Particle-reinforced tungsten-based alloy, preparation method and application

Abstract

The invention discloses a particle reinforced tungsten-based alloy, a preparation method and application, the tungsten-based alloy comprises tungsten and europium hexaboride, and the mass fraction of the europium hexaboride in the tungsten-based alloy is 0.1 wt%-4wt%. Europium hexaboride is introduced into the particle-reinforced tungsten-based alloy provided by the invention, the shielding capability on neutron irradiation is improved, europium hexaboride particles are dispersed and distributed in a tungsten matrix, the mechanical property of the tungsten-based alloy can be enhanced, and the tungsten-based alloy has good mechanical property.

Description

Technical Field

[0001] The present invention relates to the field of metallurgy technology, and in particular to a particle-reinforced tungsten-based alloy, a preparation method and applications thereof. Background Art

[0002] When a nuclear reactor is operating, the core will produce a variety of radiation (α, β, γ, χ) as well as neutrons (n), protons (p), deuterium nuclei (d), and fission products (FP). Among them, radiation (γ) and neutrons have strong penetrating power. If they are not properly shielded, they will cause certain radiation damage to surrounding objects and personnel.

[0003] Tungsten is an excellent material for radiation shielding, and its radiation shielding ability is three times that of lead. It has significant advantages in the field of shielding parts and can effectively shield various radiations, including gamma rays. However, tungsten has poor neutron shielding ability and cannot meet the requirements of shielding both radiation and neutron radiation.

[0004] Therefore, it is necessary to provide a particle-reinforced tungsten alloy shielding material having good neutron shielding capability and being easy to process and produce, as well as a preparation method and application thereof.

[0005] In view of this, a particle reinforced tungsten-based alloy with strong neutron shielding capability and good mechanical properties is provided. Summary of the Invention

[0006] The purpose of the present invention is to provide a particle-reinforced tungsten-based alloy, a preparation method and an application thereof, so as to overcome the problem that tungsten has no neutron shielding capability.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a particle-reinforced tungsten-based alloy, wherein the tungsten-based alloy comprises tungsten and europium hexaboride, and the mass fraction of europium hexaboride in the tungsten-based alloy is 0.1%-4wt%.

[0009] In an optional embodiment, the thermal conductivity of the particle-reinforced tungsten-based alloy at 25° C. is greater than 140 W / mK;

[0010] and / or, the neutron transmittance of the particle-reinforced tungsten-based alloy is less than 17%;

[0011] And / or, the hardness of the particle-reinforced tungsten-based alloy is greater than 430.

[0012] In a second aspect, the present invention provides a use of the particle-reinforced tungsten-based alloy described in the aforementioned embodiment in a radiation shielding or neutron shielding component.

[0013] In a third aspect, the present invention provides a method for preparing the particle-reinforced tungsten-based alloy described in the aforementioned embodiment, comprising: sequentially performing cold isostatic pressing, sintering, plastic working and annealing on a mixed powder containing tungsten powder and europium hexaboride to obtain the particle-reinforced tungsten-based alloy.

[0014] In an optional embodiment, the method for preparing the mixed powder includes: mixing tungsten powder and europium hexaboride to obtain the mixed powder.

[0015] In an optional embodiment, the ball milling time is 30 hours to 72 hours.

[0016] In an optional embodiment, the pressure in the cold isostatic pressing step is 180 MPa-250 MPa.

[0017] In an optional embodiment, the sintering temperature is 1800° C.-2400° C., and the holding time of the sintering step is 2 h-8 h;

[0018] And / or, the sintering step is performed in a medium frequency sintering furnace or a hot pressing furnace.

[0019] In an optional embodiment, the plastic working method includes rotary forging or rolling, and the deformation amount of the plastic working step is 52%-88%.

[0020] In an optional embodiment, the annealing temperature is 1160° C.-1240° C., and the holding time of the annealing step is 1 h-2 h.

[0021] The present invention has the following beneficial effects:

[0022] The particle-reinforced tungsten-based alloy provided in the present application introduces europium hexaboride to improve the shielding ability of the tungsten-based alloy against neutron irradiation. The europium hexaboride particles are dispersed in the tungsten matrix, which can enhance the mechanical properties of the tungsten-based alloy and make the tungsten-based alloy have good mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a SEM image of the fracture surface of the particle-reinforced tungsten-based alloy prepared in Example 1;

[0025] Figure 2 This is the SEM image of the fracture of the particle-reinforced tungsten-based alloy prepared in Example 2. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0027] An embodiment of the present invention provides a particle-reinforced tungsten-based alloy. The tungsten-based alloy comprises tungsten and europium hexaboride. The mass fraction of europium hexaboride in the tungsten-based alloy is 0.1 wt%-4 wt%.

[0028] Specifically, the mass fraction of europium hexaboride can be 0.1 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, 0.35 wt%, 0.40 wt% or any value between 0.1 wt% and 4 wt%.

[0029] The particle-reinforced tungsten-based alloy provided in the present application introduces europium hexaboride to improve the shielding ability of the tungsten-based alloy against neutron irradiation. The europium hexaboride particles are dispersed in the tungsten matrix, which can enhance the mechanical properties of the tungsten-based alloy and make the tungsten-based alloy have good mechanical properties.

[0030] In an optional embodiment, the thermal conductivity of the particle-reinforced tungsten-based alloy at 25° C. is greater than 140 W / mK;

[0031] and / or, the neutron transmittance of the particle-reinforced tungsten-based alloy is less than 17%;

[0032] And / or, the particle-reinforced tungsten-based alloy has a Vickers hardness greater than 430.

[0033] An embodiment of the present invention further provides a use of the particle-reinforced tungsten-based alloy described in the aforementioned embodiment in a radiation shielding or neutron shielding component.

[0034] An embodiment of the present invention also provides a method for preparing the particle-reinforced tungsten-based alloy described in the aforementioned embodiment, comprising: sequentially performing cold isostatic pressing, sintering, plastic working and annealing on a mixed powder containing tungsten powder and europium hexaboride to obtain the particle-reinforced tungsten-based alloy.

[0035] In an optional embodiment, the preparation method of the mixed powder includes: mixing tungsten powder and europium hexaboride to obtain the mixed powder. Specifically, the mixing method can be ball milling or other mechanical mixing methods.

[0036] In this embodiment, the particle size of the tungsten powder can be 2-5 μm, and the particle size of the europium hexaboride can be 0.1 μm-40 μm. High-energy ball milling can be used. The smaller particle size of europium hexaboride is conducive to its uniform distribution in the alloy and reduces the grain size of the particle-reinforced tungsten-based alloy.

[0037] In an optional embodiment, the ball milling time is 30 h-72 h, specifically 30 h, 40 h, 50 h, 60 h, 72 h or any value between 30 h and 72 h.

[0038] In an optional embodiment, the pressure of the cold isostatic pressing step is 180 MPa-250 MPa, specifically 180 MPa, 190 MPa, 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa or any value between 180 MPa and 250 MPa.

[0039] In an optional embodiment, the sintering temperature is 1800°C-2400°C, and the holding time of the sintering step is 5h-8h; specifically, the sintering temperature can be 1800°C, 1900°C, 2000°C, 2100°C, 2200°C, 2300°C, 2400°C or any value between 1800°C and 2400°C; the holding time of the sintering step can be 2h, 3h, 4h, 5h, 6h, 7h, 8h or any value between 2h and 8h.

[0040] And / or, the sintering step is performed in a medium frequency sintering furnace or a hot pressing furnace.

[0041] In an optional embodiment, the plastic processing method includes rotary forging or rolling, and the deformation amount of the plastic processing step is 52%-88%, specifically, it can be 52%, 60%, 70%, 80%, 88% or any value between 52% and 88%.

[0042] In an optional embodiment, the annealing temperature is 1160°C-1240°C, and the holding time of the annealing step is 1h-2h. Specifically, the annealing temperature can be 1160°C, 1170°C, 1180°C, 1190°C, 1200°C, 1210°C, 1220°C, 1230°C, 1240°C or any value between 1160°C and 1240°C; the annealing time can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h or any value between 1h and 2h.

[0043] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0044] Example 1

[0045] This embodiment provides a method for preparing a particle-reinforced tungsten-based alloy, comprising:

[0046] 1. Weigh europium hexaboride (average particle size 10 μm) and tungsten powder (average particle size 3 μm) in a 10% mass ratio and ball-mill for 50 hours at a speed of 200 rpm, with a ball-to-material ratio of 10:1. Pour the ball-milled material into a V-type powder mixer, then continue to add tungsten powder of the same particle size, with the weight ratio of the newly added tungsten powder to the ball-milled material being 9:1. Mix for 12 hours. At this point, the mass of europium hexaboride in the V-type powder mixer is 1% of the total mass.

[0047] 2. Use cold isostatic press with a pressing force of 220 MPa and a pressing time of 180 seconds;

[0048] 3. Use a medium frequency induction furnace for sintering at a temperature of 2350°C for 6 hours to obtain a sintered alloy;

[0049] 4. Rolling the sintered alloy with a rolling deformation of 70% and a rolling temperature of 1600° C. to obtain a rolled alloy;

[0050] 5. The rolled alloy is annealed at a temperature of 1200° C. for 1.5 hours to obtain a particle-reinforced tungsten-based alloy.

[0051] Example 2

[0052] This embodiment provides a method for preparing a particle-reinforced tungsten-based alloy, comprising:

[0053] 1. Weigh europium hexaboride (average particle size of 0.1 μm) and tungsten powder (average particle size of 3 μm) at a mass ratio of 0.5% and mix them in a V-shaped powder mixer for 30 hours;

[0054] 2. Use cold isostatic press with a pressing force of 200 MPa and a pressing time of 150 s;

[0055] 3. Use a hot pressing sintering furnace for sintering at a temperature of 1800°C and a pressure of 30 MPa for 5 hours to obtain a sintered alloy;

[0056] 4. Rolling the sintered alloy with a rolling deformation of 52% and a rolling temperature of 1550° C. to obtain a rolled alloy;

[0057] 5. The rolled alloy is annealed at a temperature of 1200° C. for 2 hours to obtain a particle-reinforced tungsten-based alloy.

[0058] Example 3

[0059] This embodiment provides a method for preparing a particle-reinforced tungsten-based alloy, comprising:

[0060] 1. Weigh 4% by mass of europium hexaboride (average particle size of 1 μm) and tungsten powder (average particle size of 6.5 μm) and mix them by ball milling for 72 h at a speed of 220 rpm and a ball-to-material ratio of 20:1.

[0061] 3. Use a hot pressing sintering furnace for sintering at a temperature of 1800°C and a pressure of 30 MPa, and keep warm for 2 hours to obtain a sintered alloy;

[0062] 4. Rolling the sintered alloy with a rolling deformation of 88% and a rolling temperature of 1600° C. to obtain a rolled alloy;

[0063] 5. Annealing the rolled alloy at 1200°C for 1 hour to obtain a particle-reinforced tungsten-based alloy.

[0064] Example 4

[0065] This embodiment provides a method for preparing a particle-reinforced tungsten-based alloy, which differs from Example 1 only in that the content of europium hexaboride in the tungsten-based alloy is 0.1 wt %.

[0066] Comparative Example 1

[0067] This comparative example provides a method for preparing a particle-reinforced tungsten-based alloy, which differs from Example 1 in that europium hexaboride is not added.

[0068] Comparative Example 2

[0069] This comparative example provides a method for preparing a particle-reinforced tungsten-based alloy, which differs from Example 1 in that an equal mass of lanthanum hexaboride is used instead of europium hexaboride.

[0070] Comparative Example 3

[0071] This comparative example provides a preparation method of a particle-reinforced tungsten-based alloy, which differs from Example 1 in that the amount of europium hexaboride added to the particle-reinforced tungsten-based alloy is 6 wt %.

[0072] The particle-reinforced tungsten-based alloys prepared in Example 1, Comparative Example 1, and Comparative Example 2 were tested for neutron shielding capability. The neutron transmittance test method was based on the Beijing Radiation Application Research Center Enterprise Standard "Q / CYSXY001-2016". The test results are shown in Table 1:

[0073] Table 1

[0074] Neutron transmittance Example 1 6.4％ Comparative Example 1 17％ Comparative Example 2 12.5％

[0075] As can be seen from Table 1, compared with the tungsten-based alloy of Comparative Example 1 without adding europium hexaboride and the tungsten-based alloy of Comparative Example 2 with adding 1wt% lanthanum hexaboride, the tungsten-based alloy of Example 1 has a significantly decreased neutron transmittance by adding 1wt% europium hexaboride, indicating that the neutron shielding performance of the tungsten-based alloy can be significantly improved by adding europium hexaboride.

[0076] The thermal conductivity and hardness of the particle-reinforced tungsten-based alloys prepared in each embodiment and comparative example were tested.

[0077] Thermal conductivity test method: GB / T22588-2008 "Flash method for measuring thermal diffusivity or thermal conductivity";

[0078] Hardness measurement method: GB / T4340 "Vickers hardness test for metallic materials".

[0079] The test results are shown in Table 2.

[0080] Table 2

[0081]

[0082]

[0083] Note: The tungsten-based alloy prepared in Comparative Example 3 cracked during rolling and did not meet the standard, so the Vickers hardness was not tested again.

[0084] As can be seen from Table 2, the particle-reinforced tungsten-based alloy prepared in this application can take into account both thermal conductivity and hardness and has good mechanical properties. In addition, the SEM images of the particle-reinforced tungsten-based alloy prepared in Example 1 and Example 2 are as follows: Figure 1 and Figure 2 As shown in the figure, it can be seen that the prepared particle reinforced tungsten-based alloy has partial ductile dimple fracture characteristics, which is beneficial to further improve the comprehensive mechanical properties of tungsten-based alloy.

[0085] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A particle-reinforced tungsten-based alloy, characterized in that: The tungsten-based alloy comprises tungsten and europium hexaboride, and the mass fraction of europium hexaboride in the tungsten-based alloy is 0.1 wt%-4 wt%.

2. The particle-reinforced tungsten-based alloy according to claim 1, characterized in that: The thermal conductivity of the particle-reinforced tungsten-based alloy at 25° C. is greater than 140 W / mK; and / or, the neutron transmittance of the particle-reinforced tungsten-based alloy is less than 17%; And / or, the particle-reinforced tungsten-based alloy has a Vickers hardness greater than 430.

3. Use of the particle-reinforced tungsten-based alloy according to claim 1 or 2 in radiation and / or neutron shielding components.

4. A method for preparing a particle-reinforced tungsten-based alloy according to claim 1 or 2, characterized in that: include: The mixed powder containing tungsten powder and europium hexaboride is subjected to cold isostatic pressing, sintering, plastic working and annealing in sequence to obtain the particle-reinforced tungsten-based alloy.

5. The method for preparing a particle-reinforced tungsten-based alloy according to claim 4, characterized in that: The preparation method of the mixed powder includes: mixing tungsten powder and europium hexaboride to obtain the mixed powder.

6. The method for preparing a particle-reinforced tungsten-based alloy according to claim 5, characterized in that: The ball milling time is 30h-72h.

7. The method for preparing a particle-reinforced tungsten-based alloy according to claim 4, characterized in that: The pressure in the cold isostatic pressing step is 180 MPa-250 MPa.

8. The method for preparing a particle-reinforced tungsten-based alloy according to claim 4, wherein: The sintering temperature is 1800-2400°C, and the holding time of the sintering step is 2h-8h; And / or, the sintering step is performed in a medium frequency sintering furnace or a hot pressing furnace.

9. The method for preparing a particle-reinforced tungsten-based alloy according to claim 4, wherein: The plastic processing method includes rotary forging or rolling, and the deformation amount of the plastic processing step is 52%-88%.

10. The method for preparing a particle-reinforced tungsten-based alloy according to claim 4, characterized in that: The annealing temperature is 1160° C.-1240° C., and the holding time of the annealing step is 1 h-2 h.

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