A bend-crack-free nickel-based superalloy, its preparation method and application

Abstract

The present invention relates to the field of alloys, and particularly to a bend-crack-free nickel-based superalloy, its preparation method and application. A nickel-based superalloy provided by the present invention comprises C: 0.05 - 0.09%, Cr: 18.00 - 21.00%, Co: 8.50 - 11.00%, Mo: 7.50 - 9.00%, Al: 1.40 - 1.60%, Ti: 1.95 - 2.15%, Nb: 0.01 - 0.2%, W: 0.01 - 0.2%, Zr: 0 - 0.1% and B: 0.001 - 0.009%, with the balance being nickel and inevitable impurities, by mass percentage. Among them, C, Cr and Ti satisfy the relational expression 1.52 < (9.5C + 0.15Cr) / Ti < 1.97. By controlling the ratio of the three elements, its high-temperature creep and high-temperature tensile properties meet the usage requirements, and no visible cracks appear after bending.

Description

Technical Field

[0001] The present invention relates to the field of alloys, and particularly to a bend-crack-free nickel-based superalloy, a preparation method thereof, and an application thereof. Background Art

[0002] Nickel-based superalloys play a particularly important role in the entire field of superalloys. They are widely used to manufacture the hottest components of aero jet engines and various industrial gas turbines. If the 150 MPa - 100 h creep strength is used as the standard, currently the highest temperature that nickel alloys can withstand > 1100 °C, while iron-based alloys < 850 °C, that is, nickel-based alloys are correspondingly about 150 °C to 250 °C higher. Therefore, nickel alloys are called the heart of the engine.

[0003] Currently, on advanced engines, nickel alloys already account for half of the total weight. Not only turbine blades and combustion chambers, but also turbine disks and even the last few stages of compressor blades have started to use nickel alloys. Compared with iron alloys, the advantages of nickel alloys are: higher working temperature, stable microstructure, fewer harmful phases, and strong oxidation and corrosion resistance. Compared with cobalt alloys, nickel alloys can work at higher temperatures and stresses, especially in the case of moving blades. Therefore, the research on nickel-based superalloys is of great significance for the development of China's aerospace industry. Summary of the Invention

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

[0005] The combustion chamber is a key heat-bearing component in an aeroengine. The combustion chamber is the area with the highest temperature among the engine components. When the gas temperature in the combustion chamber reaches 1500 °C - 1800 °C, the temperature of the chamber wall alloy can reach 800 °C - 900 °C or more, and locally can reach 1100 °C. Therefore, the mechanical stress on the combustion chamber is small, but the thermal stress is large. The main requirements for the material are: high-temperature oxidation and gas corrosion resistance; sufficient strength; good thermal and cold fatigue performance; good process plasticity (creep and bending performance) and welding performance; and long-term microstructure stability of the alloy at the working temperature. With the development of technology, traditional alloys and corresponding alternative alloys can no longer meet the needs of technological progress. Therefore, it is necessary to develop new high-temperature alloy materials.

[0006] The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, an embodiment of the present invention provides a bend crack-free nickel-based superalloy and a preparation method thereof. The nickel-based superalloy limits the relational expression that C, Cr, and Ti need to satisfy as 1.52 < (9.5C + 0.15Cr) / Ti < 1.97. By controlling the dosage ratio among the three elements, the synergistic effect among the three elements can be exerted, enabling the alloy material to reach the optimal comprehensive performance level, so that its high-temperature creep and high-temperature tensile properties meet the use requirements, and no visible cracks appear after bending.

[0007] A bend crack-free nickel-based superalloy according to an embodiment of the present invention includes C: 0.05 - 0.09%, Cr: 18.00 - 21.00%, Co: 8.50 - 11.00%, Mo: 7.50 - 9.00%, Al: 1.40 - 1.60%, Ti: 1.95 - 2.15%, Nb: 0.01 - 0.2%, W: 0.01 - 0.2%, Zr: 0 - 0.1%, and B: 0.001 - 0.009%, with the balance being nickel and unavoidable impurities, by mass percentage. Among them, the mass percentages of C, Cr, and Ti satisfy the relational expression 1.52 < (9.5C + 0.15Cr) / Ti < 1.97.

[0008] The advantages and technical effects of the bend crack-free nickel-based superalloy according to an embodiment of the present invention are as follows: 1. In the embodiment of the present invention, the nickel-based superalloy is prepared by adjusting the content of each component. Ni forms the matrix γ phase and forms Ni 3 (Ti, Al)γ phase intermetallic compound, which is the main strengthening phase of the superalloy, and is beneficial to the high-temperature strength and high-temperature hardness of the alloy; 2. In the embodiment of the present invention, the Nb element is added. Nb is a strong carbide-forming element, which is beneficial to the high-temperature strength of the material and makes an obvious contribution to wear resistance. At the same time, Nb combines with C, which can prevent grain growth during high-temperature solution, and has the characteristics of refining grains, improving the plasticity and hot workability of the material; 3. In the embodiment of the present invention, it is limited that C, Cr, and Ti satisfy 1.52 < (9.5C + 0.15Cr) / Ti < 1.97, which can maximize the synergistic effect among C, Cr, and Ti. The alloy not only has excellent high-temperature durability, and its creep life can reach more than 350 h under the conditions of 89 MPa and 927 °C, and its high-temperature tensile yield strength can reach 330 MPa. The alloy reaches the optimal comprehensive performance level and can meet the requirements of the design and use of advanced aeroengines and gas turbines.

[0009] In some embodiments, the nickel-based superalloy comprises: C: 0.05 - 0.07%, Cr: 18.06 - 20.89%, Co: 9.79 - 10.54%, Mo: 7.94 - 8.91%, Al: 1.45 - 1.58%, Ti: 1.96 - 2.11%, Nb: 0.06 - 0.18%, W: 0.04 - 0.16%, Zr: 0.07 - 0.98%, and B: 0.005 - 0.007%, with the balance being nickel and unavoidable impurities, by mass percentage.

[0010] In some embodiments, the mass percentages of C, Cr, and Ti satisfy the relationship 1.546 < (9.5C + 0.15Cr) / Ti < 1.938.

[0011] In some embodiments, the nickel-based superalloy comprises: C: 0.05 - 0.07%, Cr: 19.00 - 20.89%, Co: 10.03 - 10.21%, Mo: 8.58 - 8.91%, Al: 1.45 - 1.53%, Ti: 1.96 - 1.98%, Nb: 0.09 - 0.18%, W: 0.05 - 0.06%, Zr: 0.072 - 0.084%, and B: 0.006 - 0.007%, with the balance being nickel and unavoidable impurities, by mass percentage.

[0012] In some embodiments, the mass percentages of C, Cr, and Ti satisfy the relationship 1.745 < (9.5C + 0.15Cr) / Ti < 1.938.

[0013] The embodiments of the present invention also provide an application of the bend crack-free nickel-based superalloy in an aeroengine or a gas turbine.

[0014] The embodiments of the present invention also provide an application of the bend crack-free nickel-based superalloy in a rocket engine.

[0015] The embodiments of the present invention also provide a preparation method of the bend crack-free nickel-based superalloy, comprising the following steps:

[0016] (1) Conduct vacuum induction furnace smelting according to the above raw material ratio, with the smelting temperature being 1550 - 1650 °C. After melting is complete, sample and analyze the composition, and then adjust the composition.

[0017] (2) Adjust the pouring temperature to 1510 - 1540 °C and pour into a billet.

[0018] (3) Clean the cast billet and then conduct diffusion annealing heat treatment.

[0019] The advantages and technical effects brought by a preparation method of a bend - crack - free nickel - based superalloy according to an embodiment of the present invention are as follows: 1. In the embodiment of the present invention, the nickel - based superalloy prepared by this method has excellent creep life, high - temperature tensile properties and bending properties, and can meet the requirements of the design and use of advanced aero - engines and gas turbines; 2. In the embodiment of the present invention, the composition is adjusted after melting to ensure the precise ratio between components, so that the excellent properties of the alloy can be fully exerted, which is suitable for popularization and application in industry.

[0020] In some embodiments, the temperature of refining is 1550 - 1650 °C and the time is 0.5 - 1 hour.

[0021] In some embodiments, the diffusion annealing heat treatment is to heat the ingot blank to 1180 - 1220 °C, keep it warm for 48 - 60 h, and air - cool it to room temperature. Specific embodiments

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

[0023] A bend - crack - free nickel - based superalloy according to an embodiment of the present invention includes C: 0.05 - 0.09%, Cr: 18.00 - 21.00%, Co: 8.50 - 11.00%, Mo: 7.50 - 9.00%, Al: 1.40 - 1.60%, Ti: 1.95 - 2.15%, Nb: 0.01 - 0.2%, W: 0.01 - 0.2%, Zr: 0 - 0.1% and B: 0.001 - 0.009%, and the balance is nickel and inevitable impurities, by mass percentage. Among them, the mass percentages of C, Cr and Ti satisfy the relational expression 1.52 < (9.5C + 0.15Cr) / Ti < 1.97.

[0024] A bend - crack - free nickel - based superalloy according to an embodiment of the present invention prepares a nickel - based superalloy by adjusting the content of each component. Ni forms the matrix γ - phase and forms Ni with Al, Ti, etc. 3(Ti, Al) γ-phase intermetallic compound is the main strengthening phase of this superalloy, which is beneficial to the high-temperature strength and hardness of the alloy; Nb element is added. Nb is a strong carbide-forming element, which is beneficial to the high-temperature strength of the material and makes an obvious contribution to wear resistance. At the same time, Nb combines with C to prevent grain growth during high-temperature solution, and has the characteristics of refining grains, improving the plasticity and hot workability of the material; it is specified that C, Cr, and Ti satisfy 1.52 < (9.5C + 0.15Cr) / Ti < 1.97, which can maximize the synergistic effect among C, Cr, and Ti. The alloy not only has excellent high-temperature durability, but also has a creep rupture life of more than 350 h under the conditions of 89 MPa and 927 °C, and the high-temperature tensile yield strength can reach 330 MPa. The alloy reaches the best comprehensive performance level and can meet the requirements of the design and use of advanced aeroengines and gas turbines.

[0025] The functions of C, Cr, and Ti in the bend-crack-free nickel-based superalloy in the embodiments of the present invention are as follows:

[0026] C in the nickel-based superalloy mainly serves as a grain boundary strengthening element, and improves the mechanical properties by forming carbides. When granular discontinuous carbides precipitate at the grain boundary, it can prevent intergranular sliding and crack propagation, improve the creep rupture life, and improve the creep plasticity and toughness. Specifically, it inhibits the growth of austenite grains during heating by forming MC-type carbides at the end of solidification, and forms M 23 C 6 and other types of carbides at the grain boundary during heat treatment, playing a role in strengthening the grain boundary, which can delay the initiation, propagation, and coalescence of creep cavities, thereby improving the high-temperature creep rupture life of the alloy. When the C content is less than 0.04%, it is not enough to form a sufficient number of MC and M 23 C 6 . When the C content is too high, the formed MC has a large size, often becoming a fatigue crack source or propagation channel, and will excessively consume Mo, Cr, Ti, and Nb in the alloy. On the one hand, it not only reduces the solid solution strengthening effect of Mo and Cr, but on the other hand, the Ti and Nb used to form Ni 3 (Al, Ti) and Ni 3 (Al, Ti, Nb) composite strengthening phases will be reduced, which will have an adverse impact on the high-temperature creep resistance and creep rupture performance of the alloy. Therefore, the C content should be controlled not to exceed 0.1%.

[0027] The main function of Cr is to improve the oxidation resistance of the alloy and has a certain solid solution strengthening effect. In the γ′-strengthened nickel-based high-temperature alloy, about 1 / 10 of the Cr content is usually added to enter the γ′ phase, a small amount forms carbides, and the rest dissolves in the γ′ solid solution. Cr in the γ matrix of the high-temperature alloy causes lattice distortion and produces elastic stress field strengthening, thereby increasing the strength of the γ solid solution and achieving solid solution strengthening. When the Cr content is too high, it is easy to form a topological close-packed phase, which reduces the long-term organizational performance stability of the alloy. Therefore, its content generally does not exceed 25%. In the embodiment of the present invention, considering both the oxidation resistance and the stability of the long-term organizational performance, the Cr content is controlled at 18-21%.

[0028] Ti is a forming element of the strengthening phase γ′ in age-strengthening nickel-based alloys. It is generally believed that with the increase of Ti content, the amount of γ′ phase increases, achieving the improvement of high-temperature creep and endurance performance and room temperature strength, but too much γ′ phase will deteriorate welding performance and damage processing performance. In addition, Ti and Nb will also combine with C to form MC-type carbides, which will hinder grain boundary growth and grain boundary sliding at high temperatures and play a role in improving high-temperature mechanical properties. However, too much Ti and Nb will form large-particle MC-type carbides, which are not good for the mechanical properties of the alloy.

[0029] In some embodiments, preferably, the nickel-based high-temperature alloy includes: C: 0.05-0.07%, Cr: 18.06-20.89%, Co: 9.79-10.54%, Mo: 7.94-8.91%, Al: 1.45-1.58%, Ti: 1.96-2.11%, Nb: 0.06-0.18%, W: 0.04-0.16%, Zr: 0.07-0.98% and B: 0.005-0.007%, and the balance is nickel and unavoidable impurities, calculated by mass percentage. Further preferably, the mass percentage of C, Cr and Ti satisfies the relationship 1.546<(9.5C+0.15Cr) / Ti<1.938.

[0030] In some embodiments, preferably, the nickel-based high-temperature alloy includes: C: 0.05-0.07%, Cr: 19.00-20.89%, Co: 10.03-10.21%, Mo: 8.58-8.91%, Al: 1.45-1.53%, Ti: 1.96-1.98%, Nb: 0.09-0.18%, W: 0.05-0.06%, Zr: 0.072-0.084% and B: 0.006-0.007%, and the balance is nickel and unavoidable impurities, calculated by mass percentage. In some embodiments, the mass percentage of C, Cr and Ti satisfies the relationship 1.745<(9.5C+0.15Cr) / Ti<1.938.

[0031] In the embodiments of the present invention, the content of components in the nickel-based superalloy and the relational expressions satisfied by the mass percentages of C, Cr, and Ti are further optimized, so that the creep life of the nickel-based superalloy can reach more than 400 h under the conditions of 89 MPa and 927 °C, the high-temperature tensile yield strength reaches more than 350 MPa, and the high-temperature tensile strength reaches more than 460 MPa; at the same time, the elongation rate of the nickel-based superalloy can still be maintained at a relatively high level. Thus, it can be seen that the comprehensive performance of the nickel-based alloy reaches a relatively high level at this time.

[0032] The embodiments of the present invention also provide an application of the bend-crack-free nickel-based superalloy in an aeroengine or a gas turbine. The nickel-based superalloy in the embodiments of the present invention meets the requirements for the design and use of advanced aeroengines or gas turbines and can be applied to precision equipment of advanced aeroengines or gas turbines.

[0033] The embodiments of the present invention also provide an application of the bend-crack-free nickel-based superalloy in a rocket engine. The nickel-based superalloy in the embodiments of the present invention has excellent comprehensive performance and can be applied to rocket engines.

[0034] The embodiments of the present invention also provide a preparation method of the bend-crack-free nickel-based superalloy, including the following steps:

[0035] (1) Conduct vacuum induction furnace smelting according to the above raw material ratio. After melting is complete, sample and analyze the composition, and then adjust the composition.

[0036] (2) Adjust the pouring temperature to 1510 - 1540 °C and pour it into a billet.

[0037] (3) After cleaning the cast billet, perform diffusion annealing heat treatment.

[0038] The preparation method of the bend-crack-free nickel-based superalloy in the embodiments of the present invention can produce a nickel-based superalloy with excellent creep life, high-temperature tensile performance, and bending performance, which can meet the requirements for the design and use of advanced aeroengines and gas turbines; moreover, in the preparation method of the present invention, the composition is adjusted after melting is complete to ensure the precise ratio between components, so that the excellent performance of the alloy can be fully exerted, and it is suitable for popularization and application in industry.

[0039] In some embodiments, preferably, the smelting temperature is 1550 - 1650 °C and the time is 0.5 - 1 hour. Further preferably, the diffusion annealing heat treatment is to heat the cast billet to 1180 - 1220 °C, hold for 48 - 60 h, and air-cool to room temperature.

[0040] In the embodiments of the present invention, the processes of refining and heat treatment are preferably adopted, which can reduce the defects in the internal metallographic structure of the alloy, achieve the purpose of degassing, dephosphorizing, desulfurizing, and blending various trace alloys, maximize the excellent properties of the alloy, and improve the mechanical properties of the metal.

[0041] The present invention will be described in detail below with reference to the embodiments.

[0042] Example 1

[0043] (1) Weigh the selected raw materials with qualified purity according to the designed ratio and conduct smelting in a vacuum induction furnace. The smelting temperature is 1550 °C. After the melt is clarified, sample and analyze the composition, and then adjust the composition. If a certain component is less, add the corresponding element for melting until the designed ratio is reached.

[0044] (2) Adjust the pouring temperature to 1510 °C and pour it into a billet.

[0045] (3) After cleaning the cast billet, conduct diffusion annealing heat treatment. First, heat the cast billet to 1200 °C, hold for 48 h, and then air-cool to room temperature.

[0046] The alloy composition obtained in Example 1 is shown in Table 1, and the performance is shown in Table 2.

[0047] Example 2

[0048] (1) Weigh the selected raw materials with qualified purity according to the designed ratio and conduct smelting in a vacuum induction furnace. The smelting temperature is 1600 °C. After the melt is clarified, sample and analyze the composition, and then adjust the composition to make the chemical composition of the nickel-based alloy meet the standard.

[0049] (2) Adjust the pouring temperature to 1540 °C and pour it into a billet.

[0050] (3) After cleaning the cast billet, conduct diffusion annealing heat treatment. First, heat the cast billet to 1180 °C, hold for 50 h, and then air-cool to room temperature.

[0051] The alloy composition obtained in Example 2 is shown in Table 1, and the performance is shown in Table 2.

[0052] Examples 3-8 have the same preparation method as Example 1, except for the different alloy compositions. The alloy compositions obtained in Examples 3-10 are shown in Table 1, and the performance is shown in Table 2.

[0053] Comparative Example 1

[0054] Comparative Example 1 has the same preparation method as Example 1, but the difference lies in the alloy composition, where the content of element C is 0.15%. The alloy composition obtained in Comparative Example 1 is shown in Table 1, and the performance is shown in Table 2.

[0055] Comparative Example 2

[0056] The preparation method of Comparative Example 2 is the same as that of Example 1, except that in the alloy composition, the content of element C is 0.03%. The alloy composition obtained in Comparative Example 2 is shown in Table 1, and the performance is shown in Table 2.

[0057] Comparative Example 3

[0058] The preparation method of Comparative Example 3 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 2.25%. The alloy composition obtained in Comparative Example 3 is shown in Table 1, and the performance is shown in Table 2.

[0059] Comparative Example 4

[0060] The preparation method of Comparative Example 4 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 2.18% and the content of element Cr is 21.26%. The alloy composition obtained in Comparative Example 4 is shown in Table 1, and the performance is shown in Table 2.

[0061] Comparative Example 5

[0062] The preparation method of Comparative Example 5 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 1.88% and the content of element Cr is 16.85%. The alloy composition obtained in Comparative Example 5 is shown in Table 1, and the performance is shown in Table 2.

[0063] Comparative Example 6

[0064] The preparation method of Comparative Example 6 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 2.20% and the content of element Cr is 21.17%. The alloy composition obtained in Comparative Example 6 is shown in Table 1, and the performance is shown in Table 2.

[0065] Comparative Example 7

[0066] The preparation method of Comparative Example 7 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 2.30% and the content of element C is 0.04%. The alloy composition obtained in Comparative Example 7 is shown in Table 1, and the performance is shown in Table 2.

[0067] Comparative Example 8

[0068] The preparation method of Comparative Example 8 is the same as that of Example 1, except that in the alloy composition, the content of element Ti is 2.17% and the content of element C is 0.04%. The alloy composition obtained in Comparative Example 8 is shown in Table 1, and the performance is shown in Table 2.

[0069] Comparative Example 9

[0070] The preparation method of Comparative Example 9 is the same as that of Example 1, except that in the alloy composition, the mass percentages of elements C, Cr, and Ti satisfy (9.5C + 0.15Cr) / Ti = 1.478. The alloy composition obtained in Comparative Example 9 is shown in Table 1, and the performance is shown in Table 2.

[0071] Comparative Example 10

[0072] The preparation method of Comparative Example 10 is the same as that of Example 1, except that in the alloy composition, the mass percentage contents of elements C, Cr and Ti satisfy (9.5C + 0.15Cr) / Ti = 1.982. The alloy composition obtained in Comparative Example 10 is shown in Table 1, and the performance is shown in Table 2.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077]

[0078] Note: 1. τ is the creep life of the aged alloy under the conditions of 89 MPa and 927 °C, and δ is the creep elongation after fracture of the aged alloy under the conditions of 89 MPa and 927 °C;

[0079] 2. R p0.2 is the high-temperature tensile yield strength of the aged alloy at 927 °C, R m is the high-temperature tensile ultimate strength of the aged alloy at 927 °C, and A is the high-temperature tensile elongation after fracture of the aged alloy at 927 °C;

[0080] 3. The bending property is a process property, and the detection condition is 180° bending with a bending coefficient of 2.

[0081] From the data of each example and comparative example in Table 1 and Table 2, it can be seen that when the content of each element component in the alloy is within a certain range and satisfies 1.52 < (9.5C + 0.15Cr) / Ti < 1.97, the creep life of Examples 1 to 8 under the conditions of 89 MPa and 927 °C all exceed 350 h, the high-temperature tensile yield strength all exceeds 330 MPa, and the high-temperature tensile ultimate strength all exceeds 400 MPa; the creep elongation after fracture of the alloy under the conditions of 89 MPa and 927 °C all exceeds 25%, the high-temperature tensile elongation after fracture all exceeds 40%, and no cracks appear, all meeting the requirements for the design and use of advanced aero-engines and gas turbines.

[0082] In Comparative Examples 1-2, the content of C was changed. In Comparative Example 1, too much C element was added. Although the endurance performance was not affected, the high-temperature tensile yield strength and tensile strength were low, and cracks appeared during bending. In Comparative Example 2, the addition amount of C was insufficient. Although it had no effect on the endurance performance and there were no cracks during bending, the high-temperature tensile strength was low and the elongation was low. It can be seen that a small amount of C content will have an obvious impact on the performance of the alloy, especially it can well regulate its mechanical properties.

[0083] In Comparative Examples 3-6, the contents of Ti and Cr were adjusted. In Comparative Example 3, more Ti element was added. Although the endurance performance was good, the high-temperature tensile yield strength, tensile strength were low, and the elongation was low. In Comparative Example 4, more Ti and Cr elements were added, resulting in a serious decrease in the endurance life of the alloy. In Comparative Example 5, the addition amounts of Ti and Cr were reduced. Although the endurance performance was good, the high-temperature tensile yield strength and tensile strength were lower than those of the examples of the present application and were barely qualified. In Comparative Example 6, more Ti and Cr elements were added, the endurance life decreased seriously, the high-temperature tensile yield strength and tensile strength were close to the lower limit of qualification, and the elongation was on the low side. Adding Ti can improve high-temperature creep, endurance performance and high-temperature strength, but too much γ' phase will deteriorate the welding performance and damage the processing performance. When the Cr content is too high, it is easy to form a topologically close-packed phase, reducing the long-term tissue performance stability of the alloy.

[0084] In Comparative Examples 7 and 8, the contents of Ti and C were adjusted. By adding more Ti elements and reducing the amount of C element, it can be seen that the endurance performance is good, but the high-temperature tensile yield strength and tensile strength are both low, not meeting the standard performance requirements, and cracks appear during bending.

[0085] In Comparative Example 9, (9.5C + 0.15Cr) / Ti < 1.52, the high-temperature endurance performance is good, but the high-temperature tensile performance is unqualified. In Comparative Example 10, (9.5C + 0.15Cr) / Ti > 1.97, the endurance life decreased seriously compared with the examples of the present application, approaching or not meeting the lower limit required for the alloy, and the high-temperature tensile elongation is unqualified. It can be seen that the three elements of C, Cr, and Ti have a synergistic effect on the high-temperature mechanical properties of the alloy. In order to achieve the best comprehensive performance level, in the examples of the present invention, it is necessary to control that 1.52 < (9.5C + 0.15Cr) / Ti < 1.97 among the three elements.

[0086] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", 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.

Claims

1. A bend-free crack nickel-based superalloy, characterized in that, it comprises: C: 0.05 - 0.09%, Cr: 18.00 - 21.00%, Co: 8.50 - 11.00%, Mo: 7.00 - 9.00%, Al: 1.40 - 1.60%, Ti: 1.96 - 2.15%, Nb: 0.01 - 0.2%, W: 0.01 - 0.2%, Zr: 0 - 0.1% and B: 0.001 - 0.009%, with the balance being nickel and unavoidable impurities, by mass percentage. Among them, the mass percentages of C, Cr and Ti satisfy the relational expression 1.745 < (9.5C + 0.15Cr) / Ti < 1.

938. The creep life of the nickel-based superalloy under the conditions of 89 MPa and 927 °C exceeds 350 h, the creep elongation after fracture under the conditions of 89 MPa and 927 °C exceeds 25%, and the high-temperature tensile yield strength at 927 °C exceeds 330 MPa.

2. The bend-free crack nickel-based superalloy according to claim 1, characterized in that, the nickel-based superalloy comprises: C: 0.05 - 0.07%, Cr: 18.06 - 20.89%, Co: 9.79 - 10.54%, Mo: 7.94 - 8.91%, Al: 1.45 - 1.58%, Ti: 1.96 - 2.11%, Nb: 0.06 - 0.18%, W: 0.04 - 0.16%, Zr: 0.07 - 0.98% and B: 0.005 - 0.007%, with the balance being nickel and unavoidable impurities, by mass percentage.

3. The bend-free crack nickel-based superalloy according to claim 2, characterized in that, the nickel-based superalloy comprises: C: 0.05 - 0.07%, Cr: 19.00 - 20.89%, Co: 10.03 - 10.21%, Mo: 8.58 - 8.91%, Al: 1.45 - 1.53%, Ti: 1.96 - 1.98%, Nb: 0.09 - 0.18%, W: 0.05 - 0.06%, Zr: 0.072 - 0.084% and B: 0.006 - 0.007%, with the balance being nickel and unavoidable impurities, by mass percentage.

4. Application of the bend-free crack nickel-based superalloy according to any one of claims 1 to 3 in an aeroengine or a gas turbine.

5. Application of the bend-free crack nickel-based superalloy according to any one of claims 1 to 3 in a rocket engine.

6. A preparation method of the bend-free crack nickel-based superalloy according to any one of claims 1 to 3, characterized in that, it comprises the following steps: (1) Conduct vacuum induction furnace smelting according to the raw material ratio, sample and analyze the composition after melting to completion, and then adjust the composition; (2) Adjust the pouring temperature to 1510 - 1540 °C and pour into a billet; (3) After cleaning the cast billet, perform diffusion annealing heat treatment.

7. The preparation method of the bend-free crack nickel-based superalloy according to claim 6, characterized in that, The temperature of the smelting is 1550~1650°C, and the time is 0.5~1 hour.

8. The preparation method of the bend crack-free nickel-based superalloy according to claim 6 or 7, characterized in that the diffusion annealing heat treatment is to heat the ingot blank to 1180 - 1220°C, hold for 48 - 60 h, and air-cool to room temperature.

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