CN117965962A - Low-expansion nickel-based superalloy, and preparation method and application thereof - Google Patents
Low-expansion nickel-based superalloy, and preparation method and application thereof Download PDFInfo
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 229910000601 superalloy Inorganic materials 0.000 title claims abstract description 42
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 24
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- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 5
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 4
- 238000001556 precipitation Methods 0.000 claims description 28
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- 238000005496 tempering Methods 0.000 claims 2
- 229910052742 iron Inorganic materials 0.000 claims 1
- 238000005728 strengthening Methods 0.000 abstract description 16
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- 229910001566 austenite Inorganic materials 0.000 abstract 1
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- YIWGJFPJRAEKMK-UHFFFAOYSA-N 1-(2H-benzotriazol-5-yl)-3-methyl-8-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carbonyl]-1,3,8-triazaspiro[4.5]decane-2,4-dione Chemical compound CN1C(=O)N(c2ccc3n[nH]nc3c2)C2(CCN(CC2)C(=O)c2cnc(NCc3cccc(OC(F)(F)F)c3)nc2)C1=O YIWGJFPJRAEKMK-UHFFFAOYSA-N 0.000 description 2
- 229910020630 Co Ni Inorganic materials 0.000 description 2
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Abstract
The invention relates to a low-expansion nickel-based superalloy, a preparation method and application thereof, wherein the low-expansion nickel-based superalloy comprises ：Fe：6～10％,Cr：12～20％,Mo：6～12％,W：0.2～0.8％,Ti：1.8～2.4％,Al：1.1～1.7％,C：0.02～0.08％,B：0.001～0.005％,Zr：0.01～0.05％,Co：1.7～2.3％, percent of Ni by mass. The mass fraction of Ti and Al satisfies: 1.4 < Ti/Al < 1.8. The alloy consists of an austenite matrix (gamma phase), an intragranular strengthening phase Ni 3 (Al, ti) (gamma' phase) and a grain boundary strengthening phase M 23C6. The alloy has the advantages of low thermal expansion coefficient, excellent high-temperature strength and toughness and good tissue and performance stability, and can be used for parts such as high-parameter ultra-supercritical power station steam turbine rotors, bolts, blades, valves and the like, aero-engine casings, sealing rings and the like.
Description
Technical Field
The invention belongs to the technical field of high-temperature alloys, and particularly relates to a low-expansion nickel-based high-temperature alloy, and a preparation method and application thereof.
Background
High temperature structural materials, represented by high temperature alloys and intermetallic compounds, are critical materials in the fabrication of hot side components. Because the structure and the working condition of the material are different in high-temperature service, the material has the service life under the specific service working condition for guaranteeing the structure, and the requirements on the comprehensive performance of the used material are also provided for the main performance. For example, superalloy tubing for reheaters/superheaters in ultra supercritical utility boilers is mainly required to have excellent high temperature durability and oxidation corrosion resistance; the high-temperature alloy for the container material of the molten fluoride salt in the fourth-generation nuclear reactor-thorium-based molten salt reactor mainly needs to have good oxidation resistance to the hot fluoride salt; high temperature alloys for aircraft engine combustion chambers are mainly required to have excellent cold and hot fatigue resistance. Aiming at structural components with approximately constant size in a certain high-temperature environment, such as a high-parameter ultra-supercritical power station turbine rotor, bolts, blades, valves, an aeroengine casing, a sealing ring and the like, the structural components are required to have lower thermal expansion coefficients besides the requirements on the performances of strength, oxidation resistance, corrosion resistance and the like, so that the dimensional change and the internal stress of the components are ensured to be as small as possible during service.
Various low expansion alloys capable of meeting the requirements at different temperatures are developed mainly through alloy composition optimization. Low expansion alloys such as Inco1oy903 and Inco1oy907 which do not contain Cr element have been developed abroad in seventies of the last century, resulting in poor oxidation resistance. Subsequently, low expansion alloys such as Inconel783, thermo-span and the like containing Cr element were developed so that the oxidation resistance thereof was significantly improved, but the addition of Cr resulted in a significant increase in the thermal expansion coefficient of the alloy with an increase in temperature. And the high alloying makes the alloy poorer in formability and structural stability. Therefore, in order to meet the requirements of the modern aviation and energy fields, the development of the alloy with lower high-temperature thermal expansion coefficient and higher comprehensive performance has important scientific significance and application value.
Disclosure of Invention
Therefore, the invention aims to overcome the defect of poor comprehensive performance of the alloy with low high-temperature thermal expansion coefficient in the prior art, thereby providing the low-expansion nickel-based superalloy, and the preparation method and the application thereof. The low-expansion nickel-based superalloy has low thermal expansion coefficient, excellent high-temperature strength and toughness and good tissue and performance stability, and can be used for parts such as high-parameter ultra-supercritical power station steam turbine rotors, bolts, blades, valves and the like, aeroengine casings, sealing rings and the like.
For this purpose, the invention provides the following technical scheme.
In a first aspect, the invention provides a low-expansion nickel-based superalloy, which comprises ：Fe：6～10％,Cr：12～20％,Mo：6～12％,W：0.2～0.8％,Ti：1.8～2.4％,Al：1.1～1.7％,C：0.02～0.08％,B：0.001～0.005％,Zr：0.01～0.05％,Co：1.7～2.3％, mass percent of Ni as the rest, wherein the mass fraction of Ti and Al is as follows: 1.4 < Ti/Al < 1.8.
Further, the mass percentage content of Fe is 7-9%; the mass percentage content of Co is 1.8-2.2%.
Further, the mass fraction of Ti and Al satisfies the following conditions: ti/Al is more than or equal to 1.5 and less than or equal to 1.7.
Further, at least one of the following conditions is satisfied:
(1) The mass percentage content of Cr is 14-18%;
(2) The mass percentage content of Mo is 8-10%;
(3) The weight percentage content of W is 0.4-0.6%;
(4) The mass percentage content of Ti is 2.0-2.2%;
(5) The mass percentage content of Al is 1.3-1.5%;
(6) The mass percentage content of C is 0.04-0.06%;
(7) The mass percentage content of the B is 0.002-0.004%;
(8) The mass percentage content of Zr is 0.02-0.04%.
In a second aspect, the invention provides a method for preparing a low expansion nickel-base superalloy, comprising the steps of:
step 1: smelting raw materials in vacuum, casting into alloy ingots, homogenizing the alloy ingots at 1150-1200 ℃ for 10-20 hours, and then air-cooling to room temperature;
step 2: rolling the homogenized alloy ingot at 150-200 ℃ above the gamma' -phase precipitation temperature, wherein the deformation of each pass is 10-20%, the deformation of the last pass is more than 20%, and the total deformation is 40-60%;
Step 3: carrying out solution treatment on the rolled alloy for 1-2 hours at 140-180 ℃ above the gamma '-phase precipitation temperature, and then carrying out solution treatment for 1.5-2.5 hours at 80-100 ℃ above the gamma' -phase precipitation temperature;
Step 4: and (3) carrying out time-efficient treatment on the alloy subjected to solution treatment for 10-14 hours at the temperature of 280-320 ℃ below the precipitation temperature of the gamma 'phase, and then carrying out time-efficient treatment on the alloy subjected to solution treatment for 2-6 hours at the temperature of 100-140 ℃ below the precipitation temperature of the gamma' phase, so as to obtain the low-expansion nickel-based superalloy.
In step 2, furnace return heat preservation is performed after each pass of rolling is completed, and then the next pass of rolling is performed.
Further, in the step 2, the temperature of heat preservation of each time of furnace returning is consistent with the rolling temperature, and the heat preservation time of the furnace returning is 10-20min.
Further, the average grain size of the prepared low-expansion nickel-based superalloy is 60-100 mu M, the size of gamma' phase in the crystal is 20-40nm, and M 23C6 type carbide is continuously distributed on the grain boundary; the average linear expansion coefficient of the alloy between 20 ℃ and 650 ℃ is less than 15 multiplied by 10 -6/DEG C; the yield strength of the alloy at 650 ℃ is not lower than 600MPa, and the elongation after fracture is not lower than 35%; the alloy has no precipitation of harmful phases after 2300h of heat exposure at 650 ℃.
In a third aspect, the invention provides the use of a low expansion nickel-base superalloy or a low expansion nickel-base superalloy produced according to the method in thermal power plants and aircraft engines.
The technical scheme of the invention has the following advantages:
1. The low-expansion nickel-based superalloy provided by the invention comprises ：Fe：6～10％,Cr：12～20％,Mo：6～12％,W：0.2～0.8％,Ti：1.8～2.4％,Al：1.1～1.7％,C：0.02～0.08％,B：0.001～0.005％,Zr：0.01～0.05％,Co：1.7～2.3％, mass percent of Ni, and the balance of Ni, wherein Ti/Al is more than 1.4 and less than 1.8.
The low-expansion nickel-based superalloy provided by the invention is based on the alloy design concept of precipitation strengthening, solid solution strengthening and grain boundary strengthening.
As the main elements of the precipitation strengthening phase Ni 3 (Al, ti) (gamma '), a proper amount of Ti and Al ensure the volume fraction of the gamma ' strengthening phase in the crystal, and too low total amount of Ti and Al elements can reduce the volume fraction of the gamma ' strengthening phase in the crystal, so that the strength of the alloy can not be ensured, and when the total amount is too high, the thermal expansion coefficient can be increased. At the same time, the relatively high Ti/A1 ratio increases the phase inversion domain boundary energy, thereby increasing the strength and avoiding the precipitation of harmful phases. However, when the Ti/A1 ratio is too high, the stability of the gamma' -phase at high temperature is lowered, and the high-temperature strength and hot workability of the alloy are lowered. When the Ti/A1 ratio is too low, the tendency of the precipitation of a detrimental phase in the crystal increases, which seriously impairs the overall properties of the alloy. Therefore, the Ti content should be controlled to be 1.8-2.4%, the Al content should be controlled to be 1.1-1.7%, and the Ti/Al ratio should be controlled to be 1.4-1.8%.
Cr is used as solid solution element to strengthen the alloy, and simultaneously, the Cr and Al are used together to improve the oxidation resistance and corrosion resistance of the alloy, and meanwhile, the formation of harmful phases is avoided. The oxidation resistance of the alloy cannot be guaranteed due to the excessively low Cr content. The Cr content is too high, so that the thermal expansion coefficient of the alloy can be obviously improved, the precipitation of harmful phases is promoted, and the mechanical property of the alloy is reduced. Therefore, the Cr content of the present invention is controlled to 12-20%.
As a solid solution element, W, mo has a great promotion effect on the high-temperature performance of the alloy, and can reduce the thermal expansion coefficient of the alloy. However, too high a W content increases the segregation degree during alloy melting, and consequently reduces the hot workability of the alloy. The excessive Mo content is easy to cause pitting corrosion, and can form volatile oxide to damage the oxidation resistance of the alloy. Too low a W, mo content reduces the solution strengthening effect and increases the coefficient of thermal expansion of the alloy. Therefore, the W content is controlled to be 0.2-0.8%, and the Mo content is controlled to be 6-12%.
The proper amount of Fe is mainly used for replacing Ni. Because the cost of Fe is relatively low, the cost performance of the alloy can be obviously improved by a proper amount of Fe, and the hot workability of the alloy can be obviously improved by Fe. However, too high a Fe content reduces the corrosion resistance of the alloy, is unfavorable for precipitation of the gamma' -strengthening phase, and reduces the structural stability and high-temperature strength of the alloy. Therefore, the Fe content of the present invention should be controlled to 6-10%.
For Ni 3 (Al, ti) (γ ') phase strengthened superalloys, the better the γ ' phase stability of the alloy, the smaller the coefficient of thermal expansion of the alloy, and therefore, the addition of a γ ' phase stabilizing element is also beneficial to reducing the coefficient of thermal expansion of the alloy. The proper amount of Co can reduce the steady-state creep rate and increase the number of gamma 'strengthening phases so as to improve the strength, and further ensure that the gamma' strengthening phases have good thermal stability in a service temperature range. Meanwhile, the Co, W and Mo composite addition ensures that the alloy has a lower thermal expansion coefficient. The Co content of the invention is controlled to be 1.7-2.3%, and the cost can be effectively controlled while the beneficial effects are achieved.
A proper amount of C element forms an M 23C6 carbide reinforced grain boundary at the grain boundary, and a proper amount of B, zr element is converged to the grain boundary, so that the grain boundary defect is reduced, the binding force of the grain boundary is improved, and the diffusion rate of the grain boundary is reduced, so that the grain boundary is further reinforced; C. the synergistic effect of B, zr elements ensures excellent high-temperature strength of grain boundaries. However, when the C content is too high, the mass fraction of carbides (e.g., MC and M 23C6 type carbides) increases, the morphology, size and distribution are difficult to control, and the occupancy of alloy strengthening elements (e.g., cr, ti) results in a reduced intra-crystalline strengthening effect. Therefore, the C content of the invention should be controlled between 0.02 and 0.08 percent. When the B content is too high, boride eutectic is formed, which impairs the technological properties and mechanical properties of the alloy. Therefore, the B content of the present invention should be controlled to 0.001 to 0.005%. When the Zr content is too high, coarsening of gamma' phase in the service process can be accelerated, so that the mechanical property is lost. Therefore, the Zr content of the present invention should be controlled to be 0.01 to 0.05%.
The low-expansion nickel-based superalloy designed by the invention contains low content of Co and proper amount of Fe, and has a proper Ti/Al ratio, a low thermal expansion coefficient, excellent high-temperature strength and toughness, hot workability, oxidation resistance and good tissue and performance stability while ensuring low cost of the alloy.
The average grain size of the low-expansion nickel-based superalloy prepared by the invention is 60-100 mu M, the size of gamma' phase in the crystal is 20-40nm, and M 23C6 carbide which is continuously distributed on the grain boundary is arranged; the average linear expansion coefficient of the alloy between 20 ℃ and 650 ℃ is less than 15 multiplied by 10 -6/DEG C; the yield strength of the alloy at 650 ℃ is not lower than 600MPa, and the elongation after fracture is not lower than 30%; the alloy has no precipitation of harmful phases after 2300h of heat exposure at 650 ℃.
2. The preparation method of the low-expansion nickel-based superalloy provided by the invention firstly adopts proper homogenization temperature and time, and ensures economy while obviously improving the tissue uniformity. And a simple rolling processing mode is adopted, rolling is carried out at 150-200 ℃ above the precipitation temperature of the gamma '-phase, so that the complete dissolution of the gamma' -phase of the strengthening phase is ensured, the deformation resistance is effectively reduced, and the driving force of grain growth is controlled. Through matching reasonable rolling deformation and furnace returning time, coarse grains are crushed and recrystallized to be refined, and meanwhile, the coarse grains do not grow obviously, and the alloy is ensured to have higher energy storage and finer grain size by adopting large deformation processing in the last pass, so that the grain size is effectively regulated and controlled. Then, adopting graded solid solution treatment, firstly carrying out solid solution treatment on the alloy after thermal deformation for 1-2 hours at 140-180 ℃ above the gamma 'phase precipitation temperature so as to further control the grain size to meet the use requirement, and then carrying out solid solution treatment for 1.5-2.5 hours at 80-100 ℃ above the gamma' phase precipitation temperature so as to further control the size and distribution of carbide, thereby further improving the durability. And finally, adopting graded aging treatment, firstly carrying out time-efficient treatment on the alloy subjected to solution treatment for 10-14 hours at the temperature of 280-320 ℃ below the precipitation temperature of the gamma 'phase so as to control the nucleation of the gamma' phase, then carrying out time-efficient treatment for 2-6 hours at the temperature of 100-140 ℃ below the precipitation temperature of the gamma 'phase, and further controlling the particle diameter and volume fraction of the gamma' phase. The alloy has low thermal expansion coefficient at 600-700 ℃, excellent high-temperature strength and toughness and good structure and performance stability, and can be suitable for manufacturing parts such as high-parameter ultra-supercritical power station turbine bolts and blades, aeroengine cases, sealing rings and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a grain characterization of the low expansion nickel-base superalloy prepared in example 1;
FIG. 2 is a grain boundary M 23C6 morphology of the low-expansion nickel-base superalloy prepared in example 1;
FIG. 3 is an intra-crystalline gamma prime phase morphology of the low expansion nickel-base superalloy prepared in example 1;
FIG. 4 is a microstructure morphology of the low expansion nickel-base superalloy prepared in example 1 after 2300h of thermal exposure at 650 ℃.
FIG. 5 is a texture morphology of the low expansion nickel-base superalloy prepared in comparative example 2 after 2300h of heat exposure at 650 ℃.
Detailed Description
The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the invention, any product which is the same or similar to the present invention, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present invention.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
The preparation method of the low-expansion nickel-based superalloy comprises the following steps:
step 1: the raw materials are smelted and cast into alloy ingots under vacuum, and then the alloy ingots are homogenized for 10-20 hours at 1150-1200 ℃ and then air-cooled to room temperature.
TABLE 1 chemical composition (wt.%)
| Fe | Cr | Mo | W | Ti | Al | C | B | Zr | Co | Ni | |
| Example 1 | 9 | 16 | 9 | 0.5 | 2.1 | 1.4 | 0.05 | 0.003 | 0.02 | 2.0 | Bal. |
| Example 2 | 7 | 14 | 8 | 0.4 | 2.4 | 1.6 | 0.06 | 0.004 | 0.03 | 2.1 | Bal. |
| Example 3 | 8 | 17 | 10 | 0.6 | 2.2 | 1.3 | 0.07 | 0.002 | 0.02 | 1.9 | Bal. |
| Example 4 | 7 | 13 | 11 | 0.5 | 2.3 | 1.5 | 0.04 | 0.005 | 0.04 | 2.2 | Bal. |
TABLE 2 homogenization conditions
| Temperature (. Degree. C.) | Time (h) | |
| Example 1 | 1150 | 20 |
| Example 2 | 1200 | 10 |
| Example 3 | 1170 | 16 |
| Example 4 | 1180 | 14 |
And step 2, rolling the homogenized alloy ingot at 150-200 ℃ above the gamma' -precipitation temperature, wherein the deformation of each pass is 10-20%, the deformation of the last pass is more than 20%, the total deformation is 40-60%, and the furnace returning and heat preservation are carried out for 10-20min after the hot rolling of each pass is completed.
TABLE 3 Hot Rolling parameters and Heat preservation conditions
The alloys of examples 1-4 had good hot workability and no defects such as cracks were observed during hot working.
Step 3, carrying out solution treatment on the alloy after hot rolling for 1-2 hours at 140-180 ℃ above the precipitation temperature of the gamma 'phase, and then carrying out solution treatment for 1.5-2.5 hours at 80-100 ℃ above the precipitation temperature of the gamma' phase;
step 4: and (3) carrying out time-efficient treatment on the alloy subjected to solid solution at the temperature of 280-320 ℃ below the gamma '-phase precipitation temperature for 10-14 hours, and then carrying out time-efficient treatment at the temperature of 100-140 ℃ below the gamma' -phase precipitation temperature for 2-6 hours to obtain the low-expansion nickel-based superalloy.
TABLE 4 solution treatment conditions
TABLE 5 aging conditions
The low expansion nickel-base superalloy prepared by the invention has an average grain size of 60-100 μm, and typical grain structure characteristics are shown in figure 1. The grain boundary is provided with M 23C6 type carbide which is continuously distributed, and the morphology of the grain boundary M 23C6 is shown in figure 2. The size of the gamma 'phase in the crystal is 20-40nm, and the morphology of the gamma' strengthening phase in the crystal is shown in figure 3.
TABLE 6 average grain size
| Average grain size (μm) | |
| Example 1 | 75 |
| Example 2 | 93 |
| Example 3 | 72 |
| Example 4 | 80 |
Comparative example 1
This comparative example was substantially the same as example 1 except that the comparative example did not contain Co element and the composition is shown in Table 7.
Comparative example 2
This comparative example was substantially the same as example 1 except that Ti/Al was 1.2 and the composition thereof was as shown in Table 7.
Comparative example 3
This comparative example was substantially the same as example 1 except that the Fe content was higher in this comparative example and the composition was as shown in Table 7.
Table 7 chemical Components (mass%) of comparative example
| Fe | Cr | Mo | W | Ti | Al | C | B | Zr | Co | Ni | Nb | |
| Comparative example 1 | 9 | 16 | 9 | 0.5 | 2.1 | 1.4 | 0.05 | 0.003 | 0.02 | 0 | Bal. | -- |
| Comparative example 2 | 9 | 16 | 9 | 0.5 | 2.1 | 1.75 | 0.05 | 0.003 | 0.02 | 2.0 | Bal. | |
| Comparative example 3 | 35 | 16 | 9 | 0.5 | 2.1 | 1.4 | 0.05 | 0.003 | 0.02 | 2.0 | Bal. |
Test examples
Tensile property test: the tensile strength and yield strength of the alloys were measured at 650 c, respectively, and the measurement results are shown in table 8.
Table 8 alloy properties at 650℃
From examples 1 to 4, it is understood that the alloy of the present invention has excellent toughness while having excellent high-temperature strength. Meanwhile, the average linear expansion coefficient of the alloy is smaller than 15 multiplied by 10 -6/DEG C at 20-650 ℃.
As is clear from comparison of example 1 and comparative examples 1 and 3, too high a content of Fe or too low a content of Co decreases the strength of the alloy and increases the thermal expansion coefficient at 20 to 650 ℃.
Long-term organization and performance stability: when the sum of Ti and Al does not change much, the Ti/Al ratio has no significant effect on the alloy short-time strength, but has significant effect on the long-time structure stability of the alloy. FIG. 4 is a microstructure morphology of the low expansion nickel-base superalloy prepared in example 1 after 2300h of thermal exposure at 650 ℃. It can be seen that after 2300h of heat exposure, no harmful phase is precipitated in the crystal, and M 23C6 type carbide at the crystal boundary and gamma' phase in the crystal are stable. FIG. 5 is a microstructure morphology of the low expansion nickel-base superalloy prepared in comparative example 2 after 2300h of heat exposure at 650 ℃. It can be seen that at a Ti/Al of 1.2, needle-like detrimental phases are precipitated in the crystal, which seriously impair the overall properties of the alloy.
Table 9 shows the 650 ℃ tensile properties of example 1 after 650 ℃ heat exposure, and shows that the alloy strength increases after long heat exposure, the plasticity slightly decreases and still has excellent toughness.
TABLE 9 tensile properties at 650℃after heat exposure at 650 DEG C
Durability performance: table 10 shows the durability, and the alloy of the present invention is excellent in durability.
Table 10 durability performance
In conclusion, the low-expansion nickel-based superalloy has excellent high-temperature strength and toughness, hot workability and oxidation resistance, and good structure and performance stability, and can be applied to manufacturing structural components such as high-parameter ultra-supercritical power station steam turbine rotors, bolts, blades, valves and the like, aeroengine casings, sealing rings and the like.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (9)
1. The low-expansion nickel-base superalloy is characterized by comprising Fe：6～10％,Cr：12～20％,Mo：6～12％,W：0.2～0.8％,Ti：1.8～2.4％,Al：1.1～1.7％,C：0.02～0.08％,B：0.001～0.005％,Zr：0.01～0.05％,Co：1.7～2.3％, mass percent of Ni, wherein the balance is Ni, and 1.4 is less than Ti/Al and less than 1.8.
2. The low expansion nickel-base superalloy according to claim 1, wherein the mass percentage of Fe is 7-9%; and/or
The mass percentage content of Co is 1.8-2.2%.
3. The low expansion nickel-base superalloy of claim 1, wherein 1.5-1.7 Ti/Al.
4. A nickel-base superalloy according to any of the claims 1-3, wherein at least one of the following conditions is fulfilled:
(1) The mass percentage content of Cr is 14-18%;
(2) The mass percentage content of Mo is 8-10%;
(3) The weight percentage content of W is 0.4-0.6%;
(4) The mass percentage content of Ti is 2.0-2.2%;
(5) The mass percentage content of Al is 1.3-1.5%;
(6) The mass percentage content of C is 0.04-0.06%;
(7) The mass percentage content of the B is 0.002-0.004%;
(8) The mass percentage content of Zr is 0.02-0.04%.
5. A method of preparing a low expansion nickel base superalloy as claimed in any of claims 1 to 4, comprising the steps of:
step 1: smelting raw materials in vacuum, casting into alloy ingots, homogenizing the alloy ingots at 1150-1200 ℃ for 10-20 hours, and then air-cooling to room temperature;
Step 2: rolling the homogenized alloy ingot at 150-200 ℃ above the gamma' -phase precipitation temperature, wherein the deformation of each pass is 10-20%, the deformation of the last pass is more than 20%, and the total deformation is 40-60%;
Step 3: carrying out solution treatment on the rolled alloy for 1-2 hours at 140-180 ℃ above the gamma '-phase precipitation temperature, and then carrying out solution treatment for 1.5-2.5 hours at 80-100 ℃ above the gamma' -phase precipitation temperature;
step 4: and (3) performing an effective treatment on the alloy subjected to the solution treatment at the temperature of 280-320 ℃ below the gamma '-phase precipitation temperature for 10-14 hours, and then performing an effective treatment at the temperature of 100-140 ℃ below the gamma' -phase precipitation temperature for 2-6 hours to obtain the low-expansion nickel-based superalloy.
6. The method of producing a low expansion nickel-base superalloy according to claim 5, wherein in step 2, the next pass is performed after the completion of each pass of rolling by holding the temperature in a furnace.
7. The method for producing a low expansion nickel-base superalloy according to claim 6, wherein in step 2, the temperature of each heat preservation by tempering is the same as the rolling temperature, and the tempering time is 10-20min.
8. The method for producing a low expansion nickel-base superalloy according to any of claims 5 to 7, wherein the low expansion nickel-base superalloy is produced with an average grain size of 60 to 100 μm, an intra-grain gamma' -phase size of 20 to 40nm, and a continuous distribution of M 23C6 -type carbide on grain boundaries.
9. Use of a low expansion nickel-base superalloy according to any of claims 1 to 4 or a low expansion nickel-base superalloy produced according to the method of any of claims 5 to 8 in a high parameter thermal power plant or an aeroengine.
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