High-temperature-oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material and preparation method thereof

Abstract

The invention discloses a high-temperature-oxidation-resistant titanium-tantalum-zirconium-niobium high-entropy alloy material and a preparation method thereof, and relates to the technical field of high-temperature alloy materials. The titanium-tantalum-zirconium-niobium high-entropy alloy serves as a matrix, regulation and control elements oxygen and vanadium are introduced, directional optimization of oxidation resistance and mechanical performance is achieved, the oxidation rate reaches 8.1178 * 10 <-10 > mg < 2 >. Cm <-4 >. S <-1 > after the alloy is subjected to static oxidation for 24 hours at the temperature of 900 DEG C by doping oxygen, a compact and stable oxidation film is formed on the surface, and the high-temperature oxidation resistance is remarkably improved; and the room-temperature tensile property is improved by adding the vanadium element. The high-temperature-oxidation-resistant titanium-tantalum-zirconium-niobium high-entropy alloy material provided by the invention realizes directional optimization of performance and diversified expansion of a material system, and is suitable for application requirements in the fields of aerospace engine hot end parts, high-temperature structural parts and the like; the problems that an existing alloy is limited in oxidation resistance, insufficient in mechanical property and complex in preparation process are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of superalloy materials, and particularly relates to a titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance and a preparation method thereof. Background Art

[0002] As an emerging alloy system, high-entropy alloys exhibit excellent comprehensive properties due to their multi-principal element design concept and special high-entropy effect, lattice distortion effect, and slow diffusion effect, and particularly show broad application prospects in the field of high-temperature structural materials. The TiTaZrNb-based high-entropy alloy, as a class of medium-density refractory metal high-entropy alloys without aluminum and chromium, has good thermal stability, high melting point, and corrosion resistance, and has received extensive attention.

[0003] However, currently, the TiTaZrNb-based high-entropy alloy still faces two prominent problems in engineering applications: First, its oxidation resistance is limited. Since this system lacks elements that can form a stable and dense oxide film, it is easy to form a loose and non-protective oxide layer in a high-temperature oxidation environment, resulting in a high oxidation rate and poor durability; Second, its mechanical properties need to be improved. Although this alloy has good high-temperature stability, at room temperature or medium temperature, its strength and plasticity levels are still difficult to meet the requirements of some structural components for bearing capacity, which limits its practical application.

[0004] Summary of the Invention

[0005] Aiming at the above deficiencies in the prior art, the present invention provides a titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance and a preparation method thereof. By introducing different regulating elements, the oxidation resistance and mechanical properties of the titanium-tantalum-zirconium-niobium-based alloy are improved, effectively solving the problems of limited oxidation resistance, insufficient mechanical properties, and complex preparation process of the existing alloy.

[0006] ​To achieve the above object, the technical solution adopted by the present invention to solve its technical problems is: to provide a titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance. The above-mentioned titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance is a TiTaZrNbO high-entropy alloy material or a TiTaZrNbV high-entropy alloy material.

[0007] Further, the above-mentioned TiTaZrNbO high-entropy alloy material includes the following raw materials in atomic percentages: Ti 40-41%, Ta 26-27%, Zr 15-16%, Nb 15-15.5%, and O 2-2.5%.

[0008] Further, the above-mentioned TiTaZrNbO high-entropy alloy material includes the following raw materials in atomic percentages: Ti 41%, Ta 27%, Zr 15%, Nb 15%, and O 2%.

[0009] Further, the above-mentioned TiTaZrNbV high-entropy alloy material includes the following raw materials in atomic percentages: Ti 19.5-20.5%, Ta 19.5-20.5%, Zr 19.5-20.5%, Nb 19.5-20.5%, and V 19.5-20.5%.

[0010] Further, the above-mentioned TiTaZrNbV high-entropy alloy material includes the following raw materials in atomic percentages: Ti 20%, Ta 20%, Zr 20%, Nb 20%, and V 20%.

[0011] The preparation method of the above-mentioned titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance includes the following steps: S1. Take the particles of Ti, Ta, Zr, Nb, and TiO2 / V, polish the surface with sandpaper, and then put them into anhydrous ethanol for cleaning and drying. S2. Stack and place them in sequence from bottom to top in the order of Ti, Zr, Nb, Ta, and TiO2 blocks or in the order of Ti, Zr, V, Nb, and Ta for melting. After melting, cool to obtain the titanium-tantalum-zirconium-niobium-based high-entropy alloy material with high oxidation resistance.

[0012] The beneficial effects of adopting the above further scheme are as follows: By adjusting the element ratio, TiTaZrNbO with excellent antioxidant performance is prepared. The above high-entropy alloy is a body-centered cubic structure single-phase solid solution structure, and it has the characteristics of β-type titanium alloy. Titanium has the characteristics of high strength, high plasticity, low density, and good high-temperature stability. The refractory high-entropy alloy containing titanium can utilize the cocktail effect among the four major effects of high-entropy alloys to combine the high ductility, high melting point and other properties of high-entropy alloys and titanium itself. A large number of β-stabilizing elements, including tantalum and niobium, are introduced into the above alloy, significantly improving the stability of the β phase; at the same time, zirconium is a neutral element, which helps to maintain the stability of structural uniformity and composition distribution. Titanium, as the main base element, acts together with other transition metal elements, which helps the alloy to form a stable β-phase structure, and this structure has better oxygen diffusion inhibition ability at high temperature.

[0013] For the high-temperature antioxidant high-entropy alloy material doped with trace oxygen elements provided by the present invention, the introduced trace oxygen elements are mainly distributed in a dispersed state at grain boundaries or dendrite regions, which is beneficial to the formation of a continuous and dense passivation film, and it is not easy to peel off during the oxidation process, thereby effectively inhibiting further oxidation. This is because the pre-introduced oxygen element tends to accumulate at grain boundaries and acts as a heterogeneous nucleation point during high-temperature oxidation, accelerating the formation of a protective oxide film, forming a local oxide "barrier", and blocking the rapid diffusion path. In addition, the trace oxygen elements introduced in this way can be dissolved in the body-centered cubic structure lattice, causing lattice distortion and delaying grain boundary diffusion at high temperature, thereby inhibiting the oxidation rate.

[0014] Further, in step S1, the particle purity of Ta, Ta, Zr, Nb, V and TiO2 is greater than 99.5%.

[0015] Further, in step S1, the particle size of Ta, Ta, Zr, Nb and V is 1-3 mm.

[0016] The beneficial effects of adopting the above further scheme are as follows: Controlling the particle size of the raw material particles within the above range results in the optimal melting effect. If the particles are too large, it will lead to uneven melting, and the high-melting-point metal tantalum is likely to have unmolten cores remaining, increasing the temperature gradient of the molten pool and causing composition segregation and pore defects; if the particles are too small, they are easily blown away by the arc or oxidized prematurely, resulting in uneven element distribution or impurity introduction.

[0017] Further, in step S1, the particle size of TiO2 is 2.5-3 mm.

[0018] The beneficial effects of adopting the above further solutions are as follows: It is necessary to control the particle size of titanium dioxide particles. If the oxygen content in the alloy material is too high or unevenly distributed, it may become a crack source or a heterogeneous region, reducing the mechanical properties and corrosion resistance of the material. Unmelted oxide inclusions will become stress concentration points, reducing the high-temperature service performance of the alloy. If the oxygen content in the alloy material is too low, the solid solution strengthening effect brought by pre-introducing oxygen elements is not obvious.

[0019] Further, in step S1, ensure that the TiO2 particles are completely decomposed and evenly dispersed.

[0020] Further, in step S1, clean with ultrasonic waves for 290 - 310 s.

[0021] Further, in step S1, clean with ultrasonic waves for 300 s.

[0022] Further, in step S1, place it in a vacuum drying oven and dry at 85 - 95 °C.

[0023] Further, in step S1, place it in a vacuum drying oven and dry at 90 °C.

[0024] Further, in step S2, the TiO2 block is obtained by the following method: Fill the TiO2 particles into a mold and use a hydraulic press to press them into a TiO2 block.

[0025] Further, in step S2, during pressing, the maximum axial pressure is 25 - 35 MPa and it is maintained for 9 - 11 min.

[0026] Further, in step S2, during pressing, the maximum axial pressure is 30 MPa and it is maintained for 10 min.

[0027] Further, in step S2, the diameter of the TiO2 block is 5 - 10 mm and the thickness is 2 - 4 mm.

[0028] The beneficial effects of adopting the above further solutions are as follows: Control the oxygen release rate and reaction stability.

[0029] Further, in step S2, after pressing and forming, dry it in an environment of 110 - 130 °C for 1.5 - 2.5 h.

[0030] Further, in step S2, after pressing and forming, dry it in an environment of 120 °C for 2 h.

[0031] The beneficial effects of adopting the above further solutions are as follows: Remove adsorbed moisture.

[0032] Further, in step S2, place it in a vacuum levitation melting furnace and carry out melting by the vacuum levitation melting method.

[0033] The beneficial effects of adopting the above further solutions are as follows: The electromagnetic stirring makes the melt composition more uniform, is more energy-efficient than arc melting, and can reduce the impurity problems caused by electrodes at the same time; The oxygen release rhythm of titanium dioxide raw materials can be accurately controlled to avoid local instantaneous oxygen concentration peaks, and prevent oxidation inclusions and grain coarsening.

[0034] Further, in step S2, the metal particles are stacked from bottom to top in the order of increasing melting point.

[0035] Further, in step S2, before melting, first use a mechanical pump to evacuate to 4 - 6 Pa, then start the molecular pump and continue to evacuate to 4.5×10 -3 -5×10 -3 Pa, and fill with high-purity argon so that the pressure in the furnace is 0.5 - 0.7 atm.

[0036] Further, in step S2, before melting, first use a mechanical pump to evacuate to 5 Pa, then start the molecular pump and continue to evacuate to 5×10 -3 Pa, and fill with high-purity argon so that the pressure in the furnace is 0.6 atm.

[0037] Further, in step S2, during melting, high-frequency electromagnetic induction heating is adopted.

[0038] The beneficial effects of adopting the above further solutions are as follows: The sample is suspended by electromagnetic force without crucible support, realizing pollution-free operation during the melting process.

[0039] Further, in step S2, double-sided melting is completed by adopting a stepwise temperature increase method.

[0040] Further, in step S2, during melting, three-stage power control is adopted.

[0041] Further, in step S2, during melting, first adjust the power to 90 - 110 kW and maintain for 4 - 6 min, then adjust the power to 110 - 130 kW and maintain for 4 - 6 min, then adjust the power to 130 - 150 kW and maintain for 4 - 6 min, and finally adjust the power to 180 - 200 kW and keep it for 8 - 10 min at 1600 - 1700 °C for holding and melting.

[0042] Further, in step S2, during melting, first adjust the power to 100 kW and maintain for 5 min, then adjust the power to 120 kW and maintain for 5 min, then adjust the power to 140 kW and maintain for 5 min, and finally adjust the power to 190 kW and keep it for 9 min at 1650 °C for holding and melting.

[0043] Further, in step S2, during melting, completely turn over and remelt 3 - 5 times.

[0044] The beneficial effects of adopting the above further scheme are as follows: improving the uniformity of the distribution of each component of the alloy.

[0045] Further, in step S2, the melting is repeated 5 - 7 times.

[0046] The beneficial effects of adopting the above further operation are as follows: ensuring full homogenization of the composition and eliminating macroscopic compositional segregation.

[0047] Further, in step S2, after the melting is completed, it is cooled in the furnace for 25 - 35 min.

[0048] Further, in step S2, after the melting is completed, it is cooled in the furnace for 30 min.

[0049] Further, in step S2, during the cooling process, a directional solidification die or a cold zone seeding control method is adopted to regulate the solidification structure.

[0050] The beneficial effects of adopting the above further scheme are as follows: obtaining a dense and refined alloy ingot.

[0051] A method for evaluating the oxidation resistance of the above high - temperature oxidation - resistant titanium - tantalum - zirconium - niobium - based high - entropy alloy material includes the following steps: subjecting the high - temperature oxidation - resistant titanium - tantalum - zirconium - niobium - based high - entropy alloy material to static isothermal oxidation treatment, continuously recording the oxidation weight gain value per unit area, fitting the oxidation weight gain data as a function of time, judging whether it conforms to the parabolic law or the linear law, and at the same time, combining the shedding situation of the surface oxide and the continuity of the oxide layer to comprehensively evaluate the protection of the oxide film and the oxidation resistance of the high - temperature oxidation - resistant titanium - tantalum - zirconium - niobium - based high - entropy alloy material.

[0052] Further, the static isothermal oxidation treatment is carried out at 850 - 950 °C.

[0053] Further, the static isothermal oxidation treatment is carried out at 900 °C.

[0054] Further, the evaluation criterion is: if the oxidation weight gain data conforms to the parabolic law and there is no obvious shedding of the surface oxide, it is determined to have excellent oxidation resistance.

[0055] In summary, the present invention has the following beneficial effects: 1. The present invention proposes a new design strategy for regulating the properties of high-entropy alloys. By introducing trace oxygen elements or equiatomic ratio vanadium elements into the titanium-tantalum-zirconium-niobium-based high-entropy alloy system, the directional optimization of alloy properties is achieved. For high-temperature service environments, by introducing trace oxygen elements, their dispersed distribution is realized in the alloy matrix phase, and a dense and continuous oxide film is promoted to form in-situ during high-temperature oxidation, thereby effectively blocking the oxygen diffusion path and significantly improving the oxidation resistance and service stability of the alloy. Compared with traditional oxidation resistance means, such as surface coatings, pre-oxidation treatments or multi-step heat treatment processes, this strategy has the advantages of strong material body protection ability, simple process flow and high performance stability, avoiding performance degradation caused by problems such as local peeling and interface failure.

[0056] 2. Aiming at the actual application requirements of high-entropy alloys in terms of structural strength, the present invention introduces vanadium elements with an equiatomic ratio into the titanium-tantalum-zirconium-niobium system to form a titanium-tantalum-zirconium-niobium-vanadium high-entropy alloy, realizing a mechanical property improvement strategy mainly based on solid solution strengthening. As a transition metal with a medium atomic radius, vanadium elements can enhance the lattice distortion effect and increase the resistance to dislocation movement, thereby significantly improving the tensile strength and plasticity of the alloy.

[0057] 3. The two types of alloys provided by the present invention: TiTaZrNbO2 high-entropy alloy materials and TiTaZrNbV high-entropy alloy materials are respectively targeted at the engineering application requirements of high-temperature oxidation resistance and structural mechanical properties. By forming a systematic and functionally complementary material combination, they meet the material selection with different performance focuses in complex service environments, providing a more flexible and efficient technical path for the promotion of high-entropy alloys in the field of high-end equipment manufacturing. Brief Description of the Drawings

[0058] Figure 1 are the X-ray diffraction spectra of different alloy materials; Figure 2 are the scanning electron microscope images of different alloy materials; among which (a) is the backscattered electron image of TiTaZrNb, and (b) is the backscattered electron image of TiTaZrNbO2; Figure 3 is the X-ray energy spectrum analysis surface scan image of the backscattered electron image of TiTaZrNb; Figure 4 is the X-ray energy spectrum analysis surface scan image of the backscattered electron image of TiTaZrNbO2; Figure 5 are the continuous weight gain curves of different alloy materials after oxidation at 900 °C for 24 h; Figure 6 are the X-ray diffraction spectra of the samples of different alloy materials after oxidation at 900 °C for 24 h; Figure 7Surface morphology diagrams of oxide layers of different alloy materials; among them, (a) is the surface morphology diagram of the TiTaZrNb oxide layer, (b) is the surface morphology diagram of the TiTaZrNbO2 oxide layer, and (c) is the surface morphology diagram of the TiTaZrNbO 3.2 oxide layer; Figure 8 is the X-ray energy spectrum analysis surface scan diagram of the backscattered electron image after the oxidation of TiTaZrNb; Figure 9 is the X-ray energy spectrum analysis surface scan diagram of the backscattered electron image after the oxidation of TiTaZrNbO2; Figure 10 is TiTaZrNbO 3.2 X-ray energy spectrum analysis surface scan diagram of the backscattered electron image after oxidation; Figure 11 are the tensile stress-strain diagrams of different alloy materials; Figure 12 are the compressive stress-strain diagrams of different alloy materials. Specific implementation manners

[0059] The principles and features of the present invention are described below. The examples cited are only used to explain the present invention and are not used to limit the scope of the present invention. For those not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained by purchasing in the market.

[0060] Example 1 The TiTaZrNbO high-entropy alloy material includes the following raw materials in atomic percentages: Ti 41%, Ta 27%, Zr 15%, Nb 15%, and O 2%.

[0061] The preparation method of the above TiTaZrNbO high-entropy alloy material includes the following steps: S1. Take the particles of Ti, Ta, Zr, Nb, and TiO2. After polishing the surface with sandpaper, put them into absolute ethanol and clean them with ultrasonic waves for 300 s, and then put them into a vacuum drying oven and dry them at 90 °C. The purity of the above Ti, Ta, Zr, Nb, and TiO2 particles is greater than 99.5%. The particle size of the above Ti, Ta, Zr, and Nb particles is 1-3 mm, and the particle size of the above TiO2 particles is 2.5-3 mm; S2. Fill the TiO2 particles into a mold and press them into a TiO2 block using a hydraulic press. The diameter of the above TiO2 block is 5 - 10 mm, and the thickness is 2 - 4 mm. When pressing, the maximum axial pressure is 30 MPa and it is maintained for 10 min. After pressing and forming, it is dried in an environment of 120 °C for 2 h. Then, according to the melting point from low to high, stack and place them in order from bottom to top in the sequence of Ti, Zr, Nb, Ta, and the TiO2 block for melting. Before melting, first use a mechanical pump to evacuate to 5 Pa, then start the molecular pump and continue to evacuate to 5×10 -3 Pa, and fill in high-purity argon gas to make the pressure in the furnace 0.6 atm. Use high-frequency electromagnetic induction heating and complete double-sided melting in a stepwise temperature-rising manner. When melting, adopt a three-stage power control. First, adjust the power to 100 kW and maintain it for 5 min, then adjust the power to 120 kW and maintain it for 5 min, then adjust the power to 140 kW and maintain it for 5 min, and finally adjust the power to 190 kW and keep it for 9 min at 1650 °C for holding and melting. Completely turn it over and remelt it 3 times, repeat the melting 5 times. After the melting is completed, cool it in the furnace for 30 min to obtain the TiTaZrNbO high-entropy alloy material (TiTaZrNbO2).

[0062] Example 2 The TiTaZrNbO high-entropy alloy material includes the following raw materials in atomic percentages: Ti 40%, Ta 26%, Zr 16%, Nb 15.5%, and O 2.5%.

[0063] The preparation method of the above TiTaZrNbO high-entropy alloy material includes the following steps: S1. Take the particles of Ti, Ta, Zr, Nb, and TiO2. After polishing the surface with sandpaper, put them into absolute ethanol and clean them with ultrasonic waves for 290 s, then put them into a vacuum drying oven and dry them at 85 °C. The purity of the above Ti, Ta, Zr, Nb, and TiO2 particles is greater than 99.5%. The particle sizes of the above Ti, Ta, Zr, and Nb are 1 - 3 mm, and the particle size of the above TiO2 is 2.5 - 3 mm; S2. Fill the TiO2 particles into a mold and press them into a TiO2 block using a hydraulic press. The diameter of the above TiO2 block is 5 - 10 mm, and the thickness is 2 - 4 mm. When pressing, the maximum axial pressure is 25 MPa and it is maintained for 9 min. After pressing and forming, it is dried in an environment of 110 °C for 1.5 h. Then, according to the melting point from low to high, stack and place them in order from bottom to top in the sequence of Ti, Zr, Nb, Ta, and the TiO2 block according to the melting point size for melting. Before melting, first use a mechanical pump to evacuate to 4 Pa, then start the molecular pump and continue to evacuate to 4.5×10 -3Pa, and fill high-purity argon gas to make the pressure in the furnace 0.5 atm. Use high-frequency electromagnetic induction heating and complete double-sided melting in a stepwise temperature increase manner. During melting, adopt a three-stage power control. First, adjust the power to 90 kW and maintain it for 4 min, then adjust the power to 110 kW and maintain it for 2 min, then adjust the power to 130 kW and maintain it for 4 min, and finally adjust the power to 180 kW and hold for 8 min at 1600 °C for heat preservation melting. Completely turn over and remelt 4 times, repeat melting 6 times. After melting, cool with the furnace for 25 min to obtain the TiTaZrNbO high-entropy alloy material.

[0064] Example 3 The TiTaZrNbV high-entropy alloy material includes the following raw materials in atomic percentages: Ti 20%, Ta 20%, Zr 20%, Nb 20%, and V 20%.

[0065] The preparation method of the above TiTaZrNbV high-entropy alloy material includes the following steps: S1. Take the particles of Ti, Ta, Zr, Nb, and V. After polishing the surface with sandpaper, put them into anhydrous ethanol and clean with ultrasonic waves for 310 s, then put them into a vacuum drying oven and dry at 95 °C. The purity of the above Ti, Ta, Zr, Nb, and V particles is greater than 99.5%, and the particle size of the above Ti, Ta, Zr, Nb, and V particles is 1 - 3 mm; S2. Stack and place Ti, Zr, V, Nb, and Ta in order from bottom to top according to the melting point for melting. Before melting, first use a mechanical pump to evacuate to 6 Pa, then start the molecular pump and continue to evacuate to 5×10 -3 Pa, and fill high-purity argon gas to make the pressure in the furnace 0.7 atm. Use high-frequency electromagnetic induction heating and complete double-sided melting in a stepwise temperature increase manner. During melting, adopt a three-stage power control. First, adjust the power to 110 kW and maintain it for 6 min, then adjust the power to 130 kW and maintain it for 6 min, then adjust the power to 150 kW and maintain it for 6 min, and finally adjust the power to 200 kW and hold for 10 min at 1700 °C for heat preservation melting. Completely turn over and remelt 5 times, repeat melting 7 times. After melting, cool with the furnace for 35 min to obtain the TiTaZrNbV high-entropy alloy material (TiTaZrNbV).

[0066] Comparative Example 1 A titanium-tantalum-zirconium-niobium refractory high-entropy alloy material includes the following raw materials in atomic percentages: Ti 41%, Ta 27%, Zr 16%, and Nb 16%.

[0067] The preparation method of the above titanium-tantalum-zirconium-niobium refractory high-entropy alloy material is similar to that of Example 1 (TiTaZrNb).

[0068] Comparative Example 2 A refractory high-entropy alloy material of titanium, tantalum, zirconium and niobium, comprising the following raw materials in atomic percentages: Ti 40.7%, Ta 26.7%, Zr 14.7%, Nb 14.7% and O 3.2%.

[0069] The preparation method of the above-mentioned refractory high-entropy alloy material of titanium, tantalum, zirconium and niobium is similar to that of Example 1 (TiTaZrNb 3.2 ).

[0070] Comparative Example 3 A refractory high-entropy alloy material of titanium, tantalum, zirconium and niobium, comprising the following raw materials in atomic percentages: Ti 41.3%, Ta 27.3%, Zr 15.3%, Nb 15.3% and O 0.8%.

[0071] The preparation method of the above-mentioned refractory high-entropy alloy material of titanium, tantalum, zirconium and niobium is similar to that of Example 1.

[0072] In the above-prepared refractory high-entropy alloy material of titanium, tantalum, zirconium and niobium, no dispersed oxygen element is seen in most areas of the matrix.

[0073] Test Example 1 The TiTaZrNbO high-entropy alloy material TiTaZrNbO2 prepared in Example 1, the refractory high-entropy alloy material TiTaZrNb prepared in Comparative Example 1, and the refractory high-entropy alloy material TiTaZrNb prepared in Comparative Example 2 3.2 were cut into metal blocks with a specification of 5*5*10 mm. The upper surface was polished step by step using sandpaper. The samples were polished step by step using silicon carbide sandpaper with 400 mesh, 800 mesh, 1200 mesh and 2000 mesh respectively. After the samples were polished, X-ray diffraction tests could be carried out. When testing, the 2θ angle was set to 10-90°, and the scanning speed was 5° / min. The X-ray diffraction (XRD) pattern obtained after the test was as Figure 1 shown, Figure 1 in which BCC is a body-centered cubic structure.

[0074] It can be seen from Figure 1 that all three alloys exhibit a single-phase body-centered cubic structure. After adding oxygen element, the phase composition of the original titanium, tantalum, zirconium and niobium system is not changed, which indicates that the oxygen element is distributed in the alloy matrix in a solid solution form.

[0075] Test Example 2 Use a wire cutting machine to cut out a sample from the TiTaZrNbO2 prepared in Example 1 and the TiTaZrNb prepared in Comparative Example 1 respectively, put it into absolute ethanol and clean it with ultrasonic waves for 300 s, and then dry it with a hair dryer. After that, place the sample with the flat surface facing up for sample mounting. Adopt the method of hot mounting. Raise the mounting table, place the dry and clean specimen on the mounting cylinder of the hot mounting machine, and then lower the mounting table. Add an appropriate amount of resin powder and tighten the sealing cover. Maintain a temperature of 180 °C and a pressure of 250 bar. After an 8-minute heating-holding-cooling process, open the sealing cover, raise the test bench, and take out the mounted specimen.

[0076] Grind the sample step by step using silicon carbide sandpapers with 400 mesh, 800 mesh, 1200 mesh, and 2000 mesh respectively, and then polish it with diamond polishing paste with a particle size of 1.5 mm. After cleaning the sample and drying it with a hair dryer, place the sample under a metallurgical microscope to observe the surface scratches. If no obvious scratches are observed under 100 times magnification, the sample can be used for scanning electron microscope (SEM) characterization. The results are as Figure 2 shown. Figure 2 Among them, (a) is the backscattered electron image of TiTaZrNb, and (b) is the backscattered electron image of TiTaZrNbO2.

[0077] It can be seen from Figure 2 that the matrix composition of TiTaZrNb without doped oxygen element is uniform and single, while TiTaZrNbO2 presents a dendritic morphology.

[0078] The X-ray energy spectrum analysis (EDS) surface scan map of the backscattered electron (BSE) image of the above TiTaZrNb is as Figure 3 shown, and the X-ray energy spectrum analysis (EDS) surface scan map of the backscattered electron (BSE) image of TiTaZrNbO2 is as Figure 4 shown.

[0079] It can be seen from Figure 3 and Figure 4 that each element of the two matrix alloys is evenly distributed. The surface scan map of the refractory high-entropy alloy material of titanium tantalum zirconium niobium does not contain oxygen element, while in the surface scan map of the TiTaZrNbO2 high-entropy alloy with trace oxygen doping, oxygen element can be seen to be diffusely distributed in the matrix, and titanium, zirconium, niobium, and oxygen are enriched at the dendrites, and tantalum is enriched between the dendrites.

[0080] Test Example 3 TiTaZrNbO2 prepared in Example 1, TiTaZrNb prepared in Comparative Example 1, and TiTaZrNbO prepared in Comparative Example 2 3.2Wire cutting was carried out to obtain metal blocks with specifications of 5 mm * 5 mm * 10 mm. The samples were polished step by step with silicon carbide sandpaper, and the polishing mesh numbers were 240 mesh, 600 mesh, 800 mesh, 1200 mesh, and 2000 mesh in sequence until the surface of the sample showed a mirror surface; then, diamond polishing paste with a particle size of 1.5 mm was used to polish it until no obvious scratches could be seen under an optical microscope; the samples were placed in ethanol for ultrasonic cleaning for 5 min and then dried with a hair dryer. The net weight of the dried samples was weighed with an electronic balance with a precision of 0.0001 g. The samples were placed in an alumina crucible, and the total weight of the samples and the crucible was weighed; the crucible was placed in a tube furnace at 900 °C for 24 h of oxidation test. The samples were taken out every two hours, cooled to room temperature, and then weighed.

[0081] TiTaZrNbO2 prepared in Example 1, TiTaZrNb prepared in Comparative Example 1, and TiTaZrNbO prepared in Comparative Example 2 3.2 After oxidation at 900 °C for 24 h, the samples remained intact, and there was no obvious oxide shedding on the surfaces of TiTaZrNbO2 and TiTaZrNbO 3.2 The oxide layer of TiTaZrNbO2 was flat and very thin, indicating that the TiTaZrNbO2 high-entropy alloy material had good oxidation resistance. A small amount of oxide scale was visible on TiTaZrNb, and the oxide layer was relatively thick.

[0082] TiTaZrNbO2 prepared in Example 1, TiTaZrNb prepared in Comparative Example 1, and TiTaZrNbO prepared in Comparative Example 2 3.2 The continuous weight gain curves after oxidation at 900 °C for 24 h are as Figure 5 shown.

[0083] From Figure 5 it can be seen that through data fitting, the oxidation weight gain per unit area of the TiTaZrNb high-entropy alloy without introducing oxygen element prepared in Comparative Example 1 conforms to the linear law in the initial stage of oxidation, and its oxidation rate is 1.4512×10 -3 mg·cm -2 ·s -1 (which is 2.106×10 -6 mg 2 ·cm -4 ·s -1 ), indicating that the oxidation rate is controlled by the surface chemical reaction, the oxide film does not have protection, and the matrix alloy material is consumed quickly. The oxidation weight gain per unit area of Example 1 and Comparative Example 1 both conform to the parabolic law. For TiTaZrNbO2 prepared by doping trace oxygen element method in Example 1, its oxidation rate is only 8.1178×10 -10 mg 2 ·cm -4 ·s-1 , showing the best antioxidant performance. In contrast, the TiTaZrNbO 3.2 alloy prepared by further increasing the oxygen element addition amount in Comparative Example 2 has an oxidation rate of 1.0254×10 -9 mg 2 ·cm -4 ·s -1 , which is one order of magnitude higher than that of Example 1, showing poor antioxidant ability. This shows that by precisely controlling the addition amount of oxygen element, the antioxidant performance of TiTaZrNb-based high-entropy alloys can be optimized and regulated.

[0084] Test Example 4 The XRD spectra of the samples of TiTaZrNbO2 prepared in Example 1, TiTaZrNb prepared in Comparative Example 1, and TiTaZrNbO 3.2 prepared in Comparative Example 2 after oxidation at 900 °C for 24 h are as Figure 6 shown.

[0085] It can be Figure 6 seen that five oxides, namely titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), tantalum dioxide (TaO2), niobium pentoxide (Nb2O5), and titanium niobium oxide (TiNb2O7), are produced in all three alloys.

[0086] The samples of TiTaZrNbO2 prepared in Example 1, TiTaZrNb prepared in Comparative Example 1, and TiTaZrNbO 3.2 prepared in Comparative Example 2 were characterized by scanning electron microscopy (SEM) after oxidation at 900 °C for 24 h, and the surface morphology of the oxide layer is as Figure 7 shown, Figure 7 in which (a) is the surface morphology diagram of the TiTaZrNb oxide layer, (b) is the surface morphology diagram of the TiTaZrNbO2 oxide layer, and (c) is the surface morphology diagram of the TiTaZrNbO 3.2 oxide layer.

[0087] It can be Figure 7 seen that by observing the surface state of the oxide layer, it can be seen that a relatively thick oxide layer has formed on the surface of the sample of TiTaZrNb without doped oxygen element after oxidation at 900 °C for 24 h, and there are many obvious cracks. The discontinuity of the oxide layer indicates that part of the oxide scale has peeled off, exposing the fresh metal surface, which is likely to cause direct contact between oxygen, corrosive media, etc. and the substrate in practical applications, leading to secondary oxidation or local corrosion. From the surface morphology of the oxide layer of TiTaZrNbO2 prepared in Example 1, it can be seen that only an extremely thin oxide film has formed after oxidation of the TiTaZrNbO2 high-entropy alloy, and the oxide film is flat and continuous. The TiTaZrNbO 3.2The surface morphology of the oxide layer is continuous but uneven, presenting a convex morphology without peeling off yet.

[0088] The X-ray energy spectrum analysis (EDS) surface scan of the backscattered electron (BSE) image after the oxidation of the above TiTaZrNb is as Figure 8 shown. The X-ray energy spectrum analysis (EDS) surface scan of the backscattered electron (BSE) image after the oxidation of TiTaZrNbO2 is as Figure 9 shown. The X-ray energy spectrum analysis (EDS) surface scan of the backscattered electron (BSE) image after the oxidation of TiTaZrNbO 3.2 is as Figure 10 shown.

[0089] From Figures 8 - 10 it can be seen that in the TiTaZrNbO2 prepared in Example 1, the oxygen element is mainly concentrated within the range of the oxide thin layer, and there is only a small amount of oxygen element with a dispersed distribution introduced during melting in the matrix, indicating that the oxide thin layer plays a very good role in blocking the diffusion of oxygen element. In contrast, the oxygen elements in the TiTaZrNb prepared in Comparative Example 1 and TiTaZrNbO 3.2 prepared in Comparative Example 2 penetrate deep into the substrate.

[0090] Test Example 5 Use a wire cutting machine to cut out a sample from the TiTaZrNbV high-entropy alloy material prepared in Example 3, put it into absolute ethanol and clean it with ultrasonic waves for 300 s, and dry it with a hair dryer. Then, place the sample with the flat surface facing up for hot embedding. After embedding, grinding, and polishing, hardness testing is carried out. The hardness testing uses a dimensional tester, the indenter is 1000 g, and it lasts for 15 s. Five different points are taken for hardness testing, and the obtained hardness testing results are shown in the following table.

[0091] Table 1 Hardness Testing Results

[0092] Use a wire cutting machine to cut out a tensile specimen and a cylindrical compression specimen with a height of 8 mm and a diameter of 4 mm from TiTaZrNbV. Then, gradually polish the surfaces of the specimens, and the grinding mesh numbers are 240 mesh, 600 mesh, 800 mesh, 1200 mesh, and 2000 mesh in sequence. Then, use diamond polishing paste with a particle size of 1.5 μm to polish it to a mirror surface. After all the samples are polished, they are ultrasonically cleaned with absolute ethanol, dried on the surface, and the axial tensile and compression properties of the room temperature mechanical properties are tested using a WD-100D universal mechanical testing machine. The tensile stress-strain diagram of TiTaZrNbV is as Figure 11 shown, and the compression stress-strain diagram of TiTaZrNbV is as Figure 12 shown.

[0093] FromFigure 11 and Figure 12 It can be seen that the TiTaZrNbV alloy exhibits good mechanical properties. The tensile yield strength can reach about 1.1 GPa, and the maximum compressive strength reaches 2.5 GPa, showing high yield strength and compressive plasticity. The optimization of its mechanical properties can be attributed to the synergistic effects in the following aspects: First, the vanadium element has a relatively small atomic radius. After doping, it can cause a strong lattice distortion effect in the lattice, thus enhancing the solid solution strengthening effect of the alloy. Second, the vanadium element has a high binding energy, which can promote the stability of the multi-principal element high-entropy solid solution structure and delay the phase decomposition or the formation of brittle phases. Third, in terms of microstructure, the introduction of vanadium inhibits grain coarsening and refines the grain size, thereby significantly improving the material strength. This provides a solution for strengthening the mechanical properties of TiTaZrNb-based high-entropy alloy structural components in high-temperature service environments.

[0094] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-entropy titanium, tantalum, zirconium, and niobium alloy material resistant to high-temperature oxidation, characterized in that: The high-temperature oxidation-resistant titanium, tantalum, zirconium, and niobium series high-entropy alloy material is a TiTaZrNbO high-entropy alloy material or a TiTaZrNbV high-entropy alloy material; The TiTaZrNbO high entropy alloy material comprises the following raw materials in atomic percentage: Ti 40-41%, Ta 26-27%, Zr 15-16%, Nb 15-15.5% and O 2-2.5%; The TiTaZrNbV high entropy alloy material comprises the following raw materials in atomic percentage: Ti 19.5-20.5%, Ta 19.5-20.5%, Zr 19.5-20.5%, Nb 19.5-20.5% and V 19.5-20.5%.

2. The high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium high-entropy alloy material according to claim 1, characterized in that: The TiTaZrNbO high entropy alloy material includes the following raw materials in atomic percentage: Ti 41%, Ta 27%, Zr 15%, Nb 15% and O2%.

3. The high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 1, characterized in that: The TiTaZrNbV high entropy alloy material includes the following raw materials in atomic percentage: Ti 20%, Ta 20%, Zr 20%, Nb 20% and V 20%.

4. The method for preparing the high-temperature oxidation-resistant titanium, tantalum, zirconium, and niobium-based high-entropy alloy material according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Take Ti, Ta, Zr, Nb and TiO2 / V particles, polish the surface with sandpaper, wash them in anhydrous ethanol and dry them; S2. Ti, Zr, Nb, Ta and TiO2 blocks are stacked in the order of bottom to top or Ti, Zr, V, Nb and Ta are stacked in the order of bottom to top for smelting. After smelting, cooling is performed to obtain a titanium, tantalum, zirconium and niobium series high entropy alloy material resistant to high temperature oxidation.

5. The method for preparing a high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 4, characterized in that: In step S1, the particle size of the Ti, Ta, Zr, Nb and V is 1-3 mm, and the particle size of the TiO2 is 2.5-3 mm.

6. The method for preparing a high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 4, characterized in that: In step S2, the diameter of the TiO2 block is 5-10 mm and the thickness is 2-4 mm.

7. The method for preparing a high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 4, characterized in that: In step S2, before smelting, the vacuum is first pumped to 4-6 Pa using a mechanical pump, and then the molecular pump is turned on to continue vacuuming to 4.5×10 -3 -5.5×10 -3 Pa, and filled with high-purity argon gas to make the pressure in the furnace 0.5-0.7atm.

8. The method for preparing a high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 4, characterized in that: In step S2, high-frequency electromagnetic induction heating is used during smelting.

9. The method for preparing a high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 4, characterized in that: In step S2, during smelting, the power is first adjusted to 90-110 kW and maintained for 4-6 minutes, then adjusted to 110-130 kW and maintained for 4-6 minutes, then adjusted to 130-150 kW and maintained for 4-6 minutes, and finally adjusted to 180-200 kW and smelted at 1600-1700°C for 8-10 minutes.

10. A method for evaluating the oxidation resistance of the high-temperature oxidation-resistant titanium-tantalum-zirconium-niobium series high-entropy alloy material according to claim 1, characterized in that: The method comprises the following steps: subjecting a high-temperature oxidation-resistant titanium, tantalum, zirconium, and niobium series high-entropy alloy material to a static constant-temperature oxidation treatment, continuously recording the oxidation weight gain per unit area, fitting the oxidation weight gain data as a function of time, judging whether it conforms to a parabolic law or a linear law, and, in combination with the shedding of surface oxides and the continuity of the oxide layer, comprehensively evaluating the protectiveness of the oxide film and the oxidation resistance of the high-temperature oxidation-resistant titanium, tantalum, zirconium, and niobium series high-entropy alloy material.

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