A method for improving the impact resistance and blast resistance of titanium alloys

Abstract

The application discloses a method for improving the impact resistance and explosion resistance of a titanium alloy. The titanium alloy plate has an elongated macrostructure feature, the basal plane pole points of which are uniformly distributed in a plane perpendicular to the impact direction, and the overall {10-10} and {11-20} crystal face pole patterns have a uniform distribution feature. The preparation process comprises the following steps: forging blank selection, forging blank heating and pretreatment, square shaping, spread forming, multi-fire rolling, and solid solution aging heat treatment. According to whether the original forging blank has a specified organizational form, different high-temperature heating, holding and shaping systems are used to control and stabilize the macrostructure, alpha and beta two-phase structure and texture distribution of the plate. The titanium alloy plate prepared by the above process has good organizational stability, texture uniformity and impact damage resistance.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy forging technology, and specifically relates to a method for improving the impact resistance and explosion resistance of titanium alloys. Background Technology

[0002] Titanium alloy sheets possess a comprehensive set of advantages, including low density, high specific strength, excellent corrosion resistance, good heat resistance, and high damage tolerance, making them highly valuable in lightweight structural design. Compared to traditional structural materials such as steel and nickel-based alloys, titanium alloy sheets can significantly reduce structural mass while maintaining load-bearing capacity, and exhibit excellent corrosion resistance, fatigue resistance, and creep resistance in marine, aerospace, and high-temperature service environments. Furthermore, titanium alloy sheets have good weldability, formability, and component integration potential, allowing for the fabrication of complex thin-walled structures through processes such as rolling, hot forming, superplastic forming / diffusion bonding, and laser welding. Therefore, titanium alloy sheets are widely used in aero-engine casings, aircraft skin and thermal insulation structures, missile and spacecraft shells, corrosion-resistant components for ships and deep-sea equipment, chemical heat exchangers, medical implants, and high-end lightweight protective structures, making them crucial metallic structural materials for achieving high performance, lightweight design, and long service life.

[0003] As the application of titanium alloy thin plates in aerospace, naval and marine equipment, lightweight protective structures, and high-speed transportation equipment continues to expand, their service environment is gradually extending from traditional static or quasi-static load conditions to complex dynamic load and extreme load conditions. In actual service, thin plate structures not only need to withstand tensile, bending, vibration, and fatigue loads, but may also be subjected to transient high-energy impacts such as foreign object impacts, high-speed debris impacts, shock waves, and explosive loads. These extreme loads typically feature high strain rates, short loading times, high local energy densities, and rapid damage evolution, easily inducing local plastic instability, adiabatic shear, rapid crack propagation, perforation, and even overall failure of the thin plate. Therefore, relying solely on the high specific strength and corrosion resistance of titanium alloy thin plates is no longer sufficient to fully meet the structural safety and reliability requirements under complex service environments.

[0004] Against this backdrop, improving the impact and blast resistance of titanium alloy sheets has become an important direction for their further engineering applications. An ideal impact / blast resistant titanium alloy sheet should not only possess high strength to resist local indentation and penetration under impact loads, but also good plasticity, toughness, and strain hardening capacity to absorb and dissipate impact energy during high-speed deformation, delaying crack initiation and propagation. Furthermore, the sheet material needs to maintain stable deformation coordination under high strain rate conditions to avoid early failure due to uneven microstructure, local softening, or strain concentration. Therefore, it is necessary to construct a titanium alloy sheet system that synergistically enhances strength, plasticity, toughness, and energy absorption capacity by focusing on microstructure control, heat treatment regime optimization, and sheet forming processes, in order to meet the demands of aerospace, marine equipment, and protective structures for lightweight, high-safety service materials. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method for improving the impact resistance and explosion resistance of titanium alloys. The specific technical solution is as follows:

[0006] A method for improving the impact resistance and explosion resistance of titanium alloys involves controlling the macro-region structure and texture distribution of the titanium alloy sheet to form a slender strip-shaped macro-region structure on a cross-section parallel to the impact direction. The IPF diagram shows obvious slender strip-shaped orientation macro-region characteristics, and the {0001} basal plane poles are uniformly distributed in a plane perpendicular to the impact direction, while the {10-10} and {11-20} crystal plane poles are uniformly distributed relative to the sample coordinate system.

[0007] The preferred embodiment of the method for improving the impact resistance and explosion resistance of titanium alloy is that the titanium alloy sheet comprises, by mass percentage: Al: 5.5 ~ 6.5%, Mo + Nb: 3.5 ~ 4.5%, wherein Nb ≤ 3.5%, Zr + Sn: 1.5 ~ 3.0%, with the balance being Ti and unavoidable impurities.

[0008] A preparation process for improving the impact resistance and explosion resistance of titanium alloys includes the following steps:

[0009] When a titanium alloy forging billet with a specified microstructure is used as the original billet, steps S1-1, S2-1, S3, S4, S5 and S6 are performed sequentially.

[0010] When a titanium alloy forging billet with a specified microstructure is not used as the original billet, steps S1-2, S2-2, S3, S4, S5 and S6 are performed sequentially.

[0011] The specific steps are as follows:

[0012] S1-1: Selection of forging blanks with specified microstructure;

[0013] Based on the thickness, width, length of the target plate and the dimensional loss during subsequent hot working, trimming, grinding and heat treatment, select a titanium alloy forging billet of suitable size as the original billet;

[0014] The composition of the titanium alloy forging billet should be: Al: 5.5 ~ 6.5%, Mo + Nb: 3.5 ~ 4.5%, of which Nb ≤ 3.5%, Zr + Sn: 1.5 ~ 3.0%, with the balance being Ti and unavoidable impurities.

[0015] The titanium alloy forging blank has slender macro-region characteristics and crystalline structure. <0001> The orientation is relatively uniformly distributed within the RD-TD plane, exhibiting good tissue stability and retaining certain genetic characteristics.

[0016] The term "forging blank of suitable size" refers to a forging blank whose volume is 115% to 135% of the volume of the finished sheet metal.

[0017] Before the forging billet enters the subsequent heating and shaping process, the surface of the forging billet is cleaned to remove surface oxide scale, oil stains, folds, cracks and obvious indentation defects.

[0018] The process involves removing surface oxide scale, oil stains, folds, cracks, and obvious indentation defects, with a single-sided removal thickness of 2 to 4 mm.

[0019] S1-2: Selection of forging blanks without specified microstructure;

[0020] Based on the thickness, width, and length of the target plate, as well as the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging billet of suitable size is selected as the original billet.

[0021] The composition of the titanium alloy forging billet should be: Al: 5.5 ~ 6.5%, Mo + Nb: 3.5 ~ 4.5%, of which Nb ≤ 3.5%, Zr + Sn: 1.5 ~ 3.0%, with the balance being Ti and unavoidable impurities.

[0022] The titanium alloy forging blank does not possess the characteristics of slender macro-regions or crystalline structures. <0001> The orientation is relatively uniformly distributed within the forging blank, the microstructure is relatively stable, and the genetic characteristics are relatively low.

[0023] The "forging blank of suitable size" refers to a forging blank whose volume is 120% to 140% of the volume of the finished sheet metal.

[0024] Before the forging billet enters the subsequent heating and shaping process, the surface of the forging billet is cleaned to remove surface oxide scale, oil stains, folds, cracks and obvious indentation defects.

[0025] The process involves removing surface oxide scale, oil stains, folds, cracks, and obvious indentation defects, with a single-sided removal thickness of 2 to 4 mm.

[0026] S2-1: Heating and pretreatment of forging blanks with specified microstructure;

[0027] The titanium alloy forging billet obtained from S1-1 is heated to 60-80°C above the phase transformation point and held for 20-30 minutes, and then transferred to a forging press for high-temperature shaping.

[0028] The heating method is furnace heating, and the preferred heating rate is 5 to 10 °C per minute.

[0029] Before shaping the forged disc, its corners and edges need to be chamfered or rounded.

[0030] The chamfer radius is 10 ~ 25 mm;

[0031] The high-temperature forming process requires controlling the single-pass reduction to be 5% to 8%, the total deformation in a single pass to be 10% to 20%, and the final forging temperature to be no lower than the β phase transformation point temperature.

[0032] S2-2: Heating and pretreatment of forgings without specified microstructure;

[0033] The titanium alloy forging billet obtained in S1-2 is heated to 100-120°C above the phase transformation point and held for 2-3 hours, and then transferred to a forging press for high-temperature shaping.

[0034] The heating method is furnace heating, and the preferred heating rate is 5 to 10 °C per minute.

[0035] Before shaping the forged disc, its corners and edges need to be chamfered or rounded.

[0036] The chamfer radius is 10 ~ 25 mm;

[0037] The high-temperature forming process requires controlling the single-pass reduction to be 15% to 18%, the total deformation in a single pass to be 30% to 36%, and the final forging temperature to be no less than 20°C above the β phase transformation point.

[0038] S3: Square shaping;

[0039] The forging billet treated with S2-1 or S2-2 is heated to 20-60°C below the β phase transformation point and held for 2-3 hours. Then it is transferred to a forging press for pressing and shaping to obtain a titanium alloy square block.

[0040] The heating method is furnace heating, and the preferred heating rate is 5 to 10 °C per minute.

[0041] The pressing and shaping process begins by lightly pressing along any side of the forging billet to make the upper and lower surfaces of the forging billet flat; then, pressing is performed multiple times along the periphery of the forging billet so that the forging billet gradually forms an approximately square or approximately rectangular billet when viewed from the ND direction.

[0042] The reduction per pass is 5% to 10%, and the total deformation during the compression and shaping process is 10% to 20%.

[0043] The final forging temperature of the square forming process shall not be lower than 850℃.

[0044] S4: Widening and shaping;

[0045] The titanium alloy square block obtained from S3 is heated to 10-40℃ below the β phase transformation point and held for 2-3 hours. It is then widened and deformed by multi-pass transverse pressing to finally obtain a widened titanium alloy plate with increased width, reduced thickness and uniform deformation.

[0046] Before widening, the square blocks are pre-compressed and shaped in 1 to 2 passes, with a single pass reduction rate of 3% to 8%.

[0047] The billet is widened by transverse pressing, and the widening is carried out along the TD direction. The pressing direction is the ND direction. The single-pass pressing rate is 8% to 15%, and the total deformation is 30% to 32%.

[0048] The billet is widened by a single feed of 200-300mm, and the feed rate is required to be 3-8s / time for stretching.

[0049] The end temperature of a single pass in the widening process should not be lower than 850℃. If the temperature is lower than 850℃, the plate should be placed back in the furnace and heated to 10-40℃ below the β phase transformation point before widening continues.

[0050] S5: Multi-pass rolling;

[0051] The titanium alloy sheet obtained from S4 is heated to 40-80℃ below the β phase transformation point and held for 2-3 hours. The thickness of the sheet is controlled by a multi-fire rolling method to obtain the titanium alloy sheet.

[0052] The multi-pass rolling process consists of 2 to 5 passes. After each pass, the plate is returned to the furnace to be heated to 40 to 80°C below the β phase transformation point and held for 0.5 to 1 hour before continuing rolling.

[0053] Each rolling process includes 2 to 5 passes of deformation, with a single pass reduction rate of 5% to 10% and a cumulative reduction rate of 20% to 25% per rolling pass.

[0054] The final rolling temperature for each heat treatment shall not be lower than 860℃;

[0055] The rolling process adopts a unidirectional rolling method. When the rolling passes are greater than 3 times, a cross rolling method is adopted.

[0056] S6: Heat treatment;

[0057] The titanium alloy sheet obtained from S5 is heated to 50-80℃ below the β phase transformation point and held for 2-4 hours for solution treatment, followed by air cooling to room temperature; then heated to 600-700℃ and held for 2-4 hours for aging treatment, followed by air cooling to room temperature, finally obtaining a titanium alloy sheet with excellent impact resistance.

[0058] The titanium alloy sheet needs to undergo surface treatment and oxide scale removal after solution aging.

[0059] The titanium alloy sheets obtained by this method are used to manufacture load-bearing skins, fuselage frames, compartment panels, stiffening ribs, webs, connecting plates, thermal insulation load-bearing plates, and locally damaged structural panels for aerospace vehicles. These sheets are characterized by low density, high specific strength, good formability, strong crack propagation resistance, and excellent overall fatigue performance, making them suitable for thin-walled or medium-thick-walled structural components requiring a balance between weight reduction, load-bearing capacity, and safety margin. Compared to conventional titanium alloy sheets, the alloy sheets of this invention maintain better plasticity and damage tolerance when subjected to in-plane tension, bending deformation, localized impact, and cyclic loading, which is beneficial for improving the reliability and service life of components in complex service environments. In terms of operating conditions, the titanium alloy sheets proposed in this invention exhibit excellent impact load resistance and blast impact resistance in the ND direction, showing broad application prospects.

[0060] Beneficial effects

[0061] (1) By limiting the finished titanium alloy material to have a slender strip-shaped macro-region feature and controlling the uniform distribution of the polarity of the {0001} basal plane in a plane perpendicular to the impact direction, while ensuring that the {10-10} and {11-20} orientations are uniformly distributed, the anisotropy of mechanical properties caused by strong texture and single orientation concentration in the material can be effectively reduced, and the rapid propagation of cracks along specific crystal planes or specific orientation regions under impact loads can be avoided. This microstructure enables α grains with different orientations to synergistically initiate basal, cylindrical, and conical slip during deformation, improving local plastic coordination and crack propagation resistance, thereby improving the toughness stability and strength-toughness matching of the finished titanium alloy in the impact direction.

[0062] (2) Through the synergistic regulation of the above-mentioned structure and texture, the titanium alloy sheet prepared by the present invention has excellent impact load resistance and explosion impact resistance in the ND direction, and is suitable for thin-walled or medium-thick-walled structural components that are subjected to explosion impact loads. The combination of slender strip-shaped macro-regions and uniform orientation distribution of weak texture is beneficial to improving impact absorption capacity and service reliability while maintaining high strength.

[0063] (3) By rationally selecting the size of the forging billet, it is possible to ensure the allowance for subsequent upsetting, rolling, trimming and grinding, while avoiding the finished product size being too small due to the original billet volume being too small, and also avoiding the deformation penetration being insufficient, the central structure being difficult to break and the processing cost being increased due to the billet volume being too large. Pre-treatment of the forging billet surface is beneficial to reduce the probability of surface cracks, edge cracks and folding defects during hot working.

[0064] (4) The method of the present invention is applicable to a wider range of α+β titanium alloy composition systems. Through Mo+Nb composite strengthening and Zr+Sn synergistic addition, the microstructure characteristics of slender strip macro-region and uniform texture distribution can be obtained in different alloy systems, and it has good process universality.

[0065] (5) By heating and shaping above the β phase transformation point, the high-temperature deformation resistance of titanium alloy forging blanks can be significantly reduced, and the overall plasticity of the forging blanks can be improved. For forging blanks with a specified microstructure, the holding time is short to prevent recrystallization from significantly affecting the original microstructure; for forging blanks with a non-specified microstructure, the holding temperature is high and the holding time is long so that recrystallization can be used to make the initial β grains grow and improve the microstructure inheritance characteristics.

[0066] (6) The square forming process obtains a square block with regular shape and stable size without significantly changing or destroying the original microstructure of the forging billet. The widening direction is selected as the TD direction, which forms a reasonable cross deformation path with the subsequent rolling deformation along the RD direction, avoiding excessive elongation of the microstructure and excessive concentration of texture caused by continuous deformation of the billet in a single direction.

[0067] (7) The multi-pass rolling process distributes the total rolling deformation to multiple passes to complete the process step by step. The first three passes use a unidirectional rolling method to make the plate form a long and thin strip macro-region structure that extends along the rolling direction and has a controllable distribution.

[0068] (8) Solution treatment and aging treatment can further promote the homogenization of the microstructure and reduce the residual stress of rolling while retaining the slender strip-shaped macro-region microstructure and controllable texture characteristics formed by rolling. After solution aging treatment, surface treatment and oxide scale removal can eliminate the surface oxide layer and oxygen enrichment layer formed during heat treatment, thereby improving the surface quality of the plate.

[0069] Compared with the prior art, the present invention has the following advantages:

[0070] This invention addresses the challenge of synergistically controlling the macro-region microstructure, grain orientation, and impact properties in titanium alloy sheets by establishing a stable and controllable microstructure regulation method. Existing titanium alloy sheets often exhibit problems during hot working, such as pronounced local microstructure inheritance, uneven deformation, uncontrollable macro-region morphology, and localized texture concentration, leading to significant fluctuations in impact properties at different locations or sampling directions. This invention addresses this issue by synergistically controlling the billet geometry, deformation path, deformation amount per heat pass, and subsequent microstructure stabilization process. This results in a more uniform, continuous, and controllable deformation microstructure within the sheet, thereby improving the consistency of the sheet's microstructure and properties.

[0071] The titanium alloy sheet obtained by this invention exhibits a distinct elongated macro-region microstructure, which is well-matched with the impact sampling direction. The polarity of its {0001} basal plane is relatively uniformly distributed in the plane perpendicular to the impact direction, the maximum texture density is within an appropriate range, and the {10-10} and {11-20} orientations are generally uniformly distributed, indicating that no excessively strong local orientation aggregation has formed in the sheet. This microstructure and texture state helps reduce the tendency for cracks to propagate rapidly along locally strong textured areas, mitigates the impact performance instability caused by abnormal macro-regions or orientation concentrations, thereby improving the impact resistance and service reliability of the titanium alloy sheet.

[0072] Furthermore, this invention, while ensuring dimensional accuracy and shape stability of the sheet metal, also considers microstructure control, texture management, and surface quality improvement. It can reduce the adverse effects of residual stress, oxide scale, and surface oxygen-rich layers during hot working and heat treatment on material properties. The titanium alloy sheet metal prepared in this way exhibits clear microstructure characteristics, suitable texture distribution, good performance stability, and excellent impact resistance, making it suitable for manufacturing titanium alloy sheet metal with high requirements for impact toughness, microstructure uniformity, and service reliability. Attached Figure Description

[0073] Figure 1 A schematic diagram illustrating the characteristics of a titanium alloy with excellent impact and explosion resistance;

[0074] Figure 2 The images shown are SEM images, IPF images, and pole figures of the plate material obtained in Example 1.

[0075] Figure 3 The images shown are SEM images, IPF images, and pole figures of the plate material obtained in Example 2.

[0076] Figure 4 Metallographic image of the plate obtained in Example 3;

[0077] Figure 5 The image shows the metallographic structure of the sheet material obtained in Example 4. Detailed Implementation

[0078] The following will be combined with the appendix Figure 1-5 The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0079] It should be noted that: Examples 1 and 2 are processed using forging blanks with a specified microstructure, and their preparation process steps M1 are S1-1, S2-1, S3, S4, S5, S6; Examples 3 and 4 are processed using forging blanks without a specified microstructure, and their preparation process steps M2 are S1-2, S2-2, S3, S4, S5, S6.

[0080] Furthermore, in order to facilitate a detailed description of the process proposed in this invention, the embodiments and comparative examples of this invention all use Ti-6Al-4Mo-1Zr-1Sn as the research object, with a phase transition point of 990℃.

[0081] Example 1

[0082] A preparation process for improving the impact resistance and explosion resistance of titanium alloys includes the following steps:

[0083] S1-1: Selection of forging billet dimensions;

[0084] Based on the thickness, width, and length requirements of the target sheet, and taking into account the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging blank of suitable size is selected as the initial blank. This forging blank should possess slender, elongated macro-region characteristics and crystal structure... <0001> The orientation is relatively uniformly distributed within the RD-TD plane, resulting in good structural stability and the retention of certain genetic characteristics. Appropriate dimensions refer to the forging billet volume being controlled to 115% of the required finished plate volume. Before the forging billet enters the subsequent heating and shaping process, its surface should be cleaned to remove defects such as oxide scale, oil stains, folds, cracks, and obvious indentations. The thickness removed on one side should be controlled to 2mm.

[0085] S2-1: Heating and pretreatment of forging billets;

[0086] The titanium alloy forging billet obtained in S1-1 is heated in the furnace to 60°C above the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 20 minutes, it is transferred to a forging press for high-temperature forming. Before forming, the edges and corners of the forging billet are chamfered or rounded, with a chamfer radius controlled at 10mm. During the high-temperature forming process, the single-pass reduction is controlled at 5%, the total deformation per pass is controlled at 20%, and the final forging temperature is not lower than the β phase transformation point temperature.

[0087] S3: Square shaping;

[0088] The material obtained in S2-1 was heated in the furnace to 20°C below the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 2 hours, it was transferred to a forging press for square forming to obtain a square titanium alloy block. During the square forming process, light pressure was first applied along any side of the forging billet to flatten the upper and lower surfaces. Then, multiple pressures were applied along the periphery of the forging billet to gradually form an approximately square or rectangular billet when viewed from the ND direction. The reduction in each pass was controlled at 5%, the total deformation during the square forming process was controlled at 20%, and the final forging temperature was not lower than 850°C.

[0089] S4: Widening and shaping;

[0090] The titanium alloy square block obtained in S3 was heated to 10°C below the β phase transformation point and held for 2 hours. Then, it was widened and deformed using a multi-pass transverse pressing method, ultimately obtaining a titanium alloy widened plate with increased width, reduced thickness, and uniform deformation. Before widening, the square block underwent one pass of pre-pressing, with a single-pass reduction rate controlled at 3%. Widening was then performed along the TD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 8%, and a total deformation controlled at 32%. During widening, the single feed rate was controlled at 200mm, and the feed time was controlled at 3s. If the estimated end temperature of a single pass was below 850°C, the plate needed to be placed back in the furnace and heated to 10°C below the β phase transformation point before continuing the widening deformation.

[0091] S5: Multi-pass rolling;

[0092] The titanium alloy sheet obtained in S4 was heated to 40°C below the β phase transformation point and held for 2 hours. The sheet thickness was then controlled using a multi-pass rolling process to obtain the titanium alloy sheet. The multi-pass rolling was controlled to be 2 passes. After each pass, the sheet was returned to the furnace to be heated to 40°C below the β phase transformation point and held for 0.5 hours before continuing rolling. Unidirectional rolling was preferred during the rolling process. Each pass included 5 deformation passes, with a single-pass reduction rate controlled at 5%, a cumulative reduction rate controlled at 25%, and a final rolling temperature of not less than 860°C per pass.

[0093] S6: Heat treatment;

[0094] The titanium alloy sheet obtained in S5 was heated to 50°C below the β phase transformation point, held at that temperature for 2 hours, and then subjected to solution treatment, followed by air cooling to room temperature. The sheet was then heated to 600°C, held at that temperature for 2 hours, and then subjected to aging treatment, followed by air cooling to room temperature, ultimately yielding a titanium alloy sheet with excellent impact resistance. After the solution and aging treatments, the sheet underwent surface treatment and oxide scale removal.

[0095] Example 2

[0096] A preparation process for improving the impact resistance and explosion resistance of titanium alloys includes the following steps:

[0097] S1-1: Selection of forging billet dimensions;

[0098] Based on the thickness, width, and length requirements of the target sheet, and taking into account the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging blank of suitable size is selected as the initial blank. This forging blank should possess slender, elongated macro-region characteristics and crystal structure... <0001> The orientation is relatively uniformly distributed within the RD-TD plane, resulting in good structural stability and the retention of certain genetic characteristics. Appropriate dimensions refer to the forging billet volume being controlled to 135% of the required finished plate volume. Before the forging billet enters the subsequent heating and shaping process, its surface should be cleaned to remove defects such as oxide scale, oil stains, folds, cracks, and obvious indentations. The thickness removed on one side should be controlled to 4mm.

[0099] S2-1: Heating and pretreatment of forging billets;

[0100] The titanium alloy forging billet obtained in S1-1 is heated in the furnace to 60-80℃ above the β phase transformation point, with a heating rate controlled at 10℃ / min. After holding at this temperature for 30 minutes, it is transferred to a forging press for high-temperature shaping. Before shaping, the edges and corners of the forging billet are chamfered or rounded, with the chamfer radius controlled at 25mm. During the high-temperature shaping process, the single-pass reduction is controlled at 8%, the total deformation per pass is controlled at 16%, and the final forging temperature is not lower than the β phase transformation point temperature.

[0101] S3: Square shaping;

[0102] The material obtained in S2-1 was heated in the furnace to 60°C below the β phase transformation point at a rate of 10°C / min. After holding at this temperature for 3 hours, it was transferred to a forging press for square forming to obtain a square titanium alloy block. During the square forming process, light pressure was first applied along any side of the forging billet to make the upper and lower surfaces of the billet tend to be flat. Then, the edges were pressed multiple times along the periphery of the forging billet, so that the billet gradually formed an approximately square or approximately rectangular billet when viewed from the ND direction. The reduction in each pass was controlled at 10%, the total deformation in the square forming process was controlled at 20%, and the final forging temperature was not lower than 850°C.

[0103] S4: Widening and shaping;

[0104] The titanium alloy square block obtained in S3 was heated to 40°C below the β phase transformation point and held for 3 hours. Then, it was widened and deformed using a multi-pass transverse pressing method, ultimately obtaining a titanium alloy widened plate with increased width, reduced thickness, and uniform deformation. Before widening, the square block underwent two passes of pre-pressing, with a single-pass reduction rate controlled at 8%. Widening was then performed along the TD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 15%, and a total deformation controlled at 30%. During widening, the single feed rate was controlled at 300 mm, and the feed time was controlled at 8 seconds. If the estimated end temperature of a single pass was below 850°C, the plate needed to be placed back in the furnace and heated to 10-40°C below the β phase transformation point before continuing the widening deformation.

[0105] S5: Multi-pass rolling;

[0106] The titanium alloy sheet obtained in S4 is heated to 80°C below the β phase transformation point and held for 3 hours. The sheet thickness is then controlled using a multi-pass rolling method to obtain the titanium alloy sheet. The multi-pass rolling is controlled to be 5 passes. After each pass, the sheet is returned to the furnace to be heated to 80°C below the β phase transformation point and held for 1 hour before continuing rolling. Unidirectional rolling is preferred during the rolling process; when the number of rolling passes exceeds 3, cross rolling is used. Each rolling pass includes 5 deformation passes, with a single-pass reduction rate controlled at 10%, a cumulative reduction rate controlled at 20%, and a final rolling temperature of not less than 860°C per pass.

[0107] S6: Heat treatment;

[0108] The titanium alloy sheet obtained in S5 was heated to 80°C below the β phase transformation point, held at that temperature for 4 hours, and then subjected to solution treatment, followed by air cooling to room temperature. The sheet was then heated to 700°C, held at that temperature for 4 hours, and then subjected to aging treatment, followed by air cooling to room temperature, ultimately yielding a titanium alloy sheet with excellent impact resistance. After the solution and aging treatments, the sheet underwent surface treatment and oxide scale removal.

[0109] Example 3

[0110] A preparation process for improving the impact resistance and explosion resistance of titanium alloys includes the following steps:

[0111] S1-2: Selection of forging billet dimensions;

[0112] Based on the thickness, width, and length requirements of the target sheet, and taking into account the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging blank of suitable size was selected as the initial blank. This forging blank does not exhibit elongated macro-region characteristics, and the crystal structure... <0001> The orientation is relatively uniformly distributed within the forging blank, resulting in good structural stability and weak heritability. Appropriate dimensions refer to the forging blank volume being controlled to 120% of the required finished plate volume. Before the forging blank enters the subsequent heating and shaping process, the surface of the forging blank is cleaned to remove defects such as oxide scale, oil stains, folds, cracks, and obvious indentations. The thickness removed on one side is controlled to 2mm.

[0113] S2-2: Heating and pretreatment of forging billets;

[0114] The titanium alloy forging billet obtained in S1-2 is heated in the furnace to 100°C above the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 2 hours, it is transferred to a forging press for high-temperature forming. Before forming, the edges and corners of the forging billet are chamfered or rounded, with a chamfer radius controlled at 10mm. During the high-temperature forming process, the single-pass reduction is controlled at 15%, the total deformation per pass is controlled at 30%, and the final forging temperature is not lower than 20°C above the β phase transformation point.

[0115] S3: Square shaping;

[0116] The material obtained in S2-2 was heated in the furnace to 20°C below the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 2 hours, it was transferred to a forging press for square forming to obtain a square titanium alloy block. During the square forming process, light pressure was first applied along any side of the forging billet to flatten the upper and lower surfaces. Then, multiple pressures were applied along the periphery of the forging billet to gradually form an approximately square or rectangular billet when viewed from the ND direction. The reduction in each pass was controlled at 5%, the total deformation during the square forming process was controlled at 20%, and the final forging temperature was not lower than 850°C.

[0117] S4: Widening and shaping;

[0118] The titanium alloy square block obtained in S3 was heated to 10°C below the β phase transformation point and held for 2 hours. Then, it was widened and deformed using a multi-pass transverse pressing method, ultimately obtaining a titanium alloy widened plate with increased width, reduced thickness, and uniform deformation. Before widening, the square block underwent one pass of pre-pressing, with a single-pass reduction rate controlled at 3%. Widening was then performed along the TD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 8%, and a total deformation controlled at 32%. During widening, the single feed rate was controlled at 200mm, and the feed time was controlled at 3s. If the estimated end temperature of a single pass was below 850°C, the plate needed to be placed back in the furnace and heated to 10°C below the β phase transformation point before continuing the widening deformation.

[0119] S5: Multi-pass rolling;

[0120] The titanium alloy sheet obtained in S4 was heated to 40°C below the β phase transformation point and held for 2 hours. The sheet thickness was then controlled using a multi-pass rolling process to obtain the titanium alloy sheet. The multi-pass rolling was controlled to be 2 passes. After each pass, the sheet was returned to the furnace to be heated to 40°C below the β phase transformation point and held for 0.5 hours before continuing rolling. Unidirectional rolling was preferred during the rolling process. Each pass included 5 deformation passes, with a single-pass reduction rate controlled at 5%, a cumulative reduction rate controlled at 25%, and a final rolling temperature of not less than 860°C per pass.

[0121] S6: Heat treatment;

[0122] The titanium alloy sheet obtained in S5 was heated to 50°C below the β phase transformation point, held at that temperature for 2 hours, and then subjected to solution treatment, followed by air cooling to room temperature. The sheet was then heated to 600°C, held at that temperature for 2 hours, and then subjected to aging treatment, followed by air cooling to room temperature, ultimately yielding a titanium alloy sheet with excellent impact resistance. After the solution and aging treatments, the sheet underwent surface treatment and oxide scale removal.

[0123] Example 4

[0124] A preparation process for improving the impact resistance and explosion resistance of titanium alloys includes the following steps:

[0125] S1-2: Selection of forging billet dimensions;

[0126] Based on the thickness, width, and length requirements of the target sheet, and taking into account the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging blank of suitable size was selected as the initial blank. This forging blank does not exhibit elongated macro-region characteristics, and the crystal structure... <0001> The orientation is relatively uniformly distributed within the forging blank, resulting in good structural stability and weak heritability. Appropriate dimensions refer to the forging blank volume being controlled to 140% of the required finished plate volume. Before the forging blank enters the subsequent heating and shaping process, the surface of the forging blank is cleaned to remove defects such as oxide scale, oil stains, folds, cracks, and obvious indentations. The thickness removed on one side is controlled to 4mm.

[0127] S2-2: Heating and pretreatment of forging billets;

[0128] The titanium alloy forging billet obtained in S1-2 was heated in the furnace to 120°C above the β phase transformation point at a rate of 10°C / min. After holding at this temperature for 3 hours, it was transferred to a forging press for high-temperature forming. Before forming, the edges and corners of the forging billet were chamfered or rounded, with a chamfer radius controlled at 25mm. During the high-temperature forming process, the single-pass reduction was controlled at 18%, the total deformation per pass was controlled at 36%, and the final forging temperature was not lower than 20°C above the β phase transformation point.

[0129] S3: Square shaping;

[0130] The material obtained in S2-2 was heated in the furnace to 60°C below the β phase transformation point at a rate of 10°C / min. After holding at this temperature for 3 hours, it was transferred to a forging press for square forming to obtain a square titanium alloy block. During the square forming process, light pressure was first applied along any side of the forging billet to make the upper and lower surfaces of the billet tend to be flat. Then, the edges were pressed multiple times along the periphery of the forging billet, so that the billet gradually formed an approximately square or approximately rectangular billet when viewed from the ND direction. The reduction in each pass was controlled at 10%, the total deformation in the square forming process was controlled at 20%, and the final forging temperature was not lower than 850°C.

[0131] S4: Widening and shaping;

[0132] The titanium alloy square block obtained in S3 was heated to 40°C below the β phase transformation point and held for 3 hours. Then, it was widened and deformed using a multi-pass transverse pressing method, ultimately obtaining a titanium alloy widened plate with increased width, reduced thickness, and uniform deformation. Before widening, the square block underwent two passes of pre-pressing, with a single-pass reduction rate controlled at 8%. Widening was then performed along the TD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 15%, and a total deformation controlled at 30%. During widening, the single feed rate was controlled at 300 mm, and the feed time was controlled at 8 seconds. If the estimated end temperature of a single pass was below 850°C, the plate needed to be placed back in the furnace and heated to 10-40°C below the β phase transformation point before continuing the widening deformation.

[0133] S5: Multi-pass rolling;

[0134] The titanium alloy sheet obtained in S4 is heated to 80°C below the β phase transformation point and held for 3 hours. The sheet thickness is then controlled using a multi-pass rolling method to obtain the titanium alloy sheet. The multi-pass rolling is controlled to be 5 passes. After each pass, the sheet is returned to the furnace to be heated to 80°C below the β phase transformation point and held for 1 hour before continuing rolling. Unidirectional rolling is preferred during the rolling process; when the number of rolling passes exceeds 3, cross rolling is used. Each rolling pass includes 5 deformation passes, with a single-pass reduction rate controlled at 10%, a cumulative reduction rate controlled at 20%, and a final rolling temperature of not less than 860°C per pass.

[0135] S6: Heat treatment;

[0136] The titanium alloy sheet obtained in S5 was heated to 80°C below the β phase transformation point, held at that temperature for 4 hours, and then subjected to solution treatment, followed by air cooling to room temperature. The sheet was then heated to 700°C, held at that temperature for 4 hours, and then subjected to aging treatment, followed by air cooling to room temperature, ultimately yielding a titanium alloy sheet with excellent impact resistance. After the solution and aging treatments, the sheet underwent surface treatment and oxide scale removal.

[0137] Comparative Example 1

[0138] Compared with Example 1, in Comparative Example 1's "S1-1 Forging Billet Size Selection", a billet without slender macro-region characteristics and crystalline structure was used. <0001> The titanium alloy forging blank with relatively uniform orientation distribution, good microstructure stability, and low heritability is used as the original billet, which is consistent with S1-2 in Example 3. The specific implementation method is as follows:

[0139] S1-1: Selection of forging billet dimensions;

[0140] Based on the thickness, width, and length requirements of the target sheet, and taking into account the dimensional losses during subsequent hot working, trimming, grinding, and heat treatment, a titanium alloy forging blank of suitable size was selected as the initial blank. This forging blank does not exhibit elongated macro-region characteristics, and the crystal structure... <0001> The orientation is relatively uniformly distributed within the forging blank, resulting in good structural stability and weak heritability. Appropriate dimensions refer to the forging blank volume being controlled to 120% of the required finished plate volume. Before the forging blank enters the subsequent heating and shaping process, the surface of the forging blank is cleaned to remove defects such as oxide scale, oil stains, folds, cracks, and obvious indentations. The thickness removed on one side is controlled to 2mm.

[0141] Comparative Example 2

[0142] Compared with Example 1, in Comparative Example 2, “S2-1 Heating and Pretreatment of Forging Billet”, a pretreatment scheme with a relatively high temperature and a large deformation is adopted, which is consistent with the one described in Example 3, S2-2. The specific implementation method is as follows:

[0143] S2-1: Heating and pretreatment of forging billets;

[0144] The titanium alloy forging billet obtained in S1-1 is heated in the furnace to 100°C above the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 2 hours, it is transferred to a forging press for high-temperature forming. Before forming, the edges and corners of the forging billet are chamfered or rounded, with a chamfer radius controlled at 10mm. During the high-temperature forming process, the single-pass reduction is controlled at 15%, the total deformation per pass is controlled at 30%, and the final forging temperature is not lower than 20°C above the β phase transformation point.

[0145] Comparative Example 3

[0146] Compared with Example 3, in Comparative Example 3, “S2-2 Forging Billet Heating and Pretreatment”, a pretreatment scheme with relatively low temperature and small deformation is adopted, which is consistent with the one described in Example 1, S2-1. The specific implementation method is as follows:

[0147] S2-2: Heating and pretreatment of forging billets;

[0148] The titanium alloy forging billet obtained in S1-2 is heated in the furnace to 60°C above the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 20 minutes, it is transferred to a forging press for high-temperature forming. Before forming, the edges and corners of the forging billet are chamfered or rounded, with a chamfer radius controlled at 10mm. During the high-temperature forming process, the single-pass reduction is controlled at 5%, the total deformation per pass is controlled at 20%, and the final forging temperature is not lower than the β phase transformation point temperature.

[0149] Comparative Example 4

[0150] Compared with Example 1, in Comparative Example 4's "S3 compression shaping", a conventional deformation amount of approximately 30% to 35% is used. The specific implementation method is as follows:

[0151] S3: Square shaping;

[0152] The material obtained in S2-1 was heated in the furnace to 20°C below the β phase transformation point at a rate of 5°C / min. After holding at this temperature for 2 hours, it was transferred to a forging press for square forming to obtain a titanium alloy square block. During the square forming process, light pressure was first applied along any side of the forging billet to make the upper and lower surfaces of the billet tend to be flat. Then, the edges were pressed multiple times along the periphery of the forging billet, so that the billet gradually formed an approximately square or approximately rectangular billet when viewed from the ND direction. The reduction in each pass was controlled at 15%, the total deformation in the square forming process was controlled at 30%, and the final forging temperature was not lower than 850°C.

[0153] Comparative Example 5

[0154] Compared with Example 1, in the "S4 widening molding" of Comparative Example 5, widening is not carried out along the TD direction, but rather widening is carried out alternately along the TD and RD directions. The specific implementation method is as follows:

[0155] S4: Widening and shaping;

[0156] The titanium alloy square block obtained in S3 was heated to 10°C below the β phase transformation point and held for 2 hours. Then, it was widened and deformed using a multi-pass transverse pressing method, ultimately obtaining a titanium alloy widened plate with increased width, reduced thickness, and uniform deformation. Before widening, the square block underwent one pass of pre-pressing, with a single-pass reduction rate controlled at 3%. Widening was then performed along the TD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 8%, and a total deformation amount controlled at 16%. Next, widening was performed along the RD direction, with the pressing direction being the ND direction, a single-pass reduction rate controlled at 8%, and a total deformation amount controlled at 16%. During widening, the single feed rate was controlled at 200mm, and the feed time was controlled at 3s. If the estimated end temperature of a single pass was below 850°C, the plate needed to be placed back in the furnace and heated to 10°C below the β phase transformation point before continuing the widening deformation.

[0157] Comparative Example 6

[0158] Compared with Example 1, in Comparative Example 6, the first 3 passes of "S5 multi-pass rolling" also adopt a cross rolling method, and the specific implementation method is as follows:

[0159] S5: Multi-pass rolling;

[0160] The titanium alloy sheet obtained in S4 was heated to 40°C below the β phase transformation point and held for 2 hours. The sheet thickness was then controlled using a multi-pass rolling method to obtain the titanium alloy sheet. The multi-pass rolling was controlled to be 2 passes. After each pass, the sheet was returned to the furnace for reheating to 40°C below the β phase transformation point and held for 0.5 hours before continuing rolling. Cross-rolling was preferred in the rolling process. Each pass included 5 deformation passes, with a single-pass reduction rate controlled at 5%, a cumulative reduction rate controlled at 25%, and a final rolling temperature of not less than 860°C per pass.

[0161] Comparative Example 7

[0162] Compared with Example 2, in Comparative Example 7's "S5 multi-pass rolling", all 5 passes adopt a unidirectional rolling method, and the specific implementation method is as follows:

[0163] S5: Multi-pass rolling;

[0164] The titanium alloy sheet obtained in S4 was heated to 80°C below the β phase transformation point and held for 3 hours. The sheet thickness was then controlled using a multi-pass rolling process to obtain the titanium alloy sheet. The multi-pass rolling was controlled to be 5 passes. After each pass, the sheet was returned to the furnace to be heated to 80°C below the β phase transformation point and held for 1 hour before continuing rolling. Unidirectional rolling was preferred during the rolling process. Each pass included 5 deformation passes, with a single-pass reduction rate controlled at 10% and a cumulative reduction rate controlled at 20%. The final rolling temperature for each pass was not lower than 860°C.

[0165] Comparative Example 8

[0166] Compared with Example 1, in the "S6 heat treatment" of Comparative Example 8, the solution temperature is less than 50°C below the phase transition point. The specific implementation method is as follows:

[0167] S6: Heat treatment;

[0168] The titanium alloy sheet obtained in S5 was heated to 20°C below the β phase transformation point, held for 2 hours, and then subjected to solution treatment, followed by air cooling to room temperature. The sheet was then heated to 600°C, held for 2 hours, and then subjected to aging treatment, followed by air cooling to room temperature, ultimately yielding a titanium alloy sheet with excellent impact resistance. After the solution and aging treatments, the sheet underwent surface treatment and oxide scale removal.

[0169] Technical effects:

[0170] The mechanical properties of the titanium alloy plates obtained in Examples 1-4 and Comparative Examples 1-8 in the RD-ND and TD-ND directions were tested according to "GB / T 228.1-2021 Metallic materials, tensile testing, Part 1: Test method at room temperature" and "GB / T229-2020 Metallic materials, Charpy pendulum impact test method". The results are shown in Table 1.

[0171] Table 1. Mechanical properties of titanium alloy sheets obtained in the ND direction of Examples 1-4 and Comparative Examples 1-8

[0172]

[0173] The mechanical properties of the titanium alloy plates obtained in Examples 1-4 and Comparative Examples 1-8 in the RD and TD directions were tested according to "GB / T 228.1-2021 Metallic materials, tensile testing—Part 1: Test methods at room temperature". The results are shown in Table 2.

[0174] Table 2 Mechanical properties of titanium alloy sheets obtained in the RD and TD directions of Examples 1-4 and Comparative Examples 1-8

[0175]

[0176] Mechanical property data reveals that:

[0177] Data from Examples 1-4 show that the titanium alloy plates prepared by the proposed method exhibit excellent resistance to crack initiation and propagation when subjected to impact loads from the ND direction. They possess good strength in the ND direction and excellent plasticity in the RD and TD directions, with other corresponding mechanical properties meeting industry application standards. In contrast, in Comparative Example 1, the forging blank lacks the aforementioned characteristics, exhibiting good isotropy and ensuring high strength, but its impact resistance is significantly lower. In Comparative Example 2, for the forging blank with the aforementioned characteristics, a pretreatment scheme with relatively high temperature and large deformation is used, further increasing the initial β grains in the material and enhancing the microstructure genetic characteristics. Simultaneously, the increased deformation makes the anisotropy more pronounced, resulting in excellent tensile properties in the ND direction, but a significant decrease in mechanical properties in the RD and TD directions, and its impact resistance is not objective. In Comparative Example 3, for the forging blank without the aforementioned characteristics, a pretreatment scheme with relatively low temperature and small deformation is used, resulting in insignificant microstructure genetic characteristics in the material, which are not enhanced, thus exhibiting superior isotropy. In Comparative Example 4, the increased deformation during the pressing and shaping process disrupted the original microstructure and macro-region characteristics, resulting in refined grains, uniform grain orientation, and predominant isotropy. In Comparative Example 5, instead of widening along the TD direction, widening was performed alternately along the TD and RD directions, which strengthened the orientation characteristics in the RD direction during subsequent processes, resulting in enhanced plasticity in the RD direction. This is detrimental to the plate being subjected to impact loads in the ND direction. Similarly, in Comparative Example 6, the cross-rolling method enhanced the orientation in the TD direction, and in Comparative Example 7, the unidirectional rolling method enhanced the orientation in the RD direction. Both of these are detrimental to the plate being subjected to impact loads in the ND direction. In Comparative Example 8, the excessively high solution temperature caused recrystallization within the material, weakening anisotropy and improving the material's isotropy.

[0178] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for improving the impact resistance and explosion resistance of titanium alloys, characterized in that, By controlling the macro-region structure and texture distribution of the titanium alloy sheet, a slender strip-shaped macro-region structure is formed on the cross section parallel to the impact direction. Its IPF diagram shows obvious slender strip-shaped orientation macro-region characteristics, and the {0001} basal plane poles are uniformly distributed in the plane perpendicular to the impact direction, while the {10-10} and {11-20} crystal plane poles are uniformly distributed relative to the sample coordinate system.

2. The method for improving the impact resistance and explosion resistance of titanium alloys according to claim 1, characterized in that, The titanium alloy sheet comprises, by weight percentage: Al: 5.5 ~ 6.5%, Mo + Nb: 3.5 ~ 4.5%, of which Nb ≤ 3.5%, Zr + Sn: 1.5 ~ 3.0%, with the balance being Ti and unavoidable impurities.

3. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 1 or 2, characterized in that, When a titanium alloy forging billet with a specified microstructure is used as the original billet, the preparation process sequentially includes S1-1, S2-1, S3, S4, S5 and S6. When a titanium alloy forging billet with a specified microstructure is not used as the original billet, the preparation process sequentially includes S1-2, S2-2, S3, S4, S5 and S6. The specific steps are as follows: S1: Forging selection; Titanium alloy forging billets were selected as the raw materials; S1-1: Select crystals with elongated macro-region characteristics. <0001> Titanium alloy forging blanks with uniformly distributed orientation within the RD-TD plane and retaining the genetic characteristics of the microstructure; S1-2: Select crystals that do not have elongated macro-region characteristics. <0001> Titanium alloy forging blanks with uniform orientation distribution within the forging and weak microstructure inheritance characteristics; S2: Heating and pretreatment of forgings; The original billet is subjected to high-temperature heating, heat preservation, and shaping treatment; S2-1: Heat the forging billet obtained from S1-1 to 60-80℃ above the β phase transformation point, hold for 20-30 minutes, and perform high-temperature shaping; S2-2: Heat the forging billet obtained from S1-2 to 100-120°C above the β phase transformation point, hold for 2-3 hours, and perform high-temperature shaping; S3: Square shaping; The forging billet treated with S2-1 or S2-2 is squared to obtain a titanium alloy square block. S4: Widening and shaping; The square block obtained in step S3 is laterally stretched and deformed to obtain a stretched titanium alloy plate. S5: Multi-pass rolling; The widened plate obtained in step S4 is subjected to multiple hot rolling processes to obtain titanium alloy sheet. S6: Heat treatment; The titanium alloy sheet obtained in step S5 is subjected to solution treatment and aging treatment in sequence to obtain the titanium alloy sheet with excellent impact resistance and explosion resistance.

4. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, In step S1-1, the volume of the forging billet is 115% to 135% of the volume of the desired finished sheet metal; in step S1-2, the volume of the forging billet is 120% to 140% of the volume of the desired finished sheet metal. Before the forging enters the subsequent heating and shaping process, the surface of the forging is cleaned to remove surface oxide scale, oil stains, folds, cracks and indentation defects. The thickness removed on one side is 2 to 4 mm.

5. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, When using a forging billet with a specified microstructure, in step S2-1, the titanium alloy forging billet obtained in step S1-1 is heated to 60-80°C above the β phase transformation point, held for 20-30 minutes, and then transferred to a forging press for high-temperature shaping. The heating method is furnace heating, with a heating rate of 5 ~ 10℃ / min; before forming the forging, the corners are chamfered or rounded, with a chamfer radius or rounded radius of 10 ~ 25mm; the single-pass reduction of the high-temperature forming process is 5% ~ 8%, the total deformation of a single heat treatment is 10% ~ 20%, and the final forging temperature is not lower than the β phase transformation point temperature; When a forging billet with a specified microstructure is not used, in step S2-2, the titanium alloy forging billet obtained in step S1-2 is heated to 100-120°C above the β phase transformation point, held for 2-3 hours, and then transferred to a forging press for high-temperature shaping. The heating method is furnace heating, with a heating rate of 5 ~ 10℃ / min; before forming the forging, the corners are chamfered or rounded, with a chamfer radius or rounded radius of 10 ~ 25mm; the single-pass reduction of the high-temperature forming process is 15% ~ 18%, the total deformation of a single heat treatment is 30% ~ 36%, and the final forging temperature is not lower than 20℃ above the β phase transformation point.

6. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, In step S3, the forging billet treated by S2-1 or S2-2 is heated to 20-60°C below the β phase transformation point and held for 2-3 hours, and then squared. The squared shape includes first lightly pressing along any side of the forging billet to make the upper and lower surfaces flat, and then pressing along the perimeter of the forging billet multiple times, so that the forging billet gradually forms a square or rectangular billet when viewed from the ND direction. The reduction amount of each pass is 5%-10%, the total deformation amount is 10%-20%, and the final forging temperature is not lower than 850°C.

7. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, In step S4, the titanium alloy square block obtained in step S3 is heated to 10-40°C below the β phase transformation point and held for 2-3 hours. It is then widened and deformed using a multi-pass transverse pressing method. Before widening, 1-2 passes of pre-pressing are performed, with a single-pass reduction rate of 3%-8%. Widening is carried out along the TD direction, with the pressing direction being the ND direction. The single-pass reduction rate is 8%-15%, and the total deformation is 30%-32%. The single-pass feed is 200-300mm, and the feed rate is 3-8 seconds per pass. The end temperature of a single pass is not lower than 850°C. If the temperature is lower than this, the block needs to be returned to the furnace and heated to 10-40°C below the β phase transformation point before continuing widening.

8. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, In step S5, the widened plate obtained in step S4 is heated to 40-80°C below the β phase transformation point and held for 2-3 hours, and then rolled in 2-5 passes. After each pass, the plate is returned to the furnace to be heated to 40-80°C below the β phase transformation point and held for 0.5-1 hours before continuing rolling. Each pass includes 2-5 passes, with a single pass reduction rate of 5%-10% and a single pass cumulative reduction rate of 20%-25%. The final rolling temperature of each pass is not lower than 860°C. The first 3 passes are rolled in one direction, and when there are more than 3 passes, cross rolling is used.

9. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, In step S6, the rolled titanium alloy sheet obtained in step S5 is heated to 50-80°C below the β phase transformation point and held for 2-4 hours for solution treatment, followed by air cooling to room temperature; then heated to 600-700°C and held for 2-4 hours for aging treatment, followed by air cooling to room temperature; the Ti-6Al-4Mo-1Zr-1Sn titanium alloy sheet undergoes surface treatment and oxide scale removal after solution aging treatment.

10. The preparation process of the method for improving the impact resistance and explosion resistance of titanium alloys according to claim 3, characterized in that, The titanium alloy sheet obtained by this preparation process is used to manufacture load-bearing skins, fuselage bulkheads, compartment panels, reinforcing ribs, webs, connecting plates, thermal insulation load-bearing plates, or locally damaged structural plates. The titanium alloy sheet is suitable for thin-walled or medium-thick-walled structural components that can withstand in-plane tensile loads, bending loads, fatigue loads, local impact loads, explosive impact loads, or complex alternating loads. Furthermore, the titanium alloy sheet has improved impact load resistance and explosive impact load resistance along the ND direction.

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