High-strength and high-plasticity titanium-based composite material with heterogeneous structure and preparation method thereof

Abstract

This invention discloses a method for preparing a high-strength, high-plasticity-matching heterogeneous titanium-based composite material. The method includes: 1. Dispersing highly active alumina nanoparticles after adjusting their activity to obtain an alumina nanoparticle suspension; 2. Adding titanium alloy powder to obtain a mixed solution of titanium alloy powder and alumina; 3. Evaporating to obtain titanium alloy powder with a core-shell structure pre-coated nano-alumina; 4. Vacuum treatment followed by low-energy ball milling to obtain nano-alumina-titanium core-shell structure powder; 5. Low-temperature short-time sintering to obtain the heterogeneous titanium-based composite material. This invention, by adjusting the activity of highly active γ-structure alumina nanoparticles to form an alumina-titanium core-shell structure powder, followed by low-temperature short-time sintering, greatly promotes the diffusion, migration, and interaction between highly active and high-defect γ-structure alumina and titanium, obtaining an ultrafine, multi-level gradient reinforcing phase, forming a heterogeneous titanium-based composite material, and significantly improving the strength-plasticity matching performance of the titanium-based composite material.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite material preparation technology, specifically relating to a high-strength and plasticity matched heterostructure titanium matrix composite material and its preparation method. Background Technology

[0002] Since the mid-1950s, titanium has emerged as the "third metal" after ferroalloys such as steel and aluminum. Compared to other metals and alloys, titanium possesses numerous superior properties: low density, better resistance at extremely high or low temperatures, strong corrosion resistance, low thermal conductivity, near-non-magnetic properties, and high specific strength. After decades of development, the applications of titanium have expanded beyond military and high-altitude / ultra-high-altitude flight. Currently, titanium is used in various sectors of society, and its frequency of use in our daily lives has greatly increased.

[0003] However, with the increasing demand for high-performance materials in fields such as aerospace, such as the need for lightweight and high-strength materials in hypersonic aircraft and next-generation high-performance aero engines, the design performance of titanium alloys is increasingly unable to meet the requirements of various applications. Therefore, a trend of shifting from titanium alloys to titanium-based composites has emerged. Titanium-based composites have not only gradually replaced titanium alloys in some fields but have also been applied to high-requirement aerospace products, as mentioned above. However, in previous studies, researchers mostly chose carbon sources (such as graphene, diamond, and carbon nanotubes) and boron sources (such as boron powder, titanium diboride, and boron carbide) as reinforcing phases for titanium-based composites. However, the introduction of traditional carbon and boron sources often leads to the enrichment of the reinforcing phase at the shell, resulting in an imbalance between the strength and plasticity of the titanium alloy material. Therefore, selecting a reinforcing phase that achieves a good balance between strength and plasticity in titanium-based composites has become a major challenge in ensuring that titanium-based composites meet the required performance. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for preparing a high-strength, high-plasticity-matching heterogeneous titanium-based composite material, addressing the shortcomings of the prior art. This method involves adjusting the activity of highly active γ-structured alumina nanoparticles and then sequentially pre-coating them with titanium alloy powder in a liquid phase followed by low-energy ball milling to form an alumina-titanium core-shell structure powder. This powder is then subjected to low-temperature, short-time sintering, which greatly promotes the diffusion, migration, and interaction between the highly active and high-defect γ-structured alumina and titanium, thereby obtaining an ultrafine, multi-level gradient reinforcing phase and forming a heterogeneous titanium-based composite material. This significantly improves the strength-plasticity matching performance of the titanium-based composite material.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for preparing a high-strength and high-plasticity matched heterostructure titanium-based composite material, characterized in that the method includes the following steps:

[0006] Step 1: Adjust the activity of the highly active alumina nanoparticles, and then disperse them in an ethanol solution with the assistance of a dispersant to obtain an alumina nanoparticle suspension; the highly active alumina nanoparticles are highly active γ-structured alumina.

[0007] Step 2: Add titanium alloy powder to the alumina nanoparticle suspension obtained in Step 1 while stirring at room temperature to obtain a mixed solution of titanium alloy powder and alumina.

[0008] Step 3: Stir and evaporate the mixed solution of titanium alloy powder and alumina obtained in Step 2 under water bath conditions to obtain titanium alloy powder with pre-coated nano-alumina structure.

[0009] Step 4: Vacuum treatment is performed on the pre-coated nano-alumina titanium alloy powder obtained in Step 3 to remove the dispersant, and then low-energy ball milling is performed to coat it to obtain nano-alumina-titanium core-shell structure powder.

[0010] Step 5: The nano-alumina-titanium core-shell structure powder obtained in Step 4 is subjected to low-temperature short-time sintering to obtain a heterostructure titanium-based composite material; the tensile strength of the heterostructure titanium-based composite material is 540MPa~1200MPa, and the elongation is 7%~23%.

[0011] This invention first modulates the activity of highly active γ-structured alumina nanoparticles to improve activity, increase defects, optimize dispersibility, and reduce particle size, giving them high defects and activity. This creates conditions for their full interaction, reaction, dissolution, diffusion, and precipitation with titanium alloy powder. Then, ethanol solution is used as the dispersion medium for assisted dispersion to obtain a suspension of highly active and highly defective alumina nanoparticles, creating conditions for their uniform coating of titanium alloy powder. Liquid-phase pre-coating and low-energy ball milling are then sequentially employed to obtain alumina-titanium core-shell structure powder with a uniformly coated surface of highly active and highly defective γ-structured alumina, improving coating uniformity and bonding. Finally, low-temperature short-time sintering greatly promotes the diffusion, migration, and interaction between highly active and highly defective γ-structured alumina and titanium, precipitating ultrafine, multi-level gradient reinforcing phases from the shell to the grain boundaries and within the grains, forming a heterostructured titanium-based composite material. This significantly improves the strength and plasticity matching performance of the titanium-based composite material.

[0012] The above-mentioned method for preparing a high-strength, high-plasticity heterostructure titanium-based composite material is characterized in that the highly active alumina nanoparticles in step one have a porous structure, an average particle size of less than 50 nm, and a specific surface area of ​​greater than 50 m². 2 / g, the method for adjusting the activity is ultrasonic or ball milling. Compared with alumina with other structures, the highly active alumina nanoparticles preferred in this invention have high porosity, high defects, high reactivity and excellent dispersibility, which provides a good foundation for their uniform coating, reaction and diffusion with titanium and titanium alloys. The above-mentioned activity adjustment method can further improve the defects, activity and dispersibility of alumina.

[0013] The method for preparing a high-strength, high-plasticity heterostructure titanium-based composite material described above is characterized in that the dispersant in step one is polyethylene glycol and PVP, and the mass of the dispersant is less than 0.3% of the mass of the ethanol solution. This preferred dispersant and dosage promote more uniform dispersion of the alumina nanoparticles after activity adjustment.

[0014] The method for preparing a high-strength, high-plasticity heterostructure titanium-based composite material described above is characterized in that the rotational speed used in step four, the low-energy ball milling coating, is less than 350 r / min. This preferred rotational speed ensures uniform mixing while avoiding deformation of the titanium alloy.

[0015] The method for preparing a high-strength, high-plasticity heterostructure titanium-based composite material described above is characterized in that the low-temperature short-time sintering in step five is high-current plasma-activated vacuum hot-pressing sintering, with a sintering temperature of 800℃~1100℃, a holding time of less than 30min, and a sintering pressure greater than 10MPa. This preferred high-current combined with plasma sintering method significantly promotes the atomic migration rate. On the one hand, under the above-mentioned sintering temperature, holding time, and pressure conditions, the heterostructure titanium-based composite material becomes nearly completely dense. On the other hand, it promotes the dissolution, diffusion, and precipitation of highly active and highly porous alumina nanoparticles with the titanium or titanium alloy matrix, thereby ensuring the formation of the heterostructure.

[0016] The above-mentioned method for preparing a high-strength and plasticity-matched heterostructure titanium-based composite material is characterized in that the heterostructure in the heterostructure titanium-based composite material in step five is a multi-level gradient distribution structure of titanium-alumina-containing precipitates that are dissolved and diffused into the inner titanium matrix by highly active γ-alumina nanoparticles, and precipitated on the shell to the titanium matrix grains, intragranular boundaries and dislocations.

[0017] In addition, the present invention also discloses a high-strength and high-plasticity matched heterostructure titanium-based composite material, characterized in that it is prepared by the above-described method.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This invention modulates the activity of highly active γ-structured alumina nanoparticles to give them high defects and high activity. Then, it sequentially pre-coats titanium alloy powder with liquid phase and then coats it with low-energy ball milling to form an alumina-titanium core-shell structure powder. Finally, it undergoes low-temperature short-time sintering, which greatly promotes the diffusion, migration and interaction between highly active and highly defective γ-structured alumina and titanium, thereby obtaining an ultrafine multi-level gradient reinforcing phase and forming a heterostructured titanium-based composite material, which significantly improves the strength and plasticity matching performance of the titanium-based composite material.

[0020] 2. The highly active γ-structured alumina used in this invention is widely available, inexpensive, and has a simple preparation process. It also has high defects and high activity, which is significantly better than traditional crystalline carbon such as graphene, diamond, carbon nanotubes, and onion carbon.

[0021] 3. The present invention uses ethanol solution as a dispersion medium to assist in the dispersion of highly active alumina nanoparticles after the activity has been adjusted, thus creating conditions for their uniform coating.

[0022] 4. The present invention adopts the method of "liquid phase pre-coating + low-energy dry grinding coating" to obtain alumina-titanium core-shell structure powder with uniform coating of highly active and high-defect γ-structure alumina. Its coating uniformity and bonding state are significantly better than those of traditional methods.

[0023] 5. The present invention employs low-temperature short-time sintering, which greatly promotes the diffusion, migration and interaction of highly active and high-defect γ-structured alumina and titanium. Ultrafine multi-level gradient reinforcing phases are precipitated from the shell to the grain boundaries and within the grains, forming a heterostructured titanium-based composite material, which significantly improves the strength and plasticity matching performance of the titanium-based composite material.

[0024] 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

[0025] Figure 1 This is an electron microscope image of the alumina-titanium core-shell structure powder prepared in Example 2 of the present invention.

[0026] Figure 2 This is an electron microscope image of the heterostructured titanium alloy composite material prepared in Example 2 of the present invention.

[0027] Figure 3 The tensile property curves are for the heterostructure titanium alloy composite materials prepared in Examples 1 to 4 of this invention and the titanium alloy material prepared in Comparative Example 1.

[0028] Figure 4 The tensile property curves are shown for the heterostructure titanium alloy composite materials prepared in Examples 5 and 6 of this invention and the titanium alloy material prepared in Comparative Example 2. Detailed Implementation

[0029] Example 1

[0030] This embodiment includes the following steps:

[0031] Step 1: The activity of the highly active alumina nanoparticles is adjusted, and then dispersed in an ethanol solution with the assistance of dispersants polyethylene glycol (PEG) and PVP to obtain an alumina nanoparticle suspension; the highly active alumina nanoparticles are highly active γ-structured alumina with an average particle size of less than 20 nm and a specific surface area of ​​greater than 100 m². 2 / g, the method for adjusting the activity is ultrasonic treatment for 3 hours; the mass of the dispersant is 0.1% of the mass of the ethanol solution;

[0032] Step 2: Add titanium alloy powder to the alumina nanoparticle suspension obtained in Step 1 while stirring at room temperature to obtain a mixed solution of titanium alloy powder and alumina; the particle size of the titanium alloy powder is less than 100 μm, and the mass of alumina nanoparticles in the alumina nanoparticle suspension is 0.1% of the mass of titanium alloy powder.

[0033] Step 3: The mixture of titanium alloy powder and alumina obtained in Step 2 is stirred and evaporated in a water bath to obtain titanium alloy powder with pre-coated nano-alumina structure with core-shell structure.

[0034] Step 4: The pre-coated nano-alumina titanium alloy powder obtained in Step 3 is subjected to vacuum treatment to remove the dispersant, and then subjected to low-energy ball milling at a speed of 150 r / min to 300 r / min for 5 h to obtain alumina-titanium core-shell structure powder.

[0035] Step 5: The alumina-titanium core-shell structure powder obtained in Step 4 is subjected to high-current plasma activation vacuum hot pressing sintering at 800℃~1000℃ and sintering pressure of 20MPa~40MPa for 5 minutes to obtain a heterostructure titanium-based composite material.

[0036] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 543 MPa and an elongation of 22.5%.

[0037] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0038] The method for adjusting activity described in this embodiment can also be replaced by ball milling; the pre-coating treatment can also be replaced by low-energy ball milling.

[0039] Example 2

[0040] The difference between this embodiment and Embodiment 1 is that: in step one, the mass of the dispersant is 0.2% of the mass of the ethanol solution; in step two, the mass of the alumina nanoparticles in the alumina nanoparticle suspension is 0.3% of the mass of the titanium alloy powder.

[0041] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 659 MPa and an elongation of 17.4%.

[0042] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0043] Figure 1 Here is an electron microscope image of the alumina-titanium core-shell structured powder prepared in this embodiment. Figure 1 It can be seen that the highly active and highly porous nano-alumina in the alumina-titanium core-shell structure powder is uniformly coated on the surface of the titanium alloy powder. This uniform dispersion provides better conditions for reaction diffusion and precipitation.

[0044] Figure 2 The image shown is an electron microscope image of the heterostructured titanium alloy composite material prepared in this embodiment. Figure 2 It can be seen that a large number of fine precipitate particles appear at the grain boundaries and in some parts of the grain in this heterostructure titanium alloy composite material.

[0045] Example 3

[0046] The difference between this embodiment and Embodiment 1 is that: in step one, the mass of the dispersant is 0.2% of the mass of the ethanol solution; in step two, the mass of the alumina nanoparticles in the alumina nanoparticle suspension is 0.5% of the mass of the titanium alloy powder.

[0047] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 786 MPa and an elongation of 15.8%.

[0048] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0049] Example 4

[0050] The difference between this embodiment and Embodiment 1 is that: in step one, the mass of the dispersant is 0.3% of the mass of the ethanol solution; in step two, the mass of the alumina nanoparticles in the alumina nanoparticle suspension is 0.75% of the mass of the titanium alloy powder.

[0051] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 846 MPa and an elongation of 11.3%.

[0052] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 1 is that no alumina nanoparticles are added and there is no corresponding subsequent mixing step.

[0055] Figure 3 The tensile property curves are shown for the heterostructured titanium alloy composite materials prepared in Examples 1 to 4 of this invention and the titanium alloy material prepared in Comparative Example 1. Figure 3 It can be seen that the heterostructure titanium alloy composite materials prepared in Examples 1 to 4 of the present invention have significantly improved strength and good plasticity, achieving excellent strength-plasticity matching.

[0056] Example 5

[0057] The difference between this embodiment and Embodiment 1 is that: in step one, the mass of the dispersant is 0.3% of the mass of the ethanol solution; in step two, the mass of the alumina nanoparticles in the alumina nanoparticle suspension is 1.0% of the mass of the titanium alloy powder.

[0058] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment had a tensile strength of 980 MPa and an elongation of 5%.

[0059] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0060] Example 6

[0061] The difference between this embodiment and Embodiment 1 is that the mass of the dispersant in step one is 0.2% of the mass of the ethanol aqueous solution, the average particle size of the alumina is less than 15 nm, and the specific surface area is greater than 150 m². 2 / g; In step two, the mass of alumina nanoparticles in the alumina nanoparticle suspension is 0.25% of the mass of titanium alloy powder. The composition of titanium alloy powder is Al 6.45%, Mo 3.46%, Si 0.26%, Zr 1.7%, Fe 0.02%, O 0.11%, with the balance being Ti; In step five, the sintering temperature is 900℃~1100℃, and the sintering time is 10min.

[0062] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 1124 MPa and an elongation of 12.6%.

[0063] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 5 is that no alumina nanoparticles are added and there is no corresponding subsequent mixing step.

[0066] The titanium alloy material prepared in this comparative example was tested and found to have a tensile strength of 978 MPa and an elongation of 11.0%.

[0067] Figure 4 The tensile property curves are shown for the heterostructured titanium alloy composite materials prepared in Examples 5 and 6 of this invention and the titanium alloy material prepared in Comparative Example 2. Figure 4 It can be seen that the heterostructure titanium alloy composite materials prepared in Examples 5 to 6 of the present invention have good plasticity while improving strength, achieving excellent strength-plasticity matching.

[0068] Example 7

[0069] The difference between this embodiment and Embodiment 6 is that the mass of alumina nanoparticles in the alumina nanoparticle suspension in step two is 0.5% of the mass of titanium alloy powder.

[0070] Testing showed that the heterostructure titanium-based composite material prepared in this embodiment has a tensile strength of 1196 MPa and an elongation of 7.3%.

[0071] Testing revealed that the heterostructure in the heterostructure titanium matrix composite material prepared in this embodiment is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates, which are formed by the dissolution and diffusion of highly active γ-alumina nanoparticles into the inner titanium matrix and the precipitation of titanium-alumina-containing phases at the grain boundaries and dislocations of the titanium matrix on the shell.

[0072] 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 high-strength, high-plasticity heterostructure titanium-based composite material, characterized in that, The method includes the following steps: Step 1: The activity of the highly active alumina nanoparticles is adjusted, and then dispersed in an ethanol solution with the assistance of a dispersant to obtain an alumina nanoparticle suspension; the highly active alumina nanoparticles are highly active γ-structured alumina; the highly active alumina nanoparticles have a porous structure, an average particle size of less than 50 nm, and a specific surface area of ​​greater than 50 m². 2 / g, wherein the method for adjusting the activity is ultrasonic or ball milling treatment; Step 2: Add titanium alloy powder to the alumina nanoparticle suspension obtained in Step 1 while stirring at room temperature to obtain a mixed solution of titanium alloy powder and alumina. Step 3: Stir and evaporate the mixed solution of titanium alloy powder and alumina obtained in Step 2 under water bath conditions to obtain titanium alloy powder with pre-coated nano-alumina structure. Step 4: Vacuum treatment is performed on the pre-coated nano-alumina titanium alloy powder obtained in Step 3 to remove the dispersant, and then low-energy ball milling is performed to coat it to obtain nano-alumina-titanium core-shell structure powder. Step 5: The nano-alumina-titanium core-shell structure powder obtained in Step 4 is subjected to low-temperature short-time sintering to obtain a heterostructure titanium-based composite material; the low-temperature short-time sintering is high-current plasma activated vacuum hot pressing sintering, the sintering temperature is 800℃~1100℃, the holding time is less than 30min, and the sintering pressure is greater than 10MPa; the tensile strength of the heterostructure titanium-based composite material is 540MPa~1200MPa, and the elongation is 7%~23%.

2. The method for preparing a high-strength, plasticity-matched heterostructure titanium-based composite material according to claim 1, characterized in that, The dispersant mentioned in step one is polyethylene glycol and PVP, and the mass of the dispersant is less than 0.3% of the mass of the ethanol solution.

3. The method for preparing a high-strength, plasticity-matched heterostructure titanium-based composite material according to claim 1, characterized in that, The rotation speed used in step four, which involves low-energy ball milling coating, is less than 350 r / min.

4. The method for preparing a high-strength, plasticity-matched heterostructure titanium-based composite material according to claim 1, characterized in that, The heterostructure in the heterostructure titanium matrix composite material described in step five is a multi-level gradient distribution structure of titanium-aluminum oxide-containing precipitates that are dissolved and diffused into the inner titanium matrix by highly active γ-alumina nanoparticles, and precipitated on the shell to the titanium matrix grains, intragranular boundaries and dislocations.

5. A high-strength, high-plasticity heterostructure titanium-based composite material, characterized in that, Prepared by the method described in any one of claims 1 to 4.

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