High entropy alloy and method for manufacturing the same

Abstract

The present application provides a high-entropy alloy and a method for manufacturing the same. The microstructure of the high-entropy alloy includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure, and an ultrafine grain structure. In the high-entropy alloy provided in the embodiments of the present application, the nanotwin structure has the characteristics of high strength and high thermal stability, the multidirectional annealed twin structure has a strong work hardening ability, the nanocrystalline structure has the characteristics of high strength and high hardness, and the ultrafine grain structure can provide plastic deformation ability. Therefore, the high-entropy alloy provided in the embodiments of the present application has the above-mentioned microstructure, thereby giving it higher mechanical properties.

Description

Technical Field

[0001] The present application relates to the field of alloy technology, and in particular to a high entropy alloy and a method for manufacturing the same. Background Art

[0002] Traditional alloys are typically metallic materials with metallic properties, formed by combining a primary element and other minor auxiliary elements through alloying processes (such as smelting, mechanical alloying, sintering, vapor deposition, etc.). The addition of these minor elements significantly improves the performance of traditional alloys, enabling them to meet the application needs of most fields. However, as the number of metallic elements in traditional alloys increases, a large number of complex and brittle intermetallic compounds or intermediate phases precipitate within them, deteriorating the alloy's performance and significantly complicating the alloy's microstructure and elemental analysis. This results in the disappearance of the material's unique microstructure and limits its mechanical properties.

[0003] With the rapid development of alloy technology, the emergence of high-entropy alloys (HEAs) has broken the design concept of element content in traditional alloys. They use a method of mixing multiple elements in equal atomic ratios, without the need to design the main elements. This allows HEAs to be disordered at the atomic scale, that is, the atomic arrangement of the alloy is in a highly chaotic state. This allows HEAs to have many properties superior to traditional alloys, such as low stacking fault energy, high thermal stability, high radiation resistance, good corrosion resistance, and good high-temperature mechanical properties. As alloys are applied in various fields, the requirements for their performance are also becoming increasingly higher. Therefore, there is an urgent need to develop a HEA with higher performance. Summary of the Invention

[0004] The present application provides a high entropy alloy and a method for manufacturing the same. The high entropy alloy has a variety of microstructures, which gives it higher mechanical properties.

[0005] In a first aspect, an embodiment of the present application provides a high entropy alloy, the microstructure of which includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure, and an ultrafine grain structure.

[0006] In the high-entropy alloy provided in the embodiments of the present application, its microstructure includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure and an ultrafine grain structure, among which the nanotwin structure has the characteristics of high strength and high thermal stability, the multidirectional annealed twin structure has a strong work hardening ability, the nanocrystalline structure has the characteristics of high strength and high hardness, and the ultrafine grain structure can provide plastic deformation ability. Therefore, the high-entropy alloy provided in the embodiments of the present application has the above-mentioned microstructure, so that it has higher mechanical properties.

[0007] According to any of the aforementioned embodiments of the first aspect of the present application, the nano-twinned microstructure has twins with a thickness less than or equal to 27 nm.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the multidirectional annealed twinned microstructure has grains with a grain size less than or equal to 2.1 μm;

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, the nanocrystalline structure has grains with a size less than or equal to 30 nm.

[0010] According to any of the aforementioned embodiments of the first aspect of the present application, the ultrafine-grained microstructure has grains with a size less than or equal to 1.5 μm.

[0011] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 30%.

[0012] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 15%.

[0013] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 10%.

[0014] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 30%.

[0015] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 20%.

[0016] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 15%.

[0017] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 40%.

[0018] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 35%.

[0019] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 20%.

[0020] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 50%.

[0021] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 40%.

[0022] According to any of the aforementioned embodiments of the first aspect of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 20%.

[0023] According to any of the aforementioned embodiments of the first aspect of the present application, the yield strength of the high entropy alloy is greater than or equal to 786 MPa.

[0024] According to any of the aforementioned embodiments of the first aspect of the present application, the tensile strength of the high entropy alloy is greater than or equal to 942 MPa.

[0025] In a second aspect, an embodiment of the present application provides a method for manufacturing a high entropy alloy as described in the first aspect of the present application, comprising:

[0026] Cold rolling process, which subjects the wrought alloy to multiple passes of cold rolling;

[0027] In the annealing process, the cold-rolled forged alloy is annealed at 500°C-700°C to obtain a high-entropy alloy.

[0028] According to any of the aforementioned embodiments of the second aspect of the present application, in the cold rolling process, the iron-based forging alloy is rolled with a reduction of 80%-90% in the thickness direction.

[0029] According to any of the aforementioned embodiments of the second aspect of the present application, the rolling reduction in each pass is 2%-6%.

[0030] According to any of the aforementioned embodiments of the second aspect of the present application, in the annealing process, the annealing treatment time is 30 minutes to 50 minutes.

[0031] The above description is only an overview of the technical solution of this specification. In order to more clearly understand the technical means of this specification, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of this specification more obvious and easy to understand, the specific implementation methods of this specification are listed below.

[0032] Figures in the specification

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1The TEM bright field image of the microstructure of the high entropy alloy provided in Example 1 of the present application is shown;

[0035] Figure 2 The TEM dark field image of the microstructure of the high entropy alloy provided in Example 1 of the present application is shown;

[0036] Figure 3 TEM bright field image of the microstructure of the high entropy alloy provided in Example 2 of the present application is shown;

[0037] Figure 4 The TEM dark field image of the microstructure of the high entropy alloy provided in Example 2 of the present application is shown;

[0038] Figure 5 TEM bright field image of the microstructure of the high entropy alloy provided in Example 3 of the present application is shown;

[0039] Figure 6 The TEM dark field image of the microstructure of the high entropy alloy provided in Example 3 of the present application is shown;

[0040] Figure 7 A TEM bright field image of the microstructure of the high entropy alloy provided in Comparative Example 1 is shown;

[0041] Figure 8 A TEM dark field image of the microstructure of the high entropy alloy provided in Comparative Example 1 is shown. DETAILED DESCRIPTION

[0042] As used herein, "ranges" are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit, the selected lower and upper limits defining the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, i.e., any lower limit may be combined with any upper limit to form a range.

[0043] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0044] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0045] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0046] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0047] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0048] Unless otherwise specified, the terms used in this application have the common meanings that are commonly understood by those skilled in the art.

[0049] Unless otherwise stated, the numerical values ​​of the parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in the embodiments of this application.

[0050] At present, the microstructure of high-entropy alloys usually includes a dual-scale structure among coarse-grained / ultrafine-grained structure, ultrafine-grained / nanocrystalline structure or coarse-grained / nanocrystalline structure, which enables high-entropy alloys to have the characteristics of this dual-scale structure. As the application fields of high-entropy alloys have higher requirements for their properties, there is an urgent need to develop high-entropy alloys with higher performance.

[0051] In view of this, an embodiment of the present application provides a high entropy alloy and a method for manufacturing the same. The high entropy alloy has a variety of microstructures, which gives it higher mechanical properties.

[0052] In the present application, the metal elements contained in the high entropy alloy can be conventional metal elements in the art, and the embodiments of the present application do not impose specific restrictions on this. For example, the high entropy alloy can be a nickel-based high entropy alloy, an iron-based high entropy alloy, etc. In order to facilitate the detailed description of the following embodiments, the following embodiments all take CoCrFeNi high entropy alloy as an example, and the CoCrFeNi high entropy alloy and its manufacturing method are described in detail.

[0053] In a first aspect, an embodiment of the present application provides a high entropy alloy, the microstructure of which includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure, and an ultrafine grain structure.

[0054] In the present application, the nano-twinned structure is generally composed of deformation twins with a layer thickness of several nanometers to tens of nanometers. The nano-twinned structure has the characteristics of high yield strength and relatively high thermal stability.

[0055] Multi-directional annealing twin structure generally refers to annealing twins with multiple directions inside the grain. Taking face-centered cubic crystal as an example: it has four twin planes: (111), and Annealing twins can form in four directions within the same grain. Compared to deformation twins, which have a large number of dislocations on the twin planes, annealing twins have a small number of dislocations (or almost no dislocations) on the twin planes. Therefore, the twin planes and dislocations in annealing twins interact to produce strengthening, and the annealing twin structure has good work hardening ability.

[0056] Nanocrystalline microstructure generally refers to a microstructure with a grain size ranging from tens of nanometers to several tens of nanometers, which usually has the characteristics of high strength and high hardness.

[0057] Ultrafine-grained microstructure generally refers to a grain structure with a grain size distribution ranging from hundreds of nanometers to several microns. Ultrafine grains generally have good plastic deformation ability.

[0058] In the embodiments of the present application, the nanotwin microstructure, multidirectional annealing twin microstructure, nanocrystalline microstructure and ultrafine grain microstructure can be observed and characterized using instruments and methods well known in the art, such as a transmission electron microscope (TEM).

[0059] In the high-entropy alloy provided in the embodiments of the present application, its microstructure includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure and an ultrafine grain structure, among which the nanotwin structure has the characteristics of high strength and high thermal stability, the multidirectional annealed twin structure has a strong work hardening ability, the nanocrystalline structure has the characteristics of high strength and high hardness, and the ultrafine grain structure can provide plastic deformation ability. Therefore, the high-entropy alloy provided in the embodiments of the present application has the above-mentioned microstructure, so that it has higher mechanical properties.

[0060] In some embodiments of the present application, the nano-twin structure has twins with a thickness less than or equal to 27 nm. The twin thickness in the nano-twin structure is within the above range, which can help improve the yield strength of the high entropy alloy.

[0061] In some examples, the twin thickness in the nanotwin structure can be, but is not limited to, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, or a range of two of the above values. For example, the twin thickness in the nanotwin structure can be, but is not limited to, 1 nm-25 nm, 2 nm-24 nm, 4 nm-20 nm, 5 nm-18 nm, or 6 nm-15 nm.

[0062] In some embodiments of the present application, the multi-directional annealed twin structure has grains with a size less than or equal to 2.1 μm. The grain size distribution of the multi-directional annealed twin structure is within the above range, which can make the high entropy alloy have a higher yield strength.

[0063] In some examples, the grain size of the multi-directional annealed twin structure may be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 2.1 μm, or a range consisting of any two of the above values. For example, the grain size of the multi-directional annealed twin structure may be, but is not limited to, 0.1 μm-2 μm, 0.2 μm-1.8 μm, 0.5 μm-1.5 μm, or 0.6 μm-1.2 μm.

[0064] In some embodiments of the present application, the nanocrystalline structure has grains with a size less than or equal to 30 nm. When the grain size distribution of the nanocrystalline structure is within the above range, the strength and hardness of the high entropy alloy can be further improved.

[0065] In some examples, the size of the grains in the nanocrystalline structure can be, but is not limited to, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, or a range consisting of any two of the above values. For example, the size of the grains in the nanocrystalline structure can be, but is not limited to, 1 nm-28 nm, 4 nm-25 nm, 6 nm-21 nm, 8 nm-18 nm, or 10 nm-16 nm.

[0066] In some embodiments of the present application, the ultrafine-grained microstructure has grains with a size less than or equal to 1.5 μm. When the grain size distribution of the ultrafine-grained microstructure is within the above range, the plastic deformation ability, ie, the tensile strength, of the high-entropy alloy can be further improved.

[0067] In some examples, the grain size of the ultrafine-grained microstructure may be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, or a range consisting of any two of the foregoing values. For example, the grain size of the ultrafine-grained microstructure may be, but is not limited to, 0.1 μm-1.5 μm, 0.2 μm-1.3 μm, 0.4 μm-1.2 μm, or 0.6 μm-1 μm.

[0068] In some embodiments of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 30%.

[0069] In other embodiments of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 15%.

[0070] In some other embodiments of the present application, the volume fraction of the nano-twinned structure in the microstructure is less than or equal to 10%.

[0071] In some examples, the volume fraction of the nanotwinned structure in the microstructure can be, but is not limited to, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or a range consisting of any two of the above values. For example, the volume fraction of the nanotwinned structure in the microstructure can be, but is not limited to, 10%-30%, 12%-28%, 14%-26%, 15%-25%, or 16%-24%.

[0072] In some embodiments of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 30%.

[0073] In some other embodiments of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 20%.

[0074] In some other embodiments of the present application, the volume fraction of the multidirectional annealing twin structure in the microstructure is less than or equal to 15%.

[0075] In some examples, the volume fraction of the multi-directional annealed twin structure in the microstructure can be, but is not limited to, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or a range consisting of any two of the above values. For example, the volume fraction of the multi-directional annealed twin structure in the microstructure can be, but is not limited to, 10%-30%, 11%-29%, 13%-27%, 15%-24%, 16%-22%, or 17%-20%.

[0076] In some embodiments of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 40%.

[0077] In other embodiments of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 35%.

[0078] In some other embodiments of the present application, the volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 20%.

[0079] In some examples, the volume fraction of the nanocrystalline structure in the microstructure can be, but is not limited to, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or a range consisting of any two of the above values. For example, the volume fraction of the nanocrystalline structure in the microstructure can be, but is not limited to, 20%-40%, 21%-38%, 23%-35%, 25%-33%, or 27%-32%.

[0080] In some embodiments of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 50%.

[0081] In some other embodiments of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 40%.

[0082] In some other embodiments of the present application, the volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 20%.

[0083] In some examples, the volume fraction of the ultrafine grained structure in the microstructure may be, but is not limited to, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or a range consisting of any two of the above values. For example, the volume fraction of the ultrafine grained structure in the microstructure may be, but is not limited to, 20%-50%, 22%-48%, 23%-45%, 25%-42%, 27%-40%, or 28%-38%.

[0084] In some embodiments of the present application, the yield strength of the high entropy alloy is greater than or equal to 786 MPa.

[0085] In some embodiments of the present application, the tensile strength of the high entropy alloy is greater than or equal to 942 MPa.

[0086] In a second aspect, an embodiment of the present application provides a method for manufacturing a high entropy alloy as described in the first aspect of the present application, comprising:

[0087] S100, cold rolling process, performing multiple cold rolling processes on the iron-based forging alloy;

[0088] S200, annealing process, annealing the cold-rolled iron-based forging alloy at 500°C-700°C to obtain a high entropy alloy.

[0089] In the manufacturing method of the high entropy alloy provided in the embodiment of the present application, in the cold rolling process of S100, the iron-based forging alloy is subjected to multiple cold rolling treatments to obtain equiaxed nanocrystals, lamellar nanocrystals and nanotwin structures containing a relatively high dislocation density. During the subsequent annealing process, these positions with high dislocation density can provide nucleation points for the generation of annealing twins, ensuring that a large number of annealing twins in different directions are generated simultaneously.

[0090] In some embodiments of the present application, in the cold rolling process, the iron-based wrought alloy is rolled with a reduction of 80%-90% in the thickness direction.

[0091] In some embodiments of the present application, the rolling reduction in each pass is 2%-6%.

[0092] In this application, the rolling reduction per pass is generally relative to the thickness of the original billet.

[0093] In some embodiments of the present application, in the annealing process, the annealing treatment time is 30 minutes to 50 minutes.

[0094] The following embodiments describe the present disclosure in more detail, and these embodiments are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are by mass, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0095] Example 1

[0096] This embodiment provides a method for manufacturing a high-entropy alloy. In this embodiment, a wrought CoCrFeNi high-entropy alloy having a face-centered cubic structure is used to prepare a block sample with a thickness of 10 mm, a length of 32 mm, and a width of 32 mm by electric spark cutting. The manufacturing method includes the following steps:

[0097] In the cold rolling process, the block sample is subjected to multiple cold rolling deformation treatments at room temperature using a rolling mill, with a reduction of 0.2 mm each time, to obtain a cold-rolled sheet with a thickness of 1.6 mm. The rolling reduction of the sample is 84%;

[0098] In the annealing process, the cold-rolled thin plate is annealed in an air atmosphere at a temperature of 600°C for 30 minutes. After the power is turned off, the cold-rolled thin plate is cooled to room temperature in the furnace to obtain a CoCrFeNi high-entropy alloy including a nano-twin structure, a multi-directional annealed twin structure, a nano-crystalline structure and an ultra-fine-grained structure.

[0099] Example 2

[0100] This embodiment provides a method for manufacturing a high-entropy alloy. In this embodiment, a wrought CoCrFeNi high-entropy alloy having a face-centered cubic structure is used to prepare a block sample with a thickness of 10 mm, a length of 32 mm, and a width of 32 mm by electric spark cutting. The manufacturing method includes the following steps:

[0101] In the cold rolling process, the block sample is subjected to multiple cold rolling deformation treatments at room temperature using a rolling mill, with a reduction of 0.2 mm each time, to obtain a cold-rolled sheet with a thickness of 1.6 mm. The rolling reduction of the sample is 84%;

[0102] In the annealing process, the cold-rolled thin plate is annealed in an air atmosphere at a temperature of 600°C for 40 minutes. After the power is turned off, the cold-rolled thin plate is cooled to room temperature in the furnace to obtain a CoCrFeNi high-entropy alloy including a nano-twin structure, a multi-directional annealed twin structure, a nano-crystalline structure and an ultra-fine-grained structure.

[0103] Example 3

[0104] This embodiment provides a method for manufacturing a high-entropy alloy. In this embodiment, a wrought CoCrFeNi high-entropy alloy having a face-centered cubic structure is used to prepare a block sample with a thickness of 10 mm, a length of 32 mm, and a width of 32 mm by electric spark cutting. The manufacturing method includes the following steps:

[0105] In the cold rolling process, the block sample is subjected to multiple cold rolling deformation treatments at room temperature using a rolling mill, with a reduction of 0.2 mm each time, to obtain a cold-rolled sheet with a thickness of 1.6 mm. The rolling reduction of the sample is 84%;

[0106] In the annealing process, the cold-rolled thin plate is annealed in an air atmosphere at a temperature of 600°C for 50 minutes. After the power is turned off, the cold-rolled thin plate is cooled to room temperature in the furnace to obtain a CoCrFeNi high-entropy alloy including a nano-twin structure, a multi-directional annealed twin structure, a nano-crystalline structure and an ultra-fine-grained structure.

[0107] Comparative Example 1

[0108] The manufacturing method is similar to that of Example 1, except that the annealing temperature in the annealing process is 700° C. and the time is 5 minutes.

[0109] Test section

[0110] (1) Microstructure test of CoCrFeNi high entropy alloy

[0111] The microstructure of the CoCrFeNi high entropy alloy was detected using a transmission electron microscope (TEM) under bright field and dark field scenes to obtain TEM bright field images and TEM dark field images, as shown in Figure 2. Figure 1-8 As shown, through Figure 1-6 It can be seen that the microstructures of the CoCrFeNi high entropy alloys in Examples 1-3 include nano-twin structure, multi-directional annealing twin structure, nano-crystalline structure and ultra-fine grain structure; Figure 7 and Figure 8 It can be seen that the microstructure of the CoCrFeNi high entropy alloy in Comparative Example 1 consists of an annealed twin structure and an ultrafine grain structure.

[0112] (2) Yield strength test

[0113] The yield strength test of materials shall comply with GB228.1.

[0114] (3) Tensile strength test

[0115] The tensile strength test of the material shall comply with GB228.1.

[0116] Table 1 lists the volume fraction of the microstructure and the corresponding mechanical properties of the CoCrFeNi high entropy alloy in Examples 1-3 and Comparative Example 1, respectively.

[0117] Table 1

[0118]

[0119] According to Table 1, by comparing the experimental data of Examples 1-3 and Comparative Example 1, it can be seen that the microstructure of the high-entropy alloy provided in the embodiments of the present application includes a nanotwin structure, a multidirectional annealed twin structure, a nanocrystalline structure and an ultrafine grain structure, which can enable it to have higher yield strength and tensile strength.

[0120] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned experimental examples, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned experimental examples, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the experimental examples of the present application.

Claims

1. A high entropy alloy, characterized in that The microstructure of the high entropy alloy includes a nano twin structure, a multi-directional annealed twin structure, a nanocrystalline structure and an ultrafine grain structure; the high entropy alloy is a CoCrFeNi high entropy alloy; The nano-twinned structure has twins with a thickness less than or equal to 27 nm; The multi-directional annealed twinned microstructure has grains with a grain size less than or equal to 2.1 μm; The nanocrystalline structure has grains with a size less than or equal to 30 nm; The ultrafine grain structure has grains with a size less than or equal to 1.5 μm.

2. The high entropy alloy according to claim 1, characterized in that The volume fraction of the nano twin structure in the microstructure is less than or equal to 30%.

3. The high entropy alloy according to claim 1, characterized in that The volume fraction of the multidirectional annealed twin structure in the microstructure is less than or equal to 30%.

4. The high entropy alloy according to claim 1, characterized in that The volume fraction of the nanocrystalline structure in the microstructure is less than or equal to 40%.

5. The high entropy alloy according to claim 1, characterized in that The volume fraction of the ultrafine grain structure in the microstructure is less than or equal to 50%.

6. The high entropy alloy according to any one of claims 1 to 5, characterized in that The yield strength of the high entropy alloy is greater than or equal to 786 MPa; The tensile strength of the high entropy alloy is greater than or equal to 942 MPa.

7. A method for producing a high entropy alloy according to any one of claims 1 to 6, characterized in that: include: Cold rolling process, which subjects the wrought alloy to multiple passes of cold rolling; In the annealing process, the cold-rolled forged alloy is annealed at 500°C-700°C to obtain a high entropy alloy.

8. The manufacturing method according to claim 7, characterized in that In the cold rolling process, the wrought alloy is rolled with a reduction of 80% to 90% in the thickness direction.

9. The manufacturing method according to claim 7, characterized in that: In the cold rolling process, the rolling reduction in each pass is 2%-6%.

10. The manufacturing method according to any one of claims 7 to 9, characterized in that: In the annealing process, the annealing treatment time is 30 minutes to 50 minutes.

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