阅读说明：本技术 一种Ti-V-Mo-Zr-Cr-Al系高强亚稳β钛合金及其制备方法 (Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy and preparation method thereof ) 是由 张金钰 杨家坤 包翔云 刘刚 孙军 于 2020-10-28 设计创作，主要内容包括：本发明公开了一种Ti-V-Mo-Zr-Cr-Al系高强亚稳β钛合金及其制备方法,将Ti-V-Mo-Zr-Cr-Al系亚稳β钛合金经过熔炼、热轧以及固溶时效处理后,可获得高强度同时具有一定塑性的高强钛合金。其中,Ti-V-Mo-Zr-Cr-Al系钛合金按重量百分比计,包括4.0～8.0％的V,5.0～8.5％的Mo,0.5～1.5％的Zr以及1.5～4.0％的Cr,5.0～6.0％的Al,余量为Ti。本发明合金本发明的钛合金具有突出的力学性能,固溶态下,抗拉强度可达到769～855MPa,延伸率达到4.3～15.9％。固溶时效后,抗拉强度可达1350～1471MPa,并且具有一定的强度塑性匹配,延伸率达到2.9～7.2％。(The invention discloses a Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy and a preparation method thereof. Wherein the Ti-V-Mo-Zr-Cr-Al titanium alloy comprises, by weight, 4.0-8.0% of V, 5.0-8.5% of Mo, 0.5-1.5% of Zr, 1.5-4.0% of Cr, 5.0-6.0% of Al, and the balance Ti. The titanium alloy has outstanding mechanical properties, and in a solid solution state, the tensile strength can reach 769-855MPa, and the elongation rate reaches 4.3-15.9%. After solid solution and aging, the tensile strength can reach 1350-1471 MPa, certain strength and plasticity matching is realized, and the elongation reaches 2.9-7.2%.)

1. A Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy is characterized by comprising, by weight, 4.0-8.0% of V, 5.0-8.5% of Mo, 0.5-1.5% of Zr and 1.5-4.0% of Cr, 5.0-6.0% of Al, and the balance Ti and inevitable impurity elements.

2. The Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy according to claim 1, wherein V, Mo, Zr, Cr, Al and Ti are high-purity vanadium, high-purity molybdenum, high-purity zirconium, high-purity chromium, high-purity aluminum and high-purity titanium, respectively.

3. The Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy according to claim 1 or 2, wherein the Mo equivalent is in the range of 7.5-11.

4. A method for preparing a Ti-V-Mo-Zr-Cr-Al series high strength metastable beta titanium alloy according to any of claims 1-3, characterized by comprising the following steps:

step 1, uniformly mixing the raw materials according to the weight percentage, smelting for many times in an argon atmosphere, and cooling to obtain an ingot;

step 2, homogenizing the obtained cast ingot;

step 3, rolling the ingot subjected to materialization treatment in a temperature interval of a two-phase zone, wherein the total deformation amount of rolling is 80-86%;

and 4, carrying out heat treatment on the rolled cast ingot in a temperature range of a two-phase region to obtain the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy.

5. The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy according to claim 4, characterized in that in the step 1, induction suspension smelting is adopted, the induction current in the smelting process is 400-600A, the current frequency is 20-25 KHz, the alloy is kept for 3-5 min after being completely melted, and the alloy is cooled to obtain an ingot, wherein the smelting frequency is not less than 5 times.

6. The method for preparing Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy according to claim 4, characterized in that the homogenizing treatment in the step 2 is performed at 1000 ℃ for 1 h.

7. The method for preparing Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy according to claim 4, characterized in that the temperature range of the dual-phase zone is 780-800 ℃.

8. The method for preparing Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy as claimed in claim 4, wherein in the rolling process, the temperature of the furnace is raised to the temperature range of the two-phase region after each rolling pass and is kept for about 2-5min, and the deformation of each rolling pass is about 5-15%.

9. The method for preparing Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy according to claim 4, characterized in that the step 4 heat treatment comprises solution treatment and aging treatment.

10. The method for preparing the Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy according to the claim 9, characterized in that the solution treatment is performed for 1h at the dual-phase region of 780-800 ℃, and the solution is cooled to room temperature;

and the aging treatment is to perform aging treatment on the cast ingot at 550 ℃ for 8h, and air-cool the cast ingot to room temperature.

Technical Field

The invention belongs to the technical field of high-performance alloy materials, and particularly relates to a Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy and a preparation method thereof.

Background

Titanium and titanium alloys have excellent mechanical and physical properties including high specific strength, low elastic modulus, high fatigue resistance, high toughness, excellent corrosion resistance, good formability and excellent biocompatibility, and are widely used in the fields of aerospace, energy industry, petrochemical industry, biomedicine and the like. For high-strength titanium alloys Ti1023, Ti5553, Ti55531 and the like, the yield strength of the alloys after aging is generally about 1200-1300 MPa, and the forgings of the alloys are successfully applied to key parts of aircraft undercarriages, connecting rods and the like.

Generally, the types of high-strength and high-toughness titanium alloys mainly comprise near-beta titanium alloys and metastable-beta titanium alloys, the Mo equivalent is generally between 7 and 15, and the alloys have the performance characteristics of alpha + beta two-phase and beta-phase alloys, namely, the alloys have good cold processing performance, good strength, plasticity and toughness comprehensive mechanical properties in a solid solution state, and are very excellent in hot processing performance and high in hardenability. However, with increasingly harsh service conditions, the strength of the existing titanium alloy material is increasingly difficult to meet the service requirements of the new generation of high-strength titanium alloy. Particularly, the tensile strength of the existing ultrahigh-strength titanium alloy is 1300MPa grade and is not more than 1400MPa under the condition of keeping good plasticity. Therefore, the development of titanium alloy with high strength and good plastic deformation capability is a critical problem to be solved.

Disclosure of Invention

Aiming at the problem that the existing titanium alloy cannot meet the use requirement, the invention provides a novel high-strength metastable beta titanium alloy of Ti-V-Mo-Zr-Cr-Al series and a preparation method thereof, wherein the tensile strength of the novel high-strength metastable beta titanium alloy reaches 1350-1471 MPa.

The invention is realized by the following technical scheme:

a Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy comprises, by weight, 4.0-8.0% of V, 5.0-8.5% of Mo, 0.5-1.5% of Zr, 1.5-4.0% of Cr, 5.0-6.0% of Al, and the balance Ti and inevitable impurity elements.

Preferably, the V, the Mo, the Zr, the Cr, the Al and the Ti are respectively high-purity vanadium, high-purity molybdenum, high-purity zirconium, high-purity chromium, high-purity aluminum and high-purity titanium.

Preferably, the Mo equivalent is in the range of 7.5-11.

A preparation method of Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

step 1, uniformly mixing the raw materials according to the weight percentage, smelting for many times in an argon atmosphere, and cooling to obtain an ingot;

step 2, homogenizing the obtained cast ingot;

and 3, rolling the ingot subjected to conversion treatment in a temperature interval of a two-phase zone, wherein the total deformation amount of rolling is 80-86%.

And 4, carrying out heat treatment on the rolled cast ingot in a temperature range of a two-phase region to obtain the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy.

Preferably, in the step 1, induction suspension smelting is adopted, the induction current in the smelting process is 400-600A, the current frequency is 20-25 KHz, the alloy is kept for 3-5 min after being completely melted, and the ingot is obtained by cooling, wherein the smelting frequency is not less than 5 times.

Preferably, the homogenization treatment in step 2 is carried out at a high temperature of 1000 ℃ for 1 hour.

Preferably, the temperature range of the two-phase zone is 780-800 ℃.

Preferably, in the rolling process, after each pass of rolling, the furnace returns to the temperature range of the two-phase region and is heated for about 2-5min, and the deformation of each pass is about 5-15%.

Preferably, the step 4 heat treatment comprises solution treatment and aging treatment.

Preferably, the solid solution treatment is carried out for 1h at the temperature of 780-800 ℃ in a dual-phase region, and water cooling is carried out to room temperature;

and the aging treatment is to perform aging treatment on the cast ingot at 550 ℃ for 8h, and air-cool the cast ingot to room temperature.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a novel high-strength metastable beta titanium alloy of Ti-V-Mo-Zr-Cr-Al series, wherein the Mo content element is higher and is not less than 5.0 percent by mass. The Mo element has slow diffusion speed in the titanium alloy, inhibits coarsening of an alpha phase, enables the size of a precipitated phase in the titanium alloy to be small, further enables the titanium alloy to have better heat treatment strengthening effect, refines beta sub-crystalline grains, can inhibit the ordering tendency of Fe and Cr in the alloy, avoids plasticity loss caused by brittle intermetallic compounds, and has higher solid solution strengthening effect compared with V. V is not less than 4.0% by mass. The solid solubility of the V element in the alpha phase is higher than that of Mo, so that the alpha phase can be solid-solution strengthened, the c/a value of the alpha phase is reduced, the slippage of the alpha phase is facilitated, and the titanium alloy has lower rheological resistance and good plasticity. The content of Al is 5.0-6.0% by mass. The Al element is beneficial to the precipitation of a secondary alpha phase and the formation of an omega phase, the solid solution strengthening effect is not obvious when the content is too low, the phase change point is possibly caused to be lower, the development of a thermal deformation process is not facilitated, and the ordering tendency is generated when the content is too high, so that the fracture toughness of the material is harmed. Meanwhile, a certain amount of neutral element Zr is added to strengthen the alpha phase, and dislocation slip critical slitting stress in the alpha phase is increased, so that the overall strength of the alloy is improved. A certain amount of Cr mainly plays a role in solid solution strengthening, and improves the plasticity, toughness and hardenability of the material.

The novel metastable beta titanium alloy has outstanding mechanical property, the tensile strength can reach 769-855MPa in a solid solution state, and the elongation rate reaches 4.3-15.9%. After solid solution and aging, the tensile strength can reach 1350-1471 MPa, certain strength and plasticity matching is realized, and the elongation reaches 2.9-7.2%.

The preparation method of the novel high-strength metastable beta titanium alloy of the Ti-V-Mo-Zr-Cr-Al series is simple and easy, the elements are uniformly mixed according to the mass percent, the mixture is smelted for a plurality of times in the argon atmosphere, and is cooled to obtain the cast ingot, the cast ingot is homogenized at high temperature, hot rolling is carried out in a two-phase region, water cooling is carried out to the room temperature after rolling is finished, and then heat treatment processes including solid solution and aging treatment are carried out. The rolling and the subsequent solution treatment are carried out in a dual-phase region of 780-800 ℃, the temperature is relatively moderate, energy is saved, the rolling temperature and the solution treatment temperature are the same, the rolling and the solution treatment can be carried out in heating equipment at the same time, and the energy, the time cost and the equipment cost are further saved while the performance is kept stable and consistent.

Drawings

FIG. 1 is a microstructure of a high strength metastable beta titanium alloy of example 1 of the present invention;

FIG. 2 is a microstructure of a high strength metastable beta titanium alloy of example 2 of the present invention;

FIG. 3 is a microstructure of a high strength metastable beta titanium alloy of example 3 of the present invention;

FIG. 4 is a microstructure of a high strength metastable beta titanium alloy of example 4 of the present invention;

FIG. 5 is a graph showing tensile properties of a Ti-V-Mo-Zr-Cr-Al system metastable beta titanium alloy after solid Solution (ST) and aging (STA) according to the present invention.

Detailed Description

The present invention will now be described in further detail with reference to the attached drawings, which are illustrative, but not limiting, of the present invention.

A Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following components in percentage by weight: 4.0 to 8.0% of V, 5.0 to 8.5% of Mo, 0.5 to 1.5% of Zr and 1.5 to 4.0% of Cr, 5.0 to 6.0% of Al, and the balance Ti and inevitable impurity elements.

The range of the Mo equivalent is 7.5-11, the index is used for measuring the stability of the beta phase and belongs to the range of metastable beta titanium alloy or near beta titanium alloy, and the phase transition temperature T is 820-850 ℃.

The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

step 1, uniformly mixing the raw materials according to the weight percentage, putting the raw materials into a furnace in bulk, then carrying out cold crucible induction suspension smelting, and cooling to obtain an ingot.

Argon is introduced in the smelting process, the induced current is 400-600A, the current frequency is 20-25 KHz, the alloy is kept for 3-5 min after being completely melted, and the ingot is obtained by cooling, wherein the smelting frequency is not less than 5.

The raw materials for smelting the alloy comprise: high purity titanium, high purity vanadium, high purity molybdenum, high purity aluminum, high purity zirconium, and high purity chromium.

And 2, homogenizing the obtained cast ingot at the high temperature of 1000 ℃ for 1h, and then cooling the cast ingot to room temperature by water.

And 3, rolling at the dual-phase region of 780-800 ℃, returning and preserving heat for about 2min after each pass of rolling, wherein the deformation of each pass is about 5-15%, and the final deformation is 80-86%.

Step 4, the subsequent heat treatment process specifically comprises the following steps: carrying out solution treatment for 1h at the temperature of 780-800 ℃ in a dual-phase region, cooling the solution to room temperature by water, then carrying out aging treatment for 8h at the temperature of 550 ℃, and cooling the solution to room temperature by air to obtain the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy.

According to the requirement of the GB/T228.1-2010 standard, the mechanical properties of the novel high-strength metastable beta titanium alloy of the Ti-V-Mo-Zr-Cr-Al series are measured as follows: tensile strength R in solid solution_mIs 769-855MPa, yield strength R_p0.2680 and 830MPa, total elongation at break A_t4.34 to 15.9 percent. After solution aging, tensile strength R_m1360 and 1471MPa, yield strength R_p0.21321.5-1415.3MPa, total elongation at break A_t2.9-7.2%, so that the titanium alloy has excellent strength and certain plasticity.

Example 1

The Ti-V-Mo-Zr-Cr-Al series novel high-strength metastable beta titanium alloy comprises the following components in percentage by weight: v4%, Mo 8.5%, Zr 1%, Cr 2.5%, Al 5.5%, and the balance Ti and unavoidable impurities.

The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

(1) the raw materials for smelting the alloy comprise: the method comprises the following steps of uniformly mixing raw materials of high-purity titanium, high-purity vanadium, high-purity molybdenum, high-purity aluminum, high-purity zirconium and high-purity chromium according to a ratio, putting the raw materials into a furnace in bulk, then carrying out cold crucible induction suspension smelting, introducing argon gas in the smelting process, introducing an induction current of 400A and keeping the current frequency of 20KHz for 3min after the alloy is completely molten, cooling to obtain an ingot, and smelting for 5 times.

(2) Homogenizing the cast ingot at 1000 ℃ for 1h, and then cooling to room temperature by water.

(3) Rolling the ingot subjected to homogenization treatment at 800 ℃ in a dual-phase region, returning and keeping the temperature for about 2min after each rolling, wherein the deformation of each pass is about 5 percent, and the final deformation is 84.58 percent.

(4) Carrying out heat treatment on the rolled cast ingot, wherein the process specifically comprises the following steps: carrying out solution treatment for 1h at 800 ℃ in a two-phase region, cooling to room temperature by water, then carrying out aging for 8h at 550 ℃, and cooling in air.

In the Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy of the embodiment, the transformation temperature T is about 845 +/-5 ℃, the obtained structure is shown in FIG. 1, and the microstructure of the titanium alloy of the embodiment contains a spherical or short rod-shaped primary alpha phase, the size is about 5-10 μm, and a large amount of fine nano-scale needle-like secondary alpha phases. The primary alpha phase is soft and is beneficial to the plasticity of the alloy, while the secondary alpha phase is taken as a second phase to strengthen and block dislocation movement, so that the alloy has excellent strength, and in addition, a certain amount of continuous alpha phase is also arranged at a grain boundary, thus having adverse effect on the plasticity of the alloy.

After the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy is subjected to hot rolling, the alloy is subjected to solution treatment and aging treatment, and the mechanical properties of the alloy are measured according to the GB/T228.1-2010 standard requirements as follows: tensile strength R in solid solution_m849MPa, yield strength R_p0.2775MPa, total elongation at break A_tThe content was 15.9%. After solution aging, tensile strength R_m1471MPa, yield strength R_p0.21415.3MPa, total elongation at break A_t2.9 percent, and has excellent strength and certain plasticity.

Example 2

The Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following components in percentage by weight: v5%, Mo 6%, Zr 1%, Cr 4%, Al 5%, and the balance Ti and inevitable impurities.

The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

(1) the raw materials for smelting the alloy comprise: the method comprises the following steps of uniformly mixing raw materials of high-purity titanium, high-purity vanadium, high-purity molybdenum, high-purity aluminum, high-purity zirconium and high-purity chromium according to a ratio, putting the raw materials into a furnace in bulk, then carrying out cold crucible induction suspension smelting, introducing argon gas in the smelting process, introducing an induction current of 500A and a current frequency of 22KHz, continuously keeping for 4min after the alloy is completely molten, cooling to obtain an ingot, and smelting for 8 times.

(2) Homogenizing the cast ingot at the high temperature of 1000 ℃ for 1h, and then cooling the cast ingot to room temperature by water;

(3) rolling the ingot subjected to homogenization treatment at a dual-phase region of 790 ℃, returning and keeping the temperature for about 2min after each rolling, wherein the deformation of each pass is about 8 percent, and the final deformation is 84.38 percent;

(4) carrying out heat treatment on the rolled cast ingot, wherein the process specifically comprises the following steps: performing solution treatment for 1h at the temperature of 790 ℃ in a two-phase region, cooling the solution to room temperature by water, then performing aging treatment for 8h at 550 ℃, and cooling the solution by air.

The Ti-V-Mo-Zr-Cr-Al series novel high-strength metastable beta titanium alloy has the phase transition temperature T of about 825 +/-5 ℃, the obtained structure is shown in figure 2, and the titanium alloy microstructure of the embodiment contains a spherical or short rod-shaped primary alpha phase, the size of about 5-10 mu m and a large amount of fine nano needle-like secondary alpha phases. The primary alpha phase is soft and is beneficial to the plasticity of the alloy, and the secondary alpha phase is taken as a second phase to strengthen and block dislocation movement, so that the alloy has excellent strength. In addition, a certain amount of continuous alpha phase is present at the grain boundaries, which has an adverse effect on the alloy plasticity.

In this embodiment, the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy is hot-rolled, then subjected to solution treatment and aging treatment, and measured according to the requirements of the GB/T228.1-2010 standard, has the following mechanical properties: tensile strength R in solid solution_m826MPa, yield strength R_p0.2789MPa, total elongation at break A_tThe content was 10.8%. After solution aging, tensile strength R_m1411MPa, yield strength R_p0.21348.7MPa, total elongation at break A_t4.5 percent, and has excellent strength and certain plasticity.

Example 3

The Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following components in percentage by weight: v6%, Mo 6.5%, Zr 0.5%, Cr 2%, Al 5%, and the balance Ti and unavoidable impurities.

The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

(1) the raw materials for smelting the alloy comprise: the method comprises the following steps of uniformly mixing raw materials of high-purity titanium, high-purity vanadium, high-purity molybdenum, high-purity aluminum, high-purity zirconium and high-purity chromium according to a ratio, putting the raw materials into a furnace in bulk, then carrying out cold crucible induction suspension smelting, introducing argon gas in the smelting process, introducing an induction current of 600A and a current frequency of 25KHz, continuously keeping for 5min after the alloy is completely molten, cooling to obtain an ingot, and smelting for 6 times.

(2) Homogenizing the cast ingot at 1000 ℃ for 1h, and then cooling to room temperature by water.

(3) Rolling the ingot subjected to homogenization treatment at a dual-phase region of 790 ℃, returning and keeping the temperature for about 2min after each rolling, wherein the deformation of each pass is about 15 percent, and the final deformation is 85.11 percent;

(4) the process for heat treatment of the rolled cast ingot comprises the following specific steps: performing solution treatment for 1h at the temperature of 790 ℃ in a two-phase region, cooling the solution to room temperature by water, then performing aging for 8h at 550 ℃, and cooling the solution to room temperature by air.

In the Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy of the embodiment, the transformation temperature T is about 835 +/-5 ℃, the obtained structure is shown in FIG. 3, and the microstructure of the titanium alloy of the embodiment contains more spherical or short rod-shaped primary alpha phases, the size is about 5-10 μm, and a large amount of fine nano-scale acicular secondary alpha phases. The primary alpha phase is soft and is beneficial to the plasticity of the alloy, and the secondary alpha phase is taken as a second phase to strengthen and block dislocation movement, so that the alloy has excellent strength. In addition, there is also more continuous alpha phase at the grain boundaries, which has an adverse effect on alloy plasticity.

In the embodiment, the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy is subjected to solution treatment and aging treatment after hot rolling, and the mechanical properties of the alloy are measured according to the GB/T228.1-2010 standard requirements as follows: tensile strength R in solid solution_m855MPa, yield strength R_p0.2At 830MPa, fractureTotal elongation A_tThe content was 4.34%. After solution aging, tensile strength R_m1360MPa, yield strength R_p0.21321.9MPa, total elongation at break A_t5.2 percent, and has excellent strength and certain plasticity.

Example 4

The Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following components in percentage by weight: v8%, Mo 5%, Zr 1.5%, Cr 1.5%, Al 5%, and the balance Ti and unavoidable impurities.

The preparation method of the Ti-V-Mo-Zr-Cr-Al series high-strength metastable beta titanium alloy comprises the following steps:

(1) the raw materials for smelting the alloy comprise: the method comprises the following steps of uniformly mixing raw materials of high-purity titanium, high-purity vanadium, high-purity molybdenum, high-purity aluminum, high-purity zirconium and high-purity chromium according to a ratio, putting the raw materials into a furnace in bulk, then carrying out cold crucible induction suspension smelting, introducing argon gas in the smelting process, introducing an induction current of 550A and keeping the current frequency of 25KHz for 3.5min after the alloy is completely molten, cooling to obtain an ingot, and smelting for 10 times.

(2) Homogenizing the cast ingot at the high temperature of 1000 ℃ for 1h, and then cooling the cast ingot to room temperature by water;

(3) rolling the ingot subjected to homogenization treatment at the dual-phase region of 780 ℃, returning and keeping the temperature for about 2min after each pass of rolling, wherein the deformation of each pass is about 10 percent, and the final deformation is 81.46 percent.

(4) Carrying out heat treatment on the rolled cast ingot, wherein the process specifically comprises the following steps: carrying out solution treatment for 1h at the temperature of a dual-phase region of 780 ℃, cooling the solution to room temperature by water, then carrying out aging for 8h at the temperature of 550 ℃, and cooling the solution to room temperature by air.

The transformation temperature T of the Ti-V-Mo-Zr-Cr-Al high-strength metastable beta titanium alloy is about 825 +/-5 ℃ in the embodiment, the obtained structure is shown in FIG. 4, the microstructure of the titanium alloy in the embodiment contains a small amount of spherical or short rod-shaped primary alpha phase, the size is about 5-10 μm, and a large amount of fine nanometer needle-shaped secondary alpha phase. The primary alpha phase is soft and is beneficial to the plasticity of the alloy, and the secondary alpha phase is taken as a second phase to strengthen and block dislocation movement, so that the alloy has excellent strength. In addition, continuous grain boundary alpha phase is not seen in the figure, so the alloy of the embodiment has higher plasticity.

After hot rolling, the novel high-strength metastable beta titanium alloy of Ti-V-Mo-Zr-Cr-Al series of the embodiment is subjected to solution treatment and aging treatment, and the mechanical properties of the alloy are measured according to the GB/T228.1-2010 standard requirements as follows: tensile strength R in solid solution_m769MPa, yield strength R_p0.2680MPa, total elongation at break A_tIt was 10.69%. After solution aging, tensile strength R_m1383MPa, yield strength R_p0.21321.5MPa, total elongation at break A_t7.2 percent, and has excellent strength and certain plasticity.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.