A method for preparing nano-reinforced titanium matrix composites based on high-energy low-speed forming combined with high-energy high-speed remelting process

Abstract

This invention discloses a method for preparing nano-reinforced titanium-based composite materials based on a high-energy, low-speed forming combined with a high-energy, high-speed remelting process. The high-energy, low-speed scanning process during laser forming allows for the complete melting of micron-sized ceramic particles in the titanium matrix, resulting in the growth of precipitated ceramic dendrites. The solidified titanium-based composite material is then subjected to high-energy, high-speed remelting, which further refines the ceramic dendrites in the titanium matrix, generating a nanophase. This increases the uniformity and density of the nanophase within the matrix, maximizing the strengthening effect of the nanosolid solution and improving the material's mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of ceramic-reinforced titanium matrix composites, specifically a method for preparing nano-reinforced titanium matrix composites based on a high-energy low-speed forming combined with a high-energy high-speed remelting process. Background Technology

[0002] Laser-fused powder bed titanium matrix composites are widely used in aerospace, biomedicine, and other fields due to their high specific strength and excellent corrosion resistance. By selecting appropriate reinforcing phase systems and sizes, titanium matrix composites can improve material strength while maintaining their original ductility. However, the use of nanoscale ceramic particles as reinforcing phases in titanium matrices is greatly limited due to their high preparation difficulty, high cost, and tendency to agglomerate during the forming process. Although micron-sized ceramic particles are less expensive and easier to disperse uniformly in the matrix, the interfacial bonding between micron-sized ceramic reinforcing phases and the matrix is ​​poor, leading to cracking or debonding at the interface and premature material failure, thus limiting the engineering applications of micron-sized ceramic-reinforced titanium matrix composites. Summary of the Invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process, in order to maximize the strengthening effect of the generated nano solid solution and improve the mechanical properties of the material.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing nano-reinforced titanium-based composite materials based on a high-energy, low-speed forming process combined with a high-energy, high-speed remelting process includes the following steps:

[0006] (1) TiC ceramic powder and TiN ceramic powder are mixed by high-energy ball milling to obtain pre-solution TiC-TiN mixed powder;

[0007] (2) The TiC-TiN mixed powder pre-solidified in step (1) and the titanium alloy powder are ball-milled and mixed evenly under inert gas protection to obtain titanium-based composite powder;

[0008] (3) Establish a three-dimensional solid geometric model of the part, slice the model into layers, plan the laser scanning path and set the forming and remelting process, discretize the three-dimensional solid into a series of two-dimensional data, save and import it into the laser powder bed melting forming equipment;

[0009] (4) The laser powder bed melting and forming equipment melts and solidifies the titanium-based composite powder in step (2) layer by layer according to the data imported in step (3) and performs high-energy high-speed laser remelting to finally form the target three-dimensional solid part.

[0010] Specifically, in step (1), the TiC ceramic powder is a submicron-sized powder with a particle size distribution range of 0.1 to 0.6 μm and a purity greater than 99.5%.

[0011] Specifically, in step (1), the TiN ceramic powder is a micron-sized powder with a particle size distribution range of 2 to 6 μm and a purity greater than 99.5%.

[0012] Specifically, in step (1), the TiC ceramic powder and TiN ceramic powder are ball-milled and mixed under inert gas protection using a single-tank planetary high-energy ball mill with a ball-to-material ratio of 10:1, a high-energy ball milling speed of 225-275 rpm, and a ball milling time of 12-18 h. The TiC ceramic powder is coated on the surface of the TiN ceramic powder particles to prepare a pre-solution TiC-TiN mixed powder.

[0013] Specifically, in step (1), the mass ratio of TiC ceramic powder to TiN ceramic powder is 4:3 to 5:3.

[0014] Specifically, in step (2), the pre-solidified TiC-TiN mixed powder accounts for 15-20 wt.% of the total mass of the titanium-based composite powder.

[0015] Specifically, in step (2), the titanium alloy powder is a titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy, wherein the aluminum content is 6.5-7.0 wt.%, the zirconium content is 5.8-6.3 wt.%, the vanadium content is 2.0-2.2 wt.%, the molybdenum content is 2.0-2.3 wt.%, the niobium content is 0.5-0.8 wt.%, and the balance is titanium; the particle size distribution range of the titanium alloy powder is 21-57 μm.

[0016] Specifically, in step (4), the laser powder bed melting and forming equipment employs a high-energy, low-speed scanning process during laser forming, followed by high-energy, high-speed remelting of the solidified titanium-based composite material. The high-energy, low-speed scanning process during laser forming allows for the complete melting of micron-sized ceramic particles in the titanium matrix, resulting in a tendency for the precipitated ceramic dendrites to grow. The subsequent high-energy, high-speed remelting of the solidified titanium-based composite material further refines the ceramic dendrites in the titanium matrix, generating a nanophase. This increases the uniformity and density of the nano-solid solution in the matrix, maximizing the strengthening effect of the nano-solid solution and improving the material's mechanical properties.

[0017] Furthermore, in step (4), the laser power used for high-energy low-speed forming of laser powder bed melting is 250-300W, the laser scanning speed is 500-700mm / s, the scanning interval is 50μm, the powder thickness is 50μm, and a partitioned island scanning strategy is adopted.

[0018] Furthermore, in step (4), the high-energy high-speed remelting process uses a laser power of 250-300W and a laser scanning speed of 1300-1500mm / s.

[0019] The laser parameters mentioned above were determined after process optimization. Based on the microstructure and performance characteristics of titanium-based composite materials, laser remelting parameters can be rationally selected to effectively adjust the morphology, size and distribution of the nanophase, thus successfully preparing titanium-based composite materials with good forming quality and excellent comprehensive performance.

[0020] Beneficial effects:

[0021] (1) In this invention, high-energy, low-speed scanning is used during laser forming to completely melt the original micron-sized ceramic particles. Due to the slow cooling rate of the molten pool and the long liquid phase existence time, the precipitated ceramic dendrites have a significant tendency to grow. High-energy, high-speed scanning of the solidified titanium-based composite material can remelt the ceramic dendrites in the titanium matrix and significantly refine them during rapid cooling, thereby obtaining a nano-solid solution. These nano-solid solutions are uniformly dispersed and have a high distribution density in the matrix, providing a large number of effective nucleation sites, hindering grain boundary migration, increasing the nucleation rate while reducing the grain growth rate, refining the matrix grain size, and hindering dislocation movement, thus playing a dispersion strengthening role. Compared with the micron-sized ceramic reinforcing phase, the in-situ generated nano-solid solutions have better interface bonding with the matrix. Simultaneously, during the high-energy, high-speed remelting process, elements form a supersaturated solid solution in the matrix. Therefore, by using high-energy low-speed forming and high-energy high-speed remelting, the nanophase can be refined, the uniform distribution of nano-solid solutions in the matrix can be increased, the interfacial bonding strength can be improved, and the strengthening effects of dispersion strengthening, solid solution strengthening and interfacial load transfer can be achieved, thereby improving the mechanical properties of the material.

[0022] (2) The laser powder bed melting technology used in this invention to prepare ceramic-reinforced titanium-based composite materials not only shortens the production cycle, improves product production efficiency, and reduces product production costs, but also allows for the formation of parts with complex geometries with almost no subsequent machining. The cooling rate of the molten pool during laser powder bed melting is extremely high, reaching 10... 3 ~10 8 K / s effectively refines grain size and improves the mechanical properties of parts.

[0023] (3) The present invention can adjust the laser energy density by changing the laser power and laser scanning speed. As the laser energy input of the powder bed changes, the thermodynamic and kinetic characteristics of the molten pool formed by the interaction between the laser and the powder bed also change. By rationally selecting the laser forming and remelting process parameters, adjusting the laser energy input, refining the nano-phase size, and obtaining nano-reinforced titanium-based composite materials with excellent mechanical properties. Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0025] Figure 1 This is a SEM image of the titanium-based composite material sample prepared in Example 1.

[0026] Figure 2 SEM image of the Ti(C,N) nanophase formed in the titanium-based composite material prepared in Example 1.

[0027] Figure 3 This is a SEM image of the titanium-based composite material sample prepared in Example 2.

[0028] Figure 4 This is a SEM image of the titanium-based composite material sample prepared in Example 3.

[0029] Figure 5 The image shows a SEM image of the titanium-based composite material sample prepared in Comparative Example 2.

[0030] Figure 6 The image shows a SEM image of the titanium-based composite material sample prepared in Comparative Example 3.

[0031] Figure 7 The image shows a SEM image of the titanium-based composite material sample prepared in Comparative Example 4. Detailed Implementation

[0032] The present invention can be better understood from the following embodiments.

[0033] In the following examples, the titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy powder used has a particle size distribution range of 21 to 57 μm, the TiC ceramic powder used has a particle size distribution range of 0.1 to 0.6 μm and a purity greater than 99.5%, and the TiN ceramic powder used has a particle size distribution range of 2 to 6 μm and a purity greater than 99.5%.

[0034] Example 1

[0035] (1) Micron-sized TiC and TiN ceramic powders were mixed by high-energy ball milling at a mass ratio of 4:3 (ball-to-powder ratio 10:1), a high-energy ball milling speed of 250 rpm, and a milling time of 15 h. Submicron TiC was coated on the surface of micron-sized TiN particles to prepare a pre-solution TiC-TiN mixed powder. The pre-solution TiC-TiN mixed powder was then ball-milled with titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy powder under inert gas protection to obtain a titanium-based composite powder, wherein the ceramic powder accounted for 20% of the total mass of the composite powder.

[0036] (2) Target part modeling and slicing

[0037] A three-dimensional solid geometric model of the target part is created in the computer. The three-dimensional solid model is then sliced ​​into layers, a scanning path is planned, and a laser remelting process is set. The three-dimensional solid is discretized into a series of two-dimensional data, which is saved and imported into a laser powder bed melting forming equipment. The laser process parameters are set as follows: laser power of 250W, scanning speed of 500mm / s, scanning interval of 50μm, powder thickness of 50μm, and a partitioned island scanning strategy is adopted. The laser remelting process uses a laser power of 250W and a scanning speed of 1300mm / s.

[0038] (3) Laser powder bed melting process

[0039] The TiC and TiN ceramic-reinforced titanium-based composite powder obtained in step (1) was used for laser powder bed melting. An SLM-150 laser powder bed melting system was used, which mainly includes a YLR-500 fiber laser, a laser forming chamber, an automatic powder spreading system, a protective atmosphere device, a computer control circuit system, and a cooling circulation system. Before forming, the sandblasted titanium alloy substrate was fixed on the worktable of the laser powder bed melting system and leveled. Then, the forming chamber was sealed using a sealing device, evacuated, and purged with an argon protective atmosphere. A typical laser powder bed melting process is as follows: (a) The powder spreading device evenly spreads titanium-based composite powder on the forming substrate. The laser beam scans the sliced ​​area line by line according to the pre-designed scanning path, causing the powder layer to melt and solidify rapidly under high energy and low speed scanning. Then, the laser beam performs high energy and high speed remelting according to the set scanning path. After solidification, the first two-dimensional plane of the part is obtained; (b) The computer control system lowers the forming substrate by one powder layer thickness. Conversely, it raises the piston of the powder supply cylinder by a certain powder layer thickness. The powder spreading device lays a new layer of powder to be processed. The laser beam completes the second powder layer scanning and in-situ remelting according to the sliced ​​information to obtain the second two-dimensional plane of the part; (c) Repeat step (b) to form the powder to be processed layer by layer until the part is processed.

[0040] (4) After cooling, the formed substrate is removed from the equipment, and the part is separated from the substrate using wire cutting to obtain the titanium-based composite material part. The titanium-based composite material block sample is ground, polished, and etched according to the standard metallographic sample preparation method. The titanium-based composite material sample prepared by laser powder bed melting has good forming quality and a density of 99.6%. The nano-precipitated phase is uniformly distributed in the matrix with a high distribution density and no obvious agglomeration (see...). Figure 1 and Figure 2This indicates that during the high-energy, low-speed laser powder bed melting process, submicron-sized TiC and micron-sized TiN ceramic particles are completely melted, and ceramic dendrites are formed after solidification. In the subsequent high-energy, high-speed remelting process, the Ti(C,N) ceramic dendrites remelt and are refined during rapid solidification, thus maximizing the reinforcing effect of the nano-solid solution. The obtained nano-reinforced titanium-based composite material sample was tested for hardness, and the hardness was 817 HV. 0.2 .

[0041] Example 2

[0042] (1) Micron-sized TiC and TiN ceramic powders were mixed by high-energy ball milling at a mass ratio of 5:3 (ball-to-powder ratio 10:1), a high-energy ball milling speed of 225 rpm, and a milling time of 18 h. Submicron TiC was coated on the surface of micron-sized TiN particles to prepare a pre-solution TiC-TiN mixed powder. The pre-solution TiC-TiN mixed powder was then ball-milled with titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy powder under inert gas protection to obtain a titanium-based composite powder, wherein the ceramic powder accounted for 15% of the total mass of the composite powder.

[0043] (2) Target part modeling and slicing

[0044] A three-dimensional solid geometric model of the target part is created in the computer. The three-dimensional solid model is then sliced ​​into layers, a scanning path is planned, and a laser remelting process is set. The three-dimensional solid is discretized into a series of two-dimensional data, which is saved and imported into a laser powder bed melting forming equipment. The laser process parameters are set as follows: laser power of 275W, scanning speed of 600mm / s, scanning spacing of 50μm, powder thickness of 50μm, and a partitioned island scanning strategy is adopted. The laser remelting process uses a laser power of 275W and a scanning speed of 1400mm / s.

[0045] (3) Laser powder bed melting process

[0046] The TiC and TiN ceramic-reinforced titanium-based composite powder obtained in step (1) was used for laser powder bed melting. An SLM-150 laser powder bed melting system was used, which mainly includes a YLR-500 fiber laser, a laser forming chamber, an automatic powder spreading system, a protective atmosphere device, a computer control circuit system, and a cooling circulation system. Before forming, the sandblasted titanium alloy substrate was fixed on the worktable of the laser powder bed melting system and leveled. Then, the forming chamber was sealed using a sealing device, evacuated, and purged with an argon protective atmosphere. A typical laser powder bed melting process is as follows: (a) The powder spreading device evenly spreads titanium-based composite powder on the forming substrate. The laser beam scans the sliced ​​area line by line according to the pre-designed scanning path, causing the powder layer to melt and solidify under high energy and low speed scanning. Then, the laser beam performs high energy and high speed remelting according to the set scanning path. After solidification, the first two-dimensional plane of the part is obtained; (b) The computer control system lowers the forming substrate by one powder layer thickness. Conversely, it raises the piston of the powder supply cylinder by a certain powder layer thickness. The powder spreading device re-spreads a layer of powder to be processed. The laser beam completes the second powder layer scanning and in-situ remelting according to the sliced ​​information to obtain the second two-dimensional plane of the part; (c) Repeat step (b) to form the powder layer by layer until the part is processed.

[0047] (4) After cooling, the formed substrate is removed from the equipment, and the part is separated from the substrate using wire cutting to obtain the titanium-based composite material part. The titanium-based composite material block sample is ground, polished, and etched according to the standard metallographic sample preparation method. The titanium-based composite material sample prepared by laser powder bed melting has good forming quality and a density of 98.7%. The nanoparticles are uniformly distributed in the matrix. A small amount of precipitated phase was observed to grow slightly in the remelted area of ​​the molten pool, but the particle size is still relatively small (see...). Figure 3 This indicates that during the high-energy, low-speed laser powder bed melting process, the added original ceramic particles completely melt, and the resulting ceramic dendrites remelt under the action of the high-energy, high-speed laser, generating fine Ti(C,N) precipitates that are uniformly distributed in the matrix. Due to the combined effects of the high-density precipitates, supersaturated solid solution, and good interfacial bonding, the material's properties are significantly improved. The obtained nano-reinforced titanium matrix composite sample was tested for hardness, and the hardness was 789 HV. 0.2 The distribution is relatively uniform.

[0048] Example 3

[0049] (1) Micron-sized TiC and TiN ceramic powders were mixed by high-energy ball milling at a mass ratio of 3:2 (ball-to-powder ratio 10:1), a high-energy ball milling speed of 275 rpm, and a milling time of 12 h. Submicron TiC was coated on the surface of micron-sized TiN particles to prepare a pre-solution TiC-TiN mixed powder. The pre-solution TiC-TiN mixed powder was then ball-milled with titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy powder under inert gas protection to obtain a titanium-based composite powder, in which the ceramic powder accounted for 18% of the total mass of the composite powder.

[0050] (2) Target part modeling and slicing

[0051] A three-dimensional solid geometric model of the target part is created in the computer. The three-dimensional solid model is then sliced ​​into layers, a scanning path is planned, and a laser remelting process is set. The three-dimensional solid is discretized into a series of two-dimensional data, which is saved and imported into a laser powder bed melting forming equipment. The laser process parameters are set as follows: laser power of 300W, scanning speed of 700mm / s, scanning interval of 50μm, powder thickness of 50μm, and a partitioned island scanning strategy is adopted. The laser remelting process uses a laser power of 300W and a scanning speed of 1500mm / s.

[0052] (3) Laser powder bed melting process

[0053] The TiC and TiN ceramic-reinforced titanium-based composite powder obtained in step (1) was used for laser powder bed melting. An SLM-150 laser powder bed melting system was used, which mainly includes a YLR-500 fiber laser, a laser forming chamber, an automatic powder spreading system, a protective atmosphere device, a computer control circuit system, and a cooling circulation system. Before forming, the sandblasted titanium alloy substrate was fixed on the worktable of the laser powder bed melting system and leveled. Then, the forming chamber was sealed using a sealing device, evacuated, and purged with an argon protective atmosphere. A typical laser powder bed melting process is as follows: (a) The powder spreading device evenly spreads titanium-based composite powder on the forming substrate. The laser beam scans the sliced ​​area line by line according to the pre-designed scanning path, causing the powder layer to melt and solidify under high energy and low speed scanning. Then, the laser beam performs high energy and high speed remelting according to the set scanning path. After solidification, the first two-dimensional plane of the part is obtained; (b) The computer control system lowers the forming substrate by one powder layer thickness. Conversely, it raises the piston of the powder supply cylinder by a certain powder layer thickness. The powder spreading device re-spreads a layer of powder to be processed. The laser beam completes the second powder layer scanning and in-situ remelting according to the sliced ​​information to obtain the second two-dimensional plane of the part; (c) Repeat step (b) to form the powder layer by layer until the part is processed.

[0054] (4) After cooling, the formed substrate is removed from the equipment, and the part is separated from the substrate using wire cutting to obtain the titanium-based composite material part. The titanium-based composite material block sample is ground, polished, and etched according to the standard metallographic sample preparation method. The titanium-based composite material sample prepared by laser powder bed melting has good forming quality, with a density of 99.3%. No unmelted ceramic particles were observed in the titanium matrix, and the precipitated rod-shaped and round particles were relatively uniformly distributed in the matrix. Figure 4 As shown, during laser powder bed melting, TiC and TiN ceramic particles completely melt and precipitate in the matrix under a high-energy, low-speed scanning strategy. During laser remelting, the precipitated phases remelt under the action of a high-energy laser, and then precipitate again to form fine particles during rapid solidification. The obtained nano-reinforced titanium matrix composite sample was subjected to hardness testing, and the hardness was 803 HV. 0.2 The hardness values ​​fluctuated little and were relatively evenly distributed in the 5×5 matrix tested.

[0055] Comparative Example 1

[0056] This comparative example follows the same steps as Example 1, except that the TiC and TiN ceramic powders used have a particle size distribution range of 37–55 nm. In this comparative example, due to the small particle size and large specific surface area of ​​the ceramic particles, strong van der Waals forces exist between the ceramic particles, making them prone to agglomeration and difficult to disperse evenly on the matrix surface during ball milling. Simultaneously, during laser forming, the nano-ceramic particles agglomerate, resulting in uneven dispersion in the matrix and a lack of significant improvement in the strengthening effect on the matrix. The hardness of the reinforced phase-rich region is high, reaching 873 HV. 0.2 The hardness of barren areas is lower, at 724 HV. 0.2 The hardness distribution is uneven and fluctuates greatly.

[0057] Comparative Example 2

[0058] This comparative example follows the same steps as Example 1, except that the powder layer is not subjected to high-energy, high-speed remelting after high-energy, low-speed melting and solidification during laser forming. Because high-energy, high-speed laser remelting is not performed, the size of the primary ceramic dendrites in the titanium matrix grows, such as… Figure 5 As shown, the molding quality was greatly reduced, with the density decreasing to 98.1% and the hardness decreasing to 760 HV. 0.2 Furthermore, their distribution is uneven.

[0059] Comparative Example 3

[0060] This comparative example follows the same steps as Example 3, except that after the powder layer undergoes high-energy, low-speed melting-solidification, the laser beam remelts it using the same process along the set scanning path. After remelting, the titanium-based composite material showed relatively large precipitated phase sizes in the titanium matrix. Figure 6As shown. This is because, under high-energy, low-speed remelting, although the initially formed dendrites remelt, due to the low cooling rate during solidification, they grow significantly after precipitation, forming coarse ceramic dendrites. This weakens their reinforcing effect, and the hardness drops to 752 HV. 0.2 .

[0061] Comparative Example 4

[0062] This comparative example follows the same steps as Example 1, except that a pre-solidified TiC-TiN mixed powder was not used as the reinforcing phase to prepare the titanium-based composite powder. Instead, a single TiC ceramic powder was used as the reinforcing phase to prepare the titanium-based composite powder, which was then formed by laser powder bed melting. In this comparative example, even though the micron-sized TiC ceramic reinforcing phase in the titanium matrix completely melted to form TiC dendrites, they tended to grow during solidification, with lengths ranging from submicron to micron. No nanoscale precipitates were observed. Due to the high brittleness of TiC dendrites and their poor bonding with the matrix interface, microcracks were generated at the interface. Figure 7 The molding quality was poor, and the density dropped to 97.2%.

[0063] As demonstrated in Examples 1-3 and Comparative Examples 1-4, high-energy low-speed forming combined with high-energy high-speed remelting completely melts the original micron-sized ceramic particles, generating Ti(C,N) nanophases. By setting reasonable laser forming and remelting processes, the initially generated ceramic dendrites are refined through remelting, generating fine Ti(C,N) nanophases. This increases their uniform distribution and density in the titanium alloy matrix, improves interfacial bonding, reduces the probability of interfacial crack initiation, enhances the dispersion strengthening effect of the nano-reinforcing phase in the matrix, and improves the supersaturated solid solution of elements in the matrix, ultimately improving the forming quality and mechanical properties of the material.

[0064] This invention provides a method for preparing nano-reinforced titanium-based composite materials based on a high-energy, low-speed forming process combined with a high-energy, high-speed remelting process. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing nano-reinforced titanium-based composite materials based on a high-energy, low-speed forming combined with a high-energy, high-speed remelting process, characterized in that, Includes the following steps: (1) TiC ceramic powder and TiN ceramic powder are mixed by high-energy ball milling to obtain TiC-TiN mixed powder in which submicron TiC is coated on the surface of micron-sized TiN particles; (2) The TiC-TiN mixed powder from step (1) and the titanium alloy powder are ball-milled and mixed evenly under inert gas protection to obtain titanium-based composite powder; (3) Establish a three-dimensional solid geometric model of the part, slice the model into layers, plan the laser scanning path and set the forming and remelting process, discretize the three-dimensional solid into a series of two-dimensional data, save and import it into the laser powder bed melting forming equipment; (4) The laser powder bed melting and forming equipment melts and solidifies the titanium-based composite powder in step (2) layer by layer according to the data imported in step (3) and performs high-energy high-speed laser remelting to finally form the target three-dimensional solid part. In step (1), the TiC ceramic powder is a submicron-sized powder with a particle size distribution range of 0.1~0.6 μm; The TiN ceramic powder is a micron-sized powder with a particle size distribution range of 2~6 μm; In step (4), the laser powder bed melting forming equipment adopts a high-energy low-speed scanning process during the laser forming process, and then the solidified titanium-based composite material is remelted at high energy and high speed. In step (4), the laser power used for high-energy low-speed forming of laser powder bed melting is 250~300 W, the laser scanning speed is 500~700 mm / s, the scanning distance is 50 μm, and the powder thickness is 50 μm; In step (4), the high-energy high-speed remelting process uses a laser power of 250~300 W and a laser scanning speed of 1300~1500 mm / s.

2. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (1), the purity of the TiC ceramic powder is greater than 99.5%.

3. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (1), the purity of the TiN ceramic powder is greater than 99.5%.

4. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (1), the TiC ceramic powder and TiN ceramic powder are ball-milled and mixed in a single-tank planetary high-energy ball mill under inert gas protection. The ball-to-material ratio is 10:1, the high-energy ball milling speed is 225-275 rpm, and the ball milling time is 12-18 h. The TiC ceramic powder is coated on the surface of the TiN ceramic powder particles to prepare TiC-TiN mixed powder.

5. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (1), the mass ratio of TiC ceramic powder to TiN ceramic powder is 4:3 to 5:

3.

6. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (2), the TiC-TiN mixed powder accounts for 15~20 wt.% of the total mass of the titanium-based composite powder.

7. The method for preparing nano-reinforced titanium-based composite materials based on high-energy low-speed forming combined with high-energy high-speed remelting process according to claim 1, characterized in that, In step (2), the titanium alloy powder is a titanium-aluminum-zirconium-vanadium-molybdenum-niobium alloy, wherein the aluminum content is 6.5~7.0 wt.%, the zirconium content is 5.8~6.3 wt.%, the vanadium content is 2.0~2.2 wt.%, the molybdenum content is 2.0~2.3 wt.%, the niobium content is 0.5~0.8 wt.%, and the balance is titanium; the particle size distribution range of the titanium alloy powder is 21~57 μm.

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