A high-nitrogen high-entropy alloy ultra-thin strip, a preparation method thereof and applications thereof

Abstract

The application relates to the technical field of metal ultra-thin strips, in particular to a high-nitrogen high-entropy alloy ultra-thin strip and a preparation method and application thereof. The preparation method comprises the following steps: carrying out multi-pass asynchronous rolling on a high-nitrogen high-entropy alloy with a thickness of 1-10 mm to obtain a high-nitrogen high-entropy alloy ultra-thin strip with a thickness of 40-60 mu m; the number of passes of the multi-pass asynchronous rolling is at least 10 times, the total deformation amount is 94%-99.6%, and the roller speed ratio is 1.5-2.0:1; the high-nitrogen high-entropy alloy is prepared from Fe 46.3%-47.3%, Mn 29.5%-30.5%, Co 9.5%-10.5%, Cr 9.5%-10.5% and N 3%-3.9% in terms of molar percentage. Based on the characteristics of the high-nitrogen high-entropy alloy in improving the rolling ductility of the alloy, the high-nitrogen high-entropy alloy ultra-thin strip with excellent comprehensive mechanical properties is obtained by using the asynchronous rolling method and adjusting the asynchronous rolling parameters.

Description

Technical Field

[0001] This invention relates to the field of ultrathin metal strip technology, and more specifically, to a high-nitrogen, high-entropy alloy ultrathin strip, its preparation method, and its application. Background Technology

[0002] Currently, ultra-thin metal strips have wide and important applications in my country's industrial production and daily life. For example, copper-nickel alloys and nickel-chromium alloys have high resistivity and heat resistance, and their foils are often used to manufacture precision resistors and strain gauges; tungsten and molybdenum materials still have high strength and hardness at high temperatures, and their foils can be used to manufacture heating devices and electron tubes; austenitic stainless steel ultra-thin strips have excellent corrosion resistance, formability, and good comprehensive mechanical properties, and their thin strip products are often used in aerospace, electronic communications, and instrumentation fields.

[0003] Ultra-thin metal strips are typically used as structural and functional integrated materials, and their preparation methods include rolling, strip spinning, and continuous casting and rolling. Among these, rolling has advantages such as high production efficiency, low cost, and superior product performance.

[0004] Currently, commonly used ultra-thin metal strips include ordinary copper-nickel strips, iron-nickel strips, manganese-nickel strips, zinc-nickel strips, and aluminum-nickel strips. However, with the rapid development of ultra-thin metal strips, existing ultra-thin metal strips are struggling to meet increasingly demanding application requirements.

[0005] High-entropy alloys are typically composed of multiple main elements in equimolar or near-equimolar ratios, exhibiting various unique effects such as the high-entropy effect, lattice distortion effect, hysteresis diffusion effect, and cocktail effect. Compared to metallic ultrathin strips, high-entropy alloy ultrathin strips possess superior mechanical properties, corrosion resistance, and thermal stability. These characteristics make high-entropy alloy ultrathin strips promising for broad applications in industries such as electronics, optoelectronics, computers, precision machinery manufacturing, and robotics. Further research is needed on the relevant properties of high-entropy alloy ultrathin strips, indicating a broad research field and enormous development potential.

[0006] Therefore, developing a high-entropy alloy ultrathin strip is of great significance.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The primary objective of this invention is to provide a method for preparing ultra-thin strips of high-nitrogen, high-entropy alloys. Based on the property of improving the rolling ductility of alloys with a high proportion of nitrogen, asynchronous rolling is used to control the asynchronous rolling parameters, thereby obtaining ultra-thin strips of high-nitrogen, high-entropy alloys with excellent comprehensive mechanical properties and low raw material costs, which is beneficial to the development and application of ultra-thin strips of high-entropy alloys.

[0009] The second objective of this invention is to provide an ultrathin strip of high-nitrogen, high-entropy alloy.

[0010] A third objective of this invention is to provide applications of high-nitrogen, high-entropy alloy ultrathin strips in transportation vehicles, power electronic equipment, aerospace, marine engineering, medical devices, precision machinery manufacturing, and robot manufacturing.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0012] This invention first provides a method for preparing ultrathin strips of high-nitrogen, high-entropy alloys, comprising the following steps:

[0013] A high-nitrogen high-entropy alloy with a thickness of 1–10 mm was subjected to multi-pass asynchronous rolling to obtain an ultra-thin strip of high-nitrogen high-entropy alloy with a thickness of 40–60 μm.

[0014] The number of passes in the multi-pass asynchronous rolling is at least 10.

[0015] The total deformation of the multi-pass asynchronous rolling is 94% to 99.6%;

[0016] The speed ratio of the upper roll to the lower roll in the multi-pass asynchronous rolling process is 1.5 to 2.0:1;

[0017] The high-nitrogen, high-entropy alloy is prepared from the following elements in molar percentage: Fe 46.3%–47.3%, Mn 29.5%–30.5%, Co 9.5%–10.5%, Cr 9.5%–10.5%, and N 3%–3.9%.

[0018] Furthermore, in the multi-pass asynchronous rolling process, the deformation amount of each pass in the first to third passes is 19% to 21%, the deformation amount of each pass in the fourth to fifth passes is 9% to 11%, the deformation amount of each pass in the sixth to eighth passes is 4% to 6%, and the deformation amount of each pass in the ninth to tenth and above passes is 1.5% to 3%.

[0019] Furthermore, the linear speed of the upper roll in the multi-pass asynchronous rolling is 42-56 mm / s, and the linear speed of the lower roll is 20-35 mm / s.

[0020] Furthermore, the temperature of the multi-pass asynchronous rolling is 15–35°C.

[0021] Furthermore, the preparation method of the high-nitrogen high-entropy alloy ultrathin strip also includes an annealing step, specifically: annealing the high-nitrogen high-entropy alloy ultrathin strip that has undergone the multi-pass asynchronous rolling at 740-760°C for 2-5 minutes.

[0022] Furthermore, after annealing the high-nitrogen high-entropy alloy ultrathin strip at 740–760°C for 2–5 min, the uniform elongation is ≥9% and the total elongation is ≥10.5%.

[0023] Furthermore, after annealing the high-nitrogen, high-entropy alloy ultrathin strip at 740–760°C for 2–5 min, the yield strength is ≥930 MPa and the tensile strength is ≥1100 MPa.

[0024] Furthermore, the preparation method of the high-nitrogen high-entropy alloy includes: melting raw materials containing Fe, Co, Mn, Cr and N elements to obtain a liquid alloy; casting the liquid alloy to obtain an ingot; and sequentially performing hot forging, hot rolling, solution treatment and cutting on the ingot to obtain the high-nitrogen high-entropy alloy.

[0025] Furthermore, the hot forging temperature is 1050–1130°C.

[0026] Furthermore, the initial temperature of the hot rolling is 1030-1100℃, and the final rolling temperature is 900-1000℃; the hot rolling method includes multi-pass hot rolling, wherein the number of passes in the multi-pass hot rolling is ≥5, the deformation amount of each pass is ≥10%, and the total deformation amount of the multi-pass hot rolling is ≥50%.

[0027] The present invention further provides a high-nitrogen high-entropy alloy ultrathin strip, which is prepared by the same method as the high-nitrogen high-entropy alloy ultrathin strip;

[0028] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip is 40–60 μm;

[0029] The high-nitrogen, high-entropy alloy is composed of the following elements in molar percentages: Fe 46.3%–47.3%, Co 9.5%–10.5%, Mn 29.5%–30.5%, Cr 9.5%–10.5%, and N 3%–3.9%.

[0030] The present invention also provides the application of the aforementioned high-nitrogen high-entropy alloy ultrathin strip in transportation vehicles, power electronic equipment, aerospace, marine engineering, medical devices, precision machinery manufacturing, and robot manufacturing.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The method for preparing high-nitrogen high-entropy alloy ultra-thin strip provided by the present invention is based on the characteristic of improving the rolling ductility of alloys by a high proportion of nitrogen element. By using asynchronous rolling means and controlling the asynchronous rolling parameters of multiple passes, high-nitrogen high-entropy alloy ultra-thin strips with excellent comprehensive mechanical properties and low raw material costs can be obtained. This is conducive to the high-entropy alloy ultra-thin strips playing an important role in fields such as power electronic equipment, aerospace, and marine engineering, and provides strong support for the development of related fields.

[0033] (2) The method for preparing high-nitrogen high-entropy alloy ultra-thin strips provided by the present invention can obtain high-nitrogen high-entropy alloy ultra-thin strips with a thickness of 40-60 μm. After annealing, the ultra-thin strips not only have high yield strength and tensile strength, but also high uniform elongation and total elongation, exhibiting excellent comprehensive mechanical properties. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 Image of the high-nitrogen, high-entropy alloy ultrathin strip prepared in Example 1 of this invention;

[0036] Figure 2 A comparison of the engineering stress-strain curves of the high-nitrogen high-entropy alloy ultrathin strip (referred to as the rolled state) obtained in step (2) of Example 1 provided by the present invention and the high-nitrogen high-entropy alloy ultrathin strip (referred to as the annealed state) obtained in step (3);

[0037] Figure 3 XRD comparison images of the high-nitrogen high-entropy alloy ultra-thin strip (referred to as rolled state) obtained in step (2) of Example 1 provided by the present invention and the high-nitrogen high-entropy alloy ultra-thin strip (referred to as annealed state) obtained after annealing in step (3);

[0038] Figure 4 SEM image of the high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) of Example 1 of the present invention;

[0039] Figure 5 SEM image of the annealed high-nitrogen high-entropy alloy ultrathin strip obtained in step (3) of Example 1 provided by the present invention. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] Unless otherwise specified, in this invention, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0042] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0043] Unless otherwise specified, in this invention, "one or more" or "at least one" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0044] In a first aspect, the present invention provides a method for preparing ultrathin strips of high-nitrogen, high-entropy alloys, comprising the following steps:

[0045] High-nitrogen high-entropy alloys with a thickness of 1–10 mm are subjected to multi-pass asynchronous rolling to obtain ultra-thin strips of high-nitrogen high-entropy alloys with a thickness of 40–60 μm.

[0046] The thickness of the high-nitrogen high-entropy alloy includes, but is not limited to, any one of the following values: 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, or any range between two of them.

[0047] The thickness of the high-nitrogen high-entropy alloy ultrathin strip includes, but is not limited to, any point value or any range between 40μm, 43μm, 45μm, 48μm, 50μm, 52μm, 55μm, 58μm, and 60μm.

[0048] Among them, the high-nitrogen high-entropy alloy undergoes solid solution treatment to homogenize the alloy.

[0049] The number of passes in the multi-pass asynchronous rolling is at least 10, such as 10, 11, 12, 13, 14, 15 or more.

[0050] The total deformation of the multi-pass asynchronous rolling is 94% to 99.6%; including but not limited to point values ​​or ranges between any one of 94%, 94.3%, 94.5%, 94.8%, 95%, 95.3%, 95.5%, 95.8%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.3%, 99.5%, and 99.6%.

[0051] The speed ratio of the upper roll to the lower roll in the multi-pass asynchronous rolling is 1.5 to 2.0:1, including but not limited to any one of 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1 or any range between two of them.

[0052] The high-nitrogen high-entropy alloy is prepared from the following elements in molar percentage: Fe 46.3%–47.3%, Mn 29.5%–30.5%, Co 9.5%–10.5%, Cr 9.5%–10.5%, and N 3%–3.9%. The applicant has found that when the nitrogen content in the high-nitrogen high-entropy alloy is between 3% and 3.9%, the ductility of the high-nitrogen high-entropy alloy is greatly improved.

[0053] The Fe percentage measurement includes, but is not limited to, point values ​​of any one of 46.3%, 46.5%, 46.8%, 47%, 47.1%, and 47.3%, or a range between any two; the Mn percentage measurement includes, but is not limited to, point values ​​of any one of 29.5%, 29.8%, 30%, 30.2%, and 30.5%, or a range between any two; the Co percentage measurement includes, but is not limited to, 9.5%, 9.7%, 9.8%, 10%, and 10.2%. Point values ​​of 10.3% or 10.5% or a range between any two; Cr (calculated as a percentage) including but not limited to point values ​​of 9.5%, 9.8%, 10%, 10.3%, and 10.5% or a range between any two; N (calculated as a percentage) including but not limited to point values ​​of 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, and 3.9% or a range between any two.

[0054] The present invention provides a method for preparing ultra-thin high-nitrogen, high-entropy alloy strips. Based on the property of high nitrogen content improving the rolling ductility of the alloy, and utilizing asynchronous rolling techniques to control multi-pass asynchronous rolling parameters, ultra-thin high-nitrogen, high-entropy alloy strips with excellent comprehensive mechanical properties and low raw material costs can be obtained. This is beneficial for the important role of high-entropy alloy ultra-thin strips in fields such as power electronics equipment, aerospace, and marine engineering. The applications of high-entropy alloy ultra-thin strips will become more widespread, providing strong support for the development of related fields.

[0055] Specifically, this invention involves multi-pass asynchronous rolling of a high-nitrogen high-entropy alloy with a specific composition. Due to the specific addition of interstitial nitrogen (N) atoms in the high-nitrogen high-entropy alloy, the rolling ductility of the alloy is greatly improved while simultaneously enhancing its yield strength, tensile strength, and Vickers hardness, achieving a rolling deformation of up to 99.8%. Based on this, this invention uses multi-pass asynchronous rolling to asynchronously roll a high-nitrogen high-entropy alloy with a thickness of 1–10 mm with a reduction of 94%–99.6%, obtaining an ultra-thin strip of high-nitrogen high-entropy alloy with a thickness of 40–60 μm. After annealing, this ultra-thin strip not only exhibits high yield strength and tensile strength but also high uniform elongation and total elongation, demonstrating excellent comprehensive mechanical properties.

[0056] In some specific embodiments, to further improve the comprehensive mechanical properties of the high-nitrogen, high-entropy alloy ultrathin strip, during the multi-pass asynchronous rolling process, the deformation amount of each pass in the first to third passes (i.e., the first, second, and third passes) is 19% to 21%, including but not limited to any one of 19%, 19.5%, 20%, 20.5%, and 21%, or any range between any two; the deformation amount of each pass in the fourth and fifth passes is 9% to 11%, including but not limited to any one of 9%, 9.5%, 10%, 10.5%, and 11%. The value of one of the points or the range between any two; the rolling deformation of each pass in passes 6 to 8 (i.e., passes 6, 7, and 8) is 4% to 6%, including but not limited to the point value of any one of 4%, 4.5%, 5%, 5.5%, and 6% or the range between any two; the rolling deformation of each pass in passes 9 and 10 and above is 1.5% to 3%, including but not limited to the point value of any one of 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.3%, 2.5%, 2.8%, and 3% or the range between any two. Passes and above refer to passes with 10 or more passes, such as passes 11, 12, 13, and 15.

[0057] In some specific embodiments, to further improve the comprehensive mechanical properties of the high-nitrogen, high-entropy alloy ultrathin strip, the linear speed of the upper roll in the multi-pass asynchronous rolling is 42–56 mm / s, including but not limited to 42 mm / s, 43 mm / s, 44 mm / s, 45 mm / s, 46 mm / s, 47 mm / s, 48 ​​mm / s, 49 mm / s, 50 mm / s, 51 mm / s, 52 mm / s, 53 mm / s, 54 mm / s, 55 mm / s, and 56 mm / s. The linear speed of the lower roll in the multi-pass asynchronous rolling process is 20 to 35 mm / s, including but not limited to the point value of any one of 20 mm / s, 21 mm / s, 22 mm / s, 23 mm / s, 24 mm / s, 25 mm / s, 26 mm / s, 28 mm / s, 30 mm / s, 31 mm / s, 32 mm / s, 33 mm / s, and 35 mm / s, or the range between any two.

[0058] In some specific embodiments, the temperature of the multi-pass asynchronous rolling is 15 to 35°C, including but not limited to any one of 15°C, 18°C, 20°C, 22°C, 23°C, 25°C, 27°C, 28°C, 30°C, 33°C, and 35°C, or any range between two of them.

[0059] In some specific implementations, the multi-pass asynchronous rolling is performed at room temperature.

[0060] In some specific embodiments, to further improve the comprehensive mechanical properties of the high-nitrogen high-entropy alloy ultrathin strip, the preparation method of the high-nitrogen high-entropy alloy ultrathin strip further includes an annealing step, specifically: annealing the high-nitrogen high-entropy alloy ultrathin strip with a thickness of 40-60 μm at 740-760℃ for 2-5 min, followed by quenching. The quenching method includes water cooling, wherein the water cooling is to room temperature, for example, 20-30℃.

[0061] In some specific embodiments, after annealing the high-nitrogen high-entropy alloy ultrathin strip at 740–760°C for 2–5 min, the resulting ultrathin strip has a uniform elongation ≥9% and a total elongation ≥10.5%. The uniform elongation includes, but is not limited to, any one of 9%, 9.2%, 9.5%, 9.8%, 10%, 10.3%, 10.5%, 10.8%, 11%, 11.2%, 11.5%, 11.7%, and 12%, or a range between any two. The total elongation includes, but is not limited to, any one of 10.5%, 10.8%, 11%, 11.2%, 11.4%, 11.5%, 11.7%, 11.9%, 12%, and 12.5%, or a range between any two.

[0062] Uniform elongation refers to the engineering strain value in the tensile curve when the strength reaches its maximum (tensile strength) as loading progresses. Total elongation, also known as maximum elongation, refers to the strain value corresponding to the end of the tensile curve when the material fractures.

[0063] In some specific embodiments, after annealing the high-nitrogen high-entropy alloy ultrathin strip at 740-760℃ for 2-5 minutes, the yield strength of the obtained ultrathin strip is ≥930MPa, including but not limited to any point value or any range between 930MPa, 935MPa, 940MPa, 945MPa, 950MPa, 960MPa, 965MPa, 970MPa, 980MPa, 990MPa, and 1000MPa.

[0064] In some specific embodiments, after annealing the high-nitrogen high-entropy alloy ultrathin strip at 740-760℃ for 2-5 minutes, the resulting ultrathin strip has a tensile strength ≥1100MPa, including but not limited to any one of 1100MPa, 1105MPa, 1110MPa, 1120MPa, 1130MPa, 1140MPa, 1150MPa, 1160MPa, 1170MPa, 1180MPa, 1190MPa, 1195MPa, and 1200MPa, or a range between any two.

[0065] In some specific embodiments, the preparation method of the high-nitrogen high-entropy alloy includes: melting raw materials containing Fe, Co, Mn, Cr and N elements to obtain a liquid alloy; casting the liquid alloy to obtain an ingot; and sequentially subjecting the ingot to hot forging, hot rolling, solution treatment and cutting to obtain the high-nitrogen high-entropy alloy.

[0066] In some specific embodiments, the hot forging temperature is 1050 to 1130°C, including but not limited to any one of 1050°C, 1060°C, 1080°C, 1100°C, 1120°C, and 1130°C, or any range between two of them.

[0067] In some specific embodiments, the initial temperature of the hot rolling is 1030-1100℃, including but not limited to any one of 1030℃, 1040℃, 1050℃, 1060℃, 1080℃, and 1100℃, or any range between two of them; the final rolling temperature of the hot rolling is 900-1000℃, including but not limited to any one of 900℃, 910℃, 920℃, 930℃, 950℃, 960℃, and 980℃, or any range between two of them.

[0068] In some specific embodiments, the hot rolling method includes multi-pass hot rolling, wherein the number of passes is ≥5, including but not limited to point values ​​or ranges between any two of 5, 6, 7, and 8 passes; the deformation of each pass is ≥10%, including but not limited to point values ​​or ranges between any two of 10%, 11%, 12%, 13%, 14%, and 15%; and the total deformation of the multi-pass hot rolling is ≥50%, including but not limited to point values ​​or ranges between any two of 50%, 51%, 52%, 53%, 54%, and 55%. Preferably, the deformation of each pass is >10%, and the total deformation of the multi-pass hot rolling is >50%.

[0069] In some specific embodiments, the raw materials containing Fe, Co, Mn, Cr, and N elements include: pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks, chromium nitride, and manganese nitride alloys, wherein the nitrogen content in the chromium nitride alloy is 10 wt.%, the nitrogen content in the manganese nitride alloy is 14.5 wt.%, and the purity of each of the pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks, and manganese nitride alloys is independently 99.9 wt.%.

[0070] In some specific embodiments, the melting refers to vacuum induction melting in a pressurized vacuum medium-frequency induction furnace. Preferably, the vacuum degree of the melting is 3-5 Pa, the melting temperature is 1650-1750°C, the melting time is 15-30 min, and the melting is performed 4-6 times.

[0071] In some specific embodiments, the casting temperature is 1650-1750℃, the casting time is 80-100s, the casting yields a cylindrical ingot, and the mold used for casting is made of high-temperature alloy steel.

[0072] In some specific embodiments, the hot forging time is 10 to 20 minutes, and the hot forging yields a primary alloy billet with a rectangular cross-section (105 mm × 50 mm). The hot forging is carried out in a box furnace.

[0073] In some specific embodiments, the hot rolling apparatus is: The experimental two-roll (asynchronous) hot rolling mill has a roll diameter of 0.45m.

[0074] In some specific embodiments, the solution treatment is carried out at a temperature of 1150–1250°C for 2–4 hours.

[0075] In some specific embodiments, after the solution treatment is completed, the product after the solution treatment is cooled to obtain a secondary alloy billet, wherein the cooling method is water cooling; the temperature reached by water cooling is room temperature, for example, 20 to 30°C.

[0076] In some specific embodiments, the cutting method includes: using an electrical discharge wire cutting machine to process the solution-treated alloy to a thickness of 1 to 10 mm.

[0077] In some specific implementations, the multi-pass asynchronous rolling is carried out by exchanging the beginning and end of the rolling mill in each pass for meshing.

[0078] In some specific implementations, the multi-pass asynchronous rolling can be performed using any asynchronous rolling mill commonly used in the art, such as a four-roll asynchronous rolling mill, but is not limited thereto.

[0079] Secondly, the present invention provides a high-nitrogen high-entropy alloy ultrathin strip, which is prepared by the above-mentioned method for preparing high-nitrogen high-entropy alloy ultrathin strip.

[0080] The thickness of the high-nitrogen high-entropy alloy ultrathin strip is 40-60 μm; including but not limited to point values ​​or ranges between any one of 40 μm, 43 μm, 45 μm, 48 μm, 50 μm, 52 μm, 55 μm, 58 μm, and 60 μm.

[0081] The high-nitrogen, high-entropy alloy strip prepared by this invention has a small thickness and can be used in fields such as electronics, optoelectronics, computers, precision machinery manufacturing, and robot manufacturing, with broad application prospects.

[0082] The high-nitrogen, high-entropy alloy is composed of the following elements in molar percentage: Fe 46.3%–47.3%, Co 9.5%–10.5%, Mn 29.5%–30.5%, Cr 9.5%–10.5%, and N 3%–3.9%. Specifically, Fe, in molar percentage, includes, but is not limited to, any one of 46.3%, 46.5%, 46.8%, 47%, 47.1%, and 47.3%, or a range between any two; Mn, in molar percentage, includes, but is not limited to, any one of 29.5%, 29.8%, 30%, 30.2%, and 30.5%, or a range between any two; Co, in molar percentage, includes, but is not limited to, 9.5%, 9.7%, 9.8%, 10%, and 10.2%. Point values ​​of 10.3% or 10.5% or a range between any two; Cr (calculated as a percentage) including but not limited to point values ​​of 9.5%, 9.8%, 10%, 10.3%, and 10.5% or a range between any two; N (calculated as a percentage) including but not limited to point values ​​of 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, and 3.9% or a range between any two.

[0083] Thirdly, the present invention also provides applications of the above-mentioned high-nitrogen high-entropy alloy ultrathin strips in transportation vehicles, power electronic equipment, aerospace, marine engineering, medical devices, precision machinery manufacturing, and robot manufacturing.

[0084] High-entropy alloy ultrathin strips combine the advantages of metal ultrathin strips and high-entropy alloys. High-entropy alloys have a variety of special effects, such as high-entropy effect, lattice distortion effect, hysteresis diffusion effect, and cocktail effect. These characteristics make high-entropy alloy ultrathin strips promising for a wide range of applications in industries such as electronics, optoelectronics, computers, precision machinery manufacturing, and robotics manufacturing.

[0085] The high-entropy alloy ultrathin strip provided by this invention has excellent comprehensive mechanical properties and low cost, which is conducive to the high-entropy alloy ultrathin strip playing an important role in fields such as power electronic equipment, aerospace, and marine engineering.

[0086] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0087] Example 1

[0088] The Fe provided in this embodiment 46.8Mn 30 Co 10 Cr 10 N 3.2 The preparation method of ultrathin strips of high-nitrogen high-entropy alloy includes the following steps:

[0089] (1) The raw materials containing Fe, Co, Mn, Cr and N elements are smelted to obtain a liquid alloy. The raw materials containing Fe, Co, Mn, Cr and N elements are: pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks, chromium nitride and manganese nitride alloys, wherein the nitrogen content in the chromium nitride alloy is 10 wt.%, the nitrogen content in the manganese nitride alloy is 14.5 wt.%, and the purity of the pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks and manganese nitride alloys is 99.9 wt.% independently; the amount of raw materials used meets the following molar percentages of Fe, Co, Mn, Cr and N: Fe 46.8%, Mn 30.0%, Co 10.0%, Cr 10.0% and N 3.2%. The melting is carried out in a pressurized vacuum medium-frequency induction furnace under vacuum induction melting; the vacuum degree of melting is 4Pa, the melting temperature is 1700℃, the melting time is 18min, and the melting is performed 5 times.

[0090] The above-mentioned liquid alloy was sequentially cast, hot-forged, hot-rolled, solution-treated, and cut to obtain a high-nitrogen, high-entropy alloy with a thickness of 1 mm. The casting temperature was 1700℃, the casting time was 90 seconds, and a cylindrical ingot was obtained after casting. The mold used for casting was high-temperature alloy steel. The hot-forging temperature was 1100℃, the hot-forging time was 10 minutes, and a rectangular primary alloy billet with a cross-section of 105 mm × 50 mm was obtained after hot forging in a box furnace. The initial hot-rolling temperature was 1050℃, the final rolling temperature was 950℃, and the hot-rolling method was multi-pass hot rolling, with 5 passes. The deformation amount per pass was 10%, and the total deformation amount after hot rolling was 50%. A primary densified alloy billet with a thickness of 20 mm was obtained after hot rolling. The hot rolling equipment was... A two-roll (asynchronous) hot rolling mill was used as the experimental mill, with roll diameters of 0.45 m. The solution treatment temperature was 1200℃, and the treatment time was 2 hours. After solution treatment, the product was cooled to obtain a secondary alloy billet using water cooling at room temperature (25℃). The solution-treated alloy was then machined to a thickness of 1 mm using a wire EDM machine.

[0091] (2) The high-nitrogen high-entropy alloy with a thickness of 1 mm obtained in step (1) is subjected to multi-pass asynchronous rolling to obtain a high-nitrogen high-entropy alloy ultra-thin strip with a thickness of 50 μm. The multi-pass asynchronous rolling process is carried out at room temperature (25℃) and consists of 10 passes. The deformation amount per pass is 20% for the first to third passes, 10% for the fourth and fifth passes, 4% for the sixth to eighth passes, and 1.5% for the ninth and tenth passes. The total deformation amount is controlled to be 95%. The multi-pass asynchronous rolling process uses a method of exchanging the plates at the beginning and end of each pass before they are fed into the mill for meshing. The linear speed of the upper roll is 49 mm / s, and the linear speed of the lower roll is 28 mm / s. The speed ratio of the upper roll to the lower roll is 1.75:1. The multi-pass asynchronous rolling device is a four-roll asynchronous rolling mill from Northeastern University.

[0092] The yield strength, tensile strength, uniform elongation and total elongation of the high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) were tested to be 1905 MPa, 1921 MPa, 0.2% and 1.5%, respectively.

[0093] (3) The high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) is subjected to short-time annealing treatment. The annealing temperature is 750℃ and the annealing holding time is 3min. Then, it is quenched by water cooling to a temperature of room temperature of 25℃.

[0094] The high-nitrogen high-entropy alloy ultrathin strip obtained after annealing in step (3) was tested and found to have yield strength, tensile strength, uniform elongation and total elongation of 950 MPa, 1119 MPa, 11.3% and 11.5% respectively, showing excellent comprehensive mechanical properties.

[0095] like Figure 1 The image shown is a physical picture of the high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) of this embodiment.

[0096] like Figure 2 The figure shows a comparison of the engineering stress-strain curves of the high-nitrogen high-entropy alloy ultra-thin strip obtained in step (2) of this embodiment (referred to as the rolled state) and the high-nitrogen high-entropy alloy ultra-thin strip obtained in step (3) (referred to as the annealed state). It can be seen that the tensile mechanical properties of the two are compared.

[0097] like Figure 3 The image shows a comparison of the XRD patterns of the high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) of this embodiment (referred to as the rolled state) and the high-nitrogen high-entropy alloy ultrathin strip obtained in step (3) after annealing (referred to as the annealed state). It can be seen that both are composed of a single-phase austenite structure and some precipitates.

[0098] like Figure 4 The image shown is a SEM image of the high-nitrogen, high-entropy alloy ultrathin strip (referred to as the rolled state) obtained in step (2) of this embodiment. Figure 5 The image shown is an SEM image of the annealed high-nitrogen high-entropy alloy ultrathin strip (referred to as annealed state) obtained in step (3) of this embodiment. It can be seen that the rolled state plate contains strip-shaped deformed structures, while the annealed state plate exhibits fine equiaxed crystal structures.

[0099] Example 2

[0100] The Fe provided in this embodiment 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of ultrathin strips of high-nitrogen, high-entropy alloy includes the following steps:

[0101] (1) is basically the same as step (1) in Example 1, except that: the solid solution alloy obtained after solid solution treatment is processed to a thickness of 5mm using an electric wire EDM machine.

[0102] (2) The high-nitrogen high-entropy alloy with a thickness of 5 mm obtained in step (1) is subjected to multi-pass asynchronous rolling to obtain a high-nitrogen high-entropy alloy ultra-thin strip with a thickness of 55 μm. The multi-pass asynchronous rolling process was carried out at room temperature (25℃) and consisted of 10 passes. The deformation amount per pass was 21% for the first to third passes, 10% for the fourth and fifth passes, 4% for the sixth to eighth passes, and 2% for the ninth and tenth passes. The total deformation amount was controlled to be 99%. The multi-pass asynchronous rolling process involved exchanging the plates at the beginning and end of each pass before they were fed into the mill for meshing. The linear speed of the upper roll was 48 mm / s, and the linear speed of the lower roll was 32 mm / s. The speed ratio of the upper roll to the lower roll was 1.5:1. The multi-pass asynchronous rolling equipment was a four-roll asynchronous mill from Northeastern University.

[0103] (3) The high-nitrogen high-entropy alloy ultra-thin strip obtained in step (2) is subjected to short-time annealing treatment. The annealing temperature is 740℃ and the annealing holding time is 4min. Then, it is quenched by water cooling to a room temperature of 25℃.

[0104] Example 3

[0105] The Fe provided in this embodiment 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of ultrathin strips of high-nitrogen, high-entropy alloys includes the following steps:

[0106] (1) is basically the same as step (1) in Example 1, except that: the solid solution alloy obtained after solid solution treatment is processed to a thickness of 10mm using an electric wire EDM machine.

[0107] (2) The high-nitrogen high-entropy alloy with a thickness of 10 mm obtained in step (1) is subjected to multi-pass asynchronous rolling to obtain a high-nitrogen high-entropy alloy ultra-thin strip with a thickness of 45 μm. The multi-pass asynchronous rolling process was carried out at room temperature (25℃) and consisted of 11 passes. The deformation per pass was 19% for the first to third passes, 9% for the fourth and fifth passes, 6% for the sixth to eighth passes, and 2% for the ninth to eleventh passes. The total deformation was controlled to be 99%. The process involved exchanging the plates at the beginning and end of each pass before they were fed into the mill. The linear speed of the upper roll was 54 mm / s, and the linear speed of the lower roll was 30 mm / s. The speed ratio of the upper roll to the lower roll was 1.8:1. The multi-pass asynchronous rolling was performed using a four-roll asynchronous mill from Northeastern University.

[0108] (3) The high-nitrogen high-entropy alloy ultrathin strip obtained in step (2) is subjected to short-time annealing treatment. The annealing temperature is 760℃ and the annealing holding time is 2min. Then, it is quenched by water cooling to a room temperature of 25℃.

[0109] Example 4

[0110] The Fe provided in this embodiment 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 1, except that in step (2), the deformation amount of each rolling pass in the first to third passes is 20%, the deformation amount of each rolling pass in the fourth to fifth passes is 10%, the deformation amount of each rolling pass in the sixth to eighth passes is 4%, and the deformation amount of each rolling pass in the ninth to tenth passes is 2%, and the total deformation amount of the multi-pass asynchronous rolling is finally controlled to be 96%.

[0111] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this embodiment is 40 μm.

[0112] Example 5

[0113] The Fe provided in this embodiment 46.8 Mn 30 Co 10 Cr 10 N3.2 The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 1, except that: in step (2), the linear speed of the upper roll in the multi-pass asynchronous rolling is 45 mm / s, the linear speed of the lower roll is 28 mm / s, and the speed ratio of the upper roll to the lower roll is 1.6:1.

[0114] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this embodiment is 60 μm.

[0115] Example 6

[0116] The Fe provided in this embodiment 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 1, except that in step (2), the linear speed of the upper roll in the multi-pass asynchronous rolling is 53 mm / s, the linear speed of the lower roll is 28 mm / s, and the speed ratio of the upper roll to the lower roll is 1.9:1.

[0117] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this embodiment is 40 μm.

[0118] Example 7

[0119] The Fe provided in this embodiment 465 Mn 295 Co 105 Cr 10 N 35 The preparation method of ultrathin strips of high-nitrogen, high-entropy alloys includes the following steps:

[0120] (1) The raw materials containing Fe, Co, Mn, Cr and N elements are smelted to obtain a liquid alloy. The raw materials containing Fe, Co, Mn, Cr and N elements are: pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks, chromium nitride and manganese nitride alloys, wherein the nitrogen content in the chromium nitride alloy is 10 wt.%, the nitrogen content in the manganese nitride alloy is 14.5 wt.%, and the purity of the pure iron blocks, pure cobalt blocks, pure manganese blocks, pure chromium blocks and manganese nitride alloys is 99.9 wt.% independently; the amount of raw materials used meets the following molar percentages of the elements Fe, Co, Mn, Cr and N: Fe 46.5%, Mn 29.5%, Co 10.5%, Cr 10.0% and N 3.5%. The melting is carried out in a pressurized vacuum medium-frequency induction furnace under vacuum induction melting; the vacuum degree of melting is 5Pa, the melting temperature is 1750℃, the melting time is 20min, and the melting is carried out 5 times.

[0121] The above-mentioned liquid alloy was sequentially cast, hot-forged, hot-rolled, solution-treated, and cut to obtain a high-nitrogen, high-entropy alloy with a thickness of 1 mm. The casting temperature was 1730℃, the casting time was 90 seconds, and a cylindrical ingot was obtained after casting. The mold used for casting was high-temperature alloy steel. The hot-forging temperature was 1130℃, the hot-forging time was 10 minutes, and a rectangular primary alloy billet with a cross-section of 105 mm × 50 mm was obtained after hot forging in a box furnace. The initial hot-rolling temperature was 1100℃, the final rolling temperature was 900℃, and the hot-rolling method was multi-pass hot rolling, with 5 passes. The deformation amount per pass was 11%, and the total deformation amount after hot rolling was 55%. A primary densified alloy billet with a thickness of 40 mm was obtained after hot rolling. The hot rolling equipment was... A two-roll (asynchronous) hot rolling mill was used as the experimental mill, with roll diameters of 0.45 m. The solution treatment temperature was 1230℃, and the treatment time was 3 hours. After solution treatment, the product was cooled to obtain a secondary alloy billet using water cooling at room temperature (25℃). The solution-treated alloy was then machined to a thickness of 2 mm using a wire EDM machine.

[0122] (2) The high-nitrogen high-entropy alloy with a thickness of 2 mm obtained in step (1) is subjected to multi-pass asynchronous rolling to obtain a high-nitrogen high-entropy alloy ultra-thin strip with a thickness of 45 μm. The multi-pass asynchronous rolling process is carried out at room temperature (25℃) and consists of 10 passes. The deformation amount per pass is 20% for the first to third passes, 10% for the fourth and fifth passes, 4% for the sixth to eighth passes, and 3% for the ninth and tenth passes. The total deformation amount is controlled to be 98%. The multi-pass asynchronous rolling process uses a method of exchanging the plates at the beginning and end of each pass before they are fed into the mill for meshing. The linear speed of the upper roll is 56 mm / s, and the linear speed of the lower roll is 28 mm / s. The speed ratio of the upper roll to the lower roll is 2:1. The multi-pass asynchronous rolling device is a four-roll asynchronous mill from Northeastern University.

[0123] (3) The high-nitrogen high-entropy alloy ultra-thin strip obtained in step (2) is subjected to short-time annealing treatment. The annealing temperature is 740℃ and the annealing holding time is 4min. Then, it is quenched by water cooling to a room temperature of 25℃.

[0124] Example 8

[0125] The Fe provided in this embodiment 46.5 Mn 29.5 Co 10.5 Cr 9.7 N 3.8The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 7, except that in step (1), the amount of raw materials used meets the following requirements: the molar percentage of Fe, Co, Mn, Cr and N is: Fe 46.5%, Mn 29.5%, Co 10.5%, Cr 9.7% and N 3.8%.

[0126] Comparative Example 1

[0127] The Fe provided in this comparative example 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 1, except that: in step (2), the number of passes of multi-pass asynchronous rolling is 9, the deformation amount of each pass in the first and second passes is 20%, the deformation amount of each pass in the third and fourth passes is 10%, the deformation amount of each pass in the fifth and seventh passes is 4%, and the deformation amount of each pass in the eighth and ninth passes is 2%, and the total deformation amount of multi-pass asynchronous rolling is finally controlled to be 76%.

[0128] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this comparative example is 240 μm.

[0129] Comparative Example 2

[0130] The Fe provided in this comparative example 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of the high-nitrogen high-entropy alloy ultrathin strip is basically the same as that in Example 1, except that: in step (2), the linear speed of the upper roll of the multi-pass asynchronous rolling is 84 mm / s, the linear speed of the lower roll is 28 mm / s, and the speed ratio of the upper roll to the lower roll is 3.0:1.

[0131] Comparative Example 3

[0132] The Fe provided in this comparative example 48 Mn 30 Co 10 Cr 10 The preparation method of N2 alloy ultrathin strip is basically the same as that in Example 1, except that: in step (1), the amount of raw materials used meets the following requirements: the molar percentage of Fe, Co, Mn, Cr and N contained in the raw materials is: Fe 48%, Mn 30%, Co 10%, Cr 10% and N2.

[0133] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this comparative example is 200 μm.

[0134] Comparative Example 4

[0135] The Fe provided in this comparative example 46.8 Mn 30 Co 10 Cr 10 N 3.2 The preparation method of the alloy ultrathin strip is basically the same as that in Example 1, except that: no cutting is performed in step (1), that is, in step (2), a high nitrogen high entropy alloy with a thickness of 20 mm is directly used for multi-pass asynchronous rolling.

[0136] The thickness of the high-nitrogen, high-entropy alloy ultrathin strip prepared in this comparative example is 80 μm.

[0137] Experimental Example

[0138] Referring to standard GB / T 228.1—2010, the uniform elongation, total elongation, yield strength and tensile strength of the high-nitrogen high-entropy alloy ultrathin strips prepared in each embodiment and each comparative example were measured after annealing. The results are shown in Table 1.

[0139] The calculation methods for uniform elongation and total elongation are as follows: On the force-elongation curve obtained by the extensometer, the elastic elongation is subtracted from the total elongation at maximum force to obtain the plastic elongation at maximum force, and then divided by the extensometer gauge length to obtain the uniform elongation; On the force-elongation curve obtained by the extensometer, the elastic elongation is subtracted from the total elongation at fracture to obtain the plastic elongation at fracture, and then divided by the extensometer gauge length to obtain the total elongation.

[0140] The yield strength is calculated as follows: On the force-elongation curve, draw a line parallel to the elastic straight line segment of the curve, with the distance between this line segment and the elongation axis equivalent to the specified plastic elongation, i.e., 0.2%. The intersection of this parallel line and the curve gives the force corresponding to the yield strength. Dividing this force by the original cross-sectional area of ​​the specimen yields the yield strength.

[0141] The tensile strength is calculated as follows: On the force-elongation curve, draw a line parallel to the force axis and whose distance from the axis is equivalent to the uniform elongation. The intersection of this line with the curve gives the force corresponding to the tensile strength. Divide this force by the original cross-sectional area of ​​the specimen to obtain the tensile strength.

[0142] Table 1. Elongation and mechanical properties of various ultrathin strips

[0143] Example 1 11.3％ 11.5％ 950 1119 Example 2 9.4％ 10.8％ 985 1180 Example 3 9.2％ 10.5％ 996 1195 Example 4 11.0％ 11.4％ 977 1156 Example 5 11.5％ 11.9％ 930 1107 Example 6 10.8％ 11.2％ 965 1130 Example 7 10.9％ 11.3％ 978 1185 Example 8 10.6％ 11.1％ 989 1210 Comparative Example 1 19.4％ 23.0％ 840 927 Comparative Example 2 5.3％ 6.7％ 963 1125 Comparative Example 3 7.9％ 9.1％ 782 951 Comparative Example 4 8.5％ 9.2％ 945 1100

[0144] As can be seen from Table 1, the high-nitrogen, high-entropy alloy ultrathin strips prepared in the various embodiments of the present invention have excellent comprehensive mechanical properties.

[0145] In contrast, Comparative Example 1 could not be made into an extremely thin metal strip due to insufficient asynchronous rolling passes and insufficient total deformation (the thickness was too large).

[0146] In Comparative Example 2, the surface quality of the thin strip material was significantly reduced due to the excessively high roller speed ratio.

[0147] Comparative Example 3 had insufficient rolling elongation due to its low nitrogen content, which prevented the production of thin strip materials (due to excessive thickness).

[0148] Comparative Example 4, due to the lack of cutting, directly used a high-nitrogen high-entropy alloy with a thickness of 20mm for multi-pass asynchronous rolling, resulting in the alloy material being rolled to a final thickness of only 80μm, which is relatively thick.

[0149] In summary, the preparation method of high-nitrogen high-entropy alloy ultrathin strips provided by this invention can obtain high-nitrogen high-entropy alloy ultrathin strips with excellent comprehensive mechanical properties, which can meet the application requirements of high-entropy alloy ultrathin strips, make the application of high-entropy alloy ultrathin strips more extensive, and provide strong support for the development of related fields.

[0150] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing ultrathin strips of high-nitrogen, high-entropy alloys, characterized in that, Includes the following steps: A high-nitrogen high-entropy alloy with a thickness of 1~10 mm was subjected to multi-pass asynchronous rolling to obtain an ultra-thin strip of high-nitrogen high-entropy alloy with a thickness of 40~60 μm. The number of passes in the multi-pass asynchronous rolling is at least 10. The total deformation of the multi-pass asynchronous rolling process is 94%~99.6%; The speed ratio of the upper roll to the lower roll in the multi-pass asynchronous rolling process is 1.5~2.0:1; The high-nitrogen, high-entropy alloy is prepared from the following elements in molar percentage: Fe 46.3%~47.3%, Mn 29.5%~30.5%, Co 9.5%~10.5%, Cr 9.5%~10.5%, and N 3%~3.9%; In the multi-pass asynchronous rolling process, the deformation amount of each pass in the 1st to 3rd passes is 19% to 21%, the deformation amount of each pass in the 4th to 5th passes is 9% to 11%, the deformation amount of each pass in the 6th to 8th passes is 4% to 6%, and the deformation amount of each pass in the 9th to 10th and above passes is 1.5% to 3%. The linear speed of the upper roll in the multi-pass asynchronous rolling process is 42~56 mm / s, and the linear speed of the lower roll is 20~35 mm / s. The temperature of the multi-pass asynchronous rolling is 15~35℃.

2. The method for preparing the high-nitrogen, high-entropy alloy ultrathin strip according to claim 1, characterized in that, The preparation method of the high-nitrogen high-entropy alloy ultrathin strip also includes an annealing step, specifically: annealing the high-nitrogen high-entropy alloy ultrathin strip that has undergone the multi-pass asynchronous rolling at 740~760 ℃ for 2~5 min.

3. The method for preparing high-nitrogen, high-entropy alloy ultrathin strips according to claim 2, characterized in that, After annealing the high-nitrogen, high-entropy alloy ultrathin strip at 740-760 °C for 2-5 min, the uniform elongation is ≥9% and the total elongation is ≥10.5%.

4. The method for preparing the high-nitrogen, high-entropy alloy ultrathin strip according to claim 2, characterized in that, After annealing the high-nitrogen, high-entropy alloy ultrathin strip at 740-760 °C for 2-5 min, the yield strength is ≥930 MPa and the tensile strength is ≥1100 MPa.

5. The method for preparing high-nitrogen, high-entropy alloy ultrathin strips according to claim 1, characterized in that, The preparation method of the high-nitrogen high-entropy alloy includes: melting raw materials containing Fe, Co, Mn, Cr and N elements to obtain a liquid alloy; casting the liquid alloy to obtain an ingot; and sequentially performing hot forging, hot rolling, solution treatment and cutting on the ingot to obtain the high-nitrogen high-entropy alloy.

6. The method for preparing the high-nitrogen, high-entropy alloy ultrathin strip according to claim 5, characterized in that, The hot forging temperature is 1050~1130 ℃.

7. The method for preparing the high-nitrogen, high-entropy alloy ultrathin strip according to claim 5, characterized in that, The initial temperature of the hot rolling is 1030~1100 ℃, and the final rolling temperature is 900~1000 ℃.

8. The method for preparing the high-nitrogen, high-entropy alloy ultrathin strip according to claim 5, characterized in that, The hot rolling method includes multi-pass hot rolling, wherein the number of passes in the multi-pass hot rolling is ≥5, the deformation of each pass is ≥10%, and the total deformation of the multi-pass hot rolling is ≥50%.

9. A high-nitrogen, high-entropy alloy ultrathin strip, characterized in that, It is prepared by the method for preparing high-nitrogen high-entropy alloy ultrathin strips according to any one of claims 1 to 8; The thickness of the high-nitrogen, high-entropy alloy ultrathin strip is 40-60 μm. The high-nitrogen, high-entropy alloy is composed of the following elements in molar percentages: Fe 46.3%~47.3%, Co 9.5%~10.5%, Mn 29.5%~30.5%, Cr 9.5%~10.5% and N 3%~3.9%.

10. The application of the high-nitrogen, high-entropy alloy ultrathin strip as described in claim 9 in transportation vehicles, power electronic equipment, aerospace, marine engineering, medical devices, precision machinery manufacturing, and robot manufacturing.

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