CN114657417A

CN114657417A - High-strength plastic titanium alloy suitable for cold deformation processing and preparation method thereof

Info

Publication number: CN114657417A
Application number: CN202210491419.6A
Authority: CN
Inventors: 肖文龙; 任磊; 付雨; 马朝利
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2022-05-07
Filing date: 2022-05-07
Publication date: 2022-06-24
Anticipated expiration: 2042-05-07
Also published as: CN114657417B

Abstract

The invention discloses a high-strength plastic titanium alloy suitable for cold deformation processing and a preparation method thereof, and the high-strength plastic titanium alloy comprises the following components in percentage by mass: 3.5 to 4.5 percent of Mo, 2.5 to 3.5 percent of Cr, 0.7 to 1.5 percent of Fe, 0.35 percent of O and the balance of Ti; the preparation method comprises the following steps: proportioning raw materials, and preparing a titanium alloy ingot by vacuum melting; performing hot processing at 1150-720 ℃; performing solid solution treatment at 790-730 ℃ to obtain a finished product of the high-strength plastic titanium alloy, or further performing aging treatment at 430-530 ℃ to obtain a finished product of the high-strength plastic titanium alloy, or performing cold rolling and aging heat treatment after heat treatment to obtain the finished product of the high-strength plastic titanium alloy. According to the invention, strong beta stabilizing elements such as Mo, Cr and Fe are added, the alpha stabilizing element is not added to improve the plastic deformation capacity of the alpha phase at room temperature and high temperature, the contents of the alpha phase and the beta phase and the element distribution are regulated and controlled through thermal mechanical treatment, the cold deformation processing performance, the strength and the plastic matching of the titanium alloy are improved, and the titanium alloy has the characteristics of low cost, easiness in cold processing and excellent strong plastic matching.

Description

High-strength plastic titanium alloy suitable for cold deformation processing and preparation method thereof

Technical Field

The invention belongs to the technical field of titanium alloy materials, and particularly relates to a high-strength plastic titanium alloy suitable for cold deformation processing and a preparation method thereof.

Background

The titanium alloy has the advantages of small density, high specific strength, corrosion resistance, no magnetism and the like, and is widely applied to the fields of aerospace, petrochemical engineering, ocean engineering, weaponry and the like as a structural material. At present, alpha + beta two-phase titanium alloys are the titanium alloy type with the largest use amount, but the strength of the alloys is usually lower than 1000MPa, such as TC4, TA15 and the like, and cold deformation processing is difficult. After solution aging heat treatment, metastable beta titanium alloys can obtain higher strength, such as TB5, TB6, Ti-15-3, Ti-5553, beta 21s and the like, but the alloys have the problem of lower plasticity when the strength is more than 1250MPa, and the alloys have almost no plasticity when the tensile strength is 1500MPa, taking Ti-5553(Ti-5Al-5Mo-5V-3Cr, U.S. Pat. No.). In addition, the commonly used metastable beta high-strength titanium alloy is added with high-content expensive alloying elements such as V, Nb and Zr, and most of the alloy needs to be processed by thermal deformation plasticity, so the method has the advantages of long flow, large material loss, high production cost and limited large-scale industrial application. Meanwhile, compared with an alpha + beta two-phase titanium alloy, the single-phase metastable beta titanium alloy has the problem of low yield strength and is difficult to adapt to part of industrial application requirements.

Therefore, how to improve the matching of the strength and the plasticity of the titanium alloy and improve the cold deformation processing capability of the titanium alloy is a main problem facing the expansion of the engineering application of the titanium alloy.

Disclosure of Invention

In order to solve the technical problems, the invention provides a high-strength plastic titanium alloy and a preparation method of a forging material and a rolling material thereof; meanwhile, the invention develops the cold deformation processing method and the subsequent heat treatment method of the alloy, after cold rolling deformation and heat treatment, the strength of the alloy is more than 1350MPa, the elongation is more than 10 percent, and the application range of the existing high-strength titanium alloy can be greatly expanded.

The complete technical scheme of the invention comprises the following steps:

a high strength, high plasticity titanium alloy comprising: 3.5 to 4.5 percent of Mo, 2.5 to 3.5 percent of Cr, 0.7 to 1.5 percent of Fe, less than 0.35 percent of O, and the balance of Ti and inevitable impurities, wherein the alloy structure comprises alpha and beta phases, and the content of the alpha phase is more than 5 percent.

A preparation method of a high-strength high-plasticity titanium alloy forging material comprises the following steps:

a1: the raw materials are proportioned according to the mass fraction of 3.5-4.5% of Mo, 2.5-3.5% of Cr, 0.7-1.5% of Fe, less than 0.35% of O and the balance of Ti and inevitable impurities;

a2: smelting the raw materials obtained in the step A1 by using vacuum smelting equipment to obtain alloy ingots with uniform components;

a3: b, cogging and forging the alloy ingot obtained in the step A2, and cooling to room temperature to obtain a forged material;

a4: carrying out solid solution treatment on the finished product obtained in the step A3, and then cooling to room temperature to obtain a titanium alloy;

a5: b, carrying out aging treatment on the titanium alloy obtained in the step A4, and cooling to room temperature to obtain a high-strength high-plasticity titanium alloy;

further, the cogging forging process of the step A3 is that the first fire is subjected to heat preservation at 1050-1150 ℃ and taken out for three-pier three-drawing, and the second fire is subjected to heat preservation at 940-980 ℃ and taken out for three-pier three-drawing;

further, the forging process in the step A3 is changed into five-fire upsetting: the first fire is taken out after heat preservation at 730-770 ℃ for primary pier drawing, the second fire is taken out after heat preservation at 800-830 ℃ for secondary pier drawing, the third fire is taken out after heat preservation at 730-770 ℃ for primary pier drawing, the fourth fire is taken out after heat preservation at 730-770 ℃ for primary pier drawing, the fifth fire is heated at 730-770 ℃ for heat preservation, and the forging stock with the required size is taken out after the piers are drawn;

further, the solution treatment temperature of the step A4 is 730-780 ℃, and the heat preservation time is 0.5-3 h;

further, the aging treatment temperature of the step A5 is 430-530 ℃, and the heat preservation time is 1-8 h;

a preparation method of a high-strength high-plasticity titanium alloy rolled material comprises the following steps:

b1: machining the cogging forging blank obtained in the step A3 to obtain a rolling blank with qualified quality;

b2: heating and insulating the blank obtained in the step B1, and then rolling the blank for multiple times to obtain a rolled alloy;

b3: carrying out solution treatment on the rolled alloy obtained in the step B2, and then cooling to room temperature;

b4: b3, carrying out aging treatment on the solid solution alloy obtained in the step B, and cooling to room temperature to obtain a high-strength high-plasticity titanium alloy;

preferably, the rolling temperature in the step B2 is 730-770 ℃, the reheating and heat preservation time after each pass of rolling is 5-10 min, and the total deformation is more than 85%;

further, the solution treatment temperature in the step B3 is 730-780 ℃, and the heat preservation time is 0.5-3 h;

further, the aging treatment temperature of the step B4 is 430-530 ℃, and the heat preservation time is 1-8 h;

a cold deformation processing and heat treatment method for a high-strength and high-plasticity titanium alloy comprises the following steps:

c1: machining the solid solution alloy obtained in the step A4 or B3 to obtain a qualified blank;

c2: c1, carrying out heat treatment on the blank obtained in the step C, and then carrying out water-cooling quenching to room temperature;

c3: performing cold deformation on the quenched titanium alloy obtained in the step C2 to obtain a cold deformation alloy; the cold deformation processing method can be cold rolling, cold spinning and cold extrusion.

C4: and C3, carrying out heat treatment on the cold deformation alloy obtained in the step C3, and then carrying out air cooling to obtain a finished product.

Further, the heat treatment temperature of the step C2 is 630-700 ℃, and the heating and heat preservation are carried out for 15-60 min;

further, the heat treatment process in the step C4 can be directly preserving the heat at 430-530 ℃ for 30min-5 h;

further, the heat treatment process in the step C4 can also be heat preservation for 0.5-1 h at 730-780 ℃, then air cooling to room temperature, and then heat preservation for 30min-5h at 430-530 ℃.

The prepared high-strength plastic titanium alloy is applied to the manufacturing of parts such as plates, bars, pipes, profiles and the like.

Compared with the prior art, the invention has the advantages that:

1) in order to solve the problem of difficult cold deformation processing of the titanium alloy in the prior art, the titanium alloy only comprises five elements of Ti, Mo, Cr, Fe and O, and does not add alpha stabilizing elements such as Al, Sn and the like, thereby reducing the rheological resistance in the deformation processing, particularly the cold deformation processing process, reducing the cost, improving the plastic processing performance of the alloy and enabling the alloy to have excellent strong plastic matching.

2) Meanwhile, in order to obtain good yield strength and avoid the alloy structure from becoming single-phase metastable beta alloy, under the condition of not adding alpha stabilizing elements such as Al, Sn and the like, the invention obtains the alpha + beta two-phase titanium alloy with isometric alpha phase volume fraction more than 10% by adopting specific cogging forging and re-forging processes and combining with the heat treatment to regulate and control the content of the alpha phase in the structure and the distribution of alloying elements in the alpha phase and the beta phase, simultaneously has excellent cold deformability, has the deformation amount reaching over 75%, and overcomes the defect that the traditional two-phase titanium alloy is difficult to realize large-deformation cold processing.

3) The titanium alloy can be applied to producing bars, plates and pipes and further cold-processing the bars, the plates and the pipes into parts and the like, and has wide application value in the fields of aviation, aerospace, petrochemical industry, weaponry and the like.

Drawings

FIG. 1 is an optical structure of a solid solution titanium alloy after forging in example 1 of the present invention.

FIG. 2 is a graph showing the tensile properties of the titanium alloy in a heat-treated state after forging in example 1 of the present invention.

FIG. 3 is a scanning electron micrograph of the alloy in a solid solution aged state after rolling in example 2 of the present invention.

FIG. 4 is a graph showing the tensile properties of the titanium alloy in the cold rolled heat treated state in example 3 of the present invention.

FIG. 5 is a comparison graph of the appearance and the appearance of the cold rolling in example 3 of the present invention.

Detailed Description

The following description of the embodiments of the present invention, with reference to the accompanying drawings, will be made to the embodiments of the present invention, such as the designed mutual positions and connection relationships of the various parts, the functions and working principles of the various parts, the manufacturing process and the operation and use method, etc., for further detailed description, so as to help those skilled in the art to more completely, accurately and deeply understand the inventive concept and technical scheme of the present invention.

Example 1

The high-strength high-plasticity titanium alloy comprises the following components in percentage by weight: 4.23% of Mo, 2.90% of Cr, 0.80% of Fe0, less than 0.18% of O, and the balance of Ti and inevitable impurities. In the embodiment, through reasonable component design, only five elements of Ti, Mo, Cr, Fe and O are included, the addition of alpha stable elements such as Al, Sn and the like is avoided, meanwhile, the content of an alpha phase in a structure and the distribution of alloying elements in the alpha phase and the beta phase are regulated and controlled through specific cogging forging and reforming forging processes in combination with heat treatment, so that the alpha + beta two-phase titanium alloy is obtained, the cost is reduced, the plastic processing performance of the alloy is improved, and the alloy has excellent strong plastic matching.

The preparation method of the high-strength and high-plasticity titanium alloy in the embodiment comprises the following steps:

s1 prefabricated electrode: 1.32kg of Ti-32Mo intermediate alloy, 0.3kg of chromium sheet and 0.09kg of iron particles are uniformly mixed, and the mixed material is placed in the middle of 8.29kg of sponge titanium and is pressed and molded to obtain a blocky prefabricated electrode; the mass purities of the chromium sheets and the iron particles are both 99.9%, wherein the maximum diameter of the iron particles is more than 3 mm.

S2 ingot casting: and (4) connecting the prefabricated electrodes obtained in the step (S1) into an electrode, and carrying out three times of smelting in a vacuum consumable arc furnace to obtain an ingot.

S3 cogging forging: sequentially removing surface floating skins and cutting off risers from the cast ingot obtained in the step S2 to obtain 150kg of blank with the diameter of 215mm and the length of 440mm, putting the blank into a resistance furnace at 1150 ℃ for heat preservation for 4h, then performing first hot cogging forging of three piers and three pulls on a 20MN fast forging machine, wherein the steps comprise firstly upsetting to the height of 300mm, then pulling a hexagonal rolling circle to the diameter of 200mm, then repeating the upsetting for 2 times, and performing air cooling after forging; then, after the temperature is kept at 950 ℃ for 4 hours, carrying out second hot cogging forging of three piers and three pulls, wherein the procedure is to firstly pier the titanium alloy to a height of 300mm, then pull the hexagonal round to a diameter of 200mm, repeat the pier pulling for 2 times, and finally obtain a titanium alloy forging stock; the total deformation of the cogging forging was 150%.

S4 forging: and (3) carrying out five-fire re-forging on the titanium alloy forging stock obtained in the step S3: a first fire: putting the mixture into a resistance furnace, heating and preserving heat for 3 hours at 760 ℃, taking out the mixture, and forging the mixture by one pier and one pull: firstly, upsetting a blank to 410mm, then turning over for 180 degrees, upsetting to 300mm, axially drawing a hexagon, rounding to the diameter of 200mm, and then air cooling; and (3) second fire: heating and preserving heat for 3h at 820 ℃, taking out and forging by two piers and two drawing: firstly, upsetting a blank to 410mm, then turning over for 180 degrees, upsetting to 300mm, axially drawing a hexagon, rounding to a diameter of 200mm, repeating upsetting for 1 time, and then air-cooling; and (3) third fire: heating and insulating for 3h at 760 ℃, taking out and forging by one pier and one drawing: firstly, upsetting a blank to 410mm, then turning over for 180 degrees, upsetting to 300mm, axially drawing a hexagon, and then returning to the furnace; and (4) fourth fire: keeping the temperature at 760 ℃ for 1h, taking out and forging the blank by one pier and one drawing: firstly, upsetting a blank to 410mm, then turning over for 180 degrees, upsetting to 300mm, axially drawing a hexagon, and then returning to the furnace; and (5) fifth fire: keeping the temperature at 760 ℃ for 1h, taking out and drawing out: the blank was axially hexagonal and rounded to a diameter of 160 mm.

S5 solution treatment: and (3) carrying out solution treatment on the forged blank obtained in the step S4 at 750 ℃/1h and cooling the forged blank to room temperature by water to obtain a solid solution alloy.

S6 aging heat treatment: artificially aging the solid solution alloy obtained in the S5 for 6h at 470 ℃ to obtain an aged alloy.

The structure was observed by an optical microscope, and it was shown that the solid solution alloy contained an equiaxed alpha phase with a volume fraction of about 12%, as shown in fig. 1. Uniaxial tensile testing was performed using a universal testing machine model INSTRON 8801 and a typical tensile curve is shown in figure 2. It can be seen that both the solid solution and aged alloys have good strength and plasticity matches. Wherein the tensile strength of the solid solution alloy is 1031MPa, and the elongation is 34.0%; the tensile strength of the alloy in the solid solution state was 1141MPa, and the elongation thereof was 11.1%.

Example 2

Cogging and forging the cast ingot obtained in the step S2 in the embodiment 1 into a square billet, then placing the square billet into a resistance furnace, heating the square billet to 740 ℃, preserving heat for 1 hour, carrying out multi-pass rolling, removing a surface oxide layer and cleaning to obtain a titanium alloy rolled plate; in the multi-pass rolling process, after each pass of rolling, the titanium alloy forging stock is placed in a resistance furnace to be heated to 740 ℃ and kept warm for 10 min; the total deformation of the multi-pass rolling is 80%.

The alloy in a rolling state is subjected to solution treatment at 750 ℃/30min and then is cooled to room temperature by water, and the obtained solid solution structure contains equiaxial alpha phase with volume fraction of about 10%, and has the tensile strength of 1168MPa and the elongation of 36.2%.

The solid solution alloy was artificially aged at 480 ℃ for 4 hours to obtain an aged microstructure as a two-phase microstructure, as shown in fig. 3, containing about 15% by volume of primary equiaxed alpha phase and a large amount of ultra-fine alpha phase in the remaining beta phase region. The tensile test result shows that the tensile strength of the alloy in an aged state is 1326MPa, and the elongation is 16%.

Example 3

The embodiment is a preparation method of a cold-rolled sheet, which comprises the following specific steps:

s1: the solid-solution forged blank obtained in step S4 of example 1 was machined into a slab.

S2: the plate blank of the step S1 is kept at 650 ℃ for 30min, the content and element distribution of alpha and beta phases in the tissue are regulated and controlled, and then water-cooling quenching is carried out to room temperature; the rolling is directly heat treated by 650 degrees in a forging state.

S3: removing oxide skin of the plate blank obtained in the step S2, cleaning, and performing multi-pass cold rolling deformation at room temperature, wherein the total deformation is more than 85%, so as to obtain a plate with the thickness of 1.5 mm; FIG. 5a shows the appearance of the cold rolled sheet, and it can be seen that the surface quality is good.

S4: aging the S3 cold-rolled sheet at 460 ℃ for 1h, wherein the tensile strength is 1460MPa, and the elongation is 8.3%.

S5: the S3 cold-rolled sheet is subjected to solution treatment at 750 ℃/30min, the obtained structure type is that a beta matrix contains an equiaxed alpha phase with the volume fraction of about 12%, and the tensile strength and the elongation of the alloy are 1169MPa and 36.0% respectively.

S5: the solid solution alloy obtained from S5 is aged for 6h at 450 ℃, which is different from the solid solution structure, a large amount of fine equiaxed alpha phase is precipitated in the structure, the tensile curve is shown in figure 4, and the tensile strength and the elongation of the alloy are 1407MPa and 14.0 percent respectively.

In order to comparatively illustrate the beneficial effects of the step S2, the 730-780 ℃ solid solution state plate is directly subjected to cold rolling, and the alloy is found to have poor cold rolling deformability and easy rolling cracking, as shown in FIG. 5 b.

Example 4

The high-strength plastic titanium alloy comprises the following components in percentage by weight: 3.8% of Mo, 3.30% of Cr, 1.22% of Fe, 0.27% of O, and the balance of Ti and inevitable impurities. The specific preparation steps of the forged blank are the same as those in example 1, and are not described herein again.

The forging stock of the embodiment 4 is subjected to solution treatment for 2h at 780 ℃, and is cooled to room temperature by water, so that the solid solution alloy containing 10% of equiaxial alpha phase by volume fraction is obtained, the tensile strength of the alloy is 1108MPa, and the elongation of the alloy is 36%; the solid solution alloy is aged for 6h at 500 ℃, and the tensile strength and the elongation are 1285MPa and 18 percent respectively.

Example 5

In this embodiment, the forged blank of example 4 is subjected to multi-pass hot rolling after being heated and heat-preserved at 750 ℃, and the specific steps are the same as those of example 2, and are not described herein again. Carrying out solution treatment on the hot rolled plate at 770 ℃ for 2h, and cooling the hot rolled plate to room temperature by water, wherein the tensile strength of the hot rolled plate is 1132MPa, and the elongation of the hot rolled plate is 34%; aging the rolled alloy in a solid solution state at 470 ℃ for 5h, wherein the tensile strength and the elongation are 1387MPa and 13 percent respectively.

Example 6

In this embodiment, the hot rolled plate of example 5 is subjected to solution treatment at 770 ℃ for 2h, then is subjected to heat preservation at 680 ℃ for 30min, is water-cooled and quenched to room temperature, and is then subjected to cold rolling deformation, and specific steps are the same as those of example 3, and are not repeated herein. Carrying out solution treatment on the cold-rolled and deformed plate at 760 ℃ for 2h, wherein the tensile strength and the elongation are 1145MPa and 34 percent respectively; the cold rolled solid solution alloy was aged at 460 ℃ for 4h with tensile strength and elongation of 1415MPa and 12%, respectively.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a high-strength plastic titanium alloy suitable for cold deformation processing is characterized in that the alloy comprises the following components: according to mass fraction Mo 3.5-4.5%, Cr 2.5-3.5%, Fe 0.7-1.5%, O < 0.35%, and the balance Ti and unavoidable impurities;

the preparation process comprises the following steps:

s1: the raw materials are proportioned according to the mass fraction of 3.5-4.5% of Mo, 2.5-3.5% of Cr, 0.7-1.5% of Fe, less than 0.35% of O and the balance of Ti and inevitable impurities;

s2: smelting the raw material obtained in the step S1 to obtain an ingot;

s3: preserving the heat of the titanium alloy ingot obtained in the step S2 at 1050-1150 ℃, and taking out the titanium alloy ingot to perform first-time cogging forging of three piers and three pulls; then preserving heat at 940-980 ℃, and taking out to perform secondary hot cogging forging of three piers and three pulls; the total deformation amount of the cogging forging is not less than 150%;

s4: performing 5-time upsetting on the titanium alloy forging stock obtained in the step S3, wherein the 1 st heating: heating and preserving heat at 730-770 ℃, taking out, and forging by one pier and one pull; fire 2: heating and preserving heat at 800-830 ℃, taking out and forging two piers and two pulls; fire 3: heating and preserving heat at 730-770 ℃, taking out, and forging by one pier and one pull; fire 4: heating and preserving heat at 730-770 ℃, taking out and forging by one pier and one pull; fire 5: heating and preserving heat at 730-770 ℃, taking out a forged blank forged to a required size, and then air-cooling.

2. The method for preparing a high-strength plastic titanium alloy suitable for cold deformation processing according to claim 1,

further comprising S5: carrying out solution treatment on the forging stock obtained in the step S4 at 730-790 ℃, and then air-cooling or water-cooling to room temperature; the volume fraction of alpha phase in the obtained solid solution alloy structure is more than 5 percent, the tensile strength is more than 1000MPa, and the elongation is more than 30 percent.

3. The method for preparing a high-strength plastic titanium alloy suitable for cold deformation processing according to claim 2,

further comprising S6: carrying out artificial aging on the solid solution alloy obtained in the step S5 for 1-8 h at the temperature of 430-530 ℃; the obtained alloy in an aging state has the tensile strength of more than 1250MPa and the elongation of more than 10 percent.

4. The method for preparing a high-strength plastic titanium alloy suitable for cold deformation processing according to claim 1,

further comprising S5: performing multi-pass rolling on the forged blank obtained in the step S4 after heat preservation at 710-780 ℃; in the multi-pass rolling process, after each pass of rolling, putting the rolled steel sheet into a resistance furnace again to be heated to the rolling temperature and preserving the heat for 5-10 min; the total deformation of the multi-pass rolling is more than 85%.

5. The method for preparing the high-strength plastic titanium alloy suitable for cold deformation processing as claimed in claim 4, further comprising S6: carrying out solution treatment on the rolled alloy obtained in the step S5 at 730-780 ℃, and then carrying out water cooling to room temperature; the volume fraction of alpha phase in the obtained solid solution alloy structure is more than 10%, the tensile strength is more than 1050MPa, and the elongation is more than 35%.

6. The method for preparing a high-strength plastic titanium alloy suitable for cold-deformation processing as claimed in claim 5, further comprising S7: carrying out artificial aging on the solid solution alloy obtained in the step S6 for 1-8 h at the temperature of 430-530 ℃; the obtained alloy in an aging state has the tensile strength of more than 1350MPa and the elongation of more than 12 percent.

7. The method for preparing a high strength plastic titanium alloy suitable for cold deformation processing according to claim 1, 2 or 5, further comprising the steps of:

1) heating and insulating the alloy at 630-700 ℃ for 30min-5h, and quenching to room temperature, wherein the volume fraction of an alpha phase in the structure is more than 15%;

2) machining the heat-treated alloy obtained in the step 1) into a plate blank, and performing multi-pass cold deformation at room temperature, wherein the total deformation of the multi-pass cold deformation is more than 85%;

3) directly carrying out artificial aging on the alloy subjected to cold deformation in the step 2) at 430-530 ℃ for 30min-5h, wherein the tensile strength of the obtained aged alloy is greater than 1450MPa, and the elongation is greater than 10%;

wherein, the step 3) may also be: preserving the heat of the alloy subjected to cold deformation in the step 2) at 730-780 ℃ for 0.5-1 h, then air-cooling to room temperature, and then carrying out aging treatment at 430-530 ℃ for 30min-5h, wherein the tensile strength of the obtained aged alloy is more than 1350MPa, and the elongation is more than 15%.

8. The method of producing a high strength plastic titanium alloy suitable for cold deformation processing as claimed in claim 1, 2 or 5, further comprising:

1) heating the alloy at 790-820 ℃ for 30min-2h, cooling the alloy in a furnace to 620-670 ℃, preserving the heat for 30min-5h, and then performing air cooling, wherein the volume fraction of an alpha phase in the structure is more than 15%;

3) directly carrying out artificial aging on the alloy subjected to cold deformation in the step 2) at 430-530 ℃ for 30min-5h, wherein the tensile strength of the obtained aged alloy is greater than 1300MPa, and the elongation is greater than 8%;

wherein, the step 3) may also be: preserving the heat of the alloy subjected to cold deformation in the step 2) at 730-780 ℃ for 0.5-1 h, then air-cooling to room temperature, and then carrying out aging treatment at 430-530 ℃ for 30min-5h, wherein the tensile strength of the obtained aged alloy is larger than 1250MPa, and the elongation is larger than 12%.

9. A high strength plastic titanium alloy suitable for cold deformation processing according to any one of claims 1 to 8.

10. Use of the high strength plastic titanium alloy of claim 9 in the manufacture of plates, rods, tubes and profiles.