Tantalum alloy metal powder suitable for metal additive manufacturing and preparation method thereof

Abstract

The invention discloses tantalum alloy metal powder suitable for metal additive manufacturing and a preparation method of the tantalum alloy metal powder, and relates to the technical field of additive manufacturing. According to the preparation method, the tantalum powder is treated by utilizing the cationic surfactant, the active particles are treated by utilizing the anionic surfactant, and then the self-assembled active composite powder is synthesized by utilizing electrostatic interaction between different positive and negative charges, so that the prepared tantalum alloy spherical powder still keeps good sphericity; not only are the sphericity and fluidity of the powder almost not affected, but also a good metallurgical reaction between micro-nano particles and a matrix in an additive manufacturing formed part can be promoted, and various tantalum alloy high-performance materials needed by a user are promoted to be formed.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and more particularly to tantalum alloy metal powders suitable for metal additive manufacturing and a method for preparing the same. Background Art

[0002] As an advanced metal material with excellent high-temperature performance, corrosion resistance and good mechanical properties, tantalum alloys are widely used in the fields of aerospace, nuclear energy, electronics manufacturing, chemical engineering and national defense, and play an irreplaceable role especially under high temperature, corrosion and mechanical load in extreme environments. With the continuous increase in the demand for structural lightweight and structure-function integration design, the research and development of tantalum alloy materials face higher challenges. In particular, while reducing the overall weight and improving the comprehensive performance, it is necessary to develop technologies suitable for high-performance and lightweight tantalum alloys.

[0003] Traditional methods for preparing tantalum alloys, such as powder metallurgy and melting, can obtain materials with certain properties, but these methods often have problems such as complex processes, high costs and long cycles, and the properties of the materials may not meet high-standard requirements in different application scenarios. For example, some tantalum alloy materials are improved in mechanical strength and corrosion resistance by adding refractory metal elements such as tungsten and niobium, and large deformation is caused by rolling and then the alloy grain size is optimized by high-temperature treatment or other heat treatment processes. However, these treatment processes are often complex and time-consuming, resulting in limited effects on subsequent performance improvement. Taking the tantalum alloy patent with publication number CN116855807A as an example, this patent obtains a composite powder by vacuum mixing tantalum powder and tungsten powder according to a ratio, then sintering and forming the composite powder loaded into a mold, and then performing cold rolling and finally vacuum heat treatment annealing. The tantalum alloy prepared by the above process has fine grains and good properties. Although this method has made certain progress in some fields, it still faces challenges such as high cost, long cycle and complex post-treatment.

[0004] In the research and development process of tantalum alloys, traditional preparation methods usually require high-temperature treatment to ensure the high strength and high hardness of tantalum alloys, but this process is complex and energy-consuming, and has a greater impact on the environment. Therefore, in order to better solve these problems, researchers have begun to explore the application of additive manufacturing technology in tantalum alloy materials. Additive manufacturing technology can not only achieve rapid forming of complex structures, but also improve the design flexibility and process controllability of tantalum alloys on the basis of ensuring their high strength and high thermal conductivity. Relevant research shows that the additive manufacturing process of tantalum alloys, especially through laser 3D printing technology, can effectively avoid problems such as powder forming and cold welding in traditional methods, improve the fluidity of powders and the uniformity of particles, and can precisely control the microstructure of the alloy during the forming process, thereby improving the comprehensive performance of tantalum alloys.

[0005] However, although additive manufacturing technology has shown great potential in the preparation of tantalum alloy materials, it still faces several challenges in practical applications. For example, in the process of preparing tantalum alloy powder, there are problems such as irregular powder shape and strong surface activity. These factors not only affect the fluidity and processability of the powder, but also may lead to the appearance of microdefects during the forming process, thus affecting the mechanical properties and corrosion resistance of the finished product. Therefore, how to develop tantalum alloy powder with high activity, easy preparation and high sphericity suitable for additive manufacturing is a technical problem that needs to be solved urgently at present.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide a tantalum alloy metal powder for metal additive manufacturing and its preparation method, aiming to provide tantalum alloy powder with high activity, easy preparation and high sphericity for additive manufacturing.

[0008] The present invention is implemented as follows:

[0009] In the first aspect, the present invention provides a preparation method for a tantalum alloy metal powder suitable for metal additive manufacturing, including:

[0010] Mix pure tantalum powder and a cationic surfactant solution, and separate to obtain modified tantalum powder;

[0011] Mix active particles and an anionic surfactant solution, and separate to obtain modified active particles; wherein, the material of the active particles is selected from at least one of Cu, Al, Si, Ti, Y, Mg, Zn and their oxides;

[0012] Mix and react the modified tantalum powder and the modified active particles in a reaction solvent, and separate to obtain a self-assembled active composite powder.

[0013] In an optional embodiment, during the process of preparing the modified tantalum powder, the cationic surfactant in the cationic surfactant solution is selected from at least one of (3-aminopropyl)triethoxysilane, alkyltrimethylammonium chloride, alkylammonium chloride and alkylmethylammonium chloride; preferably (3-aminopropyl)triethoxysilane;

[0014] The dosage of tantalum powder corresponding to 1L of cationic surfactant is 1g - 50g, and it is selected as 5g - 30g;

[0015] The particle size of the tantalum powder is 15μm - 150μm, and it is selected as 15μm - 53μm.

[0016] In an optional embodiment, the process of preparing the modified tantalum powder includes: mixing and stirring the tantalum powder and the cationic surfactant solution, and then performing multiple filtrations and washings;

[0017] The dispersion solvent and the washing solvent of the cationic surfactant solution are each independently selected from at least one of aqueous ethanol solution, tetrahydrofuran, dimethylformamide, and diethyl ether.

[0018] In an alternative embodiment, during the preparation of the modified active particles, the anionic surfactant in the anionic surfactant solution is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyacrylamide, and α-olefin sulfonic acid, and is selected as sodium dodecyl sulfate;

[0019] The mass ratio of the anionic surfactant to the active particles is 1:(0.3 - 2.0), and the concentration of the anionic surfactant in the anionic surfactant solution is 0.5 g / L - 1.5 g / L;

[0020] The particle size of the active particles is 50 nm - 500 nm.

[0021] In an alternative embodiment, the process for preparing the modified active particles includes: subjecting the active particles to surface pickling and then mixing and stirring with the anionic surfactant solution, followed by filtration and washing;

[0022] The pickling solution used in the surface pickling process is selected from at least one of dilute hydrochloric acid and dilute nitric acid, and the mass fraction of the pickling solution is 0.1% - 10%;

[0023] The dispersion solvent and the washing solvent of the anionic surfactant solution are each independently selected from at least one of tetrahydrofuran, dimethylformamide, and diethyl ether.

[0024] In an alternative embodiment, the process for preparing the self-assembled active composite powder includes: mixing the modified tantalum powder with a first reaction solvent to obtain a first mixture, mixing the modified active particles with a second reaction solvent to obtain a second mixture, mixing and stirring the first mixture and the second mixture for 30 min - 60 min, and then performing solid-liquid separation;

[0025] The mass ratio of the modified active particles to the modified tantalum powder is 1:(40 - 50);

[0026] The mixing and stirring method of the first mixture and the second mixture is selected from at least one of vibration stirring and ultrasonic stirring;

[0027] The first reaction solvent is selected from at least one of aqueous ethanol solution, tetrahydrofuran, dimethylformamide, and diethyl ether; the second reaction solvent is selected from at least one of tetrahydrofuran, dimethylformamide, and diethyl ether;

[0028] Solid-liquid separation is carried out by vacuum filtration, and the vacuum pressure is controlled to be 0.1 bar - 5.0 bar.

[0029] In an alternative embodiment, the self-assembled active composite powder is freeze-dried to obtain a tantalum alloy powder with nano-active powder uniformly loaded on its surface;

[0030] Control the freeze-drying temperature to be -80°C to -10°C, the drying duration to be 2h - 10h, and then heat it to room temperature at a heating rate of 1°C / h - 50°C / h;

[0031] In an alternative embodiment, it further includes: drying the powder after surface treatment;

[0032] The powder after surface treatment is dried by vacuum drying, and the temperature of the vacuum drying is controlled to be 50°C - 200°C, and the pressure is 0.1 bar - 5 bar.

[0033] In a second aspect, the present invention provides a tantalum alloy metal powder suitable for metal additive manufacturing, which is prepared by the preparation method of any one of the foregoing embodiments.

[0034] In a third aspect, the present invention provides the application of the tantalum alloy metal powder of the foregoing embodiment in additive manufacturing;

[0035] The process of preparing a tantalum alloy using the tantalum alloy metal powder includes: setting the processing path of additive manufacturing according to the set three-dimensional model, and using a laser additive manufacturing process to process and form a target solid part.

[0036] The present invention has the following beneficial effects: The present invention uses a cationic surfactant to treat tantalum powder and an anionic surfactant to treat active particles, and then synthesizes a self-assembled active composite powder by the electrostatic interaction between different positive and negative charges. The prepared spherical tantalum alloy powder still maintains good sphericity, which not only has little impact on the sphericity and fluidity of the powder, but also can promote the good metallurgical reaction between micro-nano particles and the matrix in the additive manufacturing formed part, and promote the formation of various high-performance tantalum alloy materials required by users. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a flowchart for preparing spherical powder for high-active metal additive manufacturing based on molecular self-assembly;

[0039] Figure 2It is the characterization diagram of the Cu / Ta powder prepared in Example 1; (a) represents the SEM diagram, and (b) represents the EDS test diagram;

[0040] Figure 3 It is the characterization diagram of the Cu / Ta powder prepared in Example 2; (a) represents the SEM diagram, and (b) represents the EDS test diagram;

[0041] Figure 4 It is the microstructure diagram of the alloy prepared by SLM in Examples 1 and 3; (a) represents Example 1, and (b) represents Example 3;

[0042] Figure 5 It is the particle size distribution diagram of the copper powder used in Examples 1 and 3; (a) represents the nano copper powder used in Example 1; (b) represents the micro copper powder used in Example 3;

[0043] Figure 6 It is the characterization diagram of the tantalum alloy metal powder prepared in Example 5; (a) represents the SEM diagram, and (b) and (c) represent the EDS test diagrams;

[0044] Figure 7 It is the microstructure of the nano Y2O3 / Ta tantalum alloy composite material prepared by SLM in Example 5; (a) and (b) represent different magnification factors;

[0045] Figure 8 It is the characterization diagram of the tantalum alloy metal powder prepared in Example 6; (a) represents the SEM diagram, and (b) and (c) represent the EDS test diagrams;

[0046] Figure 9 It is the microstructure of the nano TiO2 / Ta tantalum alloy composite material prepared by SLM in Example 6; (a) and (b) represent different magnification factors. Detailed implementation manners

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For those reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0048] Due to problems such as irregular powder shape and strong surface activity in the preparation process of tantalum alloy powder in the prior art, these factors not only affect the fluidity and processability of the powder, but may also lead to the appearance of micro-defects during the forming process, thereby affecting the mechanical properties and corrosion resistance of the additive manufactured products of tantalum alloy powder. In view of this, the present invention improves the preparation process of tantalum alloy powder and synthesizes a new type of powder by using the electrostatic interaction between different positive and negative charges.

[0049] The present invention provides a method for preparing tantalum alloy metal powder suitable for metal additive manufacturing, such as Figure 1 As shown, the steps are as follows:

[0050] S1. Preparation of modified tantalum powder

[0051] Tantalum powder (i.e., micron-sized spherical tantalum powder A) and a cationic surfactant solution are mixed, fully mixed and stirred to ensure uniform dispersion, and then the modified tantalum powder is separated, so that the surface of the modified tantalum powder is positively charged. The separation method is not limited, and can be a common filtering and washing method, and can be filtered and washed multiple times to remove excess reaction products.

[0052] In some embodiments, the tantalum powder is a spherical micron-sized tantalum powder A, and the particle size of the tantalum powder is 15 μm-150 μm, preferably 15 μm-53 μm, such as 15 μm, 20 μm, 30 μm, 40 μm, 53 μm, 70 μm, 100 μm, 120 μm, 150 μm, etc. The purity of the tantalum powder can reach 99.00 wt.%, and it is purchased from Stardust Technology Co., Ltd.

[0053] In some embodiments, the cationic surfactant in the cationic surfactant solution is selected from at least one of (3-aminopropyl) triethoxysilane, alkyl trimethyl ammonium chloride, alkyl ammonium chloride and alkyl methyl ammonium chloride. The cationic surfactant may be any one or more of the above, and the above cationic surfactants can charge the surface of the tantalum powder well. The cationic surfactant is selected from (3-aminopropyl) triethoxysilane and alkyl methyl ammonium chloride for comparison. The self-assembly effect of (3-aminopropyl) triethoxysilane is better, so that the sphericity of the tantalum alloy powder is better and the mechanical properties are more outstanding.

[0054] Furthermore, the amount of tantalum powder corresponding to 1L of cationic surfactant is 1g-50g, such as 1g, 5g, 10g, 20g, 30g, 40g, 50g, etc. The specific amount of cationic surfactant is mainly determined based on the dispersion effect of the powder in the reagent, such as whether there is obvious agglomeration, reaction, etc. Under the condition of uniform dispersion, in order to improve the activation rate, the amount of tantalum powder corresponding to 1L of cationic surfactant is 5g-30g.

[0055] In some embodiments, the dispersing solvent and the washing solvent of the cationic surfactant solution are independently selected from at least one of ethanol aqueous solution, tetrahydrofuran, dimethylformamide and diethyl ether, and are selected from at least one of ethanol aqueous solution, dimethylformamide and diethyl ether.

[0056] S2. Preparation of modified active particles

[0057] The active particles (i.e., nanoscale active particles B) and the anionic surfactant solution are fully mixed and stirred, and then the modified active particles with a negatively charged surface are obtained by separation. The separation method is not limited and can be common filtration and washing methods.

[0058] Among them, the material of the active particles is selected from at least one of Cu, Al, Si, Ti, Y, Mg, Zn and their oxides. The material of the active particles can be any one or several of the above, and is selected as at least one of Cu, Al, Zn, Si and Ti. Just select the appropriate active particles according to the material of the alloy product to be prepared. The active particles are nanoscale, with a particle size of 50nm - 500nm, such as 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, etc. The purity of the active particles can be 99.00wt.%, but is not limited thereto.

[0059] In some embodiments, during the preparation of the modified active particles, the anionic surfactant in the anionic surfactant solution is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyacrylamide and α-olefin sulfonic acid. The anionic surfactant can be any one or several of the above. The anionic surfactant is selected as sodium dodecyl sulfate, and the self-assembly effect of using this anionic surfactant is better, making the sphericity and fluidity of the tantalum alloy powder better.

[0060] Furthermore, the mass ratio of the anionic surfactant to the active particles is 1:(0.3 - 2.0), such as 1:0.3, 1:0.5, 1:1.0, 1:1.5, 1:2.0, etc.; the concentration of the anionic surfactant in the anionic surfactant solution is 0.5g / L - 1.5g / L, such as 0.5g / L, 1.0g / L, 1.5g / L, etc. Mainly according to the dispersion effect of the powder in the reagent, such as whether there are obvious agglomeration, reaction and other phenomena, the dosage of the anionic surfactant is adjusted. Under the condition of ensuring uniform dispersion, in order to improve the activation rate, the selected dosage of the active particles corresponding to 1L of the anionic surfactant is 0.5g - 2g.

[0061] In some embodiments, the process of preparing the modified active particles includes: pickling the surface of the active particles and then fully mixing and stirring with the anionic surfactant solution, and then filtering and washing. Since the active particles are nanoscale, there is an electrostatic adsorption force on their own and they are prone to agglomeration. By pickling, the electrostatic adsorption force can be eliminated, and it is easier to disperse evenly and then fully stir and mix with the anionic surfactant.

[0062] Further, the pickling solution used in the surface pickling process is a weak acid, selected from at least one of dilute hydrochloric acid and dilute nitric acid, and selected as dilute hydrochloric acid, which can better disperse the nanoparticles. The mass fraction of the pickling solution is 0.1%-10%, and the mass fraction can be, for example, 0.1%, 0.5%, 1.0%, 3.0%, 5.0%, 8.0%, 10.0%, etc.

[0063] In some embodiments, the dispersion solvent and the washing solvent of the anionic surfactant solution are each independently selected from at least one of tetrahydrofuran, dimethylformamide, and diethyl ether. The dispersion solvent and the washing solvent can be the same or different, and can each independently be selected from any one or several of the above. The dispersion solvent and the washing solvent of the anionic surfactant solution are each independently selected from at least one of dimethylformamide and diethyl ether.

[0064] S3. Self-assembly

[0065] Mix the modified tantalum powder and the modified active particles in a reaction solvent and react, and then separate to obtain the self-assembled active composite powder. Through the methods of step S1 and step S2, nanoparticles and micron-sized metal powders can be effectively attached with positive / negative charges through surface modification, prompting the nano-active particles to in-situ, uniformly and quantitatively wrap on the surface of the micron-sized metal spheres through Van der Waals force, realizing the personalized and customized preparation of tantalum alloy powder.

[0066] In some embodiments, the process of preparing the self-assembled active composite powder includes: mixing and standing the modified tantalum powder and the first reaction solvent to obtain a first mixed solution, mixing and standing the modified active particles and the second reaction solvent to obtain a second mixed solution, mixing the first mixed solution and the second mixed solution, stirring the suspension solution for 30 min - 60 min, and then separating the solid from the liquid. The mass ratio of the modified active particles to the modified tantalum powder is 1:(40 - 50), and within this range, a composite active tantalum alloy powder suitable for additive manufacturing can be prepared.

[0067] Specifically, the second mixed solution with nanoscale particles can be poured into the first mixed solution with micron-scale particles. The mass ratio of the modified active particles to the modified tantalum powder can be 1:40, 1:43, 1:45, 1:48, 1:50, etc.

[0068] Further, the mixing and stirring method of the first mixed solution and the second mixed solution is selected from at least one of vibration stirring and ultrasonic stirring, and ultrasonic stirring is selected to improve the mixing uniformity. The first reaction solvent is selected from at least one of ethanol aqueous solution, tetrahydrofuran, dimethylformamide, and diethyl ether, and the first reaction solvent can be any one or several of the above; the second reaction solvent is selected from at least one of tetrahydrofuran, dimethylformamide, and diethyl ether, and the second reaction solvent can be any one or several of the above.

[0069] In some embodiments, solid-liquid separation can be carried out by vacuum filtration, and the vacuum pressure is controlled to be 0.1 bar - 5.0 bar, such as 0.1 bar, 0.5 bar, 1.0 bar, 2.0 bar, 3.0 bar, 4.0 bar, 5.0 bar, etc., and it is selected to be 0.5 bar - 2.0 bar.

[0070] S4. Freeze-drying, vacuum drying

[0071] The self-assembled active composite powder is freeze-dried. In some embodiments, the freeze-drying temperature is controlled to be -80°C to -10°C (selected to be -50°C to -20°C), the drying duration is 2 h - 10 h (selected to be 3 h - 8 h), and then it is slowly heated to room temperature at a heating rate of 1°C / h - 50°C / h (selected to be 5°C / h - 20°C / h), and then taken out for standby. Specifically, the freeze-drying temperature can be -80°C, -70°C, -60°C, -50°C, -40°C, -30°C, -20°C, -10°C, etc.; the drying duration can be 2 h, 3 h, 5 h, 8 h, 10 h, etc.; the heating rate can be 1°C / h, 5°C / h, 10°C / h, 20°C / h, 30°C / h, 40°C / h, 50°C / h, etc.

[0072] Furthermore, the powder after surface treatment is dried to further remove the residual solvent on the surface. The powder after surface treatment can be dried by vacuum drying, and the temperature of vacuum drying is controlled to be 50°C - 200°C (selected to be 80°C - 120°C), such as 50°C, 80°C, 100°C, 130°C, 150°C, 180°C, 200°C, etc.; the pressure is 0.1 bar - 5 bar (selected to be 0.8 bar - 1.2 bar), such as 0.1 bar, 0.8 bar, 1.0 bar, 1.2 bar, 1.0 bar, 2.0 bar, 3.0 bar, 4.0 bar, 5.0 bar, etc.

[0073] The embodiment of the present invention also provides a tantalum alloy metal powder suitable for metal additive manufacturing, which is prepared by the preparation method provided by the embodiment of the present invention.

[0074] It should be noted that the preparation method provided by the embodiments of the present invention has the following advantages: (1) The tantalum alloy powder preparation method proposed by the present invention is conducive to reducing problems such as powder deformation and decreased sphericity caused by mechanical mixing of micro-nano particles / metal powders, and also avoids phenomena such as nanoparticle agglomeration that easily occur during the mixing of micro-nano particles / metal powders. The spherical tantalum alloy powder prepared by the present invention still maintains good sphericity, which not only has little impact on the sphericity and fluidity of the powder, but also promotes good metallurgical reactions between micro-nano particles and the matrix in the SLM formed parts, enabling the formation of various high-performance tantalum alloy materials required by users. (2) Since it can in-situ and quantitatively modify a layer of other highly active materials on the surface of highly active tantalum alloy powder, it is an excellent method that can simply and easily realize the concepts of material designers. (3) The method proposed by the present invention solves the problem that various highly active materials can only obtain the desired tantalum alloy powder through alloy ratio, smelting, casting and a series of powder-making processes.

[0075] The tantalum alloy metal powder provided by the embodiments of the present invention can be used to prepare tantalum alloy by additive manufacturing. After using laser additive manufacturing technology to prepare the manufactured powder, the improvement of the SLM alloy in different mechanical properties is realized, and in some aspects, it has even far exceeded the level of casting materials with similar chemical compositions, indicating that it can be regarded as an excellent preparation method for obtaining metal alloy powder for additive manufacturing, and at the same time, it is also a good manufacturing method suitable for high-performance alloy materials.

[0076] In the actual operation process, the process of preparing tantalum alloy using tantalum alloy metal powder includes: setting the processing path of additive manufacturing according to the set three-dimensional model, and using laser additive manufacturing technology to process and form the target solid part.

[0077] Specifically, the three-dimensional modeling software can be special modeling software such as UG, Solidworks, CATIA, etc. The scanning path is to convert the information in the three-dimensional model into multiple slices, and each slice is defined as the cross-sectional layer of the part, and then the above method is used to manufacture the solid.

[0078] The parts manufactured by additive manufacturing are processed by a series of additive manufacturing technologies. This series of additive manufacturing processes includes: electron beam additive manufacturing (EBAM), direct metal deposition (DMD), direct metal laser sintering (DMLS), laser near-net shaping (LENS), laser metal forming (LMF), selective laser melting (SLM), selective laser sintering (SLS), supersonic cold spraying (CS), etc. The selective laser melting (SLM) and laser near-net shaping (LENS) technologies are selected.

[0079] The features and performance of the present invention will be further described in detail below in conjunction with embodiments.

[0080] Example 1

[0081] This example provides a method for preparing tantalum alloy metal powder suitable for metal additive manufacturing. Irregular nano pure Cu particles (99.9 wt.%) with an average particle size of 500 nm and spherical gas-atomized pure Ta powder with a particle size range of 15 - 53 μm are selected. Sodium dodecyl sulfate is selected as the anionic surfactant, and (3-aminopropyl)triethoxysilane is selected as the cationic surfactant. Then, according to Figure 1 the preparation sequence of the spherical powder shown, 2 wt.% of nano pure Cu particles are weighed, and the surface of 98 wt.% of pure Ta powder is modified to manufacture composite powder. The specific operation steps are as follows:

[0082] (1) Surface modification of pure Ta powder with (3-aminopropyl)triethoxysilane respectively: Add 50 g of pure Ta powder to 2 L of ethanol aqueous solution (1:1) and stir for 10 minutes to ensure its uniform dispersion. Then, pour 1 L of (3-aminopropyl)triethoxysilane solvent into the suspension respectively. After fully mixing at room temperature for 1 hour, amine-functionalized pure Ta powder can be obtained, that is, a layer of positive charge is carried on the powder surface. After filtering the product, wash it 3 times with ethanol and deionized water to remove the remaining reactants. Subsequently, the pure Ta powder surface-modified with (3-aminopropyl)triethoxysilane is redispersed in 3 L of deionized water respectively. Finally, use an ultrasonic device to process the above suspension for 30 minutes.

[0083] (2) Disperse nano pure Cu particles with sodium dodecyl sulfate solvent: After washing 1 g of nano pure Cu powder 3 times with 0.1 wt% dilute hydrochloric acid, add it to 1 L of deionized water. After mixing evenly, add 1 g of sodium dodecyl sulfate powder to make an anionic surfactant solution, and ultrasonically stir this solution for 30 minutes. After filtering, wash it three times with dimethylformamide to remove the remaining unreacted cationic surfactant.

[0084] (3) Modify pure Ta powder on the surface of nano pure Cu particles: Slowly pour the nano pure Cu particle suspension into the pure Ta powder suspension. After stirring the above mixed suspension for 1 hour, filter and collect the pure Ta powder modified on the surface of nano pure Cu under a vacuum pressure of 1 bar. Put the obtained product into a drying oven and freeze-dry it at -35 °C for 5 hours, and then store it at room temperature (about 20 - 25 °C).

[0085] The morphology and element distribution of the treated powder are as Figure 2 shown.

[0086] (4) Composite powder storage and additive manufacturing: Put the collected composite powder into a vacuum drying oven, evacuate to a pressure of about 120 MPa, heat to 120 °C at a heating rate of 80 °C / min, keep warm for 2 hours and then carry out vacuum drying. The alloy powder obtained after drying is put into a vacuum bag and evacuated for storage for later use. Then, pour the nano Cu / Ta alloy composite powder into the powder storage bin of a Selective Laser Melting (SLM) additive manufacturing system and wait for selective laser melting forming.

[0087] The SLM process parameters in Example 1 are as follows: Use an EOS M290 system to manufacture the alloy material and detect its friction and wear performance. The specific process parameters are: laser spot is 100 μm, laser power is 240 W, layer thickness is 20 μm, scan spacing is 80 μm, and scan speed is 660 mm / s.

[0088] It should be noted that the process involved in the additive manufacturing system in step (5) can also specifically select any one of the technologies such as Electron Beam Additive Manufacturing (EBAM), Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS), Laser Engineered Net Shaping (LENS), Laser Metal Forming (LMF), Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Supersonic Cold Spray (CS), etc. However, in the present invention, selective laser melting (SLM) and laser engineered net shaping (LENS) technologies are selected.

[0089] Example 2

[0090] The difference from Example 1 is only that the cationic surfactant (3-aminopropyl) triethoxysilane is replaced by alkyl methyl ammonium chloride.

[0091] Example 3

[0092] The difference from Example 1 is only that the pure Cu particles are in the micron level, and the specific particle size is 30 microns.

[0093] Example 4

[0094] The difference from Example 2 is only that the pure Cu particles are in the micron level, and the specific particle size is 30 microns.

[0095] Example 5

[0096] This example provides a micro-nano structured high-activity spherical tantalum alloy. The difference in its preparation method from that of Example 1 is that 1 g of Cu is replaced by 1 g of Y2O3.

[0097] Example 6

[0098] This embodiment provides a highly active spherical tantalum alloy with micro-nano structure. The difference in its preparation method from that of Embodiment 1 lies in that 1 g of Cu is replaced by 1 g of TiO₂.

[0099] Comparative Example 1

[0100] A mixed powder of micron-sized copper and tantalum prepared by the planetary ball milling method, with the following ball-to-powder ratio: 7:3, mixing time: 8 h, and mixing rotation speed: 150 rpm.

[0101] The results show that in Embodiment 1, the nano copper and micron tantalum powders are well mixed, and the nano copper is adsorbed on the surface of the pure tantalum powder. Tantalum-copper alloys are prepared using micron copper and nano copper respectively. Among them, the nano copper powder is evenly distributed, and the tantalum-copper microstructure is fine and the composition distribution is uniform under SEM. However, cracks appear in the tantalum-copper prepared from the mixed powder of micron copper and tantalum prepared by the planetary ball milling method in the comparative example, which indicates that there are certain difficulties in the homogenization of tantalum-copper by the mechanical mixing method.

[0102] In addition, the addition of Cu plays a role in solid solution strengthening. The Vickers hardness of pure tantalum and tantalum-copper is shown in Table 1. Among them, the hardness increases by nearly 40 HV after the addition of nano copper compared with pure tantalum, and the hardness increases by about 20 HV after the addition of nano copper compared with the addition of micron copper, and the performance is significantly improved.

[0103] Table 1 Average hardness of tantalum and tantalum alloys prepared by SLM

[0104]

[0105] Figure 2 is the nano Cu / Ta powder treated with (3-aminopropyl)triethoxysilane cationic surfactant, Figure 3 is the nano Cu / Ta powder treated with alkylmethylammonium chloride cationic surfactant. Figure 3 It shows that no nano Cu particles are detected attached to the small Ta powder, proving that the self-assembly effect of Ta powder treated with alkylmethylammonium chloride cationic surfactant is average, the powder mixing is uneven, resulting in a decrease in microhardness.

[0106] The microstructures of nano Cu / Ta (Embodiment 1) and micron Cu / Ta (Embodiment 3) prepared by SLM are as Figure 4 shown. It can be seen that after using nano Cu powder, the microstructure of the Ta alloy is refined, while significant cracks appear in the Ta-Cu alloy prepared using micron Cu powder. This may be related to the uneven mixing of Ta and Cu powders at the micron level, the element separation during the preparation of the bulk, and when the Cu melt solidifies rapidly, Ta may hinder its uniform shrinkage, forming microcracks at the grain boundaries or around the particles.

[0107] The particle sizes of the copper powders used in Embodiment 1 and Embodiment 3 are as Figure 5 shown.

[0108] The characterization diagram of the tantalum alloy metal powder prepared in Example 5 is as Figure 6 shown. Nanoscale Y2O3 is uniformly distributed on the Ta surface. The microstructure of the nanoscale Y2O3 / Ta tantalum alloy composite prepared by SLM is as Figure 7 .

[0109] The SEM diagram of the tantalum alloy metal powder prepared in Example 6 is as Figure 8 shown. Nanoscale Y2O3 is uniformly distributed on the Ta surface. The microstructure of the nanoscale TiO2 / Ta tantalum alloy composite prepared by SLM is as Figure 9 .

[0110] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing tantalum alloy metal powder suitable for metal additive manufacturing, characterized in that: include: Tantalum powder and a cationic surfactant solution are mixed and separated to obtain modified tantalum powder; The active particles and anionic surfactant solution are mixed and separated to obtain modified active particles; wherein the material of the active particles is selected from at least one of Cu, Al, Si, Ti, Y, Mg, Zn and oxides thereof; The modified tantalum powder and the modified active particles are mixed in a reaction solvent for reaction, and separated to obtain a self-assembled active composite powder.

2. The preparation method according to claim 1, characterized in that: In the process of preparing the modified tantalum powder, the cationic surfactant in the cationic surfactant solution is selected from at least one of (3-aminopropyl)triethoxysilane, alkyltrimethylammonium chloride, alkylammonium chloride and alkylmethylammonium chloride; The amount of the cationic surfactant corresponding to 1L of the tantalum powder is 1g-50g; And / or, the particle size of the tantalum powder is 15 μm-150 μm.

3. The preparation method according to claim 1 or 2, characterized in that: The process of preparing the modified tantalum powder comprises: mixing and stirring the tantalum powder and the cationic surfactant solution, and then filtering and washing for multiple times; The dispersing solvent and washing solvent of the cationic surfactant solution are independently selected from at least one of ethanol aqueous solution, tetrahydrofuran, dimethylformamide and diethyl ether.

4. The preparation method according to claim 1, characterized in that: In the process of preparing the modified active particles, the anionic surfactant in the anionic surfactant solution is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, polyacrylamide and α-olefin sulfonic acid; The mass ratio of the anionic surfactant to the active particles is 1:(0.3-2.0), and the concentration of the anionic surfactant in the anionic surfactant solution is 0.5 g / L-1.5 g / L; The particle size of the active particles is 50nm-500nm.

5. The preparation method according to claim 1 or 4, characterized in that: The process of preparing the modified active particles comprises: washing the surface of the active particles with acid, mixing and stirring with the anionic surfactant solution, and then filtering and washing; The pickling solution used in the surface pickling process is selected from at least one of dilute hydrochloric acid and dilute nitric acid, and the mass fraction of the pickling solution is 0.1%-10%; The dispersing solvent and the washing solvent of the anionic surfactant solution are independently selected from at least one of tetrahydrofuran, dimethylformamide and diethyl ether.

6. The preparation method according to claim 1, characterized in that: The process of preparing the self-assembled active composite powder comprises: mixing the modified tantalum powder and the first reaction solvent to obtain a first mixed solution, mixing the modified active particles and the second reaction solvent to obtain a second mixed solution, mixing the first mixed solution and the second mixed solution for 30 minutes to 60 minutes, and then separating the solid and the liquid; The mass ratio of the modified active particles to the modified tantalum powder is 1:(40-50); The mixing and stirring method of the first mixed liquid and the second mixed liquid is selected from at least one of vibration stirring and ultrasonic stirring; The first reaction solvent is selected from at least one of ethanol aqueous solution, tetrahydrofuran, dimethylformamide and diethyl ether; the second reaction solvent is selected from at least one of tetrahydrofuran, dimethylformamide and diethyl ether; Vacuum filtration is used for solid-liquid separation, and the vacuum pressure is controlled at 0.1 bar-5.0 bar.

7. The preparation method according to claim 1, characterized in that: The self-assembled active composite powder is freeze-dried, the freeze-drying temperature is controlled to be -80°C to -10°C, the drying time is 2h-10h, and then the temperature is increased to room temperature at a heating rate of 1°C / h-50°C / h.

8. The preparation method according to claim 1, characterized in that: Also includes: The powder after surface treatment is vacuum dried, and the vacuum drying temperature is controlled to be 50°C-200°C and the pressure is controlled to be 0.1bar-5bar.

9. A tantalum alloy metal powder suitable for metal additive manufacturing, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 8.

10. Use of the tantalum alloy metal powder according to claim 9 in additive manufacturing; The process of preparing tantalum alloy using the tantalum alloy metal powder comprises: According to the set three-dimensional model, the additive manufacturing processing path is set, and the laser additive manufacturing process is used to process and form the target solid part.

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