Medium-entropy alloy brazing filler metal and preparation method and brazing method thereof

Abstract

The invention relates to the technical field of brazing, and provides Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal used for pure titanium and titanium alloy brazing and a using method of the Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal. The invention provides Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal. The brazing filler metal comprises the following components in percentage by weight: 9.5-13.9% of Ti, 0.5-1.5% of Hf, 0.5-1.5% of Ni, 0.5-1.5% of Cu and the balance of Zr. Ni: 5.5 to 9.5%; 5.0 to 9.5 percent of Cu; 2.0 to 8.5 parts of Co; 0 to 0.6% of Hf; zr: the balance. The brazing filler metal has the following technical effects that the liquidus temperature of the brazing filler metal ranges from 769 DEG C to 782 DEG C, the brazing filler metal is easily formed into amorphous brazing filler metal alloy, and the shear strength of a pure titanium-titanium alloy connector obtained after heat preservation is conducted for 10 minutes at the brazing temperature of 810 DEG C to 828 DEG C reaches 243 MPa to 280 MPa.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202311825744.2, filed with the Chinese Patent Office on December 27, 2023, entitled "A Hexa-Element Medium-Entropy Alloy Brazing Filler and Its Preparation Method and Brazing Method". Technical Field

[0002] This invention belongs to the field of brazing technology, and particularly relates to a medium-entropy alloy brazing filler metal, its preparation method, and brazing method. Background Technology

[0003] Titanium and its alloys have high specific strength and good corrosion resistance, making them one of the main structural materials for modern aircraft and engines. They can reduce the weight of aircraft or engines and improve structural efficiency. For brazing of titanium alloys, Ti-based (Ti content greater than 40% by weight) or TiZr-based (Ti content greater than 35% by weight and Zr content greater than 20% by weight) brazing filler metals are usually selected as brazing materials to obtain better joint microstructure and corresponding higher joint strength and better corrosion resistance.

[0004] However, the phase transition temperature T of pure titanium β The required brazing temperature is 882℃, meaning brazing connections must be performed at temperatures below 882℃. This applies to TC16 (Ti-3Al-5Mo-4.5V, weight percentage) and TC18.

[0005] (Ti-5Al-5Mo-5V-1Cr-1Fe, weight percentage) titanium alloys have phase transformation temperatures as low as 840℃~880℃, meaning the brazing temperature for brazing connections must be below 840℃. Furthermore, to ensure the base titanium alloy does not undergo a phase transformation during brazing, a safe brazing temperature should not exceed 830℃. Considering that brazing is generally performed at a temperature 30℃-50℃ higher than the melting temperature of the brazing filler metal, the ideal brazing filler metal for pure titanium materials and titanium alloys such as TC6 and TC18 should ideally have a liquidus temperature below 790℃. Moreover, and very importantly, for brazing connections of pure titanium and titanium alloys, whether in aircraft ductwork or thin-walled complex structures for aerospace and marine heat exchangers, brazed joints must possess both high strength and good ductility to ensure the safety and service life of the welded structure.

[0006] However, currently, Ti-based or TiZr-based solders have high liquidus temperatures. For example, the typical Ti-15Cu-15Ni alloy (by weight) has a high liquidus temperature and is only suitable for brazing the β-phase transformation temperature T. βTitanium alloys with a liquidus temperature above 960℃, such as the Ti-13Zr-21Cu-9Ni alloy (by weight), still have relatively high liquidus temperatures, limiting brazing connections to 920℃-940℃. While some brazing fillers can achieve brazing connections of pure titanium and titanium alloys at around 880℃, the joint strength rarely exceeds 500MPa, and the joints remain noticeably brittle. Generally, after addressing the basic weldability of a base material, further reducing the melting temperature of the filler metal to lower the required brazing temperature, while simultaneously increasing joint strength and reducing brittleness, presents a significant technical challenge. Currently, there is a lack of filler metal materials capable of brazing pure titanium or pure titanium to titanium alloys at temperatures below 872℃, while also providing brazed joints with both high strength and ductility. Another point is that, while meeting the mechanical properties of the brazed joint, minimizing the brazing temperature to save energy has always been a goal pursued in the field of pure titanium and titanium alloy brazing. However, there is currently a lack of brazing materials that can braze pure titanium and titanium alloys at temperatures below 830℃ and also give the brazed joint high strength. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal. The brazing filler metal provided by the present invention has a liquidus temperature between 769°C and 782°C, and can be used for brazing pure titanium or pure titanium and titanium alloy at a temperature of 815°C to 828°C, and the obtained brazed joint has high strength.

[0008] This invention provides a Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy solder, wherein the weight percentage of the solder components is as follows:

[0009] Ti: 9.5~13.9; Ni: 5.5~9.5; Cu: 5.0~9.5; Co: 2.0~8.5; Hf: 0.0~0.6; Zr: balance.

[0010] Preferably, the weight percentage of the solder components is:

[0011] Ti: 9.5~13.0; Ni: 5.5~9.0; Cu: 5.0~9.5; Co: 3.0~8.0; Hf: 0.0~0.6; Zr: balance.

[0012] Preferably, the liquidus temperature of the brazing filler metal is 769°C to 782°C;

[0013] The brazing filler metal is one or more of the following medium-entropy alloy brazing filler metals in the form of: amorphous foil strip, powder, alloy block, or powder sintered body.

[0014] This invention provides a method for preparing Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy solder, comprising:

[0015] A) Prepare alloy ingots by smelting metal raw materials;

[0016] B) Prepare medium-entropy alloy brazing filler metal from alloy ingots; the shape of the medium-entropy alloy brazing filler metal includes one of the following: amorphous foil strip, powder, alloy block, and powder sintered body.

[0017] Preferably, step B) specifically includes one or more of the following steps:

[0018] i) The alloy ingot is prepared into alloy powder brazing filler metal by argon atomization powder preparation method or plasma rotating electrode atomization method;

[0019] ii) The alloy ingot is processed into amorphous alloy foil brazing filler metal using a single-roll rapid quenching method;

[0020] iii) Mechanically crush the alloy ingot to obtain a brazing alloy block;

[0021] iv) First, prepare powdered brazing filler metal according to the above method, and then press and sinter it to obtain a sintered brazing filler metal body.

[0022] This invention provides the application of the Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal described in any one of the above-mentioned claims in the brazing of pure titanium and / or titanium alloys.

[0023] This invention provides a brazing method for pure titanium / or titanium alloys, comprising the following steps:

[0024] a) Material preparation: Prepare the base material of pure titanium and / or titanium alloy to be welded. After pretreatment such as test piece processing and surface cleaning, the pretreated base material is obtained.

[0025] b) Add solder to the surface of the pretreated base material to be welded to obtain the assembled component; the solder is the solder described in the above technical solution or the solder prepared by the preparation method described in the above technical solution;

[0026] c) Brazing the assembled components yields the final product.

[0027] Preferred,

[0028] The pretreatment step a) specifically involves removing oxides, oils, or surface contaminants from the surface of the base material;

[0029] Step b) further includes controlling the brazing gap between the substrates to be brazed to be 0.01 to 0.08 mm using tooling fixtures.

[0030] Preferably, the brazing temperature in step c) is specifically:

[0031] When the substrate contains pure titanium, the brazing temperature T b The temperature range is 810℃~860℃.

[0032] When the substrate being welded is TC16 or TC18 titanium alloy, the brazing temperature T b The temperature range is 810℃~828℃;

[0033] When the substrate is a titanium alloy with a phase transformation temperature higher than 840℃, the brazing temperature T b The temperature can be 810℃~828℃, or it can be 10℃ lower than the phase transformation temperature of the titanium alloy base material being welded.

[0034] Preferably, the brazing method in step c) is vacuum brazing or induction heating brazing;

[0035] The specific vacuum brazing parameters are: the vacuum level inside the furnace is not less than 1×10⁻⁶. -3 Pa, heating at a rate of 20–40 °C / min to 500 °C; then continuing to heat at a rate of 15–25 °C / min to T b Hold the temperature for 10 to 25 minutes; then cool down at a rate of 15 to 25°C / min until the furnace reaches room temperature.

[0036] The specific parameters for induction heating brazing are: vacuum degree below 2×10⁻⁶. -1 Inert gas is introduced to a pressure of 70–100 kPa, and then heated to T at a heating rate of 50–100 °C / min under inert gas conditions. b Keep warm for 1 to 10 minutes, then stop induction heating and allow to cool naturally to room temperature.

[0037] Compared with existing technologies, this invention provides a Zr-Ti-Hf-Ni-Cu-Co hexavalent medium-entropy alloy brazing filler metal, wherein the weight percentage of the filler metal composition is: Ti: 9.5-13.9; Ni: 5.5-9.5; Cu: 5.0-9.5; Co: 2.0-8.5; Hf: 0.0-0.6; Zr: balance. This invention has the following technical advantages: the liquidus temperature of the filler metal is between 769℃ and 782℃, the filler metal is easily formed into an amorphous alloy, and the shear strength of the pure titanium-titanium alloy joint obtained by holding at a brazing temperature of 810℃ to 828℃ for 10 minutes reaches 243-280 MPa.

[0038] The advantages and beneficial effects of the brazing filler metal of this invention are as follows:

[0039] (1) Characteristics and advantages of the elemental composition of the solder alloy: Utilizing the principle of diversified alloy design, this invention patent design incorporates a total of 6 constituent elements. Among them, Zr, Ti, and Hf are three elements that are infinitely miscible with each other, and there is no tendency for them to form brittle intermetallic compounds. Simultaneously, Ni, Cu, and Co are added to the solder alloy as melting point reducing elements. Through the principles of ternary low-melting-point eutectics such as Cu-Ni-Zr, Cu-Ni-Ti, and Cu-Ti-Zr, as well as binary low-melting-point eutectics such as Co-Ti and Co-Zr, they collectively achieve the effect of lowering the melting point of the solder alloy. (See Appendix) Figures 1-5 Furthermore, thermodynamic calculations show that the mixing entropy ΔS of the hexa-element solder alloy of this invention is... mix (J.K.) -1 mol -1 The value is between 9.72 and 11.32, satisfying the thermodynamic condition ΔS for high-entropy alloys. mix The value falls within the range of 1.0R-1.5R, indicating that it belongs to the medium-entropy alloy brazing filler metal. Therefore, it can play a good role in strengthening and toughening in brazed joints of pure titanium and pure titanium combined with titanium alloy.

[0040] (2) The melting temperature of the brazing alloy is effectively reduced, meeting the ideal requirement that the brazing temperature does not exceed 830℃. In the applied Zr-Ti-Hf-Ni-Cu-Co hexa-element brazing alloy, Ni, Cu, and Co are used in combination to reduce melting point. The melting point reduction effect is much better than that of Cu, Ni, and Co alone, or any two of them combined. The actual liquidus temperature of the brazing alloy is between 769℃ and 782℃. (See Appendix) Figure 6 Therefore, brazing can be performed within a temperature range of 810-828℃, which avoids damage to the properties of the base material caused by excessively high brazing temperatures and also helps save energy during the brazing process. This is particularly true for large gap joints (e.g., 0.3mm to 3mm), where brazing requires a long diffusion sintering process (e.g., more than 1 hour) to densify the brazed joint by simultaneously adding titanium alloy powder and brazing filler alloy powder. In these cases, the energy-saving effect of this lower brazing temperature is even more pronounced.

[0041] (3) Since the liquidus temperature of the brazing filler metal of the present invention is below 782°C, it is particularly suitable for brazing TC16 and TC18 titanium alloys with a phase transformation temperature of 840°C to 880°C. In addition, it is also suitable for brazing pure titanium-titanium alloy composite joints, and can be used for brazing conventional titanium alloys such as TC4. It is applicable to a wide range of titanium alloy base materials, and the brazing temperature can be selected in a wide range. For example, for TA2 pure titanium, the brazing temperature can be in the range of 810°C to 870°C, and for TC4 titanium alloy (whose phase transformation temperature is about 970°C), the brazing temperature can be in the range of 830°C to 910°C.

[0042] (4) The brazing alloy of this invention is designed with full consideration of the requirement for good amorphous foil forming capability. Especially for brazing connections of heat exchangers with complex multi-layered thin-walled structures composed of pure titanium fins and titanium alloy partitions, the use of complete and continuous amorphous alloy foil for pre-welding filling and assembly between layers ensures convenient and efficient assembly, as well as stable and controllable brazing quality. Of the six constituent elements of the brazing alloy of this invention, one category consists of Zr, Ti, and Hf, and the other consists of Ni, Cu, and Co. Each category contains similar elements, but the elements within each category are dissimilar (see Appendix). Figure 7 By combining appropriate amounts of each component to achieve a combined melting point reduction, this design approach fully utilizes the design principles of amorphous alloys, such as the "eutectic point criterion, atomic size differences, and coexistence of similar and dissimilar elements." Therefore, under the premise of ensuring a sufficiently low melting temperature, the solder of this invention exhibits significantly better amorphous foil formation capability than the Zr-Ti-Ni system and ZrTiNiNb(Hf) solder. Using a single-roll rapid quenching method, amorphous solder foil with a width of 25-50 mm and a thickness of 25-60 μm can be stably obtained. Solder foils obtained from different batches all exhibit amorphous characteristics. (See attached figure.) Figure 8 Meanwhile, because the solder of this invention has a strong ability to form amorphous foil strips, the yield of solder foil strips is increased to more than 1.5 times that of Zr-Ti-Ni system solders and Zr-Ti-Ni-Nb(Hf) solders.

[0043] (5) Using the brazing filler metal of the present invention, the microstructure of pure titanium-titanium alloy composite joints, for example, pure titanium-pure titanium and pure titanium-titanium alloy brazed joints under brazing conditions of 825℃-10min, is shown in the attached figure. Figure 9 As shown, the joint center area is approximately 30 μm wide, and a diffusion reaction zone of approximately 25-40 μm wide exists between the joint center area and the pure titanium-titanium alloy base material being welded. However, the entire brazed joint does not exhibit obvious bright white Cu-Ti, Cu-Zr, Ni-Ti, Ni-Zr, Co-Ti, or Co-Zr intermetallic compounds. The brazing filler metal of this invention employs a balanced melting point reduction method with Ni, Cu, and Co elements, effectively avoiding the tendency to form strong brittle intermetallic compounds in the brazed joint due to excessive addition of any single element when melting point reduction is relied upon. When brazing is held at a sufficient temperature, Ni, Cu, and Co elements exist in solid solution form within the (Zr, Ti, Hf) solid solution. They do not cause joint brittleness but rather play a crucial role in strengthening the brazed joint. Therefore, using the brazing filler metal of this invention, under suitable brazing process conditions, the brazed joint obtained exhibits both good strength and ductility.

[0044] (6) The brazing filler metal of this invention exhibits extremely strong wetting, spreading, and gap-filling capabilities on pure titanium and titanium alloy substrates during brazing. For example, under vacuum heating conditions of 825℃-10min, the brazing filler metal shows good wettability on pure titanium TA2, with a wetting angle of only 37°. (See Appendix) Figure 10 Under vacuum brazing conditions of 860℃ for 10 minutes, it achieves a filler length of 75-90 mm for TA18 titanium alloy (see attached image). Figure 11 .

[0045] (7) The brazing filler metal of this invention achieves a comprehensive effect of high strength and good plasticity for brazing pure titanium and pure titanium and titanium alloy combinations at a brazing temperature of 850-865℃ and a holding time of 18-25 minutes: the tensile strength of TA2-TC4 and TA2-TA18 brazed joints at room temperature is above 530MPa, and the elongation of the two joints reaches above 10% and 12% respectively, fundamentally eliminating the brittle characteristics of brazed joints corresponding to traditional brazing filler metals and achieving a strong-plasticity match of the joint. At the same time, the shear strength of TA2-TA18, TA2-TC16, and TA2-TC18 joints obtained by brazing at 810-828℃ reaches 243MPa-280MPa at room temperature.

[0046] (8) As previously mentioned, the brazing filler metal of this invention does not contain high-melting-point Nb, and explicitly requires that the Hf content be controlled to no more than 2.0% by weight. At the same time, the addition of the three melting-reducing elements Ni, Cu, and Co is relatively balanced. These factors are conducive to obtaining a uniformly composed ingot through smelting. Furthermore, with a uniformly composed ingot, a uniformly composed, segregated amorphous alloy foil brazing filler metal can be easily obtained through a single-roller rapid quenching method. On the other hand, the uniformly composed ingot has been verified by two methods: argon atomization powder preparation and plasma rotating electrode atomization. The powder preparation process is safe and stable, and can obtain a uniformly composed powdered brazing filler metal.

[0047] (9) The brazing alloy itself has the characteristics of high alloying. During the brazing process, Cu, Ni and Co elements diffuse into the pure titanium and titanium alloy matrix to be welded, and Ti elements diffuse into the brazing seam. Therefore, the brazed joint is a TiZr(Hf) based super solid solution. The content of Cu, Ni and Co elements is relatively low. Therefore, the brazed joint not only has good mechanical properties, but also the high alloying characteristics of the brazed joint ensure its good corrosion resistance. Attached Figure Description

[0048] Figure 1 Cu-Ni-Zr ternary phase diagram;

[0049] Figure 2 Cu-Ni-Ti ternary phase diagram;

[0050] Figure 3 Cu-Co-Zr ternary phase diagram;

[0051] Figure 4 Co-Ti binary phase diagram;

[0052] Figure 5 Co-Zr binary phase diagram;

[0053] Figure 6 Two typical solid-liquid phase temperature ranges for medium-entropy alloy brazing filler metals;

[0054] Figure 7 A schematic diagram showing the positions of the constituent elements of medium-entropy alloy brazing filler metal in the periodic table;

[0055] Figure 8 Typical XRD pattern of amorphous solder foil;

[0056] Figure 9 Microstructure of pure titanium TA2-titanium alloy TA18 brazed joint (brazing at 825℃ for 10 min);

[0057] Figure 10 Cross-section of brazing filler metal on pure titanium TA2 under vacuum heating conditions of 825℃-10min;

[0058] Figure 11 The filler length of medium-entropy alloy brazing filler metal for titanium alloy TA18 reaches 75-90mm; (wedge-shaped brazing filler, total length perpendicular to both plates 93mm, one end raised by 1mm, brazing at 860℃ for 10min). Detailed Implementation

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0061] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0062] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0063] This invention provides a Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy solder, wherein the weight percentage of the solder components is as follows:

[0064] Ti: 9.5~13.9; Ni: 5.5~9.5; Cu: 5.0~9.5; Co: 2.0~8.5; Hf: 0.0~2.0; Zr: balance.

[0065] In the entropy alloy brazing filler metal of this invention, the weight percentage of Hf can specifically be 0, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.3, 1.4, 1.5, 1.7, 1.9, or 2.0; or any value within the range of the above two, selected from: 0–0.6, 0–0.7, 0–0.8, 0–0.9, 0–1.0, 0–1.2, 0–1.3, 0–1.4, 0–1.5, 0–1.7, 0–1.9, 0–2.0, 0.6–0.7. 0.6~0.8, 0.6~0.9, 0.6~1.0, 0.6~1.2, 0.6~1.3, 0.6~1.4, 0.6~1.5, 0.6~1.7, 0.6~1.9, 0.6~2.0, 0.7~0.8, 0.7~0.9, 0.7~1.0, 0.7~1.2, 0.7~1.3, 0.7~1.4, 0.7~1.5, 0.7~1.7, 0.7~1.9, 0.7~2.0, 0.8~0.9, 0.8~1 0, 0.8~1.2, 0.8~1.3, 0.8~1.4, 0.8~1.5, 0.8~1.7, 0.8~1.9, 0.8~2.0, 0.9~1.0, 0.9~1.2, 0.9~1.3, 0.9~1.4, 0.9~1.5, 0.9~1.7, 0.9~1.9, 0.9~2.0, 1.0~1.2, 1.0~1.3, 1.0~1.4, 1.0~1.5, 1.0~1.7, 1.0~1.9, 1. 0~2.0, 1.2~1.3, 1.2~1.4, 1.2~1.5, 1.2~1.7, 1.2~1.9, 1.2~2.0, 1.3~1.4, 1.3~1.5, 1.3~1.7, 1.3~1.9, 1.3~2.0, 1.4~1.5, 1.4~1.7, 1.4~1.9, 1.4~2.0, 1.5~1.7, 1.5~1.9, 1.5~2.0, 1.7~1.9, 1.7~2.0, 1.9~2.0.

[0066] In the entropy alloy brazing filler metal of this invention, the weight percentage of Ti can specifically be 9.5, 10.0, 10.2, 10.5, 11.5, 12, 12.3, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.2, 13.3, 13.5, 13.7, 13.9, or any value within the range of any two of the above. It can be selected from: 9.5–10.0, 9.5–10.2, 9.5–10.5, 9.5–11.5, 9.5–12, 9.5–12.3, 9.5–12.5, 9.5–12.6, 9.5–12.7, 9.5–12.8, 9.5–12.9, 9.5–13.0, 9.5–13.2, 9.5–13. .3, 9.5~13.5, 9.5~13.7, 9.5~13.9, 10.0~10.2, 10.0~10.5, 10.0~11.5, 10.0~12, 10.0~12.3, 10.0~12.5, 10.0~12.6, 10.0~12.7, 10.0~12.8, 10.0~12 0.9, 10.0~13.0, 10.0~13.2, 10.0~13.3, 10.0~13.5, 10.0~13.7, 10.0~13.9, 10.2~10.5, 10.2~11.5, 10.2~12, 10.2~12.3, 10.2~12.5, 10.2~12.6, 10.2 ~12.7, 10.2~12.8, 10.2~12.9, 10.2~13.0, 10.2~13.2, 10.2~13.3, 10.2~13.5, 10.2~13.7, 10.2~13.9, 10.5~11.5, 10.5~12, 10.5~12.3, 10.5~12.5, 1 0.5~12.6, 10.5~12.7, 10.5~12.8, 10.5~12.9, 10.5~13.0, 10.5~13.2, 10.5~13.3, 10.5~13.5, 10.5~13.7, 10.5~13.9, 11.5~12, 11.5~12.3, 11.5~12. 5, 11.5~12.6, 11.5~12.7, 11.5~12.8, 11.5~12.9, 11.5~13.0, 11.5~13.2, 11.5~13.3, 11.5~13.5, 11.5~13.7, 11.5~13.9, 12~12.3, 12~12.5, 12~12.6 12~12.7, 12~12.8, 12~12.9, 12~13.0, 12~13.2, 12~13.3, 12~13.5, 12~13.7, 12~13.9, 12.3~12.5, 12.3~12.6, 12.3~12.7, 12.3~12.8, 12.3~12.9, 12.3～13.0、12.3～13.2、12.3～13.3、12.3～13.5、12.3～13.7、12.3～13.9、12.5～12.6、12.5～12.7、12.5～12.8、12.5～12.9、12.5～13.0、12.5～13.2、12.5～13.3、12.5～13.5、12.5～13.7、12.5～13.9、12.6～12.7、12.6～12.8、12.6～12.9、12.6～13.0、12.6～13.2、12.6～13.3、12.6～13.5、12.6～13.7、12.6～13.9、12.7～12.8、12.7～12.9、12.7～13.0、12.7～13.2、12.7～13.3、12.7～13.5、12.7～13.7、12.7～13.9、12.8～12.9、12.8～13.0、12.8～13.2、12.8～13.3、12.8～13.5、12.8～13.7、12.8～13.9、12.9～13.0、12.9～13.2、12.9～13.3、12.9～13.5、12.9～13.7、12.9～13.9、13.0～13.2、13.0～13.3、13.0～13.5、13.0～13.7、13.0～13.9、13.2～13.3、13.2～13.5、13.2～13.7、13.2～13.9、13.3～13.5、13.3～13.7、13.3～13.9、13.5～13.7、13.5～13.9、13.7～13.9。.

[0067] In the entropy alloy brazing filler metal of this invention, the weight percentage of Ni can specifically be 5.5, 5.8, 6.0, 6.5, 6.8, 7.0, 7.2, 7.3, 7.5, 7.7, 7.8, 7.9, 8.0, 8.2, 8.3, 8.5, 8.7, 9.0, 9.5, or any value within the range of two of the above. It can be selected from: 5.5–5.8, 5.5–6.0, 5.5–6.5, 5.5–6.8, 5.5–7.0, 5.5–7.2, 5.5–7.3, 5.5–7.5, 5.5–7.7, 5.5–7.8, 5.5–7.9, 5.5–8.0, 5.5–8.2, 5.5–8.3, 5.5–8.5, 5.5–8.7, 5.5– 9.0, 5.5~9.5, 5.8~6.0, 5.8~6.5, 5.8~6.8, 5.8~7.0, 5.8~7.2, 5.8~7.3, 5.8~7.5, 5.8~7.7, 5.8~7.8, 5.8~7.9, 5.8~8.0, 5.8~8.2, 5.8~8.3, 5.8~8.5, 5 .8~8.7, 5.8~9.0, 5.8~9.5, 6.0~6.5, 6.0~6.8, 6.0~7.0, 6.0~7.2, 6.0~7.3, 6.0~7.5, 6.0~7.7, 6.0~7.8, 6.0~7.9, 6.0~8.0, 6.0~8.2, 6.0~8.3, 6.0~8. 5, 6.0~8.7, 6.0~9.0, 6.0~9.5, 6.5~6.8, 6.5~7.0, 6.5~7.2, 6.5~7.3, 6.5~7.5, 6.5~7.7, 6.5~7.8, 6.5~7.9, 6.5~8.0, 6.5~8.2, 6.5~8.3, 6.5~8.5, 6.5 ~8.7, 6.5~9.0, 6.5~9.5, 6.8~7.0, 6.8~7.2, 6.8~7.3, 6.8~7.5, 6.8~7.7, 6.8~7.8, 6.8~7.9, 6.8~8.0, 6.8~8.2, 6.8~8.3, 6.8~8.5, 6.8~8.7, 6.8~9.0 6.8~9.5, 7.0~7.2, 7.0~7.3, 7.0~7.5, 7.0~7.7, 7.0~7.8, 7.0~7.9, 7.0~8.0, 7.0~8.2, 7.0~8.3, 7.0~8.5, 7.0~8.7, 7.0~9.0, 7.0~9.5, 7.2~7.3, 7.2~7 5, 7.2~7.7, 7.2~7.8, 7.2~7.9, 7.2~8.0, 7.2~8.2, 7.2~8.3, 7.2~8.5, 7.2~8.7, 7.2~9.0, 7.2~9.5, 7.3~7.5, 7.3~7.7, 7.3~7.8, 7.3~7.9, 7.3~8.0, 7.3～8.2、7.3～8.3、7.3～8.5、7.3～8.7、7.3～9.0、7.3～9.5、7.5～7.7、7.5～7.8、7.5～7.9、7.5～8.0、7.5～8.2、7.5～8.3、7.5～8.5、7.5～8.7、7.5～9.0、7.5～9.5、7.7～7.8、7.7～7.9、7.7～8.0、7.7～8.2、7.7～8.3、7.7～8.5、7.7～8.7、7.7～9.0、7.7～9.5、7.8～7.9、7.8～8.0、7.8～8.2、7.8～8.3、7.8～8.5、7.8～8.7、7.8～9.0、7.8～9.5、7.9～8.0、7.9～8.2、7.9～8.3、7.9～8.5、7.9～8.7、7.9～9.0、7.9～9.5、8.0～8.2、8.0～8.3、8.0～8.5、8.0～8.7、8.0～9.0、8.0～9.5、8.2～8.3、8.2～8.5、8.2～8.7、8.2～9.0、8.2～9.5、8.3～8.5、8.3～8.7、8.3～9.0、8.3～9.5、8.5～8.7、8.5～9.0、8.5～9.5、8.7～9.0、8.7～9.5、9.0～9.5。.

[0068] In the entropy alloy brazing filler metal of this invention, the weight percentage of Cu can specifically be 5.0, 5.5, 5.8, 6.0, 6.2, 6.5, 6.8, 7.0, 7.2, 7.3, 7.5, 7.6, 7.7, 8.0, 9.0, or 9.5; or any value within the range of the above two, selected from: 5.0–5.5, 5.0–5.8, 5.0–6.0, 5.0–6.2, 5.0–6.5, 5.0–6.8, 5.0–7.0, 5.0–7.2, 5.0–7.3, 5.0–7.5, 5.0–7.6, 5.0–7.7, 5.0–8.0, 5.0–9.0, 5.0–9.5, 5.5–5.8, 5.5–6.0, or 5.5–6.2. 5.5~6.5, 5.5~6.8, 5.5~7.0, 5.5~7.2, 5.5~7.3, 5.5~7.5, 5.5~7.6, 5.5~7.7, 5.5~8.0, 5.5~9.0, 5.5~9.5, 5.8~6.0, 5.8~6.2, 5.8~6.5, 5.8~6.8, 5.8~ 7.0, 5.8~7.2, 5.8~7.3, 5.8~7.5, 5.8~7.6, 5.8~7.7, 5.8~8.0, 5.8~9.0, 5.8~9.5, 6.0~6.2, 6.0~6.5, 6.0~6.8, 6.0~7.0, 6.0~7.2, 6.0~7.3, 6.0~7.5, 6 0~7.6, 6.0~7.7, 6.0~8.0, 6.0~9.0, 6.0~9.5, 6.2~6.5, 6.2~6.8, 6.2~7.0, 6.2~7.2, 6.2~7.3, 6.2~7.5, 6.2~7.6, 6.2~7.7, 6.2~8.0, 6.2~9.0, 6.2~9. 5, 6.5~6.8, 6.5~7.0, 6.5~7.2, 6.5~7.3, 6.5~7.5, 6.5~7.6, 6.5~7.7, 6.5~8.0, 6.5~9.0, 6.5~9.5, 6.8~7.0, 6.8~7.2, 6.8~7.3, 6.8~7.5, 6.8~7.6, 6.8 ~7.7, 6.8~8.0, 6.8~9.0, 6.8~9.5, 7.0~7.2, 7.0~7.3, 7.0~7.5, 7.0~7.6, 7.0~7.7, 7.0~8.0, 7.0~9.0, 7.0~9.5, 7.2~7.3, 7.2~7.5, 7.2~7.6, 7.2~7.7 7.2~8.0, 7.2~9.0, 7.2~9.5, 7.3~7.5, 7.3~7.6, 7.3~7.7, 7.3~8.0, 7.3~9.0, 7.3~9.5, 7.5~7.6, 7.5~7.7, 7.5~8.0, 7.5~9.0, 7.5~9.5, 7.6~7.7, 7.6~8.0、7.6～9.0、7.6～9.5、7.7～8.0、7.7～9.0、7.7～9.5、8.0～9.0、8.0～9.5、9.0～9.5。.

[0069] In the entropy alloy brazing filler metal of this invention, the weight percentage of Co can specifically be 2.0, 2.2, 2.4, 2.5, 3.0, 3.5, 3.6, 3.8, 4.0, 4.5, 4.8, 5.0, 5.5, 6.0, 6.5, 7.5, 8.0, or 8.5; or any value within the range of the above two, selected from: 2.0–2.2, 2.0–2.4, 2.0–2.5, 2.0–3.0, 2.0–3.5, 2.0–3.6, 2.0–3.8, 2.0–4.0, 2.0–4.5, 2.0–4.8, 2.0–5.0, 2.0–5.5, 2.0–6.0, 2.0–6.5, 2.0–7.5, 2.0–8.0, or 2.0–8.5. 2.2~2.4, 2.2~2.5, 2.2~3.0, 2.2~3.5, 2.2~3.6, 2.2~3.8, 2.2~4.0, 2.2~4.5, 2.2~4.8, 2.2~5.0, 2.2~5.5, 2.2~6.0, 2.2~6.5, 2.2~7.5, 2.2~8.0, 2.2~ 8.5, 2.4~2.5, 2.4~3.0, 2.4~3.5, 2.4~3.6, 2.4~3.8, 2.4~4.0, 2.4~4.5, 2.4~4.8, 2.4~5.0, 2.4~5.5, 2.4~6.0, 2.4~6.5, 2.4~7.5, 2.4~8.0, 2.4~8.5, 2 0.5~3.0, 2.5~3.5, 2.5~3.6, 2.5~3.8, 2.5~4.0, 2.5~4.5, 2.5~4.8, 2.5~5.0, 2.5~5.5, 2.5~6.0, 2.5~6.5, 2.5~7.5, 2.5~8.0, 2.5~8.5, 3.0~3.5, 3.0~3. 6, 3.0~3.8, 3.0~4.0, 3.0~4.5, 3.0~4.8, 3.0~5.0, 3.0~5.5, 3.0~6.0, 3.0~6.5, 3.0~7.5, 3.0~8.0, 3.0~8.5, 3.5~3.6, 3.5~3.8, 3.5~4.0, 3.5~4.5, 3.5 ~4.8, 3.5~5.0, 3.5~5.5, 3.5~6.0, 3.5~6.5, 3.5~7.5, 3.5~8.0, 3.5~8.5, 3.6~3.8, 3.6~4.0, 3.6~4.5, 3.6~4.8, 3.6~5.0, 3.6~5.5, 3.6~6.0, 3.6~6.5 3.6~7.5, 3.6~8.0, 3.6~8.5, 3.8~4.0, 3.8~4.5, 3.8~4.8, 3.8~5.0, 3.8~5.5, 3.8~6.0, 3.8~6.5, 3.8~7.5, 3.8~8.0, 3.8~8.5, 4.0~4.5, 4.0~4.8, 4.0~5.0, 4.0~5.5, 4.0~6.0, 4.0~6.5, 4.0~7.5, 4.0~8.0, 4.0~8.5, 4.5~4.8, 4.5~5.0, 4.5~5.5, 4.5~6.0, 4.5~6.5, 4.5~7.5, 4.5~8.0, 4.5~8.5, 4.8~5.0, 4.8~5.5, 4.8~6.0, 4.8~6.5, 4.8~7.5, 4.8~8.0, 4.8~8.5 5.0~5.5, 5.0~6.0, 5.0~6.5, 5.0~7.5, 5.0~8.0, 5.0~8.5, 5.5~6.0, 5.5~6.5, 5.5~7.5, 5.5~8.0, 5.5~8.5, 6.0~6.5, 6.0~7.5, 6.0~8.0, 6.0~8.5, 6.5~7.5, 6.5~8.0, 6.5~8.5, 7.5~8.0, 7.5~8.5, 8.0~8.5.

[0070] The solder composition of the present invention can be selected from combinations within the above range.

[0071] According to the present invention, the preferred weight percentage of the solder composition is:

[0072] Ti: 9.5~13.0; Ni: 5.5~9.0; Cu: 5.0~9.5; Co: 3.0~8.0; Hf: 0.0~2.0; Zr: balance.

[0073] In some embodiments of the present invention, the preferred weight percentage of the solder composition is:

[0074] Ti: 9.5; Ni: 6.8; Cu: 7.5; Co: 5.0; Hf: 0.0; Zr: balance.

[0075] In some embodiments of the present invention, the preferred weight percentage of the solder composition is:

[0076] Ti: 12.5; Ni: 5.8; Cu: 9.5; Co: 2.0; Hf: 0.6; Zr: balance.

[0077] In some embodiments of the present invention, the preferred weight percentage of the solder composition is:

[0078] Ti: 13.7; Ni: 8.5; Cu: 9; Co: 2.2; Hf: 0.6; Zr: balance.

[0079] The liquidus temperature of the brazing filler metal described in this invention is 769℃~782℃.

[0080] This invention discovers that the combined use of Ni, Cu, and Co elements to reduce melting point is much better than using Cu, Ni, and Co alone, or any two of them together. The actual liquidus temperature of the brazing filler metal is between 769℃ and 782℃, which is applicable to a wide range of titanium alloy base materials and allows for a wide range of brazing temperatures.

[0081] In some embodiments, the titanium-containing material may include, but is not limited to: a ribbed panel structure made of pure titanium material and / or titanium alloy material; a thin-walled structure made of pure titanium material and / or titanium alloy material; a sandwich structure made of pure titanium material and / or titanium alloy material; or any structure of titanium alloy-titanium alloy. The brazing filler metal is one or more of the following shapes of medium-entropy alloy brazing filler metal: amorphous foil strip, powder, alloy block, or powder sintered body.

[0082] This invention patent application incorporates six constituent elements. Zr, Ti, and Hf are three elements that are infinitely miscible with each other, exhibiting no tendency to form brittle intermetallic compounds. Simultaneously, Ni, Cu, and Co are added to the solder alloy as melting point reducing elements. Through the principles of ternary low-melting-point eutectics such as Cu-Ni-Zr, Cu-Ni-Ti, and Cu-Ti-Zr, as well as binary low-melting-point eutectics such as Co-Ti and Co-Zr, they collectively lower the melting point of the solder alloy. Furthermore, thermodynamic calculations show that the mixing entropy ΔS of the six-element solder alloy of this invention... mix (J.K.) -1 mol -1 The value is between 9.72 and 11.32, satisfying the thermodynamic condition ΔS for high-entropy alloys. mix The value falls within the range of 1.0R-1.5R, indicating that it belongs to the medium-entropy alloy brazing filler metal. Therefore, it can play a good role in strengthening and toughening in brazed joints of pure titanium and pure titanium combined with titanium alloy.

[0083] This invention provides a method for preparing Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy solder, comprising:

[0084] A) Prepare alloy ingots by smelting metal raw materials;

[0085] B) Prepare medium-entropy alloy brazing filler metal from alloy ingots; the shape of the medium-entropy alloy brazing filler metal includes one of the following: amorphous foil strip, powder, alloy block, and powder sintered body.

[0086] The present invention first prepares alloy ingots by melting metal raw materials.

[0087] Use high-purity Zr, Ti, Ni, Cu, Co, and Hf elements with a purity of 99.5%-99.9%, and weigh them according to the weight ratio; or use high-purity Zr containing 1%-2.5% Hf element, add Hf element to the raw materials required for solder by adding high-purity Zr containing a certain amount of Hf element, and add pure Hf separately according to the insufficient Hf content in the required composition, while keeping the purity of other elements unchanged.

[0088] This invention preferably uses an electric arc melting method under inert gas protection to melt raw materials into alloy ingots. Recommended parameters for electric arc melting are: vacuuming the melting chamber to 2×10⁻⁶. -1 After Pa, purge with argon to standard atmospheric pressure, use an arc ignition current of 80A, a stable melting current of 200A, and a melting time of 13–25s. To ensure uniform alloy composition, it is recommended to melt 2–4 times.

[0089] Medium-entropy alloy brazing filler metal was prepared from alloy ingots.

[0090] In some embodiments of the present invention, one or more of the following steps are specifically included:

[0091] i) The alloy ingot is prepared into alloy powder brazing filler metal using argon atomization or plasma rotating electrode atomization. The specific parameters for argon atomization in this invention include: in an inert gas environment of argon or helium, the rod is held in a clamp and placed in a conical induction coil; the conical induction coil has a height of 500-700 mm, a lower diameter of 40-65 mm, and a cone angle of 40-65°; the power supply for providing current to the induction coil has a power of 10-23 KW and a frequency of 3500 Hz; the rod feed speed is 2.0-4.5 mm / s; and the atomization pressure is 2.0-6.5 MPa.

[0092] The specific parameters of the plasma rotating electrode atomization method of the present invention include: the diameter of the brazing master alloy rod is 30-60 mm, the rotation speed is 20000-35000 r / min, and the feeding speed is 2-5 mm / min.

[0093] ii) The alloy ingot is processed into amorphous alloy foil brazing filler metal using a single-roller rapid quenching method. The specific parameters of the single-roller rapid quenching method of the present invention include: in an inert gas protection state of argon or helium, the bar is placed in a quartz crucible, and the quartz tube crucible is placed in a ring induction coil; the height of the induction coil is 300-600 mm, and the width of the lower end of the tube is 30-50 mm; the bar feed speed is 0.2-0.5 m / s; the single-roller speed is 1300-1800 r / min; and the injection pressure is 50-70 kPa.

[0094] iii) Mechanically crush the alloy ingot to obtain a brazing alloy block;

[0095] The specific parameters for mechanical crushing in this invention include: manually striking the brazing filler alloy with a 10kg to 30kg hammer until it is crushed; or using processing methods such as wire cutting for crushing.

[0096] iv) First, prepare powdered brazing filler metal according to the above method, and then press and sinter it to obtain a sintered brazing filler metal body.

[0097] The pressing and sintering process described in this invention specifically includes: brazing filler metal powder with a particle size of -150 mesh, pressing pressure of 60-80 kN, and sintering in a vacuum furnace with a vacuum degree of 8×10⁻⁶. -3 Pa, temperature 730~750℃, holding time 20~40min.

[0098] This invention provides the application of the Zr-Ti-Hf-Ni-Cu-Co hexa-entropy alloy brazing filler metal described in any one of the above-mentioned claims in the brazing of pure titanium and / or titanium alloys.

[0099] The Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal of the present invention can be used not only for brazing between pure titanium and pure titanium, and between pure titanium and titanium alloys, but also for brazing between titanium alloys, and can achieve good results.

[0100] This invention provides a brazing method for pure titanium / or titanium alloys, comprising the following steps:

[0101] a) Material preparation: Prepare the base material of pure titanium and / or titanium alloy to be welded, and after pretreatment, obtain the pretreated base material;

[0102] b) Add brazing filler metal to the surface of the pretreated base material to be welded to obtain the assembled component;

[0103] c) Brazing the assembled components yields the final product.

[0104] The pure titanium / or titanium alloy mentioned above in this invention includes pure titanium-pure titanium, pure titanium-titanium alloy, and titanium alloy-titanium alloy.

[0105] The brazing method for pure titanium / or titanium alloys provided by this invention first includes material preparation.

[0106] The base material of pure titanium and / or titanium alloy to be welded is prepared and pretreated to obtain pretreated base material; the pretreatment specifically involves removing oxides, oils or surface contaminants from the surface of the base material; the present invention does not limit the specific removal method, but any method known to those skilled in the art is acceptable.

[0107] A solder is added to the surface of the pretreated base material to be welded to obtain an assembled component; the solder is the solder described in the above technical solution or the solder prepared by the preparation method described in the above technical solution.

[0108] Preferably, the brazing gap between the substrates to be brazed is controlled to be 0.01 to 0.08 mm by using tooling fixtures.

[0109] This invention does not limit how the above-mentioned tooling fixture controls the brazing gap; any method known to those skilled in the art is acceptable.

[0110] The assembled components are then brazed to obtain the final product.

[0111] The assembled components are placed in a vacuum brazing furnace, with a vacuum level of not less than 1×10⁻⁶. -3 Pa.

[0112] The brazing temperature is selected based on the phase transformation temperature of the base material.

[0113] In some embodiments of the present invention, the brazing temperature is specifically as follows:

[0114] When the substrate contains pure titanium, the brazing temperature T b The temperature range is 810℃~860℃.

[0115] When the matrix is ​​entirely titanium alloy, then T b The phase transformation temperature shall not exceed that of the corresponding titanium alloy. The phase transformation temperature of this invention is the transition temperature between the α and β phases of the titanium alloy.

[0116] When the substrate being welded is TC16 or TC18 titanium alloy, the brazing temperature T b The temperature range is 810℃~828℃.

[0117] When the matrix is ​​a TA18 or TA2 titanium alloy with a phase transformation temperature higher than 840℃, the brazing temperature T b The temperature is set to 810℃~830℃, or 810℃~860℃. When the substrate is TC4 titanium alloy, the brazing temperature T... b It can be set to: 810℃~890℃.

[0118] The brazing method described in this invention is vacuum brazing or induction heating brazing;

[0119] In some embodiments of the present invention, the vacuum brazing parameters are specifically: the vacuum degree inside the furnace is not less than 1×10⁻⁶. -3 Pa, heating at a rate of 20–40 °C / min to 500 °C; then continuing to heat at a rate of 15–25 °C / min to T b Hold the temperature for 10 to 30 minutes; then cool down at a rate of 15 to 25°C / min until the furnace reaches room temperature.

[0120] In some embodiments of the present invention, the induction heating brazing parameters are specifically as follows: under inert gas conditions, heating at a heating rate of 50°C / min to 100°C / min to Tb Keep warm for 1 to 10 minutes, then stop induction heating and allow to cool naturally to room temperature.

[0121] The brazing filler metal of this invention employs a balanced method of reducing melting point using Ni, Cu, and Co elements. This effectively avoids the tendency to form strong brittle intermetallic compounds in the brazed joint due to excessive addition of any single element, which is undesirable when relying solely on one element for melting point reduction. Using the brazing filler metal of this invention, brazed joints obtained under suitable brazing process conditions exhibit both good strength and ductility. The brazing filler metal of this invention demonstrates extremely strong wetting, spreading, and gap-filling capabilities in pure titanium and titanium alloy matrices during brazing.

[0122] This invention provides a Zr-Ti-Hf-Ni-Cu-Co hexavalent medium-entropy alloy brazing filler metal, wherein the weight percentage composition of the filler metal is: Ti: 9.5–13.9; Ni: 5.5–9.5; Cu: 5.0–9.5; Co: 2.0–8.5; Hf: 0.0–2.0; Zr: balance. This invention has the following technical advantages: the liquidus temperature of the filler metal is between 769℃ and 782℃, the filler metal is easily formed into an amorphous alloy, and the shear strength of the pure titanium-titanium alloy joint obtained by holding at a brazing temperature of 810℃–828℃ for 10 minutes reaches 243–280 MPa.

[0123] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0124] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a brazing filler metal, its preparation method, and its brazing method.

[0125] Examples 1-33:

[0126] 1. Selection of raw materials:

[0127] Use high-purity Zr, Ti, Ni, Cu, Co, and Hf elements with a purity of 99.5%-99.9%, and weigh them according to the weight ratio in Table 1; or use high-purity Zr containing 1%-2.5% Hf element, add Hf element to the raw materials required for solder by using high-purity Zr containing a certain amount of Hf element, and add pure Hf separately according to the insufficient Hf content in the required composition, while keeping the purity of other elements unchanged.

[0128] 2. Preparation of solder:

[0129] Under inert gas protection, the raw materials are melted into alloy ingots using an electric arc melting method. To ensure uniform alloy composition, it is recommended to melt 2-4 times. The brazing filler metal is prepared using one or more of the following methods: the alloy ingot is prepared into alloy powder brazing filler metal using argon atomization powdering or plasma rotating electrode atomization; the alloy ingot is prepared into amorphous alloy foil brazing filler metal using a single-roll rapid quenching method; and the alloy ingot is mechanically crushed to obtain brazing filler metal alloy blocks.

[0130] 3. Brazing:

[0131] (1) Material preparation: Prepare the base material of pure titanium or titanium alloy to be welded, and remove oxides, oil or surface deposits from the surface of the base material.

[0132] (2) Assembly: Apply one or two forms of brazing filler metal as described in claim 4 to the surface of the base material to be welded; place the assembled component into a vacuum brazing furnace, wherein the vacuum degree inside the furnace is not less than 1×10 -3 Pa.

[0133] (3) Brazing process: The brazing gap between the interfaces to be joined is controlled within the range of 0 to 0.1 mm using tooling fixtures. The brazing temperature is selected based on the phase transformation temperature of the base material. When the base material contains pure titanium, the brazing temperature T is... b The temperature range is 810℃-860℃; when the matrix is ​​entirely titanium alloy, then T b The temperature should not exceed the phase transformation temperature of the corresponding titanium alloy. If vacuum brazing is used, the temperature should be increased at a rate of 20-40℃ / min to 500℃; then increased again at a rate of 15-20℃ / min to T. b Hold at that temperature for 10-30 minutes; then cool down at a rate of 15-25℃ / min until room temperature is reached in the furnace. If induction brazing is used, heat to T at a rate of 50℃ / min-100℃ / min. b Keep warm for 1 to 10 minutes, then stop induction heating and allow to cool naturally to room temperature.

[0134] Table 1 Examples of solder composition

[0135]

[0136]

[0137] Regarding the Zr-Ti-Hf-Ni-Cu-Co solder and its application method, the weight percentage composition of the solder is as follows: Ti: 9.5–13.9; Ni: 5.5–9.5; Cu: 5.0–9.5; Co: 2.0–8.5; Hf: 0.0–2.0; Zr: balance. The liquidus temperature of the solder is between 769℃ and 782℃.

[0138] Using the components of the brazing filler metal in Examples 1-33, the following steps were performed: (1) Brazing filler metal preparation: The alloy raw materials used to prepare the brazing filler metal were melted into alloy ingots. Then, the brazing filler metal was prepared using one or more of the following methods: a) The alloy ingot was prepared into alloy powder brazing filler metal by argon atomization powder preparation method or plasma rotating electrode atomization method; b) The alloy ingot was prepared into amorphous alloy foil brazing filler metal by single-roller rapid quenching method; c) The alloy ingot was mechanically crushed to obtain brazing filler metal alloy blocks; d) Alloy brazing filler metal powder was prepared first according to the above method, and then pressed and sintered to prepare the required brazing filler metal sintered body.

[0139] (2) The base material is a combination of TA2-TA2, TA2-TA18, and TA2-TC4 materials. TA2 is industrial pure titanium; the nominal composition of TA18 is Ti-3Al-2.5V (weight percentage); and the nominal composition of TC4 is Ti-6Al-4V (weight percentage). The amorphous alloy foil strip is cut into the required shape and fixed to one side of the above material combinations by resistance spot welding. The brazing gap is 0.01-0.08mm.

[0140] (3) Place the assembled components into a vacuum brazing furnace, with a vacuum level of 4.5 × 10⁻⁶. -3 Pa, select an appropriate brazing temperature. When the substrate being welded is TC16 or TC18 titanium alloy, the brazing temperature T is... b The brazing temperature is 810℃-828℃. However, when the entire substrate is a titanium alloy with a phase transformation temperature higher than 840℃, the brazing temperature T is... b The temperature can be 810℃-828℃, or the brazing temperature T can be appropriately increased. b However, it should not exceed the phase transformation temperature of the corresponding titanium alloy. When the entire matrix is ​​a titanium alloy with a phase transformation temperature higher than 840℃, the brazing temperature T... b The temperature can be 810℃-828℃, or the brazing temperature T can be appropriately increased. b However, it should not exceed the phase transformation temperature of the corresponding titanium alloy. When the matrix contains pure titanium, the brazing temperature T... b You can choose any temperature within the range of 810℃ to 860℃.

[0141] The brazing effects of Examples 1-33 are as follows: For brazing pure titanium and combinations of pure titanium and titanium alloys, the amorphous alloy foil strip of the present invention, at a brazing temperature of 850-865℃ and a holding time of 18-25 minutes, achieved a comprehensive effect combining high strength and good ductility: the tensile strength of TA2-TC4 and TA2-TA18 brazed joints at room temperature was above 530 MPa, while the elongation of the two joints reached above 10% and 12% respectively, achieving a strong-ductility match. Simultaneously, the shear strength of TA2-TA18, TA2-TC16, and TA2-TC18 joints obtained by brazing at 810-828℃ reached 243 MPa-280 MPa at room temperature. By selecting an appropriate holding time, high-quality welding of TC16-TC16 and TC18-TC18 titanium alloy substrates was achieved.

[0142] Table 2 shows the brazed joint performance corresponding to Examples 1-33 in Table 1.

[0143]

[0144]

[0145] The alloy ingot was prepared into alloy powder brazing filler metal by argon atomization powder preparation method or plasma rotating electrode atomization method. Using the brazing filler metal composition of Examples 1-33, the same brazing effect with comparable joint performance was also obtained.

[0146] In addition, using the brazing filler metal composition of Examples 1-33, good welding of all the above-mentioned combined materials was also achieved by induction heating brazing.

[0147] It should be noted that the above process operations can be combined to varying degrees. For the sake of brevity, the implementation methods of various combinations will not be elaborated here. Those skilled in the art can flexibly adjust the order of the above operation steps or flexibly combine the above steps according to actual needs.

[0148] The above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the scope of protection of the present invention. The specific embodiments described in the present invention may have different formulations, process names, etc. All equivalent or simple variations made based on the structure, features, and principles described in the patent concept of the present invention are included within the patent protection scope of the present invention.

Claims

1. A Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy solder, characterized in that, The weight percentage of the solder components is: Ti: 9.5~13.9; Ni: 5.5~9.5; Cu: 5.0~9.5; Co: 2.0~8.5; Hf: 0.0~0.6; Zr: balance.

2. The brazing filler metal according to claim 1, characterized in that, The weight percentage of the solder components is: Ti: 9.5~13.0; Ni: 5.5~9.0; Cu: 5.0~9.5; Co: 3.0~8.0; Hf: 0.0~0.6; Zr: balance.

3. The brazing filler metal according to claim 1, characterized in that, The liquidus temperature of the brazing filler metal is 769℃~782℃; The brazing filler metal is one or more of the following medium-entropy alloy brazing filler metals in the form of: amorphous foil strip, powder, alloy block, or powder sintered body.

4. A method for preparing a Zr-Ti-Hf-Ni-Cu-Co entropy alloy solder, characterized in that, include: A) Prepare alloy ingots by smelting metal raw materials; B) Prepare medium-entropy alloy brazing filler metal from alloy ingots; The shape of the medium-entropy alloy brazing filler metal includes one of the following: amorphous foil strip, powder, alloy block, and powder sintered body.

5. The preparation method according to claim 4, characterized in that, Step B) specifically includes one or more of the following steps: i) The alloy ingot is prepared into alloy powder brazing filler metal by argon atomization powder preparation method or plasma rotating electrode atomization method; ii) The alloy ingot is processed into amorphous alloy foil brazing filler metal using a single-roll rapid quenching method; iii) Mechanically crush the alloy ingot to obtain a brazing alloy block; iv) First, prepare powdered brazing filler metal according to the above method, and then press and sinter it to obtain a sintered brazing filler metal body.

6. The application of the Zr-Ti-Hf-Ni-Cu-Co medium-entropy alloy brazing filler metal according to any one of claims 1 to 3 in brazing pure titanium and / or titanium alloys.

7. A brazing method for pure titanium and / or titanium alloys, characterized in that, Includes the following steps: a) Material preparation: Prepare the base material of pure titanium and / or titanium alloy to be welded, and obtain the pretreated base material after pretreatment; b) Add brazing filler metal to the surface of the pretreated base material to be welded to obtain the assembled component; the brazing filler metal is the brazing filler metal according to any one of claims 1 to 3 or the brazing filler metal prepared by the preparation method according to any one of claims 4 to 5; c) Brazing the assembled components yields the final product.

8. The brazing method according to claim 7, characterized in that, The pretreatment step a) specifically involves removing oxides, oils, or surface contaminants from the surface of the base material; Step b) also includes machining and controlling the brazing gap between the substrates to be brazed to be 0.01 to 0.08 mm using tooling fixtures.

9. The brazing method according to claim 7, characterized in that, The brazing temperature in step c) is specifically: When the substrate contains pure titanium, the brazing temperature T b The temperature range is 810℃~860℃. When the substrate being welded is TC16 or TC18 titanium alloy, the brazing temperature T b The temperature range is 810℃~828℃. When the substrate is a titanium alloy with a phase transformation temperature higher than 840℃, the brazing temperature T b The temperature range is 810℃~828℃, or 10℃ lower than the phase transformation temperature of the titanium alloy base material.

10. The brazing method according to claim 9, characterized in that, The brazing method described in step c) is vacuum brazing or induction heating brazing; The specific vacuum brazing parameters are: the vacuum level inside the furnace is not less than 1×10⁻⁶. -3 Pa, heating at a rate of 20–40 °C / min to 500 °C; then continuing to heat at a rate of 15–25 °C / min to T b Hold the temperature for 10 to 25 minutes; then cool down at a rate of 15 to 25°C / min until the furnace reaches room temperature. The specific parameters for induction heating brazing are: vacuum degree below 2×10⁻⁶. -1 Inert gas is introduced to a pressure of 70–100 kPa, and then heated to T at a heating rate of 50–100 °C / min under inert gas conditions. b Keep warm for 1 to 10 minutes, then stop induction heating and allow to cool naturally to room temperature.

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