Multi-component brazing filler metal for titanium-aluminum alloy brazing and apparatus and method for producing the same

Abstract

This invention relates to the field of brazing materials technology, and particularly to a multi-component brazing filler metal for brazing titanium-aluminum alloys, as well as its preparation apparatus and method. The multi-component brazing filler metal is smelted from Ni, Co, Ti, Zr, and Nb, with the following atomic percentages: Ti 25%~35%, Ni 25%~35%, Nb 10%~20%, Zr 10%~35%, and Co 2%~10%. The preparation method includes steps such as raw material cleaning, weighing, graded smelting, annealing, cutting, and polishing. The brazing filler metal of this invention has a narrow melting range and good fluidity, which can suppress the formation of brittle intermetallic compounds, resulting in high tensile strength of the joint. Furthermore, the preparation process involves low raw material loss and low cost, making it suitable for high-performance brazing of titanium alloys, especially meeting the high-temperature service requirements of titanium alloy connections in aerospace, energy, and chemical industries.

Description

Technical Field

[0001] This invention relates to the field of brazing materials technology, and in particular to a multi-component brazing filler metal for brazing titanium-aluminum alloys, as well as its preparation apparatus and method. Background Technology

[0002] Titanium alloys are widely used in aerospace, energy, and chemical industries due to their excellent properties such as high strength, high toughness, high corrosion resistance, low thermal conductivity, and low density. Brazing, as a common method for joining dissimilar metals, enables high-precision welding of dissimilar materials with minimal deformation. Among various types of brazing filler metals, titanium-based filler metals stand out in titanium alloy brazing because they can achieve joint strength close to that of the base metal. Previous studies have shown that Ti-(Zr)-Cu-Ni amorphous filler metals have been successfully used for brazing various titanium alloys and have demonstrated good joint bonding strength. However, this type of filler metal has a key problem: Ni and Cu, as the main melting point reducing elements, react with Ti during brazing to form lamellar Ti-Cu and Ti-Ni intermetallic compounds. These brittle phases severely affect the service reliability of the joint and limit the improvement of joint strength. Therefore, how to eliminate or reduce brittle intermetallic compounds and change their distribution has become the focus of current research.

[0003] Multi-component alloys, due to the high entropy effect unique to their multi-principal-component configurations, have shown great potential in constructing novel brazing filler metals. This effect helps to suppress the formation of brittle intermetallic compounds and, through the synergistic effect of multiple components, can regulate the microstructure of brazed joints, thereby achieving high-performance connections of titanium alloys. Currently, there are two main methods for preparing this type of brazing filler metal: (1) Amorphous strip brazing filler metal is prepared by melting and strip spinning, but due to the influence of the amorphous forming ability of the filler metal, the width of the filler metal is generally about 5 mm, and it often needs to be spliced ​​for use, making it difficult to guarantee the uniformity of the joint structure; (2) Brazing filler metal foil is prepared by melting and rolling and wire cutting processes, but the filler metal alloy ingots obtained by melting are generally hemispherical, resulting in more losses and higher costs when subsequently processed into filler metal foil.

[0004] See Figure 1 and Figure 2As shown, the existing spherical vacuum arc melting furnace uses a hemispherical melting crucible 104, which is placed on the furnace platform 105. A tipping rod 103 passes through the moving flange 107 and the bellows 106 and is inserted into the furnace cavity 101. The vacuum end of the tipping rod 103 contacts the sample inside the hemispherical melting crucible 104, causing the sample to flip. Contact between the tipping rod 103 and the sample can cause contamination. Because the force applied during operation is applied to the bellows 106, improper operation can affect the service life of the bellows 106. The uneven distance between the coil and the raw material inside the hemispherical melting crucible 104 within the furnace platform 105 leads to uneven magnetic field lines and stirring eddies. Furthermore, the uneven distance between the water-cooled pipes within the furnace platform 105 and the hemispherical melting crucible 104 results in an uneven cooling temperature field. The resulting alloy ingot is hemispherical, leading to significant losses and high costs during subsequent processing into foil. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a multi-component brazing filler metal for brazing titanium-aluminum alloys, as well as its preparation apparatus and method, to obtain a multi-component brazing filler metal with stable composition, excellent performance, and low preparation cost.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a multi-component brazing filler metal for brazing titanium-aluminum alloys, which is smelted from Ni, Co, Ti, Zr and Nb, and the atomic percentage of each component is as follows:

[0008] The composition of Ti is 25%~35%, Ni is 25%~35%, Nb is 10%~20%, Zr is 10%~35%, and Co is 2%~10%, with the sum of the atomic percentages of each component being 100%.

[0009] Another aspect of the present invention provides a multi-component brazing filler metal preparation apparatus for brazing titanium-aluminum alloys as described above, comprising a melting furnace cavity and a lower plate, crucible I, crucible II, and a turning mechanism disposed within the melting furnace cavity. Crucible I is a flat-bottomed structure with openings at both ends. Crucible I is placed on the lower plate and is hinged to the lower plate on one side via a hinge shaft. Metal raw materials, including Ni, Co, Ti, Zr, and Nb, are placed inside crucible I. The metal raw materials are melted by an electric arc. Crucible II is used to hold pure titanium blocks. The turning mechanism is disposed on the melting furnace cavity, with its actuating end located within the melting furnace cavity. The turning mechanism drives crucible I to rotate 180 degrees around the hinge shaft, thereby achieving metal melting at both ends of crucible I.

[0010] The inner surface of the crucible I includes a cone surface I and a cone surface II symmetrically arranged along the axial direction. The small diameter ends of the cone surfaces I and II are arranged opposite each other, and the connection between the cone surfaces I and II is transitioned by a rounded corner.

[0011] The crucible I has a split structure, including a semi-rotating disk I and a semi-rotating disk II. Both semi-rotating disk I and semi-rotating disk II are semi-annular structures, and each end is provided with a lug. The two ends of semi-rotating disk I and semi-rotating disk II are joined together, and the corresponding two lugs are connected by screws and nuts. The outer circumference of semi-rotating disk I is provided with a hinge for connecting with the lower disk. The upper and lower ends of the outer circumference of semi-rotating disk II are respectively provided with annular groove I and annular groove II.

[0012] The material turning mechanism includes a directional ball, a turning rod, a hook, a bellows, a moving flange, and a limiting cylinder. The directional ball is installed on the furnace cavity and can rotate in all directions. The turning rod passes through the directional ball, and one end of it, which is placed inside the furnace cavity, is connected to the hook threaded pair. The hook has a vacuum exhaust hole along the axial direction that communicates with the drilled cavity at the lower end of the threaded pair. The hook is used to drive the crucible I to turn over.

[0013] The bellows is placed outside the directional ball, and both ends of the bellows are connected to the furnace cavity and the moving flange, respectively. The tipping rod passes through the through hole on the moving flange and is sealed by magnetic fluid. The limiting cylinder is set inside the bellows, and one end is connected to the furnace cavity. The limiting cylinder is used to limit the compression stroke of the bellows.

[0014] The lower plate is equipped with an electromagnetic stirring coil and a water cooling pipe.

[0015] Another aspect of the present invention provides a method for preparing multi-component solder using the preparation apparatus described above, characterized by comprising the following steps:

[0016] Step 1: Clean and dry the raw materials of Ni, Co, Ti, Zr and Nb respectively;

[0017] Step 2: Weigh each component according to its atomic percentage:

[0018] The composition of Ti is 25%~35%, Ni is 25%~35%, Nb is 10%~20%, Zr is 10%~35%, and Co is 2%~10%, with the sum of the atomic percentages of all the above components being 100%.

[0019] Step 3: In order of increasing melting point, Ni, Co, Ti, Zr and Nb components are placed into crucible I in the melting furnace cavity. Crucible I has a flat bottom structure with openings at both ends. Pure titanium blocks are placed in crucible II in the melting furnace cavity.

[0020] Step 4: Evacuate the furnace cavity and then fill it with high-purity argon gas.

[0021] Step 5: Use the pure titanium block in the arc melting crucible II, and then use the multi-component raw materials in the arc melting crucible I to obtain a multi-component brazing alloy ingot;

[0022] Step 6: Anneal the multi-component brazing alloy ingot in a vacuum heat treatment furnace;

[0023] Step 7: Cut the annealed multi-component brazing alloy ingot into sheets to make brazing foil with a thickness of 100~200μm.

[0024] In step 1, each of the component raw materials is placed in a 99.7% anhydrous ethanol solution, ultrasonically cleaned using an ultrasonic cleaner, and then dried using a vacuum drying oven.

[0025] In step 5, crucible II is subjected to arc melting using a current of 100A for 60 seconds; crucible I is subjected to multiple arc meltings using a current of 80A-240A, and crucible I is flipped over after each melting and solidification to ensure uniform melting.

[0026] In step 6, the multi-component brazing alloy ingot is annealed in a vacuum heat treatment furnace for 4 to 8 hours; in step 7, the multi-component brazing alloy ingot is cut into pieces and ground and polished using an electrical discharge wire cutting machine.

[0027] The advantages and positive effects of this invention are as follows:

[0028] Excellent brazing alloy performance: The multi-component alloy brazing alloy of this invention has a narrow melting range, good fluidity, and can fully fill the brazing seam; the high mixing entropy effect can effectively suppress the formation of brittle intermetallic compounds in the connection area between titanium alloy and brazing alloy, while the Nb element promotes the brazing seam microstructure to be dominated by the β phase, significantly improving the joint strength. According to the test, the tensile strength of the joint can reach 467-510MPa, which is much higher than that of conventional Ti-based brazing alloys (246-312MPa).

[0029] Excellent high-temperature service performance: The melting point of the brazing filler metal is significantly higher than that of commonly used Ag-based, Al-based and Ti-Cu-based brazing filler metals, which can meet the service requirements of titanium alloys in high-temperature environments and expand their application scenarios.

[0030] The preparation process is pollution-free: Through a specially designed flipping mechanism, the stirring rod and the multi-component alloy brazing filler metal are made into non-contact or non-thermal contact, which avoids pollution caused by contact during the melting process and ensures the purity of the brazing filler metal composition.

[0031] High raw material utilization: The alloy ingots obtained from smelting are round (which can be expanded into square, pentagonal, etc.), resulting in less loss when cutting and processing them into foils, which greatly reduces the preparation cost and solves the problem of high processing loss of traditional hemispherical alloy ingots.

[0032] The process is stable and reliable: the preparation steps are clear, the parameters are controllable, mass production can be achieved, and the brazing filler metal has a stable structure and good repeatability, making it suitable for industrial applications.

[0033] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 A three-dimensional schematic diagram of an existing spherical vacuum arc melting furnace;

[0037] Figure 2 A front view of an existing spherical vacuum arc melting furnace;

[0038] Figure 3 This is an isometric view of an apparatus for preparing multi-component brazing filler metal for brazing titanium-aluminum alloys according to an embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram showing the connection between crucible I and the lower plate in one embodiment of the present invention;

[0040] Figure 5 for Figure 4 Enlarged view of a portion of point A in the middle;

[0041] Figure 6 This is a cross-sectional view of an apparatus for preparing multi-component brazing filler metal for brazing titanium-aluminum alloys according to an embodiment of the present invention.

[0042] Figure 7 for Figure 6 Enlarged view of a section at point B in the middle;

[0043] Figure 8 This is a partial cross-sectional view of the material turning mechanism in one embodiment of the present invention.

[0044] In the diagram: 101. Melting furnace cavity; 102. Directional ball; 103. Tilting rod; 104. Hemispherical melting crucible; 105. Furnace platform; 106. Bellows; 107. Moving flange; 108. Limiting cylinder; 201. First component raw material; 202. Second component raw material; 203. Third component raw material; 204. Fourth component raw material; 205. Fifth component raw material; 3. Lower plate; 301. Electromagnetic stirring coil; 302. 1. Water-cooled pipe; 4. Semi-tilting plate I; 5. Semi-tilting plate II; 501. Conical surface I; 502. Rounded corner; 503. Conical surface II; 504. Tilting plate end face I; 505. Tilting plate end face II; 506. Annular groove I; 507. Annular groove II; 408. Hinge; 6. Hook; 601. Vacuum exhaust port; 602. Threaded pair; 7. Multi-component brazing alloy ingot; 8. Ear seat; 9. Screw; 10. Nut; 11. Crucible I. Detailed Implementation

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0047] One embodiment of the present invention provides a multi-component brazing filler metal for brazing titanium-aluminum alloys, which is smelted from Ni, Co, Ti, Zr and Nb, and the atomic percentage of each component is as follows:

[0048] The composition of Ti is 25%~35%, Ni is 25%~35%, Nb is 10%~20%, Zr is 10%~35%, and Co is 2%~10%, with the sum of the atomic percentages of each component being 100%.

[0049] Specifically, the functions of each component are as follows:

[0050] Ti: As the matrix element of the solder, it ensures the compatibility between the solder and the titanium alloy base material;

[0051] Ni: lowers the melting point of the solder, improves its fluidity, and participates in the formation of a stable alloy phase;

[0052] Nb: As a β stabilizer in titanium alloys, it promotes the β phase as the main phase in the brazed seam microstructure, thereby improving the toughness and strength of the joint.

[0053] Zr: Optimizes the melting range of the brazing filler metal and enhances the metallurgical bond between the filler metal and the base metal;

[0054] Co: It works synergistically with other elements to exert a high-entropy effect, inhibiting the formation of brittle intermetallic compounds and improving the high-temperature stability of the joint.

[0055] The present invention provides a multi-component brazing filler metal for brazing titanium-aluminum alloys, which is suitable for brazing titanium alloys, has good fluidity, stable microstructure and composition, few brittle intermetallic compounds in the weld joint, excellent performance and low manufacturing cost.

[0056] See Figures 3 to 6 As shown, another embodiment of the present invention provides a multi-component brazing filler metal preparation device for brazing titanium-aluminum alloys as described above, including a melting furnace cavity 101 and a lower plate 3, crucible I 11, crucible II, and a turning mechanism disposed within the melting furnace cavity 101. Crucible I 11 is a flat-bottomed structure with openings at both ends. Crucible I 11 is placed on the lower plate 3 and is hinged to the lower plate 3 on one side via a hinge shaft. Metal raw materials, including Ni, Co, Ti, Zr, and Nb, are placed inside crucible I 11. The metal raw materials are melted by an electric arc. Crucible II is used to place pure titanium blocks to remove residual oxygen in the high vacuum environment. The turning mechanism is disposed on the melting furnace cavity 101, with its execution end placed inside the melting furnace cavity 101. The turning mechanism drives crucible I 11 to rotate 180 degrees around the hinge shaft, realizing metal melting at both ends of crucible I 11.

[0057] See Figure 5 and Figure 6 As shown in the embodiment of the present invention, the inner surface of crucible I11 includes conical surfaces I501 and II503 symmetrically arranged along the axial direction. The smaller diameter ends of conical surfaces I501 and II503 are arranged opposite to each other, and the connection between conical surfaces I501 and II503 is transitioned by a fillet 502. During the inversion process of crucible I11, the symmetrically arranged conical surfaces I501 and II503 can effectively fix the solidified disc-shaped multi-component brazing alloy ingot 7, preventing it from falling off.

[0058] Specifically, crucible I11 has a split structure, including a semi-rotating disk I4 and a semi-rotating disk II5. Both semi-rotating disks I4 and II5 are semi-annular structures, and each has a lug 8 at both ends. The two ends of semi-rotating disks I4 and II5 are joined together, and the corresponding lugs 8 are connected by screws 9 and nuts 10. Screws 9 and nuts 10 are made of alumina ceramic. The outer circumference of semi-rotating disk I4 is provided with hinges 408 for connecting with the lower plate 3. The rotating disk end faces I504 and II505 at both ends of crucible I11 are flat and can fit against the upper surface of the lower plate 3.

[0059] Furthermore, the upper and lower ends of the outer circumference of the semi-turning disc II5 are respectively provided with annular groove I506 and annular groove II507, which facilitates the turning mechanism to drive the turning.

[0060] Furthermore, the crucible I11 is made of graphite. During the flipping process, the multi-component brazing alloy ingot 7 is in partial contact with the semi-flipping disk I4 and the semi-flipping disk II5. Because the expansion coefficients of graphite and multi-component brazing alloy ingot 7 are different, adhesion and loss are reduced.

[0061] In an embodiment of the present invention, the material-turning mechanism includes a directional ball 102, a material-turning rod 103, a hook 6, a bellows 106, a moving flange 107, and a limiting cylinder 108. The directional ball 102 is mounted on the melting furnace cavity 101 to form a ball hinge, which can rotate in all directions. The material-turning rod 103 passes through the directional ball 102, and the material-turning rod 103 and the directional ball 102 form a cylindrical pair. The bellows 106 is placed outside the directional ball 102, and both ends of the bellows 106 are respectively connected to the melting furnace cavity 101 and the moving flange 107. The material-turning rod 103 passes through the through hole on the moving flange 107 and can extend and retract relative to the moving flange 107. The material-turning rod 103 and the moving flange 107 are sealed by a magnetohydrodynamic seal to form a cylindrical pair seal. A limiting cylinder 108 is disposed inside the bellows 106, with one end connected to the furnace cavity 101. The limiting cylinder 108 limits the compression stroke of the bellows 106, ensuring that the bellows 106 operates within a controllable range of motion. It has a foolproof function and a longer service life. Compared to fluororubber sealing rings, the magnetohydrodynamic seal has a longer service life. The tilting rod 103 has four degrees of freedom. One end of the tilting rod 103, located inside the furnace cavity 101, is connected to the threaded pair 602 of the hook 6. The hook 6 has a vacuum exhaust port 601 along its axial direction, communicating with the drilled cavity at the lower end of the threaded pair 602. The vacuum exhaust port 601 effectively establishes a high vacuum. The hook 6 is used to drive the crucible I11 to tilt at the annular groove I 506 or annular groove II 507. During the tilting process, the hook 6 does not come into contact with the multi-component alloy brazing filler metal, avoiding contamination.

[0062] In the embodiments of the present invention, the lower plate 3 is provided with an electromagnetic stirring coil 301 and a water cooling pipe 302. Because the crucible I11 has a flat bottom structure, the electromagnetic stirring and water cooling are highly uniform, resulting in good electromagnetic stirring and temperature control effects. Furthermore, because the electromagnetic stirring and water cooling paths are short, energy consumption is reduced and emissions are minimized.

[0063] Another embodiment of the present invention provides a multi-component brazing filler metal preparation device for brazing titanium-aluminum alloys as described above. The device achieves efficient and pollution-free melting of alloy ingots by turning the material in a vacuum arc melting furnace without pollution, and obtains a multi-component brazing filler metal alloy ingot 7 in the form of a disc, which can also be extended to square, pentagonal, etc.

[0064] Another embodiment of the present invention provides a method for preparing a multi-component brazing filler metal for brazing titanium-aluminum alloys as described above, comprising the following steps:

[0065] Step 1: Clean and dry the raw materials of Ni, Co, Ti, Zr and Nb respectively;

[0066] Specifically, the high-purity metal raw materials are placed in a 99.7% anhydrous ethanol solution, ultrasonically cleaned using an ultrasonic cleaner, and then dried using a vacuum drying oven to avoid moisture affecting the smelting effect.

[0067] Step 2: Using an electronic balance with an accuracy of 0.001g, weigh the following raw materials (purity ≥ 99.99wt%) according to atomic percentage:

[0068] The alloy composition consists of 25%~35% Ti, 25%~35% Ni, 10%~20% Nb, 10%~35% Zr, and 2%~10% Co, with the sum of the atomic percentages of each component being 100%, ensuring the precision of the solder composition.

[0069] Step 3: Following the order of melting point from low to high, Ni, Co, Ti, Zr, and Nb component raw materials are sequentially placed into crucible I11 of the melting furnace cavity 101, forming the first component raw material 201, the second component raw material 202, the third component raw material 203, the fourth component raw material 204, and the fifth component raw material 205 from bottom to top, to avoid premature melting of low-melting-point raw materials leading to component segregation; crucible I11 has a flat-bottomed structure with openings at both ends; pure titanium blocks are placed in crucible II of the melting furnace cavity 101 to remove residual oxygen in the furnace by utilizing the strong oxygen absorption property of titanium;

[0070] Step 4: Evacuate the melting furnace cavity 101 to 4×10 -3 Below Pa, high-purity argon gas is then introduced into the melting furnace cavity 101, with the gas pressure controlled at 0.5-0.8 MPa;

[0071] Step 5: Use an electric arc to melt the pure titanium block in crucible II to remove residual oxygen in the high vacuum environment; then use an electric arc to melt the multi-component raw material sample in crucible I11 to obtain a multi-component brazing alloy ingot 7.

[0072] Specifically, crucible II was subjected to arc melting using a current of 100A for 60 seconds; crucible I11 was subjected to multiple arc meltings using a current of 80A-240A, and crucible I11 was flipped over after each melting and solidification to ensure uniform melting; specifically, each sample was melted at least 6 times.

[0073] Step 6: Anneal the multi-component brazing alloy ingot 7 in a vacuum heat treatment furnace for 4-8 hours to eliminate melting stress and stabilize the microstructure;

[0074] Step 7: Cut the annealed multi-component brazing alloy ingot 7 into sheets to make brazing foil sheets with a thickness of 100~200μm; specifically, use an electric discharge wire cutter to cut the multi-component brazing alloy ingot 7 into sheets and grind and polish them.

[0075] The multi-component alloy brazing filler metal obtained in this invention was used for vacuum brazing of Ti2AlNb alloy. The tensile strength was tested according to the test method for brazed joints in GB / T 11363-2008. The results are shown in Table 1.

[0076] Table 1:

[0077]

[0078] Vacuum brazing was performed using conventional titanium-based brazing filler metal, and the tests were conducted according to the same standards. The test results are shown in Table 2.

[0079] Table 2:

[0080]

[0081] As can be seen from the above embodiments and comparative examples, the multi-component brazing filler metal of the present invention exhibits superior joint strength in titanium alloy brazing, and the preparation process has low loss and no pollution, showing significant technical advantages and application prospects.

[0082] The preparation method provided in another embodiment of the present invention yields a multi-component brazing filler metal for titanium-aluminum alloy brazing, which has a narrow melting range and good fluidity. The high mixing entropy of the multi-component alloy brazing filler metal effectively improves the metallurgical reaction at the joint interface and inhibits the formation of brittle intermetallic compounds in the connection area between the titanium alloy and the filler metal. Nb in the multi-component alloy brazing filler metal acts as a β-stabilizer in the titanium alloy, and the microstructure of the weld seam is dominated by the β phase, promoting good joint performance. The melting point of the multi-component alloy brazing filler metal is significantly higher than that of commonly used Ag-based, Al-based, and Ti-Cu-based brazing filler metals, effectively improving the high-temperature service performance of titanium alloy brazed joints. The preparation method of the multi-component alloy brazing filler metal effectively avoids contamination caused by contact with the agitator during the filler metal melting process, and can fully utilize the obtained filler metal alloy ingot, greatly saving costs.

[0083] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A multi-component brazing filler metal for brazing titanium-aluminum alloys, characterized in that, It is smelted from Ni, Co, Ti, Zr and Nb, and the atomic percentage of each component is as follows: The composition of Ti is 25%~35%, Ni is 25%~35%, Nb is 10%~20%, Zr is 10%~35%, and Co is 2%~10%, with the sum of the atomic percentages of each component being 100%.

2. The multi-component brazing filler metal for brazing titanium-aluminum alloys according to claim 1, characterized in that, The brazing filler metal is prepared by a preparation device, which includes a melting furnace cavity and a lower plate, crucible I, crucible II and a material turning mechanism disposed in the melting furnace cavity. Crucible I is a flat-bottomed structure with open top and bottom ends. Crucible I is placed on the lower plate and is hinged to the lower plate on one side by a hinge shaft. Metal raw materials containing Ni, Co, Ti, Zr and Nb are placed in crucible I. The metal raw materials are melted by an electric arc. Crucible II is used to hold pure titanium blocks; the turning mechanism is set on the melting furnace cavity, and the execution end is placed inside the melting furnace cavity. The turning mechanism is used to drive crucible I to rotate 180 degrees around the hinge axis to realize metal melting on both ends of crucible I.

3. The multi-component brazing filler metal for brazing titanium-aluminum alloys according to claim 2, characterized in that, The inner surface of the crucible I includes a cone surface I and a cone surface II symmetrically arranged along the axial direction. The small diameter ends of the cone surfaces I and II are arranged opposite each other, and the connection between the cone surfaces I and II is transitioned by a rounded corner.

4. The multi-component brazing filler metal for brazing titanium-aluminum alloys according to claim 3, characterized in that, The crucible I has a split structure, including a semi-rotating disk I and a semi-rotating disk II. Both semi-rotating disk I and semi-rotating disk II are semi-annular structures, and each end is provided with a lug. The two ends of semi-rotating disk I and semi-rotating disk II are joined together, and the corresponding two lugs are connected by screws and nuts. The outer circumference of semi-rotating disk I is provided with a hinge for connecting with the lower disk. The upper and lower ends of the outer circumference of semi-rotating disk II are respectively provided with annular groove I and annular groove II.

5. The multi-component brazing filler metal for brazing titanium-aluminum alloys according to claim 2, characterized in that, The material turning mechanism includes a directional ball, a turning rod, a hook, a bellows, a moving flange, and a limiting cylinder. The directional ball is installed on the furnace cavity and can rotate in all directions. The turning rod passes through the directional ball, and one end of it, which is placed inside the furnace cavity, is connected to the hook threaded pair. The hook has a vacuum exhaust hole along the axial direction that communicates with the drilled cavity at the lower end of the threaded pair. The hook is used to drive the crucible I to turn over. The bellows is placed outside the directional ball, and both ends of the bellows are connected to the furnace cavity and the moving flange, respectively. The tipping rod passes through the through hole on the moving flange and is sealed by magnetic fluid. The limiting cylinder is set inside the bellows, and one end is connected to the furnace cavity. The limiting cylinder is used to limit the compression stroke of the bellows.

6. The multi-component brazing filler metal for brazing titanium-aluminum alloys according to claim 2, characterized in that, The lower plate is equipped with an electromagnetic stirring coil and a water cooling pipe.

7. A method for preparing a multi-component brazing filler metal for brazing titanium-aluminum alloys as described in any one of claims 2-6, characterized in that, Includes the following steps: Step 1: Clean and dry the raw materials of Ni, Co, Ti, Zr and Nb respectively; Step 2: Weigh each component according to its atomic percentage: The composition of Ti is 25%~35%, Ni is 25%~35%, Nb is 10%~20%, Zr is 10%~35%, and Co is 2%~10%, with the sum of the atomic percentages of all the above components being 100%. Step 3: In order of increasing melting point, Ni, Co, Ti, Zr and Nb components are placed into crucible I in the melting furnace cavity. Crucible I has a flat bottom structure with openings at both ends. Pure titanium blocks are placed in crucible II in the melting furnace cavity. Step 4: Evacuate the furnace cavity and then fill it with high-purity argon gas. Step 5: Use the pure titanium block in the arc melting crucible II, and then use the multi-component raw materials in the arc melting crucible I to obtain a multi-component brazing alloy ingot; Step 6: Anneal the multi-component brazing alloy ingot in a vacuum heat treatment furnace; Step 7: Cut the annealed multi-component brazing alloy ingot into sheets to make brazing foil with a thickness of 100~200μm.

8. The preparation method according to claim 7, characterized in that, In step 1, each of the component raw materials is placed in a 99.7% anhydrous ethanol solution, ultrasonically cleaned using an ultrasonic cleaner, and then dried using a vacuum drying oven.

9. The preparation method according to claim 7, characterized in that, In step 5, crucible II is subjected to arc melting using a current of 100A for 60 seconds; crucible I is subjected to multiple arc meltings using a current of 80A-240A, and crucible I is flipped over after each melting and solidification to ensure uniform melting.

10. The preparation method according to claim 7, characterized in that, In step 6, the multi-component brazing alloy ingot is annealed in a vacuum heat treatment furnace for 4 to 8 hours; in step 7, the multi-component brazing alloy ingot is cut into pieces and ground and polished using an electrical discharge wire cutting machine.

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