Ta-containing high plasticity nickel-based superalloy and method of making same

Abstract

The application belongs to the technical field of alloy materials, and discloses a Ta-containing high-plasticity nickel-based high-temperature alloy and a preparation method thereof. The application aims to design a nickel-based alloy with plasticity exceeding 60% at room temperature and stable mechanical strength. The alloy composition is as follows: Cr: 20.5-23.0 wt%, Co: 0.5-2.5 wt%, Mo: 7.0-10.0 wt%, W: 0.2-1.0 wt%, Fe: 17.0-20.0 wt%, Mn: 0-1 wt%, C: 0.05-0.15 wt%, Ta: 0.5-5.0 wt%, B: 0.03 wt%, and the balance is Ni. The target components are allocated, and then the alloy ingot is obtained through grinding, cleaning, smelting and casting. The alloy ingot is hot-rolled to 2.4 mm at 1160 DEG C, and then annealed at 1160 DEG C for 1 h. After that, the alloy ingot is cold-rolled to 1.2 mm. The heat treatment adopts solid solution at 1150 DEG C for 10 min and water cooling. Through the fusion of another solid solution element and the fusion of another grain boundary strengthening element, the plasticity of the alloy is modified by adjusting the heat treatment process. The obtained alloy has a room temperature elongation greater than 55% and a strength greater than 670 MPa, and is suitable for high-temperature alloy plates, strips and foils.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy design, and in particular to a high-ductility nickel-based high-temperature alloy and its composition optimization design method. Background Technology

[0002] Nickel-based superalloys are core materials for high-end high-temperature structures, possessing excellent high-temperature strength, creep resistance, oxidation resistance, and corrosion resistance. They can operate stably for extended periods under harsh conditions of high temperature, high pressure, alternating loads, and complex corrosive media, exhibiting significantly superior overall performance compared to ordinary alloys. Due to their outstanding high-temperature comprehensive performance, these alloys are widely used in the hot-end core components of high-end equipment such as heavy-duty ground gas turbines and aerospace propulsion systems, serving as a key foundational material supporting the efficient and long-life operation of high-end power equipment. In engineering applications, excellent ductility and large plastic deformation capacity are the most core and critical performance indicators of nickel-based superalloys, directly determining their formability and engineering application range. GH3536 alloy is an excellent nickel-based wrought superalloy with outstanding processing performance, capable of both hot forming such as forging and cold working processes such as cold rolling. Even at 1200℃, it maintains good ductility, exhibiting a wide plasticity adaptation temperature range and strong process compatibility. Ultra-thin sealing foil is a core component for precision thin-walled applications, with a finished thickness of only 0.05 mm. This places extremely high demands on the plastic deformation capacity, forming uniformity, and process adaptability of the raw materials. GH3536 alloy possesses excellent high and low temperature ductility and good plastic forming ability, which can meet the extreme processing requirements of ultra-thin thin-walled components, making it an ideal candidate material for the preparation of ultra-thin sealing foil. In the precision forming process of foil cold rolling and plastic thinning, if the alloy's plasticity is insufficient, it is prone to processing defects such as cracks, peeling, and edge cracks during cold deformation, seriously affecting the finished product qualification rate and component dimensional accuracy. However, there is a typical strong-plasticity trade-off relationship in material properties. Simply improving the forming plasticity of the material often sacrifices the room temperature and high temperature mechanical strength of the alloy to a certain extent, leading to a decrease in the load-bearing capacity and high-temperature service stability of the component, posing a significant threat to the service safety and service life under long-term combustion, high-load, and high-temperature conditions. Therefore, achieving a synergistic improvement in alloy strength and plasticity through precise composition control and microstructure optimization, and breaking through the performance trade-off bottleneck of traditional materials, remains a key technical problem that urgently needs to be solved at this stage. The composition range of GH3536 alloy is: Cr: 20.5–23.0 wt%, Co: 0.5–2.5 wt%, Mo: 7.0–10.0 wt%, W: 0.2–1.0 wt%, Fe: 17.0–20.0 wt%, Mn: 0–1 wt%, C: 0.05–0.15 wt%, B: 0.03 wt%, with the balance being Ni. If only fine-tuning and optimization are carried out within the existing fixed standard composition range of GH3536, the inherent composition system and microstructure characteristics limit the achievement of significant breakthroughs in the material's overall performance, making it impossible to further improve its high-plasticity forming capability while ensuring stable high-temperature strength. In summary, developing a modified alloy system that balances ultra-high foil forming plasticity with stable mechanical strength is a significant technical challenge currently facing the field of aerospace sealing materials. Summary of the Invention

[0003] In view of this, the present invention proposes a high-plasticity nickel-based superalloy containing Ta and its preparation method, the main purpose of which is to produce a material that can significantly improve the plasticity of nickel-based alloys while also having good strength.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-ductility nickel-based superalloy containing Ta, comprising the following components by mass percentage: Cr: 20.5-23.0 wt%, Co: 0.5-2.5 wt%, Mo: 7.0-10.0 wt%, W: 0.2-1.0 wt%, Fe: 17.0-20.0 wt%, Mn: 0-1 wt%, C: 0.05-0.15 wt%, Ta: 0.5-5.0 wt%, B: 0.03 wt%, with the balance being Ni.

[0005] As a further improvement of a Ta-containing high-ductility nickel-based superalloy, the preferred composition includes the following components by mass percentage: Cr: 20.8 wt%; Co: 2.5 wt%; Mo: 8.3 wt%; W: 0.9 wt%; C: 0.07 wt%; Fe: 18.6 wt%; Mn: 0.55 wt%; Ta: 0.5 wt%; B: 0.03 wt%; with the balance being Ni.

[0006] Preferably, the composition comprises the following components by mass percentage: Cr: 20.8 wt%; Co: 2.5 wt%; Mo: 8.3 wt%; W: 0.9 wt%; C: 0.07 wt%; Fe: 18.6 wt%; Mn: 0.55 wt%; Ta: 2.5 wt%; B: 0.03 wt%; with the balance being Ni.

[0007] Preferably, the composition comprises the following components by mass percentage: Cr: 20.8 wt%; Co: 2.5 wt%; Mo: 8.3 wt%; W: 0.9 wt%; C: 0.07 wt%; Fe: 18.6 wt%; Mn: 0.55 wt%; Ta: 5 wt%; B: 0.03 wt%; with the balance being Ni.

[0008] As described in Example 3, it is evident that adding 5% Ta to the GH3536 alloy improves both the room temperature tensile strength and the 750°C tensile strength of the new alloy compared to the original GH3536 alloy. However, its room temperature and high temperature elongation are significantly higher than those of the existing GH3536 alloy. Compared to Example 1, even with only 0.5% Ta added to the GH3536 alloy, the new alloy exhibits far superior plasticity. In other words, the primary purpose of adding Ta is to enhance the alloy's plasticity.

[0009] Another object of the present invention is to provide a method for preparing the Ta-containing high-ductility nickel-based superalloy, comprising the following steps: S1. Remove the oxide scale from the surface of metal particles such as Ni, Mo, Co, Fe, and Cr, and then perform ultrasonic vibration cleaning in anhydrous ethanol: S2. Place the cleaned metal raw material into a consumable vacuum arc furnace, a non-consumable vacuum arc furnace, or a vacuum suspension melting furnace, and evacuate the vacuum to 3×10⁻⁶. -3 Stop when the pressure drops below Pa and fill with high-purity argon as a protective atmosphere; S3. Under vacuum or argon atmosphere conditions, the high temperature generated by electric arc discharge melts the consumable electrode or the metal raw material is melted into an alloy by heating with induced current. The melting is repeated 3 to 4 times to ensure that the alloy composition is uniform. After the master alloy is melted uniformly, it is injected into the mold to obtain an ingot with a regular shape.

[0010] S4. The prepared alloy composition was heat-treated, followed by tensile tests at room temperature and 750℃, and finally a nickel-based high-temperature alloy with high plasticity and high structural stability was prepared.

[0011] Further improvements to the preparation method of Ta-containing high-ductility nickel-based superalloys: Preferably, in the tensile test described in step S3, the room temperature tensile rate is 1×10⁻⁶. -3 The tensile speed at 750℃ is 1.8 mm / min.

[0012] Preferably, the rolling process in step S3 is to hot roll a 16mm ingot to 2.4mm at 1160℃, anneal it at 1160℃ for 1 hour, and then cold roll it to 1.2mm.

[0013] Preferably, in step S3, the heat treatment involves solution treatment at 1150 °C for 10 minutes, followed by water cooling.

[0014] Mechanism of the invention:

[0015] This invention significantly improves the plasticity of a GH3536 alloy matrix by doping it with Ta and Bo, without sacrificing its strength, achieving a synergistic optimization of strength and plasticity. From the perspective of alloy modification mechanism, the atomic radius of Ta is significantly larger than that of Ni atoms in the matrix. Introducing Ta into the GH3536 alloy system effectively reduces the stacking fault energy, achieving both solid solution strengthening and plasticity enhancement. On one hand, Ta atoms exist in solid solution form in the alloy matrix, achieving solid solution strengthening through lattice distortion, ensuring that the overall strength of the alloy does not decrease. On the other hand, the reduction of stacking fault energy effectively regulates the dislocation movement and slip mechanism of the alloy, improving its deformation capacity and significantly enhancing its plasticity. Simultaneously, this invention precisely matches and optimizes key preparation parameters such as hot and cold rolling processes, heat treatment temperature, holding time, and cooling methods, precisely controlling the alloy grain size to maintain it stably within a suitable range, providing microstructural assurance for the alloy to maintain excellent plasticity. Furthermore, by setting a gradient of Ta element doping concentration, this invention systematically explores the influence of Ta element content on the microstructure and mechanical properties of GH3536 alloy, screens out the optimal element ratio and process parameter combination, and finally obtains a modified GH3536 alloy material with excellent strength and plasticity matching.

[0016] Furthermore, the purpose of this invention is to provide an application of the above-mentioned Ta-containing high-plasticity nickel-based superalloy in plates, strips, and foils.

[0017] The advantages of this invention compared to the prior art are as follows: 1) This invention provides a high-ductility nickel-based superalloy containing Ta, comprising Ni, Co, Cr, Mo, W, Fe, Mn, C, B, and Ta. The main functions of these 10 elements are described below: Ni is the primary element for forming a face-centered cubic γ matrix. Co, as an important solid solution strengthening element, has good thermal conductivity; Cr mainly plays a role in solid solution strengthening and oxidation resistance; Mo and W, as solid solution strengthening elements, can improve high-temperature strength; Fe is also a solid solution strengthening element, and its low price can significantly reduce costs; C forms carbides, which strengthen grain boundaries at high temperatures; the introduction of B can optimize the morphology and size of carbides; B and C together strengthen grain boundaries, thereby improving tensile ductility. The important innovation of this invention is the addition of Ta, which, due to its larger atomic radius than the Ni matrix, can reduce stacking fault energy and simultaneously play a role in solid solution strengthening and improving ductility.

[0018] 2) The technical solution proposed in this invention provides a new development path and alloy system for the research and development of high-performance high-temperature alloys for sealing components. The novel nickel-based high-temperature alloy with both high plasticity and strength obtained by this invention can be used in plates, strips, and foils, and has significant social and economic benefits. Attached Figure Description

[0019] Figure 1 The stress-strain curves for room temperature tensile engineering of Ta-containing high-plasticity nickel-based superalloys are shown.

[0020] The accompanying drawings are merely some embodiments of the present invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort. Detailed Implementation

[0021] It should be understood that the embodiments described in this invention are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0022] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0023] This invention is based on a Ta-containing high-ductility nickel-based superalloy and its preparation method, specifically carried out according to the following steps: (1) Prepare the ingredients according to the target composition, and smelt the metal raw materials after grinding to remove the surface oxide scale and cleaning, and cast them into alloy ingots; (2) The alloy ingot obtained in step (1) is subjected to hot deformation and cold deformation to obtain an alloy with high plasticity and strength.

[0024] In this invention, no special process restrictions are set for pretreatment operations such as ultrasonic cleaning and surface oxide removal of samples. These steps can all be performed using conventional methods in the art and commercially available general-purpose equipment.

[0025] In this invention, the purity of metal raw materials such as Ni, Fe, C, B, Mo, Mn, Ta, W, Cr, and Co should be >99.99%.

[0026] In this invention, the vacuum level in the furnace cavity needs to be pre-evacuated to 3×10 before melting. -3 Next, high-purity argon gas is introduced as a protective atmosphere to strictly control oxidation and impurity contamination of the alloy during the high-temperature melting process. To ensure a high degree of homogeneity in the alloy composition, the melting process requires 3 to 4 repeated remelting cycles.

[0027] In this invention, the initial shape and geometric dimensions of the resulting alloy ingot are not specifically limited. Those skilled in the art can flexibly adjust the shape of the ingot according to actual engineering needs, the specifications of subsequent processing equipment, and the application scenario of the final product.

[0028] Example 1: This embodiment provides a Ta-containing high-ductility nickel-based superalloy and its preparation method. The specific implementation steps are as follows: (1) The alloy composition was selected as follows: Cr: 20.8wt%; Co: 2.5wt%; Mo: 8.3wt%; W: 0.9wt%; C: 0.07wt%; Fe: 18.6wt%; Mn: 0.55wt%; Ta: 0.5wt%; B: 0.03wt%; with the balance being Ni. According to the total proportion, Ni, Cr, Fe, Mo, W, C, Mn, Co, B and Ta particles with a purity of 99.99% were selected, and after grinding to remove the oxide scale, they were ultrasonically cleaned in anhydrous ethanol. The cleaned pure metal particles were placed in the smelting equipment, and the vacuum inside the furnace was drawn to 3×10 -3 Next, high-purity argon gas is introduced and melting begins; the melting process is repeated 3 to 4 times to obtain a uniformly composed ingot.

[0029] (2) The ingot obtained in step (1) is hot rolled at a rolling temperature of 1160℃ to 2.4mm. After rolling, it is annealed at 1160℃ for 1h and then directly cold rolled to 1.2mm to obtain an alloy plate with high plasticity and strength.

[0030] (3) Tensile tests at room temperature and 750℃, with a room temperature tensile rate of 1×10⁻⁶. -3 The tensile speed at 750℃ was 1.8 mm / min, and a high-plasticity nickel-based superalloy containing Ta was finally prepared.

[0031] Example 2: This embodiment provides a Ta-containing high-ductility nickel-based superalloy and its preparation method. The specific implementation steps are as follows: (1) The alloy composition was selected as follows: Cr: 20.8wt%; Co: 2.5wt%; Mo: 8.3wt%; W: 0.9wt%; C: 0.07wt%; Fe: 18.6wt%; Mn: 0.55wt%; Ta: 2.5wt%; B: 0.03wt%; with the balance being Ni. According to the total proportion, Ni, Cr, Fe, Mo, W, C, Mn, Co, B and Ta particles with a purity of 99.99% were selected, and after grinding to remove the oxide scale, they were ultrasonically cleaned in anhydrous ethanol. The cleaned pure metal particles were placed in the smelting equipment, and the vacuum inside the furnace was drawn to 3×10 -3Next, high-purity argon gas is introduced and melting begins; the melting process is repeated 3 to 4 times to obtain a uniformly composed ingot.

[0032] (2) The ingot obtained in step (1) is hot rolled at a rolling temperature of 1160℃ to 2.4mm. After rolling, it is annealed at 1160℃ for 1h and then directly cold rolled to 1.2mm to obtain an alloy plate with high plasticity and strength.

[0033] (3) Tensile tests at room temperature and 750℃, with a room temperature tensile rate of 1×10⁻⁶. -3 The tensile speed at 750℃ was 1.8 mm / min, and a high-plasticity nickel-based superalloy containing Ta was finally prepared.

[0034] Example 3: This embodiment provides a Ta-containing high-ductility nickel-based superalloy and its preparation method. The specific implementation steps are as follows: (1) The alloy composition was selected as follows: Cr: 20.8wt%; Co: 2.5wt%; Mo: 8.3wt%; W: 0.9wt%; C: 0.07wt%; Fe: 18.6wt%; Mn: 0.55wt%; Ta: 5wt%; B: 0.03wt%; with the balance being Ni. According to the total proportion, Ni, Cr, Fe, Mo, W, C, Mn, Co, B and Ta particles with a purity of 99.99% were selected, and after grinding to remove the oxide scale, they were ultrasonically cleaned in anhydrous ethanol. The cleaned pure metal particles were placed in the smelting equipment, and the vacuum inside the furnace was drawn to 3×10 -3 Next, high-purity argon gas is introduced and melting begins; the melting process is repeated 3 to 4 times to obtain a uniformly composed ingot.

[0035] (2) The ingot obtained in step (1) is hot rolled at a rolling temperature of 1160℃ to 2.4mm. After rolling, it is annealed at 1160℃ for 1h and then directly cold rolled to 1.2mm to obtain an alloy plate with high plasticity and strength.

[0036] (3) Tensile tests at room temperature and 750℃, with a room temperature tensile rate of 1×10⁻⁶. -3 The tensile speed at 750℃ was 1.8 mm / min, and a high-plasticity nickel-based superalloy containing Ta was finally prepared.

[0037] The tensile engineering stress-strain curves of the Ta-containing high-ductility nickel-based superalloys in Examples 1-3 are shown below. Figure 1 As shown. From Figure 1 As can be seen, the room temperature elongation of the alloys is greater than 55%, and the elongation of Example 3 reaches 64%.

[0038] The Ta-containing high-ductility nickel-based superalloys selected in Examples 1-3 and the commercially available GH3536 alloy were subjected to mechanical property tests. Tensile tests were conducted at room temperature and 750°C, respectively. The test results are shown in Table 2 below:

[0039] Depend on Figure 1 As can be seen from the test results in Table 2, the plasticity of the novel optimized alloy designed in this application is significantly higher than that of the existing GH3536 alloy.

[0040] In summary, this invention, by adding Ta and B elements according to the above technical solution, changes the solid solution atomic radius, reduces stacking fault energy, and optimizes the morphology and size of carbides, thereby reducing grain boundary energy and obtaining a composition that combines high plasticity and strength. This achieves the goal of optimizing the composition of a nickel-based superalloy that combines high plasticity and strength. The above description is merely a preferred embodiment of this invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

[0041] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A high-ductility nickel-based superalloy containing Ta, characterized in that, The alloy comprises the following components by mass percentage: Cr: 20.5–23.0 wt%, Co: 0.5–2.5 wt%, Mo: 7.0–10.0 wt%, W: 0.2–1.0 wt%, Fe: 17.0–20.0 wt%, Mn: 0–1 wt%, C: 0.05–0.15 wt%, Ta: 0.5–5.0 wt%, B: 0.03 wt%, with the balance being Ni. The alloy exhibits a room temperature elongation greater than 55% and a strength greater than 670 MPa, making it suitable for high-temperature alloy plates, strips, foils, and other forged parts.

2. The Ta-containing high-ductility nickel-based superalloy according to claim 1, characterized in that, The composition includes the following components by mass percentage: Cr: 20.8 wt%; Co: 2.5 wt%; Mo: 8.3 wt%. W: 0.9wt% C: 0.07wt%; Fe: 18.6wt%; Mn: 0.55wt%; Ta: 0.5wt%, B: 0.03wt%, balance Ni.

3. The Ta-containing high-ductility nickel-based superalloy according to claim 1, characterized in that, The composition includes the following components by mass percentage: Cr: 20.8 wt%; Co: 2.5 wt%; Mo: 8.3 wt%; W: 0.9wt% C: 0.07wt%; Fe: 18.6wt%; Mn: 0.55wt%; Ta: 5wt%, B: 0.03wt%, balance Ni.

4. A method for preparing a Ta-containing high-ductility nickel-based superalloy as described in claim 1, 2, or 3, characterized in that, Includes the following steps: S1. Remove the oxide scale from the surface of Ni, Mo, Co, Fe, and Cr metal particles and then perform ultrasonic vibration cleaning in anhydrous ethanol: S2. Place the cleaned metal raw material into a consumable vacuum arc furnace, a non-consumable vacuum arc furnace, or a vacuum suspension melting furnace, and evacuate the vacuum to 3×10⁻⁶. -3 Stop when the pressure drops below pa and then purge with high-purity argon as a protective atmosphere; S3. Under vacuum or argon atmosphere conditions, the consumable electrode is melted by the high temperature generated by electric arc discharge or by heating with induced current to melt the metal raw material into an alloy. The melting process is repeated 3 to 4 times to ensure uniform alloy composition. After the master alloy is melted uniformly, it is injected into a mold to obtain an ingot with a regular shape. S4. The prepared alloy composition is rolled and then heat-treated, followed by tensile tests at room temperature and 750℃ to finally prepare a high-plasticity nickel-based high-temperature alloy containing Ta.

5. The optimized design method for Ta-containing high-ductility nickel-based superalloys according to claim 4, characterized in that, In the tensile test described in step S4, the room temperature tensile rate is 1×10⁻⁶. -3 s -1 The tensile speed at 750℃ is 1.8 mm / min.

6. The method for preparing a Ta-containing high-ductility nickel-based superalloy according to claim 4, characterized in that, In step S3, the rolling process involves hot rolling a 16mm ingot to 2.4mm at 1160℃, annealing it at 1160℃ for 1 hour, and then cold rolling it to 1.2mm.

7. The method for preparing a Ta-containing high-ductility nickel-based superalloy according to claim 4, characterized in that, In step S3, the heat treatment involves solution treatment at 1150°C for 10 minutes followed by water cooling.

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