Co-cr-cu-fe-ni-sn based high-entropy alloy and preparation method thereof

Abstract

This invention belongs to the field of high-entropy alloy technology. Addressing the problem that existing high-entropy alloys are sensitive to process parameters during rapid solidification, imposing stringent requirements on material preparation and characteristic parameter control, this invention proposes a Co-Cr-Cu-Fe-Ni-Sn series high-entropy alloy and its preparation method. By batching Co, Cr, Cu, Fe, Ni, and Sn raw materials and employing a melt-floating rapid solidification method, the process involves melting the master alloy, mounting, vacuuming, heating, and melt undercooling. Furthermore, by modifying the rapid solidification process parameters to promote the formation of the high-entropy phase in the alloy system, the Co-Cr-Cu-Fe-Ni-Sn series high-entropy alloy is finally obtained. This invention simplifies the melting and solidification process of the Co-Cr-Cu-Fe-Ni-Sn series high-entropy alloy, making the preparation process less time-consuming and easier to implement.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy alloy technology, specifically relating to a Co-Cr-Cu-Fe-Ni-Sn system high-entropy alloy and its preparation method. Background Technology

[0002] Traditional alloys are based on a single metallic element (such as iron-based, titanium-based, nickel-based, etc.), with small amounts of other alloying elements added and different production and processing techniques used to obtain alloys with specific properties. In 2004, Yeh and Cantor broke with the traditional alloy design concept and proposed a new alloy design approach—multi-principal-element high-entropy alloys. These alloys are generally composed of five or more principal elements, as seen in the following literature: Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes, JW Yeh, SK Chen, SJ Lin, JY Gan, TSChin, TTShun, CHTsau, SY Chang, Adv. Eng. Mater, 6, 299-303, 2004; and Microstructural development in equiatomic multicomponent alloys, B. Cantor, ITC Chang, P. Knight, AJB Vincent, Mat. Sci. Eng. A, 375-377, 213-218, 2004. High-entropy alloys, with their unparalleled properties compared to traditional alloys, such as high strength, high toughness, good corrosion resistance, wear resistance, and high temperature resistance, have shown broad application prospects in engineering fields.

[0003] Liquid phase separation refers to the phenomenon where a homogeneous mother liquid phase agglomerates under certain conditions, forming two or more distinct liquid phases coexisting. It is directly related to the Gibbs free energy of the system. Although there is a certain degree of solubility between the separated metallic alloying elements, each liquid phase has its own equilibrium vapor pressure, thus the vapor pressures of the two phases are the same. A significant positive deviation of the vapor pressure from Raoult's law often leads to liquid phase separation. To date, liquid phase separation has been observed in various materials, including metals, polymers, and ceramics. For metals, liquid phase separation significantly affects the dendrite growth process in liquid alloys. After liquid phase separation, parameters such as the dendrite growth rate and the spacing between primary and secondary branches in the alloy melt change significantly, thus affecting the final solidification structure, composition distribution, and application performance of the material.

[0004] Co-Cr-Cu-Fe-Ni alloys have a simple FCC structure and are the earliest discovered pentagonal high-entropy alloys. They possess excellent mechanical and magnetic properties, as described in the literature: Influence of non-magnetic Cu on enhancing the low-temperature magnetic properties and Curie temperature of FeCoNiCrCu(x)highentropy alloys, V. Chaudhary, V. Soni, B. Gwalani, R. Ramanujan, R. Banerjee, ScriptaMater, 182, 99-103, 2020. When the supercooling reaches a certain level, liquid-phase separation occurs, significantly altering the tensile properties of the CoCrCuFeNi high entropy alloy. The solidified sample after liquid-phase separation exhibits higher plasticity and lower elastic modulus (see: Liquid-phase separation in undercooled CoCrCuFeNi high entropy alloy, T. Guo, JS Li, ​​J. Wang, Y. Wang, HCKou, SZ Niu, Intermetallics, 86, 110-115, 2017). If the liquid-phase separation process of the alloy melt can be actively controlled, the final solidified structure can exhibit different micromorphologies such as fully dendritic structure, dispersed second-phase distribution, or complete phase separation, thereby expanding the industrial applications of this type of high entropy alloy.

[0005] To better control processes such as liquid phase separation and dendrite growth, this invention attempts to introduce new components into Co-Cr-Cu-Fe-Ni high-entropy alloys, utilizing the "cocktail effect" of multi-principal-element high-entropy alloys. By adding certain elements, the phase composition and microstructure of these alloys can be altered, potentially further improving their application performance. Special methods are required for the synthesis of these new high-entropy alloys to control their solidification microstructure.

[0006] Under conventional solidification conditions, high-entropy alloys exhibit coarse grain sizes in their solidified microstructure, often exhibiting defects such as elemental segregation, microscopic and macroscopic residual stress, cracks, and porosity. Solidification quality significantly impacts subsequent alloy processing, thus substantially affecting the final product's performance. Therefore, controlling the solidification process is crucial for improving the quality and application performance of solidified products. Rapid solidification via melt flotation is an extreme non-equilibrium solidification method that not only avoids various defects generated during conventional solidification but also enables active control of the solidification process for large-volume high-entropy alloys, resulting in microstructures with uniform composition, fine microstructure, and unique phase structures. However, the rapid solidification of high-entropy alloys is highly sensitive to process parameters, imposing stringent requirements on material preparation and characteristic parameter control. Therefore, introducing new components into Co-Cr-Cu-Fe-Ni high-entropy alloys and providing a novel high-entropy alloy and its preparation method is a problem that this invention urgently needs to address. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy and its preparation method. The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy of this invention is composed of Co, Cr, Cu, Fe, Ni and Sn metals, and is prepared by melt flotation technology. The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy prepared by this invention has high hardness.

[0008] The technical concept of this invention is as follows:

[0009] The raw materials Co, Cr, Cu, Fe, Ni, and Sn in this invention are mostly located in the fourth period of the periodic table, in adjacent subgroups. They have similar atomic radii and properties, and some elements form simple alloy structures. Therefore, this invention prepares a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy by batching the above raw materials and employing a rapid solidification method using melt flotation. The process involves melting the master alloy, mounting, vacuuming, heating, and melt undercooling. By modifying the rapid solidification process parameters to promote the formation of the high-entropy phase in the alloy system, the invention ultimately yields a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy.

[0010] The first objective of this invention is to provide a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, comprising the following components by mass percentage:

[0011] Co: 12 to 15%, Cr: 10 to 13%, Cu: 15 to 28%, Fe: 11 to 14%, Ni: 12 to 15%, Sn: 25 to 30%.

[0012] Preferably, the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy provided by the present invention comprises the following components by mass percentage:

[0013] Co: 14.4%, Cr: 12.8%, Cu: 15.6%, Fe: 13.7%, Ni: 14.4%, Sn: 29.1%.

[0014] A second objective of this invention is to provide a method for preparing the aforementioned Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, comprising the following steps:

[0015] S1. Weigh out the Co, Cr, Cu, Fe, Ni and Sn metal raw materials according to their mass percentages, and set aside for later use;

[0016] S2. The Sn metal raw material weighed in step S1 is purified to obtain purified Sn metal.

[0017] S3. The purified Sn metal obtained in step S2 is mixed with the Co, Cr, Cu, Fe and Ni metal raw materials weighed in step S1, and the mixture is subjected to electric arc melting more than twice under a protective gas to obtain the master alloy.

[0018] S4. Mix the master alloy obtained in step S3 with the clean glass to obtain a mixture. Place the mixture into the vacuum chamber and position the mixture in the induction coil.

[0019] S5. Evacuate the vacuum chamber to a vacuum level of 1.0 × 10⁻⁶. -4 Pa, then backfill with high-purity Ar or high-purity He gas to 1.0 × 10⁻⁶. 4 ~1.0×10 5 Pa;

[0020] S6. Apply current to the induction coil in step S4 to heat and melt the mixture by induction heating and overheat it to 50-150K. After holding it at this temperature for 20-40s, a liquid alloy is obtained. Remove the current and allow the liquid alloy to undercool and solidify naturally to obtain a melt.

[0021] S7. Under ultra-high vacuum, the superheat of the melt obtained in step S6 is adjusted to control the supercooling of the melt, so that the supercooling of the melt reaches 150-325K. The induction heating melting and supercooling and solidification are repeated 1-3 times to obtain a Co-Cr-Cu-Fe-Ni-Sn system high-entropy alloy.

[0022] Preferably, step S2 includes the following steps:

[0023] S21. Pour dimethyl silicone oil into the Sn metal raw material weighed in step S1, so that the dimethyl silicone oil submerges the Sn metal raw material.

[0024] S22. Based on step S21, the Sn metal raw material is heated to above the liquidus temperature, held at that temperature for 15-25 seconds, and then naturally cooled. The heating and natural cooling process is repeated 1-3 times to achieve the melting and solidification of the Sn metal raw material, thereby obtaining purified Sn metal.

[0025] Preferably, in step S3, the current for arc melting is 80-130A, and the melting time is 10-30s.

[0026] Preferably, in step S3, the protective gas is high-purity Ar or high-purity He.

[0027] Preferably, in step S4, the mass ratio of the master alloy to the cleanroom glass is 1.5:1.

[0028] Preferably, in step S7, the degree of superheat of the melt obtained in step S6 is controlled by the following method:

[0029] When the supercooling of the melt obtained in step S6 is less than 150K, the high-frequency induction heating power is increased by adjusting the magnitude of the current applied to the induction coil, thereby increasing the superheating of the melt and thus increasing the supercooling of the melt.

[0030] Preferably, in steps S6 and S7, the dendrite growth rate during the melt solidification process is 5–139 mm / s, and...

[0031] Preferably, in step S7, the Vickers hardness of the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy is 300-450 HV.

[0032] Compared with the prior art, the advantages of this invention are as follows:

[0033] (1) The present invention uses melt immersion flotation technology to realize the melting and solidification process of Co-Cr-Cu-Fe-Ni-Sn system high entropy alloy. The process is simple, time-saving and easy.

[0034] (2) The present invention changes the high-frequency induction heating power parameters in real time according to the temperature change of the alloy melt, so that the melt reaches different superheated states, thereby increasing the supercooling of the melt, and finally achieving rapid solidification in a deep supercooled state. The maximum crystal growth rate can reach 139 mm / s, and the Vickers hardness of the rapidly solidified alloy can reach 300-450 HV. Due to the change of the supercooling process parameter, the supercooling is increased from 19K to 539K. That is, the present invention achieves active control of the solidification structure by regulating the supercooling, which promotes the homogenization of the alloy structure and the formation of high-entropy phase, and finally prepares a high-entropy alloy with better performance.

[0035] (3) Based on the traditional five-element Co-Cr-Cu-Fe-Ni high-entropy alloy, this invention prepares and synthesizes a new type of high-entropy alloy Co-Cr-Cu-Fe-Ni-Sn system by adding Sn element, which further improves the application performance of high-entropy alloy;

[0036] (4) The raw materials of the present invention are easy to obtain, the element ratio is simple, and the price is low and readily available. Attached Figure Description

[0037] Figure 1 A schematic diagram of a purification device for Sn metal raw materials;

[0038] Figure 2 Typical cooling curves for CoCrCuFeNiSn high-entropy alloys under melt immersion conditions;

[0039] Figure 3 The solidification microstructure of CoCrCuFeNiSn high-entropy alloys under different undercooling conditions under melt immersion conditions;

[0040] Figure 4 The composition content of the high-entropy phase in CoCrCuFeNiSn high-entropy alloys at 325 K;

[0041] Figure 5 The solidification microstructure of CoCrCu2FeNiSn high-entropy alloys under different undercooling conditions under melt immersion conditions;

[0042] Figure 6 The content of the high-entropy phase in the CoCrCu2FeNiSn high-entropy alloy at 424K is given. Detailed Implementation

[0043] The following will be described in conjunction with embodiments of the present invention. Figures 1 to 6 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] The Co, Cr, Cu, Fe, Ni and Sn metal raw materials in the embodiments of the present invention are manufactured by Zhongnuo New Materials (Beijing) Technology Co., Ltd., and the purity of each of the above metal raw materials is higher than 99.99%.

[0045] Example 1

[0046] This invention provides a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, which, by mass percentage, specifically comprises the following components:

[0047] Co: 14.4%, Cr: 12.8%, Cu: 15.6%, Fe: 13.7%, Ni: 14.4%, Sn: 29.1%. According to the above component ratios, the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy prepared in this embodiment of the invention can be mixed in equiatomic proportions of Co, Cr, Cu, Fe, Ni, and Sn. Therefore, the high-entropy alloy obtained in this embodiment is an equiatomic CoCrCuFeNiSn alloy.

[0048] This invention also provides a method for preparing the above-mentioned Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, specifically including the following steps:

[0049] S1. Weigh out the Co, Cr, Cu, Fe, Ni and Sn metal raw materials according to their mass percentages, and set aside for later use;

[0050] S2. The Sn metal raw material weighed in step S1 is purified to obtain purified Sn metal, specifically including the following steps:

[0051] S21. Place the Sn metal raw material weighed in step S1 into the bottom of a quartz test tube, and pour dimethyl silicone oil into the quartz test tube so that the dimethyl silicone oil submerges the Sn metal raw material.

[0052] S22. Based on step S21, hold the quartz test tube with a test tube clamp and place the bottom of the quartz test tube in the outer flame of an alcohol torch for heating. Heat the Sn metal raw material to above the liquidus temperature, hold for 15-25 seconds, and allow it to cool naturally. Repeat the heating and natural cooling process 1-3 times to melt and solidify the Sn metal raw material, obtaining purified Sn metal, such as... Figure 1 As shown.

[0053] S3. Mix the purified Sn metal obtained in step S2 with the Co, Cr, Cu, Fe and Ni metal raw materials weighed in step S1, and perform arc melting twice or more in a vacuum arc furnace under the protection of high-purity Ar or He gas to make the raw materials mix evenly and obtain the master alloy.

[0054] In this embodiment of the invention, the current for arc melting is 100A and the melting time is 20s.

[0055] S4. According to the mass ratio of 1.5:1, the master alloy obtained in step S3 and the clean glass are simultaneously placed into a high-purity alumina crucible and mixed to obtain a mixture. The high-purity alumina crucible containing the mixture is placed in a vacuum chamber and the mixture is placed in an induction coil.

[0056] The cleanroom glass in this embodiment of the invention (by mass fraction) contains 80% SiO2 and 20% Na2B4O7.

[0057] S5. Evacuate the vacuum chamber to a vacuum level of 1.0 × 10⁻⁶. -4 Pa, then backfill with high-purity Ar or high-purity He gas to 2.0 × 10⁻⁶. 4 Pa;

[0058] S6. Apply current to the induction coil in step S4 through a high-frequency induction heating power supply. Use a high-frequency induction heating device to heat and melt the mixture and overheat it to 150K. After holding it at that temperature for 30 seconds, a liquid alloy is obtained. Turn off the high-frequency power supply and allow the liquid alloy to achieve supercooling and solidification in natural cooling to obtain a melt.

[0059] S7. In an ultra-high vacuum environment, the superheat of the melt obtained in step S6 is adjusted to control the degree of supercooling of the melt. Specifically, when the degree of supercooling of the melt obtained in step S6 is less than 150K, the power of high-frequency induction heating is increased by adjusting the current applied to the induction coil to increase the degree of superheat of the melt, thereby increasing the degree of supercooling of the melt to 150-325K. The above induction heating melting and supercooling and solidification are repeated 1-3 times to ultimately achieve a degree of supercooling of 150-325K, thus obtaining a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy with a dendritic structure.

[0060] Typical cooling curves and solidification morphologies of the equiatomic CoCrCuFeNiSn high-entropy alloys obtained in the embodiments of the present invention are shown below. Figure 2 and Figure 3 As shown, through Figure 2 It can be seen that the undercooling range of the high-entropy alloy obtained in the embodiments of the present invention is 22–325 K; through Figure 3 It can be seen that no liquid phase separation occurred in the alloy samples within the supercooling range of 22–325 K. When the supercooling ΔT = 22 K, the dendrites were relatively coarse, and the solidification structure became significantly refined with increasing supercooling. When the supercooling ΔT = 325 K, EDS energy dispersive spectroscopy analysis was performed on the formed high-entropy phase, and the results are as follows: Figure 4 As shown, through Figure 4 It can be seen that the alloy sample contains Co, Cr, Cu, Fe, Ni, and Sn elements. Figure 4 The content of each atom in the alloy sample was calculated by combining the EDS energy dispersive spectroscopy data with the ZAF method, a standard-free quantitative analysis method, as shown in Table 1 below.

[0061] Table 1. Content of each atom in the high-entropy phase in the alloy sample at 325K

[0062] element Energy (keV) Atomic content (%) Cr 5.411 17.57 Fe 6.398 20.60 Co 6.924 21.96 Ni 7.471 18.06 Cu 8.040 9.19 Sn 3.442 12.61 total 100.00

[0063] As shown in Table 1, when the supercooling degree ΔT = 325K, the atomic percentage content of the high-entropy phase in the alloy sample is as follows: Co: 21.96%, Cr: 17.57%, Cu: 9.19%, Fe: 20.6%, Ni: 18.06%, Sn: 12.61%.

[0064] In the synthesis of Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys, photodiodes were used to record the reglow time of the primary phase during rapid solidification of the melt in real time. A microhardness tester was then used to test the hardness of rapidly solidified Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy samples with different degrees of undercooling. The test results showed that the dendrite growth rate of the synthesized alloys was 5–30 mm / s, and the Vickers hardness was 320–450 HV.

[0065] Example 2

[0066] This invention provides a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, which, by mass percentage, specifically comprises the following components:

[0067] Co: 12.5%, Cr: 11%, Cu: 27%, Fe: 11.9%, Ni: 12.4%, Sn: 25.2%. According to the above component ratios, the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy prepared in this embodiment of the invention can be mixed with Co, Cr, Fe, Ni, and Sn elements in equal atomic ratios, and Cu is mixed in twice the atomic ratio of the other components. Therefore, the high-entropy alloy obtained in this embodiment is CoCrCu2FeNiSn (atomic percentage).

[0068] The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy provided in this embodiment of the invention was prepared by the same method as in Example 1.

[0069] Figure 5 The solidification microstructure of the CoCrCu2FeNiSn (atomic percentage) high-entropy alloy obtained in the embodiments of the present invention under different undercooling conditions is shown by... Figure 5 It can be seen that the undercooling range of the high-entropy alloy obtained in the embodiments of the present invention is 19–539 K. Furthermore, through… Figure 5 (a) It can be seen that when the supercooling is 19K, a high-entropy alloy with dendritic structure is synthesized. Combined with the diode recording results, it was found that the dendrite growth rate of the synthesized dendrites was 11 mm / s, and the measured Vickers hardness was 338 HV. Figure 5 (b) and Figure 5(c) It can be seen that when the supercooling is 243K, the solidified structure is mostly dendritic, with a small portion exhibiting liquid-phase separation morphology. Liquid-phase separation occurred during solidification, resulting in micro-segregation. Liquid-phase separation easily leads to macro-segregation of the solute in high-entropy alloys, which is detrimental to improving the alloy's performance. That is, when the supercooling is 243K, a high-entropy alloy with micro-segregation is synthesized, with a dendrite growth rate of 15mm / s; therefore, 243K is the critical supercooling for liquid-phase separation to occur in the solidified structure. Figure 5 (d) and Figure 5 (e) It can be seen that as the supercooling increases further, the solidification structure forms a macroscopically segregated layered morphology. Specifically, when the supercooling is 424K and 539K, high-entropy alloys with macroscopic segregation are synthesized, with dendrite growth rates reaching 54mm / s and 139mm / s, respectively. When the supercooling ΔT = 424K, EDS energy dispersive spectroscopy analysis of the formed high-entropy phase yields the following results: Figure 6 As shown. (Through) Figure 6 It can be seen that the alloy sample contains Co, Cr, Cu, Fe, Ni, and Sn elements. Figure 6 The content of each atom in the high-entropy phase in the alloy sample was calculated by combining the EDS energy spectrum data with the ZAF method, a standard-free quantitative analysis method, as shown in Table 2 below.

[0070] Table 2. Content of each atom in the high-entropy phase in the alloy sample at 424K

[0071] element Energy (keV) Atomic content (%) Cr 5.411 20.77 Fe 6.398 24.87 Co 6.924 24.78 Ni 7.471 12.13 Cu 8.040 12.5 Sn 3.442 4.96 total 100.00

[0072] As shown in Table 2, when the supercooling degree ΔT = 424 K, the atomic percentage content of the high-entropy phase in the alloy sample is: Co: 24.78%, Cr: 20.77%, Cu: 12.5%, Fe: 24.87%, Ni: 12.13%, Sn: 4.96%.

[0073] Example 3

[0074] This invention provides a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, which, by mass percentage, specifically comprises the following components:

[0075] Co: 14%, Cr: 12.4%, Cu: 18.1%, Fe: 13.3%, Ni: 14%, Sn: 28.2%.

[0076] The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy provided in this embodiment of the invention was prepared by the same method as in Example 1.

[0077] Example 4

[0078] This invention provides a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, which, by mass percentage, specifically comprises the following components:

[0079] Co: 12.9%, Cr: 11.3%, Cu: 24.9%, Fe: 12.2%, Ni: 12.8%, Sn: 25.9%.

[0080] The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy provided in this embodiment of the invention was prepared by the same method as in Example 1.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy, characterized in that, By mass percentage, it includes the following components: Co: 12~15%, Cr: 10~13%, Cu: 15%~28%, Fe: 11~14%, Ni: 12~15%, Sn: 25~30%.

2. The Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy according to claim 1, characterized in that, By mass percentage, it includes the following components: Co: 14.4%, Cr: 12.8%, Cu: 15.6%, Fe: 13.7%, Ni: 14.4%, Sn: 29.1%.

3. A method for preparing a Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy according to claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh out the Co, Cr, Cu, Fe, Ni and Sn metal raw materials according to their mass percentages, and set aside for later use; S2. The Sn metal raw material weighed in step S1 is purified to obtain purified Sn metal. S3. The purified Sn metal obtained in step S2 is mixed with the Co, Cr, Cu, Fe and Ni metal raw materials weighed in step S1, and the mixture is subjected to electric arc melting more than twice under a protective gas to obtain the master alloy. The current for electric arc melting is 80–130A, and the melting time is 10–30s; S4. Mix the master alloy obtained in step S3 with the clean glass to obtain a mixture. Place the mixture into the vacuum chamber and position the mixture in the induction coil. S5. Evacuate the vacuum chamber to a vacuum level of 1.0 × 10⁻⁶. -4 Pa, then backfill with high-purity Ar or high-purity He gas to 1.0 × 10⁻⁶. 4 ~1.0×10 5 Pa; S6. Apply current to the induction coil in step S4 to heat and melt the mixture by induction heating and overheat it to 50~150K. After holding it at this temperature for 20~40s, a liquid alloy is obtained. Remove the current and allow the liquid alloy to undercool and solidify naturally to obtain a melt. S7. Under ultra-high vacuum, the superheat of the melt obtained in step S6 is adjusted to control the supercooling of the melt, so that the supercooling of the melt reaches 150-325K. The induction heating melting and supercooling and solidification are repeated 1-3 times to obtain a Co-Cr-Cu-Fe-Ni-Sn system high-entropy alloy.

4. The method for preparing the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy according to claim 3, characterized in that, Step S2 includes the following steps: S21. Pour dimethyl silicone oil into the Sn metal raw material weighed in step S1, so that the dimethyl silicone oil submerges the Sn metal raw material. S22. Based on step S21, the Sn metal raw material is heated to above the liquidus temperature, held at that temperature for 15-25 seconds, and then naturally cooled. The heating and natural cooling process is repeated 1-3 times to achieve the melting and solidification of the Sn metal raw material, thereby obtaining purified Sn metal.

5. The method for preparing Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys according to claim 3, characterized in that, In step S3, the protective gas is high-purity Ar or high-purity He.

6. The method for preparing Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys according to claim 3, characterized in that, In step S4, the mass ratio of the master alloy to the cleanroom glass is 1.5:

1.

7. The method for preparing Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys according to claim 3, characterized in that, In step S7, the degree of superheat of the melt obtained in step S6 is controlled by the following method: When the supercooling of the melt obtained in step S6 is less than 150K, the high-frequency induction heating power is increased by adjusting the magnitude of the current applied to the induction coil, thereby increasing the superheating of the melt and thus increasing the supercooling of the melt.

8. The method for preparing Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys according to claim 3, characterized in that, In steps S6 and S7, the dendrite growth rate during the melt solidification process is 5–139 mm / s.

9. The method for preparing Co-Cr-Cu-Fe-Ni-Sn high-entropy alloys according to claim 3, characterized in that, In step S7, the Vickers hardness of the Co-Cr-Cu-Fe-Ni-Sn high-entropy alloy is 300-450 HV.

Images