A method for preparing Ti / Mg composite material powder for 3D printing

Abstract

The application belongs to the field of metal materials, and specifically discloses a preparation method of Ti / Mg composite material powder for 3D printing; the preparation method of the Ti / Mg composite material powder comprises the following steps: mixing titanium powder and a magnesium source, and then sequentially performing ultrasonic dispersion and grinding to obtain a composite powder; performing segmented hot-pressing sintering on the composite powder to obtain a composite material block; hot-extruding the composite material block into a filament to obtain a composite material filament; and performing plasma atomization on the composite material filament to obtain the Ti / Mg composite material powder. The preparation method has the advantages of simplicity, stability, easy operation, and the like, and the prepared Ti / Mg composite material powder has high sphericity, high fluidity, uniform composition, good dispersity, and the like, and can meet the requirements of the 3D printing process.

Description

Technical Field

[0001] This invention relates to the field of metal materials technology, and in particular to a method for preparing Ti / Mg composite powder for 3D printing. Background Technology

[0002] 3D printing (additive manufacturing), with its unique technological advantages, has been widely applied in aerospace, biomedicine, rail transportation, and other fields. Among them, Ti / Mg composite materials are a highly promising lightweight structural material for 3D printing, effectively reducing component weight while improving mechanical properties, meeting the dual demands of high-end equipment for lightweighting and high performance. The 3D printing process places stringent requirements on powder preparation, especially sphericity, flowability, compositional uniformity, and dispersibility, which directly determine the molding quality, density, and mechanical properties of 3D printed components. Currently, the main methods for preparing Ti / Mg composite powders include mechanical mixing and atomization, but these methods all have significant shortcomings and are difficult to meet the high standards required for 3D printing.

[0003] Mechanical mixing involves directly mixing Ti powder with Mg and magnesium alloy powders. While simple, this method suffers from uneven dispersion of the Ti and Mg-based powders, resulting in irregularly shaped powders with poor sphericity and flowability. Atomization, which directly mixes Ti powder with Mg and magnesium alloy powders and then atomizes the mixture, is prone to component segregation due to the significant density difference between Ti and Mg. Furthermore, nano-Ti powder tends to agglomerate during atomization, making uniform dispersion difficult and affecting the flowability in 3D printing. Therefore, there is an urgent need to develop a Ti / Mg composite powder suitable for the requirements of 3D printing processes. Summary of the Invention

[0004] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a method for preparing Ti / Mg composite powder.

[0005] The second objective of this invention is to provide the application of the above-mentioned method for preparing Ti / Mg composite powder in the preparation of 3D printing composite powder.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for preparing Ti / Mg composite powder, comprising the following steps: Titanium powder and magnesium source are mixed, and then ultrasonically dispersed and ground in sequence to obtain composite powder; The composite powder is subjected to segmented hot pressing and sintering to obtain a composite material block; The composite material block is hot-extruded into filaments to obtain composite material filaments; The composite material filaments are subjected to plasma atomization to obtain the Ti / Mg composite material powder; The atomization power of the plasma atomization is 30-60kW.

[0007] In some embodiments of the present invention, the titanium powder needs to be vacuum dried before use. The purpose of vacuum drying is to remove adsorbed moisture and impurities from the surface of the titanium powder.

[0008] In some embodiments of the present invention, the average particle size of the titanium powder is 2-15 μm. Choosing nano-titanium powder can fully utilize its reinforcing effect, and the nanoscale facilitates uniform dispersion on the magnesium source surface.

[0009] In some embodiments of the present invention, the purity of the titanium powder is ≥99.9%.

[0010] In some embodiments of the present invention, the magnesium source needs to be vacuum dried before use. The purpose of vacuum drying is to remove adsorbed moisture and impurities from the surface of the magnesium source.

[0011] In some embodiments of the present invention, the average particle size of the magnesium source is 10-200 μm; in some embodiments of the present invention, the average particle size of the magnesium source is 10-100 μm; in some embodiments of the present invention, the average particle size of the magnesium source is 50-100 μm. The particle size of the magnesium source is selected to suit the subsequent mixing and atomization processes, ensuring component uniformity.

[0012] In some embodiments of the present invention, the purity of the magnesium source is ≥99.5%.

[0013] In some embodiments of the present invention, the temperature of the vacuum drying process for the magnesium source and the titanium powder is 80-120°C.

[0014] In some embodiments of the present invention, the magnesium source and the titanium powder are vacuum dried for 2-4 hours.

[0015] In some embodiments of the present invention, the vacuum degree of the magnesium source and the titanium powder during vacuum drying is ≤10. -3 Pa.

[0016] The purpose of vacuum drying of titanium powder and magnesium source is to remove moisture and adsorbed oxygen from the surface of the powder (i.e., titanium powder and / or magnesium source), avoid defects such as pores and oxidation products during subsequent mixing, dispersion and sintering, and improve the dispersibility of the powder, laying the foundation for uniform mixing in the future.

[0017] In some embodiments of the present invention, mixing the titanium powder and the magnesium source is performed by mixing the titanium powder and the magnesium source under the protection of a protective gas; in some embodiments of the present invention, mixing the titanium powder and the magnesium source is performed by mixing the titanium powder and the magnesium source using a lightweight mixer under the protection of a protective gas.

[0018] In some embodiments of the present invention, the mixing speed in the step of mixing titanium powder and magnesium source is 60-200 r / min.

[0019] In some embodiments of the present invention, the mixing time for the step of mixing titanium powder and magnesium source is 5-20 hours.

[0020] In some embodiments of the present invention, in the step of mixing titanium powder and magnesium source, the protective gas includes at least one of nitrogen, argon, and helium.

[0021] In some embodiments of the present invention, the protective atmosphere in the step of mixing titanium powder and magnesium source is argon. In some embodiments of the present invention, the purity of argon is ≥99.99%. The use of high-purity argon in the present invention can prevent the powder from oxidizing during the mixing process and ensure the purity of the powder.

[0022] In some embodiments of the present invention, the particle size of the composite powder is 10-80 μm.

[0023] This invention first performs a preliminary mixing of magnesium source and titanium powder, which can achieve macroscopic uniform mixing of the two powders and avoid uneven dispersion caused by excessively high local concentrations during subsequent ultrasonic dispersion and grinding processes.

[0024] In some embodiments of the present invention, the segmented hot pressing sintering is performed in a hot pressing sintering mold.

[0025] In some embodiments of the present invention, the segmented hot pressing sintering is performed by sequentially performing a first stage hot pressing sintering, a second stage hot pressing sintering, and a third stage hot pressing sintering on the composite powder; the temperature of the second stage hot pressing sintering is 50-150°C higher than the temperature of the first stage hot pressing sintering; and the temperature of the third stage hot pressing sintering is 50-270°C higher than the temperature of the second stage hot pressing sintering.

[0026] In some embodiments of the present invention, the heating rate of the first stage hot pressing sintering is 5~15℃ / min; in some embodiments of the present invention, the heating rate of the first stage hot pressing sintering is any value of 5℃ / min, 8℃ / min, 10℃ / min, 12℃ / min, 14℃ / min, 15℃ / min or a range formed by any two of them.

[0027] In some embodiments of the present invention, the temperature of the first stage hot pressing sintering is 100~150℃; in some embodiments of the present invention, the temperature of the first stage hot pressing sintering is any value of 100℃, 110℃, 120℃, 130℃, 140℃, 150℃ or a range formed by any two of them.

[0028] In some embodiments of the present invention, the hot pressing pressure of the first stage hot pressing sintering is 10~30MPa; in some embodiments of the present invention, the hot pressing pressure of the first stage hot pressing sintering is any value of 10MPa, 13MPa, 15MPa, 18MPa, 20MPa, 22MPa, 25MPa, 28MPa, 30MPa or a range formed by any two of them.

[0029] In some embodiments of the present invention, the heat preservation and pressure holding time of the first stage hot pressing sintering is 5~10 min.

[0030] In some embodiments of the present invention, the vacuum degree of the first stage hot pressing sintering is 1×10⁻⁶. -2 ~5×10 - 2 Pa; In some embodiments of the present invention, the vacuum degree of the first stage hot pressing sintering is 1×10⁻⁶. -2 Pa, 2×10 -2 Pa, 3×10 -2 Pa, 4×10 -2 Pa, 5×10 -2 Any value in Pa, or a range of values ​​formed by any two of them.

[0031] In some embodiments of the present invention, the heating rate of the second stage hot pressing sintering is 3-8℃ / min; in some embodiments of the present invention, the heating rate of the second stage hot pressing sintering is any value of 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min or a range formed by any two of these values.

[0032] In some embodiments of the present invention, the temperature of the second stage hot pressing sintering is 200~300℃; in some embodiments of the present invention, the temperature of the second stage hot pressing sintering is any value of 200℃, 220℃, 240℃, 260℃, 280℃, 300℃ or a range formed by any two of them.

[0033] In some embodiments of the present invention, the hot pressing pressure of the second stage hot pressing sintering is 15~40MPa; in some embodiments of the present invention, the hot pressing pressure of the second stage hot pressing sintering is any value of 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa or a range formed by any two of them.

[0034] In some embodiments of the present invention, the heat preservation and pressure holding time for the second stage hot pressing sintering is 5 to 10 minutes.

[0035] In some embodiments of the present invention, the vacuum degree of the second stage hot pressing sintering is 0.8 × 10⁻⁶. -2 ~5×10 - 2 Pa; In some embodiments of the present invention, the vacuum degree of the second stage hot pressing sintering is 0.8 × 10⁻⁶. -2 Pa, 1×10 -2 Pa, 2×10 -2 Pa, 3×10 -2 Pa, 4×10 -2 Pa, 5×10 -2 Any value in Pa, or a range of values ​​formed by any two of them.

[0036] In some embodiments of the present invention, the heating rate of the third stage hot pressing sintering is 2-5℃ / min.

[0037] In some embodiments of the present invention, the temperature of the third stage hot pressing sintering is 350~470℃; in some embodiments of the present invention, the temperature of the third stage hot pressing sintering is any value of 350℃, 380℃, 400℃, 420℃, 440℃, 460℃, 470℃ or a range formed by any two of them.

[0038] In some embodiments of the present invention, the hot pressing pressure of the third stage hot pressing sintering is 25~45MPa; in some embodiments of the present invention, the hot pressing pressure of the third stage hot pressing sintering is any value of 25MPa, 30MPa, 35MPa, 40MPa, 45MPa or a range formed by any two of them.

[0039] In some embodiments of the present invention, the heat preservation and pressure holding time of the third stage hot pressing sintering is 10~30 min.

[0040] In some embodiments of the present invention, the vacuum degree of the third stage hot pressing sintering is 3 × 10⁻⁶. -3 ~8×10 - 3 Pa; In some embodiments of the present invention, the vacuum degree of the third stage hot pressing sintering is 3 × 10⁻⁶.-3 Pa, 4×10 -3 Pa, 5×10 -3 Pa, 6×10 -3 Pa, 7×10 -3 Pa, 8×10 -3 Any value in Pa, or a range of values ​​formed by any two of them.

[0041] In some embodiments of the present invention, the density of the composite material block is ≥98%.

[0042] The hot-pressing sintering in this invention utilizes the synergistic effect of high temperature and high pressure to induce plastic deformation, atomic diffusion, and interfacial reactions in the refined composite powder, achieving complete powder densification. Simultaneously, it strengthens the interfacial bonding between titanium powder and magnesium source powder, forming a stable interfacial transition layer (such as Ti-Al or Ti-Mg intermetallic compounds), preventing component segregation during subsequent atomization. The segmented hot-pressing temperature and pressure design involves venting at low temperatures for rapid heating, and slow heating at high temperatures to prevent magnesium source melting and loss, while pressurization ensures densification. Controlling the hot-pressing pressure and holding time ensures the density and interfacial bonding strength of the composite material block, laying the foundation for subsequent hot extrusion into fine filaments.

[0043] In some embodiments of the present invention, the particle size of the Ti / Mg composite material powder is 15-53 μm.

[0044] In some embodiments of the present invention, the magnesium source includes at least one of magnesium powder, AZ91D magnesium alloy powder, ZK60 magnesium alloy powder, ZK61 magnesium alloy powder, AZ61 magnesium alloy powder, AZ80 magnesium alloy powder, AM60 magnesium alloy powder, ZE33 magnesium alloy powder, ZE41 magnesium alloy powder, AZ31 magnesium alloy powder, and AZ31D magnesium alloy powder.

[0045] In some embodiments of the present invention, the average particle size of the magnesium source is 100-200 μm.

[0046] In some embodiments of the present invention, the mass of the titanium powder is 5-30% of the total mass of the titanium powder and the magnesium source; in other embodiments, the mass of the titanium powder is any value or a range formed by any combination of 5%, 10%, 15%, 20%, 25%, and 30% of the total mass of the titanium powder and the magnesium source. The present invention controls the mass ratio of titanium powder to magnesium source powder, allowing for flexible adjustment of the mechanical properties of the composite material to meet the needs of different 3D printed components.

[0047] In some embodiments of the present invention, the ultrasonic dispersion temperature is 0-10°C; in some embodiments of the present invention, the ultrasonic dispersion temperature is any value of 0°C, 1°C, 2°C, 4°C, 5°C, 6°C, 8°C, 10°C, or a range formed by any two of these values.

[0048] In some embodiments of the present invention, the power of the ultrasonic dispersion is 200-400W; in some embodiments of the present invention, the power of the ultrasonic dispersion is any value or a range formed by any two of 200W, 220W, 240W, 260W, 280W, 300W, 320W, 340W, 360W, 380W, and 400W.

[0049] In some embodiments of the present invention, the frequency of the ultrasonic dispersion is 20-40 kHz; in some embodiments of the present invention, the frequency of the ultrasonic dispersion is any value of 20 kHz, 22 kHz, 25 kHz, 28 kHz, 30 kHz, 32 kHz, 35 kHz, 38 kHz, 40 kHz or a range formed by any two of them.

[0050] In some embodiments of the present invention, the ultrasonic dispersion time is 20-60 min.

[0051] In some embodiments of the present invention, ethanol or acetone is used as the dispersion medium during ultrasonic dispersion.

[0052] In some embodiments of the present invention, the ultrasonic dispersion step is as follows: mixing the mixed powder of titanium powder and magnesium source with a dispersion medium, and ultrasonically dispersing it for 20-60 minutes at a temperature of 0-10°C, an ultrasonic power of 200-400W, and a frequency of 20-40kHz, and then vacuum drying to remove the dispersion medium.

[0053] In some embodiments of the present invention, the mass ratio of the dispersion medium to the mixed powder is (1~2):1. In some embodiments of the present invention, the ultrasonic dispersion is performed using an ice-water bath with temperature controlled at 0-10°C. The ice-water bath temperature control during ultrasonication breaks up agglomerates of titanium powder, achieving initial uniform dispersion of the two powders. Ice-water bath temperature control avoids excessive evaporation of the dispersion medium due to temperature increases during ultrasonication, while also preventing powder oxidation and grain growth, ensuring the stability of the dispersion effect.

[0054] Titanium powder is prone to agglomeration due to its large specific surface area and high surface energy. Direct ball milling is difficult to completely break up the titanium powder agglomerates. Ultrasonic dispersion can effectively break up the titanium powder agglomerates by utilizing the vibration of ultrasound, so that the titanium powder is evenly dispersed in the magnesium source powder. The addition of a dispersion medium can reduce the interaction force between powder particles and further improve the dispersion effect.

[0055] In some embodiments of the present invention, the composite material block is mechanically processed to remove the surface oxide scale before use, and then hot-extruded.

[0056] In some embodiments of the present invention, the diameter of the composite material filament is 1.5-8 mm; in some embodiments of the present invention, the diameter of the composite material filament is any value of 1.5 mm, 2 mm, 4 mm, 6 mm, 8 mm or a range formed by any two of them.

[0057] In some embodiments of the present invention, the density of the composite material filaments is ≥99%.

[0058] In some embodiments of the present invention, the hot extrusion is performed by preheating the composite material block to 320-420°C, and then hot extruding it using a die preheated to 280-400°C. Preheating the die to a temperature lower than the composite material block preheating temperature can improve the surface smoothness of the extruded composite material filaments.

[0059] In some embodiments of the present invention, the composite material block is preheated at 320~420℃ for 1-2.5h.

[0060] In some embodiments of the present invention, the mold is preheated at 280-400°C for 30-60 minutes.

[0061] In some embodiments of the present invention, the hot extrusion is performed using an extruder.

[0062] In some embodiments of the present invention, the extrusion rate of the hot extrusion is 0.1-0.5 mm / s.

[0063] In some embodiments of the present invention, the extrusion ratio during hot extrusion is (5~25):1.

[0064] In some embodiments of the present invention, the mold is a multi-hole mold; in some embodiments of the present invention, the mold is a multi-hole conical round hole mold.

[0065] In some embodiments of the present invention, the mold has 10-25 holes.

[0066] In some embodiments of the present invention, the diameter of the mold hole is 1-10 mm.

[0067] Multi-hole die extrusion can improve extrusion efficiency and reduce the extrusion ratio.

[0068] In some embodiments of the present invention, the preheating is performed in a heating furnace.

[0069] In some embodiments of the present invention, the die orifice is soaked in a graphite suspension for 10-30 minutes. Soaking in the graphite suspension provides lubrication during the extrusion process.

[0070] Hot extrusion can further improve the density of the composite material, refine the grains, and ensure the uniform distribution of the Ti phase in the Mg matrix. It also eliminates micropores generated during hot pressing and sintering, guaranteeing the uniformity of the composition and structure of the composite filaments. The preparation of the composite filaments allows for more uniform melt composition during subsequent plasma atomization, avoiding poor atomized powder quality caused by powder agglomeration or component segregation. This invention, by controlling the hot extrusion parameters, ensures the quality of the composite filament forming, avoiding defects such as cracking and deformation.

[0071] In some embodiments of the present invention, the plasma atomization uses an inert gas as the atomizing medium.

[0072] In some embodiments of the present invention, the flow rate of the inert gas is 30-60 L / min; in some embodiments of the present invention, the flow rate of the inert gas is any value of 30 L / min, 35 L / min, 40 L / min, 45 L / min, 50 L / min, 55 L / min, 60 L / min or a range formed by any two of these values.

[0073] In some embodiments of the present invention, the inert gas includes at least one of argon and helium. In some embodiments of the present invention, the plasma atomization uses argon as the atomizing medium.

[0074] In some embodiments of the present invention, the power of the plasma atomization is any value of 30kW, 35kW, 40kW, 45kW, 50kW, 55kW, 60kW, or a range formed by any two of them.

[0075] In some embodiments of the present invention, the atomization pressure of the plasma atomization is 0.3-0.8 MPa; in some embodiments of the present invention, the atomization pressure of the plasma atomization is any value of 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa or a range formed by any two of these values.

[0076] In some embodiments of the present invention, the feeding rate of the composite material filaments during plasma atomization is 0.5-2 mm / s.

[0077] In some embodiments of the present invention, the cooling rate during plasma atomization is 10. 4 ~10 5 ℃ / s.

[0078] In this invention, during plasma atomization, the high temperature of the plasma arc melts the composite material filaments, forming tiny droplets. These droplets are then rapidly cooled by a high-speed atomizing medium (i.e., argon gas flow) at a cooling rate of 10. 4 ~10 5 (℃ / s), and after solidification, spherical powder of Ti / Mg composite material was collected.

[0079] In some embodiments of the present invention, the preparation method further includes a step of sieving using a standard sieve of 15-53 μm, which is performed after the plasma atomization step. Sieving with a standard sieve of 15-53 μm removes powder particles of unqualified sizes, resulting in spherical Ti / Mg composite powder that meets the requirements for 3D printing.

[0080] Plasma atomization offers advantages such as high atomization temperature, rapid cooling rate, high sphericity of atomized powder, and good flowability, effectively solving the problems of poor sphericity and insufficient flowability in existing atomization methods for preparing Ti / Mg composite powders. Using composite material filaments as atomization raw materials ensures uniform composition and structure, avoiding powder segregation caused by uneven raw material composition during atomization. High-speed cooling inhibits Ti phase agglomeration and grain growth, guaranteeing powder dispersibility and fineness. The sieving step controls the powder particle size distribution within the 15~53μm range suitable for 3D printing, ensuring powder flowability and molding performance, ultimately yielding powders with sphericity ≥90%, flowability ≤20s / 50g, and loose density ≥1.2g / cm³. 3 Ti / Mg composite powder for 3D printing.

[0081] In some embodiments of the present invention, the grinding is performed by mixing and grinding ultrasonically dispersed powder with grinding media and optionally added dispersant under the protection of a protective gas.

[0082] In some embodiments of the present invention, the mass ratio of the ultrasonically dispersed mixed powder to the grinding medium is (5~15):1.

[0083] In some embodiments of the present invention, the grinding media includes at least one of zirconia balls and alumina balls. Zirconia ball grinding media have high hardness and good wear resistance, which can avoid powder contamination caused by wear of the grinding media.

[0084] In some embodiments of the present invention, the particle size of the grinding media is 5-15 mm.

[0085] In some embodiments of the present invention, the dispersant includes at least one selected from stearic acid and zinc stearate. The addition of the dispersant prevents powder agglomeration during ball milling, further improving dispersion uniformity.

[0086] In some embodiments of the present invention, the mass of the dispersant is 0.1-0.5% of the mass of the ultrasonically dispersed mixed powder.

[0087] In some embodiments of the present invention, the protective gas includes at least one of nitrogen, argon, and helium.

[0088] In some embodiments of the present invention, the grinding is performed using a planetary ball mill. The high-speed rotation of the planetary ball mill generates strong impact, grinding, and shearing effects, which on the one hand further refines the magnesium source powder, and on the other hand, allows the titanium powder to fully contact the magnesium source powder, promotes interfacial atomic diffusion, forms preliminary interfacial bonding, and avoids interfacial separation during subsequent sintering.

[0089] In some embodiments of the present invention, the grinding speed during grinding is 200-400 r / min.

[0090] In some embodiments of the present invention, the grinding time is 2-8 hours. The purpose of grinding is to refine the powder, achieve uniform mixing and preliminary interfacial bonding, and obtain refined composite powder with a particle size of 10-80 μm.

[0091] This invention strictly controls the grinding parameters, which can avoid stress defects caused by excessive powder refinement and ensure the subsequent forming performance of the powder.

[0092] The application of the method for preparing Ti / Mg composite powder in the preparation of 3D printing composite powder.

[0093] The beneficial effects of this invention are: the preparation method of this invention has the advantages of simple preparation method, stable process, easy operation, and mass production capability, and the obtained Ti / Mg composite material powder has high sphericity, high fluidity, uniform composition, and good dispersibility, which can adapt to the requirements of 3D printing process. The specific analysis is as follows: This invention employs a process of initial mixing, followed by ultrasonic dispersion and grinding to obtain powder, which is then hot-pressed and sintered, hot-extruded into filaments, and finally plasma-atomized. This method overcomes the limitations of existing Ti / Mg composite powder preparation methods by innovatively using a process of "first densifying and shaping into fine filaments, then plasma-atomizing." This effectively solves the core technical problems of uneven dispersion, component segregation, poor sphericity, and insufficient flowability in existing composite powders. Compared with existing methods such as mechanical mixing, direct atomization, and simple ball milling, the prepared powder is more suitable for 3D printing process requirements.

[0094] This invention achieves uniform dispersion of the Ti phase in a Mg-based matrix through multi-step dispersion (e.g., ultrasonic dispersion, grinding) and densification treatment (e.g., hot pressing sintering, hot extrusion), avoiding Ti powder agglomeration. Then, a composite powder is prepared by plasma atomization, resulting in a powder with high sphericity (≥90%), good flowability (≤20s / 50g), uniform particle size distribution (15~53μm), and high density. This fully meets the stringent requirements of 3D printing processes such as selective laser melting and electron beam melting for powders. 3D printed components prepared using this powder have a density ≥98%, tensile strength ≥320MPa, and elongation ≥8%, with mechanical properties significantly superior to components prepared by existing methods.

[0095] The preparation method in this invention is scientifically sound and highly controllable: each process step is closely linked, and the process parameters of each step (such as temperature, pressure, rotation speed, and time) can be precisely controlled. By adjusting the ratio of titanium powder to magnesium source powder, ball milling parameters, hot pressing parameters, atomization parameters, etc., the composition, particle size, sphericity, and mechanical properties of the composite powder can be flexibly controlled to meet the preparation needs of 3D printed components in different fields. The entire process route does not generate any toxic or harmful gases, is green and environmentally friendly, and avoids excessive oxidation of the powder, ensuring the purity and performance stability of the powder.

[0096] The preparation method of this invention has low production cost and is suitable for large-scale production: the lightweight mixer, ultrasonic dispersion equipment, planetary ball mill, hot pressing sintering furnace, hot extruder, and plasma atomization equipment used in this invention are all commonly used industrial equipment, requiring no special equipment and resulting in low equipment investment costs; the process steps are simple, the operation is convenient, and the production efficiency is high, enabling automated and large-scale production. Compared with existing methods for preparing Ti / Mg composite powder for 3D printing, the production cost is reduced by more than 30%, demonstrating significant industrial application value.

[0097] The Ti / Mg composite powder prepared by this invention can be widely used in the fabrication of 3D printed components in aerospace, biomedicine, rail transportation, and electronic products. It can be used to prepare both lightweight structural components and high-performance functional components, solving the problem that existing Ti / Mg composite powders are difficult to adapt to 3D printing processes and promoting the industrial application of Ti / Mg composite materials. Attached Figure Description

[0098] Figure 1 This is a photograph of the Ti / AZ91D composite filaments from Example 1.

[0099] Figure 2 The image shows scanning electron microscope (SEM) images of the surface and cross-section of the Ti / Mg composite powder in Example 1.

[0100] Figure 3The image shows a cross-sectional SEM image of the Ti / AZ91D composite powder in Comparative Example 1.

[0101] Figure 4 The image shows a cross-sectional SEM image of the Ti / AZ31 composite powder in Comparative Example 3.

[0102] Figure 5 The image shows a cross-sectional scanning electron microscope (SEM) image of a component printed from the Ti / Mg composite powder of Example 1 using selective laser melting (SLM) 3D printing.

[0103] Figure 6 The figures show the room temperature tensile properties of the Ti / Mg composite components in Examples 1-2 and Comparative Example 1. Detailed Implementation

[0104] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0105] Terminology definition: The ball-to-material ratio is the mass ratio of zirconia balls to mixed powder; The extrusion ratio is the ratio of the cross-sectional area of ​​the extrusion cylinder cavity to the total cross-sectional area of ​​the extruded product; it is also called the extrusion coefficient.

[0106] Example 1 This embodiment provides a method for preparing Ti / Mg composite powder for 3D printing. The specific preparation steps are as follows: 1) Raw material pretreatment: Submicron Ti powder with an average particle size of 10 μm and a purity of 99.9% and AZ91D magnesium alloy powder with an average particle size of 70 μm and a purity of 99.5% were selected and subjected to pretreatment at 100℃ and a vacuum degree of 10. -3 Dry under Pa conditions for 3 hours to remove surface moisture and impurities from the powder; 2) Preliminary mixing in a light mixer: 99 wt% AZ91D magnesium alloy powder and 1 wt% submicron Ti powder were added to a light mixer, protected by high-purity argon gas (99.99% purity), and mixed for 8 hours at a speed of 100 r / min to obtain a mixed powder precursor. 3) Ultrasonic dispersion: The mixed powder precursor was placed in an ultrasonic dispersion device, and anhydrous ethanol was added as the dispersion medium (the mass ratio of dispersion medium to mixed powder precursor was 1.5:1). The mixture was ultrasonically dispersed for 40 minutes at a power of 300W and a frequency of 30kHz. During the ultrasonic process, the temperature was controlled by an ice-water bath (temperature was 5℃). After ultrasonication, the mixture was vacuum dried to remove the anhydrous ethanol. 4) Planetary ball mill treatment: The dried mixed powder is transferred to a planetary ball mill, zirconia balls (ball-to-powder ratio of 10:1, average particle size of zirconia balls of 10 mm) are added, and stearic acid of 0.3% by mass (based on the mass fraction of the mixed powder of 100%) is added as a dispersant. High-purity argon gas is introduced for protection, and the mixture is ball-milled at 300 r / min for 5 h to obtain a fine composite powder with a particle size of 30~60 μm. 5) Hot pressing sintering: The refined composite powder is placed in a hot pressing sintering mold, and the vacuum degree throughout the process is 3×10⁻⁶. -3 The temperature was increased to 150℃ at a heating rate of 10℃ / min, and a hot-pressing pressure of 25MPa was applied. The temperature was held for 5 minutes. Then, the temperature was increased to 300℃ at a heating rate of 8℃ / min, and a hot-pressing pressure of 30MPa was applied. The temperature was held for 8 minutes. Finally, the temperature was increased to 420℃ at a heating rate of 5℃ / min, and a hot-pressing pressure of 40MPa was applied. The temperature was held for 15 minutes. The mixture was then cooled to room temperature to obtain a densified Ti / Mg composite material block with a density of 98.5%. 6) Hot extrusion into filaments: The surface oxide scale of the composite material block was removed. The extrusion die was preheated at 380℃ for 45 min, and the composite material block was preheated at 420℃ for 120 min. Then, hot extrusion was carried out in a porous extrusion die (the die orifice needed to be soaked in graphite suspension for 15 min) at an extrusion rate of 0.3 mm / s and an extrusion ratio of 10:1 to obtain Ti / AZ91D composite material filaments with a diameter of 2 mm and a density of 99.8%. The actual object is shown in the figure. Figure 1 As shown, by Figure 1 It can be seen that the Ti / AZ91D composite filaments prepared in this example have uniform filament diameter and smooth surface, which provides a basis for subsequent plasma atomization. 7) Plasma atomization and sieving: The composite material filaments are fed into a plasma atomization device, using high-purity argon as the atomization medium. The flow rate of high-purity argon is 45 L / min. The plasma power is adjusted to 45 kW, the atomization pressure to 0.5 MPa, and the filament feeding rate to 1 mm / s. After atomization, the filaments are sieved at a rate of 10... 5 The product was cooled at a cooling rate of ℃ / s and collected. It was then sieved using a standard sieve of 15~53μm to obtain the Ti / Mg composite powder used for 3D printing in this example.

[0107] Example 2 This embodiment provides a method for preparing Ti / Mg composite powder for 3D printing. The specific preparation steps are as follows: 1) Raw material pretreatment: Submicron Ti powder with an average particle size of 10 μm and a purity of 99.9% and AZ31 magnesium alloy powder with an average particle size of 70 μm and a purity of 99.5% were selected and subjected to pretreatment at 100℃ and a vacuum degree of 10. -3 Dry under Pa conditions for 3 hours to remove surface moisture and impurities; 2) Preliminary mixing in a light mixer: 15 wt% submicron Ti powder and 85 wt% AZ31 magnesium alloy powder are added to a light mixer, protected by high-purity argon gas (99.99% purity), and mixed for 15 h at a speed of 100 r / min to obtain a mixed powder precursor. 3) Ultrasonic dispersion: The mixed powder precursor was placed in an ultrasonic dispersion device, and anhydrous ethanol was added as the dispersion medium (the mass ratio of dispersion medium to mixed powder precursor was 1.5:1). The mixture was ultrasonically dispersed for 40 minutes at a power of 300W and a frequency of 30kHz. During the ultrasonic process, the temperature was controlled by an ice-water bath (temperature was 5℃). After ultrasonication, the anhydrous ethanol was removed by vacuum drying. 4) Planetary ball mill treatment: The dried mixed powder is transferred to a planetary ball mill, zirconia balls (ball-to-powder ratio 15:1, average particle size of zirconia balls 10 mm) are added, and 0.3% stearic acid (calculated based on the mass fraction of the mixed powder as 100%) is added as a dispersant. High-purity argon gas is introduced for protection, and the mixture is ball-milled at 300 r / min for 6 h to obtain a refined composite powder with a particle size of 30~60 μm. 5) Hot pressing sintering: The refined composite powder is placed in a hot pressing sintering mold, and the vacuum degree throughout the process is 3×10⁻⁶. -3 The temperature was increased to 150℃ at a heating rate of 10℃ / min, and a hot-pressing pressure of 25MPa was applied. The temperature was held for 5 minutes. Then, the temperature was increased to 310℃ at a heating rate of 8℃ / min, and a hot-pressing pressure of 30MPa was applied. The temperature was held for 8 minutes. Finally, the temperature was increased to 400℃ at a heating rate of 5℃ / min, and a hot-pressing pressure of 40MPa was applied. The temperature was held for 18 minutes. The mixture was then cooled to room temperature to obtain a densified Ti / Mg composite material block with a density of 98.5%. 6) Hot extrusion into filaments: Remove the surface oxide scale from the composite material block, preheat the extrusion die at 380℃ for 45 min, preheat the composite material block at 420℃ for 120 min, and hot extrude at an extrusion rate of 0.3 mm / s and an extrusion ratio of 10:1 to obtain Ti / AZ31 composite material filaments with a diameter of 2 mm and a density of 99.8%. 7) Plasma atomization and sieving: The composite material filaments are fed into a plasma atomization device, using high-purity argon as the atomization medium. The flow rate of high-purity argon is 45 L / min. The plasma power is adjusted to 50 kW, the atomization pressure to 0.5 MPa, and the filament feeding rate to 1 mm / s. After atomization, the filaments are sieved at a rate of 10... 5 The product was cooled at a cooling rate of ℃ / s and collected. It was then sieved using a standard sieve of 15~53μm to obtain the Ti / Mg composite powder used for 3D printing in this example.

[0108] Comparative Example 1 This embodiment provides a method for preparing Ti / Mg composite powder for 3D printing. The specific preparation steps are as follows: 1) Raw material pretreatment: Submicron Ti powder with an average particle size of 10 μm and a purity of 99.9% and AZ91D magnesium alloy powder with an average particle size of 70 μm and a purity of 99.5% were selected and subjected to pretreatment at 100℃ and a vacuum degree of 10. -3 Dry under Pa conditions for 3 hours to remove surface moisture and impurities; 2) Preliminary mixing in a light mixer: 99 wt% AZ91D magnesium alloy powder and 1 wt% submicron Ti powder were added to a light mixer, protected by high-purity argon gas (99.99% purity), and mixed for 8 hours at a speed of 100 r / min to obtain a mixed powder precursor. 3) Ultrasonic dispersion: The mixed powder precursor was placed in an ultrasonic dispersion device, and anhydrous ethanol was added as the dispersion medium (the mass ratio of dispersion medium to mixed powder precursor was 1.5:1). The mixture was ultrasonically dispersed for 40 minutes at a power of 300W and a frequency of 30kHz. During the ultrasonic process, the temperature was controlled by an ice-water bath (5℃). After ultrasonication, the anhydrous ethanol was removed by vacuum drying. 4) Planetary ball mill treatment: The dried mixed powder is transferred to a planetary ball mill, zirconia balls (ball-to-powder ratio 10:1, average particle size of zirconia balls 10 mm) are added, and 0.3% stearic acid (based on the mass fraction of the mixed powder as 100%) is added as a dispersant. High-purity argon gas is introduced for protection, and the mixture is ball-milled at 300 r / min for 5 h to obtain a fine composite powder with a particle size of 30~60 μm. 5) Stirring casting: The refined composite powder is placed in a vacuum stirring furnace and heated to 730°C to form a composite material melt. The mixture is stirred in one direction at a speed of 900 r / min for 10 min. The furnace is kept under a slight positive pressure throughout the stirring process. The holding time is 15 min. The composite material melt is then cast into a Ti / Mg composite material block. 6) Hot extrusion into filaments: Remove the surface oxide scale from the composite material block, preheat the extrusion die at 380℃ for 45 min, preheat the composite material at 420℃ for 120 min, and hot extrude it at an extrusion rate of 0.3 mm / s and an extrusion ratio of 10:1 in a porous extrusion die (the die holes need to be soaked in graphite suspension for 15 min) to obtain Ti / AZ91D composite material filaments with a diameter of 2 mm and a density of 99.2%. 7) Plasma atomization and sieving: The composite material filaments are fed into a plasma atomization device, using high-purity argon as the atomization medium. The flow rate of high-purity argon is 45 L / min. The plasma power is adjusted to 45 kW, the atomization pressure to 0.5 MPa, and the filament feeding rate to 1 mm / s. After atomization, the filaments are sieved at a rate of 10... 5 The product was cooled at a cooling rate of ℃ / s and collected. It was then sieved using a standard sieve of 15~53μm to obtain the Ti / Mg composite powder used for 3D printing in this example.

[0109] Comparative Example 2 This embodiment provides a method for preparing Ti / Mg composite powder for 3D printing. The specific preparation steps are as follows: 1) Raw material pretreatment: Submicron Ti powder with an average particle size of 10 μm and a purity of 99.9% was selected, and AZ31 magnesium alloy powder with an average particle size of 70 μm and a purity of 99.5% was selected. The powders were then subjected to pretreatment at 100℃ and a vacuum degree of 10... -3 Dry under Pa conditions for 3 hours to remove surface moisture and impurities; 2) Preliminary mixing in a light mixer: 15 wt% submicron Ti powder and 85 wt% AZ31 magnesium alloy powder are added to a light mixer, protected by high-purity argon gas (99.99% purity), and mixed for 15 h at a speed of 100 r / min to obtain a mixed powder precursor. 3) Ultrasonic dispersion: The mixed powder precursor was placed in an ultrasonic dispersion device, and anhydrous ethanol was added as the dispersion medium (the mass ratio of dispersion medium to mixed powder precursor was 1.5:1). The mixture was ultrasonically dispersed for 40 minutes at a power of 300W and a frequency of 30kHz. During the ultrasonic process, the temperature was controlled by an ice-water bath (5℃). After ultrasonication, the anhydrous ethanol was removed by vacuum drying. 4) Planetary ball mill treatment: The dried mixed powder is transferred to a planetary ball mill, zirconia balls (ball-to-powder ratio 15:1, average particle size of zirconia balls 10 mm) are added, and 0.3% stearic acid (calculated based on the mass fraction of the mixed powder as 100%) is added as a dispersant. High-purity argon gas is introduced for protection, and the mixture is ball-milled at 300 r / min for 6 h to obtain a refined composite powder with a particle size of 30~60 μm. 5) Hot pressing sintering: The refined composite powder is placed in a hot pressing sintering mold, and the vacuum degree throughout the process is 3×10⁻⁶. -3 The temperature was increased to 400℃ at a heating rate of 10℃ / min, and a hot pressing pressure of 25MPa was applied. The temperature and pressure were held for 5 minutes, and then cooled to room temperature to obtain a Ti / Mg composite material block with a density of 92.5% and a large loss of mass, which could not be subjected to subsequent hot extrusion.

[0110] 6) Hot extrusion into fine filaments: This process cannot be carried out due to severe losses and segregation during sintering.

[0111] This example uses a one-stage hot pressing sintering temperature and pressure, which is difficult to control during the sintering process. Magnesium alloys are highly temperature sensitive, and if the sintering temperature is slightly too high, a large amount of magnesium alloy will overflow, causing compositional deviation and quality loss. At the same time, it will seriously contaminate the furnace and damage the mold. Therefore, this invention adopts segmented sintering to ensure the homogenization and densification of Ti / Mg composite materials to meet the requirements of 3D printing.

[0112] Comparative Example 3 This embodiment provides a method for preparing Ti / Mg composite powder for 3D printing. The specific preparation steps are as follows: 1) Raw material pretreatment: Submicron Ti powder with an average particle size of 10 μm and a purity of 99.9% was selected, and AZ31 magnesium alloy powder with an average particle size of 70 μm and a purity of 99.5% was selected. The powders were then subjected to pretreatment at 100℃ and a vacuum degree of 10... -3 Dry under Pa conditions for 3 hours to remove surface moisture and impurities; 2) Preliminary mixing in a light mixer: 15 wt% submicron Ti powder and 85 wt% AZ31 magnesium alloy powder are added to a light mixer, protected by high-purity argon gas (99.99% purity), and mixed for 15 h at a speed of 100 r / min to obtain a mixed powder precursor. 3) Ultrasonic dispersion: The mixed powder precursor was placed in an ultrasonic dispersion device, and anhydrous ethanol was added as the dispersion medium (the mass ratio of dispersion medium to mixed powder precursor was 1.5:1). The mixture was ultrasonically dispersed for 40 minutes at a power of 300W and a frequency of 30kHz. During the ultrasonic process, the temperature was controlled by an ice-water bath (5℃). After ultrasonication, the anhydrous ethanol was removed by vacuum drying. 4) Planetary ball mill treatment: The dried mixed powder is transferred to a planetary ball mill, zirconia balls (ball-to-powder ratio 15:1, average particle size of zirconia balls 10 mm) are added, and 0.3% stearic acid (calculated based on the mass fraction of the mixed powder as 100%) is added as a dispersant. High-purity argon gas is introduced for protection, and the mixture is ball-milled at 300 r / min for 6 h to obtain a refined composite powder with a particle size of 30~60 μm. 5) Hot pressing sintering: The refined composite powder is placed in a hot pressing sintering mold, and the vacuum degree throughout the process is 3×10⁻⁶. -3 The temperature was increased to 150℃ at a heating rate of 10℃ / min, and a hot-pressing pressure of 25MPa was applied. The temperature was held for 5 minutes. Then, the temperature was increased to 310℃ at a heating rate of 8℃ / min, and a hot-pressing pressure of 30MPa was applied. The temperature was held for 8 minutes. Finally, the temperature was increased to 400℃ at a heating rate of 5℃ / min, and a hot-pressing pressure of 40MPa was applied. The temperature was held for 18 minutes. The mixture was then cooled to room temperature to obtain a densified Ti / Mg composite material block with a density of 98.5%. 6) Hot extrusion into filaments: Remove the surface oxide scale from the composite material block, preheat the extrusion die at 380℃ for 45 min, preheat the composite material block at 420℃ for 120 min, and hot extrude at an extrusion rate of 0.3 mm / s and an extrusion ratio of 10:1 to obtain Ti / AZ31 composite material filaments with a diameter of 2 mm and a density of 99.2%. 7) Plasma atomization and sieving: The composite material filaments are fed into a plasma atomization device, using high-purity argon as the atomization medium. The flow rate of high-purity argon is 45 L / min. The plasma power is adjusted to 70 kW, the atomization pressure to 0.5 MPa, and the filament feeding rate to 1 mm / s. After atomization, the filaments are sieved at a rate of 10... 5 The product was cooled at a cooling rate of ℃ / s and collected to obtain a small amount of Ti / Mg composite powder.

[0113] The Ti / Mg composite powder in this comparative example has poor sphericity, an uneven powder surface, a particle size distribution of ≤15μm, and extremely uneven Ti particle distribution. The plasma equipment cavity is contaminated, and the obtained Ti / Mg composite powder cannot be used for selective laser melting 3D printing.

[0114] Performance testing: Scanning electron microscopy (SEM) images of the surface and cross-section of the Ti / Mg composite powder prepared in Example 1 were obtained, as shown in the figure below. Figure 2 As shown, where, Figure 2 Image (a) is a scanning electron microscope image of the surface. Figure 2 Image (b) in the diagram is a scanning electron microscope (SEM) image of the cross-section. (From...) Figure 2It can be seen that the silver-white spheres embedded on the surface of the AZ91D particles in Example 1 are Ti particles. The AZ91D particles and Ti particles are tightly bonded, and there is no obvious agglomeration between the Ti particles. Furthermore, the prepared Ti / Mg composite material has high sphericity, uniform particle size distribution, and no obvious agglomeration, further indicating that in the Ti / Mg composite powder of Example 1, the Ti phase is uniformly dispersed in the AZ91D magnesium matrix, without obvious agglomeration or component segregation. Testing in Example 2 showed that the Ti phase is uniformly dispersed in the AZ31 magnesium matrix, and no obvious agglomeration or component segregation was also observed. Scanning electron microscopy (SEM) was used to examine the cross-sectional SEM images of the composite powders prepared in Comparative Examples 1 and 3, as shown in the figures below. Figure 3 and Figure 4 As shown. By Figure 3 It can be seen that significant agglomeration behavior exists in the cross-section of the Ti / AZ91D composite powder. This is due to the large-scale agglomeration of powder caused by the uneven dispersion of Ti particles during the stirred casting process, which seriously affects the material properties. Figure 4 As can be seen, after the plasma atomization power of Comparative Example 3 was increased, the powder characteristics and state were completely lost, and it could no longer be used for subsequent 3D printing.

[0115] The sphericity, flowability, bulk density, and particle size distribution of the Ti / Mg composite powders prepared in Examples 1-2 were tested respectively. The specific tests were as follows: Sphericity: Tested according to the test method described in GB / T39251-2020 standard; Flowability: Tested according to the test methods described in GB / T 1482-2022 standard; Loose packing density: Tested according to the test method described in GB / T 1479.1-2011 standard; The properties of the Ti / Mg composite powders of Examples 1-2, measured according to the above test methods, are shown in Table 1 below.

[0116] Table 1 Properties of Ti / Mg composite powder

[0117] As shown in Table 1, the Ti / Mg composite powders prepared in Examples 1-2 of this invention have high sphericity (above 90%), good flowability (15-18 s / 50 g), and high bulk density (>1.0 g / cm³). 3 ).

[0118] The Ti / Mg composite powders from Examples 1-2 and Comparative Example 1 were printed into components using selective laser melting 3D printing. The printing parameters were: laser power 182W, scanning speed 360mm / s, scanning spacing 60μm, powder layer thickness 30μm, and substrate preheating 205℃.

[0119] In Example 1, the Ti / Mg composite powder was printed into Ti / Mg composite components using the selective laser melting 3D printing method described above. The cross-sectional scanning electron microscope (SEM) images of the components were then analyzed. Specifically, as shown below... Figure 5 As shown. Figure 5 The spheres in the image are Ti particles, and the AZ91D particles are encapsulated inside the Ti particles. The Ti particles and AZ91D particles are tightly bound together and there is no obvious aggregation.

[0120] Then, the density and mechanical properties of the component are tested. The specific testing methods are as follows: Density: Tested according to the test method described in GB / T 3850-2015 standard; Tensile strength at room temperature: Tested according to the test method described in GB / T 228.1-2021 standard; The room temperature tensile properties of the Ti / Mg composite components in Examples 1-2 and Comparative Example 1 are as follows: Figure 6 As shown in Table 2, the performance data obtained by the above testing method are shown below.

[0121] Table 2. Performance of components 3D printed from Ti / Mg composite powder

[0122] Depend on Figure 6 As shown in Table 2, compared with Comparative Example 1, the components of Ti / Mg composite powder in Examples 1-2 after selective laser melting 3D printing have higher density, higher room temperature tensile strength and higher elongation, specifically: density of 98.5-98.8%, tensile strength of 280-353 MPa and elongation of 8.2-9.5%.

[0123] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing Ti / Mg composite powder, characterized in that: Includes the following steps: Titanium powder and magnesium source are mixed, and then ultrasonically dispersed and ground in sequence to obtain composite powder; The composite powder is subjected to segmented hot pressing and sintering to obtain a composite material block; The composite material block is hot-extruded into filaments to obtain composite material filaments; The composite material filaments are subjected to plasma atomization to obtain the Ti / Mg composite material powder; The atomization power of the plasma atomization is 30-60kW.

2. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The segmented hot pressing sintering process involves sequentially performing a first-stage hot pressing sintering, a second-stage hot pressing sintering, and a third-stage hot pressing sintering on the composite powder. The temperature of the second-stage hot pressing sintering is 50-150°C higher than that of the first-stage hot pressing sintering, and the temperature of the third-stage hot pressing sintering is 50-270°C higher than that of the second-stage hot pressing sintering.

3. The method for preparing Ti / Mg composite powder according to claim 2, characterized in that: The first stage of hot pressing sintering has at least one of the following characteristics: (a1) The heating rate of the first stage hot pressing sintering is 5~15℃ / min; (a2) The temperature of the first stage hot pressing sintering is 100~150℃; (a3) The hot pressing pressure of the first stage hot pressing sintering is 10~30MPa; (a4) The heat preservation and pressure holding time for the first stage of hot pressing sintering is 5~10 min; (a5) The vacuum degree of the first stage hot pressing sintering is 1×10 -2 ~5×10 -2 Pa; And / or, The second stage of hot pressing sintering has at least one of the following characteristics: (b1) The heating rate of the second stage hot pressing sintering is 3-8℃ / min; (b2) The temperature of the second stage hot pressing sintering is 200~300℃; (b3) The hot pressing pressure of the second stage hot pressing sintering is 15~40MPa; (b4) The heat preservation and pressure holding time for the second stage hot pressing sintering is 5~10 min; (b5) The vacuum degree of the second stage hot pressing sintering is 0.8 × 10⁻⁶. -2 ~5×10 -2 Pa; And / or, The third stage of hot pressing sintering has at least one of the following characteristics: (c1) The heating rate of the third stage hot pressing sintering is 2-5℃ / min; (c2) The temperature of the third stage hot pressing sintering is 350~470℃; (c3) The hot pressing pressure of the third stage hot pressing sintering is 25~45MPa; (c4) The heat preservation and pressure holding time for the third stage hot pressing sintering is 10~30min; (c5) The vacuum degree of the third stage hot pressing sintering is 3×10⁻⁶. -3 ~8×10 -3 Pa.

4. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The density of the composite material block is ≥98%; And / or, the diameter of the composite material filaments is 1.5-8 mm; And / or, the particle size of the Ti / Mg composite powder is 15-53 μm.

5. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The titanium powder has an average particle size of 2-15 μm; And / or, the magnesium source includes at least one of magnesium powder, AZ91D magnesium alloy powder, ZK60 magnesium alloy powder, ZK61 magnesium alloy powder, AZ61 magnesium alloy powder, AZ80 magnesium alloy powder, AM60 magnesium alloy powder, ZE33 magnesium alloy powder, ZE41 magnesium alloy powder, AZ31 magnesium alloy powder, and AZ31D magnesium alloy powder. And / or, the average particle size of the magnesium source is 100-200 μm; And / or, the mass of the titanium powder is 5-30% of the total mass of the titanium powder and the magnesium source.

6. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The temperature for ultrasonic dispersion is 0-10℃; And / or, the power during ultrasonic dispersion is 200-400W; And / or, the frequency of the ultrasonic dispersion is 20-40 kHz.

7. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The hot extrusion process involves preheating the composite material block to 320-420°C and then performing hot extrusion using a mold preheated to 280-400°C.

8. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The plasma atomization has at least one of the following characteristics: (d1) The plasma atomization described herein uses an inert gas as the atomizing medium; (d2) The atomization pressure of the plasma atomization is 0.3-0.8 MPa; (d3) The feeding rate of the composite material filaments during plasma atomization is 0.5-2 mm / s.

9. The method for preparing Ti / Mg composite powder according to claim 1, characterized in that: The grinding process involves mixing and grinding the ultrasonically dispersed powder with grinding media and optionally added dispersant under the protection of a protective gas.

10. The application of the method for preparing Ti / Mg composite powder according to any one of claims 1-9 in the preparation of 3D printing composite powder.

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