A preparation method of a refractory Ta, Nb and TiC synergistically reinforced near-alpha titanium matrix composite

Abstract

The application discloses a preparation method of a refractory TaNb and TiC synergistically reinforced near-alpha titanium matrix composite material, and the method comprises the following steps: firstly, TaC ceramic powder, NbC ceramic powder, carbon black powder and titanium-based powder are ball-milled and mixed to obtain titanium-based composite powder wrapped by TaC, NbC and carbon black; and secondly, a refractory TaNb and TiC synergistically reinforced near-alpha titanium matrix composite material is obtained by spark plasma sintering. In the application, the TaC and NbC ceramic powder is used as the refractory element Ta, Nb source and carbon source, the carbon black powder is used as an additional carbon source, the different carbon sources are used to generate the small-size TiC ceramic phase which is distributed in a net-like and staggered manner and dispersedly in situ, the size distribution of the TiC ceramic phase is regulated, the solid solution strengthening effect of the refractory elements Ta and Nb on the matrix is synergistically improved, the room-temperature strength and high-temperature strength plasticity of the coupled reinforced near-alpha titanium matrix composite material are realized, and certain room-temperature processing performance is reserved.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composites, specifically relating to a method for preparing a near-α titanium matrix composite material synergistically reinforced by refractory Ta, Nb and TiC. Background Technology

[0002] Titanium-based composite materials are widely used in aerospace, military equipment, and other fields due to their excellent properties such as low density, high specific strength, high elastic modulus, high corrosion resistance, and high temperature resistance. This material has been used as a key structural component in aerospace vehicles, such as aircraft skin, structural frames, and tail fins. Especially as components located near heat sources, titanium-based composite materials exhibit superior heat resistance compared to traditional titanium alloys, thus possessing significant application value for national defense.

[0003] Elements such as B, C, N, and Si are often introduced into titanium-based composites to generate reinforcing phases such as TiB, TiC, TiN, and Ti5Si3. Among these, in-situ generated TiC ceramic particles are considered one of the reinforcing phases that can effectively improve the properties of titanium-based composites. However, due to the significant differences in physical properties such as elastic modulus and linear expansion coefficient between the ceramic phase and the titanium alloy matrix, deformation incompatibility between the two phases during loading at room temperature can occur, potentially leading to crack initiation. This can affect the room temperature strength and ductility of titanium-based composites to varying degrees.

[0004] Furthermore, although the introduction of a high volume fraction of ceramic reinforcing phase can improve the service temperature of the titanium alloy matrix, the strength will decrease rapidly with increasing temperature due to the high-temperature softening limitation of the titanium alloy matrix itself. In addition, excessive ceramic reinforcing phase will reduce the room temperature plasticity of the material and impair its processing performance.

[0005] Therefore, the challenge lies in designing and controlling the deformability of titanium-based composite materials so that they can maintain certain processing properties (strength and plasticity) at room temperature while also possessing excellent high-temperature strength. This would overcome and compensate for the previous technical bottleneck of titanium-based composite materials having either excellent room-temperature strength and plasticity or excellent high-temperature strength. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a method for preparing near-α titanium-based composite materials synergistically reinforced with refractory Ta, Nb, and TiC, addressing the shortcomings of the prior art. This method utilizes the synergistic effect of refractory elements Ta and Nb to improve the solid solution strengthening effect on the titanium matrix, and rationally controls the volume fraction and size distribution of the in-situ generated TiC ceramic phase. This coupled improvement enhances the deformation incompatibility between the titanium alloy matrix and the TiC ceramic reinforcing phase, thereby improving both room temperature strength and high-temperature ductility of the near-α titanium-based composite material while ensuring that it retains certain room temperature processing properties. This solves the problem in the prior art where titanium-based composite materials struggle to simultaneously possess excellent room temperature strength and high-temperature ductility.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb and TiC, characterized in that the method includes the following steps:

[0008] Step 1: Ball mill and mix TaC ceramic powder, NbC ceramic powder, carbon black powder and titanium-based powder to obtain titanium-based composite powder coated with TaC, NbC and carbon black.

[0009] Step 2: Perform discharge plasma sintering on the titanium-based composite powder coated with TaC, NbC and carbon black obtained in Step 1 to obtain a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb and TiC.

[0010] This invention uses TaC ceramic powder, NbC ceramic powder, and carbon black powder as additives. The additives and titanium-based powder are mechanically mixed and coated using low-energy ball milling to prepare a refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material that possesses certain room-temperature processing properties, high room-temperature strength, and high-temperature ductility. First, TaC and NbC ceramic powders are used as sources of Ta and Nb elements. Due to their large atomic radii, Ta and Nb dissolve into the titanium matrix, providing solid solution strengthening and improving the strength of the titanium matrix and the compatibility between the titanium alloy matrix and the ceramic phase. Second, due to their high melting points and chemical stability, Ta and Nb can inhibit grain growth, improving the high-temperature mechanical properties of the near-α titanium-based composite material. Third, since the synergistic effect of Ta and Nb is non-linear, this invention controls the ratio of TaC and NbC ceramic powders to provide Ta and Nb, thus synergistically improving the mechanical properties of the near-α titanium-based composite material while preserving certain processing properties.

[0011] Meanwhile, the TaC ceramic powder, NbC ceramic powder, and carbon black powder added in this invention are all carbon sources for in-situ generated TiC ceramic particles. This results in a network-like interwoven distribution of the TiC ceramic reinforcing phase in the near-α titanium-based composite material, which acts as a pinning agent for dislocations formed during deformation, all contributing to the strength of the near-α titanium-based composite material. Specifically, the dispersed small-sized TiC reinforcing phase, generated in-situ from micro / nano-sized TaC and NbC carbon sources, reduces stress concentration and plasticity loss. A small amount of carbon source dissolved into the titanium alloy matrix provides solid solution strengthening, improving the room temperature and high temperature strength of the near-α titanium-based composite material. Furthermore, this invention utilizes a small amount of carbon from the TaC and NbC ceramic powders to replace part of the carbon black powder. This ensures that carbon black serves as an additional carbon source to provide room temperature and high temperature strength while avoiding the problem of excessive carbon black agglomerating into large-sized TiC during spark plasma sintering, which would cause damage to plasticity greater than its contribution to strength.

[0012] Therefore, by adding TaC ceramic powder, NbC ceramic powder, and carbon black powder and controlling their proportions, this invention enables Ta and Nb to be solid-solution strengthened in the titanium matrix and hinder grain growth, and generates a small-sized TiC reinforcing phase that is distributed in a network and dispersed. This coupled and enhances the room temperature and high temperature strength of the near-α titanium matrix composite material, while retaining certain room temperature processing properties.

[0013] The above-mentioned method for preparing a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb and TiC is characterized in that the titanium-based powder in step one is a near-α titanium-based powder TA11, TA15 or TA19, and the titanium-based powder is a spherical powder with a particle size of 15μm to 53μm.

[0014] The above-mentioned method for preparing a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb, and TiC is characterized in that, in step one, the TaC ceramic powder and the NbC ceramic powder are particles with a particle size of 0.1 μm to 1 μm. This invention improves the dispersibility of ceramic powders in a titanium-based matrix by using micro / nano-sized TaC and NbC ceramic powders, and also generates small-sized TiC in situ, resulting in more uniform and easier solid solution of TaNb.

[0015] The preparation method of the above-mentioned refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material is characterized in that, in step one, the total mass percentage of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder in the titanium-based composite powder is 0.3%~3%, wherein the percentage of carbon black powder is 0.1%~1%, and the mass ratio of TaC ceramic powder to NbC ceramic powder is 1:9~9:1; the ball milling mixing is performed at a speed of 150rpm~250rpm, a ball-to-powder ratio of 3~6:1, and a milling time of 6h~10h, and the ball milling mixing includes two stages: in the first stage, half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder are added, and the milling time is 1h~3h; in the second stage, the remaining half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder are added, and the milling time is 5h~7h. This invention ensures that the raw material powders are fully mixed by employing a two-stage ball milling process.

[0016] The preparation method of the above-mentioned refractory Ta, Nb and TiC synergistically reinforced near-α titanium matrix composite material is characterized in that the discharge plasma sintering process in step two is as follows: the titanium matrix composite powder coated with TaC, NbC and carbon black is placed in a graphite mold and held at a sintering temperature of 900℃~1100℃ and a sintering pressure of 40MPa~50MPa for 5min~10min.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. This invention uses micro / nano TaC and NbC ceramic powders as sources of refractory elements Ta and Nb, and carbon sources, and carbon black powder as an additional carbon source. By utilizing different carbon sources, small-sized TiC ceramic phases with a network-like interlaced and dispersed distribution are generated in situ, which effectively enhances the strength of the composite material and reduces plasticity loss. At the same time, the nonlinear synergistic solid solution strengthening effect of Ta and Nb is used to strengthen the titanium matrix and improve the compatibility between the matrix and the ceramic phase. It also replaces part of the carbon black powder to limit the strengthening effect of the additional carbon source in generating the reinforcing phase and the plasticity loss effect, thereby achieving room temperature strength and high temperature plasticity of the coupled strengthened near-α titanium matrix composite material, while retaining certain room temperature processing performance.

[0019] 2. This invention uses micro-nano TaC and NbC ceramic particles as additives containing refractory elements, which are uniformly embedded on carbon black-coated titanium-based powder during low-energy ball milling. In the subsequent spark plasma sintering process, Ta and Nb can be generated in situ in a short time to dissolve into the titanium alloy matrix and form a fine TiC ceramic reinforcing phase. Compared with the use of other large-particle element powders, this invention effectively improves the solid solution effect and the utilization rate of refractory elements, avoids the segregation and enrichment of refractory elements, shortens the reaction time, reduces energy consumption and costs, and has simple process steps and wide application range. It is a promising method for the industrial preparation of titanium-based composite materials with high efficiency and low energy consumption.

[0020] 3. The refractory Ta, Nb and TiC synergistically reinforced near-α titanium matrix composite material prepared by this invention exhibits superior room temperature processing performance and excellent room temperature strength, while also possessing superior high temperature mechanical properties. It exhibits a tensile strength of 1400 MPa and an elongation of 4.5% at room temperature, and a high temperature strength of 600 MPa and an elongation of more than 63% at 700℃, which are higher than the comprehensive room temperature and high temperature mechanical properties of traditional titanium matrix composite materials.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a scan image of the titanium-based composite powder coated with TaC, NbC and carbon black prepared in Example 1 of the present invention at a scale bar of 100 μm.

[0023] Figure 2 The images show the XRD patterns of the refractory Ta, Nb and TiC synergistically reinforced near-α titanium matrix composites prepared in Examples 2-3 of this invention. Detailed Implementation

[0024] In Examples 1-7 and Comparative Example 1 of this invention, the titanium-based powder used is spherical powder with a particle size of 15μm to 53μm, the TaC ceramic powder used is particle with a particle size of 0.1μm to 1μm, and the NbC ceramic powder used is particle with a particle size of 0.1μm to 1μm.

[0025] Example 1

[0026] This embodiment includes the following steps:

[0027] Step 1: Weigh 0.5% TaC ceramic powder, 0.5% NbC ceramic powder, 0.5% carbon black powder, and 98.5% TA19 titanium alloy powder by mass percentage. Then, place all the TA19 titanium alloy powder and half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder into a stainless steel ball mill jar and add stainless steel grinding balls. The ball-to-material ratio is 3:1. Mix the materials using a planetary ball mill at 200 rpm for 1 hour. Then, add the remaining half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder and ball mill at 200 rpm for 7 hours to obtain a titanium-based composite powder coated with TaC, NbC, and carbon black.

[0028] Step 2: The titanium-based composite powder coated with TaC, NbC and carbon black obtained in Step 1 is placed into a graphite mold for discharge plasma sintering. The sintering temperature is 1000℃, the sintering pressure is 40MPa, and the holding time is 10min. After cooling, the powder is demolded to obtain a near-α titanium-based composite material with synergistic reinforcement of refractory Ta, Nb and TiC.

[0029] Figure 1 This is a scan image of the titanium-based composite powder coated with TaC, NbC, and carbon black prepared in this embodiment at a scale bar of 100 μm. Figure 1 It can be seen that the TaC, NbC and carbon black added to the titanium-based composite powder are uniformly dispersed on the surface of the TA19 titanium alloy powder, and the titanium-based composite powder maintains good sphericity.

[0030] Example 2

[0031] The difference between this embodiment and Embodiment 1 is that in step one, 0.3% TaC ceramic powder and 0.7% NbC ceramic powder are weighed according to their mass percentage content.

[0032] Example 3

[0033] The difference between this embodiment and Embodiment 1 is that in step one, 0.7% of TaC ceramic powder and 0.3% of NbC ceramic powder are weighed according to their mass percentage content.

[0034] Figure 2 The images show the XRD patterns of the refractory Ta, Nb, and TiC synergistically reinforced near-α titanium matrix composites prepared in Examples 2-3 of this invention. Figure 2No peaks of the added TaC, NbC ceramic powder and carbon black powder were observed. Only the α-Ti and β-Ti phases in the TA19 titanium alloy matrix and the TiC ceramic peak generated in situ were observed. This indicates that the TaC and NbC ceramic powder added in the preparation method of this invention has fully reacted, and the refractory elements Ta and Nb have dissolved into the TA19 titanium alloy matrix. The carbon source generates the TiC reinforcing phase in situ, achieving the purpose of synergistic strengthening by solid solution strengthening of refractory elements and TiC reinforcing phase, thereby improving the room temperature strength and high temperature plasticity of near-α titanium-based composite materials.

[0035] Example 4

[0036] The difference between this embodiment and Embodiment 1 is that in step one, 0.9% of TaC ceramic powder and 0.1% of NbC ceramic powder are weighed according to their mass percentage content.

[0037] Example 5

[0038] The difference between this embodiment and Embodiment 1 is that in step one, 0.1% of TaC ceramic powder and 0.9% of NbC ceramic powder are weighed according to their mass percentage content.

[0039] Comparative Example 1

[0040] The difference between this comparative example and Example 1 is that in step one, 1.0% of NbC ceramic powder, 0.5% of carbon black powder, and 98.5% of TA19 titanium alloy powder were weighed by mass percentage.

[0041] The room temperature mechanical properties and high temperature (700℃) mechanical properties of the near-α titanium-based composite materials prepared in Examples 1-5 and Comparative Example 1 of this invention were tested using a universal testing machine. The results are shown in Table 1 and Table 2, respectively.

[0042] Table 1

[0043]

[0044] Table 2

[0045]

[0046] As shown in Tables 1 and 2, the high-temperature tensile strength of the refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composites prepared in Examples 1-5 of this invention is superior to that of Comparative Example 1, and the high-temperature elongation at break is mostly superior to that of Comparative Example 1. This indicates that compared to Comparative Example 1, which only added NbC ceramic powder and carbon black powder for reinforcement, the near-α titanium-based composites prepared by the present invention using TaNb and TiC synergistic reinforcement have superior high-temperature mechanical properties. Among them, the high-temperature elongation at break of the refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite prepared in Example 4 is lower than that of Comparative Example 1, indicating that the present invention needs to control the proportion of the added ceramic powders TaC, NbC, and carbon black powder to effectively exert the synergistic reinforcing effect of TaNb solid solution reinforcement and the generated TiC ceramic reinforcement, and obtain near-α titanium-based composites with better high-temperature mechanical properties. Meanwhile, the room temperature tensile strength and room temperature elongation at break of the refractory Ta, Nb and TiC synergistically reinforced near-α titanium-based composite materials prepared in Examples 1-5 of this invention are sometimes better than Comparative Example 1 and sometimes worse than Comparative Example 1. This further illustrates that the present invention needs to control the ratio of the additive ceramic powders TaC, NbC and carbon black powder to ensure that the near-α titanium-based composite material obtains excellent high-temperature mechanical properties and room temperature mechanical properties at the same time. Among them, the near-α titanium-based composite material prepared when the mass ratio of TaC ceramic powder to NbC ceramic powder is controlled at 3:7 in Example 2 achieves the best level of high-temperature mechanical properties and room temperature mechanical properties.

[0047] Example 6

[0048] This embodiment includes the following steps:

[0049] Step 1: Weigh 0.1% TaC ceramic powder, 0.1% NbC ceramic powder, 0.1% carbon black powder, and 99.7% TA11 titanium alloy powder by mass percentage. Then, place all the TA11 titanium alloy powder and half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder into a stainless steel ball mill jar and add stainless steel grinding balls. The ball-to-material ratio is 5:1. Mix the materials using a planetary ball mill at 150 rpm for 1 hour. Then, add the remaining half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder and ball mill at 150 rpm for 5 hours to obtain a titanium-based composite powder coated with TaC, NbC, and carbon black.

[0050] Step 2: The titanium-based composite powder coated with TaC, NbC and carbon black obtained in Step 1 is placed into a graphite mold for discharge plasma sintering. The sintering temperature is 900℃, the sintering pressure is 45MPa, and the holding time is 5min. After cooling, the powder is demolded to obtain a near-α titanium-based composite material with synergistic reinforcement of refractory Ta, Nb and TiC.

[0051] Example 7

[0052] This embodiment includes the following steps:

[0053] Step 1: Weigh 1.8% TaC ceramic powder, 0.2% NbC ceramic powder, 1% carbon black powder, and 97% TA15 titanium alloy powder by mass percentage. Then, place all the TA15 titanium alloy powder and half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder into a stainless steel ball mill jar and add stainless steel grinding balls. The ball-to-material ratio is 6:1. Mix the materials using a planetary ball mill at 250 rpm for 3 hours. Then, add the remaining half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder and ball mill at 250 rpm for 7 hours to obtain a titanium-based composite powder coated with TaC, NbC, and carbon black.

[0054] Step 2: The titanium-based composite powder coated with TaC, NbC and carbon black obtained in Step 1 is placed into a graphite mold for discharge plasma sintering. The sintering temperature is 1100℃, the sintering pressure is 50MPa, and the holding time is 8min. After cooling, the powder is demolded to obtain a near-α titanium-based composite material with synergistic reinforcement of refractory Ta, Nb and TiC.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb, and TiC, characterized in that, The method includes the following steps: Step 1: Ball mill and mix TaC ceramic powder, NbC ceramic powder, carbon black powder, and titanium-based powder to obtain a titanium-based composite powder coated with TaC, NbC, and carbon black; the titanium-based powder is a near-α titanium-based powder TA11, TA15, or TA19; the total mass percentage of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder in the titanium-based composite powder is 0.3%~3%, of which the percentage of carbon black powder is 0.1%~1%, and the mass ratio of TaC ceramic powder to NbC ceramic powder is 3:7; Step 2: Perform discharge plasma sintering on the titanium-based composite powder coated with TaC, NbC and carbon black obtained in Step 1 to obtain a near-α titanium-based composite material synergistically reinforced by refractory Ta, Nb and TiC.

2. The method for preparing a refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material according to claim 1, characterized in that, The titanium-based powder mentioned in step one is a spherical powder with a particle size of 15μm~53μm.

3. The method for preparing a refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material according to claim 1, characterized in that, The TaC ceramic powder mentioned in step one has particles with a particle size of 0.1μm to 1μm, and the NbC ceramic powder has particles with a particle size of 0.1μm to 1μm.

4. The method for preparing a refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material according to claim 1, characterized in that, The ball milling speed for the ball milling mixture described in step one is 150 rpm to 250 rpm, the ball-to-material ratio is 3 to 6:1, and the ball milling time is 6 to 10 hours. The ball milling mixture includes two stages: in the first stage, half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder are added, and the ball milling time is 1 to 3 hours; in the second stage, the remaining half of the additives TaC ceramic powder, NbC ceramic powder, and carbon black powder are added, and the ball milling time is 5 to 7 hours.

5. The method for preparing a refractory Ta, Nb, and TiC synergistically reinforced near-α titanium-based composite material according to claim 1, characterized in that, The discharge plasma sintering process described in step two is as follows: the titanium-based composite powder coated with TaC, NbC and carbon black is placed in a graphite mold and held at a sintering temperature of 900℃~1100℃ and a sintering pressure of 40MPa~50MPa for 5min~10min.

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