CN117107136A - A low-density refractory high-entropy alloy and its preparation method and application - Google Patents

Abstract

The application discloses a low-density refractory high-entropy alloy, a preparation method and application thereof. Atomic percent of the low density refractory high entropy alloy: al:10.0 to 11.0at%; mo:10.0 to 11.0at%; nb:20.5-21.5at%; ti:25.5 to 27.0at%; v:10.0 to 11.0at%; zr:20.5-21.5at%. Its density is 6.35-6.55g/cm ³ . The alloy is prepared by a vacuum non-consumable electric arc furnace, the alloy is in a BCC structure as-cast state, and the microstructure presents dendrite morphology; after homogenization treatment and furnace cooling, dendrite structures in the alloy disappear, and a large number of precipitated phases appear, namely BCC1+BCC2+AlZr ₂ A multiphase structure; the melting point of the alloy is more than 1400 ℃, the room temperature yield strength is more than 1733MPa, the room temperature compressive strength is more than 1781MPa, the yield strength and the compressive strength at 800 ℃ are respectively more than 921MPa and 987MPa, and the yield strength and the compressive strength at 1000 ℃ are respectively higherAt 338MPa and 448MPa, the average Vickers microhardness is as high as 458.

Description

A low-density refractory high-entropy alloy and its preparation method and application

Technical field

The invention belongs to the field of high-temperature alloys, and in particular relates to a low-density refractory high-entropy alloy and its preparation method and application.

Background technique

With the continuous development of the aerospace industry, there is an urgent need for metal structural materials with excellent high-temperature mechanical properties. Nickel-based superalloys have the advantages of high-temperature strength, high-temperature oxidation resistance, hot corrosion resistance and high-temperature fatigue resistance, and have broad application prospects in the fields of aerospace and energy storage, such as jet engines and turbines; although in nickel-based superalloys Great progress has been made in the control of tissue composition and performance improvement, and has been used in some fields such as aerospace and energy storage, but it is far from reaching the level of large-scale engineering application. The reason is that there are two main problems: first, the density is relatively high (about 8.5g/cm3); second, its use at higher operating temperatures is limited by its solid solution line and melting temperature. Compared with nickel-based high-temperature alloys, high-entropy alloys using high-melting-point refractory elements have excellent high-temperature mechanical properties and occupy a pivotal position in the direction of high-temperature-resistant structural materials. However, high-entropy alloys contain 5 or more major metal elements, and the atomic ratio of each element is between 5% and 35%. They themselves have four major effects that traditional alloys do not have: high-entropy effect, lattice distortion effect , slow diffusion effect, "cocktail" effect. Reasonable element design can enable high-entropy alloys to have properties beyond traditional alloys, such as hardness, high-temperature performance, etc. In recent years, high-entropy alloys have received a lot of research, and people have initially recognized the partial influence of major elements on the physical and mechanical properties of alloys. High-entropy alloys based on refractory metal elements with very high melting points are called refractory high-entropy alloys. Refractory high-entropy alloys are mainly composed of high-melting-point elements. Therefore, the melting point is higher and the high-temperature resistance is better. At the same time, the alloy also has the effects common to high-entropy alloys and can show more excellent comprehensive properties at high temperatures. It is a High-temperature alloys with broad development prospects. The emergence of refractory high-entropy alloys provides new ideas for the development of a new generation of high-temperature materials, which are expected to meet the growing performance requirements at higher operating temperatures.

Contents of the invention

The invention discloses a low-density refractory high-entropy alloy, its preparation method and application, so as to solve any of the above and potential problems in the prior art.

In order to achieve the above object, the technical solution provided by the present invention is: a low-density refractory high-entropy alloy. The atomic percentages of each component of the low-density refractory high-entropy alloy are: Al: 10.0-11.0at%; Mo: 10.0-11.0at%; Nb: 20.5-21.5at%; Ti: 25.5-27.0at%; V: 10.0-11.0at%; Zr: 20.4-21.5at%.

Furthermore, the low-density refractory high-entropy alloy has a multi-phase structure of BCC1+BCC2+ _AlZr2 , and the melting point of the alloy is not lower than 1400°C; the density is 6.35-6.55g/ ^cm3 .

Further, the atomic percentages of each component of the low-density refractory high-entropy alloy are: Al: 10.12at%; Mo: 10.20at%; Nb: 21.48at%; Ti: 25.64at%; V: 10.98at%; Zr: 21.50at%; alloy density is 6.38g/cm ³ .

Further, the atomic percentages of each component of the low-density refractory high-entropy alloy are: Al: 10.53at%; Mo: 10.53at%; Nb: 21.06at%; Ti: 26.31at%; V: 10.53at%; Zr: 21.04at%; alloy density is 6.36g/cm ³ .

Further, the atomic percentages of each component of the low-density refractory high-entropy alloy are: Al: 10.99at%; Mo: 10.99at%; Nb: 20.5at%; Ti: 25..59at%; V: 10.99at% %; Zr: 20.94at%; alloy density is 6.36g/cm ³ .

Another object of the present invention is to provide a method for preparing the above-mentioned low-density refractory high-entropy alloy, which method specifically includes the following preparation steps:

S1) Raw material preparation: Calculate quantitative Al, Mo, Nb, Ti, V, Zr raw material blocks based on atomic percentage, and perform preprocessing;

S2) Smelting preparation: The raw material block processed in S1) is smelted multiple times using a vacuum smelting process. After homogenization heat treatment, a low-density refractory high-entropy alloy is obtained.

Further, the specific process of S1) is:

S1.1) Remove impurities and scale from the surface of the raw material block, and then accurately weigh the required raw material mass;

S1.2) All weighed raw materials are then placed in absolute ethanol for ultrasonic cleaning to remove surface impurities and dried.

Further, the specific process of S2) is:

S2.1) Before smelting, pump the vacuum to below 5×10 ^-3 Pa, and the current during smelting is 380A-400A; it must be turned over after each smelting is completed, and the smelting must be repeated at least 8 times.

S2.2) Then perform homogenization heat treatment. The specific process is: 1190℃~1210℃, 24 hours, and then cooled with the furnace.

Further, the strain rate of the low-density refractory high-entropy alloy is 0.001s ^-1 , its room temperature yield strength is not less than 1733MPa, and its compressive strength is not less than 1781MPa; its yield strength at 800°C is not less than 921MPa, and its compressive strength is not less than 921MPa. The strength is not less than 987MPa; the yield strength at 1000℃ is not less than 338MPa, and the compressive strength is not less than 448MPa.

A low-density refractory high-entropy alloy prepared by the above method is used in the field of medium and high temperature structural materials.

Beneficial effects of the present invention: Due to the adoption of the above technical solution, the low-density refractory high-entropy alloy of the present invention has a density of 6.35-6.55g/cm ³ and belongs to the low-density refractory high-entropy high-temperature alloy.

The alloy prepared by a vacuum non-consumable electric arc furnace has a BCC structure as cast, and the microstructure shows a dendrite morphology; after homogenization treatment at 1200°C for 24 hours and cooling in the furnace, the dendrite structure of the alloy disappears and a large number of precipitated phases It appears that it is a BCC1+BCC2+AlZr ₂ multiphase structure.

The alloy has a melting point greater than 1400°C and has high room temperature compression mechanical properties. Its cast room temperature compression yield strength can reach 1631MPa and the compressive strength can reach 1798MPa. The yield strength and compressive strength at 800°C reach 561MPa and 608MPa respectively. At 1000℃, they reach 144MPa and 166MPa respectively, and the average Vickers microhardness reaches 474; after homogenization treatment at 1200℃ for 24 hours and cooling in the furnace, the room temperature yield strength can reach 1733MPa, the compressive strength reaches 1781MPa, and the yield strength at 800℃ and The compressive strength reaches 921MPa and 987MPa respectively, and reaches 338MPa and 448MPa respectively at 1000℃. The average Vickers microhardness reaches 458.

Description of drawings

Figure 1 is a morphology diagram of the as-cast structure of a low-density refractory high-entropy alloy prepared using the preparation method of the present invention. (a) is 500x (b) is 10000x.

Figure 2 is a schematic diagram of the as-cast XRD analysis results of low-density refractory high-entropy alloy.

Figure 3 is a schematic diagram of the DSC experimental test results of low-density refractory high-entropy alloy.

Figure 4 is a schematic diagram of the microstructure of a low-density refractory high-entropy alloy after homogenization heat treatment for 24 hours and cooling in the furnace. (a) 100x (b) 200x (c) 500x (d) 1000x.

Figure 5 is a schematic diagram of the XRD test results of a low-density refractory high-entropy alloy after homogenization.

Figure 6 is a schematic diagram comparing stress-strain curves of as-cast compression tests of low-density refractory high-entropy alloys; (a) is room temperature (b) is high temperature 800°C and 1000°C.

Figure 7 is a schematic diagram comparing the stress-strain curves of the compression test of low-density refractory high-entropy alloy after homogenization heat treatment for 24 hours and cooling in the furnace; (a) is at room temperature (b) is at high temperature of 800°C and 1000°C.

Detailed ways

The technical solution of the present invention will be further described below with reference to specific embodiments and drawings.

The embodiment of the present invention provides the design, preparation and performance of a refractory high-entropy alloy, including the following processes:

Ingredients Design:

In order to obtain refractory high-entropy alloy materials with low density, low-density refractory alloy elements with lower density are first selected, including titanium (ρ=4.54g/cm ³ ), vanadium (ρ=6.11g/ cm ³ ), zirconium (ρ = 6.50 g/cm ³ ), niobium (ρ = 8.57 g/cm ³ ) and molybdenum (ρ = 10.22 g/cm ³ ). Secondly, in order to further reduce the alloy density, aluminum (ρ=2.70g/cm ³ ) was added. Finally, a detailed calculation and analysis of the thermodynamics and empirical criteria of high-entropy alloys can be performed to determine the system stability of the alloy, the formation tendency of intermetallic compounds, and the formation tendency of solid solution phases, etc.

The stability of an alloy system can be judged by calculating formula (1). The smaller the value of Gibbs free energy ΔG _mix , the more stable the alloy system is. When ΔH _mix is the same, the larger the ΔS _mix and the smaller the ΔG _mix , the more stable the system becomes. When the value of ΔH _mix is much higher than the entropy value required to form intermetallic compounds, the system has a strong tendency to form a simple solid solution. When the absolute temperature T increases, ΔG _mix decreases and the system stability is enhanced. When ΔH _mix is positive, the greater the value, the more significant the repulsion between elements; conversely, when ΔH _mix is negative, the smaller the value, the greater the attraction between elements, and the formation of intermetallic compounds will be more easy. The calculation formulas of ΔH _mix and ΔS _mix are shown in equations (2) and (3).

ΔG _mix =ΔH _mix -TΔS _mix (1)

where c _i is the element atomic ratio, R (8.314J·k ^-1 ·mol ^-1 ) is the gas constant, and Ω _ij is the canonical solution interaction parameter between the i-th and j-th elements.

Another criterion is the entropy effect criterion, as shown in equation (4):

Ω is the interaction parameter between elements, and Ω is defined to compare the comprehensive effects of ΔH _mix and ΔS _mix on phase formation. When Ω>1, it indicates that the driving force given by the mixing entropy is greater than the resistance caused by the mixing enthalpy, and the system is easy to form a simple solid solution; conversely, when Ω≤1, the driving force is less than the resistance, and intermetallic compounds are easily produced in the system, and at the same time, Cause component segregation.

In addition, there are solid solution criteria, as shown in equation (5);

where δ is the atomic size difference, c _i is the element atomic ratio, r _i is the element atomic radius, is the average atomic radius. A large number of experimental test results show that when Ω ≥ 1.1 and δ ≤ 6.6, the high-entropy alloy system tends to form a simple solid solution.

In addition, the valence electron concentration (VEC) can well describe the stability of BCC and FCC solid solutions. Its calculation formula is as follows:

where c _i is the atomic percentage of each element and VEC _i is the valence electron concentration of each element. With the help of VEC, the structure of the predicted phase can be judged. A high VEC (>8.0) will tend to form the FCC phase, and the opposite (<6.87) will tend to form the BCC phase, while values in the middle (ie, between 8.0 and 6.87) will tend to form the BCC phase. Resulting in the formation of a mixture of FCC and BCC phases.

The electronegativity standard deviation Δχ is also an important criterion. The more likely a high-entropy alloy is to form a compound, the larger its electronegativity standard deviation is. The calculation formula of Δχ is as shown in formula (7), where c _i is each The atomic percentage of an element; χ _i is the Pauling electronegativity of element i, is the arithmetic mean of electronegativity. When the alloy's Δχ>0.133, the TCP phase exists stably.

On this basis, various alloying elements were reasonably added to design a low-density refractory high-entropy alloy with an atomic percentage of 10.53Al-10.53Mo-21.06Nb-26.31Ti-10.53V-21.04Zr. Table 1 shows the calculation results of alloy thermodynamic parameter criteria. It can be seen that the alloy is easy to form a BCC structure, has a solid solution strengthening effect, and has a tendency to form solid solution + intermetallic compounds, and a TCP phase is likely to exist.

Table 1 Calculation results of thermodynamic parameters of low-density refractory high-entropy alloys

Example 1:

The atomic percentages of each component of a low-density refractory high-entropy alloy are: Al: 10.53at%; Mo: 10.53at%; Nb: 21.06at%; Ti: 26.31at%; V: 10.53at%; Zr: 21.04at%, the following are the preparation steps of a new type of low-density refractory high-entropy alloy:

Raw material preparation: Calculate and take a quantitative amount of Al, Mo, Nb, Ti, V, and Zr raw material blocks. Use sandpaper to polish the raw material blocks to remove surface impurities and oxide scale caused by cutting, and then accurately weigh the required raw materials on a balance. Afterwards, all weighed raw materials are placed in absolute ethanol for ultrasonic cleaning to remove surface impurities and dried;

Smelting preparation: Put the raw materials into a small vacuum electric arc furnace copper crucible and smelt to obtain a new type of refractory high-entropy alloy. The current requirement during smelting is 380A-400A. Before smelting, the vacuum electric arc furnace must be pumped to 5×10 ^-3 Pa. the following. It needs to be turned over every time the smelting is completed, and the smelting is repeated at least 8 times, and an ingot of the alloy will be obtained;

Table 2 shows the density results of three tests by the Archimedes method. It can be seen that the average density of the alloy is 6.36g/cm ³ , which is a low-density refractory high-entropy alloy. Figure 1 is a backscattered electron image of the as-cast structure morphology of a new type of refractory high-entropy alloy prepared by vacuum electric arc furnace melting. An obvious dendrite structure can be seen. Different contrasts reflect different element distributions. The dendrite stems are rich in Metal elements with larger atomic numbers are collected, while elements with smaller atomic numbers are enriched in the dendrites. Table 3 shows the point analysis results of EDS. It can be seen that Mo, Zr, Al and Nb are segregated, and the dendrites are enriched. It contains Mo and Nb, and is rich in Al and Zr between dendrites. The distribution of Ti and V is basically uniform. The overall composition analysis results are very close to the design composition, indicating that no obvious volatilization of low-melting point elements occurs during the smelting process. Figure 2 shows the XRD analysis results of the as-cast alloy. The results show that the V0.5 alloy has two BCC structural peaks, and no peaks other than BCC are observed.

Table 2 Alloy density test results

Table 3 Alloy EDS analysis results (at%)

Figure 3 shows the DSC experimental test results of low-density refractory high-entropy alloy. According to the results, it can be seen that the melting point of the alloy is higher than 1400°C. The homogenization process of the alloy needs to comprehensively consider issues such as segregation, melting in low melting point areas, grain growth and oxidation. The homogenization temperature cannot be set too high, so the homogenization temperature is set to 1190°C ~ 1210°C and the time is 24 hours. Allow to cool in the oven. Figure 4 shows the structural morphology of the new refractory high-entropy alloy after 24 hours of homogenization heat treatment at 1190°C ~ 1210°C and cooling in the furnace. It can be seen that the dendritic morphology has disappeared, and many phases with contrasts that are obviously different from the matrix have been generated. A large number of rod-shaped The needle-like, massive or granular phases are distributed in the matrix in the form of continuous chains. Figure 5 shows the XRD analysis results of the homogenized alloy. It can be seen that the homogenized alloy contains peaks of BCC1 and BCC2 structures, as well as a large amount of precipitated AlZr ₂ phase.

Table 4 shows the results of three Vickers hardness (HV0.5) tests on different parts of the low-density refractory high-entropy alloy as cast and after homogenization treatment at 1200°C for 24 hours and cooling in the furnace. It can be found that the hardness value of the alloy is higher. HV0.5 reaches above 474 on average, and reaches 458 after homogenization.

Table 4 Alloy Vickers hardness HV0.5 test results

The stress-strain curve of the cast alloy compression test is shown in Figure 6. The strain rate is 0.001s ^-1 . The cast room temperature compression yield strength can reach 1631MPa, and the compressive strength can reach 1798MPa. At 800℃, they reach 561MPa and 608MPa respectively. At 1000°C, they reached 144MPa and 166MPa respectively; after 24 hours of furnace cooling through homogenization treatment at 1200°C, the compression test stress-strain curve is shown in Figure 7. The strain rate is still 0.001s ^-1 , and its room temperature yield strength can reach 1733MPa, the compressive strength reaches 1781MPa, 921MPa and 987MPa respectively at 800℃, and 338MPa and 448MPa respectively at 1000℃. After homogenization treatment, the high-temperature yield strength of the alloy is significantly improved.

Example 2:

The atomic percentages of each component of a low-density refractory high-entropy alloy are: Al: 10.14at%; Mo: 10.22at%; Nb: 21.50at%; Ti: 25.66at%; V: 10.98at%; Zr: 21.50at%; alloy density is 6.38g/cm ³ .

Preparation steps of low-density refractory high-entropy alloy:

Raw material preparation: Calculate and take a quantitative amount of Al, Mo, Nb, Ti, V, and Zr raw material blocks. Use sandpaper to polish the raw material blocks to remove surface impurities and oxide scale caused by cutting, and then accurately weigh the required raw materials on a balance. Afterwards, all weighed raw materials are placed in absolute ethanol for ultrasonic cleaning to remove surface impurities and dried;

Smelting preparation: Put the raw materials into a small vacuum electric arc furnace copper crucible and smelt to obtain a new type of refractory high-entropy alloy. The current requirement during smelting is 380A-400A. Before smelting, the vacuum electric arc furnace must be pumped to 5×10 ^-3 Pa. the following. It needs to be turned over every time the melting is completed, and the melting is repeated at least 8 times to obtain an ingot of the alloy; the average density of the alloy is 6.38g/cm ³ ,

Example 3:

The atomic percentages of each component of a low-density refractory high-entropy alloy are: Al: 10.99at%; Mo: 10.99at%; Nb: 20.5at%; Ti: 25.59at%; V: 10.99at%; Zr: 20.94at%; Preparation steps of low-density refractory high-entropy alloy:

Raw material preparation: Calculate and take a quantitative amount of Al, Mo, Nb, Ti, V, and Zr raw material blocks. Use sandpaper to polish the raw material blocks to remove surface impurities and oxide scale caused by cutting, and then accurately weigh the required raw materials on a balance. Afterwards, all weighed raw materials are placed in absolute ethanol for ultrasonic cleaning to remove surface impurities and dried;

Smelting preparation: Put the raw materials into a small vacuum electric arc furnace copper crucible and smelt to obtain a new type of refractory high-entropy alloy. The current requirement during smelting is 380A-400A. Before smelting, the vacuum electric arc furnace must be pumped to 5×10 ^-3 Pa. the following. It needs to be turned over every time the melting is completed, and the melting is repeated at least 8 times to obtain an ingot of the alloy; the average density of the alloy is 6.36g/cm ³ .

The above is a detailed introduction to a new type of low-density refractory high-entropy alloy provided by the embodiments of the present application. The description of the above embodiments is only used to help understand the method and the core idea of the present application; at the same time, for those of ordinary skill in the art, there will be changes in the specific implementation and application scope based on the ideas of the present application. In summary, the contents of this specification should not be construed as limiting this application.

For example, certain words are used in the description and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and the claims do not use differences in names as a means to distinguish components; rather, differences in functions of the components serve as a criterion for distinction. For example, the words "include" and "include" mentioned in the entire description and claims are open-ended terms, so they should be interpreted as "includes/includes but is not limited to." "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The following descriptions of the specification are preferred implementation modes for implementing the present application. However, the descriptions are for the purpose of illustrating the general principles of the present application and are not intended to limit the scope of the present application. The scope of protection of this application shall be determined by the appended claims.

It should also be noted that the terms "includes", "includes" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a good or system including a list of elements includes not only those elements but also those not expressly listed other elements, or elements inherent to the product or system. Without further limitation, an element defined by the statement "comprises a..." does not exclude the presence of other identical elements in the goods or systems that include the stated element.

It should be understood that the term "and/or" used in this article is only an association relationship describing related objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A alone exists, and A and A exist simultaneously. B, there are three situations of B alone. In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Other combinations, modifications and environments, and can be modified through the above teachings or technology or knowledge in related fields within the scope of the application concept described herein. Any modifications and changes made by those skilled in the art that do not deviate from the spirit and scope of this application shall be within the protection scope of the appended claims of this application.

Claims (10)

1. A low-density refractory high-entropy alloy, characterized in that: the atomic percentages of each component of the low-density refractory high-entropy alloy are: Al: 10.0-11.0at%; Mo: 10.0-11.0at%; Nb: 20.5-21.5at%; Ti: 25.5-27.0at%; V: 10.0-11.0at%; Zr: 20.4-21.5at%. 2. The low-density refractory high-entropy alloy according to claim 1, characterized in that the low-density refractory high-entropy alloy has a multi-phase structure of BCC1+BCC2+ _AlZr2 , and the melting point of the alloy is not less than 1400 ℃; density is 6.35-6.55g/cm ³ . 3. The low-density refractory high-entropy alloy according to claim 1, characterized in that the atomic percentage of each component of the low-density refractory high-entropy alloy is: Al: 10.14at%; Mo: 10.22at% ; Nb: 21.50at%; Ti: 25.66at%; V: 10.98at%; Zr: 21.50at%; alloy density is 6.38g/cm ³ . 4. The low-density refractory high-entropy alloy according to claim 1, characterized in that the atomic percentage of each component of the low-density refractory high-entropy alloy is: Al: 10.53at%; Mo: 10.53at% ; Nb: 21.06at%; Ti: 26.31at%; V: 10.53at%; Zr: 21.04at%; alloy density is 6.37g/cm ³ . 5. The low-density refractory high-entropy alloy according to claim 1, characterized in that the atomic percentage of each component of the low-density refractory high-entropy alloy is: Al: 10.99at%; Mo: 10.99at% ; Nb: 20.5at%; Ti: 25.59at%; V: 10.99at%; Zr: 20.94at%; alloy density is 6.36g/cm ³ . 6. A method for preparing the low-density refractory high-entropy alloy according to any one of claims 1-5, characterized in that: the method specifically includes the following preparation steps: S1) Raw material preparation: Calculate quantitative Al, Mo, Nb, Ti, V, Zr raw material blocks based on atomic percentage, and perform preprocessing; S2) Smelting preparation: The raw material block processed in S1) is smelted multiple times using a vacuum smelting process. After homogenization heat treatment, a low-density refractory high-entropy alloy is obtained. 7. The method according to claim 6, characterized in that the specific process of S1) is: S1.1) Remove impurities and scale from the surface of the raw material block, and then accurately weigh the required raw material mass; S1.2) All weighed raw materials are then placed in absolute ethanol for ultrasonic cleaning to remove surface impurities and dried. 8. The method according to claim 6, characterized in that the specific process of S2) is: S2.1) Before smelting, pump the vacuum to below 5×10 ^-3 Pa, and the current during smelting is 380A-400A; it needs to be turned over after each smelting is completed, and the smelting must be repeated at least 8 times; S2.2) Then perform homogenization heat treatment. The specific process is: the temperature is 1190°C ~ 1210°C, the time is 22-26 hours, and the furnace is cooled. 9. The method according to claim 6, characterized in that the strain rate of the low-density refractory high-entropy alloy is 0.001s ^-1 , its room temperature yield strength is not less than 1733MPa, and the compressive strength is not less than 1781MPa; The yield strength at 800℃ is not less than 921MPa, and the compressive strength is not less than 987MPa; at 1000℃, the yield strength is not less than 338MPa, and the compressive strength is not less than 448MPa. 10. A low-density refractory high-entropy alloy prepared by the method of any one of claims 6-9 is used in the field of high-temperature structural materials.