A method for preparing a nanoparticle-reinforced beryllium-based composite

Abstract

This invention provides a method for preparing nanoparticle-reinforced beryllium-based composite materials, comprising the following steps: S1. Ball milling and mixing: beryllium powder and nano-ceramic particles are mixed to obtain a mixed powder. The mixed powder is placed in a ball mill and ball milled at high energy under inert gas protection or at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder; S2. Ultrasonic dispersion: the preliminary mixed powder, process control agent, and liquid medium are mixed and magnetically stirred to obtain slurry one, and ultrasonically vibrated to obtain slurry two; S3. Drying and molding: slurry two is filtered to obtain filtrate, which is then vacuum dried in a vacuum drying oven to obtain composite powder. The composite powder is then pressed into a compact to obtain a pressed compact; S4. Hot isostatic pressing sintering: the pressed compact is placed in a vacuum sintering furnace for hot isostatic pressing sintering, cooled to room temperature with the furnace, and then removed to obtain the nanoparticle-reinforced beryllium-based composite material. This invention effectively solves the problem of uneven dispersion of nano-ceramic particles in beryllium powder, and prepares a composite material with uniform structure and excellent performance.

Description

Technical Field

[0001] This invention relates to a method for preparing nanoparticle-reinforced beryllium-based composite materials. Background Technology

[0002] Beryllium and its alloys possess irreplaceable application value in aerospace, defense, and nuclear industries due to their advantages such as low density, high specific strength, high specific stiffness, excellent thermal conductivity, and good nuclear properties. However, the poor room-temperature plasticity and insufficient strength, especially at high temperatures, of pure beryllium limit its further application in extreme environments.

[0003] To improve the properties of beryllium, researchers have attempted to prepare beryllium-based composites by introducing reinforcing phases. Among these, ceramic particle reinforcing phases, such as silicon carbide (SiC), alumina (Al₂O₃), titanium diboride (TiB₂), and titanium carbide (TiC), show promise as effective reinforcements for beryllium alloys. Although the reinforcing effect significantly improves when the size of the reinforcing phase is reduced to the nanoscale, nanoparticles have a large specific surface area and high surface energy, making them prone to agglomeration during preparation. This agglomeration not only fails to leverage the reinforcing advantages of nanoparticles but also becomes a crack initiation point, leading to a decline in the overall performance of the material.

[0004] Currently, the main methods for preparing particle-reinforced metal matrix composites include powder metallurgy, melt casting, and stirred casting. For highly reactive beryllium, melt casting easily leads to oxidation and coarse grains, and the nanoparticles are more difficult to disperse in the melt. Although traditional powder metallurgy avoids the melting process, the effect of simple mechanical ball milling on the deagglomeration of nanoclusters is limited, and prolonged ball milling introduces excessive impurities and work hardening, which is detrimental to subsequent sintering.

[0005] Therefore, developing a preparation method that can effectively achieve highly uniform dispersion of nanoparticles in a beryllium matrix and has a stable and reliable process has become the key to promoting the application of high-performance beryllium-based composite materials. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing nanoparticle-reinforced beryllium-based composite materials. This method can effectively solve the problem of uneven dispersion of nano-ceramic particles in beryllium powder and prepare composite materials with uniform structure and excellent performance.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] A method for preparing nanoparticle-reinforced beryllium-based composite materials includes the following steps:

[0009] S1. Ball milling mixing:

[0010] Beryllium powder is mixed with nano-ceramic particles to obtain a mixed powder. The mixed powder is placed in a ball mill and ball milled at high energy under inert gas protection or at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder.

[0011] S2. Ultrasonic diffusion:

[0012] The preliminary mixed powder obtained in step S1, the process control agent, and the liquid medium are mixed and magnetically stirred to obtain slurry one. Slurry one is then ultrasonically vibrated to obtain slurry two.

[0013] S3. Drying and shaping:

[0014] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and vacuum dried to obtain composite powder. The composite powder is loaded into a mold and pressed to form a compact.

[0015] S4. Hot isostatic pressing sintering:

[0016] The compact obtained in step S3 is placed in a vacuum sintering furnace for hot isostatic pressing sintering, and then cooled to room temperature with the furnace. After removal, a nanoparticle-reinforced beryllium-based composite material is obtained.

[0017] Further, in step S1 of the present invention, the beryllium powder has a particle size of 100-200 μm, and the beryllium powder is pure beryllium powder or beryllium-aluminum alloy powder, wherein the mass ratio of beryllium to aluminum in the beryllium-aluminum alloy powder is 62:38; the nano-ceramic particles have a particle size of 20-120 nm, and the nano-ceramic particles are one of Al2O3 nanoparticles, TiC nanoparticles, or TiB2 nanoparticles; the mass ratio of beryllium powder to nano-ceramic particles is (95-100):3.

[0018] Furthermore, in step S1 of the present invention, the grinding balls used in the ball mill are stainless steel grinding balls, and the ball-to-material ratio of the mixed powder to the stainless steel grinding balls is (5-10):1; the rotation speed for high-energy ball milling is 200 rpm, the temperature is room temperature, the time is 4-8 h, and the inert gas is argon; the rotation speed for low-temperature ball milling is 200 rpm, the temperature is 0 °C, and the time is 6-12 h.

[0019] Furthermore, in step S2 of the present invention, the ratio of the preliminary mixed powder, process control agent, and liquid medium obtained in step S1 is 100g:1g:(150-250)mL, the process control agent is stearic acid, and the liquid medium is anhydrous ethanol or acetone.

[0020] Furthermore, in step S2 of the present invention, the magnetic stirring speed is 200 rpm and the time is 8-12 min; the ultrasonic vibration power is 1000 W, the frequency is 25 kHz, and the time is 15-25 min.

[0021] Furthermore, in step S3 of the present invention, the vacuum drying temperature is 60-80℃ and the time is 8-12h.

[0022] Furthermore, in step S3 of the present invention, the pressing pressure is 10-50 MPa and the time is 20-40 min.

[0023] Furthermore, in step S4 of the present invention, the vacuum degree of hot isostatic pressing sintering is 0.1-10 Pa, the temperature is 500-900℃, the pressure is 50-100 MPa, and the time is 5-20 min.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) This invention innovatively adopts a two-step method combining "high-energy / low-temperature ball milling" and "ultrasonic vibration": ball milling achieves the initial mixing of the reinforcing phase and the matrix, while the subsequent ultrasonic treatment utilizes the cavitation effect in the liquid phase environment to achieve the deagglomeration of nanoclusters and uniform dispersion at the microscale, thereby solving the problem of nanoparticle agglomeration. In the subsequent sintering process, an interface with higher bonding strength is formed, which is conducive to the effective transfer of load from the matrix to the reinforcement, and further improves the performance of the composite material.

[0026] 2) The entire process of this invention is carried out at a low temperature, which avoids severe oxidation of beryllium and excessive grain growth. The process parameters are easy to control, have good repeatability, and are suitable for large-scale production. Detailed Implementation

[0027] The present invention will now be described in detail with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0028] Example 1

[0029] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0030] S1. Ball milling mixing:

[0031] Pure beryllium powder with a particle size of 200 μm and Al2O3 nanoparticles with a particle size of 100 nm were mixed at a mass ratio of 97:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled under argon protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-powder ratio of the mixed powder to the stainless steel grinding balls was 8:1. The high-energy ball milling speed was 200 rpm, the temperature was room temperature, and the time was 5 h.

[0032] S2. Ultrasonic diffusion:

[0033] The preliminary mixed powder obtained in step S1, stearic acid, and anhydrous ethanol are mixed in a ratio of 100g:1g:200mL and magnetically stirred at 200rpm for 10min to obtain slurry one. Slurry one is then ultrasonically vibrated at 1000W power and 25kHz frequency for 20min to obtain slurry two.

[0034] S3. Drying and shaping:

[0035] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under 10MPa pressure for 30 minutes to obtain a pressed blank.

[0036] S4. Hot isostatic pressing sintering:

[0037] The compact obtained in step S3 is placed in a vacuum sintering furnace, evacuated to a vacuum degree of 0.5 Pa, heated to 900 °C, and hot isostatically sintered at 100 MPa for 15 min. Then it is cooled to room temperature with the furnace and removed to obtain nanoparticle-reinforced beryllium-based composite material.

[0038] The nanoparticle-reinforced beryllium-based composite material was tested according to GB / T 228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method. The results showed that the tensile strength could reach 450 MPa.

[0039] Comparative example:

[0040] The difference from Example 1 is that the ball milling time in step S1 is extended to 8 hours, and step S2 is omitted. The tensile strength of the composite material prepared in the comparative example is 410 MPa. The test results show that the tensile strength of the nanoparticle-reinforced beryllium-based composite material prepared by the method of the present invention is higher than that of the composite material prepared by ball milling alone.

[0041] Example 2

[0042] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0043] S1. Ball milling mixing:

[0044] Pure beryllium powder with a particle size of 100 μm and TiC nanoparticles with a particle size of 100 nm were mixed at a mass ratio of 95:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled under argon protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-particle ratio of the mixed powder to the stainless steel grinding balls was 5:1. The high-energy ball milling speed was 200 rpm, the temperature was room temperature, and the time was 4 h.

[0045] S2. Ultrasonic diffusion:

[0046] The preliminary mixed powder obtained in step S1, stearic acid, and acetone are mixed in a ratio of 100g:1g:150mL and magnetically stirred at 200rpm for 8min to obtain slurry one. Slurry one is then ultrasonically vibrated at 1000W power and 25kHz frequency for 15min to obtain slurry two.

[0047] S3. Drying and shaping:

[0048] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and dried at 80°C for 8 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under a pressure of 50MPa for 20 minutes to obtain a pressed blank.

[0049] S4. Hot isostatic pressing sintering:

[0050] The compact obtained in step S3 is placed in a vacuum sintering furnace, evacuated to a vacuum degree of 0.1 Pa, heated to 800 °C, and hot isostatically sintered at 50 MPa for 5 min. Then it is cooled to room temperature with the furnace and removed to obtain nanoparticle-reinforced beryllium-based composite material.

[0051] Example 3

[0052] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0053] S1. Ball milling mixing:

[0054] Beryllium-aluminum alloy powder with a particle size of 150 μm (the mass ratio of beryllium to aluminum in the beryllium-aluminum alloy powder is 62:38) was mixed with TiB2 nanoparticles with a particle size of 120 nm at a mass ratio of 97:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled under argon protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-particle ratio of the mixed powder to the stainless steel grinding balls was 10:1. The high-energy ball milling speed was 200 rpm, the temperature was room temperature, and the time was 8 h.

[0055] S2. Ultrasonic diffusion:

[0056] The preliminary mixed powder obtained in step S1, stearic acid, and anhydrous ethanol are mixed in a ratio of 100g:1g:250mL and magnetically stirred at 200rpm for 12min to obtain slurry one. Slurry one is ultrasonically vibrated at 1000W power and 25kHz frequency for 25min to obtain slurry two.

[0057] S3. Drying and shaping:

[0058] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and dried at 70°C for 10 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under a pressure of 20MPa for 40 minutes to obtain a pressed blank.

[0059] S4. Hot isostatic pressing sintering:

[0060] The compact obtained in step S3 is placed in a vacuum sintering furnace, evacuated to a vacuum degree of 10 Pa, heated to 500 °C, and hot isostatically sintered at 80 MPa for 20 min. Then it is cooled to room temperature with the furnace and removed to obtain nanoparticle-reinforced beryllium-based composite material.

[0061] Example 4

[0062] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0063] S1. Ball milling mixing:

[0064] Pure beryllium powder with a particle size of 200 μm and TiC nanoparticles with a particle size of 100 nm were mixed at a mass ratio of 98:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-particle ratio of the mixed powder to the stainless steel grinding balls was 7:1. The ball milling speed was 200 rpm, the temperature was 0℃, and the time was 9 h.

[0065] S2. Ultrasonic diffusion:

[0066] The preliminary mixed powder obtained in step S1, stearic acid, and anhydrous ethanol are mixed in a ratio of 100g:1g:180mL and magnetically stirred at 200rpm for 10min to obtain slurry one. Slurry one is then ultrasonically vibrated at 1000W power and 25kHz frequency for 20min to obtain slurry two.

[0067] S3. Drying and shaping:

[0068] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under a pressure of 30MPa for 30 minutes to obtain a pressed blank.

[0069] S4. Hot isostatic pressing sintering:

[0070] The compact obtained in step S3 is placed in a vacuum sintering furnace, evacuated to a vacuum degree of 1 Pa, heated to 600°C, and hot isostatically sintered at 90 MPa for 10 min. Then it is cooled to room temperature with the furnace and removed to obtain a nanoparticle-reinforced beryllium-based composite material.

[0071] Example 5

[0072] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0073] S1. Ball milling mixing:

[0074] Pure beryllium powder with a particle size of 100 μm and TiB nanoparticles with a particle size of 60 nm were mixed at a mass ratio of 96:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-particle ratio of the mixed powder to the stainless steel grinding balls was 6:1. The ball milling speed was 200 rpm, the temperature was 0℃, and the time was 6 h.

[0075] S2. Ultrasonic diffusion:

[0076] The preliminary mixed powder obtained in step S1, stearic acid, and acetone are mixed in a ratio of 100g:1g:210mL and magnetically stirred at 200rpm for 8min to obtain slurry one. Slurry one is then ultrasonically vibrated at 1000W power and 25kHz frequency for 15min to obtain slurry two.

[0077] S3. Drying and shaping:

[0078] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and dried at 80°C for 9 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under a pressure of 40MPa for 20 minutes to obtain a pressed blank.

[0079] S4. Hot isostatic pressing sintering:

[0080] The compact obtained in step S3 is placed in a vacuum sintering furnace, vacuumed to a vacuum degree of 5 Pa, heated to 700 °C, and hot isostatically sintered at a pressure of 60 MPa for 18 min. Then it is cooled to room temperature with the furnace and removed to obtain a nanoparticle-reinforced beryllium-based composite material.

[0081] Example 6

[0082] Nanoparticle-reinforced beryllium-based composite materials were prepared according to the following steps:

[0083] S1. Ball milling mixing:

[0084] Beryllium-aluminum alloy powder with a particle size of 120 μm (the mass ratio of beryllium to aluminum in the beryllium-aluminum alloy powder is 62:38) was mixed with Al2O3 nanoparticles with a particle size of 120 nm at a mass ratio of 99:3 to obtain a mixed powder. The mixed powder was placed in a ball mill and ball milled at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder. The grinding balls used in the ball mill were stainless steel grinding balls, and the ball-to-particle ratio of the mixed powder to the stainless steel grinding balls was 9:1. The ball milling speed was 200 rpm, the temperature was 0℃, and the time was 12 h.

[0085] S2. Ultrasonic diffusion:

[0086] The preliminary mixed powder obtained in step S1, stearic acid, and acetone are mixed in a ratio of 100g:1g:240mL and magnetically stirred at 200rpm for 12min to obtain slurry one. Slurry one is then ultrasonically vibrated at 1000W power and 25kHz frequency for 25min to obtain slurry two.

[0087] S3. Drying and shaping:

[0088] The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and vacuum dried at 70°C for 11 hours to obtain composite powder. The composite powder is loaded into a mold and pressed under a pressure of 40MPa for 40 minutes to obtain a pressed blank.

[0089] S4. Hot isostatic pressing sintering:

[0090] The compact obtained in step S3 is placed in a vacuum sintering furnace, evacuated to a vacuum degree of 2 Pa, heated to 800℃, and hot isostatically sintered at 90 MPa for 8 min. Then it is cooled to room temperature with the furnace and removed to obtain nanoparticle-reinforced beryllium-based composite material.

[0091] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a nanoparticle-reinforced beryllium-based composite material, characterized in that: Includes the following steps: S1. Ball milling mixing: Beryllium powder is mixed with nano-ceramic particles to obtain a mixed powder. The mixed powder is placed in a ball mill and ball milled at high energy under inert gas protection or at low temperature under liquid nitrogen protection to obtain a preliminary mixed powder. S2. Ultrasonic diffusion: The preliminary mixed powder obtained in step S1, the process control agent, and the liquid medium are mixed and magnetically stirred to obtain slurry one. Slurry one is then ultrasonically vibrated to obtain slurry two. S3. Drying and shaping: The slurry obtained in step S2 is filtered twice to obtain filtrate. The filtrate is placed in a vacuum drying oven and vacuum dried to obtain composite powder. The composite powder is loaded into a mold and pressed to form a compact. S4. Hot isostatic pressing sintering: The compact obtained in step S3 is placed in a vacuum sintering furnace for hot isostatic pressing sintering, and then cooled to room temperature with the furnace. After removal, a nanoparticle-reinforced beryllium-based composite material is obtained.

2. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S1, the beryllium powder has a particle size of 100-200 μm and is either pure beryllium powder or beryllium-aluminum alloy powder, with a beryllium to aluminum mass ratio of 62:38; the nano-ceramic particles have a particle size of 20-120 nm and are one of Al2O3 nanoparticles, TiC nanoparticles, or TiB2 nanoparticles; the mass ratio of beryllium powder to nano-ceramic particles is (95-100):

3.

3. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S1, the grinding balls used in the ball mill are stainless steel grinding balls, and the ball-to-material ratio of the mixed powder to the stainless steel grinding balls is (5-10):1; the rotation speed for high-energy ball milling is 200 rpm, the temperature is room temperature, the time is 4-8 h, and the inert gas is argon; the rotation speed for low-temperature ball milling is 200 rpm, the temperature is 0℃, and the time is 6-12 h.

4. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S2, the ratio of the preliminary mixed powder, process control agent, and liquid medium obtained in step S1 is 100g:1g:(150-250)mL, the process control agent is stearic acid, and the liquid medium is anhydrous ethanol or acetone.

5. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S2, the magnetic stirring speed is 200 rpm and the time is 8-12 min; the ultrasonic vibration power is 1000 W, the frequency is 25 kHz, and the time is 15-25 min.

6. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S3, the vacuum drying temperature is 60-80℃ and the time is 8-12h.

7. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S3, the pressing pressure is 10-50 MPa and the time is 20-40 min.

8. The method for preparing a nanoparticle-reinforced beryllium-based composite material according to claim 1, characterized in that: In step S4, the vacuum degree of hot isostatic pressing sintering is 0.1-10 Pa, the temperature is 500-900℃, the pressure is 50-100 MPa, and the time is 5-20 min.