High-quality particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing and preparation method of high-quality particle-reinforced refractory high-entropy composite material spherical powder

Abstract

The invention discloses high-quality particle reinforced refractory high-entropy composite material spherical powder for additive manufacturing and a preparation method of the high-quality particle reinforced refractory high-entropy composite material spherical powder. The preparation method comprises the following steps: step 1, mechanically mixing various matrix powder raw materials with reinforcement powder; 2, pressing the mixed powder into raw material blocks; 3, the raw material block is subjected to vacuum non-consumable arc melting, and a particle-reinforced refractory high-entropy composite cast ingot is prepared; and 4, the cast ingot is subjected to ultrasonic atomization powder making, and particle-reinforced refractory high-entropy composite material powder is prepared. The particle-reinforced refractory high-entropy composite powder prepared through the method is extremely high in sphericity degree, good in fluidity, high in surface quality, free of segregation and uniform in structure and reinforcement, and can serve 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 high-quality 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 refer to composite materials prepared by introducing particle reinforcements into a matrix of four or more refractory metal elements (such as Nb, Ta, Mo, W, Zr, Re, Cr and Hf, etc.) in equal or nearly equal atomic ratios. This type of material has excellent high-temperature properties such as good high-temperature strength, phase structure stability, high melting point and high-temperature softening resistance. It is widely used in aerospace, energy storage, electronic devices and other fields, and shows great development potential.

[0003] Traditional refractory high-entropy composite materials are usually prepared by melting and casting methods, including vacuum arc melting, induction melting and electron beam melting, which are mainly used to produce refractory high-entropy composite materials with rod-shaped and ribbon-shaped structures. However, due to the high melting points and large differences of the constituent elements of refractory high-entropy composite materials, some high-melting-point elements are difficult to melt or the diffusion rate of molten atoms is slow, which leads to obvious element segregation and defects such as dendrite structure, pores and residual stress on the scale of hundreds of microns. At the same time, larger grains are not conducive to the strengthening effect of grain boundaries. 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 making is difficult, which ultimately leads to extremely low powder making 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 bonding 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-mentioned object, the present invention provides a method for preparing a spherical powder of a high-quality particle-reinforced refractory high-entropy composite material for additive manufacturing, which specifically comprises the following steps: 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: The ingot is subjected to ultrasonic atomization powdering to prepare a particle-reinforced refractory high-entropy composite material powder.

[0008] Preferably, in step one, the several kinds of 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, ZrB2.

[0009] 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.

[0010] Preferably, in step 2, the mixed powder raw materials are pressed into blocks by a molding press.

[0011] Preferably, in step 3, the vacuum non-consumable arc melting process specifically comprises 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 is 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 ingot is prepared.

[0012] Preferably, in step 4, the heat source input during 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.

[0013] Preferably, in step 4, the ultrasonic atomization powder making process is carried out in an inert gas.

[0014] Preferably, the ultrasonic atomization process is carried out in a vacuum chamber, and the vacuum degree of the vacuum chamber is less than 10 -2 Pa.

[0015] Another aspect of 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.

[0016] Preferably, the reinforcement powder is one of Al2O3, Y2O3, TiO2, ZrO2, and ZrB2; 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.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: 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.

[0018] 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 Figure 1 is a process flow chart of the present invention; Figure 2The SEM morphology images of the powder of Example 1 in different particle size ranges after sieving, wherein (a) is in the particle size range of 15-53 μm, (b) is in the particle size range of 53-100 μm, and (c) is in the particle size range of 100-150 μm; Figure 3 is the powder particle size distribution diagram of Example 1; Figure 4 Example 1: SEM micrograph of the cross section of powder particles with a particle size of 15-53 μm. DETAILED DESCRIPTION The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] 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 comprises the following steps: 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: subject the ingot to ultrasonic atomization powder making to prepare particle-reinforced refractory high-entropy composite material powder.

[0022] Embodiment 1: (1) Raw material preparation: Pure metal powders (purity > 99.9wt%) 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 > 99.99wt%, average particle size of 20nm) were used as particle reinforcement raw materials. The mass fractions of matrix raw materials and reinforcement raw materials were 99.5% and 0.5%, respectively.

[0023] (2) Mechanical mixing: The matrix raw material and the reinforcement raw material are mechanically mixed using a three-dimensional mixer. The main shaft speed of the mixer is 100 r / min and the mixing time is 2 hours. The three-dimensional movement of the raw materials through the mixing barrel eliminates the gravity segregation or powder agglomeration caused by centrifugal action between the powders, ensuring the uniformity of the powder mixing.

[0024] (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.

[0025] (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 use argon gas to purge the furnace four times. 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 evacuated 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 that can form pores or inclusions in the material, 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.

[0026] (5) Ultrasonic atomization powder making: First, place the smelted alloy ingot on the ultrasonic atomization table, input the heat source as 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 powder yield 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 the collision and agglomeration between droplets to a great extent and improving the powder quality.

[0027] 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), which 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.

[0028] 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.

[0029] Particle size (μm) Mass ratio (%) Average sphericity 15~53 50.07 0.931 53~100 15.31 0.916 100~150 4.19 0.912 >150 4.05 Large particles + residue 26.38

[0030] like Figure 2 As shown, it can be seen that the powders in three different particle size ranges have extremely high sphericity, high surface quality, and no satellite balls or sticky particles.

[0031] like Figure 3 As shown, it can be seen that the particle size is mainly distributed between 20 and 50 μm.

[0032] 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.

[0033] Embodiment 2: (1) Raw material preparation: Pure metal powders (purity > 99.9wt%) 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 > 99.9wt%, average particle size of 2μm) were used as the particle reinforcement raw materials. The mass fractions of the matrix raw materials and the reinforcement raw materials were 99% and 1%, respectively.

[0034] (2) Mechanical mixing: The matrix raw material and the reinforcement raw material are mechanically mixed using a three-dimensional mixer. The main shaft speed of the mixer is 100 r / min and the mixing time is 2 hours. The three-dimensional movement of the raw materials through the mixing barrel eliminates the gravity segregation or powder agglomeration caused by centrifugal action between the powders, ensuring the uniformity of the powder mixing.

[0035] (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.

[0036] (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 use argon gas to purge the furnace four times. 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 evacuated to a vacuum degree of 1×10 -4 ~1×10 -5Pa, 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 that can form pores or inclusions in the material, 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.

[0037] (5) Ultrasonic atomization powder making: First, place the smelted alloy ingot on the ultrasonic atomization table, input the heat source as 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 powder yield 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 the collision and agglomeration between droplets to a great extent and improving the powder quality.

[0038] 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), which 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.

[0039] 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.

[0040] Particle size (μm) Mass ratio (%) Average sphericity 15~53 54.25 0.925 53~100 13.42 0.912 100~150 3.51 0.907 >150 4.68 Large particles + residue 24.14

[0041] Embodiment 3: (1) Raw material preparation: Pure metal powders (purity > 99.9wt%) 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 > 99.9wt%, average particle size of 1μm) were used as the particle reinforcement raw materials. The mass fractions of the matrix raw materials and the reinforcement raw materials were 98.5% and 1.5%, respectively.

[0042] (2) Mechanical mixing: The matrix raw material and the reinforcement raw material are mechanically mixed using a three-dimensional mixer. The main shaft speed of the mixer is 100 r / min and the mixing time is 2 hours. The three-dimensional movement of the raw materials through the mixing barrel eliminates the gravity segregation or powder agglomeration caused by centrifugal action between the powders, ensuring the uniformity of the powder mixing.

[0043] (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.

[0044] (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 use argon gas to purge the furnace four times. 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 evacuated 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 that can form pores or inclusions in the material, 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.

[0045] (5) Ultrasonic atomization powder making: First, place the smelted alloy ingot on the ultrasonic atomization table, input the heat source as 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 powder yield 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 the collision and agglomeration between droplets to a great extent and improving the powder quality.

[0046] 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), which 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.

[0047] 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.

[0048] Particle size (μm) Mass ratio (%) Average sphericity 15~53 52.65 0.919 53~100 14.58 0.902 100~150 5.42 0.893 >150 3.47 Large particles + residue 23.88

[0049] Embodiment 4: (1) Raw material preparation: Pure metal powders (purity > 99.9wt%) 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 > 99.99wt%, average particle size 30nm) were used as the particle reinforcement raw materials. The mass fractions of the matrix raw materials and the reinforcement raw materials were 97% and 3%, respectively.

[0050] (2) Mechanical mixing: The matrix raw material and the reinforcement raw material are mechanically mixed using a three-dimensional mixer. The main shaft speed of the mixer is 100 r / min and the mixing time is 2 hours. The three-dimensional movement of the raw materials through the mixing barrel eliminates the gravity segregation or powder agglomeration caused by centrifugal action between the powders, ensuring the uniformity of the powder mixing.

[0051] (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.

[0052] (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 use argon gas to purge the furnace four times. 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 evacuated to a vacuum degree of 1×10 -4 ~1×10 -5Pa, 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.

[0053] (5) Ultrasonic atomization powder making: First, place the smelted alloy ingot on the ultrasonic atomization table, input the heat source as 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 powder yield 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 the collision and agglomeration between droplets to a great extent and improving the powder quality.

[0054] 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), which 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.

[0055] 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.

[0056] Particle size (μm) Mass ratio (%) Average sphericity 15~53 48.72 0.893 53~100 16.41 0.864 100~150 7.49 0.852 >150 3.97 Large particles + residue 23.41

[0057] Embodiment 5: (1) Raw material preparation: Pure metal powders (purity > 99.9wt%) 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 > 99.99wt%, average particle size 1μm) were used as the particle reinforcement raw materials. The mass fractions of the matrix raw materials and the reinforcement raw materials were 97% and 3%, respectively.

[0058] (2) Mechanical mixing: The matrix raw material and the reinforcement raw material are mechanically mixed using a three-dimensional mixer. The main shaft speed of the mixer is 100 r / min and the mixing time is 2 hours. The three-dimensional movement of the raw materials through the mixing barrel eliminates the gravity segregation or powder agglomeration caused by centrifugal action between the powders, ensuring the uniformity of the powder mixing.

[0059] (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.

[0060] (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 use argon gas to purge the furnace four times. 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 evacuated 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.

[0061] (5) Ultrasonic atomization powder making: First, place the smelted alloy ingot on the ultrasonic atomization table, input the heat source as 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 powder yield 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 the collision and agglomeration between droplets to a great extent and improving the powder quality.

[0062] 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), which 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.

[0063] 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.

[0064] Particle size (μm) Mass ratio (%) Average sphericity 15~53 52.12 0.904 53~100 13.49 0.891 100~150 6.13 0.859 >150 2.92 Large particles + residue 25.34

[0065] 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 principle 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 high-quality 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: The ingot is subjected to ultrasonic atomization powdering to prepare a particle-reinforced refractory high-entropy composite material powder.

2. The method for preparing a high-quality particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: 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.

3. The method for preparing a high-quality 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.

4. The method for preparing a high-quality 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 molding press.

5. The method for preparing a high-quality particle-reinforced refractory high-entropy composite 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 is 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 ingot is prepared.

6. The method for preparing a high-quality particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 1, characterized in that: 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.

7. The method for preparing a high-quality particle-reinforced refractory high-entropy composite material spherical powder for additive manufacturing according to claim 6, characterized in that: In step 4, the ultrasonic atomization powder making process is carried out in an inert gas.

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

9. A high-quality particle-reinforced refractory high-entropy composite spherical powder for additive manufacturing, characterized in that: The method is prepared by the method described in any one of claims 1 to 8.

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