A method for preparing a high-strength and high-ductility titanium-based composite material with a composition gradient

Abstract

The application discloses a preparation method of high-strength and high-ductility titanium-based composite material with a composition gradient, and comprises the following steps: 1, material selection: selecting a plurality of Mo equivalent different beta type titanium alloy powder as a matrix material, and selecting carbon nanoparticles as a precursor material of a reinforcing body; 2, powder mixing: placing the plurality of Mo equivalent different beta type titanium alloy powder and the carbon nanoparticles in a ball mill and ball milling and uniformly mixing; 3, forming: performing plasma sintering forming on the mixed powder; 4, heat treatment: performing solid solution treatment on a titanium-based composite material blank to obtain the high-strength and high-ductility titanium-based composite material with the composition gradient. The application utilizes a powder metallurgy method to sinter the plurality of Mo equivalent different beta type titanium alloy powder and the carbon nanoparticles into a bulk alloy, so that the sintered bulk alloy has the composition gradient, and the prepared titanium-based composite material with the composition gradient has excellent mechanical properties and is a high-strength and high-elongation composite material.

Description

Technical Field

[0001] This invention belongs to the field of advanced structural materials technology, specifically relating to a method for preparing a high-strength titanium-based composite material with a compositional gradient. Background Technology

[0002] The development of advanced high-strength and high-ductility titanium alloys is increasingly becoming a major variable in the innovative development of my country's national security strategies and core sectors of the national economy, including land, sea, and air forces. Due to the urgent demand for high-performance titanium alloys in various fields, it is imperative to break the inherent inverse relationship between strength and ductility / toughness in metallic materials caused by classical dislocation motion theory, explore new ways to enhance and plasticize them, and develop high-performance titanium alloy structural materials. Based on the metastable phases and diverse deformation modes of β-type titanium alloys (body-centered cubic), this study utilizes multiphase transformation and multideformation modes (stress-induced α″ martensitic transformation, {332} <113> A novel titanium-based composite material with ultra-high strength and plasticity exhibiting multiple deformation modes was prepared by combining twinning, stress-induced ω-phase transformation, and dislocation slip. This not only meets practical needs but also helps to expand its application prospects in special engineering fields such as aerospace, weaponry, and deep-sea exploration.

[0003] The key to strengthening and toughening titanium-based composites lies in controlling the mechanical properties of the matrix material (titanium alloy). The various deformation modes mentioned above depend on the stability of the β phase in the β-type titanium alloy, which is generally quantitatively described using the Mo equivalent. With increasing Mo equivalent, the β-type titanium alloy will exhibit different deformation modes during plastic deformation, in the following order: stress-induced α″ martensitic transformation (Mo content between 9 and 14), {332} <113> Twin formation accompanied by stress-induced ω-phase transformation (Mo content between 15 and 23) and dislocation slip (Mo content greater than 23). Stress-induced α″ martensitic phase transformation and {332} <113> Twin formation can impart high elongation and significant work hardening effects to materials, but its yield strength is low. Stress-induced ω-phase transformation and dislocation slip can significantly increase the yield strength of materials, but at the cost of elongation. Therefore, relying solely on a single deformation mode with a single composition is insufficient to balance the strength and plasticity of a material. Introducing multi-composition microregions within the material and utilizing the synergistic effect of multiple deformation modes to strengthen and plasticize the material is a promising new material design method to overcome this contradiction. Titanium alloys are typically prepared using a melting method, which can obtain titanium alloys with homogeneous composition and microstructure at a relatively low cost. However, the materials prepared by this method have a homogeneous composition and coarse microstructure, making them unsuitable for preparing titanium alloys with gradient compositions or their composites. Therefore, a new method for preparing high-strength and high-plasticity titanium-based composites with gradient compositions needs to be investigated. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing a high-strength, high-efficiency titanium-based composite material with a compositional gradient. This method utilizes powder metallurgy to sinter various β-type titanium alloy powders with different Mo equivalents and carbon nanoparticles into a bulk alloy, resulting in a compositional gradient in the sintered bulk alloy. The prepared titanium-based composite material with a compositional gradient exhibits excellent mechanical properties, with a tensile strength between 1100 MPa and 1300 MPa and an elongation between 10% and 20%. This represents a strength increase of up to 99% compared to single-component β-type titanium alloys, and also demonstrates excellent elongation, making it a high-strength, high-elongation composite material.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a high-strength titanium-based composite material with a compositional gradient, characterized in that the method includes the following steps:

[0006] Step 1, Material Selection: Select various β-type titanium alloy powders with different Mo equivalents as matrix materials and carbon nanoparticles as precursor materials for reinforcement.

[0007] Step 2, Powder Mixing: Place the various β-type titanium alloy powders with different Mo equivalents and carbon nanoparticles selected in Step 1 into a ball mill and mix them evenly to obtain a mixed powder;

[0008] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering to obtain a titanium-based composite material blank;

[0009] Step 4, heat treatment: The titanium-based composite material blank obtained in Step 3 is subjected to solution treatment to obtain a high-strength ductile titanium-based composite material with compositional gradient; the tensile strength of the high-strength ductile titanium-based composite material with compositional gradient is 1100MPa~1300MPa, and the elongation after fracture is 10%~20%.

[0010] This invention utilizes powder metallurgy to sinter various β-type titanium alloy powders with different Mo equivalents and carbon nanoparticles into bulk alloys, so that the sintered bulk alloys have a compositional gradient.

[0011] This invention adds carbon nanoparticles, which are uniformly coated on the surface of the matrix alloy powder during ball milling. During sintering, they react in situ with the titanium elements in the matrix to generate TiC particles, forming a discontinuous three-dimensional network structure inside the composite material. In addition to increasing strength, the introduction of TiC mainly plays a role in grain refinement. Due to the high sintering temperature, the titanium alloy matrix grains will become larger and reduce strength. However, the three-dimensional network structure of TiC can significantly hinder grain boundary movement, thereby inhibiting grain growth.

[0012] This invention involves sintering various β-type titanium alloy powders with different Mo equivalents. This sintering creates localized compositional variations (Mo equivalent variations) within the material, termed compositional gradients. Under stress loading, the β-phase in the high Mo equivalent region exhibits higher stability, not only avoiding plastic deformation itself but also limiting stress-induced α″ martensitic transformation and {332} in the low Mo equivalent region. <113> Twining, which in turn increases the yield strength of the material, during plastic deformation, the phase transformation and twinning in the low Mo equivalent region and the stress-induced ω phase transformation in the high Mo equivalent region can all provide additional plastic deformation, and the stress-induced α″ martensitic phase transformation and {332} <113> Twins can also refine grains, giving the material a certain work hardening effect and further increasing the tensile strength of the material. Therefore, titanium-based composite materials with compositional gradients can simultaneously improve their strength and plasticity, breaking through the inverse relationship between strength and plasticity in traditional structural materials and solving the problem of poor strength-plasticity matching.

[0013] The above-mentioned method for preparing a high-strength, high-performance titanium-based composite material with a compositional gradient is characterized in that the various β-type titanium alloy powders with different Mo equivalents mentioned in step one are β-type titanium alloy powders with a Mo equivalent of 9-14, β-type titanium alloy powders with a Mo equivalent of 15-23, and β-type titanium alloy powders with a Mo equivalent greater than 23. In this invention, the three ranges of Mo equivalent correspond to the following deformation modes: stress-induced α″ martensitic transformation, {332} <113> Twins, accompanied by stress-induced ω-phase transformation and dislocation slip, are combined to improve the tensile strength and plasticity of high-strength titanium-based composite materials with compositional gradients. By controlling the particle size of β-type titanium alloy powder, finer matrix powder particle size is conducive to the formation of fine grains, thereby increasing strength and plasticity. Spherical powder has good flowability and high density after sintering. By controlling the particle size of carbon nanoparticles, nanoscale carbon nanoparticles are conducive to uniform adhesion to the surface of matrix powder, and the formed TiC particles are fine and do not agglomerate.

[0014] The above-mentioned method for preparing a high-strength, high-performance titanium-based composite material with a compositional gradient is characterized in that, in step two, the mass ratio of β-type titanium alloy powder with a Mo equivalent of 9-14, β-type titanium alloy powder with a Mo equivalent of 15-23, and β-type titanium alloy powder with a Mo equivalent greater than 23 in the mixed powder is 1:1:(1-3), and the mass content of carbon nanoparticles in the mixed powder is 0.3%-0.5%. In this invention, the proportion of high Mo equivalent regions within the material is crucial for ensuring strength; a too low proportion will cause stress-induced α″ martensitic transformation and {332} <113> Twin formation occurs preferentially, reducing strength. If the proportion is too high, the low Mo equivalent region will lose its function and worsen the elongation of the material. The mass content of the reinforcing material powder is 0.3% to 0.5%. If the content is too low, it will promote grain boundary movement, leading to grain growth and reducing mechanical properties. If the content is too high, it will form a continuous three-dimensional network structure, which will seriously reduce the connectivity of the material matrix, hinder plastic deformation, and cause the material to fracture prematurely, thus reducing the elongation.

[0015] The above-mentioned method for preparing a high-strength titanium-based composite material with a compositional gradient is characterized in that the ball milling speed in step two is 180 rpm to 250 rpm. This invention, by controlling the ball milling parameters to a lower milling capacity, ensures uniform powder mixing while maintaining good sphericity, which is beneficial for improving the density of the sintered material. Too low a speed, ball-to-powder ratio, or milling time will result in uneven powder mixing and agglomeration of precursor powder, severely affecting the mechanical properties of the sintered material. Too high a speed, ball-to-powder ratio, or milling time will severely damage the sphericity of the powder, reducing the density and mechanical properties of the material.

[0016] The above-mentioned method for preparing a high-strength titanium-based composite material with a compositional gradient is characterized in that the solution treatment temperature in step four is 900℃~1100℃, and the cooling method is water cooling. In this invention, due to the low cooling rate of spark plasma sintering, an α phase inevitably forms inside the material. To obtain a supersaturated β phase, a solution treatment needs to be performed above the β phase transition point. Depending on the composition, the β phase transition point is between 800℃ and 900℃. Therefore, a solution treatment is performed between 900℃ and 1100℃. Excessively high solution treatment temperatures will cause severe grain growth inside the composite material, significantly reducing the material's strength.

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

[0018] 1. This invention utilizes powder metallurgy to sinter various β-type titanium alloy powders with different Mo equivalents and carbon nanoparticles into a bulk alloy, resulting in a compositional gradient in the sintered bulk alloy. The prepared titanium-based composite material with compositional gradient exhibits excellent mechanical properties, with a tensile strength between 1100 MPa and 1300 MPa and an elongation between 10% and 20%. Compared with a single-component β-type titanium alloy, the strength is increased by up to 99%, and it also has excellent elongation, making it a high-strength, high-elongation composite material.

[0019] 2. This invention utilizes powder metallurgy to add alloy powders of different compositions to construct a compositional gradient. The preparation method is simple, the cost is low, and the structure and mechanical properties of the resulting composite material are controllable.

[0020] 3. The β-type titanium alloy powders with different compositions selected in this invention can all be prepared using the most common industrial preparation method—the rotating electrode method. The alloy powders prepared by this method have carbon, hydrogen, and nitrogen impurity contents of less than 10 ppm and oxygen content of less than 100 ppm, which is beneficial to improving the quality of titanium alloy composite materials. Moreover, the powders are widely available and have low cost. At the same time, the carbon nanoparticles selected are inexpensive and easy to obtain.

[0021] 4. The preparation process of the present invention has low cost, wide application range, and is easy to implement. The entire preparation process is short in time and low in energy consumption, making it suitable for large-scale industrial production.

[0022] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0023] Example 1

[0024] This embodiment includes the following steps:

[0025] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and a particle size of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0026] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0027] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0028] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0029] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1188 MPa and an elongation after fracture of 17%, as tested.

[0030] Comparative Example 1

[0031] This comparative example includes the following steps:

[0032] Step 1, Material Selection: β-type titanium alloy powder with a Mo equivalent of 9 and a particle size of 15μm to 53μm is selected as the matrix material, and carbon nanoparticles with a particle size of 20nm are selected as the precursor material for the reinforcement.

[0033] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder; the mass content of carbon nanoparticles in the mixed powder is 0.5%;

[0034] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0035] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour, and then water-cooled to obtain a titanium-based composite material.

[0036] The titanium-based composite material prepared in this embodiment has a tensile strength of 653 MPa and an elongation after fracture of 59%, as tested.

[0037] Comparative Example 2

[0038] This comparative example includes the following steps:

[0039] Step 1, Material Selection: β-type titanium alloy powder with a Mo equivalent of 15 and a particle size of 15μm to 53μm is selected as the matrix material, and carbon nanoparticles with a particle size of 20nm are selected as the precursor material for the reinforcement.

[0040] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder; the mass content of carbon nanoparticles in the mixed powder is 0.5%;

[0041] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0042] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour, and then water-cooled to obtain a titanium-based composite material.

[0043] According to the test results, the tensile strength of the titanium-based composite material with cultural relic composition gradient prepared in this embodiment is 812 MPa, and the elongation after fracture is 49%.

[0044] Comparative Example 3

[0045] This comparative example includes the following steps:

[0046] Step 1, Material Selection: β-type titanium alloy powder with a Mo equivalent of 24 and a particle size of 15μm to 53μm is selected as the matrix material, and carbon nanoparticles with a particle size of 20nm are selected as the precursor material for the reinforcement.

[0047] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder; the mass content of carbon nanoparticles in the mixed powder is 0.5%;

[0048] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0049] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour, and then water-cooled to obtain a titanium-based composite material.

[0050] According to the test results, the tensile strength of the titanium-based composite material with cultural relic composition gradient prepared in this embodiment is 846 MPa, and the elongation after fracture is 24%.

[0051] By comparing Comparative Examples 1, 2, and 3 with Example 1, it can be seen that the titanium-based composite material without compositional gradient prepared by using only one type of Mo equivalent β-type titanium alloy powder and carbon nanoparticles has lower tensile strength and higher elongation after fracture.

[0052] Example 2

[0053] This embodiment includes the following steps:

[0054] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and a particle size of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0055] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:3, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0056] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0057] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0058] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1227 MPa and an elongation after fracture of 11%, as tested.

[0059] Example 3

[0060] This embodiment includes the following steps:

[0061] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and a particle size of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0062] Step 2, Powder Mixing: The β-type titanium alloy powder selected in Step 1 and carbon nanoparticles are placed in a ball mill and ball-milled for 7 hours at a speed of 250 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0063] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0064] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0065] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1167 MPa and an elongation after fracture of 17%, as tested.

[0066] Example 4

[0067] This embodiment includes the following steps:

[0068] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and particle sizes of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0069] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0070] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0071] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 1100℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0072] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1100 MPa and an elongation after fracture of 20% as tested.

[0073] Example 5

[0074] This embodiment includes the following steps:

[0075] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 14, 23 and 25 and particle sizes of 15μm to 53μm is selected as the matrix material, and carbon nanoparticles with a particle size of 20nm are selected as the precursor material for the reinforcement.

[0076] Step 2, Powder Mixing: The β-type titanium alloy powder selected in Step 1 and carbon nanoparticles are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 14, 23 and 25 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0077] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0078] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0079] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1300 MPa and an elongation after fracture of 10%.

[0080] Example 6

[0081] This embodiment includes the following steps:

[0082] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and a particle size of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0083] Step 2, Powder Mixing: The β-type titanium alloy powder selected in Step 1 and carbon nanoparticles are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.3%.

[0084] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0085] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0086] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1108 MPa and an elongation after fracture of 19%, as tested.

[0087] Example 7

[0088] This embodiment includes the following steps:

[0089] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 and a particle size of 15μm to 53μm was selected as the matrix material, and carbon nanoparticles with a particle size of 20nm were selected as the precursor material for the reinforcement.

[0090] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 180 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 9, 15 and 24 in the mixed powder is 1:1:1, and the mass content of carbon nanoparticles in the mixed powder is 0.4%.

[0091] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0092] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 900℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0093] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1144 MPa and an elongation after fracture of 19%, as tested.

[0094] Example 8

[0095] This embodiment includes the following steps:

[0096] Step 1, Material Selection: β-type titanium alloy powder with Mo equivalents of 12, 18 and 25 and a particle size of 15μm to 53μm is selected as the matrix material, and carbon nanoparticles with a particle size of 20nm are selected as the precursor material for the reinforcement.

[0097] Step 2, Powder Mixing: The β-type titanium alloy powder and carbon nanoparticles selected in Step 1 are placed in a ball mill and ball-milled for 7 hours at a speed of 200 rpm and a ball-to-powder ratio of 5:1 to obtain a mixed powder. The mass ratio of β-type titanium alloy powder with Mo equivalents of 12, 18 and 25 in the mixed powder is 1:1:2, and the mass content of carbon nanoparticles in the mixed powder is 0.5%.

[0098] Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering at a pressure of 40 MPa and a temperature of 1000℃ for 5 minutes to obtain a titanium-based composite material blank.

[0099] Step 4, heat treatment: The titanium-based composite material blank obtained in step 3 is kept at 1000℃ for 1 hour and then water-cooled to obtain a high-strength ductile titanium-based composite material with compositional gradient.

[0100] The titanium-based composite material with compositional gradient prepared in this embodiment has a tensile strength of 1221 MPa and an elongation after fracture of 9%.

[0101] 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 technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength, titanium-based composite material with a compositional gradient, characterized in that, The method includes the following steps: Step 1, Material Selection: Select various β-type titanium alloy powders with different Mo equivalents as matrix materials and carbon nanoparticles as precursor materials for reinforcement; the various β-type titanium alloy powders with different Mo equivalents are β-type titanium alloy powders with Mo equivalents of 9~14, β-type titanium alloy powders with Mo equivalents of 15~23, and β-type titanium alloy powders with Mo equivalents greater than 23. Step 2, Powder Mixing: Place the various β-type titanium alloy powders with different Mo equivalents and carbon nanoparticles selected in Step 1 into a ball mill and mix them evenly to obtain a mixed powder; Step 3, Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering to obtain a titanium-based composite material blank; Step 4, heat treatment: The titanium-based composite material blank obtained in Step 3 is subjected to solution treatment to obtain a high-strength ductile titanium-based composite material with compositional gradient; the tensile strength of the high-strength ductile titanium-based composite material with compositional gradient is 1100MPa~1300MPa, and the elongation after fracture is 10%~20%.

2. The method for preparing a high-strength, titanium-based composite material with a compositional gradient according to claim 1, characterized in that, In step two, the mass ratio of β-type titanium alloy powder with a Mo equivalent of 9-14, β-type titanium alloy powder with a Mo equivalent of 15-23, and β-type titanium alloy powder with a Mo equivalent greater than 23 in the mixed powder is 1:1:(1-3), and the mass content of carbon nanoparticles in the mixed powder is 0.3%-0.5%.

3. The method for preparing a high-strength, titanium-based composite material with a compositional gradient according to claim 1, characterized in that, The ball milling speed in step two is 180 rpm to 250 rpm.

4. The method for preparing a high-strength, titanium-based composite material with a compositional gradient according to claim 1, characterized in that, The solution treatment in step four is carried out at a temperature of 900℃~1100℃, and the cooling method is water cooling.