Nickel-based single crystal superalloys resistant to thin wall and coating damage, methods of making, and workpieces

Abstract

The application provides a nickel-based single crystal superalloy resistant to thin-wall and coating damage, a preparation method thereof and a workpiece. The alloy aims at the deficiencies of existing high Re alloys in cost, density and organizational stability, constructs a microstructure with L12 ordered γ' phase (Ni3(Al, Ta)) as a strengthening phase and stable organization by controlling the Re content at a low level and optimizing the main elements such as Ta, Co, Cr, W, Mo and trace impurities, which helps to reduce the alloy density and TCP phase precipitation tendency, improves the mechanical properties of the material in the thin-wall state, relieves the thin-wall damage effect, improves the adaptability of the alloy to the protective coating process, reduces the performance attenuation caused by the coating, so that the alloy has good creep life in the thin-wall and coating state, and is suitable for manufacturing key hot end components of aero-engines and gas turbines.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy materials, and more particularly to a nickel-based single-crystal high-temperature alloy resistant to thin-walled and coating damage, its preparation method, and the workpiece thereof. Background Technology

[0002] Improving the thrust-to-weight ratio of aero-engines and the thermal efficiency of heavy-duty gas turbines requires continuously increasing the turbine inlet gas temperature. This places higher demands on the material properties of hot-end components such as turbine blades, which directly withstand harsh operating environments including high temperatures, high stress, and oxidation corrosion. Nickel-based single-crystal superalloys, through directional solidification technology that eliminates transverse grain boundaries, possess excellent high-temperature creep strength, thermal fatigue resistance, and comprehensive performance, making them a primary structural material for manufacturing advanced aero-engine and gas turbine turbine blades.

[0003] To meet the cooling requirements at high temperatures, modern turbine blades often employ complex internal hollow air-cooled structures, resulting in a reduction in the wall thickness of the effective load-bearing section, typically no more than 1.5 mm, and sometimes even as low as 0.5 mm in some areas. When the geometric wall thickness of a component is reduced to a scale close to that of the material's microstructure characteristics (such as the spacing between primary dendrite arms, typically in the range of 300 μm to 500 μm), the material's mechanical behavior exhibits a significant size effect. Compared to standard-sized specimens, the mechanical properties such as creep rupture and fatigue strength in thin-walled regions show a decline, and the data dispersion increases. This phenomenon is known in engineering as the "thin-wall damage effect."

[0004] Furthermore, to improve resistance to high-temperature oxidation and hot corrosion, turbine blade surfaces typically require protective coatings (such as aluminized coatings or thermal barrier coatings). However, the coating preparation process and subsequent service life can negatively impact the base alloy, leading to a decline in base alloy performance, a phenomenon known as "coating process damage." Particularly for third-generation single-crystal superalloys with high Re content, TCP phases are prone to precipitate in the interdiffusion region between the coating and the substrate, affecting the alloy's microstructure stability and long-term service performance. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a nickel-based single-crystal superalloy resistant to thin-wall and coating damage, its preparation method and workpiece, wherein the alloy improves the thin-wall mechanical properties of the alloy while maintaining high-temperature strength and creep performance, and reduces the impact of coating process on substrate properties.

[0006] Existing high-Re third-generation nickel-based single-crystal superalloys have the following technical problems in engineering applications:

[0007] First, there's the issue of cost and density. Re is expensive and has a high density. A high Re content not only increases the cost of raw materials but also significantly increases the density of the alloy, thereby increasing the centrifugal load on high-speed rotating components.

[0008] Second, there is the issue of microstructural stability. High Re content increases the tendency for the alloy to precipitate TCP phase during long-term high-temperature service. These hard and brittle phases, rich in refractory elements such as Re, W, and Mo, will consume solid solution strengthening elements in the matrix and may act as crack initiation sources, affecting the long-term microstructural stability and service reliability of alloy components.

[0009] Third, there is the issue of thin-wall adaptability. Existing alloy design and evaluation systems are mostly based on standard-sized specimens, while modern turbine blades often employ complex hollow air-cooled structures with thin walls (often less than 1.5 mm, or even as thin as 0.5 mm). When the component wall thickness is close to the microstructural characteristic scale of the material (such as the primary dendrite arm spacing, typically 300 μm to 500 μm), the material's mechanical properties exhibit a decrease relative to standard specimens and increased data dispersion, a phenomenon known as the "thin-wall damage effect." The limited number of dendrites contained in thin-walled sections makes the material properties more sensitive to microstructural uniformity and metallurgical defects.

[0010] Fourth, the adaptability of coating processes. To improve resistance to oxidation and corrosion, blade surfaces typically require a protective coating. The coating preparation process (such as high-temperature diffusion annealing) and element interdiffusion during service can easily lead to coarsening, re-dissolution, or precipitation of harmful phases at the γ′ phase interface with the matrix alloy, resulting in a decline in matrix performance. For high-Re alloys with a high tendency for TCP phase precipitation, element segregation at the coating interface is more likely to cause microstructural instability.

[0011] Based on this, this application provides a nickel-based single-crystal superalloy resistant to thin-walled and coating damage, comprising, by weight percentage: 3.4%≤Re≤3.8%, 9.5%≤Co≤10.5%, 3.5%≤Cr≤4.5%, 1.3%≤Mo≤1.7%, 6.8%≤W≤7.2%, 5.6%≤Al≤6.2%, 7.0%≤Ta≤8.5%, 0.05%≤Hf≤0.20%, 0.003%≤C≤0.03%, 0≤B≤0.0025%, and 0≤S≤0.0%. 0.001%, 0≤P≤0.002%, 0≤O≤0.0008%, 0≤N≤0.0008%, 0≤Pb≤0.0002%, 0≤Bi≤0.00002%, 0≤Ti≤0.1%, 0≤Ru≤0.1%, 0≤Y≤0.002%, 0≤H≤0.001%, 0≤Si≤0.04%, 0≤Cu≤0.005%, 0≤Fe≤0.25%, 0≤Mn≤0.01%, 0≤V≤0.1%, 0≤K≤0.001%, 0≤Zr≤0.0 1%, 0≤Zn≤0.0005%, 0≤Pt≤0.08%, 0≤Mg≤0.003%, 0≤Se≤0.0002%, 0≤Te≤0.0001%, 0≤Th≤0.0003%, 0≤Tl≤0.00003%, 0≤As≤0.0005%, 0≤Ag≤0.0002%, 0≤Ca≤0.005%, 0≤Cd≤0.0002%, 0≤Cl≤0.0002%, 0≤Ga≤0.0015%, 0≤Ge≤0.0005%. 0≤Au≤0.0005%, 0≤In≤0.00002%, 0≤Na≤0.002%, 0≤Sb≤0.0002%, 0≤Sn≤0.0015%, 0≤Hg≤0.005%, 0≤U≤0.005%, 0≤Nb≤0.1%, 0≤La≤0.002%, 0≤Ce≤0.002%, 0≤Sc≤0.002%, 0≤Pd≤0.00001%, 0≤Be≤0.00001%, 0≤Sr≤0.00001% and the balance Ni.

[0012] The nickel-based single-crystal superalloy provided in this application, which is resistant to thin-wall and coating damage, has a high-temperature strength level comparable to or even exceeding that of existing third-generation alloys. It also has the properties of resisting thin-wall damage and coating process damage, and has multiple advantages such as low cost, low density and high microstructure stability.

[0013] In some specific implementations, the weight ratio of W to Re is 1.90 to 2.10; the weight ratio of Co to Re is 2.6 to 2.9.

[0014] In some specific implementations, the ratio of the total weight of Al and Ta to the total weight of W, Mo and Re is 1.10 to 1.25.

[0015] In some specific implementations, the weight ratio of Ta to the total weight of W and Mo is 0.82~0.96. In some specific implementations, the total content of O, N, and S is ≤10ppm.

[0016] In some specific implementations, the standard specimens made of the alloy have a creep rupture life of not less than 240 hours under 1100℃ / 137MPa conditions and a creep rupture life of not less than 140 hours under 980℃ / 300MPa conditions.

[0017] This application also provides a method for preparing the nickel-based single-crystal superalloy described in the above technical solution, comprising the following steps:

[0018] 1) The metal raw materials are melted, refined, and cast sequentially to obtain alloy ingots;

[0019] 2) The alloy ingot is subjected to directional solidification single crystal casting to obtain a single crystal casting;

[0020] 3) The single crystal casting is heat-treated to obtain a nickel-based single crystal high-temperature alloy.

[0021] In some specific implementations, step 2) specifically includes:

[0022] The alloy ingot is remelted, and the remelted alloy liquid is poured at a pouring temperature of 1500℃~1520℃. Then, the alloy liquid is directionally solidified from bottom to top at a pulling rate of 3mm / min~4mm / min to obtain a single crystal casting.

[0023] In some specific implementations, the heat treatment includes:

[0024] 1) Multi-stage solution treatment: Hold the single crystal casting at 1270℃±5℃ for 1h~3h, raise the temperature to 1300℃±5℃ and hold for 1h~3h, raise the temperature to 1310℃±5℃ and hold for 3h~5h, raise the temperature to 1320℃±5℃ and hold for 3h~5h, raise the temperature to 1325℃±5℃ and hold for 8h~12h, and cool to room temperature after the holding period.

[0025] 2) First-level aging treatment: Heat the solution-treated alloy to 1130℃±5℃, hold for 4h~6h, and cool to room temperature;

[0026] 3) Secondary aging treatment: The alloy that has undergone primary aging treatment is heated to 870℃±5℃, held for 20h~28h, and then cooled to room temperature.

[0027] This application also provides a workpiece comprising the nickel-based single-crystal superalloy described in the above technical solution or the nickel-based single-crystal superalloy prepared by the method described in the above technical solution.

[0028] The nickel-based single-crystal superalloy described in this application achieves a stable microstructure through compositional optimization. This microstructure is based on a face-centered cubic γ-phase matrix, with a high volume fraction of L12 ordered γ′ phase (Ni3(Al, Ta)) as the main reinforcing phase. By synergistically controlling the proportions of alloying elements such as Al, Ta, W, and Mo, the thermal stability of the γ′ phase is improved, and the tendency for the alloy to precipitate harmful TCP phases under long-term high-temperature and high-stress service conditions is suppressed. This highly stable microstructure is the physical basis for the alloy's resistance to thin-wall damage and coating process damage.

[0029] The nickel-based single-crystal superalloy, its preparation method, and the workpiece provided in this application have the following advantages compared to the prior art:

[0030] 1. Improved mechanical properties of thin-walled components and mitigation of size effects. Thanks to its high intrinsic microstructure stability, this alloy can maintain good microstructure uniformity in thin-walled sections (e.g., wall thickness less than 1.5 mm), reducing sensitivity to micro-defects and thus effectively resisting the "thin-wall damage effect," improving the performance consistency and reliability of thin-walled components under service conditions.

[0031] 2. Improved adaptability to coating processes. The alloy substrate exhibits good stability during thermal cycling in the preparation of the protective coating and during element interdiffusion in service, which slows down the degradation rate of the substrate structure at the coating interface and reduces the attenuation of the substrate's mechanical properties caused by the coating process.

[0032] 3. A balance between low cost, low density, and high performance is achieved. This application significantly reduces the Re content (controlled at 3.4%~3.8%), thereby lowering alloy density and raw material costs, while maintaining high high-temperature strength and creep resistance through synergistic strengthening of the composition. Experimental results show that the alloy exhibits good overall performance in both thin-walled and coated states, and possesses excellent oxidation and hot corrosion resistance, making it suitable for manufacturing key hot-end components such as turbine blades for aero-engines and gas turbines. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the preparation process of nickel-based single-crystal superalloys provided in the embodiments of this application;

[0034] Figure 2 This is a typical metallographic representation of the nickel-based single-crystal superalloy prepared in Example 1 of this application;

[0035] Figure 3The SEM microstructure of the nickel-based single-crystal superalloy prepared in Example 1 of this application;

[0036] Figure 4 This is a comparative bar chart showing the standard creep performance of the nickel-based single-crystal superalloy of Example 1 of the present invention and the comparative alloy under the conditions of 1100℃ / 137MPa and 980℃ / 300MPa.

[0037] Figure 5 A bar chart comparing the creep performance of thin-walled nickel-based single-crystal superalloys under different conditions (uncoated, 30μm aluminized, and 50μm aluminized) at 1050℃ / 120MPa and the percentage reduction in performance.

[0038] Figure 6 A bar chart comparing the creep life and performance reduction rate of thin-walled nickel-based single-crystal superalloys under different conditions (uncoated, 30μm aluminized, and 50μm aluminized) at 980℃ / 220MPa. Detailed Implementation

[0039] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0040] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0041] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0042] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and does not constitute a limitation on the scope of the invention. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0043] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0044] This application provides a nickel-based single-crystal superalloy resistant to thin-walled and coating damage, comprising, by weight percentage: 3.4%≤Re≤3.8%, 9.5%≤Co≤10.5%, 3.5%≤Cr≤4.5%, 1.3%≤Mo≤1.7%, 6.8%≤W≤7.2%, 5.6%≤Al≤6.2%, 7.0%≤Ta≤8.5%, 0.05%≤Hf≤0.20%, 0.003%≤C≤0.03%, 0≤B≤0.0025%, and 0≤S≤0.0001%. %, 0≤P≤0.002%, 0≤O≤0.0008%, 0≤N≤0.0008%, 0≤Pb≤0.0002%, 0≤Bi≤0.00002%, 0≤Ti≤0.1%, 0≤Ru≤0.1%, 0≤Y≤0.002%, 0≤H≤0.001%, 0≤Si≤0.04%, 0≤Cu≤0.005%, 0≤Fe≤0.25%, 0≤Mn≤0.01%, 0≤V≤0.1%, 0≤K≤0.001%, 0≤Zr≤0.01% , 0≤Zn≤0.0005%, 0≤Pt≤0.08%, 0≤Mg≤0.003%, 0≤Se≤0.0002%, 0≤Te≤0.0001%, 0≤Th≤0.0003%, 0≤Tl≤0.00003%, 0≤As≤0.0005%, 0≤Ag≤0.0002%, 0≤Ca≤0.005%, 0≤Cd≤0.0002%, 0≤Cl≤0.0002%, 0≤Ga≤0.0015%, 0≤Ge≤0.0005%, 0 ≤Au≤0.0005%, 0≤In≤0.00002%, 0≤Na≤0.002%, 0≤Sb≤0.0002%, 0≤Sn≤0.0015%, 0≤Hg≤0.005%, 0≤U≤0.005%, 0≤Nb≤0.1%, 0≤La≤0.002%, 0≤Ce≤0.002%, 0≤Sc≤0.002%, 0≤Pd≤0.00001%, 0≤Be≤0.00001%, 0≤Sr≤0.00001% and the balance Ni.

[0045] The microstructure of the nickel-based single-crystal superalloy provided in this application uses a high-volume-fraction, high-thermal-stability L12 ordered γ′ phase (Ni3(Al,Ta)) as a reinforcing skeleton, surrounded by a reinforced face-centered cubic γ matrix phase, which can effectively resist thin-wall damage and coating process damage.

[0046] The nickel-based single-crystal superalloy provided in this application comprises: 3.4% ≤ Re ≤ 3.8%. This application controls the Re content to be between 3.4% and 3.8%. Re, as an effective solid solution strengthening element, is mainly distributed in the γ matrix, hindering dislocation movement through the resulting lattice distortion and improving the alloy's high-temperature creep performance. Compared with traditional third-generation single-crystal superalloys with a typical Re content of 4.5% to 6%, the low Re design (3.4% to 3.8%) in this application, while ensuring high-temperature strength, has the following technical effects: Firstly, it reduces the alloy density (theoretical density can be controlled at 8.95 g / cm³). 3 The following are the benefits: 1) It reduces the cost of raw materials; 2) It reduces the supersaturation of TCP phase precipitation during long-term high-temperature service. Since the interdiffusion zone at the thin-walled section and coating interface is usually a sensitive area for TCP phase precipitation, reducing the Re content essentially improves the microstructure stability of the alloy, thereby improving the service reliability of thin-walled components. In some specific embodiments, the Re content is preferably 3.5%~3.7%, more preferably 3.55%~3.65%.

[0047] The nickel-based single-crystal superalloy provided in this application comprises 9.5% ≤ Co ≤ 10.5%. Co can increase the solid solution temperature of the γ′ phase and reduce the stacking fault energy of the γ matrix. In some preferred embodiments, the weight ratio of Co to Re is controlled to be 2.6~2.9, preferably 2.7~2.8. The synergistic effect of Co and Re within this ratio range can optimize the solid solution strengthening level and stacking fault energy of the matrix channels, improve the low-cycle and high-cycle fatigue performance of the alloy, and enable the alloy to achieve fatigue performance at 980℃ comparable to that of typical second-generation / third-generation commercial single-crystal alloys, meeting the service requirements of thin-walled blades under complex stress states. In some specific embodiments, the content of Co is preferably 9.6%~10.4%, more preferably 9.8%~10.2%.

[0048] The nickel-based single-crystal superalloy provided in this application comprises 3.5% ≤ Cr ≤ 4.5%. Cr is a key element ensuring the alloy's oxidation resistance and hot corrosion resistance. This content range provides the necessary environmental resistance (such as meeting the requirements for oxidation resistance at 1100℃ and hot corrosion resistance at 850℃) while avoiding the promotion of TCP phase precipitation or the reduction of γ′ phase solid solution temperature due to excessive Cr. In some specific embodiments, the Cr content is preferably 3.8%~4.2%, more preferably 3.9%~4.1%.

[0049] The nickel-based single-crystal superalloy provided in this application comprises: 1.3% ≤ Mo ≤ 1.7%, and 6.8% ≤ W ≤ 7.2%. W and Mo are the main refractory solid solution strengthening elements. While reducing the Re content, this application maintains the high-temperature strength of the alloy by optimizing the ratio of W, Mo, and Re. In particular, controlling the weight ratio of W to Re to be 1.90~2.10 ensures that the alloy still has sufficient solid solution strengthening ability under low Re conditions, enabling the standard sample to have a creep rupture life of not less than 240 hours under 1100℃ / 137MPa conditions, and effectively suppressing the precipitation of W- and Re-rich TCP phases. In some specific embodiments, the Mo content is preferably 1.4%~1.6%, more preferably 1.45%~1.55%; the W content is preferably 6.9%~7.1%, more preferably 6.95%~7.05%.

[0050] The nickel-based single-crystal superalloy provided in this application comprises 5.6% ≤ Al ≤ 6.2% and 7.0% ≤ Ta ≤ 8.5%. Al and Ta are both γ′ phase forming elements, with Ta exhibiting a stronger strengthening effect than Al. This application improves the solid solution temperature and antiphase domain boundary energy of the γ′ phase through a high Ta design (7.0%~8.5%). To ensure microstructure stability and coating adaptability, this application specifically controls the weight ratio of Al and Ta to the weight ratio of W, Mo, and Re to be 1.10~1.25, and the weight ratio of Ta to the weight ratio of W and Mo to be 0.82~0.96. These specific component ratios improve the thermal stability of the γ′ phase. When the alloy undergoes high-temperature aluminizing or coating diffusion treatment, it slows down the coarsening, re-dissolution, or rafting rate of the matrix γ′ phase, thereby reducing "coating process damage" and maintaining the mechanical properties of the alloy in the coated state. In some specific embodiments, the content of Al is preferably 5.7% to 6.1%, more preferably 5.8% to 6.0%; the content of Ta is preferably 7.5% to 8.0%, more preferably 7.6% to 8.0%.

[0051] The nickel-based single-crystal superalloy provided in this application comprises: 0.05% ≤ Hf ≤ 0.20%, 0.003% ≤ C ≤ 0.03%, and 0 ≤ B ≤ 0.0025%. Hf mainly segregates at grain boundaries and oxide / alloy interfaces, improving oxide film adhesion and enhancing anti-stripping ability through a pinning effect. In some specific embodiments, the Hf content is preferably 0.08%~0.15%, more preferably 0.10%~0.12%. C can form a small amount of carbides, strengthening small-angle grain boundaries. In some specific embodiments, the C content is preferably 0.005%~0.02%, more preferably 0.01%~0.015%. An appropriate amount of B helps strengthen grain boundaries, but excessive B will lower the alloy's initial melting temperature. In some specific embodiments, the B content is preferably 0~0.002%, more preferably 0~0.001%.

[0052] The nickel-based single-crystal superalloy provided in this application also limits the content of the following elements: 0≤S≤0.0001%, 0≤P≤0.002%, 0≤O≤0.0008%, 0≤N≤0.0008%, 0≤Pb≤0.0002%, 0≤Bi≤0.00002%, 0≤Ti≤0.1%, 0≤Ru≤0.1%, 0≤Y≤0.002%, 0≤H≤0.001%, 0≤Si≤0.04%, 0≤Cu≤0.005%, 0≤Fe≤0.25%, 0≤Mn≤0.01%, 0≤V≤0.1%, 0≤K≤0.001%, 0≤Zr≤0.01%, 0≤Zn≤0.0005%, 0≤Pt≤0.08%, 0≤Mg≤0.003%, 0≤Se≤0.0002%, 0≤Te≤0.0001%, 0≤Th≤0.0002%. 0.0003%, 0≤Tl≤0.00003%, 0≤As≤0.0005%, 0≤Ag≤0.0002%, 0≤Ca≤0.005%, 0≤Cd≤0.0002%, 0≤Cl≤0.0002%, 0≤Ga≤0.0015%, 0≤Ge≤0.0005%, 0≤Au≤0.0005%, 0≤In≤0.00002%, 0≤Na≤0 0.002%, 0≤Sb≤0.0002%, 0≤Sn≤0.0015%, 0≤Hg≤0.005%, 0≤U≤0.005%, 0≤Nb≤0.1%, 0≤La≤0.002%, 0≤Ce≤0.002%, 0≤Sc≤0.002%, 0≤Pd≤0.00001%, 0≤Be≤0.00001%, 0≤Sr≤0.00001%.

[0053] In some specific implementations, the total content of O, N, and S is ≤10ppm. S is an extremely harmful surface-active element in high-temperature alloys, which tends to segregate at the oxide film / substrate interface, reducing the adhesion of the oxide film. By maintaining S, O, and N at extremely low levels, the enrichment of impurity elements at the coating and oxide film interfaces can be reduced, improving the oxide film's resistance to peeling, thereby ensuring that the alloy reaches a fully oxidation-resistant level at a high temperature of 1100℃.

[0054] Specifically, this application imposes strict ultra-low content control on low-melting-point or harmful impurity elements such as Pb, Bi, Tl, Se, Te, As, Ag, and Cd (e.g., Pb ≤ 2 ppm, Bi ≤ 0.2 ppm). These elements readily segregate between dendrites or at small-angle grain boundaries, causing grain boundary embrittlement or forming low-melting-point liquid films at high temperatures, leading to "liquefaction cracks." Strictly limiting these elements helps prevent interface cracking during the heat treatment process of coating preparation or during high-temperature service, playing a crucial role in maintaining the mechanical integrity of thin-walled components in the coated state.

[0055] Thin-walled components have small cross-sectional dimensions and a limited number of dendrites, making their mechanical behavior highly sensitive to the uniformity of their microstructure and metallurgical defects. Individual micro-metallurgical defects (such as non-metallic inclusions or segregated phases) are more likely to become crack initiation sources under thin-walled conditions, leading to a sharp decline in performance. This application reduces the probability of intrinsic metallurgical defects and brittle phase formation by strictly controlling impurity elements such as S, P, Sn, and Sb, as well as residual elements such as Si and Fe. This improves the performance consistency and reliability of thin-walled components, making them more suitable for the service requirements of complex cooling structures.

[0056] As a further optimization of the technical solution of this application, the nickel-based single-crystal superalloy possesses the following excellent performance characteristics:

[0057] The standard sample made of the nickel-based single crystal superalloy has a creep life of not less than 240 hours under 1100℃ / 137MPa conditions and not less than 140 hours under 980℃ / 300MPa conditions.

[0058] The thin-walled sample made of the nickel-based single-crystal superalloy exhibits superior creep rupture life compared to typical third-generation nickel-based single-crystal superalloys under conditions of 1050℃ / 120MPa, in the uncoated state, the state with 30μm of surface aluminization, and the state with 50μm of surface aluminization. Under conditions of 980℃ / 220MPa, when the surface aluminization reaches 50μm, the performance reduction due to the aluminization process is less than that of typical third-generation nickel-based single-crystal superalloys under the same conditions, and its absolute creep rupture life value is superior to that of typical third-generation nickel-based single-crystal superalloys.

[0059] The high-cycle fatigue performance of the alloy at 980℃ is comparable to that of typical second- and third-generation nickel-based single-crystal superalloys such as DD6 and DD9.

[0060] The alloy exhibits fully oxidation-resistant properties at 1100℃ and its salt-coated hot corrosion resistance at 850℃ is superior to that of typical third-generation nickel-based single-crystal high-temperature alloys.

[0061] The density of the alloy is less than 8.95 g / cm³. 3 .

[0062] This application also provides a workpiece comprising the nickel-based single-crystal superalloy described in the above technical solution or the nickel-based single-crystal superalloy prepared by the method described in the above technical solution.

[0063] The workpiece described in this application may be a high-pressure turbine blade (including working blades and guide blades). Such blades typically integrate complex internal cooling structures, such as multi-layer rotating cooling channels, double-wall cooling structures, or impact / film cooling composite holes.

[0064] In some specific implementations, the workpiece comprises a thin-walled structure, with the thickness of its nickel-based single-crystal superalloy matrix ranging from 0.1 mm to 2 mm, preferably from 0.5 mm to 1.5 mm. Tests show that the alloy provided in this application maintains good high-temperature creep life even when the wall thickness is reduced to below 2 mm, exhibiting low thin-wall damage sensitivity.

[0065] In some specific implementations, the workpiece further includes a protective coating, such as an aluminized layer, formed on the surface of a nickel-based single-crystal superalloy substrate. The thickness of the aluminized layer can be 10μm to 100μm, preferably 20μm to 80μm, and more preferably 30μm to 70μm. The alloy substrate provided in this application has good adaptability to thicker aluminized layers, and its high-temperature creep life does not deteriorate significantly after the coating is formed, meeting the service requirements of coated thin-walled components.

[0066] This application also provides a method for preparing the nickel-based single-crystal superalloy described in the above technical solution, comprising the following steps:

[0067] 1) The metal raw materials are melted, refined, and cast sequentially to obtain alloy ingots;

[0068] 2) The alloy ingot is subjected to directional solidification single crystal casting to obtain a single crystal casting;

[0069] 3) The single crystal casting is heat-treated to obtain a nickel-based single crystal high-temperature alloy.

[0070] This application uses metallic raw materials as raw materials, which are sequentially melted, refined, and cast to obtain alloy ingots. Specifically, this application uses metallic raw materials with a purity greater than 99.99% to control the amount of impurity elements and ensure the performance of the obtained alloy. This application first melts high-melting-point metals such as Ni, Co, Cr, W, Ta, and Mo, and then refines them to homogenize the composition and allow gases to escape. In some specific implementations, the refining temperature is 1540℃~1580℃, preferably 1550℃~1570℃, and the time is 30min~60min, preferably 40min~50min. At the end of the refining process, oxidizing and active elements such as Al, Hf, C, and B are added to adjust the composition. In some specific implementations, non-metallic elements such as C and B are used as raw materials along with the intermediate alloy; this application has no special restrictions on this. After the composition adjustment is completed, the molten metal is cast into a water-cooled copper mold to obtain an alloy ingot with a uniform composition and dense structure. In some specific implementations, the melting and refining are carried out in a vacuum induction melting furnace, which ensures the uniformity of the alloy's chemical composition and the aforementioned ultra-high purity through high vacuum and sufficient high-temperature refining time. In some specific implementations, the vacuum level is ≤10. -2 Pa.

[0071] After obtaining the alloy ingot, the alloy ingot is subjected to directional solidification single crystal casting to obtain a single crystal casting. Specifically, this includes:

[0072] The alloy ingot is remelted, and the remelted alloy liquid is poured at a pouring temperature of 1500℃~1520℃. Then, the alloy liquid is directionally solidified from bottom to top at a pulling rate of 3mm / min~4mm / min to obtain a single crystal casting.

[0073] Specifically, this application employs a high-gradient directional solidification method. First, the alloy ingot is remelted in a vacuum environment. Then, the molten alloy is poured into a mold shell. Finally, under the action of pulling, the casting solidifies directionally from bottom to top, forming a single-crystal casting. In some specific implementations, the mold shell is a ceramic mold shell, which can be a ceramic mold shell containing a ceramic core and having a spiral crystallization structure. In some specific implementations, the ceramic mold shell is an alumina-based ceramic mold shell. In some specific implementations, the pouring temperature is 1500℃~1520℃, preferably 1505℃~1510℃. In some specific implementations, it is preferred to preheat the mold shell to a temperature 100℃~150℃ higher than the alloy liquidus temperature, preferably 120℃~140℃. After pouring, the pulling rate is 3mm / min~4mm / min, preferably 3.2mm / min~3.8mm / min. After solidification, the principal stress axes and crystallographic... <001> Single-crystal castings with an orientation deviation angle within 10°. Using a slow drawing rate of 3mm / min to 4mm / min can form a fine dendritic structure with uniform spacing between primary dendrite arms, reducing as-cast segregation and laying the foundation for homogenization in subsequent solution heat treatment, while ensuring high precision in single-crystal orientation.

[0074] After demolding to obtain a single-crystal casting, it is subjected to heat treatment to obtain a nickel-based single-crystal superalloy. In some specific implementations, the heat treatment includes:

[0075] 1) Multi-stage solution treatment: Hold the single crystal casting at 1270℃±5℃ for 1h~3h, raise the temperature to 1300℃±5℃ and hold for 1h~3h, raise the temperature to 1310℃±5℃ and hold for 3h~5h, raise the temperature to 1320℃±5℃ and hold for 3h~5h, raise the temperature to 1325℃±5℃ and hold for 8h~12h, and cool to room temperature after the holding period.

[0076] 2) First-level aging treatment: Heat the solution-treated alloy to 1130℃±5℃, hold for 4h~6h, and cool to room temperature;

[0077] 3) Secondary aging treatment: The alloy that has undergone primary aging treatment is heated to 870℃±5℃, held for 20h~28h, and then cooled to room temperature.

[0078] Specifically, the cooling in the multi-stage solution treatment, first-stage aging, and second-stage aging treatment is independently air cooling.

[0079] In this application, a multi-stage solution treatment, employing a stepped heating strategy from 1270℃ to 1325℃, gradually eliminates low-melting-point eutectic structures and promotes the re-dissolution of coarse γ′ phases and interdendritic segregating elements (such as W and Re) to the γ matrix. The highest solution temperature is set at 1325℃, maximizing compositional homogenization and achieving a supersaturated solid solution while avoiding initial melting of the alloy. The subsequent first-stage aging (1130℃) precipitates uniformly sized, regularly arranged cubic γ′ phases, establishing the high-temperature strength foundation of the alloy; the second-stage aging (870℃) precipitates even finer secondary γ′ phases, further adjusting the dislocation movement resistance within the matrix channels. This heat treatment process yields an ideal microstructure for the alloy, ensuring its mechanical property stability in thin-walled and coated states.

[0080] See Figure 1 , Figure 1 A schematic diagram of the preparation process of nickel-based single-crystal superalloys provided in this application embodiment includes the following steps:

[0081] a) Preparation of master alloy:

[0082] The ingredients are prepared using high-purity metal raw materials with a purity > 99.99%, and the process is carried out under a vacuum degree ≤ 10. -2 Vacuum induction melting is carried out under Pa, followed by high-temperature refining at 1540℃~1580℃ for 30min~60min. After adding active elements such as Hf, C, and B to adjust the composition, the master alloy ingot is cast.

[0083] b) Directional solidification single crystal casting:

[0084] The master alloy ingot was remelted in a high-gradient directional solidification furnace, cast into a ceramic mold at 1500℃~1520℃, and then subjected to high-gradient directional solidification at a drawing rate of 3mm / min~4mm / min to obtain... <001> Oriented single-crystal castings;

[0085] c) Post-casting treatment and heat treatment:

[0086] After the single crystal casting is deshelled and decored, it undergoes heat treatment including multi-stage solution treatment, first-stage aging treatment and second-stage aging treatment to finally obtain a nickel-based single crystal high-temperature alloy component resistant to thin-wall damage.

[0087] After heat treatment, a nickel-based single-crystal superalloy is obtained. Metallographic and microstructural analyses were performed on the obtained nickel-based single-crystal superalloy. The results showed that the microstructure of the nickel-based single-crystal superalloy prepared in this application consists of a regularly morphologically regular, cubic γ′ phase and surrounding γ matrix channels. The density of the nickel-based single-crystal superalloy was measured using the Archimedes displacement method, and the results showed that its density was less than 8.95 g / cm³. 3 .

[0088] The high-temperature durability of the standard sample made from the nickel-based single-crystal superalloy provided in this application is not significantly different from that of the typical third-generation nickel-based single-crystal superalloy with high rhenium content. However, after being prepared into a thin-walled sample, its high-temperature durability is significantly better than that of the thin-walled sample prepared from the typical third-generation nickel-based single-crystal superalloy with high rhenium content. After being prepared into a thin-walled sample and forming an aluminized layer, its high-temperature durability is significantly better than that of the thin-walled sample prepared from the typical third-generation nickel-based single-crystal superalloy with high rhenium content.

[0089] Compared with the prior art, the nickel-based single-crystal superalloy resistant to thin-walled and coating damage and its preparation method provided in this application have the following significant advantages:

[0090] (1) High-temperature strength retention under low Re content is achieved: This application controls the Re content at 3.4%~3.8% (lower than the usual 5%~6% level of traditional third-generation alloys). Through synergistic strengthening with elements such as W, Mo, and Ta, the standard sample of the alloy has a creep life of not less than 240 hours under the condition of 1100℃ / 137MPa, which reaches the performance level of existing high-Re third-generation single crystal high-temperature alloys.

[0091] (2) Improved resistance to thin-wall damage and coating damage: Experiments show that, thanks to the optimized composition ratio and microstructure stability, the alloy provided in this application exhibits less mechanical property degradation in both thin-walled and coated states. Compared to typical third-generation single-crystal superalloys, this alloy demonstrates higher service reliability under thin-walled and coated conditions.

[0092] (3) Reduced material density and cost: By reducing the content of high-density, high-priced Re element, the alloy density provided in this application is controlled at 8.95 g / cm³. 3 Below (lower than 9.0 g / cm³ of some mainstream third-generation alloys) 3 This helps reduce the weight and centrifugal load of rotating components in aero engines. At the same time, the reduction in raw material costs improves the economic viability of the alloy.

[0093] (4) Improved long-term structural stability: The low Re composition design reduces the driving force for the precipitation of TCP phase during long-term high-temperature service of the alloy from a thermodynamic perspective. This helps to maintain the mechanical properties of the material after long-term service, especially in thin-walled sections and coating / matrix interdiffusion regions where element segregation is prone to occur, and can suppress the formation of brittle phases.

[0094] (5) Achieving a balance of comprehensive performance: While ensuring high-temperature creep performance, this alloy also takes into account good high-cycle fatigue performance, oxidation resistance and hot corrosion resistance, making it suitable for manufacturing hot-end components under complex working conditions.

[0095] (6) Good process stability: The preparation method provided in this application covers the whole process control from melting, directional solidification to heat treatment. The process parameters are clear, and it has good repeatability, making it suitable for industrial production.

[0096] The present invention is further illustrated below with reference to the embodiments. The scope of protection of the present invention is not limited to the following embodiments.

[0097] Examples 1-5, Comparative Examples 1-3

[0098] Nickel-based single-crystal superalloys were prepared according to the formulations shown in Table 1.

[0099] Table 1. Formulations (wt.%) of nickel-based single-crystal superalloys provided in the embodiments and comparative examples of this application.

[0100]

[0101] Table 2. Specific component proportions in nickel-based single-crystal superalloys provided in the embodiments and comparative examples of this application.

[0102]

[0103] The preparation method is as follows:

[0104] According to the proportions shown in Table 1, metallic raw materials (Ni, Co, Cr, Mo, W, Ta, Al, Re, Hf) with a purity higher than 99.99%, along with C and B as intermediate alloying agents, were selected. The raw materials were placed in a vacuum induction melting furnace with a vacuum degree better than 10⁻⁶. - Melting was carried out under conditions of 2 Pa. First, high-melting-point metals such as Ni, Co, Cr, W, Ta, and Mo were melted. After complete melting, the temperature was raised to 1560℃ for refining, and held for 45 minutes to ensure homogenization of the composition and gas escape. Subsequently, towards the end of the refining process, oxidizing and active elements such as Al, Hf, C, and B were added sequentially. After the composition adjustment was completed, the molten metal was poured into a water-cooled copper mold to obtain a master alloy ingot with uniform composition and dense structure. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to analyze the chemical composition of the master alloy ingot, confirming that its composition was within the target range and that the content of impurity elements met the specified upper limits.

[0105] The prepared master alloy ingot was remelted in a vacuum environment using a high-gradient directional solidification furnace. The molten alloy was heated to 1520°C using an alumina-based ceramic mold with a helical crystal structure, and then poured into the mold, which was preheated to 1500°C (approximately 120°C above the alloy's liquidus temperature). After pouring, a directional solidification process was initiated at a pulling rate of 3.5 mm / min, allowing the casting to solidify from bottom to top, yielding standard single-crystal test bars and standard single-crystal test plates.

[0106] After the standard single crystal test rod and standard single crystal test plate are deshelled and decored respectively, they are placed in a vacuum heat treatment furnace for heat treatment, as follows:

[0107] 1) Multi-stage solution treatment: Under vacuum, first heat to 1270℃ and hold for 2 hours; then heat to 1300℃ and hold for 2 hours; then heat to 1310℃ and hold for 4 hours; then heat to 1320℃ and hold for 4 hours; finally heat to 1325℃ for final solution treatment and hold for 10 hours. After the treatment, use air to quickly cool to room temperature.

[0108] 2) First-level aging treatment: The solution-treated alloy is reheated to 1130℃, held for 4 hours, and then air-cooled to room temperature.

[0109] 3) Secondary aging treatment: The alloy after primary aging treatment is heated to 870℃, held for 24 hours, and finally air-cooled to room temperature.

[0110] Standard single-crystal test plates were processed into thin-walled plate-shaped specimens with a wall thickness of 1.5 mm, which were then used as thin-walled samples for testing. Standard single-crystal test rods were used as standard sample samples for testing. All samples were examined by X-ray Laue diffraction, and their principal stress axes (long axes of the casting) and crystallographic properties were analyzed. <001> The deviation angles of the directions are all less than 8°, which meets the requirements for single crystal castings.

[0111] Metallographic analysis and SEM scanning were performed on the thin-walled nickel-based single-crystal superalloy sample prepared in Example 1. The results are shown in [reference needed]. Figure 2 and Figure 3 , Figure 2 This is a typical metallographic representation of the thin-walled nickel-based single-crystal superalloy sample prepared in Example 1 of this application; Figure 3 The image shows the SEM microstructure of the thin-walled nickel-based single-crystal superalloy sample prepared in Example 1 of this application.

[0112] Metallographic analysis showed that in the thin-walled nickel-based single-crystal superalloy sample prepared in Example 1 of this application, the primary dendrite arm spacing was approximately 350 μm to 400 μm, and the microporous volume fraction was less than 0.1%. After multi-stage solution treatment and two-stage aging heat treatment, the coarse, inhomogeneous eutectic γ′ phase and dendrite segregation in the as-cast microstructure were completely eliminated. The final microstructure consisted of a regularly shaped, cubic γ′ phase and surrounding γ matrix channels. Statistically, the γ′ strengthening phase was uniform in size, with an average side length of approximately 0.45 μm and a volume fraction as high as 70%. The γ / γ′ phase interface was clear and well-matched. No initial melting region caused by improper heat treatment was observed throughout the entire field of view, nor was any harmful TCP phase precipitation found. The density of the thin-walled nickel-based single-crystal superalloy samples prepared in Example 1 and Comparative Example 1 was measured using the Archimedes displacement method. The results showed that the measured density of the thin-walled nickel-based single-crystal superalloy sample prepared in Example 1 of this application was 8.94 g / cm³. 3 The measured density of the thin-walled nickel-based single-crystal superalloy sample prepared in Comparative Example 1 was 9.12 g / cm³. 3 .

[0113] The nickel-based single-crystal superalloy standard samples prepared in Example 1 and Comparative Example 1 were processed into smooth creep-delay test specimens, and high-temperature creep-delay life tests were conducted at 1100℃ / 137MPa and 980℃ / 300MPa, respectively. The test results are as follows: Figure 4 As shown, Figure 4 This is a bar chart comparing the standard creep performance of the nickel-based single-crystal superalloy of Example 1 of the present invention and a comparative alloy under conditions of 1100℃ / 137MPa and 980℃ / 300MPa. Figure 4 It is evident that, under extreme high-temperature conditions of 1100℃, the creep rupture lifetime of the nickel-based single-crystal superalloy standard sample prepared in Example 1 is comparable to that of the high-Re nickel-based single-crystal superalloy standard sample prepared in Comparative Example 1. At 980℃, the creep rupture lifetime of the nickel-based single-crystal superalloy standard sample prepared in Example 1 is slightly lower than that of the high-Re nickel-based single-crystal superalloy standard sample prepared in Comparative Example 1. This demonstrates that, while significantly reducing Re content and density, this application, through the synergistic strengthening of elements such as high Ta and W, fully achieves the high-temperature strength level of third-generation single-crystal alloys.

[0114] The thin-walled sample with a thickness of 1.5 mm prepared in Example 1 and the thin-walled sample with a thickness of 1.5 mm prepared in Comparative Example 1 were subjected to aluminizing. The aluminized protective coating with a thickness of 30 μm was obtained by holding at 1080 °C for 4 h using the vapor phase aluminizing process. The aluminized protective coating with a thickness of 50 μm was obtained by holding at 1080 °C for 6 h.

[0115] Creep cycles were performed on uncoated, 30μm aluminized, and 50μm aluminized thin-walled samples at 1050℃ / 120MPa and 980℃ / 220MPa, respectively. The results are as follows: Figure 5 and Figure 6 As shown, Figure 5 This is a bar chart comparing the creep rupture properties and the percentage reduction in properties of thin-walled nickel-based single-crystal superalloy samples under different conditions (uncoated, 30 μm aluminized, and 50 μm aluminized) at 1050℃ / 120MPa. Figure 6 This is a bar chart comparing the creep life and performance reduction rate of thin-walled nickel-based single-crystal superalloy samples under different conditions (uncoated, 30μm aluminized, and 50μm aluminized) at 980℃ / 220MPa.

[0116] like Figure 5 As shown, under conditions of 1050℃ / 120MPa, regardless of whether it is in the uncoated state or after aluminizing by 30μm and 50μm, the creep rupture life of the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 is significantly higher than that of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1, and the reduction rate is also significantly lower than that of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1. This directly proves that the alloy of the present invention has a stronger ability to resist thin-wall damage and coating damage.

[0117] like Figure 6 As shown, under conditions of 980℃ / 220MPa, after aluminizing to a depth of 50μm, the creep rupture lifetime of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1 dropped sharply from 964h without coating to 332h, representing a performance reduction of 65.6%. In contrast, the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 decreased from 556h to 416h, a performance reduction of only 25.1%. The performance degradation of the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 was significantly smaller than that of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1, and its absolute lifetime after coating (416h) was slightly higher than that of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1 (332h). These results demonstrate that this application, through its high Ta content design, effectively improved the thermal stability of the γ′ phase, successfully suppressed the damage to the substrate structure caused by the coating heat treatment process, and exhibited excellent resistance to coating process damage.

[0118] High-cycle fatigue testing (R=-1) at 980℃ showed that the fatigue strength of the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 was at the same level as that of alloys such as DD6 and DD9. After 1000 hours of cyclic oxidation testing (one cycle per hour) at 1100℃, the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 showed extremely low oxidation weight gain, with an intact oxide film and no peeling, reaching a level of complete oxidation resistance. Salt-coated hot corrosion testing at 850℃ showed that the corrosion depth of the nickel-based single-crystal superalloy thin-walled sample prepared in Example 1 was less than that of the nickel-based single-crystal superalloy thin-walled sample prepared in Comparative Example 1.

[0119] The performance results of each embodiment and comparative example obtained by testing according to the test method described above are shown in Table 3. Table 3 shows the performance results of each embodiment and comparative example.

[0120] Table 3 shows the performance results obtained from the tests of each embodiment and comparative example.

[0121]

[0122] As shown in Table 3:

[0123] In Comparative Example 1, the Re content was higher and the density was greater. Compared with Comparative Example 1, this application reduced the Re content, and the creep life of the nickel-based single crystal superalloy standard sample, thin-walled sample and aluminized thin-walled sample was slightly reduced. However, the creep life retention rate of the aluminized thin-walled sample was significantly improved.

[0124] In Comparative Example 2, the Ta / (W+Mo) ratio was too low, and the refractory element was excessive, which easily led to the precipitation of TCP. Compared with Comparative Example 2, this application maintained a high creep life of nickel-based single crystal superalloy standard sample, thin-walled sample, and thin-walled sample after aluminizing while maintaining a low Re content. Moreover, the creep life retention rate of the thin-walled sample after aluminizing was significantly improved.

[0125] In Comparative Example 3, the total amount of Al+Ta was insufficient, resulting in inadequate γ′ phase enhancement and thermal stability.

[0126] Example 6

[0127] Using the formulation and method of Example 1, the shell was replaced with the shell of an advanced high-pressure turbine working blade to prepare an advanced high-pressure turbine working blade. The blade integrates a complex three-dimensional cooling channel, including a double-walled structure and an impact / film cooling structure. The wall thickness at the thinnest part of the blade is only 0.6 mm.

[0128] The manufactured blades were comprehensively inspected using non-destructive testing techniques, including X-ray inspection and fluorescent penetrant testing. The results showed that the blade castings were internally dense, free of volumetric defects such as shrinkage porosity and shrinkage cavities; the surface was smooth and crack-free. Particularly in the structurally complex thin-walled areas, the casting outlines were clear, the dimensions were precise, and no defects caused by insufficient casting fluidity or stress concentration were found. This indicates that the alloy composition and preparation method provided by this invention have excellent casting performance and can fully meet the technical requirements for manufacturing modern thin-walled single-crystal turbine blades with extremely complex structures.

[0129] In summary, this invention, through innovative alloy composition design tailored to engineering application needs and supplemented by a complete set of precise, fully controlled manufacturing processes, has successfully developed a high-performance, low-Re third-generation nickel-based single-crystal high-temperature alloy. This alloy not only achieves high-temperature strength comparable to traditional high-Re alloys, but also boasts advantages in overcoming thin-wall damage, coating process damage, and reducing density and cost, providing crucial material support for the development of next-generation high-performance aero-engines and gas turbines.

[0130] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A nickel-based single-crystal superalloy resistant to thin-walled and coating damage, characterized in that, By weight percentage, it includes: 3.4%≤Re≤3.8%, 9.5%≤Co≤10.5%, 3.5%≤Cr≤4.5%, 1.3%≤Mo≤1.7%, 6.8%≤W≤7.2%, 5.6%≤Al≤6.2%, 7.0%≤Ta≤8.5%, 0.05%≤Hf≤0.20%, 0.003%≤C≤0.03%, 0≤B≤0.0025%, 0≤S≤0.0001%, 0≤P≤0.002%, 0≤O≤0.0 0.008%, 0≤N≤0.0008%, 0≤Pb≤0.0002%, 0≤Bi≤0.00002%, 0≤Ti≤0.1%, 0≤Ru≤0.1%, 0≤Y≤0.002%, 0≤H≤0.001%, 0≤Si≤0.04%, 0≤Cu≤0.005%, 0≤Fe≤0.25%, 0≤Mn≤0.01%, 0≤V≤0.1%, 0≤K≤0.001%, 0≤Zr≤0.01%, 0≤Zn≤0.0005% , 0≤Pt≤0.08%, 0≤Mg≤0.003%, 0≤Se≤0.0002%, 0≤Te≤0.0001%, 0≤Th≤0.0003%, 0≤Tl≤0.00003%, 0≤As≤0.0005%, 0≤Ag≤0.0002%, 0≤Ca≤0.005%, 0≤Cd≤0.0002%, 0≤Cl≤0.0002%, 0≤Ga≤0.0015%, 0≤Ge≤0.0005%, 0≤Au≤0. 0.0005%, 0≤In≤0.00002%, 0≤Na≤0.002%, 0≤Sb≤0.0002%, 0≤Sn≤0.0015%, 0≤Hg≤0.005%, 0≤U≤0.005%, 0≤Nb≤0.1%, 0≤La≤0.002%, 0≤Ce≤0.002%, 0≤Sc≤0.002%, 0≤Pd≤0.00001%, 0≤Be≤0.00001%, 0≤Sr≤0.00001% and the balance Ni.

2. The nickel-based single-crystal superalloy according to claim 1, characterized in that, The weight ratio of W to Re is 1.90 to 2.10; The weight ratio of Co to Re is 2.6 to 2.

9.

3. The nickel-based single-crystal superalloy according to claim 1, characterized in that, The ratio of the total weight of Al and Ta to the total weight of W, Mo and Re is 1.10 to 1.

25.

4. The nickel-based single-crystal superalloy according to claim 1, characterized in that, The ratio of the weight of Ta to the total weight of W and Mo is 0.82 to 0.

96.

5. The nickel-based single-crystal superalloy according to claim 1, characterized in that, The total content of O, N and S is ≤10ppm.

6. The nickel-based single-crystal superalloy according to any one of claims 1 to 5, characterized in that, The standard specimens made of the alloy have a creep rupture life of not less than 240 hours under 1100℃ / 137MPa conditions and a creep rupture life of not less than 140 hours under 980℃ / 300MPa conditions.

7. A method for preparing the nickel-based single-crystal superalloy according to any one of claims 1 to 6, comprising the following steps: 1) The metal raw materials are melted, refined, and cast sequentially to obtain alloy ingots; 2) The alloy ingot is subjected to directional solidification single crystal casting to obtain a single crystal casting; 3) The single crystal casting is heat-treated to obtain a nickel-based single crystal high-temperature alloy.

8. The preparation method according to claim 7, characterized in that, Step 2) specifically includes: The alloy ingot is remelted, and the remelted alloy liquid is poured at a pouring temperature of 1500℃~1520℃. Then, the alloy liquid is directionally solidified from bottom to top at a pulling rate of 3mm / min~4mm / min to obtain a single crystal casting.

9. The preparation method according to claim 8, characterized in that, The heat treatment includes: 1) Multi-stage solution treatment: Hold the single crystal casting at 1270℃±5℃ for 1h~3h, raise the temperature to 1300℃±5℃ and hold for 1h~3h, raise the temperature to 1310℃±5℃ and hold for 3h~5h, raise the temperature to 1320℃±5℃ and hold for 3h~5h, raise the temperature to 1325℃±5℃ and hold for 8h~12h, and cool to room temperature after the holding period. 2) First-level aging treatment: Heat the solution-treated alloy to 1130℃±5℃, hold for 4h~6h, and cool to room temperature; 3) Secondary aging treatment: The alloy that has undergone primary aging treatment is heated to 870℃±5℃, held for 20h~28h, and then cooled to room temperature.

10. A workpiece comprising the nickel-based single-crystal superalloy as described in any one of claims 1 to 6 or the nickel-based single-crystal superalloy prepared by the method described in any one of claims 7 to 9.

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