Titanium-aluminum alloy blade non-vacuum isothermal forging method and application

Abstract

The invention relates to the technical field of thermoplastic forming of titanium-aluminum intermetallic compounds, in particular to a non-vacuum isothermal forging method for a titanium-aluminum alloy blade and application of the non-vacuum isothermal forging method for the titanium-aluminum alloy blade. By adjusting and controlling the included angle between the extrusion direction of a titanium-aluminum alloy extrusion state raw material and a titanium-aluminum alloy blade blank, screening proper deformation texture orientation and combining specific forging forming parameters, the structure state of a forge piece is guaranteed, and the purpose of reducing the thermoplastic forming resistance of the gamma-type titanium-aluminum alloy is achieved. The titanium-aluminum alloy blade is subjected to non-vacuum isothermal forging forming through the method, the deformation resistance during alloy forming can be effectively reduced, die abrasion is reduced, the die material selection range is widened, a non-vacuum isothermal forging window is provided, and compared with traditional vacuum isothermal forging forming, the manufacturing cost of the blade is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoplastic forming of titanium-aluminum intermetallic compound components, and specifically to a non-vacuum isothermal forging method and application of a titanium-aluminum alloy blade, in particular to a non-vacuum isothermal forging method and application of a titanium-aluminum alloy blade for an aero-engine. Background Art

[0002] Titanium Aluminum Alloy is an intermetallic compound alloy with titanium (Ti) and aluminum (Al) as the main components and formed by adding other alloying elements. It has low density, high specific strength, high specific modulus, and excellent high temperature resistance, oxidation resistance and creep resistance. It has broad application prospects in aerospace, automotive industry, energy and power and other fields.

[0003] In aircraft engines, titanium aluminum alloy blades (density: 3.7-3.9 g / cm 3 ) Replace nickel-based high-temperature alloy blades (density: 7.9 ~ 9.5g / cm 3 ) is expected to achieve a 20% to 30% reduction in engine weight, which can effectively improve the overall performance of the engine. At present, titanium aluminum alloys in aero engines are mainly used in compressor blades, low-pressure turbine blades, fuel nozzles and other parts. Among them, the preparation of compressor blades mainly adopts thermoplastic forming process. Although thermoplastic forming has the advantages of eliminating casting defects, improving alloy microstructure uniformity, and environmental protection and high efficiency, for titanium aluminum alloys with obvious intrinsic brittleness, thermoplastic forming still faces many problems, such as: high deformation temperature, poor high-temperature plasticity, easy to occur local rheology, slow recrystallization dynamics, high temperature deformation resistance, etc. These problems seriously hinder the engineering application of titanium aluminum alloys in the field of aero engines. Among them, the large high-temperature deformation resistance makes the mold material selection less during the isothermal forging of titanium aluminum alloy blades, and some high-temperature and high-strength molds can only be used in a vacuum state, which not only aggravates the mold wear during isothermal forging, but also increases the application difficulty of titanium aluminum alloy blades in non-vacuum forging, resulting in the application difficulties of complex process flow and high manufacturing cost of traditional vacuum isothermal forging. Summary of the invention

[0004] In view of the problem in the prior art that titanium-aluminum alloy blades are difficult to forge under non-vacuum conditions due to large high-temperature deformation resistance during forging, the present invention provides a titanium-aluminum alloy blade non-vacuum isothermal forging method and application.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a non-vacuum isothermal forging method for a titanium-aluminum alloy blade, comprising:

[0007] Prepare a titanium aluminide blade blank; during the preparation of the titanium aluminide blade blank, the original titanium aluminide is prepared by the method of canned hot extrusion. During the preparation of the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original titanium aluminide is controlled to be 80° - 100°.

[0008] Isothermally forge the titanium aluminide blade blank in non-vacuum to obtain a titanium aluminide blade forging; during non-vacuum isothermal forging, the angle between the loading direction and the theoretical parting surface of the titanium aluminide blade blank is 85° - 95°.

[0009] Perform stabilization heat treatment on the titanium aluminide blade forging to obtain a titanium aluminide blade.

[0010] Optionally, the method for preparing the titanium aluminide blade blank is as follows:

[0011] Cut the blade blank from the original titanium aluminide formed by canned hot extrusion in sequence with the angle between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original titanium aluminide being 80° - 100°, and then perform rough machining of the blank, surface sandblasting treatment and spraying of forging lubricant treatment in sequence to obtain the titanium aluminide blade blank.

[0012] Optionally, in the original titanium aluminide formed by canned hot extrusion, the α-phase and α2-phase in the deformed structure present a {0001}<10-10> texture, and the γ lamella presents a {110}<001> texture.

[0013] Optionally, the method for isothermally forging the titanium aluminide blade blank in non-vacuum to obtain a titanium aluminide blade forging is as follows:

[0014] Heat and hold the titanium aluminide blade blank.

[0015] After the holding is completed, isothermally forge the titanium aluminide blade blank in non-vacuum and air-cool it to room temperature to obtain a preform forging of the titanium aluminide blade.

[0016] Cut off the excess flash from the preform forging of the titanium aluminide blade and perform surface sandblasting treatment to obtain the titanium aluminide blade forging.

[0017] Optionally, the heating temperature for heating and holding the titanium aluminide blade blank is 1120°C - 1250°C, and the holding time is 30 - 60 min.

[0018] Optionally, the interval time from the end of holding to the non-vacuum isothermal forging of the titanium aluminide blade blank is ≤15 s.

[0019] Optionally, the conditions for the non-vacuum isothermal forging are as follows: the forging temperature is 1120°C to 1250°C, the pressing speed is 0.05 to 0.2 mm / s, the comprehensive deformation ratio is 0.55 to 0.74, and the pressure holding time is 60 to 90 s.

[0020] Optionally, the temperature for the stabilization heat treatment is 800°C to 950°C, and the treatment time is 12 to 16 h.

[0021] Optionally, by mass percentage, the original titanium aluminide alloy comprises 26% to 35% of Al, 4.2% to 12.2% of Nb, 1.3% to 3.3% of Cr, and ≤2% of Ta, with the balance being Ti and ≤0.6% of impurity elements.

[0022] The present invention provides a titanium aluminide alloy blade, which is prepared by using the above non-vacuum isothermal forging method for titanium aluminide alloy blades.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] A non-vacuum isothermal forging method for a titanium-aluminum alloy blade. This method involves preparing a titanium-aluminum alloy blade blank. During the preparation of the titanium-aluminum alloy blade blank, the original titanium-aluminum alloy is formed by means of enclosed hot extrusion. During the preparation of the titanium-aluminum alloy blade blank, the angle between the theoretical parting surface of the titanium-aluminum alloy blade blank and the extrusion direction of the original titanium-aluminum alloy is controlled to be 80° - 100°. The enclosure can provide certain restraint and protection for the titanium-aluminum alloy, reducing the direct friction and contact between the titanium-aluminum alloy and the die during extrusion, reducing die wear, and at the same time helping to control the deformation flow of the titanium-aluminum alloy during extrusion, making the shape and size of the blank more precise and providing good initial conditions for subsequent forging. Then, the titanium-aluminum alloy blade blank is subjected to non-vacuum isothermal forging to obtain a titanium-aluminum alloy blade forging. During non-vacuum isothermal forging, the angle between the loading direction and the theoretical parting surface of the titanium-aluminum alloy blade blank is 85° - 95°. By coordinately regulating the angle between the extrusion direction of the titanium-aluminum alloy extruded raw material and the titanium-aluminum alloy blade blank, screening suitable deformation texture orientations, and combining specific forging parameters, the tissue state of the forging is ensured, achieving the purpose of reducing the hot plastic forming resistance of the γ-type titanium-aluminum alloy. At the same time, by controlling the forging direction during non-vacuum isothermal forging, not only can the microstructure of the titanium-aluminum alloy be optimized, making its grains finer and more uniform, effectively reducing the influence of the deformation resistance, but also the deformation during forging is more uniform and coordinated, avoiding internal stress concentration and uneven deformation in the material caused by excessive differences in the stress direction, and reducing the generation of forging defects (such as cracks, folds, etc.). Finally, the titanium-aluminum alloy blade forging is subjected to stabilization heat treatment to obtain a titanium-aluminum alloy blade. Stabilization heat treatment can eliminate the residual stress generated during forging, stabilize the tissue structure of the blade, and coordinately with the special forging direction, effectively control the forging tissue to be a duplex tissue, further reducing the plastic deformation resistance of the titanium alloy blade, reducing die wear, expanding the range of die material selection, realizing non-vacuum isothermal forging of the titanium-aluminum alloy blade, and greatly reducing the manufacturing cost.

[0025] The method for preparing the titanium aluminide blade blank is to cut the blade blank from the original aluminum-titanium alloy successively at an angle of 80°-100° between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original aluminum-titanium alloy, and then carry out rough machining of the blank, surface sandblasting treatment and spraying of forging lubricant treatment successively to obtain the titanium aluminide blade blank. Among them, the jacket provides good restraint and protection for the original aluminum-titanium alloy, making its deformation more uniform and stable during the extrusion process, effectively controlling the flow of the material, reducing the dimensional deviation and shape distortion caused by non-uniform deformation of the material, greatly improving the shape and dimensional accuracy of the blank, and providing a more accurate basis for subsequent processing; cutting the blade blank and rough machining in a specific direction can further precisely adjust the shape and size of the blank, remove the surface defects and surplus that may occur during the extrusion process, ensure that the blank meets the design requirements, and improve the qualification rate of the blank; through sandblasting treatment, the scale, impurities and burrs on the surface of the blank can be removed, making the surface smoother and cleaner, which is not only beneficial to the adhesion of the subsequent surface coating, but also can reduce the stress concentration and fatigue damage caused by surface defects during the processing and use of the blank, and improve the reliability and service life of the blank; spraying forging lubricant can form a lubricating film between the blade blank and the die, reduce the friction coefficient of the contact surface, reduce wear, contribute to demoulding and extend the die life, and reduce the maintenance cost.

[0026] In the deformed structure of the original aluminum-titanium alloy formed by hot extrusion of the jacket, the α-phase and α2-phase present the {0001}<10-10> texture, and the γ lamella presents the {110}<001> texture. Among them, the formation of the {0001}<10-10> texture enables the grains to have a highly ordered arrangement in a specific direction, which can effectively hinder the movement of dislocations and enhance the anti-deformation ability of the material. When subjected to external forces, this texture structure makes the material require greater stress to undergo plastic deformation, thus significantly improving the strength of the titanium aluminide blade; the γ lamella is an important strengthening phase in the titanium aluminide alloy, and its {110}<001> texture can optimize the mechanical properties of the lamella, having higher strength and stiffness in a specific direction, and cooperating with the α-phase and α2-phase to further improve the overall strength of the blade, enabling it to withstand greater loads.

[0027] The method for non-vacuum isothermal forging of the titanium aluminide blade blank to obtain a titanium aluminide blade forging is as follows: heat and hold the titanium aluminide blade blank; after the holding is completed, carry out non-vacuum isothermal forging on the titanium aluminide blade blank, air-cool to room temperature, cut off the excess flash and carry out surface sandblasting treatment to obtain a titanium aluminide blade forging. Among them, the process of heating and holding can enable the atoms inside the titanium aluminide blank to obtain sufficient energy for diffusion and rearrangement, significantly refining the grains. The uniformly distributed fine grains can more effectively hinder the movement of dislocations, improving the strength and toughness of the material.

[0028] The temperature for heating and holding the titanium aluminide blade blank is 1120°C to 1250°C, the holding time is 30 to 60 minutes, and the interval time from the end of holding to non-vacuum isothermal forging of the titanium aluminide blade blank is ≤15 s. The heating temperature range of 1120°C to 1250°C covers the α+β two-phase region of the titanium aluminide. Holding at this temperature for 30 to 60 minutes can fully diffuse the internal components of the blank, eliminate segregation and grain boundary defects in the original structure, and provide a uniform microstructure basis for subsequent deformation.

[0029] The conditions for non-vacuum isothermal forging are as follows: the non-vacuum isothermal forging temperature is 1120°C to 1250°C, the pressing speed is 0.05 to 0.2 mm / s, the comprehensive deformation ratio is 0.55 to 0.74, and the pressure holding time is 60 to 90 s. Under these conditions, dynamic recrystallization nuclei can be formed. The high deformation ratio increases the dislocation density, driving the recrystallized grains to be refined to the sub-micron level. At the same time, the coarsening of the β phase is inhibited, forming a mixed structure of equiaxed grains and lath-shaped grains, significantly improving the strength and toughness of the material. The pressure holding time of 60 to 90 s can ensure the full completion of recrystallization, eliminate residual stress, and improve the tissue uniformity, thereby further improving the quality of the forging. The forgings obtained by non-vacuum isothermal forging can not only meet the quality requirements but also effectively reduce the forging cost.

[0030] The temperature of the stabilization heat treatment is 800°C to 950°C, and the treatment time is 12 to 16 h. It can effectively cooperate with non-vacuum isothermal forging to form a duplex structure, further reducing the plastic deformation resistance of the titanium alloy blade and reducing die wear.

[0031] The original titanium aluminide contains 26% to 35% of Al, 4.2% to 12.2% of Nb, 1.3% to 3.3% of Cr, and ≤2% of Ta, with the balance being Ti and ≤0.6% of impurity elements. For this alloy, using the above non-vacuum isothermal forging method, when the deformation amount is about 60%, the deformation resistance is reduced by about 5 to 10 MPa compared to the traditional blanking angle, which is more conducive to realizing the reduction of forging cost in non-vacuum isothermal forging while ensuring the forging quality of the titanium aluminide blade.

[0032] A titanium aluminide blade forged by using the above non-vacuum isothermal forging method for titanium aluminide blades has the characteristics of low production cost, good stability, long die service life, good mechanical properties, and long service life. It realizes multiple goals of performance improvement, cost reduction, and application expansion, and has broad application prospects in the fields of aeroengines, ships, and energy, especially suitable for high-end equipment with demanding material performance requirements. Brief Description of the Drawings

[0033] Figure 1 It is a schematic flow chart of a non-vacuum isothermal forging method for a titanium aluminide blade of the present invention.

[0034] Figure 2 Schematic diagram of the machining cutting angle of the titanium-aluminum alloy blade blank of the present invention.

[0035] Figure 3 Schematic diagram of the included angle between the force direction and the original length direction of the titanium-aluminum alloy during non-vacuum isothermal forging of the present invention;

[0036] Figure 4 Microstructure morphology diagram of the titanium-aluminum alloy blade prepared by a non-vacuum isothermal forging method of the titanium-aluminum alloy blade using the present invention.

[0037] Figure 5 High-temperature deformation stress-strain curve diagram at different included angles between the force direction and the original length direction of the titanium-aluminum alloy during non-vacuum isothermal forging of the present invention. Detailed implementation manners

[0038] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0040] The following further elaborates on the present invention in conjunction with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0041] After analysis, the thermoplastic forming of titanium aluminide requires the deformation temperature to be between the α+γ two-phase regions. The α phase has a hexagonal close-packed (HCP) crystal structure with fewer independent slip systems, and it is prone to form strong deformation textures after deformation. In particular, the γ lamellar structure of titanium aluminide precipitates from the α-phase matrix according to the Blackburn orientation relationship, and the formed lamellar interface is parallel to the basal plane of the α phase [Wang, Y.N., Huang, J.C. Mater Chem Phys. 2003. 81(1): 11-26]. And the orientation of the lamellar interface has an important influence on the high-temperature deformation resistance of the alloy [Umakoshi, Y., Nakano, T. Acta Metall Mater. 1993. 41(4): 1155-1161]. The traditional forging process flow of aero-engine compressor blades is: raw material → preparation of blade blank → blade forging → heat treatment → inspection and warehousing. The original metal material of titanium aluminide is usually prepared by the method of canned hot extrusion. The α-phase orientation in the deformed structure stably flows to the <10-10> and <1-210> orientations in the initial deformation stage, and forms the {0001}<10-10> texture through the {1-210}<10-10> slip in the subsequent deformation. The α phase cools and orderly transforms into the α2 phase, and the corresponding textures are the <10-10> and <1-210> fiber textures, the {1-216}<10-10> and {0001}<10-10> textures in turn. The orientation of the residual γ-phase lamellae satisfies the Blackburn orientation relationship with the orientation of the residual α2-phase lamellae, and the {112}<-1-11> texture, the {111}<-1-12>, the {110}<001> and the {011}<2-11> textures are formed in turn according to the degree of deformation in the subsequent deformation.

[0042] Therefore, this invention patent proposes to utilize the characteristic that the high-temperature deformation resistance of the deformation texture is different in different directions, screen the appropriate deformation texture by controlling the blanking angle during the blank preparation of the metal material, combine specific forging parameters to ensure the tissue state of the forging, and finally achieve the purpose of reducing the thermoplastic forming resistance of γ-type titanium aluminide blades. See Figure 1 , this invention discloses a non-vacuum isothermal forging method for titanium aluminide blades, including:

[0043] S1: Prepare the blank of the titanium aluminide blade, specifically:

[0044] The original titanium aluminide formed by envelope hot extrusion is successively cut into blade blanks at an angle of 80° to 100° between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original titanium aluminide, and then the blank is subjected to finish machining, surface sandblasting treatment and spraying of forging lubricant treatment in sequence to obtain a titanium aluminide blade blank. Preferably, by mass percentage, the original titanium aluminide comprises 26% - 35% of Al, 4.2% - 12.2% of Nb, 1.3% - 3.3% of Cr and ≤2% of Ta, and the balance is Ti and ≤0.6% of impurity elements. Preferably, in the original titanium aluminide formed by envelope hot extrusion, the α phase and α2 phase in the deformed microstructure present {0001}<10-10> texture as much as possible, and the γ lamella presents {110}<001> texture as much as possible. Further preferably, in the deformed microstructure of the envelope hot extrusion forming, the α phase and α2 phase present {0001}<10-10> texture, and the γ lamella presents {110}<001> texture

[0045] S2: The titanium aluminide blade blank is subjected to non-vacuum isothermal forging to obtain a titanium aluminide blade forging; wherein, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 85° - 95°, specifically:

[0046] The titanium aluminide blade blank is heated to 1120°C - 1250°C and held for 30 - 60 min;

[0047] After the holding is completed, the titanium aluminide blade blank is subjected to non-vacuum isothermal forging and air-cooled to room temperature to obtain a titanium aluminide blade pre-forging;

[0048] The excess flash of the titanium aluminide blade pre-forging is removed and the surface is sandblasted to obtain a titanium aluminide blade forging;

[0049] Wherein, the conditions for the non-vacuum isothermal forging are: the non-vacuum isothermal forging temperature is 1120°C - 1250°C, the pressing speed is 0.05 - 0.2 mm / s, the comprehensive deformation ratio is 0.55 - 0.74, the pressure holding time is 60 - 90 s, and the time interval from the end of holding to the transfer to non-vacuum isothermal forging is ≤15 s.

[0050] S3: The titanium aluminide blade forging is subjected to stabilization heat treatment to obtain a titanium aluminide blade, specifically:

[0051] The titanium aluminide blade forging is subjected to stabilization heat treatment at 800°C - 950°C for 12 - 16 h to obtain a titanium aluminide blade.

[0052] A titanium aluminide blade is forged by using the above non-vacuum isothermal forging method for titanium aluminide blades. This titanium aluminide blade has the characteristics of low production cost, good stability, long die service life, good mechanical properties, long service life, etc., achieving multiple goals of performance improvement, cost reduction, and application expansion, and has broad application prospects in the fields of aeroengines, ships, and energy, especially suitable for high-end equipment with demanding material performance requirements.

[0053] Example 1

[0054] Using Ti-48Al-2Nb-2Cr (indicating 48% Al, 2% Nb, and 2% Cr by atomic percentage, with the balance being Ti) titanium aluminide as the raw material, the Ti-48Al-2Nb-2Cr titanium aluminide formed by envelope hot extrusion is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain the titanium aluminide blade blank.

[0055] The titanium aluminide blade blank is placed in a heating furnace and heated to 1200 °C and held for 45 min. After the holding is completed, the titanium aluminide blade blank is transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 7 s. Subsequently, isothermal forging is carried out. The forging temperature is 1200 °C, the pressing speed is 0.1 mm / s, and the comprehensive deformation ratio of the blade body is ensured to be 0.65 through die and blank design. After forging, the pressure holding time is 75 s. After forming and demolding, the forging is air-cooled to room temperature to obtain the titanium aluminide blade forging; see Figure 2 and Figure 3 , where, during the process of preparing the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the original titanium aluminide extrusion direction is controlled to be 90°; during the non-vacuum isothermal forging process, the loading direction during non-vacuum isothermal forging is at an angle of 90° to the theoretical parting surface of the titanium aluminide blade blank.

[0056] The above titanium aluminide blade forging is subjected to stabilization heat treatment at 900 °C for 14 h and cooled to room temperature with the furnace to eliminate the internal residual stress of the forging and stabilize the alloy microstructure, obtaining a titanium aluminide blade with a duplex structure for the alloy blade body.

[0057] See Figure 4 , and for the titanium aluminide blade prepared in this example, morphological and microstructural observations are carried out, and it is found that its surface is intact, without defects such as cracks, porosity, cavities, and folds.

[0058] Example 2

[0059] Using Ti-47Al-2Nb-2Cr-0.15B (by atomic percentage, including 47% Al, 2% Nb, 2% Cr, and 0.15% B, with the balance being Ti) titanium aluminide as the raw material, the Ti-47Al-2Nb-2Cr-0.15B titanium aluminide formed by jacket hot extrusion is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain the titanium aluminide blade blank.

[0060] The titanium aluminide blade blank is placed in a heating furnace and heated to 1120 °C and held for 60 min. After the holding is completed, the titanium aluminide blade blank is transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 6 s. Subsequently, isothermal forging is carried out. The forging temperature is 1120 °C, the pressing speed is 0.05 mm / s. By designing the die and the blank, the comprehensive deformation ratio of the blade body is ensured to be 0.6. After forging, the pressure holding time is 70 s. After forming and demolding, the forging is air-cooled to room temperature to obtain the titanium aluminide blade forging; among them, during the preparation of the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the original titanium aluminide extrusion direction is controlled to be 95°; during the non-vacuum isothermal forging process, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 85°.

[0061] The above-mentioned titanium aluminide blade forging is subjected to stabilization heat treatment at 950 °C for 12 h and cooled to room temperature in the furnace to eliminate the internal residual stress of the forging and stabilize the alloy microstructure, obtaining a titanium aluminide blade with a duplex structure for the alloy blade body.

[0062] Example 3

[0063] Using titanium aluminide with 26% Al, 12.2% Nb, 3.3% Cr, and 1% Ta, with the balance being Ti as the raw material, the titanium aluminide formed by jacket hot extrusion is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain the titanium aluminide blade blank.

[0064] The titanium aluminide blade blank is placed in a heating furnace and heated to 1220 °C and held for 60 min. After the holding is completed, the titanium aluminide blade blank is transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 6 s. Subsequently, isothermal forging is carried out. The forging temperature is 1220 °C, the pressing speed is 0.08 mm / s. By designing the die and the blank, the comprehensive deformation ratio of the blade body is ensured to be 0.55. After forging, the pressure holding time is 60 s. After forming and demolding, the forging is air-cooled to room temperature to obtain the titanium aluminide blade forging; among them, during the preparation of the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the original titanium aluminide extrusion direction is controlled to be 80°; during the non-vacuum isothermal forging process, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 95°.

[0065] The above-mentioned titanium-aluminum alloy blade forgings are subjected to stabilization heat treatment at 850 °C for 14 h, cooled in the furnace to room temperature, the internal residual stress of the forgings is eliminated, and the microstructure of the alloy is stabilized to obtain titanium-aluminum alloy blades with a duplex structure in the blade body.

[0066] Example 4

[0067] Using a titanium-aluminum alloy with 35% Al, 4.2% Nb, 1.3% Cr, and 2% Ta, with the balance being Ti as the raw material, the titanium-aluminum alloy formed by envelope hot extrusion is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain titanium-aluminum alloy blade blanks.

[0068] The titanium-aluminum alloy blade blanks are placed in a heating furnace and heated to 1250 °C and held for 30 min. After the holding is completed, the titanium-aluminum alloy blade blanks are transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 5 s. Subsequently, isothermal forging is carried out. The forging temperature is 1250 °C, the pressing speed is 0.2 mm / s. By designing the die and the blank, the comprehensive deformation ratio of the blade body is ensured to be 0.74. The pressure holding time after forging is 90 s. After forming and demolding, the forgings are air-cooled to room temperature to obtain titanium-aluminum alloy blade forgings; among them, during the preparation of the titanium-aluminum alloy blade blanks, the angle between the theoretical parting surface of the titanium-aluminum alloy blade blanks and the original extrusion direction of the titanium-aluminum alloy is controlled to be 100°; during the non-vacuum isothermal forging process, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium-aluminum alloy blade blanks is 93°.

[0069] The above-mentioned titanium-aluminum alloy blade forgings are subjected to stabilization heat treatment at 800 °C for 16 h, cooled in the furnace to room temperature, the internal residual stress of the forgings is eliminated, and the microstructure of the alloy is stabilized to obtain titanium-aluminum alloy blades with a duplex structure in the blade body.

[0070] Comparative Example 1

[0071] Using Ti-48Al-2Nb-2Cr (indicating 48% Al, 2% Nb, and 2% Cr by atomic percentage, with the balance being Ti) titanium-aluminum alloy as the raw material, the Ti-48Al-2Nb-2Cr titanium-aluminum alloy formed by envelope hot extrusion is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain titanium-aluminum alloy blade blanks.

[0072] The titanium-aluminum alloy blade blanks are placed in a heating furnace and heated to 1200 °C and held for 45 min. After the holding is completed, the titanium-aluminum alloy blade blanks are transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 7 s. Subsequently, isothermal forging is carried out. The forging temperature is 1200 °C, the pressing speed is 0.1 mm / s. By designing the die and the blank, the comprehensive deformation ratio of the blade body is ensured to be 0.65. The pressure holding time after forging is 75 s. After forming and demolding, the forgings are air-cooled to room temperature to obtain titanium-aluminum alloy blade forgings; see Figure 2 andFigure 3 During the preparation of the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the original extrusion direction of the titanium aluminide is controlled at 45°; during non-vacuum isothermal forging, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 90°.

[0073] The above-mentioned titanium aluminide blade forging is subjected to stabilization heat treatment at 900 °C for 14 h, and then cooled to room temperature in the furnace to eliminate the internal residual stress of the forging and stabilize the microstructure of the alloy, obtaining a titanium aluminide blade with a duplex structure in the alloy blade body.

[0074] Comparative Example 2

[0075] Using Ti-48Al-2Nb-2Cr (indicating 48% Al, 2% Nb, and 2% Cr by atomic percentage, with the balance being Ti) titanium aluminide as the raw material, the Ti-48Al-2Nb-2Cr titanium aluminide formed by hot extrusion of the cladding is cut, processed into blanks, sandblasted, and treated with sprayed lubricating glass to obtain a titanium aluminide blade blank.

[0076] The titanium aluminide blade blank is placed in a heating furnace and heated to 1200 °C and held for 45 min. After the holding is completed, the titanium aluminide blade blank is transferred to a non-vacuum isothermal hydraulic press, and the transfer time is about 7 s. Subsequently, isothermal forging is carried out, the forging temperature is 1200 °C, the pressing speed is 0.1 mm / s, the comprehensive deformation ratio of the blade body is ensured to be 0.65 through die and blank design, the holding time after forging is 75 s, and after forming and demolding, the forging is air-cooled to room temperature to obtain a titanium aluminide blade forging; see Figure 2 and Figure 3 During the preparation of the titanium aluminide blade blank, the angle between the theoretical parting surface of the titanium aluminide blade blank and the original extrusion direction of the titanium aluminide is controlled at 0°; during non-vacuum isothermal forging, the angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 90°.

[0077] The above-mentioned titanium aluminide blade forging is subjected to stabilization heat treatment at 900 °C for 14 h, and then cooled to room temperature in the furnace to eliminate the internal residual stress of the forging and stabilize the microstructure of the alloy, obtaining a titanium aluminide blade with a duplex structure in the alloy blade body.

[0078] See Figure 5, to further illustrate the beneficial effects of the present invention, a high-temperature deformation comparison was made between Example 1 of the present invention and Comparative Example 1 and Comparative Example 2. The results showed that when the deformation amount was about 60%, the deformation resistance decreased by about 5-10 MPa compared with the traditional (Comparative Example 2) blanking angle. It can be seen that the present invention can effectively improve the problem of large deformation resistance by adjusting the angle between non-vacuum isothermal forging and the extrusion direction, reduce die wear, expand the range of die material selection, realize non-vacuum isothermal forging of titanium-aluminum alloy blades, and greatly reduce the manufacturing cost.

[0079] The above are only the preferred embodiments of the present invention and are not used to limit the technical solutions of the present invention in any way. Those skilled in the art should understand that without departing from the spirit and principles of the present invention, the technical solutions can be subject to several simple modifications and substitutions, and these modifications and substitutions also fall within the protection scope covered by the claims.

Claims

1. A non-vacuum isothermal forging method for a titanium-aluminum alloy blade, characterized in that, Including: Preparing a titanium aluminide blade blank; wherein, in the process of preparing the titanium aluminide blade blank, an original titanium aluminide is prepared by means of canned hot extrusion. During the process of preparing the titanium aluminide blade blank, the included angle between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original titanium aluminide is controlled to be 80°-100°; Performing non-vacuum isothermal forging on the titanium aluminide blade blank to obtain a titanium aluminide blade forging; wherein, the included angle between the loading direction during non-vacuum isothermal forging and the theoretical parting surface of the titanium aluminide blade blank is 85°-95°; Performing stabilization heat treatment on the titanium aluminide blade forging to obtain a titanium aluminide blade.

2. The non-vacuum isothermal forging method of a titanium-aluminum alloy blade according to claim 1, characterized in that, The method for preparing the titanium aluminide blade blank is as follows: The original titanium aluminide formed by canned hot extrusion is sequentially cut into blade blanks at an included angle of 80°-100° between the theoretical parting surface of the titanium aluminide blade blank and the extrusion direction of the original titanium aluminide, and then rough machining of the blank, surface sandblasting treatment and spraying of forging lubricant treatment are sequentially carried out to obtain a titanium aluminide blade blank.

3. The non-vacuum isothermal forging method of a titanium-aluminum alloy blade according to claim 1, characterized in that In the deformed structure of the original titanium aluminide formed by canned hot extrusion, the α phase and the α2 phase present a {0001}<10-10> texture, and the γ lamella presents a {110}<001> texture.

4. The non-vacuum isothermal forging method of a titanium-aluminum alloy blade according to claim 1, characterized in that, The method for performing non-vacuum isothermal forging on the titanium aluminide blade blank to obtain a titanium aluminide blade forging is as follows: Heating and insulating the titanium aluminide blade blank; After the insulation is completed, performing non-vacuum isothermal forging on the titanium aluminide blade blank and air-cooling it to room temperature to obtain a pre-forged titanium aluminide blade; Cutting off the redundant burrs of the pre-forged titanium aluminide blade and performing surface sandblasting treatment to obtain a titanium aluminide blade forging.

5. The non-vacuum isothermal forging method of a titanium-aluminum alloy blade according to claim 4, characterized in that, The heating temperature for heating and insulating the titanium aluminide blade blank is 1120°C-1250°C, and the insulation time is 30-60 min.

6. The non-vacuum isothermal forging method of a titanium-aluminum alloy blade according to claim 4, characterized in that, The interval time from the end of insulation to the non-vacuum isothermal forging of the titanium aluminide blade blank ≤ 15 s.

7. The non-vacuum isothermal forging method of a titanium aluminum alloy blade according to claim 1, characterized in that, The conditions for the non-vacuum isothermal forging are: the forging temperature is 1120°C-1250°C, the pressing speed is 0.05-0.2 mm / s, the comprehensive deformation ratio is 0.55-0.74, and the pressure holding time is 60-90 s.

8. The non-vacuum isothermal forging method of a titanium aluminum alloy blade according to claim 1, characterized in that, The temperature of the stabilization heat treatment is 800°C-950°C, and the treatment time is 12-16 h.

9. The non-vacuum isothermal forging method for titanium-aluminum alloy blades according to any one of claims 1-8, characterized in that, By mass percentage, the original titanium aluminide includes 26%-35% of Al, 4.2%-12.2% of Nb, 1.3%-3.3% of Cr and ≤ 2% of Ta, and the balance is Ti and ≤ 0.6% of impurity elements.

10. A titanium-aluminum alloy blade, characterized in that, Prepared by using the non-vacuum isothermal forging method of the titanium aluminide blade according to any one of claims 1-9.

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