A method for preparing a high-strength, heterogeneous titanium-based composite material

Abstract

This invention discloses a method for preparing a high-strength, ductile titanium-based composite material with a heterostructure. The method includes: 1. Selecting an α or (α+β) type titanium alloy as the matrix material, a metastable β type titanium alloy as the heterostructure material, and nano-sized carbon black and / or micron-sized TiB2 as the reinforcing material; 2. Mixing the matrix material, heterostructure material, and reinforcing material using ball milling; 3. Ion sintering; 4. Processing to obtain the high-strength, ductile titanium-based composite material with a heterostructure. This invention uses a metastable β type titanium alloy as the heterostructure material, providing partial elongation by adjusting the precipitation of the metastable phase to construct a heterostructure, and strengthening the α or (α+β) type titanium alloy matrix material. The reinforcing material further strengthens the composite material, collectively improving its strength. This achieves simultaneous improvement in both strength and ductility, and is low-cost, widely applicable, and suitable for large-scale industrial production.

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 heterogeneous structure. Background Technology

[0002] To meet the current demand for high-performance titanium alloys, researchers use titanium or titanium alloys as the matrix and add reinforcing phases such as graphene, carbon nanotubes, SiC, Ti5Si3, B4C, TiC, TiB2, and Al2O3. Powder metallurgy methods, combined with mechanical mixing and sintering, are used to prepare titanium-based composite materials with higher strength. Currently, introducing ceramic phases into titanium alloys to prepare titanium-based composite materials has become one of the most effective methods to further improve the performance of titanium alloys, showing broad prospects in aerospace, military, and marine engineering fields. Although the addition of reinforcing phases can improve the strength of composite materials to some extent, the main problem is its relatively low elongation. This stems from the inherent inverse relationship between strength and plasticity / toughness in metallic materials caused by classical dislocation motion theory. Therefore, it is urgent to break through the traditional design, preparation, and application concepts of titanium alloy structural materials guided by dislocation motion theory and explore new ways to enhance their strength, plasticity, and toughness.

[0003] By employing special processing techniques to construct coarse-grained and nano-fine-grained regions in the alloy, or by introducing dissimilar alloys with strengths intermediate between the matrix and the reinforcing phase, heterogeneous structures can be created. During plastic deformation of the composite material, these heterogeneous structures not only impede dislocations to a certain extent but also undergo plastic deformation themselves, alleviating dislocation pile-up and preventing premature fracture. This achieves both increased elongation and improved strength.

[0004] Titanium and titanium alloys are diverse, and can be classified into three categories based on their phase composition in the annealed state: α-type titanium alloys, (α+β)-type titanium alloys, and β-type titanium alloys. Among them, medium-strength (α+β)-type titanium alloys and high-strength β-type titanium alloys with heat-treatable controllable strength and plasticity can construct a heterogeneous structure of network (α+β) phase plus equiaxed β phase. By adjusting the strength of β-type titanium alloys through heat treatment, the inverse relationship between strength and plasticity in traditional structural materials can be broken, thereby achieving a simultaneous improvement in the strength and plasticity of composite materials.

[0005] Therefore, it is necessary to investigate a method to introduce β-type titanium alloy into α or (α+β)-type titanium alloys to construct heterostructures that simultaneously improve strength and ductility. Summary of the Invention

[0006] 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-ductility titanium-based composite material with a heterogeneous structure. This method uses a metastable β-type titanium alloy as the heterogeneous alloy material. By adjusting the precipitation of the metastable phase to construct the heterogeneous structure, partial ductility is provided, and the α or (α+β)-type titanium alloy matrix material is strengthened. The reinforcing material further strengthens the α or (α+β)-type titanium alloy matrix material, jointly improving the strength of the titanium-based composite material, thereby achieving a simultaneous improvement in both strength and ductility.

[0007] 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 heterogeneous structure, characterized in that the method includes the following steps:

[0008] Step 1, Material Selection: Select α or (α+β) type titanium alloy as the matrix material, select metastable β type titanium alloy as the hetero alloy material, and select nano-grade carbon black and / or micron-grade TiB2 as the reinforcing material.

[0009] Step 2, Powder Mixing: Place the powder of the matrix material selected in Step 1 and part of the powder of the reinforcing material in a ball mill and mix them evenly to obtain mixed powder A. Then, place the powder of the hetero-alloy material selected in Step 1 and the remaining powder of the reinforcing material in a ball mill and mix them evenly to obtain mixed powder B. Then, place mixed powder A and mixed powder B in a ball mill and mix them evenly to obtain mixed powder C.

[0010] Step 3, Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a titanium-based composite material blank;

[0011] Step 4, Hot processing: The titanium-based composite material blank obtained in Step 3 is subjected to hot rolling or hot extrusion deformation to obtain a high-strength PVC-based composite material with a heterogeneous structure; the tensile strength of the high-strength PVC-based composite material with a heterogeneous structure is increased by more than 25% compared with the matrix material, reaching 1400MPa to 1700MPa, and the elongation after fracture is comparable to that of the matrix material, reaching 9% to 17%.

[0012] This invention uses α or (α+β) type titanium alloy as the matrix material, metastable β type titanium alloy as the heterostructure material, and nano-sized carbon black and / or micron-sized TiB2 as the reinforcement material. A multi-stage ball milling method is employed: first, the matrix material powder and a portion of the reinforcement material powder are ball-milled and mixed; then, the heterostructure material powder and the remaining reinforcement material powder are ball-milled and mixed. The products from the two ball milling processes are then ball-milled and mixed again to promote thorough mixing of the components. Finally, the mixture is sintered and heat-treated sequentially to obtain a high-strength, ductile titanium-based composite material with a heterostructure. In the preparation of metastable β-type titanium alloys, an equiaxed body-centered cubic β phase is obtained after solution treatment and rapid cooling. This β phase exhibits higher plasticity than the close-packed hexagonal α phase. Based on this, this invention uses metastable β-type titanium alloys as heterojunction materials. By controlling the sintering and heat treatment processes of the mixed powders, including temperature and time, the lath-like close-packed hexagonal α phase and the equiaxed body-centered cubic β phase are controlled. The (α+β) phase microstructure of the matrix and the β phase precipitated during heat treatment are used to construct a heterostructure with significantly different grain sizes and mechanical properties, thereby improving… By providing partial ductility and simultaneously controlling the volume fraction of equiaxed β phase and lath-like α phase, the titanium alloy matrix is ​​strengthened. The reinforcing material, nano-sized carbon black, and the in-situ generated reinforcing phase TiC particles in TC4 titanium alloy, or the externally added reinforcing material, micron-sized TiB2, further strengthen the titanium alloy matrix, thus improving the strength of the titanium-based composite material. This achieves a simultaneous improvement in the strength and plasticity of the titanium-based composite material, breaking through the inverse relationship between strength and plasticity in traditional structural materials and solving the problem of poor strength-plasticity matching in titanium-based composite materials.

[0013] The method for preparing a high-strength, heterogeneous titanium-based composite material is characterized in that the α-type titanium alloy in step one is TA7 titanium alloy, and the (α+β)-type titanium alloy is TC4 titanium alloy. These titanium alloys are low-cost, easy to prepare, and have already been commercially applied.

[0014] The method for preparing a high-strength, heterogeneous titanium-based composite material is characterized in that the metastable β-type titanium alloy in step one is TC18, Ti1400, Ti-15Mo, or Ti-15Mo-2Fe titanium alloy. These titanium alloys are easy to prepare and low in cost, with corresponding Mo equivalents of 9, 11, 15, and 20, all falling between 9 and 20.

[0015] The method for preparing a high-strength, high-ductility titanium-based composite material with a heterogeneous structure, as described above, is characterized in that the Mo equivalent of the metastable β-type titanium alloy in step one is 9–20. Metastable β-type titanium alloys within this Mo equivalent range exhibit various phase transformations and deformation modes, making it easy to control the strength and ductility of the titanium-based composite material over a wide range through heat treatment.

[0016] The method for preparing a high-strength, heterogeneous titanium-based composite material is characterized in that, in step two, the mass ratio of the powder of the partial reinforcing material to the powder of the remaining reinforcing material is 1:1. This condition effectively promotes thorough mixing of the raw material powders.

[0017] The method for preparing a high-strength, high-plasticity titanium-based composite material with a heterostructure, as described above, is characterized in that, in step two, the mass content of the hetero-alloy material in the mixed powder C is 3%–40%, and the mass content of the reinforcing material is 0.5%–2.0%. By controlling the content of the hetero-alloy material, the improvement effect on the plasticity of the matrix titanium alloy is ensured, while avoiding excessive content that would seriously affect the strength of the titanium-based composite material; by controlling the content of the reinforcing material, the improvement effect on the plasticity of the matrix titanium alloy is ensured, while avoiding excessive content that would seriously deteriorate the plasticity of the titanium-based composite material and cause premature fracture.

[0018] The method for preparing a high-strength titanium-based composite material with a heterogeneous structure, as described above, is characterized in that the three ball milling processes in step two are performed at rotation speeds of 200 rpm to 300 rpm, with a ball-to-material ratio of 5:1 and a milling time of 7 to 10 hours. Low-energy ball milling is used for all three processes, which reduces heat generation while ensuring uniform mixing of the components and preventing severe oxidation of the mixed powder or even the introduction of impurities. Simultaneously, under these ball milling process parameters, the added reinforcing material powder particles are uniformly coated on the surface of the matrix material and the hetero-alloy material powder particles, which is beneficial for obtaining a core-shell structure titanium-based composite material preform after sintering, with the matrix or hetero-alloy as the core and TiC particles or TiB whiskers distributed on the shell.

[0019] The method for preparing a high-strength titanium-based composite material with a heterostructure, as described above, is characterized in that the plasma sintering temperature in step three is 900℃~1050℃, and the time is 5min. This invention sets the sintering temperature based on the β-phase transformation temperatures of the matrix alloy and the heterostructure alloy. While ensuring the density of the titanium-based composite material, the sintering temperature is controlled to be lower than the β-phase transformation temperature of the matrix alloy and higher than the β-phase transformation temperature of the heterostructure alloy. Furthermore, the short sintering time avoids grain growth, which is beneficial for ensuring the strength of the titanium-based composite material.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention uses metastable β-type titanium alloy as a heterostructure material. By adjusting the precipitation structure of the metastable phase, partial elongation is provided, and the α or (α+β) type titanium alloy matrix material is strengthened. The reinforcing material, nano-sized carbon black, and the in-situ generated reinforcing phase TiC particles in TC4 titanium alloy, along with the added micron-sized TiB2 reinforcing material, further strengthen the α or (α+β) type titanium alloy matrix material, jointly improving the strength of the titanium-based composite material. Thus, the strength and plasticity of the titanium-based composite material are improved simultaneously.

[0022] 2. The titanium-based composite material prepared by this invention consists of a body-centered cubic equiaxed β phase, a lath-shaped α phase or (α+β) phase, and TiC particles and TiB whiskers distributed on the core and shell. Through the coupling effect of various strengthening methods such as heterogeneous strengthening, multi-level multi-scale particle and whisker reinforcement, hot work hardening and solid solution strengthening, the mechanical properties of the titanium-based composite material are significantly enhanced.

[0023] 3. The titanium-based composite material prepared by this invention has excellent mechanical properties. Its tensile strength is more than 60% higher than that of the matrix material and more than 10% higher than that of titanium-based composite materials reinforced with TiC particles or TiB whiskers. Its elongation after fracture is comparable to that of the matrix material. It is a high-strength and high-elongation composite material.

[0024] 4. Compared with existing methods for constructing heterogeneous structures, this invention utilizes powder metallurgy to add dissimilar alloy powders to construct heterogeneous structures, thereby obtaining locally non-uniform titanium-based composite materials. The preparation method is simple, low-cost, and the structure and mechanical properties of the prepared titanium-based composite materials are controllable.

[0025] 5. The matrix material and heterojunction material powders selected in this invention can be prepared using the most common mass production 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-based composite materials. Moreover, the powders are widely available and have low cost. At the same time, the selected reinforcing phase materials, nano-sized carbon black powder or micron-sized TiB2 powder, are inexpensive and easy to obtain.

[0026] 6. The preparation process of this invention is low in cost, has a wide range of applications, is easy to implement, and the entire preparation process is short in time and low in energy consumption, making it suitable for large-scale industrial production. It also provides new ideas for the design and development of novel ultra-high strength metal matrix composites.

[0027] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0028] Example 1

[0029] This embodiment includes the following steps:

[0030] Step 1, Material Selection: (α+β) type TC4 titanium alloy is selected as the matrix material, Ti-15Mo titanium alloy is selected as the hetero alloy material, and micron-sized TiB2 is selected as the reinforcement material; the Mo equivalent of the Ti-15Mo titanium alloy is 15.

[0031] Step 2, Powder Mixing: 94.8g of (α+β) type TC4 titanium alloy powder with a particle size of 53μm selected in Step 1 and 0.6g of micron-sized TiB2 powder with a particle size of 5μm are placed in a ball mill and ball-milled to obtain mixed powder A. Then, 24g of Ti-15Mo titanium alloy powder with a particle size of 45μm selected in Step 1 and 0.6g of micron-sized TiB2 powder with a particle size of 5μm are placed in a ball mill and ball-milled to obtain mixed powder B. Mixed powder A and mixed powder B are then ball-milled to obtain mixed powder C. The ball milling speed for each of the three mixing processes is 200rpm, the ball-to-material ratio is 5:1, and the ball milling time is 7h.

[0032] Step 3: Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a TC4 titanium alloy composite material blank; the plasma sintering temperature is 1000℃, the time is 5min, and the pressure is 40MPa.

[0033] Step 4: Hot working: The TC4 titanium alloy composite material blank obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, a high-strength and high-ductility TC4 titanium alloy composite material with a heterogeneous structure is obtained.

[0034] According to the test results, the sintered yield strength of the TC4 titanium alloy composite material prepared in this embodiment is 1125.9 MPa, the tensile strength is 1234.4 MPa, and the elongation after fracture is 14.1%. The rolled yield strength is 1498.8 MPa, the tensile strength is 1599.6 MPa, and the elongation after fracture is 11.8%.

[0035] Comparative Example 1

[0036] This comparative example includes the following steps:

[0037] Step 1, Material Selection: (α+β) type TC4 titanium alloy is selected as the base material;

[0038] Step 2, Powder Mixing: Place 120g of (α+β) type TC4 titanium alloy powder with a particle size of 53μm selected in Step 1 into a ball mill and ball mill it to obtain mixed powder; the ball milling speed is 200rpm, the ball-to-material ratio is 5:1, and the ball milling time is 7h.

[0039] Step 3: Molding: The mixed powder obtained in Step 2 is subjected to plasma sintering to obtain a TC4 titanium alloy material blank; the plasma sintering temperature is 1000℃, the time is 5min, and the pressure is 40MPa.

[0040] Step 4: Hot working: The TC4 titanium alloy billet obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, the TC4 titanium alloy material is obtained.

[0041] The sintered yield strength of the TC4 titanium alloy material prepared in this comparative example was 864.4 MPa, the tensile strength was 988.1 MPa, and the elongation after fracture was 16.7%. The rolled yield strength was 1026.6 MPa, the tensile strength was 1215.8 MPa, and the elongation after fracture was 12.1%.

[0042] Comparing Example 1 of the present invention with Comparative Example 1, it can be seen that the TC4 titanium alloy composite material prepared by introducing heterostructure and reinforcing particles in the present invention has excellent mechanical properties. Its yield strength and tensile strength in the sintered state and after rolling are higher than those of TC4 titanium alloy, and its elongation after fracture in the sintered state and after rolling is comparable to that of TC4 titanium alloy. It is a high-strength and high-plasticity composite material.

[0043] Comparative Example 2

[0044] This comparative example includes the following steps:

[0045] Step 1, Material Selection: (α+β) type TC4 titanium alloy is selected as the matrix material, and nano-grade carbon black is selected as the reinforcing material;

[0046] Step 2, Powder Mixing: 120g of (α+β) type TC4 titanium alloy powder with a particle size of 53μm selected in Step 1 and 1.2g of nano-sized carbon black powder with a particle size of 20nm are placed in a ball mill and ball-milled to obtain a mixed powder; the ball milling speed is 200rpm, the ball-to-material ratio is 5:1, and the ball milling time is 7h.

[0047] Step 3: Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a TC4 titanium alloy composite material blank; the plasma sintering temperature is 1000℃, the time is 5min, and the pressure is 40MPa.

[0048] Step 4: Hot working: The TC4 titanium alloy composite material blank obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, a high-strength and high-ductility TC4 titanium alloy composite material is obtained.

[0049] The high-strength and high-performance TC4 titanium alloy composite material prepared in this comparative example has a sintered yield strength of 1123.4 MPa, a tensile strength of 1281.9 MPa, and an elongation after fracture of 15.5%. After rolling, the yield strength is 1331.6 MPa, the tensile strength is 1417.1 MPa, and the elongation after fracture is 12.1%.

[0050] Comparing Example 1 and Comparative Example 2, it can be seen that the TC4 titanium alloy composite material prepared by introducing heterostructure and reinforcing particles has excellent mechanical properties. Its yield strength and tensile strength in both the sintered state and after rolling are higher than those of the TC4 titanium alloy composite material without heterostructure. Its elongation after fracture in both the sintered state and after rolling is comparable to that of the TC4 titanium alloy composite material without heterostructure. It is a high-strength and high-plasticity composite material.

[0051] Example 2

[0052] This embodiment includes the following steps:

[0053] Step 1, Material Selection: α-type TA7 titanium alloy is selected as the matrix material, Ti1400 titanium alloy is selected as the hetero-alloy material, and nano-grade carbon black is selected as the reinforcing material; the Mo equivalent of the Ti1400 titanium alloy is 11.

[0054] Step 2, Powder Mixing: 115.8g of α-type TA7 titanium alloy powder with a particle size of 53μm selected in Step 1 and 0.3g of nano-sized carbon black powder with a particle size of 20nm are placed in a ball mill and ball-milled to obtain mixed powder A. Then, 3.6g of Ti1400 titanium alloy powder with a particle size of 45μm selected in Step 1 and 0.3g of nano-sized carbon black powder with a particle size of 20nm are placed in a ball mill and ball-milled to obtain mixed powder B. Mixed powder A and mixed powder B are then placed in a ball mill and ball-milled to obtain mixed powder C. The ball milling speed for each of the three mixing processes is 200rpm, the ball-to-material ratio is 5:1, and the ball milling time is 7h.

[0055] Step 3: Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a TA7 titanium alloy composite material blank; the plasma sintering temperature is 900℃, the time is 5min, and the pressure is 40MPa.

[0056] Step 4: Hot working: The TA7 titanium alloy composite material blank obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, a high-strength and high-ductility TA7 titanium alloy composite material with a heterogeneous structure is obtained.

[0057] According to the test results, the sintered yield strength of the TA7 titanium alloy composite material prepared in this embodiment is 1036.1 MPa, the tensile strength is 1148.1 MPa, and the elongation after fracture is 9.1%. The rolled yield strength is 1344.2 MPa, the tensile strength is 1511.8 MPa, and the elongation after fracture is 9.3%.

[0058] The deformation processing method in step four of this embodiment can be replaced by hot extrusion.

[0059] Example 3

[0060] This embodiment includes the following steps:

[0061] Step 1, Material Selection: (α+β) type TC4 titanium alloy is selected as the matrix material, TC18 titanium alloy is selected as the hetero alloy material, and nano-grade carbon black and micron-grade TiB2 are selected as the reinforcing materials; the Mo equivalent of the TC18 titanium alloy is 9.

[0062] Step 2, Powder Mixing: 82.2g of (α+β) type TC4 titanium alloy powder with a particle size of 53μm selected in Step 1 and 0.9g of nano-sized carbon black powder with a particle size of 20nm were placed in a ball mill and ball-milled to obtain mixed powder A. Then, 36g of TC18 titanium alloy powder with a particle size of 45μm selected in Step 1 and 0.9g of micron-sized TiB2 powder with a particle size of 5μm were placed in a ball mill and ball-milled to obtain mixed powder B. Mixed powder A and mixed powder B were then ball-milled to obtain mixed powder C. The ball milling speed for each of the three mixing processes was 300rpm, the ball-to-material ratio was 5:1, and the ball milling time was 10h.

[0063] Step 3: Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a TC4 titanium alloy composite material blank; the plasma sintering temperature is 1050℃, the time is 5min, and the pressure is 40MPa.

[0064] Step 4: Hot working: The TC4 titanium alloy composite material blank obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, a high-strength and high-ductility TC4 titanium alloy composite material with a heterogeneous structure is obtained.

[0065] According to the test results, the sintered yield strength of the TC4 titanium alloy composite material prepared in this embodiment is 1331.2 MPa, the tensile strength is 1232.8 MPa, and the elongation after fracture is 11.9%. The rolled yield strength is 1467.7 MPa, the tensile strength is 1577.1 MPa, and the elongation after fracture is 8.2%.

[0066] Example 4

[0067] This embodiment includes the following steps:

[0068] Step 1, Material Selection: (α+β) type TC4 titanium alloy is selected as the matrix material, Ti-15Mo-2Fe titanium alloy is selected as the hetero alloy material, and nano-grade carbon black and micron-grade TiB2 are selected as the reinforcing materials; the Mo equivalent of the Ti-15Mo-2Fe titanium alloy is 20.

[0069] Step 2, Powder Mixing: 111g of (α+β) type TC4 titanium alloy powder with a particle size of 53μm selected in Step 1 and 1.2g of nano-sized carbon black powder with a particle size of 20nm are placed in a ball mill and ball-milled to obtain mixed powder A. Then, 48g of Ti-15Mo-2Fe titanium alloy powder with a particle size of 45μm selected in Step 1 and 1.2g of micron-sized TiB2 powder with a particle size of 5μm are placed in a ball mill and ball-milled to obtain mixed powder B. Mixed powder A and mixed powder B are then ball-milled to obtain mixed powder C. The ball milling speed for each of the three mixing processes is 300rpm, the ball-to-material ratio is 5:1, and the ball milling time is 10h.

[0070] Step 3: Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a TC4 titanium alloy composite material blank; the plasma sintering temperature is 1050℃, the time is 5min, and the pressure is 40MPa.

[0071] Step 4: Hot working: The TC4 titanium alloy composite material blank obtained in Step 3 is hot rolled at 900℃ with a total deformation of 75%. After cooling in air, a high-strength and high-ductility TC4 titanium alloy composite material with a heterogeneous structure is obtained.

[0072] According to the test results, the sintered yield strength of the TC4 titanium alloy composite material prepared in this embodiment is 1242.2 MPa, the tensile strength is 1339.1 MPa, and the elongation after fracture is 10.9%. The rolled yield strength is 1553.7 MPa, the tensile strength is 1636.1 MPa, and the elongation after fracture is 9.2%.

[0073] 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, heterogeneous, titanium-based composite material, characterized in that, The method includes the following steps: Step 1, Material Selection: α or α+β type titanium alloy is selected as the matrix material, metastable β type titanium alloy is selected as the hetero alloy material, and nano-grade carbon black and / or micron-grade TiB2 is selected as the reinforcing material; the Mo equivalent of the metastable β type titanium alloy is 9~20. Step 2, Powder Mixing: The powder of the matrix material selected in Step 1 and a portion of the powder of the reinforcing material are placed in a ball mill and ball-milled to obtain mixed powder A. Then, the powder of the hetero-alloy material selected in Step 1 and the remaining powder of the reinforcing material are placed in a ball mill and ball-milled to obtain mixed powder B. Mixed powder A and mixed powder B are then placed in a ball mill and ball-milled to obtain mixed powder C. The ball milling speed for each of the three mixing steps is 200 rpm to 300 rpm, the ball-to-powder ratio is 5:1, and the ball milling time is 7 h to 10 h. The mass content of the hetero-alloy material powder in mixed powder C is 3% to 40%, and the mass content of the reinforcing material powder is 0.5% to 2.0%. Step 3, Molding: The mixed powder C obtained in Step 2 is subjected to plasma sintering to obtain a titanium-based composite material blank; the plasma sintering temperature is 900℃~1050℃ and the time is 5min. Step 4, Hot processing: The titanium-based composite material blank obtained in Step 3 is subjected to hot rolling or hot extrusion deformation to obtain a high-strength PVC-based composite material with a heterogeneous structure; the tensile strength of the high-strength PVC-based composite material with a heterogeneous structure is increased by more than 25% compared with the matrix material, reaching 1400MPa~1700MPa, and the elongation after fracture is comparable to that of the matrix material, reaching 9%~17%.

2. The method for preparing a high-strength, heterogeneous titanium-based composite material according to claim 1, characterized in that, In step one, the α-type titanium alloy is TA7 titanium alloy, and the α+β-type titanium alloy is TC4 titanium alloy.

3. The method for preparing a high-strength, heterogeneous titanium-based composite material according to claim 1, characterized in that, The metastable β-type titanium alloy mentioned in step one is TC18, Ti1400, Ti-15Mo or Ti-15Mo-2Fe titanium alloy.

4. The method for preparing a high-strength, heterogeneous titanium-based composite material according to claim 1, characterized in that, In step two, the mass ratio of the powder of the partial reinforcing material to the powder of the remaining reinforcing material is 1:1.