High-temperature material with high toughness and method for preparing the same

Abstract

A high-temperature material with high toughness and a preparation method thereof, relate to the field of metal precision casting, and aim to solve the problem of poor room temperature toughness of existing Nb-Si alloy materials.The expression of the material is Nb-16Si-20Zr-2C-xW, and the method comprises the following steps: firstly, weighing raw materials Nb, Si, Zr, C and W; secondly, pre-treating the surface of the raw materials, melting, and obtaining a cast alloy ingot; thirdly, placing the ingot in a non-consumable vacuum arc furnace with an ultrasonic device to perform ultrasonic-assisted melting, and obtaining an ultrasonic-state alloy ingot; fourthly, filling quartz sand, heat treating, and cooling to obtain a heat-treated alloy; and fifthly, polishing the surface of the heat-treated alloy to remove the oxide skin, and the preparation is completed.The present application combines ultrasonic-assisted solidification with heat treatment, and significantly improves the toughness of the alloy material.The present application is used for preparing a high-toughness alloy material.

Description

Technical Field

[0001] This invention relates to the field of precision metal casting, and more particularly to a high-temperature material prepared by ultrasonic-assisted solidification and heat treatment, and a method thereof. Background Technology

[0002] As aerospace technology advances towards greater sophistication and specialization, the requirements for materials used in engine hot-section components are becoming increasingly stringent. Currently, the primary material for engine hot-section components is nickel-based superalloys, but the operating temperature of nickel-based single-crystal alloys reaches 85% of their melting point. Therefore, research into new high-temperature resistant material systems is necessary. Nb-Si alloys, with their low density and extremely high melting point, are well-suited for use as a next-generation engine material system. However, due to their high room-temperature brittleness and poor room-temperature toughness, they cannot meet the requirements for room-temperature assembly. Therefore, toughening Nb-Si alloys has become a critical issue. Improving the room-temperature toughness of Nb-Si alloys would allow for their application in aero-engines. Summary of the Invention

[0003] The present invention aims to solve the problem of poor room temperature toughness of existing Nb-Si alloy materials and to provide a high-temperature alloy material and its preparation method.

[0004] The high-toughness high-temperature material of the present invention is expressed as Nb-16Si-20Zr-2C-xW, where x = 0.1, 0.5, 1 or 2.

[0005] The present invention discloses a method for preparing a high-toughness high-temperature material, comprising the following steps:

[0006] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of elements in the Nb-16Si-20Zr-2C-xW alloy; where x = 0.1, 0.5, 1, or 2.

[0007] 2. The surface of the raw materials is pretreated and placed into a crucible in a non-consumable vacuum arc furnace. At the same time, sponge titanium is added to an adjacent crucible. After the non-consumable vacuum arc furnace is evacuated, inert gas is introduced for melting. After cooling, a cast Nb-16Si-20Zr-2C-xW alloy ingot is obtained.

[0008] 3. Place the alloy ingot obtained in step 2 into a water-cooled copper crucible in a non-consumable vacuum arc furnace equipped with an ultrasonic device, close the furnace door, open the vacuum gauge, argon valve and charging valve, and charge argon into the non-consumable vacuum arc furnace. Then close the argon valve and charging valve, evacuate the furnace, and then start melting. Melt only once. Apply ultrasonic action during the process of reducing the melting current. Then reduce the current to 0A and then turn off the ultrasonic. After cooling, obtain an ultrasonic Nb-16Si-20Zr-2C-xW alloy ingot.

[0009] Fourth, first lay a layer of quartz sand at the bottom of the alumina crucible, then put in the ultrasonic Nb-16Si-20Zr-2C-xW alloy ingot obtained in step three, and then completely bury the alloy ingot with quartz sand. At this time, the quartz sand fills part of the alumina crucible. Then place sponge titanium on the quartz sand and continue to fill the quartz sand until the entire alumina crucible is filled.

[0010] Heat the heat treatment furnace until the temperature reaches 1200-1400℃. Place the alumina crucible on the refractory bricks and put the refractory bricks together with the alumina crucible into the heat treatment furnace. Maintain the temperature at 1200-1400℃ for 30 hours. Then turn off the heating and let the furnace cool to obtain the heat-treated Nb-16Si-20Zr-2C-xW alloy.

[0011] 5. Remove the oxide scale from the surface of the heat-treated Nb-16Si-20Zr-2C-xW alloy by sanding with sandpaper, and the preparation is complete.

[0012] Furthermore, the purity of the raw materials in step one is all above 99.95%.

[0013] Furthermore, the method for pre-treating the surface of the raw material in step two is as follows: the surface of the raw material is sanded with sandpaper, and the raw material is placed in an ethanol solution for the first ultrasonic cleaning. After the first cleaning, the raw material is placed in deionized water for the second ultrasonic cleaning. Then, the raw material is dried with hot air.

[0014] Furthermore, in step two, before smelting, the sponge titanium in the crucible is first melted to absorb oxygen.

[0015] Furthermore, in step two, the pretreated raw materials are placed into the crucible inside the non-consumable vacuum arc furnace in the order of W, C, Si, Zr, and Nb from bottom to top.

[0016] Furthermore, the melting process described in step two involves increasing the current to 650A and maintaining it at 650A for 30-40 seconds, followed by cooling.

[0017] Furthermore, after melting once in step two, the alloy ingot is flipped 180° and melted again, and this melting process is repeated 5 times.

[0018] Furthermore, in step three, the melting process involves raising the current to 650A and maintaining it at 650A for 30-40 seconds, followed by cooling.

[0019] Furthermore, in step three, when the melting current is reduced from 650A to 350A, ultrasonic waves are applied for 100 seconds.

[0020] Furthermore, in step three, the melting current decreases at a rate of 50A every 10 seconds.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention employs an ultrasonic-assisted solidification method to alter the microstructure of the alloy, thereby improving the mechanical properties of high-temperature Nb-Si materials. Introducing ultrasound into the high-temperature alloy melt during the solidification stage increases the supercooling during solidification and breaks down some coarse grains and phase structures formed during solidification, thus achieving grain refinement and strengthening. Furthermore, ultrasound induces an acoustic flow effect in the high-temperature alloy melt, promoting the diffusion of different elements and reducing element segregation. This enhances the mechanical properties of the alloy, thereby improving the mechanical properties of the high-temperature material.

[0023] 2. In the preparation method of this invention, after ultrasonic-assisted solidification of the alloy melt, a high-temperature heat treatment process is used for subsequent processing of the alloy. Since the Nb-Si alloy melt in this invention is a high-temperature alloy melt, ultrasonic waves are typically introduced indirectly. However, during the propagation of ultrasonic waves, attenuation occurs in the high-temperature alloy melt, resulting in different effects between the top and bottom of the alloy ingot and generating an uneven microstructure in the Nb-Si alloy, leading to differences in mechanical properties at different locations. Subsequent high-temperature heat treatment of the ultrasonically solidified alloy ingot can make the internal microstructure of the ingot more uniform, reduce the differences in mechanical properties at different locations, and decrease the anisotropy of mechanical properties in the alloy ingot.

[0024] High-temperature heat treatment of Nb-Si superalloys transforms the brittle primary silicide phase into a eutectoid structure of silicide and Nbss phases, which improves the alloy's toughness. Furthermore, high-temperature heat treatment can reduce the silicide phase content and increase the content of pseudo-matrix solid solutions in the alloy microstructure to some extent.

[0025] The method of this invention has a simple process, a short preparation cycle, and is relatively easy to implement. Attached Figure Description

[0026] Figure 1 The image shows the microstructure of the Nb-16Si-20Zr-2C-0.1W high-temperature material prepared in Example 1.

[0027] Figure 2 The image shows the microstructure of the Nb-16Si-20Zr-2C-0.5W high-temperature material prepared in Example 2.

[0028] Figure 3 The image shows the microstructure of the Nb-16Si-20Zr-2C-1W high-temperature material prepared in Example 3.

[0029] Figure 4 The image shows the microstructure of the Nb-16Si-20Zr-2C-2W high-temperature material prepared in Example 4.

[0030] Figure 5 Microstructure of the ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot prepared for Comparative Example 1;

[0031] Figure 6 The room temperature fracture toughness of the Nb-Si-Zr-C-xW high-temperature materials prepared in Examples 1 to 4 and Comparative Example 1 is shown. Detailed Implementation

[0032] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0033] Specific implementation method one: The expression of the high-toughness high-temperature material in this implementation method is Nb-16Si-20Zr-2C-xW, where x = 0.1, 0.5, 1 or 2.

[0034] Specific Implementation Method Two: This implementation method for preparing a high-toughness high-temperature material includes the following steps:

[0035] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of elements in the Nb-16Si-20Zr-2C-xW alloy; where x = 0.1, 0.5, 1, or 2.

[0036] 2. The surface of the raw materials is pretreated and placed into a crucible in a non-consumable vacuum arc furnace. At the same time, sponge titanium is added to an adjacent crucible. After the non-consumable vacuum arc furnace is evacuated, inert gas is introduced for melting. After cooling, a cast Nb-16Si-20Zr-2C-xW alloy ingot is obtained.

[0037] 3. Place the alloy ingot obtained in step 2 into a water-cooled copper crucible in a non-consumable vacuum arc furnace equipped with an ultrasonic device, close the furnace door, open the vacuum gauge, argon valve and charging valve, and charge argon into the non-consumable vacuum arc furnace. Then close the argon valve and charging valve, evacuate the furnace, and then start melting. Melt only once. Apply ultrasonic action during the process of reducing the melting current. Then reduce the current to 0A and then turn off the ultrasonic. After cooling, obtain an ultrasonic Nb-16Si-20Zr-2C-xW alloy ingot.

[0038] Fourth, first lay a layer of quartz sand at the bottom of the alumina crucible, then put in the ultrasonic Nb-16Si-20Zr-2C-xW alloy ingot obtained in step three, and then completely bury the alloy ingot with quartz sand. At this time, the quartz sand fills part of the alumina crucible. Then place sponge titanium on the quartz sand and continue to fill the quartz sand until the entire alumina crucible is filled.

[0039] Heat the heat treatment furnace until the temperature reaches 1200-1400℃. Place the alumina crucible on the refractory bricks and put the refractory bricks together with the alumina crucible into the heat treatment furnace. Maintain the temperature at 1200-1400℃ for 30 hours. Then turn off the heating and let the furnace cool to obtain the heat-treated Nb-16Si-20Zr-2C-xW alloy.

[0040] 5. Remove the oxide scale from the surface of the heat-treated Nb-16Si-20Zr-2C-xW alloy by sanding with sandpaper, and the preparation is complete.

[0041] This invention, after ultrasonic-assisted solidification, applies post-heat treatment to the ultrasonically solidified alloy ingot to further improve the alloy's microstructure. Because the effect of unidirectional ultrasound gradually weakens with increasing propagation distance, the ultrasonic waves become unevenly distributed, leading to inhomogeneous microstructure and varying mechanical properties in the titanium alloy. Heat treatment following ultrasonic treatment helps homogenize the alloy's microstructure and alters the shapes of different phases in the matrix, softening sharp edges. This avoids stress concentration and further enhances mechanical properties.

[0042] High-temperature heat treatment makes the edges of different phases in Nb-Si alloys more rounded, effectively smoothing the edges of many regular, polygonal primary silicide phases in the ultrasonic Nb-Si alloy. These regularly shaped primary silicide phases have sharp edges and smooth boundaries, causing significant cutting and stress concentration in the Nb-Si superalloy matrix. When failure cracks propagate, these stress-concentrated areas form new crack initiations and induce further crack propagation, adversely affecting the alloy's mechanical properties, especially its toughness. Heat treatment, however, makes the phase boundaries more rounded, reducing stress concentration and this cutting effect, thereby improving the alloy's mechanical properties.

[0043] In Nb-Si alloys, the Nbss phase, acting as a toughening phase, is beneficial to the alloy's toughness. Conversely, the silicide phase, being a brittle phase, easily induces crack propagation within the brittle silicide phase, thus altering the alloy's toughness. However, after high-temperature heat treatment, the primary silicide phase in Nb-Si superalloys dissolves, forming a eutectoid structure of Nbss and silicide phases. Alternatively, it may form a specific microstructure that influences crack propagation direction and increases the Nbss phase content, thereby improving the alloy's mechanical properties, particularly its toughness.

[0044] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method Two in that the purity of the raw materials in step one is all above 99.95%. Everything else is the same as in Specific Implementation Method Two.

[0045] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods Two or Three in that the surface pretreatment method for the raw material in step two is as follows: the surface of the raw material is sanded with sandpaper, and the raw material is placed in an ethanol solution for a first ultrasonic cleaning. After the first cleaning, the raw material is placed in deionized water for a second ultrasonic cleaning, and then the raw material is dried with hot air. Everything else is the same as in Specific Implementation Methods Two or Three.

[0046] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Two to Four in that, in step two, before smelting, the sponge titanium in the crucible is first melted to absorb oxygen. Everything else is the same as in Specific Implementation Methods Two to Four.

[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Two to Five in that the pretreated raw materials in step two are placed into the crucible inside the non-consumable vacuum arc furnace in the order of W, C, Si, Zr, and Nb from bottom to top. Everything else is the same as in Specific Implementation Methods Two to Five.

[0048] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Two to Six in that: in step two, the melting process involves increasing the current to 650A and maintaining it at 650A for 30-40 seconds. Everything else is the same as in Specific Implementation Methods Two to Six.

[0049] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that: after melting once in step two, the alloy ingot is flipped 180° and melted again, and this melting process is repeated 5 times. Everything else is the same as in Specific Implementation Method Seven.

[0050] This implementation method ensures that the alloy ingot has a uniform composition.

[0051] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Two to Eight in that: in step three, the melting process involves increasing the current to 650A and maintaining it at 650A for 30-40 seconds. Everything else is the same as in Specific Implementation Methods Two to Eight.

[0052] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that, in step three, when the melting current is reduced from 650A to 350A, ultrasonic waves are applied for 100 seconds. Everything else is the same as in Specific Implementation Method Nine.

[0053] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Method Ten in that the melting current decreases at a rate of 50A every 10 seconds in step three. Everything else is the same as in Specific Implementation Method Ten.

[0054] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0055] Example 1:

[0056] The preparation method of the high-toughness high-temperature material in this embodiment includes the following steps:

[0057] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of the expression Nb-16Si-20Zr-2C-0.1W. The atomic percentage composition is as follows: Nb is 61.9%, Si is 16%, Zr is 20%, C is 2%, and W is 0.1%.

[0058] The Nb, Si, and Zr elements are all 1-3 mm irregular particles with a purity of 99.9% or higher. The C elements are C powder with a purity of 99.9% or higher. Additional pieces of sponge titanium need to be weighed and placed in the non-consumable vacuum arc furnace to absorb oxygen and increase the vacuum level within the furnace.

[0059] 2. Surface cleaning of various elemental raw materials is performed to prevent the introduction of impurities during the smelting process. The surface of the raw materials is polished with 240# SiC wet sandpaper, and then placed in an ethanol solution for the first ultrasonic cleaning. The first cleaning time is 10 minutes, the power is 100W, and the frequency is 25kHz. After the first cleaning, the raw materials are placed in deionized water for a second ultrasonic cleaning. The second cleaning time is 12 minutes, the power is 100W, and the frequency is 30kHz. After cleaning, the raw materials are dried with hot air. C powder is wrapped with a small amount of Al foil and no surface cleaning is performed.

[0060] 3. Place the dried raw materials into the crucibles inside the non-consumable vacuum arc furnace in the following order from bottom to top: W, C, Si, Zr, Nb. Although elemental W has a high density, due to the low content of added W, elemental W is placed at the bottom, and sponge titanium for oxygen absorption is placed in the adjacent crucible.

[0061] During the smelting process, the non-consumable vacuum arc furnace is first evacuated to a vacuum level of 4×10. -3 At step 1, open the argon valve and introduce high-purity argon into the non-consumable vacuum arc furnace (NCA) to increase the furnace pressure. When the furnace pressure reaches -0.05 MPa, slowly increase the melting current from 0 A to 650 A, while maintaining a circulating cooling water flow rate of 2.5 m / s. First, melt and solidify the sponge titanium using an electric arc to absorb residual oxygen in the NCA and increase the vacuum level, preventing oxidation during melting. Then, melt the raw materials. When the current reaches 650 A, maintain this position for 40 seconds, followed by cooling. To ensure uniform alloy ingot composition, use the NCA's built-in robotic arm to rotate the ingot 180° and melt it again. Repeat this melting process five times before cooling. The resulting Nb-16Si-20Zr-2C-0.1W alloy ingot is then obtained in its as-cast state.

[0062] 4. Place the alloy ingot melted in step 3 into the water-cooled copper crucible of a non-consumable vacuum arc furnace equipped with an ultrasonic device (i.e., install an ultrasonic amplitude rod below the water-cooled copper crucible of the non-consumable vacuum arc furnace) and close the furnace door. Simultaneously open the vacuum gauge, argon valve, and charging valve to charge the non-consumable vacuum arc furnace with inert argon gas for a total of 20 seconds. After charging is completed, close the argon valve and charging valve on the furnace body. Then, open the vacuum pump to evacuate the furnace body. When the vacuum count value drops to -2 MPa, close the vacuum gauge and vacuum pump. Begin melting the alloy ingot, controlling the melting current to slowly increase from 0A to 650A and maintain it at 650A for 40 seconds. Melt only once. During the final controlled current decrease, first reduce the current from 650A to 350A (decreasing by 50A every 10 seconds). When the current decreases to 350A, begin applying ultrasonic waves for 100 seconds. After the ultrasonic waves are applied, the current is slowly reduced to 0A, and the ultrasonic device is turned off. After the non-consumable vacuum arc furnace cools down, an ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot is obtained.

[0063] 5. The prepared ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot was placed into an alumina crucible, and completely buried in quartz sand using the sand-burying method, ensuring that the quartz sand filled half the volume of the crucible. Then, two pieces of titanium sponge were placed on top of the buried quartz sand, and quartz sand was continued to be buried until the entire alumina crucible was filled. The heating program was entered into the heat treatment furnace and heating was started. When the temperature in the heat treatment furnace reached 1300℃, the alumina crucible was placed on refractory bricks, and the refractory bricks and the alumina crucible were placed together into the heat treatment furnace. The temperature was maintained at 1300℃ for 30 hours. After that, the heating was turned off, and the alloy ingot was allowed to cool with the furnace. The alloy ingot was then removed from the crucible to obtain the heat-treated Nb-16Si-20Zr-2C-0.1W alloy. The purpose of placing two pieces of titanium sponge is that, in the high-temperature environment of the heat treatment furnace, the titanium sponge can further absorb oxygen and slow down the oxidation of the Nb-Si high-temperature alloy ingot in the alumina crucible.

[0064] 6. Use 400# SiC wet sandpaper to polish away the surface oxide scale of the heat-treated Nb-16Si-20Zr-2C-0.1W alloy, and the final preparation is completed.

[0065] Comparative Example 1:

[0066] The difference between this comparative example and Example 1 is that step five is omitted, i.e., only ultrasonic-assisted solidification is applied without heat treatment.

[0067] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of the expression Nb-16Si-20Zr-2C-0.1W. The atomic percentage composition is as follows: Nb is 61.9%, Si is 16%, Zr is 20%, C is 2%, and W is 0.1%.

[0068] The Nb, Si, and Zr elements are all 1-3 mm irregular particles with a purity of 99.9% or higher. The C elements are C powder with a purity of 99.9% or higher. Additional pieces of sponge titanium need to be weighed and placed in the non-consumable vacuum arc furnace to absorb oxygen and increase the vacuum level within the furnace.

[0069] 2. Surface cleaning of various elemental raw materials is performed to prevent the introduction of impurities during the smelting process. The surface of the raw materials is polished with 240# SiC wet sandpaper, and then placed in an ethanol solution for the first ultrasonic cleaning. The first cleaning time is 10 minutes, the power is 100W, and the frequency is 25kHz. After the first cleaning, the raw materials are placed in deionized water for a second ultrasonic cleaning. The second cleaning time is 12 minutes, the power is 100W, and the frequency is 30kHz. After cleaning, the raw materials are dried with hot air. C powder is wrapped with a small amount of Al foil and no surface cleaning is performed.

[0070] 3. Place the dried raw materials into the crucibles inside the non-consumable vacuum arc furnace in the following order from bottom to top: W, C, Si, Zr, Nb. Although elemental W has a high density, due to the low content of added W, elemental W is placed at the bottom, and sponge titanium for oxygen absorption is placed in the adjacent crucible.

[0071] During the smelting process, the non-consumable vacuum arc furnace is first evacuated to a vacuum level of 4×10. -3 At step 1, open the argon valve and introduce high-purity argon into the non-consumable vacuum arc furnace (NCA) to increase the furnace pressure. When the furnace pressure reaches -0.05 MPa, slowly increase the melting current from 0 A to 650 A, while maintaining a circulating cooling water flow rate of 2.5 m / s. First, melt and solidify the sponge titanium using an electric arc to absorb residual oxygen in the NCA and increase the vacuum level, preventing oxidation during melting. Then, melt the raw materials. When the current reaches 650 A, maintain this position for 40 seconds, followed by cooling. To ensure uniform alloy ingot composition, use the NCA's built-in robotic arm to rotate the ingot 180° and melt it again. Repeat this melting process five times before cooling. The resulting Nb-16Si-20Zr-2C-0.1W alloy ingot is then obtained in its as-cast state.

[0072] 4. Place the alloy ingot melted in step 3 into the water-cooled copper crucible of a non-consumable vacuum arc furnace equipped with an ultrasonic device (i.e., install an ultrasonic amplitude rod below the water-cooled copper crucible of the non-consumable vacuum arc furnace) and close the furnace door. Simultaneously open the vacuum gauge, argon valve, and charging valve to charge the non-consumable vacuum arc furnace with inert argon gas for a total of 20 seconds. After charging is completed, close the argon valve and charging valve on the furnace body. Then, open the vacuum pump to evacuate the furnace body. When the vacuum count value drops to -2 MPa, close the vacuum gauge and vacuum pump. Begin melting the alloy ingot, controlling the melting current to slowly increase from 0A to 650A and maintain it at 650A for 40 seconds. Melt only once. During the final controlled current decrease, first reduce the current from 650A to 350A (decreasing by 50A every 10 seconds). When the current decreases to 350A, begin applying ultrasonic waves for 100 seconds. After the ultrasonic waves are applied, the current is slowly reduced to 0A, and the ultrasonic device is turned off. After the non-consumable vacuum arc furnace cools down, an ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot is obtained.

[0073] Example 2:

[0074] The preparation method of the high-toughness high-temperature material in this embodiment includes the following steps:

[0075] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of the expression Nb-16Si-20Zr-2C-0.5W. The atomic percentage composition is as follows: Nb is 61.5%, Si is 16%, Zr is 20%, C is 2%, and W is 0.5%.

[0076] The Nb, Si, and Zr elements are all 1-3 mm irregular particles with a purity of 99.9% or higher. The C elements are C powder with a purity of 99.9% or higher. Additional pieces of sponge titanium need to be weighed and placed in the vacuum non-consumable arc furnace to absorb oxygen and increase the vacuum level within the furnace.

[0077] 2. Surface cleaning of various elemental raw materials is performed to prevent the introduction of impurities during the smelting process. The surface of the raw materials is polished with 240# SiC wet sandpaper, and then placed in an ethanol solution for the first ultrasonic cleaning. The first cleaning time is 10 minutes, the power is 100W, and the frequency is 25kHz. After the first cleaning, the raw materials are placed in deionized water for a second ultrasonic cleaning, which takes 12 minutes, has a power of 100W, and a frequency of 30kHz. After cleaning, the raw materials are dried using hot air. C powder is wrapped with a small amount of Al foil and does not undergo surface cleaning.

[0078] 3. The dried raw materials are placed into the crucible in the non-consumable vacuum arc furnace in the order of W, C, Si, Zr and Nb from bottom to top. Although the density of elemental W is very high, the content of added W is low, so elemental W is placed at the bottom, and the sponge titanium for oxygen absorption is placed in the adjacent crucible.

[0079] During the smelting process, the non-consumable vacuum arc furnace is first evacuated to a vacuum level of 4×10. -3 At step 1, open the argon valve and introduce high-purity argon into the non-consumable vacuum arc furnace (NCA) to increase the furnace pressure. When the furnace pressure reaches -0.05 MPa, slowly increase the melting current from 0 A to 650 A, while maintaining a circulating cooling water flow rate of 2.5 m / s. First, melt and solidify the sponge titanium using an electric arc to absorb residual oxygen in the NCA and increase the vacuum level, preventing oxidation during melting. Then, melt the raw materials. When the current reaches 650 A, maintain this position for 40 seconds, followed by cooling. To ensure uniform alloy ingot composition, use the NCA's built-in robotic arm to rotate the ingot 180° and melt it again. Repeat this melting process five times before cooling. The resulting Nb-16Si-20Zr-2C-0.5W alloy ingot is then obtained in its as-cast state.

[0080] 4. Place the alloy ingot melted in step 3 into the water-cooled copper crucible of a non-consumable vacuum arc furnace equipped with an ultrasonic device (i.e., install an ultrasonic amplitude rod below the water-cooled copper crucible of the non-consumable vacuum arc furnace) and close the furnace door. Simultaneously open the vacuum gauge, argon valve, and charging valve to charge the non-consumable vacuum arc furnace with inert argon gas for a total of 20 seconds. After charging is completed, close the argon valve and charging valve on the furnace body. Then, open the vacuum pump to evacuate the furnace body. When the vacuum count value drops to -2 MPa, close the vacuum gauge and vacuum pump. Begin melting the alloy ingot, controlling the melting current to slowly increase from 0A to 650A and maintain it at 650A for 40 seconds. Melt only once. During the final controlled current decrease, first reduce the current from 650A to 350A (decreasing by 50A every 10 seconds). When the current decreases to 350A, begin applying ultrasonic waves for 100 seconds. After the ultrasonic waves are applied, the current is slowly reduced to 0A, and the ultrasonic device is turned off. After the non-consumable vacuum arc furnace cools down, an ultrasonic Nb-16Si-20Zr-2C-0.5W alloy ingot is obtained.

[0081] 5. The prepared ultrasonic Nb-16Si-20Zr-2C-0.5W alloy ingot was placed into an alumina crucible, and completely buried in quartz sand using the sand-burying method, ensuring that the quartz sand filled half the volume of the crucible. Then, two pieces of titanium sponge were placed on top of the buried quartz sand, and quartz sand was continued to be buried until the entire alumina crucible was filled. The heating program was entered into the heat treatment furnace and heating was started. When the temperature in the heat treatment furnace reached 1300℃, the alumina crucible was placed on refractory bricks, and the refractory bricks and the alumina crucible were placed together into the heat treatment furnace. The temperature was maintained at 1300℃ for 30 hours. After that, the heating was turned off, and the alloy ingot was allowed to cool with the furnace. The alloy ingot was then removed from the crucible to obtain the heat-treated Nb-16Si-20Zr-2C-0.5W alloy. The purpose of placing two pieces of titanium sponge is that, in the high-temperature environment of the heat treatment furnace, the titanium sponge can further absorb oxygen and slow down the oxidation of the Nb-Si high-temperature alloy ingot in the alumina crucible.

[0082] 7. Use 400# SiC wet sandpaper to polish away the surface oxide scale of the heat-treated Nb-16Si-20Zr-2C-0.5W alloy, and the final preparation is completed.

[0083] Example 3:

[0084] The preparation method of the high-toughness high-temperature material in this embodiment includes the following steps:

[0085] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentages of the expression Nb-16Si-20Zr-2C-1W. The atomic percentage composition is as follows: Nb is 61.5%, Si is 16%, Zr is 20%, C is 2%, and W is 1%.

[0086] The Nb, Si, and Zr elements are all 1-3 mm irregular particles with a purity of 99.9% or higher. The C elements are C powder with a purity of 99.9% or higher. Additional pieces of sponge titanium need to be weighed and placed in the vacuum non-consumable arc furnace to absorb oxygen and increase the vacuum level within the furnace.

[0087] 2. Surface cleaning of various elemental raw materials is performed to prevent the introduction of impurities during the smelting process. The surface of the raw materials is polished with 240# SiC wet sandpaper, and then placed in an ethanol solution for the first ultrasonic cleaning. The first cleaning time is 10 minutes, the power is 100W, and the frequency is 25kHz. After the first cleaning, the raw materials are placed in deionized water for a second ultrasonic cleaning, which takes 12 minutes, has a power of 100W, and a frequency of 30kHz. After cleaning, the raw materials are dried using hot air. C powder is wrapped with a small amount of Al foil and does not undergo surface cleaning.

[0088] 3. The dried raw materials are placed into the crucible in the non-consumable vacuum arc furnace in the order of W, C, Si, Zr and Nb from bottom to top. Although the density of elemental W is very high, the content of added W is low, so elemental W is placed at the bottom, and the sponge titanium for oxygen absorption is placed in the adjacent crucible.

[0089] During the smelting process, the non-consumable vacuum arc furnace is first evacuated to a vacuum level of 4×10. -3 At step 1, open the argon valve and introduce high-purity argon into the non-consumable vacuum arc furnace (NCA) to increase the furnace pressure. When the furnace pressure reaches -0.05 MPa, slowly increase the melting current from 0 A to 650 A, while maintaining a circulating cooling water flow rate of 2.5 m / s. First, melt and solidify the sponge titanium using an electric arc to absorb residual oxygen in the NCA and increase the vacuum level, preventing oxidation during melting. Then, melt the raw materials. When the current reaches 650 A, maintain this position for 40 seconds, followed by cooling. To ensure uniform alloy ingot composition, use the NCA's built-in robotic arm to rotate the ingot 180° and melt it again. Repeat this melting process five times before cooling. The resulting Nb-16Si-20Zr-2C-1W alloy ingot is then obtained in its as-cast state.

[0090] 4. Place the alloy ingot melted in step 3 into the water-cooled copper crucible of a non-consumable vacuum arc furnace equipped with an ultrasonic device (i.e., install an ultrasonic amplitude rod below the water-cooled copper crucible of the non-consumable vacuum arc furnace) and close the furnace door. Simultaneously open the vacuum gauge, argon valve, and charging valve to charge the non-consumable vacuum arc furnace with inert argon gas for a total of 20 seconds. After charging is completed, close the argon valve and charging valve on the furnace body. Then, open the vacuum pump to evacuate the furnace body. When the vacuum count value drops to -2 MPa, close the vacuum gauge and vacuum pump. Begin melting the alloy ingot, controlling the melting current to slowly increase from 0A to 650A and maintain it at 650A for 40 seconds. Melt only once. During the final controlled current decrease, first reduce the current from 650A to 350A (decreasing by 50A every 10 seconds). When the current decreases to 350A, begin applying ultrasonic waves for 100 seconds. After the ultrasonic waves are applied, the current is slowly reduced to 0A, and the ultrasonic device is turned off. After the non-consumable vacuum arc furnace cools down, an ultrasonic Nb-16Si-20Zr-2C-1W alloy ingot is obtained.

[0091] 5. The prepared ultrasonic Nb-16Si-20Zr-2C-1W alloy ingot was placed into an alumina crucible, and completely buried in quartz sand using the sand-burying method, ensuring that the quartz sand filled half the volume of the crucible. Then, two pieces of titanium sponge were placed on top of the buried quartz sand, and then quartz sand was continued to be buried until the entire alumina crucible was filled with quartz sand. The heating program was entered into the heat treatment furnace and heating was started. When the temperature in the heat treatment furnace reached 1300℃, the alumina crucible was placed on refractory bricks, and the refractory bricks and the alumina crucible were placed together into the heat treatment furnace. The temperature was maintained at 1300℃ for 30 hours. After that, the heating was turned off, and the alloy ingot was allowed to cool with the furnace. The alloy ingot was then removed from the crucible to obtain the heat-treated Nb-16Si-20Zr-2C-1W alloy. The purpose of placing two pieces of titanium sponge is that, in the high-temperature environment of the heat treatment furnace, the titanium sponge can further absorb oxygen and slow down the oxidation of the Nb-Si high-temperature alloy ingot in the alumina crucible.

[0092] 6. Use 400# SiC wet sandpaper to polish away the surface oxide scale of the heat-treated Nb-16Si-20Zr-2C-1W alloy, and the final preparation is completed.

[0093] Example 4:

[0094] The preparation method of the high-toughness high-temperature material in this embodiment includes the following steps:

[0095] I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentages of the expression Nb-16Si-20Zr-2C-2W. The atomic percentage composition is as follows: Nb is 61.5%, Si is 16%, Zr is 20%, C is 2%, and W is 2%.

[0096] The Nb, Si, and Zr elements are all 1-3 mm irregular particles with a purity of 99.9% or higher. The C elements are C powder with a purity of 99.9% or higher. Additional pieces of sponge titanium need to be weighed and placed in the vacuum non-consumable arc furnace to absorb oxygen and increase the vacuum level within the furnace.

[0097] 2. Surface cleaning of various elemental raw materials is performed to prevent the introduction of impurities during the smelting process. The surface of the raw materials is polished with 240# SiC wet sandpaper, and then placed in an ethanol solution for the first ultrasonic cleaning. The first cleaning time is 10 minutes, the power is 100W, and the frequency is 25kHz. After the first cleaning, the raw materials are placed in deionized water for a second ultrasonic cleaning, which takes 12 minutes, has a power of 100W, and a frequency of 30kHz. After cleaning, the raw materials are dried using hot air. C powder is wrapped with a small amount of Al foil and does not undergo surface cleaning.

[0098] 3. The dried raw materials are placed into the crucible in the non-consumable vacuum arc furnace in the order of W, C, Si, Zr and Nb from bottom to top. Although the density of elemental W is very high, the content of added W is low, so elemental W is placed at the bottom, and the sponge titanium for oxygen absorption is placed in the adjacent crucible.

[0099] During the smelting process, the non-consumable vacuum arc furnace is first evacuated to a vacuum level of 4×10. -3 At step 1, open the argon valve and introduce high-purity argon into the non-consumable vacuum arc furnace (NCA) to increase the furnace pressure. When the furnace pressure reaches -0.05 MPa, slowly increase the melting current from 0 A to 650 A, while maintaining a circulating cooling water flow rate of 2.5 m / s. First, melt and solidify the sponge titanium using an electric arc to absorb residual oxygen in the NCA and increase the vacuum level, preventing oxidation during melting. Then, melt the raw materials. When the current reaches 650 A, maintain this position for 40 seconds, followed by cooling. To ensure uniform alloy ingot composition, use the NCA's built-in robotic arm to rotate the ingot 180° and melt it again. Repeat this melting process five times before cooling. The resulting Nb-16Si-20Zr-2C-2W alloy ingot is then obtained in its as-cast state.

[0100] 4. Place the alloy ingot melted in step 3 into the water-cooled copper crucible of a non-consumable vacuum arc furnace equipped with an ultrasonic device (i.e., install an ultrasonic amplitude rod below the water-cooled copper crucible of the non-consumable vacuum arc furnace) and close the furnace door. Simultaneously open the vacuum gauge, argon valve, and charging valve to charge the non-consumable vacuum arc furnace with inert argon gas for a total of 20 seconds. After charging is completed, close the argon valve and charging valve on the furnace body. Then, open the vacuum pump to evacuate the furnace body. When the vacuum count value drops to -2 MPa, close the vacuum gauge and vacuum pump. Begin melting the alloy ingot, controlling the melting current to slowly increase from 0A to 650A and maintain it at 650A for 40 seconds. Melt only once. During the final controlled current decrease, first reduce the current from 650A to 350A (decreasing by 50A every 10 seconds). When the current decreases to 350A, begin applying ultrasonic waves for 100 seconds. After the ultrasonic waves are applied, the current is slowly reduced to 0A, and the ultrasonic device is turned off. After the non-consumable vacuum arc furnace cools down, an ultrasonic Nb-16Si-20Zr-2C-2W alloy ingot is obtained.

[0101] 5. The prepared ultrasonic Nb-16Si-20Zr-2C-2W alloy ingot was placed into an alumina crucible and completely submerged in quartz sand using the sand-burying method, ensuring the quartz sand filled to half the crucible volume. Two pieces of titanium sponge were then placed on top of the submerged quartz sand, and quartz sand was continued to be added until the entire alumina crucible was filled. The heating program was entered into the heat treatment furnace and heating began. When the temperature in the heat treatment furnace reached 1300℃, the alumina crucible was placed on refractory bricks, and the refractory bricks, along with the alumina crucible, were placed into the heat treatment furnace. The furnace was maintained at 1300℃ for 30 hours. Afterward, the heating switch was turned off, allowing the alloy ingot to cool with the furnace. The alloy ingot was then removed from the crucible, yielding the heat-treated Nb-16Si-20Zr-2C-2W alloy. The purpose of placing two pieces of titanium sponge is that, in the high-temperature environment of the heat treatment furnace, the titanium sponge can further absorb oxygen and slow down the oxidation of the Nb-Si high-temperature alloy ingot in the alumina crucible.

[0102] 6. Use 400# SiC wet sandpaper to polish away the surface oxide scale of the heat-treated Nb-16Si-20Zr-2C-2W alloy, and the final preparation is completed.

[0103] The microstructure diagrams of the Nb-Si-Zr-C-xW high-temperature materials prepared in Examples 1 to 4 are shown below. Figure 1-4As shown, the microstructures of the five Nb-Si alloys prepared in Examples 1-4 all exhibit a niobium-based solid solution phase (Nbss phase) and a silicide phase (γ(Nb,X)5Si3 phase). The Nbss phase is a light gray phase, while the γ(Nb,X)5Si3 phase is a black phase, where X represents the alloying element that replaces Nb. The microstructure of the ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot prepared in Comparative Example 1 is shown in the figure. Figure 5 As shown, the ultrasonic waves did not completely destroy the microstructure. There are still large primary γ(Nb,X)5Si3 phases in the structure, and the edges of the primary γ(Nb,X)5Si3 phases are relatively sharp and have a cutting effect on the matrix.

[0104] Figure 1 The Nb-16Si-20Zr-2C-0.1W alloy prepared by ultrasonication and heat treatment contains many elongated or multi-elongated primary γ(Nb,X)5Si3 phases in its microstructure. These elongated γ(Nb,X)5Si3 phases have different orientations, and those with the same orientation are arranged periodically in the Nb-16Si-20Zr-2C-0.1W alloy. This is because ultrasonic waves were applied during the melting of the Nb-16Si-20Zr-2C-0.1W alloy in Example 1. During the solidification process, under the action of ultrasonic waves, the nucleation nuclei are periodically distributed in the alloy microstructure, and as the solidification process continues, the nucleation nuclei grow larger. The formation of elongated primary γ(Nb,X)5Si3 phases is primarily due to the fact that the microstructure after ultrasonic solidification consists mainly of large, blocky primary γ(Nb,X)5Si3 phases. However, after heat treatment, numerous fine Nbss / γ(Nb,X)5Si3 eutectoid structures grow within these larger blocky primary γ(Nb,X)5Si3 phases. The central portion of the larger blocky primary γ(Nb,X)5Si3 phases is replaced by eutectoid structures, ultimately forming periodically arranged elongated γ(Nb,X)5Si3 phases. This microstructure induces crack propagation and increases the alloy's toughness. This represents the beneficial effect of high-temperature heat treatment following ultrasonic-assisted solidification of Nb-Si superalloys on the high-temperature alloy material.

[0105] Figure 2The Nb-16Si-20Zr-2C-0.5W alloy shows a decrease in the size and quantity of the primary γ(Nb,X)5Si3 phase. The γ(Nb,X)5Si3 phase, as a hard and brittle phase in Nb-Si composites, is detrimental to the alloy's room-temperature fracture toughness. The decrease in the size and quantity of the primary γ(Nb,X)5Si3 phase in this alloy may be related to the increased W content. Increasing the W content and performing high-temperature heat treatment can promote an increase in the Nbss phase content and a decrease in the primary γ(Nb,X)5Si3 phase content in the alloy's microstructure. Furthermore, even after heat treatment, an Nbss / γ(Nb,X)5Si3 eutectoid structure still grows within the primary γ(Nb,X)5Si3 phase in the Nb-16Si-20Zr-2C-0.5W alloy.

[0106] Figure 3 and Figure 4 The images show the microstructures of the Nb-16Si-20Zr-2C-1W and Nb-16Si-20Zr-2C-2W alloys, respectively. The images reveal that after the combined ultrasonic and heat treatment, the primary γ(Nb,X)5Si3 phase in both alloys has completely disappeared, and the microstructure has become finer, mainly consisting of fine Nbss / γ(Nb,X)5Si3 eutectoid structures and some coarse Nbss / γ(Nb,X)5Si3 eutectoid structures. This microstructure refinement enhances the mechanical properties of the alloys.

[0107] The room temperature fracture toughness of the Nb-Si-Zr-C-xW high-temperature materials prepared in Examples 1 to 4 and the comparative examples is as follows: Figure 6 As shown, HT represents the heat treatment operation. It can be seen that due to the large amount of primary γ(Nb,X)5Si3 brittle phase in the microstructure of the material prepared in Comparative Example 1, and the regular polygonal shape of the primary γ(Nb,X)5Si3 brittle phase with sharp edges, it has a strong cutting effect on the matrix. Under this effect, the alloy exhibits very low room temperature fracture toughness, only 11.03 MPa·m. 1 / 2 .

[0108] The room temperature fracture toughness of the Nb-16Si-20Zr-2C-0.5W high-temperature material prepared in Example 2 is 11.8 MPa·m. 1 / 2 The alloy exhibits the lowest room-temperature fracture toughness, which is related to the retention of incomplete primary γ(Nb,X)5Si3 phase in its microstructure. The room-temperature fracture toughness of the Nb-16Si-20Zr-2C-1W high-temperature material prepared in Example 3 is 12.74 MPa·m. 1 / 2The improved fracture toughness of this alloy is related to the fact that after ultrasonic-assisted solidification and high-temperature heat treatment, the microstructure of the alloy has almost no hard and brittle primary γ(Nb,X)5Si3 phase, but contains more fine Nbss / γ(Nb,X)5Si3 eutectoid structures. This is attributed to the beneficial effect of high-temperature heat treatment after ultrasonic-assisted solidification on high-temperature materials. The room-temperature fracture toughness of the Nb-16Si-20Zr-2C-2W high-temperature material prepared in Example 4 is 13.51 MPa·m. 1 / 2 The improved fracture toughness of this alloy is related to the fact that the fine eutectoid Nbss / γ(Nb,X)5Si3 microstructure and the coarse eutectoid Nbss / γ(Nb,X)5Si3 microstructure have become finer. The room temperature fracture toughness of the Nb-16Si-20Zr-2C-0.1W high-temperature material prepared in Example 1 is 15.56 MPa·m. 1 / 2 The alloy exhibits the highest room-temperature fracture toughness, which is attributed to the residual elongated primary γ(Nb,X)5Si3 phases with different orientations remaining in the microstructure after the combined effects of ultrasonic treatment and heat treatment. This induces crack propagation because cracks are more likely to propagate in the hard and brittle γ(Nb,X)5Si3 phase, thus enhancing the alloy's toughness.

[0109] It can be seen that the method of combining ultrasonic-assisted solidification with high-temperature heat treatment of Nb-Si superalloys in this invention can significantly change the microstructure morphology of the alloy and induce crack propagation during the failure crack propagation process, thereby improving the toughness of the alloy. Although the process used in Examples 1-4 is the same, the alloy composition of each example is different. A small amount of W element will produce a large number of periodically arranged primary silicide phases in the alloy microstructure. After high-temperature heat treatment, these primary silicide phases will become periodically arranged elongated silicide phases. These silicide phases have a strong inducing effect on cracks, so they will greatly improve the toughness of the alloy. However, as the W element content increases, there are not a large number of primary silicide phases in the ultrasonic microstructure. However, after high-temperature heat treatment, the Nbss phase content will increase while the silicide phase content will decrease, and the phase edges will become more rounded, reducing the cutting effect of sharp boundaries on the Nb-Si superalloy matrix and stress concentration, thereby slightly improving the toughness of the Nb-Si superalloy.

Claims

1. A method for producing a high-temperature material having high toughness, characterized by, The method includes the following steps: I. Weigh the raw materials Nb, Si, Zr, C, and W according to the atomic percentage of elements in the Nb-16Si-20Zr-2C-0.1W alloy; 2. The surface of the raw materials is pretreated and placed into a crucible in a non-consumable vacuum arc furnace. At the same time, sponge titanium is added to an adjacent crucible. After the non-consumable vacuum arc furnace is evacuated, inert gas is introduced for melting. After cooling, a cast Nb-16Si-20Zr-2C-0.1W alloy ingot is obtained.

3. Place the alloy ingot obtained in step 2 into a water-cooled copper crucible in a non-consumable vacuum arc furnace equipped with an ultrasonic device, close the furnace door, open the vacuum gauge, argon valve and charging valve, and charge argon into the non-consumable vacuum arc furnace. Then close the argon valve and charging valve, evacuate the furnace, and then start melting. Melt only once. Apply ultrasonic action during the process of reducing the melting current. Then reduce the current to 0 A and then turn off the ultrasonic. After cooling, obtain an ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot. Fourth, first lay a layer of quartz sand at the bottom of the alumina crucible, then put in the ultrasonic Nb-16Si-20Zr-2C-0.1W alloy ingot obtained in step three, and then completely bury the alloy ingot with quartz sand. At this time, the quartz sand fills part of the alumina crucible. Then place sponge titanium on the quartz sand and continue to fill the quartz sand until the entire alumina crucible is filled. Heat the heat treatment furnace until the temperature reaches 1200~1400 ℃, place the alumina crucible on the refractory bricks, and put the refractory bricks together with the alumina crucible into the heat treatment furnace. Maintain the temperature at 1200~1400 ℃ for 30 hours, then turn off the heating and cool with the furnace to obtain the heat-treated Nb-16Si-20Zr-2C-0.1W alloy.

5. Remove the oxide scale from the surface of the heat-treated Nb-16Si-20Zr-2C-0.1W alloy by sanding with sandpaper, and the preparation is complete.

2. The method for preparing a high-toughness high-temperature material according to claim 1, characterized in that, The purity of the raw materials used in step one is all above 99.95%.

3. A method for preparing a high-toughness high-temperature material according to claim 1 or 2, characterized in that, The method for pre-treating the surface of the raw materials in step two is as follows: the surface of the raw materials is sanded with sandpaper, and the raw materials are placed in an ethanol solution for the first ultrasonic cleaning. After the first cleaning, the raw materials are placed in deionized water for the second ultrasonic cleaning. Then, the raw materials are dried with hot air.

4. The method of claim 1, wherein the high-temperature material having high toughness is prepared by the steps of: preparing a mixture of a high-temperature material and a binder; and sintering the mixture. In step two, the pretreated raw materials are placed into the crucible inside the non-consumable vacuum arc furnace in the order of W, C, Si, Zr, and Nb from bottom to top.

5. The method of claim 1, wherein the high-temperature material having high toughness is prepared by the steps of: preparing a mixture of a high-temperature material and a binder; and sintering the mixture. The melting process described in step two involves increasing the current to 650A and maintaining it at 650A for 30-40 seconds.

6. The method of claim 5, wherein the high-temperature material having high toughness is prepared by the steps of: preparing a mixture of a high-temperature material and a binder; and sintering the mixture. After melting once in step two, the alloy ingot is flipped 180° and melted again. This melting process is repeated 5 times.

7. The method for preparing a high-toughness high-temperature material according to claim 1, characterized in that, In step three, the melting process involves increasing the current to 650A and maintaining it at 650A for 30-40 seconds.

8. The method for preparing a high-temperature material with high toughness according to claim 7, characterized in that, Step 3: When the melting current is reduced from 650 A to 350 A, ultrasonic waves are applied for 100 s.

9. A method for preparing a high-toughness high-temperature material according to claim 1 or 8, characterized in that, The speed of reduction of the smelting current in step three is 50 A per 10 s.

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