A dual-structured titanium-based composite material based on additive manufacturing and method thereof

Abstract

The application discloses a kind of based on additive manufacturing double-structure titanium matrix composite and method thereof, specifically a kind of preparation method of double-structure titanium matrix composite for adjustable reinforcing phase content, mesh size, mesh structure area continuity, belongs to titanium matrix composite microstructure design field.Its preparation operation procedure includes: metal and reinforcing phase powder screening and pretreatment;Low-energy ball milling powder mixing;Printing pretreatment;Setting additive manufacturing printing parameter;Using double nozzle to carry out bulk printing according to different proportions simultaneously.The method makes mesh structure size, reinforcing phase content, mesh structure area continuity flexible and controllable, and has the characteristics of saving raw materials, simple operation, high dimensional accuracy, and has better more balanced mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microstructure design and preparation of titanium matrix composites, and specifically relates to a dual-structure titanium matrix composite based on direct energy deposition additive manufacturing and a method thereof. In the method, the size of the network structure, the content of the reinforcing phase, and the continuity of the network region are controllable. BACKGROUND

[0002] Titanium matrix composites are widely used in aerospace, vehicle engineering, and biomedical engineering due to their high specific strength, high specific modulus, good high-temperature performance, good high-temperature resistance, and good corrosion resistance. Additive manufacturing of titanium alloys, especially dual-phase titanium alloy TC4, has been widely studied and maturely applied in various fields. Due to the extremely fast cooling rate, additive manufacturing TC4 presents a needle-like alpha phase martensite structure, which results in high strength but low elongation, often less than 10%. For additive manufacturing TC4, higher strength and better strength-plasticity matching have always been the pursuit of researchers. Although the addition of reinforcing phases can greatly improve the strength of TC4, it can also cause severe plasticity reduction and even brittle fracture. To avoid this problem, the microstructure design of titanium matrix composites has become a widely studied hot issue. Among them, the traditional methods, including sintering and powder metallurgy, to prepare titanium matrix composites with network structure often have better strength-plasticity matching performance, which can greatly improve the strength while still maintaining certain plasticity. The introduction of network structure design into additive manufacturing of titanium matrix composites can achieve a large increase in strength, but due to the growth of vertical thick beta dendrites, the whiskers in the XOZ plane are arranged along the printing direction. Such whisker preferential growth can cause early fracture of the material and provide a growth aggregation route for crack propagation, making the material unable to obtain crack deflection and kinking. From the mechanical property results of additive manufacturing of network structure titanium matrix composites, the elongation is often decreased, and the performance is unstable. Therefore, the present application proposes a dual-structure titanium matrix composite, which makes the whiskers grow along the initial beta crystals, but the microstructure of the network structure region is discontinuously distributed, providing sufficient deflection and torsion space for crack propagation and growth, thereby achieving synergistic improvement of mechanical properties. SUMMARY

[0003] The present application solves the problems of high preparation cost, complex process, and high cost of subsequent processing of additive manufacturing of titanium matrix composites with network structure or dual structure, and proposes a dual-structure titanium matrix composite based on additive manufacturing and a method thereof. In the method, TiB wThe microstructure of the reinforced phase presents a reticular structure distribution, but the reticular region presents a discontinuous distribution, the method can make the content of the reinforced phase, the size of the reticular structure, and the continuity of the reticular structure region in the reticular structure be flexibly controllable, and the material design and preparation are facilitated.

[0004] The specific technical scheme adopted by the present application is as follows:

[0005] In a first aspect, the present application provides a preparation method of a double-structure titanium-based composite material based on additive manufacturing, which is specifically as follows:

[0006] S1: The Ti6Al4V metal powder and the TiB2 powder respectively subjected to vacuum drying treatment are mixed and subjected to low-energy ball milling, so as to realize the inlaying and adhering of the TiB2 powder on the Ti6Al4V metal powder under the premise of ensuring that the powder has good sphericity and integrity; the product after ball milling is subjected to vacuum drying treatment, so as to obtain a mixed powder;

[0007] S2: Based on an additive manufacturing equipment, the Ti6Al4V metal powder is placed into a first powder loading tank, and the mixed powder is placed into a second powder loading tank; a double nozzle is used to perform powder feeding according to a set powder feeding speed ratio, so as to complete printing and obtain a double-structure titanium-based composite material, and the distribution of the reinforced phase presents a reticular rule, but the reticular region presents a discontinuous distribution rule.

[0008] Preferably, in the step S1, the particle size distribution of the Ti6Al4V spherical metal particles is 65-150 μm, the Hall flow rate is 28.1 s / 50 g, the loose bulk density is 2.37 g / cm 3 , and the tap density is 2.75 g / cm 3 ; the TiB2 particles are reactants for generating titanium boride whisker reinforced phase in situ, and the particle size distribution is 1-3 μm.

[0009] Preferably, the vacuum drying treatment operation is as follows: the material is placed in a glass dish and is kept at 120℃ in a vacuum environment for one hour.

[0010] Preferably, the ball milling process of the step S1 is specifically as follows:

[0011] The Ti6Al4V metal powder 59.49 g (or 58.98 g) and the TiB2 powder 0.51 g (or 1.02 g) after drying pretreatment are weighed respectively, 300 g of ball milling beads with particle sizes of 6 mm and 10 mm are selected, and the ball milling beads and the powder are subjected to ball milling in a ceramic ball milling tank; the ball milling speed is 200-225.5 revolutions per minute, the ball-to-material ratio is 5:1, the ball milling time is 6-8 h, and the ball milling atmosphere is an argon atmosphere; after the ball milling, the reinforced phase TiB w with a mass fraction of 0.5% (or 1%) is generated in situ.

[0012] As preferred, the additive manufacturing equipment model is BLT-C400, and the pre-treatment operation before use is as follows:

[0013] Argon is flushed into the additive manufacturing equipment for gas washing operation, so as to keep the oxygen content in the cabin below 200 ppm, open the pressure maintaining, and maintain the cabin pressure constant at 0.6 MPa.

[0014] As preferred, the printing parameter setting operation of the additive manufacturing equipment before use is specifically as follows:

[0015] A printing block model is established by using Magic three-dimensional modeling software; printing parameters of the printing block model are set by using BLT-BP software, a scanning path.nc file is generated and stored in the additive manufacturing equipment; wherein, the printing idle speed is set to 1000 mm / min, the printing mode is platform mode, the scanning sequence is inner filling plus outer circle, the layer thickness is 0.4 mm, the outer circle number is 0, the spot diameter is 1 mm, the inner filling is selected and applied, the filling mode is continuous scanning mode, the path distance is 1 mm, the rotation start angle is 0°, the rotation increase angle is 90°, the laser power is 750-800 W, the scanning rate is 700-800 mm / min, the powder carrying gas speed is set to 6 L / min, the dust removal fan speed is 2 gears, and the lens gas is 22 L / min.

[0016] As preferred, in the step S2, the double spray heads send powder according to the set proportion, and the operation of preparing the double-structure titanium-based composite material is specifically as follows:

[0017] S21: the TC4 metal powder is put into the first powder carrying tank, and the mixed powder is put into the second powder carrying tank;

[0018] S22: the rotation speed of the first powder feeder is set to 1%, the rotation speed of the second powder feeder is set to 1%, and then the printing is started, as shown in the printing schematic diagram; Figure 1

[0019] S23: the printing operation is completed, and the TC4 / TiB w composite material is obtained; in the double-structure titanium-based composite material, the reinforcing phase distribution presents a net structure rule, but the net area presents a discontinuous distribution rule, and the structure parameters such as the net size and the net area continuity are affected by the proportion relationship of the two powders during printing.

[0020] In a second aspect, the present application provides a double-structure titanium-based composite material prepared by using the preparation method of any one of the first aspect.

[0021] Compared with the preparation methods of the net titanium-based composite material or other structure metal-based composite material in the prior art, the present application has the following advantages: ​

[0022] The present application can be used for the design and preparation of metal matrix composites with double structure, is an important research direction in the field of microstructure design of metal matrix composites, has reference significance for the application of additive manufacturing and the preparation of metal matrix composites. It has high academic value and great industrial application prospect. Compared with other preparation methods of metal matrix composites with net or semi-continuous net structure, such as ion spark sintering, cumulative roll bonding, diffusion welding, etc., this method has the following characteristics:

[0023] 1. The preparation process is clear, and the requirement for external environment is low. In the ball milling and additive manufacturing process, the metal powder and block are in a closed environment and are protected by argon gas, which is not sensitive to external environmental factors.

[0024] 2. The process is mature and easy to control. The ball milling process in the preparation process is mature, the principle is easy to understand, the variables are few, and it is easy to control. The additive manufacturing process and equipment technology are mature and stable, and the preparation process is implemented through software, which is simple to operate.

[0025] 3. The preparation process is simple, which saves time and raw materials. The additive manufacturing preparation method can realize near-net shaping of parts, avoid subsequent process processing and post-processing, and realize the saving of raw materials and time cost.

[0026] 4. Strong design flexibility, many design variables. This method can flexibly design and adjust the design variables such as reinforcement phase content, net structure size, and net structure region continuity, without increasing the preparation process and time.

[0027] 5. Wide applicability. This method is suitable for various alloy systems, and can use different types of metal powders to prepare semi-continuous structures, or add other types of reinforcement phase particles to prepare different types of metal matrix composites.

[0028] The present application can be used for the preparation of TC4-TiB w double structure composite. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a printing principle diagram of semi-continuous net structure titanium matrix composite.

[0030] Figure 2 is a scanning electron microscope photo of TC4 powder (a), TC4 and TiB2 mixed powder after ball milling (b). Figure 2 Figure 2

[0031] Figure 3 is a photo of the composite block prepared in Example 1.

[0032] Figure 4 ​​The scanning electron microscope photo of the bicontinuous structure titanium matrix composite prepared in Example One, wherein the proportion of TC4 powder is 75% and the proportion of TC4-TiB2 (0.5%) mixed powder is 25% in the preparation process.

[0033] Figure 5 The tensile engineering stress-strain curve of three bicontinuous structure titanium matrix composites in Example One to Example Three. The green line is the tensile stress-strain curve of the mechanical properties of the ordinary TC4 alloy prepared by direct laser stereoscopic forming additive manufacturing; the black line is the tensile stress-strain curve of the mechanical properties of the bicontinuous structure titanium matrix composite prepared by direct laser stereoscopic forming in Example One; the red line is the tensile stress-strain curve of the mechanical properties of the bicontinuous structure titanium matrix composite prepared by direct laser stereoscopic forming in Example Three; and the blue line is the tensile stress-strain curve of the mechanical properties of the bicontinuous structure titanium matrix composite prepared by direct laser stereoscopic forming in Example Four.

[0034] Figure 6 The scanning electron microscope photo of the bicontinuous structure titanium matrix composite in Example Two, wherein the white line encircles the reticular structure region, and the red line encircles the non-reticular structure region, wherein the reinforcing phase in the non-reticular structure region is in a uniform distribution state.

[0035] Figure 7 The scanning electron microscope photo of the bicontinuous structure titanium matrix composite in Example Three, wherein the white line encircles the reticular structure region, and the red line encircles the non-reticular structure region, wherein the reinforcing phase in the non-reticular structure region is in a uniform distribution state. DETAILED DESCRIPTION

[0036] The present application will be further described and illustrated in the following with reference to the drawings and specific embodiments. The technical features of each embodiment in the present application can be combined accordingly without conflict.

[0037] The present application provides a preparation method of a bicontinuous structure titanium matrix composite (i.e. TC4-TiB w The preparation method of the present application mainly comprises the following steps:

[0038] I. Screening and Pretreatment of Metal and Reinforcing Phase Powders. Laser additive manufacturing methods place high demands on the flowability and sphericity of metal powders. In this invention, spherical Ti6Al4V (TC4) metal particles with a particle size distribution of 65-150 μm (D10=58.84μm, D50=84.61μm, D90=117.5μm), a Hall flow rate of 28.1 s / 50g, and a loose packing density of 2.37 g / cm³ are preferably selected. 3 The tap density is 2.75 g / cm³. 3 TiB2 particles with a particle size distribution of 1-3 μm were selected as in-situ generated titanium boride whiskers (TiB2). w The reactants for the reinforcing phase were prepared by placing TC4 metal powder and TiB2 powder separately into glass dishes and then placing them in a vacuum chamber for incubation. The powders were then dried and pretreated by maintaining the temperature at 120°C for one hour under vacuum.

[0039] Here, TC4 powder with a particle size of 65-150 μm and D50 = 84.61 μm is preferably selected. TiB2 powder with a particle size of 1-3 μm is also preferred. During additive manufacturing, titanium boride whiskers are generated in situ, and the whisker distribution exhibits a network structure. However, since TC4 powder and mixed powder are fed together for printing, the regions with the network structure exhibit a discontinuous microstructure. Regions with and without the network structure are interconnected. The network size and the continuity of the network structure regions are affected by the content of the reinforcing phase and the proportion of mixed powder.

[0040] II. Low-energy ball milling and powder mixing. Weigh a certain proportion of TC4 metal powder ( Figure 2 (a) The TiB2 powder is mixed with TiB2 powder and then ball-milled at low energy. This achieves a relatively uniform embedding and adhesion of TiB2 particles onto TC4 particles while ensuring good sphericity and integrity of the powder. In this invention, preferably 59.49 g (or 58.98 g) of TC4 powder and 0.51 g (or 1.02 g) of TiB2 are weighed, and 300 g of 6 mm and 10 mm ball milling beads are selected and ball-milled in a ceramic ball mill jar. The ball milling speed is 200-225.5 rpm, the ball-to-powder ratio is 5:1, the ball milling time is 6-8 h, and the ball milling atmosphere is argon. This method can achieve a good and uniform embedding and adhesion effect while ensuring good sphericity and integrity. Figure 2 (b)).

[0041] Here, 59.49 g (or 58.98 g) of TC4 powder and 0.51 g (or 1.02 g) of TiB2 are preferably ball-milled to induce in-situ formation of the reinforcing phase TiB2. wThe mass fraction is 0.5% (or 1%). Preferably, the ball milling parameters are selected as 200-225.5 revolutions per minute, a ball-to-material ratio of 5:1, a ball milling time of 6-8 hours, an argon environment, and a ball size of 6 mm and 10 mm mixed. This is because, through 18 groups of orthogonal ball milling experiments including ball milling speed, time, and ball-to-material ratio parameters, and scanning electron microscope observation of the powder particles after ball milling of each group, it is found that the above parameters are the most suitable ball milling parameters, which can form a good and uniform inlaying combination effect of TC4 powder and TiB2 powder under the premise of ensuring the sphericity and integrity.

[0042] III. Printing pretreatment. The mixed powder obtained in step II is placed in a glass dish and placed in a vacuum box for vacuum heat preservation. In actual application, it is preferred to adopt vacuum environment, heat preservation at 120°C for one hour to ensure powder drying; at the same time, the additive manufacturing equipment BLT-C400 used is gas washed, filled with argon, and the oxygen content in the cabin is reduced to below 200 ppm, the pressure is maintained, and the gas pressure in the cabin is kept constant at 0.6 MPa.

[0043] IV. Setting additive manufacturing printing parameters. The Magic three-dimensional modeling software is used to establish a printing block model. In actual application, the BLT-BP software can be used to set the printing parameters of the model, generate a scanning path.nc file and store it in the BLT-C400. Among them, the printing idle speed is set to 1000 mm / min, the printing mode is platform mode, the scanning sequence is inner filling plus outer circle, the layer thickness is 0.4 mm, the outer circle number is 0, the spot diameter is 1 mm, the inner filling is selected, the filling mode is continuous scanning mode, the path spacing is 1 mm, the rotation start angle is 0°, the rotation increase angle is 90°, the laser power is 750-800 W, the scanning speed is 700-800 mm / min, the powder feeding gas speed is set to 6 L / min, the dust removal fan speed is 2 gears, and the lens gas is 22 L / min.

[0044] Through additive manufacturing single-pass and double-pass experiments including laser power and scanning speed parameters, the best path spacing and layer thickness under each group of parameters are obtained. Through ten groups of orthogonal experiments including printing parameters such as laser power, scanning speed, and powder feeding speed, the above parameters are obtained as the best printing parameters, the block density is 99.97%, and the maximum pore size is 70 microns.

[0045] V. Printing the block by using double powder tanks according to the set ratio to send powder at the same time to obtain a double-structure titanium-based composite material.

[0046] Among them, the operation of sending powder at the same time by double powder tanks according to the set ratio is as follows:

[0047] The TC4 metal powder is placed in the first powder tank, the mixed powder obtained in step three is placed in the second powder tank, the first powder feeder is set to rotate at a speed of 1%, the second powder feeder is set to rotate at a speed of 1%, and printing is started. After the printing operation is completed, a TC4 / TiB w The double-structure titanium-based composite material, wherein the reinforcing phase is distributed in a net-like manner, but the net-like region is discontinuous, and the degree of continuity is affected by the powder feeding ratio.

[0048] Example One

[0049] In this embodiment, a double-structure titanium-based composite material is prepared, and the specific preparation method is as follows:

[0050] I. Select Ti6Al4V (TC4) spherical metal particles with a particle size distribution of 65-150 μm (D10 = 58.84 μm, D50 = 84.61 μm, D90 = 117.5 μm), Hall flow rate is 28.1 s / 50 g, loose bulk density is 2.37 g / cm 3 , tap density is 2.75 g / cm 3 , and select 1-3 μm particle size distribution TiB2 particles as the reactant of the in-situ generated titanium boride whisker (TiB w ) reinforcing phase. The TC4 metal powder and TiB2 powder are placed in glass dishes and placed in a vacuum box for heat preservation. In a vacuum environment, heat preservation at 120°C for one hour, powder drying pretreatment.

[0051] II. Weigh 59.49 g of TC4 powder and 0.51 g of TiB2, select 300 g of ball milling beads with particle sizes of 6 mm and 10 mm, and ball mill in a ceramic ball milling jar. Set the ball milling speed to 225.5 revolutions per minute, the ball-to-material ratio to 5:1, the ball milling time to 8 h, and the ball milling atmosphere to argon atmosphere.

[0052] III. The mixed powder obtained in step II is placed in a glass dish and placed in a vacuum box for vacuum heat preservation. In a vacuum environment, heat preservation at 120°C for one hour to ensure powder drying. The additive manufacturing equipment BLT-C400 used is gas washed, filled with argon, and the oxygen content in the cabin is maintained below 200 ppm. The pressure is maintained, and the cabin pressure is kept constant at 0.6 MPa.

[0053] IV. Using Magic 3D modeling software, a 55mm × 26mm × 15mm cuboid model was created. The BLT-BP software was used to set the printing parameters for the model, generating a scan path .nc file and saving it to the BLT-C400. The settings included: printing idle speed of 1000mm / min, printing mode of platform mode, scanning sequence of inner fill plus outer ring, layer thickness of 0.4mm, number of outer rings of 0, spot diameter of 1mm, selection of inner fill, continuous scan mode, path spacing of 1mm, rotation start angle of 0°, rotation increase angle of 90°, laser power of 750W, scanning rate of 700mm / min, toner gas speed of 6L / min, dust removal fan speed of level 2, and lens gas speed of 22L / min.

[0054] 5. Place the TC4 metal powder obtained in step one into the first toner container, and the mixed powder obtained in step three into the second toner container. Set the rotation speed of the first toner feeder to 1.5% and the rotation speed of the second toner feeder to 0.5%, and begin printing. After completing the printing operation, you will obtain TC4 / TiB. w Dual-structure composite materials (such as) Figure 3 and 4 (As shown). Figure 3 Photographs of the prepared bulk materials. Figure 4 The image shows a SEM photograph of the material in this embodiment. As can be seen from the image, due to the low content of the reinforcing phase, the network structure and dual structure features are not obvious, and the whiskers generally exhibit a uniform distribution.

[0055] This embodiment utilizes a BLT-C400 additive manufacturing equipment with two powder feeders simultaneously feeding powder at a set rate to prepare a composite material with a dual continuous structure. In this embodiment, a tensile stress-strain curve was obtained through a tensile test. Figure 5 (Black). It can be seen that the modulus and strength of the dual-structure titanium-based composite material are improved to a certain extent, with the strength reaching 1220 MPa and the elongation reaching 8.5%. This means that the current dual-structure design is beneficial to the improvement of the material's strength and modulus, and the toughness is not significantly reduced.

[0056] Example 2

[0057] This embodiment prepared a dual-structure titanium-based composite material. The specific preparation method was basically the same as in Example 1, except that in step five, the rotation speed of the first powder feeder was set to 1%, and the rotation speed of the second powder feeder was also set to 1%. Finally, printing was completed, and a sample was obtained.

[0058] This embodiment describes the preparation of TiB by controlling the powder feeding rate of the two powder feeders of the BLT-C400 additive manufacturing equipment while simultaneously feeding powder for printing. wThe dual-structure titanium-based composite material has a network distribution of the reinforcing phase, but the network region has a discontinuous distribution. A scanning electron microscope image of the dual-structure titanium-based composite material is shown in FIG. 6, where the region circled by the white line is the network region, and the region circled by the red line is the non-network region. The material is composed of the network structure region and the non-network structure region, and the reinforcing phase is uniformly distributed in the non-network region. Figure 6 The tensile curve result of this embodiment is shown by the red line in FIG. 7. As can be seen from the comparison, the strength of the material is 1071 MPa, and the elongation is 11%. The structure design greatly improves the strength and modulus of the material and slightly improves the toughness, achieving the effect of simultaneously strengthening and toughening. Figure 5 The tensile curve result of this embodiment is shown by the red line in FIG. 7. As can be seen from the comparison, the strength of the material is 1071 MPa, and the elongation is 11%. The structure design greatly improves the strength and modulus of the material and slightly improves the toughness, achieving the effect of simultaneously strengthening and toughening.

[0059] Example Three

[0060] In this embodiment, a dual-structure titanium-based composite material is prepared, and the preparation method is basically the same as that in Example 1, except that: in step two, 58.98 g of TC4 powder and 1.02 g of TiB2 are weighed and mixed to prepare a mixed powder. It is expected that the TiB2 reinforcing phase accounts for 1% in the prepared material. In step five, the rotation speed of the first powder feeder is set to 1%, and the rotation speed of the second powder feeder is set to 1%. Finally, the printing is completed, and a sample is obtained.

[0061] In this embodiment, a TiB2 reinforced titanium-based composite material is prepared by controlling the powder feeding rates of the two powder feeders of the additive manufacturing equipment BLT-C400 and printing at the same time. w The dual-structure titanium-based composite material has a network distribution of the reinforcing phase, but the network region has a discontinuous distribution. A scanning electron microscope image of the dual-structure titanium-based composite material is shown in FIG. 6, where the region circled by the white line is the network region, and the region circled by the red line is the non-network region. The material is composed of the network structure region and the non-network structure region, and the reinforcing phase is uniformly distributed in the non-network region. Figure 7 The tensile curve result of this embodiment is shown by the red line in FIG. 7. As can be seen from the comparison, the strength of the material is 1071 MPa, and the elongation is 11%. The structure design greatly improves the strength and modulus of the material and slightly improves the toughness, achieving the effect of simultaneously strengthening and toughening. Figure 5 The tensile curve result of this embodiment is shown by the red line in FIG. 7. As can be seen from the comparison, the strength of the material is 1071 MPa, and the elongation is 11%. The structure design greatly improves the strength and modulus of the material and slightly improves the toughness, achieving the effect of simultaneously strengthening and toughening.

[0062] The above-described embodiments are only a preferred scheme of the present application, and are not intended to limit the present application. Those skilled in the related art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical scheme obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A method for preparing a dual-structure titanium-based composite material based on additive manufacturing, characterized in that, Specifically as follows: S1: Ti6Al4V metal powder and TiB2 powder, which have been vacuum dried respectively, are mixed and subjected to low-energy ball milling to achieve the embedding and adhesion of TiB2 powder on Ti6Al4V metal powder while ensuring that the powder has good sphericity and integrity; the product after ball milling is vacuum dried to obtain mixed powder. S2: Based on additive manufacturing equipment, Ti6Al4V metal powder is placed into the first powder carrier tank, and the mixed powder is placed into the second powder carrier tank; using dual nozzles to feed powder and perform block printing at the set powder feeding speed ratio, a dual-structure titanium-based composite material with different continuity of mesh structure regions is obtained. The specific steps for setting the printing parameters of the additive manufacturing equipment before use are as follows: Using Magic 3D modeling software, a printable block model was created. Using BLT-BP software, printing parameters were set for the printable block model, generating a scan path .nc file which was then stored in the additive manufacturing equipment. Specifically, the print idle speed was set to 1000 mm / min, the printing mode to platform mode, the scanning sequence to inner fill with an outer ring, the layer thickness to 0.4 mm, the number of outer rings to 0, the spot diameter to 1 mm, the inner fill option to be selected, the fill mode to be continuous scanning mode, the path spacing to 1 mm, the rotation start angle to 0°, the rotation increase angle to 90°, the laser power to 750-800 W, the scanning rate to 700-800 mm / min, the powder carrier gas speed to 6 L / min, the dust removal fan speed to level 2, and the lens gas speed to 22 L / min. In step S2, after printing begins, the rotation speed of the first toner feeder connected to the first toner tank is set to 1%, and the rotation speed of the second toner feeder connected to the second toner tank is set to 1%, so that the two toner tanks simultaneously feed toner to the dual printheads for printing until printing is completed.

2. The method for preparing a dual-structure titanium-based composite material based on additive manufacturing according to claim 1, characterized in that, In step S1, the Ti6Al4V spherical metal particles have a particle size distribution of 75-160 μm, a Hall flow rate of 28.1 s / 50 g, and a loose packing density of 2.37 g / cm³. 3 The tap density is 2.75 g / cm³. 3 The particle size distribution of TiB2 particles is 1-3 μm.

3. The method for preparing a dual-structure titanium-based composite material based on additive manufacturing according to claim 1, characterized in that, The vacuum drying process is as follows: the material is placed in a glass dish and kept at 120°C in a vacuum environment for one hour.

4. The method for preparing a dual-structure titanium-based composite material based on additive manufacturing according to claim 1, characterized in that, The ball milling process in step S1 is as follows: Ti6Al4V metal powder and TiB2 powder, after drying and pretreatment, were weighed separately. 300 g of grinding beads with particle sizes of 6 mm and 10 mm were selected and ball-milled together in a ceramic ball mill jar. The ball milling speed was 200-225.5 rpm, the ball-to-powder ratio was 5:1, the ball milling time was 6-8 h, and the ball milling atmosphere was argon. After ball milling, the reinforcing phase TiB2 was generated in situ. w ; During the ball milling process, 59.49 g of Ti6Al4V metal powder and 0.51 g of TiB2 powder were taken. After ball milling, the reinforcing phase TiB2 was generated in situ. w The mass fraction is 0.5%; or during ball milling, 58.98 g of Ti6Al4V metal powder and 1.02 g of TiB2 powder are taken, and the reinforcing phase TiB2 is generated in situ after ball milling. w The mass fraction is 1%.

5. The method for preparing a dual-structure titanium-based composite material based on additive manufacturing according to claim 1, characterized in that, The additive manufacturing equipment is model BLT-C400. The pretreatment procedures before use are as follows: Argon gas is injected into the additive manufacturing equipment for gas scrubbing to keep the oxygen content in the cabin below 200 ppm. The pressure holding is then activated to maintain a constant cabin pressure of 0.6 MPa.

6. A dual-structure titanium-based composite material obtained by any one of the preparation methods described in claims 1 to 5.

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