A particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing and a preparation method thereof

Abstract

The present invention discloses a high-quality particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing and a preparation method thereof. The preparation method comprises the following steps: step 1, mechanically mixing a plurality of matrix powder raw materials with reinforcement powder; step 2, pressing the mixed powder into a raw material block; step 3, subjecting the raw material block to vacuum non-consumable arc melting to prepare a particle-reinforced refractory high-entropy composite material ingot; step 4, subjecting the ingot to ultrasonic atomization pulverization to prepare a particle-reinforced refractory high-entropy composite material powder. The particle-reinforced refractory high-entropy composite powder prepared by the method of the present invention has extremely high sphericity, good fluidity, high surface quality, no segregation phenomenon, and uniform structure and reinforcement, and can be used as a high-quality powder raw material for additive manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal powder preparation, and in particular relates to a particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing and a preparation method thereof. Background Art

[0002] Particle-reinforced refractory high-entropy composites (PRCs) are composites prepared by introducing particle reinforcement into a matrix of four or more refractory metal elements (such as Nb, Ta, Mo, W, Zr, Re, Cr, and Hf) in equal or near-equal atomic ratios. These materials exhibit excellent high-temperature properties, including high-temperature strength, phase structure stability, high melting points, and resistance to softening. They are widely used in aerospace, energy storage, electronics, and other fields, and demonstrate significant development potential.

[0003] Traditionally, refractory high-entropy composites are typically prepared using melting and casting methods, including vacuum arc melting, induction melting, and electron beam melting, which are primarily used to produce rod- and ribbon-shaped refractory high-entropy composites. However, due to the high and widely varying melting points of the constituent elements of refractory high-entropy composites, some high-melting-point elements are difficult to melt or the diffusion rate of molten atoms is slow, leading to significant element segregation and defects such as dendrites, pores, and residual stresses on a scale of hundreds of microns. Furthermore, larger grains are not conducive to grain boundary strengthening. In addition, most refractory high-entropy composites exhibit high brittleness and hardness at room temperature and are difficult to process into the desired shape. Compared with the traditional melting and casting method for preparing refractory high-entropy composites, additive manufacturing technology shows great application potential in the preparation of refractory high-entropy composites. Additive manufacturing is a new type of intelligent manufacturing technology that constructs complex three-dimensional shapes by accumulating materials layer by layer. Its advantages lie in unique flexibility, reduced defects, high precision, high efficiency and easy production of complex-shaped parts. The rapid solidification of the molten pool in the additive manufacturing process helps to reduce element segregation, inhibit the formation of brittle intermetallic compounds and unique microstructure, thereby significantly improving the mechanical properties of the components.

[0004] The raw materials used in additive manufacturing are mainly in the form of powder. Since refractory high-entropy alloys contain a variety of high-melting-point elements (such as tungsten, molybdenum, etc.), extremely high melting temperatures are required, and incomplete melting will cause the melt fluidity to deteriorate. Conventional atomization methods (such as gas atomization or water atomization) are difficult to meet the atomization conditions, and powder production is difficult, which ultimately leads to extremely low powder production efficiency, irregular powder shape, uneven internal elements, wide particle size distribution, poor powder fluidity and low surface quality. Especially after the introduction of particulate reinforcements, due to the significant difference in melting points between the reinforcement and matrix elements, interfacial adhesion and wettability between the reinforcement surface and the matrix are more prominent.

[0005] Based on the above reasons, optimizing the preparation process, improving the atomization technology, controlling the alloy composition and reinforcement distribution, etc., in order to improve the quality and performance of the powder, including high sphericity, no satellite balls, uniform element distribution, narrow particle size distribution, good fluidity and high surface quality, is of great significance for realizing the additive manufacturing of high-performance refractory high-entropy alloy composites. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-quality particle-reinforced refractory high-entropy composite material powder for additive manufacturing and a preparation method thereof, which solves the problem in the prior art that the quality and performance of particle-reinforced refractory high-entropy composite material powders are difficult to meet the processing requirements of additive manufacturing.

[0007] To achieve the above objectives, the present invention provides a method for preparing high-quality particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, which specifically comprises the following steps:

[0008] Step 1: Mechanically mix several matrix powder raw materials with reinforcement powder;

[0009] Step 2: Press the mixed powder into raw material blocks;

[0010] Step 3: subjecting the raw material block to vacuum non-consumable arc melting to prepare a particle-reinforced refractory high-entropy composite ingot;

[0011] Step 4: The ingot is subjected to ultrasonic atomization pulverization to prepare particle-reinforced refractory high-entropy composite material powder.

[0012] Preferably, in step one, the several matrix powder raw materials are Ti powder, Zr powder, Ta powder, Nb powder and Mo powder in a molar ratio of 1:1:0.7:1:1; the reinforcement powder is one of Al2O3, Y2O3, TiO2, ZrO2, and ZrB2.

[0013] Preferably, in step 1, a three-dimensional mixer is used to mechanically mix the matrix raw material and the reinforcement raw material, the main shaft speed of the mixer is 100 r / min, and the mixing time is 2 h.

[0014] Preferably, in step 2, the mixed powder raw materials are pressed into blocks by a forming press.

[0015] Preferably, in step 3, the vacuum non-consumable arc melting process specifically includes the following steps:

[0016] (1) Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas;

[0017] (2) Before smelting, the furnace was vacuumed to a vacuum degree of 1×10-4 ~1×10 -5 Pa;

[0018] (3) During the smelting process, the maximum smelting current is 1 kA, and the alloy ingot is remelted no less than 6 times, and finally a particle-reinforced refractory high-entropy composite material ingot is prepared.

[0019] Preferably, in step 4, the input heat source in the ultrasonic atomization powder making process is plasma, the current is 270-280A, the ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min.

[0020] Preferably, in step 4, the ultrasonic atomization powder making process is carried out in an inert gas.

[0021] Preferably, the ultrasonic atomization process is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa.

[0022] On the other hand, the present invention provides a high-quality particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, which is prepared by the above method.

[0023] Preferably, the reinforcement powder is one of Al2O3, Y2O3, TiO2, ZrO2, and ZrB2;

[0024] Among them, the preferred mass fraction of Al2O3 particles is 0.5%, and the average particle size is 20nm; the preferred mass fraction of Y2O3 particles is 1%, and the average particle size is 2μm; the preferred mass fraction of TiO2 particles is 1.5%, and the average particle size is 1μm; the preferred mass fraction of ZrO2 particles is 3%, and the average particle size is 30nm; the preferred mass fraction of ZrB2 particles is 3%, and the average particle size is 1μm.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] 1. The preparation method of the present invention optimizes the mechanical mixing process of various metal matrix powders and reinforcement raw materials, improves and adjusts the vacuum non-consumable arc melting process, optimizes and adjusts the atomization process parameters, ensures the uniformity of the distribution of internal elements and reinforcement particles in the particle-reinforced refractory high-entropy composite material powder, and at the same time achieves high-quality powder characteristics such as moderate powder particle size range, high sphericity, and no satellite balls, thereby effectively improving the purity and overall quality of the powder raw materials for additive manufacturing.

[0027] 2. The refractory high-entropy composite material powder prepared by the present invention contains different particle size distribution ranges. After screening at different particle sizes, it can be used as high-quality powder raw materials for additive manufacturing processes such as laser selective melting and directed energy deposition, and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a process flow chart of the present invention;

[0029] Figure 2 The SEM morphology images of the powder of Example 1 after sieving in different particle size ranges, wherein (a) is a particle size range of 15 to 53 μm, (b) is a particle size range of 53 to 100 μm, and (c) is a particle size range of 100 to 150 μm;

[0030] Figure 3 This is the powder particle size distribution diagram of Example 1;

[0031] Figure 4 Example 1: SEM micrograph of the cross section of powder particles with a particle size of 15 to 53 μm. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention and not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] like Figure 1 As shown, the present invention provides a method for preparing high-quality particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, characterized in that it includes the following steps:

[0034] Step 1: Mechanically mix several matrix powder raw materials with reinforcement powder;

[0035] Step 2: Press the mixed powder into raw material blocks;

[0036] Step 3: subjecting the raw material block to vacuum non-consumable arc melting to prepare a particle-reinforced refractory high-entropy composite ingot;

[0037] Step 4: The ingot is subjected to ultrasonic atomization pulverization to prepare particle-reinforced refractory high-entropy composite material powder.

[0038] Embodiment 1:

[0039] (1) Raw material preparation: Pure metal powders (purity > 99.9 wt%) Ti powder, Zr powder, Ta powder, Nb powder and Mo powder (molar ratio of 1:1:0.7:1:1) were used as the matrix raw materials of refractory high entropy composite materials, and Al2O3 particles (purity > 99.99 wt%, average particle size of 20 nm) were used as the particle reinforcement raw materials, where the mass fractions of the matrix raw material and the reinforcement raw material were 99.5% and 0.5%, respectively.

[0040] (2) Mechanical mixing: The matrix and reinforcement materials are mechanically mixed using a three-dimensional mixer with a main shaft speed of 100 r / min and a mixing time of 2 h. The three-dimensional movement of the raw materials through the mixing drum eliminates gravity segregation or powder agglomeration caused by centrifugal action, ensuring uniform powder mixing.

[0041] (3) Pressing the raw materials into blocks: The mixed powder raw materials are pressed into blocks by a forming press. This step helps to evenly distribute heat during subsequent smelting and prevents the powder from flying during the smelting process, resulting in adverse effects such as raw material loss.

[0042] (4) Vacuum non-consumable arc furnace smelting: Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas. The purpose of the purge is to ensure a high-purity environment during the smelting process and remove impurity gases such as oxygen and nitrogen in the furnace, thereby improving the purity of the smelted alloy and obtaining high-quality alloy ingots. Before smelting, the furnace needs to be vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa, the purpose of vacuuming is to remove the gas content in the furnace, reduce the occurrence of adverse reactions, and ensure that there is no residual gas in the material that can form pores or inclusions, thereby improving the quality of the alloy ingot. During the smelting process, in order to ensure that the refractory metal powder can be completely melted, the maximum smelting current is 1kA. In order to ensure that the elements in the alloy ingot after smelting are evenly distributed and there is no component segregation, the alloy ingot is remelted ≥ 6 times (including two smeltings after the alloy ingot is turned over), and finally an Al2O3 reinforced refractory high entropy composite material ingot is prepared.

[0043] (5) Ultrasonic atomization powder making: First, the smelted alloy ingot is placed on the ultrasonic atomization table, the input heat source is plasma, and the current is 270~280A. If the current is lower than this, it will affect the fluidity and surface tension of the alloy melt, making it difficult to form a uniform and continuous jet flow during the vibration atomization process, reducing the powder making efficiency, and affecting the particle size distribution, uniformity and sphericity of the powder. The ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min. The reason for selecting this vibration frequency and gas flow rate is to obtain the highest yield of powder in the target particle size range (15~53μm), and to reduce the speed at which the droplets detach from the melt film under vibration, thereby avoiding collision and agglomeration between droplets to a great extent and improving the powder quality.

[0044] Ultrasonic atomization is carried out in a vacuum chamber with a vacuum degree of less than 10 -2Pa. A vacuum degree lower than this will cause the powder to be contaminated, and the entire ultrasonic atomization process for preparing powder is carried out in an inert gas (such as argon). This can effectively reduce the occurrence of oxidation and other chemical reactions, thereby improving the stability of the ultrasonic atomization process and ensuring the purity and quality of the final powder.

[0045] The particle size distribution range, corresponding mass ratio and average sphericity of the particle-reinforced refractory high-entropy composite material powder finally prepared are shown in the following table.

[0046]

[0047] like Figure 2 As shown, the powders in three different particle size ranges have extremely high sphericity, high surface quality, and no satellite spheres or sticky particles.

[0048] like Figure 3 As shown, the particle size is mainly distributed between 20 and 50 μm.

[0049] like Figure 4 As shown, by observing the SEM structure of the powder particle cross section, it can be seen that the reinforcement is evenly distributed.

[0050] Example 2:

[0051] (1) Raw material preparation: Pure metal powders (purity > 99.9 wt%) Ti powder, Zr powder, Ta powder, Nb powder and Mo powder (molar ratio of 1:1:0.7:1:1) were used as the matrix raw materials of refractory high entropy composite materials, and Y2O3 particles (purity > 99.9 wt%, average particle size of 2 μm) were used as the particle reinforcement raw materials, where the mass fractions of the matrix raw material and the reinforcement raw material were 99% and 1%, respectively.

[0052] (2) Mechanical mixing: The matrix and reinforcement materials are mechanically mixed using a three-dimensional mixer with a main shaft speed of 100 r / min and a mixing time of 2 h. The three-dimensional movement of the raw materials through the mixing drum eliminates gravity segregation or powder agglomeration caused by centrifugal action, ensuring uniform powder mixing.

[0053] (3) Pressing the raw materials into blocks: The mixed powder raw materials are pressed into blocks by a forming press. This step helps to evenly distribute heat during subsequent smelting and prevents the powder from flying during the smelting process, resulting in adverse effects such as raw material loss.

[0054] (4) Vacuum non-consumable arc furnace smelting: Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas. The purpose of the purge is to ensure a high-purity environment during the smelting process and remove impurity gases such as oxygen and nitrogen in the furnace, thereby improving the purity of the smelted alloy and obtaining high-quality alloy ingots. Before smelting, the furnace needs to be vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa, the purpose of vacuuming is to remove the gas content in the furnace, reduce the occurrence of adverse reactions, and ensure that there is no residual gas in the material that can form pores or inclusions, thereby improving the quality of the alloy ingot. During the smelting process, in order to ensure that the refractory metal powder can be completely melted, the maximum smelting current is 1kA. In order to ensure that the elements in the alloy ingot after smelting are evenly distributed and there is no component segregation, the alloy ingot is remelted ≥ 6 times (including two smeltings after the alloy ingot is turned over), and finally a Y2O3 reinforced refractory high entropy composite material ingot is prepared.

[0055] (5) Ultrasonic atomization powder making: First, the smelted alloy ingot is placed on the ultrasonic atomization table, the input heat source is plasma, and the current is 270~280A. If the current is lower than this, it will affect the fluidity and surface tension of the alloy melt, making it difficult to form a uniform and continuous jet flow during the vibration atomization process, reducing the powder making efficiency, and affecting the particle size distribution, uniformity and sphericity of the powder. The ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min. The reason for selecting this vibration frequency and gas flow rate is to obtain the highest yield of powder in the target particle size range (15~53μm), and to reduce the speed at which the droplets detach from the melt film under vibration, thereby avoiding collision and agglomeration between droplets to a great extent and improving the powder quality.

[0056] Furthermore, ultrasonic atomization is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa. A vacuum degree lower than this will cause the powder to be contaminated, and the entire ultrasonic atomization process for preparing powder is carried out in an inert gas (such as argon). This can effectively reduce the occurrence of oxidation and other chemical reactions, thereby improving the stability of the ultrasonic atomization process and ensuring the purity and quality of the final powder.

[0057] The particle size distribution range, corresponding mass ratio and average sphericity of the particle-reinforced refractory high-entropy composite material powder finally prepared are shown in the following table.

[0058]

[0059] Example 3:

[0060] (1) Raw material preparation: Pure metal powders (purity > 99.9 wt%) Ti powder, Zr powder, Ta powder, Nb powder and Mo powder (molar ratio of 1:1:0.7:1:1) were used as the matrix raw materials of refractory high entropy composite materials, and TiO2 particles (purity > 99.9 wt%, average particle size of 1 μm) were used as the particle reinforcement raw materials, where the mass fractions of the matrix raw material and the reinforcement raw material were 98.5% and 1.5%, respectively.

[0061] (2) Mechanical mixing: The matrix and reinforcement materials are mechanically mixed using a three-dimensional mixer with a main shaft speed of 100 r / min and a mixing time of 2 h. The three-dimensional movement of the raw materials through the mixing drum eliminates gravity segregation or powder agglomeration caused by centrifugal action, ensuring uniform powder mixing.

[0062] (3) Pressing the raw materials into blocks: The mixed powder raw materials are pressed into blocks by a forming press. This step helps to evenly distribute heat during subsequent smelting and prevents the powder from flying during the smelting process, resulting in adverse effects such as raw material loss.

[0063] (4) Vacuum non-consumable arc furnace smelting: Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas. The purpose of the purge is to ensure a high-purity environment during the smelting process and remove impurity gases such as oxygen and nitrogen in the furnace, thereby improving the purity of the smelted alloy and obtaining high-quality alloy ingots. Before smelting, the furnace needs to be vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa, the purpose of vacuuming is to remove the gas content in the furnace, reduce the occurrence of adverse reactions, and ensure that there is no residual gas in the material that can form pores or inclusions, thereby improving the quality of the alloy ingot. During the smelting process, in order to ensure that the refractory metal powder can be completely melted, the maximum smelting current is 1kA. In order to ensure that the elements in the alloy ingot after smelting are evenly distributed and there is no component segregation, the alloy ingot is remelted ≥ 6 times (including two smeltings after the alloy ingot is turned over), and finally a TiO2 reinforced refractory high entropy composite material ingot is prepared.

[0064] (5) Ultrasonic atomization powder making: First, the smelted alloy ingot is placed on the ultrasonic atomization table, the input heat source is plasma, and the current is 270~280A. If the current is lower than this, it will affect the fluidity and surface tension of the alloy melt, making it difficult to form a uniform and continuous jet flow during the vibration atomization process, reducing the powder making efficiency, and affecting the particle size distribution, uniformity and sphericity of the powder. The ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min. The reason for selecting this vibration frequency and gas flow rate is to obtain the highest yield of powder in the target particle size range (15~53μm), and to reduce the speed at which the droplets detach from the melt film under vibration, thereby avoiding collision and agglomeration between droplets to a great extent and improving the powder quality.

[0065] Ultrasonic atomization is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa. A vacuum degree lower than this will cause the powder to be contaminated, and the entire ultrasonic atomization process for preparing powder is carried out in an inert gas (such as argon). This can effectively reduce the occurrence of oxidation and other chemical reactions, thereby improving the stability of the ultrasonic atomization process and ensuring the purity and quality of the final powder.

[0066] The particle size distribution range, corresponding mass ratio and average sphericity of the particle-reinforced refractory high-entropy composite material powder finally prepared are shown in the following table.

[0067]

[0068] Embodiment 4:

[0069] (1) Raw material preparation: Pure metal powders (purity > 99.9 wt%) Ti powder, Zr powder, Ta powder, Nb powder and Mo powder (molar ratio of 1:1:0.7:1:1) were used as the matrix raw materials of refractory high entropy composite materials, and ZrO2 particles (purity > 99.99 wt%, average particle size 30 nm) were used as the particle reinforcement raw materials, where the mass fractions of the matrix raw materials and the reinforcement raw materials were 97% and 3%, respectively.

[0070] (2) Mechanical mixing: The matrix and reinforcement materials are mechanically mixed using a three-dimensional mixer with a main shaft speed of 100 r / min and a mixing time of 2 h. The three-dimensional movement of the raw materials through the mixing drum eliminates gravity segregation or powder agglomeration caused by centrifugal action, ensuring uniform powder mixing.

[0071] (3) Pressing the raw materials into blocks: The mixed powder raw materials are pressed into blocks by a forming press. This step helps to evenly distribute heat during subsequent smelting and prevents the powder from flying during the smelting process, resulting in adverse effects such as raw material loss.

[0072] (4) Vacuum non-consumable arc furnace smelting: Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas. The purpose of the purge is to ensure a high-purity environment during the smelting process and remove impurity gases such as oxygen and nitrogen in the furnace, thereby improving the purity of the smelted alloy and obtaining high-quality alloy ingots. Before smelting, the furnace needs to be vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa, the purpose of vacuuming is to remove the gas content in the furnace, reduce the occurrence of adverse reactions, and ensure that there is no residual gas in the material that can form pores or inclusions, thereby improving the quality of the alloy ingot. During the smelting process, in order to ensure that the refractory metal powder can be completely melted, the maximum smelting current is 1kA. In order to ensure that the elements in the alloy ingot after smelting are evenly distributed and there is no component segregation, the alloy ingot is remelted ≥ 6 times (including two smeltings after the alloy ingot is turned over), and finally a ZrO2 reinforced refractory high entropy composite material ingot is prepared.

[0073] (5) Ultrasonic atomization powder making: First, the smelted alloy ingot is placed on the ultrasonic atomization table, the input heat source is plasma, and the current is 270~280A. If the current is lower than this, it will affect the fluidity and surface tension of the alloy melt, making it difficult to form a uniform and continuous jet flow during the vibration atomization process, reducing the powder making efficiency, and affecting the particle size distribution, uniformity and sphericity of the powder. The ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min. The reason for selecting this vibration frequency and gas flow rate is to obtain the highest yield of powder in the target particle size range (15~53μm), and to reduce the speed at which the droplets detach from the melt film under vibration, thereby avoiding collision and agglomeration between droplets to a great extent and improving the powder quality.

[0074] Ultrasonic atomization is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa. A vacuum degree lower than this will cause the powder to be contaminated, and the entire ultrasonic atomization process for preparing powder is carried out in an inert gas (such as argon). This can effectively reduce the occurrence of oxidation and other chemical reactions, thereby improving the stability of the ultrasonic atomization process and ensuring the purity and quality of the final powder.

[0075] The particle size distribution range, corresponding mass ratio and average sphericity of the particle-reinforced refractory high-entropy composite material powder finally prepared are shown in the following table.

[0076]

[0077] Example 5:

[0078] (1) Raw material preparation: Pure metal powders (purity > 99.9 wt%) Ti powder, Zr powder, Ta powder, Nb powder and Mo powder (molar ratio of 1:1:0.7:1:1) were used as the matrix raw materials of refractory high entropy composite materials, and ZrB2 particles (purity > 99.99 wt%, average particle size 1 μm) were used as the particle reinforcement raw materials, where the mass fractions of the matrix raw materials and the reinforcement raw materials were 97% and 3%, respectively.

[0079] (2) Mechanical mixing: The matrix and reinforcement materials are mechanically mixed using a three-dimensional mixer with a main shaft speed of 100 r / min and a mixing time of 2 h. The three-dimensional movement of the raw materials through the mixing drum eliminates gravity segregation or powder agglomeration caused by centrifugal action, ensuring uniform powder mixing.

[0080] (3) Pressing the raw materials into blocks: The mixed powder raw materials are pressed into blocks by a forming press. This step helps to evenly distribute heat during subsequent smelting and prevents the powder from flying during the smelting process, resulting in adverse effects such as raw material loss.

[0081] (4) Vacuum non-consumable arc furnace smelting: Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace four times with argon gas. The purpose of the purge is to ensure a high-purity environment during the smelting process and remove impurity gases such as oxygen and nitrogen in the furnace, thereby improving the purity of the smelted alloy and obtaining high-quality alloy ingots. Before smelting, the furnace needs to be vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa, the purpose of vacuuming is to remove the gas content in the furnace, reduce the occurrence of adverse reactions, and ensure that there is no residual gas in the material that can form pores or inclusions, thereby improving the quality of the alloy ingot. During the smelting process, in order to ensure that the refractory metal powder can be completely melted, the maximum smelting current is 1kA. In order to ensure that the elements in the alloy ingot after smelting are evenly distributed and there is no component segregation, the alloy ingot is remelted ≥ 6 times (including two smeltings after the alloy ingot is turned over), and finally a ZrB2 reinforced refractory high entropy composite material ingot is prepared.

[0082] (5) Ultrasonic atomization powder making: First, the smelted alloy ingot is placed on the ultrasonic atomization table, the input heat source is plasma, and the current is 270~280A. If the current is lower than this, it will affect the fluidity and surface tension of the alloy melt, making it difficult to form a uniform and continuous jet flow during the vibration atomization process, reducing the powder making efficiency, and affecting the particle size distribution, uniformity and sphericity of the powder. The ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min. The reason for selecting this vibration frequency and gas flow rate is to obtain the highest yield of powder in the target particle size range (15~53μm), and to reduce the speed at which the droplets detach from the melt film under vibration, thereby avoiding collision and agglomeration between droplets to a great extent and improving the powder quality.

[0083] Ultrasonic atomization is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa. A vacuum degree lower than this will cause the powder to be contaminated, and the entire ultrasonic atomization process for preparing powder is carried out in an inert gas (such as argon). This can effectively reduce the occurrence of oxidation and other chemical reactions, thereby improving the stability of the ultrasonic atomization process and ensuring the purity and quality of the final powder.

[0084] The particle size distribution range, corresponding mass ratio and average sphericity of the particle-reinforced refractory high-entropy composite material powder finally prepared are shown in the following table.

[0085]

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technology in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, characterized in that: The following steps are involved: Step 1: Mechanically mix several matrix powder raw materials with reinforcement powder; Step 2: Press the mixed powder into raw material blocks; Step 3: subjecting the raw material block to vacuum non-consumable arc melting to prepare a particle-reinforced refractory high-entropy composite ingot; Step 4: subjecting the ingot to ultrasonic atomization pulverization to prepare particle-reinforced refractory high-entropy composite material powder; In step 1, the matrix powder raw materials are Ti powder, Zr powder, Ta powder, Nb powder and Mo powder in a molar ratio of 1:1:0.7:1:1; the reinforcement powder is one of Al2O3, Y2O3, TiO2, ZrO2 and ZrB2; In step 4, the input heat source in the ultrasonic atomization powder making process is plasma, the current is 270-280A, the ultrasonic vibration frequency used is 40kHz, the amplitude displacement is 100%, and the gas flow rate is 10NL / min.

2. The method for preparing a particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: In step 1, a three-dimensional mixer is used to mechanically mix the matrix raw material and the reinforcement raw material. The main shaft speed of the mixer is 100 r / min, and the mixing time is 2 h.

3. The method for preparing a particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: In step 2, the mixed powder raw materials are pressed into blocks by a forming press.

4. The method for preparing a particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: In step 3, the vacuum non-consumable arc melting process specifically includes the following steps: (1) Place the raw material block in a water-cooled copper crucible in a vacuum non-consumable melting furnace, close the furnace door, and purge the furnace with argon gas four times; (2) Before smelting, the furnace was vacuumed to a vacuum degree of 1×10 -4 ~1×10 -5 Pa; (3) During the smelting process, the maximum smelting current is 1 kA, and the alloy ingot is remelted no less than 6 times, and finally a particle-reinforced refractory high-entropy composite material ingot is prepared.

5. The method for preparing a particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: In step 4, the ultrasonic atomization powder making process is carried out in an inert gas.

6. The method for preparing a particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: The ultrasonic atomization process is carried out in a vacuum chamber with a vacuum degree of less than 10 -2 Pa.

7. A particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, characterized in that: The method is prepared by the method according to any one of claims 1 to 6.

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