Layered titanium matrix composite based on direct energy deposition additive manufacturing and method thereof

Abstract

The application discloses a layered titanium-based composite material based on direct energy deposition additive manufacturing and a method thereof, and particularly relates to a preparation method of a layered composite material which can be used for controlling or gradient distribution of layer thickness, layer stacking sequence and reinforcing phase content, and belongs to the field of layered titanium-based composite material preparation. The preparation operation process comprises the following steps: metal and reinforcing phase powder screening and pretreatment, low-energy ball milling powder mixing, printing pretreatment, setting additive manufacturing printing parameters, and using double-nozzle alternate powder feeding or proportional powder feeding to perform block printing. The method makes the layered thickness, layer stacking sequence and reinforcing phase content flexible and controllable, and has the characteristics of good interface bonding, simple operation, high size precision and the like.

Description

Technical Field

[0001] This invention belongs to the field of layered titanium-based composite material preparation, specifically a layered titanium-based composite material and method based on direct energy deposition additive manufacturing. In this method, the layer thickness, layer thickness ratio, and reinforcing phase content of the layered structure are controllable. Background Technology

[0002] Titanium matrix composites, as high-performance lightweight metal alloys, possess high specific strength and specific modulus at room temperature, second only to carbon fiber composites, but with a much wider operating temperature range and greater structural stability. Adding or in-situ reacting reinforcing phases to generate them has been widely recognized as a reliable method to improve the strength and modulus of titanium matrix composites. However, the addition of reinforcing phases often leads to a significant decrease in toughness. Therefore, quasi-continuous distribution of reinforcing phases and various structural designs for metal matrix composites have been proposed. Among these, network-distributed titanium matrix composites have successfully improved the material's strength and reduced the reduction in toughness, but still cannot avoid the problem of easy damage caused by reinforcing phase clusters. Layered metal matrix composite designs often allow the overall strength and modulus of the composite to conform to the mixing law of the two layers, while significantly improving toughness. However, the formation of brittle intermetallic compound phases at the interface between different materials, and the thermal stress caused by the different thermal expansion coefficients of the two layers, significantly affect the interfacial bonding and limit the development and application of layered metal matrix composites. A laser direct energy deposition additive manufacturing method is proposed to prepare a secondary structure titanium-based composite material with a reinforcing phase exhibiting a combination of network and layered structures. This method greatly facilitates the design and preparation of layered structures, reduces manufacturing costs and difficulties, and effectively avoids problems such as weak interfacial bonding and thermal stress, thus meeting the needs of scientific research and engineering applications. Summary of the Invention

[0003] This invention addresses the problems of high cost, complex process, and poor interfacial bonding in the fabrication of layered structures in titanium-based composites. It proposes a layered titanium-based composite material and its method based on direct energy deposition additive manufacturing. TiB w The reinforcing phase exhibits a network-layered secondary structure distribution. This method allows for flexible control over the thickness of a single layer, the ratio of the thicknesses of two layers, the layup sequence, and the content of the reinforcing phase in the layered structure, facilitating the design and preparation of materials.

[0004] The specific technical solution adopted in this invention is as follows:

[0005] In a first aspect, the present invention provides a method for preparing a layered titanium-based composite material based on direct energy deposition additive manufacturing, as detailed below:

[0006] 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.

[0007] S2: Using additive manufacturing equipment, Ti6Al4V metal powder is placed into a first powder carrier tank, and the mixed powder is placed into a second powder carrier tank; block printing is performed by alternately feeding powder with dual nozzles or feeding powder in proportion to obtain a layered titanium-based composite material.

[0008] Preferably, in step S1, the Ti6Al4V spherical metal particles have a particle size distribution of 65-150 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 TiB2 particles, used as reactants for the in-situ generation of titanium boride whisker reinforcing phases, have a particle size distribution of 1-3 μm.

[0009] Preferably, the vacuum drying process is performed as follows: the material is placed in a glass dish and kept at a vacuum temperature of 120°C for one hour.

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

[0011] 59.49 g of dried and pretreated Ti6Al4V metal powder and 0.51 g of TiB2 powder were weighed out, and 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 The mass fraction is 0.5%.

[0012] Preferably, the additive manufacturing equipment is model BLT-C400, and the pretreatment procedures before use are as follows:

[0013] Argon gas is injected into the equipment for gas purging to keep the oxygen content in the cabin below 200 ppm. Pressure holding is then activated to maintain a constant cabin pressure of 0.6 MPa.

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

[0015] Using Magic 3D modeling software, a printable block model was created. BLT-BP software was used to set the printing parameters for the 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 to be applied, the fill mode to 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 2, and the lens gas speed to 20 L / min.

[0016] Preferably, in step S2, the alternating powder feeding operation of the dual nozzles is as follows:

[0017] S21: Set the rotation speed of the first powder feeder connected to the first powder tank to 2%, and the rotation speed of the second powder feeder connected to the second powder tank to 0, and then start printing one layer of material;

[0018] S22: Set the rotation speed of the first powder feeder to 0 and the rotation speed of the second powder feeder to 2%, then start printing one layer of material;

[0019] S23: Then repeat steps S21 to S22 in sequence until the printing operation is completed, and obtain the layered titanium matrix composite material TC4-TC4 / TiB. w ;TC4-TC4 / TiB w In layers containing reinforcing phases, the reinforcing phases exhibit a network distribution.

[0020] Preferably, in step S2, the powder feeding operation according to the ratio is as follows:

[0021] During the first layer printing, the rotational speed of the first powder feeder connected to the first powder container is set to 2%, and the rotational speed of the second powder feeder connected to the second powder container is set to 0%. During the second layer printing, the rotational speed of the first powder feeder is 1.9%, and the rotational speed of the second powder feeder is 0.1%. Following this pattern, after each layer is printed, the rotational speed of the first powder feeder is reduced while the rotational speed of the second powder feeder is increased, while maintaining their sum at 2%, until printing is complete, resulting in a layered titanium-based composite material. In the layered titanium-based composite material, TiB... w The enhanced phase exhibits a gradient layered distribution characteristic.

[0022] In a second aspect, the present invention provides a layered titanium-based composite material obtained by any of the preparation methods described in the first aspect.

[0023] Compared with current methods for preparing layered titanium-based composite materials or other layered metal-based composite materials, this invention has the following advantages:

[0024] This invention can be used for the design and preparation of layered metal matrix composites, representing an important research direction in the field of microstructure design for metal matrix composites. It offers valuable insights for additive manufacturing applications and the preparation of metal matrix composites. It possesses high academic value and significant industrial application prospects. Compared to other methods for preparing layered metal matrix composites, such as ion-electrospray sintering, cumulative roll bonding, and diffusion welding, this method has the following characteristics:

[0025] 1. The preparation process is clear and has low requirements for the external environment. In the ball milling and additive manufacturing processes, both the metal powder and the bulk material are in a closed environment and are protected by argon gas, making them insensitive to external environmental factors.

[0026] 2. Mature and easy-to-control processes. The ball milling process in the preparation flow is mature, its principle is easy to understand, has few variables, and is easy to control. The additive manufacturing process and equipment technology are mature and stable, and the preparation flow is implemented through software, making operation simple.

[0027] 3. The preparation process is simple, saving time and raw materials. Traditional methods for preparing layered structures require preparing a block, cutting it into layered materials, and then bonding them together. This method achieves this in one step, generating a layered structure in situ, with the same time and raw material requirements as additive manufacturing for isotropic titanium alloys.

[0028] 3. The layered interface has a good and stable bond. When printing each layer in additive manufacturing, the previous layer needs to be remelted and solidified, making the two layers more tightly bonded than in traditional mechanical methods, without obvious layered boundaries.

[0029] 4. High design flexibility and numerous design variables. This method allows for relatively flexible design and adjustment of design variables such as layer thickness, layer-to-layer thickness ratio, layup sequence, and reinforcing phase content, without increasing the preparation process or time.

[0030] 5. Wide applicability. This method is applicable to various alloy systems. It can be used to prepare layered structures using different types of metal powders, and other types of reinforcing phase particles can be added to prepare different kinds of metal matrix composites.

[0031] This invention is used to prepare TC4 / TC4-TiB w A layered composite material, wherein the reinforcing phase is distributed in a network pattern within the layers containing the reinforcing phase. Attached Figure Description

[0032] Figure 1 TC4 powder ( Figure 1 (a)), a mixture of TC4 and TiB2 after ball milling ( Figure 1 (b) Scanning electron microscope image.

[0033] Figure 2 Mechanical properties of TC4 with different mass fractions of TiB in additive manufacturing w Comparison of mechanical properties of reinforcing phases with a network distribution. The blue line represents the tensile mechanical properties of TC4; the yellow line represents TC4-0.1% TiB. w Tensile mechanical properties of composite materials; red line represents TC4-0.5% TiB w Tensile mechanical properties of composite materials; green line represents TC4-1% TiB w Tensile mechanical properties of composite materials; purple line represents TC4-2% TiB w Tensile mechanical properties of composite materials.

[0034] Figure 3 and Figure 4 The TiB2 powder prepared by additive manufacturing from the ball-milled mixture of TC4 and TiB2 in step two of Example 1 is a product of this process. w Scanning electron microscope (SEM) images of bulk titanium-based composite materials with a network-like distribution of reinforcing phases. Figure 3 For low magnification, Figure 4 It is a high multiple.

[0035] Figure 5 For the preparation of TC4-TC4 / TiB w Layered composite material block sample.

[0036] Figure 6 and Figure 7 In the layered composite material, the TC4 layer contains uniformly distributed TiB. w Scanning electron microscope images. Among them... Figure 6 For low magnification, Figure 7 It is a high multiple.

[0037] Figure 8 TC4 / TC4-TiB w In layered composite materials, TC4-TiB w Scanning electron microscope image of composite material layers.

[0038] Figure 9 TC4 / TC4-TiB w Scanning electron microscope image of the interface between two layers in a layered composite material.

[0039] Figure 10 TC4 / TC4-TiB prepared in Examples 1 to 3 wComparison of tensile test curves between layered titanium matrix composites and TC4 material. The blue line represents the tensile mechanical properties of TC4; the red line represents the tensile mechanical properties of the layered titanium matrix composite in Example 1; the purple line represents the tensile mechanical properties of the layered titanium matrix composite in Example 2; and the black line represents the tensile mechanical properties of the layered titanium matrix composite in Example 3.

[0040] Figure 11 TC4 / TC4-TiB prepared in Example 1 w Layered titanium-based composite material, (a) and (b) are two scanning electron microscope images of the side of the polished tensile sample after it was broken.

[0041] Figure 12 A side mirror photograph of a TC4 polished and stretched sample after it breaks ( Figure 12 (a) and TC4 / TC4-TiB prepared in Example 1 w A side optical microscope image of a polished tensile specimen of a layered titanium-based composite material after fracture. Figure 12 (b)).

[0042] Figure 13 This is a microstructure diagram of the first 8 layers of the material obtained in Example 4;

[0043] Figure 14 This is a microstructure diagram of layers 9 to 16 of the material obtained in Example 4;

[0044] Figure 15 This is a microstructure diagram of layers 17 to 24 of the material obtained in Example 4;

[0045] Figure 16 This is a microstructure diagram of layers 25 to 32 of the material obtained in Example 4;

[0046] Figure 17 This is a microstructure diagram of layers 33 to 38 of the material obtained in Example 4. Detailed Implementation

[0047] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0048] This invention provides a method for preparing layered titanium-based composite materials based on direct energy deposition additive manufacturing, which specifically includes the following steps:

[0049] 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 = 58.84 μm, D50 = 84.61 μm, D90 = 117.5 μm), a Hall flow rate of 28.1 s / 50 g, 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 pre-treated by drying at 120°C for one hour under vacuum.

[0050] Here, TC4 powder with a particle size of 65-150 μm and D50 of 84.61 μm is preferably selected. TiB2 powder with a particle size of 1-3 μm is also preferred. The network structure generated by additive manufacturing roughly exhibits an equiaxed hexagonal network morphology in the plane perpendicular to the deposition direction (i.e., in the XOY plane). Figure 3 and Figure 4 The size is approximately 10-30 μm; in the plane parallel to the deposition direction (i.e., in the XOZ plane), it exhibits an unequal-axis hexagonal network pattern, with a width of approximately 10-30 μm and a length of approximately 100-150 μm.

[0051] II. Low-energy ball milling and powder mixing. Weigh a certain proportion of TC4 metal powder ( Figure 1 a) The TiB2 particles are mixed with TiB2 powder and then ball-milled at low energy levels. 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 59.49g of TC4 powder and 0.51g of TiB2 are weighed, and 300g of ball milling beads with particle sizes of 6mm and 10mm 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 hours, 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 1 b).

[0052] Here, 59.49g of TC4 powder and 0.51g of TiB2 are preferably selected for ball milling to induce in-situ formation of the reinforcing phase TiB2. w The mass fraction is 0.5%. After processing the reinforcing phase TiB... w Network TC4-TiB with mass fractions of 0%, 0.1%, 0.5%, 1%, and 2% wAfter preparation and performance testing of composite additive manufacturing methods, TiB was found to be... w The composite material achieves optimal performance at a mass fraction of 0.5%. (TC4 and TC4-TiB at various mass fractions) w A comparison of the tensile mechanical properties of composite materials can be found in Figure 2 .from Figure 2 As can be seen from the data, after the addition of the reinforcing phase, TC4-TiB w The strength of all composite materials was improved, including TC4-0.1%TiB. w TC4-0.5%TiB w TC4-1%TiB w TC4-2%TiB w The strengths were 1130 MPa, 1250 MPa, 1181 MPa, and 1200 MPa, respectively. However, the elongation of the composites was reduced to varying degrees after the addition of the reinforcing phase, especially in TC4-0.1%TiB. w TC4-0.5%TiB w TC4-1%TiB w TC4-2%TiB w The elongation rates were 7%, 10%, 7%, and 4%, respectively. The preferred ball milling parameters were 200-225.5 revolutions per minute, a ball-to-powder ratio of 5:1, a milling time of 6-8 hours, an argon atmosphere, and a mixture of 6mm and 10mm ball sizes. This was because, after conducting 18 orthogonal ball milling experiments, including parameters related to milling speed, time, and ball-to-powder ratio, and observing the powder particles after milling using scanning electron microscopy, it was found that the powder had different optimal ball milling parameters for different TiB2 contents. The parameters mentioned above are the optimal ball milling parameters when the reinforcing phase content is 0.5%, which can achieve a good and uniform interlocking effect between TC4 powder and TiB2 powder while ensuring sphericity and integrity.

[0053] III. Printing Pretreatment. The mixed powder obtained in step II is placed in a glass dish and then placed in a vacuum chamber for vacuum insulation. Under vacuum conditions, it is kept at 120°C for one hour to ensure the powder is dry. The BLT-C400 additive manufacturing equipment used is then purged with argon gas to maintain the oxygen content in the chamber below 200 ppm. Pressure maintenance is then initiated to maintain a constant chamber pressure of 0.6 MPa.

[0054] IV. Setting Additive Manufacturing Printing Parameters. Using Magic 3D modeling software, a block model for printing is created. Using BLT-BP software, printing parameters are set for the model, generating a scan path .nc file and saving it to the BLT-C400. Specifically, the printing idle speed is set to 1000 mm / min, the printing mode to platform mode, the scanning sequence to inner infill with an outer ring, the layer thickness to 0.4 mm, the number of outer rings to 0, the spot diameter to 1 mm, inner infill selected, the infill mode to continuous scanning mode, the path spacing to 1 mm, the rotation start angle to 0°, the rotation increment 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 collector fan speed to 2, and the lens gas speed to 20 L / min.

[0055] Through single-pass and double-pass additive manufacturing experiments with parameters including laser power and scanning rate, the optimal path spacing and layer thickness were obtained for each set of parameters. Ten orthogonal experiments were conducted on printing parameters including laser power, scanning speed, and powder feeding speed, and the above parameters were determined to be the optimal printing parameters, achieving a bulk density of 99.97% and a maximum pore size of 70 micrometers.

[0056] 5. Block printing is performed by alternating powder feeding with dual nozzles or by feeding powder in proportion to obtain layered titanium-based composite materials.

[0057] The specific details of the alternating powder delivery operation with dual nozzles are as follows:

[0058] Place TC4 metal powder into the first powder carrier container, and the mixed powder obtained in step three into the second powder carrier container. Set the rotation speed of the first powder feeder to 2% and the rotation speed of the second powder feeder to 0, and begin printing. After printing one layer, set the rotation speed of the first powder feeder to 0 and the rotation speed of the second powder feeder to 2%. After printing this layer, again set the rotation speed of the first powder feeder to 2% and the rotation speed of the second powder feeder to 0. Repeat this cycle until the printing operation is complete, obtaining TC4-TC4 / TiB. w In layered composite materials, the reinforcing phase in the layers exhibits a network-like microstructure.

[0059] The specific steps for distributing powder according to a set ratio are as follows:

[0060] During the first layer printing, the rotational speed of the first powder feeder connected to the first powder container is set to 2%, and the rotational speed of the second powder feeder connected to the second powder container is set to 0%. During the second layer printing, the rotational speed of the first powder feeder is 1.9%, and the rotational speed of the second powder feeder is 0.1%. Following this pattern, after each layer is printed, the rotational speed of the first powder feeder is reduced while the rotational speed of the second powder feeder is increased, while maintaining their sum at 2%, until printing is complete, resulting in a layered titanium-based composite material. In the layered titanium-based composite material, TiB...w The enhanced phase exhibits a gradient layered distribution characteristic.

[0061] Example 1

[0062] This embodiment prepares a layered titanium-based composite material, and the specific preparation method is carried out according to the following steps:

[0063] 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), with 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 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.

[0064] 2. Weigh 59.49g of TC4 powder and 0.51g of TiB2, and select 300g of ball milling beads with particle sizes of 6mm and 10mm. Ball milling is carried out in a ceramic ball mill jar. The ball milling speed is set to 225.5 rpm, the ball-to-powder ratio is 5:1, the ball milling time is 8h, and the ball milling atmosphere is argon.

[0065] 3. Place the mixed powder obtained in step 2 into a glass dish and then place it in a vacuum chamber for vacuum insulation. Maintain the temperature at 120°C for one hour under vacuum to ensure the powder is dry. Purge the BLT-C400 additive manufacturing equipment by introducing argon gas to reduce the oxygen content in the chamber to below 200 ppm. Then, activate the pressure holding function to maintain a constant chamber pressure of 0.6 MPa.

[0066] 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: print idle speed of 1000mm / min, print mode of platform mode, scan 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 increment angle of 90°, laser power of 750W, scan rate of 700mm / min, toner gas speed of 6L / min, dust removal fan speed of 2, and lens gas speed of 20L / min.

[0067] 5. Place the TC4 metal powder obtained in step 3 into the first powder carrier container, and the mixed powder obtained in step 3 into the second powder carrier container. Set the rotation speed of the first powder feeder to 2% and the rotation speed of the second powder feeder to 0, and start printing. After printing one layer, set the rotation speed of the first powder feeder to 0 and the rotation speed of the second powder feeder to 2%. After printing this layer, set the rotation speed of the first powder feeder to 2% and the rotation speed of the second powder feeder to 0 again. Repeat this cycle, changing the powder feeder speed after each layer is printed, until the printing operation is completed and TC4-TC4 / TiB is obtained. w Layered composite materials ( Figure 5 ).

[0068] This embodiment describes the preparation of TiB by real-time control of the powder feeding rate of the two powder feeders of the BLT-C400 additive manufacturing equipment. w The reinforcing phase exhibits a layered distribution in the titanium matrix composite material. The TC4 layer is approximately 1.25 mm thick and contains some TiB due to the Marangoni eddy phenomenon. w The reinforcing phase exhibits a uniform distribution. Figure 6 and Figure 7 ), TC4-TiB w The composite material layer is approximately 0.25 mm thick, and the reinforcing phase in this layer exhibits a network distribution. Figure 8 The two interfaces present a transition interface without a clear interface. Figure 9 In this embodiment, a tensile stress-strain curve is obtained through a tensile test. Figure 10 (Red). It can be seen that the modulus, strength, and elongation of the layered titanium-based composite material are all improved to a certain extent, with a strength reaching 1100 MPa and an elongation of 16.7%. This means that the current layered structure design is beneficial to improving the material's strength, toughness, and elongation, while significantly enhancing its resistance to damage and fracture energy absorption. From the fracture side of the tensile sample, it can be seen that many microcracks appeared during the tensile process. Figure 11 Compared to the Lüders band distribution of the TC4 tensile sample (). Figure 12 (a)), TC4-TiB w Layered composite materials exhibit a finer, shorter, denser, and deeper distribution of Lüders bands. Figure 12 (b)) These are all beneficial to improving the elongation and fracture absorption energy of the material.

[0069] Example 2

[0070] This embodiment prepares a layered titanium-based composite material. The specific preparation method is basically the same as that in Example 1. The difference is that in step five, after every two layers of printing, the speed of the powder feeder used for printing is changed until the printing operation is completed.

[0071] This embodiment describes the preparation of TiB by real-time control of the powder feeding rate of the two powder feeders of the BLT-C400 additive manufacturing equipment. w The reinforcing phase exhibits a layered distribution in the titanium matrix composite material. The TC4 layer is approximately 2.5 mm thick and contains some TiB due to the Marangoni eddy phenomenon. w The reinforcing phase exhibits a uniform distribution, TC4-TiB w The composite material layer is approximately 0.5 mm thick, and the reinforcing phase in this layer exhibits a network distribution. In this embodiment, a tensile stress-strain curve was obtained through a tensile test. Figure 10 (Purple). It can be seen that the modulus and strength of the layered titanium-based composite material are improved to a certain extent, with the strength reaching 1090 MPa and the elongation reaching 8.5%. This means that the current layered structure design is beneficial to the improvement of the material's strength and modulus, but it will slightly reduce the material's toughness and elongation.

[0072] Example 3

[0073] This embodiment prepares a layered titanium-based composite material. The specific preparation method is basically the same as that in Example 1. The difference is that in step five, after every three layers of printing, the speed of the powder feeder used for printing is changed until the printing operation is completed.

[0074] This embodiment describes the preparation of TiB by real-time control of the powder feeding rate of the two powder feeding tanks of the BLT-C400 additive manufacturing equipment. w The reinforcing phase exhibits a layered distribution in the layered titanium matrix composite material. The TC4 layer is approximately 3.75 mm thick and contains some TiB due to the Marangoni eddy phenomenon. w The reinforcing phase exhibits a uniform distribution, TC4-TiB w The composite material layer is approximately 0.75 mm thick, and the reinforcing phase in this layer exhibits a network distribution. In this embodiment, a tensile stress-strain curve was obtained through a tensile test. Figure 10 (Black). It can be seen that the modulus and strength of the layered titanium-based composite material are improved to a certain extent, with the strength reaching 1085 MPa and the elongation reaching 7%. This means that the current layered structure design is beneficial to the improvement of the material's strength and modulus, but it will reduce the material's toughness and elongation.

[0075] Example 4

[0076] This embodiment prepared a layered titanium-based composite material, and the content of the reinforcing phase inside the material exhibited a gradient distribution along the printing direction. 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 2%, and the rotation speed of the second powder feeder was set to 0%, and printing began. After eight layers were printed, the rotation speed of the first powder feeder was set to 1.5%, and the rotation speed of the second powder feeder was set to 0.5%. After eight layers were printed, the rotation speed of the first powder feeder was set to 1%, and the rotation speed of the second powder feeder was set to 1%. After eight layers were printed, the rotation speed of the first powder feeder was set to 0.5%, and the rotation speed of the second powder feeder was set to 1.5%. After eight layers were printed, the rotation speed of the first powder feeder was set to 0%, and the rotation speed of the second powder feeder was set to 2%. All printing was then completed, yielding TC4-TC4 / TiB. w Layered composite material, from bottom to top, TiB w The content shows a gradient distribution from 0% to 0.5%.

[0077] This embodiment describes the preparation of TiB by proportionally controlling the real-time powder feeding rate of the two powder feeding tanks of the BLT-C400 additive manufacturing equipment. w A layered titanium-based composite material in which the reinforcing phase exhibits a layered distribution, and TiB is present in the composite material. w The content exhibits a gradient distribution. In the first 8 layers (approximately 3.2 mm thick), the reinforcing phase content is 0, and its microstructure is shown in... Figure 13 In layers 9 to 16 (approximately 3.2 mm thick), the reinforcing phase content is 0.125%, and its microstructure is shown in... Figure 14 In layers 17 to 24 (approximately 3.2 mm thick), the reinforcing phase content is 0.25%, and its microstructure is shown in... Figure 15 In layers 25 to 32 (approximately 3.2 mm thick), the reinforcing phase content is 0.375%, and its microstructure is shown in... Figure 16 In layers 33 to 38 (approximately 2.4 mm thick), the reinforcing phase content is 0.5%, and its microstructure is shown in... Figure 17 As can be seen from the figure, TiB w The reinforcing phase still generally exhibits a network distribution in each layer, but as the content decreases, the continuity of the network changes, changing from a uniform network to a semi-continuous or discontinuous network structure, and the size of the network composed of the reinforcing phase also gradually increases.

[0078] Furthermore, experimental tests revealed that the layered titanium-based composite material obtained in this embodiment exhibits excellent mechanical properties, with improvements in both strength and modulus.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for preparing layered titanium-based composite materials based on direct energy deposition additive manufacturing, characterized in that, Specifically as follows: S1: Ti6Al4V metal powder and TiB2 powder, which have been vacuum dried respectively, are mixed and then ball-milled at low energy to achieve the embedding and adhesion of TiB2 powder on Ti6Al4V metal powder while ensuring good sphericity and integrity of the powder; the ball-milled product is then vacuum-dried to obtain a mixed powder; the Ti6Al4V metal powder is spherical with a particle size distribution of 65-150μm, and the TiB2 powder has a particle size distribution of 1-3μm; The low-energy ball milling process is as follows: 59.49 g of dried and pretreated Ti6Al4V metal powder and 0.51 g of TiB2 powder were weighed out, and 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 The mass fraction is 0.5%; TiB w Represents titanium boride whiskers; S2: Using additive manufacturing equipment, Ti6Al4V metal powder is placed into a first powder carrier canister and the mixed powder is placed into a second powder carrier canister; block printing is performed by alternately feeding powder with dual nozzles or feeding powder in proportion to obtain a layered titanium-based composite material. In step S2, the alternating powder delivery operation of the dual nozzles is as follows: S21: Set the rotation speed of the first powder feeder connected to the first powder tank to 2%, and the rotation speed of the second powder feeder connected to the second powder tank to 0, and then start printing one layer of material; S22: Set the rotation speed of the first powder feeder to 0 and the rotation speed of the second powder feeder to 2%, then start printing one layer of material; S23: Then repeat steps S21~S22 in sequence until the printing operation is completed, and obtain the layered titanium matrix composite material TC4-TC4 / TiB. w ;TC4-TC4 / TiB w In layers containing reinforcing phases, the reinforcing phases exhibit a network distribution; In step S2, the powder feeding operation according to the ratio is as follows: During the first layer printing, the rotational speed of the first powder feeder connected to the first powder container is set to 2%, and the rotational speed of the second powder feeder connected to the second powder container is set to 0%. During the second layer printing, the rotational speed of the first powder feeder is 1.9%, and the rotational speed of the second powder feeder is 0.1%. Following this pattern, after each layer is printed, the rotational speed of the first powder feeder is decreased while the rotational speed of the second powder feeder is increased, while maintaining their sum at 2%, until printing is complete, resulting in a layered titanium-based composite material. In the layered titanium-based composite material, TiB... w The enhanced phase exhibits a gradient layered distribution characteristic.

2. The method for preparing layered titanium-based composite materials based on direct energy deposition additive manufacturing according to claim 1, characterized in that, In step S1, the Hall flow rate of the Ti6Al4V metal powder is 28.1 s / 50 g, and the loose packing density is 2.37 g / cm³. 3 The tap density is 2.75 g / cm³. 3 .

3. The method for preparing layered titanium-based composite materials based on direct energy deposition 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 layered titanium-based composite materials based on direct energy deposition 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 equipment for gas purging to keep the oxygen content in the cabin below 200 ppm. Pressure holding is then activated to maintain a constant cabin pressure of 0.6 MPa.

5. The method for preparing layered titanium-based composite materials based on direct energy deposition additive manufacturing according to claim 1, characterized in that, 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. BLT-BP software was used to set the printing parameters for the 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 to be applied, the fill mode to 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 2, and the lens gas speed to 20 L / min.

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

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