Brazing method for multi-component brazing filler metal, composite ceramic and titanium alloy
A multi-component brazing filler metal composed of Zr, Cu, Ni, Nb and Ti in a specific ratio is used for vacuum brazing of silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloys to form TiC and ZrC stress transition layers, solving the problem of insufficient strength of welded joints in the existing technology and achieving high-strength welding at low temperatures.
Patent Information
- Application Number
- CN202511081671.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-04
- Publication Date
- 2025-09-30
AI Technical Summary
In the connection between silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloys, it is difficult to obtain high-strength weld joints with existing technologies, and traditional welding processes are prone to cracks and thermal stress concentration.
By using multi-component brazing filler metals with specific proportions, including Zr, Cu, Ni, Nb and Ti, a TiC and ZrC stress transition layer is formed at a lower temperature through vacuum brazing, achieving metallurgical bonding, inhibiting the precipitation of brittle phases and improving the strength of the welded joint.
A higher strength weld joint is obtained at a lower temperature, which reduces the risk of cracks and improves the overall plasticity and stress absorption capacity of the weld joint.
Smart Images
Figure CN120715484A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of welding technology, in particular to a method for brazing a multi-component brazing material, a composite ceramic and a titanium alloy. Background Art
[0002] Titanium and titanium alloys are high-performance engineering materials with the advantages of high strength, low density, corrosion resistance, fatigue resistance, and excellent high and low temperature performance. They are widely used in aerospace, medical equipment and other fields. These characteristics make titanium alloys irreplaceable in high-end fields. Brazing processing can effectively control welding residual stress and residual deformation, and achieve precision forming of complex components.
[0003] SiC f SiC (silicon carbide fiber reinforced silicon carbide composite ceramic) is a commonly used continuous fiber reinforced composite material. This material uses continuously textured SiC fibers to reinforce and toughen a SiC ceramic matrix, thereby forming a composite material with SiC fibers as the reinforcement phase and SiC ceramic as the matrix phase and continuous phase. It has the advantages of high high-temperature strength, low density, strong oxidation resistance, creep resistance, and good thermal stability, making it suitable for high-end fields such as aerospace and nuclear energy. However, its processing performance is poor, making it difficult to process into complex components for use in complex environments. When used, it needs to be connected to other materials. However, silicon carbide fiber reinforced silicon carbide composite ceramics are prone to cracking during welding, and the wide heat-affected zone of the weld can easily lead to local thermal stress concentration, further exacerbating the risk of cracking. It is not suitable for traditional welding processes and requires the use of special connection techniques.
[0004] At present, non-metallurgical bonding methods such as bonding are often used to connect silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloys. Although this type of connection method is simple and easy, it often cannot achieve high strength for the bonding of the workpieces. At the same time, the adhesive is prone to failure in high-temperature environments. However, due to the large difference in thermal expansion coefficients between silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloys, extremely large residual stress will be generated in the joint, resulting in lower joint strength. Summary of the Invention
[0005] The problem solved by the present invention is: how to obtain a higher-strength welding joint for brazing silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloy.
[0006] To solve the above problems, the present invention provides a multi-component solder, which comprises, by weight percentage, Zr: 30.0% to 40.0%, Cu: 10.0% to 20.0%, Ni: 5.0% to 15.0%, Nb: 2.0% to 20.0%, and the balance is Ti.
[0007] Optionally, the multi-component solder is smelted from Zr, Cu, Ni, Nb and Ti.
[0008] Compared to related technologies, the present invention provides a multi-component brazing filler metal composed of Zr, Cu, Ni, Nb, and Ti in specific ratios. When used to braze silicon carbide fiber-reinforced silicon carbide composite ceramics with titanium alloys, Ti, as a homogenous element with the Ti alloy, forms a uniform interface with the Ti alloy. Furthermore, as an active element, Ti readily reacts with the ceramic matrix, forming a TiC layer with a thermal expansion coefficient intermediate between the two matrix materials (ceramic matrix and titanium alloy matrix), enabling a good metallurgical bond between the Ti alloy and the ceramic matrix. Zr is infinitely miscible with β-Ti and exhibits excellent compatibility with titanium alloys. Furthermore, Zr has a good affinity for carbon and readily reacts with the ceramic matrix to form ZrC with a thermal expansion coefficient intermediate between the two matrix materials, forming a stress transition layer that facilitates the production of a high-strength weld joint. Cu, a typical melting point-depressing element, can effectively lower the overall melting point of the solder, allowing the brazing process to proceed at lower temperatures. However, excessive Cu can form brittle phases with elements such as Ti. Therefore, in the present invention, its addition is controlled to 10.0% to 20.0%. The introduction of Ni can effectively inhibit the precipitation of brittle crystalline phases (Laves phases) during the cooling process, thereby enhancing the solder's ability to form an amorphous state. However, Ni has a strong affinity with elements such as Si, easily reacting to form brittle compounds. Furthermore, excessive addition can corrode the base material. Therefore, in the present invention, its addition is controlled to 5.0% to 15.0%. Nb has a high melting point, high plasticity, and high compatibility with Ti. It can partially replace Ti and Zr, causing lattice distortion. Nb can also inhibit the formation of brittle phases during brazing, increasing the overall plasticity of the weld and enhancing its absorption of residual stresses, thus facilitating the production of higher-strength weld joints. In summary, the brazing filler metal provided by the present invention is used for brazing silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloys, and a higher strength weld joint can be obtained at a lower temperature.
[0009] The present invention also provides a method for brazing composite ceramics and titanium alloys, comprising: Step S1, stacking and assembling silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in sequence to obtain a workpiece to be welded; wherein the brazing filler metal is the multi-component brazing filler metal as described above; Step S2: Under vacuum conditions, heating the workpiece to be welded to a welding temperature at a preset heating rate, keeping the temperature for a preset time, and cooling it to room temperature to obtain a welded joint.
[0010] Optionally, in step S1, the titanium alloy is selected from one of TC4 titanium alloy, TB2 titanium alloy, TA7 titanium alloy, TA8 titanium alloy, TiNi alloy, Ti2AlNb alloy and TC11 titanium alloy.
[0011] Optionally, in step S2, the preset heating rate is 8°C / min to 12°C / min, the welding temperature is 930°C to 940°C, and the preset time is 8 min to 12 min.
[0012] Optionally, in step S2, cooling to room temperature includes: cooling to 190° C. to 210° C. at a preset cooling rate, and then cooling to room temperature in the furnace.
[0013] Optionally, the preset cooling rate is 4°C / min to 6°C / min.
[0014] Optionally, in step S1, the thickness of the solder is 0.4 mm to 0.8 mm.
[0015] Optionally, in step S1, the thickness of the silicon carbide fiber reinforced silicon carbide composite ceramic is 5 mm to 20 mm.
[0016] Optionally, in step S1, the thickness of the titanium alloy is 5 mm to 15 mm.
[0017] Compared with the related art, the brazing method adopted in the present invention uses a multi-component brazing filler metal composed of Zr, Cu, Ni, Nb and Ti in a specific ratio for brazing silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloy, which can obtain a higher strength weld joint at a lower temperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 Schematic diagram of the brazing process of composite ceramics and titanium alloys in an embodiment of the present invention; Figure 2 is the DSC curve of the solder used in Example 1; Figure 3 This is a scanning electron microscope image of the welded joint prepared in Example 1. DETAILED DESCRIPTION
[0019] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0020] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.
[0021] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0022] It should be noted that the ceramic matrix mentioned in the present invention refers to a silicon carbide fiber reinforced silicon carbide composite ceramic matrix.
[0023] An embodiment of the present invention provides a multi-component solder, which comprises, by weight percentage, 30.0% to 40.0% Zr, 10.0% to 20.0% Cu, 5.0% to 15.0% Ni, 2.0% to 20.0% Nb, and the balance Ti.
[0024] An embodiment of the present invention provides a multi-component brazing filler metal composed of Zr, Cu, Ni, Nb, and Ti in specific ratios. When used to braze silicon carbide fiber-reinforced silicon carbide composite ceramics with titanium alloys, Ti, as a homogenous element with the Ti alloy, forms a uniform interface with the Ti alloy. Furthermore, as an active element, Ti readily reacts with the ceramic matrix, forming a TiC layer with a thermal expansion coefficient intermediate between the two matrix materials (the ceramic matrix and the titanium alloy matrix), enabling a good metallurgical bond between the Ti alloy and the ceramic matrix. Zr is infinitely miscible with β-Ti and has excellent compatibility with titanium alloys. Furthermore, Zr has a good affinity for carbon and readily reacts with the ceramic matrix to form ZrC with a thermal expansion coefficient intermediate between the two matrix materials, forming a stress transition layer that facilitates a high-strength weld joint. Cu, a typical melting point-depressing element, effectively lowers the overall melting point of the brazing filler metal, enabling the brazing process to proceed at lower temperatures. However, excessive Cu can form brittle phases with elements such as Ti. Therefore, in the embodiments of the present invention, the addition of Cu is controlled to 10.0% to 20.0%. The introduction of Ni can effectively inhibit the precipitation of brittle crystalline phase (Laves phase) during the cooling process, thereby improving the ability of the solder to form an amorphous state. However, Ni has a strong affinity with elements such as Si and is easy to react to form brittle compounds. In addition, excessive addition is easy to corrode the base material. Therefore, in the embodiment of the present invention, its addition amount is controlled to 5.0% to 15.0%. Nb has the characteristics of high melting point, high plasticity, and high compatibility with Ti. It can partially replace Ti and Zr, thereby causing lattice distortion. In addition, Nb can inhibit the formation of brittle phases during brazing, increase the overall plasticity of the weld, and enhance the absorption of residual stress, which is conducive to obtaining a higher strength weld joint. In summary, the brazing filler metal provided in the embodiment of the present invention is used for brazing silicon carbide fiber reinforced silicon carbide composite ceramics with titanium alloys, and a higher strength weld joint can be obtained at a lower temperature. In some embodiments of the present invention, illustratively, the multi-component solder is formed by smelting metal Zr, metal Cu, metal Ni, metal Nb and metal Ti.
[0025] like Figure 1 As shown, an embodiment of the present invention further provides a method for brazing a composite ceramic and a titanium alloy, comprising: Step S1, stacking and assembling silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in sequence to obtain a workpiece to be welded; wherein the brazing filler metal is the multi-component brazing filler metal as described above; Step S2: Under vacuum conditions, heating the workpiece to be welded to a welding temperature at a preset heating rate, keeping the temperature for a preset time, and cooling it to room temperature to obtain a welded joint.
[0026] The brazing method adopted in the embodiment of the present invention uses a multi-component brazing filler metal composed of Zr, Cu, Ni, Nb and Ti in a specific ratio for brazing silicon carbide fiber reinforced silicon carbide composite ceramics and titanium alloy, which can obtain a higher strength weld joint at a lower temperature.
[0027] In some embodiments of the present invention, in step S1, the titanium alloy is selected from one of TC4 titanium alloy, TB2 titanium alloy, TA7 titanium alloy, TA8 titanium alloy, TiNi alloy, Ti2AlNb alloy and TC11 titanium alloy.
[0028] In some embodiments of the present invention, in step S2, the preset heating rate is 8°C / min to 12°C / min, the welding temperature is 930°C to 940°C, and the preset time is 8 min to 12 min.
[0029] In some embodiments of the present invention, in step S2, cooling to room temperature includes: cooling to 190°C to 210°C at a preset cooling rate, and then cooling to room temperature in the furnace; the preset cooling rate is 4°C / min to 6°C / min.
[0030] In some embodiments of the present invention, in step S1, the thickness of the solder is 0.4 mm to 0.8 mm.
[0031] In some embodiments of the present invention, in step S1, the thickness of the silicon carbide fiber reinforced silicon carbide composite ceramic is 5 mm to 20 mm.
[0032] In some embodiments of the present invention, in step S1, the thickness of the titanium alloy is 5 mm to 15 mm.
[0033] The present invention is further described below with reference to specific embodiments.
[0034] Example 1 A1. Assemble silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in a top-down order to obtain a part to be welded; wherein, the components of the brazing filler metal include, by weight percentage, Zr: 36.0%, Cu: 14.5%, Ni: 9.6%, Nb: 3.9%, and the balance is Ti; the brazing filler metal is in the form of a sheet with a thickness of 0.6 mm, the silicon carbide fiber reinforced silicon carbide composite ceramic is in the form of a sheet with a thickness of 12 mm, and the titanium alloy is made of TC4 titanium alloy, in the form of a sheet with a thickness of 10 mm.
[0035] A2. Under vacuum conditions, heat the workpiece to be welded to the welding temperature at a preset heating rate and keep it at that temperature for a preset time, cool it to 200°C at a preset cooling rate, and then cool it to room temperature in the furnace to obtain a welded joint; wherein the preset heating rate is 10°C / min, the welding temperature is 930°C, the preset time is 10 minutes, and the preset cooling rate is 5°C / min.
[0036] Example 2 A1. Assemble silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in a top-down order to obtain a part to be welded; wherein, the components of the brazing filler metal include, by weight percentage, Zr: 30.0%, Cu: 10.0%, Ni: 15.0%, Nb: 20%, and the balance is Ti; the brazing filler metal is in the form of a sheet with a thickness of 0.6 mm, the silicon carbide fiber reinforced silicon carbide composite ceramic is in the form of a sheet with a thickness of 12 mm, and the titanium alloy is made of TC4 titanium alloy, in the form of a sheet with a thickness of 10 mm.
[0037] A2. Under vacuum conditions, heat the workpiece to be welded to the welding temperature at a preset heating rate and keep it at that temperature for a preset time, cool it to 190°C at a preset cooling rate, and then cool it to room temperature in the furnace to obtain a welded joint; wherein the preset heating rate is 8°C / min, the welding temperature is 930°C, the preset time is 12 minutes, and the preset cooling rate is 4°C / min.
[0038] Example 3 A1. Assemble silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in a top-down order to obtain a part to be welded; wherein, the components of the brazing filler metal include, by weight percentage, Zr: 40.0%, Cu: 20.0%, Ni: 5.0%, Nb: 2.0%, and the balance is Ti; the brazing filler metal is in the form of a sheet with a thickness of 0.6 mm, the silicon carbide fiber reinforced silicon carbide composite ceramic is in the form of a sheet with a thickness of 12 mm, and the titanium alloy is made of TC4 titanium alloy, in the form of a sheet with a thickness of 10 mm.
[0039] A2. Under vacuum conditions, heat the workpiece to be welded to the welding temperature at a preset heating rate and keep it at that temperature for a preset time, cool it to 210°C at a preset cooling rate, and then cool it to room temperature in the furnace to obtain a welded joint; wherein the preset heating rate is 12°C / min, the welding temperature is 940°C, the preset time is 8 minutes, and the preset cooling rate is 6°C / min.
[0040] Comparative Example 1 The difference from Example 1 is that, in terms of weight percentage, the solder comprises the following components: Zr: 25%, Cu: 14.5%, Ni: 9.6%, Nb: 3.9%, and the balance is Ti.
[0041] Comparative Example 2 The difference from Example 1 is that, in terms of weight percentage, the solder comprises the following components: Zr: 36.0%, Cu: 14.5%, Ni: 9.6%, Nb: 1.0%, and the balance is Ti.
[0042] Comparative Example 3 The difference from Example 1 is that, in terms of weight percentage, the solder comprises: Zr: 36.0%, Cu: 14.5%, Ni: 9.6%, Mo: 3.9%, and the balance is Ti; that is, Nb in the composition is replaced by an equal amount of Mo.
[0043] Experimental example The solder used in Example 1 was characterized by DSC curve. Figure 2 ,from Figure 2 It can be seen that the brazing material used in Example 1 begins to transform from solid phase to liquid phase at 840℃. Therefore, the brazing process of Example 1 can be carried out at a lower welding temperature, that is, the welding temperature is about 50℃ below the phase transformation temperature of titanium alloy (990℃), which can avoid the damage of the base material due to excessive temperature during the welding process. The welding joint prepared in Example 1 was analyzed by scanning electron microscope, and the results are shown in FIG. Figure 3 ,from Figure 3 It can be seen that the weld joint prepared in Example 1 forms a continuous carbide layer on the side of the silicon carbide fiber reinforced silicon carbide composite ceramic base material, providing a stress transition between the weld and the ceramic base material. Although there is a clear interface on the titanium alloy side, the interface formed is uniform, indicating that the weld and the base material have high compatibility.
[0044] The shear strength of the welded joints prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was tested, and the results are shown in Table 1. It can be seen from Table 1 that the shear strength of the welded joints prepared in Examples 1 to 3 is higher than that in Comparative Examples 1 to 3.
[0045] Table 1
[0046] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.
Claims
1. A multi-component solder, characterized in that: Calculated by weight percentage, the components include: Zr: 30.0% to 40.0%, Cu: 10.0% to 20.0%, Ni: 5.0% to 15.0%, Nb: 2.0% to 20.0%, and the balance is Ti.
2. The multi-component solder according to claim 1, characterized in that: The multi-component solder is formed by smelting Zr, Cu, Ni, Nb and Ti.
3. A brazing method for composite ceramics and titanium alloys, characterized in that: include: Step S1, stacking and assembling silicon carbide fiber reinforced silicon carbide composite ceramics, brazing filler metal and titanium alloy in sequence to obtain a workpiece to be welded; wherein the brazing filler metal is the multi-component brazing filler metal according to claim 1 or 2; Step S2: Under vacuum conditions, heating the workpiece to be welded to a welding temperature at a preset heating rate, keeping the temperature for a preset time, and cooling it to room temperature to obtain a welded joint.
4. The brazing method of composite ceramic and titanium alloy according to claim 3, characterized in that: In the step S1, the titanium alloy is selected from one of TC4 titanium alloy, TB2 titanium alloy, TA7 titanium alloy, TA8 titanium alloy, TiNi alloy, Ti2AlNb alloy and TC11 titanium alloy.
5. The brazing method of composite ceramic and titanium alloy according to claim 3, characterized in that: In step S2, the preset heating rate is 8°C / min to 12°C / min, the welding temperature is 930°C to 940°C, and the preset time is 8 minutes to 12 minutes.
6. The brazing method of composite ceramic and titanium alloy according to claim 5, characterized in that: In the step S2, cooling to room temperature includes: cooling to 190° C. to 210° C. at a preset cooling rate, and then cooling to room temperature in the furnace.
7. The brazing method of composite ceramic and titanium alloy according to claim 6, characterized in that: The preset cooling rate is 4°C / min to 6°C / min.
8. The brazing method of composite ceramic and titanium alloy according to claim 3, characterized in that: In the step S1, the thickness of the solder is 0.4 mm to 0.8 mm.
9. The brazing method of composite ceramics and titanium alloy according to claim 3, characterized in that: In the step S1, the thickness of the silicon carbide fiber reinforced silicon carbide composite ceramic is 5 mm to 20 mm.
10. The brazing method of composite ceramics and titanium alloy according to claim 3, characterized in that: In step S1, the thickness of the titanium alloy is 5 mm to 15 mm.