TaB2 reinforced yttrium-based composite material for high-temperature-resistant nuclear shielding as well as preparation method and application of TaB2 reinforced yttrium-based composite material

Abstract

The invention discloses a high-temperature-resistant TaB2 reinforced yttrium-based composite material for nuclear shielding as well as a preparation method and application of the TaB2 reinforced yttrium-based composite material. The yttrium-based alloy material comprises the following components in percentage by mass: 0.5-25.0% of Ta, 0.1-3.0% of B, and the balance of yttrium and inevitable impurities, wherein Ta / B is more than or equal to 8.0 and less than or equal to 8.5. The high-temperature-resistant yttrium-based alloy composite material plate integrating neutron moderation absorption and gamma-ray shielding is finally prepared through the processes of burdening, melting through a special process, casting molding, hot forging or hot pressing, hot rolling, cold rolling, annealing and hydrogenation, and finally the high-temperature-resistant yttrium-based alloy composite material plate integrating neutron moderation absorption and gamma-ray shielding is prepared. According to the invention, the grain size of the yttrium-based alloy is effectively reduced through alloying, the hydrogen induced cracking resistance, hot workability and neutron and gamma ray shielding capability of the yttrium-based alloy are improved, and the shielding lightweight design of a micro nuclear reactor can be realized.

Description

Technical Field

[0001] The invention relates to a yttrium-based alloy material for nuclear shielding, in particular to a TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding, which is applied in the technical field of special alloy materials for nuclear energy. Background Art

[0002] Small nuclear reactors are easy to install and deploy, with stable and reliable energy supply. They can be used in a variety of high-demand application scenarios such as space power supply, deep-sea exploration energy, and land vehicle power supply. As an indispensable component in a nuclear reactor, the performance of the shielding system directly affects the performance of the nuclear reactor power supply. With the continuous development of micro-mobile reactors, the output power increases, and the shielding outlet temperature increases day by day, requiring the shielding material to be able to withstand higher temperatures. At present, the maximum temperature tolerance of metal hydrides used for neutron shielding in unmanned space reactors abroad is below 800°C, such as LiH (unstable, decomposes at about 600°C), ZrH2 (decomposes at about 800°C), and TiH2 (decomposes at about 800°C). Studies have shown that the hydrogen decomposition temperature of YH2 is as high as 1000°C and above, and it is more stable, but at present, due to the abnormally coarse grains of existing yttrium alloys, hydrogen embrittlement cracking is prone to occur during the hydrogenation process. In addition, the existing yttrium hydride mainly shields fast neutrons, but has weak shielding capabilities for thermal neutrons and gamma rays, and its engineering applications are limited. As the shielding environment temperature of small mobile reactors becomes higher and higher, there is an urgent need to develop new composite shielding materials with low density, high comprehensive shielding efficiency, high temperature resistance, and integrated neutron moderation absorption and gamma-ray shielding. Summary of the invention

[0003] In order to solve the problems existing in the existing materials and technologies, the purpose of the present invention is to overcome the shortcomings of the existing materials and technologies, and to provide a composite shielding yttrium-based alloy material that is resistant to high temperatures, has concentrated neutron moderation absorption, and integrates gamma-ray shielding, and to prepare a composite shielding yttrium-based alloy material that is resistant to high temperatures, has concentrated neutron moderation absorption, and integrates gamma-ray shielding. The TaB2-reinforced yttrium-based composite material for high-temperature nuclear shielding of the present invention has fine grains, is resistant to hydrogen-induced cracking, is resistant to high temperatures, can shield fast neutrons, absorb thermal neutrons, and shield gamma rays, and has a simple production process and is easy to process. The present invention can be used as a composite shielding body for neutrons and gamma rays in advanced reactors such as small nuclear reactors.

[0004] In order to achieve the above-mentioned invention object, the present invention adopts the following inventive concept:

[0005] The average thermal neutron absorption cross section of natural boron is 750 barn, which has excellent thermal neutron absorption capacity. The density of tantalum is 16.7 g / cm 3The atomic number of Ta element is 73, and the relative atomic weight is 180.95. It has excellent gamma-ray shielding ability and certain thermal neutron absorption ability, with an absorption cross section of 21.3 barn. Boron and tantalum can form a high melting point compound TaB2, which plays a role in refining grains during alloy melting and solidification, so that the yttrium-based alloy with refined structure is not easy to crack during hot processing and high-temperature hydrogenation process, and has excellent hot processing performance and high temperature resistance. The present invention has found through a large number of experiments that by adding B and Ta elements in a suitable proportion to the yttrium-based alloy, a yttrium-based alloy with high temperature resistance, neutron slowing and absorption integrated composite shielding ability, and good toughness can be prepared through a special vacuum melting process. The TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding in the present invention has the advantages of high comprehensive shielding efficiency, low density, good toughness, and high temperature resistance.

[0006] According to the above inventive concept, the present invention adopts the following technical solution:

[0007] A TaB2 reinforced yttrium-based composite material for high-temperature nuclear shielding, wherein the components are composed according to the following mass percentages: 0.5%≤Ta≤25.0%, 0.1%≤B≤3.0%, and 8.0≤Ta / B≤8.5 is satisfied, and the remaining components are yttrium and unavoidable impurities.

[0008] Preferably, the components of the TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention have the following mass percentage composition: 2.0%≤Ta≤15.0%, 0.3%≤B≤1.8%, and satisfy 8.0≤Ta / B≤8.5, and the remaining components are yttrium and unavoidable impurities.

[0009] Preferably, the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention is characterized in that the grain size of the alloy material is 20 to 80 μm.

[0010] Further preferably, the grain size of the alloy material of the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention is 20 to 50 μm.

[0011] A method for preparing a TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding according to the present invention comprises the following steps:

[0012] a. A special vacuum melting process is adopted. When the raw materials are batched, the main raw material components are batched according to the following mass percentage composition: Ta: 0.5-25.0%, B: 0.1-3.0%, and 8.0≤Ta / B≤8.5 is satisfied; wherein, TaY master alloy is used as the raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as the raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. All the raw materials weighed after batching are subjected to special smelting to obtain an alloy melt, and cast into an alloy ingot; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0013] 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 a TaB2-reinforced yttrium-based composite material sheet for high-temperature resistant nuclear shielding.

[0014] Preferably, in step a, the components of the prepared TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding are composed according to the following mass percentages: 2.0%≤Ta≤15.0%, 0.3%≤B≤1.8%, and satisfying 8.0≤Ta / B≤8.5, and the remaining components are yttrium and unavoidable impurities.

[0015] Preferably, in step a, a special vacuum melting process is used to place the prepared raw materials in a special vacuum furnace and evacuate to 3×10 -3 Pa or above, and then introduce high-purity argon as a protective gas; then heat up and heat to 2000℃±10℃ at a heating rate of not less than 3℃ / min, and keep the temperature for at least 10min to obtain an alloy melt, which is then cast to obtain an alloy ingot.

[0016] Preferably, in the step b, the alloy ingot obtained by casting the alloy melt prepared in the step a is subjected to hot pressing and hot rolling treatments; wherein, the hot pressing processing temperature is controlled to be not less than 800°C, the hot rolling temperature is not less than 850°C, the rolling is repeated at least 3 times, and then cold rolling is performed at least 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature, and finally TaB2 reinforced yttrium-based composite material plate for high temperature resistant nuclear shielding is obtained.

[0017] An application of the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding according to the present invention. In a high-temperature environment of 600-1000°C, the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding according to the present invention is used as a high-temperature neutron moderation absorption and gamma-ray composite shielding material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0018] Preferably, the TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is used as a material for preparing a neutron and gamma-ray composite shielding body in a nuclear reactor.

[0019] Further preferably, the nuclear reactor is a small mobile reactor.

[0020] The action and mechanism of the main elements of the present invention are as follows:

[0021] Y has a smaller density and stronger hydrogen binding ability. The yttrium hydride obtained after hydrogenation process has a higher decomposition temperature and has excellent ability to slow down fast neutrons at high temperature.

[0022] The atomic number of Ta is 72, its relative atomic mass is as high as 178.49, and the density of metallic tantalum is about 16.7 g / cm 3 , has good gamma ray shielding ability, and has certain thermal neutron absorption ability, with an absorption cross section of 21.3 barn. The preferred mass percentage of Ta used in the present invention is 2.0-15.0%.

[0023] The average thermal neutron absorption cross section of element B is 750 barn, and it has excellent thermal neutron absorption capability. Boron and hafnium form a high melting point compound TaB2, which plays a role in grain refinement during the solidification of yttrium-based alloys. The preferred mass percentage of B used in the present invention is 0.3-1.8%.

[0024] The TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding described in the present invention can be used as a yttrium-based alloy material for high-efficiency neutron moderation absorption and gamma-ray shielding integrated composite shielding, and can be used as an integrated composite shielding material for preparing neutron moderation absorption and gamma-ray shielding in advanced reactors such as micro-mobile nuclear reactors.

[0025] Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

[0026] 1. Compared with the currently used metal hydride moderator materials such as LiH, ZrH2 and TiH2, the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention has a higher decomposition temperature and can be used in a high-temperature environment above 800°C. It is a high-temperature resistant neutron and gamma-ray composite shielding material.

[0027] 2. The TaB2 reinforced yttrium-based composite material for high-temperature nuclear shielding of the present invention has a fine grain structure after being subjected to heat treatment processes such as hot rolling or hot pressing, annealing, etc. within its composition range. It has high strength and toughness, can resist hydrogen-induced cracking, and is conducive to the successful implementation of the hydrogenation process.

[0028] 3. The TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention contains B and Ta elements. The B element has a large thermal neutron absorption cross-section and can absorb thermal neutrons. The Ta element can effectively shield gamma rays. It is the best candidate to replace the current series of shielding materials such as metal hydrides for neutron shielding in the future. It is a highly efficient composite shielding material integrating neutron moderation absorption and gamma ray shielding.

[0029] 4. The TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention has good high-temperature performance, resistance to hydrogen absorption cracking, high comprehensive shielding efficiency, and simple production process; the TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention can be used as an integrated composite shielding body for neutron radiation and gamma-ray radiation shielding in advanced nuclear reactors such as small mobile reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a metallographic structure photograph of the TaB2 reinforced yttrium-based composite material according to Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The above scheme is further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0032] Embodiment 1:

[0033] In this embodiment, a TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 0.5%, B: 0.1%, and the remaining components are yttrium and unavoidable impurities.

[0034] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0035] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0036] Ta 0.5%

[0037] B 0.1%

[0038] Y margin

[0039] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0040] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0041] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0042] Experimental test analysis:

[0043] After experimental testing, the test results show that the grain size of the alloy material prepared in this embodiment is 80μm. The alloy structure of the TaB2-reinforced yttrium-based composite material in this embodiment is mainly composed of matrix Y and precipitates. After hot rolling and cold rolling, the precipitates are distributed in the matrix, such as Figure 1 As shown. The TaB2 reinforced yttrium-based composite material of this embodiment can relatively alleviate hydrogen absorption cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is a better candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0044] Embodiment 2:

[0045] This embodiment is basically the same as the first embodiment, except that:

[0046] In this embodiment, a TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 2.0%, B: 0.3%, and the remaining components are yttrium and unavoidable impurities.

[0047] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0048] a. Using a special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage (%):

[0049] Ta 2.0%

[0050] B 0.3%

[0051] Y margin

[0052] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0053] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0054] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0055] Experimental test analysis:

[0056] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 50μm, which can better avoid hydrogen absorption cracking in the hydrogenation process, and can better shield neutrons and gamma rays. It is a better candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 used for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0057] Embodiment three:

[0058] This embodiment is basically the same as the above embodiment, with the following features:

[0059] In this embodiment, a TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 5.0%, B: 0.6%, and the remaining components are yttrium and unavoidable impurities.

[0060] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0061] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0062] Ta 5.0%

[0063] B 0.6%

[0064] Y margin

[0065] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0066] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0067] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0068] Experimental test analysis:

[0069] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current LiH, ZrH2 and TiH2 series materials used for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0070] Embodiment 4:

[0071] This embodiment is basically the same as the above embodiment, with the following features:

[0072] In this embodiment, a TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 7.0%, B: 0.9%, and the remaining components are yttrium and unavoidable impurities.

[0073] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0074] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0075] Ta 7.5%

[0076] B 0.9%

[0077] Y margin

[0078] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0079] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0080] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0081] Experimental test analysis:

[0082] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current LiH, ZrH2 and TiH2 series materials used for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0083] Embodiment five:

[0084] This embodiment is basically the same as the above embodiment, with the following features:

[0085] In this embodiment, a TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 10.0%, B: 1.2%, and the remaining components are yttrium and unavoidable impurities.

[0086] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0087] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0088] Ta 10.0%

[0089] B 1.2%

[0090] Y margin

[0091] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0092] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0093] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0094] Experimental test analysis:

[0095] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 20 to 30 μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0096] Embodiment six:

[0097] This embodiment is basically the same as the above embodiment, with the following features:

[0098] In this embodiment, a TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 15.0%, B: 1.8%, and the remaining components are yttrium and unavoidable impurities.

[0099] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0100] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0101] Ta 15.0%

[0102] B 1.8%

[0103] Y margin

[0104] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0105] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0106] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0107] Experimental test analysis:

[0108] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 20 to 30 μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0109] Embodiment seven:

[0110] This embodiment is basically the same as the above embodiment, with the following features:

[0111] In this embodiment, a TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 20.0%, B: 2.5%, and the remaining components are yttrium and unavoidable impurities.

[0112] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0113] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0114] Ta 20.0%

[0115] B 2.5%

[0116] Y margin

[0117] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0118] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0119] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0120] Experimental test analysis:

[0121] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 20 to 30 μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0122] Embodiment eight:

[0123] This embodiment is basically the same as the above embodiment, with the following features:

[0124] In this embodiment, a TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its components are composed according to the following mass percentages: Ta: 25.0%, B: 3.0%, and the remaining components are yttrium and unavoidable impurities.

[0125] In this embodiment, a method for preparing a TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding comprises the following steps:

[0126] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0127] 25%

[0128] B 3.0%

[0129] Y margin

[0130] The weighed raw materials are mixed after batching, wherein TaY master alloy is used as raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is added in the form of boron powder as raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities. The prepared raw materials are placed in a special vacuum furnace and evacuated to 3×10 - 3 Pa or above, and then introduce high-purity argon as protective gas;

[0131] Then, the temperature is raised to 2000°C±10°C at a heating rate of 3°C / min, and the temperature is kept for 10 minutes, and vacuum smelting is performed to obtain an alloy melt; since the melting point of tantalum is as high as 3000°C, Ta is added in the form of TaY master alloy to lower the melting point of the tantalum raw material;

[0132] b. hot pressing and hot rolling the alloy ingot obtained by casting the alloy melt prepared in step a; wherein the hot pressing temperature is controlled at 800°C and the hot rolling temperature is controlled at 850°C, the rolling is repeated 3 times, and 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 TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0133] Experimental test analysis:

[0134] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 20 to 30 μm and a fine grain structure, which can avoid hydrogen absorption and cracking during the hydrogenation process, and can shield neutrons and gamma rays. It is the best candidate material to replace the current series of materials such as LiH, ZrH2 and TiH2 for neutron shielding in small reactors in the future. It can be used in high temperature environments above 800°C. It is a high-efficiency, high-temperature resistant neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

[0135] In summary, the above-mentioned embodiments 1 to 8 of the TaB2-reinforced yttrium-based composite material for high temperature nuclear shielding have the following components in mass percentage: Ta: 0.5-25.0%, B: 0.1-3.0%, and the remaining raw material components are yttrium and inevitable impurities. As a further technical solution of the present invention, the TaB2-reinforced yttrium-based composite material for high temperature nuclear shielding: Ta: 2.0-15.0%, B: 0.3-1.8%, and the remaining components are yttrium and inevitable impurities. When the Ta / B mass ratio of the raw material is not within the range of 8.0≤Ta / B≤8.5, the prepared TaB2-reinforced yttrium-based composite material alloy material has relatively coarse grains, such as in embodiments 1 and 2, the corresponding Ta / B is 5.0 and 6.67, the mass fraction of Ta contained therein is too high, the amount of B is insufficient, and the content of Ta and B does not match, so that the grain refinement effect is limited, and the grain size is 80μm and 50μm, which is relatively coarse. In the third to eighth embodiments of the present invention, 8.0≤Ta / B≤8.34, the grain size is 20-30μm, the grain refinement is obvious, and the structural strength and toughness are more prominent. In the third to eighth embodiments of the present invention, the alloy melt is obtained through the batching and special vacuum melting process; after casting, hot forging or hot pressing, hot rolling, annealing and hydrogenation processes, a TaB2-reinforced yttrium-based composite material sheet for high-temperature resistant nuclear shielding is finally obtained. The TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the above embodiments of the present invention has the advantages of fine grains, good toughness, resistance to hydrogen absorption cracking, and high shielding efficiency.

[0136] The embodiments of the present invention are 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 according to the spirit and principle of the technical solution of the present invention should be equivalent replacement methods. As long as they meet the purpose of the present invention and do not deviate from the technical principles and inventive concepts of the TaB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding and its preparation method of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding, characterized in that: The components thereof are composed according to the following mass percentages: 0.5%≤Ta≤25.0%, 0.1%≤B≤3.0%, and satisfying 8.0≤Ta / B≤8.5, and the remaining components are yttrium and unavoidable impurities.

2. The TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1, characterized in that: The components thereof are composed according to the following mass percentages: 2.0%≤Ta≤15.0%, 0.3%≤B≤1.8%, and satisfying 8.0≤Ta / B≤8.5, and the remaining components are yttrium and unavoidable impurities.

3. The TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1, characterized in that: The grain size of the alloy material is 20 to 80 μm.

4. The TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 2, characterized in that: The grain size of the alloy material is 20 to 50 μm.

5. A method for preparing the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1, characterized in that: The steps include: a. A special vacuum melting process is adopted. When the raw materials are batched, the main raw material components are batched according to the following mass percentage composition: Ta: 0.5-25.0%, B: 0.1-3.0%, and 8.0≤Ta / B≤8.5 is satisfied; wherein, TaY master alloy is used as the raw material for addition, and the mass percentage content of Y element in TaY master alloy is 15%; boron element is boron powder added as the raw material, and the remaining raw material components are part of yttrium-based alloy or pure yttrium and inevitable impurities, and all the raw materials weighed after batching are subjected to special smelting to obtain an alloy melt, and cast to obtain an 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 a TaB2-reinforced yttrium-based composite material sheet for high-temperature resistant nuclear shielding.

6. The method for preparing the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 5, characterized in that: In step a, the components of the prepared TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding are composed according to the following mass percentages: 2.0%≤Ta≤15.0%, 0.3%≤B≤1.8%, and satisfying 8.0≤Ta / B≤8.5, and the remaining components are yttrium and unavoidable impurities.

7. The method for preparing the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 5, characterized in that: In the step b, the alloy ingot obtained by casting the alloy melt prepared in the step a is subjected to hot pressing and hot rolling treatments; wherein, the hot pressing processing temperature is controlled to be not less than 800°C, and the hot rolling temperature is controlled to be not less than 850°C, and the rolling is repeated at least 3 times, and then cold rolling is performed at least 3 times; then argon protective atmosphere annealing heat treatment and hydrogenation process heat treatment are performed, and then cooled to room temperature, and finally a TaB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding is obtained.

8. An application of the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1, characterized in that: In a high temperature environment of 600-1000°C, the TaB2-reinforced yttrium-based composite material for high temperature resistant nuclear shielding is used as a high temperature resistant neutron moderation absorption and gamma ray composite shielding material, and is also used as a composite shielding material for shielding fast neutrons, thermal neutrons and gamma rays.

9. The use of the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 8, characterized in that: The TaB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is used as a material for preparing a neutron and gamma-ray composite shielding body in a nuclear reactor.

10. The use of the TaB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 9, characterized in that: The nuclear reactor is a small mobile reactor.

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