Method for preparing high-toughness TiC-Ti2Cu / titanium-based composite material based on titanium thermal reaction

Abstract

The invention relates to a method for preparing a high-toughness TiC-Ti2Cu / titanium-based composite material based on a titanium thermal reaction, and belongs to the technical field of titanium-based composite material preparation. The method comprises the following steps: firstly, preparing a reinforcement precursor PNSs (at) Cu2O by adopting a molecular-level blending method, and then carrying out pre-pressing molding on mixed powder of the PNSs (at) Cu2O and titanium-based metal powder to obtain a pressed blank; the preparation method comprises the following steps: pressing a titanium-based metal powder into a compact, then sintering the compact, and enabling a reinforcement precursor to generate a TiC and Ti2Cu two-phase reinforcement which is dispersedly distributed in a crystal on the titanium-based metal powder in situ, so as to obtain a TiC-Ti2Cu / titanium-based composite material block, thereby realizing the successful development of the high-performance titanium-based composite material. The method is easy to operate, low in cost and high in practicability, large-scale production can be achieved, the high-strength and high-toughness titanium-based composite material can be prepared, and guidance is provided for research on development of advanced high-strength and high-toughness titanium-based composite materials.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing a high-strength and high-toughness TiC-Ti2Cu / titanium-based composite material based on a titanium thermal reaction, and belongs to the technical field of titanium-based composite material preparation. BACKGROUND

[0002] Titanium matrix composites (TMCs) have been widely used in aerospace, space technology and weapon equipment fields due to their high specific strength, low density, friction resistance and corrosion resistance. The selection of the reinforcing phase is a core link in the design and preparation of titanium matrix composites, and directly determines the final performance, processing feasibility and application potential of the composite material. TiC is one of the most ideal reinforcing materials for titanium matrix composites due to its high elastic modulus (~420-460 GPa) and excellent thermal stability, as well as its similar thermal expansion coefficient (CTE) to Ti, thereby having good interface compatibility. At present, the in-situ synthesis method of powder metallurgy is one of the most optimal methods for preparing high-strength and high-toughness titanium matrix composites by generating TiC reinforcing phase in the Ti matrix, which can realize uniform distribution, high-purity interface and strong bonding force, and significantly improve the mechanical properties and stability of TMCs.

[0003] Polyazoles balls (PNSs) are a kind of conductive polymer, which has been widely used in energy storage, sensors, biomedical, conductive coating and other fields due to its excellent electrical conductivity, environmental stability, adjustable physical and chemical properties, and it is also an ideal precursor that can generate nanoscale TiC by in-situ reaction with Ti. The synthesis of PNSs is simple, the cost is low, and it is easy to scale up. The reinforcing effect of PNSs is excellent, and a composite material with good interface bonding and excellent strength-plasticity matching can be obtained. However, PNSs and titanium powder have great differences in size and density, so it is difficult to achieve uniform dispersion in the dispersion process. In addition, similar to carbon elemental materials, the temperature for PNSs to fully react and generate TiC in-situ is high (>1200℃), and a very high sintering temperature is often required in the sintering process, which inevitably causes grain coarsening and growth. Therefore, it is often necessary to combine rolling deformation for grain refinement. Therefore, the long process flow will increase the time cost and labor cost. It is particularly important to develop a simple and convenient technical route to solve the above problems. SUMMARY

[0004] In order to solve the problems of how to realize the uniform dispersion of PNSs and simplify the material preparation process, the application provides a method for coating PNSs with cuprous oxide (Cu2O) through a molecular-level blending method. In the method, because the size and density of Cu2O are more close to Ti, the composite precursor PNSs@Cu2O is more easily dispersed uniformly in the titanium powder in the dispersion process due to the size effect and density difference. Moreover, Cu2O can react with Ti at high temperature to generate a large amount of heat, so that the reaction temperature is lower and the reaction speed is faster, so as to realize the purpose of simplifying the process flow and uniformly dispersing PNSs. In addition, PNSs@Cu2O can react with Ti in two in-situ reactions in the sintering process, so as to generate intracrystalline dispersed TiC and Ti2Cu, thereby more effectively capturing and storing dislocations in plastic deformation, greatly improving the work hardening capacity of the material; the oxygen in Cu2O can also be solid-solved in Ti to play a synergistic strengthening role, so as to finally realize the preparation of high-strength and high-toughness titanium-based composite materials. In order to achieve the above purpose, the application provides the following technical scheme: A method for preparing high-strength and high-toughness TiC-Ti2Cu / titanium-based composite materials based on titanium thermal reaction, comprising the following steps: (1) Preparation of polypyrrole ball PNSs Anhydrous ferric chloride (FeCl3) is dissolved in deionized water, and pyrrole is added dropwise, and the mixed solution is subjected to magnetic stirring, washing, filtration and drying to prepare polypyrrole balls (PNSs); Further, the specific steps for preparing the polypyrrole ball PNSs are as follows: FeCl3 is dissolved in deionized water and uniformly dispersed by ultrasonic to obtain a brown-yellow solution, then pyrrole solution is added dropwise into the FeCl3 suspension until the suspension is black, the obtained suspension is heated in a magnetic stirring water bath at 25-60 DEG C until the solution temperature is stable, then the suspension is heated and magnetically stirred for 8-36 h, after the reaction is completed, the suspension is vacuum filtered, and deionized water and ethanol are used to wash alternately for 6-8 times until the filtrate is colorless and neutral, and the obtained PNSs are dried at 40-75 DEG C under vacuum for 4-12 h to obtain the prepared black powder PNSs; (2) Preparation of PNSs@Cu2O The PNSs powder is dispersed in a copper acetate (Cu(CH3COO)2·H2O) solution, then sodium hydroxide solution is added dropwise, and then glucose (CH2OH (CHOH)4CHO) solution is added dropwise, and the mixed solution is subjected to magnetic stirring, heating, washing, suction filtration and drying to prepare PNSs@Cu2O powder; Further, Cu(CH3COO)2·H2O, NaOH, CH2OH (CHOH)4CHO were dissolved in deionized water respectively and ultrasonic dispersed uniformly to obtain a blue suspension and two transparent solutions, PNSs was dispersed in the (Cu(CH3COO)2·H2O) suspension and NaOH solution was added drop by drop until a large amount of deep blue precipitate was produced in the suspension, then glucose (CH2OH (CHOH)4CHO) solution was added drop by drop, finally the obtained suspension was heated and stirred in a 70-80℃ magnetic stirring water bath until the suspension was completely changed into brick red, then the suspension was kept and stirred magnetically for 30 min, after the reaction was completed, the suspension was washed with deionized water until the filtrate was colorless and neutral, the suspension was vacuum filtered, and the obtained PNSs@Cu2O was dried at 60-70℃ under vacuum for 4-6 h to obtain the prepared brick red powder PNSs@Cu2O.

[0005] Further, the molar ratio of ferric chloride to pyrrole is 1-3:5-16, and the concentration of ferric chloride in the aqueous solution is 3-15 mg / mL; the molar ratio of copper acetate, sodium hydroxide and glucose is 3:5:3, and the concentration of copper acetate in the aqueous solution is 3-15 mg / mL.

[0006] (3) Preparation of PNSs@Cu2O / Ti-based composite powder PNSs@Cu2O was ultrasonic dispersed in ethanol solution to obtain PNSs@Cu2O suspension, then titanium-based powder was added to the PNSs@Cu2O suspension, stirred and mixed uniformly, vacuum dried after ball milling for a period of time to obtain PNSs@Cu2O / Ti-based composite powder; Further, the titanium-based metal powder includes one or more of pure titanium powder, Ti6Al4V alloy powder, and the particle size of the titanium-based metal powder is preferably 15-53 μm, and the shape can be flaky, spherical or any irregular shape; the added mass percentage of PNSs@Cu2O is 2%~3.5%.

[0007] Further, the PNSs@Cu2O mixed suspension with Ti-based powder is stirred at a stirring rate of 400-800 r / min for 15-45 min, and the frequency is 30-60 KHz; the ball milling ball to material ratio is 10:1~15:1; the ball milling time is 120 min~180 min; and the ball milling speed is 200 r / min~250 r / min.

[0008] Further, the drying process is carried out by using a vacuum rotary evaporator to remove the alcohol solvent to obtain a powder mixture; wherein the rotary evaporation flask is placed in a constant temperature water bath at a temperature of 30-80℃ for 1-6 h; the rotation speed of the flask is 20-200 r / min.

[0009] (4) Preparation of TiC-Ti2Cu / Ti-based composite block The PNSs@Cu2O / Ti-based composite powder is molded into a cylindrical compact, and the compact is moved into a vacuum rapid hot-pressing sintering furnace for sintering to obtain a consolidated TiC-Ti2Cu / Ti-based sintered compact.

[0010] Further, the compacting of the powder mixture is specifically as follows: the PNSs@Cu2O / Ti composite powder is loaded into a graphite mold, the graphite mold loaded with the powder mixture is placed into a hydraulic press, a pre-pressing force of 30-50 MPa is set, and the powder mixture is gradually pressed to 30-50 MPa at a loading condition of 5-10 MPa / min, and pressure maintaining is performed for 10-30 min; then the powder mixture is gradually decompressed at a decompressing condition of 10-20 MPa / min to complete the compacting of the powder mixture.

[0011] Further, the sintering is specifically as follows: the compacted compact is placed into a vacuum rapid hot-pressing sintering furnace, a pre-pressing force of 1.5 t is set, an initial vacuum degree is ≤5 Pa, an initial temperature rising rate is set to 80-100 ℃ / min, temperature rising is performed to 850-1000 ℃, and temperature maintaining is performed for 5-15 min, and then the compact is cooled with the furnace to complete the vacuum rapid hot-pressing sintering of the compact, and a titanium-based composite material with two kinds of reinforcing phases (TiC+Ti2Cu) is obtained.

[0012] Compared with the prior art, the present application has the following beneficial effects: (1) The present application coats cuprous oxide (Cu2O) on PNSs by a molecular-level blending method to obtain a composite precursor PNSs@Cu2O, and the addition of Cu2O balances the size difference and density difference between PNSs and Ti powder, so that PNSs can be more easily and uniformly dispersed in the Ti matrix powder.

[0013] (2) The present application performs a “titanium thermal reaction” between Cu2O and titanium in a solid-phase sintering reaction process, and compared with a traditional sintering reaction, the reaction speed is faster, the sintering time is shorter, and the sintering temperature is lower, and finally the process flow is simplified.

[0014] (3) The present application uses two kinds of reinforcing phases, TiC and Ti2Cu, which are generated in situ, as reinforcing bodies, and the two kinds of reinforcing phases can form good thermodynamic compatibility in the material matrix, and effectively reduce interface defects. TiC, as a hard ceramic particle, forms a second-phase reinforcement by being dispersedly distributed in the titanium matrix, effectively hinders dislocation movement, and thus improves the tensile strength and work hardening capacity of the material; Ti2Cu is an intermetallic compound precipitated phase, which can reduce interface defects and refine grains, and significantly improve the yield strength through solid solution strengthening and precipitation strengthening. TiC and Ti2Cu can simultaneously play the synergistic effect of particle reinforcement and precipitation strengthening, and simultaneously enhance the strength and plasticity of the material.

[0015] (4) The method has the advantages of simple operation, low cost, strong practicability, scalable production, and preparation of high-strength and high-toughness titanium-based composite materials, and provides guidance for the research and development of advanced high-strength and high-toughness titanium-based composite materials, and therefore, the method has important application value. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 SEM image of PNSs@Cu2O prepared in step (2) of Example 1.

[0017] Figure 2 SEM image of PNSs@Cu2O prepared in step (2) of Example 1. Figure 3 SEM image of PNSs@Cu2O prepared in step (2) of Example 1. Figure 4 SEM image of PNSs@Cu2O prepared in step (2) of Example 1.

[0018] Figure 5 SEM image of PNSs@Cu2O prepared in step (2) of Example 1. Figure 1 .

[0019] Figure 6 SEM image of PNSs@Cu2O prepared in step (2) of Example 1. Figure 2 Figure 7 Tensile property diagram of the composite material prepared in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0020] The application will be further described below in conjunction with the drawings and specific embodiments, wherein the methods are all conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0021] In the following examples: Anhydrous ferric chloride (FeCl3, 99.9%); pyrrole (C4H5N, 99%); copper acetate ((Cu(CH3COO)2·H2O), 95%); sodium hydroxide (NaOH, 99.9%), glucose (CH2OH (CHOH)4CHO, 99.9%), Shanghai Aladdin Reagent Co., Ltd.; Ti and Ti6Al4V matrix powder are flaky or near-spherical, with a particle size of 15-53 μm and a purity of 98.5 wt.%, Ganzhou Jingke Technology Co., Ltd.; Embodiment 1: A method for preparing high-toughness TiC-Ti2Cu / titanium-based composite material based on titanium thermal reaction, the specific steps are as follows: (1) Preparation of polypyrrole ball PNSs Dissolve 1 M anhydrous ferric chloride (FeCl3) in 300 mL deionized water, ultrasonic dispersion for 30 min to obtain a FeCl3 brown yellow solution, then drop 5 M pyrrole into the FeCl3 solution drop by drop, and place it in a magnetic stirring water bath under 30℃ water bath heating for 10 h to obtain a PNSs suspension; then vacuum filter the PNSs suspension, and wash it with deionized water and ethanol alternately for 6 times until the filtrate is colorless and neutral, and then place the obtained PNSs black powder in a vacuum drying box and dry it at 50℃ for 6 h to obtain the prepared black powder PNSs.

[0022] (2) Preparation of PNSs@Cu2O 2.1) Dissolve 15.6 g of copper acetate Cu(CH3COO)2·H2O, 7 g of sodium hydroxide (NaOH) and 14.1 g of glucose (CH2OH (CHOH)4CHO, 99.9%) in 500 mL, 30 mL and 100 mL deionized water respectively, ultrasonic dispersion for 10 min to obtain a blue suspension and two transparent solutions, then disperse PNSs in the copper acetate (Cu(CH3COO)2·H2O) solution, drop the sodium hydroxide (NaOH) solution into the copper acetate, then drop the glucose (CH2OH (CHOH)4CHO) solution into it, and place it in a magnetic stirring water bath under 80℃ water bath heating for 30 min to obtain a PNSs@Cu2O suspension; 2.2) Wash with deionized water until the filtrate is colorless and neutral, vacuum filter the PNSs@Cu2O suspension, and place the obtained PNSs@Cu2O brick red powder in a vacuum drying box and dry it at 60℃ for 6 h to obtain the prepared brick red powder PNSs@Cu2O, the micro-morphology of PNSs@Cu2O is shown in Figure 1 .

[0023] (3) Preparation of PNSs@Cu2O / Ti composite powder 3.1) Weigh 3 g of PNSs@Cu2O solid powder and add it to 200 mL of ethanol solution, ultrasonic dispersion for 30 min under 1000 W ultrasonic power to make PNSs@Cu2O uniformly dispersed; 3.2) 97 g of spherical pure Ti powder was added into the uniformly dispersed PNSs@Cu20 suspension, and magnetic stirring was used at a stirring rate of 400 r / min for 15 min at a frequency of 30 KHz. Then the mixed suspension was ball milled at a rate of 225 r / min for 2.5 h, and then dried by a vacuum rotary evaporator. The rotary evaporator flask was placed in a constant temperature water bath at 50°C for 3 h, and dried at a rotation speed of 100 r / min. The PNSs@Cu20 / Ti composite powder was obtained, and the micro-morphology of the composite powder was characterized as shown in Figure 3 ; (4) Preparation of TiC-Ti2Cu / Ti composite bulk 4.1) 50 g of PNSs@Cu20 / Ti composite powder was loaded into a Φ30 mm cylindrical carbide mold. The carbide mold loaded with the powder mixture was placed in a hydraulic machine, and the pre-pressing force was set to 50 MPa. The powder mixture was gradually pressed to 50 MPa at a loading condition of 5 MPa / min, and the pressure was maintained for 10 min. Then the pressure was gradually reduced at a unloading condition of 10 MPa / min to complete the pressing of the powder mixture. 4.2) The pressed compact was placed in a vacuum rapid hot-pressing sintering furnace, the pre-pressing force was set to 1.5 t, the initial vacuum degree was 5 Pa, the initial heating rate was set to 100°C / min, the temperature was raised to 850°C and maintained for 5 min, and then the furnace was cooled to complete the vacuum rapid hot-pressing sintering of the compact. The SEM characterization of the surface of the TiC-Ti2Cu / Ti composite material is shown in Figure 3 , and the TEM characterization is shown in Figure 4 ; Comparative Example 1 (1) Preparation of PNSs 1.1) 1 M anhydrous ferric chloride (FeCl3) was dissolved in 300 mL of deionized water, and ultrasonic dispersion was performed for 30 min to obtain a FeCl3 brown-yellow solution. Then 5 M pyrrole was added dropwise into the FeCl3 solution, and placed in a magnetic stirring water bath at 30°C for reaction under water bath heating for 10 h to obtain a PNSs suspension. Then the PNSs suspension was vacuum filtered, and washed with deionized water and ethanol alternately for 6 times until the filtrate was colorless and neutral. The obtained PNSs black powder was placed in a vacuum drying oven and dried at 50°C for 6 h to obtain the prepared PNSs black powder.

[0024] (2) Preparation of PNSs / Ti composite powder 2.1) 3 g of PNSs solid powder was added into 200 mL of ethanol solution, and ultrasonic dispersion was performed at a ultrasonic power of 1000 W for 30 min to uniformly disperse the PNSs; 2.2) 97 g of spherical pure Ti powder was added into the uniformly dispersed PNSs suspension, and magnetic stirring was used at a stirring rate of 400 r / min for 15 min at a frequency of 30 KHz. Then the mixed suspension was ball milled at a rate of 225 r / min for 2.5 h, and then dried by using a vacuum rotary evaporator, with the rotary evaporator flask being placed in a constant temperature water bath at a temperature of 50°C for 3 h, and dried at a rotation speed of 100 r / min, to obtain PNSs@Cu2O / Ti composite powder. The micro-morphology characterization of the composite powder is shown in FIG. 2.2; Figure 2 (3) Preparation of TiC / Ti composite bulk 3.1) 50 g of PNSs / Ti composite powder was loaded into a Φ30 mm cylindrical cemented carbide mold, and the cemented carbide mold loaded with the powder mixture was placed in a hydraulic machine, and the pre-pressing force was set to 50 MPa, and the loading condition was 5 MPa / min, and the pressure was gradually increased to 50 MPa, and the pressure was maintained for 10 min; then the unloading condition was 10 MPa / min, and the powder mixture was gradually decompressed to complete the compression molding of the powder mixture; 3.2) The pressed compact was placed in a vacuum rapid hot-pressing sintering furnace, the pre-pressing force was set to 1.5 t, the initial vacuum degree was 5 Pa, the initial heating rate was set to 100°C / min, the temperature was increased to 850°C, and the temperature was maintained for 5 min, and then the furnace was cooled, and the vacuum rapid hot-pressing sintering of the compact was completed.

[0025] From Figure 1 it can be seen that the synthesized PNSs@Cu2O prepared by molecular-level blending has a unique morphological feature, which is that the nanoscale PNSs are embedded in the micrometer-scale Cu2O. This special structure balances the size difference and density difference between PNSs and Ti matrix powder, so that better dispersion effect is obtained in the subsequent ball milling process.

[0026] From Figure 2 it can be seen that the PNSs / Ti composite powder after ball milling shows obvious agglomeration phenomenon. From Figure 3 it can be seen that the Ti powder and PNSs@Cu2O are uniformly mixed, and the PNSs@Cu2O is uniformly dispersed on the surface of the Ti powder, and no obvious agglomeration occurs. The PNSs@Cu2O / Ti composite powder shows better dispersion effect than the PNSs / Ti composite powder.

[0027] From Figure 4 ​As can be seen from the figures, due to the thermal reaction of titanium, a short-time sintering of PNSs@Cu2O / Ti can obtain nanoscale in-situ TiC and Ti2Cu reinforced particles, and the TiC provides extremely high hardness, rigidity, thermal stability and wear resistance, and is the main load transfer phase; and the Ti2Cu provides significant precipitation strengthening effect, and the coexistence of Ti2Cu and TiC can realize multi-mechanism synergistic strengthening.

[0028] From Figure 5 and Figure 6 As can be seen, most of the in-situ generated TiC and Ti2Cu are uniformly dispersed in the grain interior without obvious agglomeration. The TiC and Ti2Cu phases are closely combined with the Ti matrix without gaps or defects, and the clean and well-bonded interface between the reinforced phase and the Ti matrix helps to improve the tensile strength and the mechanical properties of the composite material. And due to the characteristics of the intracrystalline distribution of the two reinforced phases, the dislocation slip can be effectively hindered during plastic deformation. When the dislocation moves, it is forced to bypass the TiC particles (Orowan bypass mechanism), forming dislocation loops. This process increases the resistance of subsequent dislocation movement, resulting in a significant increase in dislocation density, directly improving the strength of the material; at the same time, due to the interaction between the reinforcing body and the dislocation, more dislocations are effectively captured and stored, greatly improving the work hardening capacity of the composite material, and thus obtaining excellent plasticity. Finally, a high-strength and high-toughness TiC-Ti2Cu / Ti composite material is obtained.

[0029] The tensile properties of the materials prepared in Example 1 and Comparative Example 1 were tested, and the results are shown in Figure 7 The ultimate tensile strength (UTS) of the TiC-Ti2Cu / Ti composite material is 1070 MPa, and the elongation (EL) is 13.1%. Compared with the TiC / Ti composite material under the same preparation process, the UTS is increased by 15.6%, and the EL is increased by 138%, and the performance is obviously improved. The size difference and density difference between PNSs and Ti powder are balanced by Cu2O, effectively solving the dispersion problem, thereby greatly improving the elongation; at the same time, Ti2Cu and TiC can simultaneously play the synergistic effect of particle reinforcement and precipitation strengthening, and the strength of the material is simultaneously enhanced.

[0030] Example 2: On the basis of Example 1, only the Ti metal powder in step (3) is replaced by Ti6Al4V alloy powder, and other steps and process conditions are the same as those in Example 1, and a high-strength and high-toughness TiC-Ti2Cu / Ti6Al4V composite material is obtained accordingly.

[0031] Example 3: Based on Example 1, the mass of PNSs@Cu2O solid powder was changed from 3 g to 2.5 g and the mass of Ti matrix powder was changed from 97 g to 97.5 g. Other steps and process conditions were the same as in Example 1, and a high-strength and high-toughness TiC-Ti2Cu / Ti composite material was obtained accordingly.

[0032] Comparative Example 2: Based on Example 1, pure Ti-based metal blocks were prepared using the same ball milling and sintering processes.

[0033] Comparative Example 3: Based on Example 1, pure Ti6Al4V matrix metal blocks were prepared using the same ball milling and sintering processes.

[0034] Example 4: A method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction, the specific steps of which are as follows: (1) Preparation of polypyrrole spheres (PNSs) 1 M anhydrous ferric chloride (FeCl3) was dissolved in 300 mL of deionized water and ultrasonically dispersed for 30 min to obtain a brownish-yellow FeCl3 solution. Then, 5 M pyrrole was added dropwise to the FeCl3 solution and the mixture was placed in a magnetically stirred water bath and heated at 25 °C for 36 h to obtain a PNSs suspension. The PNSs suspension was then vacuum filtered and washed 7 times alternately with deionized water and ethanol until the filtrate was colorless and neutral. The obtained black PNSs powder was placed in a vacuum drying oven and dried at 40 °C for 12 h to obtain the prepared black powdered PNSs.

[0035] (2) Preparation of PNSs@Cu2O 2.1) 15.6 g copper acetate Cu(CH3COO)2·H2O), 7 g sodium hydroxide (NaOH) and 14.1 g glucose (CH2OH (CHOH)4CHO, 99.9%) were dissolved in 500 mL, 30 mL and 100 mL of deionized water, respectively. The solutions were ultrasonically dispersed for 10 min to obtain a blue suspension and two transparent solutions. Then, PNSs were dispersed in copper acetate (Cu(CH3COO)2·H2O) solution. Sodium hydroxide (NaOH) solution was added dropwise to copper acetate, followed by glucose (CH2OH (CHOH)4CHO) solution. The mixture was placed in a magnetically stirred water bath and heated at 70 °C for 30 min to obtain PNSs@Cu2O suspension. 2.2) The PNSs@Cu2O suspension was washed with deionized water until the filtrate was colorless and neutral, and then vacuum filtered. The obtained brick red PNSs@Cu2O powder was placed in a vacuum drying oven and dried at 65 ℃ for 4 h to obtain the prepared brick red PNSs@Cu2O powder. The micro-morphology of the PNSs@Cu2O is shown in FIG. 1. Figure 1

[0036] (3) Preparation of PNSs@Cu2O / Ti composite powder 3.1) 3 g of PNSs@Cu2O solid powder was added to 200 mL of ethanol solution, and ultrasonic dispersion was performed at 1000 W ultrasonic power for 30 min to uniformly disperse the PNSs@Cu2O; 3.2) 97 g of spherical pure Ti powder was added to the uniformly dispersed PNSs@Cu2O suspension, and magnetic stirring was performed at a stirring rate of 600 r / min for 30 min at a frequency of 45 KHz. Then, the mixed suspension was ball milled at a speed of 200 r / min for 2 h, and then dried by using a vacuum rotary evaporator. The rotary evaporator flask was placed in a constant temperature water bath at a temperature of 30 ℃ for 1 h, and dried at a rotation speed of 20 r / min to obtain PNSs@Cu2O / Ti composite powder; (4) Preparation of TiC-Ti2Cu / Ti composite block 4.1) 50 g of PNSs@Cu2O / Ti composite powder was loaded into a Φ30 mm cylindrical cemented carbide mold, and the cemented carbide mold loaded with the powder mixture was placed in a hydraulic machine. The pre-pressing pressure was set to 30 MPa, and the powder mixture was gradually pressed to 30 MPa at a loading condition of 10 MPa / min, and then gradually reduced in pressure at a unloading condition of 20 MPa / min to complete the pressing of the powder mixture; 4.2) The pressed compact was placed in a vacuum rapid hot-pressing sintering furnace, the pre-pressing pressure was set to 1.5 t, the initial vacuum degree was set to 5 Pa, the initial heating rate was set to 80 ℃ / min, and the temperature was maintained at 900 ℃ for 10 min after the temperature was increased to 900 ℃, and then cooled with the furnace to complete the vacuum rapid hot-pressing sintering of the compact, thereby obtaining a TiC-Ti2Cu / Ti composite material.

[0037] Example 5: A method for preparing a high-strength and high-toughness TiC-Ti2Cu / titanium-based composite material based on titanium thermal reaction, the specific steps are as follows: (1) Preparation of polypyrrole ball PNSs ​A 1 M anhydrous ferric chloride (FeCl3) solution was prepared by dissolving FeCl3 in 300 mL of deionized water and ultrasonically dispersing for 30 min to obtain a brownish yellow FeCl3 solution. Then, 5 M pyrrole was added dropwise to the FeCl3 solution, and the mixture was placed in a magnetic stirring water bath and heated at 60°C for 8 h to obtain a PNSs suspension. The PNSs suspension was then vacuum filtered and washed with deionized water and ethanol alternately for 8 times until the filtrate was colorless and neutral. The obtained black PNSs powder was dried in a vacuum drying oven at 75°C for 4 h to obtain the prepared black PNSs powder.

[0038] (2) Preparation of PNSs@Cu2O 2.1) 15.6 g of copper acetate Cu(CH3COO)2·H2O, 7 g of sodium hydroxide (NaOH), and 14.1 g of glucose (CH2OH (CHOH)4CHO, 99.9%) were dissolved in 500 mL, 30 mL, and 100 mL of deionized water, respectively, and ultrasonically dispersed for 10 min to obtain a blue suspension and two transparent solutions. Then, the PNSs were dispersed in the copper acetate (Cu(CH3COO)2·H2O) solution, the sodium hydroxide (NaOH) solution was added dropwise to the copper acetate, and the glucose (CH2OH (CHOH)4CHO) solution was added dropwise. The mixture was placed in a magnetic stirring water bath and heated at 75°C for 30 min to obtain a PNSs@Cu2O suspension. 2.2) The PNSs@Cu2O suspension was vacuum filtered and washed with deionized water until the filtrate was colorless and neutral. The obtained PNSs@Cu2O brick red powder was dried in a vacuum drying oven at 70°C for 5 h to obtain the prepared brick red PNSs@Cu2O powder. The micro-morphology of the PNSs@Cu2O is shown in FIG. 2. Figure 1

[0039] (3) Preparation of PNSs@Cu2O / Ti composite powder 3.1) 3 g of PNSs@Cu2O solid powder was added to 200 mL of ethanol solution, and ultrasonically dispersed at a power of 1000 W for 30 min to uniformly disperse the PNSs@Cu2O. 3.2) 97 g of spherical pure Ti powder was added to the uniformly dispersed PNSs@Cu2O suspension, and stirred at a stirring rate of 800 r / min for 45 min and a frequency of 60 KHz. Then, the mixed suspension was ball-milled at a rate of 250 r / min for 3 h, and dried using a vacuum rotary evaporator. The rotary evaporator flask was placed in a constant temperature water bath at a temperature of 80°C for 6 h, and dried at a rotation speed of 200 r / min to obtain the PNSs@Cu2O / Ti composite powder. ​(4) Preparation of TiC-Ti2Cu / Ti composite block 4.1) 50 g of PNSs@Cu2O / Ti composite powder was loaded into a Φ30 mm cylindrical cemented carbide mold, and the cemented carbide mold loaded with the powder mixture was placed in a hydraulic machine, a pre-pressing force of 40 MPa was set, and the loading was gradually increased to 40 MPa at a loading rate of 7 MPa / min, and the pressure was maintained for 20 min; then the powder mixture was gradually decompressed at a unloading rate of 15 MPa / min, and the powder mixture was pressed and formed; 4.2) The pressed compact was placed in a vacuum rapid hot-pressing sintering furnace, the pre-pressing force was set to 1.5 t, the initial vacuum degree was 5 Pa, the initial heating rate was set to 90℃ / min, the temperature was raised to 1000℃ and maintained for 15 min, and then the furnace was cooled, the vacuum rapid hot-pressing sintering of the compact was completed, and the TiC-Ti2Cu / Ti composite material was obtained.

[0040] Table 1 Comparison of properties of titanium-based composite materials prepared in examples and comparative examples

[0041] The mechanical properties of the composite materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested. From the test results in Table 1, it can be seen that the in-situ self-grown TiC-Ti2Cu hybrid reinforced titanium-based composite materials prepared by different process parameters have excellent strength-plasticity matching, which greatly improves the comprehensive performance of the composite materials. We balanced the size difference and density difference between PNSs and Ti powder by molecular-level blending of Cu2O coated PNSs, thereby solving the problem of uneven dispersion of high volume fraction PNSs in Ti matrix powder, and further making the in-situ self-grown TiC and Ti2Cu reinforcing bodies uniformly distributed in the intracrystalline, better capturing and storing dislocations, improving the dislocation storage capacity of the composite material and relieving stress concentration during deformation to obtain good fracture elongation. At the same time, the in-situ self-grown nano-TiC and Ti2Cu at the PNSs@Cu2O interface obtain a good interface with the Ti matrix, thereby obtaining excellent mechanical strengthening effect.

[0042] In conclusion, the above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanium thermal reaction, characterized in that, The method steps are as follows: (1) Preparation of polypyrrole spheres (PNSs) Anhydrous ferric chloride was dissolved in deionized water, and then pyrrole was added dropwise. The mixed solution was magnetically stirred, washed, filtered, and dried to prepare polypyrrole spheres (PNSs) powder. (2) Preparation of PNSs@Cu2O PNSs powder was dispersed in copper acetate solution, then sodium hydroxide solution was added dropwise, followed by glucose solution. The mixture was then magnetically stirred, heated, washed, filtered, and dried to prepare PNSs@Cu2O powder. (3) Preparation of PNSs@Cu2O / Ti-based composite powder PNSs@Cu2O powder was ultrasonically dispersed in an ethanol solution to obtain a PNSs@Cu2O suspension. Then, Ti matrix powder was added to the PNSs@Cu2O suspension, stirred and mixed evenly, and then ball-milled and vacuum-dried to obtain PNSs@Cu2O / Ti-based composite powder. (4) Preparation of TiC-Ti2Cu / Ti-based composite bulk PNSs@Cu2O / Ti-based composite powder was molded into a cylindrical compact, which was then transferred into a vacuum hot pressing sintering furnace for sintering to obtain a solidified TiC-Ti2Cu / Ti-based composite block.

2. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The specific steps for preparing polypyrrole spheres in step (1) are as follows: FeCl3 was dissolved in deionized water and ultrasonically dispersed evenly. Then, pyrrole solution was added dropwise to the FeCl3 solution. The solution was then heated in a magnetically stirred water bath at 25-60℃ and magnetically stirred for 8-36 hours to obtain a PNSs suspension. Subsequently, the suspension was vacuum filtered and washed 6-8 times alternately with deionized water and ethanol until the filtrate was colorless and neutral; then it was dried under vacuum at 40-75°C for 4-12 hours to finally obtain black powder PNSs.

3. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The specific steps for preparing PNSs@Cu2O (2) are as follows: Cu(CH3COO)2·H2O, NaOH, and CH2OH(CHOH)4CHO are dissolved in deionized water and ultrasonically dispersed evenly. PNSs are dispersed in the (Cu(CH3COO)2·H2O) suspension and NaOH solution is added dropwise. Then, glucose (CH2OH(CHOH)4CHO) solution is added dropwise. The resulting suspension is heated at 70-80℃ and stirred until the suspension turns completely brick red. The suspension is then kept warm and magnetically stirred for 30 minutes to obtain the PNSs@Cu2O suspension. After the reaction, the suspension is washed with deionized water and the filtrate is colorless and neutral. The suspension is vacuum filtered and then dried under vacuum at 60-70℃ for 4-6 hours to obtain the prepared brick red powder PNSs@Cu2O.

4. A method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1 or 2, characterized in that: In step (1), the molar ratio of anhydrous ferric chloride to pyrrole is 1-3:5-16.

5. A method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1 or 3, characterized in that: In step (2), the molar ratio of copper acetate, sodium hydroxide, and glucose is 3:5:3, and the concentration of copper acetate in the aqueous solution is 3-15 mg / mL.

6. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanium thermal reaction according to claim 1, characterized in that: The titanium matrix powder in step (3) includes one or more of pure titanium powder and Ti6Al4V alloy powder, and the particle size of the titanium matrix powder is preferably 15-53 μm; the mass percentage of PNSs@Cu2O added is 2%~3.5%.

7. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The stirring in step (3) is carried out by magnetic stirring at a stirring rate of 400-800 r / min for 15-45 min and a frequency of 30-60 KHz; the ball milling ball-to-material ratio is 10:1~15:1; the ball milling time is 120 min~180 min; and the ball milling speed is 200 r / min~250 r / min.

8. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The drying in step (3) is carried out by 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 h and the flask rotation speed is 20-200 r / min.

9. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The specific steps of pressing the compact in step (4) are as follows: PNSs@Cu2O / Ti composite powder is loaded into a graphite mold, the graphite mold containing the powder mixture is placed in a hydraulic press, the pre-pressure is set to 30-50 MPa, and the pressure is gradually increased to 30-50 MPa at 5-10 MPa / min, and the pressure is held for 10-30 min; then the pressure is gradually reduced at 10-20 MPa / min to complete the pressing and forming of the powder mixture.

10. The method for preparing high-strength and tough TiC-Ti2Cu / titanium-based composite materials based on titanothermic reaction according to claim 1, characterized in that: The specific steps of sintering in step (4) are as follows: the pressed blank is placed in a vacuum rapid hot pressing sintering furnace with a preset pressure of 1.5t, an initial vacuum degree of ≤5 Pa, an initial heating rate of 80-100℃ / min, and a holding time of 5-15min when the temperature reaches 850-1000℃. After that, the blank is cooled with the furnace to complete the vacuum rapid hot pressing sintering of the blank.

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