Hf-Nb-Zr-V refractory high-entropy alloy and preparation method thereof

Abstract

The invention discloses an Hf-Nb-Zr-V refractory high-entropy alloy and a preparation method thereof, and belongs to the technical field of metal materials. The preparation method comprises the following steps: (1) weighing Hf, Nb, Zr and V raw materials according to a designed ratio; (2) putting Hf and Nb into a copper crucible for smelting according to the sequence that the low melting point is lower and the high melting point is upper, so as to obtain an Hf-Nb pre-alloy ingot; (3) Zr and V are put into a copper crucible for smelting according to the sequence that the low melting point is lower and the high melting point is upper, and a Zr-V pre-alloy ingot is obtained; and (4) putting the Hf-Nb pre-alloy ingot in the step (2) and the Zr-V pre-alloy ingot in the step (3) into a copper crucible, and smelting in an argon environment to obtain the Hf-Nb-Zr-V refractory high-entropy alloy. According to the alloy prepared through the method, the requirement limitation of the types of composition elements of a traditional high-entropy alloy is broken through, the alloy preparation cost is reduced by reducing the types of the composition elements of the alloy, meanwhile, on the basis that the types of the composition elements of the alloy are reduced, it is still guaranteed that the alloy has the excellent room temperature performance, and the alloy application range is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials and relates to a Hf-Nb-Zr-V refractory high entropy alloy and a preparation method thereof. Background Art

[0002] High entropy alloys are different from traditional engineering alloys. They are a series of complex alloys with a simple solid solution structure as the matrix, formed by mixing multiple elements in equimolar or nearly equimolar proportions. This type of alloy contains at least 5 main elements.

[0003] The systems that have been developed can be roughly divided into two categories: one is a high entropy alloy composed of period IV elements such as Fe, Co, Ni, etc. These elements have a high valence electron concentration, and the high entropy alloys formed by combination are mostly FCC structures; the other is refractory high entropy alloys (RHEAs) composed of high melting point elements such as W, Hf, Ta, Nb, etc. Since these high melting point elements have a low valence electron concentration, they are easier to form BCC structures and high entropy alloys with high melting points, often showing relatively excellent high temperature performance. However, their comprehensive room temperature performance is relatively poor, such as NbCrMo 0.5 Ta 0.5 Although the compressive yield strength of TiZr alloy can reach 1595MPa at room temperature, its elongation is only 5%.

[0004] Therefore, it is necessary to provide a Hf-Nb-Zr-V refractory high entropy alloy and a preparation method thereof, so as to break through the limitation on the number of types of main elements of the alloy, and still obtain an alloy with good comprehensive performance at room temperature on the basis of fewer constituent elements, thereby reducing the alloy manufacturing cost on the one hand, and broadening the application range of the alloy on the other hand, so that it also has good applicability at room temperature. Summary of the invention

[0005] In order to overcome the problems in the background technology, the present invention proposes a Hf-Nb-Zr-V refractory high entropy alloy and a preparation method thereof. The alloy only requires 4 constituent elements. Compared with traditional high entropy alloys, the number of constituent elements is reduced, and its manufacturing cost is also reduced. At the same time, on the basis of reducing the constituent elements, the comprehensive performance of the alloy at room temperature is improved.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing a Hf-Nb-Zr-V refractory high entropy alloy, the preparation method comprising the following steps:

[0008] (1) Weigh the Hf, Nb, Zr and V raw materials according to the designed ratio.

[0009] (2) Hf and Nb are placed in a copper crucible in the order of low melting point at the bottom and high melting point at the top for smelting to obtain a Hf-Nb pre-alloyed ingot.

[0010] (3) Zr and V are placed in a copper crucible in the order of low melting point at the bottom and high melting point at the top for smelting to obtain a Zr-V pre-alloy ingot.

[0011] (4) placing the Hf-Nb pre-alloyed ingot in step (2) and the Zr-V pre-alloyed ingot in step (3) into the same crucible, and smelting them in an argon environment to obtain a Hf-Nb-Zr-V refractory high entropy alloy.

[0012] Preferably, in the raw materials, the purity of Hf, Nb, Zr and V is above 99.5wt%.

[0013] Preferably, among the raw materials, Hf, Zr and V are in the form of cylindrical particles, and Nb is in the form of flaky particles.

[0014] Preferably, in step (2) and step (3), the melting is reversed for no less than 2 times.

[0015] Preferably, in step (4), the pre-alloyed ingot is smelted at least 15 times.

[0016] Preferably, in step (4), a vacuum arc furnace is used to carry out arc melting on the pre-alloyed ingot, and the vacuum degree is 1×10 -4 ~5×10 -4 Pa, filled with high purity argon gas to 0.03 ~ 0.05MPa.

[0017] Another aspect of the present invention provides a Hf-Nb-Zr-V alloy prepared by the above preparation method, in which the atomic ratio of the constituent elements is Hf:Nb:Zr:V=1:1:1:1.

[0018] Preferably, in the alloy, each constituent element has the same crystal structure.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention reduces the number of elements in the alloy, breaking through the limitation that the traditional high entropy alloy must have at least five elements, and can significantly reduce the overall cost of alloy manufacturing.

[0021] 2. The present invention places the metal with a low melting point at the bottom and the metal with a high melting point at the top, and first melts them to obtain a pre-alloyed ingot, and then melts the pre-alloyed ingot to obtain the final alloy. The method is simple and easy, and the prepared alloy has good room temperature performance.

[0022] 3. The alloy of the present invention has both BBC phase and Laves phase, and its room temperature yield strength can reach 1428 MPa, its compression strength can reach 1721 MPa, and its strain energy can reach 18.1%.

[0023] 4. The present invention reduces the types of constituent elements in the alloy, so that the constituent elements in the alloy have the same crystal structure, which is beneficial to improving the room temperature performance of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 2 is the XRD spectrum of the alloy of the present invention, wherein the horizontal axis 2θ (degrees) represents the diffraction angle (degrees); and the vertical axis intensity represents the intensity (au).

[0025] Figure 2 This is a scanning electron microscope image of the alloy of the present invention.

[0026] Figure 3 This is the energy spectrum picture of the alloy of the present invention.

[0027] Figure 4 Graph showing the room temperature compressive stress-strain curve of the alloy of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with specific embodiments.

[0029] In the embodiments and comparative examples of the present invention, the chemical reagents described in detail were all commercially available analytically pure for experiments.

[0030] Example 1

[0031] In this embodiment, Hf-Nb-Zr-V alloy is prepared by the following method:

[0032] (1) Raw material preparation: When preparing the alloy, four metal raw materials of Hf, Zr, V and Nb with a purity higher than 99.5wt.% are prepared. Among them, the raw materials Hf, Zr and V are cylindrical particles of 3mm*3mm, and Nb is flake particles with a thickness of 1-6mm.

[0033] (2) First, the raw materials are pretreated: Hf, Nb, Zr and V are first ultrasonically cleaned with anhydrous ethanol for 15 minutes, and then dried in a drying oven (temperature 80°C, time 2 hours). After pretreatment, each raw material is accurately weighed according to the atomic ratio of Hf:Nb:Zr:V=1:1:1:1.

[0034] (3) Preparation of Hf-Nb pre-alloyed ingots: The pre-alloyed ingots of the present invention are prepared in a WCE300 tungsten pole magnetron arc furnace, and the crucible used for smelting is a water-cooled copper crucible.

[0035] The raw materials hafnium (Hf) and niobium (Nb) were placed into a water-cooled copper crucible in the order of melting point from low to high, with the low melting point raw material at the bottom and the high melting point raw material at the top. Then the arc furnace was evacuated until the vacuum reached 5×10 -4 After Pa, 0.05MPa of high-purity argon is filled. There are multiple water-cooled copper crucibles in the arc furnace melting chamber. The arc gun of the arc furnace is aimed at the particles in the crucible to start arc melting. In addition to the crucible for smelting the metal of the present invention, there is also a crucible containing titanium ingots in the arc furnace melting chamber. Before starting the alloy smelting of the present invention, the arc gun is first aimed at the crucible containing the titanium ingot, and the titanium ingot is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy smelting process. The smelting is carried out under the protection of argon, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the smelting is turned at least twice.

[0036] (4) Preparation of Zr-V pre-alloyed ingots: The raw materials zirconium (Zr) and vanadium (V) are placed in a water-cooled copper crucible in the order of melting point from low to high, with the low melting point raw material at the bottom and the high melting point raw material at the top. Then, the electric arc furnace is evacuated until the vacuum reaches 5×10 -4 After reaching 0.05 MPa, high-purity argon gas is filled in. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon gas, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the melting is turned over at least 2 times.

[0037] (5) Place the Hf-Nb pre-alloyed ingot and the Zr-V pre-alloyed ingot into a water-cooled copper crucible, and then evacuate the arc furnace until the vacuum reaches 5×10 -4 After the titanium ingot reaches 0.05 MPa, it is filled with 0.05 MPa of high-purity argon. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the final alloy, the melting number is not less than 15 times.

[0038] After the alloy smelting is completed, the furnace is cooled and then filled with air. The cavity is opened and the alloy ingot is taken out to obtain the cast alloy. The chemical composition of the alloy is shown in Table 1.

[0039] Table 1 Chemical composition of Hf-Nb-Zr-V alloy (at.%)

[0040] area Hf Nb Zr V Overall ingredients 24.7 25.2 25.6 24.5

[0041] The properties of the alloy prepared in this example were tested:

[0042] ①X-ray diffraction analysis of alloy phase structure:

[0043] Blocks of 2×5×10 mm were cut from the alloy ingot using wire cutting and rapid sawing, and polished with 400#, 800#, 1000# and 2000# water-abrasive sandpaper in turn, cleaned with alcohol, and dried with cold air. XRD analysis was performed using an XPertPro diffractometer with a 2θ range of 20-80° and a scanning speed of 6° / min. The results are as follows: Figure 1 shown.

[0044] pass Figure 1 It can be seen that according to the lattice diffraction extinction law, the three diffraction peaks in the spectrum correspond to the (110), (200), and (211) crystal planes of the BCC structural phase, indicating that the prepared refractory high entropy alloy is mainly composed of BCC phase; in addition, two diffraction peaks appear near the (110) peak (marked with diamonds in the figure) as diffraction peaks corresponding to Laves, indicating that Laves phase exists in the refractory high entropy alloy. The generation of Laves phase is due to the presence of a higher atomic ratio of Zr and V elements in the alloy, which increases the enthalpy of the alloy, thereby causing the instability of the BCC phase and producing the typical C14 Laves phase compound ZrV 2， The phase structure in the alloy system changes to BCC+Laves phase dominated by BCC phase. Compared with the single BCC phase, the existence of the composite phase structure enables the alloy to have higher strength and strain performance at the same time, and the alloy has better comprehensive performance.

[0045] ② Scanning electron microscope (SEM) organization observation:

[0046] A 2×5×10mm block was cut from the alloy ingot as a sample for SEM observation. The sample was polished with 400#, 800#, 1000#, 2000# and 3000# metallographic sandpaper in turn, and then mechanically polished with 0.1μm and 0.05μm alumina polishing liquid. The sample was then ultrasonicated with alcohol for 30 minutes and dried for later use. The SEM model was FEIXL30. The SEM results are shown in Figure 2. Figure 2 shown.

[0047] pass Figure 2 It can be seen that the alloy is composed of BCC and Laves phases, and the organizational morphology is a typical cast dendrite structure.

[0048] ③ Alloy energy spectrum analysis:

[0049] The alloy was subjected to 3EDS energy spectrum analysis, and the results were as follows: Figure 3 shown.

[0050] pass Figure 3It can be seen that Hf, Nb, Zr and V are evenly distributed in the alloy without obvious segregation. The dendrite phase is mainly Nb, with a slight enrichment of Hf. The interdendritic phase is mainly rich in Zr and V.

[0051] ④Analysis of alloy mechanical properties

[0052] The sample size for room temperature mechanical properties analysis is Φ3mm×6mm, and the cylindrical end surface is polished flat with metallographic sandpaper. The room temperature compression test is carried out using an Instron 5582 electronic universal testing machine with a strain rate of 1×10 -3 / s, the test used 3 parallel samples. Figure 4 shown.

[0053] pass Figure 4 It can be seen that the yield strength of the alloy is 1428 MPa, the compressive strength is 1721 MPa, and the strain is 18.1%. The Hf-Nb-Zr-V alloy prepared by the present invention has excellent comprehensive properties.

[0054] Example 2

[0055] In this embodiment, Hf-Nb-Zr-V alloy is prepared by the following method:

[0056] (1) Raw material preparation: When preparing the alloy, four metal raw materials of Hf, Zr, V and Nb with a purity higher than 99.5wt.% are prepared. Among them, the raw materials Hf, Zr and V are cylindrical particles of 3mm*3mm, and Nb is flake particles with a thickness of 1-6mm.

[0057] (2) First, the raw materials are pretreated: Hf, Nb, Zr and V are first ultrasonically cleaned with anhydrous ethanol for 15 minutes, and then dried in a drying oven (temperature 80°C, time 2 hours). After pretreatment, each raw material is accurately weighed according to the atomic ratio of Hf:Nb:Zr:V=1:1:1:1.

[0058] (3) Preparation of Hf-Nb pre-alloyed ingots: The pre-alloyed ingots of the present invention are prepared in a WCE300 tungsten pole magnetron arc furnace, and the crucible used for smelting is a water-cooled copper crucible.

[0059] The raw materials hafnium (Hf) and niobium (Nb) are placed in a water-cooled copper crucible in order of melting point from low to high, with the low melting point raw materials at the bottom and the high melting point raw materials at the top. Then the arc furnace is evacuated until the vacuum reaches 1×10 -4After reaching 0.004 MPa, high-purity argon gas of 0.03 MPa is filled in. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon gas, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the melting is turned over at least 2 times.

[0060] (4) Preparation of Zr-V pre-alloyed ingots: The raw materials zirconium (Zr) and vanadium (V) are placed in a water-cooled copper crucible in the order of melting point from low to high, with the low melting point raw material at the bottom and the high melting point raw material at the top. Then, the electric arc furnace is evacuated until the vacuum reaches 1×10 -4 After reaching 0.004 MPa, high-purity argon gas of 0.03 MPa is filled in. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon gas, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the melting is turned over at least 2 times.

[0061] (5) Place the Hf-Nb pre-alloyed ingot and the Zr-V pre-alloyed ingot into a water-cooled copper crucible, and then evacuate the arc furnace until the vacuum reaches 1×10 -4 Pa, and then 0.03MPa of high-purity argon is filled in. First, the titanium ingots in the arc furnace melting chamber are melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. Melting is carried out under argon protection, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the final alloy, the melting number is not less than 15 times.

[0062] The properties of the alloy prepared in this example are similar to those in Example 1.

[0063] Example 3

[0064] (1) Raw material preparation: When preparing the alloy, four metal raw materials of Hf, Zr, V and Nb with a purity higher than 99.5wt.% are prepared. Among them, the raw materials Hf, Zr and V are cylindrical particles of 3mm*3mm, and Nb is flake particles with a thickness of 1-6mm.

[0065] (2) First, the raw materials are pretreated: Hf, Nb, Zr and V are first ultrasonically cleaned with anhydrous ethanol for 15 minutes, and then dried in a drying oven (temperature 80°C, time 2 hours). After pretreatment, each raw material is accurately weighed according to the atomic ratio of Hf:Nb:Zr:V=1:1:1:1.

[0066] (3) Preparation of Hf-Nb pre-alloyed ingots: The pre-alloyed ingots of the present invention are prepared in a WCE300 tungsten pole magnetron arc furnace, and the crucible used for smelting is a water-cooled copper crucible.

[0067] The raw materials hafnium (Hf) and niobium (Nb) are placed in a water-cooled copper crucible in order of melting point from low to high, with the low melting point raw materials at the bottom and the high melting point raw materials at the top. Then the arc furnace is evacuated until the vacuum reaches 3×10 -4 After reaching 0.04MPa, high-purity argon gas is filled in. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon gas, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the melting is turned over at least 2 times.

[0068] (4) Preparation of Zr-V pre-alloyed ingots: The raw materials zirconium (Zr) and vanadium (V) are placed in a water-cooled copper crucible in the order of melting point from low to high, with the low melting point raw material at the bottom and the high melting point raw material at the top. Then, the electric arc furnace is evacuated until the vacuum reaches 3×10 -4 After reaching 0.04MPa, high-purity argon gas is filled in. First, the titanium ingot in the arc furnace melting chamber is melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon gas, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the pre-alloyed ingot, the melting is turned over at least 2 times.

[0069] (5) Place the Hf-Nb pre-alloyed ingot and the Zr-V pre-alloyed ingot into a water-cooled copper crucible, and then evacuate the arc furnace until the vacuum reaches 3×10 -4 Pa, and then 0.04MPa of high-purity argon is filled in. First, the titanium ingots in the arc furnace melting chamber are melted separately to absorb the residual oxygen in the furnace, further reduce the oxygen partial pressure, and prevent oxidation during the alloy melting process. The melting is carried out under the protection of argon, and the heating current is gradually increased from 20A to 150A. In order to ensure the uniformity of the chemical composition of the final alloy, the melting number is not less than 15 times.

[0070] The properties of the alloy prepared in this example are similar to those in Example 1.

[0071] Comparative Example 1

[0072] This comparative example adopts the same method as Example 1 to prepare the alloy, except that: during the preparation of the alloy in this comparative example, no pre-alloy ingot smelting is performed, and the metal with the lower melting point among the four metals is directly placed at the bottom, and the metal with the higher melting point is placed at the top.

[0073] The performance of the alloy prepared in this comparative example is compared with that of the alloy in Example 1. Since the melting points of the four elements differ greatly and the radii of some atoms also differ greatly, they cannot be infinitely soluble in each other. If the melting point of the alloy is not indirectly lowered, the alloy cannot be melted uniformly.

[0074] Comparative Example 2

[0075] This comparative example adopts the same method as Example 1 to prepare the alloy, except that: during the preparation of the alloy in this comparative example, the metal with a lower melting point is placed on the top, and the metal with a higher melting point is placed on the bottom.

[0076] The properties of the alloy prepared in this comparative example are compared with those in Example 1. Since the process of preparing the refractory high entropy alloy according to the present invention requires faster cooling, otherwise the cooling time is too long, which will have a certain negative impact on the final alloy properties. During the smelting process, there are heat transfer and melting problems between metals. The placement method in Comparative Example 2 will cause the low-melting-point component to completely melt and cover the high-melting-point components Nb and Hf that have not yet completely melted during the smelting process, resulting in the inability to melt the alloy uniformly.

[0077] Comparative Example 3

[0078] This comparative example adopts the same method as Example 1 to prepare the alloy, except that in this comparative example, the element V is replaced by the element Ti.

[0079] Compared with Example 1, the alloy performance prepared in this comparative example is that Ti, Zr, and Hf belong to the same main group IVB, Zr and Nb are adjacent elements in the same period, and the atomic radius of these four elements is very similar, and they can be infinitely soluble in each other, so the prepared Hf-Nb-Zr-Ti refractory high entropy alloy is composed of BCC phase. However, as Ti replaces the V element, the generation of Laves phase will be reduced, and although the room temperature plasticity will be improved, the yield strength of the alloy will be greatly reduced and it is impossible to maintain good room temperature comprehensive performance, and it will also have a negative impact on the high temperature performance of the alloy.

[0080] In summary, the Hf-Nb-Zr-V alloy prepared by the preparation method of the present invention not only reduces the alloy constituent elements and reduces the alloy preparation cost, but also makes it easier for the constituent elements to have the same crystal structure. At the same time, on the basis of reducing the number of alloy constituent elements, the alloy still maintains relatively excellent room temperature performance.

[0081] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing a Hf-Nb-Zr-V refractory high entropy alloy, characterized in that: The preparation method comprises the following steps: (1) Weigh the Hf, Nb, Zr and V raw materials according to the designed ratio; (2) placing Hf and Nb in a copper crucible in the order of lower melting point at the bottom and higher melting point at the top for smelting to obtain a Hf-Nb pre-alloyed ingot; (3) placing Zr and V in a copper crucible in the order of lower melting point at the bottom and higher melting point at the top for smelting to obtain a Zr-V pre-alloy ingot; (4) placing the Hf-Nb pre-alloyed ingot in step (2) and the Zr-V pre-alloyed ingot in step (3) into the same crucible, and smelting them in an argon environment to obtain a Hf-Nb-Zr-V refractory high entropy alloy.

2. The method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to claim 1, characterized in that: In the raw materials, the purity of Hf, Nb, Zr and V is all above 99.5wt%.

3. The method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to claim 1, characterized in that: Among the raw materials, Hf, Zr and V are cylindrical particles, and Nb is flaky particles.

4. The method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to claim 1, characterized in that: In the steps (2) and (3), the melting is reversed for no less than 2 times.

5. The method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to claim 1, characterized in that: In the step (4), the pre-alloyed ingot is smelted at least 15 times.

6. The method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to claim 1, characterized in that: In the steps (2), (3) and (4), a vacuum arc furnace is used for arc melting, and the vacuum degree is 1×10 -4 ~5×10 -4 Pa, filled with high purity argon gas to 0.03 ~ 0.05MPa.

7. The Hf-Nb-Zr-V refractory high entropy alloy prepared by the method for preparing a Hf-Nb-Zr-V refractory high entropy alloy according to any one of claims 1 to 6, characterized in that: In the alloy, the atomic ratio of each constituent element is Hf:Nb:Zr:V=1:1:1:

1.

8. The Hf-Nb-Zr-V refractory high entropy alloy according to claim 7, characterized in that: In the alloy, each constituent element has the same crystal structure.

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