A method for increasing the content of high-quality phases in beryllium alloys

Abstract

This invention relates to a method for increasing the content of high-quality phases in beryllium alloys, belonging to the field of beryllium alloy preparation technology, and is used to solve the problem of low high-quality phase content in beryllium alloys prepared by existing methods. The method of this invention includes: weighing beryllium powder and X powder according to an atomic ratio of Be to X of 12.1~13.3:1, wherein X is at least one of Ti, W, V, or Zr; pre-treating the mixed powder of beryllium powder and X powder by ball milling; annealing the pre-treated mixed powder; mixing and granulating the annealed mixed powder with a binder to obtain a feedstock; preparing a green blank using injection molding; removing the binder from the green blank using a debinding process to obtain a raw blank; sintering the raw blank under a protective atmosphere at a sintering temperature of 845~1185℃ for 4~6 hours; cooling the sintered body to below 250℃ using ultra-rapid cooling after holding; and performing low-temperature annealing on the cooled material to obtain a beryllium alloy with a high content of high-quality phases. The method of this invention can obtain beryllium alloys with a high content of high-quality phases.

Description

Technical Field

[0001] This invention relates to the field of beryllium alloy preparation technology, and in particular to a method for increasing the content of high-quality phases in beryllium alloys. Background Technology

[0002] Deuterium-tritium fusion requires the proliferation of tritium fuel using neutron multipliers to address the "tritium self-sufficiency" problem. Currently, controlled nuclear fusion gas-cooled reactors use pure beryllium microspheres as neutron multipliers. However, beryllium microspheres are prone to helium embrittlement and swelling under high-energy neutron irradiation, affecting the safety and service life of the fusion reactor. Beryllium alloy microspheres have become the preferred material to replace beryllium microspheres. However, after replacing beryllium microspheres with beryllium alloy microspheres, the neutron yield decreases due to the reduced beryllium content. Therefore, beryllium alloy microspheres with a high beryllium content (Be) are necessary. 12 X and / or Be 13 The preparation of a high-quality X phase (X can be one of Ti, W, V, or Cr) is key to achieving efficient neutron multiplication and thus effective tritium self-sustaining.

[0003] The rotating electrode method is currently the mainstream method for preparing beryllium alloy microspheres. However, the preparation conditions of the rotating electrode method are complex, and the yield per batch is low, resulting in low efficiency. When other existing processes are used to prepare beryllium alloy microspheres, the content of high-quality phases is low, and the beryllium content is also low. Therefore, how to provide a method for efficiently preparing beryllium alloys with high content of high-quality phases has become an urgent problem to be solved. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a method for increasing the content of high-quality phases in beryllium alloys, thereby solving one of the problems of low efficiency in the preparation of beryllium alloys and low content of high-quality phases in beryllium alloys in existing methods.

[0005] On one hand, embodiments of the present invention provide a method for increasing the content of high-quality phases in beryllium alloys, comprising the following steps: Step 1: Weigh beryllium powder and X powder precisely according to the atomic ratio of Be to X of 12.1~13.3:1, wherein X is at least one of Ti, W, V or Zr; Step 2: Pre-treat the mixture of beryllium powder and X powder by ball milling; Step 3: Anneal the pretreated mixed powder; Step 4: The annealed mixed powder and binder are kneaded and granulated to obtain the feed; Step 5: Prepare green blanks using injection molding process; Step 6: Remove the binder from the green body through a degreasing process to obtain the raw green body; Step 7: Sinter the green body under a protective atmosphere at a temperature of 845~1185℃ for 4~6 hours; after holding, use ultra-fast cooling to cool the sintered body to below 250℃. Step 8: Perform low-temperature annealing on the cooled material to obtain a beryllium alloy with high quality phase content.

[0006] Furthermore, in step 2, the ball-to-material ratio is 2~3:1.

[0007] Furthermore, in step 2, the ball milling speed is 600~800 rpm, and the ball milling time is 5~8 hours.

[0008] Furthermore, in step 3, the annealing process includes the following steps: the mixed powder is loaded into a vacuum heat treatment furnace, held at 800~1000℃ for 1~10h, and then cooled to room temperature.

[0009] Furthermore, in step 4, the adhesive components include polyoxymethylene and acrylonitrile. butadiene Styrene copolymers, polyethylene, ethylene-vinyl acetate copolymers, stearic acid, paraffin wax, polyethyleneimine, triethanolamine, and BASF antioxidants.

[0010] Furthermore, in step 4, the mass ratio of the binder to the mixed powder is controlled to be 27~32:68~73.

[0011] Furthermore, in step 7, sintering includes the following steps: S701. Place the green billet in a high-temperature furnace under a protective atmosphere and heat it to 845~855℃ and hold it thereafter. S702, heat to 1000~1185℃ and hold; S703. After the heat preservation is completed, ultra-fast cooling is used to rapidly cool the sintered body to below 250 ℃.

[0012] Furthermore, in the S703, the ultra-fast cooling rate is above 42°C / min.

[0013] Furthermore, in step 8, the holding temperature for the annealing treatment is 300~600℃.

[0014] The present invention also provides a beryllium alloy with high content of high-quality phase, which is prepared by the above-described method.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: The method of this invention, through strict composition control, pretreatment of mixed powder ball milling + annealing, segmented precise temperature-controlled sintering, ultra-fast cooling, and subsequent low-temperature annealing, ensures the production of beryllium alloys with high-quality phase content. It also significantly improves the microstructure uniformity and density of the beryllium alloys, effectively avoiding defects such as internal stress and cracks that may occur during ultra-fast cooling. This results in beryllium alloys with superior mechanical properties and structural stability, enabling them to maintain good performance under the harsh operating environment of fusion reactors and extend their service life.

[0016] The beryllium alloy prepared by the method of this invention has a relative density of over 95%, and the Be in the beryllium alloy... 12 X and / or Be 13 The X phase has a mass percentage of over 98%, making this ultra-high purity Be. 12 X and / or Be 13 The superior X phase endows beryllium alloys with excellent neutron multiplication properties, which can effectively compensate for the loss of neutron yield caused by the reduction of beryllium content, thereby better meeting the urgent need for high-efficiency neutron multiplication materials and providing material support for achieving "tritium self-sufficiency".

[0017] The beryllium alloy prepared by the method of the present invention has excellent mechanical properties, such as a room temperature compressive strength of more than 1800 MPa, for example, 1800~2700 MPa.

[0018] The method of this invention has the advantages of high process controllability and good repeatability. By precisely controlling key parameters such as raw material ratio, ball mill pretreatment, sintering temperature, holding time, cooling rate and annealing process, beryllium alloys with high quality phase content can be stably prepared, which is conducive to realizing industrial production.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the specific points highlighted in the description. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 Here is a SEM image of the beryllium titanium microspheres from Example 1; Figure 2 The image shows the XRD pattern of the beryllium titanium microspheres from Example 1. Detailed Implementation

[0022] The preferred embodiments of the present invention are described in detail below. These embodiments are used to illustrate the principles of the present invention and are not intended to limit the scope of the present invention.

[0023] Currently, beryllium alloy systems used as neutron multipliers mainly include beryllium titanium, beryllium tungsten, beryllium vanadium, and beryllium zirconium. These beryllium alloy systems contain various intermetallic compound phases, such as Be. 12 X, Be 13 X, Be 17 X2, etc., where X can be Ti, W, V, Zr; the formation conditions and stability of various intermetallic compound phases differ, and how to precisely control process parameters to promote Be 12 X, Be 13 Phase X (the superior phase) is preferentially and abundantly formed, while other non-target phases (such as Be) are suppressed. 17 The precipitation of X2 phase and pure Be phase is essential for achieving high-purity Be. 12 X, Be 13 The challenges of the X phase. How to achieve high Be 12 X, Be 13 Ensuring the uniformity and density of the microstructure of beryllium alloys, as well as their good mechanical and neutronic properties, while avoiding defects such as cracks, is a technical challenge that needs to be overcome.

[0024] This invention provides a method for increasing the content of high-quality phases in beryllium alloys, comprising the following steps: Step 1: Weigh beryllium powder and X powder precisely according to the atomic ratio of Be to X of 12.1:1 to 13.3:1, wherein X is at least one of Ti, W, V, and Zr; Step 2: Pre-treat the mixture of beryllium powder and X powder by ball milling; Step 3: Anneal the pretreated mixed powder; Step 4: The annealed mixed powder and binder are kneaded and granulated to obtain the feed; Step 5: Prepare green blanks using injection molding process; Step 6: Remove the binder from the green body through a degreasing process to obtain the raw green body; Step 7: Sinter the green body under a protective atmosphere at a temperature of 850~1150℃ for 4~6 hours. After holding, use ultra-fast cooling to cool the sintered body to below 250℃. Step 8: Perform low-temperature annealing on the cooled material to obtain a beryllium alloy with high quality phase content.

[0025] Specifically, in step 1 above, considering that if the beryllium content is too low, the volatilization loss of beryllium during the subsequent high-temperature process can easily lead to a beryllium-depleted phase (Be). 17 X 2、 Be10 The generation of (X, Be3X, Be2X, etc.) leads to Be 12 X, Be 13 The content of high-quality X phase decreases; however, the addition of excessive beryllium will result in sintered beryllium alloys rich in pure beryllium phase, which can lead to beryllium-water reaction in fusion environments, posing a safety hazard to fusion reactors. Therefore, balancing the ratio of Be to X is crucial for obtaining high Be content. 12 X, Be 13 X is a prerequisite for high-quality phase and low-beryllium phase. Based on the heat treatment and sintering temperatures, the volatilization rate of beryllium is calculated to ensure it remains within the Be... 12 X, Be 13 Based on the stoichiometric ratio of the thermodynamic formation conditions, a surplus of beryllium is added, placing the entire mixed powder system in a state of trace beryllium enrichment, thus providing a basis for Be. 12 X, Be 13 The formation of phase X provides optimal compositional conditions, reducing the occurrence of other non-target phases (Be) due to compositional segregation. 17 X 2、 Be 10 The generation of (X, Be3X, Be2X, etc.) is controlled. Therefore, the atomic ratio of Be to X is controlled to be 12.1:1 to 13.3:1, for example 12.1:1, 12.2:1, 12.3:1, 13.1:1, 13.2:1, 13.3:1.

[0026] Specifically, in step 1 above, when X is Ti, W, or V, the atomic ratio of Be to X is controlled to be 12.1:1 to 12.3:1; when X is Zr, the atomic ratio of Be to X is controlled to be 13.1:1 to 13.3:1.

[0027] Specifically, in step 2 above, the high-energy ball milling pretreatment can refine the powder and promote the initial diffusion of elements.

[0028] Specifically, in step 2 above, the high-energy ball milling pretreatment can be carried out in a high-energy planetary ball mill, using a cemented carbide grinding jar and grinding balls.

[0029] Specifically, in step 2 above, considering that an excessively high ball-to-material mass ratio will lead to a low yield, and an excessively low ball-to-material mass ratio will lead to insufficient mixing and alloying, the ball-to-material mass ratio is controlled to be 2~3:1, for example 2:1, 2.5:1, or 3:1.

[0030] Specifically, in step 2 above, considering that excessive ball milling speed can lead to excessive cold welding and agglomeration of powder, affecting the uniformity of subsequent mixing; while insufficient speed cannot provide enough mechanical energy to achieve effective powder refinement and element diffusion; excessively long ball milling time can lead to severe powder oxidation and increased energy consumption; and excessively short ball milling time can make it difficult to achieve the ideal refinement and diffusion effect, the ball milling speed is controlled at 600~800 rpm, the ball milling time is 5~8 hours, and the ball milling atmosphere is argon. For example, the ball milling speeds are 600 rpm, 650 rpm, 700 rpm, 750 rpm, and 800 rpm; and the ball milling times are 5 hours, 6 hours, 7 hours, and 8 hours.

[0031] Specifically, in step 3 above, the annealing process includes the following steps: The mixed powder is placed in a vacuum heat treatment furnace and kept at 800~1000℃ for 1~10 hours, then cooled to room temperature.

[0032] It should be noted that the purpose of annealing in step 3 above is to... 12 X and / or Be 13 The nucleation and growth of the X phase provides more active sites, thereby increasing Be 12 X and / or Be 13 The nucleation rate and growth driving force of the X phase inhibit the competitive nucleation of non-target phases. Considering that excessively high holding temperatures and long holding times can lead to powder caking, while excessively low holding temperatures and short holding times can result in incomplete powder pre-alloying, the holding temperature is controlled at 800~1000℃ for 1~10h. For example, holding temperatures are 800℃, 850℃, 900℃, 950℃, and 1000℃; holding times are 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, and 10h.

[0033] Specifically, in step 3, the cooling method is not limited; it can be rapid cooling or cooling with the furnace.

[0034] Specifically, in step 4, the adhesive components include polyoxymethylene and acrylonitrile. butadiene The binder contains styrene copolymer, high-density polyethylene, ethylene-vinyl acetate copolymer, stearic acid, paraffin wax, polyethyleneimine, triethanolamine, and BASF antioxidants. The binder employing these components provides support for the preform skeleton, powder lubrication and bonding, and powder oxidation resistance.

[0035] Specifically, the polyethylene used is high-density polyethylene, with a density range of 0.941~0.965 g / cm³. 3 .

[0036] Specifically, in step 4, considering polyoxymethylene and acrylonitrile butadiene Excessive mass of styrene copolymer results in a low green body density, making densification difficult during sintering. (Polyoxymethylene and acrylonitrile) butadiene Insufficient styrene copolymer content results in insufficient mechanical strength of the green body, making it prone to breakage. Stearic acid, as a powder surfactant, reduces interfacial tension, improves wettability, and lowers viscosity. Paraffin wax, as the main binder, provides low-temperature fluidity and establishes degreasing channels. Polyethyleneimine, as a coupling agent, creates chemical bonds between the powder and the binder, preventing phase separation. Triethanolamine, as a dispersant, prevents powder agglomeration and stabilizes the slurry system. High-density polyethylene, as a key component of the binder, primarily encapsulates the powder and provides fluidity after heating and melting for injection molding, and solidifies upon cooling to maintain the shape and strength of the green body. Ethylene-vinyl acetate copolymer improves the flexibility and adhesion of the feedstock and helps maintain shape during degreasing. BASF antioxidants prevent oxidation of the metal powder. Excessive addition of these additives affects sintering densification; insufficient addition fails to achieve the desired effect. Therefore, the mass percentages of each component in the binder are controlled as follows: polyoxymethylene 62-82%, acrylonitrile... butadiene Styrene copolymer 4-6%, high-density polyethylene 4-6%, ethylene-vinyl acetate copolymer 3-5%, stearic acid 2-4%, paraffin wax 3-5%, polyethyleneimine 2-4%, triethanolamine 1-3%, BASF antioxidant 1-3%.

[0037] Specifically, BASF uses BASF Antioxidant 1010 as its antioxidant.

[0038] Specifically, in step 4, the mass ratio of the binder to the mixed powder is controlled to be 27~32:68~73.

[0039] Specifically, in step 4, the mixing process is carried out under a protective atmosphere filled with argon. Considering that excessively high temperatures can lead to polymerization of the binder, while excessively low temperatures result in poor wetting and flowability, excessively high rotation speeds can cause excessive shear force, leading to separation of the powder and binder and breakage of powder particles. Insufficient rotation speeds result in low shear rates, uneven mixing, and high viscosity, leading to excessively long mixing times. Therefore, the mixing process is controlled at a temperature of 175-185℃ and a rotation speed of 35-45 rpm for 55-65 minutes. This allows the organic components to fully melt and uniformly coat the powder particles, forming a uniform feed agglomerate, laying the foundation for uniform phase transformation in subsequent forming, debinding, and sintering processes. For example, temperatures of 175℃, 180℃, and 185℃; rotation speeds of 35 rpm, 40 rpm, and 45 rpm; and mixing times of 55 minutes, 60 minutes, and 65 minutes.

[0040] Specifically, in step 4, the feed agglomerate is granulated using a twin-screw extruder. The screw temperature is controlled in zones as follows: the temperature of the feeding section is the same as that of the mixing section, while the temperature of the discharge section is higher than that of the feeding section. Specifically, the temperatures of the feeding and mixing sections are 165~173℃, for example, 165℃, 170℃, and 173℃; the temperature of the discharge section is 175~183℃, for example, 175℃, 180℃, and 183℃. The extruded strip material is then air-cooled and granulated to obtain granular feedstock with uniform particle size suitable for injection molding.

[0041] Specifically, in step 4, the particle size of the granular feed is approximately 1.7~2.3 mm.

[0042] Specifically, in step 5, the feed material is injected into the mold cavity using injection molding equipment to form a green blank that is similar in size and shape to the target beryllium alloy.

[0043] Specifically, in step 5, the mold design needs to take into account the shrinkage rate during the subsequent degreasing and sintering processes to ensure the dimensional accuracy of the final product.

[0044] Specifically, in step 5, the injection process adopts zoned precise temperature control. The barrel temperature is set sequentially from the feeding section to the nozzle as 150~155℃, 150~155℃, 161~163℃, 165~168℃, and 170~173℃ to ensure that the feed gradually plasticizes, homogenizes, and maintains good rheological properties during the feeding process.

[0045] Specifically, in step 5, the mold temperature is kept constant at 75~80℃. The injection process uses two-stage pressure control: first, a higher injection pressure of 106~113MPa is used to achieve rapid filling of the cavity by the melt, then the injection pressure is switched to 93~97MPa to complete stable filling and initial shrinkage, and then the holding pressure of 47~53MPa is applied for 4~7 seconds to ensure that the preform is dense and dimensionally accurate.

[0046] Specifically, in step 6, the degreasing process includes two steps: catalytic degreasing and thermal degreasing. The catalytic degreasing temperature is 125~130℃, and the temperature is maintained for 8~10 hours. After catalytic degreasing, thermal degreasing is carried out. The thermal degreasing temperature is increased by 2~5℃ / min, and the temperature is maintained in stages in the range of 400-800℃.

[0047] Specifically, in step 6, catalytic degreasing includes the following steps: placing the green body in a degreasing furnace filled with oxalic acid vapor generated by the sublimation of solid oxalic acid crystals, and holding it at 125~130 ℃ for 8~10 h. During this process, the oxalic acid vapor acts as a catalyst, causing the binder, polyoxymethylene, to undergo a depolymerization reaction and be discharged, efficiently and safely removing polyoxymethylene while maintaining the shape of the green body, thus forming preliminary pore channels.

[0048] Specifically, in step 6, thermal defatting includes the following steps: S601. Transfer the billet to a vacuum degassing furnace and heat it to 395-405℃ (e.g., 395℃, 400℃, 405℃) at a rate of 2-5℃ / min (e.g., 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min), and hold it for 0.9-1.1h (0.9h, 1h, 1.1h) to fully remove low-boiling-point components from the binder; S602. Continue heating to 595~605℃ (e.g., 595℃, 600℃, 605℃), hold for 0.9~1.1h (e.g., 0.9h, 1h, 1.1h), continue heating to 795~805℃ (e.g., 795℃, 800℃, 805℃), hold for 0.9~2.1h (e.g., 0.9h, 1h, 1.5h, 2h, 2.1h) to allow the high-boiling-point components to completely decompose and be discharged, ultimately obtaining a clean, crack-free green body suitable for subsequent sintering.

[0049] Specifically, in step 7, sintering includes the following steps: S701. Place the green billet in a high-temperature furnace protected by high-purity argon gas, and heat it to 845~855℃ (e.g., 845℃, 850℃, 855℃) at a rate of 3~5℃ / min, and hold it at that temperature for 0.9~1.1h (e.g., 0.9h, 1h, 1.1h). The purpose of this step is to perform low-temperature pre-firing and purification. S702, heat to 1000-1185℃ (e.g., 1145℃, 1150℃, 1155℃) at a rate of 3-5℃ / min, and hold for 3-6 hours (e.g., 3 hours, 4 hours, 5 hours); the purpose of this step is to allow beryllium and X atoms to diffuse fully and react to synthesize the target Be. 12 X and / or Be 13 X phase, simultaneously achieving material densification; S703. Immediately after the heat treatment, ultra-rapid cooling is employed to rapidly cool the sintered body to below 250 °C. This step suppresses beryllium volatilization, thereby preventing the formation of the non-target phase (Be). 17 X 2、 Be 10 Transformation of (X, Be3X, Be2X, etc.).

[0050] Specifically, in S703, ultra-fast cooling is achieved by high-pressure argon gas rapid cooling, with a cooling rate of 42℃ / min or higher, for example, 42~60℃ / min, such as 42℃ / min, 45℃ / min, 50℃ / min, 55℃ / min, and 60℃ / min.

[0051] Specifically, in step 7, during the sintering process, the holding temperature, holding time, and cooling rate have a significant impact on the phase transformation kinetics and phase composition. If the temperature is not properly controlled, it may lead to uneven element diffusion, making it difficult to form a uniform Be phase. 12 X and / or Be 13 X phase; insufficient holding time will result in incomplete reaction, while excessive holding time may lead to grain coarsening or secondary phase precipitation; the purpose of ultra-rapid cooling is to maintain high temperature for Be formation. 12 X and / or Be 13 X phase, to prevent Be 12 X and / or Be 13 Phase X decomposes or transforms into other thermodynamically more stable but non-target phases during slow cooling. Precise control of these steps ensures a high content of high-quality phases.

[0052] Specifically, in step 8, the annealing process is carried out under a high-purity argon atmosphere.

[0053] Specifically, in step 8, the annealing process is as follows: the material is heated to 300-600 °C at a rate of 3~8°C / min (3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min), held at that temperature for 1~2 hours, and then cooled to room temperature in the furnace.

[0054] Specifically, in step 8, in order to minimize the internal residual stress generated by ultra-rapid cooling during sintering and further stabilize the microstructure of the beryllium alloy to prevent Be from being released into the atmosphere, the following steps are taken. 12 X and / or Be 13 X-phase decomposition ensures the acquisition of high Be. 12 X and / or Be 13 X phase content. Control the holding temperature of the annealing treatment to 300~600℃, for example 300℃, 400℃, 500℃, 600℃, and hold for 1~2h, for example 1h, 1.5h, 2h.

[0055] Specifically, in step 8, the Be in the beryllium alloy with high quality phase content... 12 X and / or Be 13 The mass percentage of the X phase is above 98%, for example, 98%~99.2%.

[0056] Specifically, in step 8, the beryllium alloy can be in the form of small spheres, rods, sheets, or complex shapes, and the size range of the beryllium alloy is 0.1-200 mm.

[0057] The beryllium alloy prepared by the method of the present invention can be used as a neutron multiplier in fusion reactors.

[0058] The method of this invention, through strict composition control, pretreatment of mixed powder ball milling + annealing, segmented precise temperature-controlled sintering, ultra-fast cooling, and subsequent low-temperature annealing, ensures the production of beryllium alloys with high-quality phase content. It also significantly improves the microstructure uniformity and density of the beryllium alloys, effectively avoiding defects such as internal stress and cracks that may occur during ultra-fast cooling. This results in beryllium alloys with superior mechanical properties and structural stability, enabling them to maintain good performance under the harsh operating environment of fusion reactors and extend their service life.

[0059] The beryllium alloy prepared by the method of this invention has a relative density of over 95%, and the Be in the beryllium alloy... 12 X and / or Be 13 The X phase has a mass percentage of over 98%, making this ultra-high purity Be. 12 X and / or Be 13 The superior X phase endows beryllium alloys with excellent neutron multiplication properties, which can effectively compensate for the loss of neutron yield caused by the reduction of beryllium content, thereby better meeting the urgent need for high-efficiency neutron multiplication materials and providing material support for achieving "tritium self-sufficiency".

[0060] The beryllium alloy prepared by the method of the present invention has excellent mechanical properties, such as a room temperature compressive strength of more than 1800 MPa, for example, 1800~2700 MPa.

[0061] The method of this invention has the advantages of high process controllability and good repeatability. By precisely controlling key parameters such as raw material ratio, ball mill pretreatment, sintering temperature, holding time, cooling rate and annealing process, beryllium alloys with high quality phase content can be stably prepared, which is conducive to realizing industrial production.

[0062] The advantages of the precise control of the method of the present invention are demonstrated below with specific embodiments and comparative examples.

[0063] Example 1 This embodiment provides a method for increasing the content of high-quality phases in beryllium alloys, and the specific steps are as follows: Step 1: Using spherical beryllium powder with a purity ≥99.0% and spherical titanium powder with a purity ≥99.9%, the powders are precisely weighed according to a Be:Ti atomic ratio of 12.2:1. Then, a high-energy ball milling pretreatment is performed. The prepared powders are placed in a high-energy planetary ball mill, using a cemented carbide grinding jar and grinding balls. Under argon protection, the powders are ball-milled at 700 rpm for 6.5 hours at a ball-to-powder ratio of 2:1. Afterward, the powders are placed in a vacuum annealing furnace and held at 950℃ for 8 hours, then cooled to room temperature with the furnace. Step 2: The above-mentioned beryllium titanium pre-alloy powder and binder are mixed in an intensive kneading process. The binder composition (wt%) is: polyoxymethylene 72, acrylonitrile-butadiene-styrene copolymer 5, high-density polyethylene 5, ethylene-vinyl acetate copolymer 4, stearic acid 3, paraffin wax 4, polyethyleneimine 3, triethanolamine 2, BASF antioxidant 2. The mass ratio of binder to mixed powder is 30:70. The mixing is carried out in an argon-filled internal mixer at a temperature of 180℃, a rotation speed of 40 rpm, and a time of 60 min to obtain a uniform feed agglomerate. Step 3: The feed agglomerate is granulated through a twin-screw extruder. The screw temperature is controlled in zones: 170 ℃ for the feeding section, 170 ℃ for the mixing section, and 180 ℃ for the discharge section. The extruded strip material is air-cooled and then granulated to obtain granular feed with uniform particle size (about 1.9~2mm). Step 4: Using an injection molding machine, feed the material into the spherical cavity mold. The barrel temperature from the feeding section to the nozzle is 150℃, 150℃, 163℃, 165℃, and 170℃ respectively. The mold temperature is 78℃. The injection uses two-stage pressure control: first, the injection pressure is 110MPa for rapid filling, then it is switched to 95MPa for stable filling, and finally, it is switched to 50MPa for holding pressure for 5 seconds to form a spherical green body. Step 5: Place the green body in a catalytic degreasing furnace filled with oxalic acid vapor, set the temperature to 128℃, and keep it at that temperature for 8 hours to remove the polyoxymethylene component. Step 6: Transfer the catalytically degreased billet to a vacuum degassing furnace, heat it to 400℃ at a rate of 2℃ / min and hold for 1 hour, continue to heat it to 600℃ and hold for 1 hour, continue to heat it to 800℃ and hold for 1 hour to completely remove the remaining binder and obtain a clean beryllium titanium billet. Step 7: Place the green blank in a high-temperature furnace protected by high-purity argon gas, heat it to 850°C at a rate of 5°C / min, and hold it at this temperature for 1 hour for pre-firing; then heat it to 1100°C and hold it at this temperature for 4 hours to achieve solid-state sintering densification. Step 8: After the heat preservation is completed, immediately start the ultra-fast cooling system and use high-pressure argon gas to cool the beryllium titanium microsphere sintered body from 1100℃ to below 250℃ within 20 minutes. Step 9: Place the rapidly cooled beryllium titanium microspheres in a high-purity argon-protected furnace, heat to 450℃ at 5℃ / min, hold for 1.5h, and then cool to room temperature with the furnace to obtain beryllium titanium alloy microspheres with high quality phase content.

[0064] Figure 1 The image shown is a SEM image of the beryllium titanium microspheres in this embodiment. Figure 2 The image shown is the XRD pattern of the beryllium titanium microspheres in this embodiment.

[0065] Performance characterization: XRD analysis showed that the Be in the beryllium alloy obtained in this embodiment...12 Ti phase accounted for 98.0 wt%, and no free pure Be or pure Ti phase was detected; Figure 1 The image shown is an SEM image of the beryllium alloy in this embodiment. It can be seen that the microstructure of the beryllium alloy is uniform. The density of the beryllium titanium microspheres, measured using Archimedes' displacement method, is 2.24 g / cm³. According to Be... 12 The theoretical density of Ti is 2.28 g / cm³, resulting in a relative density of over 98.24%. The beryllium-titanium microspheres in this embodiment have a room temperature compressive strength of 1800 MPa.

[0066] Example 2 This embodiment provides a method for increasing the content of high-quality phases in beryllium alloys. The overall steps are the same as in Embodiment 1, except for a few different process parameters: Under argon protection, the ball mill was run at 600 rpm and a ball-to-material ratio of 2:1 for 8 hours. Then, it was placed in a vacuum heat annealing furnace and held at 950℃ for 10 hours before being cooled to room temperature with the furnace. Performance characterization: XRD analysis showed that the Be in the beryllium alloy obtained in this embodiment... 12 The Ti phase accounts for more than 98.6 wt%, and no free pure Be or pure Ti phase was detected; the microstructure of the beryllium alloy in this embodiment is uniform. The density of the beryllium titanium microspheres was measured to be 2.25 g / cm³ using the Archimedes displacement method. 12 The theoretical density of Ti is 2.28 g / cm³, resulting in a relative density of over 98.6%. The beryllium-titanium microspheres in this embodiment have a room temperature compressive strength of 1850 MPa.

[0067] Example 3 This embodiment provides a method for increasing the content of high-quality phases in beryllium alloys. The preparation of beryllium-tungsten alloys in this embodiment is largely the same as in Embodiment 1, with the difference being: Step 1: Use spherical beryllium powder with a purity ≥99.0% and spherical tungsten powder with a purity ≥99.9% and weigh them precisely according to the Be:W atomic ratio of 12.2:1. Then, perform high-energy ball milling pretreatment. Place the prepared powder in a high-energy planetary ball mill, use a cemented carbide ball milling jar and grinding balls, and ball mill for 6.5 hours under argon protection at a speed of 800 rpm and a ball-to-powder ratio of 2:1. Then, load it into a vacuum hot annealing furnace, hold it at 950℃ for 8 hours, and then cool it to room temperature with the furnace. Step 2: The above-mentioned beryllium tungsten pre-alloyed powder is mixed with a binder. The binder composition (wt%) is: polyoxymethylene 74, acrylonitrile-butadiene-styrene copolymer 6, high-density polyethylene 6, ethylene-vinyl acetate copolymer 3, stearic acid 2, paraffin wax 3, polyethyleneimine 3, triethanolamine 2, and BASF antioxidant 1. The mass ratio of binder to mixed powder is 32:68. The mixing is carried out in an argon-filled internal mixer at a temperature of 180°C, a rotation speed of 40 rpm, and a time of 60 min to obtain a uniform feed agglomerate. The amount of binder is controlled to prevent stratification caused by large differences in powder density during mixing.

[0068] Steps 3 and 4 are the same as in Example 1, and will not be repeated here; Step 5: Place the green billet in a catalytic degreasing furnace filled with oxalic acid vapor, set the temperature to 128℃, and hold for 8.5 hours; Step 6: Transfer the catalytically degreased billet to a vacuum degassing furnace, heat it to 400℃ at a rate of 2℃ / min and hold for 1 hour, continue to heat it to 600℃ and hold for 1 hour, continue to heat it to 800℃ and hold for 2 hours to completely remove the remaining binder and obtain a clean beryllium tungsten billet. Step 7: Place the green blank in a high-temperature furnace protected by high-purity argon gas, raise the temperature to 850°C at 5°C / min, and hold for 1 hour for pre-firing; then raise the temperature to 1180°C and hold at this temperature for 6 hours to achieve solid-state sintering densification. Step 8: After the heat preservation is completed, immediately start the ultra-fast cooling system and use high-pressure argon gas to cool the beryllium titanium microsphere sintered body from 1180℃ to below 250℃ within 20 minutes. Step 9 is the same as in Example 1, and will not be repeated here.

[0069] Performance Characterization: XRD analysis showed that the Be in the beryllium-tungsten alloy obtained in this embodiment... 12 The W phase accounted for 98.3 wt%, and no free pure Be or pure W phase was detected; the microstructure of the beryllium-tungsten alloy in this embodiment was uniform. The density of the beryllium-tungsten microspheres was measured to be 4.22 g / cm³ using the Archimedes' displacement method. 12 The theoretical density of W is 4.44 g / cm³, yielding a relative density of 95.1%. The room temperature compressive strength of the beryllium-tungsten microspheres in this embodiment is 2700 MPa.

[0070] Example 4 This embodiment provides a method for increasing the content of high-quality phases in beryllium alloys. The preparation of beryllium-vanadium alloys in this embodiment is largely the same as in Embodiment 1, with the difference being: Step 1: Use spherical beryllium powder with a purity ≥99.0% and spherical vanadium powder with a purity ≥99.9%, and accurately calculate and weigh them according to the Be:V atomic ratio of 12.2:1. Then, perform high-energy ball milling pretreatment. Place the prepared powder in a high-energy planetary ball mill, use a cemented carbide ball milling jar and grinding balls, and ball mill for 6.5 hours under argon protection at a speed of 700 rpm and a ball-to-powder ratio of 2:1. Then, load it into a vacuum hot annealing furnace, hold it at 950℃ for 8 hours, and then cool it to room temperature with the furnace. Steps 2-6 are the same as in Example 1, and will not be repeated here; Step 7: Place the green blank in a high-temperature furnace protected by high-purity argon gas, raise the temperature to 850°C at 5°C / min, and hold for 1 hour for pre-firing; then raise the temperature to 1150°C and hold at this temperature for 5 hours to achieve solid-state sintering densification. Step 8: After the heat preservation is completed, immediately start the ultra-fast cooling system and use high-pressure argon gas to cool the beryllium titanium microsphere sintered body from 1150℃ to below 250℃ within 20 minutes. Step 9 is the same as in Example 1, and will not be repeated here.

[0071] Performance Characterization: XRD analysis showed that the Be in the beryllium-vanadium alloy obtained in this embodiment... 12 The V phase accounted for 99.1 wt%, and no free pure Be or pure V phase was detected; the microstructure of the beryllium vanadium alloy in this embodiment was uniform. The density of the beryllium vanadium microspheres was measured to be 2.42 g / cm³ using the Archimedes displacement method. 12 The theoretical density of V is 2.45 g / cm³, yielding a relative density of over 98.7%. The room temperature compressive strength of the beryllium vanadium microspheres in this embodiment is 2000 MPa.

[0072] Example 5 This embodiment provides a method for increasing the content of high-quality phases in beryllium alloys. The preparation of beryllium-zirconium alloys in this embodiment is largely the same as in Embodiment 1, with the difference being: Step 1: Use spherical beryllium powder with a purity ≥99.0% and spherical zirconium powder with a purity ≥99.9%, and accurately calculate and weigh them according to the Be:Zr atomic ratio of 13.2:1; then, perform high-energy ball milling pretreatment. Place the prepared powder in a high-energy planetary ball mill, use a cemented carbide ball milling jar and grinding balls, and ball mill for 6.5 hours under argon protection at a speed of 800 rpm and a ball-to-powder ratio of 2:1. Then, load it into a vacuum hot annealing furnace, hold it at 950℃ for 8 hours, and then cool it to room temperature with the furnace. Step 2: The above-mentioned beryllium-zirconium pre-alloyed powder is mixed with a binder. The binder composition (wt%) is: polyoxymethylene 73, acrylonitrile-butadiene-styrene copolymer 5.5, high-density polyethylene 5.5, ethylene-vinyl acetate copolymer 4, stearic acid 2, paraffin wax 4, polyethyleneimine 3, triethanolamine 1, BASF antioxidant 2; the mass ratio of binder to mixed powder is 32:68. The mixing is carried out in an argon-filled internal mixer at a temperature of 180℃, a rotation speed of 40 rpm, and a time of 60 min to obtain a uniform feed agglomerate. The amount of binder is controlled to prevent stratification caused by large differences in powder density during mixing. Steps 3 and 4 are the same as in Example 1, and will not be repeated here. Step 5: Place the green billet in a catalytic degreasing furnace filled with oxalic acid vapor, set the temperature to 128℃, and hold for 8.5 hours; Step 6: Transfer the catalytically degreased billet to a vacuum degassing furnace, heat it to 400℃ at a rate of 2℃ / min and hold for 1 hour, continue to heat it to 600℃ and hold for 1 hour, continue to heat it to 800℃ and hold for 2 hours to obtain a clean beryllium tungsten billet. Step 7: Place the green blank in a high-temperature furnace protected by high-purity argon gas, raise the temperature to 850°C at 5°C / min, and hold for 1 hour for pre-firing; then raise the temperature to 1100°C and hold at this temperature for 4.5 hours to achieve solid-state sintering densification. Step 8: After the heat preservation is completed, immediately start the ultra-fast cooling system and use high-pressure argon gas to cool the beryllium zirconium microsphere sintered body from 1100℃ to below 250℃ within 20 minutes. Step 9 is the same as in Example 1, and will not be repeated here.

[0073] Performance Characterization: XRD analysis showed that the Be in the beryllium-zirconium alloy obtained in this embodiment... 13 The Zr phase accounted for 98.9 wt%, and no free pure Be or pure Zr phase was detected; the microstructure of the beryllium-zirconium alloy in this embodiment was uniform. The density of the beryllium-zirconium microspheres was measured to be 2.73 g / cm³ using the Archimedes displacement method. 13 The theoretical density of Zr is 2.77 g / cm³, resulting in a relative density of over 98.5%. The room temperature compressive strength of this embodiment is 2300 MPa.

[0074] The inventors conducted extensive research during the research process, and some poorly performing solutions are now presented as comparative examples.

[0075] Comparative Example 1 This comparative example provides a method for preparing a beryllium alloy, the specific steps of which are as follows: Step 1: Use spherical beryllium powder with a purity ≥99.5% and spherical titanium powder with a purity ≥99.9%, and accurately calculate and weigh them according to the Be:Ti atomic ratio of 12:1. Then, perform high-energy ball milling pretreatment. Place the prepared powder in a high-energy planetary ball mill, use a cemented carbide grinding jar and grinding balls, and ball mill for 6.5 hours under argon protection at a speed of 700 rpm and a ball-to-powder ratio of 2:1.

[0076] Steps 2 through 7 are exactly the same as in Example 1.

[0077] Step 8: After the heat preservation is completed, cool the furnace.

[0078] Performance characterization: XRD results show that Be in the final sample 12 The Ti phase content was 79.3 wt%, while the Be phase content was... 17 The Ti2 phase content reached 19.3 wt%, and no free beryllium or titanium elemental phases were found. The room temperature compressive strength of the beryllium alloy is 800 MPa.

[0079] Comparative Example 2 This comparative example provides a method for preparing a beryllium alloy, the specific steps of which are as follows: Steps 1 to 7 are exactly the same as in Example 1.

[0080] Step 8: After the heat preservation is completed, cool the furnace.

[0081] Step 9: Place the sintered beryllium titanium microspheres in a high-purity argon-protected furnace, heat to 450°C at 5°C / min, hold for 1.5 hours, and then cool to room temperature with the furnace.

[0082] Effect characterization: Semi-quantitative analysis was performed after XRD testing, and the results showed that Be 12 The Ti phase content was 81.3 wt%, and the Be content was... 17 The Ti2 phase content was 17.5 wt%, and free pure Ti phase was detected.

[0083] Comparative Example 3 This comparative example provides a method for preparing a beryllium alloy, the specific steps of which are as follows: Steps 1 to 8 are exactly the same as in Example 1. Step 9 of Example 1 is omitted.

[0084] Effect characterization: Semi-quantitative analysis was performed after XRD testing, and the results showed that Be 12 The Ti phase content was 97.4 wt%, with only trace amounts of Be detected. 17 Ti2 phase was not detected; no free pure Be or pure Ti phase was found. The density of the beryllium titanium microspheres was determined to be 2.11 g / cm³ using the Archimedes displacement method. 12The theoretical density of Ti is 2.28 g / cm³, resulting in a relative density of only 92.54%; its room temperature compressive strength is 900 MPa.

[0085] Comparative Example 4 This comparative example provides a method for preparing a beryllium alloy, the specific steps of which are as follows: Steps 1 to 6, 8 and 9 are exactly the same as in Example 1.

[0086] Step 7: Place the green blank in a high-temperature furnace protected by high-purity argon gas, and directly heat it to 1000℃ at a rate of 5℃ / min, and hold it at this temperature for 4 hours.

[0087] Characterization of effects: Due to unsuitable sintering process, atomic diffusion was insufficient, and the reaction was incomplete. XRD analysis showed that Be... 12 The Ti phase content was 77.2 wt%, with the remainder being free pure Be and pure Ti phase. The density of the beryllium titanium microspheres was determined to be 2.14 g / cm³ using the Archimedes displacement method. 12 The theoretical density of Ti is 2.2 g / cm³, yielding a relative density of 93.86%. Its room temperature compressive strength is 1400 MPa.

[0088] Comparative Example 5 This comparative example provides a method for preparing a beryllium alloy, the specific steps of which are as follows: Step 1 is exactly the same as in Example 1; In step 2, the binder composition (wt%) is: polyoxymethylene 82, acrylonitrile-butadiene-styrene copolymer 2, high-density polyethylene 2, ethylene-vinyl acetate copolymer 2, stearic acid 3, paraffin wax 4, polyethyleneimine 3, triethanolamine 2; the mass ratio of binder to mixed powder is 30:70, and the mixing is carried out in an argon-filled internal mixer at a temperature of 180℃, a rotation speed of 40 rpm, and a time of 60 min to obtain a uniform feed agglomerate; Steps 3 through 9 are exactly the same as in Example 1.

[0089] Performance characteristics: Due to inappropriate control of binder composition, the density of the green blank after degreasing was too low, the green blank lacked mechanical strength and could not support sintering. In addition, the carbon residue was high during the degreasing process, exceeding 2wt%, which affected the stability of the neutron multiplier in the fusion reaction.

[0090] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for increasing the content of high-quality phases in beryllium alloys, characterized in that, Includes the following steps: Step 1: Weigh beryllium powder and X powder according to the atomic ratio of Be to X of 12.1~13.3:1, wherein X is at least one of Ti, W, V or Zr; Step 2: Pre-treat the mixture of beryllium powder and X powder by ball milling; Step 3: Anneal the pretreated mixed powder; Step 4: The annealed mixed powder and binder are kneaded and granulated to obtain the feedstock; the mass percentages of each component of the binder are as follows: polyoxymethylene 62~82%, acrylonitrile butadiene The composition includes 4-6% styrene copolymer, 4-6% high-density polyethylene, 3-5% ethylene-vinyl acetate copolymer, 2-4% stearic acid, 3-5% paraffin wax, 2-4% polyethyleneimine, 1-3% triethanolamine, and 1-3% BASF antioxidant; wherein the density of the high-density polyethylene ranges from 0.941 to 0.965 g / cm³. 3 ; Step 5: Prepare green blanks using injection molding process; Step 6: Remove the binder from the green body through a degreasing process to obtain the raw green body; Step 7: Sinter the green body under a protective atmosphere. The sintering process includes the following steps: S701. Place the green billet in a high-temperature furnace under a protective atmosphere and heat it to 845~855℃ and hold it thereafter. S702, heat to 1000~1185℃ and hold; S703. After the heat preservation is completed, ultra-fast cooling is used to rapidly cool the sintered body to below 250°C; the cooling rate of ultra-fast cooling is above 42°C / min. Step 8: Perform low-temperature annealing on the cooled material to obtain a beryllium alloy with high quality phase content.

2. The method according to claim 1, characterized in that, In step 2, the ball-to-material ratio is 2~3:

1.

3. The method according to claim 2, characterized in that, In step 2, the ball milling speed is 600~800 rpm and the ball milling time is 5~8 hours.

4. The method according to claim 1, characterized in that, In step 3, the annealing process includes the following steps: the mixed powder is loaded into a vacuum heat treatment furnace, kept at 800~1000℃ for 1~10h and then cooled to room temperature.

5. The method according to claim 1, characterized in that, In step 4, the mass ratio of binder to mixed powder is controlled to be 27~32:68~73.

6. The method according to claim 1, characterized in that, In step 4, the mixing process is controlled at a temperature of 175~185℃ and a speed of 35~45rpm for 55~65min.

7. The method according to claim 1, characterized in that, In step 6, the degreasing process includes two steps: catalytic degreasing and thermal degreasing. Catalytic degreasing includes the following steps: placing the green body in a degreasing furnace filled with oxalic acid vapor and keeping it at a temperature of 125~130 ℃ for 8~10 hours.

8. The method according to claim 1, characterized in that, In the S703, the ultra-fast cooling rate is 42~60℃ / min.

9. The method according to any one of claims 1 to 8, characterized in that, In step 8, the holding temperature for annealing is 300~600℃.

10. A beryllium alloy with high content of a high-quality phase, characterized in that, The beryllium alloy with high quality phase content is prepared by the method described in any one of claims 1 to 9.

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