High-temperature-resistant HfB2 reinforced yttrium-based composite material for nuclear shielding as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature-resistant HfB2 reinforced yttrium-based composite material for nuclear shielding as well as a preparation method and application thereof, the yttrium-based alloy material comprises the following components in percentage by mass: 0.5-25.0% of Hf, 0.1-3.0% of B, and the balance of yttrium and inevitable impurities, and Hf / B is greater 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, in particular to a HfB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding, which is applied to the technical field of special alloy materials with nuclear functions. Background Art

[0002] The continuous development of small and micro mobile nuclear propulsion systems has put forward higher requirements for 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 high temperatures above 1100°C and maintain a high hydrogen density within the tolerable temperature range. At present, the preparation of YH2 faces difficulties. The main reason is that the yttrium alloy grains are abnormally coarse and have poor resistance to high-temperature oxidation. There are problems of hydrogen-induced cracking and oxidation in the preparation and use. In addition, the YH2 metal hydride moderator material only has shielding capabilities for fast neutrons, and its engineering application is subject to certain restrictions. Due to the increasing shielding environment temperature of small and micro mobile nuclear reactors and the need to ensure mobility, there is an urgent need to develop high-temperature resistant, efficient neutron moderation absorption and gamma-ray shielding integrated yttrium-based alloy composite new materials. 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, provide a high-temperature resistant, efficient neutron moderation absorption and gamma-ray shielding integrated yttrium-based alloy composite new material, and prepare a high-temperature resistant, efficient neutron moderation absorption and gamma-ray shielding integrated yttrium-based alloy composite new material. The HfB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention has a fine grain structure, high temperature resistance, and radiation resistance. It can moderate fast neutrons, absorb thermal neutrons, and shield gamma rays. The production process is simple, resistant to hydrogen-induced cracking, and easy to process. The present invention can be used as a neutron moderation absorption and gamma-ray shielding integrated composite shielding body in advanced reactors such as micro-sized mobile 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 reaches 750 barn, which has excellent thermal neutron absorption capacity. Hafnium is a heavy metal with a high atomic number (Z=72), and the average thermal neutron absorption cross section of hafnium reaches 115 barn. The relative atomic mass of Hf reaches 178.49, which has good thermal neutron and gamma ray shielding ability. At the same time, boron and hafnium form a high melting point compound HfB2. HfB2 plays a role in refining grains during the smelting and solidification process of yttrium-based alloys, so that the yttrium-based alloy with refined structure can maintain high strength and toughness, and is not prone to cracking during hot processing and high-temperature hydrogenation processes, and has excellent hot processing performance, high temperature resistance and other characteristics. The present invention has found through a large number of experiments that by adding appropriate proportions of boron and hafnium elements to yttrium-based alloys, a yttrium-based alloy with high temperature resistance, strong neutron moderation and absorption integrated composite shielding ability, and good strength and toughness can be prepared through a special vacuum melting process. The HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding in the present invention has the advantages of high comprehensive shielding efficiency, good strength and toughness, high temperature resistance, etc.

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

[0007] A HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding, wherein the material components are composed according to the following mass percentages: 0.5%≤Hf≤25.0%, 0.1%≤B≤3.0%, and 8.0≤Hf / B≤8.5 is satisfied, and the remaining components are yttrium and unavoidable impurities.

[0008] Preferably, the HfB2 reinforced yttrium-based composite material component for high temperature resistant nuclear shielding of the present invention further contains any one element or any several elements of Dy and Gd, and the mass percentages thereof are: Dy≤15.0%, Gd≤10.0%.

[0009] Further preferably, the components of the HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention are composed according to 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.

[0010] More preferably, the composition of the present invention is composed according to the following mass percentages: 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.

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

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

[0013] a. A special vacuum melting process is used. When the raw materials are batched, the raw material components are batched according to the following mass percentage composition: Hf: 0.5-25.0%, B: 0.1-3.0%, and 8.0≤Hf / B≤8.5 is satisfied. The remaining raw material components are yttrium and unavoidable impurities. All the raw materials weighed after batching are smelted to obtain an alloy melt, and cast to obtain an 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 a HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0015] Preferably, in step a, the components of the prepared high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate are composed according to 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.

[0016] Further preferably, in the step a, the components of the prepared high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate are composed according to the following mass percentages: 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 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 at a heating rate of not less than 3°C / min to 2000°C±10°C, and keep the temperature for at least 10 minutes to obtain an alloy melt, which is then cast to obtain an alloy ingot.

[0018] 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, 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, and then cooled to room temperature, and finally HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding is obtained.

[0019] An application of the HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding described in the present invention is used as a high-temperature resistant neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, while slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

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

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

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

[0023] 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.

[0024] The atomic number of Hf is 72, and its relative atomic mass is as high as 178.49. The density of metal hafnium is about 13.3 g / cm3, and it has good gamma-ray shielding ability. Calculated according to the mass percentage of the components, the amount of Hf used in the present invention is 0.5%≤Hf≤25.0%, and the preferred amount of Hf is 5.0% to 15.0%.

[0025] The average thermal neutron absorption cross section of element B reaches 750 barn, and it has excellent thermal neutron absorption capacity. At the same time, boron and hafnium form a high melting point compound HfB2. During the solidification process of the yttrium-based alloy, HfB2 plays a role in refining the grains. Calculated according to the mass percentage of the components, the amount of B in the present invention is 0.1%≤B≤3.0%, and the preferred amount of B is 0.6%-1.8%.

[0026] The Dy element can improve the thermal neutron and gamma ray shielding capabilities of the yttrium-based alloy. Calculated according to the mass percentage of the components, the preferred amount of Dy in the present invention is: Dy≤15.0%, preferably Dy≤8%.

[0027] The Gd element can improve the thermal neutron and gamma ray shielding capabilities of the yttrium-based alloy. Calculated according to the mass percentage of the components, the amount of Gd used in the present invention is: Gd≤10.0%, preferably the amount of Gd≤5%.

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

[0029] 1. Compared with the currently used metal hydride moderator materials such as LiH, ZrH2 and TiH2, the HfB2 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.

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

[0031] 3. The HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present 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 LiH, ZrH2 and TiH2 series for neutron shielding in the future. At the same time, Hf is a heavy element that can effectively shield gamma rays. It is a highly efficient composite shielding material that integrates neutron moderation absorption and gamma ray shielding.

[0032] 4. The HfB2-reinforced yttrium-based composite material for high-temperature resistant nuclear shielding of the present invention has good high-temperature performance, good toughness and plasticity, crack resistance, radiation resistance, and simple production process; the HfB2-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 and gamma-ray shielding in advanced nuclear reactors such as micro-mobile reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a metallographic structure photograph of the HfB2 reinforced yttrium-based composite material according to Example 1 of the present invention. DETAILED DESCRIPTION

[0034] 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:

[0035] Embodiment 1:

[0036] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 0.5%, B: 0.1%, and the remaining components are Y and unavoidable impurities.

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

[0038] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0039] Hf 0.5%

[0040] B 0.1%

[0041] Y margin

[0042] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0043] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0044] Experimental test analysis:

[0045] After experimental testing, the test results show that the grain size of the alloy material prepared in this embodiment is 100 μm. The HfB2-reinforced yttrium-based composite material alloy structure 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 HfB2-reinforced yttrium-based composite material of this embodiment can relatively alleviate hydrogen absorption cracking during the hydrogenation process, and can better shield neutrons and gamma rays. It is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material, and 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. The HfB2-reinforced yttrium-based composite material of this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0046] Embodiment 2:

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

[0048] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 2%, B: 0.2%, and the remaining components are Y and unavoidable impurities.

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

[0050] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0051] Hf 2%

[0052] B 0.2%

[0053] Y margin

[0054] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0055] b. 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 800°C, the hot rolling temperature is controlled to be 850°C, 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, and finally HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding is obtained.

[0056] Experimental test analysis:

[0057] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 70 to 80 μm, which can better avoid hydrogen absorption cracking during 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 for neutron shielding in small reactors in the future. It is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material of this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0058] Embodiment three:

[0059] This embodiment is basically the same as the above embodiment, with the following features:

[0060] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 5%, B: 0.6%, and the remaining components are Y and unavoidable impurities.

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

[0062] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0063] Hf 5%

[0064] B 0.6%

[0065] Y margin

[0066] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 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 40 to 50 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0070] Embodiment 4:

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

[0072] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 7%, B: 0.9%, and the remaining components are Y and unavoidable impurities.

[0073] In this embodiment, a method for preparing a HfB2-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] Hf 7.5%

[0076] B 0.9%

[0077] Y margin

[0078] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0079] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0080] Experimental test analysis:

[0081] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30 to 40 μm and a fine grain structure, which can avoid hydrogen absorption 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0082] Embodiment five:

[0083] This embodiment is basically the same as the above embodiment, with the following features:

[0084] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 10%, B: 1.2%, and the remaining components are Y and unavoidable impurities.

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

[0086] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0087] Hf 10%

[0088] B 1.2%

[0089] Y margin

[0090] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0091] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0092] Experimental test analysis:

[0093] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30 to 40 μm and a fine grain structure, which can avoid hydrogen absorption 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0094] Embodiment six:

[0095] This embodiment is basically the same as the above embodiment, with the following features:

[0096] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 15%, B: 1.8%, and the remaining components are Y and unavoidable impurities.

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

[0098] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0099] Hf 15%

[0100] B 1.8%

[0101] Y margin

[0102] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0103] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0104] Experimental test analysis:

[0105] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30 to 40 μm and a fine grain structure, which can avoid hydrogen absorption 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0106] Embodiment seven:

[0107] This embodiment is basically the same as the above embodiment, with the following features:

[0108] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are composed according to the following mass percentages: Hf: 20%, B: 2.5%, and the remaining components are Y and unavoidable impurities.

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

[0110] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0111] Hf 20%

[0112] B 2.5%

[0113] Y margin

[0114] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0115] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0116] Experimental test analysis:

[0117] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30 to 40 μm and a fine grain structure, which can avoid hydrogen absorption 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0118] Embodiment eight:

[0119] This embodiment is basically the same as the above embodiment, with the following features:

[0120] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are composed according to the following mass percentages: Hf: 25%, B: 3%, and the remaining components are Y and unavoidable impurities.

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

[0122] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0123] Hf 25%

[0124] B 3%

[0125] Y margin

[0126] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0127] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0128] Experimental test analysis:

[0129] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 30 to 40 μm and a fine grain structure, which can avoid hydrogen absorption 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 is a high-efficiency high-temperature neutron moderation absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, and it can slow down fast neutrons, absorb thermal neutrons and shield gamma rays at the same time.

[0130] Embodiment nine:

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

[0132] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are as follows according to the following mass percentages: Hf: 5%, B: 0.6%, Dy: 8%, and the remaining components are Y and unavoidable impurities.

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

[0134] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0135]

[0136] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0137] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0138] Experimental test analysis:

[0139] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 40 to 50 μm and a fine grain structure, which can effectively avoid hydrogen absorption cracking during the hydrogenation process. The addition of Dy has no significant effect on the alloy structure, and at the same time can improve the material's absorption capacity for thermal neutrons, so that the material in this embodiment can shield neutrons more efficiently. 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 is a high-efficiency high-temperature neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, while slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

[0140] Embodiment ten:

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

[0142] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are composed according to the following mass percentages: Hf: 5%, B: 0.6%, Dy: 15%, and the remaining components are Y and unavoidable impurities.

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

[0144] a. Using special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage composition:

[0145]

[0146] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0147] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0148] Experimental test analysis:

[0149] After experimental testing, the test results show that the alloy material prepared in this embodiment has a grain size of 40 to 50 μm and a fine grain structure, which can effectively avoid hydrogen absorption cracking during the hydrogenation process. The addition of Dy has no significant effect on the alloy structure, and at the same time can improve the material's absorption capacity for thermal neutrons, so that the material in this embodiment can shield neutrons more efficiently. 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 is a high-efficiency high-temperature neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, while slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

[0150] Embodiment eleven:

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

[0152] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are composed according to the following mass percentages: Hf: 5%, B: 0.6%, Gd: 5%, and the remaining components are Y and unavoidable impurities.

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

[0154] a. Using a special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage (%):

[0155]

[0156] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0157] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0158] Experimental test analysis:

[0159] After experimental testing, the test results show that the grain size of the alloy material prepared in this embodiment is 40-50μm, the grain structure is fine, and hydrogen absorption cracking can be effectively avoided during the hydrogenation process. The addition of Gd has no significant effect on the alloy structure, and at the same time, it can improve the material's absorption capacity for thermal neutrons, so that the material in this example can shield neutrons more efficiently. 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 is a high-efficiency high-temperature neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, while slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

[0160] Embodiment 12:

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

[0162] In this embodiment, a HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding is provided, and its material components are composed according to the following mass percentages: Hf: 5%, B: 0.6%, Gd: 5%, and the remaining components are Y and unavoidable impurities.

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

[0164] a. Using a special vacuum melting process, when mixing raw materials, the raw material components used are mixed according to the following mass percentage (%):

[0165]

[0166] The prepared raw materials were placed in a special vacuum furnace and vacuumed to 3×10 -3 Pa or more, and then introduce high-purity argon as a protective gas; then heat up to 2000°C at a heating rate of 3°C / min, and keep the temperature for 10 minutes to obtain an alloy melt;

[0167] 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 to be 800°C, the hot rolling temperature is 850°C, 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, finally obtaining HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

[0168] Experimental test analysis:

[0169] After experimental testing, the test results show that the grain size of the alloy material prepared in this embodiment is 40-50μm, the grain structure is fine, and hydrogen absorption cracking can be effectively avoided during the hydrogenation process. The addition of Gd has no significant effect on the alloy structure, and at the same time, it can improve the material's absorption capacity for thermal neutrons, so that the material in this example can shield neutrons more efficiently. 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 is a high-efficiency high-temperature neutron slowing absorption and gamma-ray shielding integrated composite shielding yttrium-based alloy material. The HfB2-reinforced yttrium-based composite material in this embodiment is used as a high-temperature neutron and gamma-ray composite shielding material in a high-temperature environment above 800°C, while slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

[0170] In summary, the HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding in the above embodiment has the following main components in mass percentage (%): Hf: 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 HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding: Hf: 5.0-15.0, B: 0.6-1.8, Dy≤8.0, Gd≤5.0, and the remaining components are yttrium and inevitable impurities. When the Hf / B mass ratio of the raw material is not within the range of 8.0≤Hf / B≤8.5, the prepared HfB2-reinforced yttrium-based composite alloy material has relatively coarse grains. For example, in Example 1 and Example 2, the corresponding Hf / B is 5.0 and 10, the content ratio of Hf and B does not match, the grain refinement effect is limited, and the grain size is 100μm and 70-80μm, which is relatively coarse. In Example 3 to Example 12 of the present invention, 8.0≤Hf / B≤8.34, the grain size is 30-50μm, the grain refinement is obvious, and the structural toughness is more prominent. In Example 3 to Example 12 of the present invention, an alloy melt is obtained by batching and a special vacuum melting process; after casting, hot forging or hot pressing, hot rolling, annealing and hydrogenation processes, a HfB2-reinforced yttrium-based composite material sheet for high-temperature nuclear shielding is finally obtained. The HfB2 reinforced yttrium-based composite material for high-temperature resistant nuclear shielding in the above-mentioned embodiment of the present invention has the advantages of fine grains, good toughness, resistance to hydrogen absorption cracking, and high shielding efficiency.

[0171] 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 HfB2-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 HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding, characterized in that: The material composition is as follows according to the following mass percentages: 0.5%≤Hf≤25.0%, 0.1%≤B≤3.0%, and 8.0≤Hf / B≤8.5 is satisfied, and the remaining components are yttrium and unavoidable impurities.

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

3. The HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1 or 2, characterized in that: The material components are composed according to 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 inevitable impurities.

4. The HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 3, characterized in that: The material composition is as follows in 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 inevitable impurities.

5. The HfB2 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 30 to 100 μm.

6. A method for preparing the HfB2 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 used. When the raw materials are batched, the raw material components are batched according to the following mass percentage composition: Hf: 0.5-25.0%, B: 0.1-3.0%, and 8.0≤Hf / B≤8.5 is satisfied. The remaining raw material components are yttrium and unavoidable impurities. All the raw materials weighed after batching are smelted 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 HfB2 reinforced yttrium-based composite material plate for high-temperature resistant nuclear shielding.

7. The method for preparing the HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 6, characterized in that: In step a, the components of the prepared high-temperature resistant neutron moderation and absorption integrated composite shielding yttrium-based alloy material plate are composed according to 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. An application of the HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 1, characterized in that: In high temperature environments above 800°C, it is used as a high-temperature neutron and gamma-ray resistant composite shielding material, slowing down fast neutrons, absorbing thermal neutrons and shielding gamma rays.

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

10. The use of the HfB2 reinforced yttrium-based composite material for high temperature resistant nuclear shielding according to claim 7, characterized in that: The nuclear reactor is a mobile micro nuclear reactor.

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