Preparation method of novel tungsten-based composite material for shielding high-energy gamma rays

Abstract

The invention discloses a preparation method of a novel tungsten-based composite material for shielding high-energy gamma rays, and belongs to the field of refractory metal-based composite materials. According to the invention, W is taken as a matrix, Gd and Hf or oxides, carbides and borides thereof are taken as composite function shielding components, under the combined action of second phase strengthening and solid solution strengthening, the bending strength and fracture toughness of the material are remarkably improved, and meanwhile, the material has a good shielding effect on gamma rays in a wide energy interval. The prepared novel tungsten-based composite material for shielding the high-energy gamma rays has the advantages of fine crystal grains, uniform second phase distribution and excellent shielding capability on the high-energy gamma rays, and the relative density of the novel tungsten-based composite material is gt; the Pb-Pb alloy material has the advantages that the strength of the Pb-Pb alloy material is 98%, the room-temperature hardness of the Pb-Pb alloy material is 4-12 GPa, the bending strength of the Pb-Pb alloy material is 400-1200 MPa, and the 60Co source shielding rate of the Pb-Pb alloy material is 46-56% when the thickness of the Pb-

Description

Technical Field

[0001] This invention belongs to the field of refractory metal matrix composites, specifically relating to a method for preparing a novel tungsten-based composite material for high-energy gamma ray shielding. Background Technology

[0002] Tungsten, as an element with a high atomic number and high density, possesses excellent gamma-ray shielding performance. Compared to lead, which is widely used, lead has extremely poor hardness and structural strength, and is not resistant to high temperatures. When using lead for large containers and equipment, steel is required for the structural framework; otherwise, it will collapse under its own weight, generating secondary bremsstrahlung radiation. Furthermore, lead itself is a source of heavy metal pollution, potentially causing heavy metal poisoning during use. Tungsten, on the other hand, has no heavy metal toxicity, does not produce bremsstrahlung radiation, and its mechanical properties and gamma-ray shielding performance are superior to lead. When the photon energy is below 500 keV, the difference in shielding performance between tungsten and lead is not significant. As the photon energy increases, tungsten's advantage becomes apparent. Under the condition that the attenuation of high-energy gamma rays with energies >2.0 MeV is 90%, the TVL (total volume layer) of Pb is approximately twice that of W, indicating that W has a significant advantage over Pb in shielding performance under high-energy radiation environments.

[0003] However, the current matrix composites have poor shielding effect and stability, and the mechanical properties and corrosion resistance of tungsten also need to be further improved. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by proposing a method for preparing a novel tungsten-based composite material for high-energy gamma ray shielding.

[0005] This invention, based on powder metallurgy, proposes using W as the matrix and rare earth elements Gd, Hf, or their oxides, carbides, and borides as composite functional shielding components to enhance their shielding ability against high-energy gamma rays over a wide energy range. Gadolinium, with an atomic number of 64, is a high-Z element. Gadolinium and its compounds exhibit good attenuation and shielding capabilities against gamma rays, especially low- and medium-energy gamma rays, and form a second phase within the W matrix, significantly refining the grain size. Hafnium, on the other hand, possesses both a high atomic number (Z=72) and a high density (13.3 g / cm³). 3The presence of Hf itself makes it an excellent gamma-ray shield. When Hf and its compounds exist in the W matrix in solid solution or compound form, they can effectively increase the overall electron density of the material, enhancing Compton scattering and photoelectric effect of gamma rays. Furthermore, in the W matrix, Hf tends to dissolve in W or form intermetallic compounds such as W₂Hf with W. These hard second-phase particles can pin grain boundaries and refine grains, achieving a grain refinement strengthening effect to improve mechanical properties. The combined effect of second-phase strengthening and solid solution strengthening of Gd, Hf, or their oxides, carbides, and borides in the tungsten matrix significantly improves the bending strength and fracture toughness of the material, solving the common bottleneck of "high shielding, low toughness" in traditional shielding tungsten alloys. This allows it to withstand certain mechanical and thermal stresses, improving the reliability of engineering applications. This invention uses a ball milling mixing process to uniformly distribute Gd, Hf, or their oxides, carbides, and borides in the W matrix, effectively improving the material's shielding capability against high-energy gamma rays over a wide energy range. The novel tungsten-based composite material for high-energy gamma ray shielding prepared using the technical route of this invention can produce a novel tungsten-based material with fine grains, uniform second-phase distribution, and excellent high-energy gamma ray shielding ability through powder metallurgy sintering alone. The overall process is significantly shortened, and the preparation cost is greatly reduced. The prepared novel tungsten-based composite material for high-energy gamma ray shielding has a relative density >98%, a room temperature hardness of 4~12 GPa, and a flexural strength of 400~1200 MPa. At a thickness of 10 mm, the material exhibits excellent shielding performance against high-energy gamma rays. 60 The Co source shielding efficiency is 46%~56%, which is equivalent to 1.2~1.6 times the shielding capacity of Pb of the same thickness. It also features a simple and efficient process, low overall energy consumption, and controllable microstructure and properties.

[0006] A method for preparing a novel tungsten-based composite material for high-energy gamma ray shielding, the method comprising the following steps:

[0007] I. Weighing materials:

[0008] Weigh out tungsten powder and modified powder to obtain raw materials;

[0009] The modified powder is one or a mixture of several of the following: gadolinium powder, gadolinium oxide powder, gadolinium boride powder, gadolinium carbide powder, hafnium powder, hafnium oxide powder, hafnium boride powder, and hafnium carbide powder.

[0010] II. Powder Mixing:

[0011] After the tungsten powder and the modified powder are initially mixed, they are ball-milled in an inert gas or vacuum environment and then sieved in an inert gas environment to obtain a uniformly mixed composite powder raw material.

[0012] III. Sintering:

[0013] The composite powder raw material is placed in a graphite mold and sintered in an inert gas or vacuum environment to obtain a novel tungsten-based composite material for high-energy gamma ray shielding.

[0014] The present invention has the following beneficial effects:

[0015] I. This invention is the first to propose a novel tungsten-based composite material for high-energy gamma ray shielding and its preparation method. The process of this invention is simple, which greatly reduces the production cost of the novel tungsten-based composite material for high-energy gamma ray shielding. It can obtain tungsten-based shielding materials with excellent shielding performance through a lower cost and a simpler process. Moreover, it has good mechanical properties and can meet the reliability requirements of practical engineering applications.

[0016] II. This invention utilizes a comprehensive planetary ball mill to ensure thorough and uniform mixing of tungsten powder with gadolinium powder, hafnium powder, or their oxides, borides, and carbide powders. By controlling the ball milling process parameters, it effectively avoids adverse factors such as powder particle agglomeration, interparticle cold welding, and caking. This significantly improves the uniformity of the second phase distribution, refines the grain size, and promotes sintering density, thus enhancing the material's shielding efficiency. Employing a powder metallurgy solid-state sintering method, novel tungsten-based composite materials for high-energy gamma ray shielding with different mass fractions are obtained. Simultaneously, it significantly improves the controllability of the production process. By controlling the ball milling process parameters, the possibility of composite powder contamination due to wear of the mixing ball milling media is effectively reduced, ensuring the purity of the novel tungsten-based composite material for high-energy gamma ray shielding. The novel tungsten-based composite material for high-energy gamma ray shielding prepared using this invention has a relative density >98%, a room temperature hardness of 4~12 GPa, and a flexural strength of 400~1200 MPa. At a thickness of 10 mm, the material exhibits excellent performance in... 60 The Co source shielding efficiency is 46%~56%, equivalent to 1.2~1.6 times the shielding ability of Pb of the same thickness. By adjusting the types of Gd and Hf compounds and the preparation process parameters, when 0.5Gd2O30.5HfO2 was selected as the modified powder ratio, the prepared novel tungsten-based composite material has a relative density of 99.21%, a room temperature hardness of 4.6GPa, and a flexural strength of 750MPa. At a thickness of 10mm, the material exhibits excellent performance in... 60 The Co source shielding efficiency is 55.1%, which is 1.59 times the shielding capability of Pb of the same thickness. It exhibits excellent overall performance. Attached Figure Description

[0017] Figure 1SEM images of novel tungsten-based composite materials for high-energy gamma ray shielding with different mass fractions prepared for the examples are shown in the figures. (a) is 5Gd5Hf prepared in Example 1, (b) is 5Gd8Hf prepared in Example 4, (c) is 4Gd2O3 prepared in Example 6, (d) is 6Gd2O3 prepared in Example 7, (e) is 5Gd10HfB2 prepared in Example 9, and (f) is 5Gd20HfB2 prepared in Example 9. Detailed Implementation

[0018] Specific Implementation Method 1: This implementation method is a preparation method of a novel tungsten-based composite material for high-energy gamma ray shielding, including the following steps:

[0019] I. Weighing materials:

[0020] Weigh out tungsten powder and modified powder to obtain raw materials;

[0021] The modified powder is one or a mixture of several of the following: gadolinium powder, gadolinium oxide powder, gadolinium boride powder, gadolinium carbide powder, hafnium powder, hafnium oxide powder, hafnium boride powder, and hafnium carbide powder.

[0022] II. Powder Mixing:

[0023] After the tungsten powder and the modified powder are initially mixed, they are ball-milled in an inert gas or vacuum environment and then sieved in an inert gas environment to obtain a uniformly mixed composite powder raw material.

[0024] III. Sintering:

[0025] The composite powder raw material is placed in a graphite mold and sintered in an inert gas or vacuum environment to obtain a novel tungsten-based composite material for high-energy gamma ray shielding.

[0026] This embodiment proposes using W as the matrix and rare earth elements Gd, Hf, or their oxides, carbides, and borides as composite functional shielding components to enhance their shielding ability against high-energy gamma rays over a wide energy range. Under the combined effect of second-phase strengthening and solid solution strengthening, the flexural strength and fracture toughness of the material are significantly improved, while maintaining good shielding performance against gamma rays over a wide energy range. This invention enables precise control of the Gd and Hf content at different mass fractions over a wide range. The novel tungsten-based composite material for high-energy gamma ray shielding prepared in this invention has the advantages of fine grains, uniform second-phase distribution, and excellent shielding ability against high-energy gamma rays. Its relative density is >98%, room temperature hardness is 4~12 GPa, flexural strength is 400~1200 MPa, and the material, at a thickness of 10 mm, exhibits excellent shielding performance against high-energy gamma rays. 60 The Co source shielding efficiency is 46%~56%, which is equivalent to 1.2~1.6 times the shielding ability of Pb of the same thickness.

[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass fraction of the modified powder in the raw materials mentioned in step one is 0.1% to 30%. The other steps are the same as in Specific Implementation Method One.

[0028] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the ball milling process described in step two is as follows: An omnidirectional planetary ball mill is used, with a ball-to-material ratio of (5~20):1, a ball mill speed of 50 r / min~500 r / min, and a milling time of 12 h~48 h. Both the grinding jar and the grinding balls are made of cemented carbide. Other steps are the same as in Specific Implementation Method One or Two.

[0029] Furthermore, the ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 10:1, the speed of the ball mill is 300 r / min, the milling time is 12 h, and the material of the grinding jar and the grinding balls is cemented carbide.

[0030] Furthermore, the ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the rotation speed of the ball mill is 200 r / min, the ball milling time is 24 h, and the material of the grinding jar and the grinding balls is cemented carbide.

[0031] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the inert gas mentioned in step two is argon, helium, or krypton; the sieving in step two is sieve sieve sieve 80-320 mesh. Other steps are the same as in Specific Implementation Methods One to Three.

[0032] Specific Implementation Method Five: The difference between this implementation method and Specific Implementation Methods One to Four is that the sintering described in step three is hot pressing sintering. The other steps are the same as in Specific Implementation Methods One to Four.

[0033] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the hot-pressing sintering process is as follows: The temperature is raised from room temperature to 1600℃~2200℃, held at 1600℃~2200℃ for 10min~120min, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 20MPa~100MPa when the temperature is above 1000℃. The heating rate is 10℃ / min~30℃ / min, and the cooling rate is 10℃ / min~30℃ / min. Other steps are the same as in Specific Implementation Methods One to Five.

[0034] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that the sintering described in step three is discharge plasma sintering. The other steps are the same as in Specific Implementation Methods One through Six.

[0035] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the discharge plasma sintering process is as follows: The temperature is raised from room temperature to 1600℃~2200℃, held at 1600℃~2200℃ for 1min~60min, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 20MPa~100MPa when the temperature is above 1000℃. The heating rate is 20℃ / min~150℃ / min, and the cooling rate is 20℃ / min~150℃ / min. Other steps are the same as in Specific Implementation Methods One to Seven.

[0036] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the inert gas mentioned in step three is argon, helium, or krypton. The other steps are the same as in Specific Implementation Methods One to Eight.

[0037] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the sintering described in step three is a multi-step hot-pressing sintering process. The multi-step hot-pressing sintering process is as follows: The temperature is raised from room temperature to 1000℃~1600℃, held at 1000℃~1600℃ for 10min~120min, then further raised to 1600℃~2200℃, held at 1600℃~2200℃ for 30min~300min. During the sintering process, when the temperature is below 1000℃, the pressure is maintained at 10MPa; when the temperature is above 1000℃, the pressure is maintained at 20MPa~100MPa. The heating rate is 10℃ / min~30℃ / min, and the cooling rate is 10℃ / min~30℃ / min. Other steps are the same as in Specific Implementation Methods One to Nine.

[0038] The beneficial effects of the present invention are verified using the following embodiments:

[0039] Example 1: A method for preparing a novel tungsten-based composite material (5Gd5Hf) for high-energy gamma ray shielding, comprising the following steps:

[0040] I. Weighing materials:

[0041] Weigh out tungsten powder, gadolinium powder, and hafnium powder to obtain the raw materials;

[0042] The raw materials mentioned in step one contain 5% gadolinium powder by mass and 5% hafnium powder by mass.

[0043] II. Powder Mixing:

[0044] After the tungsten powder, gadolinium powder and hafnium powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0045] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0046] III. Sintering:

[0047] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd5Hf) for high-energy gamma ray shielding.

[0048] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0049] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 1 exhibits uniform elemental distribution, a density of 99.19%, a hardness of 4.29 GPa, and a flexural strength of 470 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 52.2%, which is equivalent to 1.47 times the shielding capacity of Pb of the same thickness.

[0050] Example 2: A method for preparing a novel tungsten-based composite material (5Gd8Hf) for high-energy gamma ray shielding, comprising the following steps:

[0051] I. Weighing materials:

[0052] Weigh out tungsten powder, gadolinium powder, and hafnium powder to obtain the raw materials;

[0053] The raw materials mentioned in step one contain 5% gadolinium powder by mass and 8% hafnium powder by mass.

[0054] II. Powder Mixing:

[0055] After the tungsten powder, gadolinium powder and hafnium powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0056] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0057] III. Sintering:

[0058] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd8Hf) for high-energy gamma ray shielding.

[0059] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0060] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 2 exhibits uniform elemental distribution, a density of 99.33%, a hardness of 4.45 GPa, and a flexural strength of 569 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 51.9%, which is equivalent to 1.45 times the shielding capacity of Pb of the same thickness.

[0061] Example 3: A method for preparing a novel tungsten-based composite material (5Gd10Hf) for high-energy gamma ray shielding, comprising the following steps:

[0062] I. Weighing materials:

[0063] Weigh out tungsten powder, gadolinium powder, and hafnium powder to obtain the raw materials;

[0064] In step one, the raw materials contain 5% gadolinium powder and 10% hafnium powder by mass.

[0065] II. Powder Mixing:

[0066] After the tungsten powder, gadolinium powder and hafnium powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0067] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0068] III. Sintering:

[0069] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd10Hf) for high-energy gamma ray shielding.

[0070] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0071] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 3 exhibits uniform elemental distribution, a density of 99.77%, a hardness of 4.25 GPa, and a flexural strength of 578 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 51.6%, which is equivalent to 1.43 times the shielding capacity of Pb of the same thickness.

[0072] Example 4: A method for preparing a novel tungsten-based composite material (5Gd15Hf) for high-energy gamma ray shielding, comprising the following steps:

[0073] I. Weighing materials:

[0074] Weigh out tungsten powder, gadolinium powder, and hafnium powder to obtain the raw materials;

[0075] The raw materials mentioned in step one contain 5% gadolinium powder by mass and 15% hafnium powder by mass.

[0076] II. Powder Mixing:

[0077] After the tungsten powder, gadolinium powder and hafnium powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0078] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0079] III. Sintering:

[0080] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd15Hf) for high-energy gamma ray shielding.

[0081] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0082] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 4 exhibits uniform elemental distribution, a density of 98.92%, a hardness of 5.52 GPa, and a flexural strength of 593 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 50.6%, which is equivalent to 1.40 times the shielding capacity of Pb of the same thickness.

[0083] Example 5: A method for preparing a novel tungsten-based composite material (2Gd2O3) for high-energy gamma ray shielding, comprising the following steps:

[0084] I. Weighing materials:

[0085] Weigh out tungsten powder and gadolinium oxide powder to obtain the raw materials;

[0086] The mass fraction of gadolinium oxide powder in the raw materials mentioned in step one is 2%;

[0087] II. Powder Mixing:

[0088] After the tungsten powder and gadolinium oxide powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0089] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 10:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0090] III. Sintering:

[0091] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (2Gd2O3) for high-energy gamma ray shielding.

[0092] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1800℃, held at 1800℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0093] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 5 exhibits uniform elemental distribution, a density of 99.03%, a hardness of 5.22 GPa, and a flexural strength of 802 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 53.7%, which is equivalent to 1.52 times the shielding capacity of Pb of the same thickness.

[0094] Example 6: A method for preparing a novel tungsten-based composite material (4Gd2O3) for high-energy gamma ray shielding, comprising the following steps:

[0095] I. Weighing materials:

[0096] Weigh out tungsten powder and gadolinium oxide powder to obtain the raw materials;

[0097] The mass fraction of gadolinium oxide powder in the raw materials mentioned in step one is 4%;

[0098] II. Powder Mixing:

[0099] After the tungsten powder and gadolinium oxide powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0100] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 10:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0101] III. Sintering:

[0102] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (4Gd2O3) for high-energy gamma ray shielding.

[0103] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1800℃, held at 1800℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0104] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 6 exhibits uniform elemental distribution, a density of 98.94%, a hardness of 6.93 GPa, and a flexural strength of 924 MPa. At a thickness of 10 mm, the material provides excellent performance in [various applications]. 60 The Co source shielding rate is 52.8%, which is equivalent to 1.49 times the shielding capacity of Pb of the same thickness.

[0105] Example 7: A method for preparing a novel tungsten-based composite material (6Gd2O3) for high-energy gamma ray shielding, comprising the following steps:

[0106] I. Weighing materials:

[0107] Weigh out tungsten powder and gadolinium oxide powder to obtain the raw materials;

[0108] The mass fraction of gadolinium oxide powder in the raw materials mentioned in step one is 6%;

[0109] II. Powder Mixing:

[0110] After the tungsten powder and gadolinium oxide powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0111] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 10:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0112] III. Sintering:

[0113] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (6Gd2O3) for high-energy gamma ray shielding.

[0114] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1800℃, held at 1800℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0115] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 7 exhibits uniform elemental distribution, a density of 99.34%, a hardness of 7.11 GPa, and a flexural strength of 966 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 52.0%, which is equivalent to 1.45 times the shielding capacity of Pb of the same thickness.

[0116] Example 8: A method for preparing a novel tungsten-based composite material (14Gd2O3) for high-energy gamma ray shielding, comprising the following steps:

[0117] I. Weighing materials:

[0118] Weigh out tungsten powder and gadolinium oxide powder to obtain the raw materials;

[0119] The mass fraction of gadolinium oxide powder in the raw materials mentioned in step one is 14%;

[0120] II. Powder Mixing:

[0121] After the tungsten powder and gadolinium oxide powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0122] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 10:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0123] III. Sintering:

[0124] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (14Gd2O3) for high-energy gamma ray shielding.

[0125] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1800℃, held at 1800℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0126] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 8 exhibits uniform elemental distribution, a density of 98.82%, a hardness of 7.17 GPa, and a flexural strength of 1015 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 51.5%, which is equivalent to 1.44 times the shielding capacity of Pb of the same thickness.

[0127] Example 9: A method for preparing a novel tungsten-based composite material (5Gd10HfB2) for high-energy gamma ray shielding, comprising the following steps:

[0128] I. Weighing materials:

[0129] Weigh out tungsten powder, gadolinium powder, and hafnium diboride powder to obtain the raw materials;

[0130] The raw materials mentioned in step one contain 5% gadolinium powder and 10% hafnium diboride powder by mass.

[0131] II. Powder Mixing:

[0132] After the tungsten powder, gadolinium powder and hafnium diboride powder weighed in step one are initially mixed, they are then ball-milled in a vacuum environment to achieve a thorough and uniform mixing of the powders. The mixture is then sieved through an 80-mesh sieve in an argon atmosphere to obtain a uniformly mixed raw material.

[0133] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0134] III. Sintering:

[0135] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd10HfB2) for high-energy gamma ray shielding.

[0136] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0137] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 9 exhibits uniform elemental distribution, a density of 98.26%, a hardness of 7.54 GPa, and a flexural strength of 375 MPa. At a thickness of 10 mm, the material provides excellent performance against... 60 The Co source shielding rate is 48.8%, which is equivalent to 1.33 times the shielding capacity of Pb of the same thickness.

[0138] Example 10: A method for preparing a novel tungsten-based composite material (5Gd20HfB2) for high-energy gamma ray shielding, comprising the following steps:

[0139] I. Weighing materials:

[0140] Weigh out tungsten powder, gadolinium powder, and hafnium diboride powder to obtain the raw materials;

[0141] The raw materials mentioned in step one contain 5% gadolinium powder and 20% hafnium diboride powder by mass.

[0142] II. Powder Mixing:

[0143] After the tungsten powder, gadolinium powder and hafnium diboride powder weighed in step one are initially mixed, they are then ball-milled in a vacuum environment to achieve a thorough and uniform mixing of the powders. The mixture is then sieved through an 80-mesh sieve in an argon atmosphere to obtain a uniformly mixed raw material.

[0144] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0145] III. Sintering:

[0146] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (5Gd20HfB2) for high-energy gamma ray shielding.

[0147] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0148] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 10 has a uniform elemental distribution, a density of 98.38%, a hardness of 11.66 GPa, and a flexural strength of 400 MPa. The material, at a thickness of 10 mm, exhibits excellent performance in shielding against high-energy gamma rays. 60 The Co source shielding rate is 46.2%, which is equivalent to 1.23 times the shielding capacity of Pb of the same thickness.

[0149] Example 11: A method for preparing a novel tungsten-based composite material (0.5Gd₂O₃0.5HfO₂) for high-energy gamma ray shielding, comprising the following steps:

[0150] I. Weighing materials:

[0151] Weigh out tungsten powder, gadolinium oxide powder, and hafnium oxide powder to obtain the raw materials;

[0152] The raw materials mentioned in step one contain 0.5% gadolinium oxide powder and 0.5% hafnium oxide powder by mass.

[0153] II. Powder Mixing:

[0154] After the tungsten powder, gadolinium oxide powder and hafnium oxide powder weighed in step one are initially mixed, they are ball-milled in a vacuum environment to achieve full and uniform mixing of the powders. The mixture is then sieved in an argon atmosphere through an 80-mesh sieve to obtain a uniformly mixed raw material.

[0155] The ball milling process described in step two is as follows: an all-around planetary ball mill is used, the ball-to-material ratio is 5:1, the speed of the ball mill is 200 r / min, the milling time is 24 h, and the material of the grinding jar and the grinding balls is hard alloy.

[0156] III. Sintering:

[0157] The uniformly mixed raw materials obtained in step two are placed in a graphite mold and hot-pressed and sintered in an argon atmosphere to obtain a novel tungsten-based composite material (0.5Gd2O30.5HfO2) for high-energy gamma ray shielding.

[0158] The hot pressing sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 60 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0159] The novel tungsten-based composite material for high-energy gamma ray shielding prepared in Example 11 has a uniform elemental distribution, a density of 99.21%, a room temperature hardness of 4.6 GPa, and a flexural strength of 750 MPa. The material, at a thickness of 10 mm, exhibits excellent performance in [various applications]. 60 The Co source shielding rate is 55.1%, which is equivalent to 1.59 times the shielding capacity of Pb of the same thickness.

[0160] Comparative Example 1: The preparation method of pure tungsten material is carried out according to the following steps:

[0161] 1. Weigh the required powder:

[0162] Weigh out tungsten powder to obtain the raw material;

[0163] II. Mixing the initial powder:

[0164] The tungsten powder weighed in step one is subjected to all-round planetary ball milling in a vacuum environment and then sieved in an argon atmosphere through an 80-mesh sieve.

[0165] The high-energy ball milling process parameters described in step two are: ball-to-material ratio of 5:1, ball mill speed of 200 r / min, and ball milling time of 24 h.

[0166] III. Sintering:

[0167] The powder obtained in step two is placed in a graphite mold and hot-pressed and sintered under argon protection to obtain the corresponding pure tungsten material, namely W.

[0168] The sintering process described in step three is as follows: the temperature is raised from room temperature to 1900℃, held at 1900℃ for 10 minutes, and then cooled to room temperature. During the sintering process, the pressure is maintained at 10MPa when the temperature is below 1000℃ and at 30MPa when the temperature is above 1000℃. The heating rate is 20℃ / min and the cooling rate is 20℃ / min.

[0169] The pure tungsten material prepared in Comparative Example 1 had a density of 99.82%, a hardness of 3.49 GPa, and a flexural strength of 462 MPa. The material, at a thickness of 10 mm, exhibited [specific properties related to tungsten]. 60 The Co source shielding rate is 55.6%, which is equivalent to 1.61 times the shielding capacity of Pb of the same thickness.

[0170] Figure 1SEM images of novel tungsten-based composite materials for high-energy gamma ray shielding with different mass fractions prepared for the examples are shown in the figures. (a) is 5Gd5Hf prepared in Example 1, (b) is 5Gd8Hf prepared in Example 4, (c) is 4Gd2O3 prepared in Example 6, (d) is 6Gd2O3 prepared in Example 7, (e) is 5Gd10HfB2 prepared in Example 9, and (f) is 5Gd20HfB2 prepared in Example 9.

[0171] from Figure 1 It can be seen that the novel tungsten-based composite material (5Gd5Hf) for high-energy gamma ray shielding prepared in Example 1 has high density, uniform distribution of the second phase, and no obvious segregation.

Claims

1. A method for producing a novel tungsten-based composite material for high-energy gamma-ray shielding, characterized by The preparation method comprises the following steps: I. weighing materials: weighing tungsten powder and modified powder to obtain raw materials; the modified powder is one or a mixture of several of gadolinium powder, gadolinium oxide powder, gadolinium boride powder, gadolinium carbide powder, hafnium powder, hafnium oxide powder, hafnium boride powder, and hafnium carbide powder; II. mixing the powder: after the tungsten powder and the modified powder are preliminarily mixed, they are mixed in all directions in an inert gas or vacuum environment, and sieved in an inert gas environment to obtain a uniformly mixed composite powder raw material; III. sintering: the composite powder raw material is placed in a graphite mold and sintered in an inert gas or vacuum environment to obtain a new tungsten-based composite material for high-energy gamma ray shielding.

2. The method of claim 1, wherein the method is characterized by In step I, the mass fraction of the modified powder in the raw material is 0.1% to 30%.

3. The method of claim 1, wherein the method is characterized by In step II, the ball milling process is as follows: a full-direction planetary ball mill is used, the ball-to-material ratio is (5-20):1, the rotation speed of the ball mill is 50 r / min to 500 r / min, the ball milling time is 12 h to 48 h, and the ball mill tank and the grinding balls are made of hard alloy.

4. The method of claim 1, wherein the method is characterized by In step II, the inert gas is argon, helium, or krypton; and the sieving is 80 mesh to 320 mesh.

5. The method of claim 1, wherein the method is characterized by In step III, the sintering is hot-press sintering.

6. The method of claim 1, wherein the method is characterized by The hot-press sintering process is as follows: the temperature is raised from room temperature to 1600°C to 2200°C, the temperature is kept at 1600°C to 2200°C for 10 min to 120 min, and then the temperature is lowered to room temperature; the pressure is kept at 10 MPa when the temperature is lower than 1000°C, and the pressure is kept at 20 MPa to 100 MPa when the temperature is higher than 1000°C; the temperature rising rate is 10°C / min to 30°C / min, and the temperature lowering rate is 10°C / min to 30°C / min.

7. The method of claim 1, wherein the method is characterized by In step III, the sintering is spark plasma sintering.

8. The method of claim 1, wherein the method is characterized by The spark plasma sintering process is as follows: the temperature is raised from room temperature to 1600°C to 2200°C, the temperature is kept at 1600°C to 2200°C for 1 min to 60 min, and then the temperature is lowered to room temperature; the pressure is kept at 10 MPa when the temperature is lower than 1000°C, and the pressure is kept at 20 MPa to 100 MPa when the temperature is higher than 1000°C; the temperature rising rate is 20°C / min to 150°C / min, and the temperature lowering rate is 20°C / min to 150°C / min.

9. The method of claim 1, wherein the method is characterized by In step III, the inert gas is argon, helium, or krypton.

10. The method of claim 1, wherein the method is characterized by In step III, the sintering is multi-step hot-press sintering; the multi-step hot-press sintering process is as follows: the temperature is raised from room temperature to 1000°C to 1600°C, the temperature is kept at 1000°C to 1600°C for 10 min to 120 min, then the temperature is continuously raised to 1600°C to 2200°C, the temperature is kept at 1600°C to 2200°C for 30 min to 300 min, the pressure is kept at 10 MPa when the temperature is lower than 1000°C, and the pressure is kept at 20 MPa to 100 MPa when the temperature is higher than 1000°C; the temperature rising rate is 10°C / min to 30°C / min, and the temperature lowering rate is 10°C / min to 30°C / min.

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