A rare earth samarium toughened nb-si based ultrahigh temperature alloy and a preparation method thereof

Abstract

The application relates to a rare earth samarium toughened Nb-Si-based ultrahigh-temperature alloy and a preparation method thereof. The application aims to improve the room temperature toughness of the Nb-Si-based ultrahigh-temperature alloy without reducing the silicide phase content. The rare earth samarium toughened Nb-Si-based ultrahigh-temperature alloy is composed of Nb, Si, Ti, Al and Sm elements, and the expression is Nb-Ti-Si-Al-Sm. The alloy is prepared by vacuum arc furnace melting. The obtained rare earth Sm-added Nb-Si-based ultrahigh-temperature alloy is effectively toughened by improving the alloy phase composition and reducing the Si element pollution in the Nbss phase without reducing the silicide phase content. The application is applied to the field of high-temperature alloys.

Description

Technical Field

[0001] This invention relates to a rare earth samarium-toughened Nb-Si-based ultra-high temperature alloy and its preparation method. Background Technology

[0002] Increasing the turbine inlet temperature is crucial for improving the thrust-to-weight ratio of aircraft. The turbine inlet temperature of sixth-generation fighter jet engines is expected to reach 2400K, posing a significant challenge to turbine blade materials. Even with state-of-the-art cooling systems and thermal insulation coatings, the inherent temperature resistance of next-generation blade materials still needs to reach 1600-1700K. This temperature is approaching the melting point (1726K) of second-generation nickel-based single-crystal superalloys currently used in aircraft engine turbine blades. Nb-Si-based superalloys, with their extremely high high-temperature strength and low density, are considered the most likely next-generation superalloy for successful application. However, their relatively low room-temperature fracture toughness still hinders their processing and assembly in practical applications.

[0003] In Nb-Si-based superalloys, the silicide phase supports their high-temperature strength and oxidation resistance, while Nbss (Nb-based solid solution phase) is responsible for toughness, plasticity, and environmental stability. Studies have shown that the fracture toughness of the Nbss phase depends on the synergistic effect of Si with other alloying elements such as Al, Cr, Hf, and Ti. Specifically, the solid solution of Si in the Nbss phase has a highly detrimental effect on its fracture toughness; reducing the Si content in the Nbss phase can significantly improve the fracture toughness of the alloy. On the other hand, the interaction between the silicide and Nbss phases, such as their relative content, distribution, and morphology, also significantly influences the fracture toughness and high-temperature strength of the alloy. Therefore, it is necessary to develop a novel Nb-Si-based superalloy system that, without reducing the silicide phase content (i.e., without affecting the alloy's high-temperature performance), improves the alloy's fracture toughness by combining the reduction of elemental contamination in the Nbss phase with other alloying elements. Summary of the Invention

[0004] The purpose of this invention is to improve the room temperature toughness of Nb-Si-based superalloys without reducing the silicide phase content, and to provide a rare earth samarium-toughened Nb-Si-based superalloy and its preparation method.

[0005] The present invention discloses a rare earth samarium-toughened Nb-Si-based ultra-high temperature alloy, which is composed of 20-28% Ti, 14-18% Si, 2-5% Al, 0.05-0.4% Sm and the balance Nb by atomic percentage.

[0006] The present invention discloses a method for preparing a rare earth samarium-toughened Nb-Si-based superalloy, which is carried out according to the following steps: 1. Weighing Ti, Si, Al, Sm and Nb according to the proportion of 20-28% Ti, 14-18% Si, 2-5% Al, 0.05-0.4% Sm and balance Nb to obtain raw materials; wherein the sum of the atomic percentages of each component is 100%;

[0007] 2. The raw materials are pretreated and then added to the crucible of the melting furnace in the order of Sm, Al, Si, Ti and Nb from bottom to top. The melting furnace is then evacuated and filled with argon gas for protective melting. After cooling, the sample is obtained.

[0008] 3. The sample was repeatedly melted 6-8 times and cooled to obtain rare earth samarium toughened Nb-Si-based ultra-high temperature alloy.

[0009] The present invention has the following beneficial effects:

[0010] I. This invention incorporates high-melting-point Sm element. Sm element segregates at the solidification interface front, leading to compositional supercooling and altering the solidification path of the alloy, resulting in an increase in the γ-Nb5Si3 phase content and a decrease in the Nb5Si3 phase content. The addition of Sm element to the Nb-Si-based superalloy does not reduce the silicide phase content; instead, it facilitates the transformation of some Nb3Si phases into the γ-Nb5Si3 phase. The Nb3Si phase is metastable and exhibits strong intrinsic brittleness; the transformation from Nb3Si to γ-Nb5Si3 is highly beneficial to the alloy's room-temperature fracture resistance.

[0011] Second, the Si content in the Nbss phase was reduced, thus purifying the Nbss phase and improving the alloy microstructure, resulting in a significant refinement of the Nbss / Nb5Si3 eutectic microstructure. This achieved the goal of improving the room-temperature fracture toughness of Nb-Si-based superalloys without reducing the silicide phase content.

[0012] Third, this invention improves the room temperature fracture toughness of Nb-Si-based superalloys while enhancing their strength. Furthermore, subsequent directional solidification treatment can further improve their overall performance, making it a promising Nb-Si-based superalloy.

[0013] Fourth, the preparation process of this invention uses a vacuum electric arc furnace, which requires low equipment, has a simple process, is inexpensive, and has strong repeatability. Attached Figure Description

[0014] Figure 1 The X-ray diffraction patterns of Comparative Example 1 and Examples 2 and 3 are shown.

[0015] Figure 2 The microstructure of Comparative Example 1 and Examples 2 to 4;

[0016] Figure 3 These are crack propagation diagrams for Examples 2 and 3;

[0017] Figure 4 To compare the room temperature fracture toughness K of Example 1 and Examples 1 to 4 Q value. Detailed Implementation

[0018] 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.

[0019] Specific Implementation Method 1: In this implementation method, a rare earth samarium-toughened Nb-Si-based ultra-high temperature alloy is composed of 20-28% Ti, 14-18% Si, 2-5% Al, 0.05-0.4% Sm and the balance Nb by atomic percentage.

[0020] This embodiment applies rare earth samarium toughened Nb-Si-based ultra-high temperature alloys to the aerospace field.

[0021] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the alloy is composed of 24% Ti, 16% Si, 2% Al, 0.05% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-24Ti-16Si-2Al-0.05Sm. Everything else is the same as in Specific Implementation Method One.

[0022] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the alloy is composed of 28% Ti, 16% Si, 4% Al, 0.1% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-28Ti-16Si-4Al-0.1Sm. Everything else is the same as in Specific Implementation Method One or Two.

[0023] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the alloy is composed of 24% Ti, 15% Si, 2% Al, 0.2% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-24Ti-15Si-2Al-0.2Sm. Everything else is the same as in Specific Implementation Methods One to Three.

[0024] Specific Embodiment Five: This embodiment differs from Specific Embodiments One to Four in that the alloy is composed of 28% Ti, 15% Si, 4% Al, 0.4% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-28Ti-15Si-4Al-0.4Sm. Everything else is the same as in Specific Embodiments One to Four.

[0025] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the alloy is composed of 26% Ti, 16% Si, 2% Al, 0.1% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-26Ti-16Si-2Al-0.1Sm. Everything else is the same as in Specific Implementation Methods One to Five.

[0026] Specific Embodiment Seven: This embodiment differs from Specific Embodiments One to Six in that the alloy is composed of 26% Ti, 14% Si, 2% Al, 0.2% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-26Ti-14Si-2Al-0.2Sm. Everything else is the same as in Specific Embodiments One to Six.

[0027] Specific Embodiment Eight: This embodiment differs from Specific Embodiments One to Seven in that the alloy is composed of 24% Ti, 14% Si, 4% Al, 0.4% Sm, and the balance Nb by atomic percentage, with the chemical formula Nb-24Ti-14Si-4Al-0.4Sm. Everything else is the same as in Specific Embodiments One to Seven.

[0028] Specific Implementation Method Nine: The preparation method of a rare earth samarium-toughened Nb-Si-based superalloy in this implementation method is carried out according to the following steps: 1. Weigh Ti, Si, Al, Sm and Nb according to the proportion of 20-28% Ti, 14-18% Si, 2-5% Al, 0.05-0.4% Sm and balance Nb to obtain raw materials; wherein the sum of the atomic percentages of each component is 100%;

[0029] 2. The raw materials are pretreated and then added to the crucible of the melting furnace in the order of Sm, Al, Si, Ti and Nb from bottom to top. Then, sponge titanium is added to another crucible in the melting furnace. The melting furnace is then evacuated and filled with argon gas for protective melting. After cooling, the sample is obtained.

[0030] 3. The sample was repeatedly melted 6-8 times and cooled to obtain rare earth samarium toughened Nb-Si-based ultra-high temperature alloy.

[0031] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that the raw material pretreatment method is as follows: after removing the oxide scale, the raw material is ultrasonically cleaned with anhydrous alcohol at a power of 100-120W and a cleaning frequency of 20-25KHz. Everything else is the same as in Specific Implementation Method Nine.

[0032] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Methods Nine or Ten in that the smelting furnace is evacuated to a vacuum level of 3×10. -4Pa, then argon gas is introduced to below 0.8 MPa. Everything else is the same as in specific embodiment nine or ten.

[0033] Specific Implementation Method Twelve: This implementation method differs from Specific Implementation Methods Nine to Eleven in that: in step three, a vacuum non-consumable arc furnace is used for melting. The melting temperature is controlled by the current intensity, which is 50-650A. When the melt is completely melted, the current is held at 600-650A for 1-2 minutes. Then, the current intensity decreases at a rate of 50-100A every 5 seconds. Finally, the alloy cools and solidifies with the furnace, yielding a rare earth samarium-toughened Nb-Si-based ultra-high temperature alloy. Everything else is the same as in Specific Implementation Methods Nine to Eleven.

[0034] The beneficial effects of the present invention are verified using the following embodiments:

[0035] Example 1: A rare-earth samarium-toughened Nb-Si-based superalloy is composed of Nb, Ti, Si, Al, and Sm elements, with the formula Nb-24Ti-16Si-2Al-0.05Sm, where Ti content is 24 at.%, Si content is 16 at.%, Al content is 2 at.%, Sm content is 0.05 at.%, and the balance is Nb. Its preparation method is as follows:

[0036] Step 1: Weigh out the elemental Nb, Ti, Si, Al, and Sm according to atomic percentage, wherein the elemental Nb, Ti, Si, and Al are all 99.95% pure and have a size of [missing information]. The columnar particles, with Sm elemental purity of 99.50% and a size of 1-15 mm, were used. After removing the oxide scale of Nb, Ti, Si, Al, and Sm elemental substances, they were ultrasonically cleaned with anhydrous alcohol at a power of 100 W and a cleaning frequency of 20 kHz.

[0037] Step 2: Place the elements Sm, Al, Si, Nb, and Ti into the melting furnace crucible in that order. Wrap the elemental Sm in aluminum foil to prevent it from being blown away during the melting process. Add sponge titanium to another crucible.

[0038] Step 3: Divide the smelting furnace into 3×10 sections. -4 After establishing a vacuum below 0.8 MPa, high-purity argon gas was added to a pressure below 0.8 MPa to maintain the melting process in an argon atmosphere. First, sponge titanium was melted to remove residual oxygen from the furnace, followed by the melting of the raw materials. When the raw material melt was completely melted, the current was maintained at 600 A for 2 minutes, then decreased at a rate of 100 A every 5 seconds, and finally the alloy solidified with the furnace cooling. To ensure alloy homogeneity, the raw materials were repeatedly melted 6 times, and after cooling, a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy was obtained.

[0039] Example 2: A rare-earth samarium-toughened Nb-Si-based superalloy is composed of Nb, Ti, Si, Al, and Sm elements, with the formula Nb-26Ti-16Si-2Al-0.1Sm, where Ti content is 26 at.%, Si content is 16 at.%, Al content is 2 at.%, Sm content is 0.1 at.%, and the balance is Nb. Its preparation method is as follows:

[0040] Step 1: Weigh out the elemental Nb, Ti, Si, Al, and Sm according to atomic percentage, wherein the elemental Nb, Ti, Si, and Al are all 99.95% pure and have a size of [missing information]. The columnar particles, with elemental Sm having a purity of 99.50% and a size of 1-15 mm, were used. After removing the oxide scale from elemental Nb, Ti, Si, Al, and Sm, they were ultrasonically cleaned with anhydrous ethanol at a power of 120 W and a cleaning frequency of 25 kHz.

[0041] Step 2: Place the elements Sm, Al, Si, Nb, and Ti into the melting furnace crucible in that order. Wrap the elemental Sm in aluminum foil to prevent it from being blown away during the melting process. Add sponge titanium to another crucible.

[0042] Step 3: Divide the smelting furnace into 3×10 sections. -4 After establishing a vacuum below 0.5 MPa, high-purity argon gas was added to a pressure below 0.6 MPa to maintain the melting process in an argon atmosphere. First, sponge titanium was melted to remove residual oxygen from the furnace, followed by the melting of the raw materials. When the raw material melt was completely melted, the current was maintained at 650 A for 2 minutes, then decreased at a rate of 100 A every 5 seconds, and finally the alloy solidified with the furnace cooling. To ensure alloy homogeneity, the raw materials were repeatedly melted 6 times, and after cooling, a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy was obtained.

[0043] Example 3: A rare-earth samarium-toughened Nb-Si-based superalloy is composed of Nb, Ti, Si, Al, and Sm elements, with the formula Nb-26Ti-14Si-2Al-0.2Sm, where Ti content is 26 at.%, Si content is 14 at.%, Al content is 2 at.%, Sm content is 0.2 at.%, and the balance is Nb. Its preparation method is as follows:

[0044] Step 1: Weigh out the elemental Nb, Ti, Si, Al, and Sm according to atomic percentage, wherein the elemental Nb, Ti, Si, and Al are all 99.95% pure and have a size of [missing information]. The columnar particles, with elemental Sm having a purity of 99.50% and a size of 1-15 mm, were used. After removing the oxide scale from elemental Nb, Ti, Si, Al, and Sm, they were ultrasonically cleaned with anhydrous ethanol at a power of 120 W and a cleaning frequency of 25 kHz.

[0045] Step 2: Place the elements Sm, Al, Si, Nb, and Ti into the melting furnace crucible in that order. Wrap the elemental Sm in aluminum foil to prevent it from being blown away during the melting process. Add sponge titanium to another crucible.

[0046] Step 3: Divide the smelting furnace into 3×10 sections. -4 After establishing a vacuum below 0.5 MPa, high-purity argon gas was added to a pressure below 0.6 MPa to maintain the melting process in an argon atmosphere. First, sponge titanium was melted to remove residual oxygen from the furnace, followed by the melting of the raw materials. When the raw material melt was completely melted, the current was maintained at 600 A for 1 minute, then decreased at a rate of 50 A every 5 seconds, and finally the alloy solidified with the furnace cooling. To ensure alloy homogeneity, the raw materials were repeatedly melted 8 times, and after cooling, a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy was obtained.

[0047] Example 4: A rare-earth samarium-toughened Nb-Si-based superalloy is composed of Nb, Ti, Si, Al, and Sm elements, with the formula Nb-24Ti-14Si-4Al-0.4Sm, where Ti content is 24 at.%, Si content is 14 at.%, Al content is 4 at.%, Sm content is 0.4 at.%, and the balance is Nb. Its preparation method is as follows:

[0048] Step 1: Weigh out the elemental Nb, Ti, Si, Al, and Sm according to atomic percentage, wherein the elemental Nb, Ti, Si, and Al are all 99.95% pure and have a size of [missing information]. The columnar particles, with Sm elemental purity of 99.50% and a size of 1-15 mm, were used. After removing the oxide scale of Nb, Ti, Si, Al, and Sm elemental substances, they were ultrasonically cleaned with anhydrous alcohol at a power of 100 W and a cleaning frequency of 20 kHz.

[0049] Step 2: Place the elements Sm, Al, Si, Nb, and Ti into the melting furnace crucible in that order. Wrap the elemental Sm in aluminum foil to prevent it from being blown away during the melting process. Add sponge titanium to another crucible.

[0050] Step 3: Divide the smelting furnace into 3×10 sections. -4 After establishing a vacuum below 0.8 MPa, high-purity argon gas was added to a pressure below 0.8 MPa to maintain the melting process in an argon atmosphere. First, sponge titanium was melted to remove residual oxygen from the furnace, followed by the melting of the raw materials. When the raw material melt was completely melted, the current was maintained at 650 A for 2 minutes, then decreased at a rate of 50 A every 5 seconds. Finally, the alloy solidified with the furnace cooling. To ensure alloy homogeneity, the raw materials were repeatedly melted eight times, and after cooling, a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy was obtained.

[0051] Comparative Example 1: A Nb-Si based superalloy is composed of Nb, Ti, Si, and Al elements, with the formula Nb-26Ti-16Si-2Al. The Ti content is 26 at.%, the Si content is 16 at.%, the Al content is 2 at.%, and the balance is Nb. Its preparation method is as follows:

[0052] Step 1: Weigh out Nb, Ti, Si, and Al elements according to atomic percentage. All Nb, Ti, Si, and Al elements have a purity of 99.95% and a size of [missing information]. The columnar particles were removed. After removing the oxide scale of elemental Nb, Ti, Si, and Al, they were ultrasonically cleaned with anhydrous ethanol at a power of 120W and a cleaning frequency of 25KHz.

[0053] Step 2: Place Al, Si, Nb, and Ti into the melting furnace crucible in that order, and add sponge titanium to another crucible;

[0054] Step 3: Divide the smelting furnace into 3×10 sections. -4 After establishing a vacuum below 0.5 MPa, high-purity argon gas was added to a pressure below 0.6 MPa to maintain the melting process in an argon atmosphere. First, sponge titanium was melted to remove residual oxygen from the furnace, followed by the melting of the raw materials. When the raw material melt was completely melted, the current was maintained at 650 A for 2 minutes, then decreased at a rate of 100 A every 5 seconds. Finally, the alloy solidified with the furnace cooling. To ensure alloy homogeneity, the raw materials were repeatedly melted six times, and after cooling, an Nb-Si-based ultra-high temperature alloy was obtained.

[0055] The X-ray diffraction patterns of Comparative Example 1 and Examples 2 and 3 are as follows: Figure 1 As shown. Among them "●" represents the Nb5Si phase, "□" represents the Nb3Si phase, and "□" represents the γ-Nb5Si3 phase. The phase composition of Comparative Example 1 is the same as that of Examples 2 and 3, meaning that the addition of Sm to the Nb-Si-based superalloy does not change the phase composition of the alloy. However, the Nb3Si phase diffraction peak at 33° in Comparative Example 1 disappears in Examples 2 and 3, and the number of γ-Nb5Si3 phase diffraction peaks increases in Examples 2 and 3. This is because the high-melting-point Sm element segregates at the solidification interface front, leading to compositional supercooling, which alters the solidification path of the alloy, increasing the γ-Nb5Si3 phase content and decreasing the Nb5Si3 phase content. The addition of Sm to the Nb-Si-based superalloy does not reduce the silicide phase content, but rather achieves a partial transformation of the Nb3Si phase to the γ-Nb5Si3 phase. The Nb3Si phase is a metastable phase with strong intrinsic brittleness. The transformation of the Nb3Si phase to the γ-Nb5Si3 phase is very beneficial to the room temperature fracture resistance of the alloy.

[0056] The microstructures of Comparative Example 1 and Examples 2 to 4 are as follows Figure 2 As shown, the compositional supercooling caused by Sm element affects the solidification path of the alloy, resulting in a significantly refined alloy microstructure. This increases the plastic work that needs to be overcome during fracture, which is also beneficial to the room temperature fracture toughness of the alloy. The area percentage of silicides obtained by software calculation of the microstructure is shown in Table 1. As can be seen from Table 1, the addition of Sm element to Nb-Si based superalloys did not reduce the silicide phase content.

[0057] Table 1

[0058]

[0059]

[0060] Crack propagation diagrams for Examples 2 and 3 are shown below. Figure 3 As shown, distinct slip bands appeared in the Nbss phase. Slip bands are a typical characteristic of plastic deformation in metallic materials and can only be observed in relatively pure materials. Energy dispersive spectroscopy (EDS) results showed that the average Si content in the Nbss phase in Comparative Example 1 was 3.05 at.%, while the average Si content in the Nbss phase in Example 2 was 1.36 at.%, and the average Si content in the Nbss phase in Example 3 was 1.12 at.%. The addition of Sm element reduced the Si content, purified the Nbss phase, improved the deformability of the Nbss phase, and thus enhanced the toughness of the Nb-Si based superalloy.

[0061] Room temperature fracture toughness K of Comparative Example 1 and Examples 1 to 4 Q Values ​​such as Figure 4 As shown, the addition of rare earth element Sm significantly improves the room temperature fracture toughness of Nb-Si based superalloys. Comparative Example 1 alloy's K... Q The value is 13.25 MPa·m 1 / 2 Example 1, K of alloy Q The value is 15.64 MPa·m 1 / 2 Example 2 alloy K Q The value is 17.73 MPa·m 1 / 2 Example 3, K of alloy Q The value is 18.15 MPa·m 1 / 2 Example 4, K alloy Q The value is 18.23 MPa·m 1 / 2 Example 4: K of the alloy Q The value increased by 37.6% compared to the control group.

Claims

1. A rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy, characterized in that, The alloy has the chemical formulas Nb-24Ti-16Si-2Al-0.05Sm, Nb-28Ti-16Si-4Al-0.1Sm, Nb-24Ti-15Si-2Al-0.2Sm, Nb-28Ti-15Si-4Al-0.4Sm, Nb-26Ti-16Si-2Al-0.1Sm, Nb-26Ti-14Si-2Al-0.2Sm, or Nb-24Ti-14Si-4Al-0.4Sm. The Nb-24Ti-16Si-2Al-0.05Sm alloy consists of 24% Ti, 16% Si, 2% Al, 0.05% Sm, and the balance Nb by atomic percentage; the Nb-28Ti-16Si-4Al-0.1Sm alloy consists of 28% Ti, 16% Si, 4% Al, 0.1% Sm, and the balance Nb by atomic percentage; the Nb-24Ti-15Si-2Al-0.2Sm alloy consists of 24% Ti, 15% Si, 2% Al, 0.2% Sm, and the balance Nb by atomic percentage; and the Nb-28Ti-15Si-4Al-0.4Sm alloy consists of 28% Ti, 15% Si, 4% Al, and the balance Nb by atomic percentage. The Nb-Si based superalloys are composed of 0.4% Sm and the balance Nb; Nb-26Ti-16Si-2Al-0.1Sm is composed of 26% Ti, 16% Si, 2% Al, 0.1% Sm and the balance Nb by atomic percentage; Nb-26Ti-14Si-2Al-0.2Sm is composed of 26% Ti, 14% Si, 2% Al, 0.2% Sm and the balance Nb by atomic percentage; Nb-24Ti-14Si-4Al-0.4Sm is composed of 24% Ti, 14% Si, 4% Al, 0.4% Sm and the balance Nb by atomic percentage; the Nb-Si based superalloys contain Nbss phase, Nb3Si phase and γ-Nb5Si3 phase.

2. The method for preparing a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy as described in claim 1, characterized in that, The preparation method is carried out according to the following steps:

1. Weigh Ti, Si, Al, Sm and Nb in proportion to obtain raw materials; 2. The raw materials are pretreated and then added to the crucible of the melting furnace in the order of Sm, Al, Si, Ti and Nb from bottom to top. Then, sponge titanium is added to another crucible in the melting furnace. The melting furnace is then evacuated and filled with argon gas for protective melting. After cooling, the sample is obtained.

3. The sample was repeatedly melted 6-8 times and cooled to obtain rare earth samarium toughened Nb-Si-based ultra-high temperature alloy.

3. The method for preparing a rare-earth samarium-toughened Nb-Si-based ultra-high temperature alloy according to claim 2, characterized in that, The smelting furnace was evacuated to 3×10 -4 Pa, then fill with argon gas to below 0.8 MPa.

Images