Refractory medium-entropy alloy material with low thermal neutron absorption cross section and preparation method of refractory medium-entropy alloy material

Abstract

The invention discloses a refractory medium-entropy alloy material with a low thermal neutron absorption cross section and a preparation method of the refractory medium-entropy alloy material, and belongs to the technical field of medium-entropy alloys, the expression general formula of the refractory medium-entropy alloy material is YaZrbNbcMod, and a, b, c and d respectively represent the atomic percentage content of each corresponding element and meet the following conditions: 0 < = a < = 30, 15 < = b < = 55, 15 < = c < = 45, 10 < = d < = 40, and a + b + c + d = 100; the refractory medium-entropy alloy material is obtained in a vacuum arc melting mode, has a high theoretical melting point, high room-temperature yield strength and a low low-thermal neutron absorption cross section, can be used in the key technical field of nuclear power and the like, is particularly used as a core cladding material, and has high safety and reliability.

Description

Technical Field

[0001] This invention relates to a refractory medium-entropy alloy material with a low thermal neutron absorption cross section and its preparation method, belonging to the field of medium-entropy alloy technology. Background Technology

[0002] Since the 1970s, nuclear power has proven to be a reliable, environmentally sustainable, clean, and cost-effective energy source. Zirconium alloys such as Zr-2 and Zr-4, due to their low thermal neutron absorption cross section, excellent corrosion resistance under normal operating conditions, good mechanical properties, and good performance, have been widely used as fuel cladding materials for light water reactors. Newly developed zirconium alloys (such as E635, Zirlo, and M5) have significantly improved corrosion resistance and mechanical properties and have been applied to nuclear reactors to achieve higher coolant temperatures, higher fuel combustion rates, higher fuel utilization rates, and longer fuel cycles. However, in coolant loss accidents, zirconium alloys experience severe strength loss and rapid oxidation by high-temperature steam at temperatures above 1200°C. To achieve higher safety margins in accident scenarios, the concept of Accident Tolerant Fuel (ATF) has been proposed. Considering the limitations of traditional alloys, attempts are being made to apply emerging materials to the design of cladding materials for this fuel system.

[0003] Recently, a class of materials known as medium / high entropy alloys has attracted increasing attention from academia and industry due to their unique microstructure and superior mechanical properties. The emergence of medium / high entropy alloys breaks the constraints of traditional alloy design concepts composed of one or two main elements, expanding the development space of alloy materials. According to relevant research reports, medium / high entropy alloys possess many advantages, such as high strength, radiation resistance, good ductility, softening resistance, corrosion resistance, and oxidation resistance, indicating their potential for nuclear applications. Considering reactor safety and neutron effectiveness, cladding materials should possess high strength and a low thermal neutron absorption cross section. This invention aims to achieve a low thermal neutron absorption cross section (σ... A Using elements Y (1.28), Zr (0.185), Nb (1.15), and Mo (2.48) as raw materials, the developed Y-Zr-Nb-Mo medium-entropy alloy material has high strength. In addition, due to the high melting points of Y, Zr, Nb, and Mo, the alloy also has a high theoretical melting point, which effectively improves the failure problem of existing ATF-clad Zr alloy materials. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, the primary objective of this invention is to provide a refractory medium-entropy alloy material with a low thermal neutron absorption cross section, composed of elements Y, Zr, Nb, and Mo. This refractory medium-entropy alloy material with a low thermal neutron absorption cross section possesses high yield strength, a high theoretical melting point, and a low thermal neutron absorption cross section, making it suitable for use in key technology fields such as nuclear power, particularly as a nuclear cladding material, exhibiting high safety and reliability. The general expression for this refractory medium-entropy alloy material is Y... a Zr b Nb c Mo d , where a, b, c, d represent the atomic percentage content of each corresponding element, and satisfy the following conditions: 0≤a≤30, 15≤b≤55, 15≤c≤45, 10≤d≤40, a+b+c+d=100.

[0005] Another object of the present invention is to provide a method for preparing the refractory medium-entropy alloy material with the low thermal neutron absorption cross section, the specific steps of which are as follows: (1) After grinding and acid washing, Y, Zr, Nb and Mo raw materials are cleaned and dehydrated.

[0006] (2) The raw material that has been dehydrated is vacuum deoxidized, then melted, cooled and solidified to obtain an ingot, the ingot is flipped and melted again, and cooled to room temperature to obtain a refractory medium entropy alloy with low thermal neutron absorption cross section.

[0007] Preferably, in step (1) of the present invention, the pickling process involves soaking in a hydrochloric acid aqueous solution with a mass percentage concentration of 5-10% for 5-10 minutes, followed by rinsing with water and dehydration with an organic solvent.

[0008] As a further preferred embodiment of the present invention, the organic solvent is anhydrous ethanol.

[0009] Preferably, the vacuum deoxidation conditions in step (2) of the present invention are: 1000-1200℃, vacuum degree ≤5×10 - 2 Keep warm for 2-4 hours under the condition of Pa.

[0010] Preferably, in step (2) of the present invention, the raw materials are placed in order of increasing melting point to ensure that the low melting point element is located at the bottom of the smelting device.

[0011] Preferably, during the melting process in step (2) of the present invention, a vacuum must be drawn first, with a vacuum degree ≤ 5 × 10⁻⁶. -3 Pa, high-purity argon gas (99.9 wt.%) is introduced to maintain a protective atmosphere, and the argon gas pressure inside the melting device is lower than the ambient gas pressure outside the device.

[0012] Preferably, in step (2) of the present invention, during smelting, magnetic stirring technology is used to mix the metal solution evenly, and the ingot is turned over 5-8 times.

[0013] The beneficial effects of this invention are: (1) This invention utilizes a low thermal neutron absorption cross section (σ A Using elements Y (1.28), Zr (0.185), Nb (1.15), and Mo (2.48) as raw materials, the prepared Y-Zr-Nb-Mo refractory medium-entropy alloy material has a low thermal neutron absorption cross section, which is located between 0.75 and 1.58 barn. The low neutron effect can effectively reduce neutron capture and reduce neutron decay loss.

[0014] (2) The present invention utilizes elements with high melting points, Y (1522℃), Zr (1855℃), Nb (2477℃) and Mo (2623℃), as raw materials to prepare a Y-Zr-Nb-Mo refractory medium-entropy alloy material with a high theoretical melting point. The theoretical melting point of the alloy is calculated to be between 1,925-2,442℃ using the mixing rule. The high melting point makes the material have a low heat limit and high safety.

[0015] (3) The Y-Zr-Nb-Mo refractory medium-entropy alloy material prepared by the present invention has good mechanical properties, of which the compressive yield strength of the optimal alloy is 1,910 MPa, the compressive strength is 2,762 MPa, and the fracture strain is 22.4%.

[0016] (4) The Y-Zr-Nb-Mo refractory medium-entropy alloy material prepared by the present invention does not require complex processing technology such as heat treatment and machining. The preparation process is simple and highly controllable, and it is easy to realize large-scale industrial production.

[0017] (5) The Y-Zr-Nb-Mo refractory medium-entropy alloy material prepared by the present invention has a high theoretical melting point, high room temperature yield strength and low thermal neutron absorption cross section, and has high safety and reliability, thus having good application prospects in the nuclear power industry. Attached Figure Description

[0018] Figure 1 This is the room temperature compression engineering stress-strain curve of the refractory medium-entropy alloy material with low thermal neutron absorption cross section prepared according to the embodiments of the present invention.

[0019] Figure 2 This is the X-ray diffraction pattern of the refractory medium-entropy alloy material with low thermal neutron absorption cross section prepared according to an embodiment of the present invention.

[0020] Figure 3These are microstructure images of refractory medium-entropy alloy materials with low thermal neutron absorption cross sections prepared according to embodiments of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. However, the scope of protection of the present invention is not limited thereto. Unless otherwise specified, all reagents used in the present invention are commercially available analytical grade reagents, and all raw materials used can be purchased through conventional commercial channels.

[0022] Example 1 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y. 25 Zr 25 Nb 25 Mo 25 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in a 5% hydrochloric acid aqueous solution at room temperature for 10 min to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 5×10 -2 Pretreatment was completed by vacuum deoxidation at 1000℃ for 4 hours under Pa conditions.

[0023] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0024] (3) After vacuuming (vacuum degree is 4×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 5 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0025] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are as follows: Figure 1 As shown, curve #1 is the engineering stress-strain curve of the refractory intermediate-entropy alloy material with high strength and low thermal neutron absorption cross section obtained in Example 1. The Y obtained in this example 25 Zr 25 Nb 25 Mo25 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,910 MPa, a compressive strength of 2,762 MPa, and a fracture strain of 22.4%.

[0026] In order to determine the Y obtained in this embodiment 25 Zr 25 Nb 25 Mo 25 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (a), Y 25 Zr 25 Nb 25 Mo 25 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0027] Calculate Y using the mixed-law method. 25 Zr 25 Nb 25 Mo 25 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy material are shown in Table 1. The theoretical melting point of the alloy is equal to the sum of the theoretical melting points of each element multiplied by the atomic percentage of each element; the thermal neutron absorption cross section of the alloy is equal to the sum of the thermal neutron absorption cross sections of each element multiplied by the atomic percentage of each element. The results are shown in Table 1. The theoretical melting point of the refractory medium-entropy alloy material obtained in this embodiment is 2,119°C, and the thermal neutron absorption cross section is 1.27 barn.

[0028] The Y prepared in this embodiment 25 Zr 25 Nb 25 Mo 25 Refractory intermediate-entropy alloys have high theoretical melting points, high room temperature yield strength, and low thermal neutron absorption cross sections, resulting in high safety and reliability. They can be used in key technology fields such as nuclear power, especially as nuclear cladding materials.

[0029] Example 2 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y. 10 Zr 45 Nb 30 Mo 15 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in a 6% hydrochloric acid aqueous solution at room temperature for 8 minutes to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 4×10 -2Pretreatment was completed by vacuum deoxidation at 1050℃ for 2 hours under Pa conditions.

[0030] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0031] (3) After vacuuming (vacuum degree is 3.6×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 6 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0032] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are as follows: Figure 1 As shown, curve #2 is the engineering stress-strain curve of the refractory medium-entropy alloy material with high strength and low thermal neutron absorption cross section obtained in Example 2. The Y2 obtained in this example... 10 Zr 45 Nb 30 Mo 15 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,611 MPa, a compressive strength of 2,551 MPa, and a fracture strain of 24.4%.

[0033] In order to determine the Y obtained in this embodiment 10 Zr 45 Nb 30 Mo 15 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (b), Y 10 Zr 45 Nb 30 Mo 15 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0034] At the same time, Y was observed under a microscope. 10 Zr 45 Nb 30 Mo 15 The microstructure of refractory medium-entropy alloys is shown in the following results. Figure 3As shown in (a), it can be seen that the refractory medium-entropy alloy material prepared by the present invention has a uniform two-phase distribution and no obvious segregation of the structure, indicating that it has good castability.

[0035] Calculate Y using the mixed-law method. 10 Zr 45 Nb 30 Mo 15 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy material are shown in Table 1. The theoretical melting point of the refractory medium-entropy alloy material obtained in this embodiment is 2,123°C, and the thermal neutron absorption cross section is 0.93 barn.

[0036] The material in this embodiment has a high theoretical melting point and a low thermal neutron absorption cross section, which can reduce material damage and radioactive activation caused by neutron irradiation and ensure a long service life under actual working conditions.

[0037] Example 3 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y. 10 Zr 40 Nb 30 Mo 20 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in an 8% hydrochloric acid aqueous solution at room temperature for 5 minutes to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 2.5×10 -2 Pretreatment was completed by vacuum deoxidation at 1100℃ for 3 hours under Pa conditions.

[0038] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0039] (3) After vacuuming (vacuum degree is 2.2×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 7 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0040] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are as follows: Figure 1 As shown, curve #3 is the engineering stress-strain curve of the refractory medium-entropy alloy material with high strength and low thermal neutron absorption cross section obtained in Example 3. The Yg obtained in this example... 10 Zr 40 Nb 30 Mo 20 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,523 MPa, a compressive strength of 2,420 MPa, and a fracture strain of 26.2%.

[0041] In order to determine the Y obtained in this embodiment 10 Zr 40 Nb 30 Mo 20 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (c), Y 10 Zr 40 Nb 30 Mo 20 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0042] At the same time, Y was observed under a microscope. 10 Zr 40 Nb 30 Mo 20 The microstructure of refractory medium-entropy alloys is shown in the following results. Figure 3 As shown in (b), it can be seen that the two-phase structure of the refractory medium-entropy alloy material prepared by the present invention is arranged in an interlaced manner, and no obvious casting defects are observed, indicating that the alloy of the present invention has the potential for large-scale industrial production.

[0043] Calculate Y using the mixed-law method. 10 Zr 40 Nb 30 Mo 20 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy material are shown in Table 1. The theoretical melting point of the refractory medium-entropy alloy material obtained in this embodiment is 2,162°C, and the thermal neutron absorption cross section is 1.04 barn.

[0044] The alloy in this embodiment meets the requirements of special fields such as the nuclear industry for the neutronics properties of materials and has good application prospects.

[0045] Example 4 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y5Zr. 45 Nb 30 Mo20 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in a 10% hydrochloric acid aqueous solution at room temperature for 5 minutes to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 1.5×10 -2 Pretreatment was completed by vacuum deoxidation at 1200℃ for 2 hours under Pa conditions.

[0046] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0047] (3) After vacuuming (vacuum degree is 1.6×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 8 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0048] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are as follows: Figure 1 As shown, curve #3 is the engineering stress-strain curve of the refractory medium-entropy alloy material with high strength and low thermal neutron absorption cross section obtained in Example 3. The Y5Zr obtained in this example... 45 Nb 30 Mo 20 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,628 MPa, a compressive strength of 2,286 MPa, and a fracture strain of 27.4%.

[0049] To determine the Y5Zr obtained in this embodiment 45 Nb 30 Mo 20 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (d), Y5Zr 45 Nb 30 Mo 20 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0050] Meanwhile, Y5Zr was observed under a microscope.45 Nb 30 Mo 20 The microstructure of refractory medium-entropy alloys is shown in the following results. Figure 3 As shown in (c), it can be seen that the refractory medium-entropy alloy material prepared by the present invention has no obvious component segregation and casting defects such as porosity and shrinkage cavities. The two-phase interface is tightly bonded, forming a uniform two-phase composite microstructure.

[0051] Calculate Y5Zr using the hybrid rule method. 45 Nb 30 Mo 20 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy are shown in Table 1. The theoretical melting point of the refractory medium-entropy alloy obtained in this embodiment is 2,179°C, and the thermal neutron absorption cross section is 0.99 barn.

[0052] The alloy of this embodiment has ultra-low thermal neutron absorption characteristics, which can effectively reduce neutron capture and neutron decay loss, and meet the stringent requirements of the nuclear industry and other industries for the neutronics performance of materials.

[0053] Example 5 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Zr. 15 Nb 45 Mo 40 Its preparation method is as follows: (1) The Zr, Nb and Mo raw materials were mechanically polished, then soaked in a 5% hydrochloric acid aqueous solution at room temperature for 10 min to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 5×10 -2 Pretreatment was completed by vacuum deoxidation at 1000℃ for 4 hours under Pa conditions.

[0054] (2) Weigh out Zr, Nb and Mo raw materials according to atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. Ensure that the low melting point element is located at the bottom of the melting device.

[0055] (3) After vacuuming (vacuum degree is 4×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the Zr, Nb and Mo raw materials are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 5 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0056] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are shown in Table 1. The Zr obtained in this embodiment... 15 Nb 45 Mo 40 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,723 MPa, a compressive strength of 2,562 MPa, and a fracture strain of 25.3%.

[0057] To determine the Zr obtained in this embodiment 15 Nb 45 Mo 40 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (e), Zr 15 Nb 45 Mo 40 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0058] Calculate Zr using the hybrid rule method. 15 Nb 45 Mo 40 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy material are shown in Table 1. The theoretical melting point of the alloy is equal to the sum of the theoretical melting points of each principal element multiplied by the atomic percentage of each principal element; the thermal neutron absorption cross section of the alloy is equal to the sum of the thermal neutron absorption cross sections of each principal element multiplied by the atomic percentage of each principal element. The results are shown in Table 1. The theoretical melting point of the Zr-Nb-Mo refractory medium-entropy alloy material obtained in this embodiment is 2,442°C, and the thermal neutron absorption cross section is 1.54 barn.

[0059] The alloy of this embodiment combines ultra-high strength, good plasticity, high melting point and low thermal neutron absorption cross section. It can be adapted to various extreme service environments such as high temperature, high pressure and nuclear radiation without complex modification, providing a new option for high-end refractory structural materials in nuclear industry, aerospace and other fields.

[0060] Example 6 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y. 20 Zr 55 Nb 15 Mo 10 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in a 5% hydrochloric acid aqueous solution at room temperature for 10 min to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 5×10 -2 Pretreatment was completed by vacuum deoxidation at 1000℃ for 4 hours under Pa conditions.

[0061] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0062] (3) After vacuuming (vacuum degree is 4×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 5 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0063] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are shown in Table 1. The Y obtained in this embodiment... 20 Zr 55 Nb 15 Mo 10 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,745 MPa, a compressive strength of 2,621 MPa, and a fracture strain of 23.4%. This indicates that the embodiments of the present invention possess high strength, which endows them with extremely strong load-bearing and deformation resistance capabilities. The high ductility effectively avoids the shortcomings of refractory alloys, which are prone to brittle fracture, and meets the structural load-bearing requirements under extreme environments.

[0064] At the same time, Y was observed under a microscope. 20 Zr 55 Nb 15 Mo 10 The microstructure of refractory medium-entropy alloys is shown in the following results. Figure 3 As shown in (d), there is no obvious component segregation, the two-phase interface is tightly bonded, and the casting performance is good.

[0065] Calculate Y using the mixed-law method. 20 Zr 55 Nb 15 Mo 10The theoretical melting point and thermal neutron absorption cross section of the refractory intermediate-entropy alloy material are shown in Table 1. The theoretical melting point of the alloy is equal to the sum of the theoretical melting points of each principal element multiplied by the atomic percentage of each principal element; the thermal neutron absorption cross section of the alloy is equal to the sum of the thermal neutron absorption cross sections of each principal element multiplied by the atomic percentage of each principal element. 20 Zr 55 Nb 15 Mo 10 The theoretical melting point of the refractory medium-entropy alloy material is 1,959°C, and the thermal neutron absorption cross section is 0.78 barn; this indicates that the alloy in the embodiment of the present invention has excellent high-temperature thermal stability, can be adapted to high-temperature service scenarios, and meets the stringent requirements of the nuclear industry and other industries for the neutron performance of materials.

[0066] Example 7 This embodiment discloses a high-strength, low-thermal-neutron-absorbing refractory medium-entropy alloy material, whose atomic percentage content is expressed as Y. 30 Zr 45 Nb 15 Mo 10 Its preparation method is as follows: (1) The four raw materials Y, Zr, Nb and Mo were mechanically polished, then soaked in a 5% hydrochloric acid aqueous solution at room temperature for 10 min to remove the oxide scale on the surface, then washed with deionized water and dehydrated with anhydrous ethanol, and then the raw materials were subjected to a vacuum of 5×10 -2 Pretreatment was completed by vacuum deoxidation at 1000℃ for 4 hours under Pa conditions.

[0067] (2) Weigh out the four raw materials Y, Zr, Nb and Mo according to their atomic percentage content, and place them in the vacuum melting device in order of melting point from low to high. It is necessary to ensure that the low melting point element is located at the bottom of the melting device.

[0068] (3) After vacuuming (vacuum degree is 4×10) -3 High-purity argon gas (99.9 wt.%) is introduced into the device to maintain a protective atmosphere. The argon gas pressure is lower than the ambient pressure outside the device. Then, the raw materials Y, Zr, Nb and Mo are smelted until completely melted. During the smelting process, magnetic stirring technology is used to mix the metal solution evenly. After cooling and solidification, an ingot is obtained. The ingot is repeatedly turned over 5 times and cooled to room temperature to obtain a refractory medium-entropy alloy with high strength and low thermal neutron absorption cross section.

[0069] Compression tests were conducted using an electronic universal testing machine. The cylindrical specimens had dimensions of Ф6mm × 12mm, and the strain rate was 10. -3 The mechanical properties of the obtained refractory medium-entropy alloy were tested at / s, and the results are shown in Table 1. The Y obtained in this embodiment... 30 Zr 45Nb 15 Mo 10 Refractory medium-entropy alloys possess excellent mechanical properties, with a compressive yield strength of 1,792 MPa, a compressive strength of 2,715 MPa, and a fracture strain of 22.9%.

[0070] In order to determine the Y obtained in this embodiment 30 Zr 45 Nb 15 Mo 10 The composition of the refractory medium-entropy alloy was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown in (f), Y 30 Zr 45 Nb 15 Mo 10 Refractory medium-entropy alloys have a dual-phase structure of HCP+FCC, where HCP is the main phase and FCC is the secondary phase.

[0071] Calculate Y using the mixed-law method. 30 Zr 45 Nb 15 Mo 10 The theoretical melting point and thermal neutron absorption cross section of the refractory medium-entropy alloy material are shown in Table 1. The theoretical melting point of the alloy is equal to the sum of the theoretical melting points of each principal element multiplied by the atomic percentage of each principal element; the thermal neutron absorption cross section of the alloy is equal to the sum of the thermal neutron absorption cross sections of each principal element multiplied by the atomic percentage of each principal element. The results are shown in Table 1. The theoretical melting point of the Y-Zr-Nb-Mo refractory medium-entropy alloy material obtained in this embodiment is 1925°C, and the thermal neutron absorption cross section is 0.89 barn.

[0072] The alloy of this embodiment achieves a synergistic improvement in mechanical properties, microstructure, and comprehensive performance in high temperature and thermal neutronics, exhibiting excellent comprehensive characteristics suitable for extreme service scenarios, and breaking through the limitations of traditional refractory alloys that cannot simultaneously achieve high strength and multi-dimensional service performance.

[0073] Table 1 shows the composition, compressive mechanical properties, theoretical melting point, and thermal neutron absorption cross section of the examples. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section, characterized in that, The general expression for the refractory intermediate-entropy alloy material with the low thermal neutron absorption cross section is Y. a Zr b Nb c Mo d , where a, b, c, d represent the atomic percentage content of each corresponding element, and satisfy the following conditions: 0≤a≤30, 15≤b≤55, 15≤c≤45, 10≤d≤40, a+b+c+d=100.

2. The method for preparing the refractory intermediate-entropy alloy material with low thermal neutron absorption cross section as described in claim 1, characterized in that, The steps are as follows: (1) After grinding and pickling, Y, Zr, Nb and Mo raw materials are cleaned and dehydrated; (2) The raw material that has been dehydrated is vacuum deoxidized, then melted, cooled and solidified to obtain an ingot, the ingot is flipped and melted again, and cooled to room temperature to obtain a refractory medium entropy alloy with a low thermal neutron absorption cross section.

3. The method for preparing a refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section according to claim 2, characterized in that, In step (1), the pickling process involves soaking the sample in a 5-10% hydrochloric acid solution for 5-10 minutes, followed by rinsing with water and dehydration with an organic solvent.

4. The method for preparing a refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section according to claim 2, characterized in that, The vacuum deoxidation conditions in step (2) are: 1000-1200℃, vacuum degree ≤5×10 -2 Keep warm for 2-4 hours under the condition of Pa.

5. The method for preparing a refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section according to claim 2, characterized in that, In step (2), during the smelting process, the raw materials are placed in order of increasing melting point to ensure that the low melting point elements are located at the bottom of the smelting device.

6. The method for preparing a refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section according to claim 2, characterized in that, During the melting process in step (2), a vacuum must be drawn first, with a vacuum degree ≤ 5 × 10⁻⁶. -3 Pa, argon gas is introduced to maintain a protective atmosphere.

7. The method for preparing a refractory intermediate-entropy alloy material with a low thermal neutron absorption cross section according to claim 2, characterized in that, During the smelting process in step (2), the ingot is flipped 5-8 times.

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