Titanium alloy with high impact performance in wide temperature range and preparation method thereof

Abstract

The application discloses a wide-temperature-range titanium alloy with high impact performance and a preparation method thereof. The wide-temperature-range titanium alloy comprises the following elements: Al 6.2-7.2wt%, Sn 1.5-2.5wt%, Zr 2.8-3.8wt%, Mo 3.5-4.5wt%, W 0.8-1.2wt%, Si 0.1-0.3wt%, Re 0.3-0.5wt%, O≤0.06wt%, N≤0.01wt%, H≤0.001wt%, and the balance of Ti. The preparation method comprises the following steps: a melting process combining electron beam cold hearth furnace melting and vacuum consumable melting is used to prepare a titanium alloy ingot; the prepared titanium alloy ingot is subjected to forging deformation or combined deformation of forging and rolling to obtain a titanium alloy blank; and the obtained titanium alloy blank is sequentially subjected to solid solution treatment and aging treatment, so that the wide-temperature-range titanium alloy with high impact performance is finally obtained. The application solves the technical bottlenecks that the existing low-temperature titanium alloy cannot be used at 500-600 DEG C and the high-temperature titanium alloy has low plasticity and impact performance at low temperature.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material system design and preparation technology, specifically relating to a wide-temperature-range titanium alloy with high impact performance and its preparation method. Background Technology

[0002] With the successful completion of my country's lunar sample return and Mars probe missions, deep space exploration has entered a new stage of manned and multi-type celestial body exploration (such as inner planets, exoplanets, and asteroids). Faced with extreme temperature environments, aerospace structural materials must possess both wide-temperature-range service capability and high impact resistance, which places higher demands on traditional titanium alloy materials.

[0003] Deep space exploration missions primarily explore the Moon and other celestial bodies beyond the Moon, as well as their surrounding space environment. Compared to Earth-orbiting spacecraft, deep space exploration missions will face more extreme space environment conditions, which pose a serious threat to the safe operation of the spacecraft itself and its various functional systems.

[0004] First, deep space environments present extreme temperatures and fluctuating temperature conditions. For example, the highest temperature in Venus's atmosphere can reach over 500°C, and asteroid probes are required to operate within a temperature range of -180 to 100°C. Furthermore, the operating temperature ranges for different celestial bodies in the solar system vary significantly (e.g., Mercury -183 to 427°C, Venus -45 to 500°C, Mars -132 to 28°C, etc.). If deep space probes were still manufactured using traditional low-temperature titanium alloys such as TA7 ELI, TC4 ELI, and CT20, they would be highly susceptible to performance degradation or even failure under these extreme temperature and fluctuating temperature environments (high-temperature environments).

[0005] Secondly, future deep space exploration missions, especially manned deep space exploration, will face a series of complex requirements, including the construction of deep space workstations, energy acquisition and utilization, and landing buffering. Therefore, deep space exploration missions place higher demands on the performance and functionality of aerospace materials, such as low-cost, wide-temperature-range reusability and excellent cryogenic shock resistance required for landing buffering.

[0006] Currently, China has successively carried out research and development on various cryogenic titanium alloys, such as TA7 ELI, TC4 ELI, and CT20. These alloys can be used at extremely low temperatures of -253℃ and possess good cryogenic mechanical properties (tensile strength greater than 1100MPa and elongation greater than 10% at -253℃). They also exhibit excellent formability at low temperatures, allowing them to be processed into various specifications of products, including bars, plates, tubes, and wires. They have already been preliminarily applied in the field of liquid rocket engines, mainly as key structural components such as hydrogen storage tanks and hydrogen pump impellers in hydrogen-oxygen engines. However, the upper limit of the operating temperature of these existing cryogenic titanium alloys is generally too low, making it difficult to meet the requirements of deep space exploration missions for wide temperature range (especially high-temperature end) service capability. Furthermore, their impact resistance in the cryogenic region still needs further improvement.

[0007] Therefore, there is an urgent need to develop a wide-temperature-range titanium alloy with high impact performance and its preparation method, so that it can have both excellent comprehensive mechanical properties and impact resistance under extreme temperature cycling conditions (-253 to 600℃ or wider temperature range), in order to fill the research gap in wide-temperature-range titanium alloys for next-generation deep space exploration structural materials.

[0008] Patent application CN120719175A discloses a high-strength, high-ductility α+martensitic dual-phase low-temperature titanium alloy and its preparation method, solving the problem of low-temperature ductile-brittle transition caused by the presence of the β phase in low-temperature titanium alloys. Patent application CN119640090A discloses a low-temperature titanium alloy material and its preparation method, using α-stabilizing elements (Al), β-stabilizing elements (Mo, Nb, V), and neutral elements (Zr) as the main elements, and controlling the content of interstitial elements (O), to obtain a low-temperature titanium alloy with good mechanical properties. Patent application CN119525309A discloses a method for preparing aerospace-grade TC4 ELI ultra-low temperature titanium alloy plates, significantly improving the material's strength, toughness, and room-temperature and ultra-low-temperature toughness by controlling multi-stage forging and rolling process parameters and combining them with reasonable annealing treatment.

[0009] While the aforementioned patented technologies can solve the technical problems existing in their respective fields, none of them can meet the requirements for wide-temperature-range service. Therefore, it is urgent to develop a new type of wide-temperature-range titanium alloy that can withstand alternating high and low temperatures and has high impact performance. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides a wide-temperature-range titanium alloy with high impact performance. The mass percentages of each element in the wide-temperature-range titanium alloy are as follows: Al 6.2-7.2wt%, Sn 1.5-2.5wt%, Zr 2.8-3.8wt%, Mo 3.5-4.5wt%, W 0.8-1.2wt%, Si 0.1-0.3wt%, Re 0.3-0.5wt%, O≤0.06wt%, N≤0.01wt%, H≤0.001wt%, with the balance being Ti.

[0011] Preferably, certain elements in the wide-temperature-range titanium alloy must simultaneously meet the following conditions: (1) Al + Mo + 100O ≤ 16wt%, where Al, Mo, and O represent the mass percentage of the corresponding elements; (2) The Re content is negatively correlated with the sum of W+Mo content. Within the range of the sum of Re content and W+Mo content, when the amount of Re added increases by 0.1wt%, the amount of W+Mo added decreases by 0.5-1.0wt%.

[0012] The roles of each alloying element in this invention are as follows: The high contents of Al, Mo, and Zr together provide sufficient solid solution strengthening effect, effectively compensating for the strength loss caused by the strict limitation of the contents of interstitial elements such as O and N. Among them, Al, as an α-phase stabilizer, mainly contributes high-temperature strength, Mo, as a β-phase stabilizer, mainly contributes toughness and hardenability, and Zr, as a neutral strengthening element, plays a solid solution strengthening role in both phases.

[0013] W is a β-eutectoid element, but its eutectoid reaction temperature is high and its diffusion rate is slow. Therefore, W-containing alloys have better thermal stability and high-temperature strength than alloys containing Cr and other elements.

[0014] The addition of trace amounts of Si can precipitate fine silicides at the grain boundaries, which significantly improves the high-temperature durability and creep resistance of the alloy without reducing its plasticity and toughness, thus helping to maintain its mechanical properties over a wide temperature range.

[0015] Sn, as a neutral solid solution strengthening element, has high solid solubility in both α-Ti and β-Ti. It can effectively improve the creep resistance of alloys through solid solution strengthening, and has little effect on the phase transformation temperature.

[0016] Re, as a powerful β-stabilizer and slow-diffusion element, significantly enhances the high-temperature strength and creep properties of alloys through solid solution strengthening and nano-precipitation. Simultaneously, Re refines grains and inhibits the growth of brittle phases, effectively compensating for strength losses caused by the confinement of interstitial elements and optimizing performance balance over a wide temperature range.

[0017] Condition (1): By limiting the total amount of Al, Mo and O, the alloy is prevented from becoming embrittled (to prevent the β phase from being insufficient due to excessive α stabilizing elements), and the content of interstitial element O is controlled to ensure low-temperature toughness, thus ensuring that the alloy has a good hot working window.

[0018] Condition (2): Utilizing the strong β-stabilizing and strengthening effect of Re, while reducing the total amount of traditional β-stabilizing elements (W, Mo), the strength loss that may be caused by the reduction of W and Mo can be compensated by replacing Re, thereby optimizing the alloy density while maintaining or improving the high-temperature strength and thermal stability of the alloy.

[0019] This invention also provides a method for preparing a wide-temperature-range titanium alloy with high impact resistance, the preparation method comprising the following steps in sequence: Step 1: Prepare round titanium alloy ingots using a melting process that combines electron beam cold hearth furnace melting and vacuum consumable melting. Step 2: Forge or combine forging and rolling to deform the prepared round titanium alloy ingot to obtain the titanium alloy billet of the desired shape. Step 3: The obtained titanium alloy billet is subjected to solution treatment and aging treatment in sequence to finally obtain a wide-temperature-range titanium alloy with high impact performance.

[0020] Preferably, in step one, during the smelting stage, the titanium alloy raw materials are added as follows: Sn, Zr, Mo, Si, and W are added in the form of Ti-Sn master alloy, Al-Zr master alloy, Al-Mo master alloy, Al-Si master alloy, and Al-W master alloy, respectively; the Al portion is added in the form of Al-W master alloy, and the insufficient portion is added in the form of high-purity aluminum briquettes and / or aluminum foil; Re is added in the form of elemental rhenium; the insufficient Ti portion is added in the form of sponge titanium; the diameter of the titanium alloy ingot is 350-400 mm and the length is 1-1.2 m.

[0021] In this invention, electron beam cold hearth furnace melting utilizes its high vacuum environment and the continuous renewal of the melt surface to powerfully remove gaseous elements such as H and N, while simultaneously promoting the escape of CO gas generated by the carbon-oxygen reaction, ultimately obtaining an ultra-pure titanium alloy ingot with extremely low content of interstitial elements such as O, N, and H.

[0022] In any of the above schemes, it is preferred that in step one, the smelting stage includes three smelting processes, the first smelting process is electron beam cold hearth furnace smelting, and the second and third smelting processes are both vacuum consumable melting.

[0023] In any of the above schemes, preferably, in step one, the main parameters of the first melting process include: vacuum degree 0.01-0.5Pa, melting gun power 180-240kW, molten pool temperature 1750-1850℃, and melting time 4-8h; the main parameters of the second melting process include: vacuum degree not higher than 1Pa, current 5200-5700A, and voltage 28-34V; the main parameters of the third melting process include: vacuum degree not higher than 1Pa, current 6000-7000A, and voltage 28-34V.

[0024] In any of the above schemes, preferably, in step two, the forging deformation process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and a holding time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (℃), D is the diameter of the titanium alloy ingot (mm), and K is a temperature coefficient with a set value of 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging equipment for 5-10 forging cycles, with a deformation of 30-60% per cycle. After forging, it is air-cooled to room temperature.

[0025] In any of the above schemes, the preferred embodiment is that, in step two, the forging and rolling composite deformation process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and a holding time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (℃), D is the diameter of the titanium alloy ingot or the thickness of the slab (mm), and K is a temperature coefficient with a set value of 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging and rolling equipment for 3-5 forging cycles and 2-3 rolling cycles, with a deformation of 30-60% per cycle. After forging and rolling, the ingot is air-cooled to room temperature.

[0026] In any of the above schemes, it is preferred that in step three, the solution treatment temperature is 920-970℃ and the solution treatment time is 2-4h.

[0027] In any of the above schemes, it is preferred that in step three, the aging treatment temperature is 610-630℃ and the aging treatment time is 6-8h.

[0028] This invention solves the technical bottlenecks of existing low-temperature titanium alloys that cannot operate at 500–600°C and the low plasticity and impact resistance of high-temperature titanium alloys at low temperatures. The wide-temperature-range titanium alloy prepared by this invention exhibits excellent comprehensive performance under extreme temperature cycling conditions (-253°C to 600°C), meeting the requirements of next-generation deep space exploration vehicles. The tensile strength R at 600°C is [not specified in the original text]. m ≥600MPa, yield strength R p0.2 ≥500MPa, elongation A≥10%, reduction of area Z≥20%; residual strain ≤0.2% under creep stress of 150MPa and 100h at 600℃; impact absorbed energy (KU2) ≥20J at -253℃; tensile strength R at -253℃ m ≥1550MPa, elongation A≥8%.

[0029] Compared with the prior art, the present invention provides a wide-temperature-range titanium alloy with high impact performance and its preparation method, which has the following beneficial effects: (1) The present invention adopts a melting process that combines electron beam cold hearth furnace melting and vacuum self-consuming melting, which can effectively remove interstitial elements such as O, N, and H and high-density inclusions in the alloy, and obtain ultra-pure titanium alloy ingots, thereby significantly improving the plasticity and impact toughness of the alloy in low-temperature environment, avoiding the problem of low-temperature elongation and impact toughness of traditional high-temperature titanium alloys due to the high content of interstitial elements.

[0030] (2) This invention breaks through the limitation of traditional low-temperature titanium alloys that can only be used in low-temperature environments. Through reasonable alloy composition design, the alloy has both excellent high-temperature and low-temperature performance. At a high temperature of 600℃, its high-temperature strength and creep performance can reach the level of mature titanium alloys at home and abroad (such as IMI834, TA29, TA32, etc.). At the same time, at an extremely low temperature of -253℃, the alloy can still maintain good low-temperature strength and impact performance, realizing a true wide temperature range service capability.

[0031] (3) The titanium alloy prepared by this invention has excellent comprehensive mechanical properties and impact resistance under extreme temperature cycling conditions (such as -253℃ to 600℃ or a wider range), and can be processed into various specifications of products such as bars, plates, tubes and foils to meet the application requirements of different structural parts. Through multi-purpose low-cost manufacturing, it is an ideal material for large lightweight structural parts of future deep space workstations or probes. Attached Figure Description

[0032] Figure 1 This is a microstructure diagram of a wide-temperature-range titanium alloy billet after heat treatment, prepared according to a preferred embodiment of the wide-temperature-range titanium alloy with high impact performance and its preparation method of the present invention. Detailed Implementation

[0033] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0034] Example 1: According to a preferred embodiment of the wide-temperature-range titanium alloy with high impact performance of the present invention, the mass percentage of each element in the wide-temperature-range titanium alloy is as follows: Al 6.48wt%, Sn 2.05wt%, Zr 3.26wt%, Mo 4.5wt%, W 1.2wt%, Si 0.17wt%, Re 0.3wt%, O 0.042wt%, N 0.004wt%, H < 0.001wt%, with the balance being Ti.

[0035] Some elements in the wide-temperature-range titanium alloy must simultaneously meet the following conditions: (1) Al + Mo + 100O ≤ 16wt%, where Al, Mo, and O represent the mass percentage of the corresponding elements; (2) The Re content is negatively correlated with the sum of W+Mo content. Within the range of the sum of Re content and W+Mo content, when the amount of Re added increases by 0.1wt%, the amount of W+Mo added decreases by 0.5-1.0wt%.

[0036] In this embodiment, Al+Mo+100O=6.48wt%+4.5wt%+100×0.042wt%=15.18wt%; Re is taken as the minimum addition amount of 0.3wt%, and W+Mo is taken as the maximum addition amount of 5.7wt%.

[0037] This embodiment also provides a method for preparing a wide-temperature-range titanium alloy with high impact performance. The preparation method includes the following steps in sequence: Step 1: Prepare round titanium alloy ingots using a melting process that combines electron beam cold hearth furnace melting and vacuum consumable melting. Step 2: Forge or combine forging and rolling to deform the prepared round titanium alloy ingot to obtain the titanium alloy billet of the desired shape. Step 3: The obtained titanium alloy billet is subjected to solution treatment and aging treatment in sequence to finally obtain a wide-temperature-range titanium alloy with high impact performance.

[0038] In step one, during the smelting stage, the titanium alloy raw materials are added as follows: Sn, Zr, Mo, Si, and W are added in the form of Ti-Sn master alloy, Al-Zr master alloy, Al-Mo master alloy, Al-Si master alloy, and Al-W master alloy, respectively; the Al portion is added in the form of Al-W master alloy, and the insufficient portion is added in the form of high-purity aluminum briquettes and / or aluminum foil; Re is added in the form of elemental rhenium; the insufficient Ti portion is added in the form of sponge titanium; the diameter of the titanium alloy ingot is 380 mm and the length is 1.1 m.

[0039] The smelting stage includes three smelting processes. The first smelting process is electron beam cold hearth furnace smelting, while the second and third smelting processes are both vacuum consumable smelting.

[0040] The main parameters of the first melting process include: vacuum degree 0.01Pa, melting gun power 180kW, molten pool temperature 1750℃, and melting time 4h; the main parameters of the second melting process include: vacuum degree not higher than 1Pa, current 5200A, and voltage 28V; the main parameters of the third melting process include: vacuum degree not higher than 1Pa, current 6200A, and voltage 28V.

[0041] In step two, this embodiment involves forging the titanium alloy ingot. The forging process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and held for a time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (℃), D is the diameter of the titanium alloy ingot (mm), and K is a temperature coefficient set to 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging equipment for 5-10 forging cycles, with a deformation of 30-60% per cycle. After forging, it is air-cooled to room temperature.

[0042] In this embodiment, the β phase transition temperature T = 990℃, D = 380mm, and K = 0.6mm. -1 Calculations show that the heat treatment temperature is 910-1190℃ and the holding time is 198-258min.

[0043] In this embodiment, the forging process involves alternating upsetting and drawing hot deformation. First, three forging passes are performed at temperatures 30-150°C above the β-phase transformation temperature (i.e., 1020-1140°C). Then, six forging passes are performed at temperatures 20-60°C below the β-phase transformation temperature (i.e., 930-970°C). The deformation per pass is 45%, resulting in a billet.

[0044] In step three, the solution treatment temperature is 920℃ and the solution treatment time is 2h; the aging treatment temperature is 610℃ and the aging treatment time is 6h.

[0045] Compared with the prior art, this embodiment has the following beneficial effects: (1) By adopting a melting process that combines electron beam cold hearth furnace melting and vacuum consumable melting, interstitial elements such as O, N, and H and high-density inclusions in the alloy can be effectively removed to obtain ultra-pure titanium alloy ingots. (2) It breaks through the limitation that traditional low-temperature titanium alloys can only be used in low-temperature environments. Through reasonable alloy composition design, the alloy has both excellent high-temperature performance and low-temperature performance. Under high-temperature conditions of 600℃, its high-temperature strength and creep performance can reach the level of mature titanium alloys at home and abroad. At the same time, under extremely low-temperature conditions of -253℃, the alloy can still maintain good low-temperature strength and impact performance, realizing a true wide-temperature range service capability. (3) Titanium alloys have excellent comprehensive mechanical properties and impact resistance under extreme temperature cycling conditions (such as -253℃~600℃ or wider range).

[0046] Example 2: According to another preferred embodiment of the high-impact, wide-temperature-range titanium alloy and its preparation method of the present invention, the material system, preparation method, technical principle, and beneficial effects are basically the same as those in Embodiment 1, except that: The mass percentages of each element in the wide-temperature-range titanium alloy are as follows: Al 6.81wt%, Sn 2.1wt%, Zr 3.58wt%, Mo 4.08wt%, W 1.08wt%, Si 0.22wt%, Re 0.4wt%, O 0.042wt%, N 0.004wt%, H < 0.001wt%, with the balance being Ti. Some elements in the wide-temperature-range titanium alloy must simultaneously meet the following conditions: (1) Al + Mo + 100O = 6.81wt% + 4.08wt% + 100 × 0.042wt% = 15.09wt% (less than 16wt%). (2) The Re content is negatively correlated with the sum of the W and Mo contents. Within the range of the sum of the Re and W and Mo contents, when the amount of Re added increases by 0.1 wt%, the amount of W and Mo added decreases by 0.5-1.0 wt%. In this embodiment, the Re content is 0.4 wt% (an increase of 0.1 wt% compared to Example 1), and the sum of the W and Mo contents is 5.16 wt% (a decrease of 0.54 wt% compared to Example 1).

[0047] In step one, the main parameters of the first melting process include: vacuum degree 0.25Pa, melting gun power 210kW, molten pool temperature 1800℃, and melting time 6h; the main parameters of the second melting process include: vacuum degree not higher than 1Pa, current 5500A, and voltage 31V; the main parameters of the third melting process include: vacuum degree not higher than 1Pa, current 6500A, and voltage 31V.

[0048] In step two, this embodiment involves a combined forging and rolling deformation process on the titanium alloy ingot. The combined forging and rolling deformation process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and a holding time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (in °C), D is the diameter of the titanium alloy ingot or the thickness of the slab (in mm), and K is a temperature coefficient with a set value of 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging and rolling equipment for 3-5 forging cycles and 2-3 rolling cycles, with a deformation of 30-60% per cycle. After forging and rolling, the ingot is air-cooled to room temperature.

[0049] In this embodiment, the β phase transition temperature T = 990℃, D = 380mm, and K = 0.8mm. -1 Calculations show that the heat treatment temperature is 910-1190℃ and the holding time is 274-334 min.

[0050] In this embodiment, the forging process involves alternating upsetting and drawing hot deformation. First, three forging passes are performed at temperatures 30-150°C above the β-phase transformation temperature (i.e., 1020-1140°C). Then, one forging pass is performed at temperatures 20-60°C below the β-phase transformation temperature (i.e., 930-970°C). Finally, two rolling passes are performed at temperatures 20-60°C below the β-phase transformation temperature (i.e., 930-970°C). The deformation per pass is 50%, resulting in a slab.

[0051] In step three, the solution treatment temperature is 945℃ and the solution treatment time is 3 hours; the aging treatment temperature is 620℃ and the aging treatment time is 7 hours.

[0052] Example 3: According to another preferred embodiment of the wide-temperature-range titanium alloy with high impact performance and its preparation method of the present invention, the material system, preparation method, technical principle and beneficial effects are basically the same as those of Embodiment 2, except that: The mass percentages of each element in the wide-temperature-range titanium alloy are as follows: Al 7.2wt%, Sn 2.5wt%, Zr 3.8wt%, Mo 3.76wt%, W 0.8wt%, Si 0.3wt%, Re 0.5wt%, O 0.038wt%, N 0.003wt%, H < 0.001wt%, with the balance being Ti. Some elements in the wide-temperature-range titanium alloy must simultaneously meet the following conditions: (1) Al + Mo + 100O = 7.2wt% + 3.76wt% + 100 × 0.038wt% = 14.76wt% (less than 16wt%). (2) The Re content is negatively correlated with the sum of the W and Mo contents. Within the range of the sum of the Re and W and Mo contents, when the amount of Re added increases by 0.1 wt%, the amount of W and Mo added decreases by 0.5-1.0 wt%. In this embodiment, the Re content is 0.6 wt% (an increase of 0.1 wt% compared to Example 2), and the sum of the W and Mo contents is 4.56 wt% (a decrease of 0.6 wt% compared to Example 2).

[0053] In step one, the main parameters of the first melting process include: vacuum degree 0.5 Pa, melting gun power 240 kW, molten pool temperature 1850 ℃, and melting time 8 h; the main parameters of the second melting process include: vacuum degree not higher than 1 Pa, current 5700 A, and voltage 34 V; the main parameters of the third melting process include: vacuum degree not higher than 1 Pa, current 6800 A, and voltage 34 V.

[0054] In step two, this embodiment involves a combined forging and rolling deformation process on the titanium alloy ingot. The β-phase transformation temperature is T=1000℃, D=380mm, and K=0.8mm. -1 Calculations show that the heat treatment temperature is 920-1200℃ and the holding time is 274-334 min.

[0055] First, forging is performed twice at a temperature 30-150℃ above the β-phase transformation temperature (i.e., 1030-1150℃). Then, forging is performed once at a temperature 20-60℃ below the β-phase transformation temperature (i.e., 940-980℃). Finally, rolling is performed three times at a temperature 20-60℃ below the β-phase transformation temperature (i.e., 940-980℃). The deformation per forging is 50%, resulting in a slab.

[0056] In step three, the solution treatment temperature is 970℃ and the solution treatment time is 4 hours; the aging treatment temperature is 630℃ and the aging treatment time is 8 hours.

[0057] Comparative Example 1: The mass percentages of each element in the titanium alloy of this comparative example are as follows: Al 6.78wt%, Sn 2.08wt%, Zr 3.62wt%, Mo 4.1wt%, W 0.98wt%, Si 0.23wt%, Re 0.12wt%, O 0.13wt%, N 0.01wt%, H 0.0025wt%, with the balance being Ti. The β-phase transformation temperature is 1005℃. Step one employs three vacuum arc remelting processes, with the remelting process parameters being basically the same as those in Example 1; the processes and process parameters of steps two and three are basically the same as those in Example 1.

[0058] This comparative example uses three vacuum arc remelting processes, which cannot effectively control the oxygen content. The oxygen content is about 0.1 wt% higher than that of the optimized process, resulting in poor low-temperature impact performance of the final titanium alloy.

[0059] Comparative Example 2: The mass percentages of each element in the titanium alloy of this comparative example are as follows: Al 6.45wt%, Sn 1.99wt%, Zr 1.98wt%, Mo 2.09wt%, W 1.04wt%, Si 0.16wt%, Re 0.12wt%, O 0.04wt%, N 0.004wt%, H < 0.001wt%, with the balance being Ti. The β-phase transformation temperature is 990℃. The processes and process parameters for steps one, two, and three are basically the same as in Example 1.

[0060] The mechanical properties of the titanium alloy specimens prepared in the above embodiments and comparative examples were tested below. The test conditions and equipment were the same, and the test results are shown in Table 1. Two parallel specimens were tested for each test item. The microstructure of the wide-temperature-range titanium alloy billet prepared in Example 1 after heat treatment is shown below. Figure 1 As shown.

[0061]

[0062] As can be seen from the data comparison in Table 1, the wide-temperature-range titanium alloys of the three embodiments have excellent comprehensive mechanical properties and impact resistance under extreme temperature cycling conditions (-253℃ to 600℃).

[0063] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0064] It will be readily understood by those skilled in the art that this invention includes any combination of the inventive description and specific embodiments outlined in the foregoing specification, as well as the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A wide-temperature-range titanium alloy with high impact resistance, characterized in that, The mass percentages of each element in the wide-temperature-range titanium alloy are as follows: Al 6.2-7.2wt%, Sn 1.5-2.5wt%, Zr 2.8-3.8wt%, Mo 3.5-4.5wt%, W 0.8-1.2wt%, Si 0.1-0.3wt%, Re 0.3-0.5wt%, O≤0.06wt%, N≤0.01wt%, H≤0.001wt%, with the balance being Ti.

2. The wide-temperature-range titanium alloy with high impact performance according to claim 1, characterized in that, Some elements in the wide-temperature-range titanium alloy must simultaneously meet the following conditions: (1) Al + Mo + 100O ≤ 16wt%, where Al, Mo, and O represent the mass percentage of the corresponding elements; (2) The Re content is negatively correlated with the sum of W+Mo content. Within the range of the sum of Re content and W+Mo content, when the amount of Re added increases by 0.1wt%, the amount of W+Mo added decreases by 0.5-1.0wt%.

3. A method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 1 or 2, characterized in that, The preparation method includes the following steps in sequence: Step 1: Prepare round titanium alloy ingots using a melting process that combines electron beam cold hearth furnace melting and vacuum consumable melting. Step 2: Forge or combine forging and rolling to deform the prepared round titanium alloy ingot to obtain the titanium alloy billet of the desired shape. Step 3: The obtained titanium alloy billet is subjected to solution treatment and aging treatment in sequence to finally obtain a wide-temperature-range titanium alloy with high impact performance.

4. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 3, characterized in that, In step one, during the smelting stage, the titanium alloy raw materials are added as follows: Sn, Zr, Mo, Si, and W are added in the form of Ti-Sn master alloy, Al-Zr master alloy, Al-Mo master alloy, Al-Si master alloy, and Al-W master alloy, respectively; the Al portion is added in the form of Al-W master alloy, and the insufficient portion is added in the form of high-purity aluminum briquettes and / or aluminum foil; Re is added in the form of elemental rhenium; the insufficient Ti portion is added in the form of sponge titanium; the diameter of the titanium alloy ingot is 350-400 mm and the length is 1-1.2 m.

5. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 4, characterized in that, In step one, the smelting stage includes three smelting processes. The first smelting process is electron beam cold hearth furnace smelting, and the second and third smelting processes are both vacuum consumable melting.

6. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 5, characterized in that, In step one, the main parameters of the first melting process include: vacuum degree 0.01-0.5Pa, melting gun power 180-240kW, molten pool temperature 1750-1850℃, and melting time 4-8h; the main parameters of the second melting process include: vacuum degree not higher than 1Pa, current 5200-5700A, and voltage 28-34V; the main parameters of the third melting process include: vacuum degree not higher than 1Pa, current 6000-7000A, and voltage 28-34V.

7. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 6, characterized in that, In step two, the forging deformation process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and a holding time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (℃), D is the diameter of the titanium alloy ingot (mm), and K is the temperature coefficient, which is set to 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging equipment for 5-10 forging cycles, with a deformation of 30-60% per cycle. After forging, it is air-cooled to room temperature.

8. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 6, characterized in that, In step two, the forging and rolling composite deformation process is as follows: First, the titanium alloy ingot is heated in a heat treatment furnace at a temperature of (T-80℃) to (T+200℃) and a holding time of (K×D-30) to (K×D+30) min, where: T is the β-phase transformation point temperature of the titanium alloy (℃), D is the diameter of the titanium alloy ingot or the thickness of the slab (mm), and K is the temperature coefficient, which is set to 0.4-0.8 mm. -1 Then the titanium alloy ingot is transferred to forging and rolling equipment for 3-5 forging cycles and 2-3 rolling cycles, with a deformation of 30-60% per cycle. After forging and rolling, the ingot is air-cooled to room temperature.

9. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 7 or 8, characterized in that, In step three, the solution treatment temperature is 920-970℃, and the solution treatment time is 2-4 hours.

10. The method for preparing a wide-temperature-range titanium alloy with high impact performance according to claim 9, characterized in that, In step three, the aging treatment temperature is 610-630℃, and the aging treatment time is 6-8 hours.

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