MoNbVTi-Zr / Cr refractory high-entropy alloy and preparation method thereof

Abstract

The invention provides a MoNbVTi-Zr / Cr series refractory high-entropy alloy and a preparation method thereof.The preparation method comprises the following steps that Zr or Cr, Nb, Ti, V and Mo are taken and put into a copper crucible of a vacuum arc melting furnace; after the vacuum arc melting furnace reaches a high vacuum state, inert gas is introduced, and then mixed metal is smelted; and after smelting is finished, cooling is conducted, vacuum heat treatment is conducted on the smelted alloy, cooling is conducted, and the refractory high-entropy alloy is obtained. The refractory high-entropy alloy prepared through the method is a BCC solid solution phase and is high in microhardness, the average hardness of nanoindentation is superior to that of most traditional nuclear high-temperature alloy and novel medium-entropy alloy, the compressive strength at the room temperature is high, the compressive strength of the refractory high-entropy alloy is still kept at a high level at the high temperature of 1000 DEG C, and the refractory high-entropy alloy has certain room-temperature plasticity and excellent high-temperature mechanical property; the scheme is simple and easy to operate and high in practicability.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to a MoNbVTi-Zr / Cr refractory high-entropy alloy and its preparation method. Background Technology

[0002] Components in aerospace, nuclear reactors, and ground-based gas turbines face increasingly demanding high-temperature operating conditions. High-temperature alloys have long been the commonly used materials for these environments, but with increasing application requirements, their high-temperature mechanical properties have become increasingly inadequate. In recent years, researchers have begun to focus on multi-principal element alloys with equiatomic or near-equiatomic ratios. In particular, refractory high-entropy alloys with refractory metals such as tungsten (W), molybdenum (Mo), vanadium (V), tantalum (Ta), hafnium (Hf), rhenium (Re), niobium (Nb), chromium (Cr), zirconium (Zr), and titanium (Ti) as main components have brought new possibilities to this field. In 2010, the Senkov research group at the U.S. Air Force Research Laboratory developed two typical refractory high-entropy alloys—NbMoTaW and NbMoTaWV. Their mechanical performance at 800 °C is significantly better than traditional high-temperature alloys, and their yield strength remains above 400 MPa at 1600 °C. Subsequently, in order to achieve goals such as reducing density, improving room temperature compressive strength and plasticity, and improving overall high-temperature performance, a variety of new alloys such as HfNbTaTiZr, MoNbNiTaTi, and TaHfMoNbTi have emerged.

[0003] However, classic NbMoTaW alloys exhibit low plasticity at room temperature, with a fracture strain of only 2.6%, demonstrating significant brittleness. This poses difficulties for machining and limits their practical engineering applications. To improve their room temperature toughness, researchers have attempted to adjust these elements by adding or replacing zirconium (Zr), chromium (Cr), titanium (Ti), nickel (Ni), and aluminum (Al), but these adjustments often lead to a decrease in both room temperature hardness and high-temperature mechanical properties. To address this issue, this invention proposes a MoNbVTi-Zr / Cr refractory high-entropy alloy and its preparation method, aiming to overcome the existing challenge of balancing room temperature plasticity and high-temperature performance. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a MoNbVTi-Zr / Cr refractory high-entropy alloy and its preparation method.

[0005] The present invention adopts the following technical solution: (I) This invention provides a method for preparing a MoNbVTi-Zr / Cr refractory high-entropy alloy, comprising the following steps: taking Zr or Cr, as well as Nb, Ti, V and Mo, and placing them in a copper crucible of a vacuum arc melting furnace; after the vacuum arc melting furnace reaches a high vacuum state, introducing an inert gas, and then melting the mixed metal; cooling after melting, performing vacuum heat treatment on the molten alloy, and cooling to obtain a refractory high-entropy alloy.

[0006] Furthermore, the Zr or Cr, as well as Nb, Ti, V and Mo, are placed into the copper crucible of the vacuum arc melting furnace in order of increasing melting point.

[0007] Furthermore, the atomic molar ratio of Mo, V, Nb, Ti to Zr / Cr is 0.25~0.5:0.5~1.0:0.5~1.0:1.0:0~1.0.

[0008] Furthermore, the inert gas is argon with a purity of 99.99%.

[0009] Furthermore, the process of melting the mixed metal is as follows: increase the current until the metal alloy can be completely melted, the melting time of the alloy is 4 to 6 minutes, after the alloy has completely cooled, the ingot is flipped over by a robotic arm and melted again for 4 to 6 minutes, and the same steps are used to continue melting, repeating 8 to 12 times.

[0010] Furthermore, the process of melting the mixed metal is as follows: increase the current until the metal alloy can be completely melted, the melting time of the alloy is 5 minutes, after the alloy is completely cooled, the ingot is flipped by a robotic arm and melted again for 5 minutes, and the same steps are used to continue melting, repeating 10 times.

[0011] Furthermore, during the smelting process of the mixed metal, magnetic stirring is performed in all smelting processes except for the first and last smelting.

[0012] Furthermore, after the melting process is completed, the cooling time is 15-30 minutes. After complete cooling, the furnace door is opened, and the sample is removed. Furthermore, the vacuum degree of the vacuum heat treatment is 10~100 Pa, the temperature is 1000~1200 ℃, and the holding time is 10~15h; after being taken out of the furnace, it is cooled by oil, water or air.

[0013] (ii) The present invention also provides a MoNbVTi-Zr / Cr refractory high entropy alloy prepared by the above preparation method, wherein the atomic molar ratio of Mo, V, Nb and Ti to Zr / Cr is: 0.25~0.5:0.5~1.0:0.5~1.0:1.0:0~1.0, and the as-cast microstructure is columnar crystal or dendritic structure.

[0014] The beneficial effects of this invention are: (1) The refractory high entropy alloy prepared by the method of the present invention is a BCC solid solution phase, and no impurity phases such as intermetallic compounds or oxides were found.

[0015] (2) The refractory high-entropy alloy prepared by the method of the present invention has high microhardness, which is significantly higher than that of traditional nuclear zirconium alloys and austenitic stainless steel. The average hardness of the nanoindentation is better than that of most traditional nuclear high-temperature alloys and medium-entropy alloys.

[0016] (3) The refractory high entropy alloy prepared by the method of the present invention has high room temperature compressive strength, and its compressive strength (compression deformation of 50%) and tensile strength remain at a high temperature of 1000 °C, thus possessing both excellent room temperature plasticity and high temperature mechanical properties. Attached Figure Description

[0017] Figure 1 These are the XRD patterns of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 The XRD patterns are shown in Figure b, which is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The XRD pattern of Mo prepared in Example 2, c is the XRD pattern of Mo prepared in Example 2. 0.5 VNbTiCr 0.25 XRD patterns; Figure 2 These are the OM diagrams of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 OM diagram, b is TiZrMo prepared in Example 3 0.25 V 0.5 Nb 0.5 The OM diagram, c is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 OM diagram; Figure 3 These are the nanoindentation load and displacement curves of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5NbTiZr 0.25 The nanoindentation test load versus displacement curves are shown in Figure b, which is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The nanoindentation test load versus displacement curves, where c is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 The load-displacement curves of nanoindentation tests; Figure 4 These are nanoindentation test images of the refractory high-entropy alloys prepared in Examples 1-3; where a is the elastic modulus and b is the nanohardness. Figure 5 These are the room temperature (25 °C) compressive strength test results of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 The compressive strength results are shown in Figure b, where b is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 The compressive strength results are shown in the figure. c is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The compressive strength results are shown in the figure. Figure 6 The graph shows the test results of the compressive strength of the refractory high-entropy alloys prepared in Examples 1-3 at high temperatures (600 ℃, 800 ℃ and 1000 ℃); Figure 7 These are the tensile strength test results of the refractory high-entropy alloys prepared in Examples 1-3 at room temperature (25 °C); Figure 8 The figures show the tensile strength test results of the refractory high-entropy alloys prepared in Examples 1-3 at high temperatures (600 ℃, 800 ℃ and 1000 ℃). Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 This embodiment provides a method for preparing a MoNbVTiZr-based refractory high-entropy alloy, including the following steps: (1) Weigh out five refractory metals: Mo, V, Nb, Ti, and Zr. The molar ratio of the atomic numbers of Mo, V, Nb, Ti, and Zr is 0.5:0.5:1.0:1.0:0.25. Weigh the materials according to the above ratio and place them into the copper crucible of the vacuum arc melting furnace in order of melting point from low to high. Then close the furnace door.

[0020] (2) After the vacuum arc melting furnace reaches a high vacuum state, high-purity Ar gas with a purity of 99.99% is introduced as a protective gas. (3) Melt the mixed metals by increasing the current until the metal alloy can be completely melted. The melting time of the alloy is 5 minutes. After the alloy is completely cooled, the ingot is flipped by the robotic arm and melted again for 5 minutes. The same steps are used to continue melting, and this is repeated 10 times. Except for the first and last melting, magnetic stirring is performed in all other melting processes to ensure uniform melting.

[0021] (4) After the melting is completed, wait 20 minutes until it is completely cooled before opening the furnace door and taking out the sample.

[0022] (5) The smelted alloy is subjected to vacuum heat treatment. The vacuum degree of the vacuum heat treatment is 10~100 Pa, the temperature is 1000~1200 ℃, and the holding time is 15 h. After being taken out of the furnace, it is air-cooled to obtain the refractory high-entropy alloy Mo. 0.5 V 0.5 NbTiZr 0.25 .

[0023] Example 2 This embodiment provides a method for preparing a MoNbVTiCr refractory high-entropy alloy, including the following steps: (1) Weigh out five refractory metals: Mo, V, Nb, Ti, and Cr. The atomic molar ratio of Mo, V, Nb, Ti, and Cr is 0.5:1.0:1.0:1.0:0.25. Weigh the materials according to the above ratio and place them into the copper crucible of the vacuum arc melting furnace in order of melting point from low to high. Then close the furnace door.

[0024] (2) After the vacuum arc melting furnace reaches a high vacuum state, high-purity Ar gas with a purity of 99.99% is introduced as a protective gas. (3) Melt the mixed metals by increasing the current until the metal alloy can be completely melted. The melting time of the alloy is 5 minutes. After the alloy is completely cooled, the ingot is flipped by the robotic arm and melted again for 5 minutes. The same steps are used to continue melting, and this is repeated 10 times. Except for the first and last melting, magnetic stirring is performed in all other melting processes to ensure uniform melting.

[0025] (4) After the melting is completed, wait 20 minutes until it is completely cooled before opening the furnace door and taking out the sample.

[0026] (5) The smelted alloy is subjected to vacuum heat treatment. The vacuum degree of the vacuum heat treatment is 10~100 Pa, the temperature is 1000~1200 ℃, and the holding time is 15 h. After being taken out of the furnace, it is air-cooled to obtain the refractory high-entropy alloy Mo. 0.5 VNbTiCr 0.25 .

[0027] Example 3 This embodiment provides a method for preparing a MoNbVTiZr-based refractory high-entropy alloy, including the following steps: (1) Weigh out five refractory metals: Mo, V, Nb, Ti, and Zr. The molar ratio of the atomic numbers of Mo, V, Nb, Ti, and Zr is 0.25:0.5:0.5:1.0:1.0. Weigh the materials according to the above ratio and place them into the copper crucible of the vacuum arc melting furnace in order of melting point from low to high. Then close the furnace door.

[0028] (2) After the vacuum arc melting furnace reaches a high vacuum state, high-purity Ar gas with a purity of 99.99% is introduced as a protective gas. (3) Melt the mixed metals by increasing the current until the metal alloy can be completely melted. The melting time of the alloy is 5 minutes. After the alloy is completely cooled, the ingot is flipped by the robotic arm and melted again for 5 minutes. The same steps are used to continue melting, and this is repeated 10 times. Except for the first and last melting, magnetic stirring is performed in all other melting processes to ensure uniform melting.

[0029] (4) After the melting is completed, wait 20 minutes until it is completely cooled before opening the furnace door and taking out the sample.

[0030] (5) The smelted alloy is subjected to vacuum heat treatment. The vacuum degree of the vacuum heat treatment is 10~100 Pa, the temperature is 1000~1200 ℃, and the holding time is 15 h. After being taken out of the furnace, it is air-cooled to obtain the refractory high entropy alloy TiZrV. 0.5 Mo 0.25 Nb 0.5 .

[0031] Effect test The refractory high-entropy alloys prepared in Examples 1-3 were characterized and their mechanical properties were tested at room temperature and high temperature.

[0032] Table 1 shows the microhardness of the refractory high-entropy alloys prepared in Examples 1-3. Ten points were evenly distributed on each sample to test the microhardness, and the average value was taken as the sample's microhardness. Table 2 shows the compressive strength of the refractory high-entropy alloys prepared in Examples 1-3 at 600 ℃, 800 ℃, and 1000 ℃ (HB 7571-1997). Table 3 shows the room temperature compressive strength of the refractory high-entropy alloys prepared in Examples 1-3 (GB / T 7314-2017). Table 4 shows the room temperature tensile strength of the refractory high-entropy alloys prepared in Examples 1-3 (GB / T 228.1-2021). Table 5 shows the tensile strength of the refractory high-entropy alloys prepared in Examples 1-3 at 600 ℃, 800 ℃, and 1000 ℃ (GB / T 228.2-2015).

[0033] Figure 1 These are the XRD patterns of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 The XRD patterns are shown in Figure b, which is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The XRD pattern of Mo prepared in Example 2, c is the XRD pattern of Mo prepared in Example 2. 0.5 VNbTiCr 0.25 XRD patterns. Figure 1 The sample showed a typical BCC structure, indicating that the refractory high-entropy alloy formed a single-phase solid solution.

[0034] Figure 2 These are the OM diagrams of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 OM diagram, b is TiZrMo prepared in Example 3 0.25 V 0.5 Nb 0.5 The OM diagram, c is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 OM diagram. Figure 2 Show Mo 0.5 V 0.5 NbTiZr 0.25 and Mo 0.5 VNbTiCr 0.25 TiZrMo exhibits oriented columnar dendrites. 0.25 V 0.5 Nb 0.5 It exhibits equiaxed dendrites.

[0035] Figure 3These are the nanoindentation load and displacement curves of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 The nanoindentation test load versus displacement curves are shown in Figure b, which is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The nanoindentation test load versus displacement curves, where c is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 The load-displacement curves of nanoindentation tests. Figure 4 These are nanoindentation test images of the refractory high-entropy alloys prepared in Examples 1-3; where a is the elastic modulus and b is the nanohardness. Figure 3 and Figure 4 It can be seen that Mo 0.5 V 0.5 NbTiZr 0.25 and TiZrMo 0.25 V 0.5 Nb 0.5 Average elastic modulus ≥120 GPa, Mo 0.5 VNbTiCr 0.25 Its average elastic modulus can reach 153 GPa, surpassing most traditional high-temperature alloys and refractory high-entropy alloys.

[0036] Figure 5 These are the room temperature (25 °C) compressive strength test results of the refractory high-entropy alloys prepared in Examples 1-3; where a is the Mo prepared in Example 1. 0.5 V 0.5 NbTiZr 0.25 The compressive strength results are shown in Figure b, where b is the Mo prepared in Example 2. 0.5 VNbTiCr 0.25 The compressive strength results are shown in the figure. c is the TiZrMo prepared in Example 3. 0.25 V 0.5 Nb 0.5 The compressive strength results are shown in the figure. (From...) Figure 5 It can be seen that Mo 0.5 V 0.5 NbTiZr 0.25 The alloy can achieve a very high level of tensile strength, while the other two alloys eventually show a decrease in stress level with increasing strain, but still remain at a high level.

[0037] Figure 6 The graphs show the compressive strength test results of the refractory high-entropy alloys prepared in Examples 1-3 at high temperatures (600 ℃, 800 ℃, and 1000 ℃). Figure 6It can be seen that the compressive strength of the refractory high-entropy alloy at 600 ℃, 800 ℃ and 1000 ℃ is similar to that of the TiZrMo alloy. 0.25 V 0.5 Nb 0.5 The stress-strain curves of the sample showed no yield plateau at any of the three temperatures, indicating direct brittle fracture. The stress-strain test curves of the other two chemical compositions showed similar trends.

[0038] Figure 7 These are the tensile strength test results at room temperature (25 °C) for the refractory high-entropy alloys prepared in Examples 1-3. Figure 7 It can be seen that all three chemical composition samples exhibited direct brittle fracture.

[0039] Figure 8 The graphs show the tensile strength test results of the refractory high-entropy alloys prepared in Examples 1-3 at high temperatures (600 ℃, 800 ℃, and 1000 ℃). Figure 8 It can be seen that all three chemical composition samples exhibited direct brittle fracture at high temperatures.

[0040] Table 1 Microhardness (HV) of Refractory High Entropy Alloys

[0041] Table 2 Compressive strength of refractory high-entropy alloys at 600 ℃, 800 ℃ and 1000 ℃ (HB 7571-1997)

[0042] Table 3. Room temperature compressive strength of refractory high-entropy alloys (GB / T 7314-2017)

[0043] Table 4. Room temperature tensile strength of refractory high-entropy alloys (GB / T 228.1-2021)

[0044] Table 5 Tensile strength of refractory high-entropy alloys at 600 ℃, 800 ℃ and 1000 ℃ (GB / T 228.2-2015)

[0045] The above results indicate that the refractory high-entropy alloy Mo prepared in Example 1... 0.5 V 0.5 NbTiZr 0.25The alloy exhibits a single BCC structure with a typical dendritic microstructure and a microhardness of 375.4 HV. Nanoindentation testing revealed an average hardness of 5.646 GPa and an average elastic modulus of 121.038 GPa. Compression and tensile mechanical property tests on this refractory high-entropy alloy showed excellent performance: a room temperature compressive strength of 7650 MPa; and compressive strengths at 600 ℃, 800 ℃, and 1000 ℃ of 2063 MPa, 798 MPa, and 365 MPa, respectively, demonstrating excellent high-temperature compressive mechanical properties, although the compressive strength decreased with increasing temperature. Its room temperature tensile strength was 108 MPa (elongation after fracture 0.5%), and with temperatures reaching 600 ℃, 800 ℃, and 1000 ℃, the tensile strengths reached 152 MPa, 132 MPa, and 101 MPa, respectively, indicating good high-temperature tensile strength.

[0046] Example 2: Refractory high-entropy alloy Mo prepared 0.5 VNbTiCr 0.25 It exhibits a single BCC structure with a typical columnar dendrite microstructure; its microhardness reaches 387.1 HV. Nanoindentation testing shows that the alloy has an average hardness of 6.709 GPa and an average elastic modulus of 152.662 GPa. Compression and tensile mechanical property tests were conducted on this refractory high-entropy alloy: its room temperature compressive strength reaches a high strength of 1783 MPa, demonstrating excellent performance; its compressive strength at 600 ℃, 800 ℃, and 1000 ℃ reaches 1392 MPa, 814 MPa, and 430 MPa, respectively, showing excellent high-temperature compressive mechanical properties, but the compressive strength decreases with increasing temperature. Its room temperature tensile strength is 93 MPa (elongation after fracture 0.5%), and with temperatures reaching 600 ℃, 800 ℃, and 1000 ℃, its tensile strength reaches 156 MPa, 177 MPa, and 0 MPa, respectively.

[0047] Refractory high-entropy alloy TiZrMo prepared in Example 3 0.25 V 0.5 Nb 0.5The alloy exhibits a single BCC structure with an equiaxed dendritic microstructure and a microhardness of 416.9 HV. Nanoindentation testing revealed an average hardness of 6.951 GPa and an average elastic modulus of 124.977 GPa. Compressive and tensile mechanical property tests on this refractory high-entropy alloy showed excellent room-temperature compressive strength of 2518 MPa. Its compressive strengths at 600 ℃, 800 ℃, and 1000 ℃ reached 1362 MPa, 332 MPa, and 284 MPa, respectively, while its high-temperature compressive and tensile mechanical properties decreased sharply at 800 ℃. However, its room-temperature tensile strength was 88 MPa (elongation after fracture 0.5%), and with temperatures reaching 600 ℃, 800 ℃, and 1000 ℃, its tensile strength decreased to 178 MPa, 0 MPa, and 38 MPa, respectively, indicating that both its high-temperature compressive and tensile strengths decreased with increasing temperature.

[0048] This invention utilizes vacuum arc melting technology to prepare MoNbVTi-Zr / Cr refractory high-entropy alloys. The as-cast microstructure is entirely dendritic. These refractory high-entropy alloys exhibit excellent mechanical properties, with a microhardness reaching 400 HV, significantly higher than traditional nuclear-grade zirconium alloys and austenitic stainless steels. The maximum compressive strength at room temperature is 2518~7650 MPa; the maximum compressive strength at 600 °C (50% compression set) is 2063 MPa; the maximum compressive strength at 800 °C (50% compression set) is 814 MPa; and the maximum compressive strength at 1000 °C (50% compression set) is 430 MPa. The maximum tensile strength at room temperature (0.5% elongation after fracture) is 108 MPa; the maximum tensile strength at 600 °C is 178 MPa; and the maximum tensile strength at 1000 °C is 101 MPa.

[0049] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a MoNbVTi-Zr / Cr refractory high-entropy alloy, characterized in that, Includes the following steps: Take Zr or Cr, along with Nb, Ti, V and Mo, and place them into a copper crucible in a vacuum arc melting furnace; After the vacuum arc melting furnace reaches a high vacuum state, an inert gas is introduced, and then the mixed metals are melted. After melting and cooling, the molten alloy is subjected to vacuum heat treatment and then cooled to obtain a refractory high-entropy alloy.

2. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, The Zr or Cr, along with Nb, Ti, V, and Mo, are placed into the copper crucible of the vacuum arc melting furnace in order of increasing melting point.

3. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, The atomic molar ratio of Mo, V, Nb, Ti to Zr / Cr is 0.25~0.5:0.5~1.0:0.5~1.0:1.0:0~1.

0.

4. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, The inert gas is argon with a purity of 99.99%.

5. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, The process of smelting the mixed metal is as follows: Increase the current until the metal alloy can be completely melted. The melting time for each alloy is 4 to 6 minutes. After the alloy has completely cooled, use a robotic arm to flip the ingot and melt it again for 4 to 6 minutes. Continue melting using the same steps, repeating 8 to 12 times.

6. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, During the smelting of the mixed metal, magnetic stirring is performed in all smelting processes except for the first and last smelting.

7. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, After the melting process is completed, the cooling time is 15-30 minutes.

8. The method for preparing the MoNbVTi-Zr / Cr refractory high-entropy alloy according to claim 1, characterized in that, The vacuum heat treatment has a vacuum level of 10~100 Pa, a temperature of 1000~1200 ℃, and a holding time of 10~15 h.

9. A MoNbVTi-Zr / Cr refractory high-entropy alloy prepared by the preparation method according to any one of claims 1 to 8.

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