Tungsten mesh reinforced high-temperature titanium alloy composite board and preparation method thereof

Abstract

The invention discloses a tungsten mesh reinforced high-temperature titanium alloy composite board and a preparation method thereof, and belongs to the technical field of composite materials. The technical problems that an existing high-temperature titanium alloy is low in room-temperature plasticity and difficult to deform are solved. A continuous tungsten mesh is introduced into a high-temperature titanium alloy plate, and the method specifically comprises the following steps that firstly, the tungsten mesh and the high-temperature titanium alloy plate are pretreated, then hot pressing treatment is conducted in a vacuum environment, and high-temperature titanium alloy flows in a high-temperature semi-solid state and is subjected to diffusion connection through meshes of the tungsten mesh; and finally, the obtained tungsten mesh reinforced high-temperature titanium alloy composite board is subjected to post-treatment. According to the method provided by the invention, the tungsten mesh is introduced into the diffusion interface of the high-temperature titanium alloy plate and the pressure is applied, so that the tungsten mesh and the high-temperature titanium alloy have a synergistic effect in the deformation process, the room-temperature plasticity of the titanium alloy is remarkably improved, and the titanium alloy is easy to deform. The preparation method provided by the invention is simple in process, remarkable in effect and easy to realize large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a tungsten mesh reinforced high-temperature titanium alloy composite plate and a preparation method thereof. Background Art

[0002] High-temperature titanium alloys are widely used in the fields of aerospace, energy and chemical engineering, shipbuilding, and medicine due to their excellent specific strength, corrosion resistance, and high-temperature performance. In the aerospace field, high-temperature titanium alloys are mainly used to manufacture key components such as engine compressor blades, turbine disks, and casings; in the energy and chemical engineering field, they are used to manufacture pipes and reactors that can withstand high temperatures and corrosion; in the medical field, they are used to manufacture artificial joints and implantable devices. With the continuous improvement of the requirements for material properties in modern industry, the application scope of high-temperature titanium alloys is further expanding.

[0003] Although high-temperature titanium alloys exhibit excellent performance in high-temperature environments, their room-temperature plasticity is low, deformation is difficult, and forming is challenging. This is mainly because the crystal structure of high-temperature titanium alloys is complex, and dislocation movement is restricted at room temperature, resulting in increased brittleness of the material. In addition, the high strength and low plasticity of high-temperature titanium alloys make it difficult to form them by traditional plastic processing methods (such as rolling, forging, etc.) at room temperature, limiting their further application.

[0004] To address the problem of difficult room-temperature deformation of high-temperature titanium alloys, there are mainly the following methods: alloying modification, heat treatment process optimization, superplastic forming, and composite material technology. Alloying modification: By adding alloying elements (such as aluminum, vanadium, molybdenum, etc.) to optimize the microstructure of high-temperature titanium alloys and improve their room-temperature plasticity. This method improves the processing performance of high-temperature titanium alloys to a certain extent, but may sacrifice some high-temperature performance. Heat treatment process optimization: By adjusting heat treatment process parameters (such as solution treatment, aging treatment, etc.) to improve the microstructure and mechanical properties of high-temperature titanium alloys. This method can effectively improve the plasticity of the material, but the process is complex and the cost is high. Superplastic forming: Utilize the superplastic behavior of high-temperature titanium alloys at specific temperatures and strain rates for forming. This method can achieve the forming of complex shapes, but requires high equipment and process control requirements. Composite material technology: By introducing reinforcing phases (such as fibers, particles, or network structures) to improve the mechanical properties of high-temperature titanium alloys. This method can significantly improve the strength and plasticity of the material while maintaining its high-temperature performance. However, after introducing reinforcing phases (such as fibers, particles) into the composite material, the overall hardness and brittleness of the composite material may increase, resulting in difficult room-temperature forming and machining. The difference in thermal expansion coefficients between the reinforcing phase and the titanium alloy matrix may lead to interfacial residual stresses, especially under high-temperature - room-temperature cyclic conditions, which are prone to initiate microcracks or interfacial debonding, reducing the load-bearing capacity of the material.

[0005] In summary, high-temperature titanium alloys have broad application prospects in multiple fields, but the problem of difficult room-temperature deformation restricts their further development. Existing solutions have improved the room-temperature plasticity of high-temperature titanium alloys to a certain extent, but each has its limitations, and it is still difficult to make the room-temperature plasticity of high-temperature titanium alloys meet the high requirements of current development. Summary of the Invention

[0006] In order to solve the problems of poor room-temperature plasticity and difficult deformation of high-temperature titanium alloys, the present invention provides a tungsten mesh-reinforced high-temperature titanium alloy composite plate and a preparation method thereof.

[0007] The technical solution of the present invention:

[0008] One of the purposes of the present invention is to provide a preparation method of a tungsten mesh-reinforced high-temperature titanium alloy composite plate, including:

[0009] Step 1: Grind the plate to be flat, remove the surface oil stain, remove the impurities on the plate by pickling, and wash and dry it with ethanol for standby;

[0010] Step 2: Take the tungsten mesh for alkali washing and dry it for standby;

[0011] Step 3: Take two plates reserved in Step 1 and a tungsten mesh with a coating in Step 4, spray the release agent on the two plates respectively, and then stack them in the order of plate, tungsten mesh with a coating, and plate from bottom to top. After stacking, tie and fix them with iron wire to obtain a composite plate;

[0012] Step 4: Spray the release agent on the part of the vacuum hot pressing and sintering mold that is in direct contact with the lower surface of the composite plate, and dry it after spraying;

[0013] Step 5: Place the composite plate sprayed with boron nitride in the mold for vacuum hot pressing and sintering, and cool down and take out the parts after sintering;

[0014] Step 6: Grind the surface of the composite plate after hot pressing and sintering to obtain a tungsten mesh-reinforced high-temperature titanium alloy composite plate;

[0015] In Step 3, the positions where the release agent is sprayed on the two plates are both: the other side of the contact surface in contact with the tungsten mesh with a coating.

[0016] Further limited, the material of the plate in Step 1 is a high-temperature titanium alloy.

[0017] Further limited, the liquid used in the pickling process in Step 1 is a mixed liquid composed of hydrofluoric acid, nitric acid and water in a volume ratio of 1:3:6.

[0018] Even further limited, the concentrations of hydrofluoric acid and nitric acid are both 90%.

[0019] Further limited, the pickling time in Step 1 is 1 - 4 min.

[0020] Further limitation: In step 2, the tungsten mesh is made by weaving, and the nodes are provided with solder joints.

[0021] Further limitation: In step 2, the solution used in the caustic washing process is a 50wt% NaOH solution, the caustic washing temperature is 80 - 100 °C, and the caustic washing time is 10 - 14 h.

[0022] Further limitation: In step 2, the caustic washing process is water bath heating.

[0023] Further limitation: In step 5, the vacuum degree of the vacuum hot pressing sintering is not less than 1×10 -2 Pa.

[0024] Further limitation: In step 5, the hot pressing sintering pressure is 10 - 30 MPa.

[0025] Further limitation: In step 5, the hot pressing sintering temperature is 860 - 960 °C.

[0026] The beneficial effects of the present invention are as follows:

[0027] The present invention provides a tungsten mesh reinforced high-temperature titanium alloy composite plate and its preparation method, which improves the room-temperature plasticity of the high-temperature titanium alloy plate. Compared with the prior art, the present invention also has the following advantages:

[0028] (1) The method provided by the present invention uses a tungsten mesh as the reinforcement, which is different from traditional reinforcement methods such as fiber, whisker or particle reinforcement. The tungsten mesh is a continuous reinforcement. This continuous network structure can form a uniform stress transfer path in the composite plate, avoiding the stress concentration problem caused by discontinuity during the reinforcement process of particle or fiber reinforcements. In addition, the network structure has a larger contact area with the high-temperature titanium alloy matrix material, and the interface combination is tighter, which can reduce the risk of interface debonding. Composites reinforced with traditional reinforcements such as fibers have obvious anisotropy (properties depend on the fiber direction), while the three-dimensional network structure of the present invention provides continuous support in multiple directions, making the mechanical properties of the composite plate closer to isotropic and beneficial to plastic deformation.

[0029] (2) The method provided by the present invention introduces tungsten mesh as a continuous reinforcement phase. The tungsten mesh acts as a continuous three-dimensional skeleton in the composite plate, which can evenly bear external loads and reduce local stress concentration in the high-temperature titanium alloy matrix. This uniform stress distribution delays the initiation of microcracks, allowing the composite plate to withstand greater plastic strain in the early stage of deformation. At the same time, through the vacuum hot pressing sintering process of the present invention, the tungsten mesh forms a chemically compatible and mechanically tough interface with the high-temperature titanium alloy matrix. During the deformation process, the interface between the tungsten mesh and the matrix can coordinate the plastic flow of the two phases and avoid interface debonding. The presence of the tungsten mesh hinders dislocation movement, but the continuous mesh structure allows dislocations to detour or climb in multiple directions in the high-temperature titanium alloy matrix, avoiding the rapid accumulation and work hardening of dislocations caused by traditional reinforcements (such as particles). Therefore, the tungsten mesh can coordinate the plastic flow of the titanium matrix alloy during the deformation of the titanium alloy matrix, effectively improving the problem of low room temperature plasticity of the high-temperature titanium alloy, making the high-temperature titanium alloy easier to process and form.

[0030] (3) The tungsten mesh used in the present invention has excellent thermal stability and strength at high temperatures. It can still work synergistically with the titanium matrix alloy under high temperature conditions, so that the composite plate still maintains excellent mechanical properties in a high-temperature environment, expanding the application scenarios of high-temperature titanium alloys. In addition, the present invention uses a woven tungsten mesh with welded nodes as a reinforcement, so that the reinforcement maintains its original shape during the incorporation into the high-temperature titanium alloy matrix, and does not debond, preventing the reinforcement from failing to play a reinforcing role. At the same time, the tungsten mesh with welded nodes is not easy to break and can better maintain its continuous shape, which greatly reduces the anisotropy of the composite plate.

[0031] (4) The present invention pre-treats the high-temperature titanium alloy and tungsten mesh and performs a vacuum hot pressing process. By applying pressure at high temperature, the surfaces of the tungsten mesh in contact with the titanium matrix alloy are bonded together through atomic diffusion to form a strong diffusion bonding interface. Since there is no melting during the diffusion bonding process, defects such as pores and cracks that may occur in fusion welding are avoided, which helps to improve the interface bonding strength between the reinforcement and the matrix, avoids the peeling problem between the reinforcement phase and the matrix, and is beneficial to improving the plastic deformation performance of the composite plate at room temperature.

[0032] (5) The present invention adopts vacuum hot pressing and diffusion bonding process to prepare tungsten mesh reinforced high-temperature titanium alloy plate, which has simple process steps and is easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of diffusion bonding of high-temperature titanium alloy plates through a tungsten mesh during vacuum hot pressing sintering in step 5 of Example 1, wherein 1 is a Ti60 high-temperature titanium alloy plate and 2 is a tungsten mesh;

[0034] Figure 2Schematic diagram of the vacuum hot pressing and sintering die in Example 1, where 1 is the punch, 2 is the die, and 3 is the spacer block;

[0035] Figure 3 Process flow chart of Example 1, where 1 is the Ti60 sheet or tungsten mesh, 2 is the Ti60 high-temperature titanium alloy sheet, 3 is the tungsten mesh, and 4 is the Ti60 high-temperature titanium alloy sheet;

[0036] Figure 4 Interface microstructure diagram of the tungsten mesh-reinforced Ti60 high-temperature titanium alloy composite sheet prepared in Example 1, where 1 is the tungsten wire of the tungsten mesh and 2 is the matrix microstructure of the Ti60 high-temperature titanium alloy;

[0037] Figure 5 High-temperature mechanical property comparison diagram of the Ti60 high-temperature titanium alloy sheet and the tungsten mesh-reinforced Ti60 high-temperature titanium alloy composite sheet prepared in Example 1 at 800 °C;

[0038] Figure 6 Room-temperature mechanical property comparison diagram of the tungsten mesh-reinforced Ti60 high-temperature titanium alloy composite sheets prepared in Examples 1 to 4. Detailed implementation manners

[0039] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0040] Many specific details are set forth in the following description to facilitate a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0041] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0042] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in this field, and those skilled in the art can obtain them through commercial channels without special instructions.

[0043] Example 1

[0044] Step 1: Cut the Ti60 high-temperature titanium alloy sheet into 50 mm × 50 mm and grind it flat to remove the surface oil. During the grinding stage of the sheet, ensure that the Ti60 high-temperature titanium alloy is smooth and has no obvious deformation. After grinding, pickle the alloy sheet with a liquid composed of hydrofluoric acid: nitric acid: water (volume ratio) of 1:3:6 for 2 minutes to remove impurities. After that, clean it with anhydrous ethanol, dry it, and set it aside for later use;

[0045] Step 2: Cut the tungsten mesh (100 mesh) into 50 mm × 50 mm in size, and clean the surface oil and other impurities with alcohol. The tungsten mesh used is made by weaving, and the nodes have solder joints. The tungsten mesh material is pure tungsten. Prepare a NaOH solution with a concentration of 50 wt%. Use the water bath method to heat the prepared NaOH solution to 100 °C, put the tungsten mesh in, ensure that the tungsten mesh is suspended in the NaOH solution, and all its planes are in contact with the NaOH solution. The cleaning time is 12 hours. After cleaning, clean the tungsten mesh with alcohol, dry it, and set it aside for later use;

[0046] Step 3: Take two pieces of the Ti60 high-temperature titanium alloy sheet prepared in Step 1 and one piece of the tungsten mesh prepared in Step 2. Spray the release agent boron nitride on the two Ti60 high-temperature titanium alloy sheets respectively. Only spray one side of the sheet, and there is no need to spray both sides. After spraying boron nitride, dry it. Then stack them in order from bottom to top as Ti60 high-temperature titanium alloy sheet, tungsten mesh, and Ti60 high-temperature titanium alloy sheet. Among them, the side of the bottom Ti60 high-temperature titanium alloy sheet with boron nitride sprayed is downward, and the side of the top Ti60 high-temperature titanium alloy sheet with boron nitride sprayed is upward, that is, the positions where the two sheets are sprayed with the release agent are on the other side of the contact surface with the tungsten mesh. To keep the positions of the Ti60 high-temperature titanium alloy sheet and the tungsten mesh fixed during the vacuum hot pressing sintering process, tie the stacked sheets and the tungsten mesh firmly with a wire with a diameter of 0.1 mm to obtain a composite sheet with the combination form of Ti60 high-temperature titanium alloy / tungsten mesh / Ti60 high-temperature titanium alloy;

[0047] Step 4: Spray the release agent boron nitride on the part of the vacuum hot pressing sintering mold that is in direct contact with the lower surface of the composite sheet, and dry it with a hair dryer after spraying;

[0048] Step 5: Place the composite sheet in the vacuum hot pressing sintering mold, then put the composite sheet together with the vacuum hot pressing sintering mold into the vacuum hot pressing sintering furnace, evacuate the vacuum hot pressing equipment to 1×10 -2 Pa, set the heating temperature to 900 °C, the holding time to 120 minutes, the pressure to 7500 Kg (30 MPa), and the heat preservation and pressure holding time to 2 hours. After setting the parameters, carry out vacuum hot pressing sintering. After sintering, cool it down to room temperature and take out the parts;

[0049] Step 6: Grind the combined plates after vacuum hot pressing and sintering to remove the surface interference layer, obtaining a tungsten mesh reinforced Ti60 high-temperature titanium alloy composite plate.

[0050] During the vacuum hot pressing and sintering forming process in Step 5 of this embodiment, the deformation process of the Ti60 high-temperature titanium alloy plate is as Figure 1 shown. When the temperature rises to the deformation temperature range of the Ti60 high-temperature titanium alloy plate, the plate gradually softens, meets the Ti60 high-temperature titanium alloy on the other side through the mesh holes of the tungsten mesh, and the two undergo element diffusion and are then connected together.

[0051] The schematic diagram of the vacuum hot pressing and sintering die used in this embodiment is as Figure 2 shown. The schematic diagram of the process flow of this embodiment is as Figure 3 shown.

[0052] Cut the tungsten mesh reinforced Ti60 high-temperature titanium alloy composite plate to obtain metallographic test specimens and mechanical property test specimens, and conduct corresponding metallographic tests and mechanical property tests. Observe the microstructure of the tungsten mesh reinforced Ti60 high-temperature titanium alloy composite plate formed in this embodiment, and the results are as Figure 4 shown, Figure 4 which is a cross-sectional view of a local area of the composite plate in the horizontal direction. It can be seen that the tungsten mesh is evenly embedded in the Ti60 high-temperature titanium alloy matrix structure, the diffusion interface between the tungsten mesh and the alloy matrix diffuses well, and the shape of the tungsten wires in the tungsten mesh is intact and no obvious change occurs. The mechanical property curve of the tungsten mesh reinforced Ti60 high-temperature titanium alloy composite plate prepared in this embodiment at 800 °C and a strain rate of 0.001 is as Figure 5 shown. It can be seen that the ultimate tensile strength of the titanium alloy composite plate with the tungsten mesh added is higher than that of the non-reinforced Ti60 high-temperature titanium alloy plate. This is because tungsten has strong thermal stability and still has good strengthening effect at high temperatures, thus improving the ultimate tensile strength of the Ti60 high-temperature titanium alloy matrix.

[0053] Example 2

[0054] The difference between this embodiment and Example 1 is that the mesh number of the tungsten mesh is 10 meshes, and the remaining process steps and parameter settings are the same as those in Example 1.

[0055] Example 3

[0056] The difference between this embodiment and Example 1 is that the mesh number of the tungsten mesh is 50 meshes, and the remaining process steps and parameter settings are the same as those in Example 1.

[0057] Example 4

[0058] The difference between this embodiment and Example 1 is that the mesh number of the tungsten mesh is 200 meshes, and the remaining process steps and parameter settings are the same as those in Example 1.

[0059] The room temperature mechanical property curves of the tungsten mesh-reinforced Ti60 high-temperature titanium alloy composite plates prepared in Examples 1 to 4 are as follows Figure 6 shown. The true stress-strain curve can reflect the magnitude of the tensile strength. It can be seen that although the tensile strength of the tungsten mesh-reinforced Ti60 high-temperature titanium alloy composite plate at room temperature decreases compared with that without reinforcement, it can still reach more than 700 MPa, which can meet the usage requirements in the civilian and industrial fields. After the tungsten mesh reinforcement, the plasticity of the Ti60 high-temperature titanium alloy is greatly improved, and with the gradual increase of the tungsten mesh mesh number, the effect of plasticity improvement is gradually enhanced. This is because the larger the tungsten mesh mesh number, the more uniform the stress distribution, the smaller the stress concentration, and there are more interfacial interactions. At the same time, the larger the mesh number means the denser the mesh holes. The fine mesh structure can better hinder crack propagation and allow more plastic deformation, further enhancing the effect of plasticity improvement.

[0060] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a tungsten mesh reinforced high-temperature titanium alloy composite plate, characterized in that, Including: Step 1: Polish the sheet to be flat, remove the surface oil stain, remove impurities on the sheet by pickling, and wash it with ethanol, then dry it for standby; Step 2: Take the tungsten mesh for alkali washing, and dry it for standby; Step 3: Take two sheets reserved in Step 1 and a tungsten mesh with a coating in Step 4, spray the release agent on the two sheets respectively, and then stack them in the order of sheet, tungsten mesh with a coating, and sheet from bottom to top. After stacking, tie and fix them with iron wire to obtain a composite sheet; Step 4: Spray the release agent on the part of the vacuum hot pressing and sintering die that is in direct contact with the lower surface of the composite sheet, and dry it after spraying; Step 5: Place the composite sheet sprayed with boron nitride in the die for vacuum hot pressing and sintering, and take out the part after cooling at the end of sintering; Step 6: Grind the surface of the composite sheet after hot pressing and sintering to obtain a tungsten mesh reinforced high-temperature titanium alloy composite sheet; The positions where the release agent is sprayed on the two sheets in Step 3 are both: the other side of the contact surface in contact with the tungsten mesh with a coating.

2. The preparation method according to claim 1, characterized in that, The material of the sheet in Step 1 is high-temperature titanium alloy.

3. The preparation method according to claim 1, characterized in that, The liquid used in the pickling process in Step 1 is a mixed liquid composed of hydrofluoric acid, nitric acid and water in a volume ratio of 1:3:6; the pickling time is 1 - 4 min.

4. The preparation method according to claim 3, characterized in that, The concentrations of hydrofluoric acid and nitric acid are both 90%.

5. The preparation method according to claim 1, wherein, The tungsten mesh in Step 2 is made by weaving method, and the nodes are provided with solder joints.

6. The preparation method according to claim 1, wherein, The solution used in the alkali washing process in Step 2 is a 50wt% NaOH solution.

7. The preparation method according to claim 1, wherein The alkali washing temperature in Step 2 is 80 - 100 °C, and the alkali washing time is 10 - 14 h.

8. The preparation method according to claim 1, characterized in that, The alkali washing process in Step 2 is water bath heating.

9. The preparation method according to claim 1, wherein In step 5, the vacuum degree of vacuum hot pressing sintering is not less than 1×10 -2 Pa, the hot pressing sintering pressure is 10 - 30 MPa, and the temperature is 860 - 960 °C.

10. A tungsten mesh-reinforced high-temperature titanium alloy composite sheet, characterized in that, Prepared by the method according to any one of claims 1 - 9.

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