Heat-resistant aluminum-based composite material powder for additive manufacturing and preparation method of heat-resistant aluminum-based composite material powder

Abstract

The invention discloses heat-resistant aluminum-based composite material powder for additive manufacturing and a preparation method of the heat-resistant aluminum-based composite material powder for additive manufacturing, and the matrix of the heat-resistant aluminum-based composite material powder for additive manufacturing is Al-TM-Si alloy system powder; tM is one or more of transition group metals; the mass fraction of each component element is as follows: 5%-15% of TM, 0.5%-2.5% of Si and the balance of Al. The transition group metal is at least one of Sc, Fe, Ti, Ni, Cu, Cr, Co, Zn and V. According to the prepared heat-resistant aluminum-based composite material powder for additive manufacturing, an aluminum-based composite material block printed through a laser powder bed melting technology has the advantages of no crack, high density, good formability and high-temperature tensile property.

Description

Technical Field

[0001] This invention relates to the field of heat-resistant aluminum alloy material preparation, and in particular to a heat-resistant aluminum-based composite powder for additive manufacturing and its preparation method. Background Technology

[0002] Aluminum alloys, due to their low density, high specific strength, good corrosion resistance, and excellent processing performance, are widely used in aerospace, automotive manufacturing, construction engineering, electronic equipment, and many other fields. However, because aluminum alloys have low melting points and high stacking fault energies, they are prone to recovery and recrystallization. Furthermore, the dispersed precipitates in most age-hardened aluminum alloys undergo rapid coarsening or dissolution above 200℃, making it difficult for most aluminum alloys to be used long-term above 200℃. In recent years, increasingly demanding high-temperature service environments have placed higher requirements on the heat resistance of aluminum alloys, thus urgently requiring the development of heat-resistant aluminum alloy materials that can be used for extended periods at higher temperatures. Adding ceramic reinforcing phases (such as TiC, SiC, AlN, TiB2, Y2O3, etc.) to the aluminum matrix is ​​one of the effective ways to improve its heat resistance. The stress field induced by lattice distortion between the ceramic particle reinforcing phase and the matrix can affect the distribution and migration of precipitates in the alloy, and during high-temperature deformation, it acts as a grain boundary pinner, hindering dislocation movement, thus contributing to improved microstructure thermal stability and high-temperature mechanical properties.

[0003] Laser powder bed fusion (LBD) is a core technology in additive manufacturing (also known as 3D printing). Its principle involves selectively melting metal powder layer by layer using a high-energy laser beam, achieving ordered stacking of metal or alloy powders to create near-net-shape parts with complex structures. This process eliminates the need for molds, resulting in high material utilization and the ability to recycle unmelted powder. LBD technology allows for precise control of the microstructure of aluminum alloys, achieving superior comprehensive properties unattainable by conventional casting and powder metallurgy. In the additive manufacturing of heat-resistant aluminum alloys, the heat resistance of the alloys can be improved by controlling the powder composition. Currently, the ceramic-reinforced aluminum matrix composite materials used in LBD technology often rely on the mechanical mixing of aluminum alloy powders and nano-ceramic particles.

[0004] In summary, due to the high surface energy of nanoscale particles, they are prone to aggregation, and their distribution and morphology are difficult to control. Therefore, through mechanical mixing, nano-ceramic particles can only adhere to the surface of the matrix particles and cannot exist inside the matrix particles. This non-uniformity in the distribution of ceramic reinforcing phase particles can easily cause excessive local thermal stress during 3D printing, leading to cracks and severely affecting the formability and mechanical properties of additively manufactured aluminum-based composite materials.

[0005] To address the problems of the existing technology mentioned above: This invention provides a heat-resistant aluminum-based composite material powder for additive manufacturing and its preparation method. The composite material powder prepared by the above method is used to print aluminum-based composite material blocks without cracks, with high density, good formability, and significantly improved high-temperature tensile properties through laser powder bed melting technology.

[0006] More specifically: This invention yields an aluminum-based composite material with excellent high-temperature performance. It involves hot-pressing and sintering a mechanically homogenized Al-TM-Si mixture (TM being a transition metal element) and nano-ceramic particles into a dense bulk. The dense bulk is then decomposed into nano-ceramic particle-reinforced aluminum-based composite powder using an atomization method. This achieves uniform dispersion of ceramic particles within and on the surface of the matrix particles, resulting in a composite powder with uniform size, good sphericity, and good flowability. Further analysis and testing show that the aluminum-based composite material block printed using laser powder bed melting technology is crack-free, has high density, good formability, and significantly improved high-temperature tensile properties. Summary of the Invention

[0007] The purpose of this invention is to provide a heat-resistant aluminum-based composite material powder for additive manufacturing and its preparation method. The heat-resistant aluminum-based composite material powder for additive manufacturing prepared by the above-mentioned formulation and process can produce aluminum-based composite material blocks that are crack-free, have high density, good formability, and good high-temperature tensile properties when printed by laser powder bed melting technology.

[0008] To achieve the above objectives, the following technical solutions are used: A heat-resistant aluminum-based composite powder for additive manufacturing. The matrix is ​​an Al-TM-Si alloy system powder; TM represents one or more transition metals; The mass fractions of each constituent element are as follows: TM: 5%-15%, Si: 0.5-2.5%, and the remainder is Al.

[0009] As a further preferred option, the transition metal is at least one selected from Sc, Fe, Ti, Ni, Cu, Cr, Co, Zn, and V.

[0010] As a further preferred option, the added nanoparticle reinforcing phase is at least one of TiC, TiB2, Y2O3, SiC, and AlN; The mass fraction of ceramic particles ranges from 1% to 5%.

[0011] As a further preferred option, the average particle size of Al-TM-Si powder is 1-5 µm; The average particle size of the ceramic powder is 50-300 nm.

[0012] A method for preparing the heat-resistant aluminum-based composite powder for additive manufacturing includes the following preparation steps: S1: Weigh the Al-TM-Si alloy powder and nano-ceramic powder according to the mass fraction and then mechanically mix them in a mixer; S2: The mechanically mixed Al-TM-Si alloy powder and ceramic powder are dried and then hot-pressed and sintered to form a dense alloy block. S3: The dense alloy block obtained by hot pressing and sintering is placed in a melting device for atomization and powdering. S4: The powder obtained by atomization in step S3 is classified and dried to obtain nano-ceramic particle reinforced aluminum matrix composite powder for additive manufacturing.

[0013] S5: The aluminum-based composite material powder obtained in step S4 is used for bulk printing and performance verification using laser powder bed melting technology.

[0014] As a further preferred option, the mixing time in S1 is 12-24 hours, and the drying time is 12-24 hours, which is carried out in a vacuum drying oven; The hot pressing pressure in S2 is 20-40 MPa, the temperature is 300-600℃, the heating rate is 80-100℃ / min, the sintering time is 1-3 hours, and the vacuum degree is less than 10-3 Pa. As a further preferred option, in S3, when the vacuum degree is lower than 10⁻³ Pa, the preset temperature range is 800~1000℃.

[0015] In S3, when the vacuum level reaches below the preset vacuum level, an inert gas is introduced to atmospheric pressure. The inert gas is high-purity argon or nitrogen, and the gas flow rate is controlled at 10-200 L / min, with a gas atomization pressure of 4-10 MPa.

[0016] As a further preferred option, the ceramic-reinforced aluminum matrix composite powder obtained in S4 is dried and then sieved, with an average particle size of 15-53 μm.

[0017] As a further preferred option, the laser powder bed melting technology described in S5 has an energy density of 50~80 J / mm². 3 The laser power is between 190 and 350W, and the scanning speed is between 1000 and 2000 mm / s.

[0018] As a further preferred option, in S5, the oxygen content is controlled below 0.200%; The substrate temperature is set to 120-180 ℃, and the layer thickness is set to 20 µm~40 µm.

[0019] The present invention provides a heat-resistant aluminum-based composite material powder for additive manufacturing and a method for preparing the same, which has the following beneficial effects: 1) The heat-resistant aluminum-based composite powder of the present invention is prepared by adding a certain proportion of nano-ceramic particles as Al-TM-Si alloy as matrix, and is used in the additive manufacturing field of high-strength heat-resistant aluminum-based composite materials.

[0020] 2) The heat-resistant aluminum-based composite material of the present invention is hot-pressed and sintered, then atomized (which enables uniform dispersion of ceramic particles in the aluminum matrix, not only on the surface of the matrix particles but also inside the matrix particles, such as...). Figure 1 The diagram shown illustrates the preparation of ceramic particle-reinforced heat-resistant aluminum matrix composite powder in this invention. The resulting powder is: More specifically, ceramic-reinforced aluminum matrix composite powder is prepared by mechanical mixing in the early stage and then hot pressing and sintering of the powder, with ceramic particles only distributed on the surface of the matrix particles; 3) During the laser powder bed melting process, the heat-resistant aluminum-based composite powder of the present invention will generate a nano-reinforcing phase with extremely small size due to rapid cooling, such as Al12(Fe,V)3Si phase, etc. The reinforcing phase is uniformly dispersed in the α-Al solid solution matrix, can form a low interfacial energy coherent interface with the matrix, and has a low coarsening rate, which is a heat-resistant reinforcing phase. Ceramic particles have been introduced into the heat-resistant aluminum-based composite powder system. Ceramic particles typically possess characteristics such as high hardness, high elastic modulus, and high melting point. Uniformly distributed ceramic particles can significantly alter the solidification path of the matrix and compound, and as heterogeneous nucleating agents, they can refine grains. Simultaneously, they can significantly improve the distribution of thermal stress during rapid solidification, effectively suppressing the generation of hot cracks, thereby enhancing the alloy's formability and heat resistance.

[0021] 4) The heat-resistant aluminum-based composite material for additive manufacturing of the present invention is prepared by using processes such as hot isostatic pressing and atomization powdering to produce ceramic particle-reinforced aluminum-based composite material powder, thereby achieving uniform distribution of ceramic particles in the aluminum matrix. The bulk aluminum-based composite material printed using this powder has excellent high-temperature mechanical properties (the high-temperature tensile strength of the heat-resistant aluminum alloy material at 300℃ is above 250MPa, and the elongation is 3.5%; the high-temperature tensile strength at 350℃ can still be maintained above 200MPa). Based on the above properties, it can be widely used in aerospace, transportation and other fields. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the preparation of the ceramic particle-reinforced heat-resistant aluminum matrix composite powder of the present invention; Figure 2This is a flowchart illustrating the preparation process and printing verification process of the heat-resistant aluminum-based composite material powder in Example 1 of the heat-resistant aluminum-based composite material powder preparation method of the present invention. Figure 3 Microstructure and cross-sectional morphology of aluminum-based composite powder (Al-5.65%Fe-0.76%V-0.94%Si / 2.00%TiC) in Example 1 of this invention.

[0023] Figure 4 EBSD-IPF image of the cross-sectional microstructure of aluminum-based composite powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) in Example 1.

[0024] Figure 5 The morphology and physical image of the printed heat-resistant aluminum-based composite material in Embodiment 1 of the present invention.

[0025] Figure 6 EBSD-IPF image of the microstructure of the heat-resistant aluminum-based composite material in the printed state in Example 1 of this invention.

[0026] Figure 7 High-temperature tensile curve of the printed aluminum-based composite material in Embodiment 1 of the present invention.

[0027] Figure 8 Morphology of the printed heat-resistant aluminum-based composite material in Example 2 and Comparative Example 3 of the present invention.

[0028] Figure 9 The morphology and physical image of the printed aluminum-based composite material in Comparative Example 1 of this invention are shown.

[0029] Figure 10 The morphology diagram and the actual printed aluminum alloy material in Comparative Example 2 of this invention are shown.

[0030] Figure 11 Morphology of the aluminum-based composite material powder prepared in Comparative Example 4 of this invention.

[0031] Figure 12 Metallographic image of the printed aluminum alloy material in Comparative Example 4 of this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below in conjunction with embodiments and accompanying drawings: It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] Unless otherwise specified, the experimental or testing methods described in the embodiments of this invention are all conventional methods; unless otherwise specified, the reagents and / or materials are obtained from conventional commercial sources or prepared by conventional methods.

[0034] Example 1: An aluminum alloy composite powder (which can be used in additive manufacturing) is prepared as follows: Step 1) Mixing Al-5.5Fe-0.6V-1.1Si (mass fraction wt.%) alloy (FVS0611) powder with TiC ceramic powder Al-5.5Fe-0.6V-1.1Si alloy (FVS0611) powder and 2 wt.% TiC ceramic powder were weighed and mixed in a certain proportion, and the mixture was denoted as Al-5.5Fe-0.6V-1.1Si / 2TiC. The average particle size of TiC was 100 nm.

[0035] The mixing process is completed inside the mixer, and the mixing time is 12 hours. Step 2) Dry the mechanically mixed Al-5.5Fe-0.6V-1.1Si / 2TiC powder in a vacuum oven at 80°C for 24 hours. Step 3) The dried Al-5.5Fe-0.6V-1.1Si / 2TiC powder is placed in a hot press furnace and vacuum sintered into a dense alloy block at a vacuum degree of 10. -3 Pa, temperature 550℃, sintering time 1.5 hours; Step 4) Place the hot-pressed and sintered dense alloy block into an atomizing melting device. When the vacuum degree reaches the preset vacuum degree of 10... -3 When the pressure is below Pa, argon gas is introduced to atmospheric pressure, with a preset temperature of 900℃, and then increased to the preset temperature at a rate of 10℃ / min. The melt is then melted into an alloy liquid at the preset melting temperature, flowing through a guide tube into an atomizing nozzle. High-purity argon gas is used as the atomizing medium, spraying and breaking the liquid into fine droplets, which solidify to form the original powder. The argon gas flow rate is 20 L / min, and the gas atomization pressure is 4.5 MPa.

[0036] Step 5) The original powder is classified and sieved to obtain aluminum-based composite material powder with a particle size of 15~53µm; Step 6) Dry the sieved aluminum-based composite powder at 80°C for 12 hours. Step 7) Powder is spread using a laser powder bed fusion device, followed by printing. A unidirectional scanning strategy is employed, with a powder layer thickness of 30 µm, laser power of 260W, scanning speed of 1400 mm / s, scanning spacing of 90 µm, angle increment of 67°, and area overlap set to 0.13 mm. Argon gas is used for protection during the printing process, with an oxygen content ≤0.200%. The substrate preheating temperature during printing is 170°C. After printing, the substrate is removed after cooling to room temperature.

[0037] like Figures 2-7 As shown: Figure 2 This is a flowchart illustrating the powder preparation and printing verification process of ceramic particle-reinforced heat-resistant aluminum matrix composite material in Example 1. Figure 3 The images show the microstructure and cross-sectional morphology of the alloy powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) prepared in Example 1.

[0038] Depend on Figure 2 and Figure 3 It can be seen that the aluminum-based composite powder prepared in Example 1 has good sphericity and uniformly distributed TiC ceramic particles inside the particles. The combination of the formula and process in Example 1 of this invention can effectively achieve the uniform distribution of nano-ceramic particles in the aluminum matrix.

[0039] Figure 4 The image shows the EBSD-IPF plot of the particle cross-section of the alloy powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) in Example 1. Figure 4 It is known that the average particle size of the alloy powder in Example 1 is 2.69 µm.

[0040] Figure 5 The attached image shows the morphology of the printed aluminum-based composite material in Example 1. It can be seen that there is a clear molten pool boundary. The attached image is a photograph of the printed object. It can be seen that the aluminum-based composite material powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) prepared in Example 1 of this invention has good formability and no cracks are generated. Figure 6 The image shows the EBSD orientation distribution of the printed aluminum-based composite material in Example 1. It can be seen that after adding ceramic particles, the printed sample exhibits an equiaxed grain distribution with small grain size, averaging 4.35 µm. Figure 7 The high-temperature tensile curve of the aluminum-based composite material printed in Example 1 shows that the high-temperature tensile strength of the printed heat-resistant aluminum alloy material at 300℃ is above 250MPa and the elongation is 3.5%. The high-temperature tensile strength at 350℃ can still be maintained above 200MPa.

[0041] like Figures 2-7 As shown: Figure 2 This is a flowchart illustrating the powder preparation and printing verification process of ceramic particle-reinforced heat-resistant aluminum matrix composite material in Example 1. Figure 3 The images show the microstructure and cross-sectional morphology of the alloy powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) prepared in Example 1.

[0042] Depend on Figure 2 and Figure 3 It can be seen that the aluminum-based composite powder prepared in Example 1 has good sphericity and uniformly distributed TiC ceramic particles inside the particles. The combination of the formula and process in Example 1 of this invention can effectively achieve the uniform distribution of nano-ceramic particles in the aluminum matrix.

[0043] Figure 4 The image shows the EBSD-IPF plot of the particle cross-section of the alloy powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) in Example 1. Figure 4 It is known that the average particle size of the alloy powder in Example 1 is 2.69 µm.

[0044] Figure 5 The attached image shows the morphology of the printed aluminum-based composite material in Example 1. It can be seen that there is a clear molten pool boundary. The attached image is a photograph of the printed object. It can be seen that the aluminum-based composite material powder (Al-5.5Fe-0.6V-1.1Si / 2TiC) prepared in Example 1 of this invention has good formability and no cracks are generated. Figure 6 The image shows the EBSD orientation distribution of the printed aluminum-based composite material in Example 1. It can be seen that after adding ceramic particles, the printed sample exhibits an equiaxed grain distribution with small grain size, averaging 4.35 µm. Figure 7 The high-temperature tensile curve of the aluminum-based composite material printed in Example 1 shows that the high-temperature tensile strength of the printed heat-resistant aluminum alloy material at 300℃ is above 250MPa and the elongation is 3.5%. The high-temperature tensile strength at 350℃ can still be maintained above 200MPa.

[0045] Example 2: An aluminum alloy composite powder (which can be used in additive manufacturing) is prepared as follows: Step 1) Mixing Al-8.5Fe-1.3V-1.7Si (wt.%) alloy (FVS0812) powder with TiB2 ceramic powder Al-8.5Fe-1.3V-1.7Si alloy powder (FVS0812) was weighed and mixed with 1.00% TiB2 ceramic powder according to a certain ratio, denoted as Al-8.5Fe-1.3V-1.7Si / 1TiB2. The average particle size of TiB2 was 80 nm. The mixing process is completed inside the mixer, and the mixing time is 12 hours. Step 2) Dry the mechanically mixed Al-8.5Fe-1.3V-1.7Si / 1TiB2 powder in a vacuum oven at 80°C for 24 hours. Step 3) The dried Al-8.5Fe-1.3V-1.7Si / 1TiB2 powder is placed in a hot press furnace and vacuum sintered into a dense alloy block at a vacuum degree of 10. -3 Pa, temperature 600℃, sintering time 2 hours; Step 4) Place the hot-pressed and sintered dense alloy block into an atomizing melting device. When the vacuum degree reaches the preset vacuum degree of 10... -3 When the pressure is below Pa, argon gas is introduced to atmospheric pressure, with a preset temperature of 900℃, and then increased to the preset temperature at a rate of 10℃ / min. The melt is then melted into an alloy liquid at the preset melting temperature, flowing through a guide tube into an atomizing nozzle. High-purity argon gas is used as the atomizing medium, spraying and breaking the liquid into fine droplets, which solidify to form the original powder. The argon gas flow rate is 20 L / min, and the gas atomization pressure is 4.5 MPa.

[0046] Step 5) The original powder is classified and sieved to obtain aluminum-based composite material powder with a particle size of 15~53µm; Step 6) Dry the sieved aluminum-based composite powder at 80°C for 12 hours. Step 7) Powder is spread using a laser powder bed fusion device, followed by printing. A unidirectional scanning strategy is employed, with a powder layer thickness of 40 µm, laser power of 280W, scanning speed of 1400 mm / s, scanning spacing of 90 µm, angle increment of 67°, and area overlap set to 0.13 mm. Argon gas is used for protection during the printing process, with an oxygen content ≤0.200%. The substrate preheating temperature during printing is 180°C. After printing, the substrate is removed after cooling to room temperature.

[0047] Figure 8 This is a phase diagram of the printed aluminum-based composite material in Example 2. The addition of TiB2 (Al-8.5Fe-1.3V-1.7Si / 1TiB2) resulted in better formability and no crack formation. Figure 8 As shown in (b); Comparative Example 1: An aluminum alloy composite powder (which can be used in additive manufacturing) is prepared as follows: Step 1) Weigh Al-5.5Fe-0.6V-1.1Si powder and TiC ceramic powder in a certain proportion and mix them. The mass fraction of TiC is 2.00%. The mixing process is completed in a mixer and the mixing time is 12 hours. Step 2) Dry the mechanically mixed Al-5.5Fe-0.6V-1.1Si / 2TiC powder in a vacuum oven at 80°C for 24 hours. Step 3) Powder is spread using a laser powder bed fusion device, followed by shaping. A unidirectional scanning strategy is employed, with a powder layer thickness of 30µm, laser power of 260W, scanning speed of 1400mm / s, scanning spacing of 90µm, angle increment of 67°, and area overlap set to 0.13mm. Argon gas is used for protection during the shaping process, with an oxygen content ≤0.200%. The substrate is preheated to 170℃ during shaping. The substrate is then removed after cooling.

[0048] Comparative Example 1 omits steps S3-S6 of Example 1 and directly performs additive manufacturing after drying the mechanically mixed powder.

[0049] Figure 8 The images show the morphology of the printed aluminum-based composite material and photographs of the printed material in Comparative Example 1.

[0050] like Figure 8 As shown, obvious cracks appear in the printed bulk material, indicating that the uneven distribution of the ceramic reinforcing phase can lead to stress concentration, causing cracking and affecting the final formability and mechanical properties.

[0051] Comparative Example 2: For TiC-free ceramic particles with added Al-5.5Fe-0.6V-1.1Si, direct printing was performed using the same parameters as in Example 1: a unidirectional scanning strategy, a powder layer thickness of 30µm, a laser power of 260W, a scanning speed of 1400mm / s, a scanning spacing of 90µm, an angle increment of 67°, and a region overlap of 0.13mm. Argon gas was used for protection during the printing process, with an oxygen content ≤0.200%. The substrate preheating temperature was 170℃ during printing. After printing, the substrate was cooled and removed.

[0052] Metallographic characterization and photographs of the printed specimens show that the Al-5.5Fe-0.6V-1.1Si / 2TiC printing without TiC ceramic particle reinforcement exhibits obvious cracks, such as... Figure 9 As shown, without the addition of a ceramic reinforcing phase, rapid cooling during the printing process can easily cause microscopic thermal stress, which also affects printability and mechanical properties.

[0053] Therefore, comparing Example 1 and Comparative Example 2, it can be seen that the addition of TiC ceramic particles plays a key role in improving the printability and heat resistance of Al-5.5Fe-0.6V-1.1Si / 2TiC.

[0054] Comparative Example 3: For TiB2-free ceramic particles with added Al-8.5Fe-1.3V-1.7Si, direct printing was performed using the same parameters as in Example 1: a unidirectional scanning strategy, a powder layer thickness of 40µm, a laser power of 280W, a scanning speed of 1400mm / s, a scanning spacing of 90µm, an angle increment of 67°, and a region overlap of 0.13mm. Argon gas was used for protection during the printing process, with an oxygen content ≤0.200%. The substrate preheating temperature was 170℃ during printing. After printing, the substrate was cooled and removed.

[0055] Metallographic characterization and photographs of the printed specimens show that obvious cracks appear in the Al-8.5Fe-1.3V-1.7Si printed specimens without TiB2 ceramic particle reinforcement. Figure 8 As shown in (a), this illustrates that without the addition of a ceramic reinforcing phase, rapid cooling during the printing process can easily cause microscopic thermal stress, which also affects printability and mechanical properties.

[0056] Therefore, comparing Example 2 and Comparative Example 3, it can be seen that, in addition to TiC ceramic particles, the addition of TiB2 ceramic particles also plays a key role in improving the printability and heat resistance of Al-8.5Fe-1.3V-1.7Si.

[0057] Comparative Example 4: An aluminum alloy composite powder (suitable for additive manufacturing), the preparation process of which is as follows: Step 1) Mixing Al-6Fe-1V-1Si alloy (FVS0611) powder with TiC ceramic powder Al-6Fe-1V-1Si alloy (FVS0611) powder and TiC ceramic powder with a mass fraction of 2% were weighed and mixed in a certain proportion, and the mixture was recorded as Al-5.5Fe-0.6V-1.1Si / 2TiC. The average particle size of TiC was 100 nm. The mixing process is completed inside the mixer, and the mixing time is 12 hours. Step 2) Dry the mechanically mixed Al-5.5Fe-0.6V-1.1Si / 2TiC powder in a vacuum oven at 80°C for 24 hours. Step 3) Place the dried mixed powder into an atomizing melting device. When the vacuum level reaches below the preset vacuum level of 10⁻³ Pa, introduce argon gas to atmospheric pressure. The preset temperature is 900℃, and then the temperature is increased to the preset temperature at a rate of 10℃ / min. At the preset melting temperature, the melt is melted into an alloy liquid, which flows into the atomizing nozzle through a guide tube. High-purity argon gas is used as the atomizing medium, which sprays and breaks the mixture into fine droplets, which then solidify to form the original powder. The argon gas flow rate is 20 L / min, and the gas atomization pressure is 4.5 MPa.

[0058] Step 4) The original powder is classified and sieved to obtain aluminum-based composite material powder with a particle size of 15~53µm; Step 5) Dry the sieved aluminum-based composite powder at 80°C for 12 hours. Step 6) Powder is spread using a laser powder bed fusion device, followed by printing. A unidirectional scanning strategy is employed, with a powder layer thickness of 30 µm, laser power of 260W, scanning speed of 1400 mm / s, scanning spacing of 90 µm, angle increment of 67°, and area overlap set to 0.13 mm. Argon gas is used for protection during the printing process, with an oxygen content ≤0.200%. The substrate preheating temperature during printing is 170°C. After printing, the substrate is removed after cooling to room temperature.

[0059] Microstructural observation of the prepared powder revealed that when the mechanically mixed Al-5.5Fe-0.6V-1.1Si / 2TiC powder was directly atomized without hot pressing and sintering, most of the nano-ceramic particles were distributed on the particle surface, making it difficult to achieve uniform distribution within the particles. Figure 11 As shown in the image. Holes appear after printing, as shown below. Figure 12 As shown, the uneven distribution of ceramic particles in aluminum alloys can easily lead to localized compositional inhomogeneity. During the rapid cooling process of printing, different regions experience varying degrees of shrinkage, resulting in porosity. Porosity acts as a crack propagation source, significantly reducing mechanical properties.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A heat-resistant aluminum-based composite powder for additive manufacturing, characterized in that, The matrix is ​​an Al-TM-Si alloy system powder; TM represents one or more transition metals; The mass fractions of each constituent element are as follows: TM: 5%-12%, Si: 0.5-2.0%, and the remainder is Al.

2. The heat-resistant aluminum-based composite powder for additive manufacturing according to claim 1, characterized in that, The transition metal is at least one selected from Sc, Fe, Ti, Ni, Cu, Cr, Co, Zn, and V.

3. The heat-resistant aluminum-based composite powder for additive manufacturing according to claim 1, characterized in that: The added nanoparticle reinforcing phase is at least one of TiC, TiB2, Y2O3, SiC, and AlN; The mass fraction of ceramic particles ranges from 1% to 5%.

4. The heat-resistant aluminum-based composite powder for additive manufacturing according to claim 1, characterized in that: The average particle size of Al-TM-Si powder is 1-5 µm; The average particle size of the ceramic powder is 50-300 nm.

5. A method for preparing the heat-resistant aluminum-based composite powder for additive manufacturing as described in any one of claims 1 to 4, characterized in that, The preparation steps include the following: S1: Weigh the Al-TM-Si alloy powder and nano-ceramic powder according to the mass fraction and then mechanically mix them in a mixer; S2: The mechanically mixed Al-TM-Si alloy powder and ceramic powder are dried and then hot-pressed and sintered to form a dense alloy block. S3: The dense alloy block obtained by hot pressing and sintering is placed in a melting device for atomization and powdering; S4: The powder obtained by atomization in step S3 is classified and dried to obtain nano-ceramic particle reinforced aluminum matrix composite material powder for additive manufacturing. S5: The aluminum-based composite material powder obtained in step S4 is used for bulk printing and performance verification using laser powder bed melting technology.

6. The method for preparing heat-resistant aluminum-based composite powder for additive manufacturing according to claim 5, characterized in that, The mixing time in S1 is 12-24 hours, and the drying time is 12-24 hours, which is carried out in a vacuum drying oven; The hot pressing pressure in S2 is 20~40 MPa, the temperature is 300~600℃, the heating rate is 80~100℃ / min, the sintering time is 1~3 hours, and the vacuum degree is less than 10~3 Pa; 7. The method for preparing heat-resistant aluminum-based composite powder for additive manufacturing according to claim 5, characterized in that, In S3, when the vacuum degree is lower than 10~3Pa, the preset temperature range is 800~1000℃. In S3, when the vacuum level reaches below the preset vacuum level, an inert gas is introduced to atmospheric pressure. The inert gas is high-purity argon or nitrogen, and the gas flow rate is controlled at 10~200 L / min, with a gas atomization pressure of 4~10 MPa.

8. The method for preparing heat-resistant aluminum-based composite powder for additive manufacturing according to claim 5, characterized in that, The ceramic-reinforced aluminum matrix composite powder obtained in S4 was dried and then sieved. The average particle size of the aluminum matrix composite powder was 15~53 μm.

9. The method for preparing heat-resistant aluminum-based composite powder for additive manufacturing according to claim 5, characterized in that, The laser powder bed melting technology described in S5 has an energy density between 50 and 80 J / mm3, a laser power between 190 and 350 W, and a scanning speed between 1000 and 2000 mm / s.

10. The method for preparing heat-resistant aluminum-based composite powder for additive manufacturing according to claim 5, characterized in that, In S5, the oxygen content is controlled below 0.200%; The substrate temperature is set to 120~180 ℃, and the layer thickness is set to 20 µm~40 µm.

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