A nickel-based superalloy and a preparation method and application thereof

Abstract

The application discloses a nickel-based high-temperature alloy, which comprises the following components: C: 0.04-0.08%, Cr: 18.00-21.50%, Co: 8.00-12.00%, Mo: 7.00-9.00%, Al: 1.20-1.80%, Ti: 1.90-2.10%, Nb: 0.02-0.1%, W: 0.8-1.8%, Zr: 0.07-0.1%, B: 0.001-0.01%, and the balance is nickel and inevitable impurities, and the mass percentage is calculated. The mass percentage of the elements B and Zr in the alloy satisfies the relationship formula: 0.11% < 10B+Zr < 0.158%. The nickel-based high-temperature alloy has excellent mechanical properties, creep resistance, endurance life and solidification performance, and can meet the requirements of an aero-engine and a gas turbine, and is suitable for manufacturing precise hot end parts of the aero-engine and the gas turbine, a rocket engine, an ultra-supercritical coal-fired power plant and an automobile engine.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature alloy technology, specifically relating to a nickel-based high-temperature alloy, particularly to a method for preparing the nickel-based high-temperature alloy, and further relating to the application of the nickel-based high-temperature alloy. Background Technology

[0002] With the continuous development of the design level and application technology of aero-engines and gas turbines, the initial temperature of the gas is getting higher and higher. In the future, the initial temperature of the gas will reach 1600-1700℃, and the temperature that the alloy body of the precision hot end component of aero-engines and gas turbines will withstand will also reach 800-950℃. Therefore, the requirements for the high-temperature mechanical properties of alloys at 800-950℃ are becoming increasingly stringent.

[0003] While current high-temperature alloys possess excellent machinability, most of these alloys can only serve for extended periods below 800°C. Above 800°C, they exhibit insufficient high-temperature performance. For example, at higher temperatures, the microstructure loses stability, leading to performance degradation. They also have high content and rapid precipitation of the reinforcing phase γ′, making hot working (forging, hot rolling), heat treatment of billets, and cold working (cold bending, turning, welding, etc.) of parts quite challenging. Consequently, they are unsuitable for manufacturing precision hot-end components in aero-engines and gas turbines that require complex machining processes.

[0004] Therefore, there is an urgent need to study and improve the comprehensive properties of nickel-based superalloys. Summary of the Invention

[0005] This invention is based on the inventor's discovery and understanding of the following facts and problems: Currently, there are strict requirements for the high-temperature performance of precision hot-end components of aero engines and gas turbines, but existing alloys cannot meet these requirements. It is necessary to improve the technology of high-temperature alloys to enhance their overall performance.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, this invention proposes a nickel-based high-temperature alloy with excellent mechanical properties, creep resistance, rupture life, and solidification properties, which can meet the requirements of aero-engines and gas turbines. It is suitable for manufacturing precision hot-end components of aero-engines and gas turbines, and can also be used to manufacture rocket engines, ultra-supercritical coal-fired power plants, or automobile engines.

[0008] The nickel-based superalloy of this invention comprises: C: 0.04-0.08%, Cr: 18.00-21.50%, Co: 8.00-12.00%, Mo: 7.00-9.00%, Al: 1.20-1.80%, Ti: 1.90-2.10%, Nb: 0.02-0.1%, W: 0.8-1.8%, Zr: 0.07-0.1%, B: 0.001-0.01%, with the balance being nickel and unavoidable impurities, in mass percentage.

[0009] The advantages and technical effects of the nickel-based superalloy of this invention are as follows: 1. In the alloy of this invention, the amount of Zr element is increased. Zr segregates to the grain boundaries, reducing grain boundary defects, improving grain boundary bonding force, and reducing grain boundary diffusion rate, thereby slowing down dislocation climb and strengthening grain boundaries. At the same time, Zr segregation to the grain boundaries can reduce interfacial energy, change the morphology of the grain boundary phase, reduce the size of the grain boundary phase, and effectively organize grain sliding along the grain boundaries, thereby improving creep life, improving creep plasticity, and eliminating notch sensitivity. In addition, Zr can also act as a purifying agent, combining with C and S to form primary sulfides or carbosulfides, reducing the C and S content in the alloy. Most of the Zr added to the alloy enters the superalloy. The addition of Zr increases the dissolution temperature and content of the γ' phase, but excessive Zr addition will significantly increase the tendency for hot cracking during the solidification of the directional solidification master alloy. Therefore, in this embodiment, the amount of Zr added is controlled at 0.07-0.1%. 2. In this embodiment, the W content is limited to 0.8-1.8%. In nickel-based superalloys, W dissolves in the γ matrix and the γ' phase, each accounting for approximately half. W has a larger atomic radius, 10-13% larger than that of Ni, Co, and Fe. W atoms in the superalloy matrix cause significant lattice expansion, forming a large long-range stress field, inhibiting dislocation movement, and significantly increasing the yield strength. W significantly reduces the stacking fault energy of the γ matrix, thus effectively... To improve the creep properties of high-temperature alloys, increasing the W content significantly reduces stacking fault energy and improves creep resistance. Besides the solid solution strengthening effect, W atoms enter the γ' phase and influence the distribution of other elements between the γ matrix and the γ' phase, altering the lattice constant and mismatch degree of the γ matrix and γ' phase, thus increasing alloy strength. However, excessive W will promote the formation of M6C and μ phases, which will affect the mechanical properties of the alloy. Therefore, the W content is limited to 0.8-1.8%. 3. In this embodiment of the invention, the Mo content is limited. Unlike W, most Mo atoms dissolve in the γ matrix, accounting for about 1 / 4 of the γ' phase. Mo atoms are also relatively large, 9-1.8% larger than Ni, Co, and Fe atoms. 12% Mo significantly increases the lattice constant of Ni solid solution and significantly improves the yield strength at both room temperature and high temperature. The addition of Mo also forms a large number of M6C carbides. These carbides are fine and dispersed, which can also play a strengthening role. Mo can also refine austenite grains. However, adding too much Mo will promote the formation of μ phase, which is detrimental to long-term microstructure stability. Therefore, the Mo content is controlled at 7.00-9.00%. 4. The alloy of the embodiments of the present invention, through reasonable element ratio, obtains a high-temperature alloy with excellent comprehensive performance. It can be used to manufacture precision hot-end components of aero engines and gas turbines, and can also be used to manufacture rocket engines, ultra-supercritical coal-fired power plants or automobile engines.

[0010] In some embodiments, the mass percentages of elements B and Zr in the alloy satisfy the relationship: 0.11% < 10B + Zr < 0.158%.

[0011] In some embodiments, the mass percentages of elements B and Zr in the alloy satisfy the relationship: 0.14% < 10B + Zr < 0.158%.

[0012] In some embodiments, the W content is 1.3-1.8%.

[0013] In some embodiments, the Zr content is 0.09-0.1%.

[0014] In some embodiments, the impurities are Fe ≤ 1.50%, Si ≤ 0.10%, Mn ≤ 0.10%, P ≤ 0.008%, S ≤ 0.008%, and Cu ≤ 0.20%.

[0015] This invention also provides a method for preparing a nickel-based superalloy, comprising the following steps:

[0016] a. Take the raw materials in the designed proportion, melt and refine them, and cast them into alloy ingots;

[0017] b. Forge the alloy ingot obtained in step a into an electrode rod, remelt it to obtain another alloy ingot, forge it again, process it, and then perform heat treatment.

[0018] The advantages and technical effects of the preparation method of nickel-based superalloys in this embodiment of the invention are as follows: The method of this embodiment of the invention is simple and easy to apply. The nickel-based superalloys obtained have excellent mechanical properties, creep resistance, rupture life and solidification properties, which can meet the requirements of aero engines, gas turbines, rocket engines and the like.

[0019] In some embodiments, step b, the heat treatment includes solution treatment and aging treatment.

[0020] This invention also provides an application of nickel-based superalloys in aero engines or gas turbines.

[0021] The nickel-based superalloys of this invention meet the design and use requirements of aero-engines or gas turbines and can be applied in precision equipment of aero-engines or gas turbines.

[0022] This invention also provides an application of nickel-based superalloys in rocket engines, ultra-supercritical coal-fired power plants, or automobile engines.

[0023] The nickel-based superalloys of this invention exhibit excellent performance and can be used in rocket engines, ultra-supercritical coal-fired power plants, or automobile engines. Detailed Implementation

[0024] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] The nickel-based superalloy of this invention comprises: C: 0.04-0.08%, Cr: 18.00-21.50%, Co: 8.00-12.00%, Mo: 7.00-9.00%, Al: 1.20-1.80%, Ti: 1.90-2.10%, Nb: 0.02-0.1%, W: 0.8-1.8%, Zr: 0.07-0.1%, B: 0.001-0.01%, with the balance being nickel and unavoidable impurities, in mass percentage.

[0026] The nickel-based superalloy of this invention increases the amount of Zr. Zr segregates to grain boundaries, reducing grain boundary defects, increasing grain boundary bonding strength, and decreasing grain boundary diffusion rate, thereby slowing dislocation climb and strengthening grain boundaries. Simultaneously, Zr segregation to grain boundaries reduces interfacial energy, alters the morphology of the grain boundary phase, reduces the size of the grain boundary phase, and effectively prevents grains from sliding along grain boundaries, thus improving creep life, enhancing creep ductility, and eliminating notch sensitivity. Furthermore, Zr can act as a purifying agent, combining with C and S to form primary sulfides or carbosulfides, reducing the C and S content in the alloy. Most of the Zr added to the alloy enters the γ' phase, increasing the γ' phase dissolution temperature and reducing its content. While increasing the amount of Zr is beneficial, excessive Zr addition will significantly increase the tendency for hot cracking during solidification of the directional solidification master alloy. Therefore, in this embodiment, the Zr addition is controlled at 0.07-0.1%. In this embodiment, the W content is limited to 0.8-1.8%. In nickel-based superalloys, W dissolves in the γ matrix and γ' phase, each accounting for approximately half. W has a larger atomic radius, 10-13% larger than that of Ni, Co, and Fe. W atoms cause significant lattice expansion in the superalloy matrix, forming a large long-range stress field, inhibiting dislocation movement, and significantly improving the yield strength. W also significantly reduces the stacking fault energy of the γ matrix, thus effectively improving the creep properties of the superalloy. With increasing W content, stacking fault energy decreases significantly, and creep resistance improves markedly. Besides the solid solution strengthening effect mentioned above, W atoms enter the γ' phase and influence the distribution of other elements between the γ matrix and the γ' phase, altering the lattice constant and mismatch degree of the γ matrix and γ' phase, thus increasing alloy strength. However, excessive W will promote the formation of M6C and μ phases, which will affect the mechanical properties of the alloy. Therefore, the W content is limited to 0.8-1.8%. In this embodiment, the Mo content is also limited. Unlike W, most Mo atoms dissolve in the γ matrix, accounting for about 1 / 4 in the γ' phase. Mo atoms are also relatively large, 9-12% larger than Ni, Co, and Fe atoms. The addition of Mo significantly increases the lattice constant of Ni solid solution and significantly improves the yield strength at both room temperature and high temperature. Furthermore, the addition of Mo forms a large number of M6C carbides, which are fine and dispersed, thus also playing a strengthening role. Mo can also refine austenite grains. However, excessive Mo addition will promote the formation of the μ phase, which is detrimental to long-term microstructure stability. Therefore, the Mo content is controlled at 7.00-9.00%. The alloys of this invention, through reasonable element ratios, yield high-temperature alloys with excellent comprehensive performance. These alloys can be used to manufacture precision hot-end components for aero-engines and gas turbines, and can also be used to manufacture rocket engines, ultra-supercritical coal-fired power plants, or automobile engines.

[0027] In some embodiments, the mass percentages of elements B and Zr in the alloy satisfy the relationship: 0.11% < 10B + Zr < 0.158%, more preferably, 0.14% < 10B + Zr < 0.158%. In this embodiment of the invention, preferably, the relationship between B and Zr can be further limited to 0.11% < 10B + Zr < 0.158%. Both B and Zr, when added individually, can significantly improve the alloy's creep life, creep ductility, and creep resistance. The combined addition of both is more effective than adding them individually, further improving the alloy's creep life. However, when too much B and Zr are added, a thin film-like brittle phase is easily formed at the grain boundaries, which is detrimental to the alloy's ductility and also makes it prone to solidification cracks.

[0028] In some embodiments, the W content is preferably 1.3-1.8%; the Zr content is preferably 0.09-0.1%. In these embodiments of the invention, the optimized W and Zr content is beneficial for further improving the overall performance of the alloy.

[0029] In some embodiments, the impurities are Fe≤1.50%, Si≤0.10%, Mn≤0.10%, P≤0.008%, S≤0.008%, and Cu≤0.20%. In these embodiments, the content of impurity elements is limited, thus not affecting the alloy's performance.

[0030] This invention also provides a method for preparing a nickel-based superalloy, comprising the following steps:

[0031] a. Take the raw materials in the designed proportion, melt and refine them, and cast them into alloy ingots;

[0032] b. Forge the alloy ingot obtained in step a into an electrode rod, remelt it to obtain another alloy ingot, forge it again, process it, and then perform heat treatment.

[0033] The method for preparing nickel-based superalloys according to embodiments of the present invention is simple and easy to apply. The resulting nickel-based superalloys have excellent mechanical properties, creep resistance, rupture life, and solidification properties, which can meet the requirements of aero engines, gas turbines, rocket engines, etc.

[0034] In some embodiments, step b, the heat treatment includes solution treatment and aging treatment.

[0035] This invention also provides an application of a nickel-based superalloy in aero-engines or gas turbines. The nickel-based superalloy of this invention meets the design and usage requirements of aero-engines or gas turbines and can be used in precision equipment within these engines.

[0036] This invention also provides an application of a nickel-based superalloy in rocket engines, ultra-supercritical coal-fired power plants, or automobile engines. The nickel-based superalloy of this invention exhibits excellent performance and can be used in rocket engines, ultra-supercritical coal-fired power plants, or automobile engines.

[0037] The present invention will now be described in detail with reference to the embodiments.

[0038] Example 1

[0039] Raw materials are weighed according to the design ratio and placed in a melting furnace for vacuum melting. After all the raw materials have melted, they are refined to remove gases. After refining, they are cast into alloy ingots under vacuum conditions. The alloy ingots are forged into electrode rods, remelted to obtain alloy ingots, forged into blanks, forged and rolled into 20mm thick plates, and then subjected to solution treatment at 1150℃ for 1 hour, water cooling, and aging treatment at 1010℃ for 2 hours and 788℃ for 8 hours to obtain nickel-based high-temperature alloys. The alloy composition is shown in Table 1 and the properties are shown in Table 2.

[0040] The preparation methods of Examples 2-10 are the same as those of Example 1, except that the alloy composition is different. The alloy composition of Examples 2-10 is shown in Table 1, and the properties are shown in Table 2.

[0041] Comparative Example 1

[0042] The preparation method of Comparative Example 1 is the same as that of Example 1, except that the content of element W in the alloy composition is 0.03. The alloy composition of Comparative Example 1 is shown in Table 1, and the properties are shown in Table 2.

[0043] Comparative Example 2

[0044] Comparative Example 2 was prepared using the same method as Example 1, except that the content of element W in the alloy composition was 0.01. The alloy composition of Comparative Example 2 is shown in Table 1, and the properties are shown in Table 2.

[0045] Comparative Example 3

[0046] The preparation method of Comparative Example 3 is the same as that of Example 1, except that the content of element Zr in the alloy composition is 0.03. The alloy composition of Comparative Example 3 is shown in Table 1, and the properties are shown in Table 2.

[0047] Comparative Example 4

[0048] Comparative Example 4 was prepared using the same method as Example 1, except that the Zr content in the alloy composition was 0.012. The alloy composition of Comparative Example 4 is shown in Table 1, and the properties are shown in Table 2.

[0049] Comparative Example 5

[0050] Comparative Example 5 was prepared using the same method as Example 1, except that the alloy composition contained 0.05% W and 0.02% Zr. The alloy composition of Comparative Example 1 is shown in Table 1, and its properties are shown in Table 2.

[0051] Comparative Example 6

[0052] Comparative Example 6 was prepared using the same method as Example 1, except that the alloy composition contained 0.08% W and 0.045% Zr. The alloy composition of Comparative Example 6 is shown in Table 1, and its properties are shown in Table 2.

[0053] Comparative Example 7

[0054] Comparative Example 7 was prepared using the same method as Example 1, except that the alloy composition contained 2.3% W and 0.015% Zr. The alloy composition of Comparative Example 7 is shown in Table 1, and its properties are shown in Table 2.

[0055] Comparative Example 8

[0056] The preparation method of Comparative Example 8 is the same as that of Example 1, except that the content of element W in the alloy composition is 0.03% and Zr is 0.15%. The alloy composition of Comparative Example 8 is shown in Table 1 and the properties are shown in Table 2.

[0057] Comparative Example 9

[0058] Comparative Example 9 was prepared using the same method as Example 1, except that the alloy composition contained 2.10% W and 0.12% Zr. The alloy composition of Comparative Example 9 is shown in Table 1, and its properties are shown in Table 2.

[0059] Comparative Example 10

[0060] Comparative Example 10 was prepared using the same method as Example 1, except that the alloy composition contained 2.20% W and 0.14% Zr. The alloy composition of Comparative Example 10 is shown in Table 1, and its properties are shown in Table 2.

[0061] Table 1

[0062]

[0063] Note: The content of each element in the table is expressed in wt%.

[0064] Table 2

[0065]

[0066] Note: 1. ε p The creep plastic elongation of the aged alloy under conditions of 816℃, 221MPa, and 100h is given.

[0067] 2. τ is the creep rupture life of the aged alloy under conditions of 89 MPa and 927 °C, and δ is the elongation after creep rupture of the aged alloy under conditions of 89 MPa and 927 °C.

[0068] 3. R p0.2 For the room temperature tensile yield strength of aged alloys, R m Let A be the room temperature tensile strength of the aged alloy, and let A be the room temperature tensile elongation after fracture of the aged alloy.

[0069] 4. The detection conditions for solidification cracks are as follows: after the steel ingot is cast, it is cooled with the mold for 8 hours, and the surface is inspected after demolding.

[0070] 5. The 10B+Zr in the table is expressed in wt%.

[0071] As can be seen from Tables 1 and 2, in Examples 1-10, the creep plastic elongation was all below 0.2%, the rupture life of the alloys under the conditions of 89 MPa and 927℃ was all above 330h, the room temperature tensile yield strength was all above 750 MPa, the room temperature tensile tensile strength was all above 1100 MPa, the room temperature tensile elongation after fracture A was all above 30%, and there were no solidification cracks, indicating excellent comprehensive performance.

[0072] In Comparative Examples 1-2, the low amount of W resulted in poor creep performance of the alloy, exceeding 0.8%, and the creep rupture life was only about 200 hours. In Comparative Examples 3-4, the low amount of Zr resulted in good creep performance of the alloy, but the creep rupture life was only about 200 hours. In Comparative Examples 5-6, the low amounts of both W and Zr resulted in severely poor creep performance of the alloy, both exceeding 0.8%, and the creep rupture life was low, less than 200 hours. In Comparative Example 7, a relatively high amount of W was added. In Comparative Example 8, the amount of W was reduced and the amount of Zr was increased. Although the creep life reached 460 hours, the creep performance was poor and decreased. The elongation at room temperature after tensile fracture (A) also decreased significantly to only 15%, and solidification cracks appeared. In Comparative Examples 9 and 10, the amounts of W and Zr were increased. Although they had excellent creep performance and creep life, the elongation (A) decreased significantly to less than 20%, and solidification cracks appeared.

[0073] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A nickel-base superalloy characterized by, The alloy comprises: C: 0.04-0.08%, Cr: 18.00-21.50%, Co: 8.00-12.00%, Mo: 7.00-9.00%, Al: 1.20-1.80%, Ti: 1.90-2.10%, Nb: 0.02-0.08%, W: 0.8-1.8%, Zr: 0.07-0.1%, B: 0.001-0.01%, with the balance being nickel and unavoidable impurities, in mass percentage. The mass percentages of elements B and Zr in the alloy satisfy the relationship: 0.15% < 10B + Zr < 0.158%.

2. The nickel-base superalloy of claim 1, wherein, The W content is 1.3-1.8%.

3. The nickel-base superalloy of claim 1, wherein, The Zr content is 0.09-0.1%.

4. The nickel-base superalloy of claim 1, wherein, The impurities are Fe≤1.50%, Si≤0.10%, Mn≤0.10%, P≤0.008%, S≤0.008%, and Cu≤0.20%.

5. A method of producing the nickel-based superalloy as claimed in any one of claims 1 to 4, characterized in that Includes the following steps: a. Take the raw materials in the designed proportion, melt and refine them, and cast them into alloy ingots; b. Forge the alloy ingot obtained in step a into an electrode rod, remelt it to obtain another alloy ingot, forge it again, process it, and then perform heat treatment.

6. The method of producing a nickel-based superalloy according to claim 5, characterized in that, In step b, the heat treatment includes solution treatment and aging treatment.

7. The application of the nickel-based superalloy according to any one of claims 1-4 in aero engines or gas turbines.

8. The application of the nickel-based superalloy according to any one of claims 1-4 in rocket engines, ultra-supercritical coal-fired power plants or automobile engines.

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