Creep-resistant bi-in-sn fusible alloy foil and preparation method and application thereof

Abstract

This invention discloses an anti-creep Bi-In-Sn fusible alloy foil, comprising an inner alloy sheet and a metal fiber mesh covering the surface of the alloy sheet, wherein the alloy sheet is a Bi-In-Sn alloy. The anti-creep Bi-In-Sn fusible alloy foil of this invention employs a metal fiber mesh coating on the fusible alloy to: 1) secure the fusible alloy sheet, suppressing the risk of cracking during subsequent rolling and improving the yield of the foil alloy; 2) enhance the strength and toughness of the alloy foil body, making it less prone to cracking during use and transportation; and 3) when brazing brass temperature control components, the metal fiber mesh partially dissolves into the brazing seam, playing a solid solution strengthening role and delaying the high-temperature creep of the component to a certain extent; simultaneously, the unmelted metal fiber mesh in the brazing seam acts as a pinning agent to prevent component deformation, significantly improving the creep resistance of the component.

Description

Technical Field

[0001] This invention relates to the field of brazing materials technology, specifically to an anti-creep Bi-In-Sn fusible alloy foil, a method for preparing the anti-creep Bi-In-Sn fusible alloy foil, and the application of the anti-creep Bi-In-Sn fusible alloy foil in brazing brass components. Background Technology

[0002] Bi-In-Sn fusible alloy is a lead-free solder with a low melting temperature, approximately between 85 and 90°C. It has good flow and wetting properties and has unique applications in the automotive, aerospace, electrical instrumentation, and light industry sectors.

[0003] However, because the Bi-In-Sn fusible alloy is mainly composed of a large number of brittle phases, such as BiIn and InSn4 phases, the solder is brittle and has low strength. Therefore, the machinability of this fusible alloy is poor, and it is difficult to produce foil or sheet forms using conventional methods, thus limiting its applications. In particular, when this fusible alloy is used for brazing brass temperature control components, its poor high-temperature reliability easily leads to creep failure of the components.

[0004] To address the aforementioned shortcomings, it is necessary to develop a creep-resistant Bi-In-Sn fusible alloy foil that can improve both the inherent strength and toughness of the alloy foil, as well as the strength and high-temperature service reliability of the brazed joints in brass temperature control components. Summary of the Invention

[0005] In view of this, in order to overcome the defects of the prior art and achieve the above-mentioned objectives, the present invention provides a creep-resistant Bi-In-Sn fusible alloy foil.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An anti-creep Bi-In-Sn fusible alloy foil includes an inner alloy sheet and a metal fiber mesh covering a portion of the surface of the alloy sheet. The alloy sheet is a Bi-In-Sn alloy. That is, the anti-creep Bi-In-Sn fusible alloy foil has a three-layer sandwich structure, with the inner layer being a Bi-In-Sn alloy and the outer two sides covered by metal fiber mesh.

[0008] According to some preferred embodiments of the present invention, the metal fiber mesh is formed by fibers wound around the surface of the alloy sheet, and the spacing between adjacent fibers is 3-5 mm.

[0009] According to some preferred embodiments of the present invention, the diameter of the fiber is 100 to 500 μm.

[0010] According to some preferred embodiments of the invention, the filaments are made of one or more of silver, nickel, or copper.

[0011] According to some preferred embodiments of the present invention, the mass fractions of each element in the Bi-In-Sn alloy are: Bi 56-60 parts, In 25-28 parts, Sn 12-15 parts, and RE 0.1-0.5 parts. The addition of an appropriate amount of RE (mixed rare earth) element to the Bi-In-Sn alloy helps to purify grain boundaries and refine the microstructure, further improving the strength and toughness of the solder body.

[0012] According to some preferred embodiments of the invention, the RE is one or more of Ce, Sc, and Nd.

[0013] According to some preferred embodiments of the present invention, the fusible alloy foil is formed by winding and rolling fibers around an alloy plate, wherein the alloy plate forms an alloy sheet and the fibers form a metal fiber mesh.

[0014] According to some preferred embodiments of the present invention, the thickness of the alloy plate before rolling is 1.5 to 2 mm, and the thickness of the fusible alloy foil formed after rolling is 0.1 to 0.5 mm. That is, the rolled fusible alloy is in foil form.

[0015] According to some preferred embodiments of the invention, after rolling, the surface of the alloy sheet has grooves for accommodating the metal fiber mesh, the metal fiber mesh being located in the grooves.

[0016] According to some preferred embodiments of the invention, after rolling, the surface of the metal fiber mesh is flush with the surface of the alloy sheet.

[0017] The present invention also provides a method for preparing the above-mentioned creep-resistant Bi-In-Sn fusible alloy foil, comprising the following steps:

[0018] On the outer surface of the alloy plate, fibers are wound and wrapped at equal intervals along its length; rolled to the finished thickness, the alloy plate forms an alloy sheet, and the fibers form a metal fiber mesh, to obtain a creep-resistant Bi-In-Sn fusible alloy foil.

[0019] According to some preferred embodiments of the invention, during rolling, the alloy plate with fibers wound around its surface is immersed in an oil bath at a temperature of 50–70°C.

[0020] According to some preferred embodiments of the present invention, the alloy plate is prepared by the following steps: heating and melting Bi-In-Sn alloy raw materials into molten metal; injecting the molten metal into a mold cavity, and obtaining the alloy plate after cooling and demolding.

[0021] According to some preferred embodiments of the present invention, the surface of the mold cavity is coated with a release oil, which is one or more of soybean oil, peanut oil, and rapeseed oil.

[0022] Specifically, in some embodiments of the present invention, the preparation method of the creep-resistant Bi-In-Sn fusible alloy foil includes the following steps:

[0023] Step 1: Prepare Bi-In-Sn alloy raw materials according to the mass proportions, place the raw materials inside the graphite crucible of the high-frequency induction welding machine, heat to 90-150℃, and melt into molten metal for later use.

[0024] Step 2: First, evenly brush the release oil onto the inner surface of the graphite mold, then assemble and fix it. The release oil can be one or more of soybean oil, peanut oil, and rapeseed oil.

[0025] Step 3: Inject the molten metal from Step 1 into the graphite mold cavity assembled in Step 2. After cooling and demolding, an alloy plate with a thickness of 1.5-2mm is obtained.

[0026] Step 4: Wind and cover the alloy plate from Step 3 with metal fibers at equal intervals (3-5mm) along its length. Then, use a rolling mill, placing both the rolls and the brazing filler plate (alloy plate) in an oil bath at a temperature of 50-70℃, to roll to the finished thickness to obtain a creep-resistant fusible alloy foil.

[0027] The present invention also provides an application of the above-mentioned creep-resistant Bi-In-Sn fusible alloy foil in brazing of brass components.

[0028] Due to the adoption of the above technical solutions, the advantages of this invention compared to the prior art are as follows: The anti-creep Bi-In-Sn fusible alloy foil of this invention uses a metal fiber mesh wrapped around the fusible alloy. Firstly, this secures the fusible alloy plate, suppressing the risk of cracking of the alloy plate during subsequent rolling and improving the yield of the foil alloy. Secondly, the metal fiber mesh enhances the strength and toughness of the alloy foil body, making it less prone to cracking during use and transportation. Thirdly, when brazing brass temperature control components, the metal fiber mesh partially dissolves into the brazing seam, playing a solid solution strengthening role and delaying the high-temperature creep of the component to a certain extent. At the same time, the unmelted metal fiber mesh in the brazing seam acts as a pinning agent for component deformation, significantly improving the creep resistance of the component. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the cross-sectional structure of the anti-creep Bi-In-Sn fusible alloy foil in a preferred embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the alloy plate with externally wound fiber filaments in a preferred embodiment of the present invention (before rolling);

[0032] Figure 3 This is an enlarged view (after rolling) of the creep-resistant Bi-In-Sn fusible alloy foil in a preferred embodiment of the present invention;

[0033] Figure 4 This is a photograph of the morphology of the alloy foil brazed brass joint shear sample prepared in Experimental Example 2 of this invention;

[0034] Figure 5 This is a photograph of the brass temperature control component prepared in Experimental Example 3 of the present invention.

[0035] In the attached diagram, 1-metal fiber mesh, 2-alloy sheet. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] The creep-resistant Bi-In-Sn fusible alloy foil of the present invention can improve both the inherent strength and toughness of the alloy foil, and enhance the strength and high-temperature service reliability of the brazed joints in brass temperature control components. Furthermore, a method for preparing this alloy foil is provided, enabling the fabrication of the Bi-In-Sn fusible alloy foil. Details are as follows:

[0038] The creep-resistant Bi-In-Sn fusible alloy foil of this embodiment includes an alloy sheet 2 (solder filler metal) located inside and a metal fiber mesh 1 covering the surface of the alloy sheet. The alloy sheet is a Bi-In-Sn alloy. The mass fractions of each element in the Bi-In-Sn alloy are: Bi 56-60 parts, In 25-28 parts, Sn 12-15 parts, and RE 0.1-0.5 parts. RE is one or more of Ce, Sc, and Nd. The addition of an appropriate amount of RE element to the Bi-In-Sn alloy plays a role in purifying grain boundaries and refining the microstructure, further improving the strength and toughness of the solder body.

[0039] In this embodiment, the creep-resistant Bi-In-Sn fusible alloy foil has a three-layer sandwich structure, with the inner layer being a Bi-In-Sn alloy and the outer two sides partially covered by a metal fiber mesh.

[0040] The metal fiber mesh is formed by fibers wound around the surface of an alloy sheet, with a spacing of 3-5 mm between adjacent fibers. The diameter of the fibers is 100-500 μm. The fibers are made of one or more of silver, nickel, or copper.

[0041] The fusible alloy foil is formed by winding and rolling fibers around an alloy sheet, resulting in an alloy sheet and a metal fiber mesh. Before rolling, the alloy sheet is 1.5–2 mm thick, and after rolling, the fusible alloy foil is 0.1–0.5 mm thick. That is, the rolled fusible alloy is in foil form. After rolling, the surface of the alloy sheet has grooves to accommodate the metal fiber mesh, which is located within these grooves. After rolling, the surface of the metal fiber mesh is flush with the surface of the alloy sheet.

[0042] The method for preparing the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment includes the following steps:

[0043] Step 1: Prepare Bi-In-Sn alloy raw materials according to the mass proportions, place the raw materials inside the graphite crucible of the high-frequency induction welding machine, heat to 90-150℃, and melt into molten metal for later use.

[0044] Step 2: Apply the release oil evenly to the inner surface of the graphite mold, then assemble and fix it. The release oil can be one or more of soybean oil, peanut oil, and rapeseed oil.

[0045] Step 3: Inject the molten metal from Step 1 into the graphite mold cavity assembled in Step 2. After cooling and demolding, an alloy plate with a thickness of 1.5-2mm is obtained.

[0046] Step 4: The alloy plate from Step 3 is wound and covered with metal fibers at equal intervals (3-5mm) along its length. Then, a rolling mill is used, with both the rolls and the brazing plate (alloy plate) placed in an oil bath at a temperature of 50-70℃, to roll to the finished thickness. The alloy plate forms an alloy sheet, and the fiber filaments form a metal fiber mesh, thus obtaining a creep-resistant Bi-In-Sn fusible alloy foil.

[0047] Example 1

[0048] The creep-resistant Bi-In-Sn fusible alloy foil of this embodiment includes an inner alloy sheet (solder metal) and a metal fiber mesh covering the surface of the alloy sheet. The alloy sheet is a Bi-In-Sn alloy. The mass fractions of each element in the Bi-In-Sn alloy are: Bi 56 parts, In 25 parts, Sn 12 parts, and RE 0.1 parts. RE is Ce. The addition of an appropriate amount of RE element to the Bi-In-Sn alloy helps to purify grain boundaries and refine the microstructure, further improving the strength and toughness of the solder body.

[0049] In this embodiment, the creep-resistant Bi-In-Sn fusible alloy foil has a three-layer sandwich structure, with the inner layer being a Bi-In-Sn alloy and the outer two sides covered by a metal fiber mesh.

[0050] The metal fiber mesh is formed by fibers wound around the surface of an alloy sheet, with a spacing of 3 mm between adjacent fibers. The diameter of the fibers is 100 μm. The fibers are made of silver.

[0051] The fusible alloy foil is formed by winding and rolling fibers around an alloy sheet, resulting in an alloy sheet and a metal fiber mesh. Before rolling, the alloy sheet is 1.5 mm thick, and after rolling, the fusible alloy foil is 0.1 mm thick. That is, the rolled fusible alloy is in foil form. After rolling, the surface of the alloy sheet has grooves to accommodate the metal fiber mesh, which is located within these grooves. After rolling, the surface of the metal fiber mesh is flush with the surface of the alloy sheet.

[0052] The method for preparing the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment includes the following steps:

[0053] Step 1: Prepare Bi-In-Sn alloy raw materials according to the mass proportions, place the raw materials inside the graphite crucible of the high-frequency induction welding machine, heat to 90℃, and melt into molten metal for later use.

[0054] Step 2: First, evenly brush the release oil onto the inner surface of the graphite mold, then assemble and fix it. The release oil is soybean oil.

[0055] Step 3: Inject the molten metal from Step 1 into the graphite mold cavity assembled in Step 2. After cooling and demolding, a 1.5mm thick alloy plate is obtained.

[0056] Step 4: The alloy plate from Step 3 is wound and covered with metal fibers at equal intervals (3mm) along its length. Then, a rolling mill is used, with both the rolls and the brazing plate (alloy plate) placed in an oil bath at 50°C, to roll to the finished thickness. The alloy plate forms an alloy sheet, and the fiber filaments form a metal fiber mesh, thus obtaining a creep-resistant Bi-In-Sn fusible alloy foil.

[0057] Example 2

[0058] The structure and preparation method of the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment are basically the same as those in Example 1, with the following differences:

[0059] In this embodiment, the mass fractions of each element in the anti-creep Bi-In-Sn fusible alloy foil (brazing filler metal) are: Bi57, In26, Sn13, RE 0.2; RE is Sc.

[0060] The fibers are made of nickel, with a spacing of 3.5 mm between adjacent fibers. The diameter of the fibers is 200 μm. The thickness of the alloy plate before rolling is 1.6 mm, and the thickness of the fusible alloy foil formed after rolling is 0.2 mm.

[0061] The temperature at which the Bi-In-Sn alloy raw material is heated to melt into a liquid metal is 100℃; the release oil is peanut oil; and the oil bath temperature during rolling is 60℃.

[0062] Example 3

[0063] The structure and preparation method of the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment are basically the same as those in Example 1, with the following differences:

[0064] In this embodiment, the mass fractions of each element in the alloy sheet (brazing filler metal) of the creep-resistant Bi-In-Sn fusible alloy foil are: Bi58, In27, Sn14, RE 0.3; RE is Nd.

[0065] The fiber filaments are made of copper, with a spacing of 4 mm between adjacent filaments. The diameter of the fiber filaments is 300 μm. The thickness of the alloy plate before rolling is 1.8 mm, and the thickness of the fusible alloy foil formed after rolling is 0.3 mm.

[0066] The temperature at which the Bi-In-Sn alloy raw material is heated to melt into a liquid metal is 110℃; the release oil is rapeseed oil; and the oil bath temperature during rolling is 65℃.

[0067] Example 4

[0068] The structure and preparation method of the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment are basically the same as those in Example 1, with the following differences:

[0069] In this embodiment, the mass fractions of each element in the alloy sheet (brazing filler metal) of the creep-resistant Bi-In-Sn fusible alloy foil are: Bi59, In28, Sn15, RE 0.4; RE is Ce.

[0070] The fiber material is silver, and the spacing between adjacent fibers is 4.5 mm. The diameter of the fiber is 400 μm. The thickness of the alloy plate before rolling is 1.9 mm, and the thickness of the fusible alloy foil formed after rolling is 0.4 mm.

[0071] The temperature at which the Bi-In-Sn alloy raw material is heated to melt into a liquid metal is 120℃; the release oil is soybean oil; and the oil bath temperature during rolling is 70℃.

[0072] Example 5

[0073] The structure and preparation method of the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment are basically the same as those in Example 1, with the following differences:

[0074] In this embodiment, the mass fractions of each element in the alloy sheet (brazing filler metal) of the creep-resistant Bi-In-Sn fusible alloy foil are: Bi60, In28, Sn15, RE 0.5; RE is Ce.

[0075] The fiber material is silver, and the spacing between adjacent fibers is 5mm. The diameter of the fiber is 500um. The thickness of the alloy plate before rolling is 2mm, and the thickness of the fusible alloy foil formed after rolling is 0.5mm.

[0076] The temperature at which the Bi-In-Sn alloy raw material is heated to melt into a liquid metal is 130℃; the release oil is soybean oil; and the oil bath temperature during rolling is 70℃.

[0077] Example 6

[0078] The structure and preparation method of the creep-resistant Bi-In-Sn fusible alloy foil in this embodiment are basically the same as those in Example 1, with the following differences:

[0079] In this embodiment, the mass fractions of each element in the anti-creep Bi-In-Sn fusible alloy foil (brazing filler metal) are: Bi60, In28, Sn15, RE 0.5; RE is Sc.

[0080] The fibers are made of nickel, with a spacing of 5 mm between adjacent fibers. The diameter of the fibers is 500 μm. The thickness of the alloy plate before rolling is 2 mm, and the thickness of the fusible alloy foil formed after rolling is 0.5 mm.

[0081] The temperature at which the Bi-In-Sn alloy raw material is heated to melt into a liquid metal is 150℃; the release oil is soybean oil; and the oil bath temperature during rolling is 70℃.

[0082] Comparative Example 1

[0083] In this comparative example, the Bi-In-Sn fusible alloy foil only has an internal alloy sheet similar to that in Example 1, without the metal fiber mesh covering the outer surface of the alloy sheet. The composition and preparation method of the alloy sheet are basically the same as in Example 1.

[0084] Comparative Example 2

[0085] The structure and preparation method of the Bi-In-Sn fusible alloy foil in this comparative example are basically the same as those in Example 1, except that the Bi-In-Sn alloy in the Bi-In-Sn fusible alloy foil of this comparative example does not contain RE components.

[0086] Comparative Example 3

[0087] The structure and preparation method of the Bi-In-Sn fusible alloy foil in this comparative example are basically the same as those in Example 1. The difference is that the spacing between adjacent fibers of the metal fiber mesh on the Bi-In-Sn fusible alloy foil in this comparative example is greater than 5 mm, and is 8 mm.

[0088] Comparative Example 4

[0089] The structure and preparation method of the Bi-In-Sn fusible alloy foil in this comparative example are basically the same as those in Example 1. The difference is that the spacing between adjacent fibers of the metal fiber mesh on the Bi-In-Sn fusible alloy foil in this comparative example is less than 3 mm, and is 1 mm.

[0090] Tests and Results

[0091] Experimental Example 1

[0092] To examine and compare the forming performance of the alloy foils in Examples 1-6 and Comparative Examples 1-4 of the present invention, 1 kg of brazing alloy foils were prepared according to the preparation methods in Examples 1-6 and Comparative Examples 1-4, respectively.

[0093] Comparative analysis revealed that Examples 1-6 yielded ideal creep-resistant fusible alloy foils with a yield rate exceeding 80%. Comparative Example 1, however, had a brittle composition, lacked external metal fiber binding and shaping during rolling, resulting in poor formability and the inability to obtain a brazing foil. Comparative Example 2 exhibited slightly better toughness and could yield a brazing foil, but the Bi-In-Sn alloy lacked RE components, leading to coarse grains and low strength in the brazing foil. Comparative Example 3, with its larger metal fiber spacing, yielded an alloy foil, but with a low yield rate of approximately 35%. Comparative Example 4 yielded a brazing foil, but the denser arrangement of metal fibers on the outside affected the brazing joint performance; the dense fiber web and high fiber ratio resulted in a lower proportion of fusible alloy components, hindering effective brazing.

[0094] Experiment Example 2

[0095] To examine and compare the shear strength of brazed brass joints with alloy foil in Examples 1-6 and Comparative Examples 1-4 of the present invention, induction brazing tests were conducted on brass plates using 10 kinds of brazing alloy foils from Examples 1-6 and Comparative Examples 1-4. Then, the shear strength test of the joints was conducted according to the requirements of GB / T 11363. The test results are shown in Table 1 below.

[0096] Table 1 Shear strength of brass plate joints

[0097] Types of brazing filler metal Average shear strength of joint / MPa Example 1 26.4 Example 2 27.8 Example 3 31.2 Example 4 27.5 Example 5 26.3 Example 6 24.9 Comparative Example 1 16.5 Comparative Example 2 18.8 Comparative Example 3 20.2 Comparative Example 4 10.5

[0098] The results in Table 1 show that, compared with Comparative Examples 1-4, the joint shear strength of the alloy foil brazed brass plates in the examples is significantly higher, especially in Example 3, where the joint shear strength is as high as 31.2 MPa.

[0099] Experimental Example 3

[0100] To examine and compare the high-temperature service performance of the alloy foil brazed brass temperature control components in Examples 1-6 and the comparative examples of the present invention, high-temperature tensile tests were conducted on different temperature control components in accordance with GB / T 11363 (test conditions: 45±2℃, load 1000±2N, hold for 5min). The tensile creep displacement of the components under the same conditions was measured, and the experimental results are shown in Table 2 below.

[0101] Table 2 Load-bearing tensile creep displacement of brass plate joints

[0102] Types of brazing filler metal Initial sample length (mm) Specimen length after 5 minutes of load holding / mm Creep displacement / mm Example 1 66.96 67.10 0.14 Example 2 68.78 68.90 0.12 Example 3 67.10 67.20 0.10 Example 4 66.60 66.60 0.00 Example 5 66.50 66.65 0.15 Example 6 66.80 66.89 0.09 Comparative Example 1 66.85 67.69 0.84 Comparative Example 2 66.90 67.55 0.65 Comparative Example 3 66.78 67.28 0.50 Comparative Example 4 68.80 70.00 1.20

[0103] The results in Table 2 show that the creep displacement of the temperature control components in Examples 1-6 during high-temperature service is much less than 0.5 mm, while the creep displacement of the temperature control components in Comparative Examples 1-4 is greater than or equal to 0.5 mm during high-temperature service. It can be seen that the brass temperature control components brazed with fusible alloy in the examples exhibit significantly better creep resistance.

[0104] This invention improves the strength and toughness of the Bi-In-Sn alloy foil by coating the surface of the alloy with a metal fiber mesh. Adding an appropriate amount of RE element purifies grain boundaries and refines the microstructure, further enhancing the strength and toughness of the solder. To obtain the solder foil, this invention uses metal fibers to bind the fusible alloy plate, followed by oil bath warm rolling to prepare the Bi-In-Sn fusible alloy foil with a high yield. Compared with existing technologies, the advantages of this invention are:

[0105] (1) The metal fiber mesh covered by the fusible alloy of the present invention has three advantages: First, it binds the fusible alloy plate, suppresses the risk of cracking of the alloy plate during subsequent rolling, and improves the yield of foil alloy; Second, the metal fiber mesh enhances the strength and toughness of the alloy foil body, making it less prone to cracking during use and transportation; Third, when brazing brass temperature control components, the metal fiber mesh will partially dissolve into the brazing seam, playing a solid solution strengthening role and delaying the high-temperature creep of the component to a certain extent; At the same time, the unmelted metal fiber mesh plays a role in pinning the deformation of the component in the brazing seam, significantly improving the creep resistance of the component;

[0106] (2) The Bi-In-Sn alloy in this invention contains trace amounts of Re, which plays a role in purifying grain boundaries and refining grains, further improving the strength and toughness of the alloy body and enhancing its creep resistance.

[0107] (3) The present invention achieves effective preparation of creep-resistant Bi-In-Sn fusible alloy foil through alloy plate casting, alloy plate winding with metal fiber for fixing, and oil bath warm rolling.

[0108] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A creep-resistant Bi-In-Sn fusible alloy foil, characterized in that, It has a three-layer sandwich structure, including an inner alloy sheet and a metal fiber mesh covering the surface of the alloy sheet. The alloy sheet is a Bi-In-Sn alloy. The metal fiber mesh is formed by fiber filaments wound on the surface of the alloy sheet, with a spacing of 3-5 mm between adjacent fiber filaments. The mass fractions of each element in the Bi-In-Sn alloy are: Bi 56-60 parts, In 25-28 parts, Sn 12-15 parts, and RE 0.1-0.5 parts. The fusible alloy foil is formed by winding fiber filaments around the alloy plate and rolling it. The alloy plate forms the alloy sheet, and the fiber filaments form the metal fiber mesh. During brazing, the metal fiber mesh will partially dissolve into the brazing seam.

2. The creep-resistant Bi-In-Sn fusible alloy foil according to claim 1, characterized in that, The diameter of the fiber is 100–500 μm.

3. The creep-resistant Bi-In-Sn fusible alloy foil according to claim 1, characterized in that, The fiber filaments are made of one or more of silver, nickel, or copper.

4. The creep-resistant Bi-In-Sn fusible alloy foil according to claim 1, characterized in that, The RE is one or more of Ce, Sc, and Nd.

5. The creep-resistant Bi-In-Sn fusible alloy foil according to claim 1, characterized in that, The thickness of the alloy plate before rolling is 1.5 to 2 mm, and the thickness of the fusible alloy foil formed after rolling is 0.1 to 0.5 mm.

6. The creep-resistant Bi-In-Sn fusible alloy foil according to claim 5, characterized in that, After rolling, the surface of the alloy sheet has a groove for accommodating the metal fiber mesh, and the metal fiber mesh is located in the groove; after rolling, the surface of the metal fiber mesh is flush with the surface of the alloy sheet.

7. A method for preparing a creep-resistant Bi-In-Sn fusible alloy foil as described in any one of claims 1-6, characterized in that, The process includes the following steps: winding and covering fibers at equal intervals along the length of the outer surface of the Bi-In-Sn alloy plate; rolling to the finished thickness, the alloy plate forms an alloy sheet, and the fibers form a metal fiber mesh to obtain a creep-resistant Bi-In-Sn fusible alloy foil; during rolling, the alloy plate with fibers wound on its surface is immersed in an oil bath at a temperature of 50-70°C.

8. The preparation method according to claim 7, characterized in that, The alloy plate is prepared by the following steps: heating and melting Bi-In-Sn alloy raw materials into molten metal; injecting the molten metal into a mold cavity, and obtaining the alloy plate after cooling and demolding.

9. The preparation method according to claim 8, characterized in that, The surface of the mold cavity is coated with release oil, which is one or more of soybean oil, peanut oil, and rapeseed oil.

10. The application of the creep-resistant Bi-In-Sn fusible alloy foil as described in any one of claims 1-6 in the brazing of brass components.

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