Nickel-based superalloy with long high-temperature low-cycle fatigue life, its preparation method and application

Abstract

The present invention belongs to the technical field of superalloys, and particularly relates to a nickel-based superalloy with a long high-temperature low-cycle fatigue life, a preparation method thereof, and an application thereof. A nickel-based superalloy with a long high-temperature low-cycle fatigue life disclosed by the present invention comprises: C: 0.08 to 0.2%, Cr: 7 to 10%, Co: 8.0 to 11%, W: 6 to 11%, Al: 5.2 to 8.0%, Ta: 2 to 3.6%, Mo: 0.1 to 1.5%, Hf: 0.6 to 1.8%, Ti: 0.8 to 2.5%, B: 0.005 to 0.03%, Zr: 0.001 to 0.08%, Mg: 0.005 to 0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.005 to 0.06%, Sr: ≤0.15%, and the balance being nickel and inevitable impurities, by mass percentage.

Description

Technical Field

[0001] The present invention belongs to the technical field of superalloys, and particularly relates to a nickel-based superalloy with a long high-temperature low-cycle fatigue life, a preparation method thereof, and an application thereof. Background Art

[0002] Nickel-based superalloys were first applied in the United States as key components in the hot section of aeroengines. This alloy is a kind of superalloy with nickel as the matrix and other alloying elements added, and has high strength, good oxidation resistance and corrosion resistance. Nowadays, nickel-based superalloys have been widely used in the manufacture of turbine blades for aeroengines and gas turbines. Turbine blades have complex shapes and are subjected to the erosion of high temperature, high pressure and high-speed gas for a long time. In addition, the strong centrifugal force generated by their own high-speed rotation will also cause various failure behaviors. In addition, during the start-up and shutdown processes of the engine, the blades are subjected to changing loads and temperatures, which cause low-cycle fatigue damage of the blades, thus causing fatigue aging. Therefore, the fatigue problem has become increasingly prominent.

[0003] With the development of aeroengines and gas turbines, higher requirements are put forward for the fatigue performance of nickel-based superalloys. There are many factors affecting the fatigue performance of nickel-based superalloys, such as internal defects and microstructures such as microvoids, carbides, residual eutectics, grain boundaries, surface defects caused by hot corrosion, coatings, crystal orientation, and external conditions. These factors will affect the stress distribution, dislocation movement, crack initiation and propagation behavior of nickel-based superalloys, thus affecting the low-cycle fatigue life of the alloy. Summary of the Invention

[0004] The present invention is made based on the inventor's discovery and understanding of the following facts and problems:

[0005] Nickel-based superalloys are a kind of superalloys with nickel as the matrix and other alloying elements added, and have high strength, good oxidation resistance and corrosion resistance. However, with the development of aeroengines and gas turbines, the fatigue failure problem of turbine blades has become increasingly significant, which puts forward higher requirements for the high-temperature mechanical properties and fatigue performance of nickel-based superalloys. Therefore, there is an urgent need to prepare nickel-based superalloys with more excellent high-temperature performance and longer fatigue life.

[0006] The embodiments of the present invention aim to solve at least one of the technical problems in the related art to some extent. For this reason, the embodiments of the present invention propose a nickel-based superalloy with a long high-temperature low-cycle fatigue life, which has excellent high-temperature performance, low-cycle fatigue life and creep life, and good processability, and can meet the use requirements of high-temperature and high-stress components of aeroengines and gas turbines.

[0007] The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to the embodiments of the present invention includes: C: 0.08-0.2%, Cr: 7-10%, Co: 8.0-11%, W: 6-11%, Al: 5.2-8.0%, Ta: 2-3.6%, Mo: 0.1-1.5%, Hf: 0.6-1.8%, Ti: 0.8-2.5%, B: 0.005-0.03%, Zr: 0.001-0.08%, Mg: 0.005-0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.005-0.06%, Sr: ≤0.15%, and the balance is nickel and inevitable impurities, by mass percentage.

[0008] The advantages and technical effects brought by the nickel-based superalloy with a long high-temperature low-cycle fatigue life according to the embodiments of the present invention are as follows: 1. In the embodiments of the present invention, the addition of elements W, Mo, and Co for solution strengthening can improve the high-temperature strength of the alloy. In addition, by adding three γ'-phase forming elements Al, Ti, and Ta, the alloy has a nano-scale γ'-phase stably existing at 900-950°C, having a precipitation strengthening effect. Then, by reasonably matching the grain boundary strengthening elements C, B, Zr, and Sr, the high-temperature performance and fatigue life of the nickel-based alloy are significantly improved; 2. In the embodiments of the present invention, the added element Ru is an element with a weak segregation tendency, which can effectively inhibit the precipitation of the TCP phase, facilitating the combined action with other elements to enhance the mechanical properties of the alloy; 3. In the embodiments of the present invention, the added element Sr can form dispersed intermetallic compounds during smelting, which are pinned at the grain boundaries, hindering the movement of dislocations, and enhancing the high-temperature performance and fatigue performance of the alloy; 4. In the embodiments of the present invention, the tensile strength of the alloy at 950°C can reach 1108 MPa, the yield strength can reach 845 MPa, the elongation after fracture is as high as 14.7%, the low-cycle fatigue life can be as high as 4900 times, no forging shrinkage holes are generated, and it has good processing performance, capable of meeting the requirements of the design and use of advanced aero-engines and gas turbines.

[0009] In some embodiments, Ta, W, and Al satisfy the relational expression 1.22 ≤ Ta - 0.45W / Al ≤ 2.14, where Ta, W, and Al are the values after removing the percentage sign of the mass percentage contents of elements Ta, W, and Al in the nickel-based superalloy.

[0010] In some embodiments, Mo, Ru, and C satisfy the relational expression 0.5 < 2Mo - 3Ru / C < 2.75, where Mo, Ru, and C are the values after removing the percentage sign of the mass percentage contents of elements Mo, Ru, and C in the nickel-based superalloy.

[0011] In some embodiments, Hf, Mg, Sr, and Ru satisfy the relational expression 0.08 < (Sr + Ru) / (Hf + Mg) < 0.23, where Hf, Mg, Sr, and Ru are the values obtained by removing the percentage signs from the mass percentage contents of the elements Hf, Mg, Sr, and Ru in the nickel-based superalloy.

[0012] In some embodiments, the nickel-based superalloy with a long high-temperature low-cycle fatigue life includes: C: 0.08 - 0.2%, Cr: 7 - 9.7%, Co: 8.0 - 11%, W: 6.4 - 10.8%, Al: 5.2 - 8.0%, Ta: 2.0 - 3.5%, Mo: 0.5 - 1.5%, Hf: 0.6 - 1.8%, Ti: 0.8 - 2.5%, B: 0.005 - 0.03%, Zr: 0.002 - 0.08%, Mg: 0.005 - 0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.01 - 0.06%, Sr: 0.02 - 0.15%, and the balance is nickel and unavoidable impurities.

[0013] In some embodiments, the nickel-based superalloy with a long high-temperature low-cycle fatigue life includes: C: 0.12 - 0.18%, Cr: 8.5 - 9.5%, Co: 10.5 - 10.7%, W: 8.6 - 10.5%, Al: 5.8 - 6.0%, Ta: 2.2 - 2.7%, Mo: 1 - 1.2%, Hf: 1.2 - 1.3%, Ti: 1.6 - 2%, B: 0.005 - 0.01%, Zr: 0.04%, Mg: 0.03 - 0.04%, Mn: 0.01 - 0.05%, Si: ≤0.14%, Ru: 0.03 - 0.06%, Sr: 0.12 - 0.14%, and the balance is nickel and unavoidable impurities.

[0014] An embodiment of the present invention also provides an application of the nickel-based superalloy with a long high-temperature low-cycle fatigue life in an aeroengine.

[0015] An embodiment of the present invention also provides an application of the nickel-based superalloy with a long high-temperature low-cycle fatigue life in a gas turbine.

[0016] An embodiment of the present invention also provides a preparation method of a nickel-based superalloy with a long high-temperature low-cycle fatigue life, including the following steps:

[0017] (1) Vacuum smelt each raw material according to the ratio, and the smelting temperature is 1360 - 1520 °C;

[0018] (2) Adjust the casting temperature to 1280 - 1400 °C and cast into a billet;

[0019] (3) Heat-treat the billet prepared in step (2).

[0020] The advantages and technical effects brought by the preparation method of the nickel-based superalloy with long low-cycle fatigue life and good heat preservation in the embodiments of the present invention are as follows: 1. The method in the embodiments of the present invention can prepare a nickel-based superalloy with long high-temperature low-cycle fatigue life, which has excellent high-temperature performance, long low-cycle fatigue life, good casting performance, and no defects such as shrinkage cavities and hot cracks, meeting the requirements of the design and use of advanced aeroengines and gas turbines; 2. The method in the embodiments of the present invention is simple, reduces energy consumption, shortens the production cycle, improves production efficiency, and is suitable for popularization and application in industrial production.

[0021] In some embodiments, in the step (3), the temperature of the heat treatment is 740-1120°C, and the time of the heat treatment is 16-20 h. Detailed implementation manners

[0022] The embodiments of the present invention will be described in detail below. The embodiments are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0023] The nickel-based superalloy with long high-temperature low-cycle fatigue life in the embodiments of the present invention includes: C: 0.08-0.2%, Cr: 7-10%, Co: 8.0-11%, W: 6-11%, Al: 5.2-8.0%, Ta: 2-3.6%, Mo: 0.1-1.5%, Hf: 0.6-1.8%, Ti: 0.8-2.5%, B: 0.005-0.03%, Zr: 0.001-0.08%, Mg: 0.005-0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.005-0.06%, Sr: ≤0.15%, and the balance is nickel and inevitable impurities, calculated by mass percentage.

[0024] The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to the embodiments of the present invention adds elements W, Mo, and Co. Solution strengthening can improve the high-temperature strength of the alloy. In addition, by adding three γ'-phase forming elements, Al, Ti, and Ta, the alloy has nanoscale γ'-phases stably existing at 900-950°C, which has a precipitation strengthening effect. By reasonably matching grain boundary strengthening elements C, B, Zr, and Sr, the high-temperature performance and fatigue life of the alloy are significantly improved; the added element Ru is an element with a weak segregation tendency, which can effectively inhibit the precipitation of the TCP phase and is beneficial to interact with other elements to improve the mechanical properties of the alloy; the added element Sr can form dispersed intermetallic compounds during smelting, which are pinned at the grain boundaries, hinder dislocation movement, and improve the high-temperature performance and fatigue performance of the alloy; the alloy according to the embodiments of the present invention has a tensile strength of up to 1108 MPa, a yield strength of up to 845 MPa, an elongation after fracture of up to 14.7% at 950°C, a low-cycle fatigue life of up to 4900 times, no forging shrinkage holes are generated, and it has good processing performance, which can meet the requirements of the design and use of advanced aeroengines and gas turbines.

[0025] The functions of Ru and Sr in the nickel-based superalloy according to the embodiments of the present invention are as follows:

[0026] Ru is a γ-phase stabilizing element, which stabilizes the γ in the γ+γ' eutectic and can effectively inhibit the precipitation of large primary M6C carbides generated during the slow cooling of alloy solidification and secondary M6C carbides during alloy heat treatment, which is beneficial to stabilizing the alloy structure. At the same time, Ru is an element with a very weak segregation tendency and mainly enters the γ-phase. Cooperating with other strengthening elements, the alloy can obtain stable high-temperature mechanical properties. However, as the Ru content increases, the eutectic content of the as-cast structure of the alloy will decrease, and the interdendritic distance will decrease, resulting in more difficult homogenization solution treatment. Therefore, in the embodiments of the present invention, the content of element Ru is controlled within the range of 0.01-0.06%.

[0027] The Sr element is an alloy element with better high-temperature performance, which can improve the alloy structure, prevent crack propagation, significantly improve the fatigue damage resistance of the alloy material, and can form dispersed intermetallic compounds during smelting, segregate at the grain boundaries, hinder dislocation movement, and improve the high-temperature strength of the alloy; in addition, the Sr element can also purify the alloy solution, reduce defects such as microshrinkage and hot cracks, and improve the processing performance of the alloy. However, if the Sr content is too high, brittle phases will appear at the grain boundaries, reducing the strength and elongation of the as-cast alloy. Therefore, in the embodiments of the present invention, the content of element Sr is controlled ≤0.15%.

[0028] In some embodiments, preferably, Ta, W, and Al satisfy the relational expression 1.22 ≤ Ta - 0.45W / Al ≤ 2.14, where Ta, W, and Al are the values obtained by removing the percentage sign from the mass percentage contents of elements Ta, W, and Al in the nickel-based superalloy, that is, Ta is 2 to 3.6, W is 6 to 11, and Al is 5.2 to 8.0.

[0029] In the embodiments of the present invention, defining that Ta, W, and Al satisfy the relational expression 1.22 ≤ Ta - 0.45W / Al ≤ 2.14 can give full play to the synergistic effect among Ta, W, and Al, which is beneficial to improving the high-temperature strength and fatigue life of the alloy.

[0030] In some embodiments, preferably, Mo, Ru, and C satisfy the relational expression 0.5 < 2Mo - 3Ru / C < 2.75, where Mo, Ru, and C are the values obtained by removing the percentage sign from the mass percentage contents of elements Mo, Ru, and C in the nickel-based superalloy, that is, Mo is 0.1 to 1.5, Ru is 0.005 to 0.06, and C is 0.08 to 0.2.

[0031] In the embodiments of the present invention, defining that Mo, Ru, and C satisfy the relational expression 0.5 < 2Mo - 3Ru / C < 2.75 can give full play to the synergistic effect among Mo, Ru, and C, making the alloy have excellent high-temperature strength, fatigue life, and thermal stability.

[0032] In some embodiments, preferably, Hf, Mg, Sr, and Ru satisfy the relational expression 0.08 < (Sr + Ru) / (Hf + Mg) < 0.23, where Hf, Mg, Sr, and Ru are the values obtained by removing the percentage sign from the mass percentage contents of elements Hf, Mg, Sr, and Ru in the nickel-based superalloy, that is, Hf is 0.6 to 1.8, Mg is 0.005 to 0.06, Sr ≤ 0.15, and Ru is 0.005 to 0.06.

[0033] In the embodiments of the present invention, defining that Hf, Mg, Sr, and Ru satisfy the relational expression 0.08 < (Sr + Ru) / (Hf + Mg) < 0.23 can give full play to the synergistic effect among Hf, Mg, Sr, and Ru, making the alloy have excellent high-temperature strength, fracture toughness, and machining properties.

[0034] In some embodiments, preferably, the nickel-based superalloy with a long high-temperature low-cycle fatigue life comprises: C: 0.08 - 0.2%, Cr: 7 - 9.7%, Co: 8.0 - 11%, W: 6.4 - 10.8%, Al: 5.2 - 8.0%, Ta: 2.0 - 3.5%, Mo: 0.5 - 1.5%, Hf: 0.6 - 1.8%, Ti: 0.8 - 2.5%, B: 0.005 - 0.03%, Zr: 0.002 - 0.08%, Mg: 0.005 - 0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.01 - 0.06%, Sr: 0.02 - 0.15%, with the balance being nickel and unavoidable impurities. Further preferably: C: 0.12 - 0.18%, Cr: 8.5 - 9.5%, Co: 10.5 - 10.7%, W: 8.6 - 10.5%, Al: 5.8 - 6.0%, Ta: 2.2 - 2.7%, Mo: 1 - 1.2%, Hf: 1.2 - 1.3%, Ti: 1.6 - 2%, B: 0.005 - 0.01%, Zr: 0.04%, Mg: 0.03 - 0.04%, Mn: 0.01 - 0.05%, Si: ≤0.14%, Ru: 0.03 - 0.06%, Sr: 0.12 - 0.14%, with the balance being nickel and unavoidable impurities, by mass percentage.

[0035] The embodiments of the present invention also provide an application of the nickel-based superalloy with a long high-temperature low-cycle fatigue life in an aeroengine. The nickel-based superalloy with a long high-temperature low-cycle fatigue life in the embodiments of the present invention meets the requirements of the design and use of advanced aeroengines and can be applied to the hot-end components of advanced aeroengines.

[0036] The embodiments of the present invention also provide an application of the nickel-based superalloy with a long high-temperature low-cycle fatigue life in a gas turbine. The nickel-based superalloy with a long high-temperature low-cycle fatigue life in the embodiments of the present invention meets the requirements of the design and use of gas turbines and can be applied to the hot-end components of gas turbines.

[0037] The embodiments of the present invention also provide a preparation method of a nickel-based superalloy with a long high-temperature low-cycle fatigue life, comprising the following steps:

[0038] (1) Vacuum smelt each raw material according to the ratio, and the smelting temperature is 1360 - 1520 °C;

[0039] (2) Adjust the casting temperature to 1280 - 1400 °C and cast it into a billet;

[0040] (3) Heat-treat the billet prepared in step (2).

[0041] The nickel-based superalloy with long thermal insulation low-cycle fatigue life prepared by the preparation method of the nickel-based superalloy of the embodiment of the present invention has excellent high-temperature performance and anti-fatigue performance, long low-cycle fatigue life, good casting performance, no shrinkage cavity, hot crack and other defects, meeting the requirements of the design and use of advanced aeroengines and gas turbines; the method of the embodiment of the present invention is simple, reduces energy consumption, shortens the production cycle, improves production efficiency, and is suitable for the popularization and application of industrial production.

[0042] In some embodiments, preferably, in step (3), the temperature of the heat treatment is 740-1120 °C, and the time of the heat treatment is 16-20 h.

[0043] The technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0044] Example 1

[0045] (1) Vacuum smelt each element according to the ratio, and the smelting temperature is 1520 °C;

[0046] (2) Adjust the casting temperature to 1380 °C and cast it into a blank;

[0047] (3) Treat the casting blank prepared in step (2) at 1120 °C for 18 hours.

[0048] The alloy composition obtained in Example 1 is shown in Table 1, and the performance is shown in Table 2.

[0049] The preparation methods of Examples 2-4 are the same as those of Example 1, except that the alloy compositions are different. The alloy compositions obtained in Examples 2-4 are shown in Table 1, and the performance is shown in Table 2.

[0050] Example 5

[0051] The preparation method of Example 5 is the same as that of Example 1, except that the alloy composition is different, wherein Ta-0.45W / Al = 2.58, 2Mo-3Ru / C = 2.85, (Sr+Ru) / (Hf+Mg) = 0.08. The alloy composition obtained in Example 5 is shown in Table 1, and the performance is shown in Table 2.

[0052] Example 6

[0053] The preparation method of Example 6 is the same as that of Example 1, except that the alloy composition is different, wherein Ta-0.45W / Al = 1.48, 2Mo-3Ru / C = 0.13, (Sr+Ru) / (Hf+Mg) = 0.06. The alloy composition obtained in Example 6 is shown in Table 1, and the performance is shown in Table 2.

[0054] Example 7

[0055] Example 7 has the same preparation method as Example 1, except that the alloy compositions are different. Among them, Ta - 0.45W / Al = 2.36, 2Mo - 3Ru / C = 2.1, (Sr + Ru) / (Hf + Mg) = 0.05. The alloy composition obtained in Example 7 is shown in Table 1, and the performance is shown in Table 2.

[0056] Example 8

[0057] Example 8 has the same preparation method as Example 1, except that the alloy compositions are different. Among them, Ta - 0.45W / Al = 2.59, 2Mo - 3Ru / C = 0.4, (Sr + Ru) / (Hf + Mg) = 0.11. The alloy composition obtained in Example 8 is shown in Table 1, and the performance is shown in Table 2.

[0058] Example 9

[0059] Example 9 has the same preparation method as Example 1, except that the alloy compositions are different. Among them, Ta - 0.45W / Al = 2.03, 2Mo - 3Ru / C = 2.31, (Sr + Ru) / (Hf + Mg) = 0.04. The alloy composition obtained in Example 9 is shown in Table 1, and the performance is shown in Table 2.

[0060] Example 10

[0061] Example 10 has the same preparation method as Example 1, except that the alloy compositions are different. Among them, Ta - 0.45W / Al = 1.97, 2Mo - 3Ru / C = 0.25, (Sr + Ru) / (Hf + Mg) = 0.22. The alloy composition obtained in Example 10 is shown in Table 1, and the performance is shown in Table 2.

[0062] Example 11

[0063] Example 11 has the same preparation method as Example 1, except that the alloy compositions are different. Among them, Ta - 0.45W / Al = 2.53, 2Mo - 3Ru / C = 0.85, (Sr + Ru) / (Hf + Mg) = 0.12. The alloy composition obtained in Example 11 is shown in Table 1, and the performance is shown in Table 2.

[0064] Comparative Example 1

[0065] Comparative Example 1 has the same preparation method as Example 1, except that the alloy compositions are different and do not contain Ru and Sr elements. The alloy composition obtained in Comparative Example 1 is shown in Table 1, and the performance is shown in Table 2.

[0066] Comparative Example 2

[0067] Comparative Example 2 has the same preparation method as Example 1, except that the alloy compositions are different and do not contain Sr element. The alloy composition obtained in Comparative Example 2 is shown in Table 1, and the performance is shown in Table 2.

[0068] Comparative Example 3

[0069] The preparation method of Comparative Example 3 was the same as that of Example 1, except that the alloy composition was different and it did not contain the Ru element. The alloy composition obtained in Comparative Example 3 is shown in Table 1, and the performance is shown in Table 2.

[0070] Comparative Example 4

[0071] The preparation method of Comparative Example 4 was the same as that of Example 1, except that the alloy composition was different. The Ru content was 0.12% and the Sr content was 0.35%. The alloy composition obtained in Comparative Example 4 is shown in Table 1, and the performance is shown in Table 2.

[0072] Table 1

[0073]

[0074] Table 2

[0075]

[0076]

[0077] Note: High-temperature low-cycle fatigue life: The specimen was heated to 950 °C, and a high-temperature low-cycle fatigue test was carried out on a fatigue testing machine. Axial tension-compression full-reverse total strain control was adopted, and the strain rate was 4×10 -3 s -1 , the strain ratio was -1, and the maximum stress drop of 20% was used as the failure judgment basis. The number of cycles was recorded, which was the fatigue life of the specimen;

[0078] Shrinkage cavity observation: Observation was carried out under a microscope by the dissection method.

[0079] It can be seen from the data in Table 1 and Table 2 that the nickel-based superalloy prepared by controlling the content of each element in the examples of the present invention has a high-temperature tensile strength exceeding 920 MPa at 950 °C, a yield strength higher than 730 MPa, an elongation after fracture greater than 12%, a fatigue life exceeding 3800 times, no casting shrinkage cavity generated, good workability, and can meet the requirements of the design and use of aeroengines and gas turbines. When the formula 1.22 ≤ Ta - 0.45W / Al ≤ 2.14, 0.5 < 2Mo - 3Ru / C < 2.75 and 0.08 < (Sr + Ru) / (Hf + Mg) < 0.23 are satisfied, such as in Examples 1 to 4, the prepared nickel-based superalloy has better performance.

[0080] In Comparative Example 1, the Ru and Sr elements were not added to the alloy, which could not prevent crack propagation, refine grains, and had a weak grain boundary strengthening effect, resulting in a low high-temperature strength, short fatigue life of the prepared nickel-based superalloy, and the generation of casting shrinkage cavities, and could not meet the use requirements.

[0081] In Comparative Example 2, element Sr was not added. Element Sr can hinder dislocation movement and crack propagation and strengthen grain boundaries, resulting in a decrease in the high-temperature tensile strength of the alloy prepared in Comparative Example 2, and the number of cycles is only 3500 times.

[0082] In Comparative Example 3, element Ru was not added. Element Ru can stabilize the structure and inhibit the precipitation of harmful phases, resulting in a high-temperature tensile strength of only 899 MPa and an elongation of only 11.6% for the alloy prepared in Comparative Example 3.

[0083] In Comparative Example 4, the addition amount of Ru was 0.12% and the addition amount of Sr was 0.35%. Both Ru and Sr can play a role in strengthening the alloy, and the strengthening effect is more significant when they are added in combination. However, element Ru is a refractory element, and too much content will generate refractory phases during melting, affecting the homogenization of the alloy. Moreover, too much Sr is likely to generate brittle phases at grain boundaries, seriously reducing the strength and plasticity of the alloy. In Comparative Example 4, the contents of Ru and Sr are relatively high, so the high-temperature tensile strength of the prepared alloy is only 890 MPa, the elongation after fracture drops to 11.3%, the fatigue life is only 3400 times, and casting shrinkage cavities are generated.

[0084] In the present invention, terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0085] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A nickel-based superalloy with a long high-temperature low-cycle fatigue life, characterized in that, Comprising: C: 0.08 - 0.2%, Cr: 7 - 10%, Co: 8.0 - 11%, W: 6 - 11%, Al: 5.2 - 8.0%, Ta: 2 - 3.6%, Mo: 0.1 - 1.5%, Hf: 0.6 - 1.8%, Ti: 0.8 - 2.5%, B: 0.005 - 0.03%, Zr: 0.001 - 0.08%, Mg: 0.005 - 0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.005 - 0.06%, Sr: ≤0.15%, with the balance being nickel and unavoidable impurities, by mass percentage; The Mo, Ru, and C satisfy the relationship 0.5 < 2Mo - 3Ru / C < 2.75, where Mo, Ru, and C are the values after removing the percentage signs of the mass percentages of elements Mo, Ru, and C in the nickel - based superalloy.

2. The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to claim 1, characterized in that, The Ta, W, and Al satisfy the relationship 1.22 ≤ Ta - 0.45W / Al ≤ 2.14, where Ta, W, and Al are the values after removing the percentage signs of the mass percentages of elements Ta, W, and Al in the nickel - based superalloy.

3. The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to claim 1, characterized in that, The Hf, Mg, Sr, and Ru satisfy the relationship 0.08 < (Sr + Ru) / (Hf + Mg) < 0.23, where Hf, Mg, Sr, and Ru are the values after removing the percentage signs of the mass percentages of elements Hf, Mg, Sr, and Ru in the nickel - based superalloy.

4. The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to claim 1, characterized in that, Comprising: C: 0.08 - 0.2%, Cr: 7 - 9.7%, Co: 8.0 - 11%, W: 6.4 - 10.8%, Al: 5.2 - 8.0%, Ta: 2.0 - 3.5%, Mo: 0.5 - 1.5%, Hf: 0.6 - 1.8%, Ti: 0.8 - 2.5%, B: 0.005 - 0.03%, Zr: 0.002 - 0.08%, Mg: 0.005 - 0.06%, Mn: ≤0.06%, Si: ≤0.15%, Ru: 0.01 - 0.06%, Sr: 0.02 - 0.15%, with the balance being nickel and unavoidable impurities.

5. The nickel-based superalloy with a long high-temperature low-cycle fatigue life according to claim 1, characterized in that, Comprising: C: 0.12 - 0.18%, Cr: 8.5 - 9.5%, Co: 10.5 - 10.7%, W: 8.6 - 10.5%, Al: 5.8 - 6.0%, Ta: 2.2 - 2.7%, Mo: 1 - 1.2%, Hf: 1.2 - 1.3%, Ti: 1.6 - 2%, B: 0.005 - 0.01%, Zr: 0.04%, Mg: 0.03 - 0.04%, Mn: 0.01 - 0.05%, Si: ≤0.14%, Ru: 0.03 - 0.06%, Sr: 0.12 - 0.14%, with the balance being nickel and unavoidable impurities.

6. Application of the nickel - based superalloy with long high - temperature low - cycle fatigue life according to any one of claims 1 - 5 in an aero - engine.

7. Application of the nickel - based superalloy with long high - temperature low - cycle fatigue life according to any one of claims 1 - 5 in a gas turbine.

8. A method for preparing a nickel-based superalloy with a long high-temperature low-cycle fatigue life according to any one of claims 1 to 5, characterized in that, Comprising the following steps: (1) Vacuum smelt each raw material according to the ratio, and the smelting temperature is 1360 - 1520 °C; (2) Adjust the casting temperature to 1280 - 1400 °C and cast it into a billet; (3) Heat-treat the billet prepared in step (2).

9. The preparation method of the nickel-based superalloy with a long high-temperature low-cycle fatigue life according to claim 8, characterized in that, In the said step (3), the temperature of the heat treatment is 740 - 1120 °C, and the time of the heat treatment is 16 - 20 h.

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