A nickel-based brazing filler metal containing refractory multi-principal element alloy and a preparation method and application thereof

Abstract

The application discloses a nickel-based brazing filler metal containing refractory multi-principal component alloy and a preparation method and application thereof, and comprises a brazing filler metal base body and a refractory multi-principal component alloy powder, wherein the refractory multi-principal component alloy powder comprises at least two of W, Mo, Ta and Nb, and at least one of V, Ti, Hf, Zr, Cu, Ni and Co or none of V, Ti, Hf, Zr, Cu, Ni and Co; in the refractory multi-principal component alloy powder, the molar ratio of any two elements is 0.95-1.05. By introducing the refractory multi-principal component alloy powder, the melting temperature of the nickel-based brazing filler metal can be reduced, the wettability of the brazing filler metal is good, an intermediate layer composed of the refractory multi-principal component alloy powder and the fusible nickel-based brazing filler metal can be formed between the brazing filler metal and the base material, the compatibility of the two is improved, a stable solid solution or intermetallic compound is formed, the shear strength of the brazing joint is improved, the residual stress level of the joint is significantly reduced, and the overall reliability of the joint is improved.

Description

Technical Field

[0001] This invention relates to the field of nickel-based brazing filler metal technology, and in particular to a nickel-based brazing filler metal containing a refractory multi-principal-element alloy, its preparation method, and its application. Background Technology

[0002] In high-end equipment such as fusion reactor divertors and first walls, combat component heads, and spacecraft leading edges, the structures are usually made of a variety of high-temperature resistant materials such as tungsten-based materials, steel-based materials, and nickel-based high-temperature alloys, and often present complex and precise structures of dual alloys or multiple alloys.

[0003] For the connection requirements of such structures, brazing is a common method used in engineering applications to solve the welding problems of complex and precision bialloy structures. Its basic principle is to heat the base material and the filler metal together to a temperature range higher than the melting point of the filler metal but lower than the melting point of the base material. This causes the filler metal to melt and wet the surface of the base material, while the base material itself remains unmelted, thus achieving a metallurgical connection. Nickel-based filler metals are widely used for joining metallic materials due to their low melting temperature, good wettability, and the good high-temperature strength, excellent oxidation resistance, and corrosion resistance of the brazed joints they form.

[0004] However, in the process of joining dissimilar high-temperature resistant materials, existing nickel-based brazing fillers are difficult to meet the wetting requirements. At the same time, there are problems such as residual stress concentration, insufficient mechanical properties, and easy cracking caused by the large difference in the thermal expansion coefficients between materials at the weld joint. As a result, the reliability and service stability of the joint still face challenges. Summary of the Invention

[0005] The purpose of this invention is to propose a nickel-based brazing filler metal containing a refractory multi-principal-element alloy, its preparation method and application, aiming to solve the problems of insufficient wettability, large residual stress and poor mechanical properties of existing nickel-based brazing filler metals in high-temperature dissimilar material joining.

[0006] The first aspect of this application discloses a nickel-based solder containing a refractory multi-principal alloy, comprising a solder matrix and refractory multi-principal alloy powder, wherein the refractory multi-principal alloy powder comprises: The material contains at least two of W, Mo, Ta, and Nb, and includes at least one of V, Ti, Hf, Zr, Cu, Ni, and Co, or excludes V, Ti, Hf, Zr, Cu, Ni, and Co.

[0007] In one embodiment, the molar ratio between any two elements in the refractory multi-principal alloy powder is 0.95 to 1.05.

[0008] In one embodiment, the nickel-based brazing filler metal contains 5-30% by mass of refractory multi-principal alloy powder.

[0009] In one embodiment, the nickel-based brazing filler metal contains 7-20% by mass of refractory multi-principal alloy powder.

[0010] In one embodiment, the solder matrix comprises, by weight percentage: Cr: 0~12wt%, Si: 1~3wt%, B: 1~3wt%, Fe≤5%, with the balance being Ni.

[0011] In one embodiment, the nickel-based solder has a particle size range of 5 to 60 μm.

[0012] According to a second aspect of this application, a method for preparing a nickel-based brazing filler metal containing a refractory multi-principal alloy is provided, comprising the following steps: S1, weighing the brazing filler metal matrix and the refractory multi-principal alloy powder according to the mass percentage; S2, grinding and mixing the materials weighed in step S1 to obtain a nickel-based brazing filler metal containing the refractory multi-principal alloy.

[0013] According to a third aspect of this application, the application of the nickel-based brazing filler metal containing refractory multi-principal alloys or the nickel-based brazing filler metal containing refractory multi-principal alloys prepared by the above preparation method in dissimilar alloy joining is provided.

[0014] In one embodiment, the connection process involves applying the nickel-based brazing filler metal to the area to be brazed and then performing the brazing connection in a vacuum environment.

[0015] In one embodiment, the brazing temperature of the nickel-based brazing filler metal is 1050~1125℃, and the brazing holding time is 30~180min.

[0016] The embodiments of the present invention have the following beneficial effects: 1. The nickel-based brazing filler metal containing a refractory multi-principal alloy provided by this invention constructs a composite system of "nickel-based brazing filler metal matrix + refractory multi-principal alloy particles" by introducing refractory multi-principal alloy powder into a nickel-based brazing filler metal matrix. Preferably, the refractory multi-principal alloy powder contains at least two high-melting-point, high-modulus elements selected from W, Mo, Ta, and Nb, and may further incorporate elements such as V, Ti, Hf, and Zr for compositional control, thereby forming a synergistic multi-principal alloy structure. During brazing, the refractory multi-principal alloy particles partially dissolve as a dispersed phase and participate in the interfacial reaction. On the one hand, they regulate the formation and distribution of interfacial phases and inhibit the formation of continuous brittle phases; on the other hand, their low thermal expansion characteristics adjust the thermophysical parameters of the brazing seam region, thereby reducing residual stress between dissimilar materials. The nickel-based brazing filler metal matrix provides good liquid wetting and filling capabilities, achieving interfacial metallurgical bonding. The synergistic effect of both effectively improves the interfacial structural stability and joint mechanical properties during the joining of highly dissimilar materials.

[0017] 2. The method for preparing nickel-based brazing filler metal containing refractory multi-principal alloy provided by the present invention is simple and only requires grinding and mixing the nickel-based brazing filler metal matrix and the refractory multi-principal alloy powder. It is easy to operate and implement in engineering.

[0018] 3. The welding method provided by the present invention adopts vacuum brazing. By extending the brazing holding time, the composition of the weld structure can be made more uniform, enabling low-temperature welding and high-temperature service, and effectively avoiding the formation of joint oxides, thereby obtaining a brazed joint with excellent performance and stable structure. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] in: Figure 1 The electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the brazed joint in Example 1 are shown below. Figure 2 The electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the brazed joint in Example 2 are shown below. Figure 3 The electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the brazed joint in Example 3 are shown below. Figure 4 The images show the electron microscope morphology and energy dispersive spectroscopy (EDS) analysis of the nickel-based solder containing refractory multi-principal-element alloy in Example 3. Figure 5 The electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the brazed joint in Example 4 are shown below. Figure 6 The electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the brazed joint in Example 5 are shown below. Figure 7 The image shows the electron microscope morphology and energy dispersive spectroscopy (EDS) analysis of the nickel-based brazed joint in Comparative Example 1. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This application provides a nickel-based solder containing a refractory multi-principal alloy, comprising a solder matrix and refractory multi-principal alloy powder. The refractory multi-principal alloy powder comprises at least two of W, Mo, Ta, and Nb, and includes at least one of V, Ti, Hf, Zr, Cu, Ni, and Co, or excludes V, Ti, Hf, Zr, Cu, Ni, and Co.

[0023] In this embodiment, refractory multi-principal alloy powder is introduced into the nickel-based brazing filler metal. This powder serves as a reinforcing and modifying phase, containing at least two of the four high-melting-point, high-modulus refractory metals W, Mo, Ta, and Nb, or V, Ti, Hf, Zr, Cu, Ni, and Co elements as alloying control elements. This activates the interface and regulates the weld microstructure, thereby suppressing the generation of brittle phases in the brazed joint, eliminating residual stress, and improving the high-temperature performance of the joint. The brazing filler metal matrix acts as a liquid filler, facilitates basic interface bonding, and promotes overall joint formation. The synergistic effect of the brazing filler metal matrix and the refractory multi-principal alloy powder solves the problems of uneven wettability, poor interfacial bonding, high residual stress, unbalanced joint performance, and high-temperature failure in multi-metal welding, thus improving the overall reliability of the brazed joint.

[0024] In the welding of tungsten alloys with other metals, on the one hand, the partial dissolution of refractory multi-principal component powder, accompanied by the movement of the brazing filler metal's solid-liquid interface and the extension and growth of the base metal, not only lowers the melting temperature of the nickel-based brazing filler metal and maintains good wettability, but also forms an intermediate layer between the brazing filler metal and the base metal, composed of refractory multi-principal component alloy powder and fusible nickel-based brazing filler metal. This improves the compatibility between the brazing filler metal and the base metal, thereby forming a stable solid solution or intermetallic compound, thus increasing the shear strength of the brazed joint. On the other hand, refractory multi-principal component alloy powder has a low coefficient of linear expansion, and its introduction can effectively regulate the expansion and contraction of the brazed joint during the cooling process due to the influence of the base metal. The thermal stress generated by the difference in thermal expansion coefficients between the materials significantly reduces the residual stress level of the joint, thereby solving the problem that cracks are easily generated at the joint due to the large difference in thermal expansion coefficients between tungsten alloys and other metals. Thirdly, the refractory multi-principal alloy powder plays an interface regulation role in the brazed joint, affecting the generation and distribution of brittle phases in the joint, forming a core-shell structure around the powder, breaking or blocking the formation path of continuous brittle phases, thereby inhibiting crack initiation and propagation, improving the overall reliability of the joint, and enabling the metal to adapt to extreme thermo-mechanical-environment coupled service conditions after welding, ensuring the mechanical properties and service reliability of the brazed joint.

[0025] In this embodiment, nickel-based brazing filler metals are suitable for high-temperature dissimilar metal materials, especially for joining systems with large differences in thermophysical properties that are prone to interfacial residual stress and brittle reaction layers, including but not limited to: tungsten and tungsten alloys / ODS steel, tungsten and tungsten alloys / steel-based alloys, tungsten and tungsten alloys / nickel-based high-temperature alloys, etc.

[0026] In one embodiment, the molar ratio between any two elements in the refractory multi-principal alloy powder is 0.95 to 1.05.

[0027] The element combination and proportion limitation in refractory multi-principal alloy powder can ensure that the system forms a significant high-entropy effect, thereby achieving effective control over the reaction behavior and microstructure evolution of the brazing interface. If it is a single-element powder or exceeds the limited proportion range, the mixing entropy is insufficient, the system tends to be more like a traditional alloy, its interface reaction path is single, it is easy to form a continuous brittle phase, and it is difficult to adjust the thermal expansion coefficient and other thermophysical parameters through the synergistic effect of multiple components. As a result, the residual stress in the dissimilar material joining process is difficult to be effectively released, thereby reducing the mechanical properties and microstructure stability of the joint.

[0028] In one embodiment, the nickel-based brazing filler metal contains 5-30% by mass percentage of refractory multi-principal alloy powder.

[0029] The shear strength of brazed joints is related to the content of refractory multi-principal alloy powder. An appropriate amount of refractory multi-principal particles can effectively regulate the interfacial reaction and thermophysical property matching, while an excessively high content will reduce the fluidity of the brazing filler metal and cause uneven microstructure, thereby leading to a decline in joint performance.

[0030] In one embodiment, the content of refractory multi-principal alloy powder in the nickel-based brazing filler metal is 7-20% by mass percentage.

[0031] In one embodiment, the solder matrix comprises, by weight percentage: Cr: 0~12wt%, Si: 1~3wt%, B: 1~3wt%, Fe≤5%, with the balance being Ni.

[0032] In this embodiment, limiting the proportions of each element in the nickel-based solder matrix reduces the melting temperature of the nickel-based solder, facilitates interfacial reactions and regulates phase formation, suppresses the formation of continuous brittle phases, and improves interfacial wetting and diffusion behavior, achieving synergistic optimization of joint performance. Ni, as a matrix element, provides good toughness and high-temperature stability; Cr helps improve wettability and participates in interfacial reaction regulation; Si and B significantly reduce the solder melting temperature and promote transient liquid phase formation, thereby improving solder fluidity and filling capacity. If a single element is used as the solder matrix in existing technologies, the lack of a melting point-reducing component results in a high melting point, making it difficult to form a liquid phase at lower temperatures, which is detrimental to interfacial wetting and diffusion bonding. Insufficient interfacial reactions also easily lead to inadequate joint bonding. This embodiment, through the rational design of the Ni-Cr-Si-B system proportions, reduces the brazing temperature while achieving controllable interfacial reactions and optimized thermophysical property matching, significantly improving the strength and reliability of the brazed joint.

[0033] In one embodiment, the particle size range of the nickel-based solder is 5~60μm.

[0034] The particle size of nickel-based brazing filler metals needs to achieve a balance between flowability, reactivity, and interfacial control capability. This embodiment limits the particle size of the nickel-based brazing filler metal to ensure good spreadability and stable interfacial reaction behavior. When the particle size is too small, the specific surface area increases significantly, which can easily lead to rapid or even excessive dissolution of the powder during heating. This makes it difficult for the refractory multi-principal alloy powder to maintain an effective dispersed phase structure, thereby weakening its control over the interfacial reaction path and thermophysical parameters. At the same time, excessively fine powder is also prone to oxidation, agglomeration, and sintering densification, affecting the flowability and uniform filling ability of the brazing filler metal, and may even lead to local component segregation or excessive reaction, promoting the formation of brittle phases. Reasonable limitation of the particle size range can ensure that the composite brazing filler metal can fully participate in the interfacial reaction during brazing while maintaining a stable structural control function, thereby obtaining excellent joint performance.

[0035] This application provides a method for preparing a nickel-based solder containing a refractory multi-principal-element alloy, comprising the following steps: S1. Weigh out the brazing filler metal matrix and refractory multi-principal element alloy powder according to the mass percentage; S2. Grind and mix the material weighed in step S1 to obtain a nickel-based brazing filler metal containing a refractory multi-principal alloy.

[0036] In this embodiment, the preparation method is simple and only requires grinding and mixing the nickel-based solder matrix and the refractory multi-principal-element alloy powder. It is highly operable and easy to implement in engineering.

[0037] Specifically, the grinding process in step S2 is carried out in a ball mill, with a grinding speed of 200~400 rpm and a grinding time of 5~8 hours.

[0038] Specifically, the solder substrate described in this embodiment can be prepared using conventional methods in the art: Ni, Cr, Si, B, and Fe raw materials are weighed according to a predetermined composition ratio. NiCrSiB brazing filler powder is prepared by vacuum induction melting or gas atomization powder preparation. The obtained powder is then sieved to obtain the desired particle size range. Among these methods, using gas atomization to obtain spherical or near-spherical powder can improve powder flowability and spreading ability during brazing.

[0039] Specifically, the refractory multi-principal element alloy powder described in this embodiment can be prepared using conventional methods in the art: Selected elements are weighed according to a predetermined ratio, and refractory multi-principal element alloy powder is prepared by means of vacuum arc melting, mechanical alloying, plasma spheroidization or gas atomization, and the target particle size range is obtained by sieving.

[0040] A combination of mechanical alloying and ball milling was used to achieve uniform mixing of multiple principal elements.

[0041] This application provides the application of the nickel-based brazing filler metal containing refractory multi-principal alloys or the nickel-based brazing filler metal containing refractory multi-principal alloys prepared by the above preparation method in dissimilar alloy joining.

[0042] In one embodiment, the connection process involves applying the nickel-based brazing filler metal to the area to be soldered and then performing brazing in a vacuum environment.

[0043] In this embodiment, the welding method adopts vacuum brazing. By controlling the conditions of vacuum welding, the composition of the weld structure tends to be uniform, which can achieve low-temperature welding and high-temperature service, and effectively avoid the formation of joint oxides, thereby obtaining a brazed joint with excellent performance and stable structure.

[0044] Specifically, the brazing connection is performed under vacuum or a protective atmosphere; if necessary, a low load pressure can be applied to improve interfacial contact and promote joint densification, the pressure being 0-5 MPa or lower contact clamping conditions; post-weld cooling methods can be furnace cooling, furnace-side cooling, or controlled cooling rate to avoid additional thermal stress caused by thermal expansion mismatch.

[0045] In one embodiment, the brazing temperature of the nickel-based brazing filler metal is 1050~1125℃, and the brazing holding time is 30~180min.

[0046] In this embodiment, the brazing temperature needs to be maintained above the liquidus line of the nickel-based brazing filler metal but below the melting point of the base metal. The holding time can be set according to the requirements of interfacial diffusion and isothermal solidification. Appropriately increasing the temperature is beneficial to interfacial diffusion and metallurgical bonding, thereby improving the joint density. However, excessively high temperatures can lead to excessive interfacial reaction and coarsening of the microstructure, thereby reducing the joint performance. Appropriately extending the holding time is beneficial to promoting interfacial diffusion and pore closure, while excessively long holding times can lead to excessive interfacial reaction and an increase in brittle phases, thereby reducing the joint performance.

[0047] Furthermore, the brazing holding time is preferably 60~150 min.

[0048] In the following embodiments, the composite brazing filler metals are all prepared by mechanically mixing a nickel-based brazing filler metal matrix with refractory multi-principal element alloy powder. Brazing is performed in a vacuum brazing furnace. After grinding and cleaning, the samples are assembled, heated and held at a suitable contact pressure, and then cooled with the furnace. All applied welding pressures are contact pressures, and the vacuum degree is below 1×10⁻⁶. - 2 pa.

[0049] In the nickel-based solders of the following embodiments, the solder matrix used includes 89% Ni, 6wt% Cr, 2wt% Si, 2wt% B, and 1wt% Fe.

[0050] It should be noted that in the following embodiments, the EDS energy spectrum detection of the welded joint is limited by the detection method. The detection accuracy of Si and B is not high and cannot reflect the actual distribution of elements in this invention. Therefore, the energy spectrum analysis diagrams of the two elements are not shown in the accompanying drawings.

[0051] Example 1 10 wt% TiZrNbTa (1:1:1:1) and refractory multi-principal element alloy powder (particle size 10~20 μm) were added to a NiCrSiB matrix. The solder was then uniformly spread on the interface to be soldered, and the soldering was carried out under a vacuum degree ≤1×10 -3 Under Pa conditions, brazing was performed at 1075℃ for 90 minutes using a contact pressure assembly method, followed by furnace cooling.

[0052] The welded joint obtained in this embodiment was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 1 As shown in the figure, the interfacial microstructure of the welded joint is improved, and the continuity of the reaction layer is interrupted, indicating that the multi-principal-element particles have a certain regulatory effect on the interfacial reaction.

[0053] Example 2 5wt% WMoTaNb (1.05:1:1:1) and refractory multi-principal element alloy powder (particle size 10~20 μm) were added to the NiCrSiB matrix and brazed at 1050℃ for 90 min.

[0054] The welded joint obtained in this embodiment was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 2 As shown in the figure, the reaction layer is segmented by the solder, indicating that a low particle content can also play a certain role in regulating the interface structure, and a clear reaction layer still exists at the interface.

[0055] Example 3 20 wt% WMoTaNb (1:1:1:0.95) refractory multi-principal element alloy powder (particle size 10~20 μm) was added to the NiCrSiB matrix and brazed at 1050 ℃ for 90 min.

[0056] The welded joint obtained in this embodiment was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 3 As shown, by Figure 3 It can be seen that under the operating conditions and brazing filler metal composition settings of this embodiment, the microstructure of the welding interface is significantly refined, and the density of the brazing seam is improved; the nickel-based brazing filler metal containing refractory multi-principal element alloys in this embodiment is subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 4 In nickel-based brazing filler metals, the elements in the refractory multi-principal alloy powder are evenly distributed.

[0057] Example 4 This embodiment is based on embodiment 3, but the brazing temperature is increased to 1075℃ and the holding time is maintained for 90 minutes.

[0058] The welded joint obtained in this embodiment was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 5 As shown in the figure, both the interface diffusion effect and the degree of tissue homogenization are improved.

[0059] Example 5 Based on Example 4, the heat preservation time was extended to 150 min.

[0060] The welded joint obtained in this embodiment was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 6 As shown, Figure 6 It can be seen that the welded joint interface in this embodiment is the most dense and uniform, and the joint performance reaches the optimal level.

[0061] Example 6 The difference between this embodiment and Embodiment 3 is that the amount of refractory multi-principal alloy added is 30 wt%.

[0062] Comparative Example 1 NiCrSiB was used as the solder matrix, without the addition of refractory multi-principal element alloy powder, and the solder particle size was 10~20μm. The solder was uniformly spread on the interface to be soldered, and the soldering was carried out under a vacuum degree ≤1×10⁻⁶. -3 Under Pa conditions, brazing was performed at 1075℃ for 90 min using a contact pressure assembly method, followed by furnace cooling.

[0063] The welded joint obtained in this comparative example was subjected to scanning electron microscopy and energy dispersive spectroscopy analysis, and the results are as follows: Figure 7 As shown. In Figure 7 In the figure, a continuous interfacial reaction layer can be observed, and there is a certain brittle phase distribution. The overall performance of the joint is poor. It should be noted that the W and Co elements in the energy dispersive spectroscopy (EDS) analysis of this comparative example are from the substrate to be soldered, rather than from the solder itself.

[0064] Comparative Example 2 The difference between this comparative example and Example 5 is that the molar ratio of WMoTaNb in the refractory multi-principal alloy is 1:1:2:1.

[0065] Test case The shear strength of the welded joints in Examples 1-6 and Comparative Examples 1-2 was tested using the following method: The brazed joints were tested for room temperature shear strength using a universal testing machine at a compression shear rate of 1 mm / min. Three shear values ​​were taken as the average shear strength. The brazing filler metal and welding parameters, as well as the test results, in Examples 1-6 and Comparative Examples 1-2 are shown in Table 1.

[0066] Table 1 This invention introduces refractory multi-principal alloy powder WMoTaNb into NiCrSiB nickel-based brazing filler metal and, combined with reasonable process parameter control, achieves a significant improvement in joint performance. The joint shear strength can reach up to 424 MPa, which is significantly better than that of traditional brazing filler metal systems. It can be seen that refractory multi-principal alloy powder has a significant effect on controlling interface structure and relieving thermal stress.

[0067] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A nickel-based brazing filler metal containing a refractory multi-principal-element alloy, characterized in that, The nickel-based solder comprises a solder matrix and a refractory multi-principal alloy powder, wherein the refractory multi-principal alloy powder comprises: The material contains at least two of W, Mo, Ta, and Nb, and includes at least one of V, Ti, Hf, Zr, Cu, Ni, and Co, or excludes V, Ti, Hf, Zr, Cu, Ni, and Co.

2. The nickel-based brazing filler metal containing a refractory multi-principal-element alloy according to claim 1, characterized in that, In the refractory multi-principal-element alloy powder, the molar ratio between any two elements is 0.95~1.

05.

3. The nickel-based brazing filler metal containing a refractory multi-principal-element alloy according to claim 1, characterized in that, The nickel-based brazing filler metal contains 5-30% refractory multi-principal alloy powder by mass percentage.

4. The nickel-based brazing filler metal containing a refractory multi-principal-element alloy according to claim 1, characterized in that, The nickel-based brazing filler metal contains 7-20% refractory multi-principal alloy powder by mass percentage.

5. The nickel-based brazing filler metal containing a refractory multi-principal-element alloy according to claim 1, characterized in that, By weight percentage, the solder matrix Includes: Cr: 0~12wt%, Si: 1~3wt%, B: 1~3wt%, Fe≤5%, balance Ni.

6. The nickel-based brazing filler metal containing a refractory multi-principal-element alloy according to claim 1, characterized in that, The particle size range of the nickel-based brazing filler metal is 5~60μm.

7. A method for preparing a nickel-based solder containing a refractory multi-principal-element alloy, characterized in that, Includes the following steps: S1. Weigh out the brazing filler metal matrix and refractory multi-principal element alloy powder according to the mass percentage; S2. Grind and mix the material weighed in step S1 to obtain a nickel-based brazing filler metal containing a refractory multi-principal alloy.

8. The application of a nickel-based brazing filler metal containing a refractory multi-principal alloy as described in any one of claims 1 to 6, or a nickel-based brazing filler metal containing a refractory multi-principal alloy prepared by the preparation method described in claim 7, in dissimilar alloy joining.

9. The application of the nickel-based solder according to claim 8, characterized in that, The connection process involves applying the nickel-based brazing filler metal to the area to be brazed and then performing the brazing connection in a vacuum environment.

10. The application of the nickel-based solder according to claim 9, characterized in that, The brazing temperature of the nickel-based brazing filler metal is 1050~1125℃, and the brazing holding time is 30~180min.

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