Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic brazing filler metal and preparation method and application thereof

Abstract

The invention relates to the technical field of welding, in particular to Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic brazing filler metal as well as a preparation method and application of the Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic brazing filler metal. The brazing filler metal is prepared from the following components in percentage by atom: 54 percent to 63 percent of Ag, 16.5 percent to 19.5 percent of Cu, 5.5 percent to 12.5 percent of Al, 7.5 percent to 14.5 percent of Sn, 1.0 percent to 2.5 percent of Y and 1.0 percent to 1.7 percent of Sc. The Al, Cu, Sn, Y and Sc elements are added into the Ag-based brazing filler metal, the thermal expansion coefficient of the brazing filler metal can be adjusted, the brazing filler metal can be better matched with titanium alloy and ceramic, and residual stress caused by thermal mismatch is reduced; the brazing filler metal has good wettability to titanium alloy and ceramic, and spreading and combination of the brazing filler metal on the surfaces of the titanium alloy and the ceramic are facilitated; when the material is used for brazing of ceramic and titanium alloy, the shear strength of a joint can reach 289 MPa.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, and in particular to an Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic solder and a preparation method and application thereof. Background Art

[0002] Titanium alloy is a metal material with excellent properties. It has low density, high strength, good corrosion resistance and high temperature resistance, strong anti-damping properties, and is non-magnetic and non-toxic. Therefore, it is widely used in aerospace, shipbuilding, medical equipment and other fields. In engineering applications, titanium alloys often need to be surface treated to improve their wear resistance. Therefore, welding ceramic materials to the surface of titanium alloys is a new low-cost method. However, there are significant differences in the elastic modulus and thermal expansion coefficient between ceramics and titanium alloys. The thermal mismatch during the cooling process leads to large residual stress in the joint, which seriously affects the quality of the joint.

[0003] Ag-based solders have attracted more and more attention from technical professionals because their welding temperature is lower than the melting point of the metal and their negative impact on the performance of the base material is relatively small. Ag-based solders are brazing materials with silver or silver-based solid solutions as the main components. Traditional Ag-based solders are mostly binary or ternary alloys. Although they have good wettability, electrical conductivity, thermal conductivity, corrosion resistance and filling ability, due to the limitations of composition and structure, it is difficult to significantly improve their performance through simple composition adjustments. This limits the adaptability and flexibility of the solder in specific applications. In contrast, multi-principal eutectic Ag-based solders can achieve higher performance improvements and a wider range of applications by introducing more elements and more complex structures.

[0004] Therefore, the key issue that needs to be solved urgently is how to provide an Ag-based multi-principal element eutectic solder that can improve the brazing quality of titanium alloys and ceramics, so as to enhance the strength of the welding area and thus accelerate its widespread application in the field of titanium alloys.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The first objective of the present invention is to provide an Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder. Based on the design concept of multiple principal elements and eutectic composition, the addition of Al, Cu, Sn, Y, and Sc to the Ag-based solder adjusts the solder's thermal expansion coefficient to better match titanium alloys and ceramics, reducing residual stress caused by thermal mismatch. Furthermore, the solder exhibits good wettability to titanium alloys and ceramics, facilitating solder spreading and bonding on the surfaces of titanium alloys and ceramics. This solves the technical problem of high residual stress and low joint strength in conventional solders used to braze ceramics and titanium alloys.

[0007] The second object of the present invention is to provide a method for preparing the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder as described above.

[0008] The third object of the present invention is to provide an application of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder as described above in welding titanium alloys and ceramics.

[0009] A fourth object of the present invention is to provide a method for preparing a ceramic and titanium alloy welded joint.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0011] An Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder comprises the following components, calculated by atomic percentage: 54%-63% of Ag, 16.5%-19.5% of Cu, 5.5%-12.5% ​​of Al, 7.5%-14.5% of Sn, 1.0%-2.5% of Y, and 1.0%-1.7% of Sc.

[0012] Preferably, the atomic content ratio of the Y to the Sc is 1-2.5:1.

[0013] Preferably, the solder is in powder form, and the average particle size of the solder is 32-37 μm.

[0014] Preferably, the liquidus temperature of the solder is 610-670°C.

[0015] A method for preparing the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder as described above comprises the following steps:

[0016] S1. Prepare Ag, Cu, Al, Sn, Y, and Sc according to the formula ratio;

[0017] S2. The raw materials prepared in step S1 are vacuum melted under stirring and repeatedly melted several times to obtain a master alloy ingot;

[0018] S3. The master alloy ingot is subjected to vacuum induction melting, and after the metal is completely melted, gas atomization is performed to pulverize the ingot to obtain the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder.

[0019] Preferably, the purity of each metal in the raw material is not less than 99.9 wt.%.

[0020] Preferably, in step S2, the stirring method adopts electromagnetic stirring, and the number of smelting is not less than 5 times.

[0021] Preferably, in step S3, the gas atomization powder making process uses inert gas as the atomization medium, and the pressure of the atomization gas is 3-5 MPa.

[0022] Application of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder described in any of the aforementioned embodiments or the solder prepared by the preparation method of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder described in any of the aforementioned embodiments in brazing of ceramics and titanium alloys.

[0023] A method for preparing a ceramic and titanium alloy welded joint comprises the following steps:

[0024] The Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic brazing material described in any one of the aforementioned embodiments is laid between a titanium alloy substrate and a ceramic substrate, a pressure head is assembled, vacuum brazing is performed, and cooling is performed after brazing is completed to obtain the welded joint.

[0025] Preferably, the titanium alloy substrate includes any one of a TC4 substrate, a pure titanium substrate, and a TC1 substrate.

[0026] Preferably, the ceramic substrate includes any one of a SiO2 ceramic substrate, a ZrO2 ceramic substrate, and a Si3N4 ceramic substrate.

[0027] Preferably, the vacuum brazing temperature is 660-720° C., and the holding time is 8-15 minutes.

[0028] Preferably, the shear strength of the welding area of ​​the welding joint is not less than 240 MPa.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic solder provided by the present invention has a thermal expansion coefficient that is more closely matched to titanium alloys and ceramics, and can reduce residual stress caused by thermal mismatch; the solder also has good wettability to titanium alloys and ceramics, which facilitates the spreading and bonding of the solder on the surfaces of titanium alloys and ceramics; the addition of Y and Sc helps to inhibit the formation of a brittle reaction layer, improves the bonding quality of the joint, and also has the effect of purifying grain boundaries and improving alloy properties; when the Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic solder provided by the present invention is used for brazing titanium alloys and ceramics, the joint strength is high, and the shear strength of the welding area can reach 289 MPa, thereby solving the technical problem of difficult welding of titanium alloys and ceramics or low joint strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a scanning electron microscope photograph of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0034] The first aspect of the present invention provides an Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder, which comprises the following components in atomic percentage: Ag 54% to 63%, Cu 16.5% to 19.5%, Al 5.5% to 12.5%, Sn 7.5% to 14.5%, Y 1.0% to 2.5%, and Sc 1.0% to 1.7%.

[0035] There are large differences in the elastic modulus and thermal expansion coefficient between ceramics and titanium alloys. The thermal mismatch during the cooling process leads to large residual stress in the joint, which seriously affects the quality of the joint. In addition, the chemical properties of titanium alloys and ceramics are quite different. Conventional metal brazing filler metals cannot form a good metallurgical bond with both ceramics and titanium alloys at the same time. Although the addition of active elements can promote the wetting of the brazing filler metal on the ceramic surface, the addition of active elements will lead to the formation of a brittle reaction layer, affecting the bonding quality of the joint. Multi-principal-element eutectic Ag-based solders can achieve higher performance improvements and a wider range of applications by introducing more diverse compositions and more complex structures. The atomic diffusion rate of multi-principal-element solders is controlled by their unique delayed diffusion effect and high-entropy effect, which can effectively inhibit atomic diffusion between the solder and the high-temperature alloy during the brazing process, reduce brittle intermetallic compounds in the joint, and improve the microstructure and mechanical properties of the joint. They also generally have excellent mechanical properties, including high strength and hardness, which gives joints using high-entropy solders higher shear strength and fracture strength. The design of multi-principal-element alloy compositions provides a wide range of composition regulation, allowing the thermal expansion coefficient of the solder to be adjusted over a wide range to better match titanium alloys and ceramics, thereby reducing residual stress caused by thermal mismatch. In addition, combined with the eutectic composition design, the solder forms a relatively fine and uniform microstructure during cooling, reducing dendrite segregation and the formation of shrinkage cavities, thereby improving the quality of the welded joint.

[0036] The present invention is based on the design concept of multiple principal elements and eutectic composition. Al, Cu, Sn, Y, and Sc elements are added to the Ag-based solder to form an Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder, which reduces the brazing temperature, has good diffusion ability, avoids the generation of brittle compound phases, and significantly improves the joint quality and mechanical properties. Among them, the addition of Al helps to adjust the thermal expansion coefficient of the solder to make it more compatible with titanium alloys and ceramics, thereby reducing the residual stress caused by thermal mismatch, and the appropriate addition of Al can improve the wettability of the solder to the surface of titanium alloys and ceramics, which helps to form a good metallurgical bond; Cu can react with the elements in the titanium alloy to form a strong metallurgical bond, and the price of Cu is relatively low, so the appropriate addition can reduce the cost of the solder; the addition of Sn can reduce the melting temperature of the solder, which helps to achieve a good metallurgical bond at a lower welding temperature, and the addition of Sn can also improve the flow of the solder. Mobility, making it easier to fill the gap between titanium alloy and ceramic; Y has the function of purifying grain boundaries, which can reduce impurities and defects in the brazing filler metal. The addition of Y helps to improve the strength and toughness of the joint and enhance the fatigue resistance of the joint; Y also helps to inhibit the formation of brittle reaction layer between titanium alloy and ceramic and improve the bonding quality of the joint; Sc has the function of refining grains, which can improve the microstructure of the brazing filler metal and improve the mechanical properties of the joint. The addition of Sc also helps to improve the oxidation resistance of the brazing filler metal and extend the service life of the joint; the synergistic effect of Y and Sc can significantly improve the welding quality of ceramic and titanium alloy.

[0037] The Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic solder provided by the present invention matches the thermal expansion coefficient of titanium alloys and ceramics, and can reduce residual stress caused by thermal mismatch; the solder also has good wettability to titanium alloys and ceramics, can reduce the tension between the liquid solder and the surfaces of the titanium alloys and ceramics, make the solder easier to spread on the welding interface, and facilitate the spreading and bonding of the solder on the surfaces of the titanium alloys and ceramics; the addition of Y and Sc helps to inhibit the formation of a brittle reaction layer, and Y and Sc also have excellent corrosion resistance. Their addition can improve the bonding quality of the joint, form a strong metallurgical bond, and thus increase the strength of the joint; when the Ag-Cu-Al-Sn-Y-Sc multi-principal-element eutectic solder provided by the present invention is used for brazing titanium alloys and ceramics, the shear strength of the welding area can reach 289 MPa, and is suitable for connecting titanium alloys with difficult-to-weld materials such as ceramics, thereby solving the technical problem of difficult welding of titanium alloys and ceramics.

[0038] In some embodiments, typically but not limiting, for example, the atomic percentage of Ag can be any value among 54%, 56%, 58%, 60%, 62%, 62.4%, and 63%, or a range consisting of any two values; the atomic percentage of Cu can be any value among 16.5%, 17.1%, 17.6%, 18%, 18.5%, and 19.5%, or a range consisting of any two values; the atomic percentage of Al can be any value among 5.5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, and 12.5%, or a range consisting of any two values; The atomic percentage of Sn can be any point value among 7.7%, 8%, 8.5%, 9%, 9.6%, 10%, 11%, 12%, 13%, 14%, 14.4%, or a range value consisting of any two point values; the atomic percentage of Y can be any point value among 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.3%, 2.5%, or a range value consisting of any two point values; the atomic percentage of Sc can be any point value among 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, or a range value consisting of any two point values.

[0039] In some specific embodiments of the present invention, in the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder, the atomic content ratio of Y and Sc is 1-2.5:1. For example, it can be any point value among 1:1, 1.5:1, 2:1, 2.5:1, or a range value consisting of any two point values. Reasonable control of the ratio between the two can better inhibit the formation of a brittle reaction layer, purify the grain boundaries, improve the microstructure, and improve the mechanical properties of the joint.

[0040] In some specific embodiments of the present invention, the liquidus temperature of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder is 610-670°C, for example, it can be any point value among 610°C, 615°C, 620°C, 630°C, 640°C, 650°C, 660°C, and 670°C, or a range value consisting of any two point values; the solder has a low melting temperature, which can reduce the welding temperature of titanium alloy and ceramic, and is beneficial to improving the joint strength.

[0041] In some specific embodiments of the present invention, the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder is in powder form, and the average particle size of the solder is 32-37 μm. For example, it can be any point value among 32 μm, 32.7 μm, 34 μm, 35 μm, 36.2 μm, 37 μm, or a range value consisting of any two point values.

[0042] A second aspect of the present invention provides a method for preparing the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to any one of the aforementioned embodiments, comprising the following steps:

[0043] S1. Prepare Ag, Cu, Al, Sn, Y, and Sc according to the formula ratio;

[0044] S2. The raw materials prepared in step S1 are vacuum melted under stirring and repeatedly melted several times to obtain a master alloy ingot;

[0045] S3. The master alloy ingot is subjected to vacuum induction melting. After the metal is completely melted, gas atomization is performed to pulverize the ingot to obtain Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder.

[0046] The present invention can obtain a powder solder with an average particle size of 32μm-37μm under the gas atomization powder making technology. The prepared solder powder has a uniform and concentrated particle size distribution and can be used for brazing composite components of titanium alloys and ceramics. The preparation process is simple, which is convenient for mass production and has broad application prospects and economic benefits.

[0047] In some specific embodiments of the present invention, the purity of each metal in the raw materials used is not less than 99.9 wt.%. The use of high-purity solder can reduce impurities in the solder and improve the cleanliness of the solder.

[0048] In some specific embodiments of the present invention, in step S2, electromagnetic stirring is used as the stirring method, and the number of melting times is not less than 5 times, in order to improve the uniformity of the components in the solder alloy.

[0049] In some specific embodiments of the present invention, in step S3, the gas atomization powder making process uses an inert gas as the atomizing medium. For example, high-purity argon can be used as the atomizing medium. The pressure of the atomizing gas is 3-5 MPa. For example, it can be any point value among 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, or a range value consisting of any two point values.

[0050] The third aspect of the present invention provides an application of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder described in any one of the aforementioned embodiments, or the solder prepared by the preparation method of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder described in any one of the aforementioned embodiments, in brazing of ceramics and titanium alloys.

[0051] A fourth aspect of the present invention provides a method for preparing a ceramic and titanium alloy welded joint, comprising the following steps:

[0052] The Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic brazing material described in any one of the aforementioned embodiments is laid between a titanium alloy substrate and a ceramic substrate, a pressure head is assembled, vacuum brazing is performed, and cooling is performed after brazing is completed to obtain the welded joint.

[0053] The method of the present invention adopts Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder to weld ceramics and titanium alloys, which can reduce residual stress caused by thermal mismatch generated by differences in thermal expansion coefficients, improve the wettability of the solder on the surfaces of ceramics and titanium alloys, and inhibit the generation of a brittle reaction layer, thereby improving the welding quality of ceramics and titanium alloys.

[0054] In some specific embodiments of the present invention, the titanium alloy substrate used includes any one of a TC4 substrate, a pure titanium substrate, and a TC1 substrate.

[0055] In some specific embodiments of the present invention, the ceramic substrate used includes any one of a SiO2 ceramic substrate, a ZrO2 ceramic substrate, and a Si3N4 ceramic substrate.

[0056] In some specific embodiments of the present invention, the vacuum brazing temperature is 660-720°C, and the holding time is 8-15 minutes; typically but not limitatively, for example, it can be any point value among 665°C, 670°C, 680°C, 690°C, 700°C, 710°C, 719°C or a range value consisting of any two point values, and the holding time can be any point value among 8 minutes, 10 minutes, 12 minutes, 14 minutes, 15 minutes or a range value consisting of any two point values. The welding temperature of the method of the present invention is low, which is conducive to improving the strength of the joint.

[0057] In some specific embodiments of the present invention, the shear strength of the welding area of ​​the obtained weld joint is not less than 240 MPa. For example, it can be any point value among 247 MPa, 260 MPa, 271 MPa, 289 MPa, 300 MPa or a range value consisting of any two point values.

[0058] The following describes some embodiments of the present invention in detail with reference to specific application examples. Unless otherwise specified, the raw materials used in the examples can be purchased from the market.

[0059] Example 1

[0060] A Ag-based multi-principal element eutectic solder 54.1 Cu 17.1 Al 12 Sn 14.4 Y 1.2 Sc 1.2 (at.%), and its preparation method comprises the following steps:

[0061] S1. Ingredients: Ag (99.9 wt.%), Cu (99.95 wt.%), Al (99.999 wt.%), Sn (99.9 wt.%), Y (99.9 wt.%), and Sc (99.9 wt.%) were accurately mixed according to the above element ratios.

[0062] S2. Melting of master alloy: Place the precisely proportioned raw materials in a water-cooled copper crucible in an arc melting furnace, and use a mechanical pump and a molecular pump to evacuate the furnace to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere. In order to ensure the uniformity of the composition of the solder block, electromagnetic stirring technology was used and the melting was repeated 5 times. After the melting was completed, a master alloy ingot with uniform composition was obtained;

[0063] S3. Powder preparation: The smelted master alloy is placed in a quartz tube with a 0.4 mm bottom opening in a gas atomization powder making furnace and fixed in an induction coil. The furnace is then pumped to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere, and the alloy was melted by high-frequency induction heating. At the same time, high-purity argon was used as the atomizing gas. The atomizing gas pressure was set to 4 MPa and the temperature was 715 ° C. After the atomization was completed, argon was blown into the atomizing chamber until the atmospheric pressure was restored. Then, the Ag-based multi-principal element eutectic solder powder prepared by the gas atomization method was collected.

[0064] The solder powder prepared by the above preparation method has uniform and concentrated particle size distribution, with an average particle size of about 35.8μm. The scanning electron microscope photo shows Figure 1 ; Its liquidus temperature is about 615℃.

[0065] Example 2

[0066] A Ag-based multi-principal element eutectic solder 61.9 Cu 19 Al6Sn 9.6 Y 2.3 Sc 1.2 (at.%), and its preparation method comprises the following steps:

[0067] S1. Ingredients: Ag (99.9 wt.%), Cu (99.95 wt.%), Al (99.999 wt.%), Sn (99.9 wt.%), Y (99.9 wt.%), and Sc (99.9 wt.%) were accurately mixed according to the above element ratios.

[0068] S2. Melting of master alloy: Place the precisely proportioned raw materials in a water-cooled copper crucible in an arc melting furnace, and use a mechanical pump and a molecular pump to evacuate the furnace to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere. In order to ensure the uniformity of the composition of the solder block, electromagnetic stirring technology was used and the melting was repeated 5 times. After the melting was completed, a master alloy ingot with uniform composition was obtained;

[0069] S3. Powder preparation: The smelted master alloy is placed in a quartz tube with a 0.4 mm bottom opening in a gas atomization powder making furnace and fixed in an induction coil. The furnace is then pumped to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere, and the alloy was melted by high-frequency induction heating. At the same time, high-purity argon was used as the atomizing gas. The atomizing gas pressure was set to 4 MPa and the temperature was 770 ° C. After the atomization was completed, argon was blown into the atomizing chamber until the atmospheric pressure was restored. Then, the Ag-based multi-principal element eutectic solder powder prepared by the gas atomization method was collected.

[0070] The solder powder prepared by the above preparation method has a uniform and concentrated particle size distribution, an average particle size of about 36.2 μm, and a liquidus temperature of about 669°C.

[0071] Example 3

[0072] A Ag-based multi-principal element eutectic solder 62.4 Cu 17.1 Al9Sn 7.7 Y 2.3 Sc 1.5 (at.%), and its preparation method comprises the following steps:

[0073] S1. Ingredients: Ag (99.9 wt.%), Cu (99.95 wt.%), Al (99.999 wt.%), Sn (99.9 wt.%), Y (99.9 wt.%), and Sc (99.9 wt.%) were accurately mixed according to the above element ratios.

[0074] S2. Melting of master alloy: Place the precisely proportioned raw materials in a water-cooled copper crucible in an arc melting furnace, and use a mechanical pump and a molecular pump to evacuate the furnace to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere. In order to ensure the uniformity of the composition of the solder block, electromagnetic stirring technology was used and the melting was repeated 5 times. After the melting was completed, a master alloy ingot with uniform composition was obtained;

[0075] S3. Powder preparation: The smelted master alloy is placed in a quartz tube with a 0.4 mm bottom opening in a gas atomization powder making furnace and fixed in an induction coil. The furnace is then pumped to a high vacuum state (vacuum degree not less than 6.0×10 -3 Pa), and then filled with high-purity argon as a protective atmosphere, and the alloy was melted by high-frequency induction heating. At the same time, high-purity argon was used as the atomizing gas. The atomizing gas pressure was set to 4 MPa and the temperature was 770 ° C. After the atomization was completed, argon was blown into the atomizing chamber until the atmospheric pressure was restored. Then, the Ag-based multi-principal element eutectic solder powder prepared by the gas atomization method was collected.

[0076] The solder powder prepared by the above preparation method has a uniform and concentrated particle size distribution, an average particle size of about 32.7 μm, and a liquidus temperature of about 666°C.

[0077] Comparative Example 1

[0078] Comparative Example 1 is similar to Example 1, except that no Al is added to the ingredients and the solder composition is Ag. 66.1 Cu 17.1 Sn 14.4 Y 1.2 Sc 1.2 (at.%), and the rest of the preparation process is the same as that in Example 1.

[0079] The average particle size of the prepared solder powder is about 37.5 μm, and the liquidus temperature is about 672°C.

[0080] Comparative Example 2

[0081] Comparative Example 2 is similar to Example 1, except that no Sn is added to the ingredients and the solder composition is Ag. 68.5 Cu 17.1 Al 12 Y 1.2 Sc 1.2 (at.%), and the rest of the preparation process is the same as that in Example 1.

[0082] The average particle size of the prepared solder powder is about 36.1 μm, and the liquidus temperature is about 690°C.

[0083] Comparative Example 3

[0084] Comparative Example 3 is similar to Example 1, except that no Y and Sc are added to the ingredients, and the solder composition is Ag. 56.5 Cu 17.1 Al 12 Sn 14.4 (at.%), and the rest of the preparation process is the same as that in Example 1.

[0085] The average particle size of the prepared solder powder is about 34.6 μm, and the liquidus temperature is about 591°C.

[0086] Comparative Example 4

[0087] Comparative Example 4 is similar to Example 1, except that Y is replaced by an equal amount of Sc in the ingredients and the solder composition is Ag. 54.1 Cu 17.1 Al 12 Sn 14.4 Sc 2.4 (at.%), and the rest of the preparation process is the same as that in Example 1.

[0088] The average particle size of the prepared solder powder is about 37.9 μm, and the liquidus temperature is about 626°C.

[0089] Comparative Example 5

[0090] Comparative Example 5 is similar to Example 1, except that Sc is replaced by an equal amount of Y in the ingredients, and the solder composition is Ag. 54.1 Cu 17.1 Al 12 Sn 14.4 Y 2.4 (at.%), and the rest of the preparation process is the same as that in Example 1.

[0091] The average particle size of the prepared solder powder is about 38.2 μm, and the liquidus temperature is about 598°C.

[0092] Test example

[0093] The Ag-based multi-principal element eutectic solders in the embodiments and comparative examples were used to weld ceramics and titanium alloys to prepare welded joints, and the shear strength of the joints was tested according to GB / T 11363-2008 Test Method for Strength of Brazed Joints.

[0094] The welding process is as follows: Ag-based multi-principal eutectic solder powder is evenly spread between the Ti-6Al-4V (TC4) substrate and the SiO2 ceramic; after assembling the indenter, the whole is placed in a vacuum brazing furnace; the brazing process parameters are set to hold the brazing temperature for 10 minutes, and the vacuum degree is 1.0×10 -2 Pa; After brazing is completed, cool to room temperature with the furnace to obtain a welded joint.

[0095] The brazing temperature and shear strength test results of the joints are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] Although the present invention has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are merely intended to illustrate the technical solutions of the present invention rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and scope of the present invention. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. An Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder, characterized in that: Calculated by atomic percentage, it includes the following components: Ag 54% to 63%, Cu 16.5% to 19.5%, Al 5.5% to 12.5%, Sn 7.5% to 14.5%, Y 1.0% to 2.5%, and Sc 1.0% to 1.7%.

2. The Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to claim 1, characterized in that: The atomic content ratio of the Y and the Sc is 1-2.5:

1.

3. The Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to claim 1, characterized in that: The solder is in powder form, and the average particle size of the solder is 32-37 μm; And / or, the liquidus temperature of the solder is 610-670°C.

4. The method for preparing the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to any one of claims 1 to 3, characterized in that: The steps include: S1. Prepare Ag, Cu, Al, Sn, Y, and Sc according to the formula ratio; S2. The raw materials prepared in step S1 are vacuum melted under stirring and repeatedly melted several times to obtain a master alloy ingot; S3. The master alloy ingot is subjected to vacuum induction melting, and after the metal is completely melted, gas atomization is performed to pulverize the ingot to obtain the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder.

5. The method for preparing the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to claim 4, characterized in that: Contains at least one of the following characteristics: (1) The purity of each metal in the raw materials is not less than 99.9 wt.%; (2) In step S2, the stirring method adopts electromagnetic stirring, and the number of smelting is not less than 5 times; (3) In step S3, the gas atomization powder making process uses inert gas as the atomization medium, and the pressure of the atomization gas is 3-5 MPa.

6. Use of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to any one of claims 1 to 3 or the solder prepared by the preparation method of the Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic solder according to claim 4 or 5 in brazing ceramics and titanium alloys.

7. A method for preparing a ceramic and titanium alloy welded joint, characterized in that: The following steps are involved: The Ag-Cu-Al-Sn-Y-Sc multi-principal element eutectic brazing material according to any one of claims 1 to 3 is laid between a titanium alloy substrate and a ceramic substrate, a pressure head is assembled, vacuum brazing is performed, and cooling is performed after the brazing is completed to obtain the welded joint.

8. The method for preparing a ceramic and titanium alloy welded joint according to claim 7, characterized in that: The titanium alloy substrate includes any one of a TC4 substrate, a pure titanium substrate, and a TC1 substrate; And / or, the ceramic substrate includes any one of a SiO2 ceramic substrate, a ZrO2 ceramic substrate, and a Si3N4 ceramic substrate.

9. The method for preparing a ceramic and titanium alloy welded joint according to claim 7, characterized in that: The vacuum brazing temperature is 660-720° C., and the holding time is 8-15 minutes.

10. The method for preparing a ceramic and titanium alloy welded joint according to any one of claims 7 to 9, characterized in that: The shear strength of the welding area of ​​the welding joint is not less than 240 MPa.

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