High-temperature-resistant titanium alloy and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant titanium alloy and a preparation method thereof. The high-temperature-resistant titanium alloy comprises, by mass, 5.5%-6% of aluminum, 3.5%-4.2% of tin, 3.8%-4.5% of zirconium, 0.2%-0.4% of molybdenum, 0.8%-1.2% of tungsten, 0.2%-0.4% of niobium, 0.25%-0.4% of silicon, 0.4%-0.55% of manganese, 0.2%-0.5% of silicon carbide, 0.03%-0.06% of carbon and the balance titanium and inevitable impurities. The titanium alloy disclosed by the invention is excellent in room-temperature and high-temperature strength, relatively high in thermal stability, creep resistance and oxidation resistance and relatively high in high-temperature resistance, the room-temperature tensile strength is greater than 1100MPa, the high-temperature tensile strength at the temperature of 650 DEG C is greater than 650MPa, and the high-temperature tensile strength at the temperature of 750 DEG C is greater than 450MPa.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, and particularly relates to a high-temperature resistant titanium alloy and its preparation method. Background Technology

[0002] Titanium alloys, due to their low density, excellent specific strength and stiffness, and superior high-temperature performance, have been widely used in the aerospace field. However, titanium alloys have relatively poor high-temperature oxidation resistance compared to nickel-based superalloys, with their maximum operating temperature around 650℃. With the increasing demand for high-temperature resistant, high-strength titanium alloy materials in aircraft engines, gas turbines, and other equipment, traditional titanium alloys (such as TC4 and TA15), while exhibiting excellent overall performance at medium and low temperatures, show a rapid decline in strength and creep resistance at temperatures above 600℃, making them unsuitable for long-term, high-temperature service. Therefore, developing high-strength titanium alloys with a wider operating temperature range has become an important direction in current materials research.

[0003] Currently, the development of high-temperature and high-strength titanium alloys mainly focuses on optimizing their microstructure through microalloying and heat treatment processes to improve their high-temperature stability and creep resistance. However, existing alloys often fail to balance material machinability and process complexity while improving performance, resulting in high manufacturing costs and poor product consistency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a high-temperature resistant titanium alloy that can maintain good strength at a temperature of 650°C, and to realize its efficient and stable preparation method.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A high-temperature resistant titanium alloy, comprising the following components by mass percentage: aluminum 5.5-6%, tin 3.5-4.2%, zirconium 3.8-4.5%, molybdenum 0.2-0.4%, tungsten 0.8-1.2%, niobium 0.2-0.4%, silicon 0.25-0.4%, manganese 0.4-0.55%, silicon carbide 0.2-0.5%, carbon 0.03-0.06%, with the balance being titanium and unavoidable impurities; The high-temperature resistant titanium alloy is prepared by melting, hot forging and heat treatment; The hot forging process involves heating the titanium alloy after billet preparation to the α+β two-phase region and performing repeated upsetting and drawing forging. Specifically, it includes three stages: heating to 1000~1020℃ and performing upsetting and drawing forging 2~4 times; heating to 950~980℃ and performing upsetting and drawing forging 2~4 times; and heating to 930~940℃ and performing upsetting and drawing forging 1~3 times.

[0006] As a further improvement, the silicon carbide particle size is 10~20μm.

[0007] As a further improvement, the high-temperature resistant titanium alloy comprises the following components by mass percentage: 5.6% aluminum, 4% tin, 4% zirconium, 0.3% molybdenum, 1% tungsten, 0.3% niobium, 0.3% silicon, 0.5% manganese, 0.2-0.5% silicon carbide, 0.05% carbon, with the balance being titanium and unavoidable impurities.

[0008] The present invention provides a method for preparing the aforementioned high-temperature resistant titanium alloy, comprising the following steps: (1) The alloy raw materials are mixed and pressed into electrode blocks, and then melted to obtain a cast alloy billet; (2) The cast alloy billet is subjected to a blanking process and then hot forging to obtain a densified alloy bar. The hot forging process involves heating the titanium alloy after billet preparation to the α+β two-phase region and performing repeated upsetting and drawing forging. Specifically, it includes three stages: heating to 1000~1020℃ and performing upsetting and drawing forging 2~4 times; heating to 950~980℃ and performing upsetting and drawing forging 2~4 times; and heating to 930~940℃ and performing upsetting and drawing forging 1~3 times. (3) The densified alloy rod is placed in a resistance furnace with a protective atmosphere for heat treatment to obtain a high-temperature resistant titanium alloy rod.

[0009] As a further improvement, the billet treatment in step (2) includes: heating the cast alloy billet to a single-phase region of 1190℃~1220℃ for homogenization treatment, and then repeatedly upsetting, drawing and forging 2 to 6 times.

[0010] As a further improvement, in the billet opening process described in step (2), the forging ratio per forging cycle is not less than 2, the initial forging temperature is ≥1090℃, and the final forging temperature is ≥980℃.

[0011] As a further improvement, in the hot forging process described in step (2), the forging ratio of each forging is not less than 2, and the total forging ratio is not less than 4.

[0012] As a further improvement, the hot forging process in step (2) includes: 1) heating to 1000~1020℃, repeatedly upsetting and drawing forging 2~4 times, with a forging ratio of not less than 2.5 per forging and a total forging ratio of not less than 6, and a final forging temperature of not less than 850℃; 2) heating to 950~980℃, repeatedly upsetting and drawing forging 2~4 times, with a forging ratio of not less than 2 per forging and a total forging ratio of not less than 4, and a final forging temperature of not less than 810℃; 3) heating to 930~940℃, repeatedly upsetting and drawing forging 1~3 times, with a forging ratio of not less than 2.5 per forging and a total forging ratio of not less than 6, and a final forging temperature of not less than 780℃.

[0013] As a further improvement, the heat treatment in step (3) involves first performing a solution treatment on the bar, then oil cooling the bar, followed by artificial aging treatment, and finally air cooling the bar.

[0014] As a further improvement, the temperature for the solution treatment in step (3) is 900-1025℃; and the temperature for the artificial aging treatment is 550-600℃.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The high-temperature resistant titanium alloy of this invention, through the synergistic effect of various elements and strict control of their content, and with the preparation process and parameters matched to each alloying element, maximizes the effect of each element. The resulting alloy has a bimodal microstructure, exhibiting excellent room temperature and high temperature strength, strong thermal stability, creep resistance, oxidation resistance, and high temperature resistance. It also possesses a high tensile strength exceeding 1100 MPa at room temperature, greater than 650 MPa at 650°C, and greater than 450 MPa at 750°C. The preparation method of this invention is low-cost and produces products with good consistency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0017] Figure 1 This is a 200x SEM image of the titanium alloy prepared in Example 1. Figure 2 This is a 500x SEM image of the titanium alloy prepared in Example 1; Figure 3 This is a 200x SEM image of the titanium alloy prepared in Example 2; Figure 4 This is a 500x SEM image of the titanium alloy prepared in Example 2. Detailed Implementation

[0018] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0019] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0020] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0021] In some specific embodiments, the high-temperature resistant titanium alloy of the present invention comprises the following components by mass percentage: aluminum 5.5-6%, tin 3.5-4.2%, zirconium 3.8-4.5%, molybdenum 0.2-0.4%, tungsten 0.8-1.2%, niobium 0.2-0.4%, silicon 0.25-0.4%, manganese 0.4-0.55%, silicon carbide 0.2-0.5%, carbon 0.03-0.06%, with the balance being titanium and unavoidable impurities. The silicon content excludes silicon from silicon carbide, and the carbon content excludes carbon from silicon carbide.

[0022] In this alloy, manganese primarily increases the alloy's strength and hardness, improves corrosion resistance and fatigue resistance, and enhances weldability and machinability. Manganese concentrates at the interfaces, acting as a pinning reinforcement. Furthermore, manganese possesses good solid solution strengthening capabilities and exhibits some oxidation resistance. At high temperatures, it enhances the oxidation resistance and high-temperature strength of titanium alloys, thus meeting application requirements at 650℃. Compared to expensive tantalum, manganese is a low-cost element. By introducing manganese into the alloy, partially replacing the role of tantalum, not only is the dependence on rare metals reduced, optimizing the overall economics of the material, but this new alloy also becomes suitable for a wider range of industrial applications, especially showing significant advantages in large-scale production.

[0023] Sn significantly improves the oxidation resistance of high-temperature titanium alloys. Its main mechanism is the formation of a stable solid solution within the titanium matrix, which slows oxygen diffusion and inhibits the growth rate of the oxide film on the titanium alloy surface. In high-temperature oxidizing environments, Sn enhances the density and stability of the oxide film, preventing peeling and cracking, allowing the alloy to maintain good surface integrity even under prolonged high-temperature conditions. Sn is an important solid solution strengthening element in titanium alloys; it increases the strength of titanium alloys by inducing lattice distortion through solid solution in the α-phase lattice. Sn has a larger atomic radius than titanium, and its addition to titanium alloys causes a significant lattice distortion effect, hindering dislocation movement and increasing the yield strength and tensile strength of the titanium alloy.

[0024] The introduction of SiC particles in this invention significantly improves the high-temperature strength and creep resistance of the alloy. In high-temperature environments above 650°C, SiC, as a reinforcing phase, effectively hinders dislocation movement, thereby improving the strength and stability of the material. This makes SiC-reinforced titanium alloys exhibit superior mechanical properties at high temperatures compared to traditional titanium alloys, particularly excelling in aerospace and high-temperature industrial applications. Secondly, SiC possesses excellent corrosion resistance and thermal stability. Compared to some traditional alloying elements, SiC exhibits a significantly lower oxidation rate in high-temperature environments, thus improving the alloy's oxidation resistance and extending its service life. Furthermore, the introduction of SiC particles effectively improves the microstructure of the titanium alloy, enhancing its uniformity and stability, thereby strengthening its overall performance. However, when introducing SiC particles as a reinforcing phase into titanium alloys, the compatibility between the particles and the titanium matrix, as well as the interfacial bonding strength, must be considered. Poor interfacial bonding may lead to a decline in the performance of the composite material under high-temperature conditions. In addition, the uniformity and size of the SiC particle distribution also have a significant impact on the final alloy performance. By using the SiC particle addition range and size requirements of this invention, and employing the process described herein, poor interfacial bonding can be avoided.

[0025] Within the scope of this invention, the present invention achieves maximum solid solution strengthening and precipitation strengthening by controlling the Al equivalent [Al]eq≈8-9%, containing Al elements at the Al equivalent limit, increasing the phase transformation point, and utilizing α2 phase precipitation strengthening. The electron concentration is controlled at the limit of approximately 2.1, achieving precipitation strengthening without reducing plasticity. The Mo equivalent [Mo]eq is controlled within the range of ≈0.5-1%, achieving solid solution strengthening without reducing thermal strength. A relatively high content of neutral elements Sn and Zr is used to solid solution strengthen the α phase. An appropriate content of Si elements is included, with solid solution strengthening and silicide precipitation improving creep properties. An appropriate content of weakly isomorphous elements such as Mn, Nb, and W is included to improve the alloy's plasticity and fracture toughness.

[0026] This invention uses manganese instead of tantalum and adds a small amount of SiC to achieve low cost while maintaining high strength. By rationally designing the alloy composition and process parameters, titanium alloys can maintain excellent mechanical properties at a high temperature of 650℃.

[0027] In some specific embodiments, the method for preparing the high-temperature resistant titanium alloy of the present invention includes the following steps: (1) The alloy raw materials are mechanically mixed and pressed into electrode blocks, and then melted to obtain cast alloy billets (titanium alloy ingots).

[0028] This invention does not specifically limit the type of alloy raw material; alloy raw materials well known to those skilled in the art, preferably titanium alloys that can yield the target composition, are used. Before smelting, it is preferable to grind and ultrasonically clean the alloy raw material.

[0029] Preferably, titanium is selected as 0a grade sponge titanium with a particle size of 3mm to 12.7mm; zirconium is added in the form of sponge zirconium; aluminum is added in the form of master alloy and high-purity aluminum; tin is added in the form of high-purity Ti-Sn master alloy; molybdenum is added in the form of Al-Mo master alloy; silicon is added in the form of Al-Si master alloy; tungsten is added in the form of Al-W master alloy; silicon carbide is powder with a particle size of about 15μm (10~20μm); and carbon is added in the form of carbon powder. The remaining elements are selected as master alloys with low impurity content and melting point, density, and particle size close to the base metal.

[0030] Preferably, the density of the electrode block is 3.4~3.63 g / cm³. 3 Higher density electrode blocks are less prone to breakage and detachment during the smelting process, thus effectively reducing the risk of segregation and inclusions during smelting.

[0031] Preferably, during smelting, the smelting temperature is controlled at 1890-1910℃ to ensure that the alloy is completely melted and reaches a stable metallurgical state. Multiple electrode blocks are stacked and welded into consumable electrodes, and the alloy raw materials are repeatedly smelted 3-4 times in a vacuum consumable electrode arc melting furnace to improve smelting uniformity and material purity.

[0032] (2) The cast alloy billet is subjected to high-temperature blanking treatment and then hot forging treatment to obtain a dense alloy bar.

[0033] High-temperature forging treatment: Preferably, before forging, the as-cast alloy billet is heated and held at a certain temperature, and then hot forging is performed. More preferably, the as-cast alloy billet is heated to the single-phase region of 1190℃~1220℃ for homogenization treatment, and then repeatedly upsetting and drawing forging 2~6 times, with a forging ratio of not less than 2 per forging, a starting forging temperature ≥1090℃, and a final forging temperature ≥980℃. Beveling is performed before forging at a rate of 30~65mm. Upsetting deformation is ≥40%.

[0034] After obtaining the as-cast alloy billet, the present invention performs heat preservation treatment on it, and then performs billet processing and forging deformation. On the one hand, it can densify the alloy billet, obtain a dense alloy billet, and improve its internal quality; on the other hand, it can maintain a high temperature of titanium alloy ingot during the deformation process, thereby achieving sufficient hot deformation.

[0035] Hot forging treatment: Preferably, the titanium alloy (titanium alloy forging billet) after billet preparation is heated to the α+β two-phase region and subjected to repeated upsetting and drawing forging, with the number of forging cycles controlled between 4 and 8. The deformation amount (forging ratio) per forging cycle is not less than 2, and the total forging ratio is not less than 4, to ensure the uniformity of the alloy's microstructure and the stability of its properties. During the final forging process, the final forging temperature of the billet should not be too low to avoid increased brittleness of the material due to low-temperature deformation, thereby obtaining excellent high-temperature mechanical properties.

[0036] More preferably, the forging in the α+β two-phase region is divided into three stages: 1) 1000~1020℃, repeated upsetting and drawing forging 2~4 times, the forging ratio of the forging billet per forging is not less than 2.5, the total forging ratio is not less than 6, and the final forging temperature is not less than 850℃; 2) 950~980℃, repeated upsetting and drawing forging 2~4 times, the forging ratio of the forging billet per forging is not less than 2, the total forging ratio is not less than 4, and the final forging temperature is not less than 810℃; 3) 930~940℃, repeated upsetting and drawing forging 1~3 times, the forging ratio of the forging billet per forging is not less than 2.5, the total forging ratio is not less than 6, and the final forging temperature is not less than 780℃.

[0037] The hot forging deformation method employed in this invention facilitates the breaking down of Widmanstätten lath grains, causing them to spheroidize into the primary α phase. Subsequent heat treatment transforms the lamellar α and partially equiaxed α grains in the original microstructure into the β phase. During subsequent air cooling, the lamellar α precipitates from the β phase, and the equiaxed α grains grow, resulting in a typical bimodal microstructure. Hot forging helps to break down coarse grains, refine the original β grain microstructure, and eliminate microstructural defects in the material, thereby significantly improving the overall strength of the alloy.

[0038] Further optimization involves rounding the forged bar stock.

[0039] (3) The densified alloy rod is placed in a resistance furnace with a protective atmosphere for heat treatment to obtain a high-temperature resistant titanium alloy rod.

[0040] Preferably, during heat treatment, the bar is first subjected to solution treatment, then oil-cooled to room temperature, then artificially aged, and finally air-cooled to room temperature.

[0041] Further preferably, during solution treatment, the temperature is 900-1025℃, the heating rate is 6-15℃ / min, and the holding time is 180-360min. During the solution treatment, it is preferable to perform the holding treatment under a protective atmosphere, specifically argon. This solution treatment process helps to eliminate residual stress caused by hot deformation as much as possible, thereby improving the alloy's strength while maintaining a certain degree of plasticity, and further optimizing the alloy's performance control.

[0042] Further optimization involves artificial aging treatment at a temperature of 550-600℃ for 6-8 hours, followed by air cooling.

[0043] The heat treatment of this invention can also eliminate structural defects and improve the strength of the alloy.

[0044] This invention combines the synergistic effects of various elements. The addition of carbon can expand the α+β two-phase region and increase the processing window of high-temperature titanium alloys, making it relatively easy to control the content of primary α phase. Through special heat treatment, a mixed structure of 10~15% primary α phase can be obtained, which can also coordinate the thermal stability, creep performance and fatigue performance of the alloy, and improve the overall performance of the alloy.

[0045] The high-temperature resistant titanium alloy prepared by this invention has a bimodal microstructure, consisting of an equiaxed primary α phase and a lath-like secondary α phase.

[0046] The smelting process of this invention can strictly control the content of harmful impurity elements such as O, Fe, and Ni.

[0047] Example 1: Step 1: Small-particle-size 0a grade sponge titanium, zirconium in the form of sponge zirconium, aluminum in the form of master alloy and high-purity aluminum, tin in the form of high-purity Ti-Sn master alloy, molybdenum in the form of Al-Mo master alloy, silicon in the form of Al-Si master alloy, tungsten in the form of Al-W master alloy, silicon carbide in powder form with a particle size of around 15μm, carbon in the form of carbon powder, and the remaining elements in the form of master alloys. The proportions are as follows: 5.6 wt.% aluminum, 4 wt.% tin, 4 wt.% zirconium, 0.3 wt.% molybdenum, 1 wt.% tungsten, 0.3 wt.% niobium, 0.3 wt.% silicon, 0.5 wt.% manganese, 0.5 wt.% silicon carbide, 0.05 wt.% carbon, with the balance being titanium. After weighing and mixing, a mixed metal powder is obtained.

[0048] Step 2: Press the uniformly mixed ingredients into electrodes using a hydraulic press. The density of the electrode blocks is 3.45~3.5 g / cm³. 3 Multiple electrode blocks are stacked and welded into consumable electrodes. The alloy raw materials are repeatedly melted four times in a vacuum consumable electrode arc melting furnace at a temperature of 1890~1910℃ to ensure the uniformity of the ingot composition. After the ingot melting is completed, the riser is removed. Step 3: Using a resistance furnace, heat the high-temperature resistant titanium alloy ingot to 1190℃ in the single-phase region for homogenization treatment. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the ingot 6 times, with a forging ratio of not less than 2 per forging. The initial forging temperature is ≥1090℃, and the final forging temperature is ≥990℃. Before forging, chamfer the edges at a speed of 50 mm / s (upsetting deformation is 50%, and the drawing circumference should match the height-to-diameter ratio of 2:1), upsetting the 690×1320 cm ingot to 590±10 cm and drawing it to 620×L cm.

[0049] Step 4: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 1000℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet three times. The forging ratio of each forging is not less than 2.5, the total forging ratio is not less than 6, and the final forging temperature is not less than 850℃.

[0050] Step 5: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 960℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet three times. The forging ratio of each forging is not less than 2, the total forging ratio is not less than 4, and the final forging temperature is not less than 810℃.

[0051] Step 6: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 930℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet twice. The forging ratio of each forging is not less than 2.5, the total forging ratio is not less than 6, and the final forging temperature is not less than 780℃.

[0052] Step 7: Heat-treat the hot-forged titanium alloy bar by solution treatment at 950°C, with a heating rate of 10°C / min and a holding time of 360min. After heat treatment, the bar is cooled to room temperature by oil cooling, and then artificially aged at 550°C for 6 hours before being air-cooled to room temperature.

[0053] Step 8: Take radial samples of the heat-treated titanium alloy and perform tensile tests according to room temperature tensile (GB / T 228.1-2021) and high temperature tensile (GB / T 228.2-2015), with at least 3 tests at each temperature.

[0054] Example 2: Step 1: Small-particle-size 0a grade sponge titanium, zirconium (in sponge zirconium form), aluminum (in the form of master alloy and high-purity aluminum), tin (in the form of high-purity Ti-Sn master alloy), molybdenum (in the form of Al-Mo master alloy), silicon (in the form of Al-Si master alloy), tungsten (in the form of Al-W master alloy), silicon carbide (in powder form with a particle size of around 15μm), carbon (in the form of carbon powder), and other elements (in the form of master alloys) are added. The proportions are as follows: 5.6 wt.% aluminum, 4 wt.% tin, 4 wt.% zirconium, 0.3 wt.% molybdenum, 1 wt.% tungsten, 0.3 wt.% niobium, 0.3 wt.% silicon, 0.2 wt.% silicon carbide, 0.5 wt.% manganese, 0.05 wt.% carbon, with the balance being titanium. After weighing and mixing, a mixed metal powder is obtained.

[0055] Step 2: Press the uniformly mixed ingredients into electrodes using a hydraulic press. The density of the electrode blocks is 3.40-3.55 g / cm³. 3Multiple electrode blocks are stacked and welded into consumable electrodes. The alloy raw materials are repeatedly melted three times in a vacuum consumable electrode arc melting furnace at a temperature of 1890~1910℃ to ensure the uniformity of the ingot composition. After the ingot melting is completed, the riser is removed. Step 3: Using a resistance furnace, heat the high-temperature resistant titanium alloy ingot to 1200℃ in the single-phase region for homogenization treatment. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the ingot five times, with a forging ratio of not less than 2.5 per forging. The initial forging temperature should be ≥1100℃, and the final forging temperature should be ≥1000℃. Before forging, chamfer the edges at a speed of 30 mm / s (upsetting deformation should be 50%, and the drawing circumference should match the height-to-diameter ratio of 2:1), upsetting the 690×1320cm ingot to 590±10cm and drawing it to 620×Lcm.

[0056] Step 4: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 1000℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet twice. The forging ratio of each forging is not less than 3, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃.

[0057] Step 5: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 960℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet three times. The forging ratio of each forging is not less than 2, the total forging ratio is not less than 4, and the final forging temperature is not less than 810℃.

[0058] Step 6: Using a resistance furnace, heat the high-temperature resistant titanium alloy after billet preparation to the α+β two-phase region at a temperature of 930℃. Then, use a high-speed forging machine or hydraulic press to repeatedly upset and draw the billet twice. The forging ratio of each forging is not less than 2.5, the total forging ratio is not less than 6, and the final forging temperature is not less than 780℃.

[0059] Step 7: Heat-treat the hot-forged titanium alloy bar by solution treatment at 900°C, with a heating rate of 10°C / min and a holding time of 360min. After heat treatment, the bar is cooled to room temperature by oil cooling, and then artificially aged at 600°C for 8 hours before being air-cooled to room temperature.

[0060] Step 8: Take axial samples of the heat-treated titanium alloy and perform tensile tests according to room temperature tensile (GB / T 228.1-2021) and high temperature tensile (GB / T 228.2-2015), with at least 3 tests at each temperature.

[0061] Comparative Example 1: The only difference from Example 1 is that silicon carbide is not added.

[0062] Comparative Example 2: The only difference from Example 1 is that the amount of silicon carbide added is 0.8%, and the particle size is 25-40 μm.

[0063] Comparative Example 3: The only difference from Example 1 is that step 5 is omitted.

[0064] Figure 1 This is a 200x SEM image of the titanium alloy prepared in Example 1. Figure 2 This is a 500x SEM image of the titanium alloy prepared in Example 1. (From...) Figure 1 and Figure 2 It can be seen that the titanium alloy obtained in Example 1 mainly consists of a bimodal structure, in which SiC particles are dispersedly distributed as reinforcing phases. The primary α phase is abundant. Table 1 shows the room temperature and high temperature tensile properties of the high-temperature titanium alloy in Example 1.

[0065] Figure 3 This is a 200x SEM image of the titanium alloy prepared in Example 2. Figure 4 This is a 500x SEM image of the titanium alloy obtained in Example 2. Figures 3-4 It can be seen that the titanium alloy obtained in Example 2 mainly consists of a bimodal structure, in which SiC particles are dispersed as reinforcing phases. The amount of primary α phase is relatively small. Table 2 shows the room temperature and high temperature tensile properties of the high-temperature titanium alloy in Example 2.

[0066] Table 3-5 shows the room temperature and high temperature tensile properties of the high-temperature titanium alloys in Comparative Examples 1-3.

[0067] Table 1. Room temperature and high temperature tensile properties of the high-temperature titanium alloy in Example 1

[0068] Table 2. Room temperature and high temperature tensile properties of the high-temperature titanium alloy in Example 2

[0069] Table 3. Room temperature and high temperature tensile properties of the high-temperature titanium alloy in Comparative Example 1

[0070] Table 4. Room temperature and high temperature tensile properties of the high-temperature titanium alloy in Comparative Example 2

[0071] Table 5. Room temperature and high temperature tensile properties of the high-temperature titanium alloy in Comparative Example 3

[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A high-temperature resistant titanium alloy, characterized in that, The high-temperature resistant titanium alloy comprises the following components by mass percentage: aluminum 5.5-6%, tin 3.5-4.2%, zirconium 3.8-4.5%, molybdenum 0.2-0.4%, tungsten 0.8-1.2%, niobium 0.2-0.4%, silicon 0.25-0.4%, manganese 0.4-0.55%, silicon carbide 0.2-0.5%, carbon 0.03-0.06%, with the balance being titanium and unavoidable impurities; The high-temperature resistant titanium alloy is prepared by melting, hot forging and heat treatment; The hot forging process involves heating the titanium alloy after billet preparation to the α+β two-phase region and performing repeated upsetting and drawing forging. Specifically, it includes three stages: heating to 1000~1020℃ and performing upsetting and drawing forging 2~4 times; heating to 950~980℃ and performing upsetting and drawing forging 2~4 times; and heating to 930~940℃ and performing upsetting and drawing forging 1~3 times.

2. The high-temperature resistant titanium alloy according to claim 1, characterized in that, The silicon carbide particle size is 10~20μm.

3. The high-temperature resistant titanium alloy according to claim 1, characterized in that, The high-temperature resistant titanium alloy comprises the following components by mass percentage: 5.6% aluminum, 4% tin, 4% zirconium, 0.3% molybdenum, 1% tungsten, 0.3% niobium, 0.3% silicon, 0.5% manganese, 0.2-0.5% silicon carbide, 0.05% carbon, with the balance being titanium and unavoidable impurities.

4. A method for preparing the high-temperature resistant titanium alloy according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) The alloy raw materials are mixed and pressed into electrode blocks, and then melted to obtain a cast alloy billet; (2) The cast alloy billet is subjected to a blanking process and then hot forging to obtain a densified alloy bar. The hot forging process involves heating the titanium alloy after billet preparation to the α+β two-phase region and performing repeated upsetting and drawing forging. Specifically, it includes three stages: heating to 1000~1020℃ and performing upsetting and drawing forging 2~4 times; heating to 950~980℃ and performing upsetting and drawing forging 2~4 times; and heating to 930~940℃ and performing upsetting and drawing forging 1~3 times. (3) The densified alloy rod is placed in a resistance furnace with a protective atmosphere for heat treatment to obtain a high-temperature resistant titanium alloy rod.

5. The preparation method according to claim 4, characterized in that, Step (2) includes the following: heating the cast alloy billet to a single-phase region of 1190℃~1220℃ for homogenization treatment, and then repeatedly upsetting, drawing and forging 2 to 6 times.

6. The preparation method according to claim 5, characterized in that, In the billet opening process described in step (2), the forging ratio per forging cycle is not less than 2, the initial forging temperature is ≥1090℃, and the final forging temperature is ≥980℃.

7. The preparation method according to claim 4, characterized in that, In step (2), the hot forging process shall have a forging ratio of not less than 2 per forging and a total forging ratio of not less than 4.

8. The preparation method according to claim 4, characterized in that, The hot forging process in step (2) includes: 1) heating to 1000~1020℃, repeatedly upsetting and drawing forging 2~4 times, with a forging ratio of not less than 2.5 per forging and a total forging ratio of not less than 6, and a final forging temperature of not less than 850℃; 2) heating to 950~980℃, repeatedly upsetting and drawing forging 2~4 times, with a forging ratio of not less than 2 per forging and a total forging ratio of not less than 4, and a final forging temperature of not less than 810℃; 3) heating to 930~940℃, repeatedly upsetting and drawing forging 1~3 times, with a forging ratio of not less than 2.5 per forging and a total forging ratio of not less than 6, and a final forging temperature of not less than 780℃.

9. The preparation method according to claim 4, characterized in that, The heat treatment described in step (3) involves first performing a solution treatment on the bar, then oil cooling the bar, followed by artificial aging treatment, and finally air cooling the bar.

10. The preparation method according to claim 9, characterized in that, During the solution treatment in step (3), the temperature is 900-1025℃; during the artificial aging treatment, the temperature is 550-600℃.

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