High-temperature strong-plasticity soft magnetic structure function integrated nickel-cobalt-based medium-entropy alloy material and preparation method thereof

Abstract

The invention discloses a high-temperature strong-plasticity soft magnetic structure function integrated nickel-cobalt-based medium-entropy alloy material and a preparation method thereof. The method comprises the steps that firstly, metal and intermediate alloy raw materials are prepared according to design components of a target product; 2, preparing the metal and intermediate alloy raw materials into a nickel-cobalt-based medium-entropy alloy cast ingot by adopting a vacuum arc furnace smelting method; and thirdly, the nickel-cobalt-based medium-entropy alloy cast ingot is subjected to solid solution and aging treatment, and the nickel-cobalt-based medium-entropy alloy material is obtained. By designing components of the nickel-cobalt-based entropy alloy and exploring smelting process and heat treatment process parameters of the alloy, uniform distribution of all elements in a nickel-cobalt-based entropy alloy cast ingot is promoted, dendritic segregation in the nickel-cobalt-based entropy alloy is eliminated, phase distribution nonuniformity generated in the gamma and gamma'phase precipitation process is further weakened, and the performance of the nickel-cobalt-based entropy alloy is improved. The soft magnetic nickel-cobalt-based structure and function integrated medium-entropy alloy material with high-temperature high plasticity is suitable for the fields of supercritical generator sets, high-temperature powder turbine discs, high-temperature-resistant electromagnetic wave-absorbing parts and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of medium-entropy alloys, and specifically relates to a nickel-cobalt-based medium-entropy alloy material with integrated high-temperature strong plasticity and soft magnetic structure and function, and a preparation method thereof. Background Art

[0002] Although the concept of multi-principal component alloys was initially controversial, these alloy preparation processes, which depart from traditional alloy design concepts, are now bearing fruit after two or three decades of exploration and development. Under certain elemental combinations, highly chaotic and high-entropy multi-principal component alloys can achieve eutectic equilibrium on the phase diagram, thereby enhancing structural and mechanical properties such as strength and ductility. Furthermore, the microstructural changes brought about by lattice distortion also enable these alloys to possess a variety of functional properties, such as excellent physical and magnetic properties, chemical corrosion resistance, and high-temperature oxidation resistance. Unlike traditional alloys that focus on a single property, multi-principal component alloys exhibit functional properties that are perfectly aligned with their mechanical properties, and these properties do not interfere with each other, creating a unique cocktail effect in these alloys. This has broadened the application range of these alloys, encompassing not only traditional engineering structural materials and mechanical components, but also a wide range of fields, including electrical engineering, energy and power, and petrochemicals. Applications include electromagnetic engines that must withstand severe loads, high-temperature powder turbine disks for aerospace, and cryogenic offshore icebreaking components. Among them, AlCoCrFeNiTi series high entropy alloys have attracted wide attention due to their light weight, high temperature ductility, magnetic properties and electrochemical properties. 45 (FeCoCr) 40 (AlTi) 15 、Al 10 Co 25 Cr8Fe 15 Ni 36 Ti6、Al 10 Co 18 Cr 10 Ni 55 Ti7, high temperature annealed Al9Co 15 Cr9Ni 59 Alloys such as Ti8 have demonstrated good high-temperature strength and plasticity. In addition, due to the presence of ferromagnetic elements such as Fe, Co, and Ni in these multi-principal alloys, these alloys have soft magnetic physical properties. Currently, AlCoCrNiFeTi based multi-principal alloys face challenges in improving the strength, wear resistance and high-temperature stability of the alloys. In order to overcome these challenges, some studies have attempted to regulate the subsequent heat treatment process of the alloy, and some studies have attempted to reduce the content of Fe in the alloy. However, for this type of medium-entropy alloy, the regulation of the plasticity of the alloy by the heat treatment process is still in the exploratory stage, and the reduction of the Fe content will seriously affect the soft magnetic properties of the alloy. How to design the alloy composition and adjust the subsequent heat treatment process of the alloy so that the AlCoCrNiTi based medium-entropy alloy without Fe elements and with Ni and Co elements as the main elements has good high-temperature strength and plasticity and exhibits soft magnetic properties is a problem that needs to be solved urgently in the current research field of structural and functional integrated materials for this type of medium-entropy alloy. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a method for preparing a nickel-cobalt-based medium-entropy alloy material with high-temperature strong plasticity and soft magnetic structure and function integration. This method designs a nickel-cobalt-based medium-entropy alloy without Fe element in the AlCoCrFeNiTi alloy system, then adopts a vacuum arc furnace melting method and coordinates the subsequent heat treatment process and parameters to significantly reduce the adverse factors such as element segregation, dendrites and alloy sensitivity to cracks in the cast nickel-cobalt-based medium-entropy alloy, thereby obtaining a nickel-cobalt-based medium-entropy alloy with good strong plasticity and soft magnetic properties at room temperature. This method solves the problems of low plasticity, uneven composition and poor soft magnetic properties of Fe-free nickel-cobalt-based medium-entropy alloys.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a high-temperature strong-plastic soft-magnetic structural and functional integrated nickel-cobalt-based medium-entropy alloy material, characterized in that the method comprises the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 7.5%-8.5%, Co 24%-25.5%, Cr 7.5%-8.5%, Ni 52.5%-53.5%, Ti 5.5%-6.5%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is not less than 1.2R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 300A~400A, and the vacuum degree is less than 1×10 -3 MPa, and multiple melting methods are used; Step 3: The nickel-cobalt-based medium-entropy alloy ingot obtained in step 2 is subjected to a solution treatment at 1200°C to 1250°C for 10h to 20h, and then subjected to an aging treatment at 800°C to 850°C for 5h to 7h to obtain a nickel-cobalt-based medium-entropy alloy material; the saturation magnetization of the nickel-cobalt-based medium-entropy alloy material is greater than 8emu / g, the coercive force is not higher than 30Oe, the compressive strength at 800°C exceeds 500MPa, and the deformation rate is not less than 10%.

[0005] During the research process of the present invention, it was found that in order to achieve the simultaneous soft magnetic functional properties and high-temperature structural mechanical properties of nickel-cobalt-based medium-entropy alloys, it is necessary to design the alloy composition and use appropriate heat treatment processes. In terms of composition design, based on the consideration and balance of the improvement in the high-temperature structural properties of the alloy brought by removing the Fe element in the AlCoCrFeNiTi alloy system and the reduction in the soft magnetic functional properties of the alloy, the present invention limits the composition of each element in the nickel-cobalt-based medium-entropy alloy to a relatively narrow range, that is, the nominal composition (in terms of atomic ratio) is near the medium-entropy alloy composition range of Al8Co25Cr8Ni53Ti6, and limits the entropy value of the nickel-cobalt-based medium-entropy alloy material to no less than 1.2R, so that it has obvious effects similar to high-entropy alloys, such as the cocktail effect, and can simultaneously meet the high-temperature structural properties and soft magnetic functional properties. In terms of subsequent heat treatment, it is necessary to use appropriate heat treatment processes to precipitate as many γ and γ′ high-temperature strengthening phases as possible and adjust the morphology of the high-temperature phases. Therefore, the solution temperature of the heat treatment is controlled to be 1200℃~1250℃, the holding time is 18h~22h, and the aging temperature of the heat treatment is controlled to be 800℃~850℃, and the holding time is 5h~7h.

[0006] The above-mentioned method for preparing a high-temperature strong plasticity soft magnetic structure and function integrated nickel-cobalt based medium entropy alloy material is characterized in that the types and mass percentages of the metal and master alloy raw materials in step 1 are: master alloy AlCr 60 8%~11%, NiCr 60 2%~5%, TiNi 30 The raw materials for the master alloy are 6% to 9%, the metal element Ni is 51% to 54%, and Co is 25% to 28%. The weighing errors of the metal elements and the master alloy raw materials are all less than ±0.1%. The present invention limits the types and mass percentages of the metal and master alloy raw materials and balances the melting points of the metal elements and the master alloy to ensure that the raw materials are fully melted and mixed, thus avoiding the serious consequence of uneven distribution of the elements during smelting due to differences in composition and density. The above-mentioned method for preparing a high-temperature, strong-plastic, soft-magnetic, structurally and functionally integrated nickel-cobalt-based medium-entropy alloy material is characterized in that, during the preparation process of the vacuum arc furnace melting method in step 2, a copper mold is used to cool the nickel-cobalt-based medium-entropy alloy melt, and the cooling rate is not less than 20°C / s. When the multiple melting method is used, the metal and intermediate alloy raw materials are melted and cooled to form an ingot, and then the ingot is turned over and melted again. The above melting process is repeated at least 5 times to ensure the uniform distribution of each element. The present invention limits the cooling rate to achieve rapid cooling, which is conducive to the fixation of the precipitated phase in the nickel-cobalt-based medium-entropy alloy.

[0007] The above-mentioned method for preparing a high-temperature, strong-ductile, soft-magnetic, structurally and functionally integrated nickel-cobalt-based medium-entropy alloy material is characterized by using wire cutting to obtain a block from the nickel-cobalt-based medium-entropy alloy material obtained in step three. The block is then polished using 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block drops below 1μm. The surface is then ultrasonically cleaned with alcohol to prepare a high-temperature compression specimen and a soft magnetic alloy specimen, respectively. Given the sensitivity of nickel-cobalt-based medium-entropy alloy materials to surface roughness, the roughness of the sample surface is limited to ensure that qualified high-temperature compression specimens and soft magnetic alloy specimens are obtained.

[0008] The above-mentioned method for preparing a high-temperature strong plasticity soft magnetic structural and functional integrated nickel-cobalt-based medium-entropy alloy material is characterized in that the high-temperature compression specimen is a cylindrical metal block with a diameter × height of 4mm × 6mm, and the soft magnetic alloy specimen is a metal block with a length, width and height of less than 2mm.

[0009] The above-mentioned method for preparing a high-temperature strong plasticity soft magnetic structure and function integrated nickel-cobalt based medium entropy alloy material is characterized in that a high-temperature compression sample is placed in a high-temperature universal testing machine after fine polishing, and the sample is subjected to a 1×10 -3 s -1 The high temperature compression mechanical properties test at 800℃ was carried out at a compression rate of .

[0010] The above-mentioned method for preparing a high-temperature strong-plastic soft magnetic structural and functional integrated nickel-cobalt-based medium-entropy alloy material is characterized in that a vibrating sample magnetometer is used to measure the static magnetic parameters of the soft magnetic alloy sample and obtain a hysteresis loop.

[0011] At the same time, the present invention also discloses a high-temperature strong plasticity soft magnetic structural and functional integrated nickel-cobalt based medium entropy alloy material prepared by the above method.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The nickel-cobalt-based medium-entropy alloy material of the present invention adds non-magnetic elements such as Al and Ti, and utilizes the distortion effect of the Al element on the alloy lattice to affect the movement form of electrons, which not only reduces the density of the nickel-cobalt-based medium-entropy alloy material, but also enables it to obtain good soft magnetic properties, ensuring that the nickel-cobalt-based medium-entropy alloy material simultaneously obtains high-temperature strong plasticity and soft magnetic functional properties, overcoming the problem of weakened magnetic properties of alloys without Fe elements, and expanding the application of nickel-cobalt-based medium-entropy alloy materials in the field of structural and functional integrated materials. It is suitable for supercritical generator sets, high-temperature powder turbine disks, and high-temperature resistant electromagnetic wave absorbing parts and other fields.

[0013] 2. The present invention adopts a vacuum arc furnace melting method combined with parameter design of the heat treatment method to precipitate fine square γ and γ′ high-temperature phases in the nickel-cobalt-based medium-entropy alloy material. This minimizes the influence of the alloy's increased sensitivity to cracks and failure during stretching caused by micro defects caused by uneven distribution of elements, coarse cast alloy grains, and uneven precipitation of coarse γ and γ′ phases, thereby greatly improving the strength and plasticity of the nickel-cobalt-based medium-entropy alloy material.

[0014] 3. The present invention discloses a composition of a nickel-cobalt based medium-entropy alloy material for use in a temperature range of 800°C, its preparation, and subsequent heat treatment process. By formulating an intermediate alloy and controlling the smelting process, the element distribution in the nickel-cobalt based medium-entropy alloy ingot is promoted to be more uniform. Combined with the control of the temperature and time of the solid solution and aging treatments, the dendritic segregation in the nickel-cobalt based medium-entropy alloy is effectively eliminated, the structural uniformity in the nickel-cobalt based medium-entropy alloy is promoted, and the high-temperature strength, plasticity, and soft magnetic functional properties of the nickel-cobalt based medium-entropy alloy material are further improved.

[0015] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a phase analysis diagram of the nickel-cobalt based medium entropy alloy material prepared in Example 1 of the present invention.

[0017] Figure 2 This is a diagram showing the element distribution of the nickel-cobalt based medium entropy alloy material prepared in Example 1 of the present invention.

[0018] Figure 3 Microstructure morphology of the nickel-cobalt based medium entropy alloy ingot and the nickel-cobalt based medium entropy alloy material prepared in Example 1 of the present invention.

[0019] Figure 4 This is a high-temperature stress-strain curve of the nickel-cobalt-based medium-entropy alloy material prepared in Example 1 of the present invention.

[0020] Figure 5 This is the hysteresis loop diagram of the nickel-cobalt based medium entropy alloy material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] Example 1 This embodiment includes the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 8%, Co 25%, Cr 8%, Ni 53%, Ti 6%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is 1.26R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; The types and mass percentages of the metal and master alloy raw materials are as follows: Master alloy AlCr 60 9.57%, NiCr 60 3.54%, TiNi 30 7.52%, metal element Ni 52.59%, Co 26.77%, and the weighing errors of metal elements and intermediate alloy raw materials are less than ±0.1%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 300A, and the vacuum degree is 1×10 -4 MPa, and a 5-time smelting method is used to melt the metal and master alloy raw materials and cool them to form an ingot, which is then turned over and smelted again; during the preparation process of the vacuum arc furnace smelting method, a copper mold is used to cool the nickel-cobalt based medium entropy alloy melt, and the cooling rate is not less than 20°C / s; Step 3: The nickel-cobalt based medium entropy alloy ingot prepared in step 2 is subjected to a solution treatment at 1220°C for 20 hours, and then subjected to an aging treatment at 800°C for 6 hours to obtain a nickel-cobalt based medium entropy alloy material.

[0022] Figure 1 This is the phase analysis diagram of the nickel-cobalt based medium entropy alloy material prepared in this embodiment. Figure 2 The element distribution diagram of the nickel-cobalt based medium entropy alloy material prepared in this embodiment is shown in FIG. Figure 1 and Figure 2 It can be seen that the nickel-cobalt based medium entropy alloy material shows γ and γ′ phase diffraction peaks, and the elements are evenly distributed.

[0023] Figure 3 The microstructure morphology of the nickel-cobalt based medium entropy alloy ingot and the nickel-cobalt based medium entropy alloy material prepared in this embodiment, wherein Figure (a) represents the cast nickel-cobalt based medium entropy alloy ingot, and Figure (b) represents the heat-treated nickel-cobalt based medium entropy alloy material. Figure 3It can be seen that compared with the cast nickel-cobalt-based medium-entropy alloy ingot, the presence of dendrites is eliminated in the nickel-cobalt-based medium-entropy alloy material after heat treatment, a large amount of γ and γ′ phases are precipitated in the alloy, and a small square morphology is presented, which is beneficial to improving the high-temperature strength and plasticity of the nickel-cobalt-based medium-entropy alloy material.

[0024] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped to below 1 μm. The surface was ultrasonically cleaned with alcohol to obtain a cylindrical high-temperature compression specimen with a diameter × height of 4 mm × 6 mm. The high-temperature compression specimen was placed on a high-temperature universal testing machine and subjected to a temperature of 800°C at a speed of 1×10 -3 s -1 The compression rate is used to test the compression mechanical properties and the Figure 4 The high temperature stress-strain curve shown in the figure is Figure 4 It can be seen that the compressive strength of the nickel-cobalt based medium entropy alloy material at a high temperature of 800°C is 550 MPa, and the deformation rate is 15%.

[0025] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped to below 1 μm, and the surface was ultrasonically cleaned with alcohol to obtain a soft magnetic alloy sample with a length, width, and height of less than 2 mm; the static magnetic parameters of the soft magnetic alloy sample were measured using a vibrating sample magnetometer, and the results were plotted as follows: Figure 5 The hysteresis loop diagram shown in Figure 5 It can be seen that the saturation magnetization intensity of the nickel-cobalt based medium entropy alloy material is 8.6emu / g and the coercive force is 27Oe.

[0026] Example 2 This embodiment includes the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 7.5%, Co25.5%, Cr 7.5%, Ni 53.5%, Ti 6%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is 1.24R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; The types and mass percentages of the metal and master alloy raw materials are as follows: Master alloy AlCr 60 8.94%, NiCr 60 3.31%, TiNi 307.50%, metal element Ni 53.04%, Co 27.21%, and the weighing errors of metal elements and intermediate alloy raw materials are all less than ±0.1%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 300A, and the vacuum degree is 1×10 -4 MPa, and a 5-time smelting method is used to melt the metal and master alloy raw materials and cool them to form an ingot, which is then turned over and smelted again; during the preparation process of the vacuum arc furnace smelting method, a copper mold is used to cool the nickel-cobalt based medium entropy alloy melt, and the cooling rate is not less than 20°C / s; Step 3: The nickel-cobalt based medium entropy alloy ingot prepared in step 2 is subjected to a solution treatment at 1200°C for 10 hours, and then subjected to an aging treatment at 800°C for 5 hours to obtain a nickel-cobalt based medium entropy alloy material.

[0027] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped to below 1 μm. The surface was ultrasonically cleaned with alcohol to obtain a cylindrical high-temperature compression specimen with a diameter × height of 4 mm × 6 mm. The high-temperature compression specimen was placed on a high-temperature universal testing machine and subjected to a temperature of 800°C at a speed of 1×10 -3 s -1 The compression mechanical properties test was carried out at a compression rate of 1000 nm. The results showed that the compressive strength of the nickel-cobalt based medium entropy alloy material at a high temperature of 800°C was 520 MPa and the deformation rate was 12%.

[0028] A block is obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block drops below 1 μm. The surface is ultrasonically cleaned with alcohol to obtain a soft magnetic alloy sample with a length, width, and height of less than 2 mm. The static magnetic parameters of the soft magnetic alloy sample are measured using a vibrating sample magnetometer, and the results show that the saturation magnetization intensity of the nickel-cobalt-based medium-entropy alloy material is 9 emu / g and the coercive force is 25 Oe.

[0029] Example 3 This embodiment includes the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 8.5%, Co24%, Cr 8.5%, Ni 52.5%, Ti 6.5%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is 1.27R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; The types and mass percentages of the metal and master alloy raw materials are as follows: Master alloy AlCr 60 10.22%, NiCr 60 3.78%, TiNi 30 8.19%, metal element Ni 51.99%, Co 25.82%, and the weighing errors of metal elements and intermediate alloy raw materials are all less than ±0.1%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 400A, and the vacuum degree is 1×10 -4 MPa, and a 5-time smelting method is used to melt the metal and master alloy raw materials and cool them to form an ingot, which is then turned over and smelted again; during the preparation process of the vacuum arc furnace smelting method, a copper mold is used to cool the nickel-cobalt based medium entropy alloy melt, and the cooling rate is not less than 20°C / s; Step 3: The nickel-cobalt based medium entropy alloy ingot prepared in step 2 is subjected to a solution treatment at 1250°C for 20 hours, and then subjected to an aging treatment at 850°C for 7 hours to obtain a nickel-cobalt based medium entropy alloy material.

[0030] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped to below 1 μm. The surface was ultrasonically cleaned with alcohol to obtain a cylindrical high-temperature compression specimen with a diameter × height of 4 mm × 6 mm. The high-temperature compression specimen was placed on a high-temperature universal testing machine and subjected to a temperature of 800°C at a speed of 1×10 -3 s -1 The compression mechanical properties test was carried out at a compression rate of 10 ...

[0031] A block is obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block drops below 1 μm. The surface is ultrasonically cleaned with alcohol to obtain a soft magnetic alloy sample with a length, width, and height of less than 2 mm. The static magnetic parameters of the soft magnetic alloy sample are measured using a vibrating sample magnetometer, and the results show that the saturation magnetization intensity of the nickel-cobalt-based medium-entropy alloy material is 8.4 emu / g and the coercive force is 30 Oe.

[0032] Example 4 This embodiment includes the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 7.5%, Co25.5%, Cr 8%, Ni 53.5%, Ti 5.5%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is 1.24R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; The types and mass percentages of the metal and master alloy raw materials are as follows: Master alloy AlCr 60 8.86%, NiCr 60 4.14%, TiNi 30 8.05%, metal element Ni 51.97%, Co 26.97%, and the weighing error of metal element and master alloy raw materials is less than ±0.1%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 400A, and the vacuum degree is 1×10 -4 MPa, and a 5-time smelting method is used to melt the metal and master alloy raw materials and cool them to form an ingot, which is then turned over and smelted again; during the preparation process of the vacuum arc furnace smelting method, a copper mold is used to cool the nickel-cobalt based medium entropy alloy melt, and the cooling rate is not less than 20°C / s; Step 3: The nickel-cobalt based medium entropy alloy ingot prepared in step 2 is subjected to a solution treatment at 1220°C for 15 hours, and then subjected to an aging treatment at 850°C for 5 hours to obtain a nickel-cobalt based medium entropy alloy material.

[0033] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped to below 1 μm. The surface was ultrasonically cleaned with alcohol to obtain a cylindrical high-temperature compression specimen with a diameter × height of 4 mm × 6 mm. The high-temperature compression specimen was placed on a high-temperature universal testing machine and subjected to a temperature of 800°C at a speed of 1×10 -3 s -1 The compression mechanical properties test was carried out at a compression rate of 10 ...

[0034] A block was obtained from the nickel-cobalt-based medium-entropy alloy material prepared by the present invention by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped below 1 μm. The surface was ultrasonically cleaned with alcohol to obtain a soft magnetic alloy sample with a length, width, and height of less than 2 mm. The static magnetic parameters of the soft magnetic alloy sample were measured using a vibrating sample magnetometer, and the results showed that the saturation magnetization intensity of the nickel-cobalt-based medium-entropy alloy material was 9.6 emu / g and the coercive force was 23 Oe.

[0035] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a high-temperature strong-plastic soft-magnetic structural and functional integrated nickel-cobalt-based medium-entropy alloy material, characterized in that: The method comprises the following steps: Step 1: Prepare metal and intermediate alloy raw materials according to the designed composition of the target product nickel-cobalt-based medium-entropy alloy material; the atomic percentage of each element in the designed composition of the target product nickel-cobalt-based medium-entropy alloy material is: Al 7.5%-8.5%, Co 24%-25.5%, Cr 7.5%-8.5%, Ni 52.5%-53.5%, Ti 5.5%-6.5%, and the entropy value of the target product nickel-cobalt-based medium-entropy alloy material is not less than 1.2R; the atomic mass ratio deviation of each element in the metal and intermediate alloy raw materials is less than ±0.1%, and the mass purity of the metal and intermediate alloy raw materials is greater than 99.9%; Step 2: The metal and master alloy raw materials prepared in step 1 are made into nickel-cobalt based medium entropy alloy ingots by vacuum arc furnace melting method; the melting current of the vacuum arc furnace melting method is 300A~400A, and the vacuum degree is less than 1×10 -3 MPa, and multiple melting methods are used; Step 3: The nickel-cobalt-based medium-entropy alloy ingot obtained in step 2 is subjected to a solution treatment at 1200°C to 1250°C for 10h to 20h, and then subjected to an aging treatment at 800°C to 850°C for 5h to 7h to obtain a nickel-cobalt-based medium-entropy alloy material; the saturation magnetization of the nickel-cobalt-based medium-entropy alloy material is greater than 8emu / g, the coercive force is not higher than 30Oe, the compressive strength at 800°C exceeds 500MPa, and the deformation rate is not less than 10%.

2. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 1, characterized in that: The types and mass percentages of the metal and master alloy raw materials in step 1 are: Master alloy AlCr 60 8%~11%, NiCr 60 2%~5%, TiNi 30 6%~9%, metal element Ni 51%~54%, Co 25%~28%, and the weighing error of metal element and intermediate alloy raw materials is less than ±0.1%.

3. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 1, characterized in that: During the preparation process of the vacuum arc furnace melting method described in step 2, a copper mold is used to cool the nickel-cobalt based medium entropy alloy melt at a cooling rate of not less than 20°C / s. When the multiple melting method is adopted, the metal and intermediate alloy raw materials are melted and cooled to form an ingot, and then the ingot is turned over and melted again. The above melting process is repeated at least 5 times to ensure the uniformity of the distribution of each element.

4. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 1, characterized in that: A block was obtained from the nickel-cobalt-based medium-entropy alloy material obtained in step three by wire cutting, and then polished with 600#, 800#, 1000#, and 1500# sandpaper in sequence until the surface roughness of the metal block dropped below 1μm. The surface was then ultrasonically cleaned with alcohol and used as high-temperature compression specimens and soft magnetic alloy specimens, respectively.

5. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 4, characterized in that: The high-temperature compression specimen is a cylindrical metal block with a diameter×height of 4 mm×6 mm, and the soft magnetic alloy specimen is a metal block with a length, width and height all less than 2 mm.

6. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 1, characterized in that: After fine polishing, the high temperature compression specimen was placed in a high temperature universal testing machine with a 1×10 -3 s -1 The high temperature compression mechanical properties test at 800℃ was carried out at a compression rate of .

7. The method for preparing a high-temperature strong-plastic soft-magnetic structural-functional integrated nickel-cobalt-based medium-entropy alloy material according to claim 4, characterized in that: The static magnetic parameters of the soft magnetic alloy samples were measured using a vibrating sample magnetometer, and the hysteresis loops were obtained.

8. A nickel-cobalt-based medium-entropy alloy material with high-temperature strong plasticity and soft magnetic structure and function integration prepared by the method according to any one of claims 1 to 7.

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