Neutron-transparent alloy for high-temperature neutron scattering experiments

Abstract

This invention belongs to the field of materials science and engineering, and relates to an NS-TNV40 neutron-transparent alloy for high-temperature neutron scattering experiments. The alloy's composition, by weight percentage, is 39.24% Ti, 39.24% Nb, and 21.52% V. Its preparation includes batching, melting, homogenization, and forging. The alloy has a theoretical melting point of 1716℃, exhibits no neutron diffraction peaks after holding at 1000℃ for 100 hours, and demonstrates excellent high-temperature stability. It maintains a single-phase structure without phase transformation after 100 hours of service at 1000℃. It also exhibits good high-temperature oxidation resistance, with oxidation weight gain lower than that of high-purity V and VNi alloys. Mechanically, it combines high strength and high plasticity. This alloy can avoid interference from the scattering signals of the sample container itself, improve the quality of neutron scattering data, meet the requirements of high-temperature in-situ experiments, and promote the development of high-temperature neutron scattering experimental technology.

Description

Technical Field

[0001] This invention belongs to the field of materials science and engineering, and specifically relates to a neutron-transparent alloy for high-temperature neutron scattering experiments. Background Technology

[0002] High-temperature neutron scattering (HTNS) experiments, as a key technique for exploring the microstructure and dynamic properties of matter, play an irreplaceable role in many fields such as materials science and condensed matter physics. During HTNS experiments, the test samples are diverse in form, encompassing solids, liquids, and powders, requiring specialized sample containers placed within the test neutron beam. During the experiment, the neutron beam passes through the container and interacts with the sample, thereby acquiring neutron scattering data to analyze the sample's microstructure and dynamic properties. However, the scattering signal from the sample container itself can significantly interfere with data analysis, severely impacting data quality. Simultaneously, the complex structures and metallic components in the sample environment further exacerbate the influence of external signals on the neutron scattering data. Therefore, strictly controlling the scattering background to avoid the influence of various background signal sources on the neutron scattering data quality has become a critical problem that urgently needs to be solved in high-temperature neutron scattering experiments.

[0003] Currently, vanadium, TiZr, and VNi alloys are commonly used internationally as sample containers. However, there are no reports internationally on neutron-transparent alloys suitable for high-temperature experimental environments above 800°C, highlighting the lack of suitable neutron-transparent alloys for high-temperature neutron scattering experiments. Specifically, TiZr alloys have a neutron melting point of only 1550°C. Above 750°C, they soften and recrystallize, severely limiting their application potential under high-temperature conditions and failing to meet the requirements of experiments above 800°C. Furthermore, vanadium exhibits significant embrittlement above 1200°C, severely restricting its reusability and economic viability; and above 675°C, it undergoes rapid and catastrophic oxidation, further limiting its application in high-temperature environments. Therefore, developing a neutron-transparent alloy suitable for high-temperature experimental environments above 800°C, with no neutron diffraction peaks and good high-temperature stability, is urgently needed. Summary of the Invention

[0004] To address the aforementioned problems, this invention aims to provide a neutron-transparent alloy for high-temperature neutron scattering experiments. This alloy is primarily used as a sample container and neutron beam window material in high-temperature neutron scattering experiments. It can effectively avoid the influence of the scattering signals of the sample container and metal components in the sample environment on the quality of neutron scattering data, meeting the stringent requirements of high-temperature in-situ experiments for materials with high temperature resistance, high stability, and no neutron diffraction peaks. This provides key material support for high-temperature neutron scattering experiments and promotes the in-depth application and development of neutron scattering technology under high-temperature conditions.

[0005] The technical solution adopted in this invention is: a neutron-transparent alloy for high-temperature neutron scattering experiments, wherein the neutron-transparent alloy without neutron diffraction peaks is NS-TNV40 alloy, and the composition of NS-TNV40 alloy by weight percentage is: Ti 39.24%, Nb 39.24%, V 21.52%; The preparation method of the neutron-transparent alloy without neutron diffraction peaks includes the following steps: In the batching stage: The alloy raw materials are prepared by mixing bulk elemental Ti with a purity of better than 99.99%, elemental Nb with a purity of better than 99.99%, and elemental V with a purity of better than 99.999% in a ratio of 39.24Ti, 39.24Nb, and 21.52V (wt%), and the surface oxide layer is removed by cleaning with 10% HCl solution. Melting stage: Vacuum suspension melting is adopted. First, Nb / V is placed in the furnace for pre-melting to obtain NbV alloy ingots. Then, the NbV alloy ingots are melted together with Ti feedstock to prepare kilogram-level alloy ingots with uniform composition. Homogenization stage: The alloy ingot is placed in a high-temperature furnace and subjected to vacuum annealing or annealing under Ar gas protection for more than 24 hours at 1000℃-1400℃ to achieve homogenization. Forging stage: The homogenized bar stock is forged at a temperature above 1000℃ to obtain bar stock or plate of ideal size; The theoretical melting point of the neutron-free diffraction peak neutron transparent alloy is 1716℃. It retains the neutron-free diffraction peak characteristics even after being held at 1000℃ for 100 hours, and has excellent high-temperature stability and oxidation resistance.

[0006] During the smelting stage, the Nb / V pre-smelting power was 230kW, the smelting time was 5 minutes, and the furnace was cooled for 1 hour before being removed from the furnace; the second and third smelting powers were 250kW and 200kW respectively, and the refining time for each smelting was 10 minutes, with a cooling time of 1 hour for each.

[0007] The vacuum level during the homogenization process is better than 5×10^-3 Pa.

[0008] After being held at 1000℃ for different times, the grains of this alloy gradually grew from fine, fragmented grains into regular polygons, and the grain boundaries became straighter, which conforms to the trend of minimizing system energy during grain growth.

[0009] After being held at 1000℃ for different times, the alloy showed no other precipitated phases, maintained a single-phase structure, and exhibited excellent high-temperature stability.

[0010] The alloy exhibits excellent oxidation resistance, with a lower oxidation weight gain than high-purity V and VNi alloys after 10 hours of oxidation in air at 1000℃.

[0011] This alloy exhibits excellent machinability at room temperature, which meets the requirements of high-temperature in-situ neutron scattering experiments for sample containers and neutron beam windows.

[0012] This alloy is suitable for high-temperature neutron scattering experimental environments above 800℃, and can be used as a sample container and neutron beam window material for high-temperature sample environments. The beneficial effects of this invention are mainly reflected in the following: The NS-TNV40 alloy prepared by this invention exhibits no neutron diffraction peaks under high-temperature experimental conditions, effectively avoiding interference from the scattering signal of the sample container itself on neutron scattering data analysis. This significantly improves the quality of neutron scattering data and provides a reliable guarantee for accurate analysis of the sample's microstructure and dynamic properties. Neutron diffraction spectra of the NS-TNV40 alloy after treatment at 1000℃ for different times show no neutron diffraction peaks, meeting the requirement of no background signal from the sample container in high-temperature neutron scattering experiments.

[0013] The alloy of this invention maintains stable performance after 100 hours of operation at 1000℃, meeting service requirements. Compared with previously developed TiTaAl alloys, its high-temperature stability is significantly improved. It retains a single-phase structure after 100 hours of operation at 1000℃, with no other precipitated phases forming. Figure 3 As shown, by comparing the XRD patterns obtained after holding at 1000℃ for different times, the TiTaAl alloy precipitated an α phase on top of the original β phase after 24 hours of holding, while the NS-TNV40 alloy did not undergo a phase transformation and maintained a single-phase structure, fully demonstrating its excellent high-temperature stability. Simultaneously, the grains gradually grew from fine, fragmented grains to more regular polygons, and the grain boundaries became straighter, consistent with the trend of minimizing system energy during grain growth, further proving its structural stability at high temperatures.

[0014] The high-temperature oxidation resistance test of the present invention shows that, after oxidation at 1000°C in an air atmosphere for 10 hours, the oxidation weight gain of the NS-TNV40 alloy is lower than that of high-purity V and VNi alloys. This indicates that the alloy has better oxidation resistance than commonly used V and VNi alloys, which can effectively reduce the impact of oxidation reaction on the alloy performance under high-temperature experimental conditions, extend the service life of the alloy, and reduce experimental costs.

[0015] Compared with the mechanical properties of current neutron-transparent alloys, the NS-TNV40 alloy exhibits superior high strength and high ductility. This allows the alloy to meet the requirements of high-temperature neutron scattering experiments for sample containers and neutron beam windows, while also possessing good machinability and performance characteristics, enabling it to better adapt to different experimental needs and processing techniques.

[0016] The NS-TNV40 alloy prepared by this invention can meet the requirements of high-temperature in-situ experiments, providing an ideal material choice for high-temperature neutron scattering experiments, promoting the development and application of high-temperature neutron scattering experimental technology, and helping to carry out more in-depth research in the fields of materials science and condensed matter physics, exploring the microstructure and dynamic properties of matter under high-temperature environments. Attached Figure Description

[0017] Figure 1 The Pandat phase diagram calculation in this invention verifies that the theoretical melting point of the NS-TNV40 alloy is 1716℃. Figure 2 These are the neutron diffraction spectra of the NS-TNV40 alloy after treatment at 1000℃ for different times in this invention; Figure 3 These are the XRD patterns of NS-TNV40 alloy and TiTaAl alloy at 1000℃ for different holding times in this invention; Figure 4 shows the EBSD inverse pole figures of the NS-TNV40 alloy with a theoretical melting point of 1716℃ under different holding times. Figures a, b, c, and d are the holding times at 1000℃ for 0h, 24h, 48h, and 100h, respectively. Figure 5 The grain size distribution diagrams of NS-TNV40 alloy at different holding times in this invention are shown in a, b, c, and d, respectively, for holding at 1000℃ for 0h, 24h, 48h, and 100h. Figure 6 This is a comparison curve of the weight gain of NS-TNV40 alloy with V and VNi oxidation in this invention. Detailed Implementation

[0018] This invention provides a method for preparing NS-TNV40 alloy, a neutron-transparent alloy for high-temperature neutron scattering experiments. This alloy has a uniform composition, a theoretical melting point of 1716℃, and retains no neutron diffraction peaks even after holding at 1000℃ for 100 hours. It also exhibits excellent high-temperature stability and oxidation resistance, meeting the requirements for sample containers and neutron beam windows in high-temperature in-situ neutron scattering experiments. The specific embodiments of this invention are described in detail below with reference to the accompanying drawings: like Figure 1-6 As shown, the NS-TNV40 alloy prepared by this invention is suitable for high-temperature neutron scattering experimental environments above 800℃, and can be used as a sample container and neutron beam window material. Figure 1 The theoretical melting point of NS-TNV40 alloy is shown to be 1716℃, proving that the alloy has high thermal stability and is suitable for high-temperature environments; Figure 2 Neutron diffraction spectra of NS-TNV40 alloy after treatment at 1000℃ for different times: The neutron diffraction of NS-TNV40 alloy after being held at 1000℃ for different times (e.g., 0h, 24h, 48h, 100h) is shown. The results show that the alloy still maintains the characteristic of no neutron diffraction peaks after being held at high temperature for a long time, which is crucial for the data quality of neutron scattering experiments. Figure 3 In this study, XRD patterns of NS-TNV40 alloy and TiTaAl alloy held at 1000℃ for different times were compared. The results showed that TiTaAl alloy precipitated an α phase after 24 hours of holding, while NS-TNV40 alloy maintained a single-phase structure without the formation of other precipitates, demonstrating its excellent high-temperature stability. Figure 4 EBSD inverse pole figures of NS-TNV40 alloy at different holding times: The figures show the EBSD inverse pole figures of NS-TNV40 alloy after holding at 1000℃ for 0h, 24h, 48h and 100h. It can be seen from the figure that as the holding time increases, the grains gradually grow from fine fragmented grains to regular polygons, and the grain boundaries become straighter, which is consistent with the trend of minimizing system energy during grain growth. Figure 5 The grain size distribution diagram of NS-TNV40 alloy under different holding times further quantifies the grain size distribution of NS-TNV40 alloy under different holding times, and intuitively shows the grain growth process. Figure 6 The oxidation weight gain curve of NS-TNV40 alloy shows the oxidation weight gain of NS-TNV40 alloy after 10 hours of oxidation in air at 1000℃. Compared with high-purity V and VNi alloys, the oxidation weight gain of NS-TNV40 alloy is significantly reduced, indicating its excellent oxidation resistance. The following are specific embodiments of the present invention: The alloy composition design in this embodiment is as follows: The composition of the NS-TNV40 alloy in this embodiment, by weight percentage, is: Ti 39.24%, Nb 39.24%, and V 21.52%. This ratio was obtained through precise calculation and multiple experimental verifications, aiming to achieve stable performance of the alloy under high-temperature conditions and neutron-free diffraction peak characteristics.

[0019] The preparation process steps in this embodiment are as follows: S1, Ingredient Preparation Stage: Bulk elemental Ti (purity better than 99.99%), elemental Nb (purity better than 99.99%), and elemental V (purity better than 99.999%) were selected as raw materials. Each raw material was precisely weighed according to the ratio of 39.24Ti - 39.24Nb - 21.52V (wt%). The raw materials were washed with a 10% HCl solution to remove the surface oxide layer and ensure the purity of the raw materials.

[0020] S2, Smelting Stage: Vacuum suspension melting technology was employed. First, Nb / V was placed in a furnace for pre-melting. The pre-melting power was 230 kW, and the melting time was 5 minutes. The power was then slowly reduced to a minimum, and the mixture was cooled for 1 hour before being removed from the furnace. During the melting process, a vacuum level better than 5 × 10⁻³ Pa was maintained. The pre-melted NbV alloy ingot was then placed in the furnace again with Ti feedstock for melting. The second melting power was 250 kW, and the third melting power was reduced to 200 kW. Each melting and refining process lasted 10 minutes, with a cooling time of 1 hour for each stage, ultimately producing kilogram-sized alloy ingots with uniform composition.

[0021] S3, Homogenization stage: The prepared alloy ingot is placed in a high-temperature furnace and subjected to vacuum annealing (vacuum degree better than 5×10^-3Pa) for more than 24 hours in the temperature range of 1000℃-1400℃ or annealing under Ar gas protection to achieve alloy homogenization.

[0022] S4, Forging Stage: The homogenized bars are forged at temperatures above 1000℃ to obtain bars or plates of ideal dimensions through plastic deformation, in order to meet different experimental requirements.

[0023] The technical effects of the alloy produced in this embodiment were verified, and the specific verification results are shown below: High-temperature stability verification: The theoretical melting point of the NS-TNV40 alloy was calculated to be 1716℃ using the Pandat phase diagram (see...). Figure 1 This indicates that the alloy possesses extremely high thermal stability. Experiments show that after holding at 1000℃ for different times (0h, 24h, 48h, 100h), observations using EBSD inverse pole figures (see...) demonstrate that... Figure 4 The study revealed that the alloy grains gradually grew from fine, fragmented grains to regular polygons, with increasingly straight grain boundaries, consistent with the energy minimization trend during grain growth and demonstrating excellent high-temperature stability. Furthermore, XRD pattern analysis (see...) Figure 3 The NS-TNV40 alloy showed no other precipitated phases after being held at 1000℃ for different times, maintaining a single-phase structure, which further verified its high-temperature stability.

[0024] Verification of neutron-free diffraction peak characteristics: After holding at 1000℃ for different times, neutron diffraction spectra were measured (see...). Figure 2 This confirms that the NS-TNV40 alloy does not produce neutron diffraction peaks, meeting the requirements of high-temperature neutron scattering experiments for no interference with the sample container and neutron beam window.

[0025] Antioxidant performance verification: After oxidation in air at 1000℃ for 10 hours, the oxidation weight gain curve was analyzed (see...). Figure 6 It was found that the oxidation weight gain of NS-TNV40 alloy was lower than that of high-purity V and VNi alloys, indicating that it has excellent oxidation resistance.

[0026] The NS-TNV40 alloy prepared by this invention is suitable for high-temperature neutron scattering experimental environments above 800℃. It can be used as a sample container and neutron beam window material, effectively avoiding the influence of external signals on the quality of neutron scattering data and improving the accuracy and reliability of experimental data.

[0027] In summary, this invention has successfully developed an NS-TNV40 alloy with no neutron diffraction peaks, good high-temperature stability, and excellent oxidation resistance through precise alloy composition design and efficient preparation process, providing an ideal material solution for high-temperature neutron scattering experiments.

Claims

1. A neutron-transparent alloy for high-temperature neutron scattering experiments, characterized in that, The neutron-free diffraction peak neutron-transparent alloy is NS-TNV40 alloy. The composition of NS-TNV40 alloy by weight percentage is: Ti 39.24%, Nb 39.24%, V 21.52%. The preparation method of the neutron-transparent alloy without neutron diffraction peaks includes the following steps: In the batching stage: The alloy raw materials are prepared by mixing bulk elemental Ti with a purity of better than 99.99%, elemental Nb with a purity of better than 99.99%, and elemental V with a purity of better than 99.999% in a ratio of 39.24Ti, 39.24Nb, and 21.52V (wt%), and the surface oxide layer is removed by cleaning with 10% HCl solution. Melting stage: Vacuum suspension melting is adopted. First, Nb / V is placed in the furnace for pre-melting to obtain NbV alloy ingots. Then, the NbV alloy ingots are melted together with Ti feedstock to prepare kilogram-level alloy ingots with uniform composition. Homogenization stage: The alloy ingot is placed in a high-temperature furnace and subjected to vacuum annealing or annealing under Ar gas protection for more than 24 hours at 1000℃-1400℃ to achieve homogenization. Forging stage: The homogenized bar stock is forged at a temperature above 1000℃ to obtain bar stock or plate of ideal size; The theoretical melting point of the neutron-free diffraction peak neutron transparent alloy is 1716℃. It retains the neutron-free diffraction peak characteristics even after being held at 1000℃ for 100 hours, and has excellent high-temperature stability and oxidation resistance.

2. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 1, characterized in that, During the smelting stage, the Nb / V pre-smelting power was 230kW, the smelting time was 5 minutes, and the furnace was cooled for 1 hour before being removed from the furnace; the second and third smelting powers were 250kW and 200kW respectively, and the refining time for each smelting was 10 minutes, with a cooling time of 1 hour for each.

3. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 3, characterized in that, The vacuum level during the homogenization process is better than 5×10^-3 Pa.

4. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 1, characterized in that, After being held at 1000℃ for different times, the grains of this alloy gradually grew from fine, fragmented grains into regular polygons, and the grain boundaries became straighter, which conforms to the trend of minimizing system energy during grain growth.

5. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 1, characterized in that, After being held at 1000℃ for different times, the alloy showed no other precipitated phases, maintained a single-phase structure, and exhibited excellent high-temperature stability.

6. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 1, characterized in that, The alloy exhibits excellent oxidation resistance, with a lower oxidation weight gain after 10 hours of oxidation in air at 1000°C compared to high-purity V and VNi alloys used in conventional neutron scattering experiments.

7. The neutron-transparent alloy for high-temperature neutron scattering experiments according to claim 1, characterized in that, This alloy exhibits excellent machinability at room temperature, meeting the processing requirements for sample containers and neutron beam windows in high-temperature in-situ neutron scattering experiments.

8. A neutron-transparent alloy for high-temperature neutron scattering experiments according to any one of claims 1 to 9, characterized in that, This alloy is suitable for high-temperature neutron scattering experimental environments above 800℃, and can be used as a sample container and neutron beam window material in high-temperature sample environments.

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