Additive manufacturing-oriented high-performance aluminum alloy component system and method thereof

Abstract

The invention discloses a high-performance aluminum alloy component system for additive manufacturing and a method thereof. The high-performance aluminum alloy comprises the following components in percentage by mass: 0.8%-2.5% of Mg, 1.5%-5.5% of Mn, 0.6%-0.8% of Sc, 0.4%-0.7% of Zr and Olt. 0.06%, and Silt; 0.2%, and the balance being Al. Therefore, by optimizing the content of Mg and Mn elements, not only can the balance of high strength and toughness be realized, but also the performance can be adjusted according to the functional requirements of parts so as to adapt to complex working conditions. According to the method, a new thought is provided for high-performance application of the additive manufacturing technology in the aerospace field, and the design goals of light weight and structure complication are assisted to be achieved.

Description

Technical Field

[0001] The present invention relates to a high-performance aluminum alloy composition system for additive manufacturing and a method for preparing powders thereof, belonging to the technical field of special processing of laser additive manufacturing. Background Art

[0002] In recent years, due to the processing characteristics of layer-by-layer stacking, additive manufacturing technology can rapidly and accurately manufacture complex-structured parts, and has become an important direction of modern manufacturing technology. In the aerospace field, with the continuous advancement of lightweight requirements and complex structure designs, additive manufacturing aluminum alloys have attracted much attention due to their high performance and low density characteristics. Currently, the commonly used aluminum alloy systems in laser additive manufacturing include Al-Si-based, Al-Mg-based, and Al-Cu-based alloys, and each type of alloy has its own characteristics in terms of performance and processing adaptability. Al-Si-based alloys, due to their near-eutectic composition, have good fluidity and formability during the forming process, and can generate fine grains, significantly improving the surface quality. However, their strength and toughness are relatively limited, and it is difficult to meet the usage requirements of high-strength load-bearing structures. Al-Cu-based alloys are known for their excellent strength performance, but due to their high thermal cracking sensitivity during the laser additive manufacturing process, they are prone to cracking, reducing the reliability of the materials. In addition, such alloys have high requirements for heat treatment processes, and the manufacturing process is complex, increasing the process difficulty. In contrast, Al-Mg-based alloys have become a research hotspot due to their high specific strength and good corrosion resistance. Among them, the AlMgScZr alloy, as a material developed specifically for additive manufacturing, has both excellent formability and mechanical properties. However, due to the high Mg content, spattering and "black slag" phenomena are likely to occur during the additive manufacturing process, which not only deteriorates the fracture toughness but also poses potential hazards to the safety of operators and equipment. In addition, the high Mg content increases the process difficulty, especially posing higher requirements for the stability of the filter system.

[0003] With the continuous improvement of the performance requirements for structural parts in the aerospace field, due to the differences in working environments and load-bearing methods of parts in different positions, the demand for material properties is becoming increasingly diverse. For example, some load-bearing components require high strength and fracture toughness, while other components may pay more attention to ductility. This complexity drives the development of additive manufacturing aluminum alloys towards customized design, and through precise regulation of alloy composition design, targeted optimization of performance is achieved. Summary of the Invention

[0004] The objective of the present invention is to provide a high-performance aluminum alloy composition system for additive manufacturing, so as to customize and design additive manufacturing aluminum alloy powders with different mechanical property characteristics to meet diverse performance requirements. By optimizing the contents of Mg and Mn elements, not only can the balance between high strength and toughness be achieved, but also the performance can be adjusted according to the functional requirements of parts to adapt to complex working conditions. This method provides a new idea for the high-performance application of additive manufacturing technology in the aerospace field, helping to achieve the design goals of lightweight and complex structures.

[0005] To achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0006] A high-performance aluminum alloy composition system for additive manufacturing, by mass percentage, includes: Mg: 0.8%-2.5%, Mn: 1.5-5.5%, Sc: 0.6-0.8%, Zr: 0.4-0.7%, O < 0.06% and Si < 0.2%, and the balance is Al.

[0007] Preferably, the content of Mg is: 0.8-1.4%, and the content of Mn is: 4.5-5.5%.

[0008] Preferably, the content of Mg is: 1.5-2.5%, and the content of Mn is: 3.5-4.5%.

[0009] Preferably, the content of Mg is: 1.5-2.5%, and the content of Mn is: 1.5-2.5%.

[0010] A method for preparing powders of a high-performance aluminum alloy composition system for additive manufacturing, comprising the following steps:

[0011] Step 1: Design the component ratios of the high-performance aluminum alloy composition system:

[0012] The components of the high-performance aluminum alloy composition system include Mg, Mn, Sc, Zr, O, Si and Al;

[0013] Based on the alloy phase diagram and the solid solution strengthening principle, calculate the ratios of Mg element and Mn element with better solid solution strengthening effects, and satisfy:

[0014] y = -15.6261x 5 +111.1631x 4 -312.7712x 3 +434.5672x 2 -298.2785x + 86.1335;

[0015] Where: y is the mass content of Mn element in the high-performance aluminum alloy composition system, with a value range of 1.5 - 5.5%; x is the mass content of Mg element in the high-performance aluminum alloy composition system, with a value range of 0.8% - 2.5%;

[0016] Powders are prepared respectively based on the calculated Mg-Mn element ratio. The mass contents of other components are: Sc: 0.6 - 0.8%, Zr: 0.4 - 0.7%, O < 0.06% and Si < 0.2%, and the rest is Al;

[0017] Step Two: Prepare the printing powder system:

[0018] Prepare the high-performance aluminum alloy composition system according to the component ratios of the high-performance aluminum alloy composition system designed in Step One. Then, after atomization, passivation, screening, and drying treatments in sequence, a printing powder system suitable for additive manufacturing can be obtained. The component ratios in the obtained printing powder system need to meet the component ratios of the high-performance aluminum alloy composition system designed in Step One.

[0019] Preferably, in Step Two, the atomization is carried out using a vacuum atomization device, and the atomization process parameters are: set the atomization temperature at 820 - 850 °C, the atomization pressure at 2.0 - 2.5 MPa, and the diameter of the diversion tube is 4.2 mm.

[0020] Preferably, in the high-performance aluminum alloy composition system prepared in Step One, the Mg content is: 0.8 - 1.4%, and the Mn content is: 4.5 - 5.5%;

[0021] Or in the high-performance aluminum alloy composition system prepared in Step One, the Mg content is: 1.5 - 2.5%, and the Mn content is: 3.5 - 4.5%;

[0022] Or in the high-performance aluminum alloy composition system prepared in Step One, the Mg content is: 1.5 - 2.5%, and the Mn content is: 1.5 - 2.5%.

[0023] The third technical objective of the present invention is to provide a laser additive manufacturing method for high-performance aluminum alloy components, including the following steps:

[0024] Step A: Prepare the printing powder system:

[0025] The printing powder system is made based on the powder preparation method of the high-performance aluminum alloy composition system for additive manufacturing described in Claim 5;

[0026] Step B: Laser additive manufacture high-performance aluminum alloy components:

[0027] Step B.1: Use 3D modeling software to establish a 3D solid geometric model of the high-performance aluminum alloy component, and use slicing software to slice and layer the established 3D solid geometric model to obtain a series of stacked slice layers. Then, plan corresponding laser printing strategies for each slice layer and set the printing forming parameters: laser power 370W, scanning speed 1100mm / s, scanning spacing 0.12mm / s, stripe width 80μm, stripe offset 0.06mm, layer thickness 30μm. Generate a slice data processing file and import the slice data processing file into the laser additive manufacturing forming equipment;

[0028] Step B.2: Debug the laser additive manufacturing forming equipment;

[0029] Step B.3: Introduce argon gas into the forming cylinder of the laser additive manufacturing forming equipment and ensure that a low-oxygen environment can be maintained in the forming cylinder during the forming process;

[0030] Load the high-performance aluminum alloy composition system after being dried in Step 4 into the powder cylinder;

[0031] Step B.4: Under the control of the slice data processing file, laser melt each slice layer layer by layer on the substrate of the laser additive manufacturing forming equipment until the laser melting and solidification of all slice layers are completed;

[0032] Step B.5: After the forming is completed, let it stand for a period of time, then take out the formed component and conduct heat treatment.

[0033] Preferably, in Step B.5, the process parameters of the heat treatment are: holding temperature 300°C, holding time 2h.

[0034] Preferably, in Step B.3, the oxygen content in the low-oxygen environment is less than 100ppm.

[0035] Based on the above technical objectives, compared with the prior art, the present invention has the following advantages:

[0036] Aiming at the problems brought by the high Mg content of the existing high-strength aluminum powder, the present invention introduces Mn element to replace part of the Mg element. That is, the present invention abandons the high Mg content in the traditional Al-Mg-Sc-Zr alloy, introduces Mn element to conduct solid solution strengthening together with Mg, can enhance the melt fluidity, inhibit the formation of intergranular hot cracks, and improve the powder yield. And by establishing the relationship formula between the Mg content and the Mn content, the contents of the Mg element and the Mn element can be determined quickly and accurately. Description of the Drawings

[0037] Figure 1 is the powder morphology of the high-performance aluminum alloy composition system for additive manufacturing according to the present invention; Figure 2Tensile specimens and fracture toughness specimens made by the laser additive manufacturing method of the high-performance aluminum alloy components described in the present invention; Figure 3 It is a comparison diagram of the side roughness of specimens of three preferred embodiments; Figure 4 It is a comparison diagram of the tensile strength of specimens of three preferred embodiments; Figure 5 It is a comparison diagram of the elongation of specimens of three preferred embodiments; Figure 6 It is the fracture toughness K of specimens of three preferred embodiments IC Comparison diagram; Figure 7 It is the load-displacement curve diagram of the fracture toughness test of the specimen of Example 2; Figure 8 It is the load-displacement curve diagram of the fracture toughness test of the specimen of Example 3; Figure 9 It is the failure analysis diagram of the fracture path of the specimen of Example 3.

[0038] Figure 10 It is a comparison diagram of the tensile strength, elongation and fracture toughness of specimens of the powders prepared in Examples 3-5. Specific embodiments

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangements, expressions and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0047] The high-performance aluminum alloy composition system for additive manufacturing according to the present invention addresses the problems caused by the high Mg content in existing high-strength aluminum powders. It introduces Mn element to replace part of the Mg element, enabling solid solution strengthening of Mn and Mg together, enhancing the melt fluidity, inhibiting the formation of intergranular hot cracks, and increasing the powder yield.

[0048] Specifically, the components of the high-performance aluminum alloy composition system of the present invention include Mg, Mn, Sc, Zr, O, Si, and Al. To determine the ratio of each component, the present invention first calculates the ratio of Mg and Mn elements with better solid solution strengthening effect based on the alloy phase diagram and the principle of solid solution strengthening, and satisfies:

[0049] y = -15.6261x 5 +111.1631x 4 -312.7712x 3 +434.5672x 2 -298.2785x + 86.1335;

[0050] In the formula: y is the mass content of Mn element in the high-performance aluminum alloy composition system, with a value of 1.5 - 5.5%; x is the mass content of Mg element in the high-performance aluminum alloy composition system, with a value of 0.8% - 2.5%.

[0051] Then, based on the calculated Mg-Mn element ratio, powders are prepared respectively. The mass contents of other components are: Sc: 0.6 - 0.8%, Zr: 0.4 - 0.7%, O < 0.06%, and Si < 0.2%, and the rest is Al.

[0052] It can be seen that the present invention addresses the problems caused by the high Mg content in existing high-strength aluminum powders, introduces Mn element to replace part of the Mg element, and quickly determines the contents of Mg and Mn elements according to the above content relationship of Mg and Mn. On the one hand, it optimizes the composition design scheme of the existing aluminum alloy composition system to ensure the high strength and high toughness performance of the formed components. On the other hand, it also simplifies the determination of the ratios of each component in the aluminum alloy composition system, facilitating popularization and utilization.

[0053] After measuring the high-performance aluminum alloy composition system according to the above ratio, it is atomized using a laboratory vacuum gas atomization VIGA device to obtain atomized powder. The atomization process parameters are: atomization temperature 820 - 850 °C, atomization pressure 2.0 - 2.5 MPa, and the diameter of the guide tube is 4.2 mm. After 24 hours of passivation treatment of the atomized powder, it is sieved to obtain a printing powder system with a particle size distribution suitable for LPBF, and ensure that the prepared printing powder system meets the above calculated values. Then, based on the selected printing powder, a laser additive manufacturing experiment is carried out.

[0054] The powder prepared above is used for laser additive manufacturing. Before forming, the powder is placed in a vacuum drying oven and dried at a constant temperature of 70 °C for 8 h in a low-oxygen environment to remove the moisture of the powder and enhance the powder flowability.

[0055] According to the national standard, a standard tensile test sample and a fracture toughness test sample model are established. After slicing with slicing software, a series of stacked slice layers are obtained, and corresponding laser printing strategies are planned for each slice layer. The printing forming parameters are set as follows: laser power 370 W, scanning speed 1100 mm / s, scanning spacing 0.12 mm / s, stripe width 80 μm, stripe offset 0.06 mm, layer thickness 30 μm. A slice data processing file is generated and imported into the laser additive manufacturing equipment.

[0056] The laser additive manufacturing equipment is debugged, and devices such as the substrate and the doctor blade are adjusted to appropriate positions. Argon is introduced into the forming cylinder of the laser additive manufacturing equipment to reduce the oxygen content to below 100 ppm, and a low-oxygen environment is maintained during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter, and there is almost no "black slag" that appears in the traditional Al-Mg-Sc-Zr forming process. After the forming is completed, to ensure safety, the formed sample can be taken out only after standing for at least 6 h. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.9 μm.

[0057] The taken-out part is placed in an air-circulation heat treatment furnace for heat treatment. The heat treatment temperature is 300 °C and the holding time is 2 h. After heat treatment, there are no cracks on the surface of the formed sample, and the mechanical properties are detected.

[0058] The technical solution of the present invention will be described in detail below in conjunction with several embodiments.

[0059] Embodiment 1

[0060] In this embodiment, a high-performance aluminum alloy composition system for additive manufacturing is provided. According to the alloy phase diagram and the solid solution strengthening principle, the Mg and Mn element ratios with better solid solution strengthening effects are calculated. The designed contents of Mg and Mn elements are Mg: 0.8-1.4% and Mn: 4.5-5.5% respectively. Powders are prepared according to the Mg-Mn element ratio, and the contents of other raw material elements are Al ~ the balance, Sc ~ 0.6-0.9%, Zr ~ 0.4-0.7%, O <0.06% and Si <0.2% respectively.

[0061] Using a laboratory true air atomization VIGA equipment, set the atomization temperature at 820 - 850 °C, the atomization pressure at 2.0 - 2.5 MPa, and the diameter of the diversion tube at 4.2 mm. After passivating the atomized powder for 24 hours, screen the powder suitable for the LPBF particle size distribution for laser additive manufacturing experiments. The elemental contents of the prepared powder are Al - the balance, Mg - 1.07%, Mn - 5.15%, Sc - 0.72%, Zr - 0.36%, O - 0.031%, and Si - 0.045% respectively. The elemental contents of the prepared powder are in line with the designed value range.

[0062] The prepared Al-Mg-Mn-Sc-Zr powder has good quality, few satellite powders, high sphericity (89%), a loose bulk density of 1.45 g / cm3, and a tapped density of 1.58 g / cm3. Powder D10 (μm): 18.22, D50 (μm): 35.34, D90 (μm): 62.82. The powder morphology is as Figure 1 shown.

[0063] Use the above-prepared powder for laser additive manufacturing forming. Before forming, place the powder in a vacuum drying oven, keep it at a constant temperature of 70 °C in a low-oxygen environment and dry it for 8 hours to remove the moisture of the powder and enhance the powder flowability.

[0064] Establish the models of standard tensile test samples and fracture toughness test samples according to the national standard, use MagicMaterialise software to complete slicing, the forming parameters are power 370 W, scanning speed 1100 mm / s, scanning spacing 0.12 mm / s, strip width 80 μm, strip offset 0.06 mm, layer thickness 30 μm, and import the sliced file into the forming equipment.

[0065] Debug the forming equipment. After adjusting the substrate, scraper and other devices to the appropriate positions.

[0066] Introduce argon gas into the forming cylinder to reduce the oxygen content to below 100 ppm, and maintain a low-oxygen environment during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter and almost no "black slag" that appears in the traditional Al-Mg-Sc-Zr forming process.

[0067] After the forming is completed, to ensure safety, the formed sample can be taken out only after standing for at least 6 hours. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.9 μm.

[0068] The elemental contents of the prepared specimens are Al - the balance, Mg - 0.87%, Mn - 4.92%, Sc - 0.7%, Zr - 0.4%, O - / , and Si - 0.047%. Among them, the elements Mg and Mn were ablated, and their elemental contents decreased, with Mg showing the most significant decrease.

[0069] The ablation of elements Mg and Mn in the Al - Mg - Mn - Sc - Zr alloy is jointly caused by their vapor pressure characteristics and the high - temperature environment of the molten pool. The vapor pressure of element Mg is relatively high (about 0.001 atm at a temperature of 1090 °C). During the LPBF process, when an extremely high temperature (exceeding the boiling point of the material) is generated in a local area of the laser, Mg is prone to gasification and volatilization. This ablation process will significantly reduce the Mg content in the specimen, thereby weakening the precipitation ability of its strengthening phases (such as Mg2Si), resulting in a decrease in the strength and elongation of the material. Due to its relatively low melting point (1246 °C) and moderate vapor pressure, element Mn is also prone to partial volatilization in a high - temperature environment, thus affecting the corrosion resistance and thermal stability of the formed part. The decrease in the contents of Mg and Mn will change the phase composition inside the alloy and reduce the quantity and distribution uniformity of the strengthening phases. In particular, the reduction of Mg will lead to a weakening of the bonding force between grains and an increase in the sensitivity of crack propagation.

[0070] The removed parts were placed in an air - circulating heat - treatment furnace for heat treatment. The heat - treatment temperature was 300 °C, and the holding time was 2 h. After heat treatment, there were no cracks on the surface of the formed samples, and their mechanical properties were tested. The results were a tensile strength of 515.3 MPa, an elongation of 16.5%, and a fracture toughness (K IC ) of 20.2 MPa·m 1 / 2 .

[0071] Example 2

[0072] In this example, a high - performance aluminum - alloy composition system for additive manufacturing was provided. According to the alloy phase diagram and the solid - solution strengthening principle, the ratio of elements Mg and Mn with better solid - solution strengthening effects was calculated. The designed contents of elements Mg and Mn were Mg: 1.5 - 2.5% and Mn: 3.5 - 4.5% respectively. Powders were prepared according to the Mg - Mn element ratio, and the elemental contents of other raw materials were Al - the balance, Sc - 0.6 - 0.9%, Zr - 0.4 - 0.7%, O < 0.06%, and Si < 0.2%.

[0073] Using a laboratory true air atomization VIGA equipment, set the atomization temperature at 820 - 850 °C, the atomization pressure at 2.0 - 2.5 MPa, and the diameter of the diversion tube at 4.2 mm. After passivating the atomized powder for 24 hours, sieve the powder with a particle size distribution suitable for LPBF for laser additive manufacturing experiments. The elemental contents of the prepared powder are Al - the balance, Mg - 2.04%, Mn - 4.07%, Sc - 0.89%, Zr - 0.51%, O - 0.031%, and Si - 0.037%. The elemental contents of the prepared powder are in line with the designed value range.

[0074] The prepared Al - Mg - Mn - Sc - Zr powder has good quality, few satellite powders, high sphericity (89%), a loose bulk density of 1.45 g / cm3, and a tapped density of 1.58 g / cm3. Powder D10 (μm): 18.22, D50 (μm): 35.34, D90 (μm): 62.82. The powder morphology is as Figure 1 shown.

[0075] Use the above - prepared powder for laser additive manufacturing. Before forming, place the powder in a vacuum drying oven, dry it at a constant temperature of 70 °C for 8 hours while maintaining a low - oxygen environment to remove the moisture of the powder and enhance its fluidity.

[0076] Establish the models of standard tensile test specimens and fracture toughness test specimens according to national standards, use MagicMaterialise software to complete slicing. The forming parameters are power 370 W, scanning speed 1100 mm / s, scanning spacing 0.12 mm / s, stripe width 80 μm, stripe offset 0.06 mm, layer thickness 30 μm, and import the sliced file into the forming equipment.

[0077] Debug the forming equipment. After adjusting the substrate, scraper and other devices to appropriate positions.

[0078] Introduce argon gas into the forming cylinder to reduce the oxygen content to below 100 ppm, and maintain a low - oxygen environment during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter and almost no "black slag" that appears in the traditional Al - Mg - SC - ZR forming process.

[0079] After the forming is completed, to ensure safety, it is necessary to let it stand for at least 6 hours before taking out the formed sample. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.7 μm.

[0080] The elemental contents of the prepared specimens are Al - the balance, Mg - 1.76%, Mn - 4.17%, Sc - 0.93%, Zr - 0.41%, O - / , and Si - 0.047%. Among them, Mg has ablated and the elemental content has decreased significantly.

[0081] The ablation of Mg and Mn elements in the Al-Mg-Mn-Sc-Zr alloy is jointly caused by their vapor pressure characteristics and the high-temperature environment of the molten pool. The vapor pressure of the Mg element is relatively high (about 0.001 atm at a temperature of 1090 °C). During the LPBF process, when an extremely high temperature (exceeding the boiling point of the material) is generated in the local area of the laser, Mg is easily vaporized and volatilized. This ablation process will significantly reduce the Mg content in the sample, thereby weakening the precipitation ability of its strengthening phases (such as Mg2Si), resulting in a decrease in the strength and elongation of the material. Due to its lower melting point (1246 °C) and moderate vapor pressure, the Mn element is also prone to partial volatilization in a high-temperature environment, thus affecting the corrosion resistance and thermal stability of the formed part. The decrease in the content of Mg and Mn will change the phase composition inside the alloy, reducing the quantity and distribution uniformity of the strengthening phases. In particular, the reduction of Mg will lead to a weakening of the bonding force between grains, increasing the sensitivity of crack propagation.

[0082] The removed parts were placed in an air-circulation heat treatment furnace for heat treatment. The heat treatment temperature was 300 °C, and the holding time was 2 h. After heat treatment, there were no cracks on the surface of the formed samples, and the mechanical properties were tested. The results were a tensile strength of 500.8 MPa, an elongation of 16.5%, and the measured fracture toughness K IC = 29.5 MPa·m 1 / 2 .

[0083] Example 3

[0084] In this example, a high-performance aluminum alloy composition system for additive manufacturing was provided. According to the alloy phase diagram and solid solution strengthening principle, the ratio of Mg and Mn elements with better solid solution strengthening effect was calculated. The designed contents of Mg and Mn elements were Mg: 1.5 - 2.5% and Mn: 1.5 - 2.5% respectively. Powders were prepared according to the Mg-Mn element ratio, and the contents of other raw material elements were Al ~ balance, Sc ~ 0.6 - 0.9%, Zr ~ 0.4 - 0.7%, O < 0.06% and Si < 0.2%.

[0085] Using the laboratory vacuum gas atomization VIGA equipment, the atomization temperature was set at 820 - 850 °C, the atomization pressure was 2.0 - 2.5 MPa, and the diameter of the guide pipe was 4.2 mm. After the atomized powder was passivated for 24 h, the powder with a particle size distribution suitable for LPBF was screened for laser additive manufacturing experiments. The element contents of the prepared powder were Al ~ balance, Mg ~ 2.16%, Mn ~ 2.17%, Sc ~ 0.73%, Zr ~ 0.48%, O ~ 0.03% and Si ~ 0.042%. The element contents of the prepared powder were in line with the designed value range.

[0086] The prepared Al-Mg-Mn-Sc-Zr powder has good quality, few satellite powders, high sphericity (89%), a loose bulk density of 1.45 g / cm3, and a tapped density of 1.58 g / cm3. Powder D10 (μm): 18.22, D50 (μm): 35.34, D90 (μm): 62.82. The powder morphology is as Figure 1 shown.

[0087] The above-prepared powder is used for laser additive manufacturing. Before forming, the powder is placed in a vacuum drying oven and dried at a constant temperature of 70 °C for 8 h in a low-oxygen environment to remove the moisture of the powder and enhance the powder flowability.

[0088] According to the national standard, a standard tensile test sample and a fracture toughness test sample model are established. Slicing is completed using MagicMaterialise software. The forming parameters are a power of 370 W, a scanning speed of 1100 mm / s, a scanning spacing of 0.12 mm / s, a stripe width of 80 μm, a stripe offset of 0.06 mm, and a layer thickness of 30 μm. The sliced file is imported into the forming equipment.

[0089] Debug the forming equipment. After adjusting the substrate, scraper and other devices to the appropriate positions.

[0090] Argon is introduced into the forming cylinder to reduce the oxygen content to less than 100 ppm, and a low-oxygen environment is maintained during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter, and almost no "black slag" appears during the traditional Al-Mg-SC-ZR forming process.

[0091] After the forming is completed, to ensure safety, the formed sample can be taken out only after standing for at least 6 h. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.8 μm.

[0092] The element contents of the prepared specimens are Al - the balance, Mg - 1.84%, Mn - 2.12%, Sc - 0.72%, Zr - 0.46%, O - / , and Si - 0.036%. Among them, Mg is ablated and the element content decreases significantly.

[0093] The ablation of Mg and Mn elements in the Al-Mg-Mn-Sc-Zr alloy is jointly caused by their vapor pressure characteristics and the high-temperature environment of the molten pool. The vapor pressure of Mg element is relatively high (about 0.001 atm at 1090 °C). During the LPBF process, when extremely high temperatures (exceeding the boiling point of the material) are generated in the local laser area, Mg is easily vaporized and volatilized. This ablation process will significantly reduce the Mg content in the specimen, thereby weakening the precipitation ability of its strengthening phases (such as Mg2Si), resulting in a decrease in the strength and elongation of the material. Due to its relatively low melting point (1246 °C) and moderate vapor pressure, Mn element is also prone to partial volatilization in a high-temperature environment, thus affecting the corrosion resistance and thermal stability of the formed part. The decrease in the content of Mg and Mn will change the phase composition inside the alloy and reduce the quantity and distribution uniformity of the strengthening phases. In particular, the reduction of Mg will lead to a weakening of the bonding force between grains and an increase in the sensitivity of crack propagation.

[0094] The removed parts were placed in an air-circulation heat treatment furnace for heat treatment. The heat treatment temperature was 300 °C and the holding time was 2 h. After heat treatment, there were no cracks on the surface of the formed samples, and the mechanical properties were tested. The results were as follows: the tensile strength was 506.5 MPa, the elongation was 13.7%, and the fracture toughness (K IC ) was 34.9 MPa·m 1 / 2 . The load-displacement curve of the fracture toughness test is as shown in Figure 8 . Comparing with the load-displacement curve of the specimen with the Mg-Mn content of No. ② in Figure 7 , under the Mg-Mn content of No. ③, the curve is smoother.

[0095] EBSD was used to analyze the failure path of the specimen after fracture with the Mg-Mn content of No. ③. As shown in Figure 9 , it was found that the fracture path under this Mg-Mn content was more tortuous, forming a better crack resistance.

[0096] Example 4

[0097] In this example, a high-performance aluminum alloy composition system for additive manufacturing was provided. According to the alloy phase diagram and the solid solution strengthening principle, the ratio of Mg and Mn elements with better solid solution strengthening effect was calculated. The designed contents of Mg and Mn elements were Mg: 1.5-2.5% and Mn: 1.5-2.5% respectively. Powders were prepared according to the ratio of Mg-Mn elements, and the contents of other raw material elements were Al ~ the balance, Sc ~ 0.6-0.9%, Zr ~ 0.4-0.7%, O < 0.06% and Si < 0.2%.

[0098] Using a laboratory vacuum gas atomization VIGA equipment, set the atomization temperature at 820 - 850 °C, the atomization pressure at 2.0 - 2.5 MPa, and the diameter of the guiding tube at 4.2 mm. After passivating the atomized powder for 24 hours, screen the powder with a particle size distribution suitable for LPBF for laser additive manufacturing experiments. The elemental contents of the prepared powder are Al - the balance, Mg - 2.48%, Mn - 1.61%, Sc - 0.78%, Zr - 0.52%, O - 0.03%, and Si - 0.043%. The elemental contents of the prepared powder are in line with the designed value range.

[0099] The prepared Al-Mg-Mn-Sc-Zr powder has good quality, few satellite powders, a high sphericity (89%), a loose bulk density of 1.45 g / cm3, and a tapped density of 1.58 g / cm3. Powder D10 (μm): 18.39, D50 (μm): 35.75, D90 (μm): 62.12. The powder morphology is as Figure 1 shown.

[0100] Use the above-prepared powder for laser additive manufacturing. Before forming, place the powder in a vacuum drying oven, dry it at a constant temperature of 70 °C for 8 hours in a low-oxygen environment to remove the moisture of the powder and enhance the powder fluidity.

[0101] Establish the models of standard tensile test samples and fracture toughness test samples according to the national standard, use MagicMaterialise software to complete slicing, and the forming parameters are power 370 W, scanning speed 1100 mm / s, scanning spacing 0.12 mm / s, stripe width 80 μm, stripe offset 0.06 mm, layer thickness 30 μm, and import the sliced file into the forming equipment.

[0102] Debug the forming equipment, and adjust devices such as the substrate and the scraper to appropriate positions.

[0103] Introduce argon gas into the forming cylinder to reduce the oxygen content to below 100 ppm, and maintain a low-oxygen environment during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter, and there is almost no "black slag" that appears in the traditional Al-Mg-SC-ZR forming process.

[0104] After the forming is completed, to ensure safety, it is necessary to let it stand for at least 6 hours before taking out the formed sample. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.8 μm.

[0105] The elemental contents of the prepared specimens are Al - the balance, Mg - 2.06%, Mn - 1.21%, Sc - 0.68%, Zr - 0.48%, O - / , and Si - 0.035%. Among them, Mg has undergone ablation, and the elemental content has decreased significantly.

[0106] The ablation of Mg and Mn elements in the Al-Mg-Mn-Sc-Zr alloy is jointly caused by their vapor pressure characteristics and the high-temperature environment of the molten pool. The vapor pressure of the Mg element is relatively high (about 0.001 atm at a temperature of 1090 °C). During the LPBF process, when an extremely high temperature (exceeding the boiling point of the material) is generated in the local area of the laser, Mg is easily vaporized and volatilized. This ablation process will significantly reduce the Mg content in the specimen, thereby weakening the precipitation ability of its strengthening phases (such as Mg2Si), resulting in a decrease in the strength and elongation of the material. Due to its low melting point (1246 °C) and moderate vapor pressure, the Mn element is also easily partially volatilized in a high-temperature environment, thus affecting the corrosion resistance and thermal stability of the formed part. The decrease in the content of Mg and Mn will change the phase composition inside the alloy and reduce the quantity and distribution uniformity of the strengthening phases. In particular, the reduction of Mg will lead to a weakening of the bonding force between grains and an increase in the sensitivity of crack propagation.

[0107] The removed parts were placed in an air-circulation heat treatment furnace for heat treatment. The heat treatment temperature was 300 °C, and the holding time was 2 h. After heat treatment, there were no cracks on the surface of the formed samples, and the mechanical properties were tested. The results were a tensile strength of 509.1 MPa, an elongation of 13.9%, and a fracture toughness (KIC) of 33.8 MPa·m 1 / 2 。

[0108] Example 5

[0109] In this example, a high-performance aluminum alloy composition system for additive manufacturing was provided. According to the alloy phase diagram and the solid solution strengthening principle, the Mg and Mn element ratios with better solid solution strengthening effects were calculated. The designed contents of the Mg and Mn elements were Mg: 1.5 - 2.5% and Mn: 1.5 - 2.5% respectively. Powders were prepared according to the Mg-Mn element ratio, and the contents of other raw material elements were Al ~ the balance, Sc ~ 0.6 - 0.9%, Zr ~ 0.4 - 0.7%, O < 0.06% and Si < 0.2%.

[0110] Using a laboratory vacuum gas atomization VIGA equipment, the atomization temperature was set at 820 - 850 °C, the atomization pressure was 2.0 - 2.5 MPa, and the diameter of the draft tube was 4.2 mm. After the atomized powder was passivated for 24 h, the powder with a particle size distribution suitable for LPBF was screened for laser additive manufacturing experiments. The element contents of the prepared powder were Al ~ the balance, Mg ~ 1.61%, Mn ~ 2.45%, Sc ~ 0.71%, Zr ~ 0.62%, O ~ 0.03% and Si ~ 0.045%. The element contents of the prepared powder were in line with the designed value range.

[0111] The prepared Al-Mg-Mn-Sc-Zr powder has good quality, few satellite powders, high sphericity (89%), a loose bulk density of 1.45 g / cm3, and a tapped density of 1.58 g / cm3. Powder D10 (μm): 18.39, D50 (μm): 35.75, D90 (μm): 62.12. The powder morphology is as Figure 1 shown.

[0112] The above-prepared powder is used for laser additive manufacturing. Before forming, the powder is placed in a vacuum drying oven and dried at a constant temperature of 70 °C for 8 h in a low-oxygen environment to remove the moisture of the powder and enhance the powder flowability.

[0113] According to the national standard, a standard tensile test sample and a fracture toughness test sample model are established. The slicing is completed using MagicMaterialise software. The forming parameters are a power of 370 W, a scanning speed of 1100 mm / s, a scanning spacing of 0.12 mm / s, a stripe width of 80 μm, a stripe offset of 0.06 mm, and a layer thickness of 30 μm. The sliced file is imported into the forming equipment.

[0114] The forming equipment is debugged. After the substrate, scraper and other devices are adjusted to the appropriate positions.

[0115] Argon is introduced into the forming cylinder to reduce the oxygen content to below 100 ppm, and a low-oxygen environment is maintained during the forming process. As Figure 2 shown, during the forming process of this powder, there is less spatter, and there is almost no "black slag" that appears in the traditional Al-Mg-SC-ZR forming process.

[0116] After the forming is completed, to ensure safety, the formed sample can be taken out only after standing for at least 6 h. As Figure 2 shown, the surface of the sample is bright, the surface morphology is good, and the side roughness is only 2.8 μm.

[0117] The element contents of the prepared specimens are Al - the balance, Mg - 1.30%, Mn - 2.02%, Sc - 0.65%, Zr - 0.51%, O - / , and Si - 0.031%. Among them, Mg is ablated and the element content decreases significantly.

[0118] The ablation of Mg and Mn elements in Al-Mg-Mn-Sc-Zr alloy is jointly caused by their vapor pressure characteristics and the high-temperature environment of the molten pool. The vapor pressure of Mg element is relatively high (about 0.001 atm at 1090 °C). During the LPBF process, when the laser locally generates an extremely high temperature (exceeding the boiling point of the material), Mg is easily vaporized and volatilized. This ablation process will significantly reduce the Mg content in the specimen, thereby weakening the precipitation ability of its strengthening phases (such as Mg2Si), resulting in a decrease in the strength and elongation of the material. Due to its relatively low melting point (1246 °C) and moderate vapor pressure, Mn is also prone to partial volatilization in a high-temperature environment, thus affecting the corrosion resistance and thermal stability of the formed part. The decrease in the contents of Mg and Mn will change the phase composition inside the alloy and reduce the quantity and distribution uniformity of the strengthening phases. In particular, the reduction of Mg will lead to a weakening of the bonding force between grains and an increase in the sensitivity of crack propagation.

[0119] The taken-out parts were placed in an air-circulation heat treatment furnace for heat treatment. The heat treatment temperature was 300 °C and the holding time was 2 h. After heat treatment, there were no cracks on the surface of the formed samples, and the mechanical properties were tested. The results were as follows: the tensile strength was 506.2 MPa, the elongation was 14.2%, and the fracture toughness (K IC ) was 34.3 MPa·m 1 / 2 .

[0120] In Examples 3, 4, and 5, the powder contents of Mg and Mn elements were both ③ Mg: 1.5 - 2.5%, Mn: 1.5 - 2.5%. In this powder ratio range, the tensile strength of the specimen remained at 505 - 510 MPa, the elongation remained at 13 - 15%, and the fracture toughness (K IC ) remained at 33 - 35 MPa·m 1 / 2 , and the performance was relatively stable, as Figure 10 shown.

Claims

1. A high-performance aluminum alloy composition system for additive manufacturing, characterized in that: In terms of mass percentage, it includes: Mg: 0.8%-2.5%, Mn: 1.5-5.5%, Sc: 0.6-0.8%, Zr: 0.4-0.7%, O<0.06% and Si<0.2%, and the rest is Al.

2. The high-performance aluminum alloy composition system for additive manufacturing according to claim 1, characterized in that: The Mg content is: 0.8-1.4%, and the Mn content is: 4.5-5.5%.

3. The high-performance aluminum alloy composition system for additive manufacturing according to claim 1, characterized in that: The Mg content is: 1.5-2.5%, and the Mn content is: 3.5-4.5%.

4. The high-performance aluminum alloy composition system for additive manufacturing according to claim 1, characterized in that: The Mg content is: 1.5-2.5%, and the Mn content is: 1.5-2.5%.

5. A method for preparing a powder of a high-performance aluminum alloy component system for additive manufacturing, characterized in that: The steps include: Step 1: Design the distribution ratio of each component of the high-performance aluminum alloy composition system: The components of the high-performance aluminum alloy composition system include Mg, Mn, Sc, Zr, O, Si and Al; Based on the alloy phase diagram and the principle of solid solution strengthening, the ratio of Mg and Mn elements with better solid solution strengthening effect is calculated and meets the following requirements: y=-15.6261x 5 +111.1631x 4 -312.7712x 3 +434.5672x 2 -298.2785x+86.1335; Wherein: y is the mass content of the Mn element in the high-performance aluminum alloy composition system, and its value is 1.5-5.5%; x is the mass content of the Mg element in the high-performance aluminum alloy composition system, and its value is 0.8%-2.5%; Based on the calculated Mg-Mn element ratio, the other components are powdered separately, and the mass content of the other components is: Sc: 0.6-0.8%, Zr: 0.4-0.7%, O<0.06% and Si<0.2%, the rest is Al; Step 2: Prepare the printing powder system: A high-performance aluminum alloy component system is prepared according to the distribution ratio of each group of the high-performance aluminum alloy component system designed in step one, and then subjected to atomization, passivation, screening and drying treatments in sequence to obtain a printing powder system suitable for additive manufacturing. The distribution ratio of each group in the obtained printing powder system needs to meet the distribution ratio of each group of the high-performance aluminum alloy component system designed in step one.

6. The method for preparing powder of a high-performance aluminum alloy component system for additive manufacturing according to claim 5, characterized in that: In step 2, vacuum atomization equipment is used for atomization, and the atomization process parameters are: setting the atomization temperature to 820-850°C, the atomization pressure to 2.0-2.5MPa, and the guide tube diameter to 4.2mm.

7. The method for preparing powder of a high-performance aluminum alloy component system for additive manufacturing according to claim 5, characterized in that: In the high-performance aluminum alloy component system prepared in step 1, the Mg content is: 0.8-1.4%, and the Mn content is: 4.5-5.5%; Or in the high-performance aluminum alloy component system prepared in step 1, the Mg content is: 1.5-2.5%, and the Mn content is: 3.5-4.5%; or in the high-performance aluminum alloy component system prepared in step 1, the Mg content is: 1.5-2.5%, and the Mn content is: 1.5-2.5%.

8. A laser additive manufacturing method for high-performance aluminum alloy components, characterized in that: The steps include: Step A: Preparation of printing powder system: The printing powder system is made based on the powder preparation method of the high-performance aluminum alloy component system for additive manufacturing as described in claim 5; Step B: Laser additive manufacturing of high-performance aluminum alloy components: Step B.1, using 3D modeling software to establish a 3D solid geometric model of a high-performance aluminum alloy component, and using slicing software to slice and layer the established 3D solid geometric model to obtain a series of slice layers stacked layer by layer, and planning a corresponding laser printing strategy for each slice layer, setting printing forming parameters: laser power 370W, scanning speed 1100mm / s, scanning spacing 0.12mm / s, strip width 80μm, strip offset 0.06mm, layer thickness 30μm, generating a slice data processing file, and importing the slice data processing file into the laser additive manufacturing forming equipment; Step B.2, debugging laser additive manufacturing forming equipment; Step B.3, introducing argon gas into the forming cylinder of the laser additive manufacturing forming equipment, and ensuring that the forming cylinder can always maintain a low oxygen environment during the forming process; The high-performance aluminum alloy component system after the drying treatment in step 4 is loaded into the powder cylinder; Step B.4, under the control of the slice data processing file, laser melting each slice layer layer by layer on the substrate of the laser additive manufacturing forming device until all slice layers are laser melted and solidified; Step B.5: After the forming is completed, the formed component is taken out after being left to stand for a period of time and subjected to heat treatment.

9. The laser additive manufacturing method for a high-performance aluminum alloy component according to claim 8, characterized in that: In step B.5, the process parameters of the heat treatment are: holding temperature 300° C., holding time 2 h.

10. The laser additive manufacturing method for a high-performance aluminum alloy component according to claim 8, characterized in that: In step B.3, the oxygen content of the low oxygen environment is less than 100 ppm.

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