A titanium-based alloy, a titanium-based filler metal and a preparation method thereof

Abstract

The present invention discloses a titanium-based alloy, a titanium-based filler metal and a preparation method thereof, belonging to the technical field of brazing applications, and solving the problems of large brittleness and low strength of the brazed joints of the existing titanium-based filler metals. In terms of mass percentage content, the titanium-based alloy includes: Zr, 5% - 30%, Cu, 10% - 15%, Ni, 10% - 15%, Nb, 0.5% - 3.5%, rare earth elements, 0.1% - 0.3%; the balance is Ti and inevitable trace impurities; the rare earth elements include one or more of La, Ce and Y.

Description

Technical Field

[0001] The present invention relates to the technical field of brazing applications, and particularly relates to a titanium-based alloy, a titanium-based filler metal and a preparation method thereof. Background Art

[0002] As an important joining method, brazing technology is widely used in fields such as aerospace, electronics, and automotive manufacturing. Titanium and its alloys have been widely used in modern industry due to their excellent strength, corrosion resistance, and specific strength. However, brittle phases are easily generated during the brazing process of titanium alloy materials, which affects the mechanical properties of the joints. Especially at high temperatures, they exhibit greater brittleness, which severely limits the application scope of titanium and its alloys.

[0003] The filler metal systems for traditional titanium alloy brazing mainly consist of elements such as Ti, Zr, Cu, and Ni. A large amount of elements such as Zr, Al, V, Cu, and Ni are prone to form brittle compounds during the brazing process, resulting in insufficient strength and toughness of the brazed joints. When brazing titanium alloys, brittle compound phases such as Ti3Al, Ti-V, Ti2Ni, TiNi, and TiCu will form at the interface, which has an adverse effect on the fracture toughness and fatigue performance of the joints. Generally, the brazed specimens show brittle fracture, and the elongation after fracture < 5%. Although the performance of the brazed joints can be improved to a certain extent by optimizing the brazing process, due to the limitations of the filler metal itself, the existing titanium-based filler metals are still difficult to meet some application scenarios with high requirements for joint performance. Summary of the Invention

[0004] In view of the above situation, the present invention aims to provide a titanium-based alloy, a low-brittle titanium-based filler metal and a brazing method to solve the problems of large brittleness and low strength of the brazed joints using the existing titanium-based filler metals.

[0005] The object of the present invention is mainly achieved through the following technical solutions:

[0006] In the first aspect, the present invention provides a titanium-based alloy, calculated by mass percentage, including: Zr, 5% - 30%, Cu, 10% - 15%, Ni, 10% - 15%, Nb, 0.5% - 3.5%, rare earth elements, 0.1% - 0.3%; the balance is Ti and inevitable trace impurities.

[0007] Optionally, the rare earth elements include one or more of La, Ce, and Y.

[0008] Optionally, calculated by mass percentage, the titanium-based alloy includes: Zr, 15% - 25%, Cu, 12% - 15%, Ni, 12% - 15%, Nb, 2% - 3%, rare earth elements, 0.1% - 0.3%; the balance is Ti and inevitable trace impurities.

[0009] In a second aspect, the present invention also provides a low-brittle titanium-based filler metal, which includes the above-mentioned titanium-based alloy.

[0010] Optionally, the melting point of the titanium-based filler metal is 820 - 878 °C.

[0011] Optionally, the thickness of the titanium-based filler metal is 0.02 - 0.04 mm, and the width is 40 - 100 mm.

[0012] In a third aspect, the present invention also provides a method for preparing the above-mentioned low-brittle titanium-based filler metal, which includes the following steps:

[0013] Step 1: Melting the above-mentioned titanium-based alloy into an alloy ingot;

[0014] Step 2: Preparing the alloy ingot into a titanium-based filler metal through a vacuum rapid quenching process.

[0015] Optionally, in Step 1, the melting temperature is 1200 - 1400 °C.

[0016] Optionally, in Step 2, the vacuum rapid quenching process is carried out in a vacuum rapid quenching device.

[0017] Optionally, the vacuum rapid quenching device includes a melting furnace vacuum chamber, a rapid quenching vacuum chamber, and a vacuum storage bin arranged in sequence; a rotating cooling roll is provided in the rapid quenching vacuum chamber, and the rotating cooling roll has a spindle-shaped internal space, and a cooling medium flows through the spindle-shaped internal space.

[0018] Optionally, a turntable tundish system, a strip guiding cooling roll, and a strip anti-accumulation track are also provided in the rapid quenching vacuum chamber, and the rotating cooling roll, the turntable tundish system, the strip guiding cooling roll, and the strip anti-accumulation track are arranged in sequence.

[0019] Optionally, a melting device is provided in the melting furnace vacuum chamber, and a melting crucible is provided in the melting device.

[0020] Optionally, the melting device is an intermediate frequency melting furnace.

[0021] Optionally, the turntable tundish system includes a plurality of rotatable tundishes, and the rotating cooling roll is arranged below the tundishes.

[0022] Optionally, a nozzle is provided below the tundish to spray a cooling medium onto the rotating cooling roll.

[0023] Optionally, the number of the tundishes is 3 - 5.

[0024] Optionally, the capacity of the tundish is 25 - 100 kg.

[0025] Optionally, it further includes an on-line instant grinding device, and the on-line instant grinding device is arranged towards the working surface of the rotary cooling roller.

[0026] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0027] a) By adding rare earth elements to the titanium-based alloy, the present invention forms high-melting-point compounds through the internal oxidation of rare earth elements, reduces the oxygen content of the matrix, and improves the high-temperature oxidation resistance and mechanical properties of the alloy. The rare earth elements enhance the mechanical properties of the titanium alloy in the form of solid solution and formation of intermetallic compounds. Introducing rare earth elements provides an effective way to optimize the performance of the titanium-based filler metal. While improving the strength (tensile strength of the brazed joint is 930 - 950 MPa) and toughness of the brazed joint, it reduces the brittleness of the brazed joint (elongation after fracture is 11% - 15%, much higher than the elongation after fracture < 5% of the prior art), broadens the application range of titanium and its alloys, and enables them to be applied to occasions with higher requirements for joint performance.

[0028] b) The present invention selects the rare earth elements as La, Ce, and Y, which is convenient for the rare earth elements to dissolve in other elements in the titanium-based alloy and is easier to form intermetallic compounds, thus ensuring the enhancement of the mechanical properties of the titanium-based alloy. Moreover, since the prices of La, Ce, and Y are lower than those of other rare earth elements, it is beneficial to reduce the production cost.

[0029] c) In the preparation method of the filler metal of the present invention, a vacuum rapid quenching device with strong and uniform cooling intensity is adopted, and the yield of preparing the titanium-based filler metal (amorphous strip) from the titanium-based alloy is increased from about 50% to more than 80%.

[0030] Other features and advantages of the present invention will be described in the following specification, and some of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the written specification and the accompanying drawings. Description of the Drawings

[0031] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs represent the same components.

[0032] Figure 1 It is the morphology of the amorphous filler metal strip obtained in Example 1;

[0033] Figure 2 It is the fracture diagram of the tensile specimen for the tensile strength test of the brazed joint in Example 1;

[0034] Figure 3 It is the tensile stress-strain curve for the tensile strength test of the brazed joint in Example 1;

[0035] Figure 4 It is the typical microstructure of the brazed joint in Example 1;

[0036] Figure 5 It is the morphology of the amorphous filler metal strip obtained in Example 2;

[0037] Figure 6 It is the fracture diagram of the tensile specimen for the tensile strength test of the brazed joint in Example 2;

[0038] Figure 7 It is the tensile stress-strain curve of the tensile strength test of the brazed joint in Example 2;

[0039] Figure 8 It is the typical microstructure of the brazed joint in Example 2;

[0040] Figure 9 It is the morphology of the amorphous filler metal strip obtained in Example 3;

[0041] Figure 10 It is the fracture diagram of the tensile specimen for the tensile strength test of the brazed joint in Example 3;

[0042] Figure 11 It is the tensile stress-strain curve of the tensile strength test of the brazed joint in Example 3;

[0043] Figure 12 It is the typical microstructure of the brazed joint in Example 3;

[0044] Figure 13 It is the schematic diagram of the structure of the rotating cooling roll of the present invention;

[0045] Figure 14-1 It is the velocity contour map (longitudinal section) of the flow field when the core barrel of the rotating cooling roll of the present invention rotates;

[0046] Figure 14-2 It is the velocity contour map (longitudinal section) of the flow field when the core barrel of the rotating cooling roll of the present invention follows;

[0047] Figure 15-1 It is the velocity vector map (longitudinal section) of the flow field when the core barrel of the rotating cooling roll of the present invention rotates;

[0048] Figure 15-2 It is the velocity vector map (longitudinal section) of the flow field when the core barrel of the rotating cooling roll of the present invention follows;

[0049] Figure 16 It is the schematic diagram of the structure of the vacuum rapid quenching equipment of the present invention.

[0050] Reference numerals:

[0051] 1 - Rotating shaft; 2 - Flange; 3 - Cooling copper sleeve; 4 - Core barrel; 5 - Rotary dynamic seal; 6 - Rolling bearing; D - Width of spiral groove; h - Height of spiral groove; 7 - Vacuum chamber of melting furnace; 8 - Melting device; 9 - Quick - quenching vacuum chamber; 10 - Vacuum silo; 11 - On - line instant grinding device; 12 - Rotating cooling roller; 13 - Turntable - type tundish system; 14 - Strip guiding cooling roller; 15 - Strip anti - accumulation track. Detailed implementation mode

[0052] The following will specifically describe the preferred embodiments of the present invention in conjunction with the accompanying drawings, where the drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principles of the present invention.

[0053] In the first aspect, the present invention provides a titanium - based alloy. The components of the above - mentioned titanium - based alloy are calculated by mass percentage and include: Zr, 5% - 30%, Cu, 10% - 15%, Ni, 10% - 15%, Nb, 0.5% - 3.5%, rare earth elements, 0.1% - 0.3%; the balance is Ti and inevitable trace impurities.

[0054] Specifically, the rare earth elements of the present invention are one or several of La, Ce and Y.

[0055] The following specifically explains the functions and dosage selections of the components contained in the present invention:

[0056] Zr: The addition of Zr element can improve the fluidity of the filler metal and enhance the wettability during the brazing process, thus facilitating the formation of a uniform brazed joint. Therefore, the present invention limits the Zr content to 5% - 30%.

[0057] Cu: The Cu element plays a role in reducing the melting point and increasing the fluidity in the filler metal, helping the filler metal to better fill the joint gap, and also facilitating the diffusion of elements and the progress of phase transformation. Therefore, the present invention limits the Cu content to 10% - 15%.

[0058] Ni: The addition of Ni element can further improve the corrosion resistance and mechanical properties of the filler metal, enhancing the durability and service life of the brazed joint. Therefore, the present invention limits the Ni content to 10% - 15%.

[0059] Nb: Appropriate addition of Nb element can effectively improve the mechanical properties and corrosion resistance of the amorphous alloy, while excessive Nb element may lead to a decline in performance. Therefore, the present invention limits the Nb content to 0.5% - 3.5%.

[0060] Rare earth elements: Rare earth elements can form high-melting-point compounds through internal oxidation, reduce the oxygen content of the matrix, and improve the high-temperature oxidation resistance and mechanical properties of the alloy. In the present invention, the rare earth elements enhance the mechanical properties of the titanium alloy in the form of solid solution and formation of intermetallic compounds. Therefore, the content of rare earth elements in the present invention is limited to 0.1% - 0.3%.

[0061] Ti: The Ti element is the balance, and its content > 50%, ensuring that the filler metal composition is titanium-based.

[0062] The above-mentioned titanium-based alloy is prepared by the following method: Weigh each component according to the above ratio, and melt it under the condition of a vacuum degree < 10 -1 Pa and at a temperature of 1200 - 1400 °C, and keep it warm for 10 - 25 minutes.

[0063] In a second aspect, the present invention also provides a low-brittle titanium-based filler metal, including the above-mentioned titanium-based alloy.

[0064] In order to further improve the comprehensive performance of the above low-brittle titanium-based filler metal, the components of the above titanium-based alloy may be, by mass percentage: Zr, 15% - 25%, Cu, 12% - 15%, Ni, 12% - 15%, Nb, 2% - 3%, rare earth elements, 0.1% - 0.3%, and the balance is Ti and inevitable trace impurities.

[0065] Specifically, the microstructure of the above low-brittle titanium-based filler metal includes: At the brazing interface, Cu and Ni elements rapidly diffuse into the matrix, and Ti elements rapidly diffuse into the filler metal. First, a diffusion layer is formed near the two sides of the matrix, and it gradually becomes wider as the brazing temperature and holding time increase. Subsequently, β-Ti nucleates and grows in the liquid filler metal. At this time, the remaining liquid phase mainly contains Ti, Zr, Cu, and Ni elements, and solidifies to form (Ti,Zr) 2 (Cu,Ni) phase. As the temperature decreases, the high-temperature β-Ti gradually undergoes eutectoid decomposition to generate α-Ti distributed in lamellar form. The addition of rare earth elements and Nb elements is beneficial to the precipitation of lamellar α-Ti, reducing the volume content of brittle (Ti,Zr) 2 (Cu,Ni) phase, thereby increasing the joint toughness.

[0066] The design concept of the low-brittle titanium-based filler metal of the present invention is as follows: By adding rare earth elements to the titanium-based alloy, high-melting-point compounds are formed through internal oxidation of the rare earth elements, reducing the oxygen content of the matrix, and improving the high-temperature oxidation resistance and mechanical properties of the alloy. The rare earth elements enhance the mechanical properties of the titanium alloy in the form of solid solution and intermetallic compound formation. While increasing the strength of the brazed joint (the tensile strength of the brazed joint is 930-950 MPa) and toughness, the brittleness of the brazed joint is reduced (the elongation after fracture is 11%-15%, much higher than the elongation after fracture <5% of the prior art), broadening the application range of titanium and its alloys, enabling them to be applied to occasions with higher requirements for joint performance.

[0067] Thirdly, the present invention also provides a preparation method of a low-brittle titanium-based filler metal, including the following steps:

[0068] Step 1: Melting the above-mentioned titanium-based alloy into an alloy ingot;

[0069] Step 2: Preparing the alloy ingot into an amorphous strip, i.e., the titanium-based filler metal, through a vacuum rapid quenching process.

[0070] Specifically, in Step 1, the melting temperature is 1200-1400 °C, for example, 1200 °C, 1250 °C, 1300 °C, 1350 °C, 1400 °C.

[0071] The heat preservation time is 10-25 minutes, for example, 10 minutes, 15 minutes, 20 minutes, 25 minutes.

[0072] The vacuum degree < 10 -1 Pa, for example, 1×10 -2 Pa, 3×10 -2 Pa, 5×10 -2 Pa, 7×10 -2 Pa, 9×10 -2 Pa.

[0073] Specifically, in Step 2, in the vacuum rapid quenching process, the melting temperature is 1100-1400 °C, for example, 1100 °C, 1150 °C, 1200 °C, 1250 °C, 1300 °C, 1350 °C, 1400 °C.

[0074] The vacuum degree ≤ 10 -2 Pa, for example, 1×10 -2 Pa, 1×10 -3 Pa, 5×10 -3 Pa, 7×10 -3 Pa, 9×10 -3 Pa.

[0075] In Step 2, the vacuum rapid quenching process is carried out in a vacuum rapid quenching device. Figure 16As shown in the figure, the vacuum rapid quenching equipment includes a melting furnace vacuum chamber 7, a rapid quenching vacuum chamber 9, and a vacuum bin 10 arranged in sequence; the melting furnace vacuum chamber 7, the rapid quenching vacuum chamber 9, and the vacuum bin are independent and enclosed structures, and can, without affecting each other, communicate with the atmospheric environment and then perform corresponding operations respectively.

[0076] A melting device 8 is provided in the melting furnace vacuum chamber 7, and a melting crucible for placing the master alloy is provided in the melting device 8.

[0077] In the rapid quenching vacuum chamber 9, a rotary cooling roll 12, a rotary tundish system 13, a strip guiding cooling roll 14, and a strip anti - accumulation track 15 are arranged in sequence.

[0078] In a specific embodiment, the melting device 8 is an intermediate - frequency melting furnace. The capacity of the intermediate - frequency melting furnace is 10 - 300 kg, preferably 50 - 150 kg.

[0079] The rotary tundish system 13 is provided with 3 - 5 rotatable independent tundishes. Each independent tundish can be driven by a horizontal disk to rotate and / or stop along the circumference of the disk. The rotary cooling roll 12 is arranged below the tundish, and a nozzle is provided below each tundish to spray a cooling medium onto the rotary cooling roll 12. Exemplarily, the capacity of the tundish is 25 - 100 kg.

[0080] In a preferred embodiment, the vacuum rapid quenching equipment further includes an on - line instant grinding device 11, which is arranged facing the working surface of the rotary cooling roll 12 and can trim and polish the surface of the rotary cooling roll 12 when the melting device 8 is feeding and melting.

[0081] The strip guiding cooling roll 14 is a two - roll adjustable slit structure, which is arranged at the outlet end where the strip leaves the rotary cooling roll 12, controls the flight state of the strip after leaving the roll, guides the strip through the slit into the strip anti - accumulation track 15, and performs secondary cooling on the strip.

[0082] As Figure 13 shown, the rotary cooling roll includes a rotary shaft 1, a flange 2, a cooling sleeve 3, a core barrel 4, a rotary dynamic seal 5, and a rolling bearing 6.

[0083] The flange 2, the core barrel 4, and the cooling sleeve 3 form an internal flow path, and the cooling medium flows through this internal flow path. Figure 13 The arrows in the figure indicate the flow direction of the cooling medium.

[0084] The cooling sleeve 3 is a column without end faces and with a hollow interior. The two ends of the cooling sleeve are respectively connected to a flange 2, and the other ends of the two flanges 2 are respectively connected to the rotating shaft 1. The two flanges 2 and the cooling sleeve 3 form a spindle-shaped internal space. The core barrel 4 is arranged in the internal space formed by the flange 2 and the cooling sleeve 3, and there are gaps between the core barrel 4 and the flange 2 and the cooling sleeve 3 respectively for the cooling medium to flow through. Specifically, as Figure 13 shown, the longitudinal section of the structure formed by the flange 2 and the cooling sleeve 3 is similar to a hexagon.

[0085] The flange 2 has a conical structure with a conical angle of 40° - 70°, for example, 40°, 50°, 60°, 70°. The inner wall of the flange 2 is provided with a flow guiding groove, which can enable the cooling medium (such as water) to be quickly distributed after entering the cooling roll.

[0086] Specifically, the end of the flange 2 with a larger diameter is connected to the cooling sleeve 3, and the end with a smaller diameter is connected to the rotating shaft 1.

[0087] The core barrel 4 has a spindle-shaped sealed cavity structure, and its outer shape corresponds to the spindle-shaped internal space. The two ends of the core barrel 4 are respectively connected to the rotating shaft 1. A rolling bearing 6 is fixedly connected at the connection between the core barrel 4 and the rotating shaft 1, so that the core barrel 4 can be in a follow-up state (with water flowing) when the rotating shaft 1 and the cooling sleeve 3 rotate.

[0088] The flange 2, the core barrel 4 and the cooling sleeve 3 construct an internal flow path with a spindle-shaped streamline structure. The streamline structure design is beneficial to overcoming the centrifugal force, can reduce the influence of the centrifugal force of the high-speed rotation of the cooling roll on the cooling medium, especially the cooling medium in the annular waterway between the cooling sleeve and the core barrel, and then is beneficial to the rapid distribution of the cooling medium through the inlet and the rapid collection of the cooling medium through the internal flow path to flow out from the outlet, thereby improving the cooling intensity.

[0089] In a preferred embodiment, the longitudinal section of the core barrel 4 is similar to a hexagon.

[0090] In another embodiment, the rotating cooling roll further includes a locking member (such as a buckle) to fix the core barrel 4 to the rotating shaft 1. At this time, the core barrel 4 is in a rotating state, that is, the core barrel 4 rotates with the rotation of the rotating shaft 1. The present invention can realize the switching between the follow-up state and the rotating state of the core barrel 4 by setting the locking member, and the cooling intensities of the core barrel 4 in the follow-up state and the rotating state are different (see Table 1), thereby realizing the adjustment of the cooling intensity and expanding the application range of the rotating cooling roll of the present invention.

[0091] Specifically, the inside of the rotating shaft 1 is hollow to allow a cooling medium to flow through. The rotating shaft 1 includes two sections, one for the inflow of the cooling medium and the other for the outflow of the cooling medium. Each section of the rotating shaft is connected to the smaller-diameter end of the flange 2. One end of the rotating shaft 1 is open and the other end is closed. Through holes communicating with the outside are provided on the side wall of each section of the rotating shaft, and the through holes are provided at the gap left between the flange 2 and the core barrel 4, so as to realize the inflow or outflow of the cooling medium between the rotating shaft and the internal flow path, that is, to flow the cooling medium in the rotating shaft 1 into the internal flow path or to flow the cooling medium in the internal flow path into the rotating shaft 1, so as to realize the collection of the cooling medium flowing through the internal flow path to the outlet for outflow.

[0092] Specifically, the number of the through holes is multiple, and the multiple through holes are uniformly arranged along the circumferential direction of the rotating shaft 1.

[0093] In a preferred embodiment, a rotary dynamic seal 5 is further provided at the connection between the core barrel and the rotating shaft to prevent the cooling medium in the internal flow path from flowing into the cavity of the core barrel 4.

[0094] It should be noted that compared with the solid structure, the core barrel 4 designed as a cavity structure is beneficial to reducing the weight of the cooling roller, saving raw materials and reducing costs.

[0095] The inner wall of the cooling sleeve 3 is provided with single or multiple spiral grooves to form a spiral water channel. Preferably, it is multiple spiral grooves. For example, 3-5 mutually parallel spiral grooves. In use, the present invention controls the flow direction of the cooling medium to be opposite to the rotation direction of the cooling roller, so as to increase the cooling capacity of the system.

[0096] Specifically, the pitch S of the spiral groove is 50-100 mm. The cross-section of the spiral groove is semi-elliptical, semi-circular, triangular, rectangular or trapezoidal. When the cross-section of the spiral groove is semi-elliptical or rectangular, the ratio of the width to the height is 2-3.5. By providing spiral grooves on the inner wall of the cooling sleeve 3, the present invention can reduce the area (dead zone) where the cooling medium is relatively stationary with respect to the inner surface of the cooling roller formed by high-speed rotation when the cooling medium flows in the spiral water channel; the existence of the dead zone causes the cooling medium water to contact and vaporize on the inner surface of the cooling roller, forming a gas film, which hinders heat transfer and is prone to danger in severe cases (when the vapor pressure is too high). By providing spiral grooves on the inner wall of the cooling sleeve 3, on the one hand, the cooling intensity is improved, and on the other hand, the production safety is improved.

[0097] The material of the cooling sleeve 3 is copper, copper alloy and other materials with high thermal conductivity. The gap between the cooling sleeve 3 and the core barrel 4 is 5-10 mm on one side, for example, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm. The gap between the flange 2 and the core barrel 4 is 30-40 mm on one side, for example, 30 mm, 32 mm, 35 mm, 37 mm, 39 mm, 40 mm.

[0098] Compared with the prior art, the rotating cooling roll of the present invention has the following beneficial technical effects:

[0099] 1) The flange of the present invention has a conical structure. After being connected to the cooling sleeve without an end face and hollow inside, a spindle-shaped internal space is formed. The core barrel is a spindle-shaped sealed cavity structure, corresponding to the spindle-shaped internal space formed by the flange and the cooling roll, and there are gaps between the core barrel and the flange and the cooling sleeve respectively, thus constructing an internal flow path with a spindle-shaped streamline structure. The streamline structure design is beneficial to overcoming the centrifugal force, and can reduce the influence of the centrifugal force of the high-speed rotation of the cooling roll on the internal flow of the cooling medium, especially the cooling medium in the annular waterway between the cooling sleeve and the core barrel. Furthermore, it is beneficial for the cooling medium to be quickly distributed through the inlet and quickly converge to the outlet and flow out through the internal flow path, ensuring that the cooling medium can pass quickly. On the one hand, more heat can be carried away in a short time, achieving the purpose of efficient heat exchange, thereby improving the cooling intensity; on the other hand, the cooling uniformity can be increased, and the yield of amorphous ribbon can be increased to more than 80% (the yield of amorphous ribbon in the prior art is about 50%).

[0100] 2) By connecting a rolling bearing at the connection end of the core barrel and the rotating shaft, the present invention can make the core barrel in a follow-up state when the rotating shaft and the cooling sleeve rotate, which is equivalent to applying a shear force perpendicular to the direction of the centrifugal force to the internal cooling medium, aiming to offset part of the centrifugal force, increase the axial movement efficiency of the cooling medium, and improve the cooling intensity of the rotating cooling roll.

[0101] 3) By setting a locking member to fix the core barrel and the rotating shaft, the present invention realizes that the core barrel is in a rotating state, that is, the core barrel rotates with the rotation of the rotating shaft. And the cooling intensities of the core barrel in the follow-up state and the rotating state are different (see Table 1), thereby realizing the adjustment of the cooling intensity and expanding the application range of the rotating cooling roll of the present invention.

[0102] 4) By arranging a diversion groove on the inner wall of the flange, the present invention can realize the rapid distribution of the cooling medium, ensure that the cooling medium can pass quickly, carry away more heat in a short time, achieve the purpose of efficient heat exchange, and thus further improve the cooling intensity.

[0103] 5) By providing single or multiple spiral grooves on the inner wall of the cooling sleeve, and controlling the flow direction of the cooling medium to be opposite to the rotation direction of the cooling roll, the present invention increases the cooling capacity of the system, thereby improving the cooling intensity.

[0104] 6) The cooling roll of the present invention has good popularization and practical value. Applied to the vacuum rapid quenching equipment, it can prepare amorphous foil strips of alloy systems that are urgently needed in the aerospace field and do not have strong amorphous formation ability. After extensive popularization and application, good economic and social benefits will be generated.

[0105] 7) The rotating cooling roller in the vacuum rapid quenching equipment of the present invention constructs an internal flow path with a spindle-shaped streamline structure, which is beneficial to overcoming the centrifugal force, can reduce the influence of the high-speed rotating centrifugal force of the cooling roller on the unsmooth internal flow of the cooling medium, especially the cooling medium in the annular waterway between the cooling sleeve and the core barrel. Furthermore, it is beneficial for the cooling medium to be quickly distributed through the inlet and quickly converge to the outlet through the internal flow path, ensuring that the cooling medium can pass quickly. On the one hand, more heat can be carried away in a short time, achieving the purpose of efficient heat exchange, thereby improving the cooling intensity; on the other hand, it can increase the cooling uniformity and improve the finished product rate of the amorphous strip to more than 80% (the finished product rate of the amorphous strip in the prior art is about 50%).

[0106] The thickness of the amorphous strip prepared by the method of the present invention is 0.02 - 0.04 mm, for example, 0.02 mm, 0.03 mm, 0.04 mm. The width of the amorphous strip is 40 - 100 mm. For example, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm.

[0107] In addition, the melting point of the titanium-based brazing filler metal prepared by the above preparation method is 820 - 878 °C, for example, 820 °C, 830 °C, 840 °C, 850 °C, 860 °C, 870 °C, 878 °C.

[0108] Fourthly, the present invention also provides a brazing method using the above titanium-based brazing filler metal, including the following steps:

[0109] Step a: Place the titanium-based brazing filler metal on the surface of the component to be welded and fix it by a tooling fixture.

[0110] Step b: Place the component to be welded with the titanium-based brazing filler metal fixed in a vacuum brazing furnace, perform brazing, and keep warm.

[0111] Specifically, in step a, the material of the component to be welded is TA15 titanium alloy.

[0112] Specifically, in step b, the brazing temperature is 890 - 980 °C, for example, 890 °C, 900 °C, 910 °C, 920 °C, 930 °C, 940 °C, 950 °C, 960 °C, 970 °C, 980 °C, preferably 900 - 950 °C. The holding time is 5 - 60 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, preferably 15 - 25 min. The vacuum degree during brazing ≤ 1×10 -2 Pa, for example, 1×10 -2 Pa, 5×10-3 Pa, 7×10 -3 Pa, 9×10 -3 Pa.

[0113] By controlling the brazing temperature at 890 - 980 °C and the holding time at 5 - 60 min, the present invention can achieve both high strength and toughness at the joint interface, and thus obtain a brazing quality with low brittleness and high strength.

[0114] Examples 1 - 6

[0115] The following specific examples and comparative examples are used to demonstrate the advantages of precise control of the composition and process parameters of the low - brittleness titanium - based filler metal of the present invention.

[0116] Examples 1 - 6 of the present invention provide a low - brittleness titanium - based filler metal and its preparation method and brazing method. The chemical compositions of the filler metals in Examples 1 - 6 are shown in Table 1.

[0117] The preparation method and brazing method of the filler metals in Examples 1 - 6 include: smelting into alloy ingots, using a vacuum rapid quenching process to prepare the alloy ingots into titanium - based filler metals (amorphous ribbons), fixing the filler metals, brazing, and holding.

[0118] It should be noted that the equipment used in the vacuum rapid quenching process in Examples 1 - 6 is a vacuum rapid quenching equipment, and the rotating cooling roller in the vacuum rapid quenching equipment is the cooling roller of Example 7.

[0119] The specific process parameters of Examples 1 - 6 are shown in Table 2; the tensile strength of the brazed joints is tested, and the test results are shown in Table 3.

[0120] Table 1 Chemical composition, wt%

[0121] Example Zr Cu Ni Nb La Ce Y Ti 1 30 15 10 0.5 0.2 0 0 Balance 2 20 10 15 1 0 0.1 0 Balance 3 20 15 10 3 0 0.2 0.1 Balance 4 5 10 15 3.5 0.1 0 0 Balance 5 25 15 15 2 0 0.3 0 Balance 6 15 12 12 1.5 0 0.1 0.2 Balance

[0122] Table 2 Production process parameters

[0123]

[0124] Table 3 Partial performance test results

[0125]

[0126] Figure 1 , Figure 5 and Figure 9 are the morphologies of the amorphous filler metal ribbons obtained in Example 1, Example 2, and Example 3, respectively. As can be seen from Figure 1 , Figure 5 and Figure 9 , the ribbon - forming properties of the ribbons with the three compositions are all good, the ribbons are continuous, and there are no holes.

[0127] Figure 2 ,Figure 6 And Figure 10 are respectively the fracture diagrams of tensile specimens for tensile strength testing of the brazed joints in Example 1, Example 2, and Example 3. As can be seen from Figure 2 , Figure 6 and Figure 10 , when the three-component filler metal tapes are used for brazing titanium alloys, the corresponding brazed joints all fracture at the substrate after room-temperature tension, indicating that the brazing performance is stronger than that of the substrate.

[0128] Figure 3 (Taking 3 samples for each component), Figure 7 (Taking 3 samples for each component) and Figure 11 (Taking 3 samples for each component) are respectively the tensile stress-strain curves for tensile strength testing of the brazed joints in Example 1, Example 2, and Example 3. The average tensile strength is shown in Table 3. As can be seen from Table 3, after brazing with the filler metal of the present invention, the tensile strength of the brazed joint is greater than 930 MPa, and the elongation after fracture of the fracture is greater than 11%. While improving the strength and toughness of the brazed joint, the brittleness of the brazed joint is reduced, and the application range of titanium and its alloys is broadened, enabling it to be applied to occasions with higher requirements for joint performance.

[0129] Figure 4 , Figure 8 and Figure 12 are respectively the typical microstructures of the brazed joints in Example 1, Example 2, and Example 3. As can be seen from Figure 4 , Figure 8 and Figure 12 , the typical microstructure of the brazed joint is a lamellar structure. The proportion of the lamellar structure is shown in Table 4 below.

[0130] Table 4 Microstructure of the filler metal

[0131] Number Microstructure Proportion of microstructure Example 1 Laminar structure 75％ Example 2 Laminar structure 78％ Example 3 Laminar structure 90％

[0132] During the research process, the inventor conducted a large number of experimental studies, and now some solutions with poor performance are taken as comparative examples.

[0133] Comparative Example 1

[0134] This comparative example provides a titanium-based filler metal, whose components are similar to those in Example 2. The difference is that rare earth elements are not added. The specific components are shown in Table 5 below. The preparation method is the same as that in Example 1 and will not be elaborated here.

[0135] Comparative Example 2

[0136] This comparative example provides a titanium-based filler metal, whose components are similar to those in Example 2. The difference is that the content of rare earth elements is 0.5% (not within the range of 0.1% - 0.3%). The specific components are shown in Table 5 below. The preparation method is the same as that in Example 1 and will not be elaborated here.

[0137] Comparative Example 3

[0138] This comparative example provides a titanium-based filler metal, the components of which are the same as those in Example 2, except that the melting temperature in step 1 of the preparation method is 1000 °C (see Table 6).

[0139] The main performance test results of the comparative example titanium-based filler metal are shown in Table 7.

[0140] Table 5 Chemical composition, wt%

[0141] Comparative example Zr Cu Ni Nb La Ce Y Ti 1 20 10 15 1 0 0 0 Balance 2 20 10 15 1 0.5 0 0 Balance 3 20 10 15 1 0 0.1 0 Balance

[0142] Table 6 Production process parameters

[0143]

[0144] Table 7 Partial performance test results

[0145]

[0146] By comparing the data in Table 3 and Table 7, it can be seen that when no rare earth element is added to the filler metal, or when too many rare earth elements are added and the content is not within the range of 0.1%-0.3%, the strength of the brazed joint after brazing is only 860-870 MPa (much lower than that of the present invention which is greater than 930 MPa), and the elongation after fracture of the fracture surface is only 4.6%-5.2% (much lower than that of the present invention which is greater than 11%). This shows that too much or too little content of rare earth elements will reduce the strength and toughness of the brazed joint after brazing. Thus, it is proved that by adding rare earth elements and controlling the content of rare earth elements to be 0.1%-0.3%, the present invention can improve the strength (the tensile strength of the brazed joint is 930-950 MPa) and toughness of the brazed joint, while reducing the brittleness of the brazed joint (the elongation after fracture is 11%-15%, much higher than the elongation after fracture of the prior art which is <5%), broadening the application range of titanium and its alloys, and enabling them to be applied to occasions with higher requirements for joint performance.

[0147] In addition, by comparing the data in Table 3 and Table 7, it can also be seen that when the melting temperature is too low (not within the range of 1200 - 1400 °C), the tensile strength of the brazed joint is only 870 MPa (far lower than that of the present invention which is greater than 930 MPa), and the elongation after fracture of the fracture surface is only 6.1% (far lower than that of the present invention which is greater than 11%). This proves that the melting temperature also has a great influence on the strength and toughness of the brazed joint. Controlling the melting temperature to 1200 - 1400 °C can improve the strength (the tensile strength of the brazed joint is 930 - 950 MPa) and toughness of the brazed joint, while reducing the brittleness of the brazed joint (the elongation after fracture is 11% - 15%, much higher than the elongation after fracture <5% of the prior art), broadening the scope of use of titanium and its alloys, enabling it to be applied to occasions with higher requirements for joint performance.

[0148] In addition, as can be seen from Table 4, using the titanium-based filler metal, preparation method and brazing method of the present invention, the typical structure of the obtained brazed joint is a lamellar structure, and the proportion of the lamellar structure is as high as 75% - 90%, thus making the strength and toughness of the brazed joint excellent.

[0149] Example 7 (Spindle-shaped cooling roll, core barrel following)

[0150] In this example, a rotating cooling roll with a shaft diameter of 100 mm, a cooling sleeve made of copper, an outer diameter of 380 mm, a core barrel outer diameter of 304 mm, and four parallel spiral grooves opened on the inner wall of the copper sleeve is used. The width-to-height ratio D / h of the spiral groove is 2.5, and the pitch S is 80 mm.

[0151] Example 8 (Spindle-shaped cooling roll, core barrel rotating)

[0152] This example is basically the same as Example 7, the difference being that it further includes a locking member (snap fastener) for fixing the core barrel 4 to the rotating shaft 1 to enable the core barrel to be in a rotating state.

[0153] Comparative Example 4 (Right-angled cooling roll, core barrel rotating)

[0154] Compared with Example 7, the structure of the rotating cooling roll is the structure involved in the patent with the patent number ZL201621099453.5.

[0155] Under the same simulation conditions, the velocity field and temperature field during the cooling of the rotating cooling rolls of Example 7, Example 8 and Comparative Example 4 were respectively analyzed by means of finite element simulation, and the results are as Figure 14-1 、 Figure 14-2 、 Figure 15-1 and Figure 15-2 shown, and the simulation data are listed in Table 8.

[0156] Table 8 Simulation data analysis table

[0157]

[0158]

[0159] It can be seen from the data in Table 8 that the water outlet speed of the spindle-shaped cooling roller (Example 7 and Example 8) of the present invention is significantly greater than the water outlet speed of the right-angle cooling roller (Comparative Example 4). After the cooling medium passes through the spindle-shaped copper roller, the outlet speed is faster, indicating that the cooling medium can take away more heat in a short time, so that the water outlet temperature of the spindle-shaped cooling roller (Example 7 and Example 8) is significantly higher than the water outlet temperature of the right-angle cooling roller (Comparative Example 4), proving that the cooling intensity of the spindle-shaped cooling roller is significantly greater than the cooling intensity of the right-angle cooling roller.

[0160] Furthermore, by comparing the data of Example 7 and Example 8 in Table 8, it is found that compared with the core barrel rotation (Example 8), the core barrel follower (Example 7) has a faster water outlet speed, and the cooling medium between the cooling jacket and the core barrel has a smaller speed along the tangential direction. The smaller the speed of the cooling medium between the cooling jacket and the core barrel along the tangential direction, the smaller the effect of the centrifugal force. It can be seen that compared with the core barrel rotation (Example 8), the core barrel follower (Example 7) can further reduce the influence of the centrifugal force, improve the axial passing capacity of the cooling medium, further improve the cooling efficiency, and then improve the cooling intensity.

[0161] In addition, by Figure 14-1 It can be seen that when the core barrel rotates, the cooling water flow rate is faster (the cloud is red), but Figure 15-1 It can be further known that the fast speed is because its tangential speed is large, that is, it is greatly affected by the centrifugal force, which ultimately causes the outlet speed to be slow.

[0162] Example 9

[0163] This embodiment is basically the same as Embodiment 1, except that the rotating cooling roller in the vacuum quenching equipment is the cooling roller of Embodiment 8.

[0164] Comparative Example 5

[0165] This comparative example is substantially the same as Example 1, except that the rotating cooling roller in the vacuum quenching apparatus is the cooling roller of Comparative Example 4.

[0166] The yield rates of titanium-based solders (amorphous strips) of Examples 1-6, Example 9 and Comparative Example 5 are shown in Table 9.

[0167] Table 9 Yield of amorphous strip

[0168] Number Yield rate / % Example 1 85 Example 2 87 Example 3 88 Example 4 87 Example 5 90 Example 6 86 Example 9 81 Comparative example 5 48

[0169] As can be seen from Table 9, in the vacuum rapid quenching process, for the vacuum rapid quenching equipment composed of a spindle-shaped rotating cooling roll, the yield rate of the amorphous strip is above 80% (specifically 81%-90%), while for the vacuum rapid quenching equipment composed of a right-angled rotating cooling roll, the yield rate of the amorphous strip is 48%. It can be seen therefrom that in the preparation method of the solder of the present invention, by using a vacuum rapid quenching equipment with strong cooling intensity and uniform cooling, the yield rate of preparing the titanium-based alloy into a titanium-based solder (amorphous strip) is increased from about 50% to above 80%.

[0170] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A titanium-based alloy, characterized in that: In terms of mass percentage, it includes: Zr, 5%-30%, Cu, 10%-15%, Ni, 10%-15%, Nb, 0.5%-3.5%, rare earth elements, 0.1%-0.3%; the balance is Ti and unavoidable trace impurities; The rare earth element includes one or more of La, Ce and Y.

2. The titanium-based alloy according to claim 1, characterized in that Calculated by mass percentage, the titanium-based alloy includes: Zr, 15%-25%, Cu, 12%-15%, Ni, 12%-15%, Nb, 2%-3%, rare earth elements, 0.1%-0.3%; the remainder is Ti and inevitable trace impurities.

3. A titanium-based brazing filler metal, characterized in that: The titanium-based alloy comprises the titanium-based alloy as claimed in claim 1 or 2.

4. The titanium-based brazing filler metal according to claim 3, characterized in that: The melting point of the titanium-based solder is 820-878°C.

5. The titanium-based brazing filler metal according to claim 3, characterized in that: The titanium-based solder has a thickness of 0.02-0.04 mm and a width of 40-100 mm.

6. A method for preparing the titanium-based brazing filler metal according to any one of claims 3 to 5, characterized in that: The steps include: Step 1: Melting the titanium-based alloy according to claim 1 or 2 into an alloy ingot; Step 2: Prepare the alloy ingot into titanium-based brazing filler metal through vacuum rapid quenching process.

7. The preparation method according to claim 6, characterized in that: In step 1, the smelting temperature is 1200-1400°C.

8. The preparation method according to claim 6, characterized in that: In step 2, a vacuum quenching process is performed in a vacuum quenching device.

9. The preparation method according to claim 8, characterized in that: The vacuum rapid quenching equipment comprises a melting furnace vacuum chamber, a rapid quenching vacuum chamber, and a vacuum silo which are arranged in sequence; a rotating cooling roller is arranged in the rapid quenching vacuum chamber.

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