Method for preparing blending structure reinforced NiAl-based composite material through thermal deformation

Abstract

The invention discloses a method for preparing a blending structure reinforced NiAl-based composite material through thermal deformation, and relates to a method for preparing a nickel-aluminum composite material. The invention aims to solve the problem that the existing NiAl alloy is single in structure and poor in deformation resistance, so that the toughness is poor. The method comprises the following steps: 1, weighing Ni, Al, V, Mo, Zr and B powder; 2, carrying out staged ball milling, and introducing oxygen in the final stage; 3, applying pressure; 4, heating; and 5, carrying out thermal deformation to obtain the NiAl-based composite material with the reinforced blending structure. According to the invention, a blending structure in which recrystallized fine grain structures are continuously distributed along the grain boundary is formed by using a grain boundary arch nucleation recrystallization principle, and the structure morphology and structure can be improved under the condition that other materials are not added, so that the material performance is greatly improved. According to the preparation method, the NiAl-based composite material with the reinforced blending structure can be obtained.

Description

Technical Field

[0001] This invention relates to a method for preparing nickel-aluminum composite materials. Background Technology

[0002] With the continuous development of my country's aerospace and other cutting-edge industries, the requirements for high-temperature structural materials are becoming increasingly stringent. Currently, nickel-based superalloys are the most widely used in the aerospace field, but their high density makes them insufficient for lightweight structural requirements, and their operating temperature range of 650-1000℃ does not meet ultra-high temperature requirements. Therefore, there is an urgent need to find and develop materials with high melting points, low specific gravity, and excellent mechanical properties. Compared with traditional metals, the covalent bonds in intermetallic compounds enhance the interatomic bonding force and stabilize the chemical bonds, thus possessing advantages such as high melting points and wear resistance, making them one of the most promising high-temperature structural materials.

[0003] Compared to other intermetallic compounds, NiAl intermetallic compounds exhibit long-range ordered B2 structures, resulting in significant performance advantages, such as a density of 5.86 g / cm³. 3 It has only 2 / 3 the strength of nickel-based superalloys, a melting point as high as 1650℃, a high Young's modulus, a low ductile-brittle transition temperature, and a service temperature as high as 1200℃. Furthermore, it exhibits excellent oxidation resistance and wear resistance, making it a preferred material to replace nickel-based superalloys. However, its poor room-temperature plasticity and low high-temperature strength severely hinder its practical application. Although researchers have attempted various methods to improve its properties, the resulting materials have relatively simple structures and poor resistance to deformation, making it difficult to fundamentally improve the material's strength. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of poor strength and toughness caused by the simple structure and weak deformation resistance of existing NiAl alloys, and to provide a method for preparing NiAl-based composite materials with a harmonized structure through hot deformation.

[0005] A method for preparing harmonized structure reinforced NiAl-based composite materials by hot deformation is specifically carried out according to the following steps:

[0006] 1. Weigh out Ni, Al, V, Mo, Zr and B powders, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar and add grinding balls;

[0007] The mass ratio of Ni, Al, V, Mo, Zr and B powder mentioned in step one is (5.753~6.166):(2.699~2.888):(0~0.6):(0~0.4):0.296:0.1;

[0008] 2. Under the protection of argon atmosphere, ball milling is carried out in stages. In the last ball milling stage, a certain amount of oxygen is introduced and two powders with different particle sizes are screened out.

[0009] 3. After mixing two powders with different particle sizes, apply pre-pressure, maintain pressure, and after the powder is compacted, release the pressure and draw a vacuum.

[0010] IV. Heat to 1350℃~1450℃, maintain the temperature and apply continuous pressure, and cool with the furnace to obtain the original billet of NiAl-based composite material;

[0011] 5. The original NiAl-based composite material blank is heated to 1150℃~1250℃ and held at that temperature, and then hot-deformed at a certain rate. Finally, the hot-deformed blank is water-cooled to obtain a NiAl-based composite material with a harmonized structure reinforcement.

[0012] The thermal deformation amount mentioned in step five is 10%~40%.

[0013] Advantages of this invention:

[0014] I. This invention discloses a method for preparing NiAl-based composite materials with a harmonized structure through hot deformation. Utilizing the grain boundary bowing nucleation and recrystallization principle, a harmonized structure is formed where recrystallized fine grains are continuously distributed along the grain boundaries. This improves the microstructure and structure without adding other materials, thereby significantly enhancing material properties. It effectively addresses the problem in existing research where the low density, room temperature plasticity, and high temperature strength of NiAl are difficult to balance, thus severely hindering its application. This method yields NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite materials with good formability, excellent mechanical properties, and a harmonized structure, showing a significant improvement over pure NiAl.

[0015] II. The pure NiAl intermetallic compound prepared by this invention has a room temperature ultimate compressive strength of 1208 MPa, a compression limit deformation of 25.5%, and a compressive yield strength of 95 MPa at 1000℃. In contrast, the NiAl-based composite material with harmonized structural reinforcement (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) prepared by this invention has a room temperature ultimate compressive strength of 2105 MPa-2274 MPa, a compression limit deformation of 28.9%-35.1%, and a compressive yield strength of 201 MPa-220 MPa at 1000℃. Therefore, it can be seen that the mechanical properties of the NiAl-based composite material with harmonized structural reinforcement (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) prepared by this invention are significantly improved compared to pure NiAl.

[0016] The present invention provides a NiAl-based composite material with a harmonized structure reinforcement. Attached Figure Description

[0017] Figure 1 EBSD image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 1;

[0018] Figure 2 TEM image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 1;

[0019] Figure 3 EBSD image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 2;

[0020] Figure 4 The image shows the EBSD diagram of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 3. Detailed Implementation

[0021] Specific Implementation Method 1: This implementation method is a method for preparing NiAl-based composite materials with harmonized structure through hot deformation, specifically carried out according to the following steps:

[0022] 1. Weigh out Ni, Al, V, Mo, Zr and B powders, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar and add grinding balls;

[0023] The mass ratio of Ni, Al, V, Mo, Zr and B powder mentioned in step one is (5.753~6.166):(2.699~2.888):(0~0.6):(0~0.4):0.296:0.1;

[0024] 2. Under the protection of argon atmosphere, ball milling is carried out in stages. In the last ball milling stage, a certain amount of oxygen is introduced and two powders with different particle sizes are screened out.

[0025] 3. After mixing two powders with different particle sizes, apply pre-pressure, maintain pressure, and after the powder is compacted, release the pressure and draw a vacuum.

[0026] IV. Heat to 1350℃~1450℃, maintain the temperature and apply continuous pressure, and cool with the furnace to obtain the original billet of NiAl-based composite material;

[0027] 5. The original NiAl-based composite material blank is heated to 1150℃~1250℃ and held at that temperature, and then hot-deformed at a certain rate. Finally, the hot-deformed blank is water-cooled to obtain a NiAl-based composite material with a harmonized structure reinforcement.

[0028] The thermal deformation amount mentioned in step five is 10%~40%.

[0029] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: in step one, Ni, Al, V, Mo, Zr, and B powders are weighed in a vacuum glove box; the total mass ratio of the grinding ball to the Ni, Al, V, Mo, Zr, and B powders in step one is (10~12):1. Other steps are the same as in Specific Implementation Method One.

[0030] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the Ni powder in step one has a particle size of 5μm~20μm and a purity greater than 99.5%; the Al powder in step one has a particle size of 5μm~50μm and a purity greater than 99.9%. Other steps are the same as in Specific Implementation Method One or Two.

[0031] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the particle size of the V powder mentioned in step one is 5μm~50μm, and the purity is greater than 99.9%; the particle size of the Mo powder mentioned in step one is 10μm~50μm, and the purity is greater than 99.9%; the particle size of the Zr powder mentioned in step one is 5μm~50μm, and the purity is greater than 99.9%; the particle size of the B powder mentioned in step one is 10μm~50μm, and the purity is greater than 99.9%. The other steps are the same as in Specific Implementation Methods One to Three.

[0032] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the diameter of the grinding ball mentioned in step one is 8mm or 6mm; the grinding jar mentioned in step one is made of stainless steel and has a volume of 250mL to 500mL. Other steps are the same as in Specific Implementation Methods One to Four.

[0033] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One through Five in that: In step two, under argon atmosphere protection, the ball milling is carried out in stages. The specific method for introducing a quantitative amount of oxygen and screening out two different particle sizes in the final ball milling stage is as follows: The ball milling jar is evacuated, then high-purity argon is introduced, and this process is repeated 3 to 5 times. The ball milling jar is then sealed. The sealed jar is placed on a ball mill, and ball milling is first performed at 300 r / min to 350 r / min for 2 to 3 hours, and then at 550 r / min to 650 r / min for 1.5 hours. After evacuating the ball mill jar again for 3 hours, a measured amount of oxygen is introduced into the jar. The volume ratio of oxygen to the mass of the mixed metal powder is (100mL~110mL):(9.5g~10g). The ball mill is then carried out at 450r / min~500r / min for 5 hours~6 hours. Mixed metal powder with a particle size of 100μm is screened out. The remaining mixed metal powder is then ball milled for another 1 hour~3 hours to screen out mixed metal powder with a particle size of 30μm. During the ball milling process, cooling is performed for 2 minutes~5 minutes after every 10 minutes~20 minutes of ball milling. Other steps are the same as in specific embodiments one to five.

[0034] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: the two different particle sizes of powders mentioned in step three are metal powder with a particle size of 100 μm and metal powder with a particle size of 30 μm; the mass ratio of the metal powder with a particle size of 100 μm to the metal powder with a particle size of 30 μm is (40~60):(60~40); the mixing mentioned in step three is ball milling at 300 r / min~350 r / min for 2 h~3 h. Other steps are the same as in Specific Implementation Methods One to Six.

[0035] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step three, the two powders with different particle sizes are mixed and transferred into a high-strength graphite mold. The high-strength graphite mold is then placed in a vacuum hot-pressing sintering furnace, where a pre-pressure of 5MPa to 10MPa is applied through a pressure head and held for 30 to 60 minutes. After the powder is compacted, the pressure is released and a vacuum is drawn. The flexural strength of the high-strength graphite mold is greater than 60MPa. Other steps are the same as in Specific Implementation Methods One to Seven.

[0036] Specific Implementation Method Nine: The difference between this implementation method and Specific Implementation Methods One through Eight is that in step four, the vacuum degree needs to reach 1×10⁻⁶. -4After applying a pressure of MPa, the mold is heated at a rate of 15℃ / min to 30℃ / min until it reaches 1350℃ to 1450℃. This temperature is then held for 30 to 60 minutes. During the holding period, a pressure of 40MPa to 50MPa is continuously applied. Heating is stopped after the holding period, and the mold is cooled with the furnace. Pressure is released when the temperature drops to 800℃, and the diffusion pump is turned off when the temperature drops below 400℃. The mold is then allowed to cool naturally to below 80℃. The high-strength graphite mold is then removed, yielding the original NiAl-based composite material blank. Other steps are the same as in specific embodiments one through eight.

[0037] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One through Nine in that: the heating rate in step five is 10℃ / s to 15℃ / s; the holding time in step five is 1 min to 3 min; and the rate of thermal deformation in step five is 1×10⁻⁶. -2 s -1 ~1×10 -3 s -1 The water cooling temperature described in step five is 20℃~25℃. The other steps are the same as those in specific embodiments one through nine.

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

[0039] Example 1: A method for preparing a harmonized structure reinforced NiAl-based composite material by hot deformation, characterized in that the method is specifically carried out according to the following steps:

[0040] 1. Weigh Ni, Al, V, Mo, Zr and B powders in a vacuum glove box, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar and add grinding balls;

[0041] The mass ratio of Ni, Al, V, Mo, Zr and B powder mentioned in step one is 5.753:2.699:0.6:0.4:0.296:0.1;

[0042] The Ni powder mentioned in step one has a particle size of 5μm~20μm and a purity greater than 99.5%.

[0043] The Al powder mentioned in step one has a particle size of 5μm~50μm and a purity greater than 99.9%;

[0044] The V powder mentioned in step one has a particle size of 5μm~50μm and a purity greater than 99.9%;

[0045] The Mo powder mentioned in step one has a particle size of 10μm~50μm and a purity greater than 99.9%;

[0046] The Zr powder mentioned in step one has a particle size of 5μm~50μm and a purity greater than 99.9%;

[0047] The particle size of powder B mentioned in step one is 10μm~50μm, and the purity is greater than 99.9%;

[0048] The total mass ratio of the grinding balls to Ni, Al, V, Mo, Zr and B powders mentioned in step one is 10:1;

[0049] The grinding balls mentioned in step one are a mixture of grinding balls with diameters of 8mm and 6mm; the mass ratio of the 8mm diameter balls to the 6mm diameter balls is 6:4.

[0050] The ball mill jar mentioned in step one is made of stainless steel and has a volume of 250mL;

[0051] 2. Evacuate the ball mill jar, then introduce high-purity argon gas, repeating this process three times, and then seal the ball mill jar. Place the sealed ball mill jar on a ball mill, first ball milling at 350 r / min for 3 hours, then ball milling at 550 r / min for 2 hours. Finally, evacuate the ball mill jar again and introduce a fixed amount of oxygen into the jar. The volume ratio of oxygen to the mass of the mixed metal powder is 105.7 mL: 9.85 g, and ball mill at 450 r / min for 5 hours. Screen out the mixed metal powder with a particle size of 100 μm. Continue ball milling the remaining mixed metal powder for 2 hours and screen out the mixed metal powder with a particle size of 30 μm.

[0052] During the ball milling process, the ball milling process lasts for 10 minutes, followed by a 2-minute cooling period.

[0053] 3. Mix the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm in a ball mill jar at a low speed to obtain a powder with uniformly mixed particle sizes.

[0054] The mass ratio of the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm mentioned in step three is 50:50.

[0055] The low-rate mixing described in step three involves ball milling at 300 r / min for 3 hours;

[0056] 4. Transfer the powder of two uniformly mixed particle sizes into a high-strength graphite mold, and place the high-strength graphite mold into a vacuum hot pressing sintering furnace. Apply pre-pressure through the pressure head, maintain pressure, release pressure and vacuum after the powder is compacted.

[0057] The flexural strength of the high-strength graphite mold mentioned in step four is greater than 60 MPa;

[0058] In step four, a pre-pressure of 10 MPa is applied, and the pressure is maintained for 60 minutes.

[0059] 5. After the vacuum degree reaches a certain value, heat the mold at a certain heating rate. After the temperature reaches 1400℃, keep it at that temperature for a period of time, and continue to apply pressure during the heat preservation process.

[0060] In step five, the vacuum level is expected to reach 1×10⁻⁶. -4 After applying MPa, the mold is heated at a heating rate of 30℃ / min. Once the temperature reaches 1400℃, it is held at that temperature for 30 minutes, during which a pressure of 50MPa is continuously applied.

[0061] 6. After the heat preservation is completed, stop heating and let the furnace cool. When the temperature drops to 800℃, release the pressure. When the temperature drops to below 400℃, turn off the diffusion pump and let it cool naturally to below 80℃. Take out the high-strength graphite mold to obtain the original billet of NiAl-based composite material.

[0062] 7. The original NiAl-based composite material blank is heated to 1200℃ at a heating rate of 10℃ / s and held for 2 minutes. Then, it is thermally deformed at a certain rate. Finally, the thermally deformed blank is water-cooled to obtain a NiAl-based composite material with a harmonized structure reinforcement.

[0063] The thermal deformation amount mentioned in step five is 40%;

[0064] The rate of thermal deformation mentioned in step five is 1×10 -3 s -1 The water cooling temperature mentioned in step five is 20℃.

[0065] Figure 1 EBSD image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 1;

[0066] from Figure 1(a) and (b) reveal that numerous fine grain boundaries, predominantly HAGB, are formed at the initial grain boundaries. These fine grain boundaries, continuously distributed along the grain boundaries, form a unique harmonic structure at the mesoscale. This structure is primarily due to the continuous increase in dislocation density within the grain boundaries and grains as deformation progresses. When deformation exceeds the critical strain, more slip systems within the grains are activated, and dislocations move through slip and climb mechanisms. Positive and negative dislocations cancel each other out, while similar dislocations merge, resulting in dynamic recovery. At grain boundaries, due to the increased dislocation density, a segment of a large-angle grain boundary arches outward towards the side with higher dislocation density and finer cellular structure, forming a small dislocation-free region and reducing the system's free energy. This region then becomes a recrystallization nucleus and undergoes dynamic recrystallization; this recrystallization method is called grain boundary arching nucleation recrystallization. Furthermore, the deformation zone formed near ceramic particles also promotes dynamic recrystallization during hot deformation, a process known as particle-induced nucleation recrystallization. In summary, due to the combined effect of NiAl's strong recovery ability and the ceramic particles' ability to effectively promote recrystallization, dynamic recovery dominates within the grains, while dynamic recrystallization dominates at the grain boundaries. This results in a unique and harmonious structure in which the recrystallized fine-grained structure is continuously distributed along the grain boundaries.

[0067] Figure 2 TEM image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 1;

[0068] Depend on Figure 2 It can be seen that after thermal deformation, stacking faults are generated at the boundaries of some fine grains and inside the large grains, and together with the V(Mo) phase around the grains, they surround the grains, or as... Figure 2 As shown in (d), the V(Mo) phase directly encapsulating the grains preferentially deforms and generates a large number of dislocations. Both of these methods result in unique grain structures that make further deformation difficult, effectively improving the material's strength.

[0069] The NiAl-based composite material (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) with harmonized structure reinforcement prepared in Example 1 has a room temperature compressive strength of 2274 MPa, a compressive deformation of 28.9%, and a compressive yield strength of 220 MPa at 1000 °C.

[0070] Example 2: The difference between this example and Example 1 is that the thermal deformation amount mentioned in step five is 10%. The other steps and parameters are the same as in Example 1.

[0071] The NiAl-based composite material (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) with harmonized structural reinforcement prepared in Example 2 has a room temperature compressive strength of 2105 MPa, a compressive deformation of 35.1%, and a compressive yield strength of 201 MPa at 1000 °C.

[0072] Example 3: The difference between this example and Example 1 is that the heat deformation amount mentioned in step five is 20%.

[0073] The other steps and parameters are the same as in Example 1.

[0074] The NiAl-based composite material (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) with harmonized structural reinforcement prepared in Example 3 has a room temperature compressive strength of 2185 MPa, a compressive deformation of 32.5%, and a compressive yield strength of 209 MPa at 1000 °C.

[0075] Comparative Example 1: The preparation method of NiAl intermetallic compound is carried out according to the following steps:

[0076] 1. Weigh Ni and Al powders in a vacuum glove box, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar, and then add grinding balls;

[0077] The mass ratio of Ni to Al powder mentioned in step one is 6.851:3.149;

[0078] The mass ratio of the grinding balls to the mixed metal powder in step one is 10:1;

[0079] The Ni powder mentioned in step one has a particle size of 8 μm and a purity greater than 99.5%.

[0080] The Al powder mentioned in step one has a particle size of 10 μm and a purity greater than 99.9%.

[0081] The grinding balls mentioned in step one have a diameter of 8mm or 6mm; the mass ratio of the 8mm diameter balls to the 6mm diameter balls is 6:4.

[0082] The ball mill jar mentioned in step one is made of stainless steel and has a volume of 250mL;

[0083] 2. Evacuate the ball mill jar, then introduce high-purity argon gas, repeat the operation 3 times, and then seal the ball mill jar. Place the sealed ball mill jar on the ball mill and first ball mill at 350 r / min for 3 hours. After the original powder is mixed evenly, ball mill at 550 r / min for 2 hours. During this process, the powder and the grinding balls collide violently. Under the high-energy impact, the powder continuously aggregates to form large-sized mixed powder particles. Then ball mill at 450 r / min for 5 hours and screen out the mixed metal powder with a particle size of 100 μm. Continue to ball mill the remaining mixed metal powder for 2 hours and screen out the mixed metal powder with a particle size of 30 μm.

[0084] In step two, after each 10-minute ball milling process, the ball is cooled for 2 minutes.

[0085] 3. Mix the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm in a ball mill jar at a low speed to obtain a powder with uniformly mixed particle sizes.

[0086] The mass ratio of the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm mentioned in step three is 50:50.

[0087] The low-rate mixing described in step three involves ball milling at 300 r / min for 3 hours;

[0088] 4. Transfer the powder of two uniformly mixed particle sizes into a high-strength graphite mold, and place the high-strength graphite mold into a vacuum hot pressing sintering furnace. Apply pre-pressure through the pressure head, maintain pressure, release pressure and vacuum after the powder is compacted.

[0089] The flexural strength of the high-strength graphite mold mentioned in step four is greater than 60 MPa;

[0090] In step four, a pre-pressure of 10 MPa is applied, and the pressure is maintained for 60 minutes.

[0091] 5. After the vacuum degree reaches a certain value, heat the mold at a certain heating rate. After the temperature reaches 1400℃, keep it at that temperature for a period of time, and continue to apply pressure during the heat preservation process.

[0092] In step five, the vacuum level is expected to reach 1×10⁻⁶. -4 After applying MPa, the mold is heated at a heating rate of 30℃ / min. Once the temperature reaches 1400℃, it is held at that temperature for 30 minutes, during which a pressure of 50MPa is continuously applied.

[0093] 6. After the heat preservation is completed, stop heating and let the furnace cool. When the temperature drops to 800℃, release the pressure. When the temperature drops below 400℃, turn off the diffusion pump and let it cool naturally to below 80℃. Remove the high-strength graphite mold to obtain the NiAl intermetallic compound.

[0094] The pure NiAl intermetallic compound prepared in Comparative Example 1 has a room temperature ultimate compressive strength of 1208 MPa, a compression limit deformation of 25.5%, and a compressive yield strength of 95 MPa at 1000 °C. In contrast, the NiAl-based composite material with harmonized structure reinforcement (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) prepared in Example 1 has a room temperature ultimate compressive strength of 2274 MPa, a compression limit deformation of 28.9%, and a compressive yield strength of 220 MPa at 1000 °C. Therefore, it can be seen that the mechanical properties of the NiAl-based composite material with harmonized structure reinforcement (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) prepared in Example 1 are significantly improved compared with pure NiAl.

[0095] Comparative Example 2: The preparation method of NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material is carried out according to the following steps:

[0096] 1. Weigh Ni, Al, V, Mo, Zr and B powders in a vacuum glove box, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar, and then add grinding balls;

[0097] The mass ratio of Ni, Al, V, Mo, Zr and B powders mentioned in step one is 5.753:2.699:0.6:0.4:0.296:0.1;

[0098] The mass ratio of the grinding balls to the mixed metal powder in step one is 10:1;

[0099] The Ni powder mentioned in step one has a particle size of 8 μm and a purity greater than 99.5%.

[0100] The Al powder mentioned in step one has a particle size of 10 μm and a purity greater than 99.9%.

[0101] The V powder mentioned in step one has a particle size of 30 μm and a purity greater than 99.9%.

[0102] The Mo powder mentioned in step one has a particle size of 30 μm and a purity greater than 99.9%.

[0103] The Zr powder mentioned in step one has a particle size of 30 μm and a purity greater than 99.9%.

[0104] The particle size of powder B mentioned in step one is 10 μm, and the purity is greater than 99.9%.

[0105] The grinding balls mentioned in step one have a diameter of 8mm or 6mm; the mass ratio of the 8mm diameter balls to the 6mm diameter balls is 6:4.

[0106] The ball mill jar mentioned in step one is made of stainless steel and has a volume of 250mL;

[0107] 2. Evacuate the ball mill jar, then introduce high-purity argon gas, repeat the operation 3 times, and then seal the ball mill jar. Place the sealed ball mill jar on the ball mill, and first ball mill at 350 r / min for 3 hours. After the original powder is mixed evenly, ball mill at 550 r / min for 2 hours. During this process, the powder and the grinding balls collide violently, and the powder continuously aggregates under high-energy impact to form large-sized mixed powder particles. Finally, evacuate the ball mill jar again, introduce a certain amount of oxygen into the jar, and ball mill at 450 r / min for 5 hours. Screen out the mixed metal powder with a particle size of 100 μm. Continue to ball mill the remaining mixed metal powder for 2 hours and screen out the mixed metal powder with a particle size of 30 μm.

[0108] In step two, after each 10-minute ball milling process, the ball is cooled for 2 minutes.

[0109] In step two, the volume ratio of a fixed amount of oxygen introduced into the container to the mass ratio of the mixed metal powder is 105.7 mL: 9.85 g.

[0110] 3. Mix the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm in a ball mill jar at a low speed to obtain a powder with uniformly mixed particle sizes.

[0111] The mass ratio of the mixed metal powder with a particle size of 100 μm and the mixed metal powder with a particle size of 30 μm mentioned in step three is 50:50.

[0112] The low-rate mixing described in step three involves ball milling at 300 r / min for 3 hours;

[0113] 4. Transfer the powder of two uniformly mixed particle sizes into a high-strength graphite mold, and place the high-strength graphite mold into a vacuum hot pressing sintering furnace. Apply pre-pressure through the pressure head, maintain pressure, release pressure and vacuum after the powder is compacted.

[0114] The flexural strength of the high-strength graphite mold mentioned in step four is greater than 60 MPa;

[0115] In step four, a pre-pressure of 10 MPa is applied, and the pressure is maintained for 60 minutes.

[0116] 5. After the vacuum degree reaches a certain value, heat the mold at a certain heating rate. After the temperature reaches 1400℃, keep it at that temperature for a period of time, and continue to apply pressure during the heat preservation process.

[0117] In step five, the vacuum level is expected to reach 1×10⁻⁶. -4After applying MPa, the mold is heated at a heating rate of 30℃ / min. Once the temperature reaches 1400℃, it is held at that temperature for 30 minutes, during which a pressure of 50MPa is continuously applied.

[0118] 6. After the heat preservation is completed, stop heating and let the furnace cool. When the temperature drops to 800℃, release the pressure. When the temperature drops below 400℃, turn off the diffusion pump and let it cool naturally to below 80℃. Take out the high-strength graphite mold to obtain the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material.

[0119] The NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material prepared in Comparative Example 2 has a room temperature compressive strength of 2030 MPa, a compressive deformation of 39.5%, and a compressive yield strength of 190 MPa at 1000 °C. In contrast, the NiAl-based composite material with harmonized structural reinforcement prepared in Example 1 (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) has a room temperature compressive strength of 2274 MPa, a compressive deformation of 28.9%, and a compressive yield strength of 220 MPa at 1000 °C. Therefore, the mechanical properties of the NiAl-based composite material with harmonized structural reinforcement prepared in Example 1 (NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material) are significantly improved compared to the original NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material.

[0120] Figure 3 EBSD image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 2;

[0121] Figure 4 EBSD image of the NiAl(B)-V(Mo)-(Al2O3+ZrO2) composite material with harmonic structure reinforcement prepared in Example 3;

[0122] Combination Figure 1 , Figure 3 , Figure 4Comprehensive analysis reveals that when the amount of hot deformation is small, partial dislocations begin to form within the grains, resulting in dislocation tangles and dislocation cells. Dynamic recrystallization has not yet occurred or only nucleates at a small number of grain boundaries. As the amount of deformation increases, the stored energy continuously improves, providing sufficient driving force for recrystallization. Dynamic recrystallization begins near the original grain boundaries, deformation zones, or second-phase particles, forming fine, undistorted new grains. When the amount of deformation is sufficiently large, the dynamic recrystallization process tends to be complete, and the original coarse grains are completely replaced by fine, equiaxed recrystallized grains, resulting in a more uniform and finer microstructure. However, a large number of dislocations also accumulate within the microstructure at the same time. In summary, an appropriate amount of hot deformation is beneficial for improving material properties.

Claims

1. A method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation, characterized in that... The method is specifically implemented according to the following steps:

1. Weigh out Ni, Al, V, Mo, Zr and B powders, mix them evenly to obtain mixed metal powder; put the mixed metal powder into a ball mill jar and add grinding balls; The mass ratio of Ni, Al, V, Mo, Zr and B powder mentioned in step one is (5.753~6.166):(2.699~2.888):(0~0.6):(0~0.4):0.296:0.1; 2. Under the protection of argon atmosphere, ball milling is carried out in stages. In the last ball milling stage, a certain amount of oxygen is introduced and two powders with different particle sizes are screened out.

3. After mixing two powders with different particle sizes, apply pre-pressure, maintain pressure, and after the powder is compacted, release the pressure and draw a vacuum. IV. Heat to 1350℃~1450℃, maintain the temperature and apply continuous pressure, and cool with the furnace to obtain the original billet of NiAl-based composite material; 5. The original NiAl-based composite material blank is heated to 1150℃~1250℃ and held at that temperature, and then hot-deformed at a certain rate. Finally, the hot-deformed blank is water-cooled to obtain a NiAl-based composite material with a harmonized structure reinforcement. The thermal deformation amount mentioned in step five is 10%~40%.

2. The method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... In step one, Ni, Al, V, Mo, Zr and B powders are weighed in a vacuum glove box; the total mass ratio of the grinding ball to the Ni, Al, V, Mo, Zr and B powders in step one is (10~12):

1.

3. The method for preparing a harmonized structure reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... The Ni powder mentioned in step one has a particle size of 5μm to 20μm and a purity greater than 99.5%; the Al powder mentioned in step one has a particle size of 5μm to 50μm and a purity greater than 99.9%.

4. The method for preparing a harmonized structure reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... The V powder mentioned in step one has a particle size of 5μm~50μm and a purity greater than 99.9%; the Mo powder mentioned in step one has a particle size of 10μm~50μm and a purity greater than 99.9%; the Zr powder mentioned in step one has a particle size of 5μm~50μm and a purity greater than 99.9%; the B powder mentioned in step one has a particle size of 10μm~50μm and a purity greater than 99.9%.

5. The method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... The diameter of the grinding balls mentioned in step one is one or both of 8mm and 6mm; the grinding jar mentioned in step one is made of stainless steel and has a volume of 250mL~500mL.

6. The method for preparing a harmonized structure reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... In step two, under an argon atmosphere, ball milling is performed in stages. The specific method for introducing a measured amount of oxygen and separating two powders of different particle sizes in the final ball milling stage is as follows: The ball mill jar is evacuated, then high-purity argon is introduced, and this process is repeated 3-5 times. The jar is then sealed. The sealed jar is placed on a ball mill, and ball milling is first performed at 300-350 rpm for 2-3 hours, then at 550-650 rpm for 1.5-3 hours. Finally, the ball mill jar is evacuated again. After emptying, a fixed amount of oxygen is introduced into the container, with the volume ratio of oxygen to the mass ratio of the mixed metal powder being (100mL~110mL):(9.5g~10g). The mixture is then ball-milled at 450r / min~500r / min for 5h~6h. Mixed metal powder with a particle size of 100μm is screened out. The remaining mixed metal powder is then ball-milled for another 1h~3h, and mixed metal powder with a particle size of 30μm is screened out. During the ball milling process, the mixture is cooled for 2min~5min after every 10min~20min of ball milling.

7. The method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... The two different particle sizes of powder mentioned in step three are metal powder with a particle size of 100 μm and metal powder with a particle size of 30 μm; the mass ratio of the metal powder with a particle size of 100 μm to the metal powder with a particle size of 30 μm is (40~60):(60~40); the mixing mentioned in step three is ball milling at 300 r / min~350 r / min for 2h~3h.

8. The method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... In step three, the two powders with different particle sizes are mixed and transferred into a high-strength graphite mold. The high-strength graphite mold is then placed in a vacuum hot pressing sintering furnace. A pre-pressure of 5MPa to 10MPa is applied through the pressure head and the pressure is maintained for 30 to 60 minutes. After the powder is compacted, the pressure is released and a vacuum is drawn. The flexural strength of the high-strength graphite mold is greater than 60MPa.

9. A method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... In step four, the vacuum level is expected to reach 1×10⁻⁶. -4 After applying MPa, the mold is heated at a rate of 15℃ / min to 30℃ / min until it reaches 1350℃ to 1450℃. The temperature is then held for 30 to 60 minutes. During the holding process, a pressure of 40MPa to 50MPa is continuously applied. After the holding period, heating is stopped, and the mold is cooled with the furnace. When the temperature drops to 800℃, the pressure is released. When the temperature drops below 400℃, the diffusion pump is turned off, and the mold is allowed to cool naturally to below 80℃. The high-strength graphite mold is then removed to obtain the original NiAl-based composite material blank.

10. A method for preparing a harmonized structure-reinforced NiAl-based composite material by hot deformation according to claim 1, characterized in that... The heating rate in step five is 10℃ / s to 15℃ / s; the holding time in step five is 1 min to 3 min; the rate of thermal deformation in step five is 1×10⁻⁶. -2 s -1 ~1×10 -3 s -1 The water cooling temperature mentioned in step five is 20℃~25℃.

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