A method for improving the room temperature / high temperature performance of titanium-based composite materials simultaneously

Abstract

The present application relates to a kind of preparation method for simultaneously improving the performance of titanium-based composite at room temperature / high temperature, belong to titanium-based composite preparation technical field.The method includes the following steps: preparation of polypyrrole nanotube, preparation of PNTs / Ti-based composite powder, vacuum microwave sintering, two-step rolling hot deformation;The preparation process of the present application is simple, low in cost, easy to scale preparation, in line with the core idea of "green chemistry", by microwave sintering and in-situ reaction integrated preparation of multiscale hybrid reinforced titanium-based composite, and two-step rolling deformation is realized, micron PNTs grain boundary distribution and nano TiC, TiN particles are uniformly dispersed in grain, and the prepared composite material exhibits excellent mechanical properties, compared with single scale reinforcement titanium-based composite material performance is obviously improved.The method of the present application simultaneously improves the performance of titanium-based composite at room temperature and high temperature, and provides guidance for the development of advanced high-strength and high-toughness titanium-based composite material research.

Description

Technical Field

[0001] This invention relates to a preparation method that simultaneously improves the room temperature / high temperature properties of titanium-based composite materials, belonging to the field of titanium-based composite material preparation technology. Background Technology

[0002] Titanium matrix composites (TMCs) possess advantages such as high specific strength, low density, and corrosion resistance, and are widely used in aerospace, shipbuilding, and weaponry industries. It is well known that the size and distribution of the reinforcement in TMCs significantly influence the strengthening effect. Typically, micron-scale reinforcements distributed at grain boundaries can suppress grain boundary migration in high-temperature service environments, resulting in excellent high-temperature performance. However, micron-scale reinforcements distributed at grain boundaries can induce stress concentration in the matrix, leading to defects and cracks and causing intergranular fracture, resulting in poor strength and plasticity at room temperature. Compared to micron-scale reinforcements distributed at grain boundaries, nanoscale reinforcements distributed within grains can pin and store dislocations during deformation, giving the material a good strength-plasticity balance at room temperature. However, this intragranular distribution method does not significantly improve the high-temperature performance of the material. Therefore, it is difficult to simultaneously achieve excellent high-temperature and room-temperature mechanical properties using TMCs prepared using only single-scale (micron or nanometer-scale) reinforcements.

[0003] To address the limitations of single micrometer-scale and single nanometer-scale reinforcements, researchers have incorporated both micrometer-scale and nanometer-scale reinforcements into the matrix simultaneously, hoping to leverage the advantages of both grain boundary strengthening and intragranular strengthening effects, thereby improving the room-temperature and high-temperature mechanical properties of the composite material. However, directly adding multi-scale reinforcements often introduces interfacial impurities such as oxygen or other contaminants, leading to poor interfacial bonding in the composite material. Furthermore, issues such as agglomeration defects in nanoscale reinforcements prevent effective overall performance enhancement. Compared to the additive method, in-situ synthesized ceramic reinforcements have become the preferred method for preparing high-performance TMCs due to their clean ceramic / metal interface, good interfacial bonding, high high-temperature stability, and uniform dispersion of the reinforcing phase. Therefore, researching and developing in-situ self-generated multi-scale reinforcement synergistically strengthened TMCs, enabling them to possess excellent room-temperature and high-temperature mechanical properties, is of great significance. Summary of the Invention

[0004] To address the challenge of simultaneously improving the room-temperature and high-temperature mechanical properties of TMCs, this invention provides a method for synergistic reinforcement of titanium-based composites using one-dimensional short-chain polymers (polypyrrole nanotubes, PNTs) and in-situ self-generated nano-TiC and TiN ceramic particles. In this method, PNTs serve as both a micron-sized reinforcement and a precursor for in-situ synthesis of nanoparticles. Leveraging the excellent self-dispersibility of PNTs, uniformly dispersed nano-TiC and TiN reinforcements are generated in-situ during microwave heating sintering using powder metallurgy technology, thereby preparing a multi-scale hybrid reinforced titanium-based composite material (abbreviated as: (PNTs-TiC-TiN) / Ti) of micron and nanoparticles. Subsequently, a two-step rolling hot deformation process is used to achieve the intragranular and grain boundary distribution of the multi-scale reinforcing phase (PNTs-TiC-TiN) in the titanium-based composite material, resulting in a titanium-based composite material with excellent comprehensive properties at both room-temperature and high-temperature conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing titanium-based composite materials that simultaneously improves room temperature and high temperature properties includes the following steps:

[0007] (1) Preparation of polypyrrole nanotubes

[0008] Methyl orange (C 14 H 14 N3NaO3S, MO) and anhydrous ferric chloride (FeCl3) were dissolved in deionized water, and pyrrole was added dropwise. The mixed solution was magnetically stirred, washed, filtered, and dried to prepare polypyrrole nanotubes (PNTs).

[0009] Further, the specific steps for PNTs preparation are as follows: First, MO and FeCl3 are dissolved in deionized water and ultrasonically dispersed to obtain a reddish-brown suspension. Then, pyrrole solution is added dropwise to the MO-FeCl3 suspension until the suspension turns black. The obtained suspension is heated in a magnetically stirred water bath at 20-50℃ until the solution temperature stabilizes. The solution is then kept warm and magnetically stirred for 8-36 hours. After the reaction is completed, the suspension is vacuum filtered and washed with deionized water and ethanol alternately 6-8 times until the filtrate is colorless and neutral. The obtained PNTs are dried under vacuum at 40-75℃ for 4-12 hours to obtain the prepared black powdered PNTs.

[0010] Furthermore, the molar ratio of methyl orange, ferric chloride, and pyrrole is 1:1-3:5-16, and the concentration of methyl orange in the aqueous solution is 3-15 mg / mL.

[0011] (2) Preparation of PNTs / Ti-based composite powder

[0012] PNTs were ultrasonically dispersed in an ethanol solution to obtain a PNTs suspension. Then, titanium matrix powder was added to the PNTs suspension, stirred and mixed evenly, and then vacuum dried to obtain PNTs / Ti-based composite powder.

[0013] Furthermore, the titanium-based metal powder is composed of one or more of pure titanium powder, Ti-50Nb titanium alloy powder, Ti-6Ni-4Zr-2Mo titanium alloy powder, and Ti6Al4V alloy powder. The particle size of the titanium-based metal powder is preferably 10-60μm, and the shape can be flake-shaped, spherical, or any irregular shape.

[0014] Furthermore, the PNTs mixed suspension with added Ti matrix powder was stirred electromagnetically at a stirring rate of 300-900 r / min for 10-60 min at a frequency of 20-60 kHz.

[0015] Furthermore, the drying process involves using a vacuum rotary evaporator to remove the alcohol solvent, resulting in a powder mixture; wherein the rotary evaporation flask is placed in a constant temperature water bath at 30-80℃ for 1-6 hours; the flask rotation speed is 20-200 r / min.

[0016] (3) Vacuum microwave sintering

[0017] PNTs / Ti composite powder was sintered using vacuum microwave sintering technology. The dried PNTs / Ti composite powder was molded into a cylindrical compact, and the compact was transferred into a microwave sintering furnace for sintering to obtain a solidified sintered compact.

[0018] Furthermore, the specific steps of the pressing are as follows: PNTs / Ti composite powder is loaded into a cemented carbide mold, the cemented carbide mold containing the powder mixture is placed in a hydraulic press, a pre-pressure of 380-500MPa is set, and the pressure is gradually increased to 380-500MPa at a loading condition of 50-100MPa / min, and the pressure is held for 10-60min; then the pressure is gradually reduced at an unloading condition of 100-200MPa / min to complete the pressing and molding of the powder mixture.

[0019] Further, the specific sintering steps are as follows: the pressed compact is placed in a microwave sintering furnace, the microwave power is preset to 0.1-2.0kW, the initial vacuum degree is ≤5Pa, the initial heating rate is set to 20-80℃ / min, when the temperature rises to 300-550℃, the heating rate is adjusted to 10-50℃ / min, when the temperature rises to 550-800℃, it is held for 10-50min, and then cooled with the furnace to complete the microwave sintering of the compact.

[0020] (4) Two-step rolling hot deformation

[0021] A two-step rolling hot deformation process is employed to heat deform the sintered billet. First, a low-temperature constant-speed rolling process is used to heat deform the sintered billet, followed by a high-temperature, high-speed differential-speed rolling process. This allows PNTs to be oriented along the rolling direction in the grain boundary region during the low-temperature constant-speed rolling process, while the in-situ generated TiC and TiN migrate into the grain interior as the grain boundaries move during the high-temperature, high-speed differential-speed rolling hot deformation process, achieving intragranular distribution of nanoscale reinforcements. By adjusting the hot deformation parameters, the different distribution states of micron-sized PNTs and nano-sized TiC and TiN reinforcements in the matrix are controlled, ultimately obtaining a multi-scale reinforcement (PNTs+TiC+TiN) coupled synergistically strengthened titanium matrix composite material.

[0022] Furthermore, the low-temperature constant speed rolling is performed according to the following steps: the initial rolling temperature is 300-450℃, the circumferential speed of the upper and lower rolls is controlled to be equal, and the rotation speed is 30-90mm / s; the deformation amount per pass is 3-15%, and the total deformation amount of CSR is 10-40%; the reflow temperature between passes is 300-450℃, and the reflow holding time between passes is 2-10min;

[0023] Further high-temperature, high-speed differential rolling is performed as follows: the initial rolling temperature is 850-1050℃; the differential speed ratio (high-speed roll circumferential speed (V)) is controlled. H ) / Low-speed roll circumferential speed (V L The ratio of PNTs to TiC-TiN nano-ceramic reinforcing phases is 5-20:1, the circumferential speed of the high-speed rolls is 2000-400 mm / s, the deformation per pass is 3-15%, the total deformation of HRDSR is 40-70%, the reflow temperature between passes is 850-1050℃, and the reflow holding time between passes is 2-10 min. By controlling the hot rolling process, PNTs achieve oriented arrangement of grain boundaries during deformation, while the TiC-TiN nano-ceramic reinforcing phase is uniformly distributed within the grains, ultimately preparing a multiphase (PNTs-TiC-TiN) coupled reinforced titanium-based composite material.

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

[0025] (1) The one-dimensional short molecular chain polymers (PNTs) used in this invention are simpler, lower in cost, and easier to prepare on a large scale than traditional carbon nanomaterials (carbon nanotubes, graphene), which conforms to the core idea of ​​"green chemistry". Furthermore, PNTs have unique self-dispersibility and excellent mechanical strengthening effect.

[0026] (2) This invention prepares a multi-scale hybrid reinforced titanium-based composite material by microwave sintering and in-situ reaction. In the process of vacuum microwave sintering, PNTs react with the titanium matrix in situ to generate TiC and TiN nano-ceramic reinforcements. Through two-step rolling hot deformation, the grain boundary orientation of micron-sized PNTs and the uniform intragranular distribution of nano-sized ceramic reinforcements (TiC and TiN) are achieved, which effectively controls the distribution law of multi-phase reinforcements and is conducive to the three reinforcements exerting their respective strengthening advantages.

[0027] (3) The multi-scale hybrid reinforced titanium-based composite material prepared by the present invention not only inhibits the migration of matrix grain boundaries under high temperature service conditions and endows the material with excellent high temperature performance, but also makes full use of the Orovan strengthening effect of intragranular TiC and TiN to effectively improve the storage capacity of matrix dislocations, and greatly promotes the simultaneous improvement of high temperature performance and room temperature performance of composite material.

[0028] (4) The method described in this invention is simple to operate, highly practical and universal, and can prepare high-performance titanium-based composite materials that have excellent performance at both high and low temperatures. It provides guidance for the research on developing advanced high-strength and high-toughness titanium-based composite materials. Therefore, this invention has important application value. Attached Figure Description

[0029] Figure 1 The image shows a TEM (transmission electron microscope) image of the polypyrrole nanotubes prepared in step (1) of Example 1.

[0030] Figure 2 This is a high-magnification TEM (transmission electron microscope) image of the polypyrrole nanotubes prepared in step (1) of Example 1.

[0031] Figure 3 The image shows the SEM image of the PNTs / Ti composite powder in step (3) of Example 1.

[0032] Figure 4 The image shows the surface SEM image of the PNTs-TiC-TiN / Ti composite material in step (4) of Example 1.

[0033] Figure 5 This is a low-magnification TEM image of the PNTs-TiC-TiN / Ti composite material in step (4) of Example 1.

[0034] Figure 6 This is a high-magnification TEM image of the PNTs-TiC-TiN / Ti composite material in step (4) of Example 1.

[0035] Figure 7 This is a SEM image of the surface of the PNTs-TiC-TiN / Ti composite material in Example 2.

[0036] Figure 8This is a TEM image of the PNTs-TiC-TiN / Ti composite material in Example 2. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are obtainable from publicly available commercial sources.

[0038] In the following embodiments:

[0039] Methyl orange (C 14 H 14 N3NaO3S, 95%; anhydrous ferric chloride (FeCl3, 99.9%); pyrrole (C4H5N, 99%), Shanghai Aladdin Reagent Co., Ltd.

[0040] Ti-based powder is in the form of flakes or near spherical particles, with a particle size of 10-60 μm and a purity of 98.5 wt.%, manufactured by Ganzhou Jingke Technology Co., Ltd.

[0041] Example 1

[0042] A method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials, comprising the following specific steps:

[0043] (1) Preparation of polypyrrole nanotubes

[0044] 1.1) 1M methyl orange (C 14 H 14 N3NaO3S, MO) and 1M anhydrous ferric chloride (FeCl3) were dissolved in 300mL of deionized water and ultrasonically dispersed for 30min to obtain a reddish-brown MO-FeCl3 suspension. Then, 5M pyrrole was added dropwise to the MO-FeCl3 suspension and placed in a magnetically stirred water bath and reacted at 30℃ for 10h to obtain a PNTs suspension.

[0045] 1.2) The PNTs suspension was vacuum filtered, and washed six times alternately with deionized water and ethanol until the filtrate was colorless and neutral. The resulting black PNTs powder was placed in a vacuum drying oven and dried at 50°C for 6 hours to obtain the prepared black powdered PNTs. The microstructure of the PNTs is characterized as follows: Figure 1 , Figure 2 As shown;

[0046] (2) Preparation of PNTs / Ti-based composite powder

[0047] 2.1) Weigh 3g of PNT solid powder and add it to 2000mL of ethanol solution. Disperse the PNTs by ultrasonication at 1000W for 30min to ensure uniform dispersion.

[0048] 2.2) 100g of spherical pure Ti powder was added to a uniformly dispersed PNTs suspension. The mixed suspension was electromagnetically stirred at a rate of 350r / min and a frequency of 20kHz for 10min. Then, it was dried using a vacuum rotary evaporator. The rotary evaporation flask was placed in a constant temperature water bath at 50℃ for 3h, and dried by rotary evaporation at a rotation speed of 100r / min to obtain PNTs / Ti composite powder. The microstructure of the composite powder is characterized as follows: Figure 3 As shown;

[0049] (3) Vacuum microwave sintering

[0050] 3.1) 50g of PNTs / Ti composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 400MPa. The pressure was gradually increased to 400MPa at a loading condition of 60MPa / min and held for 20min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture.

[0051] 3.2) The pressed billet is placed in a microwave sintering furnace with a preset microwave power of 0.5kW, an initial vacuum degree of ≤5Pa, and an initial heating rate of 60℃ / min. When the temperature reaches 400℃, the heating rate is adjusted to 20℃ / min. When the temperature reaches 600℃, it is held for 20min and then cooled with the furnace to obtain a solidified PNTs-TiC-TiN / Ti sintered billet.

[0052] (4) Two-step rolling hot deformation

[0053] 4.1) First, the PNTs-TiC-TiN / Ti sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 300℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 45mm / s. The deformation amount per pass is 3%, and the total deformation amount of CSR is 20%. The reflow temperature between passes is 300℃, and the reflow holding time between passes is 2min.

[0054] 4.2) Secondly, high-temperature, high-speed differential rolling is used to perform hot deformation treatment on the pre-deformed billet, with an initial rolling temperature of 850℃; the differential speed ratio (high-speed roll circumferential speed (V)) is controlled. H ) / Low-speed roll circumferential speed (V LThe ratio of PNTs to TiC / TiN was 5:1, the circumferential speed of the high-speed rolls was 600 mm / s, the deformation per pass was 5%, and the total HRDSR deformation was 60%. The reflow temperature between passes was 850℃, and the reflow holding time between passes was 5 min. By controlling the hot rolling process, PNTs achieved oriented grain boundary distribution during deformation, while the TiC-TiN nanoceramic reinforcing phase was uniformly distributed within the grains. Finally, a multiphase (PNTs-TiC-TiN) coupled reinforced titanium-based composite material was prepared. The SEM characterization of the PNTs-TiC-TiN / Ti composite material surface is shown below. Figure 4 As shown, its TEM characterization is as follows Figure 5 , Figure 6 As shown;

[0055] Depend on Figure 1 , Figure 2 It can be seen that the synthesized PNTs possess a hexagonal hollow tubular structure and straight characteristics, without obvious mutual curling and entanglement, exhibiting good self-dispersion. The PNT sidewalls show a distinct prismatic profile and localized roughness. From... Figure 1 As shown in the illustrations, PNTs contain abundant carbon and nitrogen elements. When used as reinforcing materials in composites, these unique profile configurations and abundant nitrogen doping can enhance interfacial adhesion and improve interfacial strength. Furthermore, PNTs can provide the necessary carbon and nitrogen sources for in-situ authigenic TiC and TiN.

[0056] from Figure 3 As can be seen, after stirring and mixing, the pure titanium powder and PNTs are evenly mixed, and the PNTs are evenly dispersed on the surface of the Ti powder without obvious agglomeration.

[0057] from Figure 4 As can be seen, after hot deformation, a uniform distribution of micron-sized PNTs grain boundaries is achieved. The grain boundary distribution of PNTs can connect several grains in series, which can effectively suppress the migration and rotation of grain boundaries during the hot deformation process, thus obtaining excellent high-temperature mechanical properties.

[0058] from Figure 5 , Figure 6 As can be seen, micron-sized PNTs are concentrated at grain boundaries, while nano-sized in-situ self-generated TiC and TiN ceramic reinforcing particles migrate with grain boundaries during hot deformation and separate from grain boundaries within the grains, often concentrating within the grains. This unique reinforcement distribution can simultaneously leverage the advantages of grain boundary strengthening and intragranular strengthening effects, which is beneficial for improving the room temperature-high temperature performance of titanium-based composite materials.

[0059] Example 2

[0060] A method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials, comprising the following specific steps:

[0061] (1) Preparation of polypyrrole nanotubes

[0062] 1.1) 1M methyl orange (C 14 H 14 N3NaO3S, MO) and 2M anhydrous ferric chloride (FeCl3) were dissolved in 300mL of deionized water and ultrasonically dispersed for 30min to obtain a reddish-brown MO-FeCl3 suspension. Then, 10M pyrrole was added dropwise to the MO-FeCl3 suspension and placed in a magnetically stirred water bath and reacted at 40℃ for 12h to obtain a PNTs suspension.

[0063] 1.2) The PNTs suspension was vacuum filtered and washed 8 times with deionized water and ethanol alternately until the filtrate was colorless and neutral. The obtained black PNTs powder was placed in a vacuum drying oven and dried at 75°C for 4 hours to obtain the prepared PNTs.

[0064] (2) Preparation of PNTs / Ti-based composite powder

[0065] 2.1) Weigh 3g of PNT solid powder and add it to 2000mL of ethanol solution. Disperse the PNTs by ultrasonication at 1000W for 30min to ensure uniform dispersion.

[0066] 2.2) 100g of flake-shaped pure Ti powder was added to a uniformly dispersed PNTs suspension. The mixed suspension was stirred at a speed of 500r / min and a frequency of 40KHz for 30min. Then, it was dried using a vacuum rotary evaporator. The rotary evaporation flask was placed in a constant temperature water bath at 40℃ for 6h and dried by rotary evaporation at a speed of 100r / min to obtain PNTs / Ti composite powder.

[0067] (3) Vacuum microwave sintering

[0068] 3.1) 50g of PNTs / Ti composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 500MPa. The pressure was gradually increased to 500MPa at a loading condition of 100MPa / min and held for 10min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture.

[0069] 3.2) Place the pressed billet into a microwave sintering furnace. The microwave power is preset to 2.0kW, the initial vacuum degree is ≤5Pa, and the initial heating rate is set to 80℃ / min. When the temperature reaches 550℃, the heating rate is adjusted to 50℃ / min. When the temperature reaches 800℃, it is held for 10min and then cooled with the furnace to obtain a solidified PNTs-TiC-TiN / Ti sintered billet.

[0070] (4) Hot working deformation

[0071] 4.1) First, the PNTs-TiC-TiN / Ti sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 350℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 90mm / s. The deformation amount per pass is 5%, and the total deformation amount of CSR is 30%. The reflow temperature between passes is 350℃, and the reflow holding time between passes is 5min.

[0072] 4.2) Secondly, the pre-deformed billet was hot-deformed using high-temperature, high-speed differential rolling. The initial rolling temperature was 950℃; the differential speed ratio (high-speed roll circumferential speed (VH) / low-speed roll circumferential speed (VL)) was controlled at 10:1, and the high-speed roll circumferential speed was 2000 mm / s; the deformation per pass was 15%, and the total HRDSR deformation was 50%; the reflow temperature between passes was 950℃, and the reflow holding time between passes was 10 min. By controlling the hot rolling process, PNTs achieved oriented grain boundary distribution during deformation, while the TiC-TiN nanoceramic reinforcing phase was uniformly distributed within the grains. Finally, a multiphase (PNTs-TiC-TiN) coupled reinforced titanium-based composite material was prepared. The SEM characterization of the PNTs-TiC-TiN / Ti composite material surface is as follows: Figure 7 As shown, its TEM characterization is as follows Figure 8 As shown.

[0073] from Figure 7 As can be seen, thanks to the excellent self-dispersibility of PNTs, high volume fraction PNTs can be uniformly distributed at the grain boundaries of the Ti matrix without obvious agglomeration, which is conducive to the excellent mechanical strengthening effect of PNTs.

[0074] from Figure 8 As can be seen, achieving uniform dispersion of nano-TiC and TiN particles within the grains through thermal deformation is beneficial for leveraging the orovan strengthening effect of the nano-reinforcement, effectively improving the dislocation storage capacity of the material, and enabling the composite material to obtain excellent fracture toughness and uniform elongation.

[0075] Example 3

[0076] A method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials, comprising the following specific steps:

[0077] (1) Preparation of polypyrrole nanotubes

[0078] 1.1) 1M methyl orange (C 14 H 14N3NaO3S, MO) and 1M anhydrous ferric chloride (FeCl3) were dissolved in 300 mL of deionized water and ultrasonically dispersed for 30 min to obtain a reddish-brown MO-FeCl3 suspension. Then, 11M pyrrole was added dropwise to the MO-FeCl3 suspension and the mixture was placed in a magnetically stirred water bath and heated at 50 °C for 8 h to obtain a PNTs suspension.

[0079] 1.2) The PNTs suspension was vacuum filtered and washed 6 times with deionized water and ethanol alternately until the filtrate was colorless and neutral. The obtained black PNTs powder was placed in a vacuum drying oven and dried at 60°C for 8 hours to obtain the prepared PNTs.

[0080] (2) Preparation of PNTs / Ti-based composite powder

[0081] 2.1) Weigh 3g of PNT solid powder and add it to 2000mL of ethanol solution. Disperse the PNTs evenly by ultrasonication at 1000W ultrasonic power for 50min.

[0082] 2.2) 100g of spherical Ti6Al4V alloy powder was added to a uniformly dispersed PNTs suspension. The mixed suspension was electromagnetically stirred at a rate of 900r / min and a frequency of 60KHz for 60min. Then, it was dried using a vacuum rotary evaporator. The rotary evaporation flask was placed in a constant temperature water bath at 80℃ for 3h and dried by rotary evaporation at a rotation speed of 200r / min to obtain PNTs / Ti6Al4V composite powder.

[0083] (3) Vacuum microwave sintering

[0084] 3.1) 50g of PNTs / Ti6Al4V composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 480MPa. The pressure was gradually increased to 480MPa at a loading condition of 90MPa / min and held for 30min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture.

[0085] 3.2) The pressed billet is placed in a microwave sintering furnace with a preset microwave power of 1.5kW, an initial vacuum degree of ≤5Pa, and an initial heating rate of 40℃ / min. When the temperature reaches 450℃, the heating rate is adjusted to 30℃ / min. When the temperature reaches 700℃, it is held for 30min and then cooled with the furnace to obtain a solidified PNTs-TiC-TiN / Ti6Al4V sintered billet.

[0086] (4) Two-step rolling hot deformation

[0087] 4.1) First, the PNTs-TiC-TiN / Ti6Al4V sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 400℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 55mm / s. The deformation amount per pass is 5%, and the total deformation amount of CSR is 40%. The reheating temperature between passes is 400℃, and the reheating holding time between passes is 5min.

[0088] 4.2) Secondly, high-temperature, high-speed differential rolling is used to perform hot deformation treatment on the pre-deformed billet, with an initial rolling temperature of 1000℃; the differential speed ratio (high-speed roll circumferential speed (V)) is controlled. H ) / Low-speed roll circumferential speed (V L The ratio of PNTs to TiC nano-ceramic reinforcing phases was 15:1, the circumferential speed of the high-speed rolls was 1200 mm / s, the deformation per pass was 5%, the total deformation of HRDSR was 40%, the reflow temperature between passes was 1000℃, and the reflow holding time between passes was 5 min. By controlling the hot rolling process, PNTs achieved oriented arrangement of grain boundaries during deformation, while the TiC-TiN nano-ceramic reinforcing phase was uniformly distributed within the grains, and finally, a multiphase (PNTs-TiC-TiN) coupled reinforced titanium-based composite material was prepared.

[0089] Example 4

[0090] A method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials, comprising the following specific steps:

[0091] (1) Preparation of polypyrrole nanotubes

[0092] 1.1) 1M methyl orange (C 14 H 14 N3NaO3S, MO) and 3M anhydrous ferric chloride (FeCl3) were dissolved in 300mL of deionized water and ultrasonically dispersed for 30min to obtain a reddish-brown MO-FeCl3 suspension. Then, 16M pyrrole was added dropwise to the MO-FeCl3 suspension and placed in a magnetically stirred water bath and reacted at 20℃ for 36h to obtain a PNTs suspension.

[0093] 1.2) The PNTs suspension was vacuum filtered and washed 7 times with deionized water and ethanol alternately until the filtrate was colorless and neutral. The obtained black PNTs powder was placed in a vacuum drying oven and dried at 40°C for 12 hours to obtain the prepared PNTs.

[0094] (2) Preparation of PNTs / Ti-based composite powder

[0095] 2.1) Weigh 3g of PNT solid powder and add it to 2000mL of ethanol solution. Disperse the PNTs evenly by ultrasonication at 1000W ultrasonic power for 50min.

[0096] 2.2) 100g of spherical Ti-50Nb alloy powder was added to a uniformly dispersed PNTs suspension. The mixed suspension was stirred at a rate of 300r / min for 10min. Then, it was dried by rotary evaporation at 30℃ and a rotation speed of 20r / min using a vacuum rotary evaporator to obtain PNTs / Ti-50Nb composite powder.

[0097] (3) Vacuum microwave sintering

[0098] 3.1) 50g of PNTsTi-50Nb composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 380MPa. The pressure was gradually increased to 380MPa at a loading condition of 50MPa / min and held for 60min. Then the pressure was gradually reduced at a unloading condition of 200MPa / min to complete the pressing and molding of the powder mixture.

[0099] 3.2) The pressed billet is placed in a microwave sintering furnace with a preset microwave power of 0.1kW, an initial vacuum degree of ≤5Pa, and an initial heating rate of 20℃ / min. When the temperature reaches 300℃, the heating rate is adjusted to 10℃ / min. When the temperature reaches 550℃, it is held for 50min and then cooled with the furnace to obtain a solidified PNTs-TiC-TiN / Ti-50Nb sintered billet.

[0100] (4) Two-step rolling hot deformation

[0101] 4.1) First, the PNTs-TiC-TiN / Ti-50Nb sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 450℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 30mm / s. The deformation amount per pass is 15%, and the total deformation amount of CSR is 10%. The reheating temperature between passes is 450℃, and the reheating holding time between passes is 10min.

[0102] 4.2) Secondly, high-temperature, high-speed differential rolling is used to perform hot deformation treatment on the pre-deformed billet, with an initial rolling temperature of 1050℃; the differential speed ratio (high-speed roll circumferential speed (V)) is controlled. H ) / Low-speed roll circumferential speed (V L The ratio of PNTs to TiC nano-ceramic reinforcing phases was 20:1, the circumferential speed of the high-speed rolls was 2000 mm / s, the deformation per pass was 3%, the total deformation of HRDSR was 70%, the reflow temperature between passes was 1050℃, and the reflow holding time between passes was 2 min. By controlling the hot rolling process, PNTs achieved oriented grain boundary arrangement during deformation, while the TiC-TiN nano-ceramic reinforcing phase was uniformly distributed within the grains, ultimately preparing a multiphase (PNTs-TiC-TiN) coupled reinforced titanium-based composite material.

[0103] The composite material prepared by the preparation method described in the above embodiments has a phase composition including 0.5%-10% PNTs, 0.1%-8% TiC, 0.1%-4% TiN by volume, and a Ti matrix with a balanced composition. The TiC and TiN particles are generated by the in-situ reaction of PNTs with the solid phase of the Ti matrix during microwave sintering. The PNTs have a length of 5-10 μm and a diameter of 50-200 nm. The in-situ self-generated TiC particles have a diameter of 5 nm-300 nm, and the in-situ self-generated TiN particles have a diameter of 15 nm-200 nm.

[0104] Comparative Example 1

[0105] (1) Weigh 3.0g of TiC solid powder and add it to 2000mL of ethanol solution. Disperse it ultrasonically for 30min at 1000W ultrasonic power. Add 100g of spherical pure Ti powder to the uniformly dispersed TiC suspension. Stir the mixed suspension at 350r / min for 10min. Then, use a vacuum rotary evaporator to dry it at 50℃ and a rotation speed of 100r / min to obtain TiC / Ti composite powder.

[0106] (2) 50g of TiC / Ti composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 400MPa. The pressure was gradually increased to 400MPa at a loading condition of 60MPa / min and held for 20min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture. The pressed blank was placed in a microwave sintering furnace. The microwave power was set to 0.5kW, the initial vacuum degree was ≤5Pa, and the initial heating rate was set to 60℃ / min. When the temperature reached 400℃, the heating rate was adjusted to 20℃ / min. When the temperature reached 600℃, it was held for 20min. Then it was cooled with the furnace to obtain a solidified TiC / Ti sintered blank.

[0107] (3) First, the TiC / Ti sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 300℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 45mm / s. The deformation amount per pass is 3%, and the total deformation amount of CSR is 20%. The reflow temperature between passes is 300℃, and the reflow holding time between passes is 2min. Then, the pre-deformed billet is subjected to hot deformation treatment using high-temperature high-speed differential rolling. The initial rolling temperature is 850℃. The differential speed ratio (high-speed roll circumferential speed (V)) is controlled to be 300℃. H ) / Low-speed roll circumferential speed (V LThe ratio of the high-speed rolls to the high-speed rolls was 5:1, the circumferential speed of the high-speed rolls was 600 mm / s, the deformation per pass was 5%, the total deformation of the HRDSR was 60%, the reflow temperature between passes was 850℃, and the reflow holding time between passes was 5 min. Finally, a titanium-based composite material reinforced with TiC was prepared.

[0108] Comparative Example 2

[0109] (1) Weigh 3.0g of TiN solid powder and add it to 2000mL of ethanol solution. Disperse it ultrasonically for 30min at 1000W ultrasonic power. Add 100g of spherical pure Ti powder to the uniformly dispersed TiN suspension. Stir the mixed suspension at 350r / min for 10min. Then dry it by rotary evaporation at 50℃ and 100r / min to obtain TiN / Ti composite powder.

[0110] (2) 50g of TiN / Ti composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 400MPa. The pressure was gradually increased to 400MPa at a loading condition of 60MPa / min and held for 20min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture. The pressed blank was placed in a microwave sintering furnace with a preset microwave power of 0.5kW, an initial vacuum degree of ≤5Pa, and an initial heating rate of 60℃ / min. When the temperature reached 400℃, the heating rate was adjusted to 20℃ / min. When the temperature reached 600℃, it was held for 20min. Then it was cooled with the furnace to obtain a solidified TiN / Ti sintered blank.

[0111] (3) First, the TiN / Ti sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 300℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 45mm / s. The deformation amount per pass is 3%, and the total CSR deformation amount is 20%. The reflow temperature between passes is 300℃, and the reflow holding time between passes is 2min. Then, the pre-deformed billet is subjected to hot deformation treatment using high-temperature high-speed differential rolling. The initial rolling temperature is 850℃. The differential speed ratio (high-speed roll circumferential speed (V)) is controlled to be equal. H ) / Low-speed roll circumferential speed (V L The ratio of the high-speed rolls to the high-speed rolls was 5:1, the circumferential speed of the high-speed rolls was 600 mm / s, the deformation per pass was 5%, the total deformation of the HRDSR was 60%, the reflow temperature between passes was 850℃, and the reflow holding time between passes was 5 min. Finally, a titanium-based composite material reinforced with TiN was prepared.

[0112] Comparative Example 3

[0113] (1) Weigh 1g of CNTs, 1g of TiC and 1g of TiN solid powder respectively and add them to 2000mL of ethanol solution. Disperse them ultrasonically for 30min at 1000W ultrasonic power. Add 100g of spherical pure Ti powder to the uniformly dispersed CNTs-TiC-TiN suspension. Stir the mixed suspension at 350r / min for 10min. Then dry it by rotary evaporation at 50℃ and 100r / min to obtain CNTs-TiC-TiN / Ti composite powder.

[0114] (2) 50g of CNTs-TiC-TiN / Ti composite powder was loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The cemented carbide mold containing the powder mixture was placed in a hydraulic press. The pre-pressure was set to 400MPa. The pressure was gradually increased to 400MPa at a loading condition of 60MPa / min and held for 20min. Then the pressure was gradually reduced at a unloading condition of 100MPa / min to complete the pressing and molding of the powder mixture. The pressed blank was placed in a microwave sintering furnace with a preset microwave power of 0.5kW, an initial vacuum degree of ≤5Pa, and an initial heating rate of 60℃ / min. When the temperature reached 400℃, the heating rate was adjusted to 20℃ / min. When the temperature reached 600℃, it was held for 20min. Then it was cooled with the furnace to obtain a solidified CNTs-TiC-TiN / Ti sintered blank.

[0115] (3) First, the CNTs-TiC-TiN / Ti sintered billet is subjected to hot deformation treatment using a low-temperature constant-speed rolling process. The initial rolling temperature is 300℃, and the circumferential speed of the upper and lower rolls is controlled to be equal and the rotation speed is 45mm / s. The deformation amount per pass is 3%, and the total deformation amount of CSR is 20%. The reflow temperature between passes is 300℃, and the reflow holding time between passes is 2min. Then, the pre-deformed billet is subjected to hot deformation treatment using a high-temperature high-speed differential rolling process. The initial rolling temperature is 850℃. The differential speed ratio (high-speed roll circumferential speed (V)) is controlled to be equal. H ) / Low-speed roll circumferential speed (V L The ratio of CNTs to TiC to TiN was 5:1, the circumferential speed of the high-speed rolls was 600 mm / s, the deformation per pass was 5%, the total deformation of HRDSR was 60%, the reflow temperature between passes was 850℃, and the reflow holding time between passes was 5 min. Finally, a titanium-based composite material reinforced with CNTs-TiC-TiN was prepared.

[0116] Table 1. Comparison of room temperature (25℃) and high temperature (600℃) tensile properties of titanium-based composite materials prepared in the examples and comparative examples.

[0117]

[0118]

[0119] The mechanical properties of the composite materials prepared in Examples 1-4 and Comparative Examples 1-3 were tested. The test results summarized in Table 1 show that the in-situ self-generated multi-scale coupled reinforced titanium-based composite materials achieve excellent strength-ductility matching at room temperature while maintaining excellent high-temperature mechanical properties, greatly improving the overall performance of the composite materials. The in-situ self-generated TiC and TiN reinforcements are uniformly distributed within the grains, serving as sites for dislocation multiplication and pile-up, improving the dislocation storage capacity of the composite material and alleviating stress concentration during deformation to achieve good fracture elongation. Simultaneously, the in-situ self-generated nano-TiC and TiN at the PNTs interface significantly improves the interfacial bonding strength between PNTs and the Ti matrix, effectively pinning PNTs, improving the load transfer efficiency of PNTs, and achieving excellent mechanical strengthening effects. Furthermore, the micron-sized PNTs suppress grain boundary migration and rotation during high-temperature tensile deformation, resulting in superior high-temperature mechanical properties. This demonstrates the synergistic reinforcement effect of the coupled, interactive reinforcement phases (PNTs-TiC-TiN) of different dimensions in the Ti-based composite material.

[0120] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing titanium-based composite materials that simultaneously improves room temperature and high temperature properties, characterized in that, The method steps are as follows: (1) Methyl orange (C 14 H 14 N3NaO3S, MO) and anhydrous ferric chloride (FeCl3) were dissolved in deionized water, and pyrrole was added dropwise. The mixed solution was magnetically stirred, washed, filtered, and dried to prepare polypyrrole nanotubes (PNTs). (2) PNTs were ultrasonically dispersed in an ethanol solution to obtain a PNTs suspension. Then, titanium matrix powder was added to the PNTs suspension, stirred and mixed evenly, and then dried to obtain PNTs / Ti-based composite powder. (3) The PNTs / Ti composite powder was sintered using vacuum microwave sintering technology. The dried PNTs / Ti composite powder was molded into a cylindrical compact and then transferred into a microwave sintering furnace to obtain a solidified sintered compact. (4) A two-step rolling hot deformation process is used to perform hot deformation treatment on the sintered billet. First, the sintered billet is hot deformed using a low-temperature constant speed rolling (CSR) process, and then the pre-deformed billet is hot deformed using a high-temperature high-speed differential speed rolling (HRDSR) process. By controlling the process conditions of hot deformation, PNTs are regularly oriented at the grain boundaries during the process, while the TiC-TiN nano-ceramic reinforcing phase is uniformly distributed within the grains. Finally, a multi-scale reinforced PNTs+TiC+TiN coupled synergistic strengthening titanium matrix composite material is obtained.

2. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The specific steps for preparing polypyrrole nanotubes in step (1) are as follows: MO and FeCl3 were dissolved in deionized water and ultrasonically dispersed to obtain a reddish-brown suspension. Pyrrole solution was then added dropwise to the MO-FeCl3 suspension until the suspension turned black. The resulting suspension was heated in a magnetically stirred water bath at 20-50℃ until the solution temperature stabilized, and then kept at this temperature and magnetically stirred for 8-36 h. After the reaction was completed, the suspension was vacuum filtered and washed 6-8 times alternately with deionized water and ethanol until the filtrate was colorless and neutral. The obtained PNTs were dried under vacuum at 40-75℃ for 4-12 h to obtain the prepared black powdered PNTs.

3. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The titanium matrix powder in step (2) is composed of one or more of pure titanium powder, Ti-50Nb titanium alloy powder, Ti-6Ni-4Zr-2Mo titanium alloy powder, and Ti6Al4V alloy powder, and the particle size of the titanium matrix powder is 10-60 μm.

4. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The stirring in step (2) is carried out by electromagnetic stirring at a stirring rate of 300-900 r / min for 10-60 min and a frequency of 20-60 KHz.

5. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The drying in step (2) is carried out using a vacuum rotary evaporator to remove the alcohol solvent and obtain a powder mixture. The rotary evaporator flask is placed in a constant temperature water bath at 30-80℃ for 1-6 hours, and the flask rotation speed is 20-200 r / min.

6. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The specific steps of pressing the compact in step (3) are as follows: PNTs / Ti composite powder is loaded into a cemented carbide mold, the cemented carbide mold containing the powder mixture is placed in a hydraulic press, the pre-pressure is set to 380-500 MPa, the pressure is gradually increased to 380-500 MPa at 50-100 MPa / min, and the pressure is held for 10-60 min; then the pressure is gradually reduced at 100-200 MPa / min to complete the pressing and forming of the powder mixture.

7. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The specific steps of sintering in step (3) are as follows: the pressed blank is placed in a microwave sintering furnace, the microwave power is preset to 0.1-2.0 kW, the initial vacuum degree is ≤5 Pa, the initial heating rate is set to 20-80℃ / min, when the temperature rises to 300-550℃, the heating rate is adjusted to 10-50℃ / min, when the temperature rises to 550-800℃, it is held for 10-50 min, and then cooled with the furnace to complete the microwave sintering of the pressed blank.

8. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: In step (4), the low-temperature constant speed rolling is performed as follows: the initial rolling temperature is 300-450℃, the circumferential speed of the upper and lower rolls is controlled to be equal, and the rotation speed is 30-90 mm / s; the deformation amount per pass is 3-15%, and the total deformation amount of CSR is 10-40%; the reheating temperature between passes is 300-450℃, and the reheating holding time between passes is 2-10 min.

9. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: The high-temperature, high-speed differential rolling in step (4) is performed as follows: the initial rolling temperature is 850-1050℃; the circumferential speed V of the high-speed rolls is controlled. H Low-speed roll circumferential speed V L The ratio of PNTs to TiC-TiN nanoceramic reinforcing phases is 5-20:1, the circumferential speed of the high-speed rolls is 2000-400 mm / s, the deformation per pass is 3-15%, the total HRDSR deformation is 40-70%, the reflow temperature between passes is 850-1050℃, and the reflow holding time between passes is 2-10 min. By controlling the process conditions of the hot rolling process, PNTs are regularly oriented at the grain boundaries during the process, while the TiC-TiN nanoceramic reinforcing phase is uniformly distributed within the grains, and finally, a multiphase PNTs-TiC-TiN coupled reinforced titanium-based composite material is prepared.

10. The preparation method for simultaneously improving the room temperature / high temperature properties of titanium-based composite materials according to claim 1, characterized in that: In step (1), the molar ratio of methyl orange, anhydrous ferric chloride, and pyrrole is 1:1-3:5-16, and the concentration of methyl orange in the aqueous solution is 3-15 mg / mL.

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