Composite powder material for additive manufacturing and preparation method thereof

Abstract

The invention relates to the technical field of powder metallurgy, in particular to a composite powder material for additive manufacturing and a preparation method thereof.The preparation method comprises the following steps that nano metal powder and micron non-metal ceramic powder are added into a mixing tank, a protective atmosphere is formed in the mixing tank, the gas pressure in the tank and the tank temperature are set, and the temperature of the tank is set; a three-section acoustic resonance method is adopted for coating and powder preparation, nano metal powder is used for coating micron nonmetal ceramic powder, and the composite powder material with a core-shell structure is prepared. In the three-section acoustic resonance method, the resonance frequency of the first section is 20 Hz-50 Hz, the mixing acceleration is 10 g-100 g, and the mixing time is 1 min-5 min; in the second stage, the resonant frequency is 60 Hz-100 Hz, the mixing acceleration is 110 g-200 g, and the mixing time is 3 min-20 min; and in the third stage, the resonant frequency is 40-70 Hz, the mixing acceleration is 80-130 g, and the mixing time is 1-10 min.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, specifically to a composite powder material for additive manufacturing and its preparation method. Background Technology

[0002] Additive manufacturing technology, as an emerging manufacturing process, has shown broad application prospects in aerospace, automotive manufacturing, and other fields. However, traditional powder materials for additive manufacturing face many technical bottlenecks, especially in the preparation of metal-ceramic composite powders, which present significant challenges. Currently common mechanical mixing methods struggle to achieve uniform coating of micron-sized ceramic powders with nano-sized metal powders, leading to problems such as component segregation and poor interfacial bonding during additive manufacturing. Furthermore, conventional preparation methods often require the addition of binders or high-temperature treatment, which not only introduces impurities but may also alter the original morphology of the powder.

[0003] In additive manufacturing, the interfacial bonding quality of metal-ceramic composite powders directly affects the mechanical properties of the final part. In existing technologies, composite powders prepared by ball milling are prone to excessive cold welding or powder breakage; while wet chemical methods, although achieving better coating effects, suffer from drawbacks such as complex processes, high costs, and low yields. Of particular note is the difficulty in precisely controlling the coating thickness and uniformity of the nano-metal layer on the surface of micron-sized ceramic particles using current methods, which severely restricts the application of composite powders in additive manufacturing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite powder material for additive manufacturing and its preparation method, which solves the technical problem of poor interfacial bonding quality of metal-ceramic composite powders prepared by existing processes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing composite powder materials for additive manufacturing, comprising the following steps: Nanoscale metal powder and micron-sized non-metallic ceramic powder are added to a mixing tank, a protective atmosphere is formed inside the mixing tank, and the gas pressure and temperature inside the tank are set. A three-stage acoustic resonance method is used for coating powder preparation, in which nanoscale metal powder is coated with micron-sized non-metallic ceramic powder to obtain a composite powder material with a core-shell structure.

[0006] In the three-segment acoustic resonance method, 1g = 9.8m / s² 2The first segment has a resonant frequency of 20Hz to 50Hz, a mixing acceleration of 10g to 100g, and a mixing time of 1min to 5min; the second segment has a resonant frequency of 60Hz to 100Hz, a mixing acceleration of 110g to 200g, and a mixing time of 3min to 20min; the third segment has a resonant frequency of 40Hz to 70Hz, a mixing acceleration of 80g to 130g, and a mixing time of 1min to 10min; the purity of the nano-metal powder is greater than 99.9%.

[0007] In one possible implementation, the average particle size of the nano-metal powder is 50 nm to 100 nm, and the average particle size of the micron-sized non-metallic ceramic powder is 50 μm to 500 μm.

[0008] In one possible implementation, the mass ratio of the nano-metal powder to the micron-sized non-metallic ceramic powder is 1 to 2.

[0009] In one possible implementation, the nano-metal powder is Ni powder, and the micron-sized non-metallic ceramic powder is TiC powder or TiB2 powder.

[0010] In one possible implementation, the protective gas is nitrogen or an inert gas.

[0011] In one possible implementation, the volume ratio of the nano-metal powder to the micron-sized non-metallic ceramic powder in the mixing tank is 50% to 80%.

[0012] In one possible implementation, the absolute pressure inside the mixing tank is 50 kPa to 10 MPa, and the temperature of the tank body inside the mixing tank is... 10℃~100℃.

[0013] In one possible implementation, the cooling water in the mixing tank is tap water.

[0014] The present invention also provides a composite powder material for additive manufacturing, which is prepared by the above-described method for preparing composite powder materials for additive manufacturing.

[0015] In one possible implementation, the composite powder material has a core-shell structure, wherein the nano-metal powder coats the micron-sized non-metallic ceramic powder, and the thickness of the nano-metal powder coating layer is not less than 100 nm.

[0016] The beneficial effects of this invention are that, compared with the prior art, this invention achieves uniform coating of micron-sized ceramic powder with nano-metals under a protective atmosphere through a three-stage acoustic resonance method, effectively solving the problems of component segregation and poor interfacial bonding in traditional preparation methods, while avoiding the influence of high-temperature treatment on powder morphology. It has the advantages of improving the interfacial bonding quality of composite powders and the applicability of additive manufacturing, and solves the technical problem of poor interfacial bonding quality of metal-ceramic composite powders prepared by existing processes. Attached Figure Description

[0017] Figure 1 SEM image of a composite powder material prepared according to Example 1 of the present invention.

[0018] Figure 2 SEM image of the composite powder material prepared in Example 2 of this invention.

[0019] Figure 3 Metallographic image of a composite powder material prepared according to Example 1 of the present invention. Detailed Implementation

[0020] To address the aforementioned technical problems, this invention provides a composite powder material for additive manufacturing and its preparation method. The technical solution and embodiments of this invention will now be described in detail with reference to the accompanying drawings.

[0021] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly, for example, they can refer to fixed connection, detachable connection, or integral connection; for those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0024] In the traditional additive manufacturing process for ceramic-reinforced metal matrix composites, the insufficient interfacial bonding strength between the ceramic reinforcing phase and the metal matrix is ​​a particularly prominent issue. Due to the difference in wettability between the ceramic material and the aluminum alloy matrix, microcracks and porosity defects easily form at the interface between the reinforcing phase and the matrix, directly affecting the load transfer efficiency of the composite material. This phenomenon is even more pronounced under high temperature or cyclic loading conditions, where interfacial defects become stress concentration sources, leading to premature fracture failure of the material.

[0025] Faced with the aforementioned problems, this application first analyzes the physical mechanism of insufficient interfacial bonding strength, finding that traditional mechanical mixing methods cannot overcome the agglomeration effect caused by differences in the surface energy of ceramic particles. To address the problem of insufficient wettability of molten metal, this application attempts to employ surface modification technology, exploring two pathways: electroless nickel plating and physical coating. While electroless nickel plating can form a uniform metal layer, it suffers from complex processes and the potential to introduce impurity phases; while physical coating can maintain material purity, conventional ball milling processes easily damage the morphology of ceramic particles. By comparing different energy input methods, it is found that multi-frequency mechanical waves generated by acoustic resonance can simultaneously achieve powder dispersion and surface adsorption, with gradient acceleration control capable of overcoming van der Waals forces and electrostatic repulsion through stratification.

[0026] This invention provides a method for preparing composite powder materials for additive manufacturing, comprising the following steps: Nanoscale metal powder and micron-sized non-metallic ceramic powder are added to a mixing tank, a protective atmosphere is formed inside the mixing tank, and the gas pressure and temperature inside the tank are set. A three-stage acoustic resonance method is used for coating powder preparation, in which nanoscale metal powder is coated with micron-sized non-metallic ceramic powder to obtain a composite powder material with a core-shell structure.

[0027] In the three-segment acoustic resonance method, 1g = 9.8m / s² 2 The first segment has a resonant frequency of 20Hz to 50Hz, a mixing acceleration of 10g to 100g, and a mixing time of 1min to 5min; the second segment has a resonant frequency of 60Hz to 100Hz, a mixing acceleration of 110g to 200g, and a mixing time of 3min to 20min; the third segment has a resonant frequency of 40Hz to 70Hz, a mixing acceleration of 80g to 130g, and a mixing time of 1min to 10min; the purity of the nano-metal powder is greater than 99.9%.

[0028] The protective atmosphere refers to the oxygen-free or low-oxygen environment formed in the mixing tank, which can be achieved by replacing the air with nitrogen or inert gas to prevent the nano-metal powder from undergoing oxidation during the mixing process.

[0029] Among them, the three-stage acoustic resonance method refers to mixing in three stages with different frequencies and accelerations. The first stage uses low-frequency vibration of 20Hz to 50Hz to achieve initial dispersion, the second stage uses high-frequency vibration of 60Hz to 100Hz to promote the embedding of nanopowder, and the third stage uses mid-frequency vibration of 40Hz to 70Hz to complete the densification of the coating layer.

[0030] Among them, core-shell structured composite powder refers to a coating form with micron-sized ceramic particles as the core and a nano-metal layer as the outer shell. The interface bonding is achieved through the synergistic effect of electrostatic and mechanical forces, and the coating layer thickness is controlled by adjusting the mixing acceleration and time.

[0031] The gas pressure inside the tank is controlled within the range of 50 kPa to 10 MPa, which is specifically adjusted by a vacuum pump and a gas injection system. The high-pressure environment inhibits powder agglomeration and enhances the kinetic energy of particle collision.

[0032] The tank temperature is set from -10℃ to 100℃, and is maintained by cooling water circulation or heating device. Low temperature conditions reduce the surface activity of powder, while high temperature promotes metal plastic deformation to enhance the coating effect.

[0033] The core innovation of this application lies in the use of a three-stage acoustic resonance process parameter combination. Through a phased energy input method of low-frequency dispersion, high-frequency embedding, and mid-frequency densification, nano-metals are efficiently coated onto micron-sized ceramic particles under a protective atmosphere, forming a metallurgically bonded core-shell structure. This solves the problems of powder agglomeration and insufficient interfacial bonding in traditional mixing processes.

[0034] The present invention will now be described in detail through specific embodiments. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the following embodiments, unless otherwise specified, the methods described are conventional methods; and unless otherwise specified, the reagents and materials described are commercially available.

[0036] Example 1 This embodiment provides a method for preparing composite powder materials for additive manufacturing, including the following steps: Add 400g of nano-metal powder and 300g of micron-sized non-metallic ceramic powder to a 150ml PC mixing tank.

[0037] Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it to an absolute pressure of about 1 kPa. Then fill the tank with inert nitrogen until the absolute pressure reaches 0.1 MPa. The temperature inside the mixing tank is 33°C.

[0038] The three-stage acoustic resonance coating process parameters were set as follows: the first stage resonant frequency was 30Hz, the mixing acceleration was 40g, and the mixing time was 3min; the second stage resonant frequency was 60Hz, the mixing acceleration was 110g, and the mixing time was 15min; the third stage resonant frequency was 40Hz, the mixing acceleration was 90g, and the mixing time was 5min, thus obtaining a nickel-coated TiC composite powder material with a core-shell structure.

[0039] Among them, the micron-sized non-metallic ceramic powder is TiC with an average particle size of 100μm; the nano-metallic powder is nickel elemental powder with an average particle size of 50nm.

[0040] like Figure 1 The image shows an SEM image of the composite powder material prepared in this embodiment. It can be seen from the image that the nickel coating layer is uniformly and tightly adhered to the TiC particles.

[0041] Example 2 This embodiment provides a method for preparing composite powder materials for additive manufacturing, including the following steps: Add 400g of nano-metal powder and 300g of micron-sized non-metallic ceramic powder to a 150ml PC mixing tank.

[0042] Place the mixing tank on the Hummingbird Acoustic Resonance Mixer HAM500 and evacuate it to an absolute pressure of about 1 kPa. Then fill the tank with inert nitrogen until the absolute pressure reaches 0.1 MPa. The temperature inside the mixing tank is 33°C.

[0043] The three-stage acoustic resonance coating process parameters were set as follows: the first stage resonant frequency was 30Hz, the mixing acceleration was 40g, and the mixing time was 3min; the second stage resonant frequency was 60Hz, the mixing acceleration was 110g, and the mixing time was 15min; the third stage resonant frequency was 40Hz, the mixing acceleration was 90g, and the mixing time was 5min, thus obtaining a nickel-coated TiB2 composite powder material with a core-shell structure.

[0044] Among them, the micron-sized non-metallic ceramic powder is TiB2 with an average particle size of 100μm; the nano-metallic powder is nickel elemental powder with an average particle size of 50nm.

[0045] like Figure 2 The SEM image of the composite powder material prepared in this embodiment shows that the nickel coating layer is uniformly and tightly adhered to the TiB2 particles.

[0046] SEM testing: A Hitachi S-4800 field emission scanning electron microscope was used, and the testing conditions were an accelerating voltage of 5kV.

[0047] Metallographic testing: Metallographic observation was performed using an automatic metallographic sample grinding and polishing machine (model: YMPZ-1-250) and a LEICA DMI3000M metallographic microscope. The results are as follows: Figure 3 As shown.

[0048] The above description is merely a preferred embodiment of the present invention, and the specific embodiments described above are not intended to limit the present invention. Various modifications and variations can be made within the scope of the technical concept of the present invention. All refinements, modifications, or equivalent substitutions made by those skilled in the art based on the above description are within the scope of protection of the present invention.

Claims

1. A method for preparing composite powder materials for additive manufacturing, characterized in that, Includes the following steps: Nano-metal powder and micron-sized non-metallic ceramic powder are added to a mixing tank to form a protective atmosphere. The gas pressure and temperature inside the tank are set, and a three-stage acoustic resonance method is used for coating powder preparation. Nano-metal powder is coated with micron-sized non-metallic ceramic powder to obtain a composite powder material with a core-shell structure. In the three-segment acoustic resonance method, 1g = 9.8m / s² 2 The first segment has a resonant frequency of 20Hz to 50Hz, a mixing acceleration of 10g to 100g, and a mixing time of 1min to 5min; the second segment has a resonant frequency of 60Hz to 100Hz, a mixing acceleration of 110g to 200g, and a mixing time of 3min to 20min; the third segment has a resonant frequency of 40Hz to 70Hz, a mixing acceleration of 80g to 130g, and a mixing time of 1min to 10min. The purity of the nano-metal powder is greater than 99.9%.

2. The preparation method according to claim 1, characterized in that, The average particle size of the nano-metal powder is 50 nm to 100 nm, and the average particle size of the micron-sized non-metallic ceramic powder is 50 μm to 500 μm.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the nano-metal powder to the micron-sized non-metallic ceramic powder is 1 to 2.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The nano-metal powder is Ni powder, and the micron-sized non-metallic ceramic powder is TiC powder or TiB2 powder.

5. The preparation method according to claim 1, characterized in that, The protective gas is nitrogen or an inert gas.

6. The preparation method according to claim 1, characterized in that, The volume ratio of the nano-metal powder to the micron-sized non-metallic ceramic powder in the mixing tank is 50% to 80%.

7. The preparation method according to claim 1, characterized in that, The absolute pressure inside the mixing tank is 50 kPa to 10 MPa, and the temperature inside the mixing tank is... 10℃~100℃.

8. The preparation method according to claim 1, characterized in that, The cooling water in the mixing tank is tap water.

9. A composite powder material for additive manufacturing, characterized in that, The composite powder material for additive manufacturing is prepared by any one of claims 1 to 8.

10. The composite powder material according to claim 9, characterized in that, The composite powder material has a core-shell structure, wherein the nano-metal powder coats the micron-sized non-metallic ceramic powder, and the thickness of the nano-metal powder coating layer is not less than 100 nm.

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