A high-temperature-resistant active filler metal for brazing a SiC composite and a wrought superalloy

Abstract

This invention relates to the field of ceramic matrix composite welding technology, specifically to a high-temperature resistant active brazing filler metal for brazing SiC composite materials to wrought superalloys. The filler metal comprises the following components by weight percentage: Cr 14-17%, Co 10-12%, W 10-12%, Ti 5-7%, Al 4-5%, B 2.5-3.5%, with the balance being Ni. The purpose of this high-temperature resistant active brazing filler metal for brazing SiC composite materials to wrought superalloys is to solve the problem of poor high-temperature brazing performance of ceramic matrix composite materials.

Description

Technical Field

[0001] This invention relates to the field of ceramic matrix composite welding technology, specifically to a high-temperature resistant active brazing filler metal for brazing SiC composite materials to deformed high-temperature alloys. Background Technology

[0002] With the increasing operating temperatures of high-speed aircraft, new aero engines, and other new equipment, high-temperature resistant and lightweight SiC is becoming increasingly important. f / SiC (or C) f The application of SiC (SiC) ceramic matrix composites is becoming increasingly widespread, and the bonding between these composites and surrounding metal components has become a significant technical challenge. For example, SiC is used in components such as engine seals and regulating plates, particularly in high-temperature areas. f In the SiC composite material, the components driving the sealing and regulating plates are made of metal, and the operating temperature of the connection between the composite material and the metal does not exceed 900℃. To meet the high-temperature requirements of ceramic matrix composite / metal components, the metal material near the composite material is mainly a wrought high-temperature alloy. Due to the good chemical stability of ceramic matrix composites, conventional brazing filler metals for brazing high-temperature alloys cannot wet ceramic matrix composites, making direct brazing of ceramic matrix composites difficult. The coefficient of thermal expansion of ceramic matrix composites is small (approximately 4.6 × 10⁻⁶). -6 / ℃), and the high-temperature alloy connected to it has a large coefficient of thermal expansion (approximately 17×10). -6The significant difference in the coefficients of thermal expansion between dissimilar materials (°C) leads to a large difference in expansion on both sides of the weld during high-temperature brazing or use, resulting in substantial thermal stress. Simultaneously, due to the low plasticity of ceramic matrix composites, large-sized brazed joints are prone to cracking on the ceramic matrix composite side. To improve the service temperature and high-temperature strength of brazed joints, it is desirable to increase the brazing temperature and the amount of alloying elements added to the brazing filler metal. However, excessively high brazing temperatures can negatively impact the microstructure and properties of the high-temperature alloy base material. To minimize the impact of brazing on the microstructure and properties of the high-temperature alloy base material, the brazing temperature should not exceed the solution treatment temperature of the high-temperature alloy. For example, nickel-based high-temperature alloys such as GH3230 wrought high-temperature alloy and GH4950 wrought high-temperature alloy can operate at temperatures up to 950°C, with a solution treatment temperature of 1180°C; therefore, the brazing temperature should not exceed 1180°C. Mature brazing methods for ceramic matrix composites include ceramic metallization, silver-based active brazing filler metal (APLM), and titanium-based active brazing filler metal (TILM). Ceramic metallization involves sintering a metallization layer onto the ceramic welding surface, containing elements such as Mo and Mn. However, Mo and Mn have poor high-temperature oxidation resistance, resulting in brazed joints with limited operating temperatures. AgCuTi active brazing filler metals can achieve brazing connections between ceramics and ceramic matrix composites, but Ag and Cu contain poor oxidation resistance and low high-temperature strength, also limiting the operating temperature of the brazed joints. Titanium-based active brazing filler metals include TiCuNi and TiZrCuN. Various brazing fillers with i-components are mainly used for brazing ceramics and ceramic matrix composites to titanium alloys. However, because Ti in titanium-based brazing fillers is an active metal, it easily reacts with elements such as H, O, and N in the air, affecting the operating temperature. At the same time, the brazed joint is made of titanium alloy, and titanium alloy welds have low softening strength at high temperatures. Therefore, the operating temperature of brazed joints formed by titanium-based active brazing fillers is not high, which is significantly different from the operating temperature of ceramic matrix composites and wrought high-temperature alloys. This limits the performance of ceramic matrix composites in terms of temperature resistance and cannot meet the connection requirements of high-temperature components in high-speed aircraft and new aero engines.

[0003] Therefore, the inventors provide a high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys. Summary of the Invention

[0004] (1) Technical problems to be solved This invention provides a high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys, solving the technical problem of poor high-temperature brazing performance of ceramic matrix composite materials.

[0005] (2) Technical solution This invention provides a high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys, comprising the following components by weight percentage: Cr 14-17%, Co 10-12%, W 10-12%, Ti 5-7%, Al 4-5%, B 2.5-3.5%, with the balance being Ni.

[0006] Furthermore, the composition is Cr 15.70%, Co 11.86%, W 10.50%, Ti 6.15%, Al 4.35%, and B 2.89%.

[0007] Furthermore, the melting temperature of the brazing filler metal is 1050–1140°C.

[0008] Furthermore, the melting temperature of the brazing filler metal is 1089–1105℃.

[0009] Furthermore, the high-temperature resistant active solder is an alloy powder.

[0010] Furthermore, the particle size of the alloy powder is -200 mesh.

[0011] (3) Beneficial effects In summary, this invention adds the active element Ti to the nickel-based brazing filler metal. During brazing, Ti reacts with SiC to form a metallization layer, enabling direct brazing wetting of the ceramic matrix composite material by the filler metal. The addition of Cr, Co, W, and Al to the nickel matrix for solid solution strengthening, and the reaction of Ti with B to form the TiB2 ceramic phase, increases the remelting temperature and high-temperature strength of the brazed joint. The addition of an appropriate amount of B adjusts the melting temperature of the filler metal to between 1050 and 1140°C, ensuring the brazing temperature does not exceed 1200°C, matching the heat treatment temperature of the paired high-temperature alloy. The high free energy of the Ti-B reaction means that during brazing, Ti in the liquid phase preferentially reacts with B to form the high-melting-point TiB2 ceramic phase, rapidly reducing the B content in the liquid phase. This results in a brazing remelting temperature exceeding 1200°C, achieving a high-temperature brazing connection between the ceramic matrix composite material and the deformed high-temperature alloy, thus improving the service temperature of the ceramic matrix composite structure. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention 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.

[0013] Figure 1 This is a schematic diagram of the reaction free energy of a common element with SiC provided in an embodiment of the present invention; Figure 2 This is a SiC provided in Embodiment 1 of the present invention.f Solid image of the brazing specimen of SiC composite material and GH3230 high temperature alloy; Figure 3 This is a SiC provided in Embodiment 1 of the present invention. f Microstructure of the brazed joint of SiC composite material and GH3230 high-temperature alloy; Figure 4 This is a SiC provided in Embodiment 2 of the present invention. f Solid image of the brazing specimen of SiC composite material and GH4950 high-temperature alloy; Figure 5 This is a SiC provided in Embodiment 2 of the present invention. f Microstructure diagram of the brazed joint of SiC composite material and GH4950 high-temperature alloy. Detailed Implementation

[0014] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0016] This invention provides a high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys, comprising the following components by weight percentage: Cr 14-17%, Co 10-12%, W 10-12%, Ti 5-7%, Al 4-5%, B 2.5-3.5%, with the balance being Ni.

[0017] In the above embodiments, the brazing reaction free energy of ceramic matrix composite (SiC) was calculated and plotted. Figure 1The free energy curves of the reactions of active elements Ti, Zr, and Hf with SiC ceramics are shown. Combined with the Ni-Cr, Ni-Co, Ni-W, Ni-Al, and Ni-B phase diagrams, the content ranges of elements such as Cr, Co, W, Al, and B are determined. Comparing the free energy data of the reactions of active elements with SiC ceramics, Ti, with its high reaction free energy, is selected as the active element for the active solder to improve its wettability. Based on alloying theories such as solid solution strengthening and second-phase strengthening in high-temperature alloys, a nickel-based solder with Cr, Co, and W solid solution strengthening is proposed. Al is added to improve the oxidation resistance of the solder (weld), and B is added to lower the melting temperature of the solder. Specifically, Fe was removed to improve high-temperature oxidation resistance, C was removed to reduce the amount of carbides, and Si was removed to control the remelting temperature of the brazed weld. This results in a new high-temperature active solder, forming a high-entropy solder with five main components: NiCrCoWAl.

[0018] Furthermore, the composition is 15.70% Cr, 11.86% Co, 10.50% W, 6.15% Ti, 4.35% Al, 2.89% B, and the balance Ni. Using this specific mass ratio yields a high-temperature resistant active solder with superior performance.

[0019] As an optional implementation, the melting temperature of the brazing filler metal is 1050–1140℃, and the melting temperature of the brazing filler metal is 1089–1105℃. Considering the solution treatment temperature of GH3230 alloy is 1180℃, the brazing temperature does not exceed 1180℃, and the liquidus temperature of the brazing filler metal does not exceed 1140℃, thus matching the melting temperature of the brazing filler metal and the brazing temperature with the heat treatment of the metal materials being welded. The remelting temperature of the brazed joint reaches above 1200℃, achieving a high-temperature brazing connection between the ceramic matrix composite material and the deformed high-temperature alloy, thereby improving the service temperature of the ceramic matrix composite structure. The high-temperature resistant active brazing filler metal is an alloy powder with a particle size of -200 mesh.

[0020] Example 1 According to the designed solder composition, a powdered solder was manufactured using a vacuum smelting + atomization powdering process. The powder particle size was -200 mesh. The measured chemical composition of the powdered solder was: Ni balance, Cr 15.70, Co 11.86, W 10.50, Ti 6.15, Al 4.35, B 2.89. The tested melting temperature range of the solder was 1089–1105℃. The new solder was used for SiC... f Brazing tests were conducted on SiC ceramic matrix composites and GH3230 high-temperature alloy. The brazed samples are shown below. Figure 2 As shown, the brazed seam surface is continuous and the brazed fillet is obvious, achieving SiC f Direct brazing of SiC ceramic matrix composites with GH3230 high-temperature alloy; metallographic analysis of the brazed joints, such as... Figure 3As shown, the brazing interface is dense, and the joint microstructure consists of a nickel-based solid solution with massive carbides distributed within it. The brazing filler metal fills the SiC on the weld side. f / The gap in the SiC ceramic matrix composite material shows strip-shaped holes formed by fiber pull-out in the composite material area outside the brazing seam. Testing of SiC f The brazed joint of SiC ceramic matrix composite material and GH3230 high-temperature alloy achieved a shear strength of 125 MPa at 1100℃ (see Table 1 below), obtaining SiC f High-temperature brazing technology for SiC ceramic matrix composites and deformed high-temperature alloys.

[0021] Example 2 According to the designed solder composition, a powdered solder was manufactured using a vacuum smelting + atomization powdering process. The powder particle size was -200 mesh. The measured chemical composition of the powdered solder was: Ni balance, Cr 15.70, Co 11.86, W 10.50, Ti 6.15, Al 4.35, B 2.89. The tested melting temperature range of the solder was 1089–1105℃. The new solder was used for SiC... f Brazing tests of SiC ceramic matrix composites with GH4950 high-temperature alloy, brazing samples as follows: Figure 4 As shown, the brazed seam surface is continuous and the brazed fillet is obvious, achieving SiC f Direct brazing of SiC ceramic matrix composites with GH4950 high-temperature alloy; metallographic analysis of the brazed joints, such as... Figure 5 As shown, the brazing interface is dense, and the joint microstructure consists of a nickel-based solid solution with massive carbides distributed within it. The brazing filler metal fills the SiC on the weld side. f / The gap in the SiC ceramic matrix composite material shows strip-shaped holes formed by fiber pull-out in the composite material area outside the brazing seam. Testing of SiC f The brazed joint of SiC ceramic matrix composite material and GH4950 high-temperature alloy achieved a shear strength of 129 MPa at 1100℃ (see Table 2 below), obtaining SiC f High-temperature brazing technology for SiC ceramic matrix composites and deformed high-temperature alloys.

[0022] Table 1 SiC f / Shear strength of SiC and GH3230 alloy brazed joint Table 2 SiC f / Shear strength of SiC and GH4950 alloy brazed joint It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0023] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A high-temperature resistant active brazing filler metal for brazing SiC composite materials with wrought superalloys, characterized in that, The composition by weight percentage is as follows: Cr 14-17%, Co 10-12%, W 10-12%, Ti 5-7%, Al 4-5%, B 2.5-3.5%, with the balance being Ni.

2. The high-temperature-resistant active brazing material for brazing of SiC composite and wrought superalloy according to claim 1, characterized in that, Cr 15.70%, Co 11.86%, W 10.50%, Ti 6.15%, Al 4.35% and B 2.89%.

3. The high-temperature-resistant active brazing material for brazing SiC composites and wrought superalloys according to claim 1, characterized in that The melting temperature of the brazing filler metal is 1050–1140℃.

4. The high-temperature-resistant active brazing material for brazing SiC composites and wrought superalloys according to claim 2, characterized in that The melting temperature of the brazing filler metal is 1089–1105℃.

5. The high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys according to claim 1, characterized in that, The high-temperature resistant active brazing filler metal is an alloy powder.

6. The high-temperature resistant active brazing filler metal for brazing SiC composite materials and deformed high-temperature alloys according to claim 5, characterized in that, The alloy powder has a particle size of -200 mesh.

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