High-strength and high-conductivity aluminum alloy powder for selective laser melting and low-residual-stress forming process of high-strength and high-conductivity aluminum alloy powder

Abstract

The invention discloses high-strength and high-conductivity aluminum alloy powder for selective laser melting and a low-residual-stress forming process of the high-strength and high-conductivity aluminum alloy powder, and belongs to the crossing field of SLM additive manufacturing and high-performance aluminum alloy materials. In order to solve the problems that in the prior art, the strong conduction contradiction is prominent, and the residual stress is high, the composition proportion is precisely designed, specifically, 4.8%-6.2% of Mn, the Sc / Zr molar ratio is 1.5: 1, 0.05%-0.12% of trace Cr and Mg-Si are precisely matched, a three-stage gas atomization preparation technology and an SLM forming scheme are combined, and a synergistic system of components, the structure, the technology and the performance is formed. The tensile strength of the obtained component is larger than or equal to 610 MPa, the electric conductivity is larger than or equal to 32.2% IACS, the residual stress is smaller than or equal to 135 MPa, the density is larger than or equal to 99.6%, the performance bottleneck of a traditional aluminum alloy is effectively broken through, the method is suitable for aerospace, electronic packaging and other high-end equipment scenes, and a reliable high-performance aluminum alloy additive manufacturing technical path is provided.

Description

Technical Field

[0001] This invention relates to the field of high-performance aluminum alloy materials technology, specifically to a high-strength, high-conductivity aluminum alloy powder adapted to the rapid solidification characteristics of laser selective melting, and a matching low residual stress forming process. Background Technology

[0002] Aluminum alloys are widely used in aerospace, electronics, and power industries due to their lightweight and ease of processing. However, they have long faced a technical bottleneck of "contradictory strength and conductivity." In existing technologies, high-strength aluminum alloys typically rely on multi-element solid solution strengthening or precipitation strengthening, which significantly hinders electron transport, leading to deterioration in conductivity. Conversely, high-conductivity aluminum alloys, due to their simple composition, often lack the strength to meet load-bearing requirements. This is especially true in laser selective melting additive manufacturing, where cooling rates can reach as high as 10⁻⁶. 6 -10 7 The K / s ratio is much higher than that of traditional casting processes, which can easily lead to the segregation of alloying elements, coarse or agglomerated strengthening phases, further exacerbating the contradiction of strong conductivity. At the same time, it will also generate high residual stress, leading to an increased risk of cracking in the formed parts.

[0003] Existing laser selective melting (LSM) aluminum alloys (such as Al-Mg-Sc-Zr alloys) are mostly designed with low Mn content, with Mn serving only as an auxiliary strengthening element, offering limited strength improvement. Furthermore, no solutions have been designed to address the potential decrease in conductivity caused by high Mn content. The addition of Sc and Zr lacks precise ratio control, resulting in Al3(Sc,Zr) phases that are mostly lamellar or needle-like, easily agglomerating at grain boundaries, affecting material toughness and strengthening effect. Simultaneously, current technologies fail to recognize the conductivity regulation role of trace amounts of Cr within the alloy matrix, using it only for surface conductivity treatment, thus failing to fundamentally solve the problem of synergistic development between high strength and high conductivity. In addition, existing LSM forming processes are mostly designed with general parameters, not deeply adapted to the compositional characteristics of aluminum alloys. This leads to difficulty in effectively controlling residual stress, insufficient density and performance stability of formed parts, and an inability to meet the synergistic requirements of high-end equipment for materials with "high strength, high conductivity, and low stress." Summary of the Invention

[0004] In view of this, the present invention proposes a high-strength and high-conductivity aluminum alloy powder for laser selective melting and its low residual stress forming process, aiming to solve the problems of prominent contradiction between high conductivity and high residual stress, and poor forming stability of aluminum alloys used in SLM in the prior art.

[0005] The technical solution of this invention is achieved as follows: This invention provides a high-strength, high-conductivity aluminum alloy powder for laser selective melting, comprising, by mass percentage: Mn 4.8-6.2%, Mg 1.2-2.0%, Si 0.6-1.0%, Sc 0.5-0.9%, Zr 0.3-0.6%, Cu 0.3-0.8%, Ti 0.08-0.15%, Cr 0.05-0.12%, Fe≤0.08%, impurities≤0.15%, with the remainder being Al; the molar ratio of Sc to Zr is 1.5:1, and the mass ratio of Mg to Si is 1.5-2.2:1.

[0006] In some embodiments, the preferred ranges of each component by mass percentage are: Mn 5.5-5.8%, Mg 1.6-1.8%, Si 0.8-0.9%, Sc 0.7-0.8%, Zr 0.4-0.5%, Cu 0.5-0.6%, Ti 0.10-0.12%, Cr 0.08-0.10%, Fe ≤0.06%, impurities ≤0.10%, and the remainder being Al.

[0007] In some embodiments, the aluminum alloy powder contains an Al3(Sc,Zr) phase, which is a spherical nano-dispersed phase with a size of 5-20 nm.

[0008] In some embodiments, the aluminum alloy powder contains a Mn-Cr composite conductive phase, which is a continuous network structure that forms conductive channels with a channel width of 50-100 nm.

[0009] In some embodiments, the aluminum alloy powder contains a Mg2Si phase, which is in the form of nanorods with a size of 30-80 nm, and forms a bi-level strengthening system with the Al3(Sc,Zr) phase.

[0010] In some embodiments, the present invention also provides a process for preparing the above-mentioned aluminum alloy powder, comprising the following steps: (1) Smelting: In a medium-frequency induction furnace, preheat pure aluminum ingots at 460℃ and then heat to 730-750℃ to melt. Add Al-Mn, Al-Cu, Al-Si, and Al-Ti master alloys in sequence and hold for 15 minutes. Heat to 750-760℃ and add Al-Sc and Al-Zr master alloys and hold for 30 minutes. Cool to 740-750℃ and add pure magnesium ingots and Al-Cr master alloys. Hold for 15 minutes and then add Al-Ti-B wires to refine the grains. Let stand for 8 minutes to remove gas. (2) Atomization powder production: A three-stage gas atomization process is adopted, with a first-stage atomization pressure of 2.5-2.8 MPa, a second-stage atomization pressure of 1.8-2.0 MPa, and a third-stage ultrasonic atomization frequency of 40 kHz, with a cooling rate ≥10. 5 K / s; (3) Sieving and packaging: Under argon protection, the powder is sieved into 15-53μm particle size, vacuum packaged, and the oxygen content of the powder is ≤300ppm.

[0011] In some embodiments, the present invention also provides a low residual stress forming process based on the above-mentioned aluminum alloy powder, comprising the following steps: (1) Pretreatment: Dry the aluminum alloy powder in vacuum at 120℃ for 2 hours, and use 5052 aluminum alloy substrate and preheat it to 380-420℃; (2) SLM forming: laser power 240-260W, scanning speed 900-1000mm / s, scanning spacing 0.07mm, layer thickness 30μm; adopting a bidirectional scanning strategy of 67° interlayer rotation + 90° cross-remelting every 5 layers, forming energy density 40-42J / mm 3 Remelting energy density 30 J / mm 3 ; (3) Post-treatment: Solution treatment at 530-550℃ for 2 hours followed by water quenching, pre-cooling at -20℃ for 1 hour, and then aging at 190-210℃ for 6 hours followed by air cooling.

[0012] In some embodiments, during the forming process, the protective atmosphere for SLM forming is argon gas with a purity of ≥99.999%, the oxygen content during forming is ≤50ppm, the water quenching cooling rate is ≥80℃ / s, and the aging temperature is below 280℃.

[0013] In some embodiments, the present invention also provides an aluminum alloy component prepared by the above forming process, which combines high strength, high conductivity and low residual stress characteristics, and is suitable for high-end equipment scenarios with stringent requirements for the comprehensive performance of materials.

[0014] The present invention has the following advantages over the prior art: This invention overcomes the traditional perception of a contradiction between strength and conductivity in aluminum alloys by precisely designing the composition and key ratios of aluminum alloy powder. Utilizing a unique microstructure formed by specific element combinations, it achieves a synergistic improvement in both strengthening effect and conductivity. Compared to existing aluminum alloy materials used in SLM (Solid Melting Machine), this invention optimizes the ratio of Sc and Zr and the synergistic effect of other elements, transforming the strengthening phase morphology from lamellar to spherical nano-dispersed state, while simultaneously constructing continuous conductive channels. This enhances both the material's strength and toughness while ensuring excellent conductivity. The accompanying preparation and forming processes are specifically adapted to the alloy composition characteristics, effectively suppressing elemental segregation and brittle phase formation during the rapid solidification process of SLM, significantly reducing residual stress and cracking risk in the formed parts, and improving material density and performance stability. The overall solution forms a synergistic optimization system of "composition-structure-process-performance," solving the technical challenge of simultaneously achieving high strength, high conductivity, and low residual stress in existing technologies. It provides a new technical path for additive manufacturing of high-performance aluminum alloy components for high-end equipment, with broad application prospects. Detailed Implementation The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1 1. Aluminum alloy powder preparation steps Step 1: Smelting preparation. Industrial pure aluminum ingots with a purity ≥ 99.7% are selected, along with Al-Mn (Mn content 20%), Al-Cu (Cu content 30%), Al-Si (Si content 25%), Al-Ti (Ti content 5%), Al-Sc (Sc content 2%), Al-Zr (Zr content 3%), and Al-Cr (Cr content 5%) master alloys. All raw materials are vacuum dried at 120℃ for 4 hours to remove surface moisture. Step 2: Preheat the medium-frequency induction furnace to 460℃, add pure aluminum ingots, raise the temperature to 730℃ to completely melt them, stir evenly, and then add Al-Mn, Al-Cu, Al-Si, and Al-Ti master alloys in sequence. Maintain the temperature at 730~750℃ and hold for 15 minutes to ensure that the master alloys are completely dissolved. Step 3: Heat the melt to 750℃, add Al-Sc and Al-Zr master alloy (Sc to Zr molar ratio 1.5:1), hold for 30 min, and stir once every 5 min (stir for 30 s each time) to ensure uniform distribution of Sc and Zr elements; Step 4: Cool the melt to 740℃, add pure magnesium ingots and Al-Cr master alloy, hold for 15 min, then add Al-Ti-B wire (1.2 mm in diameter, 0.1% of the melt mass) to refine the grains, let stand for 8 min to degas, and maintain argon protection (purity ≥99.999%) during this period to ensure that the oxygen content of the melt is ≤150ppm; Step 5: A three-stage gas atomization process is used for powder preparation. The first-stage atomization pressure is 2.5 MPa, the second-stage atomization pressure is 1.8 MPa, and the third-stage ultrasonic atomization frequency is 40 kHz. The atomization medium is argon gas (purity ≥ 99.999%), and the melt cooling rate is controlled at 1.0 × 10⁻⁶. 5 K / s; Step 6: The atomized powder is sieved under argon protection, and powder with a particle size of 15~53μm is selected and vacuum packaged (vacuum degree ≤1×10). -3 (Pa), the oxygen content of the powder is ≤300ppm, for later use.

[0016] 2. Low residual stress forming steps Step 1: Pretreatment. Place the prepared aluminum alloy powder into a vacuum oven and dry it at 120°C for 2 hours to remove adsorbed moisture. Select a 5052 aluminum alloy substrate, remove the surface oxide scale by sanding, and place it in an SLM device to preheat to 390°C and keep it at that temperature for 30 minutes. Step 2: SLM forming. The dried powder is loaded into the EOSM290 equipment hopper. The laser power is set to 245W, scanning speed to 920mm / s, scanning spacing to 0.07mm, and layer thickness to 30μm. A bidirectional scanning strategy with 67° interlayer rotation is employed, with 90° cross-remelting performed every 5 layers. The forming energy density is 40~42J / mm². 3 Remelting energy density 30 J / mm 3 During the forming process, maintain a protective atmosphere of argon (purity ≥ 99.999%) and oxygen content ≤ 50 ppm; Step 3: Post-processing. After the formed component is cooled to room temperature, it is taken out and placed in a box-type resistance furnace for solution treatment at 535℃ for 2 hours. Then, it is water quenched (cooling rate 75℃ / s) to room temperature. The solution-treated component is placed in a low-temperature chamber and pre-cooled at -20℃ for 1 hour. Finally, it is placed in a resistance furnace for aging treatment at 200℃ for 6 hours and air-cooled to room temperature to obtain the final aluminum alloy component.

[0017] Example 2 1. Aluminum alloy powder preparation steps Step 1: Smelting preparation. Industrial pure aluminum ingots with a purity ≥ 99.7% are selected, along with Al-Mn (Mn content 20%), Al-Cu (Cu content 30%), Al-Si (Si content 25%), Al-Ti (Ti content 5%), Al-Sc (Sc content 2%), Al-Zr (Zr content 3%), and Al-Cr (Cr content 5%) master alloys. All raw materials are vacuum dried at 120℃ for 4 hours to remove surface moisture. Step 2: Preheat the medium-frequency induction furnace to 460℃, add pure aluminum ingots, raise the temperature to 740℃ to completely melt them, stir evenly, and then add Al-Mn, Al-Cu, Al-Si, and Al-Ti master alloys in sequence. Maintain the temperature at 730~750℃ and hold for 15 minutes to ensure that the master alloys are completely dissolved. Step 3: Heat the melt to 760℃, add Al-Sc and Al-Zr master alloy (Sc to Zr molar ratio 1.5:1), hold for 30 min, and stir once every 5 min (stir for 30 s each time) to ensure uniform distribution of Sc and Zr elements; Step 4: Cool the melt to 750℃, add pure magnesium ingots and Al-Cr master alloy, hold for 15 minutes, then add Al-Ti-B wire (1.2 mm in diameter, 0.1% of the melt mass) to refine the grains, let stand for 8 minutes to degas, and maintain argon protection (purity ≥99.999%) during this period to ensure that the oxygen content of the melt is ≤150ppm; Step 5: A three-stage gas atomization process is used for powder preparation. The first-stage atomization pressure is 2.6 MPa, the second-stage atomization pressure is 1.9 MPa, and the third-stage ultrasonic atomization frequency is 40 kHz. The atomization medium is argon gas (purity ≥ 99.999%), and the melt cooling rate is controlled at 1.2 × 10⁻⁶. 5 K / s; Step 6: The atomized powder is sieved under argon protection, and powder with a particle size of 15~53μm is selected and vacuum packaged (vacuum degree ≤1×10). -3 (Pa), the oxygen content of the powder is ≤300ppm, for later use.

[0018] 2. Low residual stress forming steps Step 1: Pretreatment: Place the prepared aluminum alloy powder into a vacuum oven and vacuum dry at 120℃ for 2 hours to remove adsorbed moisture; Select a 5052 aluminum alloy substrate, remove the surface oxide scale by sanding with sandpaper, and place it in an SLM device to preheat to 400℃ and keep it at that temperature for 30 minutes. Step 2: SLM forming. The dried powder is loaded into the EOSM290 equipment hopper. The laser power is set to 250W, scanning speed to 950mm / s, scanning spacing to 0.07mm, and layer thickness to 30μm. A bidirectional scanning strategy with 67° interlayer rotation is employed, with 90° cross-remelting performed every 5 layers. The forming energy density is 40~42J / mm². 3 Remelting energy density 30 J / mm 3 During the forming process, maintain a protective atmosphere of argon (purity ≥ 99.999%) and oxygen content ≤ 50 ppm; Step 3: Post-processing. After the formed component is cooled to room temperature, it is taken out and placed in a box-type resistance furnace for solution treatment. It is held at 540℃ for 2 hours, and then water-quenched (cooling rate 80℃ / s) to room temperature. The solution-treated component is placed in a low-temperature chamber and pre-cooled at -20℃ for 1 hour. Finally, it is placed in a resistance furnace for aging treatment, held at 200℃ for 6 hours, and air-cooled to room temperature to obtain the final aluminum alloy component.

[0019] Example 3 1. Aluminum alloy powder preparation steps The preparation steps of the aluminum alloy powder are completely consistent with those in Example 2.

[0020] 2. Low residual stress forming steps Step 1: Pretreatment: Place the prepared aluminum alloy powder into a vacuum oven and vacuum dry at 120℃ for 2 hours to remove adsorbed moisture; Select a 5052 aluminum alloy substrate, remove the surface oxide scale by sanding with sandpaper, and place it in an SLM device to preheat to 410℃ and keep it at that temperature for 30 minutes. Step 2: SLM forming. The dried powder is loaded into the EOSM290 equipment hopper. The laser power is set to 255W, scanning speed to 980mm / s, scanning spacing to 0.07mm, and layer thickness to 30μm. A bidirectional scanning strategy with 67° interlayer rotation is employed, with 90° cross-remelting performed every 5 layers. The forming energy density is 40~42J / mm². 3 Remelting energy density 30 J / mm 3 During the forming process, maintain a protective atmosphere of argon (purity ≥ 99.999%) and oxygen content ≤ 50 ppm; Step 3: Post-processing. After the formed component is cooled to room temperature, it is taken out and placed in a box-type resistance furnace for solution treatment. It is held at 540℃ for 2 hours, and then water quenched (cooling rate 85℃ / s) to room temperature. The solution-treated component is placed in a low-temperature chamber and pre-cooled at -20℃ for 1 hour. Finally, it is placed in a resistance furnace for aging treatment, held at 200℃ for 6 hours, and air-cooled to room temperature to obtain the final aluminum alloy component.

[0021] Comparative Example 1 Except for step 3, where the amount of Al-Mn master alloy added is adjusted to make the Mn content 0.8%, the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0022] Comparative Example 2 Except for step 4, in which Al-Cr master alloy is not added, the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0023] Comparative Example 3 Except for step 3, where the Al-Sc and Al-Zr master alloy additions are adjusted to 0.5% Sc and 0.5% Zr (molar ratio 1:1), the remaining aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0024] Comparative Example 4 Except for step 2, where the Al-Mg and Al-Si master alloy additions are adjusted to 2.5% Mg and 0.5% Si (mass ratio 5:1), the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0025] Comparative Example 5 Except for the use of industrial pure aluminum ingots with an Fe content of 0.12% in step 1 (the Fe content of other raw materials is kept unchanged), the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0026] Comparative Example 6 Except for adjusting the substrate preheating temperature to 280°C in forming step 1, the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0027] Comparative Example 7 Except for step 5 of the powder preparation process, which uses a single high-pressure gas atomization process (pressure 2.6MPa, no secondary atomization + ultrasonic atomization), the other aluminum alloy powder preparation steps and low residual stress forming steps are completely consistent with those in Example 2.

[0028] Comparative Example 8 Except for the post-treatment in forming step 3, which was adjusted to "solution at 530℃ for 2 hours + water quenching (cooling rate 80℃ / s) + aging at 180℃ for 6 hours" (without -20℃ pre-cooling), the other aluminum alloy powder preparation steps and low residual stress forming steps were completely consistent with those in Example 2.

[0029] Performance verification 1. Sample preparation The aluminum alloy components prepared in each embodiment and comparative example were processed into standard specimens according to the corresponding testing standards: the tensile test used dumbbell-shaped specimens (gauge length diameter 5mm, length 25mm) as specified in GB / T228.1-2021; the residual stress test used rectangular specimens (dimensions 50mm×50mm×5mm) as specified in GB / T7704-2017; the density and cracking rate test used cubic specimens (dimensions 10mm×10mm×10mm) as specified in GB / T23561-2009; the microstructure analysis specimens were cut by wire cutting (dimensions 5mm×5mm×1mm), and after grinding and polishing, they were ion-thinned to a thickness ≤100nm.

[0030] 2. Tensile property test The tensile specimens were mounted on an Instron 5982 universal testing machine. The ambient temperature was set to 25±2℃, and the loading rate was 2 mm / min until the specimens fractured. The tensile strength, yield strength (Rp0.2), and elongation (A50) were recorded. Three parallel specimens were tested for each group, and the average value was taken and the error was calculated.

[0031] 3. Conductivity test The gauge length of the tensile specimens was tested using a SigmaTest 2.069 eddy current conductivity meter at room temperature (25±2℃). Three different test points were selected, and each test point was tested three times. The average value was taken and the error was calculated. The test standard followed GB / T32791-2016.

[0032] 4. Residual stress test Using a Bruker D8 Discover X-ray diffractometer, the sin ray diffractometer was used according to the specifications in GB / T7704-2017. 2 The ψ method involves selecting three different regions on the sample surface for testing, with diffraction angles ranging from 30° to 90° and a step size of 0.02°. The average value is taken and the error is calculated.

[0033] 5. Density and crack rate test Density was determined using the Archimedes displacement method with a Mettler Toledo ME204E electronic balance (accuracy 0.1 mg). Each sample was tested three times, and the average value was taken and the error was calculated. Crack rate was determined using a Leica DM4M metallurgical microscope. Five different fields of view (magnification 200x) were observed on the sample, and the area ratio of the cracked region was statistically analyzed, the average value was taken, and the error was calculated. The testing standard followed GB / T23561-2009.

[0034] 6. Microstructure Analysis The morphology, size, and distribution of the Al3(Sc,Zr) phase, Mn-Cr composite conductive phase, and Mg2Si phase were observed using a JEM-2100F transmission electron microscope (accelerating voltage 200kV). Five different observation areas were selected for each sample, and the size of at least 50 phase particles was measured. The mean value and sphericity (sphericity = 4π × cross-sectional area / perimeter) were calculated. 2 Phase analysis was performed using a Bruker D8 Advance X-ray diffractometer with a diffraction angle range of 20° to 80° and a step size of 0.02° to verify the presence of the Mn-Cr composite conductive phase and the Fe-Al-Mn brittle phase. The testing standards followed GB / T30986-2014.

[0035] Verification results Example Performance Verification Results Table

[0036] Comparative Performance Verification Results Table

[0037] The above experimental results demonstrate that the embodiments of the present invention, through precise design of the aluminum alloy composition ratio (high Mn content, Sc / Zr molar ratio of 1.5:1, trace amounts of Cr and precise Mg-Si ratio) and a specially adapted preparation and SLM forming process, successfully achieved a synergistic effect of tensile strength, electrical conductivity, and low residual stress. The formed parts exhibit excellent comprehensive performance and strong stability. In contrast, the comparative examples, due to the absence or substitution of the core technical features of the present invention, all showed significant performance degradation: the low Mn design led to abnormal strengthening phase morphology and a significant decrease in strength; the lack of Cr addition could not overcome the contradiction between strong conductivity and low strength; the disordered Sc / Zr and Mg-Si ratio caused a deterioration in strengthening effect and toughness; and conventional SLM processes and post-treatments resulted in a surge in residual stress and an increase in forming defects. It is evident that the composition design and process parameters of this invention are not a simple combination or conventional optimization of existing technologies, but rather form an organic synergistic system of "composition-structure-process-performance". The resulting comprehensive performance improvement cannot be replicated by a single technical feature or combination of existing technologies, fully demonstrating the outstanding substantive features and significant progress of this invention, and providing a reliable technical path for additive manufacturing of high-performance aluminum alloy components for high-end equipment.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength, high-conductivity aluminum alloy powder for laser selective melting, characterized in that, By mass percentage, it includes: Mn 4.8-6.2%, Mg 1.2-2.0%, Si 0.6-1.0%, Sc 0.5-0.9%, Zr 0.3-0.6%, Cu 0.3-0.8%, Ti 0.08-0.15%, Cr 0.05-0.12%, Fe ≤0.08%, impurities ≤0.15%, and the remainder is Al; the molar ratio of Sc to Zr is 1.5:1, and the mass ratio of Mg to Si is 1.5-2.2:

1.

2. The aluminum alloy powder according to claim 1, characterized in that, By mass percentage, it includes: Mn 5.5-5.8%, Mg 1.6-1.8%, Si 0.8-0.9%, Sc 0.7-0.8%, Zr 0.4-0.5%, Cu 0.5-0.6%, Ti 0.10-0.12%, Cr 0.08-0.10%, Fe ≤0.06%, impurities ≤0.10%, and the remainder is Al.

3. The aluminum alloy powder according to claim 1 or 2, characterized in that, The aluminum alloy powder contains an Al3(Sc,Zr) phase, which is a spherical nano-dispersed phase with a size of 5-20 nm.

4. The aluminum alloy powder according to claim 1 or 2, characterized in that, The aluminum alloy powder contains a Mn-Cr composite conductive phase, which is a continuous network structure that forms conductive channels with a channel width of 50-100 nm.

5. The aluminum alloy powder according to claim 1 or 2, characterized in that, The aluminum alloy powder contains a Mg2Si phase, which is in the form of nanorods with a size of 30-80 nm, and forms a bi-level strengthening system with the Al3(Sc,Zr) phase.

6. A process for preparing aluminum alloy powder as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Smelting: In a medium-frequency induction furnace, preheat pure aluminum ingots at 460℃ and then heat to 730-750℃ to melt. Add Al-Mn, Al-Cu, Al-Si, and Al-Ti master alloys in sequence and hold for 15 minutes. Heat to 750-760℃ and add Al-Sc and Al-Zr master alloys and hold for 30 minutes. Cool to 740-750℃ and add pure magnesium ingots and Al-Cr master alloys. Hold for 15 minutes and then add Al-Ti-B wires to refine the grains. Let stand for 8 minutes to remove gas. (2) Atomization powder production: A three-stage gas atomization process is adopted, with a first-stage atomization pressure of 2.5-2.8 MPa, a second-stage atomization pressure of 1.8-2.0 MPa, and a third-stage ultrasonic atomization frequency of 40 kHz, with a cooling rate ≥10. 5 K / s; (3) Sieving and packaging: Under argon protection, the powder is sieved into 15-53μm particle size, vacuum packaged, and the oxygen content of the powder is ≤300ppm.

7. A low residual stress forming process based on the aluminum alloy powder according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Pretreatment: Dry the aluminum alloy powder in vacuum at 120℃ for 2 hours, and select 5052 aluminum alloy substrate and preheat it to 380-420℃; (2) SLM forming: laser power 240-260W, scanning speed 900-1000mm / s, scanning spacing 0.07mm, layer thickness 30μm; adopting a bidirectional scanning strategy of 67° interlayer rotation + 90° cross-remelting every 5 layers, forming energy density 40-42J / mm 3 Remelting energy density 30 J / mm 3 ; (3) Post-treatment: after solution treatment at 530-550℃ for 2 hours, water quenching, pre-cooling at -20℃ for 1 hour, and then aging at 190-210℃ for 6 hours and air cooling.

8. The forming process according to claim 7, characterized in that, In step (2), the protective atmosphere is argon with a purity of ≥99.999%, and the oxygen content during the forming process is ≤50ppm; in step (3), the water quenching cooling rate is ≥80℃ / s, and the aging temperature is below 280℃.

9. An aluminum alloy component prepared by the forming process described in claim 7 or 8, characterized in that, The component has a tensile strength ≥600MPa, a yield strength ≥490MPa, an elongation ≥8%, an electrical conductivity ≥28%IACS, a residual stress ≤140MPa, a density ≥99.4%, and a cracking rate of the molded part ≤8%.

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