High-toughness magnesium-based composite material with neutron radiation shielding capability

Abstract

The invention belongs to the technical field of alloy materials, and provides a high-toughness magnesium-based composite material with neutron radiation shielding capability. By optimizing the component design and the thermal deformation strengthening process of the magnesium-based composite material, the technical problems that in the prior art, a traditional neutron shielding material is large in mass, poor in mechanical property and low in shielding efficiency, and light weight and structural function integration cannot be considered at the same time are solved. The thermal neutron shielding material has the beneficial effects that the thermal neutron transmissivity is as low as 3.42 * 10 <-5 > under the thickness of 5 mm, meanwhile, the thermal neutron shielding material has the beneficial effects of high strength, toughness and light weight, the neutron shielding property and the mechanical property are synergistically improved, and the thermal neutron shielding material is suitable for aerospace radiation protection, nuclear facility containers and other scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a high-strength and tough magnesium-based composite material with neutron radiation shielding capability. Background Art

[0002] With the growing demand for aerospace radiation protection and safe storage and transportation of nuclear facilities, there is an urgent need for structurally functional integrated materials that are lightweight, high-strength and toughness, and have efficient neutron shielding capabilities.

[0003] In the existing technology, traditional neutron shielding materials mainly include two categories: heavy materials (such as boron steel and gadolinium-containing stainless steel): they require a large thickness or mass to achieve shielding, resulting in bulky materials and poor processing performance, which cannot meet the lightweight requirements; lightweight materials (such as rare earth magnesium alloy Mg-Gd-Zr): low density, about 1 / 4 of steel, but its thermal neutron transmittance is as high as 0.2, and the shielding performance is insufficient, as shown in the comparative example. In addition, single functional materials, such as boron carbide and polyethylene, have good shielding effects, but poor mechanical properties and cannot be used as independent structural materials.

[0004] Based on the defects of the prior art, the present invention achieves high strength and toughness and efficient neutron shielding performance while being lightweight through the coordinated design of material composition and process. Summary of the invention

[0005] The present invention provides a high-strength and tough magnesium-based composite material with neutron radiation shielding capability, which is used to solve the technical problems of traditional neutron shielding materials in the prior art, such as large mass, poor mechanical properties, low shielding efficiency and inability to take into account both lightweight and structural functional integration.

[0006] The present invention provides a high-strength and tough magnesium-based composite material with neutron radiation shielding capability, which is composed of the following components in mass percentage: Gadolinium 0.1~8wt%; Yttrium 0.1~4wt%; Zirconium 0.1~0.7wt%; Boron carbide ceramic particles 1~5wt%; The balance is magnesium and unavoidable impurities; The preparation method of the composite material comprises the following steps: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0007] According to the present invention, a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability comprises the following steps: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0008] According to a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the particle size of the boron carbide ceramic particles is 2-8 μm.

[0009] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the mixed gas is a mixed gas of SF6:CO2=1:45~55.

[0010] According to the method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the temperature of the preheating treatment in step (1) is 150-250°C.

[0011] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the initial temperature for smelting pure magnesium in step (2) is 600-800°C, and after adding the intermediate alloy, the temperature is raised to 650-850°C, and the insulation treatment time is 20-30 minutes.

[0012] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the preset temperature in step (3) is 550-650° C., the stirring speed is 400-600 rpm, and the boron carbide ceramic particles are added in 3-10 times.

[0013] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the stirring speed in the step (4) is 800-1000 rpm, the stirring treatment time is 5-15 min, and the melt temperature is maintained at 560-670°C during the stirring treatment.

[0014] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the stirring speed in the step (5) is 400-600 rpm, the preset temperature is 550-750°C, the reverse stirring speed is 400-600 rpm, the reverse stirring time is 1-3 min, and the mold is preheated to 150-250°C.

[0015] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the temperature of the heat preservation treatment in the step (6) is 350-550° C., the time of the heat preservation treatment is 40-80 min, the deformation amount of the forging is 70-90%, and the deformation strain rate is 0.003-0.007% / s.

[0016] The high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention solves the technical problems of large mass, poor mechanical properties, low shielding efficiency and inability to combine lightweight and structural function in the conventional neutron shielding materials in the prior art by optimizing the composition design and thermal deformation strengthening process of the magnesium-based composite material, and achieves a thermal neutron transmittance as low as 3.42×10 -5It has the beneficial effects of high strength, toughness and lightweight at the same time, achieving a synergistic improvement in neutron shielding performance and mechanical properties, and is suitable for scenarios such as aerospace radiation protection and nuclear facility containers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a SEM microstructure diagram of a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by an embodiment of the present invention; Figure 2 This is an EDS element spectrum of a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by an embodiment of the present invention; Figure 3 is a particle size distribution histogram of boron carbide ceramic particles of a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by an embodiment of the present invention; Figure 4 This is an XRD energy spectrum of a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention provides a high-strength and tough magnesium-based composite material with neutron radiation shielding capability, which is composed of the following components in mass percentage: Gadolinium 0.1~8wt%; Yttrium 0.1~4wt%; Zirconium 0.1~0.7wt%; Boron carbide ceramic particles 1~5wt%; The balance is magnesium and unavoidable impurities; The preparation method of the composite material comprises the following steps: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0021] According to the present invention, a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability comprises the following steps: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0022] According to a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the particle size of the boron carbide ceramic particles is 2-8 μm, preferably 3-7 μm, and more preferably 4-6 μm.

[0023] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the mixed gas is a mixed gas of SF6:CO2=1:45~55, preferably SF6:CO2=1:47~53, and further preferably SF6:CO2=1:49~51.

[0024] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the temperature of the preheating treatment in step (1) is 150-250°C, preferably 170-230°C, and more preferably 190-210°C.

[0025] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the initial temperature for smelting pure magnesium in step (2) is 600-800°C, preferably 650-750°C, and more preferably 680-720°C; after adding the intermediate alloy, the temperature is raised to 650-850°C, preferably 700-800°C, and more preferably 740-760°C; and the time for heat preservation treatment is 20-30 min, preferably 22-28 min, and more preferably 24-26 min.

[0026] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the preset temperature in step (3) is 550-650°C, preferably 580-620°C, and more preferably 600-610°C; the stirring speed is 400-600rpm, preferably 450-550rpm, and more preferably 480-520rpm; the boron carbide ceramic particles are added in 3-10 times, preferably 5-8 times, and more preferably 6-7 times.

[0027] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the stirring speed in the step (4) is 800-1000 rpm, preferably 850-950 rpm, and more preferably 880-920 rpm; the stirring treatment time is 5-15 min, preferably 7-13 min, and more preferably 9-11 min; during this period, the melt temperature is maintained at 560-670°C, preferably 580-650°C, and more preferably 610-620°C.

[0028] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the stirring speed in the step (5) is 400-600 rpm, preferably 450-550 rpm, and more preferably 480-520 rpm; the preset temperature is 550-750°C, preferably 600-700°C, and more preferably 640-660°C; the reverse stirring speed is 400-600 rpm, preferably 450-550 rpm, and more preferably 480-520 rpm; the reverse stirring time is 1-3 min; and the mold is preheated to 150-250°C, preferably 170-230°C, and more preferably 190-210°C.

[0029] According to a method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided by the present invention, the temperature of the heat preservation treatment in the step (6) is 350-550°C, preferably 400-500°C, and more preferably 440-460°C; the time of the heat preservation treatment is 40-80 min, preferably 50-70 min, and more preferably 55-65 min; the deformation amount of the forging is 70-90%, preferably 74-86%, and more preferably 78-82%; the deformation strain rate is 0.003-0.007% / s, and more preferably 0.004-0.006% / s.

[0030] Example 1 According to the composition of 6wt% of gadolinium, 3wt% of yttrium, 0.5wt% of zirconium and 2wt% of boron carbide ceramic particles, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles were weighed and preheated at 200°C; Use a talcum powder: water glass = 75:1 aqueous solution to coat the crucible and dry it. Under the protection of SF6:CO2 = 1:50 mixed gas, place the crucible in a resistance furnace, heat it to 700°C to melt pure magnesium, and when the pure magnesium is completely melted, raise the furnace temperature to 750°C, add Mg-30Gd, Mg-30Y and Mg-30Zr in turn, keep it warm for 25 minutes, and remove the surface scum to obtain an alloy melt; Lower the furnace temperature, and when the melt temperature drops to 610°C, quickly insert the stirring paddle, increase the mixed gas flow rate, stir the alloy melt clockwise at a speed of 500 rpm to form a stable vortex, and add the preheated boron carbide ceramic particles into the alloy melt in 6 portions; After adding all the boron carbide ceramic particles, increase the speed to 900 rpm and stir for 10 minutes, during which the melt temperature is maintained at 610°C; The rotation speed is gradually reduced to 500 rpm, and the furnace temperature is increased until the melt temperature reaches 660°C. After reaching the temperature, the stirring paddle is reversed at a speed of 500 rpm for 2 minutes, and the stirring paddle is quickly withdrawn to cast the magnesium-based composite material melt into a mold preheated to 200°C to obtain a magnesium-based composite material ingot; The obtained magnesium-based composite material ingot was removed of unusable parts, preheated to 450°C, kept warm for 60 minutes, and forged at a deformation strain rate of 0.005% / s to a deformation amount of 80%, thereby obtaining a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0031] After testing, the high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided in this embodiment has an elastic modulus of 45 GPa, a yield strength of 178 MPa, a tensile strength of 305 MPa, an elongation of 8.8%, and a thermal neutron transmittance of 5 mm standard plate of 4.29×10 -5 .

[0032] Example 2 According to the composition of 6wt% of gadolinium, 3wt% of yttrium, 0.5wt% of zirconium and 2wt% of boron carbide ceramic particles, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles were weighed and preheated at 200°C; Use a talcum powder: water glass = 75:1 aqueous solution to coat the crucible and dry it. Under the protection of SF6:CO2 = 1:50 mixed gas, place the crucible in a resistance furnace, heat it to 700°C to melt pure magnesium, and when the pure magnesium is completely melted, raise the furnace temperature to 750°C, add Mg-30Gd, Mg-30Y and Mg-30Zr in turn, keep it warm for 25 minutes, and remove the surface scum to obtain an alloy melt; Lower the furnace temperature, and when the melt temperature drops to 610°C, quickly insert the stirring paddle, increase the mixed gas flow rate, stir the alloy melt clockwise at a speed of 500 rpm to form a stable vortex, and add the preheated boron carbide ceramic particles into the alloy melt in 6 portions; After adding all the boron carbide ceramic particles, increase the speed to 900 rpm and stir for 10 minutes, during which the melt temperature is maintained at 610°C; The rotation speed is gradually reduced to 500 rpm, and the furnace temperature is increased until the melt temperature reaches 660°C. After reaching the temperature, the stirring paddle is reversed at a speed of 500 rpm for 2 minutes, and the stirring paddle is quickly withdrawn to cast the magnesium-based composite material melt into a mold preheated to 200°C to obtain a magnesium-based composite material ingot; The obtained magnesium-based composite ingot was preheated to 450°C after removing the unusable part, kept warm for 60 minutes, and forged at a deformation strain rate of 0.005% / s to a deformation amount of 40%, thereby obtaining a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0033] After testing, the high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided in this embodiment has an elastic modulus of 40 GPa, a yield strength of 118 MPa, a tensile strength of 184 MPa, an elongation of 2.8%, and a thermal neutron transmittance of 5 mm standard plate of 4.29×10 -5 .

[0034] Example 3 According to the composition of 12wt% gadolinium, 3wt% yttrium, 0.5wt% zirconium and 5wt% boron carbide ceramic particles, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles were weighed and preheated at 200°C; Use a talcum powder: water glass = 75:1 aqueous solution to coat the crucible and dry it. Under the protection of SF6:CO2 = 1:50 mixed gas, place the crucible in a resistance furnace, heat it to 700°C to melt pure magnesium, and when the pure magnesium is completely melted, raise the furnace temperature to 750°C, add Mg-30Gd, Mg-30Y and Mg-30Zr in turn, keep it warm for 25 minutes, and remove the surface scum to obtain an alloy melt; Lower the furnace temperature, and when the melt temperature drops to 610°C, quickly insert the stirring paddle, increase the mixed gas flow rate, stir the alloy melt clockwise at a speed of 500 rpm to form a stable vortex, and add the preheated boron carbide ceramic particles into the alloy melt in 6 portions; After adding all the boron carbide ceramic particles, increase the speed to 900 rpm and stir for 10 minutes, during which the melt temperature is maintained at 610°C; The rotation speed is gradually reduced to 500 rpm, and the furnace temperature is increased until the melt temperature reaches 660°C. After reaching the temperature, the stirring paddle is reversed at a speed of 500 rpm for 2 minutes, and the stirring paddle is quickly withdrawn to cast the magnesium-based composite material melt into a mold preheated to 200°C to obtain a magnesium-based composite material ingot; The obtained magnesium-based composite material ingot was removed of unusable parts, preheated to 450°C, kept warm for 60 minutes, and forged at a deformation strain rate of 0.005% / s to a deformation amount of 80%, thereby obtaining a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0035] After testing, the high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided in this embodiment has an elastic modulus of 53 GPa, a yield strength of 180 MPa, a tensile strength of 185 MPa, an elongation of 1.3%, and a thermal neutron transmittance of 5 mm standard plate of 4.09 × 10 -5 .

[0036] Example 4 According to the composition of 6wt% gadolinium, 3wt% yttrium, 0.5wt% zirconium and 10wt% boron carbide ceramic particles, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles were weighed and preheated at 200°C; Use a talcum powder: water glass = 75:1 aqueous solution to coat the crucible and dry it. Under the protection of SF6:CO2 = 1:50 mixed gas, place the crucible in a resistance furnace, heat it to 700°C to melt pure magnesium, and when the pure magnesium is completely melted, raise the furnace temperature to 750°C, add Mg-30Gd, Mg-30Y and Mg-30Zr in turn, keep it warm for 25 minutes, and remove the surface scum to obtain an alloy melt; Lower the furnace temperature, and when the melt temperature drops to 610°C, quickly insert the stirring paddle, increase the mixed gas flow rate, stir the alloy melt clockwise at a speed of 500 rpm to form a stable vortex, and add the preheated boron carbide ceramic particles into the alloy melt in 6 portions; After adding all the boron carbide ceramic particles, increase the speed to 900 rpm and stir for 10 minutes, during which the melt temperature is maintained at 610°C; The rotation speed is gradually reduced to 500 rpm, and the furnace temperature is increased until the melt temperature reaches 660°C. After reaching the temperature, the stirring paddle is reversed at a speed of 500 rpm for 2 minutes, and the stirring paddle is quickly withdrawn to cast the magnesium-based composite material melt into a mold preheated to 200°C to obtain a magnesium-based composite material ingot; The obtained magnesium-based composite material ingot was removed of unusable parts, preheated to 450°C, kept warm for 60 minutes, and forged at a deformation strain rate of 0.005% / s to a deformation amount of 80%, thereby obtaining a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

[0037] After testing, the high-strength and tough magnesium-based composite material with neutron radiation shielding capability provided in this embodiment has an elastic modulus of 50 GPa, a yield strength of 162 MPa, a tensile strength of 220 MPa, an elongation of 2.2%, and a thermal neutron transmittance of 3.42×10 -5 .

[0038] Comparative Example 1 According to the composition of 6wt% gadolinium, 3wt% yttrium and 0.5wt% zirconium, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy were weighed and preheated at 200°C; Use a talcum powder: water glass = 75:1 aqueous solution to coat the crucible and dry it. Under the protection of SF6:CO2 = 1:50 mixed gas, place the crucible in a resistance furnace, heat it to 700°C to melt pure magnesium, and when the pure magnesium is completely melted, raise the furnace temperature to 750°C, add Mg-30Gd, Mg-30Y and Mg-30Zr in turn, keep it warm for 25 minutes, and remove the surface scum to obtain an alloy melt; Under the protection of SF6:CO2=1:50 mixed gas, the refining was carried out at 750℃ and stirred vigorously for 15min; The furnace temperature was lowered to 700°C and kept at this temperature for 25 minutes to obtain a purified magnesium alloy melt. After slag removal, the alloy melt was cast into a preheated mold to obtain a magnesium alloy ingot.

[0039] After testing, the magnesium alloy ingot provided in this comparative example has an elastic modulus of 40 GPa, a yield strength of 134 MPa, a tensile strength of 200 MPa, an elongation of 6.0%, and a thermal neutron transmittance of 5 mm reference plate of 0.2.

[0040] It can be seen that compared with Example 2, Example 1 has a different forging process, and the mechanical properties of the obtained materials are quite different, but the shielding properties are consistent; the component compositions and the amounts of added boron carbide ceramic particles in Example 3 and Example 4 are different, and the shielding properties of the obtained materials are improved, but many mechanical properties are sacrificed; the high-strength and tough magnesium-based composite materials with neutron radiation shielding capabilities provided by Examples 1 to 3 have a thermal neutron transmittance at a thickness of 5 mm that is 4 orders of magnitude better than the magnesium alloy ingot provided in Comparative Example 1, achieving a synergistic improvement in neutron shielding performance and mechanical properties.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength and tough magnesium-based composite material with neutron radiation shielding capability, characterized in that: It is composed of the following components in percentage by mass: Gadolinium 0.1~8wt%; Yttrium 0.1~4wt%; Zirconium 0.1~0.7wt%; Boron carbide ceramic particles 1~5wt%; The balance is magnesium and unavoidable impurities; The preparation method of the composite material comprises the following steps: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

2. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 1, characterized in that: The following steps are involved: (1) According to the composition of the high-strength and tough magnesium-based composite material with neutron radiation shielding capability, pure magnesium, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and boron carbide ceramic particles are weighed and preheated; (2) Under the protection of the mixed gas, pure magnesium is melted to obtain a molten magnesium matrix, the furnace temperature is increased, and Mg-30Gd master alloy, Mg-30Y master alloy and Mg-30Zr master alloy are sequentially added to the molten magnesium matrix. After heat preservation treatment, the surface slag is removed to obtain an alloy melt; (3) Under the protection of the mixed gas, when the melt is cooled to a preset temperature, the preheated boron carbide ceramic particles are stirred and added; (4) Under the protection of the mixed gas, increase the stirring speed and keep the mixture warm under stirring; (5) Under the protection of the mixed gas, the stirring speed is reduced, the furnace temperature is increased to a preset temperature, and then the stirring is reversed to obtain a magnesium-based composite material melt, and the magnesium-based composite material melt is cast into a mold to obtain a magnesium-based composite material ingot; (6) After the magnesium-based composite material ingot is subjected to heat preservation treatment, it is forged to obtain a high-strength and tough magnesium-based composite material with neutron radiation shielding capability.

3. The high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 1, characterized in that: The particle size of the boron carbide ceramic particles is 2-8 μm.

4. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: The mixed gas is a mixed gas of SF6:CO2=1:45~55.

5. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: The temperature of the preheating treatment in step (1) is 150-250°C.

6. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: In the step (2), the initial temperature for smelting pure magnesium is 600-800°C, and after adding the intermediate alloy, the temperature is raised to 650-850°C, and the insulation treatment time is 20-30 minutes.

7. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: In the step (3), the preset temperature is 550-650° C., the stirring speed is 400-600 rpm, and the boron carbide ceramic particles are added in 3-10 times.

8. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: The stirring speed in step (4) is 800-1000 rpm, the stirring treatment time is 5-15 min, and the melt temperature is maintained at 560-670° C.

9. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: In the step (5), the stirring speed is 400-600 rpm, the preset temperature is 550-750°C, the reverse stirring speed is 400-600 rpm, the reverse stirring time is 1-3 min, and the mold is preheated to 150-250°C.

10. The method for preparing a high-strength and tough magnesium-based composite material with neutron radiation shielding capability according to claim 2, characterized in that: The temperature of the heat preservation treatment in the step (6) is 350-550° C., the time of the heat preservation treatment is 40-80 min, the deformation amount of the forging is 70-90%, and the deformation strain rate is 0.003-0.007% / s.

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