A brazing method of ZrB2-SiC-C ceramic composite and nickel-based superalloy

Abstract

A brazing method of ZrB2-SiC-C ceramic composite material and nickel-based high-temperature alloy relates to a brazing method of ceramic composite material and nickel-based high-temperature alloy. In order to solve the problems of difficult wetting of the filler metal to the ZrB2-SiC-C ceramic composite material base material, dissolution of the Ni element in the nickel-based high-temperature alloy into the filler metal, generation of a large amount of brittle compounds on the ZrB2-SiC-C ceramic composite material side interface, and large residual stress, the application adopts Cu-Ti filler metal to braze the ZrB2-SiC-C ceramic composite material and the nickel-based high-temperature alloy, the Ti in the Cu-Ti filler metal reacts with the ZrB2-SiC-C ceramic composite material to realize the wetting of the filler metal to the ceramic composite material base material, and the Nb foil is added in the Cu-Ti filler metal to block the diffusion of Ni and relieve the joint stress. On the basis of adding the Nb foil intermediate layer, the ZSC net structure is continuously added, which is beneficial to further promote the gradient transition of the thermal expansion coefficient of the ZSC ceramic composite material to the nickel-based high-temperature alloy, relieve the joint stress, hinder the crack propagation, realize the reliable connection of the ZSC ceramic composite material and the nickel-based high-temperature alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to a brazing method of ceramic composite material and nickel-based superalloy. BACKGROUND

[0002] Ultra-high temperature ceramic composite material can serve in ultra-high temperature and harsh environment due to its stable properties. Typical ultra-high temperature ceramic composite materials include ZrB2-SiC, HfB2-SiC, ZrB2-SiC-C, etc. Compared with other ceramic composite materials, ZrB2-SiC-C ceramic composite material has a high melting point, high Young's modulus, high hardness, and good electrical and thermal conductivity and chemical corrosion resistance, making it have a more extensive application prospect in ultra-high temperature structural and functional materials with harsh service conditions requirements, such as high-speed aircraft aileron and engine nozzle in the field of aerospace. The excellent performance of ZrB2-SiC-C ceramic composite material is due to its constituent components. ZrB2 has a high melting point and good chemical stability, can maintain a high strength at high temperature, and has relatively good thermal shock resistance and oxidation resistance; the addition of SiC can effectively increase the high-temperature strength and fracture toughness of the ceramic composite material, and greatly improve the oxidation resistance of the material; the addition of a certain amount of C can greatly increase the thermal conductivity of the material, thereby improving the thermal shock resistance of the material. However, the connection of ZrB2-SiC-C ceramic composite material and metal is still needed for the manufacturing of large-size components. Nickel-based superalloy is widely used in high-temperature components in the field of aerospace such as aircraft jet engine due to its high strength and good oxidation resistance. Therefore, the reliable connection of ZrB2-SiC-C ceramic composite material and nickel-based superalloy, which are two important high-temperature materials, and the excellent mechanical performance of the joint have broad application prospects.

[0003] The connection of ultra-high temperature ceramic composite material and high-temperature alloy usually adopts brazing method. There are mainly three difficulties in the brazing connection of ZrB2-SiC-C ceramic composite material and nickel-based superalloy: (1) ZrB2-SiC-C ceramic composite material is composed of ZrB2, SiC and graphite three phases, and for brazing, it is necessary to ensure that the brazing filler metal realizes good wetting on the three phases at the same time. (2) Nickel-based superalloy is easy to dissolve into the brazing filler metal, resulting in a large amount of Ni element in the weld. The active nature of Ni element can easily lead to intergranular penetration of the weld metal to the ZrB2-SiC-C ceramic composite material, forming a brittle weak area within a certain range on the surface of the base material; (3) The linear expansion coefficient of ZrB2-SiC-C ceramic composite material is 7.5×10 -6 / ℃, while the linear expansion coefficient of nickel-based superalloy is 16-18×10 -6 / ℃, the difference between the two is large, which can cause large residual stress in the joint during cooling process, weakening the performance of the joint. SUMMARY

[0004] The present application proposes a brazing method of ZrB2-SiC-C ceramic composite material and nickel-based superalloy in order to solve three problems of difficult wetting of brazing filler metal to ZrB2-SiC-C ceramic composite material base material, generation of a large amount of brittle compounds on the ZrB2-SiC-C ceramic composite material side interface due to dissolution of Ni element in nickel-based superalloy into brazing filler metal, and excessive residual stress caused by mismatch of linear expansion coefficients of ZrB2-SiC-C ceramic composite material and nickel-based superalloy. The present application brazes ZrB2-SiC-C ceramic composite material and nickel-based superalloy by using Cu-Ti filler metal, and realizes wetting of brazing filler metal to ceramic composite material base material by using Ti in Cu-Ti filler metal as an active element to react with ZrB2-SiC-C ceramic composite material. The addition of Nb foil as a composite interlayer in Cu-Ti filler metal plays a role of blocking Ni diffusion and relieving joint stress. The addition of ZSC (ZrB2-SiC-C ceramic composite material) mesh structure on the basis of the addition of Nb foil interlayer is beneficial to further promote the gradient transition of the thermal expansion coefficients of ZSC ceramic composite material to nickel-based superalloy, plays a role of relieving joint stress and hindering crack propagation, and realizes reliable connection of ZSC ceramic composite material and nickel-based superalloy.

[0005] The brazing method of ZrB2-SiC-C ceramic composite material and nickel-based superalloy according to the present application is carried out according to the following steps:

[0006] I. Pre-welding polishing and cleaning treatment is performed on ZrB2-SiC-C ceramic composite material;

[0007] The pre-welding polishing and cleaning treatment method is that the welding surface of ZrB2-SiC-C ceramic composite material is polished step by step, and then is placed in a cleaning agent for ultrasonic cleaning for 5-60 min; the cleaned ZrB2-SiC-C ceramic composite material is placed in anhydrous ethanol or acetone for liquid sealing for standby use;

[0008] The cleaning agent is anhydrous ethanol or acetone;

[0009] II. Pre-welding polishing and cleaning treatment is performed on nickel-based superalloy;

[0010] The pre-welding polishing and cleaning treatment method is that the welding surface of nickel-based superalloy is polished step by step, and then is placed in a cleaning agent for ultrasonic cleaning for 5-60 min;

[0011] The cleaning agent is anhydrous ethanol or acetone;

[0012] III. Cu-Ti filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti filler metal is 10%-40%;

[0013] The preparation method of the Cu-Ti brazing filler metal is as follows: Cu powder and TiH2 powder are weighed and uniformly ground to obtain the Cu-Ti brazing filler metal;

[0014] Four, the Nb foil is polished and cleaned before welding; the thickness of the Nb foil is 50-200 mu m;

[0015] The polishing and cleaning method before welding is that the two surfaces of the Nb foil are polished step by step, and then are ultrasonically cleaned in a cleaning agent for 5-60 min after polishing, and finally are cleaned by using a solvent; the cleaning agent is anhydrous ethanol or acetone; the solvent is anhydrous ethanol or acetone;

[0016] Five, the assembly of the welded part: the ZrB2-SiC-C ceramic composite material, the Cu-Ti brazing filler metal, the Nb foil, the Cu-Ti brazing filler metal and the nickel-based high-temperature alloy are sequentially stacked and fixed to obtain a to-be-welded part;

[0017] Six, the to-be-welded part is placed in a vacuum brazing furnace for vacuum brazing, and the process is completed;

[0018] The process of the vacuum brazing is that the temperature is raised to 910-990 DEG C at a temperature raising rate of not more than 15 DEG C / min under vacuum, and then is cooled to room temperature at a temperature lowering rate of not more than 10 DEG C / min.

[0019] Another brazing method of the ZrB2-SiC-C ceramic composite material and the nickel-based high-temperature alloy is as follows:

[0020] One, the ZrB2-SiC-C ceramic composite material is polished and cleaned before welding;

[0021] The polishing and cleaning method before welding is that the to-be-welded surface of the ZrB2-SiC-C ceramic composite material is polished step by step, and then is ultrasonically cleaned in a cleaning agent for 5-60 min;

[0022] The cleaning agent is anhydrous ethanol or acetone;

[0023] Two, the nickel-based high-temperature alloy is polished and cleaned before welding;

[0024] The polishing and cleaning method before welding is that the to-be-welded surface of the nickel-based high-temperature alloy is polished step by step, and then is ultrasonically cleaned in a cleaning agent for 5-60 min; the cleaned nickel-based high-temperature alloy is placed in anhydrous ethanol or acetone for liquid sealing for standby;

[0025] The cleaning agent is anhydrous ethanol or acetone;

[0026] Three, the Cu-Ti brazing filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti brazing filler metal is 10%-40%.

[0027] The preparation method of the Cu-Ti brazing filler metal is as follows: Cu powder and TiH2 powder are weighed and then uniformly ground to obtain the Cu-Ti brazing filler metal;

[0028] Four, the Nb foil and ZrB2-SiC-C ceramic composite mesh are subjected to pre-weld polishing and cleaning treatment;

[0029] The thickness of the Nb foil is 50-200 mu m;

[0030] The preparation method of the ZrB2-SiC-C ceramic composite mesh is as follows: ZrB2-SiC-C ceramic composite is cut into a thin sheet with a thickness of 0.2-1 mm by wire cutting, a hole with a diameter of 0.2-1 mm is processed on the thin sheet by using a pulse laser, and the ZrB2-SiC-C ceramic composite mesh is obtained; the porosity of the ZrB2-SiC-C ceramic composite mesh is 5%-30%;

[0031] The pre-weld polishing and cleaning treatment method is as follows: the two surfaces of the Nb foil are polished step by step, and after polishing, the Nb foil is placed in a cleaning agent for ultrasonic cleaning for 5-60 min, and finally solvent cleaning is performed; the cleaning agent is anhydrous ethanol or acetone; the solvent is anhydrous ethanol or acetone;

[0032] Five, assembly of the welded part: the ZrB2-SiC-C ceramic composite, the Cu-Ti brazing filler metal, the ZrB2-SiC-C ceramic composite mesh, the Cu-Ti brazing filler metal, the Nb foil, the Cu-Ti brazing filler metal, and the nickel-based high-temperature alloy are sequentially stacked and fixed to obtain a to-be-welded part;

[0033] Six, the to-be-welded part is placed in a vacuum brazing furnace for vacuum brazing, and the process is completed;

[0034] The process of the vacuum brazing is as follows: under vacuum conditions, the temperature is raised at a temperature raising rate of not more than 15 ℃ / min to 910-990 ℃ and is kept for 1-40 min, and then the temperature is lowered at a temperature lowering rate of not more than 10 ℃ / min to room temperature.

[0035] The principle and beneficial effects of the present application are as follows:

[0036] The Nb foil interlayer is used in the brazing of the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy in the application, the brazing seam structure on the ZrB2-SiC-C ceramic composite side is mainly composed of Cu(s,s) and Cu-Ti compound phases, the dissolution of Ni in the nickel-based high-temperature alloy to the brazing filler on the ZrB2-SiC-C ceramic composite side is effectively blocked, the activity of the active element Ti in the brazing filler is solved due to the consumption of Ni, the problems such as the intergranular penetration of the weld metal produced by the reaction of Ni and Si to the ZrB2-SiC-C ceramic composite are avoided, meanwhile, the brazing seam structure is improved, and the generation amount of brittle compounds on the ZrB2-SiC-C ceramic composite side is reduced. -6 / ℃, which is between the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy, plays a role of transition of the linear expansion coefficient, thereby relieving the residual stress of the joint.

[0037] The ZrB2-SiC-C ceramic composite net structure is used in the brazing of the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy in the application, which is conducive to the formation of the gradient transition of the thermal expansion coefficient from the ZSC ceramic composite to the nickel-based high-temperature alloy, plays a role of further relieving the joint stress, and also absorbs part of the fracture work. In addition, when the crack expands in the ZrB2-SiC-C ceramic composite intermediate layer, the brazing filler metal infiltrated in the ceramic composite hole is needed, and the crack needs to consume more energy when expanding in the metal than when expanding in the ceramic composite, so the brazing filler metal in the mesh hole of the ZrB2-SiC-C ceramic composite net can hinder the crack expansion to a certain extent, further improving the shear strength of the joint. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is the brazing joint interface structure picture obtained from Example 1;

[0039] Figure 2 It is the joint interface structure picture obtained from Example 2;

[0040] Figure 3 It is the joint fracture morphology obtained from Example 2;

[0041] Figure 4 It is the element surface scanning picture of Ni, Ti and Cu in the joint obtained in Comparative Example 1. DETAILED DESCRIPTION

[0042] The technical scheme of the application is not limited to the following specific embodiments, and any reasonable combination of the specific embodiments is also included.

[0043] Specific embodiment one: the brazing method of ZrB2-SiC-C ceramic composite material and nickel-based superalloy is carried out according to the following steps:

[0044] I. polishing and cleaning treatment of ZrB2-SiC-C ceramic composite material before welding;

[0045] II. polishing and cleaning treatment of nickel-based superalloy before welding;

[0046] III. preparation of Cu-Ti filler metal; the mass fraction of TiH2 in the Cu-Ti filler metal is 10%-40%;

[0047] IV. polishing and cleaning treatment of Nb foil before welding; the thickness of the Nb foil is 50-200 μm;

[0048] V. assembly of the welded part: the ZrB2-SiC-C ceramic composite material, the Cu-Ti filler metal, the Nb foil, the Cu-Ti filler metal, and the nickel-based superalloy are stacked and fixed in sequence to obtain a to-be-welded part;

[0049] VI. placing the to-be-welded part into a vacuum brazing furnace for vacuum brazing, and the process is completed;

[0050] The process of the vacuum brazing is as follows: under vacuum condition, the temperature is raised to 910-990 ℃ at a temperature raising rate of not more than 15 ℃ / min and is kept for 1-40 min, and then the temperature is lowered to room temperature at a temperature lowering rate of 10 ℃ / min.

[0051] In the embodiment, the Nb foil interlayer is used in the brazing of the ZrB2-SiC-C ceramic composite material and the nickel-based superalloy, so that the microstructure of the brazing seam on the ZrB2-SiC-C ceramic composite material side is mainly composed of Cu(s,s) and Cu-Ti compound phase, the dissolution of Ni in the nickel-based superalloy into the filler metal on the ZrB2-SiC-C ceramic composite material side is effectively blocked, the activity of Ti, an active element, in the filler metal is solved by Ni, the reaction of Ni and Si to produce intercrystalline penetration of the welded metal into the ZrB2-SiC-C ceramic composite material is avoided, the microstructure of the brazing seam is improved, and the generation amount of brittle compounds on the ZrB2-SiC-C ceramic composite material side is reduced. In addition, the linear expansion coefficient of Nb is 8.5-12.3 × 10 -6 / ℃, which is between the ZrB2-SiC-C ceramic composite material and the nickel-based superalloy, and plays a role of transition of the linear expansion coefficient, thereby relieving the residual stress of the joint.

[0052] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the pre-welding polishing and cleaning treatment method in step one is that the surface to be welded of the ZrB2-SiC-C ceramic composite is polished step by step, and then is placed in a cleaning agent for ultrasonic cleaning for 5-60 min; the ZrB2-SiC-C ceramic composite after cleaning is placed in anhydrous ethanol or acetone for liquid sealing for standby; the cleaning agent is anhydrous ethanol or acetone.

[0053] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the pre-welding polishing and cleaning treatment method in step two is that the surface to be welded of the nickel-based high-temperature alloy is polished step by step, and then is placed in a cleaning agent for ultrasonic cleaning for 5-60 min; the cleaning agent is anhydrous ethanol or acetone.

[0054] Specific embodiment four: the difference between this embodiment and one of specific embodiments one to three is that the preparation method of the Cu-Ti filler metal in step three is that Cu powder and TiH2 powder are weighed and then are ground uniformly to obtain the Cu-Ti filler metal.

[0055] Specific embodiment five: the difference between this embodiment and one of specific embodiments one to four is that the pre-welding polishing and cleaning treatment method in step four is that the two surfaces of the Nb foil are polished step by step, and then are placed in a cleaning agent for ultrasonic cleaning for 5-60 min, and finally are cleaned by using a solvent; the cleaning agent is anhydrous ethanol or acetone; the solvent is anhydrous ethanol or acetone.

[0056] Specific embodiment six: the brazing method of the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy is performed according to the following steps:

[0057] I. the ZrB2-SiC-C ceramic composite is subjected to pre-welding polishing and cleaning treatment;

[0058] II. the nickel-based high-temperature alloy is subjected to pre-welding polishing and cleaning treatment;

[0059] III. the Cu-Ti filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti filler metal is 10%-40%;

[0060] IV. the Nb foil and the ZrB2-SiC-C ceramic composite mesh are subjected to pre-welding polishing and cleaning treatment; the thickness of the Nb foil is 50-200 μm;

[0061] The preparation method of the ZrB2-SiC-C ceramic composite net is as follows: the ZrB2-SiC-C ceramic composite is cut into a sheet with a thickness of 0.2-1 mm by wire cutting, a hole with a diameter of 0.2-1 mm is processed on the sheet by using a pulse laser, and the ZrB2-SiC-C ceramic composite net is obtained; and the porosity of the ZrB2-SiC-C ceramic composite net is 5%-30%.

[0062] V. Assembly of the welded part: the ZrB2-SiC-C ceramic composite, the Cu-Ti filler, the ZrB2-SiC-C ceramic composite net, the Cu-Ti filler, the Nb foil, the Cu-Ti filler, and the nickel-based high-temperature alloy are stacked and fixed in sequence to obtain a to-be-welded part;

[0063] VI. The to-be-welded part is placed into a vacuum brazing furnace to perform vacuum brazing, and the process is completed;

[0064] The process of the vacuum brazing is as follows: under a vacuum condition, the temperature is raised to 910-990 ℃ at a temperature raising rate of not more than 15 ℃ / min and is kept for 1-40 min, and then the temperature is lowered to room temperature at a temperature lowering rate of not more than 10 ℃ / min. In the embodiment, the brazing of the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy adopts the Nb foil intermediate layer, the microstructure of the brazing seam on the ZrB2-SiC-C ceramic composite side is mainly composed of Cu(s,s) and Cu-Ti compound phases, the dissolution of Ni in the nickel-based high-temperature alloy into the filler on the ZrB2-SiC-C ceramic composite side is effectively blocked, the activity of the active element Ti in the filler is solved by the consumption of Ni, the reaction between Ni and Si to produce intercrystalline penetration of the weld metal into the ZrB2-SiC-C ceramic composite is avoided, and the microstructure of the brazing seam is improved, and the generation amount of brittle compounds on the ZrB2-SiC-C ceramic composite side is reduced. In addition, the linear expansion coefficient of Nb is 8.5-12.3 × 10 -6 / ℃, which is between the ZrB2-SiC-C ceramic composite and the nickel-based high-temperature alloy, and plays a role of transition of the linear expansion coefficient, thereby relieving the residual stress of the joint.

[0065] The ZrB2-SiC-C ceramic composite material mesh structure is used in the brazing of the ZrB2-SiC-C ceramic composite material and the nickel-based superalloy, which is beneficial to form a gradient transition of the thermal expansion coefficient from the ZSC ceramic composite material to the nickel-based superalloy, further relieve the joint stress, and also absorb part of the fracture work. In addition, the brazing filler metal infiltrated in the pores of the ceramic composite material needs to be passed through when the crack expands in the middle layer of the ZrB2-SiC-C ceramic composite material mesh, and the crack needs to consume more energy when it expands in the metal than when it expands in the ceramic composite material, so the brazing filler metal in the pores of the ZrB2-SiC-C ceramic composite material mesh can hinder the crack propagation to some extent, further improving the shear strength of the joint.

[0066] Specific embodiment seven: different from the specific embodiment six, the pre-welding polishing and cleaning treatment method in step one is that the welding surface of the ZrB2-SiC-C ceramic composite material is polished step by step, and then ultrasonic cleaning is performed in a cleaning agent for 5-60 min; the cleaning agent is anhydrous ethanol or acetone.

[0067] Specific embodiment eight: different from the specific embodiment six or seven, the pre-welding polishing and cleaning treatment method in step two is that the welding surface of the nickel-based superalloy is polished step by step, and then ultrasonic cleaning is performed in a cleaning agent for 5-60 min; the cleaned nickel-based superalloy is sealed in anhydrous ethanol or acetone for standby; the cleaning agent is anhydrous ethanol or acetone.

[0068] Specific embodiment nine: different from one of the specific embodiments six to eight, the preparation method of the Cu-Ti filler metal in step three is that Cu powder and TiH2 powder are weighed and then uniformly ground to obtain the Cu-Ti filler metal.

[0069] Specific embodiment ten: different from one of the specific embodiments six to nine, the pre-welding polishing and cleaning treatment method in step four is that the two surfaces of the Nb foil are polished step by step, and then ultrasonic cleaning is performed in a cleaning agent for 5-60 min, and finally solvent cleaning is performed; the cleaning agent is anhydrous ethanol or acetone; the solvent is anhydrous ethanol or acetone.

[0070] Example 1

[0071] The brazing method of the ZrB2-SiC-C ceramic composite material and the nickel-based superalloy in this embodiment is carried out according to the following steps:

[0072] I. Pre-welding polishing and cleaning treatment is performed on the ZrB2-SiC-C ceramic composite material;

[0073] The pre-weld polishing and cleaning treatment method is: cutting the ZrB2-SiC-C ceramic composite into a test piece with a size of 4mm*4mm*3mm, sequentially polishing the surface to be welded of the ZrB2-SiC-C ceramic composite by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh diamond sandpaper, and then ultrasonic cleaning in a cleaning agent for 15 minutes after polishing; the cleaned ZrB2-SiC-C ceramic composite is placed in anhydrous ethanol for liquid sealing for standby;

[0074] The cleaning agent is anhydrous ethanol;

[0075] II. The nickel-based superalloy is subjected to pre-weld polishing and cleaning treatment;

[0076] The pre-weld polishing and cleaning treatment method is: cutting the nickel-based superalloy into a test piece with a size of 20mm*10mm*2mm, sequentially polishing the surface to be welded of the nickel-based superalloy by using 400-mesh and 800-mesh diamond sandpaper, and then ultrasonic cleaning in a cleaning agent for 15 minutes after polishing; the cleaned nickel-based superalloy is placed in anhydrous ethanol for liquid sealing for standby;

[0077] The cleaning agent is anhydrous ethanol;

[0078] The nickel-based superalloy is GH99 high-temperature alloy;

[0079] III. A Cu-Ti filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti filler metal is 25%;

[0080] The preparation method of the Cu-Ti filler metal is: weighing Cu powder and TiH2 powder, and then grinding uniformly to obtain the Cu-Ti filler metal;

[0081] IV. The Nb foil is subjected to pre-weld polishing and cleaning treatment; the thickness of the Nb foil is 80μm;

[0082] The pre-weld polishing and cleaning treatment method is: sequentially polishing the two surfaces of the Nb foil by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh diamond sandpaper, ultrasonic cleaning in a cleaning agent for 15 minutes after polishing, and finally using a solvent for cleaning; the cleaning agent is anhydrous ethanol; and the solvent is anhydrous ethanol;

[0083] V. Assembly of the welded part: sequentially stacking and fixing the ZrB2-SiC-C ceramic composite, the Cu-Ti filler metal, the Nb foil, the Cu-Ti filler metal and the nickel-based superalloy to obtain a welded part;

[0084] VI. Placing the welded part into a vacuum brazing furnace for vacuum brazing, and the process is completed;

[0085] The vacuum brazing process is: under vacuum condition, heating to 950℃ at a heating rate of 15℃ / min and holding for 10min, and then cooling to room temperature at a cooling rate of 5℃ / min.

[0086] The shear strength of the connecting joint obtained in Example 1 reaches 85MPa at room temperature by using an electronic universal testing machine for shear test at a loading speed of 0.5mm / min. Figure 1 The interface structure picture of the brazing joint obtained in Example 1 contains the enlarged pictures of A, B and D zones in the brazing joint; the picture is obtained by Figure 1 The results show that the joint is well connected, and the energy spectrum analysis of the joint shows that the reaction products on the ZSC ceramic composite side of the joint are Ti-Si, Ti-Si-C, Ti-C and Ti-Cu compounds, which indicates that the Nb foil interlayer blocks the influence of the dissolution of Ni in GH99 on the brazing seam on the ZSC ceramic composite side. The brazing seam on the ZSC ceramic composite side is mainly formed by Cu(s,s) and Cu-Ti compound phases, and no brittle Ti-Ni compound is present, thereby ensuring the activity of the active element Ti in the brazing filler metal, and also improving the brazing seam structure and reducing the generation amount of brittle compounds on the ZSC base material side. In addition, the linear expansion coefficient of Nb is between that of the ZSC ceramic composite and the GH99 nickel-based superalloy, which plays a role in the transition of the linear expansion coefficient, thereby relieving the residual stress of the joint.

[0087] Table 1 Energy spectrum analysis data (at.%) at the joint interface

[0088]

[0089]

[0090] Example 2

[0091] The brazing method of the ZrB2-SiC-C ceramic composite and the nickel-based superalloy in this example is carried out according to the following steps:

[0092] I. Pre-weld polishing and cleaning treatment of the ZrB2-SiC-C ceramic composite;

[0093] The pre-weld polishing and cleaning treatment method is: cutting the ZrB2-SiC-C ceramic composite into a test piece with a size of 4mm×4mm×3mm, and using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh diamond sandpaper to polish the to-be-welded surface of the ZrB2-SiC-C ceramic composite step by step, and then placing it in a cleaning agent for ultrasonic cleaning for 15min; the cleaned ZrB2-SiC-C ceramic composite is placed in anhydrous ethanol for liquid sealing for standby;

[0094] The cleaning agent is anhydrous ethanol;

[0095] II. The nickel-based superalloy is subjected to pre-weld polishing and cleaning treatment;

[0096] The pre-weld polishing and cleaning treatment method is as follows: the nickel-based superalloy is cut into a test piece with a size of 20mmx10mmx2mm, the welding surface of the nickel-based superalloy is polished step by step using 400-mesh and 800-mesh diamond sandpaper, and after polishing, the nickel-based superalloy is placed in a cleaning agent for ultrasonic cleaning for 15 minutes; the cleaned nickel-based superalloy is placed in anhydrous ethanol for liquid sealing for standby;

[0097] The cleaning agent is anhydrous ethanol;

[0098] The nickel-based superalloy is GH99 high-temperature alloy;

[0099] III. A Cu-Ti filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti filler metal is 25%;

[0100] The preparation method of the Cu-Ti filler metal is as follows: Cu powder and TiH2 powder are weighed and then uniformly ground to obtain the Cu-Ti filler metal;

[0101] IV. The Nb foil and the ZrB2-SiC-C ceramic composite mesh are subjected to pre-weld polishing and cleaning treatment;

[0102] The pre-weld polishing and cleaning treatment method is as follows: the two surfaces of the Nb foil are sequentially polished step by step using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh diamond sandpaper, and after polishing, the Nb foil is placed in a cleaning agent for ultrasonic cleaning for 15 minutes, and finally solvent cleaning is performed; the cleaning agent is anhydrous ethanol; and the solvent is anhydrous ethanol;

[0103] The thickness of the Nb foil is 50-200μm;

[0104] The preparation method of the ZrB2-SiC-C ceramic composite mesh is as follows: the ZrB2-SiC-C ceramic composite is cut into a thin sheet with a thickness of 0.5mm using a wire cutting machine, a pulse laser is used to process holes with a diameter of 0.5mm on the thin sheet to obtain the ZrB2-SiC-C ceramic composite mesh; the porosity of the ZrB2-SiC-C ceramic composite mesh is 11%, and the holes are arranged in a square array with a spacing of 1mm between the holes;

[0105] V. Assembly of the welded part: the ZrB2-SiC-C ceramic composite, the Cu-Ti filler metal, the ZrB2-SiC-C ceramic composite mesh, the Cu-Ti filler metal, the Nb foil, the Cu-Ti filler metal and the nickel-based superalloy are sequentially stacked and fixed to obtain a welding part;

[0106] VI. The welding part is placed in a vacuum brazing furnace for vacuum brazing, and the process is completed;

[0107] The process of vacuum brazing is as follows: under vacuum condition, heating to 450℃ at a heating rate of 15℃ / min and holding for 30min, then heating to 750℃ at a heating rate of 10℃ / min and holding for 20min, then heating to 950℃ at a heating rate of not more than 5℃ / min and holding for 10min, and then cooling to room temperature at a cooling rate of 5℃ / min.

[0108] The shear strength of the connecting joint obtained in Example 2 reaches 107MPa at room temperature by using an electronic universal testing machine for shear test at a loading speed of 0.5mm / min. Figure 2 joint interface analysis, Figure 3 The fracture analysis can see that the joint is broken in the ZSC ceramic composite material and the ZSC reticular interlayer, which shows that under the action of external force load, the crack is initiated in the ZSC reticular interlayer, and then expanded to the inside of the ZSC ceramic composite material. The crack path is deflected in the expansion process, which will absorb a part of the fracture work. In addition, the crack needs to pass through the brazing filler metal infiltrated in the ceramic composite material hole when expanding in the ZSC reticular interlayer, and the crack needs to consume more energy in the metal than in the ceramic composite material when expanding in the metal, so the brazing filler metal in the ceramic composite material hole will hinder the crack expansion to a certain extent. The ZrB2-SiC-C ceramic composite net makes the joint strength further improved.

[0109] Comparative Example 1

[0110] The brazing method of the ZSC ceramic composite material and the nickel-based superalloy in the present comparative example is carried out according to the following steps:

[0111] I. Pre-welding treatment of ZSC ceramic composite material (ZrB2-SiC-C ceramic composite material):

[0112] The ZSC ceramic composite material is cut into a test piece with a size of 4mm×4mm×3mm by wire cutting, and the surface of the ZSC ceramic composite material is polished by using 400-mesh, 800-mesh, 1500-mesh and 2000-mesh diamond sandpaper in turn. The treated ZSC ceramic composite material is ultrasonically cleaned in a cleaning agent for 15min. The cleaned ZSC ceramic composite material is liquid-sealed in anhydrous ethanol for standby.

[0113] II. Pre-welding treatment of nickel-based superalloy:

[0114] The GH99 high-temperature alloy is cut into a test piece with a size of 20mm×10mm×2mm. The surface of the GH99 high-temperature alloy is polished by using 400-mesh and 800-mesh diamond sandpaper in turn. The treated GH99 high-temperature alloy is ultrasonically cleaned in a cleaning agent for 15min. The cleaned nickel-based superalloy is liquid-sealed in anhydrous ethanol for standby.

[0115] III. Preparation of Cu-Ti filler metal

[0116] Cu powder and TiH2 powder with mass ratio of 3:1 were weighed using an electronic balance, and then were put into a mortar and ground to obtain a uniform mixed powder filler metal.

[0117] IV. Assembly of the welded part

[0118] The cleaned ceramic composite base material, the filler metal, and the metal base material were stacked in the order of top to bottom on a stone grinding disc, and then were fixed with a pressing block and placed in a vacuum furnace.

[0119] V. The parts to be welded were placed in a vacuum brazing furnace for vacuum brazing to complete the brazing of the ZSC ceramic composite material and the nickel-based high-temperature alloy;

[0120] The process of vacuum brazing was as follows: under vacuum conditions, the temperature was raised to 950℃ at a rate of 15℃ / min and was kept for 10 min, and then was cooled to room temperature at a rate of 5℃ / min.

[0121] Shear test was performed using an electronic universal testing machine at a loading speed of 0.5 mm / min. The shear strength of the joint obtained in Comparative Example 1 at room temperature was 24 MPa. It can be found from Figure 4 Elemental mapping of the joint showed that, due to the strong affinity between Ni and Ti, a large amount of Ni element in the GH99 base material dissolved into the filler metal during brazing, combined with Cu and Ti elements in the center of the weld to form a continuous layered Cu-Ti-Ni ternary compound, thereby increasing the brittleness of the joint and adversely affecting the strength.

Claims

1. A brazing method of a ZrB2-SiC-C ceramic composite and a nickel-based superalloy, characterized by: The brazing method of ZrB2-SiC-C ceramic composite and nickel-based superalloy is carried out according to the following steps: I. The ZrB2-SiC-C ceramic composite is polished and cleaned before welding; II. The nickel-based superalloy is polished and cleaned before welding; III. The Cu-Ti filler metal is prepared; the mass fraction of TiH2 in the Cu-Ti filler metal is 10%-40%; IV. The Nb foil and the ZrB2-SiC-C ceramic composite mesh are polished and cleaned before welding; the thickness of the Nb foil is 50-200 μm; The preparation method of the ZrB2-SiC-C ceramic composite mesh is as follows: the ZrB2-SiC-C ceramic composite is cut into a thin sheet with a thickness of 0.2-1 mm by wire cutting, a hole with a diameter of 0.2-1 mm is processed on the thin sheet by using a pulse laser, and the ZrB2-SiC-C ceramic composite mesh is obtained; the porosity of the ZrB2-SiC-C ceramic composite mesh is 5%-30%; V. The assembly of the welding part: the ZrB2-SiC-C ceramic composite, the Cu-Ti filler metal, the ZrB2-SiC-C ceramic composite mesh, the Cu-Ti filler metal, the Nb foil, the Cu-Ti filler metal, and the nickel-based superalloy are stacked and fixed in sequence to obtain a welding part; VI. The welding part is placed in a vacuum brazing furnace for vacuum brazing, and the process is completed; The process of vacuum brazing is as follows: under vacuum conditions, the temperature is raised to 910-990 ℃ at a temperature rising rate of not more than 15 ℃ / min and is kept for 1-40 min, and then the temperature is lowered to room temperature at a temperature lowering rate of not more than 10 ℃ / min.

2. The brazing method of ZrB2-SiC-C ceramic composites to nickel-based superalloys according to claim 1, characterized in that: The polishing and cleaning method before welding in step I is as follows: the welding surface of the ZrB2-SiC-C ceramic composite is polished step by step, and then is ultrasonically cleaned in a cleaning agent for 5-60 min; the cleaning agent is anhydrous ethanol or acetone.

3. The method of brazing ZrB2-SiC-C ceramic composites to nickel-based superalloys according to claim 1, characterized in that: The polishing and cleaning method before welding in step II is as follows: the welding surface of the nickel-based superalloy is polished step by step, and then is ultrasonically cleaned in a cleaning agent for 5-60 min; the nickel-based superalloy after cleaning is sealed in anhydrous ethanol or acetone for standby; the cleaning agent is anhydrous ethanol or acetone.

4. The method of brazing ZrB2-SiC-C ceramic composites to nickel-based superalloys according to claim 1, characterized in that: The preparation method of the Cu-Ti filler metal in step III is as follows: Cu powder and TiH2 powder are weighed and then are uniformly ground to obtain the Cu-Ti filler metal.

5. The method of brazing ZrB2-SiC-C ceramic composites to nickel-based superalloys according to claim 1, characterized in that: The polishing and cleaning method before welding in step IV is as follows: the two surfaces of the Nb foil are polished step by step, and then are ultrasonically cleaned in a cleaning agent for 5-60 min, and finally are cleaned with a solvent; the cleaning agent is anhydrous ethanol or acetone; the solvent is anhydrous ethanol or acetone.

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