Titanium-containing active brazing filler metal strip and preparation method thereof

Abstract

The invention belongs to the technical field of metal connecting materials, and particularly relates to a titanium-containing active brazing filler metal strip and a preparation method thereof. The invention aims to solve the technical problems that the existing titanium-containing active brazing filler metal is easy to crack, the surface is oxidized and the dimensional precision is low when a thin strip is prepared due to high internal brittleness. The titanium-containing active brazing filler metal strip comprises the following components in percentage by mass: 1.5-5% of Ti, 0-5% of Sn, 0-1% of Ni, 20-30% of Cu and the balance of Ag. The preparation method comprises the following steps: 1) high vacuum melting; (2) homogenizing annealing; (3) 'multi-pass and small-reduction-rate 'plastic processing and intermediate annealing are carried out; according to the preparation method, the harmful effect of a brittle phase is effectively inhibited, cracking and oxidation in the machining process are avoided, the multi-element titanium-containing active brazing filler metal thin strip which is smooth in surface, uniform in thickness and excellent in performance is successfully prepared, the yield is high, and the preparation method is suitable for large-area brazing of precise devices.

Description

Technical Field

[0001] This invention belongs to the field of metal connection material technology, specifically relating to a titanium-containing active brazing filler strip and its preparation method. Background Technology

[0002] Active metal brazing is a key technology for achieving high-strength, airtight connections between dissimilar materials such as ceramics and metals. Its core lies in adding active elements such as Ti and Zr to the brazing filler metal. These elements can chemically react with non-metallic materials like ceramics during high-temperature brazing, generating a reaction layer with good wettability, thereby achieving metallurgical bonding. Among various active brazing filler metal systems, silver-copper-titanium (Ag-Cu-Ti) brazing filler metals have become one of the most extensively researched and widely used active brazing filler metals due to their excellent wettability with most ceramic materials, moderate melting point, and good overall joint performance.

[0003] With the development of high-tech fields such as aerospace, high-power semiconductor packaging (such as IGBT modules), and nuclear industry, more stringent requirements have been placed on the service performance of connectors. The classic Ag-Cu-Ti ternary eutectic composition can no longer fully meet all application scenarios. Therefore, the research on Ag-Cu-Ti solders has entered the stage of "refined composition customization." By adding fourth and fifth components, such as Sn, Ni, and In, the melting characteristics, wettability, flowability, mechanical properties, and oxidation resistance of the solders can be further optimized.

[0004] In practical applications, the physical morphology of the brazing filler metal is crucial to its process applicability. Compared to solder paste or welding wire, high-quality strips with thin thickness (<200μm), large size (width >10mm), and high surface finish are favored in the brazing of precision devices and structural components due to their advantages such as precise control of weld gap, large-area uniform material distribution, and ease of automated production. However, preparing high-quality strips from multi-component titanium-containing active brazing filler metals faces significant technical challenges, stemming from the inherent brittleness of the material.

[0005] Ti, the active element, has extremely low solid solubility in the Ag-Cu matrix. During alloy melting and solidification, it readily reacts with Cu to form a series of hard and brittle intermetallic compounds (IMCs), such as TiCu, Ti₂Cu₃, and TiCu₄. These brittle phases are dispersed throughout the alloy matrix, acting as microcrack initiation sites and significantly deteriorating the alloy's plasticity and machinability. Studies have shown that when the Ti content exceeds 4 wt.%, the alloy's toughness becomes very poor, making it difficult to process into finished products using conventional methods. Existing methods for preparing Ag-Cu-Ti based active solder strips and their limitations are as follows:

[0006] 1. Melting-Rolling Method: This is the most direct method for preparing metal strips. However, for Ag-Cu-Ti alloys with high Ti content, due to the presence of a large number of coarse, brittle Ti-Cu compounds in the as-cast microstructure, stress easily concentrates at the interface between these brittle phases and the matrix during rolling deformation. This leads to severe edge cracking or even overall breakage of the material with only a small amount of deformation, making it impossible to obtain complete and uniform thin strips. For example, patent CN114942971A discloses a method, but its description of how to systematically control the cracking problem of high Ti content alloys during rolling is not specific enough, and its operability needs improvement. Therefore, traditional high-reduction rolling processes are completely unsuitable for such materials.

[0007] 2. Powder Metallurgy: This method involves mixing Ag-Cu alloy powder with Ti powder, pressing, sintering, and then rolling. This method can bypass the macroscopic segregation problem during the smelting process, but the metal powder, especially active Ti powder, is easily oxidized, and residual porosity may exist in the sintered body, affecting the performance of the final product.

[0008] 3. Layered Composite Method: This method sandwiches Ti foil strips between Ag-Cu alloy sheets and rolls them together to create a "sandwich" structure. The resulting pre-alloyed solder is not homogeneous, and alloying during brazing may be insufficient, affecting the uniformity of the joint structure.

[0009] In summary, existing technologies face significant bottlenecks in the stable and mass production of multi-element, highly active solder strips with a thickness less than 200 μm and a width greater than 10 mm via smelting. The core challenge lies in effectively controlling the mechanical behavior of this inherently brittle material during the large plastic deformation process from ingot to thin strip. Simply employing traditional rolling processes easily leads to problems such as cracking, uneven thickness, and surface oxidation caused by multiple intermediate annealing processes, severely impacting product yield and quality.

[0010] In view of this, the present invention is hereby proposed. Summary of the Invention

[0011] The purpose of this invention is to provide a titanium-containing active brazing alloy strip and its preparation method, so as to solve the technical problems of easy cracking, easy oxidation and low yield of titanium-containing active brazing alloys in the rolling process of thin strips due to their poor plasticity and severe work hardening.

[0012] To achieve the above objectives, the technical solution of the present invention is as follows:

[0013] On one hand, this invention provides a titanium-containing active brazing alloy strip, comprising the following chemical composition by mass percentage: Ti: 1.5~5%, Sn: 0~5%, Ni: 0~1%, Cu: 20~30%, with the balance being Ag. In this composition system, Ti is the core element providing activity; Cu and Ag form a eutectic matrix; trace amounts of Ni (0~1%) can refine the grains and improve the microstructure, positively impacting the alloy's processing plasticity; Sn can lower the melting point of the brazing alloy and improve its fluidity. This invention optimizes the intrinsic plasticity of the alloy while ensuring brazing activity by precisely controlling the proportions of each element.

[0014] Furthermore, the composition design of this invention is not based on a simple "trial and error" method, but follows thermodynamic principles, particularly utilizing the enthalpy of formation between elements as a theoretical guide. The enthalpy of formation (ΔHƒ) is a key parameter for determining the stability of intermetallic compounds (IMCs) in an alloy. The more negative the value of the enthalpy of formation, the stronger the interatomic bonding, the higher the thermodynamic stability of the resulting compound, and the more likely it is to preferentially form during solidification. In the Ag-Cu-Ti ternary system, the formation of brittle Ti-Cu compounds is the main reason for its poor processability. The innovation of this invention in adding Ni lies in the fact that the enthalpy of formation of Ti-Ni compounds (such as Ni3Ti, ΔHƒ ≈ -35 kJ / mol·atom) is significantly more negative than that of Ti-Cu compounds (such as TiCu, ΔHƒ ≈ -9 kJ / mol·atom). According to this principle, during the cooling and solidification of the molten alloy, the active element Ti will preferentially react with Ni to form more stable Ti-Ni intermetallic compounds. This competitive formation mechanism effectively consumes a portion of the active Ti, thereby inhibiting or reducing the formation of larger, more destructive, coarse network or blocky Ti-Cu brittle phases. The resulting Ti-Ni phase is typically finer and more dispersed, causing less damage to the overall plasticity of the alloy. Therefore, by using the enthalpy of formation as a predictive tool for alloy design, the phase formation sequence during alloy solidification can be scientifically controlled, fundamentally improving the intrinsic brittleness of the material, reducing the R&D costs associated with blindly employing trial and error, and providing a theoretical basis for optimizing composition to improve processing performance.

[0015] On the other hand, the present invention provides a method for preparing the titanium-containing active solder strip as described above, comprising the following steps:

[0016] Step 1, High Vacuum Melting: After weighing the Ag, Cu, Ti, Sn, and Ni raw materials according to the designed composition, melt them under a vacuum degree lower than 5 × 10⁻⁶. -3 The alloy ingot is obtained by melting under Pa conditions. The key to this step is the high vacuum environment, which can effectively prevent the active element Ti from reacting with oxygen and nitrogen at high temperatures and becoming ineffective.

[0017] Step 2, Homogenization Annealing: The alloy ingot is subjected to homogenization annealing. The as-cast microstructure typically contains compositional segregation and coarse network or blocky Ti-Cu intermetallic compounds, which are the main causes of material brittleness. This step promotes the dissolution, dispersion, and spheroidization of the brittle phases, significantly improving the alloy's plasticity and laying the microstructure foundation for subsequent plastic processing.

[0018] Step 3, "Multi-pass, low-reduction" plastic processing and intermediate annealing: The homogenized annealed alloy ingot is subjected to multi-pass cold rolling, with the single-pass reduction rate controlled within 10%. When the total processing deformation reaches 30%~50%, a vacuum intermediate annealing is performed to achieve recrystallization and restore plasticity. The cycle of cold rolling and vacuum intermediate annealing is repeated until the strip thickness approaches the target size. This step is the core process of this invention. The key to cold rolling the homogenized annealed alloy ingot lies in strictly controlling the processing parameters: the single-pass reduction rate is controlled within 10%, preferably 3%~8%, to avoid excessive stress concentration around the brittle phase, thereby inhibiting the initiation and propagation of microcracks. Simultaneously, due to the work hardening effect, when the total deformation accumulates to 30%~50%, the material's plasticity is exhausted. At this point, a high-vacuum intermediate annealing must be performed to allow the material to recrystallize and restore plasticity.

[0019] Step 4, Finished product rolling and annealing: The strip is precision rolled to a thickness of 50-200 micrometers, and then vacuum annealed to obtain the titanium-containing active brazing filler metal strip.

[0020] In one optional embodiment, the melting temperature in step 1 is 1000~1200℃.

[0021] In one optional embodiment, in step 2, the homogenization annealing temperature is 680~700℃ (below the solidus temperature of the alloy) and the time is 10~24 hours.

[0022] In one alternative embodiment, in step 2, after homogenization annealing, the surface of the ingot is milled or peeled to remove the surface oxide layer and defects.

[0023] In one optional embodiment, in step 3, hot rolling can be selectively performed before the first cold rolling, with the hot rolling temperature being 650~750℃.

[0024] In an optional implementation, in step 3, when the Ti content in the brazing strip is greater than 4%, the single-pass reduction rate is controlled at 3% to 6%.

[0025] In one optional implementation, in step 3, the condition for vacuum intermediate annealing is: a vacuum level lower than 1 × 10⁻⁶. -3Pa, annealing temperature is 600~700℃, holding time is 30~60 minutes, to eliminate residual stress, soften the strip, and ensure that the strip has good flexibility during use.

[0026] In one optional embodiment, in step 4, the vacuum annealing temperature of the finished product is 550~650℃, and the holding time is 20~40 minutes.

[0027] In another aspect, the present invention provides a metal connection material comprising the titanium-containing active brazing strip as described above.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) Solved the problem of processing cracking: By improving the original structure through "homogenization annealing" and the rolling strategy of "multi-pass, small reduction rate", the edge cracking and strip breakage problem of high Ti content active brazing filler metal during the rolling process can be effectively avoided, and the yield can reach more than 85%.

[0030] (2) The preparation of thin strip material has been realized: The method of the present invention can stably prepare thin strip material with a thickness of 50~200 micrometers and a width of up to 100mm, which meets the stringent requirements of precision brazing for the shape of the brazing filler metal.

[0031] (3) The activity and surface quality of the brazing filler metal are guaranteed: the entire melting and heat treatment process is carried out under high vacuum, which effectively prevents the oxidation and contamination of the active element Ti, ensuring that the surface of the strip is smooth and free of oxide scale, and maximizing the brazing performance of the brazing filler metal.

[0032] (4) Good process controllability and repeatability: This invention provides a complete and clear set of process parameter windows, providing a reliable technical path for the industrial mass production of high-quality multi-element titanium-containing active brazing wire strip. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation route of the titanium-containing active solder strip of the present invention.

[0034] Figure 2 The image shows the result of butt welding Al2O3 with the strip prepared in Example 1. Detailed Implementation

[0035] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0038] Example 1

[0039] A titanium-containing active solder strip comprises the following chemical composition by mass percentage: Ti 2.0%, Ni 1.0%, Cu 28.0%, with the balance being Ag. Sn is not added in this embodiment.

[0040] The formulation of the titanium-containing active solder strip in this embodiment is a basic verification formulation. A relatively low Ti content (2.0%) is selected to ensure basic activity while controlling the total amount of brittle phase formation. The Ni content is set at the upper limit of the claims (1.0%) to improve microstructure and plasticity through Ni. The Cu content is close to the Ag-Cu eutectic point, which can form a matrix with good plasticity, providing favorable conditions for plastic processing.

[0041] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0042] (1) High vacuum melting: After weighing Ag, Cu, Ti and Ni raw materials with a purity of not less than 99.9% according to the designed composition, place them in a vacuum induction melting furnace and evacuate to 2×10 -3 Pa, heated to 1100℃ to melt and electromagnetically stirred for 15 minutes, then cast into an alloy ingot 20mm thick.

[0043] (2) Homogenization annealing: The alloy ingot is subjected to a vacuum degree of 5×10 -3 In a Pa annealing furnace, the temperature is raised to 700℃ and held for 12 hours, then cooled in the furnace. After cooling, the surface of the alloy ingot is milled to remove approximately 0.5 mm of surface layer.

[0044] (3) "Multi-pass, low reduction" plastic processing and intermediate annealing: A four-roll cold rolling mill is used for rolling, and the single-pass reduction is controlled at about 8%. Whenever the total deformation reaches about 40%, a vacuum intermediate annealing is performed. The annealing conditions are: vacuum degree 8×10 -4 Pa, temperature 650℃, hold for 40 minutes. Repeat this process 8 times.

[0045] (4) Finished product rolling and annealing: The strip is precision rolled to a thickness of 100μm and a width of 50mm, and then vacuum annealed at 600℃ for 30 minutes. Finally, a bright, crack-free, and flexible active brazing filler metal strip is obtained.

[0046] Example 2

[0047] A titanium-containing active solder strip, comprising the following chemical composition by mass percentage: Ti 3.5%, Sn 2.0%, Ni 0.8%, Cu 25.0%, with the balance being Ag.

[0048] The titanium-containing active brazing alloy strip formulation in this embodiment is a comprehensive performance optimization formulation. The Ti content is increased to a moderate level (3.5%) to enhance brazing activity. 2.0% Sn is introduced to lower the alloy melting point, improve fluidity, and enhance brazing processability. The Ni content (0.8%) works synergistically with Ti to further improve processing performance. The Cu content is adjusted accordingly to balance the alloy's melting characteristics.

[0049] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0050] (1) High vacuum melting: The melting temperature is 1050℃, and the rest of the process is the same as in Example 1.

[0051] (2) Homogenization annealing: The alloy ingot is vacuum held at 680℃ for 18 hours and then cooled in the furnace.

[0052] (3) "Multi-pass, low reduction rate" plastic processing and intermediate annealing: The alloy ingot is first hot-rolled at 700℃ to form a 5mm thick plate. Then, it is cold-rolled, with the single-pass reduction rate controlled at 6%. Whenever the total deformation reaches approximately 35%, a vacuum intermediate annealing is performed under the following conditions: vacuum degree 5×10⁻⁶. -4 Pa, temperature 680℃, hold for 35 minutes. Repeat this process 10 times.

[0053] (4) Finished product rolling and annealing: The strip is precision rolled to a thickness of 80 μm and a width of 80 mm, and then vacuum annealed at 620 °C for 25 minutes. Finally, a smooth surface and uniform size active brazing filler metal strip is obtained.

[0054] Example 3

[0055] A titanium-containing active solder strip, comprising the following chemical composition by mass percentage: Ti 4.8%, Sn 1.0%, Ni 0.5%, Cu 22.0%, with the balance being Ag.

[0056] The titanium-containing active brazing filler metal strip formulation in this embodiment is a challenging formulation with high activity and high processing difficulty. The Ti content is close to the upper limit of the claim scope (4.8%) to meet the most stringent brazing activity requirements, but this also brings the most severe brittleness problem. To address this, a more stringent processing technique is employed. The addition of 0.5% Ni and 1.0% Sn, and the reduction of Cu content to 22%, aims to slightly alleviate brittleness from a compositional perspective and improve the final brazing performance.

[0057] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0058] (1) High vacuum melting: The melting temperature is 1150℃, and the rest of the process is the same as in Example 1.

[0059] (2) Homogenization annealing: The ingot is vacuum-heated at 680°C for 24 hours to dissolve and disperse the brittle phase to the maximum extent.

[0060] (3) "Multi-pass, low reduction rate" plastic processing and intermediate annealing: Due to the high Ti content and brittleness, a smaller single-pass reduction rate is adopted, controlled at 4%~5%. Vacuum intermediate annealing is performed whenever the total deformation reaches 30%, and the annealing conditions are: vacuum degree 2×10 -4 Pa, temperature 700℃, hold for 50 minutes. Increase the number of cycles accordingly to 15.

[0061] (4) Finished product rolling and annealing: The strip was precision rolled to a thickness of 150 μm and a width of 30 mm, and then vacuum annealed at 580 °C for 40 minutes. The obtained active brazing filler metal strip had no visible microcracks, proving that this process is also effective for highly brittle materials.

[0062] Example 4

[0063] A titanium-containing active solder strip, comprising the following chemical composition by mass percentage: Ti 3.0%, Sn 4.5%, Ni 0.9%, Cu 26.0%, with the balance being Ag.

[0064] In the formulation of the titanium-containing active brazing filler metal strip in this embodiment, the Ti content is moderate (3.0%) and the Ni content is relatively high (0.9%) to ensure good basic plasticity. The Sn content is close to the upper limit (4.5%), which significantly reduces the fluidity of the brazing filler metal while ensuring machinability, and improves its ability to fill and spread in precise micro-weld seams, making it particularly suitable for applications with extreme requirements for weld gaps.

[0065] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0066] (1) High vacuum melting: Same as Example 2.

[0067] (2) Homogenization annealing: Same as in Example 2.

[0068] (3) "Multi-pass, low reduction rate" plastic processing and intermediate annealing: The process is similar to that in Example 2, but the number of "cold rolling-annealing" cycles is increased to achieve a thinner thickness. The single-pass reduction rate is controlled at 5%, and a total of 18 intermediate annealing cycles are performed.

[0069] (4) Finished product rolling and annealing: The strip was precision rolled to a thickness of 50 μm and a width of 60 mm, and then vacuum annealed at 580 °C for 20 minutes. Ultra-thin and complete active brazing filler metal strips were obtained, which are suitable for applications with extreme requirements for brazing gap.

[0070] Example 5

[0071] A titanium-containing active solder strip comprises, by mass percentage, the following chemical composition: Ti 2.5%, Ni 0.6%, Cu 30.0%, with the balance being Ag. Sn is not added in this embodiment.

[0072] The formulation of the titanium-containing active solder strip in this embodiment is designed for the preparation of wide strip (100 mm). Wide-width rolling places higher demands on the uniformity of the material and its resistance to edge cracking than narrow strip rolling.

[0073] A relatively low Ti content (2.5%) is used to fundamentally reduce the amount of brittle phases. A Cu content at the upper limit of the claims (30.0%) is used to form a larger amount of well-ductile Ag-Cu eutectic matrix, thereby improving the overall ductility of the material. 0.6% Ni is added to refine the grains, ensuring uniform stress distribution within the material during wide-width rolling, enhancing resistance to transverse tensile stress, and effectively suppressing edge cracking.

[0074] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0075] (1) High vacuum melting: cast into alloy ingots with a width of 120 mm and a thickness of 25 mm. The remaining processes are the same as in Example 1.

[0076] (2) Homogenization annealing: Same as in Example 1.

[0077] (3) "Multi-pass, low reduction rate" plastic processing and intermediate annealing: Wide-width rolling mill is used for rolling. In order to ensure uniform thickness along the width direction, the single-pass reduction rate is controlled within a small range of 3% to 5%. The intermediate annealing conditions are the same as in Example 1.

[0078] (4) Finished product rolling and annealing: The strip is precision rolled to a width of 100 mm and a thickness of 200 μm. Then, the finished product is vacuum annealed at 630 °C for 35 minutes. The finished product has good surface quality and a thickness tolerance within ±5 μm, which meets the requirements for large-area brazing.

[0079] Example 6

[0080] A titanium-containing active solder strip comprises the following chemical composition by mass percentage: Ti 3.0%, Sn 3.0%, Cu 27.0%, with the balance being Ag. Ni is not added in this embodiment.

[0081] The formulation of the titanium-containing active solder strip in this embodiment is primarily to verify that titanium-containing active solder strip can be successfully prepared using only the special processing technology of this invention, without the addition of Ni (Ni=0). A moderate Ti content (3.0%) was chosen, which presents a processing challenge in the absence of Ni. 3.0% Sn was added to lower the melting point and improve brazing fluidity. The Cu content (27.0%) was maintained at a high level to provide good basic plasticity for the material, partially compensating for any potential loss in processing performance due to the lack of Ni.

[0082] The preparation method of the titanium-containing active solder strip in this embodiment includes the following steps:

[0083] (1) High vacuum melting: The melting temperature is 1080℃, and the rest of the process is the same as in Example 1.

[0084] (2) Homogenization annealing: The ingot is vacuum-heated at 700°C for 20 hours to fully improve the microstructure of the as-cast alloy.

[0085] (3) "Multi-pass, low reduction rate" plastic processing and intermediate annealing: The single-pass reduction rate is controlled at 5%~7%, and vacuum intermediate annealing is performed when the total deformation reaches 30%~35%. Annealing conditions are: vacuum degree 6×10 -4 Pa, temperature 660℃, hold for 45 minutes. Repeat this cycle 12 times.

[0086] (4) Finished product rolling and annealing: The strip was precision rolled to a thickness of 120 μm and a width of 70 mm, and then vacuum annealed at 610 °C for 30 minutes. The results show that even without Ni, crack-free and high-performance active solder strips can still be obtained by strictly controlling the processing and heat treatment process described in this invention.

[0087] The above description is only for better explaining the embodiments of the present invention and is not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. A titanium-containing active solder strip, characterized in that, The chemical composition, by mass percentage, includes the following: Ti: 1.5-5%, Sn: 0-5%, Ni: 0-1%, Cu: 20-30%, with the balance being Ag.

2. A method for preparing titanium-containing active solder strip as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh the Ag, Cu, Ti, Sn, and Ni raw materials according to the designed composition, and then heat them under a vacuum of less than 5 × 10⁻⁶. -3 The alloy ingot was obtained by smelting under the condition of Pa. Step 2: Perform homogenization annealing on the alloy ingot; Step 3: Perform multi-pass cold rolling on the homogenized annealed alloy ingot, with the single-pass reduction rate controlled within 10%; when the total processing deformation reaches 30%~50%, perform a vacuum intermediate annealing to achieve recrystallization and restore plasticity; repeat the cycle of cold rolling and vacuum intermediate annealing until the strip thickness is close to the target size. Step 4: The strip is precision rolled to a thickness of 50-200 micrometers, and then vacuum annealed to obtain the titanium-containing active solder strip.

3. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 1, the melting temperature is 1000~1200℃.

4. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 2, the homogenization annealing temperature is 680~700℃ and the time is 10~24 hours.

5. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 2, after homogenization annealing, the surface of the ingot is milled or peeled.

6. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 3, before the first cold rolling, hot rolling can be selectively performed, with a hot rolling temperature of 650~750℃.

7. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 3, when the Ti content in the brazing strip is greater than 4%, the single-pass reduction rate is controlled at 3% to 6%.

8. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 3, the conditions for vacuum intermediate annealing are: a vacuum level lower than 1×10⁻⁶. -3 Pa, annealing temperature is 600~700℃, holding time is 30~60 minutes.

9. The method for preparing titanium-containing active solder strip according to claim 2, characterized in that, In step 4, the temperature of vacuum annealing of the finished product is 550~650℃, and the holding time is 20~40 minutes.

10. A metallic connecting material, characterized in that, Includes the titanium-containing active solder strip as described in claim 1.

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