A nano-precipitation strengthening high-entropy alloy with stable phase structure in a wide temperature range and a preparation method thereof

Abstract

This invention discloses a nano-precipitation-strengthened high-entropy alloy with a stable phase structure over a wide temperature range, belonging to the field of materials processing. The alloy's composition is Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2‑x Ta x B 0.1 The high-entropy alloy prepared by this invention exhibits characteristics such as stable high-temperature phase structure and high volume content of reinforcing phase. Furthermore, this type of alloy not only possesses high yield strength but also good plastic deformation and significant work hardening properties. (2≥x≥0)

Description

Technical Field

[0001] This invention relates to a novel material alloy and its preparation method, specifically to a high-strength, high-toughness, wide-temperature-range stable phase structure nano-precipitation strengthened high-entropy alloy and its preparation method, belonging to the field of materials processing. Background Technology

[0002] High-temperature materials are widely used in the aerospace field, such as turbine disks, blades, rings, elastic elements, and sealing elements for aircraft engines; rocket nozzles and turbine rotors; and high-temperature components such as the leading edges of supersonic aircraft. Currently, the most widely used high-temperature metallic materials include cobalt-based superalloys, iron-based superalloys, and nickel-based superalloys. Traditional Inconel 718 nickel-based forged superalloys are widely used in heat-bearing components such as turbine disks due to their excellent fatigue resistance, radiation resistance, oxidation resistance, corrosion resistance, and good machinability and weldability; however, their operating temperature range is often below 650°C. By adding nearly 10% Co, In718Plus alloy was prepared, a new type of nickel-based superalloy, increasing its operating temperature to 700°C. In718Plus has become a new generation of wrought superalloy turbine disk material. To further improve its service range, Udimet 720Li added a higher content of ~15 at.% Co to increase its operating temperature range, thus covering a service range between 650°C and 800°C. Therefore, increasing the Co content can improve its heat resistance and stabilize the phase structure. A higher Co content helps to accommodate complex elements while maintaining a stable phase structure. This is because Co has a higher melting point and can equivalently replace Ni.

[0003] In order to provide high-temperature turbine disk components that can withstand higher service temperatures, it is urgent to develop a new type of high-entropy alloy for high-temperature applications with nanoprecipitation strengthening. This type of high-temperature alloy must have the characteristics of stable phase structure and high strength and toughness over a wide temperature range. Summary of the Invention

[0004] To address the problems of phase structure instability and low volumetric content of strengthening phases in traditional high-temperature alloys during long-term service at temperatures of 800 °C and above, this invention provides a high-strength, high-toughness, wide-temperature-range stable phase structure nano-precipitation strengthened high-entropy alloy and its preparation method, thereby obtaining a high-strength, high-toughness high-entropy alloy. This invention also provides a multi-principal-element nano-precipitation strengthened alloy and its preparation method.

[0005] This invention, through phase diagram calculations combined with experiments, designs a nano-precipitation-reinforced high-strength, high-toughness, high-entropy alloy with a stable phase structure over a wide temperature range. The alloy designed in this invention exhibits high strength and toughness, and in a temperature range above 710 °C, only the FCC and L12 phases exist, demonstrating a stable phase structure. Even after prolonged treatment at 800 °C, it retains over 50% of the reinforcing phase volume content, which is better than other nano-precipitation high-entropy alloys and most traditional high-temperature alloys, making it highly suitable for high-temperature applications. Furthermore, by optimizing the heat treatment process and employing a two-step aging treatment, a bimodal nano-precipitation-reinforced high-entropy alloy with higher yield strength can be prepared.

[0006] This invention provides a high-strength, high-toughness, wide-temperature-range phase-structure-stable nanoprecipitation-strengthened high-entropy alloy, the composition of which is Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 , 2 ≥ x ≥ 0, the microstructure is an equiaxed crystal structure with nano-precipitated strengthening phases, and the nano-precipitated particles are coherent with the matrix.

[0007] Furthermore, the mass fraction of Ni, Co, Fe, Cr, Al, Ti, Nb, Ta and B used in the alloy smelting process is not less than 99.9%.

[0008] This invention provides a method for preparing the above-mentioned wide-temperature-range phase-structure-stable nano-precipitation-strengthened high-entropy alloy, comprising the following steps: preparing a multi-principal-element alloy ingot using Ni, Co, Fe, Cr, Al, Ti, Nb, Ta, and B smelting raw materials; subjecting the multi-principal-element alloy ingot to homogenization heat treatment at 1150-1200 ℃, followed by cold rolling with a total deformation of 60-65%, partial recrystallization heat treatment at 1200 ℃ for 0.5-2 min, and then aging heat treatment at 800 ℃ for 12-24 h to obtain the above-mentioned alloy.

[0009] The above preparation method specifically includes the following steps:

[0010] Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix raw material particles of Ni, Co, Fe, Cr, Al, Nb, Ti, Ta, and B with a purity ≥99.9 wt.% according to a molar ratio of 42.9∶20∶10∶13∶9∶3∶2-x∶x∶0.1 to obtain a nominal composition of Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2-x Ta x B 0.1 Alloy mixture particles with 2 ≥ x ≥ 0;

[0011] Place the weighed raw material particles into a beaker, ultrasonically clean for 5 minutes, and then dry with a hair dryer.

[0012] Step 2: Melting: Using a WK-II type non-consumable vacuum arc furnace under argon protection, the weighed and proportioned Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 The alloy mixed particles are first melted into alloy ingots, and the melting-turning-melting process is repeated more than 5 times to ensure that the alloy elements are evenly distributed.

[0013] Step 3: Casting: The uniformly molten alloy ingot is placed on a water-cooled crucible with a casting mold by a robotic arm. Circulating water is provided under the crucible. Then, the uniformly molten alloy is heated to a molten state. The molten metal is poured into a 5×10×40mm water-cooled copper mold. After the sample cools down, the sample is taken out.

[0014] Step 4: Thermomechanical treatment: The smelted sample is subjected to homogenization heat treatment at 1150-1200 ℃ for 2h, followed by cold rolling with a reduction of 60-65%. After cold rolling, the sample is recrystallized at 1200 ℃ for 0.5-2min, followed by aging treatment at 800 ℃ for 12-24h to prepare an alloy with high strength and stable phase structure over a wide temperature range.

[0015] As a preferred embodiment, the above-mentioned method for preparing high-entropy alloys is further optimized as follows: Following steps 1 to 3 above, Ni is first prepared. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1The high-entropy alloy ingots with 2 ≥ x ≥ 0 were cast and then subjected to thermomechanical treatment. The specific process of thermomechanical treatment was as follows: the smelted samples were subjected to homogenization heat treatment at 1150-1200 ℃ for 2h, followed by cold rolling with a reduction of 60-65%. After cold rolling, the samples were recrystallized at 1200 ℃ for 0.5~2min to obtain recrystallized samples with different grain sizes. Then, they were cold rolled with a reduction of 50%. After cold rolling, the samples were recrystallized at 1080 ℃ for 2min, followed by aging treatment at 800 ℃ for 12-24h to prepare nano-precipitation strengthened high-entropy alloys with higher strength (yield strength of 1200-1500 MPa).

[0016] The beneficial effects of this invention are:

[0017] (1) The Ni prepared by this invention 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 ,2 ≥ x ≥ 0 nanometer precipitated high entropy alloy, with high volume content of high temperature strengthening phase, stable phase structure, strong toughness and other characteristics. It is a single FCC+L12 phase structure with uniform microstructure. It not only has high yield strength (>1134.5 MPa), but also good plastic deformation (>20%) and significant work hardening performance.

[0018] (2) By optimizing the thermomechanical treatment process, a two-step aging method is used to obtain Ni with a bimodal structure. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 Nano-precipitated high-entropy alloys have the characteristics of higher strength, stable phase structure, and high toughness. Attached Figure Description

[0019] Figure 1 Ni prepared in Example 1 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 XRD patterns and phase diagrams;

[0020] Figure 2 Ni prepared in Example 1 42.9 Co 20 Fe 10 Cr 13Al9Nb3Ti2B 0.1 EBSD histogram;

[0021] Figure 3 Ni prepared in Example 1 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 The engineering stress-strain curve diagram;

[0022] Figure 4 Ni is prepared in Example 2 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti1Ta1B 0.1 XRD patterns and EBSD histograms;

[0023] Figure 5 Ni is prepared in Example 2 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti1Ta1B 0.1 The engineering stress-strain curve diagram;

[0024] Figure 6 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 XRD patterns and phase diagrams;

[0025] Figure 7 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 EBSD histogram;

[0026] Figure 8 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The engineering stress-strain curve diagram;

[0027] Figure 9 Ni is prepared in Example 4 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B0.1 EBSD diffraction band contrast diagrams of nano-precipitated high-entropy alloy after rolling and recrystallization treatment at 1200 °C for (a) 30 s and (b) 2 min, followed by subsequent cold rolling and two-step aging treatment.

[0028] Figure 10 Ni is prepared in Example 4 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The nano-precipitated high-entropy alloy was rolled and then annealed at 1200 °C for (a) 30 s and (b) 2 min, respectively. After subsequent cold rolling and two-step aging treatment, the strain rate at room temperature was 1×10⁻⁶. -3 The stress-strain curve of tensile engineering per second. Detailed Implementation

[0029] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Example 1

[0031] This embodiment provides an ultra-high strength and toughness nanoprecipitation-reinforced high-entropy alloy composition with a stable phase structure over a wide temperature range. The alloy composition consists of Ni, Co, Fe, Cr, Al, Nb, Ti, and B, with the following molar ratios: Ni, Co, Fe, Cr, Al, Nb, Ti, and B are 42.9, 20, 10, 13, 9, 3, 2, and 0.1, respectively. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 .

[0032] The preparation steps of the above-mentioned high-entropy alloy are as follows:

[0033] Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix the raw material particles with a purity ≥99.95% Ni, Co, Fe, Cr, Al, Nb, Ti, and B according to a molar ratio of 42.9, 20, 10, 13, 9, 3, 2, 0.1. (The last part, "Ni," appears to be an unrelated instruction and is left untranslated.) 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1Place the raw material into a beaker containing anhydrous ethanol and ultrasonically clean it for about 5 minutes to remove surface impurities and dirt, then dry it with a hair dryer.

[0034] Step 2: Melting: Under an argon atmosphere, the weighed and proportioned elements are first melted into alloy ingots. Melting-turning-melting is repeated more than 5 times to ensure that the alloy elements are evenly distributed.

[0035] Step 3: Casting: Heat the homogeneous alloy to a molten state and cast it to a size of 5×10×40mm. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down.

[0036] Step 4: Heat Treatment: The smelted sample was subjected to homogenization heat treatment at 1200 ℃ for 2 h, followed by cold rolling with a 60% reduction. After cold rolling, the sample was recrystallized at 1200 ℃ for 2 min, and then aged at 800 ℃ for 12 h. Ni was obtained. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 Nanoprecipitation reinforced alloy.

[0037] Figure 1 a and b are Ni prepared in Example 1, respectively. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 The XRD pattern and phase diagram show that the alloy has an FCC+L12 structure. Figure 2 Ni prepared in Example 1 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 The EBSD microstructure diagram shows that the alloy has an equiaxed crystal structure. Figure 3 The Ni prepared in Example 1 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti2B 0.1 The engineering stress-strain curve is shown. The alloy has a yield strength of 1050 MPa and high room temperature ductility of 23.1%. Example 2

[0038] This embodiment provides an ultra-high strength and toughness nanoprecipitation-reinforced high-entropy alloy composition with a stable phase structure over a wide temperature range. The alloy composition consists of Ni, Co, Fe, Cr, Al, Nb, Ta, Ti, and B, with the following molar ratios: Ni, Co, Fe, Cr, Al, Nb, Ta, Ti, and B are 42.9, 20, 10, 13, 9, 3, 1, 1, 0.1, i.e., Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta1Ti1B 0.1 .

[0039] The preparation steps of the above-mentioned high-entropy alloy are as follows:

[0040] Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix the raw material particles with a purity ≥99.95% Ni, Co, Fe, Cr, Al, Nb, Ta, Ti, and B according to a molar ratio of 42.9, 20, 10, 13, 9, 3, 1, 1, 0.1. (The last part, "Ni," appears to be an unrelated instruction and is left untranslated.) 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta1Ti1B 0.1 Place the raw material into a beaker containing anhydrous ethanol and ultrasonically clean it for about 5 minutes to remove surface impurities and dirt, then dry it with a hair dryer.

[0041] Step 2: Melting: Under an argon atmosphere, the weighed and proportioned elements are first melted into alloy ingots. Melting-turning-melting is repeated more than 5 times to ensure that the alloy elements are evenly distributed.

[0042] Step 3: Casting: Heat the homogeneous alloy to a molten state and cast it to a size of 5×10×40mm. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down.

[0043] Step 4: Heat Treatment: The smelted sample was subjected to homogenization heat treatment at 1200 ℃ for 2 h, followed by cold rolling with a 60% reduction. After cold rolling, the sample was recrystallized at 1200 ℃ for 2 min, and then aged at 800 ℃ for 12 h. Ni was obtained. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta1Ti1B 0.1 Nanoprecipitation reinforced alloy.

[0044] Figure 4 The Ni prepared in Example 2 42.9 Co 20Fe 10 Cr 13 Al9Nb3Ta1Ti1B 0.1 The XRD pattern and EBSD microstructure of the alloy show that it has an FCC+L12 structure. Figure 5 Ni is prepared in Example 2 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta1Ti1B 0.1 Stress-strain curves for engineering applications. This alloy has a yield strength of 1080 MPa and high room temperature ductility of 25.3%. Example 3

[0045] This embodiment provides a nano-precipitation-reinforced high-entropy alloy composition with ultra-high room temperature strength and toughness. The alloy composition consists of Ni, Co, Fe, Cr, Al, Nb, Ta, and B, with the following molar ratios: Ni, Co, Fe, Cr, Al, Nb, Ta, and B are 42.9, 20, 10, 13, 9, 3, 2, 0.1, i.e., Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 .

[0046] The preparation steps of the above-mentioned high-entropy alloy are as follows:

[0047] Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix the raw material particles with a purity ≥99.95% Ni, Co, Fe, Cr, Al, Nb, Ta, and B according to a molar ratio of 42.9, 20, 10, 13, 9, 3, 2, 0.1. (The remaining text appears to be incomplete and requires further context.) 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 Place the raw material into a beaker containing anhydrous ethanol and ultrasonically clean it for about 5 minutes to remove surface impurities and dirt, then dry it with a hair dryer.

[0048] Step 2: Melting: Under an argon atmosphere, the weighed and proportioned elements are first melted into alloy ingots. Melting-turning-melting is repeated more than 5 times to ensure that the alloy elements are evenly distributed.

[0049] Step 3: Casting: Heat the homogeneous alloy to a molten state and cast it to a size of 5×10×40mm. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down.

[0050] Step 4: Heat Treatment: The smelted sample was subjected to homogenization heat treatment at 1200 ℃ for 2 h, followed by cold rolling with a 60% reduction. After cold rolling, the sample was recrystallized at 1200 ℃ for 2 min, and then aged at 800 ℃. Ni was obtained. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 Nanoprecipitation reinforced alloy.

[0051] Figure 6 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The XRD pattern and phase diagram show that the alloy has an FCC+L12 two-phase structure. Figure 7 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The EBSD microstructure diagram shows that the alloy has an equiaxed crystal structure. Figure 8 Ni is prepared in Example 3 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The engineering stress-strain curve is shown. The alloy has a yield strength of 1143 MPa and maintains extremely high room temperature ductility of 23.8%. Example 4

[0052] This embodiment provides a nano-precipitated high-entropy alloy composition with ultra-high room temperature tensile strength and plasticity exhibiting a heterogeneous structure. The alloy composition consists of Ni, Co, Fe, Cr, Al, Nb, Ta, and B, with the following molar ratios: Ni, Co, Fe, Cr, Al, Nb, Ta, and B are 42.9, 20, 10, 13, 9, 3, 2, 0.1, i.e., Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 .

[0053] The preparation steps of the above-mentioned high-entropy alloy are as follows:

[0054] Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix the raw material particles with a purity ≥99.95% Ni, Co, Fe, Cr, Al, Nb, Ta, and B according to a molar ratio of 42.9, 20, 10, 13, 9, 3, 2, 0.1. (The remaining text appears to be incomplete and requires further context.) 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 Place the raw material into a beaker containing anhydrous ethanol and ultrasonically clean it for about 5 minutes to remove surface impurities and dirt, then dry it with a hair dryer.

[0055] Step 2: Melting: Under an argon atmosphere, the weighed and proportioned elements are first melted into alloy ingots. Melting-turning-melting is repeated more than 5 times to ensure that the alloy elements are evenly distributed.

[0056] Step 3: Casting: Heat the homogeneous alloy to a molten state and cast it to a size of 5×10×40mm. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down.

[0057] Step 4: Heat Treatment: The smelted sample is subjected to homogenization heat treatment at 1200 ℃ for 2 hours, followed by cold rolling with a 60% reduction. The cold-rolled Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 A two-step aging heat treatment was performed to obtain a nano-precipitated high-entropy alloy with finer grain size. Specifically, after cold rolling, the samples were recrystallized at 1200 °C for 30 s and 2 min respectively to obtain recrystallized samples with different grain sizes. Subsequently, the samples were cold rolled with a 50% reduction, and then recrystallized at 1080 °C for 2 min, followed by aging at 800 °C for 12 h. This process yielded a high-entropy alloy with a heterogeneous nano-precipitated structure and higher strength.

[0058] Figure 9 Ni is prepared in Example 4 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The EBSD diffraction band contrast diagrams of the nano-precipitated high-entropy alloy after rolling were subjected to recrystallization treatment at 1200 °C for (a) 30 s and (b) 2 min, respectively, followed by rolling of 50%, and then annealing at 1080 °C for 2 min and aging at 800 °C for 12 h. The diagrams show that the alloy has a heterogeneous structure and also has some equiaxed crystal morphology.

[0059] Figure 10 Example 4 shows the preparation of heterostructured Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ta2B 0.1 The high-entropy alloy was rolled and then annealed at 1200 °C for (a) 30 s and (b) 2 min, and then subjected to cold rolling and two-step aging treatment at room temperature with a strain rate of 1 × 10⁻⁶. -3 The tensile stress-strain curve of the heterostructured nano-precipitated high-entropy alloy is shown in the figure. It can be seen from the figure that the yield strength of the rolled heterostructured nano-precipitated high-entropy alloy is 1480 and 1288 MPa, and the plasticity reaches over 10%.

Claims

1. A nano-precipitation-strengthened high-entropy alloy with a wide-temperature-range phase structure stability, characterized in that: The composition of the alloy is Ni 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 , 2 ≥ x ≥ 0, the molar ratio of each element Ni, Co, Fe, Cr, Al, Nb, Ti, Ta and B is 42.9:20:10:13:9:3:2-x:x:0.1, the microstructure of the alloy is equiaxed crystal structure with nano-precipitation strengthening phase, and the nano-precipitation particles and the matrix maintain a coherent relationship; The preparation method of the wide-temperature-range phase-structure stable nano-precipitation strengthened high-entropy alloy includes the following steps: preparing a multi-principal-element alloy ingot using Ni, Co, Fe, Cr, Al, Ti, Nb, Ta and B smelting raw materials; subjecting the multi-principal-element alloy ingot to homogenization heat treatment at 1150-1200 ℃, followed by cold rolling with a total deformation of 60-65%, partial recrystallization heat treatment at 1200 ℃ for 0.5-2 min, and then aging heat treatment at 800 ℃ for 12-24 h to obtain the above alloy.

2. The nano-precipitation-strengthened high-entropy alloy with a stable phase structure over a wide temperature range according to claim 1, characterized in that... Specifically, the following steps are included: Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix raw material particles of Ni, Co, Fe, Cr, Al, Nb, Ti, Ta, and B with a purity ≥99.9 wt.% according to a molar ratio of 42.9∶20∶10∶13∶9∶3∶2-x∶x∶0.1 to obtain a nominal composition of Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 Alloy mixture particles with 2 ≥ x ≥ 0; Place the weighed raw material particles into a beaker, ultrasonically clean for 5 minutes, and then dry with a hair dryer. Step 2: Melting: Using a WK-II type non-consumable vacuum arc furnace under argon protection, the weighed and proportioned Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 The alloy mixed particles are first melted into alloy ingots, and the melting-turning-melting process is repeated more than 5 times to ensure that the alloy elements are evenly distributed. Step 3: Casting: The homogeneously molten alloy ingot is placed on a water-cooled crucible with a casting mold using a robotic arm. Circulating water is installed beneath the crucible. The homogeneously molten alloy is then heated to a molten state, and the molten metal is poured into a 5×10×40mm ingot. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down. Step 4: Thermomechanical treatment: The smelted sample is subjected to homogenization heat treatment at 1150-1200 ℃ for 2h, followed by cold rolling with a reduction of 60-65%. After cold rolling, the sample is recrystallized at 1200 ℃ for 0.5-2min, followed by aging treatment at 800 ℃ for 12-24h to prepare an alloy with high strength and stable phase structure over a wide temperature range.

3. A nano-precipitation-strengthened high-entropy alloy with a wide-temperature-range phase structure stability, characterized in that: The alloy's composition is Ni 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 , 2 ≥ x ≥ 0, the molar ratio of each element Ni, Co, Fe, Cr, Al, Nb, Ti, Ta and B is 42.9∶20∶10∶13∶9∶3∶2-x∶x∶0.1, the alloy microstructure is an equiaxed crystal structure with nano-precipitated strengthening phases, and the nano-precipitated particles maintain a coherent relationship with the matrix; The preparation method of the nano-precipitation strengthened high-entropy alloy includes the following steps: Step 1: Weighing: Using an electronic balance with an accuracy of 0.0001g, weigh and mix raw material particles of Ni, Co, Fe, Cr, Al, Nb, Ti, Ta, and B with a purity ≥99.9 wt.% according to a molar ratio of 42.9∶20∶10∶13∶9∶3∶2-x∶x∶0.1 to obtain a nominal composition of Ni. 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 Alloy mixture particles with 2 ≥ x ≥ 0; Place the weighed raw material particles into a beaker, ultrasonically clean for 5 minutes, and then dry with a hair dryer. Step 2: Melting: Using a WK-II type non-consumable vacuum arc furnace under argon protection, the weighed and proportioned Ni... 42.9 Co 20 Fe 10 Cr 13 Al9Nb3Ti 2-x Ta x B 0.1 The alloy mixed particles are first melted into alloy ingots, and the melting-turning-melting process is repeated more than 5 times to ensure that the alloy elements are evenly distributed. Step 3: Casting: The homogeneously molten alloy ingot is placed on a water-cooled crucible with a casting mold using a robotic arm. Circulating water is installed beneath the crucible. The homogeneously molten alloy is then heated to a molten state, and the molten metal is poured into a 5×10×40mm ingot. 3 The sample was placed in a water-cooled copper mold and removed after it cooled down. Step 4: Thermomechanical treatment: The specific process of thermomechanical treatment is as follows: the smelted sample is subjected to homogenization heat treatment at 1150-1200 ℃ for 2h, followed by cold rolling with a reduction of 60-65%. After cold rolling, the sample is subjected to recrystallization treatment at 1200 ℃ for 0.5~2min to obtain recrystallized samples with different grain sizes. Then, it is subjected to cold rolling with a reduction of 50%. After cold rolling, the sample is treated at 1080 ℃ for 2min, followed by aging treatment at 800 ℃ for 12h~24h to prepare the nano-precipitation strengthened high-entropy alloy.

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