A tantalum-based alloy and a method for producing the same

Abstract

The application provides a tantalum-based alloy and a preparation method thereof. The preparation method of the tantalum-based alloy comprises the following steps: sequentially laying a first mixed material, a second mixed material and magnesium chips in a reaction crucible in a top-down direction, igniting the reaction crucible to generate an aluminothermic reduction reaction, and then sequentially performing a temperature reduction treatment and a surface finishing treatment to obtain the tantalum-based alloy. The first mixed material comprises aluminum particles, tantalum pentoxide, titanium oxide, potassium chlorate and aluminum fluoride. The second mixed material comprises aluminum particles, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride and calcium fluoride. By adopting double dosing and covering the magnesium chips with the upper material, the application improves the ignition efficiency, significantly improves the material loss caused by the slow ignition speed and insufficient ignition of the material in the traditional off-oven method, and introduces a titanium source to form an AlTaTi compound, thereby significantly enhancing the alloy uniformity.

Description

Technical Field

[0001] This invention belongs to the field of metal material preparation technology, and relates to a tantalum-based alloy, specifically a tantalum-based alloy and its preparation method. Background Technology

[0002] As the core power unit in the aerospace field, the performance of aerospace engines directly determines the flight speed, range, and payload capacity of aircraft. Material properties are one of the key factors restricting the upgrading and iteration of aerospace engines. High-temperature titanium alloys, with their high specific strength, excellent creep resistance, and outstanding high-temperature resistance, exhibit irreplaceable advantages in reducing engine structural weight and improving thrust-to-weight ratio. They have become the preferred material for manufacturing core load-bearing components such as compressor disks, blades, and casings of aerospace engines. Their quality directly affects the reliability, safety, and service life of aerospace equipment, and is of significant strategic importance to the development of the defense industry and the aerospace sector.

[0003] In the smelting process of high-temperature titanium alloys, aluminum-tantalum-titanium alloys are indispensable key additives. The introduction of tantalum can significantly improve the high-temperature strength, creep resistance, and corrosion resistance of titanium alloys. Titanium, as the matrix element of high-temperature titanium alloys, can further optimize the alloy composition matching and reduce the compositional fluctuations of the matrix elements during smelting by pre-pre-existing in the master alloy. Aluminum plays a crucial role in regulating the alloy's melting point and improving melt fluidity. Tantalum itself has an extremely high melting point; if directly added to the titanium alloy melt, it is difficult to dissolve uniformly and easily forms high-density inclusions, severely affecting the alloy's mechanical and processing properties. Aluminum-tantalum-titanium master alloys, by pre-alloying tantalum, titanium, and aluminum, not only allow for more precise control of the ratio of the three elements and effectively reduce the actual melting temperature of tantalum, further improving the solubility and dispersion of tantalum in the titanium alloy melt, but also minimize the formation of high-density inclusions and compositional segregation, thus more reliably ensuring the smelting quality of high-temperature titanium alloys. Therefore, the quality of aluminum-tantalum-titanium master alloys directly determines the performance stability and high-end level of domestically produced high-temperature titanium alloys.

[0004] Currently, the industrial preparation of tantalum-containing master alloys mainly focuses on aluminum-tantalum binary alloys, with preparation methods including vacuum aluminothermic reduction and traditional ladle aluminothermic methods. However, when used to prepare aluminum-tantalum-titanium ternary alloys, the technical shortcomings are more prominent, making it difficult to meet the production requirements of high-quality high-temperature titanium alloys. While the vacuum aluminothermic reduction method can produce alloy products with low nitrogen impurity content, it requires complex equipment structures, involves cumbersome operating procedures, and incurs high equipment maintenance costs. Furthermore, the ternary alloy reaction system is more complex, with increased reaction intensity and a greater likelihood of splashing, leading to low production efficiency and significant challenges for large-scale industrial production. Although the traditional ladle aluminothermic method has the advantages of simple equipment and low initial investment, the reaction takes place in an open or semi-open environment, making it more difficult to control the compositional uniformity of the aluminum-tantalum-titanium ternary alloy. Gas-phase impurities such as oxygen and nitrogen are easily mixed in, and the burn-off rates of the three elements differ significantly, easily causing severe compositional segregation within the alloy ingot and deviations from the design element ratios. Ultimately, this results in low-quality alloy products that cannot meet the stringent requirements of high-end high-temperature titanium alloys for master alloy purity, compositional uniformity, and ratio accuracy.

[0005] With the rapid development of the aerospace industry, the demand for high-quality high-temperature titanium alloys is becoming increasingly urgent. However, the shortcomings of existing binary tantalum-containing master alloys and traditional preparation technologies have become a bottleneck restricting the quality upgrade of domestically produced high-temperature titanium alloys. In particular, they cannot meet the requirements of high-end titanium alloys for precise multi-element ratios and low impurity content, which not only affects the performance upgrade of aerospace equipment but also poses a potential risk to the security and integrity of the defense industry chain. Therefore, developing an aluminum-tantalum-titanium alloy and its preparation method with precise composition, excellent quality, stable preparation process, and suitability for industrial production, breaking through the limitations of existing technologies, improving the quality and performance stability of domestically produced high-temperature titanium alloys, and ensuring the security of the defense industry chain have become urgent technical problems to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a tantalum-based alloy and its preparation method. By employing a double-batch feeding method and covering the upper layer of material with magnesium shavings, the ignition efficiency is improved, significantly reducing material loss caused by slow ignition speed and incomplete combustion of materials in traditional furnace-outdoor methods. Furthermore, by introducing a titanium source to form an AlTaTi compound, the alloy uniformity is significantly enhanced.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a tantalum-based alloy, wherein, by mass fraction, the tantalum-based alloy comprises: 55-65 wt% tantalum, 6-15 wt% titanium, ≤0.05 wt% iron, ≤0.15 wt% silicon, ≤0.1 wt% oxygen, ≤0.02 wt% nitrogen, and the balance being aluminum.

[0008] For example, the tantalum content in the tantalum-based alloy is 55~65wt%, such as 55wt%, 57wt%, 59wt%, 61wt%, 63wt%, or 65wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. The titanium content is 6~15wt%, for example, it can be 6wt%, 8wt%, 10wt%, 12wt%, 14wt% or 15wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. The iron content is ≤0.05wt%, which can be, for example, 0.05wt%, 0.045wt%, 0.04wt%, 0.035wt%, 0.03wt%, 0.025wt%, or 0.02wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. The silicon content is ≤0.15wt%, for example, it can be 0.15wt%, 0.14wt%, 0.13wt%, 0.12wt%, 0.11wt%, or 0.10wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range also apply. The oxygen content is ≤0.1wt%, which can be, for example, 0.1wt%, 0.09wt%, 0.08wt%, 0.07wt%, 0.06wt%, or 0.05wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. The nitrogen content is ≤0.02wt%, for example, it can be 0.02wt%, 0.018wt%, 0.016wt%, 0.014wt%, 0.012wt%, or 0.01wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0009] This invention innovatively introduces titanium into tantalum-based alloys, forming intermetallic compounds and solid solutions in the tantalum-titanium alloys: the formed AlTaTi compound significantly enhances the alloy uniformity; in the solid solution, due to the high viscosity of titanium, it is dissolved together with aluminum and tantalum, reducing gravitational segregation during the cooling process and further improving the alloy uniformity.

[0010] As a preferred embodiment of the present invention, the thickness of the tantalum-based alloy is 5 to 10 cm, for example, it can be 5 cm, 6 cm, 7 cm, 8 cm, 9 cm or 10 cm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] When preparing tantalum-based alloys using the preparation method provided by this invention, the thickness of the tantalum-based alloy needs to be controlled to be 5-10 cm. The reason for this is to prevent gravity segregation that may occur due to excessive alloy ingot thickness, which would affect the uniformity of the alloy.

[0012] In a second aspect, the present invention provides a method for preparing a tantalum-based alloy as described in the first aspect, the method comprising the following steps: In a bottom-up direction, the first mixture, the second mixture, and magnesium shavings are sequentially laid in the reaction crucible. After ignition, an aluminothermic reduction reaction occurs, followed by cooling and surface finishing treatments to obtain the tantalum-based alloy. The first mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, and aluminum fluoride; The second mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride, and calcium fluoride.

[0013] In this invention, the grade of aluminum-tantalum-titanium alloy is controlled by controlling the feeding ratio of aluminum particles, tantalum pentoxide, titanium oxide, and potassium chlorate. More specifically, in the first mixture, the traditional slag-forming agent is calcium fluoride, which has a low melting point (approximately 1423°C). When mixed with alumina, it forms eutectic fluoroaluminate, significantly reducing the melting point of the slag system and improving the fluidity of the melt. In addition, to improve the fluidity of the alloy, a large amount of fluoride ions needs to be introduced. If calcium fluoride is used, it will lead to a significant reduction in the heat of the system, which is not conducive to slag and gas-liquid separation for high-melting-point alloys such as tantalum and tungsten. This invention uses aluminum fluoride instead of calcium fluoride (for equal weights of aluminum fluoride and calcium fluoride, the fluorine content of aluminum fluoride is 1.39 times that of calcium fluoride), which can significantly reduce the amount of slag-forming agent added, improve the unit furnace charge heat effect and total heat of the system, and facilitate the separation of alumina inclusions and gaseous impurities from the alloy exterior. The second mixture is laid under the magnesium shavings. After ignition, the reaction spreads to the first mixture. The second mixture uses a combination of aluminum fluoride and calcium fluoride. Compared with adding only calcium fluoride or aluminum fluoride, the thermal effect per unit charge is at an intermediate level. On the one hand, if all the slagging agents in the second mixture are calcium fluoride, the thermal effect per unit charge will be too low. Due to the different ignition points of magnesium strips, the horizontal reaction spread rate of the surface material of the second mixture is lower than that in the vertical direction. This results in the lower layer of material starting to react before the second mixture has completely reacted. The violent reaction will cause the unreacted raw materials in the upper layer to splash out of the molten pool along with some of the lower layer of material, resulting in material loss. Using aluminum fluoride and calcium fluoride as slagging agents can effectively balance the horizontal and vertical spread rates. On the other hand, if all the slagging agents are aluminum fluoride, the reaction heat will be too high. At the same time, the fluidity of the alumina-aluminum fluoride slag system is increased by the addition of aluminum fluoride, which easily leads to violent splashing at the beginning of the reaction, resulting in material loss and increased oxygen and nitrogen content, affecting the yield and alloy quality.

[0014] As a preferred embodiment of the present invention, the mass ratio of tantalum pentoxide in the first mixture and the second mixture is 7~9:1~3, for example, it can be 7:3, 8:2, 9:1, 7.5:2.5 or 8.5:1.5, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] This invention ensures that the overall unit furnace charge thermal effect is at a high level by controlling the mass ratio of tantalum pentoxide in the first mixture and the second mixture, which is beneficial to the homogenization of high melting point alloys. If the mass ratio is too low (the mass of tantalum pentoxide in the first mixture is too low), the overall heat will be reduced, which is not conducive to the separation of alloy slag and liquid. If the mass ratio is too high, it will lead to severe splashing and excessive material loss.

[0016] Preferably, the mass ratio of aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, and aluminum fluoride in the first mixture is (10~14):(11~16):(1~5):(4~7):(1~5), for example, it can be 10:11:1:4:1, 14:16:5:7:5, 12:13:3:5.5:3, 11:15:4:6:4, or 13:13:2:5:3, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the mass ratio of aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride, and calcium fluoride in the second mixture is (10~14):(11~16):(1~5):(4~7):(0.5~2):(1~2), for example, it can be 10:11:1:4:0.5:1, 14:16:5:7:2:2, 12:13:3:1.2:1.5, 11:15:4:6:0.8:1.8, or 13:13:2:5:1.8:1.2, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. As a preferred embodiment of the present invention, before laying the second mixture, the first mixture is further subjected to compaction treatment.

[0018] Preferably, the compaction pressure is 2.5~7MPa, for example, it can be 2.5MPa, 3MPa, 4MPa, 5MPa, 6MPa or 7MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the compaction time is 3 to 12 minutes, for example, it can be 3 minutes, 4 minutes, 6 minutes, 8 minutes, 10 minutes or 12 minutes, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] In this invention, because the heat and slag fluidity of the first mixture are at a high level during the reaction process, compaction can effectively reduce material splashing during the reaction, reduce raw material loss, and improve alloy quality. The second mixture is evenly spread on the upper surface of the first mixture, so there is no need for compaction. The reason is that the unit furnace charge heat effect of tantalum oxide is only 378 kcal / kg. In the process of preparing aluminum-tantalum alloy through redox reaction, the reaction heat is mainly provided by potassium chlorate (3353 kcal / kg). However, the activation energies of potassium chlorate and tantalum pentoxide are both around 250~320 kJ / mol, making the reaction difficult to ignite. The reason for not compacting the second mixture is to increase the oxygen concentration between materials and improve the ignition efficiency.

[0021] As a preferred embodiment of the present invention, the width of the magnesium shavings is 2 to 15 mm, for example, it can be 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm or 15 mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the length of the magnesium shavings is 10~20mm, for example, it can be 10mm, 12mm, 14mm, 16mm, 18mm or 20mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the thickness of the magnesium shavings is 0.1~1.5mm, for example, it can be 0.1mm, 0.3mm, 0.6mm, 0.9mm, 1.2mm or 1.5mm, but is not limited to the listed values. Other values ​​within the range that are not listed are also applicable.

[0024] Preferably, in each aluminothermic reduction reaction, the amount of magnesium shavings added is 100~300g, for example, 100g, 140g, 180g, 220g, 260g or 300g, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] In this invention, the magnesium shavings are uniformly spread on the upper surface of the second mixture. Compared to the conventional aluminothermic reaction, which typically releases more than 600 kcal / kg of heat, the aluminothermic reduction reaction of tantalum pentoxide releases only 378 kcal / kg, with a minimum heat release of 550 kcal / kg. Although potassium chlorate can provide heat for the reaction, it still needs to be ignited before it can release heat. This results in insufficient reaction of the tantalum-based alloy produced by the aluminothermic method (the vertical reaction rate is greater than the horizontal reaction rate after each strip is ignited, and slight splashing occurs after the lower material reacts, causing the unreacted material at the top to be ejected, leading to a significant reduction in yield). With the addition of magnesium shavings to the surface, the upper part is ignited by the magnesium strip, and the diffusion rate is greater than the vertical spread rate of the aluminothermic reaction, thus allowing the material to react fully and improving the first-pass yield of the alloy.

[0026] As a preferred embodiment of the present invention, the igniter used for ignition is a magnesium strip.

[0027] Preferably, the width of the magnesium strip is 10~30mm, for example, it can be 10mm, 14mm, 18mm, 22mm, 26mm or 30mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the length of the magnesium strip is 100~200mm, for example, it can be 100mm, 120mm, 140mm, 160mm, 180mm or 200mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the thickness of the magnesium strip is 0.1~1.5mm, for example, it can be 0.1mm, 0.3mm, 0.6mm, 0.9mm, 1.2mm or 1.5mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the amount of magnesium strip used is 150~250g, for example, it can be 150g, 170g, 190g, 210g, 230g or 250g, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0031] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) The tantalum-based alloy (aluminum-tantalum-titanium master alloy) provided by the present invention has excellent alloy uniformity, which can further improve the quality of domestic high-temperature titanium alloys and ensure the safety and integrity of the national defense industry chain. (2) The preparation method provided by the present invention solves the problems of slow ignition, large burn-off and serious segregation of alloy ingots in the production process of aluminum-tantalum-titanium alloy, and provides a high-quality aluminum-tantalum-titanium master alloy for domestic high-temperature titanium alloys. (3) By adopting a double batching method and covering the upper material with magnesium shavings, the present invention improves the ignition efficiency, significantly improves the material loss caused by the slow ignition speed and insufficient material ignition in the traditional furnace external method, and significantly enhances the alloy uniformity by introducing a titanium source to form an AlTaTi compound. Attached Figure Description

[0033] Figure 1 Metallographic image of the tantalum-based alloy provided in Embodiment 1 of the present invention; Figure 2 This is a scanning electron microscope image of a tantalum-based alloy provided in Embodiment 1 of the present invention; Figure 3 This is an elemental distribution diagram of the tantalum-based alloy provided in Embodiment 1 of the present invention; Figure 4 Metallographic image of the tantalum-based alloy provided in Comparative Example 1 of this invention; Figure 5 A scanning electron microscope image of the tantalum-based alloy provided in Comparative Example 1 of this invention; Figure 6 The elemental distribution diagram of the tantalum-based alloy provided in Comparative Example 1 of this invention; Figure 7 The above are sampling point distribution diagrams of the tantalum-based alloys described in Examples 3-12 and Comparative Examples 2-4 of this invention. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0035] In one specific embodiment, the present invention provides a tantalum-based alloy, which, by mass fraction, comprises: 55-65 wt% tantalum, 6-15 wt% titanium, ≤0.05 wt% iron, ≤0.15 wt% silicon, ≤0.1 wt% oxygen, ≤0.02 wt% nitrogen, with the balance being aluminum; The thickness of the tantalum-based alloy is 5~10cm.

[0036] In another specific embodiment, the present invention provides a method for preparing a tantalum-based alloy, the method comprising the following steps: In a bottom-up direction, the first mixture, the second mixture, and magnesium shavings are sequentially laid in the reaction crucible. After being ignited with magnesium strips as igniters, an aluminothermic reduction reaction occurs. Then, cooling treatment and surface finishing treatment are performed sequentially to obtain the tantalum-based alloy. The first mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, and aluminum fluoride in a mass ratio of (10~14):(11~16):(1~5):(4~7):(1~5); The second mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride and calcium fluoride in a mass ratio of (10~14):(11~16):(1~5):(4~7):(0.5~2):(1~2); The mass ratio of tantalum pentoxide in the first mixture and the second mixture is 7~9:1~3; Before laying the second mixture, the first mixture is compacted; the compaction pressure is 2.5~7MPa and the time is 3~12min. The magnesium shavings have a width of 2-15 mm, a length of 10-20 mm, and a thickness of 0.1-1.5 mm; the amount of magnesium shavings added in each aluminothermic reduction reaction is 100-300 g. The magnesium strip has a width of 10~30mm, a length of 100~200mm, a thickness of 0.1~1.5mm, and a usage of 150~250g.

[0037] Example 1 This embodiment provides a tantalum-based alloy, the preparation method of which includes the following steps: (1) Mix 34 kg of aluminum granules, 35.7 kg of tantalum pentoxide, 8.1 kg of titanium oxide, 6 kg of aluminum fluoride and 16 kg of potassium chlorate in proportion to obtain the first mixture; 6 kg of aluminum granules, 6.3 kg of tantalum pentoxide, 1.4 kg of titanium oxide, 3 kg of potassium chlorate, 1 kg of aluminum fluoride, and 1.5 kg of calcium fluoride were mixed evenly in proportion to obtain the second mixture. (2) In the direction from bottom to top, the first mixture, the second mixture and magnesium shavings are laid in the corundum crucible in sequence. Magnesium strips are used as igniters (when the magnesium strips are half burned, the lit magnesium strips are added to the mixture). After ignition, the aluminothermic reduction reaction occurs. Then, the cooling treatment and surface finishing treatment are carried out in sequence to obtain a tantalum-based alloy with a thickness of 8 cm and a weight of 58.6 kg. Before laying the second mixture, the first mixture is also compacted; the compaction pressure is 3 MPa and the time is 6 min. The magnesium shavings are 5 mm wide, 14 mm long, and 0.3 ± 0.1 mm thick; the amount of magnesium shavings added in each aluminothermic reduction reaction is 200 g. The magnesium strip has a width of 20mm, a length of 150mm, a thickness of 0.3±0.1mm, and a usage of 200g.

[0038] The metallographic image of the tantalum-based alloy described in this embodiment is as follows: Figure 1 As shown, the scanning electron microscope image is as follows: Figure 2 As shown, the elemental distribution diagram of Ta is as follows: Figure 3 As shown; The sampling and analysis results of the tantalum-based alloy described in this embodiment are shown in Table 1, and the microscopic phase region point scanning segregation is shown in Table 2.

[0039] Table 1 Table 2 As shown in Table 1, the macroscopic segregation of tantalum in the tantalum-based alloy provided in this embodiment is only 0.77 wt%, which is much lower than that of aluminum-tantalum alloy (1~5 wt%). It also has good microscopic purity. SEM surface scanning revealed that tantalum elements are evenly distributed throughout the field of view. Point scanning of the main elements in different phase regions revealed that the range between tantalum-poor phase and tantalum-rich phase is only 18.32 wt%, indicating high alloy quality.

[0040] Example 2 This embodiment provides a tantalum-based alloy, the preparation method of which includes the following steps: (1) Mix 31 kg of aluminum granules, 37.5 kg of tantalum pentoxide, 8.5 kg of titanium oxide, 6 kg of aluminum fluoride and 7 kg of potassium chlorate in proportion to obtain the first mixture material; 8 kg of aluminum granules, 6.5 kg of tantalum pentoxide, 1.5 kg of titanium oxide, 3 kg of potassium chlorate, 0.8 kg of aluminum fluoride, and 1.2 kg of calcium fluoride were mixed evenly in a certain proportion to obtain a second mixture. (2) In the direction from bottom to top, the first mixture, the second mixture and magnesium shavings are laid in the corundum crucible in sequence. Magnesium strips are used as igniters (when the magnesium strips are half burned, the lit magnesium strips are added to the mixture). After ignition, the aluminothermic reduction reaction occurs. Then, the cooling treatment and surface finishing treatment are carried out in sequence to obtain a tantalum-based alloy with a thickness of 7.5 cm and a weight of 58 kg. Before laying the second mixture, the first mixture is also compacted; the compaction pressure is 7 MPa and the time is 3 min. The magnesium shavings are 2 mm wide, 10 mm long, and 0.6 ± 0.1 mm thick; the amount of magnesium shavings added in each aluminothermic reduction reaction is 100 g. The magnesium strip has a width of 10mm, a length of 200mm, a thickness of 0.5±0.1mm, and a usage of 150g.

[0041] The sampling and analysis results of the tantalum-based alloy described in this embodiment are shown in Table 3.

[0042] Table 3 Example 3 This embodiment provides a tantalum-based alloy, the preparation method of which includes the following steps: (1) Mix 36 kg of aluminum granules, 36 kg of tantalum pentoxide, 9 kg of titanium oxide, 9 kg of aluminum fluoride and 15 kg of potassium chlorate in proportion to obtain the first mixture material; 4 kg of aluminum granules, 4 kg of tantalum pentoxide, 1 kg of titanium oxide, 1.67 kg of potassium chlorate, 0.25 kg of aluminum fluoride, and 0.25 kg of calcium fluoride are mixed evenly in a certain proportion to obtain a second mixture. (2) In the direction from bottom to top, the first mixture, the second mixture and magnesium shavings are laid in the corundum crucible in sequence. Magnesium strips are used as igniters (when the magnesium strips are half burned, the lit magnesium strips are added to the mixture). After ignition, the aluminothermic reduction reaction occurs. Then, the cooling treatment and surface finishing treatment are carried out in sequence to obtain 58.3 kg of the tantalum-based alloy. Before laying the second mixture, the first mixture is compacted; the compaction pressure is 2.5 MPa and the time is 12 min. The magnesium shavings are 15mm wide, 20mm long, and laid with a thickness of 1.2±0.1mm; the amount of magnesium shavings added in each aluminothermic reduction reaction is 300g. The magnesium strip has a width of 30mm, a length of 100mm, a thickness of 1.2±0.1mm, and a usage of 250g.

[0043] Example 4 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the mass ratio of tantalum pentoxide in the first mixture and the second mixture is adjusted to 6:4.

[0044] Example 5 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the mass ratio of tantalum pentoxide in the first mixture and the second mixture is adjusted to 9.5:0.5.

[0045] Example 6 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: This embodiment omits the compaction process performed on the first mixture before laying the second mixture.

[0046] Example 7 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, after laying the second mixture, a compaction process is added; the compaction process is carried out at a pressure of 5 MPa for 5 minutes.

[0047] Example 8 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the thickness of the magnesium shavings is adjusted to 2mm.

[0048] Example 9 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the amount of magnesium chips added is adjusted to 50g.

[0049] Example 10 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the amount of magnesium chips added is adjusted to 350g.

[0050] Example 11 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the mass ratio of aluminum fluoride to calcium fluoride in the second mixture is adjusted to 0.5:3.

[0051] Example 12 This embodiment provides a tantalum-based alloy, the only difference between the preparation method of the tantalum-based alloy and that of Embodiment 1 is: In this embodiment, the mass ratio of aluminum fluoride to calcium fluoride in the second mixture is adjusted to 3:1.

[0052] Comparative Example 1 This comparative example provides a method for preparing tantalum-based alloys (aluminum-tantalum 60 alloy) using a conventional ladle-out method, the method comprising the following steps: 2 kg of tantalum pentoxide, 41 kg of aluminum granules, 19 kg of potassium chlorate, and 8.5 kg of calcium fluoride were thoroughly mixed and then ignited with a magnesium strip to obtain 51 kg of aluminum-tantalum 60 alloy ingots.

[0053] The metallographic diagram of the tantalum-based alloy described in this comparative example is as follows: Figure 4 As shown, the scanning electron microscope image is as follows: Figure 5 As shown, the elemental distribution diagram of Ta is as follows: Figure 6 As shown; The sampling and analysis results of the tantalum-based alloy described in this comparative example are shown in Table 4, and the microscopic phase region point scanning segregation is shown in Table 5.

[0054] Table 4 Table 5 As shown in Table 4, the macroscopic segregation of tantalum in the tantalum-based alloy provided in this comparative example is 4.38 wt%, which is much higher than that of aluminum-tantalum-titanium alloy. The nitrogen content is also significantly higher than that of aluminum-tantalum-titanium alloy. This is because nitrogen from the air enters the alloy ingot due to splashing during the reaction, resulting in an increase in impurity content. The microscopic metallographic purity is good and is at the same level as that of aluminum-tantalum-titanium alloy. However, in the metallographic field of view, the phase region distribution of the tantalum-based alloy provided in this comparative example is significantly stronger than that of aluminum-tantalum-titanium. In the SEM field of view, the uniformity of tantalum element distribution in aluminum-tantalum-titanium is significantly better than that of aluminum-tantalum-60 alloy. Further spot scanning of the main elements in different phase regions of the two alloys revealed that the difference between tantalum-poor and tantalum-rich phases is as high as 67.89 wt%, and the macro- and micro-uniformity of the alloy is far lower than that of the aluminum-tantalum-titanium alloy provided in this invention.

[0055] Comparative Example 2 This comparative example provides a tantalum-based alloy, the preparation method of which differs from that of Example 1 only in that: In this comparative example, the aluminum fluoride in the first mixture is adjusted to an equal amount of calcium fluoride.

[0056] Comparative Example 3 This comparative example provides a tantalum-based alloy, the preparation method of which differs from that of Example 1 only in that: In this comparative example, the calcium fluoride in the second mixture is adjusted to an equal amount of aluminum fluoride, meaning that the slag-forming agent in the second mixture is only aluminum fluoride.

[0057] Comparative Example 4 This comparative example provides a tantalum-based alloy, the preparation method of which differs from that of Example 1 only in that: In this comparative example, the aluminum fluoride in the second mixture is adjusted to an equal amount of calcium fluoride, meaning that the slag-forming agent in the second mixture is only calcium fluoride.

[0058] Seven different locations (sampling points as shown) of the tantalum-based alloys provided in Examples 3-12 and Comparative Examples 2-4 above Figure 7 The alloy composition was tested (as shown in the figure), and the range is shown in Table 6.

[0059] Table 6 According to Table 1, the following points can be observed: (1) As can be seen from the comprehensive analysis of Examples 1-3, the tantalum-based alloy provided by the present invention has excellent alloy uniformity; (2) Comprehensive analysis of Examples 1 and 4-5 shows that if the mass ratio of tantalum pentoxide in the first mixture and the second mixture is too low, it will lead to insufficient separation of alumina inclusions and an increase in the oxygen content of the alloy. If it is too high, it will lead to an increase in alloy smelting losses and an increase in nitrogen content. A comprehensive analysis of Examples 1, 11-12 and Comparative Examples 3-4 shows that optimizing the content ratio of aluminum fluoride and calcium fluoride in the second mixture can effectively balance the horizontal and vertical spread rates and improve the stability between ingots. A comprehensive analysis of Example 1 and Comparative Example 2 shows that if the slag-forming agent in the first mixture is changed to calcium fluoride, the heat of reaction will decrease and the cooling rate will increase, which is not conducive to alloy homogenization. (3) Comprehensive analysis of Examples 1 and 6-7 shows that the raw material laying process in the preparation method will affect the raw material burn-off during the reaction; More specifically, omitting the compaction process of the first mixture will lead to increased alloy burn-off; adding the compaction process of the second mixture will affect the ignition speed and the stability between ingots. (4) Comprehensive analysis of Examples 1 and 8-10 shows that if the thickness of the magnesium chips is too thick, the ignition speed will be slower, and the surface area of ​​the mixture covered by the same weight of magnesium strips will be smaller, which will easily cause material loss during the reaction process. In the single-furnace preparation process, if the amount of magnesium chips added is too low, the ignition speed will be slower and the surface of the raw materials will not be completely covered. This will easily cause material loss during the reaction process. If the amount added is too high, the reaction will be less affected, but magnesium strips will be wasted.

[0060] In summary, this invention improves ignition efficiency by employing a dual-feeding method and covering the upper material with magnesium shavings, significantly reducing material loss caused by slow ignition speed and incomplete combustion in traditional furnace-side methods. Furthermore, by introducing a titanium source to form an AlTaTi compound, the uniformity of the alloy is significantly enhanced.

[0061] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A tantalum-based alloy, characterized in that, The tantalum-based alloy comprises, by mass fraction: 55-65 wt% tantalum, 6-15 wt% titanium, ≤0.05 wt% iron, ≤0.15 wt% silicon, ≤0.1 wt% oxygen, ≤0.02 wt% nitrogen, with the balance being aluminum.

2. The tantalum-based alloy according to claim 1, characterized in that, The thickness of the tantalum-based alloy is 5~10cm.

3. A method for preparing a tantalum-based alloy as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: In a bottom-up direction, the first mixture, the second mixture, and magnesium shavings are sequentially laid in the reaction crucible. After ignition, an aluminothermic reduction reaction occurs, followed by cooling and surface finishing treatments to obtain the tantalum-based alloy. The first mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, and aluminum fluoride; The second mixture comprises aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride, and calcium fluoride.

4. The preparation method according to claim 3, characterized in that, The mass ratio of tantalum pentoxide in the first mixture and the second mixture is 7~9:1~3.

5. The preparation method according to claim 4, characterized in that, The mass ratio of aluminum granules, tantalum pentoxide, titanium oxide, potassium chlorate and aluminum fluoride in the first mixture is (10~14):(11~16):(1~5):(4~7):(1~5); Preferably, the mass ratio of aluminum particles, tantalum pentoxide, titanium oxide, potassium chlorate, aluminum fluoride and calcium fluoride in the second mixture is (10~14):(11~16):(1~5):(4~7):(0.5~2):(1~2).

6. The preparation method according to any one of claims 3-5, characterized in that, Before laying the second mixture, the first mixture is also compacted. Preferably, the compaction pressure is 2.5~7 MPa; Preferably, the compaction process takes 3 to 12 minutes.

7. The preparation method according to any one of claims 3-6, characterized in that, The width of the magnesium shavings is 2~15mm; Preferably, the length of the magnesium shavings is 10-20 mm; Preferably, the thickness of the magnesium shavings is 0.1~1.5mm.

8. The preparation method according to claim 6, characterized in that, In each aluminothermic reduction reaction, the amount of magnesium shavings added is 100~300g.

9. The preparation method according to claim 3, characterized in that, The ignition material used is a magnesium strip.

10. The preparation method according to claim 9, characterized in that, The width of the magnesium strip is 10~30mm; Preferably, the length of the magnesium strip is 100~200mm; Preferably, the thickness of the magnesium strip is 0.1~1.5mm; Preferably, the amount of magnesium strip used is 150~250g.

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