In-situ synthesis GdB2C2 / Al composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of neutron shielding materials, and relates to an in-situ synthesis GdB2C2 / Al composite material and a preparation method and application thereof. The invention discloses a preparation method of an in-situ synthesis GdB2C2 / Al composite material, which comprises the following steps: S1, mixing B4C powder and graphite powder to obtain mixed powder, and coating the mixed powder with aluminum foil to prepare a precast block; s2, pure aluminum is smelted, and molten metal is obtained after complete melting; heating to 900-1300 DEG C, adding an aluminum-gadolinium alloy for reaction, and then adding the precast block in S1 for reaction to obtain a reaction melt; s3, a refining agent is added into the reaction melt for stirring; and then slag on the surface of the reaction melt is removed, the reaction melt is cast into a mold to be formed, and the GdB2C2 / Al composite material is obtained. The GdB2C2 / Al composite material is generated through the in-situ reaction, so that the neutron absorption efficiency is higher.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of neutron shielding materials, and relates to an in-situ self-grown GdB2C2 / Al composite material and a preparation method and application thereof. BACKGROUND

[0002] Compared with traditional energy, nuclear energy is considered as an ideal new generation of energy due to its safety, high efficiency and environmental protection. However, with the use of nuclear fuel, a large amount of strong radioactive neutrons and gamma rays will be generated in the nuclear reaction process, and the high-density storage and subsequent treatment of spent fuel have become a key challenge in China's nuclear power industry. To solve this problem, it is a basic work to develop a high-efficiency, lightweight and excellent performance neutron shielding material for spent fuel storage. Such a material needs to have high neutron absorption efficiency and good strength and plasticity matching. The neutron absorption efficiency is mainly determined by the neutron absorption elements and their content in the material. Natural B and Gd elements are ideal neutron absorption materials due to their large neutron absorption cross section; and Al is one of the most widely used metal materials in the current industry, which has excellent strength and plasticity matching.

[0003] The traditional aluminum-based neutron shielding material is mainly B4C / Al composite material, however, the content of B4C needs to reach more than 30% to obtain good neutron absorption effect, which significantly reduces the plasticity and toughness of the composite material. If GdB2C2 particles with higher neutron absorption cross section are used to replace B4C, the comprehensive performance of the material will be improved. At present, the preparation of B4C / Al composite material mainly depends on the powder metallurgy process, but this method not only has low production efficiency, but also has high cost. Therefore, developing a technology for efficiently preparing Al-based composite material containing GdB2C2 particles is of great significance to improve the performance of neutron absorption materials. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and to provide an in-situ self-grown GdB2C2 / Al composite material and a preparation method and application thereof.

[0005] One object of the present application is achieved by the following technical scheme: A preparation method of an in-situ self-grown GdB2C2 / Al composite material, comprising the following steps: S1, mixing B4C powder and graphite powder with a mass ratio of 1: (0.36-1.02) to obtain a mixed powder, and then coating the mixed powder with aluminum foil to prepare a preform; S2, melting pure aluminum to obtain a metal melt; heating to 900-1300 DEG C and adding an aluminum-gadolinium alloy for reaction, and then adding the preform in S1 for reaction to obtain a reaction melt; S3, stirring after adding the refining agent into the reaction melt; then removing the slag on the surface of the reaction melt and casting into a mold to form a GdB2C2 / Al composite material.

[0006] Preferably, the mass ratio of the B4C powder to the graphite powder in step S1 is 1:(0.55-0.75).

[0007] Further preferably, the mass ratio of the B4C powder to the graphite powder in step S1 is 1:0.65.

[0008] Preferably, the average particle size of the B4C powder is 0.1-5 μm, and the average particle size of the graphite powder is 100-1000 nm.

[0009] Preferably, the mixed powder is coated with aluminum foil and then pressed into a preform by a hydraulic press in step S1.

[0010] Further preferably, the pressure of the hydraulic press is 5-10 MPa.

[0011] Preferably, the molar ratio of gadolinium, boron and carbon in the reaction melt in step S2 is 1:(1-3):(1-3).

[0012] Further preferably, the molar ratio of gadolinium, boron and carbon in the reaction melt is 1:2:2.

[0013] Preferably, the mass fraction of gadolinium in the reaction melt in step S2 is 0.1-4wt%.

[0014] Preferably, the pure aluminum ingot in step S2 contains 0.1-0.4wt% of impurities and the rest is Al, and the impurities include one or more of Si, Fe and Cu.

[0015] Preferably, the pure aluminum is melted at 700-800℃ in step S2.

[0016] Further preferably, the pure aluminum is melted at 730-760℃.

[0017] Preferably, the amount of the aluminum-gadolinium alloy added in step S2 is 0.1-58.0wt% of the mass of the pure aluminum.

[0018] Further preferably, the amount of the aluminum-gadolinium alloy added is 5-30.0wt% of the mass of the pure aluminum.

[0019] Preferably, the content of Gd in the aluminum-gadolinium alloy in step S2 is 1.0-30.0wt% and the rest is Al.

[0020] Further preferably, in step S2, the content of Gd in the Al-Gd alloy is 10.0-30.0wt%, and the rest is Al.

[0021] Preferably, in step S2, the amount of the preform block added is 0.1-20.0wt% of the mass of the pure aluminum.

[0022] Further preferably, the amount of the preform block added is 0.5-5.0wt% of the mass of the pure aluminum.

[0023] Preferably, in step S2, the pure aluminum is melted to obtain a metal melt; after being heated to 900-1300℃, the Al-Gd alloy is added to the metal melt to completely melt to obtain a first reaction melt, and then the preform block is added to react for 15-150min to obtain a second reaction melt.

[0024] Further preferably, in step S2, the pure aluminum is melted to obtain a metal melt; after being heated to 900-1300℃, the Al-Gd alloy is added to the metal melt to completely melt to obtain a first reaction melt, and then the preform block is placed in a graphite bell, and the graphite bell is placed below the liquid surface of the first reaction melt by 10-100mm to stir for 15-150min; during the whole reaction process, the graphite stirring rod is used to stir at a speed of 60-120r / min for 1-5min every 10-20min.

[0025] Preferably, in step S3, the amount of the refining agent added is 0.1-0.5wt% of the mass of the reaction melt.

[0026] Further preferably, the amount of the refining agent added is 0.1-0.2wt% of the mass of the reaction melt.

[0027] Preferably, in step S3, the refining agent is placed in a graphite bell, and the graphite bell is placed below the liquid surface of the reaction melt by 10-100mm to stir for 5-30min, and then it is statically placed at a temperature of 900-1300℃ for 1-30min.

[0028] Preferably, in step S3, the mold for casting is made of steel or graphite.

[0029] Preferably, in step S3, the in-situ synthesized GdB2C2 / Al composite material is an aluminum-based composite material containing GdB2C2 particles, and the mass ratio of GdB2C2 is 0.1-15wt%.

[0030] Preferably, the preparation method of the in-situ synthesized GdB2C2 / Al composite material further comprises post-processing, and the post-processing comprises: extrusion forming and / or rolling deformation. The extrusion ratio during the extrusion forming is greater than 10:1. The deformation amount during the rolling deformation is greater than 30%.

[0031] Further preferably, the in-situ self-grown GdB2C2 / Al composite material is subjected to post-treatment, and the post-treatment comprises: sequentially performing extrusion forming and rolling deformation.

[0032] More preferably, the in-situ self-grown GdB2C2 / Al composite material is subjected to extrusion forming at an extrusion ratio of (16-25):1 to obtain an extrusion-formed plate; and the extrusion-formed plate is subjected to rolling deformation with a deformation amount of 40-60%.

[0033] The second object of the application is achieved by the following technical solution: An in-situ self-grown GdB2C2 / Al composite material prepared by the above method.

[0034] Preferably, the in-situ self-grown GdB2C2 / Al composite material is an aluminum-based composite material containing GdB2C2 particles.

[0035] Further preferably, the mass percentage of the GdB2C2 is 0.1-15wt%.

[0036] Preferably, the neutron shielding performance of the GdB2C2 / Al composite material is ≥99.5%.

[0037] The third object of the application is achieved by the following technical solution: An application of the above in-situ self-grown GdB2C2 / Al composite material in neutron shielding materials and nuclear industry.

[0038] Compared with the prior art, the application has the following beneficial effects: 1. The in-situ self-grown GdB2C2 / Al composite material is prepared by the in-situ reaction of Al-Gd alloy, B4C powder and graphite powder in an aluminum melt, so that it contains the neutron-absorbing nuclide GdB2C2 with a higher neutron-absorbing cross section, thereby having a higher neutron-absorbing efficiency. 2. The GdB2C2 ceramic phase in the in-situ self-grown GdB2C2 / Al composite material has a layered structure, and as a shielding material, it can store helium between layers and capture defect aggregation caused by neutron irradiation, thereby improving the anti-irradiation capability of the shielding material. 3. The preparation method of the in-situ self-grown GdB2C2 / Al composite material is simple, the process flow is convenient, and the process reliability is high, thereby greatly improving the production efficiency and providing a feasible scheme for batch production. 4、The in-situ self-grown GdB2C2 / Al composite material preparation method of the application can seamlessly connect the extrusion and / or rolling process, realize the rapid preparation of pipe, plate and other profiles, and further optimize the structure and performance of the material. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The distribution of GdB2C2 in the Al matrix in the in-situ self-grown GdB2C2 / Al composite material of Example 1 of the application. DETAILED DESCRIPTION

[0040] The technical solutions of the application will be further described and explained with specific examples. It should be understood that the specific examples described herein are only used to help understand the application and are not used to limit the application.

[0041] If not specifically stated, the raw materials used in the examples of the application are all commonly used in the art, and the methods used in the examples are all conventional methods in the art.

[0042] In this article, the in-situ self-grown GdB2C2 / Al composite material preparation method includes the following steps: S1, mixing B4C powder and graphite powder with a mass ratio of 1:0.65 to obtain a mixed powder, and then coating the mixed powder with aluminum foil to form a preform; S2, melting pure aluminum at 700-800℃ to obtain a metal melt; heating to 900-1300℃, adding aluminum-gadolinium alloy for reaction, and then adding the preform for reaction to obtain a reaction melt; The aluminum-gadolinium alloy is added in an amount of 0.1-58.0wt% of the mass of pure aluminum; the content of Gd in the aluminum-gadolinium alloy is 10.0-30.0wt%, and the rest is Al; The preform is added in an amount of 0.1-20.0wt% of the mass of pure aluminum; The molar ratio of gadolinium, boron and carbon in the reaction melt is 1:2:2; S3, adding a refining agent to the reaction melt and stirring; then removing the slag on the surface of the reaction melt and casting into a mold to form a GdB2C2 / Al composite material.

[0043] In this article, the raw materials include: Pure aluminum: pure aluminum ingot with a purity of 99.8% from Hebei Luohong Technology Co., Ltd., and the total weight ratio of the remaining Si, Fe, Cu and other impurity elements is not more than 0.2%; Al-Gd alloy: Hebei Luohong Technology Co., Ltd., Al-30Gd, Al-15Gd, Al-10Gd, wherein Al-30Gd represents that the mass percentage of gadolinium element in the Al-Gd alloy is 30wt%; B4C powder: Zhongboron Technology (Weihai) Co., Ltd., ultra-fine powder B4C, average particle size 1 μm; Graphite powder: Qinhuangdao Yeno New Material Development Co., Ltd., 99% pure graphite powder, average particle size 500 nm; Refining agent: RJ-1 type refining agent of Shenzhen Ruibao Industry Co., Ltd.

[0044] In this paper, the mass of the aluminum foil in the pre-compacted block is small and can be ignored.

[0045] In this paper, the test method includes: yield strength, tensile strength, elongation are tested according to ASTM E8 / E8M-15a standard; neutron shielding rate is tested under the condition that the neutron energy is 0.025eV and the material thickness is 30mm.

[0046] Example 1 The preparation method of the in-situ self-grown GdB2C2 / Al composite material in this embodiment includes the following steps: S1, 4.22g of B4C powder and 2.74g of graphite powder are mixed to obtain a mixed powder, and the mixed powder is coated with an aluminum foil and then pressed into a pre-compacted block by a hydraulic press; S2, 300g of pure aluminum is melted at 740℃, and when the metal liquid is completely melted, the temperature is raised to 1200℃, 79.97g of Al-30Gd alloy is added to prepare a first reaction melt, and then the pre-compacted block is placed under the aluminum liquid surface by 50mm through the bell jar, and reacted for 60min to obtain a second reaction melt; During the whole process, every 15min, the graphite stirring rod is stirred at a speed of 60r / min for 1min; the molar ratio of gadolinium element, boron element and carbon element in the second reaction melt is 1:2:2; S3, 0.5g of refining agent is put into the graphite bell jar, then the graphite bell jar is placed under the second reaction melt liquid surface by 50mm, and stirred for 5min, and then placed at a temperature of 1200℃ for 5min, then the slag on the surface of the melt is removed using a slag removing spoon, and then cast into a steel or graphite mold to form an in-situ GdB2C2 / Al composite material.

[0047] The mass of GdB2C2 in the in-situ self-grown GdB2C2 / Al composite material of this embodiment is 8wt% of the total mass of the composite material.

[0048] According to Figure 1It can be seen that GdB2C2 particles are generated in-situ in the aluminum-based material in this embodiment, and GdB2C2 / Al composite material is successfully prepared.

[0049] The performance of the in-situ self-grown GdB2C2 / Al composite material in this embodiment is shown in Table 1.

[0050] Example 2

[0051] The preparation method of the in-situ self-grown GdB2C2 / Al composite material in this embodiment includes the following steps: S1, according to step S1 of example 1, the difference is that 1.34g of B4C powder and 0.87g of graphite powder are mixed to obtain a mixed powder, and then a preform is prepared; S2, according to step S2 of example 1, the difference is that the addition amount of Al-30Gd alloy is 25.38g; the molar ratio of gadolinium element, boron element and carbon element in the second reaction melt is 1:2:2; S3, according to step S3 of example 1.

[0052] The mass of GdB2C2 in the in-situ self-grown GdB2C2 / Al composite material of this embodiment is 3wt% of the total mass of the composite material.

[0053] The performance of the in-situ self-grown GdB2C2 / Al composite material in this embodiment is shown in Table 1.

[0054] Example 3

[0055] The preparation method of the in-situ self-grown GdB2C2 / Al composite material in this embodiment includes the following steps: S1, according to step S1 of example 1, the difference is that 1.34g of B4C powder and 0.87g of graphite powder are mixed to obtain a mixed powder, and then a preform is prepared; S2, according to step S2 of example 1, the difference is that the addition amount of Al-30Gd alloy is 25.38g; the molar ratio of gadolinium element, boron element and carbon element in the second reaction melt is 1:2:2; S3, according to step S3 of example 1.

[0056] The mass of GdB2C2 in the in-situ self-grown GdB2C2 / Al composite material of this embodiment is 3wt% of the total mass of the composite material.

[0057] The performance of the in-situ self-grown GdB2C2 / Al composite material in this embodiment is shown in Table 1.

[0058] Example 4

[0059] The preparation method of the in-situ self-grown GdB2C2 / Al composite material in this embodiment includes the following steps: S1, according to step S1 of Example 1, except that 0.44 g of B4C powder and 0.29 g of graphite powder were mixed to form a mixed powder, which was then used to form the preform; S2, according to step S2 of Example 1, except that the Al-Gd alloy was an Al-10Gd alloy, and the amount of Al-Gd alloy added was 25.27 g; the molar ratio of Gd, B and C in the second reaction melt was 1:2:2; S3, according to step S3 of Example 1.

[0060] The mass of GdB2C2 in the in-situ synthesized GdB2C2 / Al composite material of this example was 1 wt% of the total mass of the composite material.

[0061] The properties of the in-situ synthesized GdB2C2 / Al composite material of this example are shown in Table 1.

[0062] Example 5

[0063] The method for preparing the in-situ synthesized GdB2C2 / Al composite material of this example included the following steps: S1, according to step S1 of Example 1, except that 2.39 g of B4C powder and 1.56 g of graphite powder were mixed to form a mixed powder, which was then used to form the preform; S2, according to step S2 of Example 1, except that the amount of Al-30Gd alloy added was 45.33 g; the molar ratio of Gd, B and C in the second reaction melt was 1:2:2;

[0064] S3, according to step S3 of Example 1.

[0065] The mass of GdB2C2 in the in-situ synthesized GdB2C2 / Al composite material of this example was 5.7 wt% of the total mass of the composite material.

[0066] The properties of the in-situ synthesized GdB2C2 / Al composite material of this example are shown in Table 1.

[0067] Example 6

[0068] The method for preparing the in-situ synthesized GdB2C2 / Al composite material of this example included the following steps: S1, according to step S1 of Example 1; S2, 300 g of pure aluminum was melted at 740℃, when the metal liquid was completely melted, the temperature was raised to 1000℃, 79.97 g of Al-30Gd alloy was added to prepare a first reaction melt, then the preform was placed under the aluminum liquid surface by 50 mm through the bell jar, and reacted for 60 min to obtain a second reaction melt; during the whole process, a graphite stirring rod was used to stir at a speed of 60 r / min every 15 min for 1 min; S3, proceed according to step S3 of example 1.

[0069] The mass of GdB2C2 in the in-situ synthesized GdB2C2 / Al composite material of this example is 8wt% of the total mass of the composite material.

[0070] The performance of the in-situ synthesized GdB2C2 / Al composite material in this example is shown in Table 1.

[0071] Example 7

[0072] The preparation method of the in-situ synthesized GdB2C2 / Al composite material in this example includes the following steps: The in-situ synthesized GdB2C2 / Al composite material in example 1 was post-processed: extruded into a plate material by a Nantong Rugao vertical hydraulic press with an extrusion ratio of 16:1.

[0073] The performance of the in-situ synthesized GdB2C2 / Al composite material plate in this example is shown in Table 1.

[0074] Example 8

[0075] The preparation method of the in-situ synthesized GdB2C2 / Al composite material in this example includes the following steps: The in-situ synthesized GdB2C2 / Al composite material in example 1 was post-processed: extruded into a plate material by a Nantong Rugao vertical hydraulic press with an extrusion ratio of 25:1.

[0076] The performance of the in-situ synthesized GdB2C2 / Al composite material plate in this example is shown in Table 1.

[0077] Example 9

[0078] The preparation method of the in-situ synthesized GdB2C2 / Al composite material in this example includes the following steps: The in-situ synthesized GdB2C2 / Al composite material in example 1 was post-processed: extruded into a plate material by a Wuxi Guancheng double-roller mill with multi-pass hot rolling, and the final deformation of the multi-pass rolled plate material was 40%.

[0079] The performance of the in-situ synthesized GdB2C2 / Al composite material plate in this example is shown in Table 1.

[0080] Example 10

[0081] The preparation method of the in-situ synthesized GdB2C2 / Al composite material in this embodiment comprises the following steps: The in-situ synthesized GdB2C2 / Al composite material in Example 1 is post-processed: extruded into a plate by a Nantong Rugao vertical hydraulic press with an extrusion ratio of 16:1; and then rolled into a plate by a Wuxi Guancheng double-roller rolling mill through multi-pass hot rolling, and the final deformation of the multi-pass rolled plate is 40%.

[0082] The performance of the in-situ synthesized GdB2C2 / Al composite material plate in this embodiment is shown in Table 1.

[0083] Example 11

[0084] The preparation method of the in-situ synthesized GdB2C2 / Al composite material in this embodiment comprises the following steps: The in-situ synthesized GdB2C2 / Al composite material in Example 1 is post-processed: extruded into a plate by a Nantong Rugao vertical hydraulic press with an extrusion ratio of 25:1; and then rolled into a plate by a Wuxi Guancheng double-roller rolling mill through multi-pass hot rolling, and the final deformation of the multi-pass rolled plate is 40%.

[0085] The performance of the in-situ synthesized GdB2C2 / Al composite material plate in this embodiment is shown in Table 1.

[0086] Comparative Example 1 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1, 4.22 g of B4C powder and 2.74 g of graphite powder are mixed to obtain a mixed powder, and no pre-compacted block is prepared; S2, 300 g of pure aluminum is melted at 740℃, and when the metal liquid is completely melted, the temperature is raised to 1200℃, 79.97 g of Al-30Gd alloy is added to prepare a first reaction melt, and then the mixed powder in S1 is added, and reacted for 60 min to obtain a second reaction melt; during the whole process, every 15 min, the graphite stirring rod is stirred at a speed of 60 r / min for 1 min; S3, according to the step S3 of Example 1.

[0087] The performance of the aluminum-based gadolinium borocarbide composite material in this comparative example is shown in Table 1.

[0088] Comparative Example 2 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1, according to the step S1 of Example 1, the difference is that the 4.22 g of B4C powder and 5 g of graphite powder are mixed to obtain a mixed powder, and then a pre-compacted block is prepared; S2, according to the step S2 of Example 1; S3. According to step S3 of Example 1.

[0089] The properties of the aluminum-based gadolinium borocarbide composite material in this comparative example are shown in Table 1.

[0090] Comparative Example 3 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1. According to step S1 of Example 1, except that no graphite powder is added; S2. According to step S2 of Example 1; S3. According to step S3 of Example 1.

[0091] The properties of the aluminum-based gadolinium borocarbide composite material in this comparative example are shown in Table 1.

[0092] Comparative Example 4 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1. According to step S1 of Example 1; S2. According to step S2 of Example 1, except that the amount of Al-50Gd alloy added is 200g; the molar ratio of gadolinium element, boron element, and carbon element in the second reaction melt is 2.1:1:1; S3. According to step S3 of Example 1.

[0093] The properties of the aluminum-based gadolinium borocarbide composite material in this comparative example are shown in Table 1.

[0094] Comparative Example 5 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1. According to step S1 of Example 1; S2. 300g of pure aluminum is melted at 740℃, and after the metal liquid is completely melted, without temperature increase, 79.97g of Al-30Gd alloy is added to form a first reaction melt, and then the preform is placed under the aluminum liquid surface by 50mm through the bell jar, and fully reacts for 60min to obtain a second reaction melt; during the whole process, every 15min, a graphite stirring rod is used to stir at a speed of 60r / min for 1min; S3. According to step S3 of Example 1.

[0095] The properties of the aluminum-based gadolinium borocarbide composite material in this comparative example are shown in Table 1.

[0096] Comparative Example 6 The preparation method of the aluminum-based composite material in this comparative example comprises the following steps: S1. According to step S1 of Example 1; S2, 300 g of pure aluminum was melted at 740 ℃, after the molten metal was completely melted, the temperature was increased to 1500 ℃, 79.97 g of Al-30Gd alloy was added to prepare a first reaction melt, then the preform was placed into the aluminum liquid surface 50 mm below through the bell jar, and reacted for 60 min to obtain a second reaction melt; during the whole process, a graphite stirring rod was used to stir at a speed of 60 r / min every 15 min for 1 min; S3, proceed according to step S3 of example 1.

[0097] The properties of the aluminum-based gadolinium borocarbide composite material in the present comparative example are shown in Table 1.

[0098]

[0099] According to the above table, the GdB2C2 / Al composite material prepared by in-situ reaction according to the present application has excellent mechanical properties and neutron shielding performance; and further heat deformation post-processing can further improve the performance of the composite material.

[0100] In comparative example 1, since the B4C powder and C powder are not wrapped with aluminum foil and pre-pressed into a preform, most of the low-density powder floats on the surface of the aluminum liquid, which is difficult to fully react with the dissolved Gd element in the aluminum liquid, and also causes serious burning loss, resulting in a significant decrease in the mechanical properties and neutron shielding performance of the composite material; in comparative example 2, the addition amount of graphite powder is too high, and the excess free carbon reacts with aluminum to form needle-shaped brittle phase Al4C3, inducing stress concentration and micro-cracks, holes, thereby weakening the mechanical properties and neutron shielding performance of the composite material; in comparative example 3, no graphite powder is added, and the carbon source in the system is insufficient, resulting in a significant decrease in the generation amount of GdB2C2 phase and a decrease in neutron shielding performance; at the same time, the excess boron element exists in the form of free B4C particles and brittle AlB2 phase, which destroys the uniformity of the structure and further deteriorates the material performance; in comparative example 4, after increasing the Gd content, the excess Gd in the system forms brittle intermetallic compounds (Al2Gd, Al3Gd) with aluminum, which weakens the interface bonding and the toughness of the matrix, while the neutron absorption performance is limitedly improved; in comparative example 5, the melt temperature is increased to 1500 ℃, which causes the gadolinium element to change from the dissolved state to the free state and causes serious burning loss, and the carbon activity is significantly increased, which easily generates brittle Al4C3 and AlB2 phase, thereby inhibiting the generation of GdB2C2, and causing a significant decrease in the mechanical properties and neutron shielding performance of the composite material.

[0101] In comparative example 6, the melt temperature is not increased, which causes insufficient reaction conditions of the aluminum liquid, the dissolution of Gd and the reaction of Gd with B4C and C are limited, the GdB2C2 phase is not completely formed and the content is low, the residual powder is removed with the slag, and finally the mechanical properties and neutron shielding performance of the composite material are significantly reduced.

[0102] In summary, the appropriate in-situ reaction temperature, the precise control of the Gd, B, C element ratio and the reasonable preform design are the keys to realize the high performance of the GdB2C2 / Al composite material.

[0103] Aspects, embodiments, features of the present application are to be considered illustrative only and not restrictive in all aspects. The scope of the present application is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art, and the embodiments are not intended to limit the scope of the application, which is defined by the claims.

[0104] In the preparation method of the present application, the order of each step is not limited to the listed order, and for those skilled in the art, the order of each step can be changed without creative labor, which is within the protection scope of the present application. In addition, two or more steps or actions can be performed simultaneously.

[0105] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the embodiments of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. Here, all embodiments do not need and cannot be fully exemplified. Any obvious changes or variations derived from the spirit of the present application still belong to the protection scope of the present application, and any additional limitation is contrary to the spirit of the present application.

Claims

1. A method for preparing an in-situ self-generated GdB2C2 / Al composite material, characterized in that, The preparation method includes the following steps: S1. Mix B4C powder and graphite powder in a mass ratio of 1:(0.36~1.02) to obtain a mixed powder, and then wrap the mixed powder with aluminum foil to form a preform. S2. Pure aluminum is smelted and completely melted to obtain a molten metal; the temperature is raised to 900~1300℃ and aluminum-gadolinium alloy is added to react, and then the preformed block in S1 is added to react to obtain a reactive melt; S3. Add the refining agent to the reaction melt and stir; then remove the slag from the surface of the reaction melt and cast it into a mold to obtain the GdB2C2 / Al composite material.

2. The method for preparing in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, In step S2, the molar ratio of gadolinium, boron and carbon in the reaction melt is 1:(1~3):(1~3).

3. The method for preparing in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, In step S2, pure aluminum is smelted and completely melted to obtain a molten metal. After heating to 900~1300℃, aluminum-gadolinium alloy is added to the molten metal until it is completely melted to obtain a first reaction melt. Then, a preform is added and reacted for 15~150 minutes to obtain a second reaction melt.

4. The method for preparing the in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, In step S2, the amount of aluminum-gadolinium alloy added is 0.1 to 58.0 wt% of the mass of pure aluminum.

5. The method for preparing in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, In step S2, the amount of preform added is 0.1 to 20.0 wt% of the mass of pure aluminum.

6. The method for preparing the in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, In step S3, the amount of refining agent added is 0.1~0.5 wt% of the mass of the reaction melt.

7. The method for preparing in-situ self-generated GdB2C2 / Al composite material according to claim 1, characterized in that, The preparation method of the in-situ self-generated GdB2C2 / Al composite material further includes post-processing, which includes: extrusion molding and / or rolling deformation; The extrusion ratio during extrusion molding is greater than 10:1; The deformation during rolling is greater than 30%.

8. An in-situ self-generated GdB2C2 / Al composite material, characterized in that, It is prepared by the method for preparing in-situ self-generated GdB2C2 / Al composite material as described in any one of claims 1 to 7; The in-situ self-generated GdB2C2 / Al composite material is an aluminum-based composite material containing GdB2C2 particles.

9. The in-situ self-generated GdB2C2 / Al composite material according to claim 8, characterized in that, The mass percentage of GdB2C2 in the in-situ self-generated GdB2C2 / Al composite material is 0.1~15wt%.

10. The application of an in-situ self-generated GdB2C2 / Al composite material in neutron shielding materials and the nuclear industry, characterized in that, The in-situ self-generated GdB2C2 / Al composite material is prepared by the preparation method of the in-situ self-generated GdB2C2 / Al composite material as described in any one of claims 1 to 7, or is the in-situ self-generated GdB2C2 / Al composite material as described in any one of claims 8 to 9.

Images