A high-performance titanium alloy with strong uniform deformation ability and its preparation method

Abstract

The present invention provides a high-performance titanium alloy with strong uniform deformation ability and a preparation method thereof. The titanium alloy is composed of the following elements in mass percentages: Cr is 4.8-5.8%, Mo is 1.2-2.2%, Sn is 1.5-2.5%, Zr is 0.6-1.2%, and the balance is Ti and inevitable impurity elements. The preparation method includes: melting and casting ingots, deformation processing, and annealing treatment. The concept of the present invention is reasonable. Based on the stress-induced response toughening mechanism of the metastable β phase of titanium alloy, a high-performance titanium alloy with strong uniform deformation ability and a preparation method thereof are developed, solving the key technical problems of low uniform elongation rate of traditional titanium alloys and being unsuitable for room-temperature stamping forming, and having production promotion and potential application prospects in the room-temperature processing of complex components such as aviation, aerospace, and ships.

Description

Technical Field

[0001] The present invention belongs to the technical field of advanced metal materials, and particularly relates to a high-performance titanium alloy with strong uniform deformation ability and a preparation method thereof. Background Art

[0002] The key performance index for metal materials suitable for deep drawing / stretching room-temperature processing and forming is to have excellent uniform elongation, that is, the ability to plastically deform uniformly during the stretching process, which is directly related to the strain hardening ability of the material. High uniform elongation usually means that the material can continuously absorb energy during the plastic deformation process. The stronger the plastic deformation ability in the uniform deformation stage, the stronger its ability to resist local concentrated deformation (such as defects, necking, fracture). It is the core index for material design, engineering material selection, and performance optimization.

[0003] Titanium alloys have excellent comprehensive properties such as low density, high strength, and corrosion resistance, and have a wide range of key applications in the fields of aviation, aerospace, ships, etc. However, the room-temperature uniform deformation ability of traditional medium / high-strength titanium alloys is poor. For example, the uniform elongation of the commonly used TC4 titanium alloy is 8-12%, and the uniform elongation of most high-strength titanium alloys is less than 8%. To address the technical problem of poor uniform deformation ability of titanium alloys, there are currently two commonly used solutions in engineering practice: one is to complete the processing and preparation of complex parts of traditional titanium alloys under high-temperature conditions, but high-temperature processing will cause new problems such as uneven internal stress distribution and surface oxidation in titanium alloy workpieces; the other idea is to perform multi-pass small-deformation processing at room temperature and then combine it with a stress-relieving annealing process to prepare complex titanium alloy parts, but this method causes technical problems such as long preparation processes, high processing costs, and low efficiency for traditional titanium alloys. Thus, it can be seen that neither of these two current process technologies has solved the technical problems of the complex room-temperature forming and processing technology of traditional titanium alloys.

[0004] To overcome the above problems, developing a high-performance titanium alloy with strong uniform deformation ability and its preparation method can effectively solve the problems of poor uniform deformation ability of traditional titanium alloys and their inapplicability to complex room-temperature forming and processing technologies, significantly improve the processing efficiency of titanium alloys, and reduce their processing and preparation costs. It has production promotion and potential application prospects in the room-temperature processing of complex parts such as aviation, aerospace, and ships. Summary of the Invention

[0005] In view of the technical problems existing in the above-mentioned background art, the present invention provides a high-performance titanium alloy with strong uniform deformation ability and a preparation method thereof. The concept is reasonable. According to the design principle of titanium alloy composition and based on the stress-induced response toughening mechanism of alloy metastable β phase, a high-performance titanium alloy with strong uniform deformation ability and a preparation method thereof are developed, effectively solving the key technical problems of low uniform elongation rate of traditional titanium alloys and unsuitability for room-temperature stamping forming, and having production promotion and potential application prospects in the room-temperature processing of complex components such as aviation, aerospace, and ships.

[0006] To solve the above technical problems, a high-performance titanium alloy with strong uniform deformation ability provided by the present invention is composed of the following elements in mass percentages: Cr is 4.8 - 5.8%, Mo is 1.2 - 2.2%, Sn is 1.5 - 2.5%, Zr is 0.6 - 1.2%, and the balance is Ti and inevitable impurity elements.

[0007] The high-performance titanium alloy with strong uniform deformation ability, wherein: the alloy is within the d parameter range in the electronic titanium alloy design theory of 2.391 ≤ ≤ 2.418, parameter range of 2.782 ≤ ≤ 2.798.

[0008] The high-performance titanium alloy with strong uniform deformation ability, wherein: the uniform elongation ε uni ≥ 30% of the alloy, the fracture elongation 40% ≤ ε f ≤ 55%, the yield strength , the tensile strength , and the characteristic peak value of the work hardening rate is greater than 1 GPa.

[0009] A preparation method of a high-performance titanium alloy with strong uniform deformation ability mainly includes the following steps:

[0010] (1) Melting and casting ingots

[0011] Using titanium sponge, pure chromium flakes, pure molybdenum particles, sponge zirconium, and titanium-tin master alloy as raw materials and proportioning according to the set alloy mass percentages, and then placing the proportioned raw materials in the cold crucible of a vacuum induction levitation melting furnace, and using the vacuum induction levitation melting furnace to melt repeatedly to pour and obtain alloy ingots;

[0012] (2) Deformation processing

[0013] Put the alloy ingot in step (1) into a vacuum heat treatment furnace. Heat it in the vacuum heat treatment furnace to temperature T1 and hold for time t1, then air cool to room temperature. Subsequently, put the alloy ingot into a general heat treatment furnace at temperature T2 and hold for time t2. Take it out and perform multi-pass rolling deformation processing to obtain the primary alloy sheet;

[0014] (3) Annealing treatment

[0015] Put the primary alloy sheet obtained in step (2) into a general heat treatment furnace at temperature T3 and hold for time t3. Take it out and put it into a saline solution at room temperature for rapid cooling. Subsequently, polish its surface to obtain a high-performance titanium alloy material.

[0016] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: when the raw materials in step (1) are first melted in a vacuum induction levitation melting furnace, put the sponge titanium at the upper and lower parts of the cold crucible, mix the pure chromium flakes, pure molybdenum particles and sponge zircon and put them at the edge of the middle part of the crucible, and put the titanium-tin intermediate alloy at the center of the middle part of the crucible.

[0017] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: in step (1), the raw materials placed in the cold crucible are repeatedly melted 2-3 times by using a vacuum induction levitation melting furnace.

[0018] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: in step (2), the temperature T1 is 1050 °C to 1200 °C, and the time t1 is 2 h to 4 h; the temperature T2 is 600 °C to 760 °C, and the time t2 is 5 min to 60 min.

[0019] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: in step (2), the heating rate of the vacuum heat treatment furnace is 5 °C / min - 10 °C / min, and the vacuum degree is 1.0x10 -3 Pa to 3.5x10 -3 Pa.

[0020] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: in step (2), the deformation amount of each pass of rolling deformation is 2% - 10%, and the cumulative deformation amount ≥ 80%.

[0021] The preparation method of the high-performance titanium alloy with strong uniform deformation ability, wherein: in step (3), the temperature T3 is 650 °C to 860 °C, and the time t3 is 5 min to 120 min.

[0022] The method for preparing a high-performance titanium alloy with strong uniform deformation ability, wherein: the ratio of the saline solution in step (3) is NaCl: 8-12wt.%, and the balance is water.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] In the research and development of high-performance titanium alloy with strong uniform deformation ability, in order to obtain excellent uniform elongation, the present invention focuses on combining the low alloying principle of titanium alloy and d Based on the theory of electronic alloy design, alloy composition design is explored. First of all, in order to obtain the room temperature metastable β phase structure, the traditional metastable β titanium alloy has the phenomenon of excessive total alloying addition (η≥20wt.%, such as β-C: Ti-8V-6Cr-4Mo-4Zr-3Al) or excessive single alloying (η≥15wt.%, such as Ti-15-3: Ti-15V-3Cr-3Sn-3Al) during alloying design. Excessive alloying addition is an important reason for the poor homogenization elongation of titanium alloys. On the other hand, the strain induced plasticity / twin induced plasticity (TRIP / TWIP) effect can significantly improve the plastic deformation ability of titanium alloys, and titanium alloys d Electronic design theory can achieve TRIP / TWIP effect through different alloying additions from the perspective of alloy stability regulation. Based on this, in the design of alloy composition, the addition amount of a single main alloying element is controlled to η≤6%, and the total alloying element addition amount is controlled to η≤12% to reduce alloying addition; in addition, the strong β-stabilizing element Cr is selected as the main alloying element, and a small amount of Mo, Sn, and Zr elements are used to combine with titanium alloy. d The electronic design theory was used to regulate the alloy stability to obtain the TRIP / TWIP toughening mechanism, and finally the Ti-Cr-Mo-Sn-Zr high-performance titanium alloy with strong uniform deformation ability was successfully developed.

[0025] When developing a high-performance titanium alloy with strong uniform deformation ability, the present invention selected the Cr element with the second strongest β-phase stability instead of the strongest Fe element according to the Mo equivalent empirical formula. The reason is that as eutectoid β-stabilizing elements, Cr and Fe elements both have strong β-phase stabilizing ability, but Fe element has poor thermal stability. When the addition amount exceeds 2% during smelting, it is easy to segregate and form "β spots", which increases the difficulty of alloy processing and preparation, and is not conducive to room temperature processing of the alloy.

[0026] The present invention is to develop a high-performance titanium alloy with strong uniform deformation ability according to the titanium alloy d Electronic Design Theory and The alloy stability is adjusted by adjusting the parameters, and the alloy stability is positioned at the junction of TRIP and TWIP, which is slightly biased towards TRIP, that is, 2.391≤ ≤2.418, 2.782≤ ≤2.798. The main reason is that strain-induced phase transformation usually has a lower yield strength, a faster dynamic strengthening and toughening ability, and a stronger work hardening ability, etc., which can endow the alloy with a stronger uniform deformation ability.

[0027] When developing a preparation method for a high-performance titanium alloy with a strong uniform deformation ability, in order to reduce the loss of raw materials and obtain an ingot with uniform composition, during the first ingot melting using a cold crucible vacuum induction levitation melting furnace, the raw materials are placed in the cold crucible in an orderly manner, that is, titanium sponge is placed at the upper and lower parts of the cold crucible, pure chromium sheets, pure molybdenum particles and titanium sponge are mixed and placed at the edge of the middle part of the crucible, and titanium-tin master alloy is placed at the center of the middle part of the crucible, laying a foundation for obtaining high-quality ingots.

[0028] When developing a preparation method for a high-performance titanium alloy with a strong uniform deformation ability, a high-temperature homogenization treatment is carried out before deformation processing. On the one hand, it reduces the elemental interdendritic segregation formed during the solidification of the alloy ingot, and on the other hand, it obtains coarse β grains with uniform sizes on the surface layer and the core of the ingot, laying a foundation for the uniform deformation of the surface layer and the core of the alloy. In the processing deformation stage, combined with the dynamic strengthening and toughening effects of TRIP / TWIP, the deformation amount per pass can be increased, thereby reducing the number of rolling passes and shortening the processing and preparation process.

[0029] Using the preparation method of the present invention, not only a high-performance titanium alloy material with a high uniform elongation rate (ε uni ≥30%) is obtained, but also this alloy has both a high fracture elongation rate (40%≤ε f ≤55%), a relatively high yield strength and tensile strength , as well as excellent work hardening performance. Thus, it can be seen that the preparation method of the present invention solves the key technical problems of low uniform elongation rate of traditional titanium alloys and being unsuitable for room-temperature stamping forming, and has a production promotion and potential application prospect in the room-temperature processing of complex components such as aviation, aerospace, and ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 It is a flow schematic diagram of the preparation method for a high-performance titanium alloy with a strong uniform deformation ability of the present invention;

[0032] Figure 2 Tensile property curve of the high-performance titanium alloy with strong uniform deformation ability of the present invention;

[0033] Figure 3 Work hardening curve of the high-performance titanium alloy with strong uniform deformation ability of the present invention;

[0034] Figure 4 Macrograph of the fracture surface of the high-performance titanium alloy with strong uniform deformation ability in Example 3 of the present invention;

[0035] Figure 5 Micrograph of the fracture surface of the high-performance titanium alloy with strong uniform deformation ability in Example 3 of the present invention. Detailed implementation manners

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] The present invention will be further explained and described below in conjunction with specific implementation manners.

[0038] As Figure 1 shown, a high-performance titanium alloy with strong uniform deformation ability provided in this embodiment is composed of the following elements in mass percentages: Cr is 4.8 - 5.8%, Mo is 1.2 - 2.2%, Sn is 1.5 - 2.5%, Zr is 0.6 - 1.2%, and the balance is Ti and inevitable impurity elements.

[0039] A high-performance titanium alloy with strong uniform deformation ability provided by the present invention in d the electronic titanium alloy design theory and the parameter range is 2.391 ≤ ≤ 2.418, 2.782 ≤ ≤ 2.798.

[0040] As Figure 1 shown, the preparation method of the high-performance titanium alloy with strong uniform deformation ability provided by the present invention mainly includes the following steps:

[0041] S010. Melting and ingot casting

[0042] Using titanium sponge, pure chromium flakes, pure molybdenum particles, zirconium sponge and titanium-tin master alloy as raw materials, the composition ratio is carried out according to the designed alloy mass percentage. When melting for the first time, the titanium sponge is placed at the upper and lower parts of the cold crucible, the pure chromium flakes, pure molybdenum particles and zirconium sponge are mixed and placed at the edge of the middle part of the crucible, and the titanium-tin master alloy is placed at the center of the middle part of the crucible. The vacuum induction levitation melting furnace is used to repeat melting 2-3 times, and finally an alloy ingot is obtained by casting;

[0043] S020, deformation processing

[0044] Put the alloy ingot obtained in step S010 into a vacuum heat treatment furnace, evacuate to a vacuum degree of 1.0x10 -3 ~3.5x10 - 3 Pa, then heat it in the furnace at a heating rate of 5-10 °C / min to a temperature T1 of 1050 °C - 1200 °C, keep it warm for a time t1 of 2h - 4h, and then air-cool it to room temperature. Subsequently, put the alloy ingot into a general heat treatment furnace at a temperature T2 of 600 °C - 760 °C and keep it warm for a time t2 of 5 - 60 min. After taking it out and performing multi-pass rolling deformation processing, the deformation amount of each pass is 5 - 15%, and the cumulative deformation amount is greater than or equal to 80%. Finally, an alloy primary sheet is obtained;

[0045] S030, annealing treatment

[0046] Put the alloy primary sheet obtained in step S020 into a heat treatment furnace at a temperature T3 of 650 °C - 860 °C and keep it warm for a time t3 of 5 min - 120 min. Take it out and quickly cool it in water. Subsequently, polish its surface to obtain a high-performance titanium alloy material;

[0047] A high-performance titanium alloy provided by the present invention has a strong uniform deformation ability, and its mechanical property indexes are uniform elongation ε uni ≥30%, fracture elongation 40% ≤ ε f ≤55%, yield strength tensile strength , and the characteristic peak value of the work hardening rate is greater than 1 GPa. It can be seen that the high-performance titanium alloy provided by the present invention has excellent comprehensive mechanical properties such as strong uniform deformation ability, ultra-high plasticity and good work hardening ability, and has production promotion and potential application prospects in the room temperature processing of complex components such as aviation, aerospace and ships.

[0048] Example 1:

[0049] In Example 1 of the present invention, a high-performance titanium alloy with strong uniform deformation ability is composed of the following elements in mass percentages: Cr is 5.5%, Mo is 1.8%, Sn is 1.8%, Zr is 0.8%, and the balance is Ti and inevitable impurity elements.

[0050] The high-performance titanium alloy with strong uniform deformation ability provided in Example 1 of the present invention d in the electronic titanium alloy design theory and the parameters are 2.392 and 2.789 respectively.

[0051] Combined with Figure 1 as shown, a preparation method of a high-performance titanium alloy with strong uniform deformation ability provided by the present invention, with a predetermined melting ingot mass of 2 kg, may specifically include the following steps:

[0052] S110. Melting the ingot

[0053] Using titanium sponge, pure chromium flakes, pure molybdenum particles, sponge zirconium and titanium-tin master alloy as raw materials, proportioning according to the designed alloy mass percentages. When melting for the first time, place the titanium sponge at the upper and lower parts of the cold crucible, place the mixture of pure chromium flakes, pure molybdenum particles and sponge zirconium at the edge of the middle part of the crucible, and place the titanium-tin master alloy at the center of the middle part of the crucible. Use a vacuum induction levitation melting furnace to melt repeatedly for 3 times, and finally pour to obtain an alloy ingot;

[0054] S120. Deformation processing

[0055] Put the alloy ingot obtained in step S110 into a vacuum heat treatment furnace, evacuate to a vacuum degree of 3.0x10 -3 Pa, then heat it in the furnace at a heating rate of 8 °C / min to a temperature T1 of 1080 °C, keep it warm for a time t1 of 3 h, and then air-cool to room temperature. Subsequently, put the alloy ingot into a general heat treatment furnace at a temperature T2 of 700 °C and keep it warm for a time t2 of 10 min. Take it out and perform multi-pass rolling deformation processing. The deformation amount per pass is 6%, and the cumulative deformation amount is about 84%. Finally, obtain an alloy primary sheet;

[0056] S130. Annealing treatment

[0057] Put the alloy primary sheet obtained in step S120 into a heat treatment furnace at a temperature T3 of 810 °C and keep it warm for a time t3 of 20 min. Take it out and put it into water for rapid cooling. Subsequently, polish its surface to obtain a high-performance titanium alloy material;

[0058] As Figure 2 shown by curve 1, for the high-performance titanium alloy with strong uniform deformation ability provided in this Example 1, its mechanical property index is the uniform elongation εuni is about 32%, the elongation at break is about 45%, the yield strength is about 670 MPa, the tensile strength is about 823 MPa, and the peak value of the work hardening rate is about 2.0 GPa (as shown by curve 1 in Figure 3 ). It can be seen that the high-performance titanium alloy provided by the present invention has excellent comprehensive mechanical properties such as strong uniform deformation ability, ultra-high plasticity and good work hardening ability, and has production promotion and potential application prospects in the room temperature processing of complex components such as aviation, aerospace and ships.

[0059] Example 2:

[0060] The high-performance titanium alloy with strong uniform deformation ability in Example 2 of the present invention is composed of the following elements by mass percentage: Cr is 5.2%, Mo is 2.1%, Sn is 2.0%, Zr is 0.8%, and the balance is Ti and inevitable impurity elements.

[0061] The high-performance titanium alloy with strong uniform deformation ability provided in Example 2 of the present invention, in d the electronic titanium alloy design theory, its and parameters are 2.394 and 2.789 respectively.

[0062] Combined with Figure 1 shown, a preparation method of a high-performance titanium alloy with strong uniform deformation ability provided by the present invention, the predetermined mass of the melting ingot is 2 kg, and the specific steps may include the following:

[0063] S210. Melting the ingot:

[0064] Using titanium sponge, pure chromium flakes, pure molybdenum particles, sponge zirconium and titanium-tin master alloy as raw materials, and performing ingredient ratio according to the designed alloy mass percentage. When melting for the first time, place the titanium sponge at the upper and lower parts of the cold crucible, place the mixture of pure chromium flakes, pure molybdenum particles and sponge zirconium at the edge of the middle part of the crucible, and place the titanium-tin master alloy at the center of the middle part of the crucible. Use a vacuum induction levitation melting furnace to melt repeatedly for 3 times, and finally pour to obtain an alloy ingot;

[0065] S220. Deformation processing

[0066] Put the alloy ingot obtained in step S210 into a vacuum heat treatment furnace, and evacuate to 2.7x10 -3Pa, and then heated in the furnace at a heating rate of 10 °C / min to a temperature T1 of 1100 °C, held for a holding time t1 of 2.5 h, and then air-cooled to room temperature. Subsequently, the alloy ingot was placed in a conventional heat treatment furnace at a temperature T2 of 720 °C and held for a holding time t2 of 10 min. After being taken out and subjected to multi-pass rolling deformation processing, the deformation amount per pass was 10%, and the cumulative deformation amount was approximately 90%. Finally, the alloy primary sheet was obtained;

[0067] S230, annealing treatment

[0068] The alloy primary sheet obtained in step S220 was placed in a heat treatment furnace at a temperature T3 of 820 °C and held for a holding time t3 of 8 min, taken out and quickly cooled in water, and then its surface was polished to obtain a high-performance titanium alloy material;

[0069] As Figure 2 shown by curve 2 in uni , a high-performance titanium alloy with strong uniform deformation ability provided in Example 1 of the present invention has mechanical property indexes of uniform elongation ε Figure 3 of approximately 33%, fracture elongation of approximately 48%, yield strength of approximately 748 MPa, tensile strength of approximately 896 MPa, and a characteristic peak value of work hardening rate of approximately 2.0 GPa (as

[0070] shown by curve 2 in

[0071] ). Thus, it can be seen that the high-performance titanium alloy provided by the present invention has excellent comprehensive mechanical properties such as strong uniform deformation ability, ultra-high plasticity, and good work hardening ability, and has production promotion and potential application prospects in the room-temperature processing of complex components such as aviation, aerospace, and ships.

[0072] The high-performance titanium alloy with strong uniform deformation ability provided in Example 2 of the present invention has d parameters of 2.396 and 2.789 respectively in the electronic titanium alloy design theory and .

[0073] Combined with Figure 1 shown, a preparation method of a high-performance titanium alloy with strong uniform deformation ability provided by the present invention has a predetermined melting ingot mass of 2 kg, and specifically may include the following steps:

[0074] S310, melting ingot

[0075] Using titanium sponge, pure chromium flakes, pure molybdenum particles, zirconium sponge and titanium-tin master alloy as raw materials, the component ratio is carried out according to the designed alloy mass percentage. When melting for the first time, the titanium sponge is placed in the upper and lower parts of the cold crucible, the pure chromium flakes, pure molybdenum particles and zirconium sponge are mixed and placed at the edge of the middle part of the crucible, while the titanium-tin master alloy is placed at the center of the middle part of the crucible. The vacuum induction levitation melting furnace is used to repeat melting 2 times, and finally an alloy ingot is obtained by casting;

[0076] S320, deformation processing

[0077] Put the alloy ingot obtained in step S310 into a vacuum heat treatment furnace, evacuate to 1.5x10 -3 Pa, then heat it in the furnace at a heating rate of 5 ºC / min to a temperature T1 of 1150 ºC, keep it warm for a time t1 of 2 h, and then air-cool it to room temperature. Subsequently, put the alloy ingot into a general heat treatment furnace at a temperature T2 of 680 ºC and keep it warm for a time t2 of 5 min. After taking it out and performing multi-pass rolling deformation processing, the deformation amount of each pass is 8%, and the cumulative deformation amount is about 80%. Finally, an alloy primary plate is obtained;

[0078] S330, annealing treatment

[0079] Put the alloy primary plate obtained in step S320 into a heat treatment furnace at a temperature T3 of 780 ºC and keep it warm for a time t3 of 20 min. Take it out and quickly cool it in water. Subsequently, polish its surface to obtain a high-performance titanium alloy material;

[0080] As Figure 2 shown by curve 3 in, a high-performance titanium alloy with strong uniform deformation ability provided in this Example 1 has mechanical property indexes of uniform elongation ε uni of about 36%, fracture elongation of about 49%, yield strength of about 668 MPa, tensile strength of about 818 MPa, and the characteristic peak value of work hardening rate of about 1.4 GPa (as Figure 3 shown by curve 3 in). From Figure 4 and Figure 5 the port morphology of the alloy is clearly visible. The fracture mode of the alloy is ductile fracture. The macroscopic fracture presents a cup-cone shape and consists of a crack formation area, a crack propagation area and a shear fracture area; a large number of dimpled structures are contained in the microscopic fracture. It can be seen that the high-performance titanium alloy provided by the present invention has excellent comprehensive mechanical properties such as strong uniform deformation ability, ultra-high plasticity and good work hardening ability, and has production promotion and potential application prospects in the room-temperature processing of complex components such as aviation, aerospace and ships.

[0081] According to the design principle of titanium alloy composition and based on the stress-induced response toughening mechanism of the alloy metastable β phase, the present invention has developed a high-performance titanium alloy with strong uniform deformation ability and its preparation method, effectively solving the key technical problems of low uniform elongation rate of traditional titanium alloys and being unsuitable for room-temperature stamping forming, and having production promotion and potential application prospects in the room-temperature processing of complex components such as aviation, aerospace, and ships.

[0082] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-performance titanium alloy with strong uniform deformation ability, characterized in that, The alloy consists of the following elements by mass percentage: Cr is 4.8 - 5.8%, Mo is 1.2 - 2.2%, Sn is 1.5 - 2.5%, Zr is 0.6 - 1.2%, and the balance is Ti and inevitable impurity elements; The uniform elongation of the alloy is ≥30%, the fracture elongation is 40% - 55%, the yield strength is 600 MPa - 800 MPa, the tensile strength is 800 MPa - 980 MPa, and the peak value of the work hardening rate is greater than 1 GPa.

2. The high-performance titanium alloy with strong uniform deformation ability as described in claim 1, characterized in that: The alloy is within d the parameter range in the electronic titanium alloy design theory is 2.391 ≤ ≤ 2.418, and the parameter range is 2.782 ≤ ≤ 2.

798.

3. A preparation method of a high-performance titanium alloy with strong uniform deformation ability as described in any one of claims 1 or 2, characterized in that, It mainly includes the following steps: (1) Melting and casting ingots Using titanium sponge, pure chromium sheets, pure molybdenum particles, zirconium sponge and titanium-tin master alloy as raw materials and proportioning according to the set alloy mass percentage, and then placing the proportioned raw materials in the cold crucible of a vacuum induction levitation melting furnace, and using the vacuum induction levitation melting furnace to melt repeatedly to pour and obtain alloy ingots; (2) Deformation processing Put the alloy ingot in step (1) into a vacuum heat treatment furnace, heat it to temperature T1 with the vacuum heat treatment furnace and keep it for time t1, then air-cool it to room temperature, and then put the alloy ingot into a common heat treatment furnace at temperature T2 for time t2, take it out and carry out multi-pass rolling deformation processing to obtain primary alloy sheets; (3) Annealing treatment Put the primary alloy sheets obtained in step (2) into a common heat treatment furnace at temperature T3 for time t3, take it out and put it into a brine solution at room temperature for rapid cooling, and then polish its surface to obtain a high-performance titanium alloy material.

4. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: When the raw materials in step (1) are first melted in the vacuum induction levitation melting furnace, place the titanium sponge at the upper and lower parts of the cold crucible, mix the pure chromium sheets, pure molybdenum particles and zirconium sponge and place them at the edge of the middle part of the crucible, and place the titanium-tin master alloy at the center of the middle part of the crucible.

5. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In step (1), the raw materials placed in the cold crucible are repeatedly melted 2 - 3 times by using the vacuum induction levitation melting furnace.

6. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In step (2), the temperature T1 is 1050 °C - 1200 °C, and the time t1 is 2 h - 4 h; the temperature T2 is 600 °C - 760 °C, and the time t2 is 5 min - 60 min.

7. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In the step (2), the heating rate of the vacuum heat treatment furnace is 5°C / min - 10°C / min, and the vacuum degree is 1.0x10 -3 Pa - 3.5x10 -3 Pa.

8. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In step (2), the deformation amount of each pass of rolling deformation is 2% - 10%, and the cumulative deformation amount is ≥80%.

9. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In step (3), the temperature T3 is 650 °C - 860 °C, and the time t3 is 5 min - 120 min.

10. The preparation method of the high-performance titanium alloy with strong uniform deformation ability according to claim 3, characterized in that: In step (3), the brine solution ratio is NaCl: 8 - 12 wt.%, and the balance is water.

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