Manufacturing process for tough molybdenum alloys with a Ti3AlC2 ceramic phase

Abstract

The present invention is 3 AlC 2 This is a process for producing tough molybdenum alloys with a ceramic phase, MoO 2 Powder and Ti 3 AlC 2 The powders are mixed and sieved, then subjected to high-temperature hydrogen reduction, and then mixed with coarse crystal Mo powder to obtain a precursor powder, which is then loaded into a treated capsule and hot-pressed sintered. The resulting sintered molybdenum alloy is then subjected to high-temperature treatment, followed by thermoplastic processing, and finally annealing to obtain a high-strength and toughness molybdenum alloy. The present invention relates to the Ti alloy produced by reduction. 3 AlC 2 The ultrafine powder containing Ti is mixed with commercially available coarse crystal molybdenum powder in a certain ratio to form the precursor powder, which is then hot-pressed and sintered to make the molybdenum alloy more dense and finer. The dimensions of the product can be flexibly designed to meet the needs of different working conditions. 3 AlC 2 As the doping phase of ceramic materials, titanium-containing carbon compounds and oxides generated in situ at high temperatures can increase the recrystallization temperature of molybdenum alloys, greatly improving the plasticity and toughness of molybdenum alloys without reducing their strength, and breaking through the performance bottleneck of traditional molybdenum alloys.

Description

[Technical Field]

[0001] This invention belongs to the field of powder metallurgy, and more particularly to a process for producing a tough molybdenum alloy of the Ti3AlC2 ceramic phase. [Background technology]

[0002] Because molybdenum possesses a high melting point, high density, high modulus of elasticity, low coefficient of linear thermal expansion, high wear resistance, and good electrical and thermal conductivity, molybdenum and its alloys have broad potential applications as high-temperature resistant structural and functional materials in various industrial fields such as metallurgy, machinery, chemical industry, nuclear power, electronics, and aerospace.

[0003] Molybdenum alloys possess invaluable advantages in high-temperature applications. Representative products include high-temperature components for devices such as turbine engines in the aerospace industry, missiles in the military industry, and fusion reactors in the nuclear industry, as well as high-temperature nozzles for aircraft engines and molybdenum plugs in the metallurgical industry. Molybdenum plugs are used in the manufacture of seamless pipes made of stainless steel, alloy steel, and high-temperature alloys, where high high-temperature strength and hardness are required. Turbine engines and high-temperature nozzles require materials that do not recrystallize at high temperatures and possess excellent high-temperature strength and plasticity. High-temperature components for devices such as fusion reactors have extremely high demands for safety and reliability, requiring materials that not only have good radiation resistance but also excellent high-temperature structural stability, high-temperature strength, and plasticity. The high strength and high plasticity of molybdenum alloys represent a developmental trend in high-quality high-temperature molybdenum alloys.

[0004] Conventional tough molybdenum alloys made of carbides, oxides, and rare earths have reached a bottleneck. The novel Ti3AlC2 ceramic crystal, with its layered hexagonal structure and unique crystal structure, offers the potential to further improve the performance of molybdenum alloys by combining many advantages of ceramic and metallic materials, such as high melting point, high damage tolerance, good thermal stability, creep resistance, and oxidation resistance. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a manufacturing process for a tough molybdenum alloy with a Ti3AlC2 ceramic phase, in which a reduced Ti3AlC2 ceramic phase-containing powder is mixed with commercially available crude crystalline molybdenum powder to form a precursor powder, and after hot-press sintering, the density of the molybdenum alloy is increased, the crystal grains are made finer, the shape and dimensions of the product can be flexibly designed, and the usage needs of different working conditions can be met. The titanium-containing carbon compound and oxide generated in situ at high temperature using the Ti3AlC2 ceramic material as a doping phase can raise the recrystallization temperature of the molybdenum alloy by 600°C, significantly improving the plasticity and toughness of the molybdenum alloy without reducing its strength, and overcoming the performance bottleneck of conventional molybdenum alloys. The manufactured Ti3AlC2 ceramic phase is a tough molybdenum alloy material with a density of over 99.5%, a recrystallization temperature of 1600°C, a tensile strength of over 1000 MPa, an elongation of over 50%, and maintains a compressive strength of over 240 MPa at 1400°C, showing promising potential for a wide range of applications in high-temperature fields. [Means for solving the problem]

[0006] The present invention is specifically realized by the following technical solutions, and according to the present invention, (1): Depending on the needs of the final product, weigh a certain amount of MoO2 powder and Ti3AlC2 powder, dry-mix them in a dual-power mixer for 12 to 32 hours, and sift them to prepare them for use. (2): The powder produced in step (1) is subjected to a hydrogen atmosphere of reducing gas at a reduction temperature of 750-1000°C and a hydrogen flow rate of 12-20 m³. 3 The process involves high-temperature reduction at a rate of 6-24 hours, with a powder laying height of ≤4 / 5, and then mixing the reduced Ti3AlC2 ceramic phase-containing powder with commercially available coarse-grained Mo powder in a constant ratio in a dual-power mixer for 10-20 hours to obtain a precursor powder. (3): Selecting an appropriate capsule material according to the dimensions required for the final product, and performing ultrasonic cleaning and preheating of the capsule material before loading the powder, (4): A certain amount of the precursor powder obtained in step (2) is weighed, loaded into the capsule material processed in step (3), loaded while vibrating, the top and bottom of the capsule material are sealed, the edges are welded and the airtightness is checked. (5) The capsules filled with powder are placed in a muffle furnace and heated to 500-600°C to remove any crystalline water present, and then degassed at high temperature for 8-20 hours using a vacuum exhaust system until the vacuum inside the capsule reaches 1 × 10⁻⁶ -3 ~1 × 10 -5 After reaching pa, the exhaust port is sealed by argon arc welding, and then hot press sintering is performed to obtain a sintered molybdenum alloy. (6): The sintered molybdenum alloy obtained in step (5) was poured at a flow rate of 5-15 m 3 The steps include heating to 1200-1600°C under a protective atmosphere of / h, holding the temperature for 30-60 minutes, and then performing thermoplastic processing to obtain a molybdenum alloy billet, (7): The molybdenum alloy billet obtained in step (6) is annealed in a protective atmosphere to finally obtain a highly dense and highly tough molybdenum alloy. The present invention provides a process for producing a tough molybdenum alloy of the Ti3AlC2 ceramic phase, which includes these steps.

[0007] Preferably, the Ti3AlC2 used in step (1) has a layered structure, a purity of 99% or more, a particle size of 2 to 10 μm, the molybdenum dioxide used has a particle size of 8 to 20 μm, the potassium impurity content is 5 to 10 ppm, and the commercially available coarse crystalline Mo powder used in step (2) has a particle size of 3 to 8 μm.

[0008] Preferably, the ultrasonic cleaning temperature in step (3) is 30-60°C and the time is 30-60 min, and the preheating treatment involves placing the capsule material in a muffle furnace and keeping it at 500-600°C for 1-2 hours, and then cooling it in the furnace after the heating is complete.

[0009] Preferably, during powder loading in step (4), the vibration amplitude is 3 - 5 mm, the vibration frequency is 280 - 350 times / min, and the vibration time is 15 - 30 min.

[0010] Preferably, in step (5), the temperature of hot press sintering is 1300 - 1900 °C, the sintering time is 4 - 10 h, and the microscopic structure of the sintered molybdenum alloy includes molybdenum crystal grains and nano - TiC uniformly distributed in the molybdenum alloy. 0.67 The particle size of the molybdenum crystal grains is 5 - 20 μm, and the average particle size of TiC 0.67 is 50 - 200 nm.

[0011] Preferably, the thermoplastic processing in step (6) is one or a combination of more than one of rotary forging, rolling, extrusion or drawing. The block rolling temperature of the thermoplastic processing is 1300 - 1600 °C, the total number of passes is 2 - 6, the deformation amount of each pass is 20 - 30%, and the total deformation amount is ≥ 70%.

[0012] Preferably, the annealing temperature in step (7) is 900 - 1600 °C, and the heat - preservation time is 40 - 200 min.

[0013] Furthermore, the protective atmosphere is hydrogen.

[0014] The density of the tough molybdenum alloy with Ti3AlC2 ceramic phase manufactured according to the above method reaches 99.5% or more, the particle size is 1 - 8 μm, the tensile strength at room temperature is greater than 1000 MPa, the elongation is greater than 50%, the compressive strength at 1400 °C is greater than 240 MPa, and there is a prospect of wide application in high - temperature fields.

Advantages of the Invention

[0015] Compared with the prior art, the present invention has obvious advantages and beneficial effects, and at least has the following advantages. (1) The present invention uses Ti3AlC2 particles with high melting point, high hardness, and high fracture toughness as the doping phase. After reducing the initial powder with hydrogen, it is mixed with coarse crystal grains at a certain ratio, and then hot isostatic pressing sintering is carried out. This process increases the density of the molybdenum alloy and makes the crystal grains finer. Hot press sintering can make the powder uniform and densify it more. By adjusting the amount of the mixed coarse crystal molybdenum powder, the particle size of the final material can be designed to meet the usage needs under different working conditions. (2) The doping phase Ti3AlC2 used in the present invention generates two-dimensional TiC in-situ at high temperature. 0.67 The TiC particles generated by this in-situ reaction decomposition are uniformly distributed in the molybdenum matrix, have a large specific surface area and high surface energy, promote the densification of the material, and thereby can improve the mechanical properties such as the yield strength and fracture toughness of the molybdenum alloy. The TiC 0.67 particles generated by the in-situ reaction have better thermal stability and are mainly distributed at the grain boundaries. They effectively inhibit the movement and deformation of the grain boundaries at high temperature, so the microscopic structure of the material at high temperature is more stable. The molybdenum alloy has good high-temperature strength and a high recrystallization temperature, thereby improving the performance of the molybdenum alloy in high-temperature scenarios and expanding the application range of the molybdenum alloy. 0.67 particles generated by the in-situ reaction have better thermal stability and are mainly distributed at the grain boundaries. They effectively inhibit the movement and deformation of the grain boundaries at high temperature, so the microscopic structure of the material at high temperature is more stable. The molybdenum alloy has good high-temperature strength and a high recrystallization temperature, thereby improving the performance of the molybdenum alloy in high-temperature scenarios and expanding the application range of the molybdenum alloy. (3) Through the thermoplastic deformation process, the present invention can further refine the crystal particles and improve the density and performance of the molybdenum alloy. The microscopic structure of the high-strength and tough molybdenum alloy obtained by the above method includes molybdenum crystal grains and nano-TiC 0.67 uniformly distributed in the molybdenum crystal grains. Here, the average width of the molybdenum crystal grains is 1 - 8 μm, and the average particle size of the nano-TiC 0.67 particles uniformly distributed inside the molybdenum crystal grains is 50 - 200 nm. (4) The molybdenum alloy of the present invention has excellent comprehensive performance, with high density, good uniformity, excellent performance, convenient and high-efficiency manufacturing methods, and has very good application prospects in fields such as rare earth metallurgy and aerospace.

Brief Description of the Drawings

[0016] [Figure 1] This is an SEM image of the precursor powder produced in Example 1. [Figure 2] This is an optical microscope image of the metallographic structure of the high-toughness molybdenum alloy produced in Example 1. [Figure 3] This is an optical microscope image of the metallographic structure of the high-toughness molybdenum alloy produced in Example 2. [Figure 4] This is an optical microscope image of the metallographic structure of the high-toughness molybdenum alloy produced in Example 3. [Figure 5] This is an optical microscope image of the metallographic structure of a molybdenum alloy produced as a comparative example. [Figure 6] These are the stress-strain curves for the high-toughness molybdenum alloy and pure molybdenum obtained in Examples 1-3. [Figure 7] These are the high-temperature stress-strain curves at 1400°C for the high-toughness molybdenum alloys and pure molybdenum obtained in Examples 1-3. [Modes for carrying out the invention]

[0017] To further clarify the object, technical solution, and advantages of the embodiments of the present invention, the technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Clearly, the embodiments described are some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative work based on the embodiments of the present invention fall within the technical scope of the present invention.

[0018] The manufacturing process for the tough molybdenum alloy of the Ti3AlC2 ceramic phase provided by the present invention mainly comprises the following steps (1) to (7). (1) Depending on the needs of the final product, a certain amount of MoO2 powder and Ti3AlC2 powder are weighed, dried and mixed in a dual power mixer for 12 to 32 hours, and then sieved to prepare for use. (2): The powder produced in step (1) is subjected to a hydrogen atmosphere of reducing gas at a reduction temperature of 750-1000°C and a hydrogen flow rate of 12-20 m³. 3The powder is reduced at high temperature with a reduction time of 6-24 hours and a powder laying height of <4 / 5. The reduced Ti3AlC2 ceramic phase-containing powder is then mixed with coarse crystalline Mo powder in a dual power mixer for 10-20 hours to obtain a precursor powder. (3) Depending on the dimensions required for the final product, an appropriate capsule material should be selected, and the capsule material should be subjected to ultrasonic cleaning and preheating before filling with powder. The ultrasonic cleaning temperature should be 30-60°C for 30-60 minutes, and preheating should be performed by placing the capsule material in a muffle furnace and keeping it at 500-600°C for 1-2 hours, after which it should be cooled in the furnace. (4): A certain amount of the precursor powder obtained in step (2) is weighed and loaded into the capsule processed in step (3). The capsule is loaded while vibrating with an amplitude of 3-5 mm, a vibration frequency of 280-350 times / min, and a vibration time of 15-30 min. The top and bottom of the capsule material are sealed, and the edges are welded to check for airtightness. (5) The capsules filled with powder are placed in a muffle furnace and heated to 500-600°C to remove any crystalline water present, and then degassed at high temperature for 8-20 hours using a vacuum exhaust system until the vacuum inside the capsule reaches 1 × 10⁻⁶ -3 ~1 × 10 -5 After reaching a certain temperature (pa), the exhaust port is sealed by argon arc welding, and then hot press sintering is performed at a temperature of 1300-1900°C for 4-10 hours to obtain a sintered molybdenum alloy. The microscopic structure of this sintered molybdenum alloy consists of molybdenum crystal grains and nano-TiC uniformly distributed within the alloy. 0.67 This includes, where the particle size of the molybdenum crystal grains is 5-20 μm, and nano-TiC is uniformly distributed inside the molybdenum crystal grains. 0.67 The average particle size is 50-200 nm. (6): The sintered molybdenum alloy obtained in step (5) is placed in a hydrogen-reducing atmosphere (to prevent oxidation of molybdenum, with a flow rate of 5-15 m³). 3The material is heated to 1200-1600°C in a medium ( / h), held at this temperature for 30-60 minutes, and then subjected to thermoplastic processing. The thermoplastic processing is one or a combination of rotary forging, rolling, extrusion, or drawing, with a total of 2-6 passes in the thermoplastic deformation process, a deformation of 20-30% in each pass, and a total deformation of ≥70%. (7): The molybdenum alloy billet obtained in step (6) was subjected to a flow rate of 5-15 m 3 The material is annealed in a hydrogen-reducing atmosphere at a temperature of 900-1600°C, followed by a 40-200 minute incubation period to obtain a highly dense and tough molybdenum alloy.

[0019] This invention uses lamellar Ti3AlC2 particles with high melting point, high hardness, and high fracture toughness as a doping phase. The initial powder is reduced with hydrogen and then mixed with coarse crystal grains in a certain ratio. Subsequently, hot isostatic sintering is performed, followed by hot working and heat treatment to obtain a highly dense and highly tough molybdenum alloy. Here, the secondary phase Ti3AlC2 particles are formed in situ at high temperatures as two-dimensional carbide TiC 0.67 It self-forms, and TiC is produced by this in-situ reaction decomposition. 0.67 The particles are uniformly distributed within the molybdenum matrix, TiC 0.67 The finer particles, larger specific surface area and higher surface energy, greater thermal stability, and uniform distribution of secondary phases effectively inhibit grain boundary movement and deformation at high temperatures. As a result, the microstructure of the material is more stable at high temperatures, the molybdenum alloy exhibits good high-temperature strength and a high recrystallization temperature, thereby improving the performance of the molybdenum alloy in high-temperature scenarios and expanding its application range. Ultimately, the material achieves a density of over 99.5%, a recrystallization temperature of 1600°C, a tensile strength of over 1000 MPa, an elongation of over 50%, and a compressive strength of over 240 MPa at 1400°C, comprehensively improving the mechanical properties of the molybdenum alloy.

[0020] Extensive experiments have shown that mixing coarse and fine powders can suppress the growth of the Ti3AlC2 secondary phase, and that fine TiC produced by high-temperature decomposition can be suppressed. 0.67It has been shown that this secondary phase is more abundantly distributed within the crystal grains, providing mass points for further recrystallization nucleation, and that larger secondary phases are distributed at the grain boundaries, and that, depending on their special two-dimensional lamellar structure, they improve interfacial bonding and strengthen the toughness of the molybdenum alloy.

[0021] Furthermore, the Ti3AlC2 used in step (1) has a hexagonal layered crystal structure, a purity of 99% or more, and a particle size of 2-10 μm. The molybdenum dioxide used has a particle size of 8-20 μm, and the potassium impurity content is 5-10 ppm. The commercially available coarse crystalline Mo powder used in step (2) has a particle size of 3-8 μm.

[0022] The following will provide a detailed explanation using specific examples.

[0023] Example 1 (1) Depending on the needs of the final product, 4180g of MoO2 powder and 120g of Ti3AlC2 powder were weighed, dried and mixed for 16 hours in a dual power mixer, and then sieved through a 300-mesh sieve to prepare for use. (2): The powder produced in step (1) is subjected to a hydrogen atmosphere of reducing gas at a reduction temperature of 900°C and a hydrogen flow rate of 15 m³. 3 The powder was reduced at high temperature at a rate of / h, reduction time of 18h, and a height of 2 / 3 of the powder's surface. The reduced powder was then mixed with 1700g of commercially available 3μm Mo powder in a dual-power mixer for 12h to obtain a precursor powder. (3) Depending on the dimensions required for the final product, it was necessary to select an appropriate capsule material and to perform ultrasonic cleaning and preheating treatment on the capsule material before filling it with powder. The ultrasonic cleaning temperature was 30°C for 30 minutes, and preheating involved placing the capsule material in a muffle furnace and holding it at 500°C for 1 hour, after which it was cooled in the furnace. (4): A certain amount of the precursor powder obtained in step (2) was weighed and loaded into the capsule processed in step (3). The capsule was loaded while vibrating at an amplitude of 3 mm, a vibration frequency of 320 times / min, and a vibration time of 25 min. The top and bottom of the capsule material were sealed, and the edges were welded to test for airtightness. (5) The capsule filled with powder is placed in a muffle furnace and heated to 600°C to remove any crystalline water present, and then degassed at high temperature for 16 hours using a vacuum evacuation system until the vacuum inside the capsule reaches 1 × 10⁻⁶ -3 After reaching the required temperature, the exhaust port was sealed by argon arc welding, and then hot press sintering was performed at a temperature of 1600°C for 4 hours to obtain a sintered molybdenum alloy. The microscopic structure of the sintered molybdenum alloy consists of molybdenum crystal grains and nano-TiC uniformly distributed within the alloy. 0.67 It contains molybdenum crystal grains with a particle size of 11-15 μm, and nano-TiC is uniformly distributed inside the molybdenum crystal grains. 0.67 The average particle size was 50-20 nm. (6) The sintered molybdenum alloy produced in step (5) is poured at a flow rate of 8 m 3 The material was heated to 1450°C under a hydrogen-reducing atmosphere of 1 / h, held at room temperature for 30 minutes, and then subjected to thermoplastic deformation. The thermoplastic deformation was performed by rotary forging, with a total of 5 passes, a deformation of 25% in each pass, and a total deformation of ≥76.3%. (7): The molybdenum alloy billet manufactured in step (6) is poured at a flow rate of 8 m 3 The material was annealed at a temperature of 1300°C under a hydrogen-reducing atmosphere of 1 / h, and then held at room temperature for 40 minutes to obtain a high-toughness molybdenum alloy with a density of 99.8% and a grain size of 4-6 μm.

[0024] The high-toughness molybdenum alloy produced in this embodiment had a recrystallization temperature of 1600°C. Its mechanical properties at room temperature were tested using an INSTRON-5967 universal tester, and its high-temperature compressive strength was tested using a Gleeble-1500D thermal simulation tester. The high-toughness molybdenum alloy obtained in this embodiment had a tensile strength of 1450 MPa at room temperature, an elongation of 59.7%, and a high-temperature compressive strength of 248 MPa at 1400°C, representing improvements of 208%, 70.6%, and 106.6%, respectively, compared to pure molybdenum metal.

[0025] Figure 1 is an SEM image of the precursor powder produced in step (2) of this embodiment. Two-dimensional lamellar Ti3AlC2 and molybdenum powder of various sizes are uniformly mixed.

[0026] Figure 2 shows the microstructure (metallographic image under an optical microscope) of the high-toughness molybdenum alloy produced in this embodiment. The average grain size of the molybdenum crystal grains is 4-6 μm, with large secondary phases uniformly distributed at the grain boundaries and fine secondary phases uniformly distributed within the crystal grains.

[0027] Example 2 (1) Depending on the needs of the final product, 1335 g of MoO2 powder and 90 g of Ti3AlC2 powder were weighed, dried and mixed for 16 hours in a dual power mixer, and then sieved through a 300-mesh sieve to prepare for use. (2): The powder produced in step (1) is subjected to a hydrogen atmosphere of reducing gas at a reduction temperature of 750°C and a hydrogen flow rate of 20 m³. 3 The powder was reduced at high temperature for 20 hours at a rate of 1 / h, with a reduction time of 20 hours and at half the height of the powder bed. The reduced powder was then mixed with 4000 g of coarse crystalline Mo powder in a dual-power mixer for 16 hours to obtain a precursor powder. (3) Depending on the dimensions required for the final product, it was necessary to select an appropriate capsule material and to perform ultrasonic cleaning and preheating treatment on the capsule material before filling it with powder. The ultrasonic cleaning temperature was 50°C for 30 minutes, and preheating involved placing the capsule material in a muffle furnace and holding it at 550°C for 30 minutes, after which it was cooled in the furnace. (4): A certain amount of the precursor powder obtained in step (2) was weighed and loaded into the capsule processed in step (3). The capsule was loaded while vibrating at an amplitude of 3 mm, a vibration frequency of 320 times / min, and a vibration time of 25 min. The top and bottom of the capsule material were sealed, and the edges were welded to test for airtightness. (5) The capsule filled with powder is placed in a muffle furnace and heated to 550°C to remove any crystalline water present, and then degassed at high temperature for 16 hours using a vacuum evacuation system until the vacuum inside the capsule reaches 1 × 10⁻⁶ -3After reaching a certain temperature (pa), the exhaust port was sealed by argon arc welding, and then hot press sintering was performed at a temperature of 1800°C for 5 hours to obtain a sintered molybdenum alloy. The microscopic structure of the sintered molybdenum alloy consisted of molybdenum crystal grains and nano-TiC uniformly distributed throughout the alloy. 0.67 It contains molybdenum crystal grains with a particle size of 15-20 μm, and nano-TiC is uniformly distributed inside the molybdenum crystal grains. 0.67 The average particle size ranged from 50 to 200 nm. (6): The sintered molybdenum alloy produced in step (5) is poured at a flow rate of 6 m 3 The material was heated to 1250°C under a hydrogen-reducing atmosphere of 1 / h, held at room temperature for 45 minutes, and then subjected to thermoplastic processing. The thermoplastic processing was rolling, and the total number of passes in the thermoplastic deformation process was 4, with a deformation of 30% in each pass, and a total deformation of 76%. (7): The molybdenum alloy billet manufactured in step (6) is poured at a flow rate of 6 m 3 The material was annealed at 900°C under a hydrogen-reducing atmosphere of 1 / h, and then held at room temperature for 60 minutes to obtain a high-toughness molybdenum alloy with a density of 99.7%, a grain size of 6-8 μm, and a recrystallization temperature of 1600°C.

[0028] When the mechanical properties at room temperature and high-temperature compressive strength were tested using the method of Example 1, the high-toughness molybdenum alloy obtained in this example had a tensile strength of 1290 MPa and an elongation of 57.6% at room temperature, and a high-temperature compressive strength of 275 MPa at 1400°C, which were improved by 174.5%, 64.6%, and 129.2%, respectively, compared to pure molybdenum metal.

[0029] Figure 3 shows the microstructure (optical microscope metallographic image) of the high-toughness molybdenum alloy produced in this embodiment. The average grain size of the molybdenum crystal grains is 6-8 μm, with large secondary phases uniformly distributed at the grain boundaries and fine secondary phases uniformly distributed within the crystal grains.

[0030] Example 3 (1) Depending on the needs of the final product, 2666g of MoO2 powder and 50g of Ti3AlC2 powder were weighed, dried and mixed for 16 hours in a dual-power mixer, and then sieved through a 300-mesh sieve to prepare for use. (2): The powder produced in step (1) is subjected to a hydrogen atmosphere of reducing gas at a reduction temperature of 1000°C and a hydrogen flow rate of 18 m³. 3 The powder was reduced at high temperature with a reduction time of 16 hours and a powder laying height of 4 / 5. The reduced powder was then mixed with 3000 g of coarse crystalline Mo powder in a dual power mixer for 14 hours to obtain a precursor powder. (3) Depending on the dimensions required for the final product, an appropriate capsule material had to be selected, and the capsule material had to be subjected to ultrasonic cleaning and preheating before the powder was loaded. The ultrasonic cleaning temperature was 40°C for 40 minutes, and preheating involved placing the capsule material in a muffle furnace and keeping it at 550°C for 1 hour, after which it was cooled in the furnace. (4): A certain amount of the precursor powder obtained in step (2) was weighed and loaded into the capsule processed in step (3). The capsule was loaded while vibrating at an amplitude of 3 mm, a vibration frequency of 320 times / min, and a vibration time of 25 min. The top and bottom of the capsule material were sealed, and the edges were welded to test for airtightness. (5) The capsule filled with powder is placed in a muffle furnace and heated to 650°C to remove any crystalline water present, and then degassed at high temperature for 16 hours using a vacuum evacuation system until the vacuum inside the capsule reaches 1 × 10⁻⁶ -3 ~1 × 10 -5 After reaching a temperature of 1400°C, the exhaust port was sealed by argon arc welding, and then hot press sintering was performed at a temperature of 1400°C for a sintering time of 6 hours to obtain a sintered molybdenum alloy. The microscopic structure of the sintered molybdenum alloy consists of molybdenum crystal grains and nano-TiC uniformly distributed within the alloy. 0.67 It contains molybdenum crystal grains with a particle size of 5-10 μm, and nano-TiC is uniformly distributed inside the molybdenum crystal grains. 0.67 The average particle size ranged from 50 to 200 nm. (6): The sintered molybdenum alloy produced in step (5) is poured at a flow rate of 7 m 3The material was heated to 1350°C under a hydrogen-reducing atmosphere of 1 / h, held at room temperature for 60 minutes, and then subjected to thermoplastic processing. The thermoplastic processing was rolling, and the total number of passes in the thermoplastic deformation process was 6, with a deformation amount of 30% in each pass, and a total deformation amount of 88.23%. (7): The molybdenum alloy billet manufactured in step (6) is poured at a flow rate of 7 m 3 The material was annealed at a temperature of 1300°C under a hydrogen-reducing atmosphere of 1 / h, and then held at a temperature of 50 min to obtain a high-toughness molybdenum alloy with a density of 99.9%, a grain size of 1-3 μm, and a recrystallization temperature of 1600°C.

[0031] Using the method of Example 1, the mechanical properties at room temperature and the high-temperature compressive strength were tested. The high-toughness molybdenum alloy obtained in this example had a tensile strength of 1050 MPa and an elongation of 55.8% at room temperature, and a high-temperature compressive strength of 301 MPa at 1400°C. These figures represent improvements of 123.4%, 59.4%, and 150.8%, respectively, compared to pure molybdenum metal.

[0032] Figure 4 shows the microstructure (optical microscope metallographic image) of the high-toughness molybdenum alloy produced in this embodiment. The average grain size of the molybdenum crystal grains is 1 to 3 μm, with large secondary phases uniformly distributed at the grain boundaries and fine secondary phases uniformly distributed within the crystal grains.

[0033] Comparative Example 1 In step (2), the reduced powder is not mixed with the crude crystalline molybdenum powder, but used directly as a precursor powder, and the process from step (3) to step (7) is carried out, with the other steps being the same as in Example 1, to obtain a molybdenum alloy product. The density and particle size of the molybdenum alloy produced according to the test method of Example 1 are tested, and its density is 98.5%, the particle size of the molybdenum crystal grains is 10-20 μm, and nano-TiC is uniformly distributed inside the molybdenum crystal grains. 0.67The average particle size was 0.5-3 μm, the tensile strength at room temperature was 820 MPa, the elongation was 49.8%, and the high-temperature compressive strength at 1400°C was 199 MPa. Comparing the comparative example with the example, it was explained that after mixing the reduced powder with coarse-grained molybdenum powder and then performing the subsequent process, the molybdenum grain size of the molybdenum alloy produced was smaller and the density was higher.

[0034] Figure 5 shows the microstructure (metallographic image under an optical microscope) of the molybdenum alloy produced in the comparative example. The average grain size is 10-20 μm.

[0035] Figure 6 shows the stress-strain curves of the high-toughness molybdenum alloys and pure molybdenum obtained in Examples 1 to 3. The strengths of the molybdenum alloys obtained by the different processes in the three examples differ slightly, but overall they are higher than the strength of pure molybdenum.

[0036] Figure 7 shows the high-temperature stress-strain curves at 1400°C for the high-toughness molybdenum alloys and pure molybdenum obtained in Examples 1-3. The compressive strength at 1400°C of the high-toughness molybdenum alloys obtained in the three examples was significantly improved compared to pure molybdenum.

[0037] The above are merely embodiments of the present invention and do not limit the present invention to any form. The present invention can take other forms based on the above structure and function, but these will not be listed one by one. Therefore, those skilled in the art will know that any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the technical solutions of the present invention, fall within the scope of the technical solutions of the present invention.

Claims

1. Ti ３ AlC ２ A manufacturing process for tough molybdenum alloys with a ceramic phase, (1) A certain amount of MoO depending on the needs of the final product. ２ Powder and Ti ３ AlC ２ The process involves weighing the powder, drying and mixing it in a dual-power mixer for 12 to 32 hours, and then sieving it to prepare it for use. (2) The powder produced in step (1) is subjected to a hydrogen atmosphere at a reduction temperature of 750 to 1000°C and a hydrogen flow rate of 12 to 20 m³. ３ / h, reduction time 6-24h, high-temperature reduction, reduced Ti ３ AlC ２ The process involves a step of obtaining a precursor powder by mixing a ceramic phase-containing powder with Mo powder having a particle size of 3 to 8 μm in a constant ratio in a dual-power mixer for 10 to 20 hours, and (3) Select an appropriate capsule material according to the dimensions required for the final product, and perform ultrasonic cleaning and preheating of the capsule material before loading the powder, (4): A certain amount of the precursor powder obtained in step (2) is weighed, loaded into the capsule material processed in step (3), loaded while vibrating, the top and bottom of the capsule material are sealed, the edges are welded and the airtightness is checked. (5): Put the capsule filled with powder into a muffler furnace, heat it to 500-600 °C to remove the possible crystal water, degas it for 8-20 h at the same temperature as the heating temperature of the muffler furnace using a vacuum exhaust system, and when the vacuum degree in the capsule reaches 1×10 －３ ~1×10 －５ Pa, seal and weld the exhaust port by argon arc welding, and then perform hot press sintering to obtain a sintered molybdenum alloy; (6) The sintered molybdenum alloy obtained in step (5) is poured at a flow rate of 5 to 15 m ３ The steps include heating to 1300-1600°C under a hydrogen atmosphere of 1 / h, holding the temperature for 30-60 min, and then performing thermoplastic processing to obtain a molybdenum alloy billet, (7) The Ti is characterized by comprising the step of annealing the molybdenum alloy billet obtained in step (6) in a hydrogen atmosphere to finally obtain a highly dense and highly tough molybdenum alloy. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

2. Ti used in step (1) ３ AlC ２ The Ti according to claim 1 is characterized in that it has a layered structure, a purity of 99% or more, a particle size of 2 to 10 μm, a particle size of molybdenum dioxide used of 8 to 20 μm, and a potassium impurity content of 5 to 10 ppm. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

3. The Ti according to claim 1 is characterized in that the ultrasonic cleaning temperature in step (3) is 30 to 60°C, the time is 30 to 60 min, the preheating treatment is performed by placing the capsule material in a muffle furnace and keeping it at 500 to 600°C for 1 to 2 hours, and after the heating is complete, cooling in the furnace. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

4. The Ti according to claim 1, characterized in that the vibration amplitude during powder charging in step (4) is 3 to 5 mm, the vibration frequency is 280 to 350 times / min, and the vibration time is 15 to 30 min. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

5. In step (5), the hot press sintering temperature is 1300 to 1900°C, the sintering time is 4 to 10 hours, and the microscopic structure of the sintered molybdenum alloy is molybdenum crystal grains and nano-TiC uniformly distributed within the alloy. ０．６７ It contains and the molybdenum crystal grain size is 5 to 20 μm, and TiC ０．６７ The Ti according to claim 1, characterized in that the average particle size is 50 to 200 nm. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

6. The thermoplastic processing in step (6) is one or a combination of rotary forging, rolling, extrusion, or drawing, and in the thermoplastic processing, the total number of passes is 2 to 6, the amount of deformation in each pass is 20 to 30%, and the total amount of deformation is ≥ 70%, as described in claim 1. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

7. The Ti according to claim 1, characterized in that the annealing temperature in step (7) is 900 to 1600°C and the holding time is 40 to 200 mins. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

8. The Ti according to any one of claims 1 to 7, characterized in that the density of the molybdenum alloy produced in step (7) is 99.5% or more. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

9. The Ti according to any one of claims 1 to 7, characterized in that the molybdenum alloy produced in step (7) has a tensile strength greater than 1000 MPa at room temperature, an elongation greater than 50%, and a compressive strength greater than 240 MPa at 1400°C. ３ AlC ２ Manufacturing process for tough molybdenum alloys with a ceramic phase.

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