A multiscale heterogeneous high-strength plastic titanium-based composite material and a preparation method thereof
By constructing a multi-scale heterogeneous structure in titanium-based composites and utilizing TiC reinforcing phase and β phase transformation to excite dislocations, the problem of the inversion of strength and plasticity in titanium-based composites was solved, achieving a balance between high strength and good plasticity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN UNIV
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
Smart Images
Figure CN122303682A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of titanium alloy technology, and more specifically, to a multi-scale heterogeneous titanium-based composite material and its preparation method. Background Technology
[0002] Titanium-based composites, due to their high specific strength, excellent corrosion resistance, and high-temperature performance, show broad application prospects in aerospace, advanced weapon systems, and the automotive industry. Currently, the strengthening methods for these materials mainly rely on the introduction of high-modulus, high-hardness ceramic reinforcing phases, such as TiC, TiB, and SiC. These reinforcing phases are typically generated through in-situ self-generation technology by adding carbon, boron, or silicon sources to the titanium alloy matrix. Their strengthening mechanisms mainly include grain refinement strengthening—inhibiting grain growth by pinning grain boundaries with reinforcing phases; dispersion strengthening—nano or submicron-sized particles hindering dislocation movement; and load transfer—external forces are transferred from the relatively soft titanium alloy matrix to the high-strength reinforcing phase through the interface.
[0003] However, this traditional strengthening method inevitably brings the technical challenge of a "strength-plasticity inversion." During application, when the material is subjected to external loads, due to significant differences in physical properties between the ceramic reinforcing phase and the titanium alloy matrix, such as a mismatch in elastic modulus and coefficient of thermal expansion, stress tends to concentrate highly at the interface between the reinforcing phase and the matrix, leading to crack formation and premature material failure. Therefore, although the strength of the material is significantly improved, its elongation often drops sharply, greatly sacrificing plasticity and damage tolerance. This has become a major bottleneck restricting the further engineering applications of titanium-based composite materials.
[0004] Heterogeneous materials are material systems composed of soft and hard regions with significantly different mechanical properties (such as hardness and strength), and with good bonding interfaces between these regions. In this microstructure, the soft phase provides plastic deformation capacity to accommodate strain, while the hard phase ensures the material's load-bearing capacity. This allows the material to achieve high strength while maintaining excellent work hardening ability and plasticity, avoiding premature necking. Currently, this concept has been successfully verified in layered metal composites, bimodal grain structure alloys, and gradient structure materials, achieving a good match between strength and plasticity. However, in the field of titanium-based composites, how to construct heterogeneous structures by introducing reinforcing phases through reasonable composition design and process control, so that the material maintains good plasticity while achieving high strength, remains a technical problem that urgently needs in-depth research. Summary of the Invention
[0005] The technical problem this invention aims to solve is to address the shortcomings of the prior art by proposing a multi-scale heterogeneous titanium-based composite material and its preparation method. This method constructs a multi-scale heterogeneous structure in the titanium-based composite material by adding a multi-component carbide ceramic reinforcing phase and combining it with a β-stabilizing element-induced diffusion-induced local β-phase transformation. This not only achieves direct strengthening through the ceramic reinforcing phase, but more importantly, utilizes the β-phase transformation-induced heterogeneous structure to induce the generation of geometrically necessary dislocations and back stress hardening effects during deformation. This effectively alleviates stress concentration at the reinforcing phase / matrix interface, delays crack initiation and propagation, and ultimately improves the elongation of the material while maintaining high strength.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A multi-scale heterogeneous high-strength ductile titanium matrix composite material includes a pure α-phase titanium matrix, an α+β biphase induced by element diffusion of the titanium matrix and TiC reinforcing phase, and a TiC reinforcing phase.
[0008] Preferably, the titanium-based composite material has a tensile strength of 1020-1055 MPa and an elongation after fracture of 14-18%.
[0009] A multi-scale heterogeneous high-strength plastic titanium-based composite material and its preparation method, comprising the following steps:
[0010] (1) Pure titanium powder and (TaTiV)C multi-component carbide ceramic nanopowder were ball-milled and mixed to obtain titanium-based composite powder with (TaTiV)C powder encapsulating pure titanium.
[0011] (2) The titanium-based composite powder obtained in (1) is subjected to plasma sintering to obtain a sintered titanium-based composite material;
[0012] (3) The sintered titanium-based composite material obtained in (2) is subjected to hot rolling to obtain a hot-rolled titanium-based composite material.
[0013] Preferably, in step (1), the pure titanium powder is a spherical particle with a particle size of 15-53 μm, and the added (TaTiV)C ceramic nanoparticles account for 2-7.5 wt% of the total mass of the composite powder.
[0014] Preferably, (TaTiV)C ceramic nanoparticles account for 2-5 wt% of the total mass of the composite powder.
[0015] Preferably, the preparation method of (TaTiV)C ceramic nanopowder includes: weighing and ball milling Ta2O5, TiO2, V2O5 and carbon powder in an equiatomic ratio; pressing the obtained mixed powder into a compact, and then performing carbothermic reduction to synthesize single-phase carbide ceramic; finally crushing by ball milling to obtain nanoscale (TaTiV)C ceramic powder.
[0016] Preferably, in step (1), the mass ratio of ball to material in the ball milling mixture is 3:1 to 6:1, the ball milling speed is 140 r / min to 200 r / min, the forward rotation is 3 min to 30 min, the reverse rotation is 3 min to 30 min, the forward and reverse rotations are paused for 3 to 10 min in between, and the total ball milling time is 5 to 10 h.
[0017] Preferably, in step (2), the plasma sintering process is as follows: the pressure is 20-40 MPa, the sintering temperature is 800-1000℃, and the holding time is 5-15 min.
[0018] Preferably, in step (3), the hot rolling process is as follows: the hot rolling temperature is 750-1000℃, the deformation per pass is 5-20%, the tempering temperature between passes is 750-1000℃, and the total rolling deformation is 50-80%.
[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0020] This invention addresses the strength-plasticity inversion relationship in titanium-based composites. While maintaining the high modulus of ceramics, it utilizes the high-temperature decomposition and multi-component diffusion characteristics of (TaTiV)C to achieve dual regulation: on one hand, Ti atoms in the matrix diffuse into the ceramic region and combine with C, forming a TiC reinforcing phase in situ; on the other hand, Ta and V elements in (TaTiV)C diffuse locally into the titanium matrix, undergoing phase transformation. This synergistic process is expected to construct a multi-scale heterogeneous structure composed of the TiC reinforcing phase, a diffusion-induced α+β dual-phase region, and a pure α-phase region in the matrix. This not only enables load transfer strengthening through the TiC reinforcing phase, but more importantly, it utilizes the multi-scale heterogeneous structure to induce the generation of geometrically necessary dislocations and back stress hardening during deformation, thereby effectively alleviating stress concentration, delaying crack initiation and propagation, and ultimately improving elongation while maintaining high strength. Attached Figure Description
[0021] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:
[0022] Figure 1 The figure shows the characterization results of the nanoscale (TaTiV)C powder in the preparation example; Where a is the XRD pattern and b is the SEM image.
[0023] Figure 2 The image shows the SEM image of the 800℃ hot-rolled titanium-based composite material with a (TaTiV)C addition of 5wt% in Example 1.
[0024] Figure 3The image shows the SEM image of the titanium-based composite material heat-treated at 1000℃ with 5wt% (TaTiV)C in Comparative Example 3.
[0025] Figure 4 The stretching curves are for Examples 1, 2, and Comparative Examples 1, 2, and 3. Detailed Implementation
[0026] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways than those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
[0028] It should be noted that the raw materials, instruments, etc. involved in this invention are all commercially available products.
[0029] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.
[0030] Preparation example: (TaTiV)C nanopowder
[0031] The raw materials consist of V2O5 (99.9% purity), Ta2O5 (99.9% purity), TiO2 (99.9% purity) with particle sizes of 500nm~1μm and carbon powder with particle sizes of 1~3μm. Except for a small amount of unavoidable impurity elements, the raw materials do not contain other metallic impurity elements. According to the method of equal atomic ratio of components and total powder weight of 50g, 8.88g of V2O5 powder, 21.58g of Ta2O5 powder, 7.80g of TiO2 powder, and 11.74g of carbon powder are weighed. The weighed powders are placed in a cemented carbide ball mill jar for wet mixing. The ball-to-powder mass ratio is 4:1. The ball milling medium is 100ml of anhydrous ethanol. The ball milling speed is 250r / min, with 60min of forward rotation and 60min of reverse rotation, without interruption between forward and reverse rotation. The total ball milling time is 20h. The mixed powder after ball milling needs to be dried at 90℃ for 10h. The dried mixed powder was pressed into cylindrical compacts using a hydraulic press at a pressure of 40 MPa. The compacts were then placed in a carbothermic reduction furnace, and the vacuum level inside the furnace was reduced to 6 Pa using a mechanical pump. Carbothermic reduction was then performed at a heating rate of 10 °C / min, reaching 1000 °C and holding for 1 hour, followed by further heating to 1950 °C and holding for 1 hour, and then cooling to room temperature to obtain single-phase carbide (TaTiV)C powder. The obtained powder was placed in a cemented carbide ball mill jar and crushed in a horizontal ball mill with a ball-to-powder mass ratio of 4:1, a milling speed of 113 r / min, and a total milling time of 10 hours to obtain nanoscale powder. Its XRD pattern and powder morphology are shown below. Figure 1 As shown.
[0032] Example 1
[0033] 28.5g of pure titanium powder with a particle size of 15-53μm and 1.5g of nano-sized (TaTiV)C ceramic powder were weighed at a mass ratio of 95:5 and a total powder weight of 30g. The weighed powders were placed in a stainless steel ball mill jar for dry mixing. The grinding balls were agate balls with a random particle size distribution, the ball-to-powder ratio was 4:1, and the rotation speed was set to 150 r / min. The ball milling process adopted an alternating forward and reverse rotation mode: first forward rotation for 5 minutes, pause for 5 minutes, then reverse rotation for 5 minutes, and so on, for a total ball milling time of 8 hours. The entire ball milling process was carried out under an inert argon atmosphere to obtain the final composite powder. The obtained composite powder was subjected to spark plasma sintering at a sintering temperature of 800℃, a pressure of 30MPa, and a holding time of 10 minutes to prepare the sintered titanium-based composite material. The sintered block was then hot-rolled at 800°C, with a deformation of 10% per pass and a tempering temperature of 800°C between passes, resulting in a total deformation of 70%.
[0034] like Figure 2As shown, microstructural observation revealed a multi-scale heterogeneous structure within the material, consisting of an in-situ generated TiC reinforcing phase, a diffusion-induced two-phase region, and a pure α-phase matrix. Mechanical property testing showed a yield strength of 973.46 MPa, a tensile strength of 1055.94 MPa, and an elongation after fracture of 17.8%, exhibiting excellent strength-ductility balance (see...). Figure 4 ).
[0035] The aforementioned superior mechanical properties are primarily attributed to the successful construction of a multi-scale heterogeneous microstructure within the material. The dispersed TiC reinforcing phase plays a significant role in dislocation pinning during deformation, effectively enhancing the material's strength. The alternating hard and soft phases, with their interwoven scales, effectively stimulate back stress strengthening during plastic deformation. This not only significantly increases the work hardening rate and delays necking, but also provides additional strengthening contributions. Consequently, the material achieves high strength while maintaining excellent plasticity, realizing a good balance between strength and toughness.
[0036] Example 2
[0037] 29.4g of pure titanium powder with a particle size of 15-53μm and 0.6g of nanoscale (TaTiV)C ceramic powder were weighed at a mass ratio of 98:2 and a total powder weight of 30g. The weighed powders were placed in a stainless steel ball mill jar for dry mixing. The grinding balls were agate balls with a random particle size distribution, the ball-to-powder ratio was 4:1, and the rotation speed was set to 150 r / min. The ball milling process adopted an alternating forward and reverse rotation mode: first forward rotation for 5 minutes, pause for 5 minutes, then reverse rotation for 5 minutes, and so on, for a total ball milling time of 8 hours. The entire ball milling process was carried out under an inert argon atmosphere, and the final composite powder was obtained. The obtained composite powder was subjected to spark plasma sintering at a sintering temperature of 800℃, a pressure of 30MPa, and a holding time of 10 minutes to prepare a sintered titanium-based composite material. The sintered block was then hot-rolled at 800°C, with a deformation of 10% per pass and a tempering temperature of 800°C between passes, resulting in a total deformation of 70%. This resulted in a multi-scale heterogeneous structure similar to that in Example 1. Mechanical property tests showed a yield strength of 959.77 MPa, a tensile strength of 1023.51 MPa, and an elongation after fracture of 14.86% (tensile curves are shown in...). Figure 4 However, due to the low amount of (TaTiV)C added, the number of in-situ generated TiC reinforcing phases is reduced, and the area ratio of heterogeneous structures is lowered, resulting in a weakening of the TiC reinforcing effect and back stress strengthening effect, thus causing the strength and plasticity of the material to decrease slightly compared with Example 1.
[0038] Example 3
[0039] The powder was prepared in a mass ratio of 92.5:7.5 and a total powder weight of 30g, with the rest being the same as in Example 1.
[0040] Comparative Example 1
[0041] The only difference from Example 1 is that the amount of (TaTiV)C added is increased to 10 wt%. All other operations and conditions are exactly the same as in Example 1.
[0042] A similar multi-scale heterogeneous structure was also formed within the material. Mechanical property testing showed a yield strength of 961.78 MPa and a tensile strength of 1055.35 MPa, essentially the same as in Example 1 (973.46 MPa, 1055.94 MPa), but the elongation after fracture was only 8.22% (tensile curve shown). Figure 4 The content of TiC was significantly lower than that of Example 1 (17.8%). This is mainly attributed to the increased amount of (TaTiV)C added, which led to an increase in the amount of TiC-reinforcing phase generated and an increase in the area ratio of the α+β dual-phase region. Although more TiC enhances the dislocation hindering effect and is beneficial to improving strength, it also causes severe dislocation pile-up at TiC sites, inducing premature initiation and rapid propagation of microcracks, resulting in a significant reduction in the material's plasticity.
[0043] Comparative Example 2
[0044] The only difference from Example 1 is that the hot rolling temperature and the inter-pass tempering temperature are 900°C. All other operations and conditions are exactly the same as in Example 1.
[0045] A similar multi-scale heterogeneous structure was also formed within the material. Mechanical property testing showed that the yield strength of the titanium-based composite material in this comparative example was 994.86 MPa, the tensile strength was 1026.94 MPa, and the elongation after fracture was only 4.75% (tensile curves are shown in...). Figure 4 Compared to Example 1, the yield strength was slightly improved, the tensile strength was slightly reduced, but the plasticity decreased sharply. The main reason is that the increased hot rolling temperature led to coarsening of the TiC reinforcing phase particles, while the diffusion of Ta and V elements was more complete, causing the two-phase region to almost completely transform into the β phase. Although the material still possesses a multi-scale heterogeneous structure and back stress strengthening effect, the coarsened TiC and β phase interface is prone to severe stress concentration, promoting the premature initiation and rapid propagation of microcracks, thus causing a significant reduction in the material's plasticity.
[0046] Comparative Example 3
[0047] The only difference from Example 1 is that a heat treatment process is used instead of hot rolling. The specific process parameters are: holding at 1000°C for 60 minutes, followed by air cooling, to obtain the heat-treated titanium-based composite material. All other operations and conditions are exactly the same as in Example 1.
[0048] Microstructural observation revealed that the material exhibited only a single-scale heterogeneous structure, with the matrix consisting solely of an α+β dual-phase titanium alloy, lacking the multi-scale heterogeneous structure found in Example 1. Furthermore, the TiC reinforcing phase particles displayed a near-continuous network distribution (see...). Figure 3 After mechanical property testing, the yield strength of the titanium-based composite material in this comparative example was 660.26 MPa, the tensile strength was 789.35 MPa, and the elongation after fracture was only 12.52% (see...). Figure 4 Compared to Example 1, both strength and plasticity decreased significantly. The main reason is that heat treatment led to microstructural evolution. The higher temperature (1000℃) and longer holding time allowed Ta and V elements to fully diffuse into the matrix, forming an α+β dual-phase titanium alloy. The material lost its multi-scale heterogeneous characteristics, the back stress strengthening effect weakened, and the strength decreased. At the same time, under these conditions, the TiC reinforcing phase coarsens, causing severe stress concentration, which led to a decrease in plasticity.
[0049] Table 1. Performance comparison of titanium-based alloys in the examples and comparative examples in sintered and hot-rolled states.
[0050]
[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A multi-scale heterogeneous high-strength plastic titanium-based composite material, characterized in that, It includes a pure α-phase titanium matrix, an α+β dual phase induced by elemental diffusion between a titanium matrix and a TiC-reinforced phase, and a TiC-reinforced phase.
2. The multi-scale heterogeneous high-strength PVC-Titanium matrix composite material according to claim 1, characterized in that, The titanium-based composite material has a tensile strength of 1020-1055 MPa and an elongation after fracture of 14-18%.
3. The method for preparing a multi-scale heterogeneous high-strength PVC-based composite material according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Pure titanium powder and (TaTiV)C multi-component carbide ceramic nanopowder were ball-milled and mixed to obtain titanium-based composite powder with (TaTiV)C powder encapsulating pure titanium. (2) The titanium-based composite powder obtained in (1) is subjected to plasma sintering to obtain a sintered titanium-based composite material; (3) The sintered titanium-based composite material obtained in (2) is subjected to hot rolling to obtain a hot-rolled titanium-based composite material.
4. The preparation method according to claim 3, characterized in that, In step (1), the pure titanium powder is a spherical particle with a particle size of 15-53 μm, and the added (TaTiV)C ceramic nanoparticles account for 2-7.5 wt% of the total mass of the composite powder.
5. The preparation method according to claim 4, characterized in that, The preparation method of (TaTiV)C ceramic nanopowder includes: weighing Ta2O5, TiO2, V2O5 and carbon powder in an equiatomic ratio, and mixing them by ball milling; pressing the obtained mixed powder into a compact, and then performing carbothermic reduction to synthesize single-phase carbide ceramics; finally, crushing by ball milling to obtain nanoscale (TaTiV)C powder.
6. The preparation method according to claim 3, characterized in that, In step (1), the mass ratio of ball material to material in the ball milling mixture is 3:1 to 6:1, the ball milling speed is 140 r / min to 200 r / min, the forward rotation is 3 min to 30 min, the reverse rotation is 3 min to 30 min, the forward and reverse rotations are paused for 3 to 10 min in between, and the total ball milling time is 5 to 10 h.
7. The preparation method according to claim 3, characterized in that, In step (2), the plasma sintering process is as follows: the pressure is 20-40 MPa, the sintering temperature is 800-1000℃, and the holding time is 5-15 min.
8. The preparation method according to claim 3, characterized in that, In step (3), the hot rolling process is as follows: the hot rolling temperature is 750-1000℃, the deformation per pass is 5-20%, the tempering temperature between passes is 750-1000℃, and the total rolling deformation is 50-80%.