A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material

Abstract

This invention relates to a method for preparing a high-heat-resistant and high-wear-resistant titanium-based composite material, belonging to the field of titanium-based composite material preparation technology. First, a mixture of reinforcing precursor and titanium-based metal powder is pre-pressed to obtain a compact. Then, the compact is sintered, causing the reinforcing precursor to form TiC and TiN two-phase reinforcements in situ on the titanium-based metal powder, thus obtaining a TiC-TiN / titanium-based composite material block. Next, the TiC-TiN / titanium-based composite material block undergoes a two-step rolling hot deformation treatment to achieve the oriented distribution of the TiC and TiN two-phase reinforcements within the grains of the titanium-based metal, thereby obtaining a high-heat-resistant and high-wear-resistant titanium-based composite material. The method described in this invention is simple to operate, inexpensive, highly practical, and easy to scale up for production. It can prepare titanium-based composite materials that combine high-temperature mechanical properties with wear resistance, providing guidance for the research and development of advanced high-heat-resistant and high-wear-resistant titanium-based composite materials, and has significant application value.

Description

Technical Field

[0001] This invention relates to a method for preparing a high heat-resistant and high wear-resistant titanium-based composite material, belonging to the field of titanium-based composite material preparation technology. Background Technology

[0002] Titanium matrix composites (TMCs) have been widely used in aerospace, space technology, and weaponry due to their advantages such as high specific strength, low density, friction resistance, and corrosion resistance. However, at high temperatures, titanium alloys are prone to grain embrittlement and second-phase coarsening, leading to a significant decrease in their high-temperature mechanical properties. Furthermore, titanium alloys are susceptible to adhesive wear during friction, failing to meet service requirements. In contrast, the reinforcing phase in TMCs effectively suppresses grain boundary rotation and migration under high-temperature conditions, preventing grain coarsening and maintaining excellent high-temperature mechanical properties. The high-hardness ceramic reinforcing particles form protective wear debris during wear, acting as a lubricant and further reducing the coefficient of friction. In addition, the uniform distribution of ceramic particles within the metal matrix can withstand and disperse external loads, reducing localized plastic deformation of the matrix material and thus improving wear resistance.

[0003] In the preparation of titanium-based composites, two common methods are the external addition method and the in-situ self-generation method. The external addition method involves directly incorporating the reinforcement into the matrix through mechanical blending or stirring. However, this method often faces problems such as uneven reinforcement dispersion, weak interfacial bonding, and interfacial contamination, making it difficult to achieve ideal mechanical properties. The in-situ self-generation method, on the other hand, generates the reinforcement through internal reactions within the material, better addressing dispersion and interfacial bonding issues and ensuring excellent overall mechanical properties. Therefore, the in-situ self-generation method shows greater potential in the preparation of titanium-based composites.

[0004] Current research focuses on the in-situ generation of single ceramic reinforcing phases (such as TiC, TiB, TiN, etc.). While these single reinforcing phases are effective in improving a specific material property (such as heat resistance or strength), they cannot simultaneously enhance both heat resistance and wear resistance. Furthermore, current methods for generating ceramic reinforcing phases through in-situ reactions require high temperatures (e.g., exceeding 1200℃), which can easily lead to grain growth in the titanium matrix, reducing the overall strength of the material and hindering the preparation of high-performance titanium-based composite materials. Summary of the Invention

[0005] To address the current challenge of simultaneously improving the high-temperature mechanical and frictional properties of TMCs, this invention provides a method for preparing a high-heat-resistant and high-wear-resistant titanium-based composite material. This method involves in-situ generation of two ceramic phases, TiC and TiN, on a titanium matrix as reinforcements, combined with a two-step rolling hot deformation process to achieve a uniform and oriented distribution of the two ceramic reinforcement phases within the grains of the titanium-based composite material, thereby obtaining a titanium-based composite material with excellent mechanical and wear-resistant properties.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material includes the following steps:

[0008] (1) First, the reinforcing precursor is mixed with titanium-based metal powder evenly. Then, the mixed powder is pre-pressed to obtain a compact. The compact is then sintered so that the reinforcing precursor generates TiC and TiN two-phase reinforcements in situ on the titanium-based metal powder, resulting in a titanium-based composite block reinforced by TiC and TiN, which is abbreviated as TiC-TiN / titanium-based composite block.

[0009] (2) The TiC-TiN / titanium-based composite material block is subjected to a first-step rolling hot deformation treatment, so that TiC and TiN migrate into the grain with the grain boundary during the first-step rolling hot deformation process; then the TiC-TiN / titanium-based composite material block after the first-step rolling hot deformation treatment is subjected to a second-step rolling hot deformation treatment, so that TiC and TiN are oriented and distributed in the grain along the rolling direction during the second-step rolling hot deformation process. Through the two-step rolling hot deformation treatment, the two-phase reinforcement of TiC and TiN is oriented and distributed in the grain of titanium-based metal, and a high heat-resistant and high wear-resistant titanium-based composite material is obtained.

[0010] Furthermore, in the high heat-resistant and high wear-resistant titanium-based composite material, the sum of the mass percentages of TiC and TiN is 2% to 3.5%.

[0011] Furthermore, the preparation of TiC-TiN / titanium-based composite bulk materials using polypyrrole spheres (PNSs) as reinforcing precursors specifically includes the following steps:

[0012] PNSs were uniformly dispersed in an organic solvent to obtain a PNSs suspension; titanium-based metal powder was added to the PNSs suspension and mixed evenly, and then dried under vacuum to remove the organic solvent to obtain PNSs / titanium-based metal mixed powder.

[0013] First, the PNSs / titanium-based metal mixed powder is pre-pressed to obtain a compact. Then, the compact is transferred into a vacuum rapid hot pressing sintering furnace for sintering to obtain a TiC-TiN / titanium-based composite material block.

[0014] Further, after adding titanium-based metal powder to the PNSs suspension, the mixture is stirred and mixed evenly, then transferred to a ball mill jar for ball milling, and then dried under vacuum to remove organic solvents, to obtain PNSs / titanium-based metal mixed powder.

[0015] The ball milling process parameters include: a ball-to-material ratio of 10:1 to 15:1, a ball milling speed of 200 r / min to 250 r / min, and a ball milling time of 120 min to 180 min.

[0016] Furthermore, the sintering process parameters of the compact in the vacuum rapid hot pressing sintering furnace include: sintering temperature of 850℃~1000℃, sintering pressure of 30MPa~50MPa, and sintering time of 10min~30min; more preferably, the temperature is raised to 850℃~1000℃ at a heating rate of 80℃ / min~100℃ / min.

[0017] Furthermore, PNSs can be prepared by the following method: FeCl3 is dissolved in water to form a brownish-yellow solution, and then pyrrole solution is added dropwise until the brownish-yellow solution turns black. The black solution is then stirred at 25℃~60℃ for 8h~36h. After filtration, the collected solid is washed and dried to obtain black powdered PNSs.

[0018] Furthermore, 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 mg / mL–15 mg / mL.

[0019] Furthermore, the titanium-based metal powder is one or more of pure titanium powder or titanium alloy powder (such as Ti-50Nb titanium alloy powder, Ti-6Ni-4Zr-2Mo titanium alloy powder, Ti6Al4V alloy powder, etc.). The particle shape of the titanium-based metal powder can be any regular shape or any irregular shape, preferably spherical. The particle size of the titanium-based metal powder is preferably 10μm to 60μm.

[0020] Furthermore, the mixture of the reinforcing precursor and titanium-based metal powder is pre-pressed to form a compact, specifically including the following steps:

[0021] The mixture of the reinforcing precursor and titanium-based metal powder is loaded into a mold, and then the mold is placed in a hydraulic press. The pressure is gradually increased from 5 MPa / min to 10 MPa / min to 30 MPa to 50 MPa. After holding the pressure at 30 MPa to 50 MPa for 10 min to 30 min, the pressure is gradually reduced from 10 MPa / min to 20 MPa / min to obtain the compact.

[0022] Furthermore, the first step of the rolling hot deformation treatment adopts a high-temperature differential rolling process, specifically including the following process parameters: the initial rolling temperature is 850℃~950℃; the circumferential speed ratio of the upper and lower rolls is controlled at 1.02~1.2, and the rotation speed is 30mm / s~90mm / s; the deformation amount per pass is 8%~15%, and the total deformation amount is 16%~45%; the reflow temperature between each pass is 850℃~950℃.

[0023] Furthermore, the second step of rolling hot deformation treatment adopts a low-temperature constant speed rolling process, specifically including the following process parameters: the initial rolling temperature is 450℃~550℃; the circumferential speed of the upper and lower rolls is the same, and the rotation speed is 30mm / s~90mm / s; the deformation amount per pass is 8%~15%, and the total deformation amount is 35%~85%; the reflow temperature between each pass is 450℃~550℃.

[0024] Beneficial effects:

[0025] (1) This invention uses two ceramic phases, TiC and TiN, generated in situ, as reinforcements. The two phases can form good thermodynamic compatibility in the material matrix, effectively reducing interface defects. Among them, the high temperature stability of TiN can effectively prevent the softening of the composite material at high temperature, while inhibiting the occurrence of interface reactions and improving the overall heat resistance; the high hardness of TiC enables it to resist surface damage during friction, while the chemical stability provided by TiN can reduce oxidation or chemical wear under friction conditions. Therefore, the combination of the two can simultaneously improve the high temperature strength and wear resistance of the composite material.

[0026] (2) This invention achieves a uniformly oriented distribution of the reinforcing phase within the matrix through a two-step rolling hot deformation process. Combined with the synergistic effect of TiC and TiN ceramic reinforcing phases, it achieves dual optimization of thermodynamic stability and mechanical properties at the microscopic level. On one hand, the oriented arrangement of the reinforcing phases enables them to better prevent dislocation movement at high temperatures, improving the high-temperature creep resistance of the matrix. Simultaneously, the oriented interfaces between the reinforcing phases reduce areas of thermal stress concentration, improving the thermal stability of the material. On the other hand, the oriented TiC and TiN can provide a uniform hardened friction surface layer under friction conditions, reducing localized cracking or detachment during wear, thereby improving wear resistance.

[0027] (3) Compared with traditional carbon nanomaterials (carbon nanotubes, graphene), this invention uses zero-dimensional polymer PNSs as a reinforcing precursor. PNSs are simple to prepare, inexpensive, have high yield, and are easy to scale up. Moreover, PNSs can react in situ with titanium-based metals during subsequent sintering to simultaneously produce two nano-ceramic phases, TiC and TiN. In addition, PNSs have abundant functional groups on their surface and have a high chemical potential, enabling them to undergo in-situ reactions at relatively low temperatures. At the same time, their oxygen elements will also dissolve in the titanium matrix to achieve a solid solution strengthening effect, thereby providing mechanical strengthening to the composite material.

[0028] (4) During the mixing process of PNSs and titanium-based metal powder, ball milling can plastically deform the titanium-based metal powder to a certain extent, thereby increasing its specific surface area, which is conducive to achieving a more uniform distribution of high-quality PNSs; in addition, plastic deformation of titanium-based metal powder to a certain extent is also conducive to further improving the strength of sintered blocks.

[0029] (5) The method described in this invention is simple to operate, inexpensive, practical, and easy to scale up. It can prepare titanium-based composite materials that take into account both high-temperature mechanical properties and wear resistance, and provides guidance for the research on the development of advanced high-heat-resistant and high-wear-resistant titanium-based composite materials. Therefore, this invention has important application value. Attached Figure Description

[0030] Figure 1 The images show the TEM (transmission electron microscope) image and the energy spectrum of carbon, nitrogen and oxygen element distribution of the PNSs prepared in step (1) of Example 1.

[0031] Figure 2 The images are low-magnification and high-magnification SEM (scanning electron microscope) images of the PNSs / Ti mixed powder in step (2) of Example 1.

[0032] Figure 3 The image shows the surface SEM image of the TiC-TiN / Ti composite material in step (4) of Example 1.

[0033] Figure 4 The friction coefficients of the TiC-TiN / Ti6Al4V composite material (a) in step (4) of Example 3 and the Ti6Al4V matrix material (b) in step (2) of Comparative Example 4 are compared at 300°C.

[0034] Figure 5 The image shows a comparison of the three-dimensional morphology of the TiC-TiN / Ti6Al4V composite material (a) in step (4) of Example 3 and the Ti6Al4V matrix material (b) in step (2) of Comparative Example 4, under 300°C.

[0035] Figure 6The images are TEM images of different regions of the TiC-TiN / Ti composite material in step (4) of Example 1. Detailed Implementation

[0036] 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.

[0037] In the following embodiments:

[0038] Anhydrous ferric chloride (FeCl3, 99.9%), pyrrole (C4H5N, 99%), Shanghai Aladdin Reagent Co., Ltd.

[0039] The titanium-based metal powder is in the form of flakes or near spherical particles, with a particle size of 10μm to 60μm and a purity of 98.5wt.%, produced by Ganzhou Jingke Technology Co., Ltd.

[0040] Example 1

[0041] A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material includes the following steps:

[0042] (1) Preparation of PNSs

[0043] 1.1) Dissolve 0.1 mol of anhydrous ferric chloride (FeCl3) in 3000 mL of deionized water and sonicate for 30 min to obtain a brownish-yellow solution; then add 0.5 mol of pyrrole dropwise to the brownish-yellow solution until the brownish-yellow solution turns black; then place the black solution in a magnetically stirred water bath and stir for 10 h under water bath heating at 30℃ to obtain a PNSs suspension;

[0044] 1.2) The PNSs suspension was vacuum filtered. The collected solid was washed six times alternately with deionized water and ethanol until the filtrate was colorless and neutral. The washed solid was then placed in a vacuum drying oven and dried at 50°C for 6 hours to obtain black powdered PNSs. The microstructure of the PNSs is characterized as follows: Figure 1 As shown;

[0045] (2) Preparation of PNSs / Ti mixed powder

[0046] 2.1) Weigh 0.6g of PNSs solid powder and add it to 200mL of ethanol solution. Disperse the PNSs by ultrasonic power at 1000W for 30min to make the PNSs disperse evenly and obtain a PNSs suspension.

[0047] 2.2) 99.4 g of spherical pure titanium powder was added to the PNSs suspension and stirred until homogeneous. The mixture was then transferred to a ball mill jar, with a ball-to-powder ratio of 10:1 and a milling speed of 200 r / min. Milling was performed for 2.5 h. The powder was then transferred to a vacuum rotary evaporator and dried in a 50°C water bath at 100 r / min for 3 h to remove the ethanol solvent, yielding a PNSs / Ti mixed powder. The microstructure of the PNSs / Ti mixed powder is characterized as follows: Figure 2 As shown;

[0048] (3) Preparation of TiC-TiN / Ti composite bulk

[0049] 3.1) 50g of PNSs / Ti mixed powder is loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The mold is then placed in a hydraulic press and the pressure is gradually increased to 50MPa under a loading condition of 5MPa / min and held for 10min. Then, the pressure is gradually reduced under an unloading condition of 10MPa / min. The PNSs / Ti mixed powder is then pre-pressed to obtain a compact.

[0050] 3.2) The compact is placed in a vacuum rapid hot pressing sintering furnace and heated to 950°C at a heating rate of 100°C / min. During the heating process, the pressure is slowly increased to 50MPa and held at the temperature and pressure for 15min to allow PNSs to form TiC and TiN two-phase reinforcements in situ on pure titanium powder. Then, the compact is cooled with the furnace to obtain TiC-TiN / Ti composite material block.

[0051] (4) Thermal deformation of TiC-TiN / Ti composite bulk

[0052] First, a high-temperature differential rolling process is used to perform a first-step rolling hot deformation treatment on the TiC-TiN / Ti composite material block. This allows TiC and TiN to migrate into the grain interior along with the grain boundaries during the first-step rolling hot deformation process. Then, a low-temperature constant-speed rolling process is used to perform a second-step rolling hot deformation treatment on the TiC-TiN / Ti composite material block after the first-step rolling hot deformation treatment. This allows TiC and TiN to be oriented and distributed within the grain interior along the rolling direction during the second-step rolling hot deformation process. This completes the preparation of the high-heat-resistant and high-wear-resistant titanium-based composite material. The microstructure characterization of the obtained high-heat-resistant and high-wear-resistant titanium-based composite material (abbreviated as TiC-TiN / Ti composite material) is as follows: Figure 3 and Figure 6 As shown;

[0053] The process parameters for high-temperature differential rolling include: initial rolling temperature of 850℃, circumferential speed ratio of upper and lower rolls of 1.2, circumferential speed of rolls (or roll rotation speed) of 90mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 850℃, and reflow holding time between passes of 2min.

[0054] The process parameters for low-temperature constant speed rolling include: initial rolling temperature of 450℃, same circumferential speed of upper and lower rolls, roll rotation speed (or roll circumferential speed) controlled at 60mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 450℃, and reflow holding time between passes of 5min.

[0055] Depend on Figure 1 It can be seen that the prepared PNSs have a spherical structure and exhibit localized roughness on their surface. Furthermore, according to... Figure 1 The elemental distribution characterization results show that PNSs contain abundant carbon and nitrogen elements. When PNSs are used as precursors for reinforcement, these unique profile configurations and abundant nitrogen doping can enhance interfacial adhesion and improve interfacial strength. Furthermore, PNSs can provide the necessary carbon and nitrogen sources for in-situ authigenic TiC and TiN.

[0056] from Figure 2 As can be seen, after ball milling and mixing, the titanium powder and PNSs are mixed evenly, and the PNSs are evenly dispersed on the surface of the Ti powder without obvious agglomeration.

[0057] from Figure 3 As can be seen, the directional arrangement of nano-reinforcing phases along the rolling direction can improve the stiffness and strength of the composite material in that direction, and the arrangement of the reinforcing phases along the crack propagation direction can prevent or slow down crack propagation, thereby improving the strength and toughness of the material.

[0058] from Figure 6 As can be seen, intragranular dispersed TiC and TiN were successfully obtained by controlling the distribution of the reinforcing phase through hot deformation, with some reinforcing phases distributed along the rolling direction. During hot deformation, nanoscale in-situ self-generated TiC and TiN ceramic reinforcing particles rotate and migrate with the grain boundaries and separate from the grain boundaries within the grains. They tend to concentrate within the grains and have good interfacial bonding with the matrix, reducing interfacial defects and thus improving the overall strength, toughness, and stability of the composite material. Good interfacial bonding avoids problems such as interfacial debonding, improving the reliability of the material under high temperature and dynamic loads. Furthermore, the presence of intragranular reinforcing phases can share external loads, making the matrix less prone to plastic deformation, thereby improving the material's resistance to wear. During friction, the reinforcing phases can withstand greater loads, reducing stress concentration in the matrix and thus reducing fatigue wear, which is beneficial for improving the room temperature-high temperature performance and friction properties of titanium-based composite materials.

[0059] Example 2

[0060] Based on Example 1, the mass of PNSs solid powder was changed from 0.6g to 0.5g and the mass of spherical titanium powder was changed from 99.4g to 99.5g. Other steps and process conditions were the same as in Example 1, and a TiC-TiN / Ti composite material with high heat resistance and high wear resistance was obtained accordingly.

[0061] Example 3

[0062] Based on Example 1, the only difference is that the titanium-based metal powder is replaced with Ti6Al4V alloy powder instead of pure titanium metal powder. All other steps and process conditions are the same as in Example 1, resulting in a TiC-TiN / Ti6Al4V composite material with high heat resistance and high wear resistance.

[0063] Example 4

[0064] Based on Example 1, the only difference is that the titanium-based metal powder is replaced with Ti-50Nb alloy powder instead of pure titanium metal powder. All other steps and process conditions are the same as in Example 1, resulting in a TiC-TiN / Ti-50Nb composite material with high heat resistance and high wear resistance.

[0065] Comparative Example 1

[0066] (1) Weigh 2.5g of TiC solid powder and add it to 2000mL of ethanol solution. Disperse it under ultrasonic power of 1000W for 30min to obtain TiC suspension;

[0067] (2) 97.5g of spherical pure titanium powder was added to TiC suspension and stirred at a stirring rate of 350r / min for 10min. Then it was transferred to a vacuum rotary evaporator and dried in a constant temperature water bath at 50℃ at a rotation speed of 100r / min for 3h to remove ethanol solvent, thus obtaining TiC / Ti mixed powder.

[0068] (3) 50g of TiC / Ti mixed powder is loaded into a cylindrical hard alloy mold with a diameter of 30mm. Then the mold is placed in a hydraulic press and the pressure is gradually increased to 50MPa under a loading condition of 5MPa / min and held for 10min. Then the pressure is gradually reduced under an unloading condition of 10MPa / min. The TiC / Ti mixed powder is then pre-pressed to obtain a compact.

[0069] (4) The compact is placed in a vacuum rapid hot pressing sintering furnace and heated to 950°C at a heating rate of 100°C / min. During the heating process, the pressure is slowly increased to 50MPa and held at the temperature and pressure for 15min to obtain TiC / Ti composite material block.

[0070] (5) First, the TiC / Ti composite material block is subjected to the first step of rolling heat deformation treatment by high temperature differential rolling process, and then the TiC / Ti composite material block after the first step of rolling heat deformation treatment is subjected to the second step of rolling heat deformation treatment by low temperature constant speed rolling, so as to obtain TiC / Ti composite material.

[0071] The process parameters for high-temperature differential rolling include: initial rolling temperature of 850℃, circumferential speed ratio of upper and lower rolls of 1.2, circumferential speed of rolls (or roll rotation speed) of 90mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 850℃, and reflow holding time between passes of 2min.

[0072] The process parameters for low-temperature constant speed rolling include: initial rolling temperature of 450℃, same circumferential speed of upper and lower rolls, roll rotation speed (or roll circumferential speed) controlled at 60mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 450℃, and reflow holding time between passes of 5min.

[0073] Comparative Example 2

[0074] (1) Weigh 2.5g of TiN solid powder and add it to 2000mL of ethanol solution. Disperse it under ultrasonic power of 1000W for 30min to obtain TiN suspension;

[0075] (2) 97.5g of spherical pure titanium powder was added to TiN suspension and stirred at a stirring rate of 350r / min for 10min. Then it was transferred to a vacuum rotary evaporator and dried in a constant temperature water bath at 50℃ at a rotation speed of 100r / min for 3h to remove ethanol solvent, so as to obtain TiN / Ti mixed powder.

[0076] (3) 50g of TiN / Ti mixed powder is loaded into a cylindrical hard alloy mold with a diameter of 30mm. Then the mold is placed in a hydraulic press and the pressure is gradually increased to 50MPa under a loading condition of 5MPa / min and held for 10min. Then the pressure is gradually reduced under an unloading condition of 10MPa / min. The TiN / Ti mixed powder is then pre-pressed to obtain a compact.

[0077] (4) The compact is placed in a vacuum rapid hot pressing sintering furnace and heated to 950°C at a heating rate of 100°C / min. During the heating process, the pressure is slowly increased to 50MPa and held at the temperature and pressure for 15min to obtain TiN / Ti composite material block.

[0078] (5) First, the TiN / Ti composite material block is subjected to the first step of rolling heat deformation treatment by high temperature differential rolling process, and then the TiN / Ti composite material block after the first step of rolling heat deformation treatment is subjected to the second step of rolling heat deformation treatment by low temperature constant speed rolling, so as to obtain TiN / Ti composite material.

[0079] The process parameters for high-temperature differential rolling include: initial rolling temperature of 850℃, circumferential speed ratio of upper and lower rolls of 1.2, circumferential speed of rolls (or roll rotation speed) of 90mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 850℃, and reflow holding time between passes of 2min.

[0080] The process parameters for low-temperature constant speed rolling include: initial rolling temperature of 450℃, same circumferential speed of upper and lower rolls, roll rotation speed (or roll circumferential speed) controlled at 60mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 450℃, and reflow holding time between passes of 5min.

[0081] Comparative Example 3

[0082] (1) Weigh 2.25g of TiC solid powder and 0.25g of TiN solid powder respectively and add them to 2000mL of ethanol solution. Disperse them under ultrasonic power of 1000W for 30min to obtain TiC-TiN mixed suspension;

[0083] (2) 97.5g of spherical pure titanium powder was added to the TiC-TiN mixed suspension and stirred at a stirring rate of 350r / min for 10min. Then it was transferred to a vacuum rotary evaporator and dried in a constant temperature water bath at 50℃ at a rotation speed of 100r / min for 3h to remove the ethanol solvent, thus obtaining TiC-TiN / Ti mixed powder.

[0084] (3) 50g of TiC-TiN / Ti mixed powder is loaded into a cylindrical hard alloy mold with a diameter of 30mm. Then the mold is placed in a hydraulic press and the pressure is gradually increased to 50MPa under a loading condition of 5MPa / min and held for 10min. Then the pressure is gradually reduced under an unloading condition of 10MPa / min. The TiC-TiN / Ti mixed powder is then pre-pressed to obtain a compact.

[0085] (4) The compact is placed in a vacuum rapid hot pressing sintering furnace and heated to 950°C at a heating rate of 100°C / min. During the heating process, the pressure is slowly increased to 50MPa and held at the temperature and pressure for 15min to obtain TiC-TiN / Ti composite material block.

[0086] (5) First, the TiC-TiN / Ti composite material block is subjected to the first step of rolling heat deformation treatment by high temperature differential rolling process, and then the TiC-TiN / Ti composite material block after the first step of rolling heat deformation treatment is subjected to the second step of rolling heat deformation treatment by low temperature constant speed rolling, so as to obtain TiC-TiN / Ti composite material.

[0087] The process parameters for high-temperature differential rolling include: initial rolling temperature of 850℃, circumferential speed ratio of upper and lower rolls of 1.2, circumferential speed of rolls (or roll rotation speed) of 90mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 850℃, and reflow holding time between passes of 2min.

[0088] The process parameters for low-temperature constant speed rolling include: initial rolling temperature of 450℃, same circumferential speed of upper and lower rolls, roll rotation speed (or roll circumferential speed) controlled at 60mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 450℃, and reflow holding time between passes of 5min.

[0089] Comparative Example 4

[0090] (1) Preparation of Ti6Al4V bulk material

[0091] 1.1) 50g of Ti6Al4V powder is loaded into a cylindrical cemented carbide mold with a diameter of 30mm. The mold is then placed in a hydraulic press and the pressure is gradually increased to 50MPa under a loading condition of 5MPa / min and held for 10min. Then the pressure is gradually reduced under an unloading condition of 10MPa / min. The Ti6Al4V powder is then pre-pressed to obtain a compact.

[0092] 1.2) The compact is placed in a vacuum rapid hot pressing sintering furnace and heated to 950°C at a heating rate of 100°C / min. During the heating process, the pressure is slowly increased to 50MPa and held at the temperature and pressure for 15min to obtain Ti6Al4V block.

[0093] (2) Thermal deformation of Ti6Al4V bulk material

[0094] First, a high-temperature differential rolling process is used to perform the first step of rolling heat deformation treatment on the Ti6Al4V block. Then, a low-temperature constant speed rolling process is used to perform the second step of rolling heat deformation treatment on the Ti6Al4V block after the first step of rolling heat deformation treatment, thus obtaining the Ti6Al4V matrix material.

[0095] The process parameters for high-temperature differential rolling include: initial rolling temperature of 850℃, circumferential speed ratio of upper and lower rolls of 1.2, circumferential speed of rolls (or roll rotation speed) of 90mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 850℃, and reflow holding time between passes of 2min.

[0096] The process parameters for low-temperature constant speed rolling include: initial rolling temperature of 450℃, same circumferential speed of upper and lower rolls, roll rotation speed (or roll circumferential speed) controlled at 60mm / s, deformation per pass of 10%, total deformation of 40%, reflow temperature between passes of 450℃, and reflow holding time between passes of 5min.

[0097] The tribological properties of the TiC-TiN / Ti6Al4V composite material prepared in Example 3 and the Ti6Al4V matrix material prepared in Comparative Example 4 were tested. Figure 4 The test results show that the friction coefficient of the TiC-TiN / Ti6Al4V composite material decreased by about 20% compared to the Ti6Al4V matrix material at high temperatures. This reduction in friction coefficient means that, under the same conditions, the heat and energy loss generated during friction are reduced, thus reducing wear. According to... Figure 5 The test results show that at high temperatures, the friction surface of the Ti6Al4V matrix material exhibits grooves, spalling, and pits, indicating adhesive wear and abrasive wear. In contrast, the friction marks of the TiC-TiN / Ti6Al4V composite material are smooth and even, indicating that its friction behavior is significantly better than that of the Ti6Al4V matrix material. This is because the TiC and TiN reinforcing particles generated by the in-situ self-generation technology are evenly distributed and have good interfacial bonding performance, which can avoid interfacial delamination, enhance the bonding between the matrix phase and the ceramic reinforcing phase, thereby improving the overall friction performance of the material and avoiding wear aggravation caused by uneven distribution or poor interfacial bonding.

[0098] The mechanical properties of the composite materials prepared in Examples 1-4 and Comparative Examples 1-4 were tested. The test results summarized in Table 1 show that the titanium-based composite materials in Examples 1-4, based on in-situ self-generated TiC-TiN synergistic reinforcement, achieved excellent strength-ductility matching at room temperature and maintained excellent high-temperature mechanical properties, significantly improving the overall performance of the composite materials. This is because the in-situ self-generated TiC and TiN reinforcements are uniformly distributed within the grains, which can better capture and store dislocations, improving the dislocation storage capacity of the composite material and alleviating stress concentration during deformation to obtain good fracture elongation. Simultaneously, the in-situ self-generated nano-TiC and TiN can significantly improve the interfacial bonding strength between the reinforcement and the titanium-based metal matrix, thereby obtaining excellent mechanical strengthening effects. Furthermore, the in-situ self-generated TiC and TiN can suppress grain boundary migration and rotation during high-temperature tensile deformation, resulting in superior high-temperature mechanical properties.

[0099] Table 1

[0100]

[0101] The tribological properties of the composite materials prepared in Examples 1-4 and Comparative Examples 1-4 were tested. The test results summarized in Table 2 show that the titanium-based composite materials in Examples 1-4, based on in-situ self-generated TiC-TiN synergistic reinforcement, achieved excellent tribological properties at high temperatures. This is due to the high hardness of TiC and the high-temperature stability of TiN forming a hard ceramic protective layer, effectively preventing wear of the matrix material during friction. Simultaneously, the strong interfacial bonding of the in-situ generated reinforcing phase reduces the shedding of reinforcing phase particles during friction, thus reducing wear. Furthermore, the low friction and anti-adhesion properties of TiN significantly reduce the coefficient of friction in high-temperature friction, preventing drastic fluctuations in the coefficient of friction due to temperature increases. TiN also exhibits excellent oxidation resistance, forming a protective oxide layer during high-temperature friction, delaying oxidative wear on the material surface. The chemical stability of TiN effectively prevents chemical reactions on the friction surface under high-temperature conditions, thereby reducing chemical wear.

[0102] Table 2

[0103]

[0104] Therefore, based on the characterization results above, it can be seen that the titanium-based composite material based on in-situ self-generated TiC-TiN synergistic reinforcement prepared by the method described in this invention achieves simultaneous improvement in mechanical and frictional properties.

[0105] 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 a high heat-resistant and high wear-resistant titanium-based composite material, characterized in that: Includes the following steps: (1) First, the reinforcing precursor is mixed with titanium-based metal powder evenly. Then, the mixed powder is pre-pressed to obtain a compact. The compact is then sintered so that the reinforcing precursor generates TiC and TiN two-phase reinforcements in situ on the titanium-based metal powder, thus obtaining a TiC-TiN / titanium-based composite block reinforced by TiC and TiN. (2) The TiC-TiN / titanium-based composite material block is subjected to a first-step rolling hot deformation treatment, so that TiC and TiN migrate into the grain with the grain boundary during the first-step rolling hot deformation process; then the TiC-TiN / titanium-based composite material block after the first-step rolling hot deformation treatment is subjected to a second-step rolling hot deformation treatment, so that TiC and TiN are oriented and distributed in the grain along the rolling direction during the second-step rolling hot deformation process, thereby obtaining a high heat-resistant and high wear-resistant titanium-based composite material. Among them, the precursor of the reinforcing agent is polypyrrole spheres; The first step of the rolling hot deformation treatment adopts a high-temperature differential rolling process, specifically including the following process parameters: the initial rolling temperature is 850℃~950℃; the circumferential speed ratio of the upper and lower rolls is controlled at 1.02~1.2, and the rotation speed is 30mm / s~90mm / s; the deformation amount per pass is 8%~15%, and the total deformation amount is 16%~45%; the reflow temperature between each pass is 850℃~950℃. The second step of hot deformation treatment uses a low-temperature constant speed rolling process, which includes the following process parameters: the initial rolling temperature is 450℃~550℃; the circumferential speed of the upper and lower rolls is the same, and the rotation speed is 30mm / s~90mm / s; the deformation amount per pass is 8%~15%, and the total deformation amount is 35%~85%; the reflow temperature between each pass is 450℃~550℃.

2. The method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to claim 1, characterized in that: In high heat-resistant and high wear-resistant titanium-based composite materials, the sum of the mass percentages of TiC and TiN is 2% to 3.5%.

3. The method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to claim 1, characterized in that: The preparation of TiC-TiN / titanium-based composite bulk materials using polypyrrole spheres as reinforcing precursors specifically includes the following steps: Polypyrrole spheres were uniformly dispersed in an organic solvent to obtain a polypyrrole sphere suspension; titanium-based metal powder was added to the polypyrrole sphere suspension and mixed evenly, and then dried under vacuum to remove the organic solvent to obtain a polypyrrole sphere / titanium-based metal mixed powder. First, the polypyrrole spheres / titanium-based metal mixed powder is pre-pressed to obtain a compact. Then, the compact is transferred into a vacuum rapid hot pressing sintering furnace for sintering to obtain a TiC-TiN / titanium-based composite material block.

4. The method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to claim 3, characterized in that: After adding titanium-based metal powder to the polypyrrole ball suspension, the mixture is stirred and mixed evenly. Then, it is transferred to a ball mill jar for ball milling and then dried under vacuum to remove organic solvents, thus obtaining polypyrrole ball / titanium-based metal mixed powder. The ball milling process parameters include: a ball-to-material ratio of 10:1 to 15:1, a ball milling speed of 200 r / min to 250 r / min, and a ball milling time of 120 min to 180 min.

5. The method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to claim 3, characterized in that: Polypyrrole spheres were prepared using the following method: FeCl3 was dissolved in water to form a brownish-yellow solution. Then, pyrrole solution was added dropwise until the brownish-yellow solution turned black. The black solution was then stirred at 25℃~60℃ for 8h~36h. After filtration, the collected solid was washed and dried to obtain black powdered polypyrrole spheres.

6. The method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to claim 5, characterized in that: The molar ratio of ferric chloride to pyrrole is 1–3:5–16; And / or, The concentration of ferric chloride in aqueous solution is 3 mg / mL to 15 mg / mL.

7. A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to any one of claims 1-6, characterized in that: The sintering process parameters of the compact in the vacuum rapid hot pressing sintering furnace include: sintering temperature of 850℃~1000℃, sintering pressure of 30MPa~50MPa, and sintering time of 10min~30min.

8. A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to any one of claims 1-6, characterized in that: Titanium-based metal powder is one or more of pure titanium powder or titanium alloy powder; And / or, The particles of titanium-based metal powder are spherical in shape; And / or, The particle size of titanium-based metal powder is 10μm to 60μm.

9. A method for preparing a high heat-resistant and high wear-resistant titanium-based composite material according to any one of claims 1-6, characterized in that: The mixture of reinforcing precursor and titanium-based metal powder is pre-compressed to form a compact, specifically including the following steps: The mixture of the reinforcing precursor and titanium-based metal powder is loaded into a mold, and then the mold is placed in a hydraulic press. The pressure is gradually increased from 5 MPa / min to 10 MPa / min to 30 MPa to 50 MPa. After holding the pressure at 30 MPa to 50 MPa for 10 min to 30 min, the pressure is gradually reduced from 10 MPa / min to 20 MPa / min to obtain the compact.

Images