The control range of 2 is 100~1200μs; effective current density J The control range of 2 is 5~120A / mm 2 The electrode scanning speed is 10~500 mm / min; for the transition region with gradually changing thickness, the pulse width is linearly or non-linearly smoothed according to the thickness change at the scanning position.

5. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: The peak temperature in the solution treatment temperature range of step (3) is the solidus temperature of the aluminum alloy. T The scanning speed is 90%~98% of the maximum speed; the scanning method is a pause-pulse-move step scanning or a low-speed continuous scanning with a speed of 10~300mm / min; in the transition area where the component thickness changes, the thickness data is obtained according to the real-time position coordinates, and the pulse frequency, pulse width and current density are dynamically adjusted in real time according to the preset function relationship at a refresh rate of not less than 10Hz.

6. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: In step (4), the pulse frequency of the aging process f 3 is set to 10~200Hz, and varies with thickness. t Increase and decrease, satisfying a functional relationship f 3(t) = C3 / t + f min3 Effective current density J 3. Satisfy the functional relationship J 3(t)= a 3· t + J min3 The control range is 5~100A / mm 2 The pulse width τ3 satisfies the functional relationship τ3(t) = k 3· t +τ min3 The control range is 100~800μs.

7. The method for regulating the microstructure and properties of friction stir additive aluminum alloy components according to claim 1, characterized in that: The aging temperature is controlled at 100~180℃, and the cumulative aging time is 10~240min.

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