A high-strength aluminum alloy material and its preparation method

Abstract

The present invention discloses a high-strength aluminum alloy material and a preparation method thereof. First, aluminum alloy powder is prepared by a water atomization method from specific proportions of Cu, Mg, Cr, Si, Mn, Sc, Zr, Mo, Ce, Yb, Al, etc. Then, the aluminum alloy powder is mixed with BW2 (tungsten boride), VB2 (vanadium diboride), and polyacrylonitrile to obtain a mixed powder, which is 3D printed using an SLM metal printer and then heat-treated to obtain the product. The aluminum alloy material of the present invention is obtained through 3D printing technology, has high strength, and meets the high-end quality requirements in fields such as aerospace.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy preparation, and particularly relates to a high-strength aluminum alloy material and a preparation method thereof. Background Art

[0002] 3D printing technology, also known as additive manufacturing (AM), generally works as follows: using a digital model file as an instruction, a digital technology material printer as a device, and metal or plastic and other bondable powders as materials, and obtaining a part product quickly by means of layer-by-layer printing. 3D printing is a process of stacking materials layer by layer to manufacture an object, rather than the traditional subtractive manufacturing method. 3D printing does not require a raw blank and a mold, and the design is more flexible.

[0003] The currently relatively mature 3D printing method, selective laser melting technology, i.e., SLM technology, works in the following way: using a precisely focused laser spot to quickly melt layer upon layer of pre-laid metal powder, and directly obtaining part products of any shape. Steel, titanium alloy, and aluminum alloy are relatively common metal bondable powders. Among them, aluminum alloy has the advantages of low density, high specific strength, good toughness, and corrosion resistance, and is an indispensable important structural material in the aerospace, transportation, and machinery manufacturing industries. Therefore, obtaining high-strength aluminum alloy materials through 3D printing has broad application prospects.

[0004] Compared with other metal materials such as stainless steel and titanium alloy, aluminum alloy has the advantages of high thermal conductivity and good formability. However, aluminum alloy has a high reflectivity to laser, a low absorption rate to laser, is easy to oxidize, and has a high thermal conductivity. During the 3D printing process, phenomena such as cracking, warping, deformation, and balling often occur, and there are problems such as low density, embrittlement, warping, and cracking in the printed components. It is one of the most difficult materials to print in 3D printing technology, and the final products often have insufficient strength and cannot meet the high-end quality requirements in fields such as aerospace. Therefore, developing aluminum alloy materials suitable for 3D printing technology is of great significance.

[0005] Patent CN110423923B discloses an aluminum alloy suitable for 3D printing. Compared with the AlSi10Mg alloy, the increase in the content of Mg element and the introduction of trace elements of Sc and Zr in the alloy of the present invention have increased the yield strength of the patented alloy. The content of Si element in the patented alloy is not far from the eutectic composition, and it has good process characteristics during the 3D printing process, and the cracking tendency during the printing process is relatively low. Compared with the AlSi10Mg alloy, the introduction of trace elements of Sc and Zr in the patented alloy can significantly improve the anisotropy of the alloy. However, the tensile strength of the aluminum alloy material obtained by 3D printing recorded in this patent is lower than 500 MPa, the yield strength is lower than 300 MPa, and the elongation after fracture is not higher than 8.0%, which still cannot meet the high-end quality requirements in fields such as aerospace. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a high-strength aluminum alloy material and its preparation method, which are obtained by 3D printing technology, have high strength, and meet the high-end quality requirements in fields such as aerospace.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A preparation method of a high-strength aluminum alloy material, first prepare aluminum alloy powder by water atomization method with the following components in mass percentage: Cu 4.1 - 4.5%, Mg 2.8 - 3.1%, Cr 2.5 - 2.8%, Si 1.2 - 1.5%, Mn 1.0 - 1.2%, Sc 0.3 - 0.5%, Zr 0.1 - 0.2%, Mo 0.08 - 0.1%, Ce 0.05 - 0.07%, Yb 0.05 - 0.07%, and the balance is Al; then mix the aluminum alloy powder with BW2 (tungsten boride), VB2 (vanadium diboride), and polyacrylonitrile to obtain a mixed powder, and perform 3D printing using an SLM metal printer and heat treatment to obtain the aluminum alloy material.

[0009] Preferably, the aluminum alloy powder is prepared by the following method: mix the components in the formula amount and heat to 1000 - 1100 °C, keep warm for 50 - 60 minutes to obtain a molten liquid; water atomize the molten liquid and dry it to obtain the aluminum alloy powder.

[0010] More preferably, water atomization is carried out using a citric acid - sodium citrate buffer solution, and the water atomization conditions are as follows: the diameter of the molten liquid flow is 25 - 30 mm, the temperature of the citric acid - sodium citrate buffer solution is 30 - 40 °C, the pressure is 90 - 100 MPa, the flow rate is 180 - 190 m 3 / h, and the spraying angle is 20 - 23°.

[0011] More preferably, the concentration of the citric acid - sodium citrate buffer solution is 0.1 mol / L and the pH = 4.4.

[0012] Preferably, the mass ratio of the aluminum alloy powder, BW2, VB2, and polyacrylonitrile is 1:0.1 - 0.2:0.1 - 0.2:0.1 - 0.2.

[0013] Preferably, the particle sizes of BW2 and VB2 are 1500 - 2000 mesh.

[0014] Preferably, the mixed powder is prepared by the following method: First, ultrasonically disperse the aluminum alloy powder in an aqueous solution of sodium dodecylbenzenesulfonate to obtain an aluminum alloy dispersion; then ultrasonically disperse BW2 and VB2 in deionized water to obtain a suspension; then add the suspension and the polyacrylonitrile solution to the aluminum alloy dispersion, stir well, filter to obtain the solid, and dry it to obtain the product.

[0015] More preferably, the dosage ratio of the aluminum alloy powder to the aqueous solution of sodium dodecylbenzenesulfonate is 1 g:3 - 4 mL, and the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 1 - 2%; the dosage ratio of BW2, VB2, and deionized water is 0.1 - 0.2 g:0.1 - 0.2 g:0.4 - 0.5 mL; the dosage of the polyacrylonitrile solution is 1 / 3 - 1 / 2 of the volume of the aluminum alloy dispersion, and the polyacrylonitrile solution is obtained by dissolving polyacrylonitrile in 5 - 6 times its weight of dimethyl sulfoxide.

[0016] More preferably, the process conditions for sufficient stirring are: stirring at 400 - 500 r / min for 3 - 4 hours.

[0017] Preferably, the specific parameters for 3D printing using an SLM metal printer are as follows: laser power 300 - 350 W, laser scanning rate 800 - 900 mm / s, laser scanning spacing 80 - 90 μm, the forming thickness of each layer of the mixed powder is 30 - 40 μm, and the interlayer rotation angle is 60 - 62°.

[0018] Preferably, the substrate of the SLM metal printer is preheated to 150 - 160 °C before use.

[0019] Preferably, the specific process of heat treatment is as follows:

[0020] (a) Heat up to 170 - 180 °C at a rate of 8 - 10 °C / min and hold for 2 - 3 hours;

[0021] (b) Cool down to - 30 - 40 °C at a rate of 15 - 18 °C / min and hold for 3 - 4 hours;

[0022] (c) Transfer to a spark plasma sintering furnace for heat preservation, and the pulsed current density is 250 - 280 A / cm 2, the temperature is 180 - 200 °C, the heating rate is 45 - 50 °C / min, and the heat preservation time is 40 - 50 minutes;

[0023] (d) Heat up to 280 - 300 °C at a rate of 25 - 30 °C / min and keep warm for 1 - 2 hours;

[0024] (e) Naturally cool to room temperature.

[0025] A high-strength aluminum alloy material is obtained by the foregoing preparation method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] In the present invention, aluminum alloy powder is first prepared by water atomization from specific proportions of Cu, Mg, Cr, Si, Mn, Sc, Zr, Mo, Ce, Yb, Al, etc.; then the aluminum alloy powder is mixed with BW2 (tungsten boride), VB2 (vanadium boride), and polyacrylonitrile to obtain a mixed powder, which is 3D printed using an SLM metal printer and heat-treated to obtain a high-strength aluminum alloy material. The aluminum alloy material of the present invention is obtained by 3D printing technology, has high strength, and meets the high-end quality requirements in fields such as aerospace.

[0028] The applicant screened and adjusted the composition of the aluminum alloy powder to ensure the basic strength requirements of the aluminum alloy material. The aluminum alloy powder is prepared by water atomization and is suitable for use in SLM technology.

[0029] The present invention further introduces tungsten boride and vanadium boride to further improve the strength of the aluminum alloy. Polyacrylonitrile forms carbon fibers during subsequent processing, which helps to further improve the strength of the aluminum alloy.

[0030] After 3D printing using an SLM metal printer, heat treatment is carried out, including heating, cooling, and reheating, which helps to optimize the microstructure of the aluminum alloy material and improve the strength of the aluminum alloy. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than 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 work fall within the scope of protection of the present invention.

[0032] Unless otherwise specified, all products in the present invention are purchased through market channels.

[0033] The polyacrylonitrile in the examples and comparative examples has a weight average molecular weight of 100,000 and is purchased from Shenzhen Dansheng Plastic Co., Ltd.

[0034] Example 1

[0035] A preparation method of a high-strength aluminum alloy material is as follows:

[0036] S1. First, prepare aluminum alloy powder by water atomization method with the following components in mass percentage: Cu 4.1%, Mg 2.8%, Cr 2.5%, Si 1.2%, Mn 1.0%, Sc 0.3%, Zr 0.1%, Mo 0.08%, Ce 0.05%, Yb 0.05%, and the balance is Al;

[0037] Specifically, mix the components in the formula amount, heat to 1000 °C, and keep warm for 50 minutes to obtain a molten liquid; use a citric acid - sodium citrate buffer solution (0.1 mol / L, pH = 4.4) to atomize the molten liquid with water, and dry it to obtain the aluminum alloy powder;

[0038] The water atomization conditions are as follows: the diameter of the molten liquid flow is 25 mm, the temperature of the citric acid - sodium citrate buffer solution is 30 °C, the pressure is 90 MPa, the flow rate is 180 m 3 / h, and the spraying angle is 20°;

[0039] S2. Then, mix the aluminum alloy powder with BW2 (tungsten diboride), VB2 (vanadium diboride), and polyacrylonitrile to obtain a mixed powder;

[0040] Specifically, first ultrasonically disperse 1 kg of aluminum alloy powder in 3 L of sodium dodecylbenzenesulfonate aqueous solution (mass concentration 1%) to obtain an aluminum alloy dispersion; then ultrasonically disperse 0.1 kg of BW2 and 0.1 kg of VB2 in 0.4 L of deionized water to obtain a suspension; then add the suspension and the polyacrylonitrile solution to the aluminum alloy dispersion, stir well (stir at 400 r / min for 3 hours), filter to obtain the solid, and dry it to obtain; the dosage of the polyacrylonitrile solution is 1 / 3 of the volume of the aluminum alloy dispersion, and the polyacrylonitrile solution is obtained by dissolving 0.1 kg of polyacrylonitrile in 5 times its weight of dimethyl sulfoxide; the particle size of BW2 and VB2 is 1500 mesh;

[0041] S3. Use an SLM metal 3D printer for 3D printing;

[0042] The specific parameters are as follows: laser power 300 W, laser scanning rate 800 mm / s, laser scanning spacing 80 μm, the forming thickness of each layer of mixed powder is 30 μm, and the interlayer rotation angle is 60°;

[0043] The substrate of the SLM metal 3D printer is preheated to 150 °C before use;

[0044] The printing atmosphere uses argon, and the printing size is 50 mm × 50 mm × 50 mm;

[0045] S4. Heat treatment;

[0046] The specific process is as follows:

[0047] (a) Heat up to 170 °C at a rate of 8 °C / min and hold for 2 hours;

[0048] (b) Cool down to -30 °C at a rate of 15 °C / min and hold for 3 hours;

[0049] (c) Transfer to a spark plasma sintering furnace for heat preservation, with a pulsed current density of 250 A / cm 2 , a temperature of 180 °C, a heating rate of 45 °C / min, and a holding time of 40 minutes;

[0050] (d) Heat up to 280 °C at a rate of 25 °C / min and hold for 1 hour;

[0051] (e) Naturally cool to room temperature.

[0052] Example 2

[0053] A preparation method of a high-strength aluminum alloy material, the specific steps are as follows:

[0054] S1. First, prepare aluminum alloy powder by water atomization method with the following components in mass percentage: Cu 4.5%, Mg 3.1%, Cr 2.8%, Si 1.5%, Mn 1.2%, Sc 0.5%, Zr 0.2%, Mo 0.1%, Ce 0.07%, Yb 0.07%, and the balance is Al;

[0055] Specifically, mix the components in the formula amount, heat to 1100 °C, and hold for 60 minutes to obtain a molten liquid; atomize the molten liquid with a citric acid - sodium citrate buffer solution (0.1 mol / L, pH = 4.4) by water atomization, and dry to obtain the aluminum alloy powder;

[0056] The water atomization conditions are as follows: the molten liquid flow diameter is 30 mm, the temperature of the citric acid - sodium citrate buffer solution is 40 °C, the pressure is 100 MPa, the flow rate is 190 m 3 / h, and the spraying angle is 23°;

[0057] S2. Then mix the aluminum alloy powder with BW2 (tungsten diboride), VB2 (vanadium diboride), and polyacrylonitrile to obtain a mixed powder;

[0058] Specifically, 1 kg of aluminum alloy powder is first ultrasonically dispersed in 4 L of sodium dodecylbenzene sulfonate aqueous solution (mass concentration 2%) to obtain an aluminum alloy dispersion; 0.2 kg of BW2 and 0.2 kg of VB2 are ultrasonically dispersed in 0.5 L of deionized water to obtain a suspension; the suspension and polyacrylonitrile solution are then added to the aluminum alloy dispersion, fully stirred (stirred at 500 r / min for 4 hours), the solid is filtered out, and dried to obtain the aluminum alloy dispersion; the amount of the polyacrylonitrile solution used is 1 / 2 of the volume of the aluminum alloy dispersion, and the polyacrylonitrile solution is obtained by dissolving 0.2 kg of polyacrylonitrile in dimethyl sulfoxide (6 times its weight); the particle size of BW2 and VB2 is 2000 mesh;

[0059] S3. 3D printing using SLM metal printer;

[0060] The specific parameters are as follows: laser power 350W, laser scanning rate 900mm / s, laser scanning spacing 90μm, the thickness of each layer of mixed powder is 40μm, and the inter-layer rotation angle is 62°;

[0061] The substrate of the SLM metal printer is preheated to 160°C before use;

[0062] The printing atmosphere uses argon gas, and the printing size is 50mm×50mm×50mm;

[0063] S4. Heat treatment;

[0064] The specific process is as follows:

[0065] (a) Raise the temperature to 180°C at 10°C / min and keep at this temperature for 3 hours;

[0066] (b) cooling to -40°C at 18°C / min and keeping warm for 4 hours;

[0067] (c) Transferred to a spark plasma sintering furnace for heat preservation, with a pulse current density of 280 A / cm 2 , temperature is 200℃, heating rate is 50℃ / min, holding time is 50 minutes;

[0068] (d) heating to 300°C at 30°C / min and keeping at this temperature for 2 hours;

[0069] (e) Cool naturally to room temperature.

[0070] Example 3

[0071] A method for preparing a high-strength aluminum alloy material, the specific steps are as follows:

[0072] S1. First, prepare aluminum alloy powder by water atomization method with the following components in mass percentage: Cu 4.3%, Mg 3%, Cr 2.7%, Si 1.3%, Mn 1.1%, Sc 0.4%, Zr 0.15%, Mo 0.09%, Ce 0.06%, Yb 0.06%, and the balance is Al;

[0073] Specifically, mix the components in the formula amount and heat them to 1050 °C, keep warm for 55 minutes to obtain a molten liquid; use a citric acid - sodium citrate buffer solution (0.1 mol / L, pH = 4.4) to atomize the molten liquid with water, and dry it to obtain the aluminum alloy powder;

[0074] The water atomization conditions are as follows: the diameter of the molten liquid flow is 28 mm, the temperature of the citric acid - sodium citrate buffer solution is 35 °C, the pressure is 95 MPa, the flow rate is 185 m 3 / h, and the spraying angle is 22°;

[0075] S2. Then, mix the aluminum alloy powder with BW2 (tungsten diboride), VB2 (vanadium diboride), and polyacrylonitrile to obtain a mixed powder;

[0076] Specifically, first ultrasonically disperse 1 kg of aluminum alloy powder in 3.5 L of sodium dodecylbenzenesulfonate aqueous solution (mass concentration 1.5%) to obtain an aluminum alloy dispersion; then ultrasonically disperse 0.15 kg of BW2 and 0.15 kg of VB2 in 0.45 L of deionized water to obtain a suspension; then add the suspension and the polyacrylonitrile solution to the aluminum alloy dispersion, stir well (stir at 500 r / min for 3 hours), filter to obtain the solid, and dry it to obtain; the dosage of the polyacrylonitrile solution is 1 / 2 of the volume of the aluminum alloy dispersion, and the polyacrylonitrile solution is obtained by dissolving 0.15 kg of polyacrylonitrile in 5 times its weight of dimethyl sulfoxide; the particle size of BW2 and VB2 is 2000 mesh;

[0077] S3. Use an SLM metal 3D printer for 3D printing;

[0078] The specific parameters are as follows: laser power 330 W, laser scanning rate 850 mm / s, laser scanning spacing 85 μm, the forming thickness of each layer of mixed powder is 35 μm, and the interlayer rotation angle is 61°;

[0079] The substrate of the SLM metal 3D printer is preheated to 155 °C before use;

[0080] The printing atmosphere uses argon, and the printing size is 50 mm × 50 mm × 50 mm;

[0081] S4. Heat treatment;

[0082] The specific process is as follows:

[0083] (a) Heat to 175°C at a rate of 9°C / min and hold for 2 hours;

[0084] (b) Cool to -35°C at a rate of 16°C / min and hold for 3 hours;

[0085] (c) Transfer to a spark plasma sintering furnace for holding, with a pulsed current density of 260 A / cm 2 , a temperature of 190°C, a heating rate of 48°C / min, and a holding time of 45 minutes;

[0086] (d) Heat to 290°C at a rate of 28°C / min and hold for 1.5 hours;

[0087] (e) Cool naturally to room temperature.

[0088] Comparative Example 1

[0089] A method for preparing an aluminum alloy material, the specific steps are as follows:

[0090] S1. First, prepare aluminum alloy powder by water atomization method from the following components in mass percentages: Cu 4.1%, Mg 2.8%, Cr 2.5%, Si 1.2%, Mn 1.0%, Sc 0.3%, Zr 0.1%, Mo 0.08%, Ce 0.05%, Yb 0.05%, and the balance is Al;

[0091] Specifically, mix the components in the formula amounts, heat to 1000°C, and hold for 50 minutes to obtain a molten liquid; atomize the molten liquid with a citric acid - sodium citrate buffer solution (0.1 mol / L, pH = 4.4) by water, and dry to obtain the aluminum alloy powder;

[0092] The water atomization conditions are as follows: the molten liquid flow diameter is 25 mm, the temperature of the citric acid - sodium citrate buffer solution is 30°C, the pressure is 90 MPa, the flow rate is 180 m 3 / h, and the spraying angle is 20°;

[0093] S2. Then, mix the aluminum alloy powder with BW2 (tungsten boride) and polyacrylonitrile to obtain a mixed powder;

[0094] Specifically, first ultrasonically disperse 1 kg of aluminum alloy powder in 3 L of sodium dodecylbenzenesulfonate aqueous solution (mass concentration 1%) to obtain an aluminum alloy dispersion; then ultrasonically disperse 0.1 kg of BW2 in 0.4 L of deionized water to obtain a suspension; then add the suspension and the polyacrylonitrile solution to the aluminum alloy dispersion, stir well (stir at 400 r / min for 3 hours), filter to obtain the solid, and dry to obtain; the amount of the polyacrylonitrile solution is 1 / 3 of the volume of the aluminum alloy dispersion, and the polyacrylonitrile solution is obtained by dissolving 0.1 kg of polyacrylonitrile in 5 times its weight of dimethyl sulfoxide; the particle size of BW2 is 1500 mesh;

[0095] S3. Perform 3D printing using an SLM metal printer;

[0096] The specific parameters are as follows: laser power 300W, laser scanning rate 800mm / s, laser scanning spacing 80μm, forming thickness of each layer of mixed powder 30μm, and interlayer rotation angle 60°;

[0097] Preheat the substrate of the SLM metal printer to 150°C before use;

[0098] Use argon as the printing atmosphere, and the printing size is 50mm×50mm×50mm;

[0099] S4. Heat treatment;

[0100] The specific process is as follows:

[0101] (a) Heat to 170°C at a rate of 8°C / min and hold for 2 hours;

[0102] (b) Cool to -30°C at a rate of 15°C / min and hold for 3 hours;

[0103] (c) Transfer to a spark plasma sintering furnace for holding, with a pulsed current density of 250A / cm 2 , a temperature of 180°C, a heating rate of 45°C / min, and a holding time of 40 minutes;

[0104] (d) Heat to 280°C at a rate of 25°C / min and hold for 1 hour;

[0105] (e) Cool naturally to room temperature.

[0106] Comparative Example 2

[0107] A method for preparing an aluminum alloy material, the specific steps are as follows:

[0108] S1. First, prepare aluminum alloy powder by water atomization method from the following components in mass percentages: Cu 4.1%, Mg 2.8%, Cr 2.5%, Si 1.2%, Mn 1.0%, Sc 0.3%, Zr 0.1%, Mo 0.08%, Ce 0.05%, Yb 0.05%, and the balance is Al;

[0109] Specifically, mix the components in the formula amounts, heat to 1000°C, and hold for 50 minutes to obtain a molten liquid; atomize the molten liquid with a citric acid-sodium citrate buffer solution (0.1mol / L, pH = 4.4), and dry to obtain the aluminum alloy powder;

[0110] The water atomization conditions are as follows: the diameter of the molten liquid flow is 25 mm, the temperature of the citric acid-sodium citrate buffer solution is 30 °C, the pressure is 90 MPa, and the flow rate is 180 m 3 / h, and the spraying angle is 20°;

[0111] S2. Then mix the aluminum alloy powder with BW2 (tungsten diboride) and VB2 (vanadium diboride) to obtain a mixed powder;

[0112] Specifically, first ultrasonically disperse 1 kg of aluminum alloy powder in 3 L of sodium dodecylbenzenesulfonate aqueous solution (mass concentration 1%) to obtain an aluminum alloy dispersion; then ultrasonically disperse 0.1 kg of BW2 and 0.1 kg of VB2 in 0.4 L of deionized water to obtain a suspension; then add the suspension to the aluminum alloy dispersion, stir well (stir at 400 r / min for 3 hours), filter to obtain the solid, and dry it to obtain; the particle size of BW2 and VB2 is 1500 mesh;

[0113] S3. Use an SLM metal 3D printer for 3D printing;

[0114] The specific parameters are as follows: the laser power is 300 W, the laser scanning rate is 800 mm / s, the laser scanning spacing is 80 μm, the forming thickness of each layer of mixed powder is 30 μm, and the interlayer rotation angle is 60°;

[0115] The substrate of the SLM metal 3D printer is preheated to 150 °C before use;

[0116] The printing atmosphere is argon, and the printing size is 50 mm × 50 mm × 50 mm;

[0117] S4. Heat treatment;

[0118] The specific process is as follows:

[0119] (a) Heat up to 170 °C at a rate of 8 °C / min and hold for 2 hours;

[0120] (b) Cool down to -30 °C at a rate of 15 °C / min and hold for 3 hours;

[0121] (c) Transfer to a spark plasma sintering furnace for heat preservation, the pulsed current density is 250 A / cm 2 , the temperature is 180 °C, the heating rate is 45 °C / min, and the holding time is 40 minutes;

[0122] (d) Heat up to 280 °C at a rate of 25 °C / min and hold for 1 hour;

[0123] (e) Naturally cool to room temperature.

[0124] The aluminum alloy materials obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to performance tests. Specifically, the tensile strength, yield strength, and elongation after fracture were tested on an electronic universal testing machine (model: AG-X 100kN), and the results are shown in Table 1.

[0125] Table 1. Results of aluminum alloy performance tests

[0126] Tensile strength (MPa) Yield strength (MPa) Elongation after fracture (%) Example 1 593 568 12.2 Example 2 595 572 12.2 Example 3 598 576 12.1 Comparative example 1 567 522 13.0 Comparative example 2 553 509 13.0

[0127] As can be seen from Table 1, the aluminum alloy materials obtained in Examples 1 to 3 have high tensile strength, yield strength, and elongation after fracture, and excellent performance.

[0128] In Comparative Example 1, vanadium boride was omitted, and in Comparative Example 2, polyacrylonitrile was omitted, and the strength was significantly deteriorated, indicating that the addition of BW2 (tungsten boride), VB2 (vanadium boride), and polyacrylonitrile is beneficial to the improvement of the strength of the aluminum alloy material.

[0129] The present invention illustrates the technical concept of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of individual raw materials of the products of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a high-strength aluminum alloy material, characterized in that, First, prepare aluminum alloy powder by water atomization method with the following components in mass percentage: Cu 4.1 - 4.5%, Mg 2.8 - 3.1%, Cr 2.5 - 2.8%, Si 1.2 - 1.5%, Mn 1.0 - 1.2%, Sc 0.3 - 0.5%, Zr 0.1 - 0.2%, Mo 0.08 - 0.1%, Ce 0.05 - 0.07%, Yb 0.05 - 0.07%, and the balance is Al; then mix the aluminum alloy powder with BW2, VB2, and polyacrylonitrile to obtain a mixed powder, and perform 3D printing using an SLM metal printer and heat treatment to obtain an aluminum alloy material.

2. The preparation method according to claim 1, characterized in that, The aluminum alloy powder is prepared by the following method: Mix the components in the formula amount and heat to 1000 - 1100 °C, keep warm for 50 - 60 minutes to obtain a molten liquid; atomize the molten liquid with water and dry it to obtain the aluminum alloy powder.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the aluminum alloy powder, BW2, VB2, and polyacrylonitrile is 1:0.1 - 0.2:0.1 - 0.2:0.1 - 0.

2.

4. The preparation method according to claim 1, characterized in that, The particle size of BW2 and VB2 is 1500 - 2000 mesh.

5. The preparation method according to claim 1, wherein, The mixed powder is prepared by the following method: First, ultrasonically disperse the aluminum alloy powder in an aqueous solution of sodium dodecylbenzenesulfonate to obtain an aluminum alloy dispersion; then ultrasonically disperse BW2 and VB2 in deionized water to obtain a suspension; then add the suspension and polyacrylonitrile solution to the aluminum alloy dispersion, stir well, filter to obtain the solid, and dry it to obtain the product.

6. The preparation method according to claim 1, wherein The specific parameters for 3D printing using an SLM metal printer are as follows: Laser power 300 - 350 W, laser scanning rate 800 - 900 mm / s, laser scanning spacing 80 - 90 μm, the forming thickness of each layer of the mixed powder is 30 - 40 μm, and the interlayer rotation angle is 60 - 62°.

7. The preparation method according to claim 1, characterized in that, The substrate of the SLM metal printer is preheated to 150 - 160 °C before use.

8. The preparation method according to claim 1, characterized in that, The specific process of heat treatment is as follows: (a) Heat at 8 - 10 °C / min to 170 - 180 °C and keep warm for 2 - 3 hours; (b) Cool at 15 - 18 °C / min to - 30 - 40 °C and keep warm for 3 - 4 hours; (c) Transfer to a spark plasma sintering furnace for heat preservation, with a pulsed current density of 250 - 280 A / cm 2 , a temperature of 180 - 200 °C, a heating rate of 45 - 50 °C / min, and a heat preservation time of 40 - 50 minutes; (d) Heat at 25 - 30 °C / min to 280 - 300 °C and keep warm for 1 - 2 hours; (e) Naturally cool to room temperature.

9. A high-strength aluminum alloy material, characterized in that, It is obtained by the preparation method described in any one of claims 1 - 8.