A high-temperature-resistant HfB2 reinforced yttrium-based composite material for nuclear shielding, a preparation method thereof and application thereof

Abstract

This invention discloses a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material, its preparation method, and its applications. The yttrium-based alloy material of this invention has the following composition by mass percentage: Hf: 0.5–25.0%, B: 0.1–3.0%, satisfying 8.0 ≤ Hf / B ≤ 8.5, with the remainder being yttrium and unavoidable impurities. After batching and special melting processes, the material is cast and formed, then subjected to hot forging or hot pressing, hot rolling, cold rolling, annealing, and hydrogenation processes to finally obtain a high-temperature yttrium-based alloy composite material plate integrating neutron moderation absorption and gamma-ray shielding. This invention effectively reduces the grain size of the yttrium-based alloy through alloying, improving its resistance to hydrogen-induced cracking, hot workability, and neutron and gamma-ray shielding capabilities, which is beneficial for realizing lightweight shielding designs for micro-miniature nuclear reactors.

Description

Technical Field

[0001] This invention relates to a yttrium-based alloy material, and more particularly to a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding, which is applied in the field of nuclear functional special alloy materials technology. Background Technology

[0002] The continuous development of miniature mobile nuclear propulsion systems has placed higher demands on the lightweight and high-temperature resistance of shielding systems. The performance of shielding materials directly affects the performance and safety of nuclear reactor power supplies. YH2, as a moderator, can withstand temperatures above 1100℃ and maintain a high hydrogen density within its temperature tolerance range. Currently, the preparation of YH2 faces difficulties, mainly due to the abnormally large grain size of yttrium alloys and their poor resistance to high-temperature oxidation, leading to hydrogen-induced cracking and oxidation problems in preparation and use. Furthermore, YH2 metal hydride moderator materials only have shielding capabilities against fast neutrons, limiting their engineering applications. Due to increasingly higher shielding environment temperatures and the need to ensure mobility, miniature mobile nuclear reactors urgently require the development of new high-temperature resistant, highly efficient yttrium-based alloy composite materials that integrate neutron moderation and absorption with gamma-ray shielding. Summary of the Invention

[0003] To address the problems of existing materials and technologies, the present invention aims to overcome their shortcomings and provide a novel high-temperature resistant, high-efficiency yttrium-based alloy composite material integrating neutron moderation and gamma-ray shielding. This invention produces a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material with fine grain structure, high temperature resistance, and radiation resistance. It can both moderate fast neutrons and absorb thermal neutrons, and also shield gamma rays. The manufacturing process is simple, it is resistant to hydrogen-induced cracking, and it is easy to process. This invention can be used as an integrated composite shielding body for neutron moderation and gamma-ray shielding in advanced reactors such as micro-mobile nuclear reactors.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following inventive concept:

[0005] Natural boron has an average thermal neutron absorption cross section of 750 barn, exhibiting excellent thermal neutron absorption capabilities. Hafnium, a heavy metal with a high atomic number (Z=72), has an average thermal neutron absorption cross section of 115 barn and a relative atomic mass of 178.49, providing excellent thermal neutron and gamma-ray shielding capabilities. Furthermore, boron and hafnium form the high-melting-point compound HfB2. During the melting and solidification process of yttrium-based alloys, HfB2 plays a role in refining the grain size, thus enabling the refined yttrium-based alloy to maintain high strength and toughness. It is also less prone to cracking during hot working and high-temperature hydrogenation processes, exhibiting excellent hot working performance and high-temperature resistance. This invention, through extensive experimentation, has discovered that by adding appropriate proportions of boron and hafnium to yttrium-based alloys and employing a special vacuum melting process, yttrium-based alloys with high-temperature resistance, strong integrated neutron moderation and absorption shielding capabilities, and good strength and toughness can be prepared. The high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material of this invention has the advantages of high overall shielding efficiency, good strength and toughness, and high temperature resistance.

[0006] Based on the above inventive concept, the present invention adopts the following technical solution:

[0007] A high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material has the following composition by mass percentage: 0.5% ≤ Hf ≤ 25.0%, 0.1% ≤ B ≤ 3.0%, and satisfies 8.0 ≤ Hf / B ≤ 8.5, with the remainder being yttrium and unavoidable impurities.

[0008] Preferably, the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding of the present invention further contains any one or more elements of Dy and Gd, with a mass percentage of Dy≤15.0% and Gd≤10.0%.

[0009] More preferably, the high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material of the present invention is composed of the following mass percentages: Hf: 0.5-25.0%, B: 0.1-3.0%, Dy≤15.0%, Gd≤10.0%, and the remainder being yttrium and unavoidable impurities.

[0010] More preferably, the components of the present invention are composed of the following mass percentages: Hf: 5.0-15.0%, B: 0.6-1.8%, Dy≤8.0%, Gd≤5.0%, and the remainder being yttrium and unavoidable impurities.

[0011] Preferably, the grain size of the alloy material in the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding described in this invention is 30–100 μm. More preferably, the grain size of the alloy material in the HfB2-reinforced yttrium-based composite material is 30–80 μm.

[0012] A method for preparing the high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material of the present invention includes the following steps:

[0013] a. A special vacuum melting process is adopted. When the raw materials are batched, the raw material composition is made up according to the following mass percentage: Hf: 0.5~25.0%, B: 0.1~3.0%, and satisfying 8.0≤Hf / B≤8.5. The remaining raw material components are yttrium and unavoidable impurities. All the raw materials weighed after batching are smelted to obtain alloy melt, and then cast into alloy ingot.

[0014] b. The alloy ingot prepared in step a is subjected to hot forging or hot pressing, hot rolling, cold rolling, annealing and hydrogenation processes in sequence to finally obtain HfB2 reinforced yttrium-based composite material plates for high-temperature nuclear shielding.

[0015] Preferably, in step a, the composition of the high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate is as follows by mass percentage: Hf: 0.5-25.0%, B: 0.1-3.0%, Dy≤15.0%, Gd≤10.0%, and the remaining components are yttrium and unavoidable impurities.

[0016] More preferably, in step a, the composition of the high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate is as follows by mass percentage: Hf: 5.0-15.0%, B: 0.6-1.8%, Dy≤8.0%, Gd≤5.0%, and the remaining components are yttrium and unavoidable impurities.

[0017] Preferably, in step a, a special vacuum melting process is used, in which the prepared raw materials are placed in a special vacuum furnace and evacuated to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas. Then, the temperature is increased to 2000℃±10℃ at a heating rate of not less than 3℃ / min, and held at that temperature for at least 10min to obtain an alloy melt, which is then cast into an alloy ingot.

[0018] Preferably, in step b, the alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling; wherein, the hot pressing temperature is controlled to be not lower than 800°C, the hot rolling temperature is not lower than 850°C, and the rolling is repeated at least 3 times; then, cold rolling is performed at least 3 times; then, argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, followed by cooling to room temperature, and finally, HfB2 reinforced yttrium-based composite material plate for high temperature nuclear shielding is obtained.

[0019] The present invention relates to an application of HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding, which is used as a high-temperature neutron and gamma-ray composite shielding material in high-temperature environments above 800°C, while simultaneously slowing down fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0020] Preferably, the high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material of the present invention is used as a neutron and gamma-ray composite shielding material for nuclear reactors.

[0021] More preferably, the nuclear reactor is a mobile micro nuclear reactor.

[0022] The elemental design principle of the HfB2-reinforced yttrium-based composite material of this invention is as follows:

[0023] Y has a low density and a strong hydrogen binding ability. Yttrium hydride, obtained after hydrogenation, has a high decomposition temperature and excellent ability to slow down fast neutrons at high temperatures.

[0024] Hf has an atomic number of 72 and a relative atomic mass of 178.49. The density of metallic hafnium is about 13.3 g / cm3, and it has a good gamma-ray shielding ability. According to the mass percentage of the components, the amount of Hf used in this invention is 0.5% ≤ Hf ≤ 25.0%, and preferably 5.0% to 15.0%.

[0025] The average thermal neutron absorption cross section of element boron reaches 750 barn, exhibiting excellent thermal neutron absorption capacity. Simultaneously, boron and hafnium form a high-melting-point compound HfB2, which plays a role in refining grains during the solidification process of yttrium-based alloys. Calculated according to the component mass percentage, the amount of boron used in this invention is 0.1% ≤ B ≤ 3.0%, preferably 0.6% to 1.8%.

[0026] Dy element can improve the thermal neutron and gamma-ray shielding ability of yttrium-based alloys. According to the component mass percentage, the preferred amount of Dy in this invention is: Dy≤15.0%, and more preferably Dy≤8%.

[0027] Gd can improve the thermal neutron and gamma-ray shielding ability of yttrium-based alloys. According to the mass percentage of the components, the amount of Gd used in this invention is: Gd≤10.0%, preferably ≤5%.

[0028] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:

[0029] 1. Compared with currently used metal hydride moderator materials such as LiH, ZrH2 and TiH2, the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding of this invention has a higher decomposition temperature and can be used in high-temperature environments above 800℃. It is a high-temperature resistant neutron and gamma-ray composite shielding material.

[0030] 2. The HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding of this invention, after undergoing heat treatment processes such as hot rolling or hot pressing and annealing within its composition range, has a fine grain structure, high strength and toughness, and can resist hydrogen-induced cracking, which is conducive to the successful implementation of the hydrogenation process.

[0031] 3. The high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material of this invention contains Hf, B, Dy, or Gd elements. B, Dy, and Gd elements all have large thermal neutron absorption cross sections and can absorb thermal neutrons. They are the best candidate materials to replace the current neutron shielding materials such as LiH, ZrH2, and TiH2. At the same time, Hf is a heavy element that can effectively shield gamma rays. It is a high-efficiency composite shielding material that integrates neutron moderation absorption and gamma ray shielding.

[0032] 4. The high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material of the present invention has good high-temperature performance, good toughness and plasticity, crack resistance, radiation resistance, and simple production process; the high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material of the present invention can be used as an integrated composite shielding body for neutron and gamma rays in advanced nuclear reactors such as micro-mobile reactors. Attached Figure Description

[0033] Figure 1 This is a metallographic photograph of the HfB2-reinforced yttrium-based composite material according to Embodiment 1 of the present invention. Detailed implementation method:

[0034] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of the present invention are described in detail below:

[0035] Example 1:

[0036] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 0.5%, B: 0.1%, and the remainder being Y and unavoidable impurities.

[0037] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0038] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0039] Hf 0.5%

[0040] B 0.1%

[0041] Y balance

[0042] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0043] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0044] Experimental test analysis:

[0045] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 100 μm. The microstructure of the HfB2 reinforced yttrium-based composite alloy in this embodiment mainly consists of a matrix Y and precipitates. After hot rolling and cold rolling, the precipitates are distributed in the matrix, such as... Figure 1 As shown in the figure, the HfB2-reinforced yttrium-based composite material of this embodiment can relatively alleviate hydrogen absorption cracking during the hydrogenation process, while also providing good shielding against neutrons and gamma rays. It is a highly efficient high-temperature resistant neutron moderation and absorption, and gamma-ray shielding integrated composite shielding yttrium-based alloy material, making it a promising candidate to replace current small reactor neutron shielding materials such as LiH, ZrH2, and TiH2. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding against gamma rays.

[0046] Example 2:

[0047] This embodiment is basically the same as Embodiment 1, except that:

[0048] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 2%, B: 0.2%, and the remainder being Y and unavoidable impurities.

[0049] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0050] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0051] Hf 2%

[0052] B 0.2%

[0053] Y balance

[0054] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0055] b. In step b, the alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein, the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then, cold rolling is performed 3 times; then, argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0056] Experimental test analysis:

[0057] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 70–80 μm, which can effectively prevent hydrogen absorption cracking during the hydrogenation process. It also provides good shielding against neutrons and gamma rays, making it a promising candidate to replace current small reactor neutron shielding materials such as LiH, ZrH2, and TiH2. It is a highly efficient, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption as well as gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding against gamma rays.

[0058] Example 3:

[0059] This embodiment is basically the same as the above embodiments, except that:

[0060] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 5%, B: 0.6%, and the remainder being Y and unavoidable impurities.

[0061] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0062] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0063] Hf 5%

[0064] B 0.6%

[0065] Y balance

[0066] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0067] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0068] Experimental test analysis:

[0069] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 40-50 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption as well as gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0070] Example 4:

[0071] This embodiment is basically the same as the above embodiments, except that:

[0072] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 7%, B: 0.9%, and the remainder being Y and unavoidable impurities.

[0073] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0074] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0075] Hf 7.5%

[0076] B 0.9%

[0077] Y balance

[0078] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0079] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0080] Experimental test analysis:

[0081] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 30-40 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption, and gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0082] Example 5:

[0083] This embodiment is basically the same as the above embodiments, except that:

[0084] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 10%, B: 1.2%, and the remainder being Y and unavoidable impurities.

[0085] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0086] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0087] Hf 10%

[0088] B 1.2%

[0089] Y balance

[0090] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0091] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0092] Experimental test analysis:

[0093] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 30-40 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption, and gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0094] Example 6:

[0095] This embodiment is basically the same as the above embodiments, except that:

[0096] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 15%, B: 1.8%, and the remainder being Y and unavoidable impurities.

[0097] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0098] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0099] Hf 15%

[0100] B 1.8%

[0101] Y balance

[0102] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0103] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0104] Experimental test analysis:

[0105] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 30-40 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption, and gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0106] Example 7:

[0107] This embodiment is basically the same as the above embodiments, except that:

[0108] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 20%, B: 2.5%, and the remainder being Y and unavoidable impurities.

[0109] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0110] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0111] Hf 20%

[0112] B 2.5%

[0113] Y balance

[0114] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0115] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0116] Experimental test analysis:

[0117] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 30-40 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption, and gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0118] Example 8:

[0119] This embodiment is basically the same as the above embodiments, except that:

[0120] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 25%, B: 3%, and the remainder being Y and unavoidable impurities.

[0121] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0122] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0123] Hf 25%

[0124] B 3%

[0125] Y balance

[0126] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0127] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0128] Experimental test analysis:

[0129] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 30-40 μm and a fine grain structure, which can avoid hydrogen absorption cracking during the hydrogenation process. It can also shield neutrons and gamma rays, making it the best candidate material to replace current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption, and gamma ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0130] Example 9:

[0131] This embodiment is basically the same as Embodiment 3, except that:

[0132] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is provided, with the following material composition by mass percentage: Hf: 5%, B: 0.6%, Dy: 8%, and the remainder being Y and unavoidable impurities.

[0133] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0134] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0135]

[0136] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0137] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0138] Experimental test analysis:

[0139] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 40-50 μm and a fine grain structure, which effectively avoids hydrogen absorption cracking during the hydrogenation process. The addition of Dy has no significant impact on the alloy structure, but it can improve the material's ability to absorb thermal neutrons. This makes the material more efficient at shielding neutrons and is the best candidate material to replace the current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption as well as gamma-ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0140] Example 10:

[0141] This embodiment is basically the same as Embodiment 3, except that:

[0142] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 5%, B: 0.6%, Dy: 15%, with the remainder being Y and unavoidable impurities.

[0143] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0144] a. A special vacuum melting process is adopted, and the raw material components are prepared according to the following mass percentages:

[0145]

[0146] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0147] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0148] Experimental test analysis:

[0149] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 40-50 μm and a fine grain structure, which effectively avoids hydrogen absorption cracking during the hydrogenation process. The addition of Dy has no significant impact on the alloy structure, but it can improve the material's ability to absorb thermal neutrons. This makes the material more efficient at shielding neutrons and is the best candidate material to replace the current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, integrated composite shielding yttrium-based alloy material for neutron moderation and absorption as well as gamma-ray shielding. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0150] Example 11:

[0151] This embodiment is basically the same as Embodiment 3, except that:

[0152] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 5%, B: 0.6%, Gd: 5%, with the remainder being Y and unavoidable impurities.

[0153] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0154] a. A special vacuum melting process is adopted, and the raw material composition is determined according to the following mass percentage (%):

[0155]

[0156] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0157] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0158] Experimental test analysis:

[0159] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 40–50 μm and a fine grain structure, which effectively avoids hydrogen absorption cracking during the hydrogenation process. The addition of Gd has no significant impact on the alloy structure, while improving the material's ability to absorb thermal neutrons. This makes the material more efficient at shielding neutrons and the best candidate material to replace the current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, neutron-moderating, absorption-resistant, and gamma-ray-shielding integrated composite shielding yttrium-based alloy material. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0160] Example 12:

[0161] This embodiment is basically the same as Embodiment 3, except that:

[0162] In this embodiment, a high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material is composed of the following material components in the following mass percentages: Hf: 5%, B: 0.6%, Gd: 5%, with the remainder being Y and unavoidable impurities.

[0163] In this embodiment, a method for preparing a high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding includes the following steps:

[0164] a. A special vacuum melting process is adopted, and the raw material composition is determined according to the following mass percentage (%):

[0165]

[0166] Place the prepared raw materials into a special vacuum furnace and evacuate to a vacuum level of 3×10⁻⁶. -3 The temperature is increased to above Pa, and then high-purity argon gas is introduced as a protective gas; then the temperature is increased to 2000℃ at a heating rate of 3℃ / min, and held at that temperature for 10min to obtain the alloy melt.

[0167] b. The alloy ingot obtained by casting the alloy melt prepared in step a is subjected to hot pressing and hot rolling treatment; wherein the hot pressing temperature is controlled at 800℃ and the hot rolling temperature is 850℃, and the rolling is repeated 3 times; then cold rolling is performed 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature to finally obtain high temperature resistant nuclear shielding HfB2 reinforced yttrium-based composite material plate.

[0168] Experimental test analysis:

[0169] Experimental tests showed that the alloy material prepared in this embodiment has a grain size of 40–50 μm and a fine grain structure, which effectively avoids hydrogen absorption cracking during the hydrogenation process. The addition of Gd has no significant impact on the alloy structure, while improving the material's ability to absorb thermal neutrons. This makes the material more efficient at shielding neutrons and the best candidate material to replace the current LiH, ZrH2, and TiH2 series materials used for neutron shielding in small reactors. It is a high-efficiency, high-temperature resistant, neutron-moderating, absorption-resistant, and gamma-ray-shielding integrated composite shielding yttrium-based alloy material. In this embodiment, the HfB2-reinforced yttrium-based composite material is used as a high-temperature resistant neutron and gamma-ray composite shielding material at temperatures above 800°C, simultaneously moderating fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

[0170] In summary, the high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material described in the above embodiments has the following main components in the following mass percentages (%): Hf: 0.5–25.0, B: 0.1–3.0, with the remaining components being yttrium and unavoidable impurities. As a further technical solution of the present invention, the high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material has the following composition: Hf: 5.0–15.0, B: 0.6–1.8, Dy≤8.0, Gd≤5.0, with the remaining components being yttrium and unavoidable impurities. When the Hf / B mass ratio of the raw materials is not within the range of 8.0 ≤ Hf / B ≤ 8.5, the prepared HfB2-reinforced yttrium-based composite alloy has relatively coarse grains. For example, in Examples 1 and 2, the corresponding Hf / B ratios are 5.0 and 10, respectively. The mismatch in the Hf and B content ratios limits the grain refinement effect, resulting in grain sizes of 100 μm and 70-80 μm, which are relatively coarse. In contrast, in Examples 3 to 12 of this invention, the Hf / B ratio is 8.0 ≤ Hf / B ≤ 8.34, resulting in grain sizes of 30-50 μm, significant grain refinement, and more prominent structural strength and toughness. Examples 3 to 12 of this invention obtain an alloy melt through batching and a special vacuum melting process; after casting, it undergoes hot forging or hot pressing, hot rolling, annealing, and hydrogenation processes to finally obtain a high-temperature resistant HfB2-reinforced yttrium-based composite material plate for nuclear shielding. The HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding described in the above embodiments of the present invention has advantages such as fine grains, good strength and toughness, resistance to hydrogen absorption cracking, and high shielding efficiency.

[0171] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent substitutions. As long as they meet the purpose of the invention and do not deviate from the technical principle and inventive concept of the high-temperature nuclear shielding HfB2-reinforced yttrium-based composite material and its preparation method, they shall fall within the protection scope of the present invention.

Claims

1. A high-temperature resistant HfB2-reinforced yttrium-based composite material for nuclear shielding, characterized in that, The material composition is as follows by mass percentage: 0.5%≤Hf≤25.0%, 0.1%≤B≤3.0%, and the Hf / B mass ratio satisfies 8.0≤Hf / B≤8.

5. The remaining components are yttrium and unavoidable impurities.

2. The high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material according to claim 1, characterized in that, Its material composition also contains any one or both of the elements Dy and Gd, with the following mass percentages: Dy≤15.0%, Gd≤10.0%.

3. The HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding according to claim 1 or 2, characterized in that, Its material composition is as follows by mass percentage: Hf: 0.5~25.0%, B: 0.1~3.0%, Dy≤15.0%, Gd≤10.0%, and the remaining components are yttrium and unavoidable impurities.

4. The high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material according to claim 3, characterized in that, Its material composition is as follows by mass percentage: Hf: 5.0~15.0%, B: 0.6~1.8%, Dy≤8.0%, Gd≤5.0%, and the remaining components are yttrium and unavoidable impurities.

5. The high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material according to claim 1, characterized in that: The grain size of its alloy material is 30–100 μm.

6. A method for preparing the high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material as described in claim 1, characterized in that: Includes the following steps: a. A special vacuum melting process is adopted. When the raw materials are batched, the raw material composition is made up according to the following mass percentage: Hf: 0.5~25.0%, B: 0.1~3.0%, and satisfying 8.0≤Hf / B≤8.

5. The remaining raw material components are yttrium and unavoidable impurities. All the raw materials weighed after batching are smelted to obtain alloy melt, and then cast into alloy ingot. b. The alloy ingot prepared in step a is subjected to hot forging or hot pressing, hot rolling, cold rolling, annealing and hydrogenation processes in sequence to finally obtain HfB2-reinforced yttrium-based composite material plates for high-temperature nuclear shielding.

7. The method for preparing the high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material according to claim 6, characterized in that: In step a, the high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate is composed of the following mass percentages: Hf: 0.5~25.0%, B: 0.1~3.0%, Dy≤15.0%, Gd≤10.0%, and the remaining components are yttrium and unavoidable impurities.

8. The application of the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding as described in claim 1, characterized in that, It is used as a high-temperature resistant composite shielding material for neutrons and gamma rays in high-temperature environments above 800℃, while simultaneously slowing down fast neutrons, absorbing thermal neutrons, and shielding gamma rays.

9. The application of the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding according to claim 8, characterized in that: The high-temperature resistant nuclear shielding HfB2-reinforced yttrium-based composite material is used as a neutron and gamma-ray composite shielding material for nuclear reactors.

10. The application of the HfB2-reinforced yttrium-based composite material for high-temperature nuclear shielding according to claim 9, characterized in that: The nuclear reactor is a mobile micro nuclear reactor.

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