Aluminum-based composite material for high-density nuclear reactor based on cross-scale powder grading and preparation method of aluminum-based composite material
Aluminum-based composite materials were prepared by a cross-scale powder gradation method, which solved the problems of low density and poor mechanical properties of aluminum-based composite materials. This resulted in aluminum-based composite materials with high density and excellent shielding performance, suitable for gamma-ray and neutron shielding in nuclear reactors, and possessing good mechanical properties and integrated structural functions.
Patent Information
- Application Number
- CN202511185549.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-10-28
AI Technical Summary
Existing aluminum-based composite shielding materials for nuclear reactors have low density and poor mechanical properties, making it difficult to simultaneously meet the dual requirements of shielding performance and mechanical performance, thus limiting the safety performance and application expansion of nuclear reactors.
A multi-scale powder gradation method was adopted to combine tungsten, boron carbide and aluminum-containing materials with different particle sizes. Aluminum-based composite materials were prepared by ball milling, drying, pressing and heat preservation treatment to form a multi-level packing structure, which enhanced the material density and interfacial bonding.
A high-density aluminum-based composite material has been developed, which possesses excellent shielding performance and good mechanical properties. It integrates lightweight and high-strength structural functions and is suitable for gamma-ray and neutron shielding in nuclear reactors. The material is non-toxic and harmless, and the preparation process is simple and controllable.
Smart Images
Figure CN120843902A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation and its preparation method. Background Technology
[0002] Under the global trend of energy structure transformation towards low carbon, nuclear energy, as an energy form that combines green, clean and efficient characteristics, has become a core component of the national energy strategy layout due to its significant advantages such as near-zero carbon emissions, high energy density and stable operation. It is widely used in many key fields such as nuclear reactor power generation, aerospace propulsion, medical radiotherapy, and military equipment power, and is one of the strategic emerging energy sources that the country is currently focusing on and strongly supporting.
[0003] With the deepening application of nuclear technology and the continuous upgrading of radiation devices, the operating environment of nuclear reactors places increasingly stringent demands on the comprehensive performance of materials. In nuclear reactor systems, shielding materials, as a crucial barrier ensuring the safe operation of equipment and the health of personnel, not only need excellent neutron and gamma-ray shielding performance to effectively block nuclear radiation leakage, but also need to meet high mechanical performance indicators, such as sufficient tensile strength, good plasticity, and thermal processing properties, to adapt to the complex operating conditions of the reactor. However, most traditional aluminum-based composite shielding materials for nuclear reactors currently employ a single-scale powder addition method, resulting in problems such as low density and poor structural uniformity. This leads to poor mechanical performance, making it difficult to simultaneously meet the dual requirements of nuclear reactors for shielding and mechanical properties, severely restricting further improvements in nuclear reactor safety performance and the expanded application of nuclear technology.
[0004] Against this backdrop, developing a novel aluminum-based composite material for nuclear reactors that can balance high density, excellent shielding performance, and good mechanical properties has become crucial to overcoming current technological bottlenecks. This invention relates to a high-density aluminum-based composite material for nuclear reactors based on multi-scale powder gradation and its preparation method, specifically addressing this technological need. It aims to overcome the performance limitations of traditional materials through innovative powder gradation design and advanced powder metallurgy processes, providing more reliable material support for nuclear reactors. Summary of the Invention
[0005] The present invention aims to address the problems of low density and poor mechanical properties of existing aluminum-based composite shielding materials for nuclear reactors, and to provide a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation and its preparation method.
[0006] This invention discloses a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation, which is composed of tungsten, boron carbide, and aluminum-containing materials. The aluminum-containing materials are pure aluminum or aluminum alloys. The tungsten is composed of tungsten particles of different sizes through cross-scale gradation, and its volume fraction in the composite material is 5-20%. The boron carbide is composed of boron carbide particles of different sizes through cross-scale gradation, and its volume fraction in the composite material is 10-40%. The volume fraction of the aluminum-containing materials is 40-85%.
[0007] The present invention discloses a method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation, which is carried out according to the following steps:
[0008] 1. Weigh out 5-20% of tungsten with different particle sizes, 10-40% of boron carbide with different particle sizes, and 40-85% of aluminum-containing materials as raw materials according to volume fraction;
[0009] 2. Place the tungsten, boron carbide and aluminum-containing materials weighed in step 1 into a ball mill jar and ball mill them to obtain a mixed powder;
[0010] 3. The mixed powder obtained in step 2 is sieved and then dried to obtain a dried mixed powder;
[0011] 4. Load the dried mixed powder obtained in step 3 into a steel mold, apply a specified pressure and hold the pressure for a certain time to obtain a preform;
[0012] 5. The preform obtained in step 4 is kept at a set temperature, then a specified pressure is applied and held for a certain time, and then it is naturally cooled to room temperature and demolded to obtain the aluminum-based composite material.
[0013] The beneficial effects of this invention are:
[0014] This invention uses aluminum-containing materials as the matrix, with boron carbide and tungsten as high-hardness, high-modulus reinforcing phases. Utilizing the neutron shielding effect of boron carbide and the γ-ray and neutron shielding effect of tungsten, a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation is prepared through powder gradation and powder metallurgy processes. The comprehensive mechanical properties and heat resistance of the aluminum-based composite material prepared by this invention are far superior to polymer-based composites; the shielding efficiency per unit volume is much higher than that of cement-based composites, demonstrating strong shielding capabilities. The raw materials are tungsten, boron carbide, and aluminum-containing materials, which are non-toxic and harmless, superior to lead-containing shielding materials. Using aluminum-containing materials as the matrix reduces the material's density while ensuring its plasticity and hot working properties. The preparation process is simple, controllable, and easy for mass production. The aluminum-based composite material obtained through powder gradation has high density and a wide distribution range of volume fractions for the reinforcing and matrix materials, allowing for the acquisition of aluminum-based composite materials with multiple components to meet different performance requirements. Tungsten and aluminum-containing materials produce different interface morphologies at different temperatures; the mechanical properties can be optimized by controlling the interface morphology. This invention provides a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation and its preparation method. It can simultaneously achieve shielding against gamma rays and neutrons, has high density, good mechanical properties, low density, and the prepared material is non-toxic and harmless. The preparation process is simple and controllable, and it can realize the structural and functional integration of aluminum-based composite materials. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the interface between the reinforcement and the matrix of a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation.
[0016] Figure 2 Mechanical property data for high-density aluminum-based composite materials for nuclear reactors based on multi-scale powder gradation: where a represents the tensile curve; b represents the bending curve;
[0017] Figure 3 This is a macroscopic morphology diagram of the high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation obtained in Example 1. Detailed Implementation
[0018] Specific Implementation Method 1: This implementation method discloses a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation, which is composed of tungsten, boron carbide, and aluminum-containing materials. The aluminum-containing materials are pure aluminum or aluminum alloys. The tungsten is composed of tungsten particles of different sizes through cross-scale gradation, and its volume fraction in the composite material is 5-20%. The boron carbide is composed of boron carbide particles of different sizes through cross-scale gradation, and its volume fraction in the composite material is 10-40%. The volume fraction of the aluminum-containing materials is 40-85%.
[0019] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the aluminum alloy is a 1xxx series aluminum alloy, 2xxx series aluminum alloy, 3xxx series aluminum alloy, 4xxx series aluminum alloy, 5xxx series aluminum alloy, 6xxx series aluminum alloy, or 7xxx series aluminum alloy. Everything else is the same as in Specific Implementation Method One.
[0020] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that: the tungsten is composed of three levels of tungsten with different particle sizes. In this composite material, the volume fraction of tungsten with a particle size of 50-500 nm is 1-3%, the volume fraction of tungsten with a particle size of 1-5 μm is 3-15%, and the volume fraction of tungsten with a particle size of 10-30 μm is 1-8%, with the total volume fraction of the above-mentioned tungsten levels in the composite material being 5-20%; the boron carbide is composed of three levels of boron carbide with different particle sizes. In this composite material, the volume fraction of boron carbide with a particle size of 200-500 nm is 1-5%, the volume fraction of boron carbide with a particle size of 1-5 μm is 5-30%, and the volume fraction of boron carbide with a particle size of 10-20 μm is 5-15%, with the total volume fraction of the above-mentioned boron carbide levels in the composite material being 10-40%; the particle size of the aluminum-containing material is 1-50 μm. Everything else is the same as in Specific Implementation Method One.
[0021] This implementation employs a three-level particle size gradient design, achieving increased densification through the space-filling effect of particles of different sizes. In the tungsten powder system, 50-500nm nano-sized tungsten powder fills the gaps between 1-5μm submicron-sized tungsten powder, while 10-30μm micron-sized tungsten powder forms the skeletal structure, creating a multi-level packing system of "large particles supporting, medium particles filling, and nanoparticles filling the gaps." Boron carbide powder also follows a gradient distribution of 200-500nm, 1-5μm, and 10-20μm, forming a synergistic filling effect with the tungsten powder.
[0022] Specific Implementation Method Four: This implementation method describes a method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation, which is carried out according to the following steps:
[0023] 1. Weigh out 5-20% of tungsten with different particle sizes, 10-40% of boron carbide with different particle sizes, and 40-85% of aluminum-containing materials as raw materials according to volume fraction;
[0024] 2. Place the tungsten, boron carbide and aluminum-containing materials weighed in step 1 into a ball mill jar and ball mill them to obtain a mixed powder;
[0025] 3. The mixed powder obtained in step 2 is sieved and then dried to obtain a dried mixed powder;
[0026] 4. Load the dried mixed powder obtained in step 3 into a steel mold, apply a specified pressure and hold the pressure for a certain time to obtain a preform;
[0027] 5. The preform obtained in step 4 is kept at a set temperature, then a specified pressure is applied and held for a certain time, and then it is naturally cooled to room temperature and demolded to obtain the aluminum-based composite material.
[0028] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that: the tungsten particles of different sizes mentioned in step one are composed of tungsten with a particle size of 50-500 nm, tungsten with a particle size of 1-5 μm, and tungsten with a particle size of 10-30 μm; the boron carbide particles of different sizes are composed of boron carbide with a particle size of 200-500 nm, boron carbide with a particle size of 1-5 μm, and boron carbide with a particle size of 10-20 μm; and the aluminum-containing material has a particle size of 1-50 μm. Everything else is the same as in Specific Implementation Method Four.
[0029] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that: the total volume fraction of tungsten with a particle size of 50-500 nm is 1-3%, the total volume fraction of tungsten with a particle size of 1-5 μm is 3-15%, and the total volume fraction of tungsten with a particle size of 10-30 μm is 1-8%; the boron carbide is composed of three different particle sizes, with the total volume fraction of boron carbide with a particle size of 200-500 nm being 1-5%, the total volume fraction of boron carbide with a particle size of 1-5 μm being 5-30%, and the total volume fraction of boron carbide with a particle size of 10-20 μm being 5-15%. Everything else is the same as in Specific Implementation Method Five.
[0030] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Four in that the operating environment for step five is atmospheric. Everything else is the same as in Specific Implementation Method Four.
[0031] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Four in that the ball milling speed in step two is 100-300 r / min, and the ball milling time is 2-8 h. Everything else is the same as in Specific Implementation Method Four.
[0032] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Four in that the drying after sieving in step three involves passing the material through a 10-100 mesh sieve and then placing it in a vacuum drying oven at a temperature of 60-100℃ for 2-5 hours. Everything else is the same as in Specific Implementation Method Four.
[0033] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Four in that the loading pressure in step four is 20~100MPa and the holding time is 5~15min. Everything else is the same as in Specific Implementation Method Four.
[0034] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Method Four in that: in step five, the heat preservation temperature is 500-640℃, the heat preservation time is 2-6 hours; the loading pressure is 20-100MPa, and the pressure holding time is 10-30 minutes. Everything else is the same as in Specific Implementation Method Four.
[0035] The beneficial effects of the present invention are verified using the following embodiments:
[0036] Example 1: A method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation is carried out according to the following steps:
[0037] 1. Weigh out 15% tungsten of different particle sizes, 15% boron carbide of different particle sizes, and 70% aluminum-containing material as raw materials according to volume fractions; wherein the volume fraction of tungsten with a particle size of 50nm-500nm is 1%, the volume fraction of tungsten with a particle size of 1μm-5μm is 12%, and the volume fraction of tungsten with a particle size of 10μm-30μm is 2%; the volume fraction of boron carbide with a particle size of 200nm-500nm is 3%, the volume fraction of boron carbide with a particle size of 1μm-5μm is 10%, and the volume fraction of boron carbide with a particle size of 10μm-20μm is 2%; and the particle size of the aluminum-containing material is 10μm.
[0038] 2. Place the tungsten, boron carbide, and aluminum-containing materials weighed in step 1 into a ball mill jar and ball mill them to obtain a mixed powder; the ball mill speed is 300 r / min and the ball milling time is 6 h;
[0039] 3. The mixed powder obtained in step 2 is dried at 80℃ for 3 hours to obtain dried mixed powder;
[0040] 4. The dried mixed powder obtained in step 3 is loaded into a steel mold and held under pressure of 20MPa for 10 minutes to obtain the preform.
[0041] 5. The preform obtained in step 4 is kept at a temperature of 630℃ for 4 hours and at a pressure of 20MPa for 10 minutes. Then it is naturally cooled to room temperature and demolded to obtain the aluminum-based composite material.
[0042] In this embodiment, the aluminum matrix forms a good interfacial bond with tungsten and boron carbide (e.g. Figure 1 As shown in the interface diagram, during the sintering process, tungsten and aluminum form a diffusion layer during the heat preservation stage, improving interfacial wettability. By adjusting the heat preservation temperature and pressure parameters, the structure of the interfacial transition zone can be optimized, reducing interfacial stress concentration.
[0043] The high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation obtained from Example 1 and its preparation method were tested for mechanical properties. The tensile strength reached 150 MPa, the flexural strength was 800 MPa, the interfacial bonding was good, the strength was high, and the mechanical properties were excellent. The density was as high as 99.9% or more. The γ-ray shielding rate of the 5 mm sample was 30%, and the thermal neutron shielding rate was 99%, which has the ability to shield both γ-rays and neutrons. The structural and functional integration of lightweight, high strength and radiation protection performance of aluminum-based composite materials was realized.
Claims
1. A high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation, characterized in that... The high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation is composed of tungsten, boron carbide, and aluminum-containing materials, wherein the aluminum-containing materials are pure aluminum or aluminum alloys; the tungsten is composed of tungsten of different particle sizes through cross-scale gradation, and its volume fraction in the composite material is 5-20%; the boron carbide is composed of boron carbide of different particle sizes through cross-scale gradation, and its volume fraction in the composite material is 10-40%; the volume fraction of the aluminum-containing materials is 40-85%.
2. The high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 1, characterized in that... The aluminum alloy is a 1xxx series aluminum alloy, a 2xxx series aluminum alloy, a 3xxx series aluminum alloy, a 4xxx series aluminum alloy, a 5xxx series aluminum alloy, a 6xxx series aluminum alloy, or a 7xxx series aluminum alloy.
3. The high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 1, characterized in that... The tungsten is composed of three grades of tungsten with different particle sizes. In this composite material, the volume fraction of tungsten with a particle size of 50-500 nm is 1-3%, the volume fraction of tungsten with a particle size of 1-5 μm is 3-15%, and the volume fraction of tungsten with a particle size of 10-30 μm is 1-8%. The total volume fraction of the above grades of tungsten in the composite material is 5-20%. The boron carbide is composed of three grades of boron carbide with different particle sizes. In this composite material, the volume fraction of boron carbide with a particle size of 200-500 nm is 1-5%, the volume fraction of boron carbide with a particle size of 1-5 μm is 5-30%, and the volume fraction of boron carbide with a particle size of 10-20 μm is 5-15%. The total volume fraction of the above grades of boron carbide in the composite material is 10-40%. The particle size of the aluminum-containing material is 1-50 μm.
4. The integrated preparation method of a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation as described in claim 1, characterized in that... The preparation method of high-density aluminum-based composite materials for nuclear reactors based on cross-scale powder gradation is carried out according to the following steps:
1. Weigh out 5-20% of tungsten with different particle sizes, 10-40% of boron carbide with different particle sizes, and 40-85% of aluminum-containing materials as raw materials according to volume fraction; 2. Place the tungsten, boron carbide and aluminum-containing materials weighed in step 1 into a ball mill jar and ball mill them to obtain a mixed powder; 3. The mixed powder obtained in step 2 is sieved and then dried to obtain a dried mixed powder; 4. Load the dried mixed powder obtained in step 3 into a steel mold, apply a specified pressure and hold the pressure for a certain time to obtain a preform; 5. The preform obtained in step 4 is kept at a set temperature, then a specified pressure is applied and held for a certain time, and then it is naturally cooled to room temperature and demolded to obtain the aluminum-based composite material.
5. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 4, characterized in that... The tungsten with different particle sizes mentioned in step one is composed of tungsten with a particle size of 50-500 nm, tungsten with a particle size of 1-5 μm, and tungsten with a particle size of 10-30 μm; the boron carbide with different particle sizes is composed of boron carbide with a particle size of 200-500 nm, boron carbide with a particle size of 1-5 μm, and boron carbide with a particle size of 10-20 μm; the aluminum-containing material has a particle size of 1-50 μm.
6. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 5, characterized in that... The total volume fraction of tungsten with a particle size of 50-500 nm is 1-3%, the total volume fraction of tungsten with a particle size of 1-5 μm is 3-15%, and the total volume fraction of tungsten with a particle size of 10-30 μm is 1-8%. The boron carbide is composed of three different particle sizes. In this composite material, the total volume fraction of boron carbide with a particle size of 200-500 nm is 1-5%, the total volume fraction of boron carbide with a particle size of 1-5 μm is 5-30%, and the total volume fraction of boron carbide with a particle size of 10-20 μm is 5-15%.
7. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 4, characterized in that... In step two, the ball milling speed is 100-300 r / min, and the ball milling time is 2-8 h.
8. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 4, characterized in that... The drying process described in step three involves passing the material through a 10-100 mesh sieve and then placing it in a vacuum drying oven at a temperature of 60-100℃ for 2-5 hours.
9. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 4, characterized in that... In step four, the loading pressure is 20~100MPa and the holding time is 5~15min.
10. The method for preparing a high-density aluminum-based composite material for nuclear reactors based on cross-scale powder gradation according to claim 4, characterized in that... In step five, the heat preservation temperature is 500-640℃, and the heat preservation time is 2-6 hours; the loading pressure is 20-100MPa, and the pressure holding time is 10-30 minutes.