A high-strength aluminum alloy suitable for additive manufacturing and its preparation method

Abstract

This invention relates to a high-strength aluminum alloy suitable for additive manufacturing and its preparation method, belonging to the field of aluminum alloy materials. The high-strength aluminum alloy for additive manufacturing provided by this invention, by weight percentage, comprises: Mn: 4.0%–7.0%; Mg: 2.0%–4.0%; Sc: 0.55%–0.75%; Zr: 0.25%–0.55%; Nd: 0.1%–1.0%; Al: balance. The high-strength aluminum alloy mainly uses Mn, Mg, Sc, and Zr as base elements, with strict control over the element content ratio, and the addition of Nd. At room temperature, the resulting high-strength aluminum alloy exhibits a tensile strength above 610 MPa, a yield strength above 570 MPa, and an elastic modulus of approximately 79 GPa.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials, and more particularly to a high-strength aluminum alloy suitable for additive manufacturing and its preparation method. Background Technology

[0002] Additive manufacturing boasts excellent designability, enabling the rapid and precise forming of complex, thin-walled, and hollow components, and holds broad application prospects in fields such as aerospace. Aluminum alloys, as traditional lightweight structural materials, have become a key material for development and application in additive manufacturing technology. However, the commonly used aluminum alloy for additive manufacturing is AlSi10Mg, which has relatively low strength after stress-relief annealing, only around 300 MPa. Traditional high-strength aluminum alloys exhibit poor additive manufacturing process performance, resulting in numerous hot cracks in the microstructure after forming, failing to meet the requirements of additive manufacturing technology. Therefore, developing high-strength aluminum alloys suitable for additive manufacturing has become an important direction for further development of aluminum alloys in additive manufacturing.

[0003] The earliest high-strength aluminum alloy specifically for additive manufacturing was the Al-Mg-Sc series high-strength aluminum alloy, Scalmalloy. This alloy has a chemical composition of Al-4.6Mg-0.66Sc-0.42Zr-0.49Mn (wt%) and a tensile strength of approximately 500 MPa. Currently, this alloy is used in the additive manufacturing of cabin structural components for the Airbus A320 aircraft. With continuous development, more and more people are attempting to improve the Al-Mg-Sc series high-strength aluminum alloy. However, the room temperature tensile strength of the improved Al-Mg-Sc series high-strength aluminum alloy is below 600 MPa, and the yield strength is below 570 MPa.

[0004] When the aforementioned high-strength aluminum alloys are additively manufactured, the loss of low-melting-point alloying elements leads to deviations in the alloy composition, resulting in numerous oxide inclusions, voids, cracks, and other defects that affect the continuity, integrity, and strength of the alloy's microstructure. Therefore, there is an urgent need for a high-strength aluminum alloy with high strength to meet the requirements of additive manufacturing. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a high-strength aluminum alloy suitable for additive manufacturing and a method for preparing the same, in order to solve the problem of low strength of existing aluminum alloys.

[0006] On the one hand, the present invention provides a high-strength aluminum alloy suitable for additive manufacturing, comprising, by weight percentage: Mn: 4.0% to 7.0%; Mg: 2.0% to 4.0%; Sc: 0.55% to 0.75%; Zr: 0.25% to 0.55%; Nd: 0.1% to 1.0%; Al: balance.

[0007] Furthermore, the high-strength aluminum alloy also includes X; wherein X is selected from one or more of Cu, Ti, and Si.

[0008] Further, X is Cu, with Cu content ranging from 0.1% to 0.6%.

[0009] Further, X is Ti and Si, where Ti: 0.05%–0.2%; Si: 0.7%–1.2%.

[0010] Further, X is Cu and Si, where Cu: 0.1%–0.6%; Si: 0.7%–1.2%.

[0011] Further, X is Cu and Ti, with Cu: 0.1% to 0.6% and Ti: 0.05% to 0.2%.

[0012] Further, X is Cu, Ti, and Si; Cu: 0.1%–0.6%; Ti: 0.05%–0.2%; Si: 0.7%–1.2%.

[0013] Furthermore, the high-strength aluminum alloy has a tensile strength of over 610 MPa and a yield strength of over 570 MPa.

[0014] On the other hand, the present invention provides a method for preparing the high-strength aluminum alloy for additive manufacturing, which combines gas atomization sieving and additive manufacturing.

[0015] Furthermore, the method for preparing the high-strength aluminum alloy for additive manufacturing includes the following steps:

[0016] S1: Powder preparation, preparing alloy raw materials into alloy powder;

[0017] S2: Powder processing, which involves sieving, mixing and drying the obtained alloy powder;

[0018] S3: Additive manufacturing, which uses laser powder bed melting technology to add materials to processed alloy powders;

[0019] S4: A high-strength aluminum alloy obtained after heat treatment.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] 1. This invention provides a high-strength aluminum alloy primarily based on Mn, Mg, Sc, and Zr as base elements, with strict control over the element content ratio. Furthermore, the addition of Nd can form Al3Nd or Al... 11Intermetallic compounds such as Nd3 hinder dislocation migration and exert the orovan strengthening effect; at the same time, these intermetallic compounds have good thermal stability and can effectively inhibit recrystallization and grain growth during heat treatment, ensuring grain boundary strengthening.

[0022] 2. This invention, through the combination of alloy components and the use of gas atomization sieving and additive manufacturing methods, produces a high-strength aluminum alloy with an internal microstructure of layered, fish-scale-like molten pools. The microstructure is dense and free of obvious cracks, pores, or other defects. Performance testing shows that at room temperature, the obtained high-strength aluminum alloy exhibits a tensile strength exceeding 610 MPa, a yield strength exceeding 570 MPa, and an elastic modulus of approximately 79 GPa, which is higher than that of existing additively manufactured aluminum alloys (69–72 GPa), enabling it to withstand higher impact loads.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 The image shows the metallographic structure of the aluminum alloy obtained in Example 1.

[0026] Figure 2 The image shows the metallographic structure of the aluminum alloy obtained in Example 2;

[0027] Figure 3 The image shows the metallographic structure of the aluminum alloy obtained in Example 3;

[0028] Figure 4 The image shows the metallographic structure of the aluminum alloy obtained in Example 4;

[0029] Figure 5 The image shows the metallographic structure of the aluminum alloy obtained in Example 5;

[0030] Figure 6 The image shows the metallographic structure of the aluminum alloy obtained in Example 6;

[0031] Figure 7 The image shows the metallographic structure of the aluminum alloy obtained in Example 7;

[0032] Figure 8 The image shows the metallographic structure of the aluminum alloy obtained in Example 8;

[0033] Figure 9 The image shows the metallographic structure of the aluminum alloy obtained in Comparative Example 1.

[0034] Figure 10 The image shows the metallographic structure of the aluminum alloy obtained in Comparative Example 2.

[0035] Figure 11 The image shows the metallographic structure of the aluminum alloy obtained in Comparative Example 3.

[0036] Figure 12 The image shows the metallographic structure of the aluminum alloy obtained in Comparative Example 4.

[0037] Figure 13 Here is a metallographic photograph of the aluminum alloy obtained in Example 11;

[0038] Figure 14 The image shows the metallographic structure of the aluminum alloy obtained in Example 12;

[0039] Figure 15 A metallographic photograph of the aluminum alloy obtained in Comparative Example 5;

[0040] Figure 16 The image shows the metallographic structure of the aluminum alloy obtained in Comparative Example 6.

[0041] Figure 17 The image shows the actual product of the obtained aluminum alloy. Detailed Implementation

[0042] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0043] Aluminum alloys, as traditional lightweight structural materials, have a wide range of applications, such as in aerospace. Additive manufacturing offers excellent designability, enabling the rapid and precise forming of complex, thin-walled, and hollow parts. The combination of aluminum alloys and additive manufacturing is an important direction for development.

[0044] The existing aluminum alloy is AlSi10Mg. After additive manufacturing, its strength is around 300MPa. Through continuous research, Al-Mg-Sc series high-strength aluminum alloys have been gradually developed. After many years of development or improvement, the room temperature tensile strength of aluminum alloys after additive manufacturing is below 600MPa and the yield strength is below 570MPa. Moreover, it will form more oxide inclusions or defects such as pores and cracks, making it unsuitable for use in environments with higher requirements.

[0045] Therefore, the present invention provides a high-strength aluminum alloy suitable for additive manufacturing, comprising, by weight percentage: Mn: 4.0%–7.0%; Mg: 2.0%–4.0%; Sc: 0.55%–0.75%; Zr: 0.25%–0.55%; Nd: 0.1%–1.0%; Al: balance.

[0046] Compared with existing technologies, the present invention provides a high-strength aluminum alloy mainly based on Mn, Mg, Sc and Zr as base elements, with strict control over the content ratio of these elements, and the addition of Nd can form Al3Nd or Al 11 Intermetallic compounds such as Nd3 hinder dislocation migration and exert an orovan strengthening effect. Simultaneously, these intermetallic compounds exhibit good thermal stability, effectively suppressing recrystallization and grain growth during heat treatment, ensuring grain boundary strengthening. Therefore, the above composition scheme helps guarantee the strength of the aluminum alloy obtained after additive manufacturing, resulting in a denser high-strength aluminum alloy microstructure free from defects such as pores and cracks.

[0047] Specifically, high-strength aluminum alloys also include X, where X is selected from one or more of Cu, Ti, and Si.

[0048] It should be noted that after heat treatment, Cu can form the Ω'-Al2CuMg phase with Al and Mg, or the θ'-Al2Cu phase with Al. Under the influence of Al3Sc or Al3Zr precipitates, these phases exhibit good stability and can exert precipitation strengthening effects. The addition of Ti can form the L12-type intermetallic compound Al3Ti, which is coherent with the Al matrix. This phase also exhibits good precipitation strengthening and thermal stability. Si can form the Si-rich quasicrystalline phase AlMnSi in this alloy, improving the thermal stability of the quasicrystalline phase and the Orovan strengthening effect.

[0049] Specifically, X is Cu, with Cu content ranging from 0.1% to 0.6%.

[0050] Specifically, X is Ti, where Ti is 0.05% to 0.2%.

[0051] Specifically, X is Si, where Si is 0.7% to 1.2%.

[0052] Specifically, X is Ti and Si, with Ti: 0.05% to 0.2% and Si: 0.7% to 1.2%.

[0053] Specifically, X is Cu and Si, with Cu: 0.1% to 0.6% and Si: 0.7% to 1.2%.

[0054] Specifically, X is Cu and Ti, with Cu: 0.1% to 0.6% and Ti: 0.05% to 0.2%.

[0055] Specifically, X is Cu, Ti, and Si; Cu: 0.1%–0.6%; Ti: 0.05%–0.2%; Si: 0.7%–1.2%.

[0056] It should be noted that the elements in this invention serve the following functions:

[0057] Mn: Manganese, as the main alloying element, lays the foundation for the forming process adaptability and performance of the aluminum alloy of this invention. On the one hand, the addition of 4% to 7% Mn keeps the alloy near the Al-Mn eutectic composition, with a narrow solid-liquid phase temperature range, resulting in good adaptability to additive manufacturing processes. On the other hand, Mn has a large lattice mismatch strain with Al, and the addition of Mn can achieve a significant solid solution strengthening effect. In addition, Mn has a low thermal diffusivity in the Al matrix, resulting in less Mn precipitation during subsequent heat treatment, maintaining a high level of solid solution strengthening effect. Even if some Mn atoms precipitate, they can form a relatively stable quasi-crystalline phase with Al and Si, achieving an Orovan strengthening effect.

[0058] Mg: Magnesium has high solid solubility in Al matrix, resulting in good solid solution strengthening effect. However, this element is highly reactive and has a low melting / boiling point, making it prone to burn-off or evaporation during additive manufacturing. Therefore, the addition amount is controlled between 2.0% and 4.0%.

[0059] Scandium (Sc) is a precipitation strengthening element in the aluminum alloy of this invention. However, this element is expensive. When added at a concentration of 0.55% to 0.75%, it can form a considerable volume fraction of Al3Sc intermetallic compound in the aluminum alloy, thereby refining the grains and achieving precipitation strengthening effects.

[0060] Zr: Zirconium can form Al3Zr with an L12 structure, which exhibits good thermal stability. When Zr and Sc coexist, Zr atoms partially replace Sc atoms in the Al3Sc intermetallic compound to form Al3(Sc). 1-x Zr x Pseudo-binary phase. However, excessive amounts of this phase can reduce the content of Al3(Sc). 1-x Zr x The stability of the pseudo-binary phase is detrimental to achieving good precipitation enhancement. Therefore, the addition amount of Zr is 0.25% to 0.55%.

[0061] Nd: Neodymium can form Al3Nd or Al with Al. 11 Intermetallic compounds such as Nd3 inhibit dislocation migration, thus exerting the orovan strengthening effect. Simultaneously, their good thermal stability effectively suppresses recrystallization and grain growth during heat treatment, ensuring grain boundary strengthening. To balance cost and performance improvement, their addition amount is 0.1%–1.0%.

[0062] Cu: After heat treatment, copper can form Ω'-Al2CuMg phase with Al and Mg, or θ'-Al2Cu phase with Al. It exhibits good stability under the inhibitory effect of Al3Sc or Al3Zr precipitates, thus achieving precipitation strengthening. Due to the limited amount of Al3Sc or Al3Zr precipitates, the amount of Cu added should not be excessive, generally 0.1% to 0.6%.

[0063] The addition of titanium can form an L12-type intermetallic compound, Al3Ti, coherent with the Al matrix, exhibiting a certain precipitation strengthening effect. However, this phase can transform from L12 to DO. 22 The crystal structure changes, resulting in relatively poor stability. Therefore, the amount added is small, only 0.05% to 0.2%.

[0064] Si: Silicon can form a Si-rich quasicrystalline phase AlMnSi in the aluminum alloy of this invention, improving the thermal stability and orovan strengthening effect of the quasicrystalline phase. Considering the amount of Mn precipitated to form the quasicrystalline phase, the optimal amount of Si added is 0.7% to 1.2%.

[0065] This invention provides a method for preparing high-strength aluminum alloys for additive manufacturing, which combines gas atomization sieving and additive manufacturing, and includes the following steps:

[0066] S1: Powder preparation, preparing alloy raw materials into alloy powder;

[0067] S2: Powder processing, which involves sieving, mixing and drying the obtained alloy powder;

[0068] S3: Additive manufacturing, which uses laser powder bed melting technology to add materials to processed alloy powders;

[0069] S4: A high-strength aluminum alloy obtained after heat treatment.

[0070] Compared with existing technologies, this invention, through alloy composition matching and the use of gas atomization sieving and additive manufacturing methods, produces a high-strength aluminum alloy with an internal microstructure of layered, fish-scale-like molten pools. This structure is dense and free of obvious cracks, pores, or other defects. Performance testing shows that at room temperature, the resulting high-strength aluminum alloy exhibits a tensile strength exceeding 610 MPa, a yield strength exceeding 570 MPa, and an elastic modulus of approximately 79 GPa, which is higher than that of existing additively manufactured aluminum alloys (69–72 GPa), enabling it to withstand higher impact loads.

[0071] It should be noted that aluminum ingots, magnesium ingots, aluminum-based master alloy ingots, or alloy preforms are used as raw materials. The materials are smelted in a vacuum atomizing furnace under an inert atmosphere, and the molten metal is broken up by high-pressure inert gas to prepare the matrix alloy powder. The alloy powder is then cooled in an inert atmosphere.

[0072] Specifically, after sieving, the particle size of the alloy powder is ≤200μm.

[0073] Preferably, after sieving, the particle size of the alloy powder is ≤75μm.

[0074] It should be noted that if the alloy powder particle size is too large, the melting power required by light sources such as high-energy laser beams or electron beams is higher, making it easier to cause the alloy elements to burn off or oxidize. Furthermore, excessively large particle sizes result in high surface roughness, which is detrimental to ensuring dimensional accuracy and surface quality. Additive manufacturing processes typically use alloy powders with a particle size no larger than 200 μm.

[0075] Specifically, the sieved alloy powder is mixed at a speed of 1 r / min to 15 r / min for a duration of 10 min to 60 min.

[0076] Preferably, the rotation speed is 5 r / min to 10 r / min, and the duration is 10 min to 30 min.

[0077] It should be noted that the above-mentioned rotation speed and duration can effectively achieve powder mixing, resulting in uniform particle size and composition without significant agglomeration. Too low a rotation speed will not achieve sufficient mixing; too high a rotation speed will intensify friction between powders, easily causing surface oxidation. Too short a duration will result in insufficient mixing; too long a duration will lead to increased static electricity accumulation on the powder surface, easily causing powder agglomeration.

[0078] Specifically, during the drying process, the mixed powder is placed in a tray and spread evenly with a thickness of no more than 2 cm. It is then placed in an explosion-proof drying oven and dried at 60℃~150℃ for 1~10 hours, followed by oven cooling.

[0079] Preferably, the drying temperature is 100℃~120℃, and the drying time is 1.5~3h.

[0080] It should be noted that drying facilitates subsequent additive manufacturing, ensuring the strength and quality of the resulting aluminum alloy. If the drying temperature is too low or the drying time is too short, it cannot effectively remove surface-adsorbed moisture or oxygen; if the temperature is too high or the drying time is too long, it will lead to more severe oxidation of the alloy powder, resulting in a relatively poor quality aluminum alloy.

[0081] Specifically, the additive manufacturing process employs a strip scanning strategy with a laser power of 235–295W, a scanning rate of 1500–1700 mm / s, a powder layer thickness of 20–45 μm, and an overlap spacing of 0.1–0.2 mm.

[0082] Preferably, the laser power is 255-275W and the scanning rate is 1550-1650mm / s.

[0083] Specifically, the additive manufacturing process uses argon gas for protection, controls the oxygen content of the atmosphere to be below 100 ppm, the substrate preheating temperature is 50-250°C, and the number of repeated scans is 0-1.

[0084] It should be noted that the parameters of the additive manufacturing process are closely related to the room temperature properties of the final aluminum alloy. When the laser power is too high, the scanning rate is too low, the powder layer is too thick, and the overlap spacing is too small, the volumetric energy density will be too high, and the low-boiling-point elements in the melt will easily evaporate, resulting in the formation of circular pores in the microstructure. Conversely, when the volumetric energy density is too low (laser power is too low, scanning speed is too high, or the powder layer is too thick and the overlap spacing is too large), the input energy is insufficient to completely remelt the alloy powder in a unit volume, resulting in defects such as irregular pores and unmelted powder.

[0085] In addition, to reduce oxidation loss during additive manufacturing, an inert gas (argon) is used for protection, and the oxygen content in the forming chamber is ensured to be below 100 ppm. Excessive oxygen content will lead to severe oxidation loss, destroy the continuity and integrity of the microstructure, and ultimately result in a decrease in mechanical properties.

[0086] Preheating the substrate can effectively control the cooling rate of the melt during forming and suppress the tendency of the alloy to crack. However, excessively high preheating temperatures can reduce the solid solution strengthening effect and decrease the amount of precipitated strengthening phases after heat treatment, thus reducing the precipitation strengthening effect. Since this alloy has good adaptability to forming processes, a preheating temperature of 50–250°C is selected to ensure mechanical properties.

[0087] For critical structures or areas with high stress concentration, repeated scanning can release stress or ensure the density of critical structures; however, excessive repetitions can also cause excessive burn-off or oxidation. Therefore, the number of repeated scans is selected to be 0 to 1.

[0088] Specifically, the heating temperature for heat treatment is 300–360℃, and the holding time is 1.5–12 hours.

[0089] It should be noted that the present invention controls the heating temperature of the heat treatment to be between 300 and 360°C and the holding time to be between 1.5 and 12 hours, which is beneficial for the oxidation of Al3(Sc,Zr), Al3Zr, Al3Nd, or Al in aluminum alloys. 11 The precipitation of Nd3 and the transformation of the quasicrystalline phase AlMnSi are important. When the temperature is too low or the holding time is too short, the sufficient precipitation of the precipitation-strengthening phase cannot be guaranteed. When the temperature is too high or the holding time is too long, the precipitate will undergo unnecessary coarsening and growth, weakening the precipitation-strengthening effect.

[0090] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0091] Example 1

[0092] The preparation process of high-strength aluminum alloy is as follows:

[0093] S1: Powder preparation: The alloy raw materials aluminum ingot, magnesium ingot and aluminum-based master alloy ingot are weighed in proportion, placed in a crucible and melted. The molten alloy liquid is broken up by nitrogen gas to prepare alloy powder. The alloy powder is cooled in an inert atmosphere.

[0094] S2: Powder processing: The alloy powder is sieved to obtain alloy powder with a size of ≤71μm. The alloy powder is then added to a mixer and mixed at a speed of 10r / min for 30min. The mixed alloy powder is then placed in a tray and spread evenly to a thickness of 1.5cm. It is then placed in an explosion-proof drying oven and dried at 120℃ for 1.5h, followed by furnace cooling.

[0095] S3: Additive manufacturing, using laser powder bed melting equipment for forming, employing a strip scanning strategy, laser power 265W, scanning rate 1600mm / s, powder layer thickness 40μm, overlap spacing 0.12mm; the forming process is protected by argon gas, controlling the oxygen content of the atmosphere to 60ppm; the substrate preheating temperature during the forming process is 100℃; the number of repeated scans is 0; after cooling, it is taken out.

[0096] S4: The sample was heat-treated in a heating furnace at a holding temperature of 310℃ for 9 hours and then cooled in the furnace to obtain a high-strength aluminum alloy.

[0097] Examples 2-10, Comparative Examples 1-4

[0098] Examples 2-10 and Comparative Examples 1-4 differ from Example 1 in their alloy composition, as shown in Table 1.

[0099] Table 1. Different parameters for Examples 1-10 and Comparative Examples 1-4 (unit: wt%)

[0100]

[0101]

[0102] *In Table 1, "-" indicates that it does not contain.

[0103] Performance testing

[0104] The microstructure, tensile strength, yield strength, and elastic modulus of the materials in Examples 1-10 and Comparative Examples 1-4 were observed or tested according to GB / T 3246.1-2012, GB / T228.1-2010, GB / T 22315-2008, or HB 5143-1996, respectively. The results are shown in Table 2, and the microstructure photographs are as follows. Figure 1-12 As shown.

[0105] Table 2 Performance Test Results

[0106]

[0107]

[0108] Based on Examples 1-10 and Comparative Examples 1-4, and in conjunction with Table 2, it can be seen that when the components are formulated according to the proportions shown in Examples 1-10, the resulting aluminum alloy has a yield strength of over 572 MPa, a tensile strength of over 615 MPa, an elastic modulus of over 78 GPa, a dense structure, and no obvious cracks, pores, or other defects.

[0109] Examples 11-15, Comparative Examples 5-6

[0110] Examples 11-15 and Comparative Examples 5-6 differ from Example 1 in that they are prepared using different methods, as detailed in Table 3.

[0111] Table 3. Different parameters between Examples 11-15, Comparative Examples 5-6 and Example 1

[0112] Group Laser power / W Scan rate mm / s Powder layer thickness / μm Heat treatment Example 1 265 1600 40 310℃-9h Example 11 235 1600 30 310℃-9h Example 12 265 1600 30 310℃-9h Example 13 295 1600 30 310℃-9h Example 14 265 1500 30 310℃-9h Example 15 265 1700 30 310℃-9h Comparative Example 5 205 1600 30 310℃-9h Comparative Example 6 325 1600 30 310℃-9h

[0113] Performance testing

[0114] The microstructure, tensile strength, yield strength, and elastic modulus of the materials in Examples 11-15 and Comparative Examples 5-6 were observed or tested according to GB / T 3246.1-2012, GB / T228.1-2010, GB / T 22315-2008, or HB 5143-1996, respectively. The results are shown in Table 4, and the microstructure photographs are as follows. Figure 13-16 As shown in Figure 17, the actual object is also shown in the figure.

[0115] Table 4 Performance Test Results

[0116]

[0117] In conjunction with Examples 1, 11-15, Comparative Examples 5-6, and Table 4, it can be seen that when the preparation methods of Examples 1 and 11-15 of the present invention are used, the tissue density can reach more than 99.6%, and there are no large-sized circular pores or irregular holes; and the yield strength is more than 572 MPa, the tensile strength is more than 612 MPa, and the elastic modulus is more than 78 GPa.

[0118] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-strength aluminum alloy suitable for additive manufacturing, characterized in that, By weight percentage, it includes Mn: 6.6%~7.0%; Mg: 2.0%~4.0%; Sc: 0.55%~0.75%; Zr: 0.25%~0.55%; Nd: 0.2%~1.0%; Al: Balance; The high-strength aluminum alloy is prepared by a combination of gas atomization sieving and additive manufacturing, including the following steps: S1: Powder preparation, preparing alloy raw materials into alloy powder; S2: Powder processing, which involves sieving, mixing and drying the obtained alloy powder; S3: Additive manufacturing, which uses laser powder bed melting technology to add materials to processed alloy powders; S4: A high-strength aluminum alloy obtained through heat treatment; wherein the heating temperature of the heat treatment is 300~360℃, and the holding time is 1.5~12h, which is beneficial to the extraction of Al3(Sc, Zr), Al3Zr, Al3Nd or Al from the aluminum alloy. 11 Precipitation of Nd3 and transformation of the quasicrystalline phase AlMnSi; At room temperature, the high-strength aluminum alloy has a tensile strength of over 610 MPa and a yield strength of over 570 MPa; the internal structure of the obtained high-strength aluminum alloy is a fish-scale molten pool layer-by-layer stacked morphology.

2. The high-strength aluminum alloy suitable for additive manufacturing according to claim 1, characterized in that, It also includes X; wherein X is selected from one or more of Cu, Ti and Si.

3. The high-strength aluminum alloy suitable for additive manufacturing according to claim 2, characterized in that, X is Cu, with Cu content ranging from 0.1% to 0.6%.

4. The high-strength aluminum alloy suitable for additive manufacturing according to claim 2, characterized in that, X is Ti and Si, with Ti: 0.05%~0.2%; Si: 0.7%~1.2%.

5. The high-strength aluminum alloy suitable for additive manufacturing according to claim 2, characterized in that, X is Cu and Si, with Cu: 0.1%~0.6%; Si: 0.7%~1.2%.

6. The high-strength aluminum alloy suitable for additive manufacturing according to claim 2, characterized in that, X is Cu and Ti, with Cu: 0.1%~0.6%; Ti: 0.05%~0.2%.

7. The high-strength aluminum alloy suitable for additive manufacturing according to claim 2, characterized in that, X is Cu, Ti, and Si; Cu: 0.1%~0.6%; Ti: 0.05%~0.2%; Si: 0.7%~1.2%.

8. A method for preparing a high-strength aluminum alloy for additive manufacturing as described in any one of claims 1-7, characterized in that, It is prepared by combining gas atomization sieving and additive manufacturing.

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