A UMoNbTi-based lightweight uranium-containing high-entropy alloy

Abstract

This invention discloses a lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system, containing uranium. It belongs to the field of high-entropy alloy materials. The alloy composition is: uranium: 15-60%; molybdenum: 10-35%; niobium: 10-35%; titanium: 15-50%; zirconium: 0.1-10%; aluminum: 0.01-10%, with the balance being unavoidable impurities. Currently, research on the microstructure stability, tensile strength, and radiation embrittlement resistance of MoNbTi alloys under high temperature and irradiation environments is almost nonexistent. Furthermore, other studies have not given sufficient attention to U-containing high-entropy alloy fuels. This invention proposes a lightweight, high-entropy alloy based on the U-Mo-Nb-Ti system, fully considering the special role of uranium, thereby achieving structural and functional integration in the high-entropy alloy.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy alloy materials, and in particular relates to a high-entropy alloy containing uranium and its preparation method. Background Technology

[0002] High-entropy alloys have attracted much attention due to their excellent properties such as high strength, high hardness, and corrosion resistance, and are considered to have broad application prospects in fields such as ultra-high temperature materials, high-performance structural materials, low-temperature service materials, and lightweight aerospace materials. The development of lightweight materials, in particular, benefits from the unique design concept of multi-principal high-entropy alloys, opening up new design ideas. Lightweight high-entropy alloys are typically designed and prepared by combining lightweight elements (Al, Ti, Mg, etc.) with transition elements (V, Nb, Mn, etc.). For example, Stepanov et al. prepared an AlNbTiV lightweight high-entropy alloy with a single-phase BCC structure through arc melting, achieving a yield strength of 1020 MPa at room temperature while exhibiting excellent high-temperature performance; Zhang et al. prepared a series of single-phase BCC structure TiAlCrVNb alloys through arc melting, in which Ti... 60 (AlCrVNb) 40 The yield strength at room temperature reaches 960 MPa, and the tensile fracture strain reaches 28%.

[0003] To meet the specific requirements of nuclear power miniaturization and portability, reactor types such as heat pipe reactors and lead-cooled fast reactors have been developed. Taking heat pipe reactors as an example, the service environment of metallic structural materials transitions from the hot end to the cold end, with service temperatures ranging from several hundred degrees Celsius to 1000 degrees Celsius. Therefore, the structural materials used must possess excellent high-temperature mechanical properties, machinability, and resistance to radiation damage. However, traditional nickel-based alloys are gradually approaching their design limits, necessitating the development of revolutionary new materials to meet service requirements. Encouragingly, newly developed refractory high-entropy alloys exhibit excellent mechanical properties and radiation resistance, showing broad prospects and potential for application in space nuclear power systems.

[0004] MoNbTi alloys exhibit comprehensive properties among developed refractory alloys, including lightweight, high strength and plasticity, and resistance to high-temperature softening. However, research on the microstructure stability, tensile strength, and radiation embrittlement resistance of these alloys under high-temperature and irradiation environments is currently almost nonexistent. Therefore, a systematic study of the microstructure stability, high-temperature mechanical properties, and radiation resistance of MoNbTi refractory high-entropy alloys is urgently needed to provide theoretical support and scientific basis for their future practical applications in space reactors.

[0005] There are three structures of U. The γ-U structure with a BCC structure exhibits ideal symmetry and properties at high temperatures. Alloying elements such as Zr, Ti, Mo, and Nb generally have wide solubility in the BCC structure of γ-U. Zr and Nb can completely dissolve with U at high temperatures to form the γ phase. Ti can dissolve in the U matrix and form the γ phase at temperatures above 725 °C. The maximum solubility of Mo in γ-U is 21.2 wt.%.

[0006] In summary, developing high-entropy alloys based on the U-Mo-Nb-Ti system, and fully considering the special role of U, to achieve structural and functional integration of uranium-containing high-entropy alloys, is of great significance for developing lightweight uranium-containing high-entropy alloys and promoting the safe development of the nuclear materials field. Summary of the Invention

[0007] To address the bottleneck issue that typical BCC-structured refractory high-entropy alloys such as TaNbMoW and TaNbMoWV contain a large amount of high-density metallic elements, resulting in high alloy density, high cost, and poor room-temperature plasticity, making them unsuitable for use as structural materials, and considering that other studies have not given sufficient attention to U-containing high-entropy alloys, this invention proposes a lightweight high-entropy alloy based on the U-Mo-Nb-Ti system, and fully considers the special role of U element, thereby achieving the integration of structure and function of the high-entropy alloy.

[0008] A lightweight, structurally functional, integrated high-entropy alloy containing uranium elements based on the U-Mo-Nb-Ti system, the composition of which by atomic percentage is: uranium: 15-60%; molybdenum: 10-35%; niobium: 10-35%; titanium: 15-50%; zirconium: 0.1-10%; aluminum: 0.01-10%, with the balance being unavoidable impurities.

[0009] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: 15-30%; molybdenum: 10-35%; niobium: 10-35%; titanium: 19.89-50%; zirconium: 3-10%; aluminum: 2-10%; and the balance being unavoidable impurities.

[0010] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 15%; Molybdenum: 10%; Niobium: 10%; Titanium: 50%; Zirconium: 5%; Aluminum: 10%, with the balance being unavoidable impurities.

[0011] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 60%; Molybdenum: 10%; Niobium: 10%; Titanium: 15%; Zirconium: 3%; Aluminum: 2%, with the balance being unavoidable impurities.

[0012] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 15-30%; Molybdenum: 12-35%; Niobium: 10-35%; Titanium: 15-50%; Zirconium: 0.1-10%; Aluminum: 0.01-5%; with the balance being unavoidable impurities.

[0013] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 30%; Molybdenum: 35%; Niobium: 10%; Titanium: 15%; Zirconium: 5%; Aluminum: 5%, with the balance being unavoidable impurities.

[0014] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 15-30%; Molybdenum: 12-15%; Niobium: 11-35%; Titanium: 19.89-50%; Zirconium: 0.1-10%; Aluminum: 0.01-2%, with the balance being unavoidable impurities.

[0015] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 30%; Molybdenum: 15%; Niobium: 35%; Titanium: 19.89%; Zirconium: 0.1%; Aluminum: 0.01%, with the balance being unavoidable impurities.

[0016] Further improvements and optimizations to the above technical solution, with the following atomic percentage composition: Uranium: 15%; Molybdenum: 12%; Niobium: 11%; Titanium: 50%; Zirconium: 10%; Aluminum: 2%, with the balance being unavoidable impurities.

[0017] A method for preparing a lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements specifically includes the following steps:

[0018] (1) Prepare raw materials: Weigh the required alloy raw materials according to the U-Mo-Nb-Ti-Zr-Al high-entropy alloy ratio;

[0019] (2) Arc melting: Under the protection of protective gas, U, Mo, Nb, Ti, Zr and Al powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly melted five times, and the samples are turned over after each melting; in order to avoid the influence of melting time and melting current difference on the microstructure and properties of the samples, each sample is kept in the melting state for 1 minute after all alloy elements are completely melted into liquid state before the current is turned off; to ensure that the surface of all samples remains bright after melting, that is, the alloy does not undergo obvious oxidation during the melting preparation process.

[0020] The aforementioned uranium-containing, U-Mo-Nb-Ti based, structurally and functionally integrated high-entropy alloy, which can be used as nuclear fuel, has a compressive yield strength of 720–1250 MPa and a compressibility of >70%.

[0021] Compared with the prior art, the progress and beneficial effects of this invention are as follows:

[0022] This invention proposes a lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium. Due to the addition of U, the alloy exhibits significantly improved strength at room temperature compared to the traditional BCC structure multi-principal element alloy MoNbTi. Furthermore, the addition of Ti maintains a low density. The inclusion of Nb and Al enhances the alloy's high-temperature oxidation resistance while preserving high yield strength. Therefore, this invention, based on the U-Mo-Nb-Ti system, achieves structural and functional integration of a high-entropy alloy by fully considering the unique roles of U and Ti, which is of great significance for the development and application of lightweight high-entropy alloys. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0024] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions. The invention will be further described below in conjunction with specific embodiments.

[0025] Example 1

[0026] A U-Mo-Nb-Ti uranium-containing high-entropy alloy, specifically composed of: 15 at.%U, 10%Mo, 10%Nb, 50%Ti, 5%Zr, 10%Al, with the remainder being unavoidable impurity elements.

[0027] The preparation method of the uranium-containing high-entropy alloy in this embodiment is as follows:

[0028] (1) Prepare raw materials: Weigh the required alloy raw materials according to the ratio of uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy. The specific alloy composition is: 15 at.% U, 10% Mo, 10% Nb, 50% Ti, 5% Zr, 10% Al;

[0029] (2) Arc melting: Under the protection of a protective gas, U, Mo, Nb, Ti, Zr, and Al powders were rapidly heated and melted. To obtain alloy ingots with uniform composition, all samples were repeatedly melted five times, and the samples were turned over after each melting. To avoid the possible influence of melting time and melting current differences on the microstructure and properties of the samples, the current was turned off directly after all alloying elements were completely melted into a liquid state for 1 minute during each melting of each sample.

[0030] The mechanical property tests of the uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy ingot prepared in this embodiment show that the compressive yield strength is 720 MPa and the compression ratio is >70%, exhibiting good strength and plasticity matching characteristics.

[0031] Example 2

[0032] A U-Mo-Nb-Ti uranium-containing high-entropy alloy has the following composition: 60 at.%U, 10% Mo, 10% Nb, 15% Ti, 3% Zr, 2% Al, with the remainder being unavoidable impurity elements.

[0033] The preparation method of the uranium-containing high-entropy alloy in this embodiment is as follows:

[0034] (1) Prepare raw materials: Weigh the required alloy raw materials according to the proportion of uranium-containing high-entropy alloy. The specific alloy composition is: 60 at.% U, 10% Mo, 10% Nb, 15% Ti, 3% Zr, 2% Al;

[0035] (2) Arc melting: Under the protection of a protective gas, U, Mo, Nb, Ti, Zr, and Al powders were rapidly heated and melted. To obtain alloy ingots with uniform composition, all samples were repeatedly melted five times, and the samples were turned over after each melting. To avoid the possible influence of melting time and melting current differences on the microstructure and properties of the samples, the current was turned off directly after all alloying elements were completely melted into a liquid state for 1 minute during each melting of each sample.

[0036] The mechanical property tests of the uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy ingots prepared in this embodiment show that the compressive yield strength is 1250 MPa and the compression ratio is >70%, exhibiting good strength after sacrificing a small amount of plasticity.

[0037] Example 3

[0038] A U-Mo-Nb-Ti uranium-containing high-entropy alloy, specifically composed of: 30 at.%U, 35% Mo, 10% Nb, 15% Ti, 5% Zr, 5% Al, with the remainder being unavoidable impurity elements.

[0039] The preparation method of the uranium-containing high-entropy alloy in this embodiment is as follows:

[0040] (1) Prepare raw materials: Weigh the required alloy raw materials according to the proportion of uranium-containing high-entropy alloy. The specific alloy composition is: 30 at.% U, 35% Mo, 10% Nb, 15% Ti, 5% Zr, 5% Al;

[0041] (2) Arc melting: Under the protection of a protective gas, U, Mo, Nb, Ti, Zr, and Al powders were rapidly heated and melted. To obtain alloy ingots with uniform composition, all samples were repeatedly melted five times, and the samples were turned over after each melting. To avoid the possible influence of melting time and melting current differences on the microstructure and properties of the samples, the current was turned off directly after all alloying elements were completely melted into a liquid state for 1 minute during each melting of each sample.

[0042] The mechanical property tests of the uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy ingots prepared in this embodiment show that the compressive yield strength is 1050 MPa and the compression ratio is >70%, exhibiting good strength after sacrificing a small amount of plasticity.

[0043] Example 4

[0044] A U-Mo-Nb-Ti uranium-containing high-entropy alloy has the following composition: 30 at.%U, 15% Mo, 35%Nb, 19.89% Ti, 0.1% Zr, 0.01% Al, with the remainder being unavoidable impurity elements.

[0045] The preparation method of the uranium-containing high-entropy alloy in this embodiment is as follows:

[0046] (1) Prepare raw materials: Weigh the required alloy raw materials according to the proportion of uranium-containing high-entropy alloy. The specific alloy composition is: 30 at.% U, 15% Mo, 35% Nb, 19.89% Ti, 0.1% Zr, 0.01% Al;

[0047] (2) Arc melting: Under the protection of a protective gas, U, Mo, Nb, Ti, Zr, and Al powders were rapidly heated and melted. To obtain alloy ingots with uniform composition, all samples were repeatedly melted five times, and the samples were turned over after each melting. To avoid the possible influence of melting time and melting current differences on the microstructure and properties of the samples, the current was turned off directly after all alloying elements were completely melted into a liquid state for 1 minute during each melting of each sample.

[0048] The mechanical property tests of the uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy ingots prepared in this embodiment show that the compressive yield strength is 980 MPa and the compression ratio is >70%, exhibiting good characteristics of both strength and plasticity.

[0049] Example 5

[0050] A U-Mo-Nb-Ti uranium-containing high-entropy alloy has the following composition: 15 at.%U, 12% Mo, 11% Nb, 50% Ti, 10% Zr, 2% Al, with the remainder being unavoidable impurity elements.

[0051] The preparation method of the uranium-containing high-entropy alloy in this embodiment is as follows:

[0052] (1) Prepare raw materials: Weigh the required alloy raw materials according to the proportion of uranium-containing high-entropy alloy. The specific alloy composition is: 15 at.% U, 12% Mo, 11% Nb, 50% Ti, 10% Zr, 2% Al;

[0053] (2) Arc melting: Under the protection of a protective gas, U, Mo, Nb, Ti, Zr, and Al powders were rapidly heated and melted. To obtain alloy ingots with uniform composition, all samples were repeatedly melted five times, and the samples were turned over after each melting. To avoid the possible influence of melting time and melting current differences on the microstructure and properties of the samples, the current was turned off directly after all alloying elements were completely melted into a liquid state for 1 minute during each melting of each sample.

[0054] The mechanical property tests of the uranium-containing high-entropy U-Mo-Nb-Ti-Zr-Al alloy ingots prepared in this embodiment show that the compressive yield strength is 880 MPa and the compression ratio is >70%, exhibiting good plasticity.

[0055] The present invention provides a uranium-containing high-entropy U-Mo-Nb-Ti alloy and its preparation method, which has the following advantages over existing materials.

[0056] 1. Due to the addition of U, the high-entropy alloy exhibits a significant increase in yield strength at room temperature compared to the multi-principal-component BCC structure MoNbTi alloy. For example, the tensile yield strength of the U15-Mo10-Nb10-Ti50-Zr5-Al10 alloy with a U content of 15 at.% is ~720 MPa, while the tensile yield strength of the U60-Mo10-Nb10-Ti15-Zr3-Al2 alloy increases to ~1250 MPa after increasing the U content to 60 at.%.

[0057] 2. The addition of Ti and Al elements regulates the alloy phase composition, which improves the mechanical properties of the alloy while maintaining a low density, resulting in higher strength and performance, making it applicable to many nuclear fields.

[0058] 3. Due to the addition of high U content, U-Mo-Nb-Ti high-entropy alloys can also achieve the integration of structure and function of uranium-containing high-entropy alloys, thus providing the best candidate material for the field of lightweight high-entropy alloys with both high strength and toughness and good radiation resistance, and realizing the integration of structure and function.

Claims

1. A lightweight, structurally and functionally integrated high-entropy alloy containing uranium elements based on the U-Mo-Nb-Ti system, characterized in that, Its composition by atomic percentage is as follows: uranium: 15-60%; molybdenum: 10-35%; niobium: 10-35%; titanium: 15-50%; zirconium: 0.1-10%; aluminum: 0.01-10%, with the balance being unavoidable impurities.

2. The lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 1, characterized in that, Its composition by atomic percentage is: 15-30%; molybdenum: 10-35%; niobium: 10-35%; titanium: 19.89-50%; zirconium: 3-10%; aluminum: 2-10%; and the balance is unavoidable impurities.

3. The lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 2, characterized in that, Its composition by atomic percentage is: uranium: 15%; Molybdenum: 10%; Niobium: 10%; Titanium: 50%; Zirconium: 5%; Aluminum: 10%.

4. A lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 1, characterized in that, Its composition by atomic percentage is: uranium: 60%; Molybdenum: 10%; Niobium: 10%; Titanium: 15%; Zirconium: 3%; Aluminum: 2%.

5. The lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 1, characterized in that, Its composition by atomic percentage is as follows: uranium: 15-30%; molybdenum: 12-35%; niobium: 10-35%; titanium: 15-50%; zirconium: 0.1-10%; aluminum: 0.01-5%; with the balance being unavoidable impurities.

6. The lightweight, structurally functional, integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 5, characterized in that, Its composition by atomic percentage is: uranium: 30%; Molybdenum: 35%; Niobium: 10%; Titanium: 15%; Zirconium: 5%; Aluminum: 5%.

7. The lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 1, characterized in that, Its composition by atomic percentage is: uranium: 15-30%; Molybdenum: 12-15%; Niobium: 11-35%; Titanium: 19.89-50%; Zirconium: 0.1-10%; Aluminum: 0.01-2%; Balance: unavoidable impurities.

8. A lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 7, characterized in that, Its composition by atomic percentage is: uranium: 30%; Molybdenum: 15%; Niobium: 35%; Titanium: 19.89%; Zirconium: 0.1%; Aluminum: 0.01%.

9. A lightweight, structurally and functionally integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements according to claim 7, characterized in that, Its composition by atomic percentage is: uranium: 15%; Molybdenum: 12%; Niobium: 11%; Titanium: 50%; Zirconium: 10%; Aluminum: 2%.

10. A method for preparing a lightweight, structurally functional, integrated high-entropy alloy based on the U-Mo-Nb-Ti system containing uranium elements, as described in any one of claims 1-9, specifically comprising the following steps: (1) Prepare raw materials: Weigh the required alloy raw materials according to the U-Mo-Nb-Ti-Zr-Al high-entropy alloy ratio; (2) Arc melting: Under the protection of protective gas, U, Mo, Nb, Ti, Zr and Al powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly melted five times, and the samples are turned over after each melting; in order to avoid the influence of melting time and melting current difference on the microstructure and properties of the samples, each sample is kept in the melting state for 1 minute after all alloy elements are completely melted into liquid state before the current is turned off; to ensure that the surface of all samples remains bright after melting, that is, the alloy does not undergo obvious oxidation during the melting preparation process.