Low-cost hot-corrosion-resistant high-strength single-crystal high-temperature alloy as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of alloy materials, and particularly relates to a low-cost hot-corrosion-resistant high-strength single-crystal high-temperature alloy and a preparation method and application thereof. The invention provides a single-crystal high-temperature alloy with low cost, hot corrosion resistance and high strength. The single-crystal high-temperature alloy is prepared from the following element components in percentage by mass: 11 to 13 percent of Cr, 8 to 11 percent of Co, 0 to 0.5 percent of Mo, 2 to 5 percent of W, 4 to 6 percent of Ta, 3.2 to 4.2 percent of Al, 3.6 to 4.6 percent of Ti, 0 to 0.15 percent of C, 0.02 to 0.04 percent of Ce and the balance of Ni and inevitable impurities. Under the combined action of the elements, the alloy has excellent hot corrosion resistance and mechanical property. Meanwhile, by adding trace rare earth element cerium (Ce) and completely not using expensive rhenium (Re) element, the comprehensive performance of the alloy is improved, and the production cost of the alloy is remarkably reduced.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, specifically relating to a low-cost, heat-corrosion-resistant, high-strength single-crystal high-temperature alloy, its preparation method, and its application. Background Technology

[0002] With the technological advancements in fields such as ground-based gas turbines, marine gas turbines, and long-life aero-engines for near-shore applications, higher demands are being placed on the comprehensive performance of high-temperature alloy materials used in turbine blades. Ideal materials for turbine blade fabrication must possess excellent heat corrosion resistance, outstanding high-temperature structural stability, and high-temperature mechanical properties that significantly surpass those of first-generation single-crystal high-temperature alloys. However, the alloy composition design window for achieving these multiple high-performance objectives is extremely narrow, posing a severe challenge to the development of new materials.

[0003] Currently, while developed hot-corrosion resistant nickel-based single-crystal superalloys such as DD413 and DD8 possess good hot-corrosion resistance, their high-temperature strength still lags behind that of second-generation single-crystal superalloys. Furthermore, second-generation high-strength nickel-based single-crystal superalloys, represented by DD5 and DD6, contain 2-3% rhenium (Re), leading to significantly increased costs, and their hot-corrosion resistance and long-term structural stability are also insufficient.

[0004] Currently, single-crystal superalloys that can balance low cost, excellent resistance to hot corrosion, and high strength are still scarce. Summary of the Invention

[0005] In view of this, the present invention provides a low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy, its preparation method and application. The alloy provided by the present invention has both excellent hot-corrosion resistance and mechanical properties, and its preparation cost is low, so it can be widely used to prepare key hot-end components such as high-temperature turbine blades.

[0006] To address the aforementioned technical problems, this invention provides a low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy comprising the following elemental components by mass percentage: Cr: 11-13%, Co: 8-11%, Mo: 0-0.5%, W: 2-5%, Ta: 4-6%, Al: 3.2-4.2%, Ti: 3.6-4.6%, C: 0-0.15%, Ce: 0.02-0.04%, with the balance being Ni and unavoidable impurities.

[0007] Preferably, the elemental composition includes the following mass percentages: Cr: 12.1~12.8%, Co: 8.5~10.5%, Mo: 0.3~0.5%, W: 2.6~4.4%, Ta: 4.6~5.3%, Al: 3.5~4.0%, Ti: 3.9~4.1%, C: 0.05~0.09%, Ce: 0.02~0.03%, with the balance being Ni and unavoidable impurities.

[0008] Preferably, Ta / (W+2Mo) = 1~1.1, Nv ≤ 2.4.

[0009] This invention also provides a method for preparing the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy described in the above technical solution, comprising the following steps: The raw materials are mixed according to the element ratio and then melted and cast sequentially to obtain the master alloy ingot. The master alloy ingot was directionally solidified to obtain a single crystal sample. The single crystal sample was heat-treated to obtain the low-cost, high-strength, heat-corrosion-resistant single crystal high-temperature alloy.

[0010] Preferably, the remelting temperature during the directional solidification process is 1540~1560℃, and the pulling rate is 3.5~4.5mm / min.

[0011] Preferably, the heat treatment includes a solution treatment and an aging treatment performed sequentially; The solution treatment includes a first solution treatment and a second solution treatment performed sequentially. The timeliness processing includes a first timeliness processing and a second timeliness processing performed sequentially.

[0012] Preferably, the holding temperature for the first solution treatment is 1280~1300℃, the holding time is 1.5~2.5h, and the heating rate is 5~8℃ / min; The second solution treatment is held at a temperature of 1310~1320℃ for 5~7 hours, with a heating rate of 1.5~2.5℃ / min. The holding temperature for the first aging treatment is 1130~1150℃, the holding time is 3~5h, and the heating rate is 8~12℃ / min; The second aging treatment is held at a temperature of 860~880℃ for 18~22h, and the heating rate is 8~12℃ / min.

[0013] Preferably, the melting includes vacuum induction melting, wherein the temperature of the vacuum induction melting can be 1520~1540℃, the time is 25~35min, and the vacuum degree is below 3Pa.

[0014] Preferably, the raw materials for preparation include Ni, Cr, Co, Mo, W, Ta, Ti, Al, C and Al-8Ce master alloys.

[0015] The present invention also provides the application of the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy described in the above technical solution or the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy prepared by the preparation method described in the above technical solution in the preparation of high-temperature turbine blades.

[0016] This invention provides a low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy comprising the following elemental components by mass percentage: Cr: 11-13%, Co: 8-11%, Mo: 0-0.5%, W: 2-5%, Ta: 4-6%, Al: 3.2-4.2%, Ti: 3.6-4.6%, C: 0-0.15%, Ce: 0.02-0.04%, with the balance being Ni and unavoidable impurities. The combined effect of these elements gives the alloy excellent hot-corrosion resistance and mechanical properties. Furthermore, by adding trace amounts of the rare earth element cerium (Ce) and completely avoiding the use of expensive rhenium (Re), this invention improves the overall performance of the alloy and significantly reduces its production cost. Attached Figure Description

[0017] Figure 1 Larson-Miller curves for Example 2 and PWA1483 alloy; Figure 2 The high-temperature mechanical property curves of the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy prepared in Example 3 are shown. Figure 3 The hot corrosion performance curves are for the alloy of Example 5 and the PWA1483 alloy. Detailed Implementation

[0018] This invention provides a low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy comprising the following elemental components by mass percentage: Cr: 11-13%, Co: 8-11%, Mo: 0-0.5%, W: 2-5%, Ta: 4-6%, Al: 3.2-4.2%, Ti: 3.6-4.6%, C: 0-0.15%, Ce: 0.02-0.04%, with the balance being Ni and unavoidable impurities.

[0019] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention, by weight percentage, comprises 11-13% Cr, which can be 12.1-12.8% Cr; specifically, it can be 12.1%, 12.3%, 12.4%, 12.6%, or 12.7%. In this invention, the alloy's hot-corrosion resistance mainly depends on sufficient Cr content to form a protective oxide film, and requires the assistance of elements such as Al and Ta. If the Cr content is increased to above 16% (wt.%), the hot-corrosion resistance will be significantly improved, but the high-temperature mechanical properties will be reduced. Chromium (Cr) is crucial for forming a protective Cr2O3 oxide film and fixing sulfur, and is the core element for achieving hot-corrosion resistance. However, the solid solution strengthening effect of Cr is relatively weak, and its excessive content will limit the addition of key strengthening elements (such as W, Mo, and Ta) to prevent the induction of the TCP harmful phase, which would lead to a decrease in alloy strength. This invention, by precisely designing the Cr content, retains sufficient hot-corrosion resistance while leaving room for the addition of other strengthening elements, thereby ensuring the high strength of the alloy.

[0020] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention comprises 8-11% Co, specifically 8.5-10.5%, and can be 8.8%, 9.3%, 9.8%, 10.3%, or 10.5% by mass percentage. In this invention, cobalt (Co) is completely miscible with the nickel (Ni) matrix. Its addition effectively hinders the cross-slip of screw dislocations and reduces the stacking fault energy of the matrix, thus contributing to the strengthening effect. However, excessively high Co content has adverse effects: firstly, it lowers the initial melting temperature of the alloy, impairing its high-temperature load-bearing capacity; secondly, it promotes the precipitation of harmful topologically close-packed (TCP) phases, deteriorating mechanical properties. This invention controls the Co content within the range of 8-11% to ensure the overall performance of the alloy.

[0021] Based on mass percentage, the low-cost, heat-corrosion-resistant, high-strength single-crystal high-temperature alloy provided by this invention comprises 0~0.5% Mo, which can be 0.3~0.5%; specifically, it can be 0.3%, 0.4% or 0.5%.

[0022] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention comprises 2-5% W, which can be 2.6-4.4%; specifically, it can be 3.6%, 3.8%, 4.1%, 4.2%, or 4.3%. In this invention, tungsten (W) and molybdenum (Mo) are key solid solution strengthening elements, but their contents must be strictly controlled. This is because, on the one hand, W and Mo are the main elements that promote the precipitation of topologically close-packed (TCP) phases, which is extremely detrimental to the long-term microstructure stability of the alloy; on the other hand, in a high-temperature environment containing Na₂SO₄, they can trigger an acidic melting reaction, exacerbating the hot corrosion process. In particular, a high content of Mo leads to the formation of a large amount of volatile oxides, hindering the formation of a protective oxide film, thereby causing severe corrosion failure. Therefore, this invention limits the W content to 2-5% and controls the Mo content at a low level of 0-0.5% to achieve the best balance between solid solution strengthening, microstructure stability, and hot corrosion resistance.

[0023] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention comprises 4-6% Ta, which can be 4.6-5.3%; specifically, it can be 4.6%, 4.8%, 5.1%, or 5.3%. In this invention, the addition of tantalum (Ta) plays a crucial role in improving the overall performance of the alloy. Regarding hot corrosion resistance, Ta can inhibit the formation of liquid Na2(Mo,W)O4 and promote the formation of solid NaTaO3, thereby delaying the hot corrosion process. Simultaneously, Ta can partially replace Cr in fixing sulfur (S), significantly improving the alloy's hot corrosion resistance by promoting the formation of solid TaS2 and inhibiting the formation of liquid NiS5. In terms of microstructure control, this invention controls the Ta / (W+2Mo) ratio within the range of 1-1.1, ensuring that the γ' phase has excellent cubicity and strength after high-temperature aging, and maintaining the γ / γ' phase mismatch at a low level, thereby delaying the coarsening rate of the γ' phase during long-term service.

[0024] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention comprises 3.2-4.2% Al, which can be 3.5-4.0%; specifically, it can be 3.6%, 3.7%, or 3.9%. In this invention, aluminum (Al) is the most critical element for forming the precipitation-strengthening phase γ'-Ni3(Al, Ti), playing a decisive role in the high-temperature strength of the alloy and also contributing to improving its oxidation resistance. However, studies have confirmed that excessively high Al content weakens the alloy's protection against liquid Na2SO4 salts, which is detrimental to its hot-corrosion resistance.

[0025] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention, by mass percentage, comprises 3.6-4.6% Ti, which can be 3.9-4.1%; specifically, it can be 3.9%, 4%, or 4.1%. In this invention, titanium (Ti) is one of the key elements in the formation of the precipitation-strengthened γ' phase, playing a significant role in improving the high-temperature strength of the alloy. Its strengthening mechanism partly stems from Ti's ability to effectively increase the antiphase domain boundary energy of the γ' phase. Simultaneously, Ti also contributes positively to the alloy's resistance to hot corrosion. However, excessively high Ti content significantly increases the γ / γ' eutectic content of the alloy, deteriorates microstructure stability, and increases the difficulty of solution heat treatment and the risk of initial melting. To balance strength, corrosion resistance, and microstructure stability, this invention limits the Ti content to 3.6-4.6%.

[0026] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention, by mass percentage, comprises 0~0.15% C, which can be 0.05~0.09%; specifically, it can be 0.05%, 0.06%, 0.07%, or 0.09%. In this invention, the addition of carbon (C) can improve the casting process performance of the alloy to a certain extent and increase its defect tolerance. However, excessively high carbon content will form too many coarse carbides, which will adversely affect the high-temperature mechanical properties and hot-corrosion resistance of the alloy.

[0027] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention comprises 0.02~0.04% Ce, which can be 0.02~0.03%; specifically, 0.02% or 0.03%. In this invention, the addition of the rare earth element cerium (Ce) comprehensively enhances the overall performance of the alloy through a multi-dimensional mechanism. At the microstructure level, Ce purifies the melt through strong deoxidation and desulfurization, generating high-melting-point rare earth compounds; simultaneously, it refines and optimizes the size and distribution of the γ' strengthening phase, improves the mismatch between the γ / γ' phases, and effectively suppresses the dendritic segregation of elements such as W and Mo, thereby significantly reducing the precipitation tendency of the TCP harmful phase and improving the microstructure stability. In terms of interface behavior, the segregation of Ce at key locations such as phase boundaries strengthens the interface, hinders dislocation movement, and slows down element diffusion. In terms of surface stability, Ce promotes the formation of a denser and more adhesive α-Al2O3 protective film and blocks short-circuit diffusion channels within it, significantly improving the alloy's resistance to cyclic oxidation and hot corrosion. This invention significantly improves the creep strength and fatigue life of the alloy by introducing cerium; at the same time, in order to avoid the formation of coarse and brittle phases by excessive Ce, this invention strictly controls its content to 0.02~0.03%.

[0028] The low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy provided by this invention, by weight percentage, comprises the balance Ni and unavoidable impurities; the unavoidable impurities include S, N, O, P, Mn, Mg, Cu, Si, Sn, Zr, Pb, Bi, Te, and Se; by weight percentage, the content of the impurities can be S≤0.1%, N≤0.1%, O≤0.1%, P≤0.3%, Mn≤0.5%, Mg≤0.6%, Cu≤4%, Si≤5%, Sn≤0.1%, Zr≤0.65%, Pb≤0.02%, Bi≤0.002%, Te≤0.004%, and Se≤0.02%.

[0029] In this invention, the element content in the low-cost, heat-corrosion-resistant, high-strength single-crystal high-temperature alloy satisfies Ta / (W+2Mo)=1~1.1, and the electron-hole number parameter Nv of the low-cost, heat-corrosion-resistant, high-strength single-crystal high-temperature alloy is ≤2.4, which can be specifically 1.95, 1.98, 1.99 or 2.

[0030] This invention also provides a method for preparing the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy described in the above technical solution, comprising the following steps: The raw materials are mixed according to the element ratio and then melted and cast sequentially to obtain the master alloy ingot. The master alloy ingot was directionally solidified to obtain a single crystal sample. The single crystal sample was heat-treated to obtain the low-cost, high-strength, heat-corrosion-resistant single crystal high-temperature alloy.

[0031] In this invention, unless otherwise specified, all materials are commercially available products.

[0032] This invention involves mixing raw materials according to elemental proportions, followed by sequential melting and casting to obtain a master alloy ingot. In this invention, the raw materials may include Ni, Cr, Co, Mo, W, Ta, Ti, Al, C, and Al-8Ce master alloys.

[0033] In this invention, the melting process may include vacuum induction melting, wherein the temperature of the vacuum induction melting can be 1520~1540℃, specifically 1530℃; the time of the vacuum induction melting can be 25~35min, specifically 30min; and the vacuum degree of the vacuum induction melting can be below 3Pa, specifically 1Pa or 2Pa.

[0034] The present invention has no special requirements for the casting process; conventional methods in the field can be used.

[0035] After obtaining the master alloy ingot, the present invention performs directional solidification on the master alloy ingot to obtain a single crystal sample. The present invention uses a high-speed solidification method for directional solidification; the remelting temperature during the directional solidification process can be 1540~1560℃, specifically 1550℃; the pulling rate can be 3.5~4.5mm / min, specifically 4mm / min.

[0036] After obtaining the single-crystal sample, the present invention performs heat treatment on the single-crystal sample to obtain the low-cost, high-strength, heat-corrosion-resistant single-crystal high-temperature alloy. In the present invention, the heat treatment may include solution treatment and aging treatment performed sequentially. In this invention, the solution treatment may include a first solution treatment and a second solution treatment performed sequentially; the holding temperature of the first solution treatment may be 1280~1300℃, specifically 1290℃; the holding time of the first solution treatment may be 1.5~2.5h, specifically 2h; the heating rate of the first solution treatment to the required holding temperature may be 5~8℃ / min, specifically 7℃ / min; the holding temperature of the second solution treatment may be 1310~1320℃, specifically 1315℃; the holding time of the second solution treatment may be 5~7h, specifically 6h; this invention can raise the temperature from the holding temperature of the first solution treatment to the holding temperature of the second solution treatment, and the heating rate of the second solution treatment to the required holding temperature may be 1.5~2.5℃ / min, specifically 2℃ / min. In this invention, the second solution treatment can be followed by cooling, and the temperature after cooling can be room temperature, which can be 20~35℃ or 25~30℃. The cooling method can include air cooling.

[0037] In this invention, the aging treatment may include a first aging treatment and a second aging treatment performed sequentially; the holding temperature of the first aging treatment may be 1130~1150℃, specifically 1140℃; the heating rate to the holding temperature required for the first aging treatment may be 8~12℃ / min, specifically 9℃ / min, 10℃ / min or 11℃ / min; the holding time of the first aging treatment may be 3~5h, specifically 4h; the first aging treatment may be cooled down, and the temperature after cooling down may be room temperature, which may be 20~35℃, or even 25~30℃; the cooling down method may include air cooling. In this invention, the holding temperature of the second aging treatment can be 860~880℃, specifically 870℃; the heating rate to the holding temperature required for the second aging treatment can be 8~12℃ / min, specifically 9℃ / min, 10℃ / min or 11℃ / min; the holding time of the second aging treatment can be 18~22h, specifically 20h; the second aging treatment can be cooled down, and the temperature after cooling down can be room temperature, which can be 20~35℃, or even 25~30℃; the cooling down method can include air cooling.

[0038] This invention also provides the application of the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy described in the above-described technical solutions, or the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy prepared by the preparation method described in the above-described technical solutions, in the preparation of high-temperature turbine blades. In this invention, the high-temperature turbine blade can be a high-temperature turbine blade for ground-based gas turbines, marine gas turbines, or near-shore / marine environment aero-engines.

[0039] The low-cost, high-strength, hot-corrosion-resistant single-crystal high-temperature alloy provided by this invention has excellent dynamic and static structural stability and outstanding high-temperature mechanical properties, while also having good oxidation resistance and hot corrosion resistance. Its comprehensive performance enables it not only to meet the stringent requirements of ground and shipboard gas turbines for high-temperature components, but also to adapt to the service conditions of aero-engines in near-marine environments.

[0040] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1 According to the element ratio, Ni, Cr, Co, Mo, W, Ta, Ti, Al, C and Al-8Ce master alloys are mixed and placed in a vacuum induction melting furnace at a temperature of 1530℃ and a vacuum degree of 2Pa for 30 minutes to obtain a molten liquid; the molten liquid is then cast to obtain a master alloy ingot. The master alloy ingot was directionally solidified using the high-speed solidification method (remelting temperature 1550℃, pulling rate 4mm / min) to obtain a single crystal sample. Single-crystal samples were heat-treated to obtain a low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy, denoted as DD413X. The specific heat treatment procedure was as follows: the temperature was increased to 1290℃ at a rate of 7℃ / min and held for 2 hours (first solution treatment); then, the temperature was increased to 1315℃ at a rate of 2℃ / min and held for 6 hours (second solution treatment); the temperature was then air-cooled to room temperature (30℃); and finally, the temperature was increased to 1140℃ at a rate of 10℃ / min and held for 6 hours (first aging treatment). After 4 hours of aging treatment, the mixture was air-cooled to room temperature (30℃), then heated to 870℃ at a rate of 10℃ / min and held for 20 hours (second aging treatment), followed by air-cooling to room temperature (30℃). The resulting low-cost, high-strength, heat-resistant single-crystal superalloy has the following elemental composition: Cr: 12.6%, Co: 9.3%, Mo: 0.4%, W: 4.1%, Ta: 4.8%, Al: 3.9%, Ti: 4.0%, C: 0.06%, Ce: 0.02%, with the balance being Ni.

[0042] Examples 2-5 A low-cost, high-strength, hot-corrosion-resistant single-crystal high-temperature alloy was prepared according to the method in Example 1. The elemental contents of the alloy are shown in Table 1.

[0043] Comparative Example 1 Commercially available PWA1483 alloy was used as a comparative example.

[0044] A low-cost, high-strength, hot-corrosion-resistant single-crystal high-temperature alloy was prepared according to the method in Example 1. The elemental contents of the alloy are shown in Table 1.

[0045] Table 1. Elemental mass percentage content of alloys in Examples 1-5 and Comparative Example 1

[0046] The Nv values ​​of the low-cost, hot-corrosion-resistant, high-strength single-crystal superalloys prepared in Examples 1-5 were calculated, with 1.98 for Example 1, 1.99 for Example 2, 1.95 for Example 3, 2 for Example 4, and 1.95 for Example 5.

[0047] According to standard GB / T 2039-2012: "Metallic Materials - Uniaxial Tensile Creep Test Method", creep performance tests were conducted on the alloy of Example 2 and the PWA1483 alloy under different temperatures and stresses. The obtained experimental data (T, σ, t) were calculated, and Larson-Miller curves were generated using Origin for scientific plotting and data analysis. Figure 1 As shown. The durability performance results of Examples 1-5 and PWA1483 are listed in Table 2.

[0048] Table 2 Durability results of Examples 1-5 and PWA1483

[0049] Combine Table 2 and Figure 1 It can be seen that the single-crystal high-temperature alloy provided by the present invention has significantly better creep performance than PWA1483 alloy, and its comprehensive performance reaches the level of high-strength, heat-resistant, and corrosion-resistant single-crystal high-temperature alloy.

[0050] The creep properties of the alloy in Example 3 were tested after long-term heat exposure at 900°C for different durations. The experimental data were used to generate high-temperature mechanical property curves using Origin scientific plotting and data analysis, as shown below. Figure 2 As shown. The creep performance results of Examples 1-5 and PWA1483 are listed in Table 3.

[0051] Table 3. Creep performance results of Examples 1-5 and PWA1483

[0052] Figure 2 The results in Table 3 show that the alloy provided by the present invention can maintain its microstructure stability and creep performance without deterioration after long-term heat exposure, demonstrating excellent microstructure stability and performance retention. After 2000 hours of heat exposure, the alloy exhibits the best creep performance.

[0053] Hot corrosion performance tests were conducted on the alloy of Example 5 and the PWA1483 alloy at 900°C. The tests were performed in triplicate, and the average value was taken. The specific values ​​are listed in Table 4. The experimental data were used to generate hot corrosion performance curves using Origin scientific plotting and data analysis. Figure 3 As shown.

[0054] Table 4. Hot corrosion performance test data of alloys in Examples 1-5 and PWA1483 alloy at 900℃.

[0055] Combine Table 4 and Figure 3 It is evident that the hot corrosion performance of the alloy provided by this invention is superior to that of the PWA1483 alloy.

[0056] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A low-cost, high-strength, hot-corrosion-resistant single-crystal superalloy, characterized in that, It includes the following elemental composition by mass percentage: Cr: 11~13%, Co: 8~11%, Mo: 0~0.5%, W: 2~5%, Ta: 4~6%, Al: 3.2~4.2%, Ti: 3.6~4.6%, C: 0~0.15%, Ce: 0.02~0.04%, with the balance being Ni and unavoidable impurities.

2. The low-cost, high-strength, hot-corrosion-resistant single-crystal high-temperature alloy according to claim 1, characterized in that, It includes the following elemental composition by mass percentage: Cr: 12.1~12.8%, Co: 8.5~10.5%, Mo: 0.3~0.5%, W: 2.6~4.4%, Ta: 4.6~5.3%, Al: 3.5~4.0%, Ti: 3.9~4.1%, C: 0.05~0.09%, Ce: 0.02~0.03%, with the balance being Ni and unavoidable impurities.

3. The low-cost, heat-corrosion-resistant, high-strength single-crystal high-temperature alloy according to claim 1 or 2, characterized in that, Ta / (W+2Mo)=1~1.1, Nv≤2.

4.

4. The method for preparing the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy according to any one of claims 1 to 3, characterized in that, Includes the following steps: The raw materials are mixed according to the element ratio and then melted and cast sequentially to obtain the master alloy ingot. The master alloy ingot was directionally solidified to obtain a single crystal sample. The single crystal sample was heat-treated to obtain the low-cost, high-strength, heat-corrosion-resistant single crystal high-temperature alloy.

5. The preparation method according to claim 4, characterized in that, The remelting temperature during the directional solidification process is 1540~1560℃, and the pulling rate is 3.5~4.5mm / min.

6. The preparation method according to claim 4, characterized in that, The heat treatment includes a solution treatment and an aging treatment performed sequentially. The solution treatment includes a first solution treatment and a second solution treatment performed sequentially. The timeliness processing includes a first timeliness processing and a second timeliness processing performed sequentially.

7. The preparation method according to claim 6, characterized in that, The first solution treatment is held at a temperature of 1280~1300℃ for 1.5~2.5h, and the heating rate is 5~8℃ / min. The second solution treatment is held at a temperature of 1310~1320℃ for 5~7 hours, with a heating rate of 1.5~2.5℃ / min. The holding temperature for the first aging treatment is 1130~1150℃, the holding time is 3~5h, and the heating rate is 8~12℃ / min; The second aging treatment is held at a temperature of 860~880℃ for 18~22h, and the heating rate is 8~12℃ / min.

8. The preparation method according to claim 4, characterized in that, The melting includes vacuum induction melting, where the temperature can be 1520~1540℃, the time is 25~35min, and the vacuum degree is below 3Pa.

9. The preparation method according to claim 4 or 8, characterized in that, The raw materials for preparation include Ni, Cr, Co, Mo, W, Ta, Ti, Al, C and Al-8Ce master alloy.

10. The application of the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy according to any one of claims 1 to 3 or the low-cost, heat-corrosion-resistant, high-strength single-crystal superalloy prepared by the preparation method according to any one of claims 4 to 9 in the preparation of high-temperature turbine blades.

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