A co cr fe ni high-entropy alloy and a preparation method thereof

Abstract

The application belongs to the technical field of high-entropy alloys, and particularly relates to a CoCrFeNi high-entropy alloy and a preparation method thereof. 100‑x‑y Nb x Al y , x is the atomic percentage of Nb, y is the atomic percentage of Al, x+y=11-13; the high-entropy alloy at least comprises an FCC phase and a Laves phase. The preparation method comprises the following steps: weighing and pretreating metal raw materials; placing an oxygen absorption carrier in a central crucible, and placing raw materials in a main smelting crucible according to the melting points of the elements in the alloy from low to high from bottom to top; vacuumizing and gas-filling to establish an initial protective atmosphere, repeating vacuumizing and gas-filling at least three times to build a micro-negative-pressure protective atmosphere smelting environment; and preparing the CoCrFeNi high-entropy alloy by a vacuum arc smelting method. The CoCrFeNi high-entropy alloy with specific doping elements and doping ratios is screened out, and the demand for high strength and high plasticity coordination is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-entropy alloys, and particularly relates to a CoCrFeNi high-entropy alloy and a preparation method thereof. BACKGROUND

[0002] A high-entropy alloy is a new material system that breaks through the traditional alloy design concept, and its core feature is that five or more main elements are composed of equal atomic ratio or near equal atomic ratio. This unique multi-component design triggers four core effects that are significantly different from traditional alloys: high-entropy effect, lattice distortion effect, slow diffusion effect and "cocktail" effect. Thanks to these effects, high-entropy alloys generally exhibit excellent strength-plasticity balance, excellent corrosion resistance and good high-temperature stability. These outstanding comprehensive properties make its application in aerospace, nuclear power equipment, biomedical materials and various extreme environments show an extremely attractive prospect.

[0003] Among many high-entropy alloy systems, the CoCrFeNi alloy with face-centered cubic crystal structure becomes a representative system because of its excellent room temperature plasticity (such as fracture elongation usually > 50%), excellent low temperature toughness and significant work hardening capacity. However, the single FCC phase CoCrFeNi alloy has low yield strength, which is difficult to meet the demand of high strength and high plasticity coordination of engineering structural materials. SUMMARY

[0004] In view of this, the application aims to provide a CoCrFeNi high-entropy alloy and a preparation method thereof, and at least one technical problem in the background art is solved.

[0005] The application is realized in the following manner:

[0006] The application provides a CoCrFeNi high-entropy alloy in a first aspect, and its chemical composition expression is (CoCrFeNi) 100-x-y Nb x Al y wherein x is the atomic percentage of Nb, y is the atomic percentage of Al, and x+y = 11-13.

[0007] The high-entropy alloy comprises at least an FCC phase and a Laves phase.

[0008] Preferably, the (CoCrFeNi) 100-x-y Nb x Al y wherein x+y = 12.

[0009] Preferably, the (CoCrFeNi) 100-x-y Nb x Al yIn the high-entropy alloy, x = 2-8, and y = 4-10.

[0010] Preferably, the (CoCrFeNi) 100-x-y Nb x Al y In the high-entropy alloy, x = 2, and y = 10; a three-phase eutectic structure of FCC phase, BCC phase and Laves phase is formed.

[0011] Preferably, the (CoCrFeNi) 100-x-y Nb x Al y In the high-entropy alloy, x = 8, and y = 4; a two-phase coherent structure of FCC phase and Laves phase is formed.

[0012] The second aspect of the present application provides a preparation method of the above-mentioned CoCrFeNi-based high-entropy alloy, which comprises the following steps:

[0013] According to the preset atomic percentage requirement, Al, Co, Cr, Fe, Ni and Nb metal raw materials are weighed and pretreated for impurity removal;

[0014] A high-entropy alloy oxygen absorption carrier is placed in the center crucible of a vacuum melting device, and the raw materials are sequentially placed in the main melting crucible from low to high according to the melting points of the elements in the raw materials, and the main melting crucible is arranged around the center crucible;

[0015] The vacuum melting device is vacuumed and gassed to establish an initial protective atmosphere, and the vacuuming and gassing are repeated at least three times to build a micro-negative pressure protective atmosphere melting environment;

[0016] The CoCrFeNi-based high-entropy alloy is prepared based on the vacuum arc melting method.

[0017] Preferably, the current of the vacuum arc melting is 160A-220A;

[0018] Preferably, during the vacuum arc melting, the oxygen absorption carrier is subjected to at least 3 cycles of pulse melting, and then the raw materials are subjected to at least 4 continuous melting.

[0019] Preferably, during the vacuum arc melting, when the raw materials are completely melted and in liquid state, a 0.4T-0.6T alternating magnetic field is used for magnetic stirring to realize uniform mixing of the raw materials; the magnetic stirring is coupled with the continuous melting process.

[0020] Preferably, the oxygen absorption carrier uses a Ti ingot.

[0021] Compared with the prior art, the present application screens out a CoCrFeNi-based high-entropy alloy with specific doping elements and doping ratios, which meets the demand for high strength and high plasticity synergy.

[0022] The present application constructs a dual-phase coherent structure including at least the FCC phase and the Laves phase, or even a triple-phase eutectic structure of the FCC phase, the BCC phase and the Laves phase, plays a fine-grain strengthening effect, and significantly improves the comprehensive mechanical properties of the material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 XRD comparison chart of the NA2-10 alloy in the embodiment 1 of the present application and the comparative examples NA0-12 alloy and NA0-0 alloy;

[0024] Figure 2 Scanning electron microscope chart of the NA2-10 alloy in the embodiment 1 of the present application and the comparative examples NA0-0 alloy and NA0-12 alloy;

[0025] Figure 3 Compression performance curve of the NA2-10 alloy in the embodiment 1 of the present application and the comparative example NA0-0 alloy;

[0026] Figure 4 Microstructure chart of a high-entropy alloy with the same elements as the present application in the prior art;

[0027] Figure 5 Microstructure chart of a high-entropy alloy with similar elements as the present application in the prior art;

[0028] Figure 6 XRD comparison chart of the NA8-4 alloy in the embodiment 2 of the present application and the comparative examples NA4-8 alloy, NA6-6 alloy and NA10-2 alloy;

[0029] Figure 7 Scanning electron microscope chart of the NA8-4 alloy in the embodiment 2 of the present application and the comparative examples NA4-8 alloy, NA6-6 alloy and NA10-2 alloy;

[0030] Figure 8 Figure 7 Enlarged chart of the eutectic structure of the NA8-4 alloy in the embodiment 2 of the present application and the comparative examples NA4-8 alloy, NA6-6 alloy and NA10-2 alloy;

[0031] Figure 9 Compression curve chart of the NA8-4 alloy in the embodiment 2 of the present application and the comparative examples NA4-8 alloy, NA6-6 alloy, NA10-2 alloy and NA12-0 alloy;

[0032] Figure 10 Bright field image of the eutectic zone of the NA8-4 alloy in the embodiment 2 of the present application;

[0033] Figure 11 ​The bi-phase diffraction spot diagram and its inverse Fourier transform to obtain the lattice fringe diagram of the NA8-4 alloy in Example 2 of the present application;

[0034] Figure 12 The transmission electron microscope diagram of the interface between the FCC phase and the Laves phase in the prior art high-entropy alloy. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with examples. It should be understood that the specific implementation cases described herein are only used to explain the present application and do not limit the present application.

[0036] The corresponding CoCrFeNi high-entropy alloy is prepared by a melting method, and is named according to the corresponding mode in Table 1.

[0037] The preparation method of the CoCrFeNi high-entropy alloy comprises the following steps:

[0038] S1, according to the preset atomic percentage requirement, the Al, Co, Cr, Fe, Ni and Nb metal raw materials (purity ≥ 99.95%) are weighed, 240 mesh abrasive belt is used for rotary surface grinding, and then gradient ultrasonic cleaning (40 kHz / 5 min→28 kHz / 5 min) is carried out in anhydrous ethanol solution; after cleaning, the surface is dehydrated and stored in a vacuum bag containing molecular sieves;

[0039] S2, the high-entropy alloy oxygen absorption carrier (Ti ingot) is placed in the center crucible of the vacuum melting equipment, and the raw materials are placed in the main melting crucible from low to high according to the melting point of each element in the raw material (Al→Cr→Fe→Co→Ni→Nb) from bottom to top; the main melting crucible is arranged around the center crucible;

[0040] S3, the mechanical pump is started to pre-extract the melting chamber to below 50 Pa, then argon is injected into the melting chamber to establish an initial protective atmosphere; then the molecular pump is used for secondary vacuum extraction to below 50 Pa, and Ar gas is introduced in a gradient to a micro-negative pressure state (-0.03 to -0.07 kPa); after repeated pumping and charging three times, the mechanical pump is closed to prepare for melting;

[0041] S4, the CoCrFeNi high-entropy alloy is prepared based on the vacuum arc melting method; during the melting process, after controlling the gap between the electrode and the raw material to be about 3 mm, the arc is started to begin melting; according to the current fluctuation characteristics, a 10 ms level response adjustment is carried out in the interval of 160 A-220 A (200 A is used in the following examples); when the raw material ingot is completely melted and in a liquid state, about 0.5T alternating magnetic field is used for magnetic stirring to make the ingot mix uniformly; first, pulse melting of the oxygen absorption carrier is completed (3 cycles), and then 5 times of continuous melting and synchronous coupling of magnetic field stirring are carried out.

[0042] Specifically, the chemical composition expression of the high-entropy alloy is (CoCrFeNi) 100-x-y Nb x Al y wherein x is the atomic percentage of Nb, y is the atomic percentage of Al, x+y = 11-13 (preferably 12); the high-entropy alloy comprises at least a coherent structure of FCC phase and Laves phase.

[0043] Preferably, x = 2-8, y = 4-10. More preferably, x = 2, y = 10, a three-phase eutectic structure of FCC phase, BCC phase and Laves phase is formed in the high-entropy alloy; or, x = 8, y = 4, a two-phase coherent structure of FCC phase and Laves phase is formed in the high-entropy alloy.

[0044] Table 1

[0045]

[0046] Example 1

[0047] This embodiment is a high-entropy alloy (CoCrFeNi) 88 Nb2Al 10 .

[0048] Figure 1 XRD patterns of NA2-10 alloy, NA0-12 alloy and NA0-0 alloy are shown. Figure 1 As can be seen from the XRD patterns, the NA0-0 alloy has three strong peaks at [44.3°], [51.5°] and [74.1°], which are basically consistent with the diffraction peak positions of Ni (PDF#: 00-001-1258), indicating that the NA0-0 alloy has a single FCC crystal structure. In addition to the FCC diffraction peak, the NA0-12 alloy also has a BCC diffraction peak. In addition to the FCC crystal structure, the NA2-10 alloy also has characteristic peaks of hexagonal C14 type Laves phase, which are basically consistent with the diffraction peak positions of Fe2Nb (PDF#: 03-065-3574). This indicates that the Laves phase in the alloy is the second phase generated.

[0049] Figure 2 Scanning electron microscope images of NA0-0 alloy, NA2-10 alloy and NA0-12 alloy are shown, and the point scanning results of each region are listed in Table 2. Figure 2 As shown in (a) of the figure, the alloy has a single-phase structure. Figure 2 As can be seen from (a) of the figure, the alloy has a single-phase structure. Figure 2 As can be seen from (a) of the figure, the alloy has a single-phase structure. Figure 2 According to the XRD results, it is known that the alloy has an FCC crystal structure. Figure 2Image (b) is a scanning electron microscope (SEM) image of the NA2-10 alloy. With the introduction of Nb and Al, the solidification path of the alloy changes significantly, and the microstructure of Nb2-Al10 exhibits a three-phase coexistence. Combined with the spot scan results in Table 2, it can be seen that the light gray matrix A is rich in Co / Cr / Ni / Fe elements. Since the CoCrFeNi high-entropy alloy has a single-phase FCC crystal structure, combined with... Figure 2 XRD results show that the light gray matrix has an FCC crystal structure. Nb and Al atoms have entered the FCC crystal structure through solid solution. The dark gray secondary phase B has an Al content as high as 10.12%. Based on current technology, Al can promote the formation of the BCC phase; therefore, B can be presumed to be the BCC phase. It should be noted that the BCC phase was not present in... Figure 2 The XRD detection is due to the low content and insensitivity to diffraction. Figure 2 In (c)NA0-12, a point scan of the secondary phase C revealed that it is also rich in Al, and... Figure 2 XRD detected diffraction peaks of the BCC phase. Therefore, it can be basically determined that the dark gray secondary phase of NA2-10 is the BCC phase.

[0050] Local magnification of the eutectic region microstructure of NA2-10 alloy as shown below Figure 2 As shown in (d), it was found to consist of three phases. The point scan results for the three phases are shown in Table 2. Points D and E have compositions similar to the FCC and BCC phases discussed earlier; combined with the XRD results, they are identified as FCC and BCC phases, respectively. Point F in the white area is rich in Nb. Figure 2 The XRD results show that it has a Laves phase crystal structure. This indicates that the BCC phase precipitates preferentially over the Laves phase, while the residual liquid phase reaches the ternary eutectic point due to Nb enrichment and then undergoes a eutectic reaction (L→FCC+BCC+Laves).

[0051] Table 2

[0052]

[0053] Because ternary eutectic alloys possess a fine eutectic structure, this structure effectively hinders dislocation movement. When the metallic material is subjected to external forces, dislocations find it difficult to slide freely within the crystal, thus increasing the material's strength. Furthermore, its microstructure is more complex, with stronger interactions and synergistic effects between the phases. During solidification, the morphology and phase composition of the ternary eutectic become more diverse, allowing each phase to exert its mechanical property advantages in different directions and locations, thereby significantly improving the overall strength of the alloy.

[0054] Figure 3The compression performance curves of NA2-10 and NA0-0 are compared in the graph, and it can be seen from the curves that the compression yield strength of NA2-10 is 506 MPa, and the compression yield strength of NA0-0 is 140 MPa, that is, the yield strength of NA2-10 is 3.6 times that of NA0-0 alloy. In terms of plasticity, NA2-10 also exhibits high plasticity like NA0-0.

[0055] Although the ternary eutectic structure makes the alloy excellent in performance, however, not any high-entropy alloy of composition exists ternary eutectic point, because the composition interval of ternary eutectic point is generally small. And, even if according to the simulation of phase diagram, the composition interval of ternary eutectic point is simulated to exist in part of high-entropy alloy, however, in the actual solidification process, due to the influence of solid solution, the metal atoms in the liquid state will inevitably be solid-solved into the primary phase during cooling, resulting in that the uncooled liquid metal cannot reach the theoretical ternary eutectic composition point, and finally the ternary eutectic structure cannot be obtained.

[0056] In order to further embody the characteristics of the embodiment 1 of the present application, Figure 4 It is shown that several high-entropy alloys of the same elements are exhibited, and it can be obviously seen from the structure that the ternary eutectic structure is not found. Figure 5 For several high-entropy alloys of similar element types, the ternary eutectic structure is also not found. It should be noted that, Figure 4 and Figure 5 Only several prior arts are listed as examples, and actually, in the existing literature, no alloy of related element composition has been found to form a ternary eutectic structure. Therefore, the occurrence of the ternary eutectic structure in the embodiment 1 of the present application is an unexpected technical feature, and also plays an unexpected effect on improving the mechanical properties of the material.

[0057] Embodiment 2

[0058] The embodiment is a high-entropy alloy (CoCrFeNi) 88 Nb8Al4.

[0059] Figure 6 XRD of NA4-8 alloy, NA6-6 alloy, NA8-4 alloy and NA10-2 alloy is shown, and it can be seen from the XRD that Figure 6 In addition to the matrix phase FCC, the second phase (Laves phase) exists in the above several alloys.

[0060] Figure 7 The scanning electron microscope images of NA4-8 alloy, NA6-6 alloy, NA8-4 alloy and NA10-2 alloy are shown in (a)-(d), respectively. Figure 6From the XRD results, only FCC phase and Laves phase exist in all the above alloys. Further, the data of point scanning on the corresponding areas are shown in Table 3. According to the data of point scanning in Table 3, the white structure is Laves phase and the gray structure is FCC phase. Figure 8 (a)-(d) correspond to Figure 7 The enlarged images of eutectic structure of the alloys show that the eutectic regions of the above several alloys are binary eutectic, which is obviously different from the ternary eutectic of Example 1.

[0061] Table 3

[0062]

[0063] Figure 9 The compression curves of the alloys are shown in Figure 4, and the corresponding performance is summarized in Table 4. From Figure 9 it can be seen that the yield strength of NA8-4 is 1231 MPa, which is 8.8 times that of NA0-0. Compared with the other Nb / Al co-doped alloys, NA8-4 has excellent comprehensive mechanical properties. From Figure 9 it can be found that a performance rule, with the increase of the content of Nb, the compression strength of the alloy is basically positively correlated with the content of Nb. However, the plasticity is continuously decreased. It should be noted that the compression strength of NA8-4 alloy is almost the same as that of NA12-0 alloy, but the plasticity is 1.46 times that of NA12-0 alloy.

[0064] Table 4

[0065]

[0066] Figure 10 The bright field image of the eutectic region of NA8-4 is shown in Figure 6. After selected area electron diffraction on the two phases of the eutectic region, the white area is calibrated by Ni (PDF#: 00-001-1258) and the gray area is calibrated by Fe2Nb (PDF#: 03-065-3574), further confirming that the alloy is composed of FCC phase and Laves phase.

[0067] After analyzing the diffraction spots of Figure 10 the two phases, it is found that the (1, 1, 1) crystal plane of the FCC phase and the (2, -1, -1, 0) crystal plane of the Laves phase are parallel, as shown in Figure 11 (a) and (b) of Figure 7, and the red line in (b) is translated from (a). In (b), the red line is completely coincided with the <2, -1, -1, 0> crystal direction. Then the inverse Fourier transform is carried out to obtain the lattice fringes, as shown in Figure 11 (c) and (d) of Figure 8. After measuring the interplanar spacing, it is found that the interplanar spacing of the FCC phase is and the interplanar spacing of the Laves phase is

[0068] According to the degree of mismatch The result is 2.325%. It is generally believed in the art that the degree of mismatch is less than 5%, therefore, according to the calculation result, the FCC phase and the Laves phase of the alloy NA8-4 are coherent, which is also the reason why the comprehensive mechanical properties of the alloy NA8-4 are excellent. Especially compared with the alloy NA12-0, even though the alloy NA12-0 contains a higher amount of Nb, the compressive strength is almost the same as that of the alloy NA8-4.

[0069] It should be noted that the coherence refers to the phenomenon that the lattices of two phases have the same crystallographic orientation at the interface, and part of the atoms are directly arranged continuously on the interface. It is like two pieces of a jigsaw puzzle, whose edge shape and pattern are completely matched at the joint. Generally speaking, the prerequisite for two phases to form coherence is that the lattice constants are similar and the lattice types are the same.

[0070] For high-entropy alloys, the lattice constants of the phases formed by each component of the high-entropy alloy are different, and the lattice constants of the FCC phase and the Laves phase of the present application cannot be inferred from the prior art. In addition, for the FCC phase and the Laves phase, the solid solubility of atoms in their lattices is also different, so their interplanar spacings will also be affected. In view of the above factors, the coherence of the two phases in the alloy NA8-4 is an unexpected effect, and makes the comprehensive mechanical properties of NA8-4 optimal.

[0071] It is generally recognized in the field of materials science that the non-coherent interface formed between the second phase and the matrix will cause significant stress concentration effect and induce crack nucleation, thereby greatly reducing the toughness and fatigue resistance of the material. For example, the σ phase formed by transition metal elements, although this kind of intermediate phase has a wide solid solution range and does not follow strict stoichiometric relationship, but its low-symmetry crystal structure and complex atomic arrangement will seriously hinder the dislocation slip movement. This micro-mechanism directly leads to the decrease of plastic deformation ability of the material and causes significant embrittlement. When the σ phase is formed in the alloy system, the non-coherent interface between the σ phase and the matrix cannot effectively transmit external load, resulting in serious local stress concentration in the interface region, which provides favorable conditions for crack propagation, and finally leads to brittle fracture failure. Typical experimental data show that in the CoCrFeMnNiMo alloy system, the presence of σ phase makes the compressive strain value before material fracture decrease by 19%. Based on this analysis, this is also the reason why the strength of the alloy NA12-0 is almost not improved, and the plasticity is much smaller than that of the alloy NA8-4.

[0072] Specifically, for the NA8-4 alloy, due to the addition of appropriate Nb and Al elements in CoCrFeNi, the (1, 1, 1) crystal plane spacing of the FCC phase in the NA8-4 alloy is almost equal to the (2, -1, 1, 0) crystal plane spacing of the Laves phase, and the phase difference (the mismatch degree is only 2.325%) between the two phases is almost zero, so that the Laves phase and the FCC phase form a coherent interface, which can effectively reduce the pile-up of dislocations at the interface between the two phases and relieve the stress concentration at the interface, and inhibit the propagation of cracks. However, the NA12-0 alloy, which is supposed to have higher compressive strength with higher Nb content, did not achieve the expected compressive strength. This is mainly due to the change in the content and type of doping elements, which changes the crystal plane spacing of the FCC phase and the Laves phase in the alloy and the phase difference between the two phases, so that the two phases cannot form a coherent interface, resulting in serious local stress concentration in the interface region, which provides favorable conditions for crack propagation, and finally causes the NA12-0 alloy to fail prematurely due to brittle fracture.

[0073] As shown in Figure 12 , although the high-entropy alloy system containing FCC phase and Laves phase has been developed in the prior art, there is still no successful case of coherent structure of the two phases. For example, in Figure 12 (a), Guan et al. studied a new W / FeCoCrNi-based in-situ generated high-entropy alloy gradient coating with Laves-FCC dual-phase structure and synergistic friction behavior. The coating prepared by them only formed a semi-coherent interface, and the adaptation rate was 10.5%. In Figure 12 (b), Fan et al. studied the synergistic effect of Nb and Mo alloying on the microstructure and mechanical properties of CoCrFeNi HEA. The results showed that through synergistic alloying, Laves phase was formed in the FCC matrix which was semi-coherent with the matrix. It should be noted that in this high-entropy alloy system, there are few related literatures on the formation of semi-coherent interface, and for the coherent interface in the present invention, no relevant researchers have found in the existing literature. It is worth noting that in the study of adding Nb element alone in the CoCrFeNi base high-entropy alloy (the phase composition of the obtained alloy is the same as that of the present invention, both of which are FCC phase and Laves phase coexisting system), the coherent relationship between the two phases has not been observed. This phenomenon highlights the particularity of the Nb-Al synergistic doping strategy in the present invention. Comparative analysis shows that the present invention embodiment 2 first realizes the FCC / laves coherent structure in the CoCrFeNi high-entropy alloy, which provides important theoretical support for designing new alloy systems with high strength and good plasticity.

[0074] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A CoCrFeNi-based high-entropy alloy, characterized by, The high-entropy alloy has a chemical composition expression of (CoCrFeNi) 100-x-y Nb x Al y wherein x is the atomic percentage of Nb, y is the atomic percentage of Al, x=8, y=4, and a dual-phase coherent structure of FCC phase and Laves phase is formed in the high-entropy alloy.

2. A CoCrFeNi-based high-entropy alloy, characterized by, The chemical composition expression of the high-entropy alloy is (CoCrFeNi) 100-x-y Nb x Al y Wherein, x is the atomic percentage of Nb, y is the atomic percentage of Al, x=2, y=10; the high-entropy alloy forms three-phase eutectic structure of FCC phase, BCC phase and Laves phase.

3. The method for preparing a CoCrFeNi high-entropy alloy according to claim 1 or 2, characterized in that, The preparation method comprises the following steps: According to the preset atomic percentage requirements, Al, Co, Cr, Fe, Ni, Nb metal raw materials are weighed and pretreated for impurity removal; The central crucible of the vacuum melting equipment is placed with an oxygen-absorbing carrier of high-entropy alloy, and the raw materials are sequentially placed in the main melting crucible from low to high according to the melting points of the elements in the alloy; The vacuum melting equipment is vacuumized and gassed to establish an initial protective atmosphere, and the vacuumization and gassing are repeated at least three times to build a micro-negative pressure protective atmosphere melting environment; The CoCrFeNi high-entropy alloy is prepared based on the vacuum arc melting method.

4. The method according to claim 3, wherein the CoCrFeNi-based high-entropy alloy is prepared by the following steps of: The current of the vacuum arc melting is 160A-220A. ​ 5. The method according to claim 3, wherein the CoCrFeNi-based high-entropy alloy is prepared by the following steps of: During the vacuum arc melting, the oxygen-absorbing carrier is first subjected to pulse melting for at least 3 cycles, and then the raw materials are subjected to continuous melting for at least 4 times. ​ 6. The method according to claim 5, wherein the CoCrFeNi-based high-entropy alloy is prepared by the following steps of: During the vacuum arc melting, when the raw materials are completely melted and in a liquid state, magnetic stirring is performed by using an alternating magnetic field of 0.4T-0.6T to realize uniform mixing of the raw materials; the magnetic stirring is synchronously coupled during the continuous melting process. ​ 7. The method according to claim 3, wherein the CoCrFeNi-based high-entropy alloy is prepared by the following steps of: The oxygen-absorbing carrier uses a Ti ingot. ​

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