CN115810434A - Tungsten mesh toughened aluminum-based composite nuclear shielding material and preparation method thereof - Google Patents

Abstract

The present invention relates to the technical field of nuclear radiation protection composite materials, more specifically a tungsten mesh toughened aluminum-based composite nuclear shielding material and a preparation method thereof. Step 1: select and process tungsten mesh; Turbid liquid; step 3: tungsten mesh is cut and stacked, neutron absorber suspension is brushed on the surface of each layer of tungsten mesh, and after drying, tungsten mesh prefabrication is formed; step 4: tungsten mesh prefabrication is pressed into the steel mold ;Step 5: Preheat the tungsten mesh preform and melt the aluminum metal; Step 6: Cast the molten aluminum metal on the preheated tungsten mesh preform; Step 7: Pressurize the molten aluminum metal to impregnate the preheated tungsten mesh Prefabricated body; Step 8: Maintain pressure and cool naturally to make a tungsten mesh toughened aluminum matrix composite nuclear shielding material; the composite material uses boron and/or gadolinium-containing particles as neutron absorbing components, and tungsten mesh as gamma The ray-absorbing component is based on aluminum metal, which has comprehensive shielding ability and good mechanical properties.

Description

Tungsten mesh toughened aluminum-based composite nuclear shielding material and preparation method thereof

technical field

The invention relates to the technical field of nuclear radiation protection composite materials, in particular to a tungsten mesh toughened aluminum-based composite nuclear shielding material and a preparation method thereof.

Background technique

Nuclear shielding materials play a vital role in the safe application of nuclear energy. For nuclear reactor power plants that require lightweight and miniaturization, nuclear shielding materials need to have better mechanical properties and lower specific gravity.

In order to meet the needs of structural and functional integration of nuclear shielding materials, a lot of research has been carried out at home and abroad, and a series of high-efficiency metal-based and polymer-based comprehensive shielding composite materials such as shielding concrete, boron steel, and lead-boron polyethylene have been designed and developed.

For example, patent CN105014075 has prepared a lead-aluminum-boron composite shielding material with excellent shielding performance and mechanical properties, but its preparation process is relatively complicated, and the shielding concrete is easily corroded by the environment, which affects the absorption effect of the material on shielding particles.

For example, patent CN110774512A has prepared a tungsten-boron polyethylene shielding body with high tungsten content, which has high nuclear radiation shielding efficiency, but this material contains polymer, and its heat resistance is poor, only 80-100 ° C. However, boron steel and high boron steel will react to form eutectic boride Fe ₂ B, which is easy to nucleate at the grain boundary and weaken the mechanical properties of the material. At the same time, the shielding performance of this type of alloy is not affected by the solid solubility. However, efficient and stable nuclear shielding materials should not only have high γ-ray and neutron shielding performance, but also require good toughness. The form of aluminum-based composite materials not only has the characteristics of controllable mesoscopic shape and large content adjustable range of added shielding components, but also can maintain good mechanical properties and heat resistance, and is lower than traditional shielding materials. The specific gravity, which has great advantages in later material molding and engineering use.

In view of the toxicity hazard of lead element, the present invention uses heavy nuclear element tungsten as gamma ray shielding component, and uses boron-containing particles and/or gadolinium-containing particles to achieve good neutron absorption effect. However, the tungsten element in the existing tungsten-containing nuclear shielding composite materials is mainly added in the form of particles, and the plasticity of the composite material will decrease significantly with the increase of the content of tungsten particles.

For example, in patent CN110527887B, tungsten and/or tungsten carbide and one or both of boron, boron carbide and boron nitride are ball-milled with aluminum alloy powder and then spark plasma sintered to obtain a composite material.

In order to improve the shielding performance of the composite material, it is necessary to increase the content of tungsten and/or tungsten carbide, which will inevitably lead to a significant decline in the mechanical properties of the composite material, and it is difficult to meet the needs of structural and functional integration, and there is a long ball milling time, and the size of the sample prepared by spark plasma sintering small problem.

Therefore, in the present invention, the granular reinforcement is changed to a mesh-like braided tungsten wire, and the tungsten mesh toughened aluminum-based composite material is prepared by a pressure infiltration method, in order to reduce the contribution of the reinforcement to the brittleness of the composite material, while ensuring the shielding performance of the material. At the same time, the strength and toughness of the material are improved.

In summary, it is imperative and promising to develop a structure-functional integrated nuclear shielding material that has comprehensive shielding capabilities against γ-rays and neutrons, and has good mechanical properties.

Contents of the invention

The purpose of the present invention is to provide a tungsten mesh toughened aluminum-based composite nuclear shielding material and its preparation method, which can prepare a structure-functional integrated nuclear material with comprehensive shielding ability for gamma rays and neutrons and good mechanical properties. shielding material.

The purpose of the present invention is achieved through the following technical solutions:

A tungsten mesh toughened aluminum-based composite nuclear shielding material, the composite material uses boron-containing and/or gadolinium-containing particles as neutron-absorbing components, tungsten mesh as gamma-ray-absorbing components, and aluminum metal as a matrix; wherein The volume fraction of boron and/or gadolinium-containing particles is 1% to 20%, the volume fraction of tungsten mesh is 1% to 50%, and the volume fraction of aluminum metal matrix is 30% to 98%;

The aluminum metal matrix is pure aluminum or aluminum alloy, the boron-containing particles are pure boron powder and/or boron carbide powder, the particle size of the boron-containing powder is 0.1-30 μm, and the gadolinium-containing particles are pure gadolinium powder and/or boron carbide powder. Gadolinium powder, the particle size of the gadolinium-containing powder is 0.1-50 μm, the tungsten mesh is 10-500 mesh, and the wire diameter is 5 μm-1mm;

A method for preparing a tungsten mesh toughened aluminum-based composite nuclear shielding material, the method comprising the following steps:

Step 1: Select and process tungsten mesh: According to the material design requirements, select a tungsten mesh with a mesh number of 10 mesh to 500 mesh and a wire diameter of 5 μm to 1mm, and put the tungsten mesh in a cleaning agent to remove impurities and oxidation on the surface layer; the cleaning agent is concentrated alkali or concentrated acid solution;

Step 2: preparing a neutron absorber suspension; the neutron absorber suspension is a suspension of boron-containing powder and/or gadolinium-containing powder and absolute ethanol with a concentration of 100% to 700%;

Step 3: Cut the cleaned tungsten mesh into a certain shape and size, and stack according to the material design requirements in accordance with the layering methods such as staggered layering and sequential layering and the layering angle of 0-90°. Each layer of tungsten mesh is laid with Brush the neutron absorber suspension on the surface of the tungsten mesh, weigh it to determine the amount of neutron absorber added; clamp the arranged tungsten mesh up and down with graphite gaskets, and fix it with bolts; then place it Dry in a drying oven at 50°C to 100°C for 5 to 20 minutes;

Step 4: The tungsten mesh preform is pressed into the steel mold with a press;

Step 5: Transfer the tungsten mesh preform together with the steel mold to the heating furnace, raise the temperature of the heating furnace from room temperature to 500°C-700°C and keep it warm for 10-120 minutes to obtain a preheated tungsten mesh preform; Aluminum metal is heated at 700°C to 900°C until it melts;

Step 6: Place the preheated tungsten mesh prefabricated body on the press table, and pour molten aluminum metal onto the preheated tungsten mesh prefabricated body in the steel mold;

Step 7: Apply pressure through a press to impregnate the molten aluminum metal into the preheated tungsten mesh prefabricated body, and the pressure is 30-80MPa;

Step 8: The molten aluminum metal is completely impregnated into the preheated tungsten mesh prefabricated body, keeping the pressure for 1-5 minutes and cooling naturally;

Step 9: Demoulding, taking out the ingot, which is the tungsten mesh toughened aluminum matrix composite material;

The beneficial effects of the present invention are:

In the present invention, boron-containing particles and/or gadolinium-containing particles are used as neutron-absorbing components, tungsten mesh is used as gamma-ray-absorbing components, and aluminum metal is infiltrated into boron- and/or gadolinium-containing tungsten mesh prefabricated body by pressure infiltration process , the prepared composite material has the characteristics of high density, good strength and toughness, and good comprehensive shielding effect of γ-ray and neutron radiation, which meets the requirements of nuclear shielding material structure and function integration.

The tungsten mesh toughened aluminum-based composite material prepared by the invention has the function of shielding gamma rays and neutrons. The volume fraction of tungsten is 1% to 50%, and the density is greater than 99%. The gamma ray shielding performance of the composite material increases with the increase of tungsten content. When the tungsten volume fraction is greater than 20%, the gamma ray absorption coefficient of the composite material is greater than 0.3cm-1; at this time, if it is added in the form of tungsten particles, the pull The composite material is brittle and fractured under tensile stress, and the elongation at break is less than 0.5%. If it is added in the form of tungsten mesh, the elongation at fracture of the composite material can reach 2-5% under tensile stress, which can better meet the structure of shielding materials. Functional integration requirements. The invention provides a method for preparing a tungsten mesh toughened aluminum-based composite material with gamma-ray and neutron shielding functions. The preparation method is simple, easy to operate, and the process is easy to control. The prepared composite material has high density, good toughness, and Combines neutron and gamma ray shielding properties.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific implementation methods.

Fig. 1 is the schematic diagram of the microstructure of the tungsten mesh toughened aluminum-based composite nuclear shielding material of the present invention;

Fig. 2 is a schematic diagram comparing the tensile stress-strain curves of the tungsten-boron-aluminum composite material with a volume fraction of tungsten particles of 20% and the tungsten mesh toughened aluminum-based composite nuclear shielding material with a volume fraction of tungsten mesh of 20% according to the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

In order to prepare a structure-functional integrated nuclear shielding material with comprehensive shielding ability for γ-rays and neutrons and good mechanical properties, as shown in Figure 1, a tungsten mesh toughened aluminum-based composite nuclear shielding material is The steps and functions of the material preparation method are described in detail;

Embodiment one:

Weigh 24.1% tungsten mesh and 3% boron powder according to the volume fraction, wherein the tungsten mesh includes two types of 100 mesh and 150 mesh, and mix the weighed boron powder and absolute ethanol to form a boron-containing suspension with a concentration of 500%. At the same time, clean the tungsten mesh with different meshes in concentrated alkali and cut it into the desired shape and size; brush the boron-containing suspension on the surface of the tungsten mesh with a brush and put it in a drying oven at 50°C Dry in medium for 10 minutes, and then weigh to determine the content of boron particles attached to the tungsten mesh until the content meets the shielding performance requirements. Then stack 100 mesh and 150 mesh boron-containing tungsten mesh according to the staggered stacking method and 0° layering angle, clamp the stacked tungsten mesh up and down with graphite gaskets, and fix the prefabricated parts with bolts; Press into the steel mold, and then transfer to a heating furnace at 650°C for 90 minutes to obtain a preheated tungsten mesh preform; at the same time, heat the aluminum matrix at 890°C to melt and cast it on the preheated body in the steel mold, Apply pressure through a press to impregnate the molten aluminum matrix into the preheated tungsten mesh preform, keep the pressure and cool naturally; finally demoulding and taking out the ingot to obtain the boron/tungsten mesh/aluminum composite shielding material;

Embodiment two:

Weigh 24.1% tungsten mesh and 3% boron powder according to the volume fraction, wherein the tungsten mesh includes two types of 100 mesh and 150 mesh, and mix the weighed boron powder and absolute ethanol to form a boron-containing suspension with a concentration of 500%. At the same time, clean the tungsten mesh with different meshes in concentrated alkali and cut it into the desired shape and size; brush the boron-containing suspension on the surface of the tungsten mesh with a brush and put it in a drying oven at 50°C Dry in medium for 10 minutes, and then weigh to determine the content of boron particles attached to the tungsten mesh until the content meets the shielding performance requirements. Then the 100 mesh and 150 mesh boron-containing tungsten meshes are stacked according to the staggered stacking method and the layering angle of 45°, and the stacked tungsten meshes are clamped up and down with graphite gaskets, and the prefabricated parts are obtained by fixing them with bolts; Press into the steel mold, and then transfer to a heating furnace at 700°C for 90 minutes to obtain a preheated tungsten mesh preform; at the same time, heat the aluminum matrix at 890°C to melt and cast it on the preheated body in the steel mold, Apply pressure through a press to impregnate the molten aluminum matrix into the preheated tungsten mesh preform, keep the pressure and cool naturally; finally demoulding and taking out the ingot to obtain the boron/tungsten mesh/aluminum composite shielding material.

Claims (10)

1. A tungsten mesh toughened aluminum-based composite nuclear shielding material is characterized in that: the composite material takes boron-containing and/or gadolinium-containing particles as neutron absorption components, takes tungsten mesh as gamma ray absorption components, and takes aluminum metal as a matrix;

wherein the volume fraction of the boron-containing and/or gadolinium-containing particles is 1-20%, the volume fraction of the tungsten mesh is 1-50%, and the volume fraction of the aluminum metal matrix is 30-98%.

2. The tungsten mesh toughened aluminum-based composite nuclear shielding material as claimed in claim 1, wherein: the aluminum metal matrix is pure aluminum or aluminum alloy, the boron-containing particles are pure boron powder and/or boron carbide powder, the particle size of the boron-containing powder is 0.1-30 mu m, the gadolinium-containing particles are pure gadolinium powder and/or gadolinium oxide powder, the particle size of the gadolinium-containing powder is 0.1-50 mu m, the tungsten mesh is 10-500 meshes, and the wire diameter is 5 mu m-1 mm.

3. A preparation method of a tungsten mesh toughened aluminum-based composite nuclear shielding material is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: selecting a treatment tungsten net:

step two: preparing a neutron absorber suspension;

step three: cutting the tungsten mesh into layers, then laminating, brushing a neutron absorber suspension on the surface of each layer of tungsten mesh, and drying to form a tungsten mesh prefabricated part;

step four: pressing the tungsten mesh prefabricated part into a steel mould;

step five: preheating the tungsten mesh prefabricated part and melting aluminum metal;

step six: molten aluminum metal is cast on the preheated tungsten mesh prefabricated part;

step seven: pressurizing to enable molten aluminum metal to be infiltrated into the preheated tungsten mesh prefabricated body;

step eight: keeping the pressure and naturally cooling to prepare the tungsten mesh toughened aluminum-based composite nuclear shielding material.

4. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: in the first step, a tungsten net with the mesh number of 10-500 meshes and the wire diameter of 5 mu m-1 mm is selected and put into a cleaning agent for cleaning so as to remove impurities and oxide layers on the surface.

5. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: the neutron absorber suspension is 100% -700% suspension prepared from boron-containing powder and/or gadolinium-containing powder and absolute ethyl alcohol.

6. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: in the third step, the tungsten mesh stacking mode is staggered stacking and sequential stacking, and the stacking angle is 0-90 degrees.

7. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: in the third step, the drying temperature is 50-100 ℃, and the drying time is 5-20 min.

8. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: in the fifth step, the preheating temperature of the tungsten mesh prefabricated part is 500-700 ℃, the preheating time is 10-120 min, and the melting temperature of aluminum metal is 700-900 ℃.

9. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: and in the seventh step, the pressure of the molten aluminum metal infiltrated into the preheated tungsten mesh preform is 30-80 MPa.

10. The preparation method of the tungsten mesh toughened aluminum-based composite nuclear shielding material according to claim 3, characterized by comprising the following steps: in the step eight, the time for keeping the pressure is 1-5 min.

Images