Iron-nickel-cobalt superalloy and preparation method therefor

Abstract

An iron-nickel-cobalt superalloy and a preparation method therefor. The superalloy comprises the following components in percentage by mass: Cr: 6%-8%; Mo: 1%-2%; Ti: 1%-2%; Re: 0.5%-1%; Hf: 2.5%-3%; Y: 1%-3%; Nb: 0.3%-0.5%; Ge: 0.1%-0.2%; Ce: 0.05%-0.1%; Fe: 14%-20%; Co: 10%-15%; the remainder being Ni; and inevitable impurities such as C and P. By means of reasonable element proportions and multi-stage heat treatment, the superalloy exhibits excellent creep resistance, fatigue resistance and oxidation resistance in a high-temperature environment.

Description

A high-temperature iron-nickel-cobalt alloy and its preparation method Technical Field

[0001] This invention relates to the technical field of metallic materials, and in particular to an iron-nickel-cobalt high-temperature alloy and its preparation method. Background Technology

[0002] As the demands on material properties in high-temperature environments continue to increase, iron-nickel-cobalt (FeNiCo) superalloys, due to their excellent mechanical properties and high-temperature stability, have been widely used in aerospace, energy, and metallurgy, especially under extreme conditions such as gas turbine engines and high-temperature reactors. Traditional FeNiCo superalloys often improve their strength, oxidation resistance, and creep resistance by adding elements such as nickel, cobalt, and chromium. However, with increasingly demanding high-temperature operating conditions, the performance of traditional alloys still faces challenges, particularly in terms of durability, oxidation resistance, corrosion resistance, and creep resistance at high temperatures.

[0003] Existing high-temperature alloy formulations and preparation processes still have some problems, such as uneven composition distribution, unstable microstructure, and insufficient fatigue resistance, which limit their application in higher temperatures and more complex environments. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an iron-nickel-cobalt high-temperature alloy and its preparation method.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A high-temperature alloy of iron, nickel, and cobalt, wherein the composition of the high-temperature alloy by mass percentage is:

[0007] Cr: 6%-8%, Mo: 1%-2%, Ti: 1%-2%, Re: 0.5%-1%, Hf: 2.5%-3%, Y: 1%-3%, Nb: 0.3-0.5%; Ge: 0.1-0.2%; Ce: 0.05%-0.1%, Fe: 14%-20%, Co: 10%-15%, Ni: balance, and unavoidable impurities such as C and P.

[0008] The main functions of the various elements added to iron-nickel-cobalt superalloys are as follows:

[0009] Iron, nickel, and cobalt are the main elements in this alloy. Cobalt and iron, together with nickel, form the alloy's matrix structure. Nickel (Ni) is the matrix element, providing the material's toughness and ductility, while the introduction of cobalt significantly improves high-temperature strength and reduces creep. At high temperatures, cobalt helps stabilize the alloy's crystal structure, preventing plastic deformation or creep. Iron enhances the overall strength of the matrix while maintaining the material's toughness and durability. Together, these elements contribute to the alloy's excellent stability in high-temperature environments.

[0010] Specifically, the synergistic effect of nickel and iron forms a robust matrix structure, providing stable mechanical properties and fatigue resistance, and enhancing the high-temperature stability of the matrix without affecting overall ductility and impact resistance. The synergistic effect of nickel and cobalt reduces creep, allowing the material to maintain strength and durability in extreme high-temperature environments, significantly improving its high-temperature creep strength. Furthermore, the combined effect of cobalt and iron slows down the creep behavior of the alloy under high-temperature stress, making it more suitable for long-term operation under high-temperature conditions.

[0011] The addition of chromium (Cr) provides excellent oxidation and corrosion resistance to the alloy. At high temperatures, chromium rapidly forms a dense chromium oxide protective film, preventing the penetration of oxygen and other corrosive media. Molybdenum (Mo), as a solid solution strengthening element, significantly improves the high-temperature strength of the alloy. Molybdenum also prevents excessive grain growth in high-temperature environments, ensuring the alloy maintains a fine and stable structure under prolonged high temperatures. When chromium and molybdenum are added together, they have a synergistic effect. The synergy of chromium and molybdenum reduces grain boundary slip, enhances the alloy's stability at high temperatures, and further strengthens its overall corrosion resistance, enabling the material to maintain chemical stability in extreme environments and preventing premature aging or failure. Furthermore, through process control during alloy preparation, multi-stage aging treatment, and multi-level precipitation effects, molybdenum-rich phases and Cr-Mo eutectoid phases are formed in the alloy, further improving the material's creep resistance and high-temperature strength, enhancing grain boundary stability and fatigue resistance, thereby improving the alloy's performance at high temperatures.

[0012] Secondly, chromium and cobalt also have a certain synergistic effect. Together, they enhance the stability of the formed antioxidant layer and enable the material to exhibit good antioxidant and corrosion resistance during long-term use.

[0013] The synergistic effect of niobium and germanium in high-temperature alloys can significantly improve their overall performance. Niobium, as an important strengthening element, can form high-temperature stable intermetallic compounds (such as NbC) with carbon. These carbides are distributed in the alloy matrix as fine, dispersed particles, effectively hindering dislocation movement and enhancing the alloy's high-temperature strength and creep resistance. Simultaneously, the addition of niobium can also promote the stability of certain strengthening phases (such as the γ′ or γ″ phase), giving them longer-lasting thermal stability at high temperatures and significantly delaying the alloy's performance degradation.

[0014] Germanium's role in high-temperature alloys is primarily manifested in two aspects: oxidation resistance and toughness enhancement. At high temperatures, germanium works synergistically with traditional antioxidants (such as chromium and nickel) to promote the density and stability of the oxide film, thereby improving the alloy's durability in oxidizing and sulfiding environments. Furthermore, the presence of germanium can optimize the alloy's electronic structure and enhance metallic bond strength, thus improving the overall toughness of the alloy and reducing the risk of crack propagation during high-temperature operation. Simultaneously, the addition of germanium may affect the distribution and morphology of the γ′ phase, further optimizing the alloy's microstructure.

[0015] The synergistic effect of niobium and germanium is also reflected in their joint participation in strengthening the matrix and interfacial bonding. Niobium carbides enhance the matrix strength, while germanium's electronic structure adjustment improves the alloy's plastic deformation capability. Their combination achieves a better balance between high-temperature creep and fatigue resistance. This balance is particularly important for alloys used in extreme high-temperature environments, such as turbine blade materials. Titanium (Ti) is an important precipitating element for strengthening alloys. Titanium can form the γ' phase (Ni3Ti), providing precipitation hardening at high temperatures, improving creep resistance and high-temperature strength. Furthermore, titanium improves the alloy's hardness and stability through the formation of precipitated phases. The addition of hafnium (Hf) aims to strengthen grain boundaries, improving the material's creep resistance and high-temperature toughness. Hafnium can form stable compounds at grain boundaries, preventing grain boundary slip and delaying creep and crack propagation. Moreover, hafnium can improve bonding forces at grain boundaries, reducing crack initiation and propagation.

[0016] When titanium and hafnium are added to an alloy, the introduction of hafnium can stabilize and refine the γ' phase (Ni3Ti) formed by titanium, making it more stable at high temperatures. This helps to delay phase coarsening and failure, thereby extending the material's service life and high-temperature performance. Secondly, hafnium forms stabilizing compounds at grain boundaries, enhancing grain boundary bonding, preventing grain boundary slip, and reducing creep and crack propagation. This grain boundary strengthening effect complements the precipitation strengthening mechanism formed by titanium, improving the overall high-temperature creep resistance of the alloy.

[0017] Trace amounts of carbon react with hafnium during alloy smelting to precipitate hafnium carbide (HfC). As a strong carbide, HfC maintains a fine grain structure at high temperatures, providing excellent grain boundary strengthening and preventing grain growth and structural deformation. This enhances the alloy's stability and oxidation resistance at ultra-high temperatures without significantly increasing brittleness. Yttrium oxide promotes grain boundary stability at higher temperatures, delaying creep and fatigue failure by inhibiting grain boundary slip and dislocation climb. The enhanced oxidation resistance of hafnium carbide at higher temperatures, combined with the grain boundary stabilizing effect of yttrium oxide, further improves the alloy's stability under ultra-high temperature and high stress environments.

[0018] During the alloy smelting process, yttrium absorbs trace amounts of oxygen from the melt, causing some of the yttrium to precipitate as yttrium oxide. These yttrium oxide particles act as pinning agents at grain boundaries, inhibiting grain slip and significantly improving the alloy's high-temperature creep resistance. The yttrium content needs to be controlled within the range of 1%-3%. Too low a content will limit the formation of yttrium oxide, while too high a content may lead to particle aggregation or coarsening.

[0019] The combined effect of yttrium oxide, hafnium carbide, hafnium, and titanium further enhances the stability of the material under high-temperature conditions, reduces performance degradation caused by oxidation, and further improves the creep resistance of the material under high-temperature stress conditions, ensuring the long life and durability of the material.

[0020] Rhenium (Re) is an extremely important solid solution strengthening element. Although its content is relatively low, its effect on improving the high-temperature performance of alloys is very significant. Rhenium has a high melting point and can inhibit grain boundary slip, thereby preventing deformation and creep of the alloy at high temperatures. Rhenium improves the stability of grain boundaries through solid solution strengthening, which allows the alloy to maintain good mechanical properties even at extreme temperatures. Secondly, rhenium and hafnium have a synergistic effect, jointly enhancing grain boundary stability and high-temperature strength: rhenium inhibits grain boundary movement, while hafnium increases the bonding strength of grain boundaries, thereby further delaying high-temperature creep behavior.

[0021] This invention also incorporates the rare earth element cerium (Ce). Although the amount of cerium (Ce) added is small, it plays a crucial role in suppressing impurity elements and improving the alloy's oxidation resistance. Ce can combine with impurity elements such as oxygen and sulfur, reducing their negative impact on the alloy's performance. Secondly, cerium can form a dense protective film on the alloy surface and at grain boundaries. This, combined with the stable compounds formed by hafnium and rhenium, helps improve the material's oxidation and corrosion resistance. Furthermore, the combination of titanium and cerium further enhances the overall stability of the alloy: the precipitation strengthening effect of titanium becomes more durable under the influence of cerium, which improves the stability of the precipitated phase and enhances oxidation resistance.

[0022] Therefore, the present invention can achieve comprehensive high-temperature strengthening by adjusting the distribution of rhenium and hafnium in the nanostructure and adding titanium and the rare earth element cerium.

[0023] Furthermore, the niobium content in the high-temperature alloy ranges from 0.4% to 0.45%.

[0024] Furthermore, the chromium content in the high-temperature alloy ranges from 6.7% to 7.3%.

[0025] Furthermore, the molybdenum content in the high-temperature alloy ranges from 1.2% to 1.8%.

[0026] Furthermore, the titanium content in the high-temperature alloy ranges from 1.3% to 1.7%.

[0027] Furthermore, the rhenium content in the high-temperature alloy ranges from 0.7% to 0.8%.

[0028] Furthermore, the hafnium content in the high-temperature alloy ranges from 2.6% to 2.7%.

[0029] Furthermore, the germanium content in the high-temperature alloy ranges from 0.1% to 0.16%.

[0030] Furthermore, the yttrium content in the high-temperature alloy ranges from 1.7% to 2.3%.

[0031] A method for preparing the above-mentioned iron-nickel-cobalt superalloy includes the following steps:

[0032] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600-1650℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2-3 hours. The nickel and iron raw materials are particles with a porous structure.

[0033] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2-3A / cm², the melting temperature is set at 1500-1550℃, and the remelting process lasts for 3-4 hours.

[0034] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 6-8 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0035] S4: Heat treatment process:

[0036] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0037] (2) Multi-stage time-sensitive processing:

[0038] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0039] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0040] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0041] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0042] Step S1 ensures the compositional homogeneity of the alloy and reduces inclusions and porosity, improving the alloy's purity and initial structural properties. Step S2, electroslag remelting, further refines the alloy, removing harmful impurities, improving the uniformity and density of the microstructure, and contributing to a refined grain structure, thereby enhancing the alloy's mechanical properties. Step S3, the slow cooling process, helps reduce the formation of thermal and internal stresses, thus preventing ingot cracks and internal defects. Step S4, the solution treatment, ensures the stability of the alloy's solid solution structure, eliminates coarse precipitates in the as-cast microstructure, and increases the material's machinability and resistance to deformation.

[0043] In step S1, the nickel and iron raw materials are particles with a porous structure, which allows the nickel and iron raw materials to adsorb trace amounts of oxygen. As a result, during the smelting process, the yttrium element can combine with oxygen to generate yttrium oxide.

[0044] The rapid cooling rate in the early stage of step S3 (2℃ / min) effectively promotes rapid grain nucleation, avoids the formation of coarse grains, and improves grain refinement. The slower cooling rate in the later stage (1℃ / min) reduces the accumulation of thermal stress during grain growth, ensuring uniform grain size. Staged cooling helps control the precipitation behavior of carbides (such as NbC) and other reinforcing phases (such as γ′ phase). Early cooling rapidly dissolves some solute elements, while slow cooling in the later stage promotes the uniform distribution of precipitated particles. Staged cooling optimizes the dislocation structure and phase distribution in the microstructure, thus exhibiting superior creep resistance and thermal stability at high temperatures.

[0045] The first aging stage promotes the formation of fine precipitated strengthening phases, such as the initial precipitation of molybdenum-rich phase, significantly improving the material's creep resistance and high-temperature strength. The second aging stage facilitates the further precipitation of Cr-Mo eutectoid phases, enhancing grain boundary stability and the material's fatigue resistance. The third aging stage further refines and uniformly distributes the molybdenum-rich strengthening zone, optimizing the overall properties of the alloy and ensuring the material's stability and long-term reliability in high-temperature environments.

[0046] Step S5 significantly improves the toughness and durability of the material by eliminating micropores and grain boundary defects.

[0047] Multi-stage aging treatment not only strengthens the molybdenum and chromium precipitation effect in the alloy matrix, but also significantly affects the effects of HfC formed by the combination of hafnium and carbon, and Y2O3 formed by the combination of yttrium and oxygen. HfC, due to its high melting point and chemical stability, enables the alloy to maintain stability and oxidation resistance under ultra-high temperature conditions. Through multi-stage aging, HfC achieves a more uniform distribution in the matrix, reducing its potential negative impact on material brittleness. By controlling the aging temperature and time, HfC particles can form a stable, fine distribution within the matrix, correspondingly improving the overall strength of the alloy.

[0048] Y₂O₃, as a grain refiner and dislocation motion inhibitor, also exhibits unique roles in multi-stage aging treatment. During aging, Y₂O₃ can promote the stability of alloy grain boundaries at higher temperatures, delaying creep and fatigue failure by inhibiting grain boundary slip and dislocation climb. Multi-stage aging treatment can also promote the formation of eutectic or interfacial interactions between Y₂O₃ particles and the strengthening phases precipitated by molybdenum and chromium at high temperatures, further enhancing the high-temperature mechanical properties of the matrix.

[0049] From a synergistic perspective, the presence of HfC and Y2O3 enhances the multiphase strengthening effect of the alloy during multi-stage aging treatment. HfC enhances oxidation resistance at higher temperatures, and its combination with the grain boundary stabilizing effect of Y2O3 further improves the alloy's stability under ultra-high temperature and high stress environments. The dislocation suppression effect of Y2O3 can also interact with the precipitation of molybdenum and chromium, reducing dislocation accumulation and deformation instability, thus improving fatigue resistance. The synergistic effect of both in multi-stage aging treatment gives the alloy excellent comprehensive mechanical properties and thermal stability during long-term high-temperature service.

[0050] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in the following aspects:

[0051] The iron-nickel-cobalt superalloy and its preparation method provided by this invention achieve significant performance improvements through optimization of alloy composition and preparation process. This superalloy, through reasonable elemental ratios and multi-stage heat treatment, exhibits excellent creep resistance, fatigue resistance, and oxidation resistance in high-temperature environments. The synergistic effect of elements such as nickel, cobalt, and chromium in the alloy not only enhances the material's high-temperature strength but also effectively improves its oxidation and corrosion resistance, giving the alloy better stability and a longer service life under extreme high temperatures.

[0052] Through refining processes involving vacuum induction melting and electroslag remelting, the alloy composition is uniformly distributed, impurities and porosity are effectively removed, and purity and density are improved, thereby enhancing the material's mechanical properties. Multi-stage aging treatment effectively promotes the precipitation of elements such as molybdenum, chromium, titanium, and rhenium in the alloy, forming strengthening phases and improving the material's creep resistance and high-temperature strength. In particular, the synergistic effect of titanium and hafnium enhances the alloy's crack resistance and grain boundary stability, enabling it to maintain good mechanical properties at high temperatures.

[0053] Furthermore, the precipitation of hafnium carbide and yttrium oxide further enhances the high-temperature performance of the alloy by refining grains and stabilizing grain boundaries, inhibiting grain growth and the generation of thermal stress, and reducing deformation and crack propagation of the material at high temperatures. Hafnium carbide provides excellent hardness and wear resistance, while yttrium oxide acts as a grain refiner, effectively improving the alloy's creep resistance and oxidation resistance.

[0054] During the multi-stage aging process, the strengthening phase is uniformly distributed through precise control of temperature and time, thereby improving the overall performance of the alloy at high temperatures. In practical applications, this iron-nickel-cobalt superalloy can operate stably for extended periods in high-temperature, oxidizing, and corrosive environments, demonstrating broad application prospects, particularly suitable for aerospace, energy, and high-temperature industrial fields. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the embodiments. Example

[0056] This embodiment discloses an iron-nickel-cobalt superalloy and its preparation method, wherein the chemical composition of the iron-nickel-cobalt superalloy is as follows (by mass percentage):

[0057] Cr: 6%, Mo: 1%, Ti: 1%, Re: 0.5%, Hf: 2.5%, Y: 1%, Nb: 0.3%; Ge: 0.1%; Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0058] The preparation method of this iron-nickel-cobalt superalloy includes the following steps:

[0059] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0060] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0061] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 6 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0062] S4: Heat treatment process:

[0063] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0064] (2) Multi-stage time-sensitive processing:

[0065] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0066] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0067] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0068] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling. Example

[0069] This embodiment discloses an iron-nickel-cobalt superalloy and its preparation method, wherein the chemical composition of the iron-nickel-cobalt superalloy is as follows (by mass percentage):

[0070] Cr: 8%, Mo: 2%, Ti: 2%, Re: 1%, Hf: 2.7%, Y: 3%, Nb: 0.5%; Ge: 0.2%; Ce: 0.1%, Fe: 20%, Co: 15%, Ni: balance, and unavoidable impurities such as C and P.

[0071] The preparation method of this iron-nickel-cobalt superalloy includes the following steps:

[0072] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0073] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0074] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 8 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0075] S4: Heat treatment process:

[0076] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0077] (2) Multi-stage time-sensitive processing:

[0078] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0079] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0080] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0081] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling. Example

[0082] This embodiment discloses an iron-nickel-cobalt superalloy and its preparation method, wherein the chemical composition of the iron-nickel-cobalt superalloy is as follows (by mass percentage):

[0083] Cr: 7%, Mo: 1.5%, Ti: 1.5%, Re: 0.75%, Hf: 3%, Y: 2.1%, Nb: 0.4%; Ge: 0.15%; Ce: 0.07%, Fe: 17%, Co: 12%, Ni: balance, and unavoidable impurities such as C and P.

[0084] The preparation method of this iron-nickel-cobalt superalloy includes the following steps:

[0085] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0086] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0087] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0088] S4: Heat treatment process:

[0089] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0090] (2) Multi-stage time-sensitive processing:

[0091] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0092] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0093] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0094] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0095] Comparative Example 1

[0096] Comparative Example 1 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0097] Cr: 6%, Mo: 1%, Ti: 1%, Hf: 2.5%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0098] The preparation method of this alloy includes the following steps:

[0099] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0100] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0101] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0102] S4: Heat treatment process:

[0103] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0104] (2) Multi-stage time-sensitive processing:

[0105] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0106] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0107] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0108] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0109] Comparative Example 2

[0110] Comparative Example 2 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0111] Cr: 6%, Mo: 1%, Ti: 1%, Re: 0.5%, Nb: 0.3%, Ge: 0.1%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0112] The preparation method of this alloy includes the following steps:

[0113] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0114] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0115] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0116] S4: Heat treatment process:

[0117] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0118] (2) Multi-stage time-sensitive processing:

[0119] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0120] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0121] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0122] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0123] Comparative Example 3

[0124] Comparative Example 3 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0125] Cr: 6%, Mo: 1%, Re: 0.5%, Hf: 2.5%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0126] The preparation method of this alloy includes the following steps:

[0127] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0128] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0129] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0130] S4: Heat treatment process:

[0131] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0132] (2) Multi-stage time-sensitive processing:

[0133] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0134] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0135] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0136] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0137] Comparative Example 4

[0138] Comparative Example 4 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0139] Cr: 6%, Mo: 1%, Re: 0.5%, Hf: 2.5%, Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0140] The preparation method of this alloy includes the following steps:

[0141] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0142] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0143] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0144] S4: Heat treatment process:

[0145] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0146] (2) Multi-stage time-sensitive processing:

[0147] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0148] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0149] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0150] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0151] Comparative Example 5

[0152] Comparative Example 5 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0153] Cr: 6%, Mo: 1%, Ti: 1%, Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0154] The preparation method of this alloy includes the following steps:

[0155] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0156] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0157] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0158] S4: Heat treatment process:

[0159] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0160] (2) Multi-stage time-sensitive processing:

[0161] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0162] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0163] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0164] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0165] Comparative Example 6

[0166] Comparative Example 6 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0167] Cr: 6%, Mo: 1%, Ti: 1%, Re: 0.5%, Hf: 2.5%, Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0168] The preparation method of this alloy includes the following steps:

[0169] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0170] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0171] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0172] S4: Heat treatment process:

[0173] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0174] (2) Multi-stage time-sensitive processing:

[0175] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0176] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0177] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0178] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0179] Comparative Example 7

[0180] Comparative Example 7 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0181] Cr: 6%, Mo: 1%, Ti: 1%, Hf: 2.5%, Nb: 0.3%, Ge: 0.1%; Y: 1%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0182] The preparation method of this alloy includes the following steps:

[0183] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0184] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0185] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0186] S4: Heat treatment process:

[0187] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0188] (2) Multi-stage time-sensitive processing:

[0189] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0190] Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h.

[0191] Three aging processes: The material is reheated to 650℃ and held for 8 hours;

[0192] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0193] Comparative Example 8

[0194] Comparative Example 8 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0195] Cr: 6%, Mo: 1%, Ti: 1%, Re: 0.5%, Hf: 2.5%, Y: 1%, Nb: 0.3%; Ge: 0.1%; Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0196] The preparation method of this iron-nickel-cobalt superalloy includes the following steps:

[0197] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0198] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0199] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0200] S4: Heat treatment process:

[0201] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0202] (2) Secondary aging process:

[0203] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0204] Secondary aging: The material is reheated to 650℃ and held for 8 hours;

[0205] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0206] Comparative Example 9

[0207] Comparative Example 9 discloses an alloy and its preparation method, wherein the chemical composition of the alloy, by mass percentage, is as follows:

[0208] Cr: 6%, Mo: 1%, Ti: 1%, Re: 0.5%, Hf: 2.5%, Y: 1%, Nb: 0.3%; Ge: 0.1%; Ce: 0.05%, Fe: 14%, Co: 10%, Ni: balance, and unavoidable impurities such as C and P.

[0209] The preparation method of this iron-nickel-cobalt superalloy includes the following steps:

[0210] S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2 hours.

[0211] S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2A / cm², the melting temperature is set at 1500℃, and the remelting process lasts for 3 hours.

[0212] S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 7 hours, and then switching to 1℃ / min until the temperature drops to room temperature;

[0213] S4: Heat treatment process:

[0214] (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water;

[0215] (2) Time-sensitive processing:

[0216] One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool;

[0217] S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

[0218] Detection methods

[0219] 1. The static oxidation behavior of the samples at 800℃ was tested according to HB5228-2000. The oxidation status of the samples was detected by the weight gain method. Three parallel samples were taken from each group, and the average value was calculated as the average oxidation weight gain rate.

[0220] (K, g·m) -2 ·h -1 The final test results are shown in Table 1.

[0221] Sample at 800℃ Example 1 0.019 Example 2 0.017 Example 3 0.015 Comparative Example 1 0.057 Comparative Example 2 0.043 Comparative Example 3 0.056 Comparative Example 4 0.042 Comparative Example 5 0.045 Comparative Example 6 0.033 Comparative Example 7 0.031 Comparative Example 8 0.028 Comparative Example 9 0.027

[0222] 2. The high-temperature tensile properties of the samples after being kept at 800℃ for 24 hours were tested according to GB / T4338-2006. Three parallel samples were taken from each group of samples and their average value was calculated. The final test results are shown in Table 2.

[0223] Table 2

[0224]

[0225] The test results above show that the oxidation weight gain rate of the alloy of the present invention is significantly reduced under high temperature conditions, indicating that its resistance to high temperature oxidation is significantly improved. Secondly, the tensile strength and yield strength at high temperature are improved to a certain extent. Furthermore, the data on elongation and reduction of area show that the creep resistance and high temperature stability of the alloy are greatly improved.

[0226] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature iron-nickel-cobalt alloy, characterized in that, The composition of the high-temperature alloy by mass percentage is as follows: Cr: 6%-8%, Mo: 1%-2%, Ti: 1%-2%, Re: 0.5%-1%, Hf: 2.5%-3%, Y: 1%-3%, Nb: 0.3-0.5%; Ge: 0.1-0.2%; Ce: 0.05%-0.1%, Fe: 14%-20%, Co: 10%-15%, Ni: balance, and unavoidable impurities such as C and P.

2. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The niobium content in the high-temperature alloy ranges from 0.4% to 0.45%.

3. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The chromium content in the high-temperature alloy ranges from 6.7% to 7.3%.

4. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The molybdenum content in the high-temperature alloy ranges from 1.2% to 1.8%.

5. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The titanium content in the high-temperature alloy ranges from 1.3% to 1.7%.

6. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The rhenium content in the high-temperature alloy ranges from 0.7% to 0.8%.

7. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The hafnium content in the high-temperature alloy ranges from 2.6% to 2.7%.

8. The iron-nickel-cobalt high-temperature alloy according to claim 1, characterized in that: The germanium content in the high-temperature alloy ranges from 0.1% to 0.16%.

9. The iron-nickel-cobalt high-temperature alloy according to claim 3, characterized in that: The yttrium content in the high-temperature alloy ranges from 1.7% to 2.3%.

10. A method for preparing an iron-nickel-cobalt superalloy according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Vacuum induction melting: The raw materials are melted under vacuum conditions, the melting temperature is controlled at 1600-1650℃, the melt temperature is kept stable, and the mixture is stirred evenly. The melting time is 2-3 hours. The nickel and iron raw materials are particles with a porous structure. S2: Electroslag remelting: Using electroslag remelting technology, the current density is controlled at 2-3A / cm², the melting temperature is set at 1500-1550℃, and the remelting process lasts for 3-4 hours. S3: Ingot cooling: A staged cooling method is adopted, first controlling the cooling at 2℃ / min for 6-8 hours, and then switching to 1℃ / min until the temperature drops to room temperature; S4: Heat treatment process: (1) Solution treatment: Heat to 1150℃, hold for 2 hours, and then quench in water; (2) Multi-stage time-sensitive processing: One-time aging: Heat to 750℃, hold for 16 hours, slowly cool to 500℃ at 10℃ / h, then air cool; Secondary aging: The material is reheated to 700℃ and held for 10 hours, then slowly cooled to 600℃ at a rate of 10℃ / h and held for 4 hours, and then slowly cooled to 500℃ at a rate of 10℃ / h. Three aging processes: The material is reheated to 650℃ and held for 8 hours; S5: Hot isostatic pressing: The temperature is controlled at 1200℃, the pressure is controlled at 100MPa, the static pressure time is controlled at 3 hours, and the cooling method is slow cooling with the furnace to 500℃ followed by air cooling.

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