Multi-phase high-entropy alloy material with good high-temperature mechanical properties and preparation method thereof

Abstract

The application discloses a multiphase high-entropy alloy material with good high-temperature mechanical properties and a preparation method thereof. The application aims at the urgent demand for high-temperature mechanical properties of new materials in the field of high-temperature alloys. The multiphase high-entropy alloy material is composed of Al, Co, Cr, Fe, Nb and Ni elements, and the atomic percentage of the Al, Cr, Co, Fe, Nb and Ni is as follows: Al: 10.00at%-15.87at%, Co: 14.93at%-20.00at%, Cr: 14.93at%-20.00at%, Fe: 14.93at%-20.00at%, Nb: 2.96at%-10.00at% and Ni: 20.00at%-33.33at%. The high-entropy alloy contains BCC phase, FCC phase and Laves phase structures. The multiphase high-entropy alloy has reasonable components, high alloying degree and good high-temperature mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials and their preparation technology, specifically relating to an Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy material system with good high-temperature mechanical properties and its preparation method. Background Technology

[0002] In recent years, with the rapid development of the aerospace industry, nuclear energy technology, petrochemical industry, and other fields, the requirements for the high-temperature mechanical properties of high-temperature resistant metal materials have become increasingly stringent. Traditional metal materials often experience a decline in mechanical properties, plastic deformation, and oxidation corrosion at high temperatures, limiting their use in high-temperature applications. To overcome these problems, high-entropy alloys have been widely researched and developed as a new type of material. However, current research on high-temperature resistant high-entropy alloy materials is limited, and the existing high-entropy alloy systems are insufficient to meet the rapidly developing industrial demands. Therefore, there is an urgent need for a high-entropy alloy system with excellent high-temperature resistance and mechanical properties.

[0003] High-frequency vacuum induction melting is an advanced metal material preparation technology. It involves placing a metal sample in a vacuum environment, melting it using induction heating, and then rapidly solidifying it. It offers advantages such as high purity, excellent solubility and mixing capabilities, high melting temperature and rapid cooling rate, as well as high controllability and repeatability. High-frequency vacuum induction melting has wide applications in the research and preparation of high-entropy alloys. Summary of the Invention

[0004] This invention addresses the urgent need in the field of high-temperature alloys for new materials with good high-temperature mechanical properties by providing a multiphase high-entropy alloy with good high-temperature mechanical properties and its preparation method.

[0005] The multiphase high-entropy alloy material of the present invention, which has good high-temperature mechanical properties, is composed of Al, Co, Cr, Fe, Nb and Ni elements. The atomic percentages of Al, Cr, Co, Fe, Nb and Ni are Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 2.96at%~10.00at%, Ni: 20.00at%~33.33at%. Moreover, the multiphase high-entropy alloy contains BCC phase, FCC phase and Laves phase structure.

[0006] The preparation method of the multiphase high-entropy alloy material with good high-temperature mechanical properties of the present invention is carried out according to the following steps:

[0007] Step 1: Weigh out Al, Co, Cr, Fe, Nb, and Ni metal particles as raw materials according to the atomic percentage content of Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 2.96at%~10.00at%, and Ni: 20.00at%~33.33at%.

[0008] Step 2: Stack the metal granules from Step 1 evenly in the crucible according to their melting point from high to low and from top to bottom. Then, place the crucible into the outer crucible of the melting furnace and fix it in place. Turn on the water cooler and start the cooling circulation system. Close and lock the furnace cover of the melting furnace. Open the vacuum pump pre-evacuation valve and evacuate the furnace until the pressure inside the furnace is below 10 MPa. Close the vacuum valve and open the argon cylinder valve to fill the melting furnace with argon gas until the pressure is 0.05~0.08 MPa.

[0009] Step 3: Repeat step 2 for vacuuming and argon filling multiple times, then close the argon filling valve and the mechanical pump to complete the furnace cleaning.

[0010] Step 4: Turn on the high-frequency heating power supply of the melting furnace to start heating. The electrodes are heated by the coils wound around the crucible. The melting temperature is controlled by adjusting the current knob. The current increase rate is controlled at 1A / 5min. Gradually increase the current to 40~45A for melting. When the temperature reaches 1600℃~1750℃, hold it at that temperature to obtain molten metal.

[0011] Step 5: After the heat preservation is completed, control the current to decrease at a rate of 1A / 5min, gradually reduce the current, and lower the temperature inside the furnace to 1200℃~1300℃. When the current drops to 30~35A, rotate the crucible 3~5 degrees (°), then control the current to increase at a rate of 1A / 5min, and increase the current again to 40~45A for variable temperature melting.

[0012] Step 6: Repeat the variable-temperature melting process of Step 5 4 to 8 times;

[0013] Step 7: When the final temperature-changing melting is performed, rotate the crucible back to the initial position, control the current increase rate to 1A / 5min, and increase the current to 40~45A again for melting.

[0014] Step 8: After melting is complete, turn off the current and the heating power supply, keep the water chiller powered on, pour the molten alloy in the crucible into the water-cooled mold, let the metal in the water-cooled mold cool, open the vent valve, fill the furnace with gas to the standard atmospheric pressure, open the furnace cover and take out the high-entropy alloy ingot to obtain a multiphase high-entropy alloy material with good high-temperature mechanical properties.

[0015] The Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy prepared by this invention possesses FCC face-centered cubic, BCC body-centered cubic, and Laves multiphase structures. The BCC phase exhibits high strength and can withstand significant external forces, thus improving the overall strength of the material. The FCC phase has a unique crystal structure, causing the material to exhibit different mechanical responses under external forces, thereby affecting its strength, plasticity, toughness, and other mechanical properties. The Laves phase possesses high structural stability and excellent mechanical properties, improving the alloy's heat resistance, corrosion resistance, and mechanical properties. The multiphase mixture of FCC, BCC, and Laves phases endows the Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy prepared by this invention with good high-temperature resistance and exhibits excellent high-temperature hardness, high-temperature compression, and other high-temperature mechanical properties.

[0016] The multiphase high-entropy alloy material with good high-temperature mechanical properties and its preparation method have the following beneficial effects:

[0017] 1. This invention provides an Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy with excellent high-temperature mechanical properties. The high-entropy alloy material is mainly composed of FCC solid solution phase, BCC solid solution phase, and Laves phase, with a uniform microstructure. This alloy exhibits good mechanical properties at both room temperature and high temperature, and has broad application prospects in the field of high-temperature alloys.

[0018] 2. Adding aluminum (Al) to the alloy makes it easier to form an Al2O3 protective film during high-temperature oxidation, which helps to improve the alloy's high-temperature oxidation resistance.

[0019] 3. By adding niobium (Nb) to the alloy and melting it at a high temperature of 1600℃~1750℃, a phase composition in which FCC solid solution phase, BCC solid solution phase and Laves phase coexist is formed.

[0020] 4. The Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy of this invention is composed of FCC phase, BCC phase and Laves phase, and has both high strength and high hardness. Its application value is promising in the future.

[0021] 5. This invention provides a method for preparing high-entropy alloys through high-frequency vacuum induction melting process, which produces high-entropy alloy materials with good high-temperature mechanical properties, making up for the shortcomings of traditional alloys, and having excellent mechanical properties at room temperature and high temperature, and meeting the application requirements of high-temperature materials.

[0022] 6. During the smelting process, rotating the crucible allows the molten metal to flow fully within the crucible, accelerating element diffusion and promoting element mixing to obtain a high-entropy alloy material with uniform composition. Water cooling is used during the smelting process to rapidly cool the alloy, preserving the high-temperature Laves phase while maintaining the three-phase structure of FCC, BCC, and Laves phases, thus enhancing the alloy's strength.

[0023] 7. The repeated temperature-controlled melting process during the smelting process accelerates the diffusion and fusion between elements, promoting the formation of multiphases in the alloy. Attached Figure Description

[0024] Figure 1 The X-ray diffraction (XRD) pattern of the multiphase high-entropy alloy material prepared in Example 1;

[0025] Figure 2 The high-temperature hardness graph of the multiphase high-entropy alloy material prepared in Example 1 is shown.

[0026] Figure 3 The high-temperature compression curve of the multiphase high-entropy alloy material prepared in Example 1;

[0027] Figure 4 The TG-DSC curve of the multiphase high-entropy alloy material prepared in Example 1 is shown.

[0028] Figure 5 The high-temperature hardness graph is shown for the multiphase high-entropy alloy material prepared in Example 2. Detailed Implementation

[0029] Specific Implementation Method 1: The preparation method of the multiphase high-entropy alloy material with good high-temperature mechanical properties in this implementation method is carried out according to the following steps:

[0030] Step 1: Weigh out Al, Co, Cr, Fe, Nb, and Ni metal particles as raw materials according to the atomic percentage content of Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 2.96at%~10.00at%, and Ni: 20.00at%~33.33at%.

[0031] Step 2: Stack the metal granules from Step 1 evenly in the crucible according to their melting point from high to low and from top to bottom. Then, place the crucible into the outer crucible of the melting furnace and fix it in place. Turn on the water cooler and start the cooling circulation system. Close and lock the furnace cover of the melting furnace. Open the vacuum pump pre-evacuation valve and evacuate the furnace until the pressure inside the furnace is below 10 MPa. Close the vacuum valve and open the argon cylinder valve to fill the melting furnace with argon gas until the pressure is 0.05~0.08 MPa.

[0032] Step 3: Repeat step 2 for vacuuming and argon filling multiple times, then close the argon filling valve and the mechanical pump to complete the furnace cleaning.

[0033] Step 4: Turn on the high-frequency heating power supply of the melting furnace to start heating. The electrodes are heated by the coils wound around the crucible. The melting temperature is controlled by adjusting the current knob. The current increase rate is controlled at 1A / 5min. Gradually increase the current to 40~45A for melting. When the temperature reaches 1600℃~1750℃, hold it at that temperature to obtain molten metal.

[0034] Step 5: After the heat preservation is completed, control the current to decrease at a rate of 1A / 5min, gradually reduce the current, and lower the temperature inside the furnace to 1200℃~1300℃. When the current drops to 30~35A, rotate the crucible 3~5 degrees (°), then control the current to increase at a rate of 1A / 5min, and increase the current again to 40~45A for variable temperature melting.

[0035] Step 6: Repeat the variable-temperature melting process of Step 5 4 to 8 times;

[0036] Step 7: When the final temperature-changing melting is performed, rotate the crucible back to the initial position, control the current increase rate to 1A / 5min, and increase the current to 40~45A again for melting.

[0037] Step 8: After melting is complete, turn off the current and the heating power supply, keep the water chiller powered on, pour the molten alloy in the crucible into the water-cooled mold, let the metal in the water-cooled mold cool, open the vent valve, fill the furnace with gas to the standard atmospheric pressure, open the furnace cover and take out the high-entropy alloy ingot to obtain a multiphase high-entropy alloy material with good high-temperature mechanical properties.

[0038] In step five of this embodiment, the crucible can be manually rotated outside the furnace, enabling the crucible to rotate for each temperature-changing melting process, and allowing the liquid to be poured and cast inside the cavity.

[0039] In step one of this embodiment, the sum of the atomic percentages of the raw material metal elements is 100%.

[0040] In step eight of this embodiment, a water-cooled mold is used. Its main advantages are: first, water as a cooling medium has a cooling intensity that is tens or even hundreds of times that of compressed air, which can rapidly reduce the temperature of the mold; second, cooling water has a large specific heat capacity and low cost. As long as the cooling channel and cooling tower form a closed loop, it can be circulated in the cooling pipes and will not produce noise pollution like compressed air, thus achieving energy saving and environmental protection.

[0041] The Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy prepared in this embodiment has FCC face-centered cubic, BCC body-centered cubic and Laves multiphase structures. It has good high-temperature resistance and exhibits good high-temperature hardness, high-temperature compression and other high-temperature mechanical properties. It has considerable research value and development potential in the field of high-entropy alloys.

[0042] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the purity of the metal particles in step one is greater than 99.9%.

[0043] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that, in step one, Al, Co, Cr, Fe, Nb, and Ni metal particles are weighed as raw materials according to the atomic percentage content of Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 5.96at%~10.00at%, and Ni: 20.00at%~33.33at%.

[0044] Specific Implementation Method Four: This implementation method differs from one of the specific implementation methods one to three in that the smelting furnace described in step two is a high-frequency vacuum induction smelting furnace.

[0045] Specific Implementation Method 5: This implementation method differs from one of the specific implementation methods 1 to 4 in that the crucible mentioned in step 2 is a zirconium oxide crucible, a graphite crucible, or a cast iron crucible.

[0046] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the heat preservation time in step four is 20-30 minutes.

[0047] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that, in step five, when the current drops to 35A, the crucible is rotated 3 to 5 degrees, and the current increase rate is controlled at 1A / 5min. The current is then increased back to 45A for variable temperature melting.

[0048] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the variable temperature melting process in step six is ​​performed 4 to 6 times.

[0049] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that in step seven, the current growth rate is controlled to be 1A / 5min, and the current is increased to 45A again for melting.

[0050] Example 1: The preparation method of the multiphase high-entropy alloy material with good high-temperature mechanical properties in this example is carried out according to the following steps:

[0051] Step 1: Weigh out Al, Co, Cr, Fe, Nb, and Ni metal particles as raw materials according to the atomic percentage content of Al: 10.00at%, Co: 20.00at%, Cr: 20.00at%, Fe: 20.00at%, Nb: 10.00at%, and Ni: 20.00at%.

[0052] Step 2: Stack the metal granules from Step 1 evenly in the crucible according to their melting point from high to low and from top to bottom. Then, place the crucible into the outer crucible of the melting furnace and fix it in place. Turn on the water cooler and start the cooling circulation system. Close and lock the furnace cover of the melting furnace. Open the vacuum pump pre-evacuation valve and evacuate the furnace until the pressure inside the furnace is below 10 MPa. Close the vacuum valve and open the argon cylinder valve to fill the melting furnace with argon gas until the pressure is 0.06 MPa.

[0053] Step 3: Repeat step 2 for vacuuming and argon filling twice, then close the argon filling valve and the mechanical pump to complete the furnace cleaning.

[0054] Step 4: Turn on the high-frequency heating power supply of the melting furnace to start heating. The electrodes are heated by the coils wound around the crucible. The temperature is controlled by adjusting the current knob. The current increase rate is controlled at 1A / 5min. Gradually increase the current to 44A for melting. When the temperature reaches 1720℃, hold it at that temperature for 30min to obtain molten metal.

[0055] Step 5: After the heat preservation is completed, control the current to decrease at a rate of 1A / 5min, gradually reduce the current, and lower the temperature inside the furnace to 1200℃. When the current drops to 35A, rotate the crucible 5 degrees (rotate the cylindrical crucible in the vertical direction), then control the current to increase at a rate of 1A / 5min, and increase the current again to 44A for variable temperature melting.

[0056] Step 6: Repeat the variable-temperature melting process of Step 5 four times;

[0057] Step 7: When the final temperature-changing melting is performed, rotate the crucible back to the initial position, control the current increase rate to 1A / 5min, and then increase the current to 44A again for melting.

[0058] Step 8: After melting is complete, turn off the current and the heating power supply, keep the water chiller powered on to discharge the heat from the furnace, and allow the metal in the crucible to cool naturally. Then, open the vent valve, open the furnace cover, and take out the high-entropy alloy ingot to obtain a multiphase high-entropy alloy material with good high-temperature mechanical properties.

[0059] In step eight of this embodiment, the water-cooled mold is installed inside the high-frequency vacuum melting furnace. The mold is connected to a water chiller, which allows the liquid to be poured and cast within the furnace.

[0060] After the melting process in this embodiment is completed, a cylindrical alloy ingot is obtained by cooling. The oxide layer on its surface is removed by a wire cutting machine, and then it is cut into Al-Co-Cr-Fe-Nb-Ni high-entropy alloy blocks with a radius of about 45 mm and a thickness of about 30 mm.

[0061] The XRD pattern of the Al-Co-Cr-Fe-Nb-Ni high-entropy alloy prepared in this embodiment is as follows: Figure 1 As shown, the high-entropy alloy consists of FCC phase, BCC phase and Laves phase.

[0062] The high-temperature hardness curve of the Al-Co-Cr-Fe-Nb-Ni high-entropy alloy is as follows: Figure 2 As shown, the room temperature hardness of this Al-Co-Cr-Fe-Nb-Ni high-entropy alloy can reach 572.5 HV, and the hardness at 900℃ can reach 383.5 HV.

[0063] The high-entropy alloy Al-Co-Cr-Fe-Nb-Ni has the following high-temperature compression curve: Figure 3 As shown, the maximum pressure stress can reach 964 MPa at 800℃.

[0064] The high-entropy alloy Al-Co-Cr-Fe-Nb-Ni exhibits the following high-temperature stability TG and DSC curves: Figure 4 As shown, the DSC curve did not show a peak at 1200℃, indicating that the high-entropy alloy did not undergo a phase transformation at 1200℃; the TG curve did not show excessive fluctuations at 1200℃, meaning that the alloy's mass did not suffer excessive loss, indicating that the alloy has good high-temperature structural stability at 1200℃.

[0065] Example 2: The preparation method of the multiphase high-entropy alloy material with good high-temperature mechanical properties in this example is carried out according to the following steps:

[0066] Step 1: Weigh out Al, Co, Cr, Fe, Nb and Ni metal particles as raw materials according to the atomic percentage content of Al: 15.38at%, Co: 15.38at%, Cr: 15.38at%, Fe: 15.38at%, Nb: 6.15at%, Ni: 32.33at%.

[0067] Step 2: Stack the metal granules from Step 1 evenly in the crucible according to their melting point from high to low and from top to bottom. Then, place the crucible into the outer crucible of the melting furnace and fix it in place. Turn on the water cooler and start the cooling circulation system. Close and lock the furnace cover of the melting furnace. Open the vacuum pump pre-evacuation valve and evacuate the furnace until the pressure inside the furnace is below 10 MPa. Close the vacuum valve and open the argon cylinder valve to fill the melting furnace with argon gas until the pressure is 0.06 MPa.

[0068] Step 3: Repeat step 2 for vacuuming and argon filling twice, then close the argon filling valve and the mechanical pump to complete the furnace cleaning.

[0069] Step 4: Turn on the high-frequency heating power supply of the melting furnace to start heating. The electrodes are heated by the coils wound around the crucible. The temperature is controlled by adjusting the current knob. The current increase rate is controlled at 1A / 5min. Gradually increase the current to 45A for melting. When the temperature reaches 1750℃, hold it at that temperature for 30min to obtain molten metal.

[0070] Step 5: After the heat preservation is completed, control the current to decrease at a rate of 1A / 5min, gradually reduce the current, and lower the temperature inside the furnace to 1200℃. When the current drops to 35A, rotate the crucible 5 degrees and control the current to increase at a rate of 1A / 5min, then increase the current back to 45A for variable temperature melting.

[0071] Step 6: Repeat the variable-temperature melting process from step 5 five times;

[0072] Step 7: When the final temperature-changing melting is performed, rotate the crucible back to the initial position, control the current increase rate to 1A / 5min, and then increase the current to 45A again for melting.

[0073] Step 8: After melting is complete, turn off the current and the heating power supply, keep the water chiller powered on to discharge the heat from the furnace, and allow the metal in the crucible to cool naturally. Then, open the vent valve, open the furnace cover, and take out the high-entropy alloy ingot to obtain the multiphase high-entropy alloy material.

[0074] After the melting process in this embodiment is completed, a cylindrical alloy ingot is obtained by cooling. The oxide layer on its surface is removed by a wire cutting machine, and then it is cut into Al-Co-Cr-Fe-Nb-Ni high-entropy alloy blocks with a radius of about 45 mm and a thickness of about 30 mm.

[0075] The high-temperature hardness curve of the Al-Co-Cr-Fe-Nb-Ni high-entropy alloy is as follows: Figure 5 As shown, the room temperature hardness of this Al-Co-Cr-Fe-Ni-Nb high-entropy alloy can reach 620 HV.

[0076] Table 1. Comparison of chemical composition (at %) of Al-Co-Cr-Fe-Nb-Ni high-entropy alloy examples of the present invention

[0077] Relative molar mass M (g / mol) 26.98 58.93 51.99 55.85 92.91 58.69 Example 1 10.00 20.00 20.00 20.00 10.00 20.00 Example 2 15.38 15.38 15.38 15.38 6.15 32.33

[0078] Table 2. Values ​​of Vacuum Melting Parameters in Embodiments of the Invention

[0079] Example 1 44 30 4 Example 2 45 30 5

[0080] The multiphase high-entropy alloy material prepared in this embodiment consists of an FCC face-centered cubic solid solution phase, a BCC body-centered cubic solid solution phase, and a Laves phase. The Al-Co-Cr-Fe-Nb-Ni multiphase high-entropy alloy of this invention has a reasonable composition, a high degree of alloying, and excellent high-temperature mechanical properties, achieving a hardness of 572 HV, meeting the mechanical performance requirements for materials used in extreme environment components such as cutting tools, bearings, internal combustion engines, and drill bits. Furthermore, the preparation process of this invention is simple to operate and can achieve the preparation of large-sized ingots.

Claims

1. A method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties, characterized in that... The multiphase high-entropy alloy material with good high-temperature mechanical properties is composed of Al, Co, Cr, Fe, Nb and Ni elements. The atomic percentages of Al, Cr, Co, Fe, Nb and Ni are Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 2.96at%~10.00at%, Ni: 20.00at%~33.33at%. Furthermore, this multiphase high-entropy alloy contains BCC phase, FCC phase and Laves phase structures. The preparation method of the multiphase high-entropy alloy material with good high-temperature mechanical properties is carried out according to the following steps: Step 1: Weigh out Al, Co, Cr, Fe, Nb, and Ni metal particles as raw materials according to the atomic percentage content of Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 2.96at%~10.00at%, and Ni: 20.00at%~33.33at%. Step 2: Stack the metal granules from Step 1 evenly in the crucible according to their melting point from high to low and from top to bottom. Then, place the crucible into the outer crucible of the melting furnace and fix it in place. Turn on the water cooler and start the cooling circulation system. Close and lock the furnace cover of the melting furnace. Open the vacuum pump pre-evacuation valve and evacuate the furnace until the pressure inside the furnace is below 10 MPa. Close the vacuum valve and open the argon cylinder valve to fill the melting furnace with argon gas until the pressure is 0.05~0.08 MPa. Step 3: Repeat step 2 for vacuuming and argon filling multiple times, then close the argon filling valve and the mechanical pump to complete the furnace cleaning. Step 4: Turn on the high-frequency heating power supply of the melting furnace to start heating. The electrodes are heated by the coils wound around the crucible. The melting temperature is controlled by adjusting the current knob. The current increase rate is controlled at 1A / 5min. Gradually increase the current to 40~45A for melting. Heat the furnace to 1600℃~1750℃ and hold it at that temperature to obtain molten metal. Step 5: After the heat preservation is completed, control the current to decrease at a rate of 1A / 5min, gradually reduce the current, and lower the temperature inside the furnace to 1200℃~1300℃. When the current drops to 30~35A, rotate the crucible 3~5 degrees, then control the current to increase at a rate of 1A / 5min, and increase the current again to 40~45A for variable temperature melting. Step 6: Repeat the variable-temperature melting process of Step 5 4 to 8 times; Step 7: When the final temperature-changing melting is performed, rotate the crucible back to the initial position, control the current increase rate to 1A / 5min, and increase the current to 40~45A again for melting. Step 8: After melting is complete, turn off the current and the heating power supply, keep the water chiller powered on, pour the molten alloy in the crucible into the water-cooled mold, let the metal in the water-cooled mold cool, open the vent valve, fill the furnace with gas to the standard atmospheric pressure, open the furnace cover and take out the high-entropy alloy ingot to obtain a multiphase high-entropy alloy material with good high-temperature mechanical properties.

2. The method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties according to claim 1, characterized in that... In step one, the purity of the metal particles is greater than 99.9%.

3. The method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties according to claim 1, characterized in that... In step one, metal particles of Al, Co, Cr, Fe, Nb, and Ni are weighed as raw materials according to the atomic percentage content of Al: 10.00at%~15.87at%, Co: 14.93at%~20.00at%, Cr: 14.93at%~20.00at%, Fe: 14.93at%~20.00at%, Nb: 5.96at%~10.00at%, and Ni: 20.00at%~33.33at%.

4. The method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties according to claim 1, characterized in that... The smelting furnace mentioned in step two is a high-frequency vacuum induction smelting furnace.

5. The method for preparing a multiphase high-entropy alloy material with good high-temperature mechanical properties according to claim 1, characterized in that... The crucible mentioned in step two is a zirconium oxide crucible, a graphite crucible, or a cast iron crucible.

6. The method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties according to claim 1, characterized in that... The heat preservation time in step four is 20-30 minutes.

7. The method for preparing a multiphase high-entropy alloy material with good high-temperature mechanical properties according to claim 1, characterized in that... In step five, when the current drops to 35A, rotate the crucible 3-5 degrees, control the current increase rate to 1A / 5min, and increase the current back to 45A for variable temperature melting.

8. The method for preparing multiphase high-entropy alloy materials with good high-temperature mechanical properties according to claim 1, characterized in that... The variable-temperature melting process in step six is ​​repeated 4 to 6 times.

9. The method for preparing a multiphase high-entropy alloy material with good high-temperature mechanical properties according to claim 1, characterized in that... In step seven, the current increase rate is controlled at 1A / 5min, and the current is increased back to 45A for melting.

Images