Preparation method of high-purity refractory high-entropy alloy spherical powder

Abstract

The present invention provides a method for preparing high-purity refractory high-entropy alloy spherical powder, and relates to the technical field of powder material preparation. The present invention adopts a water-cooled copper crucible to melt the alloy, which solves the problem of the reaction between Hf, Ti, Nb, Zr, Ta, V, and Mo active elements in the alloy and ceramics in the traditional vacuum gas atomization process, effectively avoids impurities from entering the alloy, and improves the purity of the alloy powder. In addition, the water-cooled copper crucible can fully melt alloys with a melting point higher than 1700°C, which is impossible for ordinary ceramic crucibles. Compared with the existing electrode induction gas atomization process, this method has no special requirements for the shape of the raw materials, has low gas consumption, high atomization efficiency, and saves costs.

Description

Technical Field

[0001] The invention relates to the technical field of powder material preparation, and in particular to a method for preparing high-purity refractory high-entropy alloy spherical powder. Background Art

[0002] High entropy alloys are generally simple phase solid solution alloys composed of five or more metal elements with equal atomic ratios. Due to their thermodynamic high entropy effect, structural lattice distortion effect, dynamic hysteresis diffusion effect and "cocktail" effect in performance, high entropy alloys have the characteristics of high strength, high hardness, high wear resistance or high temperature softening resistance. They have broad application space in wear-resistant coatings, nuclear structural materials, optical transmission materials, biomedical materials, hydrogen storage materials, ship and marine engineering materials, thermoelectric materials, superconducting materials and electromagnetic materials.

[0003] Refractory high entropy alloys are a type of high entropy alloy. They generally contain high melting point metal elements such as Ti, Zr, Hf, Nb, Ta, Mo, and W. Their crystal structure is a single-phase BCC structure. The alloy has excellent mechanical properties and excellent radiation resistance. Therefore, it has broad application prospects in nuclear radiation-resistant components. At present, it is an ideal way to form refractory high entropy alloy components through additive manufacturing, so it is necessary to prepare refractory high entropy alloy powder. The traditional method uses a vacuum gas atomization process. Since the alloy has a high melting point, which exceeds the traditional gas atomization alloy melting temperature, and contains many active elements and high alloy activity, it will react with ceramics. If the electrode induction gas atomization process is used, due to the high viscosity of the alloy, it is difficult to prepare regular rods, powder making is difficult, and the cost is high. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing high-purity refractory high-entropy alloy spherical powder to solve the above problems.

[0005] Based on the above purpose, the present invention provides a method for preparing high-purity refractory high-entropy alloy spherical powder, which is carried out according to the following steps:

[0006] S1. Determine the alloy composition and ratio, add the metal block into the suspension smelting water-cooled copper crucible according to the alloy composition and ratio, and melt and condense the metal block into an alloy ingot.

[0007] S2. Place the alloy ingot into the water-cooled copper crucible of the suspension smelting atomization powder making equipment, and evacuate the suspension smelting atomization powder making equipment to 7×10 -2 Pa, fill the suspension smelting atomization powder making equipment with inert gas to make the gas pressure reach a slight positive pressure of 50~300kPa.

[0008] S3, turn on the first power supply, the power of the first power supply increases gradually to 200-350kW, and heats the alloy ingot; at the same time, turn on the second power supply to preheat the guide tube connected to the bottom of the water-cooled copper crucible, and the current of the second power supply is 5-10A.

[0009] S4. When the alloy ingot is completely melted and a hump appears in the water-cooled copper crucible, continue to heat the alloy liquid for 5 to 10 minutes, increase the second power supply current to 10 to 25 A, and continue heating for 60 to 100 seconds.

[0010] S5. When the alloy liquid temperature is 250-300°C higher than the alloy melting point and the temperature in the flow guide tube reaches the alloy melting point, adjust the second power supply current to 20-30A, turn on the atomizing gas at the same time, and set the atomizing gas pressure to 2-8Mpa.

[0011] S6. Insert the guide tube into the atomizer of the suspension smelting atomization powder making equipment, and impact the alloy liquid flowing out of the end of the guide tube into alloy droplets through the atomizing gas at the outlet of the atomizer, and the alloy droplets are condensed into powder particles.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a water-cooled copper crucible to melt the alloy, which solves the problem of the reaction between Hf, Ti, Nb, Zr, Ta, V, and Mo active elements in the alloy and ceramics in the traditional vacuum gas atomization process, effectively prevents impurities from entering the alloy, and improves the purity of the alloy powder. In addition, the water-cooled copper crucible can fully melt alloys with a melting point higher than 1700°C, which is impossible with ordinary ceramic crucibles. Compared with the existing electrode induction gas atomization process, this method has no special requirements for the shape of the raw materials, has low gas consumption, high atomization efficiency, and saves costs.

[0013] Furthermore, the alloy components in S1 include three or more elements of Ti, Zr, Cr, Hf, Nb, Ta, Mo, W, and V, wherein the content of each constituent element is greater than or equal to 5wt% and less than or equal to 50wt%.

[0014] Furthermore, the purity of the metal block in S1 is greater than 99%.

[0015] Furthermore, the atomizing gas is argon or helium, and the purity is greater than or equal to 99.99%.

[0016] Furthermore, the inner diameter of the flow guide tube is 4-8 mm.

[0017] Furthermore, the step of turning on the first power supply in S3 to perform gradient temperature increase heating on the alloy ingot is: setting the power of the first power supply to 10~100kW, heating the alloy ingot for 5~10 minutes; setting the power of the first power supply to 100~200kW, heating the alloy ingot for 5~10 minutes, setting the power of the first power supply to 200~350kW, and continuing to heat the alloy ingot.

[0018] Furthermore, after S6, the method further includes: the powder particles are collected in a powder collecting tank, and the powder particles are sieved to obtain alloy spherical powder of a desired particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a suspension melting atomization powder making device for a method for preparing a high-purity refractory high-entropy alloy spherical powder provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a water-cooled copper crucible for a method for preparing a high-purity refractory high-entropy alloy spherical powder provided in an embodiment of the present invention;

[0021] Figure 3 SEM image of HfNbZrTi alloy powder provided by the method for preparing high-purity refractory high-entropy alloy spherical powder in an embodiment of the present invention;

[0022] Figure 4 Laser particle size distribution diagram of HfNbZrTi alloy powder after screening in the method for preparing high-purity refractory high-entropy alloy spherical powder provided in an embodiment of the present invention;

[0023] Figure 5 SEM image of HfNbZrTiV alloy powder provided by the method for preparing high-purity refractory high-entropy alloy spherical powder in an embodiment of the present invention;

[0024] Figure 6 Laser particle size distribution diagram of HfNbZrTiV alloy powder after screening in the method for preparing high-purity refractory high-entropy alloy spherical powder provided in an embodiment of the present invention;

[0025] Figure 7 SEM image of HfNbZrTiVTaMo alloy powder provided by the method for preparing high-purity refractory high-entropy alloy spherical powder in an embodiment of the present invention;

[0026] Figure 8 Laser particle size distribution diagram of HfNbZrTiVTaMo alloy powder after screening in the method for preparing high-purity refractory high-entropy alloy spherical powder provided in an embodiment of the present invention.

[0027] The markings in the figure are: 1. water-cooled copper crucible; 2. first induction coil; 3. second induction coil; 4. alloy liquid; 5. flow guide tube; 6. atomization chamber; 7. powder particles; 8. fan. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0029] The present invention provides a method for preparing a high-purity refractory high-entropy alloy spherical powder, which is carried out according to the following steps:

[0030] S1. Determine the alloy composition and proportion. The alloy composition is selected from Ti, Zr, Cr, Hf, Nb, Ta, Mo, W, and V, including at least three of the above elements. The proportion of each element is set according to the alloy atomic ratio or mass ratio, and is set according to actual needs, but the content of each element must be greater than or equal to 5wt% and less than or equal to 50wt%.

[0031] The required metal block is determined according to the alloy composition and proportion, and the purity of the metal block is greater than 99%. The metal block is added to the suspension smelting water-cooled copper crucible in the suspension smelting chamber, and the suspension smelting chamber is evacuated to 5×10 -3 Pa, argon is introduced into the suspension smelting chamber. The smelting power supply is turned on, and the smelting power supply power is increased in a gradient manner until the smelting power supply power reaches 200-350 kW. The metal block is melted in the suspension smelting water-cooled copper crucible, and condensed after melting to obtain an alloy ingot to ensure the uniformity of the alloy elements.

[0032] S2, such as Figure 1 As shown, the suspension smelting atomization powder making equipment consists of a smelting chamber and an atomization chamber 6. A water-cooled copper crucible 1 is provided in the smelting chamber. The alloy ingot is taken out of the suspension smelting chamber and placed in the water-cooled copper crucible 1. The suspension smelting atomization powder making equipment is evacuated to 7×10 -2 Pa, close the vacuum pump and vacuum valve, fill the suspension smelting atomization powder making equipment with inert gas, and make the air pressure in the smelting chamber and atomization bin 6 reach a slight positive pressure of 50~300kPa.

[0033] S3, the first power supply is connected to the first induction coil 2, such as Figure 2 As shown, the first induction coil 2 is wound on the water-cooled copper crucible 1. The bottom of the water-cooled copper crucible 1 is connected to a flow guide tube 5, and the inner diameter of the flow guide tube 5 is 4-8 mm. The second induction coil 3 is wound on the flow guide tube 5, and the second induction coil 3 is connected to the second power supply.

[0034] The first power supply is turned on to heat the alloy ingot with a gradient temperature increase, and the specific steps are: setting the power of the first power supply to 10-100kW, heating the alloy ingot for 5-10 minutes; setting the power of the first power supply to 100-200kW, heating the alloy ingot for 5-10 minutes, setting the power of the first power supply to 200-350kW, and continuing to heat the alloy ingot. While the first power supply is turned on, the second power supply is turned on to preheat the guide tube 5 connected to the bottom of the water-cooled copper crucible 1, and the current of the second power supply is 5-10A.

[0035] S4. When the alloy ingot is completely melted and a hump appears in the water-cooled copper crucible 1, the first power source maintains the current power and continues to heat the alloy liquid 4 for 5 to 10 minutes. The current of the second power source is increased to 10 to 25 A and the heating is continued for 60 to 100 seconds.

[0036] S5. When the temperature of the alloy liquid 4 is higher than the alloy melting point by 250-300°C and the temperature in the flow guide tube 5 reaches the alloy melting point, turn on the fan 8, vacuum butterfly valve, and cyclone powder collecting butterfly valve of the suspension smelting atomization powder making equipment in sequence, turn on the atomizing gas, and set the pressure of the atomizing gas to 2-8Mpa. The atomizing gas uses argon or helium with a purity greater than or equal to 99.99%, and the content of other impurities in the gas is less than 10ppm. At the same time, adjust the current of the second power supply to 20-30A.

[0037] S6, entering the atomization stage, the alloy liquid 4 in the crucible flows into the guide tube 5, and the guide tube 5 is inserted into the atomizer in the atomization bin 6. The atomized gas at the outlet of the atomizer impacts and crushes the alloy liquid 4 flowing out of the end of the guide tube 5, and under the action of surface tension, 4 drops of alloy liquid are formed. During the flight of the alloy liquid 4 drops in the atomization bin 6, they condense into powder particles 7. A powder collection tube is set below the atomization bin 6, and the powder particles 7 enter the powder collection tank for collection.

[0038] After the atomization is completed, the atomizing gas, vacuum butterfly valve, cyclone powder collecting butterfly valve and fan 8 are closed in sequence, and the first power supply is turned off at the same time, and the current of the second power supply is gradually reduced until it stops. After the powder particles 7 are cooled, the powder particles 7 are sieved to obtain alloy spherical powders of the desired particle size.

[0039] The following is explained in conjunction with specific embodiments:

[0040] Embodiment 1:

[0041] The spherical powder of alloy HfNbZrTi is prepared according to the following steps:

[0042] 1. The ratio of elements in the alloy HfNbZrTi is calculated according to the following atomic ratio: Hf:Nb:Zr:Ti=1:1:1:1, and the purity of the metal block is ≥99%.

[0043] 2. Pre-alloying:

[0044] The first step is to put the metal blocks with the above proportions into a suspension smelting water-cooled copper crucible.

[0045] The second step is to evacuate the suspension melting chamber. When the vacuum reaches 5×10 -3 Next, argon is filled into the suspension smelting chamber as a protective gas.

[0046] The third step is to turn on the smelting power supply and increase the smelting power supply power to 200kW in a gradient manner. The specific process is: set the smelting power supply power to 50~70kW, stabilize for 3~5 minutes; then increase the smelting power supply power to 100kW, keep warm for 3~5 minutes; finally increase the smelting power supply power to 200kW, and melt the alloy for 10~15 minutes. After the metal block is melted, solidify and cool it to obtain an alloy ingot.

[0047] Step 4: Take out the alloy ingot and put it into the water-cooled copper crucible 1 of the suspension smelting atomization powder making equipment to enter the suspension atomization powder making process.

[0048] 3. Suspension smelting and atomization powder making:

[0049] The first step is to evacuate the suspension smelting atomization powder making equipment to 7×10 -2 Pa, close the vacuum pump and the vacuum valve, and inflate the vacuum melting chamber and the atomization chamber 6 to 100 kPa.

[0050] The second step is to turn on the first power supply to heat the HfNbZrTi alloy, and at the same time turn on the second power supply to preheat the guide connected to the bottom of the crucible, and the preheating current is 8A. The power gradient of the first power supply is increased, specifically: set the power of the first power supply to 30kW, and heat up for 10 minutes; set the power of the first power supply to 200kW, and heat up for 8 minutes; set the power of the first power supply to 250kW, and continue to melt the alloy. When the power of the first power supply reaches 300kW, the alloy is completely melted and then heated at the current power for 10 minutes. Use an infrared temperature measuring device to measure the temperature of the alloy liquid 4. When a hump appears on the alloy liquid 4 and the temperature reaches 250℃~300℃ above the melting point of the HfNbZrTi alloy, increase the current of the second power supply to 20A to preheat the guide.

[0051] Step 3: When the flow guide temperature reaches the melting point of the alloy, turn on the fan 8, vacuum butterfly valve, cyclone powder collecting butterfly valve, and atomizing gas in sequence, and set the atomizing gas pressure to 5MPa for atomization. After the HfNbZrTi alloy liquid 4 flows out from the bottom of the crucible, it enters the flow guide tube 5 connected to the crucible. The flow guide tube 5 is inserted into the atomizer. When the alloy liquid 4 reaches the outlet at the end of the flow guide tube 5, the high-pressure inert gas flow through the outlet of the atomizer impacts and breaks the molten metal, and spheroidizes to form small droplets under the action of surface tension. The metal droplets cool and solidify during the flight of the atomization chamber to form powder particles 7 that enter the powder collection tank below for collection.

[0052] Step 4: After atomization is completed, the air pressure, vacuum butterfly valve, cyclone powder collecting butterfly valve, and fan 8 are closed in sequence, and at the same time, the first power supply stops heating, and the second power supply gradually reduces the current until the heating stops.

[0053] 4. Powder screening process:

[0054] After the powder particles 7 are cooled, the powder particles 7 are collected and enter a subsequent screening process to obtain HfNbZrTi alloy powder of a desired particle size.

[0055] The morphology of HfNbZrTi powder prepared by this method is as follows Figure 3 As shown, it can be seen that the powder morphology is spherical, the oxygen content of powder particles 7 is 850ppm, and the gas consumption per kilogram of atomized powder is 7kg argon. In contrast, the oxygen content of powders produced by electrode induction atomization process on the market is generally above 1000ppm, and the gas consumption per kilogram of atomized powder is 60kg argon. After screening, the powder particle size distribution is as follows Figure 4 As shown in the figure, the D10 of the powder is 20.14μm, the D50 is 34.49μm, and the D90 is 54.12μm, which meets the powder particle size requirements for additive manufacturing processes. The powder with this particle size distribution exhibits excellent fluidity and loose tap density. After testing, the powder fluidity is 18.2s / 50g, and the powder loose density is 4.3g / cm 3 The tap density of the powder is 5.0 g / cm 3 .

[0056] Embodiment 2:

[0057] The spherical powder of alloy HfNbZrTiV is prepared according to the following steps:

[0058] 1. The ratio of elements in the alloy HfNbZrTiV is calculated according to the following atomic ratio: Hf:Nb:Zr:Ti:V=1:1:1:1:1, and the purity of the metal block is ≥99%.

[0059] 2. Pre-alloying:

[0060] The first step is to place the metal blocks with the above proportions into a suspension smelting water-cooled copper crucible.

[0061] The second step is to evacuate the suspension melting chamber. When the vacuum reaches 5×10 -3 Next, argon is filled into the suspension smelting chamber as a protective gas.

[0062] The third step is to turn on the smelting power supply and increase the smelting power supply power to 280kW in a gradient manner. The specific process is: set the smelting power supply power to 50-70kW and stabilize it for 5 minutes; then increase the smelting power supply power to 100kW and keep it warm for 5 minutes; finally increase the smelting power supply power to 280kW and melt the alloy for 5 minutes. After the metal block is melted, it is solidified and cooled to obtain an alloy ingot.

[0063] The fourth step is to take out the alloy ingot and put it into the water-cooled copper crucible 1 of the suspension smelting atomization powder making equipment to enter the suspension atomization powder making process.

[0064] 3. Suspension smelting and atomization powder making:

[0065] The first step is to evacuate the suspension smelting atomization powder making equipment to 7×10 -2 Pa, close the vacuum pump and the vacuum valve, and inflate the vacuum melting chamber and the atomization chamber 6 to 100 kPa.

[0066] The second step is to turn on the first power supply to heat the HfNbZrTiV alloy, and at the same time turn on the second power supply to preheat the guide connected to the bottom of the crucible, and the preheating current is 8A. The power gradient of the first power supply is increased, specifically: set the power of the first power supply to 50kW, and heat up for 10 minutes; set the power of the first power supply to 150kW, and heat up for 8 minutes; set the power of the first power supply to 200kW, and continue to melt the alloy. When the power of the first power supply reaches 250kW, the alloy is completely melted and the current power is continued to be heated for 10 minutes. Use an infrared temperature measuring device to measure the temperature of the alloy liquid 4. When a hump appears on the alloy liquid 4 and the temperature reaches 250℃~300℃ above the melting point of the HfNbZrTiV alloy, increase the current of the second power supply to 20A to preheat the guide.

[0067] Step 3: When the flow guide temperature reaches the melting point of the alloy, turn on the fan 8, vacuum butterfly valve, cyclone powder collecting butterfly valve, and atomizing gas in sequence, and set the atomizing gas pressure to 5MPa for atomization. After the HfNbZrTiV alloy liquid 4 flows out from the bottom of the crucible, it enters the flow guide tube 5 connected to the crucible. The flow guide tube 5 is inserted into the atomizer. When the alloy liquid 4 reaches the outlet at the end of the flow guide tube 5, the high-pressure inert gas flow through the outlet of the atomizer impacts and breaks the molten metal, and spheroidizes to form small droplets under the action of surface tension. The metal droplets cool and solidify during the flight of the atomization chamber to form powder particles 7 that enter the powder collection tank below for collection.

[0068] Step 4: After atomization is completed, the air pressure, vacuum butterfly valve, cyclone powder collecting butterfly valve, and fan 8 are closed in sequence, and at the same time, the first power supply stops heating, and the second power supply gradually reduces the current until the heating stops.

[0069] 4. Powder screening process:

[0070] After the powder particles 7 are cooled, the powder particles 7 are collected and enter a subsequent screening process to obtain HfNbZrTiV alloy powder of a desired particle size.

[0071] The morphology of HfNbZrTiV powder prepared by this method is as follows Figure 5As shown, it can be seen that the powder morphology is spherical, the oxygen content of the powder particles 7 is 900ppm, and the gas consumption per kilogram of atomized powder is 7.5kg argon. In contrast, the oxygen content of the powder produced by the electrode induction atomization process on the market is generally above 1000ppm, and the gas consumption per kilogram of atomized powder is 60kg argon. After screening, the powder particle size distribution is as follows Figure 6 As shown in the figure, the D10 of the powder is 20.65μm, the D50 is 35.04μm, and the D90 is 53.55μm, which meets the powder particle size requirements for additive manufacturing processes. The powder with this particle size distribution exhibits excellent fluidity and loose tap density. After testing, the powder fluidity is 17.5s / 50g, and the powder loose density is 4.4g / cm 3 The tap density of the powder is 5.0 g / cm 3 .

[0072] Embodiment 3:

[0073] The spherical powder of alloy HfNbZrTiTaMo is prepared according to the following steps:

[0074] 1. The ratio of elements in the alloy HfNbZrTiTaMo is calculated according to the following atomic ratio: Hf:Nb:Zr: Ti: Ta: Mo=1:1:1:1:1:1, and the purity of the metal block is ≥99%.

[0075] 2. Pre-alloying:

[0076] The first step is to put the metal blocks with the above proportions into a suspension smelting water-cooled copper crucible.

[0077] The second step is to evacuate the suspension melting chamber. When the vacuum reaches 5×10 -3 Next, argon is filled into the suspension smelting chamber as a protective gas.

[0078] The third step is to turn on the smelting power supply and increase the smelting power supply power to 350kW in a gradient manner. The specific process is: set the smelting power supply power to 50~70kW and stabilize it for 5 minutes; then increase the smelting power supply power to 150kW and keep it warm for 5 minutes; finally increase the smelting power supply power to 350kW and melt the alloy for 5 minutes. After the metal block is melted, it is solidified and cooled to obtain an alloy ingot.

[0079] Step 4: Take out the alloy ingot and put it into the water-cooled copper crucible 1 of the suspension smelting atomization powder making equipment to enter the suspension atomization powder making process.

[0080] 3. Suspension smelting and atomization powder making:

[0081] The first step is to evacuate the suspension smelting atomization powder making equipment to 7×10 -2Pa, close the vacuum pump and the vacuum valve, and inflate the vacuum melting chamber and the atomization chamber 6 to 100 kPa.

[0082] The second step is to turn on the first power supply to heat the HfNbZrTiVTaMo alloy, and at the same time turn on the second power supply to preheat the guide connected to the bottom of the crucible, and the preheating current is 8A. The power gradient of the first power supply is increased, specifically: set the power of the first power supply to 50kW, and heat up for 10 minutes; set the power of the first power supply to 150kW, and heat up for 8 minutes; set the power of the first power supply to 250kW, and continue to melt the alloy. When the power of the first power supply reaches 300kW, the alloy is completely melted and then heated at the current power for 10 minutes. Use an infrared temperature measuring device to measure the temperature of the alloy liquid 4. When a hump appears on the alloy liquid 4 and the temperature reaches 250℃~300℃ above the melting point of the HfNbZrTiVTaMo alloy, increase the current of the second power supply to 20A to preheat the guide.

[0083] Step 3: When the flow guide temperature reaches the melting point of the alloy, turn on the fan 8, vacuum butterfly valve, cyclone powder collecting butterfly valve, and atomizing gas in sequence, and set the atomizing gas pressure to 5MPa for atomization. After the HfNbZrTiVTaMo alloy liquid 4 flows out from the bottom of the crucible, it enters the flow guide tube 5 connected to the crucible. The flow guide tube 5 is inserted into the atomizer. When the alloy liquid 4 reaches the outlet at the end of the flow guide tube 5, the high-pressure inert gas flow through the outlet of the atomizer impacts and breaks the molten metal, and spheroidizes to form small droplets under the action of surface tension. The metal droplets cool and solidify during the flight of the atomization chamber to form powder particles 7 that enter the powder collection tank below for collection.

[0084] Step 4: After atomization is completed, the air pressure, vacuum butterfly valve, cyclone powder collecting butterfly valve, and fan 8 are closed in sequence, and at the same time, the first power supply stops heating, and the second power supply gradually reduces the current until the heating stops.

[0085] 4. Powder screening process:

[0086] After the powder particles 7 are cooled, the powder particles 7 are collected and enter a subsequent screening process to obtain HfNbZrTiVTaMo alloy powder of a desired particle size.

[0087] The morphology of HfNbZrTiVTaMo powder prepared by this method is as follows Figure 7 As shown, it can be seen that the powder morphology is spherical, the oxygen content of powder particles 7 is 870ppm, and the gas consumption per kilogram of atomized powder is 8kg argon. In contrast, the oxygen content of powders produced by electrode induction atomization process on the market is generally above 1000ppm, and the gas consumption per kilogram of atomized powder is 70kg argon. After screening, the powder particle size distribution is as follows Figure 8As shown in the figure, the D10 of the powder is 29.13μm, the D50 is 40.52μm, and the D90 is 56.70μm, which meets the powder particle size requirements for additive manufacturing processes. The powder with this particle size distribution exhibits excellent fluidity and loose tap density. After testing, the powder fluidity is 15.3s / 50g, and the powder loose density is 4.9g / cm 3 The tap density of the powder is 5.6 g / cm 3 .

[0088] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing high-purity refractory high-entropy alloy spherical powder, characterized in that: Follow these steps: S1. Determine the alloy composition and ratio, add the metal block into a suspension smelting water-cooled copper crucible according to the alloy composition and ratio, and melt and condense the metal block into an alloy ingot; S2. Place the alloy ingot into the water-cooled copper crucible of the suspension smelting atomization powder making equipment, and evacuate the suspension smelting atomization powder making equipment to 7×10 -2 Pa, fill the suspension smelting atomization powder making equipment with inert gas to make the gas pressure reach a slight positive pressure of 50~300kPa; The first power supply is connected to the first induction coil, the first induction coil is wound on a water-cooled copper crucible, a flow guide tube is connected to the bottom of the water-cooled copper crucible, a second induction coil is wound on the flow guide tube, and the second induction coil is connected to the second power supply; S3, turning on the first power supply, the power of the first power supply is gradually increased to 200-350kW, and the alloy ingot is heated; at the same time, the second power supply is turned on to preheat the guide tube connected to the bottom of the water-cooled copper crucible, and the current of the second power supply is 5-10A; S4. When the alloy ingot is completely melted and a hump appears in the water-cooled copper crucible, continue to heat the alloy liquid for 5 to 10 minutes, increase the second power supply current to 10 to 25 A, and continue heating for 60 to 100 seconds; S5. When the alloy liquid temperature is higher than the alloy melting point by 250-300°C and the temperature in the flow guide tube reaches the alloy melting point, adjust the second power supply current to 20-30A, turn on the atomizing gas, and set the atomizing gas pressure to 2-8MPa. S6, inserting the guide tube into the atomizer of the suspension smelting atomization powder making equipment, impacting the alloy liquid flowing out of the end of the guide tube into alloy droplets through the atomizing gas at the outlet of the atomizer, and condensing the alloy droplets into powder particles; The alloy components in S1 include three or more elements of Ti, Zr, Cr, Hf, Nb, Ta, Mo, W, and V, wherein the content of each component element is greater than or equal to 5wt% and less than or equal to 50wt%; The step of starting the first power supply to perform gradient heating on the alloy ingot in S3 is: The power of the first power supply is set to 10-100 kW, and the alloy ingot is heated for 5-10 minutes; Set the first power source to 100-200 kW and heat the alloy ingot for 5-10 minutes. Set the first power supply power to 200~350kW and continue to heat the alloy ingot.

2. The method for preparing high-purity refractory high-entropy alloy spherical powder according to claim 1, characterized in that: The purity of the metal block in S1 is greater than 99%.

3. The method for preparing high-purity refractory high-entropy alloy spherical powder according to claim 1, characterized in that: The atomizing gas is argon or helium with a purity greater than or equal to 99.99%.

4. The method for preparing high-purity refractory high-entropy alloy spherical powder according to claim 1, characterized in that: The inner diameter of the guide tube is 4~8mm.

5. The method for preparing high-purity refractory high-entropy alloy spherical powder according to claim 1, characterized in that: After S6, the process also includes: the powder particles enter a powder collecting tank for collection, and the powder particles are sieved to obtain alloy spherical powder of a desired particle size.

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