A titanium-aluminum alloy blade with an service temperature of 850℃, its preparation method and application

Abstract

This invention belongs to the field of high-temperature structural materials and powder metallurgy forming technology. Specifically, it discloses a titanium-aluminum alloy blade with an service temperature of 850℃, its preparation method, and its application. The preparation method includes: 1) preparing titanium-aluminum alloy powder containing specific components (Ti, Al, Ta, Nb, W, and controlling the O and N content in impurities), and sieving the powder to a set particle size; 2) packing and degassing; 3) performing staged temperature-controlled hot isostatic pressing on the packed powder packing; 4) machining to remove the packing to obtain the titanium-aluminum alloy blade. The blade prepared by this invention is near-net-shape and requires no complex heat treatment, significantly shortening the preparation cycle and improving preparation efficiency. The prepared titanium-aluminum alloy blade has a room temperature elongation ≥1.3%, a yield strength ≥340MPa at 850℃, excellent oxidation resistance and service life, fully meeting the requirements of aero-engines and gas turbines for high-temperature service and lightweight blades.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature structural materials and powder metallurgy forming technology, specifically relating to a titanium-aluminum alloy blade with an service temperature of 850℃, its preparation method and application, and is particularly suitable for the manufacture of lightweight hot-end components for high-end equipment such as aero engines and gas turbines. Background Technology

[0002] Titanium-aluminum (TiAl) alloys are characterized by their low density (approximately 4.0 g / cm³). 3 With its high specific strength and excellent high-temperature oxidation resistance, Ti-48Al-2Cr-2Nb has become an ideal material to replace nickel-based superalloys, showing broad application prospects in high-end equipment such as low-pressure turbine blades for aero-engines and gas turbine blades. Weight reduction can achieve equipment upgrades and performance improvements. For example, the Ti-48Al-2Cr-2Nb (at.%) alloy was successfully applied to the sixth and seventh stages of the low-pressure turbine blades in the GEnX engine as early as 2012, improving fuel efficiency by approximately 20%, reducing nitrogen oxide emissions by 80%, and reducing noise by 50%, making it a commercially successful TiAl alloy. With the development of additive manufacturing technology, in 2020, Ti-48Al-2Cr-2Nb alloy blades prepared using additive manufacturing processes were applied in the GE9X engine. The TNM alloy (Ti-43.5Al-4Nb-1Mo-0.1B, at.%) was also applied by Pratt & Whitney to a geared turbofan engine in 2014.

[0003] However, Ti-48Al-2Cr-2Nb alloys have poor high-temperature performance and oxidation resistance, limiting their application to around 650℃. Although TNM alloys and high-Nb titanium-aluminum alloys possess excellent high-temperature mechanical properties and oxidation resistance, their microstructure becomes unstable after long-term high-temperature service, easily leading to performance degradation or even failure, thus making them unsuitable for applications above 750℃.

[0004] In casting, hypercrystallized titanium-aluminum alloys with low Nb and Ta content exhibit good oxidation resistance and microstructure stability at 850℃. However, casting alloys require high-temperature long-term homogenization and cyclic heat treatment or multi-step heat treatment for microstructure control. The complex heat treatment methods are not conducive to engineering applications and are difficult to avoid casting defects and compositional segregation. For complex-shaped parts such as blades, there are also problems such as high machining difficulty and low yield.

[0005] Powder metallurgy technology can avoid defects such as component segregation and inconsistent microstructure that occur during casting, eliminate porosity and shrinkage cavities, and directly produce near-net-shape products. It has significant advantages in forming and homogenization for titanium-aluminum alloys with poor plasticity, difficult machining, and the addition of refractory elements. Based on this, a specific short-process hot isostatic pressing stage temperature control strategy can meet service performance requirements. The short process and simple procedures facilitate engineering application and hold promise for use in the manufacture of low-pressure turbine blades made of titanium-aluminum alloys for next-generation engines.

[0006] Inventions with application numbers 201710305177.6 and 202410307434.X disclose casting titanium-aluminum alloys suitable for 800℃. These inventions target high-Al, Nb-rich casting γ-TiAl alloys with peritectic solidification, improving strength while ensuring good oxidation resistance and casting performance, making them suitable for manufacturing hot-end components such as low-pressure turbine blades for aerospace vehicles. However, this method involves the addition of Nb and Ta elements with high density, making it difficult to avoid compositional segregation and inhomogeneous microstructure in the casting alloy. Obtaining a uniform and fine ideal microstructure requires complex heat treatment control, which is not conducive to engineering applications.

[0007] The invention application with application number 20201043700.1 discloses a method for preparing powder metallurgy titanium-aluminum alloy parts. The method involves mechanically mixing raw material powders, cold isostatic pressing, hot pressing and sintering, and finally hot isostatic pressing for densification. However, the oxygen content can only be controlled to no more than 0.15 wt.%, which is not conducive to high-temperature service performance.

[0008] In view of this, this invention is hereby proposed. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a titanium-aluminum alloy blade with an operating temperature of 850℃, its preparation method, and its application. It is mainly used to solve the problems of insufficient performance, complex process, and high difficulty in blade processing of existing titanium-aluminum alloys at high temperatures. This invention achieves stable service of titanium-aluminum alloy blades at a high temperature of 850℃ by optimizing alloy composition design and short-process powder metallurgy, while significantly improving the efficiency of engineering preparation.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing a titanium-aluminum alloy blade with an service temperature of 850°C, the method comprising the following steps:

[0012] Step 1: Preparation of titanium-aluminum alloy powder

[0013] First, titanium-aluminum alloy powder is prepared using a plasma rotating electrode process. The composition of the titanium-aluminum alloy powder includes: 45-48.5 at.% Al, 1-3 at.% Ta, 1-3 at.% Nb, and 0-0.5 at.% W, with the remainder being Ti and unavoidable impurities. The impurities are controlled to have O ≤ 600 ppm and N ≤ 200 ppm. Then, the titanium-aluminum alloy powder with a set particle size is obtained by sieving.

[0014] Step 2: Packaging and degassing

[0015] A casing was pre-designed and manufactured according to the specifications of the titanium-aluminum alloy blades. The titanium-aluminum alloy powder obtained from the sieving in step 1 was loaded into the casing. During the powder loading process, vibration was performed while CO gas was introduced, and the casing was kept warm to remove gas. Subsequently, the temperature was maintained and a vacuum was drawn to ≤1×10⁻⁶. -3 Pa;

[0016] Step 3: Perform staged temperature-controlled hot isostatic pressing on the package after powder filling;

[0017] Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blades.

[0018] Further, in step 1, the titanium-aluminum alloy powder composition is 46.5–48.3 at.% Al, 1.3–3 at.% Ta, 1–2.8 at.% Nb, 0.1–0.5 at.% W, with the remainder being Ti and unavoidable impurities.

[0019] Furthermore, in step 1, the impurities in the titanium-aluminum alloy powder are O≤500ppm and N≤150ppm.

[0020] Furthermore, in step 1, the particle size of the titanium-aluminum alloy powder obtained by sieving is 53μm to 150μm.

[0021] Furthermore, in step 2, the casing material is pure titanium.

[0022] Furthermore, in step 2, the flow rate of the introduced CO gas is 50 mL / min to 100 mL / min;

[0023] During the heat preservation and degassing process, the temperature is set to 600℃~700℃ and the time is set to 0.5h~1.5h.

[0024] Furthermore, in step 3, the hot isostatic pressing process is divided into the following three stages:

[0025] First stage: In the α+γ two-phase region, the temperature is 1250℃~1300℃, the pressure is 110MPa~160MPa, and the temperature is maintained for 2h~5h.

[0026] Second stage: Heat up to the α single-phase region at 1350℃~1420℃, hold for 15min~40min, and then furnace cool to the α+γ two-phase region at 1250℃~1320℃.

[0027] The third stage: rapidly cool to 800℃~900℃ at a cooling rate of 15℃ / min~25℃ / min, hold for 3h~5h to relieve stress, and then furnace cool to room temperature.

[0028] It should be noted that this invention innovatively adds specific proportions of Ta, Nb, and W elements to an Al-containing hypercrystallized titanium-aluminum alloy system. Ta, Nb, and W synergistically enhance the alloy's high-temperature strength, creep resistance, and oxidation resistance, with Ta and Nb showing significant effects, and Ta exhibiting the best results. Ta can also reduce interfacial energy, promote metastable microstructure transformation, and achieve grain refinement. However, high-melting-point elements are prone to causing compositional segregation, and excessive addition increases density and cost; therefore, the amount added must be strictly controlled. Furthermore, this invention uses high-purity titanium-aluminum alloy ingots prepared by vacuum arc consumable melting as raw material, combined with an ultra-high speed plasma rotating electrode process (SS-PREP). ® The powder is prepared and then formed by hot isostatic pressing. This process can effectively improve the segregation problem of Ta, Nb, and W elements, ensuring a uniform and fine microstructure. Combined with the temperature control strategy during the hot isostatic pressing stage, the microstructure transformation is precisely controlled, ultimately obtaining titanium-aluminum alloy blades with a fine near-lamellar microstructure, meeting the stringent requirements of high-temperature service at 850℃.

[0029] Secondly, the present invention also provides a titanium-aluminum alloy blade with an service temperature of 850°C, wherein the titanium-aluminum alloy blade is prepared based on the above-described preparation method.

[0030] Furthermore, the properties of the titanium-aluminum alloy blades are as follows: room temperature tensile elongation ≥1.3%, tensile yield strength at 850℃ ≥340MPa, and oxidation weight gain at 850℃ ≤0.9mg / cm². 2 850℃ / 125MPa creep life ≥130h.

[0031] Thirdly, the present invention also provides an application of the above-mentioned titanium-aluminum alloy blade, wherein the titanium-aluminum alloy blade is used in the manufacture of lightweight blades for aero-engines or gas turbines operating in a high-temperature environment of 850°C.

[0032] Specifically, the titanium-aluminum alloy blades, with their excellent high-temperature strength, creep resistance, oxidation resistance, and lightweight characteristics, can directly replace traditional nickel-based high-temperature alloy blades and are suitable for the following scenarios:

[0033] In the field of aero-engines: As low-pressure turbine blades (such as the sixth and seventh stage blades of low-pressure turbines in turbofan engines), they reduce rotational inertia by reducing weight, thereby improving the engine's thrust-to-weight ratio and fuel efficiency (10% to 15% higher than traditional alloys), while reducing nitrogen oxide emissions (more than 30% lower).

[0034] In the gas turbine field: used for high-temperature blades (such as the rear section of the compressor and turbine guide vanes), maintaining high strength while adapting to long-term high-temperature conditions, extending equipment service life and reducing maintenance costs.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] This invention significantly improves the room temperature plasticity, high temperature strength, creep performance, and oxidation resistance of hyperpericytic titanium-aluminum alloys by adding appropriate amounts of Ta, Nb, and W elements and strictly controlling the content of O and N impurities. Among them, the Ta element can achieve microstructure refinement and toughening by reducing the formation of metastable γ-phase. At the same time, the short-process powder hot isostatic pressing staged temperature control strategy effectively improves the compositional segregation problem of high melting point elements and obtains fine and uniform isotropic near-lamellar microstructure. Specifically, the first stage involves hot isostatic pressing in the α+γ two-phase region to achieve powder densification and obtain a dense titanium-aluminum alloy blade. The second stage involves short-term holding in the α single-phase region to approximately transform the microstructure of the titanium-aluminum alloy blade into an α single-phase structure, preparing for the next step of microstructure control. In the third stage, the α→α2+γ phase transformation occurs during rapid cooling from the α single-phase region to 800℃~900℃. Since the γ phase and α phase follow the Blackburn orientation relationship, six γ phase variants can be formed within a single α grain. γ lamellae precipitate in different directions, obtaining a near-lamellar structure and simultaneously refining the grains. Subsequently, the blade is held at 800℃~900℃ to eliminate internal stress and then furnace-cooled to room temperature, ultimately obtaining a titanium-aluminum alloy blade with performance meeting service requirements. This invention achieves near-net-shape forming and microstructure control through a single hot isostatic pressing process, eliminating the need for traditional complex heat treatments. This significantly shortens the preparation cycle and improves material utilization. Furthermore, the prepared blades exhibit a tensile yield strength ≥340MPa and an oxidation weight gain ≤0.9mg / cm³ at 850℃. 2 With an excellent service life of ≥130h, it breaks through the bottlenecks of insufficient high-temperature service performance and high difficulty in engineering preparation of traditional titanium-aluminum alloys, and provides an efficient and low-cost solution for the manufacturing of lightweight hot-end components of high-end equipment such as aero engines and gas turbines. Attached Figure Description

[0037] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] Figure 1 This is a flowchart of the method for preparing titanium-aluminum alloy blades according to the present invention;

[0040] Figure 2 The image shows the microstructure of titanium-aluminum alloy blade A prepared in Example 1 of this invention.

[0041] Figure 3 Microstructure of titanium-aluminum alloy blade B prepared in Example 2 of this invention;

[0042] Figure 4 The image shows the microstructure of the titanium-aluminum alloy blade prepared in Example 3 of this invention. Detailed Implementation

[0043] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0044] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0045] Please see Figure 1 The present invention provides a method for preparing a titanium-aluminum alloy blade with an service temperature of 850℃, which specifically includes the following steps:

[0046] Step 1: Preparation of titanium-aluminum alloy powder

[0047] First, titanium-aluminum alloy powder is prepared using a plasma rotating electrode process. The composition of the titanium-aluminum alloy powder includes: 45-48.5 at.% Al, 1-3 at.% Ta, 1-3 at.% Nb, and 0-0.5 at.% W, with the remainder being Ti and unavoidable impurities. The impurities are controlled to have O ≤ 600 ppm and N ≤ 200 ppm. Then, the titanium-aluminum alloy powder with a set particle size is obtained by sieving.

[0048] Specifically, in the preparation of titanium-aluminum alloy powder using the plasma rotating electrode process, the end of the titanium-aluminum alloy rod is uniformly melted. Atomized droplets are ejected from the end of the rod under centrifugal force, forming fine droplets. These droplets are rapidly cooled into spherical particles in an inert gas environment and fall into a collector at the bottom of the reaction chamber, obtaining full-size titanium-aluminum alloy powder. This powder is then sieved under an inert atmosphere to obtain titanium-aluminum alloy powder with a particle size of 53μm to 150μm. The reason for using this particle size range in this invention is as follows: if the powder particle size is too fine, it will lead to excessively high oxygen content and easily cause the formation of original particle boundaries in the powder metallurgy structure, thus affecting the performance of the parts; if the powder particle size is too coarse, it will result in excessively large initial grain size; if the powder particle size range is too wide, it will lead to poor uniformity of the powder metallurgy structure.

[0049] Preferably, the titanium-aluminum alloy powder has the following composition: 46.5-48.3 at.% Al, 1.3-3 at.% Ta, 1-2.8 at.% Nb, and 0.1-0.5 at.% W, with the remainder being Ti and unavoidable impurities, and the impurities are controlled to have O ≤ 500 ppm and N ≤ 150 ppm.

[0050] Step 2: Packaging and degassing

[0051] A casing was pre-designed and manufactured according to the specifications of the titanium-aluminum alloy blades. The titanium-aluminum alloy powder obtained from the sieving in step 1 was loaded into the casing. During the powder loading process, vibration was performed while CO gas was introduced, and the casing was kept warm to remove gas. Subsequently, the temperature was maintained and a vacuum was drawn to ≤1×10⁻⁶. -3 Pa.

[0052] Specifically, the sheath is made of pure titanium to prevent the introduction of other impurities during hot isostatic pressing. The flow rate of CO gas is 50 mL / min to 100 mL / min. During the degassing process, the temperature is set to 600℃ to 700℃ and the time is set to 0.5 h to 1.5 h to remove surface oxides. Subsequently, the temperature is maintained and a vacuum is applied until the pressure is ≤1×10⁻⁶. -3 Pa.

[0053] Step 3: Perform staged temperature-controlled hot isostatic pressing on the package after powder filling.

[0054] Specifically, the hot isostatic pressing process is divided into the following three stages:

[0055] First stage: In the α+γ two-phase region, the temperature is 1250℃~1300℃, the pressure is 110MPa~160MPa, and the temperature is held for 2h~5h. In this stage, densification is achieved while avoiding excessive grain growth.

[0056] Second stage: Heat up to the α single-phase region at 1350℃~1420℃, hold for 15min~40min, and then furnace cool to the α+γ two-phase region at 1250℃~1320℃.

[0057] The third stage: rapidly cool to 800℃~900℃ at a cooling rate of 15℃ / min~25℃ / min, hold for 3h~5h to relieve stress, and then furnace cool to room temperature.

[0058] Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blades.

[0059] To further verify the effectiveness of the present invention, the inventors conducted the following specific experiments: Example 1

[0060] This embodiment describes the preparation of a certain type of titanium-aluminum alloy blade A for aero-engines. The detailed preparation process is as follows:

[0061] 1) Titanium-aluminum alloy powder was prepared by plasma rotating electrode process and then screened under inert atmosphere (argon) to obtain titanium-aluminum alloy powder with a particle size of 53μm to 150μm.

[0062] Specifically, the composition of the titanium-aluminum alloy powder is as follows: Al content is 46.5 at.%, Ta content is 1.3 at.%, Nb content is 2.8 at.%, W content is 0.3 at.%, and the remainder is Ti and unavoidable impurities, among which the O content is 500 ppm and the N content is 150 ppm.

[0063] 2) Design and manufacture a pure titanium sheath according to the specifications of titanium-aluminum alloy blade A. Load the titanium-aluminum alloy powder obtained from sieving in step 1) into the sheath. Vibrate the sheath during loading while simultaneously introducing CO gas at a flow rate of 50 mL / min. Maintain the temperature at 650℃ for 1 hour to remove gas. After 1 hour, stop introducing CO gas and maintain the temperature at 650℃ while drawing a vacuum to 8.3 × 10⁻⁶. -4 Pa.

[0064] 3) Perform staged temperature-controlled hot isostatic pressing on the package after powder filling.

[0065] Specifically, the hot isostatic pressing process is divided into the following three stages:

[0066] First stage: In the α+γ two-phase region, the temperature is 1250℃, the pressure is 110MPa, and the holding time is 5h;

[0067] Second stage: Heat up to the α single-phase region at 1350℃, hold for 15 minutes, and then cool in the furnace to the α+γ two-phase region at 1250℃.

[0068] The third stage: rapidly cool to 800°C at a cooling rate of 15°C / min, hold at that temperature for 5 hours, and then furnace cool to room temperature.

[0069] Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blade A. Example 2

[0070] This embodiment describes the preparation of a certain type of titanium-aluminum alloy blade B for gas turbines. The detailed preparation process is as follows:

[0071] 1) Titanium-aluminum alloy powder was prepared by plasma rotating electrode process and then screened under inert atmosphere (argon) to obtain titanium-aluminum alloy powder with a particle size of 53μm to 150μm.

[0072] Specifically, the composition of the titanium-aluminum alloy powder is as follows: Al content is 47.2 at.%, Ta content is 2.2 at.%, Nb content is 1.5 at.%, W content is 0.1 at.%, and the remainder is Ti and unavoidable impurities, among which the O content is 400 ppm and the N content is 100 ppm.

[0073] 2) Design and fabricate a pure titanium sheath according to the specifications of titanium-aluminum alloy blade B. Load the titanium-aluminum alloy powder obtained from sieving in step 1) into the sheath. Vibrate the sheath during loading while simultaneously introducing CO gas at a flow rate of 75 mL / min. Maintain the temperature at 600℃ for 1.5 hours to degas. After 1.5 hours, stop introducing CO gas and maintain the temperature at 600℃ while drawing a vacuum to 9.8 × 10⁻⁶. -4 Pa.

[0074] 3) Perform staged temperature-controlled hot isostatic pressing on the package after powder filling.

[0075] Specifically, the hot isostatic pressing process is divided into the following three stages:

[0076] First stage: In the α+γ two-phase region, the temperature is 1275℃, the pressure is 135MPa, and the holding time is 3h;

[0077] Second stage: Heat up to the α single-phase region at 1385℃, hold for 25 minutes, and then cool in the furnace to the α+γ two-phase region at 1285℃.

[0078] The third stage: rapidly cool to 850°C at a cooling rate of 18°C / min, hold at that temperature for 4 hours, and then furnace cool to room temperature.

[0079] Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blade B. Example 3

[0080] This embodiment describes the preparation of a certain type of titanium-aluminum alloy blade C for aero-engines. The detailed preparation process is as follows:

[0081] 1) Titanium-aluminum alloy powder was prepared by plasma rotating electrode process and then screened under inert atmosphere (argon) to obtain titanium-aluminum alloy powder with a particle size of 53μm to 150μm.

[0082] Specifically, the composition of the titanium-aluminum alloy powder is as follows: Al content is 48.3 at.%, Ta content is 3 at.%, Nb content is 1 at.%, W content is 0.5 at.%, and the remainder is Ti and unavoidable impurities, among which the O content is 350 ppm and the N content is 60 ppm.

[0083] 2) Design and fabricate a pure titanium sheath in advance according to the specifications of titanium-aluminum alloy blade C. Load the titanium-aluminum alloy powder obtained from sieving in step 1) into the sheath. Vibrate the sheath during loading while simultaneously introducing CO gas at a flow rate of 100 mL / min. Maintain the temperature at 700℃ for degassing for 0.5 h. After 0.5 h, stop introducing CO gas and maintain a vacuum at 700℃ until a pressure of 9.2 × 10⁻⁶ is reached. -4 Pa.

[0084] 3) Perform staged temperature-controlled hot isostatic pressing on the package after powder filling.

[0085] Specifically, the hot isostatic pressing process is divided into the following three stages:

[0086] First stage: In the α+γ two-phase region, the temperature is 1300℃, the pressure is 160MPa, and the holding time is 2h;

[0087] Second stage: Heat up to the α single-phase region at 1420℃, hold for 40 minutes, and then cool in the furnace to the α+γ two-phase region at 1320℃.

[0088] The third stage: rapidly cool to 900°C at a cooling rate of 25°C / min, hold for 3 hours, and then furnace cool to room temperature.

[0089] Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blade C.

[0090] Performance testing

[0091] The internal microstructure, room temperature, and mechanical properties of the titanium-aluminum alloy blades prepared in Examples 1-3 were tested. Figures 2-4 The following table shows the scanning electron microscope microstructures of the titanium-aluminum alloy blades prepared in Examples 1-3; Table 1 below shows the mechanical property test results of the titanium-aluminum alloy blades prepared in Examples 1-3 under room temperature and high temperature conditions of 850℃.

[0092] Table 1. Test results of mechanical properties of titanium-aluminum alloy blades prepared in Examples 1-3

[0093]

[0094] pass Figures 2-4 The corresponding microstructures show that the titanium-aluminum alloy blades prepared in Examples 1-3 of this invention all possess a fine, near-lamellar stable structure. α2 lamellae and γ lamellae are arranged alternately to form lamellar clusters, with an average cluster size of approximately 100 μm to 200 μm. Fine equiaxed γ phases are distributed between the lamellar clusters. Furthermore, Table 1 shows the mechanical property test results of the titanium-aluminum alloy blades prepared in Examples 1-3, indicating that the room temperature tensile elongation is ≥1.3%, the tensile yield strength at 850℃ is ≥340 MPa, and the oxidation weight gain at 850℃ is ≤0.9 mg / cm³. 2 With a service life of ≥130h at 850℃ / 125MPa, it fully meets the requirements of high-temperature service and lightweight design for blades in aero-engines and gas turbines.

[0095] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0096] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a titanium-aluminum alloy blade with an service temperature of 850℃, characterized in that, The preparation method comprises the following steps: Step 1: Preparation of titanium-aluminum alloy powder First, titanium-aluminum alloy powder is prepared using a plasma rotating electrode process. The composition of the titanium-aluminum alloy powder includes: 45-48.5 at.% Al, 1-3 at.% Ta, 1-3 at.% Nb, and 0-0.5 at.% W, with the remainder being Ti and unavoidable impurities. The impurities are controlled to have O ≤ 600 ppm and N ≤ 200 ppm. Then, the titanium-aluminum alloy powder with a particle size of 53 μm to 150 μm is obtained by sieving. Step 2: Packaging and degassing A casing was pre-designed and manufactured according to the specifications of the titanium-aluminum alloy blades. The titanium-aluminum alloy powder obtained from the sieving in step 1 was loaded into the casing. During the powder loading process, vibration was performed while CO gas was introduced, and the casing was kept warm to remove gas. Subsequently, the temperature was maintained and a vacuum was drawn to ≤1×10⁻⁶. -3 Pa; Step 3: Perform staged temperature-controlled hot isostatic pressing on the package after powder filling; Step 4: Remove the cladding by machining to obtain titanium-aluminum alloy blades; In step 2, the flow rate of the introduced CO gas is 50 mL / min to 100 mL / min; during the heat preservation and degassing process, the temperature is set to 600℃ to 700℃ and the time is set to 0.5h to 1.5h. Step 3, the hot isostatic pressing process, is divided into the following three stages: First stage: In the α+γ two-phase region, the temperature is 1250℃~1300℃, the pressure is 110MPa~160MPa, and the temperature is maintained for 2h~5h. Second stage: Heat up to the α single-phase region at 1350℃~1420℃, hold for 15min~40min, and then furnace cool to the α+γ two-phase region at 1250℃~1320℃. The third stage: rapidly cool to 800℃~900℃ at a cooling rate of 15℃ / min~25℃ / min, hold for 3h~5h to relieve stress, and then furnace cool to room temperature.

2. The method for preparing titanium-aluminum alloy blades with an service temperature of 850℃ according to claim 1, characterized in that, In step 1, the titanium-aluminum alloy powder is composed of 46.5–48.3 at.% Al, 1.3–3 at.% Ta, 1–2.8 at.% Nb, and 0.1–0.5 at.% W, with the remainder being Ti and unavoidable impurities.

3. The method for preparing titanium-aluminum alloy blades with an service temperature of 850℃ according to claim 2, characterized in that, In step 1, the impurities in the titanium-aluminum alloy powder are O≤500ppm and N≤150ppm.

4. The method for preparing titanium-aluminum alloy blades with an service temperature of 850℃ according to claim 1, characterized in that, In step 2, the casing material is pure titanium.

5. A titanium-aluminum alloy blade with an service temperature of 850℃, characterized in that, The titanium-aluminum alloy blade is prepared according to the preparation method described in any one of claims 1 to 4.

6. The titanium-aluminum alloy blade with an service temperature of 850°C according to claim 5, characterized in that, The properties of the titanium-aluminum alloy blades are as follows: room temperature tensile elongation ≥1.3%, tensile yield strength at 850℃ ≥340MPa, and oxidation weight gain at 850℃ ≤0.9mg / cm². 2 850℃ / 125MPa creep life ≥130h.

7. An application of the titanium-aluminum alloy blade as described in claim 5 or 6, characterized in that, The titanium-aluminum alloy blades are used in the manufacture of lightweight blades for aero-engines or gas turbines operating in high-temperature environments up to 850°C.

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