Fe-Mn high-entropy alloys, plates and their preparation methods

Abstract

This invention discloses a method for preparing Fe-Mn high-entropy alloys, comprising the following steps: raw materials Fe, Mn, Co, Cr, Mo, and FeC are proportioned according to an atomic ratio of Fe:Mn:Co:Cr:C:Mo of 45~50:28~29.5:9~10:9~10:2~2.1:0.8~1.2; the above raw materials are fed into a vacuum arc melting furnace and subjected to arc melting under an inert gas atmosphere to obtain button ingots; the button ingot alloy is then melted again and poured into a plate mold to obtain a cast Fe-Mn high-entropy alloy; this invention also discloses Fe-Mn high-entropy alloys, Fe-Mn high-entropy alloy plates, and their preparation methods; the high-entropy alloy prepared by this invention has a single-phase FCC structure, with a total elongation of up to 110%~120%, and a tensile strength still maintained at 800MPa~810MPa, and a strength-ductility product as high as 90GPa%~95GPa.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical method technology, and relates to a method for preparing Fe-Mn high-entropy alloys. This invention also relates to Fe-Mn high-entropy alloys, a method for preparing Fe-Mn high-entropy alloy plates, and Fe-Mn high-entropy alloy plates. Background Technology

[0002] High-entropy alloys, as a new type of metallic material, are defined by containing five or more main elements, with each element having an atomic percentage ranging from 5% to 35%. Due to their high configurational entropy, these alloys preferentially form stable solid solution microstructures, effectively avoiding the formation of complex intermetallic compounds. This unique structure endows high-entropy alloys with excellent comprehensive properties, making them promising for applications in various industrial fields. Metastable two-phase Fe 50 Mn 30 Co 10 Cr 10 High-entropy alloys are a new type of material developed in recent years. These alloy systems have low stacking fault energy, unstable phase structures, and deformation easily triggers transformation-induced plasticity (TRIP) and twin-induced plasticity (TWIP) effects, thus overcoming the strength-ductility balance of metallic materials. They represent a promising new type of high-entropy alloy. However, existing Fe... 50 Mn 30 Co 10 Cr 10 The strength of high-entropy alloys is not outstanding and needs further improvement.

[0003] To improve the strength of high-entropy alloys, researchers typically employ methods such as solid solution strengthening, second-phase strengthening (e.g., carbides, intermetallic compounds), or grain refinement. For example, adding carbon (C) to achieve strengthening through interstitial solid solution and carbide formation is a common technique. Related research can be found in several academic papers, such as "Interstitialequiatomic CoCrFeMnNi high-entropy alloys: carbon content, microstructure, and compositional homogeneity effects on deformation behavior" (Acta Materialia, 2019, Vol. 166, pp. 334-348), which explores the influence of carbon on the microstructure and deformation behavior of CoCrFeMnNi high-entropy alloys. However, simply adding carbon, while increasing strength, often leads to a significant decrease in material plasticity, resulting in the common contradiction of a "reverse" strength and plasticity. In addition, the addition of molybdenum (Mo) has been studied to improve the strength and corrosion resistance of alloys, but its effect on plasticity needs to be carefully balanced. Furthermore, high-entropy alloys generally have the problem of high work hardening rate and difficulty in plastic rolling.

[0004] In terms of material morphology, preparing high-entropy alloys into sheets and endowing them with excellent comprehensive mechanical properties is key to promoting their engineering applications. In existing technologies, the preparation of high-entropy alloy sheets often involves complex multi-stage thermomechanical processing, and the product of strength and plasticity (strength-ductility product) of the final sheet still has significant room for improvement. Strength-ductility product is an important indicator for measuring the comprehensive mechanical properties of a material; a high strength-ductility product means that the material possesses both high strength and high plasticity, which is crucial for subsequent manufacturing processes such as stamping of complex parts. Therefore, the main problems in existing technologies are: traditional and improved high-entropy alloys struggle to simultaneously achieve a match between ultra-high strength and ultra-high plasticity, and their strength-ductility product needs further improvement; simultaneously, the comprehensive mechanical properties (especially the strength-ductility product) of the sheets obtained by existing preparation processes are often insufficient to provide an ideal base material for the direct forming of complex parts. From currently published patents, there are few patents that achieve ultra-high strength-ductility product by fine-tuning the alloy composition and using different processing techniques; most only improve mechanical properties through optimization of processing techniques. Patent CN117385260B discloses an ultra-high strength-ductility product Fe... 50 Mn 30 Co 10 Cr 10The alloy preparation method, under this process, produces high-entropy alloys with tensile strengths of 1050–1280 MPa, elongation of 35%–58%, and strength-ductility product of 40–73 GPa. While the strength is indeed improved, the elongation loss is significant, resulting in a low overall strength-ductility product. Patent CN110284042B also discloses a method for improving Fe content through the use of C and Mo elements. 50 Mn 25 Co 10 Cr 15 Microalloying of the alloy, followed by specific processing techniques, yields superplastic high-entropy alloy sheets. Furthermore, through appropriate processing and manufacturing methods, the grain size of the alloy is further refined, resulting in increased strength. In Fe... 50 Mn 30 Co 10 Cr 10 There is limited research on the plastic rolling of high-entropy alloys after alloying with C and Mo elements. In summary, existing technologies are still insufficient in preparing ultra-high strength and plasticity Fe-Mn high-entropy alloys. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing Fe-Mn high-entropy alloys, which solves the problem in existing technologies that it is difficult to simultaneously achieve a balance between ultra-high strength and ultra-high plasticity in high-entropy alloys.

[0006] The second objective of this invention is to provide Fe-Mn based high-entropy alloys.

[0007] The third objective of this invention is to provide a method for preparing Fe-Mn-based high-entropy alloy plates.

[0008] The fourth objective of this invention is to provide Fe-Mn based high-entropy alloy plates.

[0009] The first technical solution adopted in this invention is a method for preparing Fe-Mn high-entropy alloys, comprising the following steps:

[0010] Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo and FeC according to the atomic ratio Fe:Mn:Co:Cr:C:Mo of 45~50:28~29.5:9~10:9~10:2~2.1:0.8~1.2; Step 2: Put the above raw materials into a vacuum electric arc melting furnace and carry out electric arc melting in an inert gas atmosphere to obtain button ingots; Step 3: Remelt the button ingot alloy and pour it into a plate mold to obtain a cast Fe-Mn high-entropy alloy.

[0011] The first technical solution of this invention is also characterized by: In step 1, the purity of the raw materials Fe, Mn, Co, Cr, Mo and FeC is not less than 99.9%.

[0012] Step 2 is performed as follows: Step 2.1: Load the raw materials Fe, Mn, Co, Cr, Mo, and FeC into a vacuum arc melting furnace, and evacuate the furnace cavity to a vacuum level of 2.5 × 10⁻⁶. -3 Pa ~ 3.5 × 10 -3 Pa; Step 2.2: Inject argon gas into the vacuum arc melting furnace until its internal pressure is not higher than -0.5 Pa and the argon gas concentration is not lower than 99.99 wt%. Step 2.3: Place titanium ingots with a purity of not less than 99.95% in one crucible in a vacuum arc melting furnace, and place the remaining raw materials in another crucible in the vacuum arc melting furnace to melt the titanium ingots into a liquid state. Step 2.4: continuously melt the raw materials at a temperature of not less than 1368℃ until they are completely melted into a liquid state and then obtain button ingots in the mold. Each button ingot is turned over and melted at least five times, with each melting lasting 3 to 5 minutes. Take a sample when the raw materials have cooled to room temperature. Electromagnetically stir the alloy melt during the melting process, but do not perform electromagnetic stirring during the first and last melting.

[0013] The second technical solution adopted in this invention is a Fe-Mn high-entropy alloy prepared by a method for preparing Fe-Mn high-entropy alloys.

[0014] The third technical solution adopted in this invention is a method for preparing Fe-Mn high-entropy alloy plates, comprising the following steps: Step a: Hot-roll the Fe-Mn high-entropy alloy and cool it at room temperature to obtain a hot-rolled plate; Step b: Perform solution treatment on the hot-rolled plate; Step c: The solution-treated sheet is cold-rolled to obtain a cold-rolled sheet; Step d: The cold-rolled sheet is annealed and water-quenched sequentially to obtain Fe-Mn high-entropy alloy sheet. The third technical solution of this invention is further characterized by: Step a specifically involves hot rolling the Fe-Mn high-entropy alloy at 900~950℃ using a rolling mill for no less than 30 passes, with a total reduction of 25%~30% and a strain of no more than 4% per pass, followed by cooling at room temperature to obtain a hot-rolled plate.

[0015] Step b specifically involves placing the hot-rolled plate in a resistance box heating furnace and heating it to 1180℃~1250℃, then holding it at that temperature for 1h~2h.

[0016] Step c specifically involves: subjecting the solution-treated sheet to cold rolling at room temperature for no less than 40 passes, with a cold rolling deformation of 60% to 70% and a strain of no more than 4% per pass.

[0017] The annealing process is as follows: using argon gas with a purity of not less than 99.95% as a protective gas, the furnace is heated to 1000℃~1050℃ and held for 3min~5min.

[0018] The fourth technical solution adopted in this invention is an Fe-Mn high-entropy alloy plate prepared by a method for preparing Fe-Mn high-entropy alloy plates.

[0019] The beneficial effects of this invention are: This invention obtains a novel Fe-Mn high-entropy alloy by adjusting the content of high-entropy alloying elements through batching, electric arc vacuum melting, and casting. Further hot rolling, heat treatment, cold rolling, annealing, and quenching are then performed on the alloy to obtain Fe-Mn alloy plates with uniform grain size, a single-phase FCC structure, and ultra-high strength-ductility product. This provides a material basis for the forming of complex parts. After performance testing, the alloy exhibits a total elongation of up to 110%~120%, while maintaining a tensile strength of 800MPa~810MPa and a strength-ductility product of 90GPa%~95GPa. Attached Figure Description

[0020] Figure 1 This is the XRD pattern of the Fe-Mn high-entropy alloy in the cast state of Example 1 of this invention; Figure 2 This is a SEM image of the Fe-Mn high-entropy alloy in the cast state of Example 1 of this invention; Figure 3 This is a tensile property diagram of the Fe-Mn high-entropy alloy in the cast state of Example 1 of this invention; Figure 4 This is the XRD pattern of the Fe-Mn high-entropy alloy plate from Example 4 of this invention; Figure 5 This is a SEM image of the Fe-Mn high-entropy alloy sheet after stretching in Example 4 of this invention; Figure 6 This is a tensile property diagram of the Fe-Mn high-entropy alloy sheet from Example 4 of this invention. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] The preparation method of Fe-Mn high-entropy alloys includes the following steps: Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo, and FeC according to the atomic ratio Fe:Mn:Co:Cr:C:Mo of 45~50:28~29.5:9~10:9~10:2~2.1:0.8~1.2. The purity of Fe, Mn, Co, Cr, Mo, and FeC shall not be less than 99.9%. Step 2: The raw materials Fe, Mn, Co, Cr, Mo, and FeC are loaded into a vacuum arc melting furnace. A mechanical pump is used to pre-evacuate the furnace to 7.5 Pa–8.5 Pa. Then, the shut-off valve is opened to evacuate the furnace to 5.5 Pa–6.5 Pa. Finally, a molecular pump is used to evacuate the furnace cavity to a vacuum of 2.5 × 10⁻⁶ Pa. -3 Pa ~ 3.5 × 10 -3 Pa, inject argon gas into the vacuum arc melting furnace until its internal pressure is not higher than -0.5 Pa and the argon concentration is not lower than 99.99 wt%. Place titanium ingots with a purity of not less than 99.95% in one crucible in the vacuum arc melting furnace, and place the remaining raw materials in another crucible in the vacuum arc melting furnace. Melt the titanium ingots to a liquid state, thereby adsorbing O2, N2, H2, CO, CO2, and CH4 gases. Continue to melt the raw materials at a melting temperature of not less than 1368℃ until they are completely melted into a liquid state. Obtain button ingots in a mold. Turn each button ingot over and melt it at least five times, with each melting lasting 3 to 5 minutes. Take a sample when the raw materials cool to room temperature to obtain high-entropy alloy ingots. Electromagnetically stir the alloy melt during the melting process, but do not perform electromagnetic stirring during the first and last melting. Step 3: Remelt the button ingot alloy and pour it into a 90mm diameter ingot. In a 30mm thick, 8mm-10mm plate mold, a cast Fe-Mn high-entropy alloy is obtained. During casting, the material has a large contact area with the mold and a fast cooling rate during solidification, resulting in a dense structure with fine grains and a cast plate with few defects.

[0023] When the raw materials are added to the vacuum arc melting furnace, the surface will be partially oxidized, so it is necessary to ensure that the purity is not less than 99.9%. The raw materials initially added to the vacuum arc melting furnace are metal particles. Direct electromagnetic stirring will cause the raw materials to splash, which will change the raw material ratio. The last stirring is basically uniform and no further stirring is required.

[0024] The present invention also provides Fe-Mn high-entropy alloys, which are prepared by the above-described method for preparing Fe-Mn high-entropy alloys.

[0025] The preparation method of Fe-Mn high-entropy alloy plates includes the following steps: Step a: The Fe-Mn high-entropy alloy is hot-rolled at 900~950℃ using a rolling mill for no less than 30 passes, with a total reduction of 25%~30% and a strain of no more than 4% per pass. The hot-rolled plate is obtained by cooling at room temperature. The purpose of hot rolling is to press together the shrinkage cavities and porosity remaining in the cast alloy so that the plate will not crack due to the original defects of the material when subjected to high stress. Step b: Place the hot-rolled plate in a resistance box furnace and heat it to 1180℃~1250℃ with the furnace, and hold it for 1h~2h. The selection of this temperature is obtained by differential thermal analysis of the alloy. At this temperature, the alloy can be guaranteed to have a uniform face-centered cubic single-phase structure without change. At the same time, the solution treatment can also obtain a completely homogenized structure, effectively softening the alloy structure and preventing cold rolling cracking during the next large deformation. Step c: The solution-treated sheet is cold-rolled at room temperature for no less than 40 passes, with a cold rolling deformation of 60% to 70% and a strain of no more than 4% per pass. To avoid excessive deformation that could cause the alloy sheet to crack, the strain per pass should be as small as possible. The purpose of cold rolling is to further refine the grains of the alloy, introduce multiple grain boundaries and subgrain boundaries, effectively ensure the plasticity of the alloy, harden the alloy, and make the alloy structure more uniform and dense. Step d: Anneal the cold-rolled sheet using argon gas with a purity of not less than 99.95% as a protective gas. Heat the sheet in the furnace to 1000℃~1050℃ and hold for 3min~5min. This effectively removes the stress introduced during the cold rolling deformation process and prevents the sheet from becoming brittle due to excessive stress. Then, water quench the sheet to obtain Fe-Mn high-entropy alloy sheet. Water quenching is a rapid cooling process. During rapid water quenching, the diffusion ability of atoms decreases sharply, the phase transformation that would normally occur during slow cooling is suppressed, and the metastable structure at high temperature is preserved, significantly improving the strength-ductility product of the material.

[0026] The present invention also provides Fe-Mn high-entropy alloy sheet, which is prepared by the above-described method for preparing Fe-Mn high-entropy alloy sheet.

[0027] The microstructure of the high-entropy alloy was observed using electron backscatter diffraction (EBSD) analysis with a FEI Quanta 400FEG field emission electron microscope (SEM), and the mechanical properties were measured using an electronic universal testing machine (UTM5105). The Fe-Mn high-entropy alloy of this invention exhibits a higher strain rate and superior ultra-high strength-ductility product compared to other existing technologies. Compared to the technical bottleneck of traditional Fe-Mn high-entropy alloys where it is difficult to balance steel strength and ductility, this invention achieves a breakthrough improvement in mechanical properties through the synergistic control of composition design and preparation process, providing a new technical path for the industrial application of high-entropy alloys for high-performance structures.

[0028] Example 1: The preparation method of Fe-Mn high-entropy alloys includes the following steps: Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo, and FeC in an atomic ratio of Fe:Mn:Co:Cr:C:Mo of 48.5:29.1:9.7:9.7:2:1. The purity of Fe, Mn, Co, Cr, Mo, and FeC is 99.9%. Step 2: The raw materials Fe, Mn, Co, Cr, Mo, and FeC are loaded into the vacuum arc melting furnace. A mechanical pump is used to pre-evacuate the furnace to 7.5 Pa, then the shut-off valve is opened to evacuate to 5.5 Pa. Finally, a molecular pump is used to evacuate the furnace cavity to a vacuum of 2.5 × 10⁻⁶ Pa. -3 Argon gas is injected into the vacuum arc melting furnace until the internal pressure is -0.5 Pa and the argon concentration is 99.99 wt%. A titanium ingot with a purity of 99.95% is placed in one crucible in the vacuum arc melting furnace, and the remaining raw materials are placed in another crucible in the vacuum arc melting furnace. The titanium ingot is melted into a liquid state. The raw materials are continuously melted at a melting temperature of 1368℃ until they are completely melted into a liquid state. Button ingots are obtained in a mold. Each button ingot is turned over and melted five times, with each melting lasting 3 minutes. When the raw materials are cooled to room temperature, samples are taken to obtain high-entropy alloy ingots. During the melting process, the alloy melt is electromagnetically stirred, but electromagnetic stirring is not performed during the first and last melting. Step 3: Remelt the button ingot alloy and pour it into a plate mold to obtain a cast Fe-Mn high-entropy alloy.

[0029] During casting, the material cools rapidly due to its large contact area with the mold during solidification, resulting in a dense microstructure with fine grains and few defects in the as-cast plate. For example... Figure 1 As shown, the microstructure of the as-cast Fe-Mn high-entropy alloy in this embodiment is an FCC single-phase structure. Figure 2 The image shows a SEM image of the as-cast Fe-Mn high-entropy alloy. The grain size was determined using the scribing method. With increased cooling rate, the average grain size of the alloy was 45.599 μm. Figure 3 This is the room temperature uniaxial tensile curve of the as-cast Fe-Mn high-entropy alloy. In this embodiment, a uniform microstructure was obtained in the cast state. Since the microstructure plays a decisive role in mechanical properties, the cast state achieves an optimal combination of strength and ductility. The alloy has a total elongation (EL) of 93.1%, a tensile strength (UTS) of 712.289 MPa, and a calculated strength-ductility product (UTS×EL) of 66.31 GPa%. This strength-ductility product is far beyond what traditional steel alloys can achieve, and for other widely studied high-entropy alloys, a strength-ductility product of around 60 GPa% is relatively common.

[0030] Example 2: The preparation method of Fe-Mn high-entropy alloys includes the following steps: Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo, and FeC in an atomic ratio of Fe:Mn:Co:Cr:C:Mo of 45:28:9:9:2.05:0.8. The purity of Fe, Mn, Co, Cr, Mo, and FeC is 99.95%. Step 2: The raw materials Fe, Mn, Co, Cr, Mo, and FeC are loaded into a vacuum arc melting furnace. A mechanical pump is used to pre-evacuate the furnace to 8.5 Pa, then the shut-off valve is opened to evacuate to 6.5 Pa. Finally, a molecular pump is used to evacuate the furnace cavity to a vacuum of 3.5 × 10⁻⁶ Pa. -3 Argon gas is injected into the vacuum arc melting furnace until the internal pressure reaches -0.6 Pa and the argon concentration is 99.999 wt%. A titanium ingot with a purity of 99.97% is placed in one crucible inside the vacuum arc melting furnace, and the remaining raw materials are placed in another crucible inside the vacuum arc melting furnace. The titanium ingot is melted into a liquid state. The raw materials are continuously melted at a melting temperature of 1400℃ until they are completely melted into a liquid state. Button ingots are obtained in a mold. Each button ingot is turned over and melted six times, with each melting lasting 5 minutes. Samples are taken when the raw materials cool to room temperature to obtain high-entropy alloy ingots. The alloy melt is electromagnetically stirred during the melting process, except for the first and last melting. Step 3: Remelt the button ingot alloy and pour it into a plate mold to obtain a cast Fe-Mn high-entropy alloy.

[0031] Example 3: The preparation method of Fe-Mn high-entropy alloys includes the following steps: Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo, and FeC in an atomic ratio of Fe:Mn:Co:Cr:C:Mo of 50:29.5:10:10:2.1:1.2. The purity of Fe, Mn, Co, Cr, Mo, and FeC is 99.98%. Step 2: Load the raw materials Fe, Mn, Co, Cr, Mo, and FeC into the vacuum arc melting furnace. Pre-evacuate to 8 Pa using a mechanical pump, then open the shut-off valve to evacuate to 6 Pa. Finally, use a molecular pump to evacuate the furnace cavity to 3 × 10⁻⁶ Pa. -3Argon gas is injected into the vacuum arc melting furnace until the internal pressure is -0.8 Pa and the argon concentration is 99.995 wt%. A titanium ingot with a purity of 99.99% is placed in one crucible in the vacuum arc melting furnace, and the remaining raw materials are placed in another crucible in the vacuum arc melting furnace. The titanium ingot is melted into a liquid state. The raw materials are continuously melted at a melting temperature of 1450℃ until they are completely melted into a liquid state. Button ingots are obtained in a mold. Each button ingot is turned over and melted seven times, with each melting lasting 4 minutes. When the raw materials are cooled to room temperature, samples are taken to obtain high-entropy alloy ingots. During the melting process, the alloy melt is electromagnetically stirred, but electromagnetic stirring is not performed during the first and last melting. Step 3: Remelt the button ingot alloy and pour it into a plate mold to obtain a cast Fe-Mn high-entropy alloy.

[0032] Example 4: The preparation method of Fe-Mn high-entropy alloy plates includes the following steps: Step a: The Fe-Mn high-entropy alloy is hot-rolled at 950℃ for 30 passes using a rolling mill, with a total reduction of 25% and a strain of 4% per pass. The hot-rolled plate is then cooled at room temperature. Step b: Place the hot-rolled plate in a resistance box furnace and heat it to 1250℃ with the furnace, then hold it at that temperature for 2 hours; Step c: The solution-treated sheet is subjected to 40 cold rolling passes at room temperature, with a cold rolling deformation of 67% and a strain of 4% per pass; Step d: Anneal the cold-rolled sheet using 99.95% pure argon as a protective gas, heat it to 1000℃ in the furnace, hold it for 5 minutes, and then quench it in water to obtain Fe-Mn high-entropy alloy sheet.

[0033] like Figure 4 As shown, the final state high-entropy alloy microstructure after cold rolling and annealing in this embodiment is an FCC single-phase structure, as... Figure 5 As shown, in this embodiment, the Fe-Mn high-entropy alloy sheet undergoes grain elongation under 118% strain, resulting in the formation of numerous narrow, fine, and interacting deformed twins within the grains, thus increasing the number of twin boundaries. Twin boundaries are special low-energy interfaces, with an interface energy approximately 1 / 10 that of ordinary large-angle grain boundaries. Therefore, they effectively hinder dislocation movement. The interaction between twin boundaries and dislocations both contribute to increased alloy strength, and within a certain range, the thinner the twin sheet layer, the greater the hardness. However, research indicates that when the twin sheet layer is very thin, the strength decreases, leading to softening. The contribution of deformed twins to plasticity is mainly due to three factors: low twin boundary energy, dislocation absorption by the twins, and dislocation slippage at the twin boundaries. In the figure, the thin thickness of the deformed twin sheet layer effectively promotes increased plasticity and toughness. Figure 6The figure shows the room temperature tensile curve of the final alloy sheet. When the purpose of annealing is to restore and recrystallize the microstructure, increasing the annealing temperature and shortening the annealing time are key to obtaining a fine and dense microstructure. In this embodiment, a uniform microstructure was obtained by treating at 1000℃ for 5 minutes. Compared with the mechanical properties of the cast state, this treatment process yielded an excellent combination of strength and ductility. Although the yield strength decreased, the total elongation (EL) of the alloy reached 118.1%, and the tensile strength (UTS) remained at 807.551 MPa due to the high elongation. The calculated strength-ductility product (UTS×EL) reached 95.37 GPa, while the strength-ductility product in the cast state was only 66.31 GPa.

[0034] Example 5: The preparation method of Fe-Mn high-entropy alloy plates includes the following steps: Step a: The Fe-Mn high-entropy alloy is hot-rolled at 900°C using a rolling mill for 40 passes, with a total reduction of 30% and a strain of 3% per pass. The hot-rolled plate is then cooled to room temperature. Step b: Place the hot-rolled plate in a resistance box furnace and heat it to 1180℃ with the furnace, then hold it at that temperature for 2 hours; Step c: The solution-treated sheet is subjected to 50 cold rolling passes at room temperature, with a cold rolling deformation of 60% and a strain of 3% per pass; Step d: Anneal the cold-rolled sheet using 99.98% pure argon as a protective gas, heat it to 1050℃ in the furnace, hold it for 3 minutes, and then quench it in water to obtain Fe-Mn high-entropy alloy sheet.

[0035] Example 6: The preparation method of Fe-Mn high-entropy alloy plates includes the following steps: Step a: The Fe-Mn high-entropy alloy is hot-rolled at 925℃ using a rolling mill for 35 passes, with a total reduction of 27% and a strain of 3.5% per pass. The hot-rolled plate is then cooled at room temperature. Step b: Place the hot-rolled plate in a resistance box furnace and heat it to 1220℃ with the furnace, then hold it at that temperature for 1.5 hours. Step c: The solution-treated sheet is subjected to 45 cold rolling passes at room temperature, with a cold rolling deformation of 70% and a strain of 3.5% per pass; Step d: Anneal the cold-rolled sheet using 99.97% pure argon as a protective gas, heat it to 1025℃ in the furnace, hold it for 4 minutes, and then quench it in water to obtain Fe-Mn high-entropy alloy sheet.

Claims

1. A method for preparing Fe-Mn high-entropy alloys, characterized in that, Includes the following steps: Step 1: Mix the raw materials Fe, Mn, Co, Cr, Mo and FeC according to the atomic ratio Fe:Mn:Co:Cr:C:Mo of 45~50:28~29.5:9~10:9~10:2~2.1:0.8~1.2; Step 2: Put the above raw materials into a vacuum electric arc melting furnace and carry out electric arc melting in an inert gas atmosphere to obtain button ingots; Step 3: Remelt the button ingot alloy and pour it into a plate mold to obtain a cast Fe-Mn high-entropy alloy.

2. The method for preparing Fe-Mn high-entropy alloys according to claim 1, characterized in that, In step 1, the purity of the raw materials Fe, Mn, Co, Cr, Mo and FeC is not less than 99.9%.

3. The method for preparing Fe-Mn high-entropy alloys according to claim 1, characterized in that, Step 2 is performed as follows: Step 2.1: Load the raw materials Fe, Mn, Co, Cr, Mo, and FeC into a vacuum arc melting furnace, and evacuate the furnace cavity to a vacuum level of 2.5 × 10⁻⁶. -3 Pa ~ 3.5 × 10 -3 Pa; Step 2.2: Inject argon gas into the vacuum arc melting furnace until its internal pressure is not higher than -0.5 Pa and the argon gas concentration is not lower than 99.99 wt%. Step 2.3: Place titanium ingots with a purity of not less than 99.95% in one crucible in a vacuum arc melting furnace, and place the remaining raw materials in another crucible in the vacuum arc melting furnace to melt the titanium ingots into a liquid state. Step 2.4: continuously melt the raw materials at a temperature of not less than 1368℃ until they are completely melted into a liquid state and then obtain button ingots in the mold. Each button ingot is turned over and melted at least five times, with each melting lasting 3 to 5 minutes. Take a sample when the raw materials have cooled to room temperature. Electromagnetically stir the alloy melt during the melting process, but do not perform electromagnetic stirring during the first and last melting.

4. A Fe-Mn based high-entropy alloy, characterized in that, The Fe-Mn high-entropy alloy is prepared by the preparation method of the Fe-Mn high-entropy alloy according to any one of claims 1-3.

5. A method for preparing Fe-Mn based high-entropy alloy plates, characterized in that, Includes the following steps: Step a: Hot-roll the Fe-Mn high-entropy alloy and cool it at room temperature to obtain a hot-rolled plate; Step b: Perform solution treatment on the hot-rolled plate; Step c: The solution-treated sheet is cold-rolled to obtain a cold-rolled sheet; Step d: The cold-rolled sheet is annealed and water-quenched in sequence to obtain Fe-Mn high-entropy alloy sheet.

6. The method for preparing Fe-Mn high-entropy alloy plate according to claim 5, characterized in that, Step a specifically involves: hot-rolling the Fe-Mn high-entropy alloy at 900~950℃ using a rolling mill for no less than 30 passes, with a total reduction of 25%~30% and a strain of no more than 4% per pass, followed by cooling at room temperature to obtain a hot-rolled plate.

7. The method for preparing Fe-Mn high-entropy alloy plate according to claim 5, characterized in that, Step b specifically involves placing the hot-rolled plate in a resistance box furnace and heating it to 1180℃~1250℃, then holding it at that temperature for 1h~2h.

8. The method for preparing Fe-Mn high-entropy alloy plate according to claim 5, characterized in that, Step c specifically involves: subjecting the solution-treated sheet to cold rolling at room temperature for no less than 40 passes, with a cold rolling deformation of 60% to 70% and a strain of no more than 4% per pass.

9. The method for preparing Fe-Mn high-entropy alloy plate according to claim 5, characterized in that, The annealing process is as follows: using argon gas with a purity of not less than 99.95% as a protective gas, the furnace is heated to 1000℃~1050℃ and held for 3min~5min.

10. Fe-Mn series high-entropy alloy plate, characterized in that, The Fe-Mn high-entropy alloy plate is prepared by the preparation method of the Fe-Mn high-entropy alloy plate according to any one of claims 5-8.

Images