Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal, preparation method and application thereof

Abstract

The application discloses a Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal and a preparation method and a brazing method thereof, relates to a high-entropy brazing filler metal for welding TiAl alloy and Ni-based high-temperature alloy, and belongs to the technical field of welding materials. The brazing filler metal is composed of 20% of Ti, 20% of Zr, 20% of Cu, 20% of Ni and 20% of Mn in terms of atomic percentage. The steps are as follows: ingredients are prepared according to the above component content, raw materials are smelted by an electric arc smelting method to obtain a brazing filler metal master alloy ingot. After the alloy ingot is crushed into small pieces, a single-roller tape casting method is used to prepare the Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal. The high-entropy brazing filler metal has a liquidus temperature of 1130 DEG C, has the advantages of low cost, simple assembly, good wettability with a base material, and easy formation of a brazing joint with TiAl alloy and Ni-based high-temperature alloy, and the brazing joint has excellent performance.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal, its preparation method, and its application. Background Technology

[0002] TiAl alloys, possessing both lightweight and heat-resistant properties, are widely considered ideal materials for manufacturing critical hot-section components in aerospace and other applications. However, machining integral components using only TiAl alloys is extremely difficult and significantly more expensive. Joining TiAl alloys with Ni-based superalloys offers complementary advantages in cost reduction and performance enhancement. Due to the significant compositional differences between the two materials, obtaining a high-quality weld joint is crucial for the effective joining of TiAl alloys and Ni-based superalloys.

[0003] Brazing has the advantages of minimal impact on the microstructure and properties of the base materials, and low stress and deformation, making it suitable for joining TiAl alloys and Ni-based superalloys. When brazing, the microstructure and properties of the brazed joint are directly affected by the brazing filler metal. The main elements of the two base materials, Ti, Al, and Ni, readily react to form hard and brittle Ti-Ni and Ti-Al-Ni intermetallic compounds, initiating cracks and thus deteriorating the mechanical properties of the joint. Summary of the Invention

[0004] To address the problem of brittle intermetallic compounds easily forming during the brazing of TiAl alloys and Ni-based superalloys in existing technologies, this invention provides a Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal, its preparation method, and its applications. Utilizing the design theory of high-entropy alloys, the high-entropy effect is introduced to optimize the composition of the brazing filler metal, thereby improving the joint microstructure and suppressing the precipitation of brittle phases. The technical solution of this invention is as follows:

[0005] The present invention provides a Ti-Zr-Cu-Ni-Mn high-entropy solder, the chemical composition of which comprises the following components by atomic percentage: Ti: 15%~25%, Zr: 15%~25%, Cu: 15%~25%, Ni: 15%~25%, Mn: 15%~25%.

[0006] The preparation method of the above-mentioned Ti-Zr-Cu-Ni-Mn high-entropy solder is carried out according to the following steps:

[0007] Step 1: After converting the atomic percentage of the high-entropy solder into a mass percentage, weigh the raw materials. All raw materials using elements must be pure metals with a purity of 99.9% or higher.

[0008] Step Two: In a vacuum arc furnace, the raw materials prepared in Step One are placed into a copper crucible for melting, and remelted repeatedly 4-5 times to obtain a high-entropy brazing filler alloy ingot, wherein:

[0009] Element Ti was placed in the bottom layer of the crucible;

[0010] Element Cu should be kept out of direct contact with the crucible;

[0011] All elements except Ti were placed into the crucible in order of increasing melting point;

[0012] Step 3: The high-entropy brazing filler metal master alloy ingot from Step 2 is crushed into fragments. The fragments of the high-entropy brazing filler metal master alloy ingot are heated and melted in a rapid solidification equipment, and then Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal is prepared by single-roller spinning method. The brazing filler metal is in the form of fragments.

[0013] Furthermore, in the above-mentioned method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder, the oxides and oil stains on the surface of the raw materials must be removed before weighing the raw materials in step one.

[0014] Furthermore, in the preparation method of the above-mentioned Ti-Zr-Cu-Ni-Mn high-entropy solder, in step two of the melting process, the vacuum degree of the vacuum arc furnace is evacuated to 3.5 × 10⁻⁶. -3 After the pressure drops below Pa, argon gas is introduced, and the process is carried out under the protection of an argon atmosphere.

[0015] Furthermore, in the above-mentioned method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder, the method used in step three, crushing the master alloy ingot into fragments, is mechanical crushing.

[0016] Furthermore, in the above-mentioned method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder, the rapid solidification equipment in step three is a vacuum melting and spinning machine. Heating and melting refers to placing the fragments of the master alloy ingot into a quartz tube, and then placing it into the vacuum melting and spinning machine to melt it through induction melting.

[0017] Furthermore, in the above-mentioned method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder, when step three is carried out using the single-roller spinning method, the specific process parameters are as follows: the rotation frequency of the rotating copper roller is 30-40 Hz, the distance between the melt outlet and the surface of the copper roller is 0.4-0.5 mm, the amount of argon protective gas is 300-400 mbar, and the argon pressure used for melt injection is 100-200 mbar.

[0018] This invention also discloses a method for brazing TiAl alloys and Ni-based superalloys using the above-mentioned Ti-Zr-Cu-Ni-Mn high-entropy solder, which is carried out according to the following steps:

[0019] Remove surface impurities and oxides by sanding the base material surfaces to be welded with sandpaper of the same grit. Place the Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal between the base material surfaces to be welded and then place it in a vacuum brazing furnace. Heat the furnace to 1170 ℃ in a vacuum environment, hold for 30 min, cool to 200 ℃, and then remove the workpiece to complete the brazing.

[0020] Further, in the above method of brazing TiAl alloys and Ni-based superalloys using Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal, the sandpaper of the same mesh size is specifically 80 mesh, the liquidus temperature of the Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal is 1130℃, and the contact area of ​​the brazed joint base material is 70 mm². 2 The added brazing filler metal weighs 60 mg, ensuring that it fully fills the gap between the brazing seams.

[0021] Furthermore, in the above-described method of brazing TiAl alloys and Ni-based superalloys using Ti-Zr-Cu-Ni-Mn high-entropy solder, the vacuum environment of the vacuum brazing furnace refers to a vacuum level below 5 × 10⁻⁶. -4 Pa, where the heating and cooling rates are both 10 °C / min.

[0022] Ti and Ni are the main constituent elements of TiAl alloy and Ni-based superalloy, respectively, which can enable the solder to maintain good wettability and fluidity on the surfaces of the two base materials at the same time. At the same time, Ti and Ni can undergo a eutectic reaction to form a low-melting-point eutectic, which reduces the melting point of the solder.

[0023] Zr and Cu are infinitely miscible with Ti and Ni elements, respectively, and have low melting points, which is beneficial for further reducing the melting point of the alloy system; among them, due to the large size difference between Zr and Ti, Zr can be used as a solid solution to enhance the properties of Ti alloys.

[0024] Mn has a low melting point and is inexpensive. It is a eutectoid β-stabilizing element that can improve the strength and plasticity of Ti alloys.

[0025] The advantages and beneficial effects of this invention are as follows:

[0026] (1) Control of solder melting temperature: During brazing, the solder must melt while the base metal remains unmelted. Therefore, ensuring the solder melting temperature is within a suitable range during composition design is crucial. The Ti-Zr-Cu-Ni-Mn high-entropy solder of this invention has relatively low melting points for Ni, Mn, and Cu (1455 ℃, 1246 ℃, and 1084.62 ℃ respectively), which is beneficial for controlling the solder melting point. Simultaneously, Ti and Zr can undergo a eutectic reaction with Cu and Ni to lower the solder melting point, resulting in a suitable melting temperature. The liquidus temperature of the Ti-Zr-Cu-Ni-Mn high-entropy solder provided by this invention is 1130 ℃ lower than that of the base metal.

[0027] (2) Wettability of the solder and the base material: During the brazing process, the solder melts into a liquid state, which then wets, fills, and interacts with the base material. After cooling and solidification, it forms a strong joint, thus achieving the connection of the base materials. Therefore, good wettability of the liquid solder on the base material surface is a basic condition for the solder to fill the gap and form a brazed joint. The Ti-Zr-Cu-Ni-Mn high-entropy solder of this invention, wherein Zr and Cu can be infinitely dissolved with the main elements Ti and Ni in the base material, respectively, can significantly reduce the interfacial tension, thereby significantly improving the wettability of the solder. The Ti-Zr-Cu-Ni-Mn high-entropy solder provided by this invention exhibits good wettability on both base materials; at the same time, the metal components of the base material contained in the solder can reduce the dissolution of the base material into the solder, preventing excessive dissolution of the base material from deteriorating the fluidity of the liquid solder and causing it to fail to fill the joint gap.

[0028] (3) Interaction between brazing filler metal and base metal: During brazing, a series of metallurgical processes, such as dissolution, diffusion, solidification, and crystallization, occur between the base metal and the brazing filler metal, resulting in a non-uniform microstructure of the brazed joint and extremely complex joint performance. Brittle intermetallic compounds are easily generated during the brazing of TiAl alloys and Ni-based superalloys, leading to deterioration of the brazed joint performance. Therefore, suppressing the formation of intermetallic compounds at the joint is key to improving joint strength. The Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal described in this invention, due to the unique properties of high-entropy alloys, exhibits a high-entropy effect in thermodynamics that suppresses the formation of ordered intermetallic compounds during solidification, making it easier to form multi-principal solid solutions that are more stable. The room temperature shear strength of dissimilar brazed joints of TiAl alloys and Ni-based superalloys made with the Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal provided in this invention reaches 214 MPa.

[0029] (4) The brazing filler metal of the present invention has a uniform composition and is in the form of shavings, which facilitates assembly and makes it easier to control the weld width. Compared with other brazing filler metals used for brazing TiAl alloys and Ni-based high-temperature alloys, the raw material cost of the brazing filler metal of this patent is significantly reduced, effectively controlling the production cost. At the same time, the liquidus temperature of the high-entropy alloy brazing filler metal proposed in the present invention is 1130 ℃, which ensures good heat resistance of the joint and can meet the working requirements of the joint at high temperature.

[0030] (5) The brazing method described in this invention is carried out in a vacuum, which can avoid the adverse effects of air on the joint performance. At the same time, compared with other welding methods, no pressure needs to be applied, and the process is simpler. Attached Figure Description

[0031] Figure 1 The scanning electron microscope (SEM) microstructure of the Ti-Zr-Cu-Ni-Mn high-entropy solder master alloy ingot prepared in Example 1;

[0032] Figure 2 The scanning electron microscope (SEM) microstructure of the joint cross section of the TiAl alloy and Ni-based superalloy K416B brazed with Ti-Zr-Cu-Ni-Mn high-entropy solder in Example 1 is shown.

[0033] Figure 3 The image shows the scanning electron microscope (SEM) microstructure of the cross-section of the joint between TiAl alloy and Ni-based superalloy K416B brazed with Ti-Zr-Cu-Ni solder in Comparative Example 1. Detailed Implementation

[0034] The preparation method and application of this Ti-Zr-Cu-Ni-Mn high-entropy solder are described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] This embodiment provides a Ti-Zr-Cu-Ni-Mn high-entropy solder, whose chemical composition, by atomic percentage, includes: Ti: 20%, Zr: 20%, Cu: 20%, Ni: 20%, Mn: 20%. Its preparation method includes the following steps: preparing 30 g of metal raw materials, specifically: weighing 4.54 g of elemental Ti (purity above 99.9%), 8.65 g of elemental Zr, 6.03 g of elemental Cu, 5.57 g of elemental Ni, and 5.21 g of elemental Mn, all with a purity of 99.9% or higher and free from oxides and impurities.

[0037] The elemental metals are placed into the copper crucible of the vacuum arc furnace in order of increasing melting point, with care taken to avoid contact between the Cu element and the crucible. The vacuum level in the furnace chamber is then evacuated to 3.5 × 10⁻⁶. -3After the pressure drops below Pa, argon gas is introduced, and the melting process is carried out under the protection of the argon atmosphere. This process is repeated four times to obtain a high-entropy brazing filler alloy ingot.

[0038] The obtained high-entropy brazing master alloy ingot was mechanically crushed into small pieces. Appropriately sized pieces were selected, ultrasonically cleaned in anhydrous ethanol for 10 minutes, and then dried. The cleaned pieces were placed into a pointed quartz tube, which was then placed into the induction coil of a vacuum melting and spinning machine. The position of the quartz tube was adjusted to ensure that the distance between the quartz tube outlet and the surface of the copper roller was 0.4 mm during injection. The vacuum level in the furnace chamber was then evacuated to 3.5 × 10⁻⁶ mm. -3 After the pressure drops below Pa, 300 mbar of argon gas is simultaneously introduced into the furnace chamber and the gas storage tank. Once the pressure gauge reading stabilizes, argon gas is then introduced into the gas storage tank. The argon gas pressure used for melt injection is 150 mbar. The rotation frequency of the copper roller is set to 38 Hz. The main switch of the induction power supply is turned on, and the power of the induction power supply is adjusted to melt the fragments of the brazing filler alloy ingot. When the fragments in the tube emit a dazzling white light and are completely and uniformly melted, and the melt fluctuates, injection can begin. The melt is injected onto the surface of the high-speed rotating copper roller and rapidly cooled to obtain fragmented high-entropy brazing filler metal.

[0039] like Figure 1 The image shows the scanning electron microscope (SEM) microstructure of the Ti-Zr-Cu-Ni-Mn high-entropy solder master alloy ingot prepared in Example 1.

[0040] The Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal prepared in this embodiment was used for brazing TiAl alloy and Ni-based superalloy K416B. The specific brazing method is as follows:

[0041] The surfaces of the TiAl alloy and Ni-based superalloy K416B to be soldered were polished with 80# sandpaper to remove surface impurities and oxides, and then ultrasonically cleaned in anhydrous ethanol for 10 min before drying. 60 mg of Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal was placed between the TiAl alloy and Ni-based superalloy K416B surfaces to be soldered, specifically in the following order from top to bottom: TiAl alloy / Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal / Ni-based superalloy K416B. The assembled components were then placed in a vacuum brazing furnace, and the furnace was kept at a vacuum level below 5 × 10⁻⁶. -4 The workpiece was heated to 1170 °C at a rate of 10 °C / min under an ambient temperature of Pa, held for 30 min, and then cooled to 200 °C at a rate of 10 °C / min before being removed to complete the brazing. The shear strength of the brazed joint at room temperature was 214 MPa.

[0042] like Figure 2The image shows the scanning electron microscope (SEM) microstructure of the cross-section of the joint between TiAl alloy and Ni-based superalloy K416B brazed with Ti-Zr-Cu-Ni-Mn high-entropy solder in Example 1.

[0043] Comparative Example 1

[0044] This comparative example provides a commercial Ti-Zr-Cu-Ni solder, whose chemical composition, by mass percentage, includes: Ti: 37.5%, Zr: 37.5%, Cu: 15%, Ni: 10%. Its preparation method includes the following steps: preparing 30 g of metal material, specifically: weighing 11.25 g of elemental Ti (purity above 99.9%), 11.25 g of elemental Zr, 4.50 g of elemental Cu, and 3.00 g of elemental Ni, all with a purity of 99.9% or higher and free from oxides and impurities.

[0045] The elemental metals are placed into the copper crucible of the vacuum arc furnace in order of increasing melting point, with care taken to avoid contact between the Cu element and the crucible. The vacuum level in the furnace chamber is then evacuated to 3.5 × 10⁻⁶. -3 After the pressure drops below Pa, argon gas is introduced, and the melting process is carried out under the protection of the argon atmosphere. This process is repeated four times to obtain a high-entropy brazing filler alloy ingot.

[0046] The obtained high-entropy brazing master alloy ingot was mechanically crushed into small pieces. Appropriately sized pieces were selected, ultrasonically cleaned in anhydrous ethanol for 10 minutes, and then dried. The cleaned pieces were placed into a pointed quartz tube, which was then placed into the induction coil of a vacuum melting and spinning machine. The position of the quartz tube was adjusted to ensure that the distance between the quartz tube outlet and the surface of the copper roller was 0.4 mm during injection. The vacuum level in the furnace chamber was then evacuated to 3.5 × 10⁻⁶ mm. -3 After the pressure drops below Pa, 300 mbar of argon gas is simultaneously introduced into the furnace chamber and the gas storage tank. Once the pressure gauge reading stabilizes, argon gas is then introduced into the gas storage tank. The argon gas pressure used for melt injection is 150 mbar. The rotation frequency of the copper roller is set to 38 Hz. The main switch of the induction power supply is turned on, and the power of the induction power supply is adjusted to melt the broken pieces of the brazing filler alloy ingot. When the broken pieces in the tube emit a dazzling white light and are completely and uniformly melted, and the melt fluctuates, injection can begin. The melt is injected onto the surface of the high-speed rotating copper roller and rapidly cooled to obtain a foil-shaped high-entropy brazing filler metal.

[0047] The Ti-Zr-Cu-Ni brazing filler metal prepared in this comparative example was used for brazing TiAl alloy and Ni-based superalloy K416B. The specific brazing method is as follows:

[0048] The surfaces of the TiAl alloy and Ni-based superalloy K416B to be soldered were polished with 80-grit sandpaper to remove surface impurities and oxides, and then ultrasonically cleaned in anhydrous ethanol for 10 min before drying. 60 mg of brazing filler metal was cut into small pieces and placed between the TiAl alloy and Ni-based superalloy K416B surfaces to be soldered, specifically in the following order from top to bottom: TiAl alloy / Ti-Zr-Cu-Ni brazing filler metal / Ni-based superalloy K416B. The assembled parts were then placed in a vacuum brazing furnace, and the furnace was kept at a vacuum level below 5 × 10⁻⁶. -4 The workpiece was heated to 940 °C at a rate of 10 °C / min under an ambient temperature of Pa, held at that temperature for 30 min, and then cooled to 200 °C at a rate of 10 °C / min before being removed to complete the brazing. The shear strength of the brazed joint at room temperature was 132 MPa.

[0049] like Figure 3 The image shows the scanning electron microscope (SEM) microstructure of the cross-section of the joint between TiAl alloy and Ni-based superalloy K416B brazed with Ti-Zr-Cu-Ni solder in Comparative Example 1.

[0050] In summary, through comparison, it can be concluded that the Ti-Zr-Cu-Ni-Mn high-entropy brazing filler metal provided by this invention can achieve higher joint shear strength than existing brazing filler metals when brazing TiAl alloys and Ni-based superalloys.

[0051] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a Ti-Zr-Cu-Ni-Mn high-entropy solder, characterized in that, The chemical composition of the high-entropy solder, by atomic percentage, is as follows: Ti: 15%–25%, Zr: 15%–25%, Cu: 15%–25%, Ni: 15%–25%, Mn: 15%–25%; The method for preparing the high-entropy solder includes the following steps: Step 1: After converting the atomic percentage of the high-entropy solder into a mass percentage, weigh the raw materials. All raw materials using elements must be pure metals with a purity of 99.9% or higher. Step Two: In a vacuum arc furnace, the raw materials prepared in Step One are placed into a copper crucible for melting, and remelted repeatedly 4-5 times to obtain a high-entropy brazing filler alloy ingot, wherein: Element Ti was placed in the bottom layer of the crucible; Element Cu should be kept out of direct contact with the crucible; All elements except Ti were placed into the crucible in order of increasing melting point; Step 3: Crush the high-entropy brazing filler alloy ingot from Step 2 into fragments. After the fragments of the high-entropy brazing filler alloy ingot are heated and melted in a rapid solidification equipment, they are used to prepare Ti-Zr-Cu-Ni-Mn shaving high-entropy brazing filler alloy by single-roller spinning method. In step three, when the single-roller spinning method is used for preparation, the specific process parameters are as follows: the rotation frequency of the rotating copper roller is 30-40 Hz, the distance between the melt outlet and the surface of the copper roller is 0.4-0.5 mm, and the argon gas pressure used for melt injection is 100-200 mbar.

2. The method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder according to claim 1, characterized in that, In step two, during the melting process, the vacuum level in the vacuum arc furnace is evacuated to 3.5 × 10⁻⁶. -3 After the pressure drops below Pa, argon gas is introduced, and the process is carried out under the protection of an argon atmosphere.

3. The method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder according to claim 1, characterized in that, Step three involves mechanically crushing the master alloy ingot into smaller pieces.

4. The method for preparing Ti-Zr-Cu-Ni-Mn high-entropy solder according to claim 1, characterized in that, The rapid solidification equipment mentioned in step three is a vacuum melting and spinning machine. Heating and melting refers to placing the fragments of the master alloy ingot into a quartz tube, and then placing it into the vacuum melting and spinning machine to melt it through induction melting.

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