Method for preparing α-titanium alloy sheet having high deformation twin density

Abstract

The present invention relates to the technical field of titanium alloys, and discloses a method for preparing an α-titanium alloy sheet having a high deformation twin density. The method comprises: adding sponge titanium, aluminum shot, titanium diboride, Ti-32Fe and titanium dioxide, which act as raw materials, into a smelting furnace, and performing three instances of vacuum arc remelting to obtain an ingot; measuring the phase transition point Tβ of a Ti-Al-B-based alloy by means of a differential thermal analysis method, and performing two-heat hot rolling on the ingot to obtain a slab; and heating the slab to a temperature of Tβ, maintaining the temperature for the first time, then cooling same with water, reheating the slab to a temperature of (Tβ-200)°C, maintaining the temperature for the second time, and then air-cooling same to room temperature, so as to obtain a sheet. In the present invention, a sheet having a high deformation twin density is prepared by, with respect to a Ti-Al-B-based α-titanium alloy, using a design involving increasing the β-stabilizing element Fe and microalloying the element, performing three instances of vacuum arc remelting, and using a three-heat hot rolling process involving direct-rolling cogging and a high deformation per pass. The structural uniformity and the strength-toughness balance of the alloy are ensured at low costs.

Description

A method for preparing α-titanium alloy plates with high deformation twin density

[0001] This application claims priority to Chinese Patent Application No. 202411076750.7, filed on August 7, 2024, entitled "A Method for Preparing a High Deformation Twin Density α-Titanium Alloy Sheet", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of titanium alloy technology, and in particular to a method for preparing a high deformation twin density α-titanium alloy sheet. Background Technology

[0003] Ti-Al-B α-titanium alloys, with their excellent corrosion resistance, moderate strength, good ductility and toughness, and excellent weldability, are ideal structural materials for marine environments and have been widely used in various mechanical components in the shipbuilding industry. Generally, with the increase of impurity elements such as Fe and O, the strength and hardness of titanium alloys increase, while their ductility and toughness decrease significantly. Different impurity elements have significantly different effects on the strength, ductility, and toughness of Ti-Al-B α-titanium alloys. Therefore, by reasonably controlling the content of impurity elements in the alloy, the overall mechanical properties of the alloy can be improved.

[0004] CN115747690A discloses a method for preparing a close-packed hexagonal metallic material containing ultra-high-density twins. The metallic material prepared by this method has ultra-high-density twins and a significant strengthening and toughening effect. However, this invention only applies to pure metal blocks, which are small in size and are limited to laboratory-scale trials, thus having limitations in practical applications. CN115537695A discloses a method for preparing a TB8 titanium alloy with a nanotwinned structure. This method uses high-voltage pulse treatment to induce a nanotwinned structure in the TB8 titanium alloy, resulting in a good balance between tensile strength and plasticity. This gives the metastable β-type TB8 titanium alloy excellent comprehensive material properties. However, this invention focuses on the preparation method of β-titanium alloy twins and does not address the preparation method of α-titanium alloy twins.

[0005] Therefore, there is a need to improve the preparation method of high deformation twin density α-titanium alloy plates in the existing technology. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose a method for preparing high deformation twin density α-titanium alloy plates. For Ti-Al-B system α-titanium alloys, a microalloying design with the addition of the β-stabilizing element Fe is adopted. Through three vacuum consumable melting processes, and by using a direct rolling billet opening + high-pass deformation two-fire hot rolling process, a high-density deformation twin plate is prepared. This method ensures the uniformity of the alloy's microstructure and the matching of its strength and toughness at a relatively low cost.

[0007] To achieve the above objectives, this invention provides a method for preparing a high deformation twin density α-titanium alloy sheet, comprising the following steps:

[0008] S1 Smelting: Sponge titanium, aluminum briquettes, titanium diboride, Ti-32Fe, and titanium dioxide are added to the smelting furnace and subjected to three vacuum consumable melting processes to obtain ingots.

[0009] S2 hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β The ingot is hot-rolled twice to obtain a slab;

[0010] S3 solution aging heat treatment: heating the slab to T β The temperature is first maintained at a certain level, then water-cooled, and then the slab is heated to (T). β After a second insulation at -200℃, the material is air-cooled to room temperature to obtain the board.

[0011] In this process, the first rolling is a direct rolling process with a heating temperature of T. β +100℃, holding time is 100-120 min, rolling passes are 2-3, deformation in the first pass is ≥50%, and deformation in the remaining passes is ≥30%, rolling into a slab with a thickness of 40-55 mm; the heating temperature for the second rolling is T. β The temperature is ±10℃, the holding time is 80~100min, the rolling passes are 5~6, the deformation per pass is ≥18%, the total deformation of the two rolling passes is ≥70%, and the slab is rolled into a thickness of 5~15mm.

[0012] In some implementations, in S1, the amount of element added, by mass percentage, includes:

[0013] 3.3% ≤ [Al]% ≤ 4.8%, 0.2% ≤ [Fe]% ≤ 0.4%, 0.005% ≤ [B]% ≤ 0.007%, with the balance being titanium and unavoidable impurities.

[0014] In some embodiments, the sponge titanium is 0A grade sponge titanium, with impurity element content of [C]% ≤ 0.01%, [N]% ≤ 0.01%, [O]% ≤ 0.04%, [H]% ≤ 0.001%, and [Fe]% ≤ 0.02%.

[0015] In some embodiments, the impurity element contents in Ti-32Fe are [C]% ≤ 0.2%, [N]% ≤ 0.1%, [O]% ≤ 0.2%, and [Si]% ≤ 0.1%.

[0016] In some embodiments, in S1, the purity of the aluminum bean is ≥99.7%, the purity of Ti-32Fe is ≥99.8%, and the purity of the titanium dioxide is ≥99.5%.

[0017] In some embodiments, in S2, the vacuum degree in the vacuum self-consuming furnace during the melting process is ≤3.0Pa, the arc stabilizing current is 5-12A, the melting voltage during the melting stage is 20-40V, and the melting current is 3-10kA.

[0018] In some implementations, in step S2, the ingot is peeled, flattened, and surface-machined.

[0019] In some implementations, in S3, the first heat preservation time is 100-120 minutes, and the second heat preservation time is 80-100 minutes.

[0020] In some embodiments, in S3, the heating rate of the solution aging heat treatment is 20°C / s.

[0021] In some embodiments, in S3, the target grain size of the α grains grown during the aging process is 20–40 μm.

[0022] The present invention has at least the following beneficial technical effects:

[0023] This invention addresses the problem of poor strength and toughness matching in Ti-Al-B titanium alloys. It employs a microalloying design with added β-stabilizing element Fe to improve the strength-toughness balance. A three-stage vacuum arc remelting method ensures the uniformity of titanium alloy ingot composition. Direct rolling followed by two high-pass deformation two-stage hot rolling yields plates with a thickness of 5–15 mm, further promoting the formation of deformation twins. The addition of Fe alters the stacking fault energy of the alloy, leading to the formation of growth twins (twin formation is closely related to stacking fault energy, and growth twins are uncommon in titanium alloys; twins in titanium alloys are generally deformation twins, which improve the mechanical properties of the alloy). The high-pass deformation hot rolling further promotes the formation of deformation twins. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a flowchart of the preparation method of high deformation twin density α titanium alloy plate according to an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of the microstructure embodiment of Embodiment 1 provided by the present invention;

[0027] Figure 3 is a schematic diagram of the microstructure embodiment of Embodiment 2 provided by the present invention;

[0028] Figure 4 is a schematic diagram of the microstructure embodiment of Embodiment 3 provided by the present invention;

[0029] Figure 5 is a schematic diagram of the microstructure embodiment of Comparative Example 1 provided by the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0031] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0032] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] This invention targets Ti-Al-B α-titanium alloys, employing a microalloying design with the addition of the β-stabilizing element Fe. Through three vacuum arc remelting processes and a two-pass hot rolling process with high deformation, high-density deformed twinned plates are prepared. This approach ensures the uniformity of the alloy's microstructure and a good balance of strength and toughness at a relatively low cost. As shown in Figure 1, the specific method includes the following steps:

[0034] S1 Smelting: Sponge titanium, aluminum briquettes, titanium diboride, Ti-32Fe, and titanium dioxide are added to the smelting furnace and subjected to three vacuum consumable melting processes to obtain ingots.

[0035] S2 hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β The ingot is hot-rolled twice to obtain a slab;

[0036] S3 solution aging heat treatment: heating the slab to T β The temperature is first maintained at a certain level, then water-cooled, and then the slab is heated to (T). β After a second insulation at -200℃, the material is air-cooled to room temperature to obtain the board.

[0037] In this process, the first rolling is a direct rolling process with a heating temperature of T. β +100℃, holding time is 100-120 min, rolling passes are 2-3, deformation in the first pass is ≥50%, and deformation in the remaining passes is ≥30%, rolling into a slab with a thickness of 40-55 mm; the heating temperature for the second rolling is T. β The temperature is ±10℃, the holding time is 80~100min, the rolling passes are 5~6, the deformation per pass is ≥18%, the total deformation of the two rolling passes is ≥70%, and the slab is rolled into a thickness of 5~15mm.

[0038] Furthermore, in S1, 0A-grade sponge titanium, aluminum briquettes (purity ≥99.7%), titanium diboride, Ti-32Fe (purity ≥99.8%), and titanium dioxide (≥99.5%) are used as raw materials. To address the poor strength-toughness matching of Ti-Al-B titanium alloys, the method of increasing the β-stabilizing element Fe is employed to reduce the stacking fault energy of the alloy, thereby leading to the formation of growth twins. The twin boundaries hinder crack propagation, thus improving the strength and toughness of the alloy and achieving the goal of harmonizing the strength and toughness of the alloy. 0A-grade sponge titanium is selected with impurity element content of [C]% ≤0.01%, [N]% ≤0.01%, [O]% ≤0.04%, [H]% ≤0.001%, and [Fe]% ≤0.02%; Ti-32Fe is selected with impurity element content of [C]% ≤0.2%, [N]% ≤0.1%, [O]% ≤0.2%, and [Si]% ≤0.1%. .

[0039] Furthermore, in S1, the element additions, by mass percentage, are: 3.3% ≤ [Al]% ≤ 4.8%, 0.2% ≤ [Fe]% ≤ 0.4%, 0.005% ≤ [B]% ≤ 0.007%, with the balance being titanium and unavoidable impurities. The raw materials are subjected to three vacuum arc remelting processes according to this ratio. During the remelting process, the vacuum degree in the vacuum arc remelting furnace is ≤ 3.0 Pa, the arc stabilizing current is 5–12 A, the remelting voltage is 20–40 V, and the remelting current is 3–10 kA to obtain ingots with a diameter of Ф250 mm * 300 mm. These ingots are then peeled and leveled to remove surface oxides and impurities, and after surface finishing, they undergo heat treatment. The vacuum arc remelting method is employed, which has excellent non-metallic impurity removal capabilities, ensuring the purity and compositional uniformity of the titanium alloy ingots.

[0040] Furthermore, in S2, the phase transformation point T of the Ti-Al-B alloy was determined using differential thermal analysis. β The ingots are processed into square billets of 120-170mm*200mm*300mm, which are then rolled twice to produce slabs of 5-15mm thickness. A two-roll hot rolling mill is used, and the single-pass rolling adopts direct rolling for billet opening, eliminating the forging process and thus saving processing costs. The single-pass rolling adopts a large deformation amount, which on the one hand can refine the grains and improve the strength of the plate; on the other hand, the high deformation amount can provide more stored energy, which can promote the formation of deformation twins, thereby improving the strength and toughness matching of the alloy.

[0041] Furthermore, in S3, solution aging: the hot-rolled slab is heated to T β Hold the temperature at 60–90 minutes, then water cool, and then heat the slab to (T). β After holding at -200℃ for 2–4 hours, air-cool to room temperature. In some embodiments, the heat treatment heating rate is 20℃ / s, with the temperature rising with the furnace. A solution aging heat treatment process is adopted, which ensures that the β phase is completely retained at room temperature during the solution treatment process. Due to rapid cooling, the grains do not have time to grow, thus obtaining uniform and fine grains. The aging process causes the β phase after solution treatment to slowly decompose and precipitate, which plays a role in dispersion strengthening and improves the strength of the alloy. In addition, the primary α grains slowly grow to the target grain size of 20–40 μm during the aging process. This grain size is moderate, which can improve the strength and plasticity of the grains, better prevent crack propagation, and increase the impact toughness of the alloy.

[0042] The present invention will be further explained and described below with reference to specific embodiments.

[0043] Example 1

[0044] ① Composition design: Fe element micro-alloying is adopted to improve the strength and toughness matching of Ti-Al-B system titanium alloy. The element addition amount (mass percentage) is: [Al]% = 4.3%, [Fe]% = 0.25%, [B]% = 0.005%, and the balance is titanium element and unavoidable impurities.

[0045] ② Vacuum self-consuming furnace smelting: Using 0A grade sponge titanium, aluminum briquettes (purity ≥99.7%), titanium diboride, Ti-32Fe (purity ≥99.8%), and titanium dioxide (≥99.5%) as raw materials, the raw materials are proportioned according to the mass percentage in step ①, and three vacuum self-consuming furnace smelting processes are carried out. During the smelting process, the vacuum degree in the vacuum self-consuming furnace is ≤3.0Pa. The arc stabilization currents for the three vacuum smelting processes are 6A, 9A, and 11A, respectively. The smelting voltages for the three smelting stages are 28V, 32V, and 35V, and the vacuum smelting currents for the three smelting processes are 5kA, 8kA, and 10kA, respectively. Ingots with a diameter of Ф250*300mm are obtained. The ingots are peeled and flattened to remove surface oxides and impurities. After surface polishing, they are subjected to heat treatment.

[0046] ③ Hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β =994.8℃, the ingot obtained in step ② is processed into a square billet of 170mm*200mm*300mm. The first rolling (direct rolling) heating temperature is 1094.8℃, the holding time is 100min, the rolling passes are 3, the deformation of the first pass is 50%, and the deformation of the remaining passes are 30.6% and 32.3% respectively, the total deformation of the first rolling is 76.5%, the final rolling temperature is 820℃, and the rolled billet is 40mm thick; the second rolling heating temperature is 994.8℃, the holding time is 80min, the rolling passes are 6, the deformation of the 6 passes are 18%, 19.2%, 18.1%, 19.35%, 19.4%, and 18.4% respectively, the total deformation of the second rolling is 71.25%, the final rolling temperature is 832℃, and the rolled billet is 11.5mm thick.

[0047] ④ Solution aging treatment: Heat the hot-rolled sheet to 994.8℃ and hold for 60 minutes, then cool with water. Then heat the sheet to 794.8℃ and hold for 4 hours, then air cool to room temperature.

[0048] Example 2

[0049] ① Composition design: Fe element micro-alloying is adopted to improve the strength and toughness matching of Ti-Al-B system titanium alloy. The element addition amount (mass percentage) is: [Al]% = 4.3%, [Fe]% = 0.25%, [B]% = 0.005%, and the balance is titanium element and unavoidable impurities.

[0050] ② Vacuum self-consuming furnace smelting: Using 0A grade sponge titanium, aluminum briquettes (purity ≥99.7%), titanium diboride, Ti-32Fe (purity ≥99.8%), and titanium dioxide (≥99.5%) as raw materials, the raw materials are proportioned according to the mass percentage in step ①, and three vacuum self-consuming furnace smelting processes are carried out. During the smelting process, the vacuum degree in the vacuum self-consuming furnace is ≤3.0Pa. The arc stabilization currents for the three vacuum smelting processes are 6A, 9A, and 11A, respectively. The smelting voltages for the three smelting stages are 28V, 32V, and 35V, and the vacuum smelting currents for the three smelting processes are 5kA, 8kA, and 10kA, respectively. Ingots with a diameter of Ф250*300mm are obtained. The ingots are peeled and flattened to remove surface oxides and impurities. After surface polishing, they are subjected to heat treatment.

[0051] ③ Hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β =994.8℃, the ingot obtained in step ② is processed into a square billet of 150mm*200mm*300mm. The first rolling (direct rolling) heating temperature is 1094.8℃, the holding time is 100min, the rolling passes are 2, the deformation of the first pass is 50%, the deformation of the remaining passes is 40%, the total deformation of the first rolling is 70%, the final rolling temperature is 803℃, and the billet is rolled into a 45mm thick slab; the second rolling heating temperature is 994.8℃, the holding time is 80min, the rolling passes are 6, the deformation of the 6 passes are 20%, 19.4%, 20.7%, 21.7%, 19.4%, and 20.7% respectively, the total deformation of the second rolling is 74.4%, the final rolling temperature is 812℃, and the billet is rolled into an 11.5mm thick slab.

[0052] ④ Solution aging treatment: Heat the hot-rolled sheet to 993.1℃ and hold for 60 minutes, then cool with water. Then heat the sheet to 794.8℃ and hold for 4 hours, then air cool to room temperature.

[0053] Example 3

[0054] ① Composition design: Fe element micro-alloying is adopted to improve the strength and toughness matching of Ti-Al-B system titanium alloy. The element addition amount (mass percentage) is: [Al]% = 4.3%, [Fe]% = 0.35%, [B]% = 0.005%, and the balance is titanium element and unavoidable impurities.

[0055] ② Vacuum self-consuming furnace smelting: Using 0A grade sponge titanium, aluminum briquettes (purity ≥99.7%), titanium diboride, Ti-32Fe (purity ≥99.8%), and titanium dioxide (≥99.5%) as raw materials, the raw materials are proportioned according to the mass percentage in step ①, and three vacuum self-consuming furnace smelting processes are carried out. During the smelting process, the vacuum degree in the vacuum self-consuming furnace is ≤3.0Pa. The arc stabilization currents for the three vacuum smelting processes are 6A, 9A, and 11A, respectively. The smelting voltages for the three smelting stages are 28V, 32V, and 35V, and the vacuum smelting currents for the three smelting processes are 5kA, 8kA, and 10kA, respectively. Ingots with a diameter of Ф250*300mm are obtained. The ingots are peeled and flattened to remove surface oxides and impurities. After surface polishing, they are subjected to heat treatment.

[0056] ③ Hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β =993.1℃, the ingot obtained in step ② is processed into a square billet of 150mm*200mm*300mm. The first rolling (direct rolling) heating temperature is 1093.1℃, the holding time is 100min, the rolling passes are 2, the deformation of the first pass is 50%, the deformation of the remaining passes is 40%, the total deformation of the first rolling is 70%, the final rolling temperature is 803℃, and the billet is rolled into a 45mm thick slab; the second rolling heating temperature is 993.1℃, the holding time is 80min, the rolling passes are 6, the deformation of the 6 passes are 20%, 19.4%, 20.7%, 21.7%, 19.4%, and 20.7% respectively, the total deformation of the second rolling is 74.4%, the final rolling temperature is 812℃, and the billet is rolled into an 11.5mm thick slab.

[0057] ④ Solution aging treatment: Heat the hot-rolled sheet to 993.1℃ and hold for 60 minutes, then cool with water. Then heat the sheet to 793.1℃ and hold for 3 hours, then air cool to room temperature.

[0058] Comparative Example 1

[0059] ① Composition design: Fe element micro-alloying is adopted to improve the strength and toughness matching of Ti-Al-B system titanium alloy. The element addition amount (mass percentage) is: [Al]% = 4.3%, [Fe]% = 0.05%, [B]% = 0.005%, and the balance is titanium element and unavoidable impurities.

[0060] ② Vacuum self-consuming furnace smelting: Using 0A grade sponge titanium, aluminum briquettes (purity ≥99.7%), titanium diboride, Ti-32Fe (purity ≥99.8%), and titanium dioxide (≥99.5%) as raw materials, the raw materials are proportioned according to the mass percentage in step ①, and three vacuum self-consuming furnace smelting processes are carried out. During the smelting process, the vacuum degree in the vacuum self-consuming furnace is ≤3.0Pa. The arc stabilization currents for the three vacuum smelting processes are 6A, 9A, and 11A, respectively. The smelting voltages for the three smelting stages are 28V, 32V, and 35V, and the vacuum smelting currents for the three smelting processes are 5kA, 8kA, and 10kA, respectively. Ingots with a diameter of Ф250*300mm are obtained. The ingots are peeled and flattened to remove surface oxides and impurities. After surface polishing, they are subjected to heat treatment.

[0061] ③ Hot rolling: The phase transformation point T of the Ti-Al-B alloy was determined by differential thermal analysis. β =998.1℃, the ingot obtained in step ② is processed into a square billet of 150mm*200mm*300mm. The first rolling (direct rolling) heating temperature is 1098.1℃, the holding time is 100min, the rolling passes are 3, the deformation of the first pass is 30%, the deformation of the remaining passes is 30% and 25.2% respectively, the total deformation of the first rolling is 63.2%, the final rolling temperature is 803℃, and the rolled billet is 55mm thick; the second rolling heating temperature is 998.1℃, the holding time is 80min, the rolling passes are 7, the deformation of the 7 passes are 20%, 20%, 19.9%, 19.9%, 19.9%, 19.9%, 20.7% respectively, the total deformation of the second rolling is 79%, the final rolling temperature is 812℃, and the rolled billet is 11.5mm thick.

[0062] ④ Solution aging treatment: Heat the hot-rolled sheet to 998.1℃ and hold for 60 minutes, then cool with water. Then heat the sheet to 798.1℃ and hold for 3 hours, then air cool to room temperature.

[0063] Tensile and impact properties of the solution-treated and aged Ti-Al-B titanium alloy sheets from Examples 1, 2, and the comparative examples were tested, and the microstructure was observed and analyzed, as shown in Table 1 and Figures 2-5. Figures 2-5 show that the titanium alloy sheets prepared according to Examples 1 and 2 have the same Fe content. The twin content in Example 1 is higher than that in Example 2, indicating that high-deformation single-pass rolling can promote twin formation. The sheet prepared in Example 3 has a higher twin content in its microstructure. Compared with the sheet prepared in Example 2, the two sheets have the same deformation, but the Fe content in Example 3 is higher, suggesting that higher Fe content leads to more twins. The comparative example shows almost no twin formation, likely due to its lower Fe content and insufficient deformation during single-pass rolling. Comparing the mechanical properties of the sheets in the examples and comparative examples in the table shows that the higher the twin content, the higher the strength-toughness ratio of the alloy, and the better the overall mechanical properties.

[0064] Table 1 Test data for tensile properties and impact properties, etc.

[0065] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0066] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0067] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0068] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method of producing a high-deformation twin-density α titanium alloy sheet material, characterized by, Comprise: S1 smelting: using sponge titanium, aluminum beans, titanium diboride, Ti-32Fe, titanium dioxide as raw materials into the smelting furnace, three vacuum consumable smelting to obtain ingot; S2 hot rolling: the phase transition point T of the Ti-Al-B alloy is measured by differential thermal analysis method β two fire hot rolling is performed on the ingot to obtain a slab S3 solution and aging heat treatment: heating the slab to T β temperature, first holding and then water cooling, and then heating the slab to (T β - 200) °C, second holding and then air cooling to room temperature to obtain a plate wherein the first rolling is straight rolling, the heating temperature is T β ±100℃, the holding time is 100-120 min, the rolling pass is 2-3, the first pass deformation is ≥50%, the remaining pass deformation is ≥30%, and the rolling is finished into a 40-55 mm thick slab; the second rolling is heated at a temperature of T β ±10℃, the holding time is 80-100 min, the rolling pass is 5-6, the deformation of each pass is ≥18%, the total deformation of the second rolling is ≥70%, and the rolling is finished into a 5-15 mm thick slab.

2. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S1, the element addition amount includes: 3.3%≤[Al]≤4.8%, 0.2%≤[Fe]≤0.4%, 0.005%≤[B]≤0.007%, the balance is titanium element and inevitable impurities, in mass percent.

3. The method of producing a high twin density alpha titanium alloy sheet according to claim 2, wherein The sponge titanium is 0A grade sponge titanium, the impurity element content [C]≤0.01%, [N]≤0.01%, [O]≤0.04%, [H]≤0.001%, [Fe]≤0.02%.

4. The method of producing a high twin density alpha titanium alloy sheet according to claim 2, wherein In the Ti-32Fe, the impurity element content [C]≤0.2%, [N]≤0.1%, [O]≤0.2%, [Si]≤0.1%.

5. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S1, the purity of aluminum beans is ≥99.7%, the purity of Ti-32Fe is ≥99.8%, and the purity of titanium dioxide is ≥99.5%.

6. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S1, the vacuum degree in the vacuum consumable furnace during smelting process is ≤3.0Pa, the stable arc current is 5-12A, the smelting voltage during smelting stage is 20-40V, and the smelting current is 3-10kA.

7. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S2, after two fire hot rolling, the ingot is subjected to skinning, flat head, surface finishing treatment.

8. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S3, the first holding time is 100-120min, and the second holding time is 80-100min.

9. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S3, the heating speed of solid solution and aging heat treatment is 20℃ / s.

10. The method of producing a high twin density alpha titanium alloy sheet according to claim 1, wherein In S3, the target grain size of α grain growth during aging process is 20-40μm.

Images