Nickel-based alloys, objects made therefrom, and their uses

Abstract

The present invention relates to nickel-based alloys. More specifically, this disclosure relates to medium-to-high entropy nickel-based alloys having the following composition in weight percent (wt%): Cr 20.0-26.0; Fe <8.5; Mn <4.0; Si 0.5-2.0; Al 1.0-4.0; Ti 0.50-4.0; C <0.05; N <0.05; Ta <2.0; Nb <4.0; Co 3.0-6.0; Cu 2.1-6.0; Mo <2.0; W <1.0; optionally, B <0.005; optionally, P <0.005; optionally, S <0.005; optionally, Ca, Mg and Ce, totaling less than 0.5; Ni the remainder and incidental impurities. Nickel-based alloys meet the following requirements: a) Cu-(0.1*Fe+2.1)≧0.0 [wherein the formula, the values ​​of the alloying elements are expressed in weight percent], and b) ΔSm i x / (-R)≧1.36, TIFF2026516869000008.tif6170[where c i [where R is the mole fraction and R is the gas constant]. The nickel-based alloys according to this disclosure are primarily intended for solution-annealed objects adapted to be exposed to atmospheres in which metal dusting readily occurs.

Description

Technical Field

[0001] The present invention relates to nickel-based alloys. More particularly, the present disclosure relates to medium to high entropy nickel-based alloys suitable for use in metal dusting environments and objects made therefrom.

Background Art

[0002] Metal dusting corrosion is a complex form of high-temperature corrosion caused by carbon supersaturated gases, which causes rapid deterioration of metals and metal alloys. Usually, metal dusting corrosion is associated with temperatures of 500 to 800 °C in reaction gases containing hydrocarbons such as H2, O, CO2, H2O and / or methane. Corrosion attacks occur randomly on the surface of objects of metals or metal alloys and occur locally in the form of pits or holes. In the immediate vicinity of the pits and holes, there are corrosion products in the form of dark gray to black powder, like dust.

[0003] Increasing the carbon concentration in the reaction gas or on the surface of the metal or metal alloy increases the risk of metal dusting. The catalytic decomposition of carbon compounds into elemental carbon has been shown to play a central role in this process. Furthermore, the gas pressure and flow rate, and the exposure time also affect the risk of metal dusting corrosion.

[0004] One material that can be used for metal dusting applications is disclosed, for example, in European Patent No. 1403392 B1, which is an alloy comprising, by mass%, C: ≤0.2%, Si: 0.01–4%, Mn: 0.05–2%, P: ≤0.04%, S: ≤0.015%, Cr: ≤10–35%, Ni: 30–78%, Al: ≥0.005% but ≤4.5%, N: 0.005–0.2%, and Cu: ≤0.015–3% and Co: ≤0.015–3%, one or both, with the remainder being substantially greater than 0% but ≤10% Fe. Another example of a material suitable for metal dusting is disclosed in European Patent No. 1717330 B1, which is a metal tube having a copper-rich surface layer comprising, in mass%, the following alloy composition: C: 0.01-0.6%, Si: 0.01-5%, Mn: 0.01-10%, P: up to 0.08%, S: up to 0.05%, Cr: 15-35%, Ni: 30-75%, Cu: 0.01-10%, N: 0.001-0.25%, Al: 0.001-10%, O: up to 0.02%, with the remainder being iron and impurities.

[0005] Furthermore, recent material developments have made alloys such as VDM® Alloy 699 XA suitable for metal dusting applications available. Fe-Ni-Cr steel and austenitic alumina-forming steel can also be used for these applications. However, although these alloys are currently used in metal dusting environments, they are still affected by metal dusting corrosion. Therefore, there is a need for improved metal alloys that are highly resistant to the corrosion that occurs in these environments and can be used for long periods in metal dusting environments. In addition, the aforementioned alloys are difficult to hot work and can be difficult to weld. [Overview of the project]

[0006] Therefore, one aspect of the present disclosure is to provide a nickel-based alloy having excellent metal dusting resistance. In other words, objects containing this nickel-based alloy are ideal for use in environments where metal dusting corrosion readily occurs.

[0007] Therefore, this disclosure provides nickel-based alloys having the following composition in weight percent (wt%). Cr 20.0~26.0; Fe less than 8.5; Mn less than 4.0; Si 0.5~2.0; Al 1.0~4.0; Ti 0.50~4.0; C less than 0.05; N less than 0.05; Ta less than 2.0; Nb less than 4.0; Co 3.0~6.0; Cu 2.1~6.0; Mo less than 2.0; W less than 1.0; Optionally, B less than 0.005; Optionally, P < 0.005; Optionally, S less than 0.005; Selectively, Ca, Mg, and Ce must be less than 0.5 in total; Ni residue and associated impurities; Having the composition, Nickel-based alloys further meet the following requirements: a) Cu-(0.1*Fe+2.1)≧0.0 [wherein the formula, the values ​​of the alloying elements are expressed in weight percent], and b)ΔSm i x / -R≧1.36 [where c i [where R is the mole fraction, and R is the gas constant].

[0008] The inventors have surprisingly found that the alloy of the present invention satisfies the above requirements, namely Cu-(0.1*Fe+2.1)≧0.0 and ΔSm iWe discovered that when x / -R≧1.36 is satisfied, the resulting alloy or an object made from it exhibits excellent metal dusting resistance. Without being bound by any theory, it is believed that these two requirements affect the carbon diffusion rate, and by satisfying these requirements, carbon deposition on the surface of the nickel-based alloy is eliminated or at least reduced, thereby reducing or completely eliminating metal dusting degradation of the nickel-based alloy. Therefore, the inventors diligently conducted research to solve the above problem and succeeded in controlling the composition and carbon diffusion rate of the nickel-based alloy of the present invention. As a result, a nickel-based alloy with metal dusting resistance that can be subjected to both hot working and welding was obtained.

[0009] Furthermore, this disclosure relates to an object comprising a nickel-based alloy as defined above or below.

[0010] The present invention also relates to the use of an object containing a nickel-based alloy as defined above or below in a metal dusting environment, such as an environment containing or consisting of a carbon supersaturated gas. [Brief explanation of the drawing]

[0011] [Figure 1] The results of a metal dusting test on the sample of the present invention and a comparative sample are shown. [Figure 2a] Images of comparative samples after the metal dusting test are shown. [Figure 2b] Images of comparative samples after the metal dusting test are shown. [Figure 2c] The image shows the sample of the present invention after the metal dusting test. [Modes for carrying out the invention]

[0012] The present invention relates to a nickel-based alloy having the following composition (weight percent, wt%). Cr 20.0~26.0; Fe less than 8.5; Mn less than 4.0; Si 0.5 to 2.0; Al 1.0 to 4.0; Ti 0.50 to 4.0; C less than 0.05; N less than 0.05; Ta less than 2.0; Nb less than 4.0; Co 3.0 to 6.0; Cu 2.1 to 6.0; Mo less than 2.0; W less than 1.0; Ni the balance and incidental impurities; having the composition of, optionally, B less than 0.005; optionally, P less than 0.005; optionally, S 0.005; less than; optionally, Ca, Mg and Ce, in total less than 0.5; Ni the balance and incidental impurities; having the composition of, The nickel-based alloy has the following requirements, a) Cu - (0.1*Fe + 2.1) ≥ 0.0 [where the numerical values of the alloying elements are expressed in wt%], and b) ΔSm i x / -R ≥ 1.36, TIFF2026516869000002.tif6170 [where c i is the mole fraction and R is the gas constant].

[0013] The nickel-based alloy of the present invention has been found to form a passive layer containing oxides on the surface during operation in a metal dusting environment. This surface layer prevents contact between the carburizing or reducing atmosphere and the nickel-based alloy, and the formation time of metal dusting pits or general corrosion is longer compared to conventional materials.

[0014] The present invention also provides a powder of the nickel-based alloy defined above or below. Therefore, the nickel-based alloy defined above or below may be in the form of a powder. The powder can be obtained by atomization.

[0015] The present invention also relates to an object comprising a nickel-based alloy as defined above or below. The object may be, but is not limited to, a tube, composite tube, pipe, rod, hollow body, billet, bloom, strip, wire, plate, or sheet. In this disclosure, the term “composite tube” means a multilayer tube comprising at least two different alloys, at least one of which is a nickel-based alloy as defined above or below, and this alloy is the inner layer, i.e., the layer exposed to the metal dusting environment.

[0016] Therefore, the nickel-based alloys according to this disclosure are primarily intended to impart to objects manufactured therefrom the ability to be exposed to atmospheres in which metal dusting readily occurs, such as gaseous carburizing atmospheres or reducing atmospheres. Gaseous carburizing atmospheres may include reactive gases such as H2, CO, CO2, H2O, and / or hydrocarbons such as methane. Typically, metal dusting corrosion occurs at temperatures of 500-800°C.

[0017] For example, welding may be required when using objects containing the nickel-based alloy of the present invention, such as tubes in ammonia plants. When the nickel-based alloy of the present invention or an object made therefrom is in a solution-annealed state, a precipitate-free austenite matrix is ​​ensured, thus achieving good weldability. Therefore, when the nickel-based alloy of the present invention or an object made therefrom is in a solution-annealed state, it will have good weldability, high strength, and excellent resistance to metal dusting.

[0018] Accordingly, this disclosure also relates to solution-annealed objects containing nickel-based alloys as defined above or below. Solution-annealed objects can be selected from tubes, composite tubes, pipes, rods, hollow bodies, billets, blooms, strips, wires, plates, or sheets. Solution-annealed objects containing nickel-based alloys as defined above or below may have a fully austenitic crystalline structure. According to embodiments, solution-annealed objects as defined above or below may have a tensile strength exceeding 800 MPa when measured at 650°C according to SS-EN ISO 6892-1.

[0019] According to the embodiment, a solution-annealed object comprising a nickel-based alloy as defined above or below can be manufactured using a conventional metallurgical manufacturing method comprising the steps of casting, hot working and / or cold working of a molten material, followed by a solution annealing step, the solution annealing step being carried out at a temperature of 1100-1200°C for 1-8 hours, for example, 1-5 hours.

[0020] According to the embodiment, a solution-annealed object containing a nickel-based alloy as defined above or below may also be manufactured using a powder metallurgy manufacturing method, such as hot isostatic pressing (HIP) or additive manufacturing (AM), followed by a solution annealing step at a temperature of 1100-1200°C for 1-8 hours, for example, 1-5 hours.

[0021] This disclosure also relates to using solution-annealed objects as defined above or below in an environment containing or consisting of a carbon supersaturated gas in a temperature range of 500°C to 800°C. For example, in a gaseous carburizing or reducing atmosphere containing H2, CO, CO2, H2O, or hydrocarbons.

[0022] Next, we will discuss alloying elements in more detail. The terms "weight %" and "wt%" are used interchangeably. The upper and lower limits of individual components of a composition can be freely combined within the broadest range described in the claims, unless otherwise explicitly disclosed. It should also be considered that the list of properties and contributions described for specific elements is not exhaustive.

[0023] Chromium (Cr) 20.0-26.0% by weight Cr is an alloying element added to influence corrosion resistance by forming a stable passive layer on the surface, ensuring sufficient corrosion resistance even at high temperatures. The formed passive layer provides resistance to metal dusting. To reliably obtain this effect, the Cr content must be 20.0% by weight or more. According to the embodiment, to further reliably obtain this effect, the Cr content may be at least 20.5% by weight. However, if the Cr content exceeds 26.0%, the toughness of the alloy decreases, and the hot workability deteriorates, making processing difficult. Also, if the Cr content exceeds 26.0%, there is a risk of intermetallic phase formation and embrittlement. According to the embodiment, the Cr content does not need to exceed 25.5% by weight.

[0024] Iron (Fe) less than 8.5% by weight Fe can be optionally added to nickel-based alloys. However, it has been found that too much Fe in the alloy of the present invention adversely affects the metal dusting resistance. Since excessively reducing the Fe content significantly increases manufacturing costs, it is not necessary to reduce the Fe content to 0% by weight, and therefore the Fe content is 8.5% by weight or less, for example, 6.5% by weight or less. According to the embodiment, the Fe content may be in the range of 0.5 to 8.5% by weight.

[0025] Manganese (Mn) less than 4.0% by weight Since Mn is a stabilizer of the austenite structure, it can be added as needed and can be used to replace part of the content of the expensive alloying element Ni. Furthermore, Mn helps in deoxidation during dissolution and improves the workability of nickel-based alloys. However, if the Mn content is too high, the formation of a passivation layer containing Cr will decrease. Therefore, the Mn content is 4.0% by weight. According to the embodiment, the Mn content is 3.0% by weight or less. According to the embodiment, the Mn content may be in the range of 0.1 to 4.0% by weight, for example, 0.1 to 3.0% by weight or less.

[0026] Silicon (Si) 0.5-2.0% by weight Si is added to improve metal dusting resistance. In high-temperature environments, Si forms a stable passive layer on the surface, affecting corrosion resistance and ensuring good metal dusting resistance. To obtain this effect, the Si content must be at least 0.5% by weight. According to embodiments, the Si content may be at least 0.6% by weight. However, if the Si content exceeds 2.0% by weight, it may adversely affect weldability and microstructure stability. According to embodiments, the Si content does not need to exceed 1.8% by weight, such as 1.6% by weight.

[0027] Aluminum (Al) 1.0-4.0% by weight Al is an element added to improve both metal dusting resistance and creep strength. In high-temperature environments, Al forms a stable passive layer on the surface, affecting corrosion resistance and ensuring good metal dusting resistance. To obtain this effect, the Al content must be at least 1.0% by weight. According to embodiments, the Al content may be at least 2.0% by weight. On the other hand, if the Al content exceeds 4.0% by weight, it may adversely affect weldability and hot workability. According to embodiments, the Al content does not need to exceed 3.5% by weight.

[0028] Titanium (Ti) 0.5-4.0% by weight Ti is an element added to improve metal dusting resistance, high-temperature strength, and creep strength. In high-temperature environments, Ti forms a stable passive layer on the surface, enhancing corrosion resistance and providing good metal dusting resistance. To achieve this effect, the Ti content must be at least 0.5% by weight. According to the embodiment, the Ti content may be at least 0.7% by weight. On the other hand, if the Ti content exceeds 4.0% by weight, it may adversely affect weldability and hot workability. According to the embodiment, the Ti content does not need to exceed 3.0% by weight.

[0029] Carbon (C) less than 0.05% by weight The carbon content should be as low as possible and should not be added intentionally. Carbon is a stabilizer of the austenite structure, and the addition of small amounts of carbon may increase the high-temperature strength. Too much carbon reduces toughness, so the amount of carbon should be less than 0.05% by weight. According to the embodiment, the carbon content may be in the range of 0.001 to 0.05% by weight.

[0030] Nitrogen (N) less than 0.05% by weight The N content should be as low as possible and should not be intentionally added to nickel-based alloys. N is a stabilizer of the austenite structure, and the addition of small amounts of N may increase the high-temperature strength. Too much N can lead to the formation of unwanted aluminum nitrides, so the N content should be less than 0.05% by weight. According to embodiments, the N content may be in the range of 0.01 to 0.05, for example, 0.02 to 0.05% by weight.

[0031] Niobium (Nb) 0.01-4.0% by weight Nb is an element added to improve metal dusting resistance, high-temperature strength, and creep strength. To obtain this effect, the Nb content must be at least 0.01% by weight. According to embodiments, to further improve these effects, the Nb content may be at least 0.5% by weight, for example, at least 1.0% by weight, for example, at least 2.0% by weight. However, if the Nb content exceeds 4.0% by weight, hot workability is adversely affected, and there is a risk of unwanted Laves phase formation. According to embodiments, the Nb content does not need to exceed 3.5% by weight.

[0032] Tantalum (Ta) less than 2.0% by weight Ta may be added to improve metal dusting resistance, entropy value, high-temperature strength, and creep strength. According to embodiments, the Ta content may be at least 0.03% by weight, for example, at least 0.5% by weight, for example, at least 0.75% by weight, for example, at least 0.85% by weight. However, if the Ta content exceeds 2.0% by weight, hot workability may be adversely affected, and there is a risk of undesirable Laves phase formation. According to embodiments, the Ta content does not need to exceed 1.5% by weight. According to embodiments, the Ta content may be in the range of 0.03 to 2.0% by weight, for example, 0.5 to 2.0% by weight.

[0033] Cobalt (Co) 3.0-6.0% by weight Co is an effective austenite structure stabilizer and is added to increase entropy, high-temperature strength, and creep strength. To ensure this effect is achieved, the Co content must be 3.0% by weight or more. According to the embodiment, the Co content is at least 3.2% by weight, for example, at least 3.4% by weight. On the other hand, if the Co content exceeds 6.0% by weight, it may adversely affect hot workability.

[0034] Copper (Cu) 2.1~6.0% by weight Cu is an effective austenite structure stabilizer and is added to improve metal dusting resistance. To ensure this effect, the Cu content must be at least 2.1% by weight, for example, at least 2.5% by weight. On the other hand, if the Cu content exceeds 6.0% by weight, it may adversely affect weldability and hot workability. According to the embodiment, the maximum Cu content may be 5.0% by weight.

[0035] Molybdenum (Mo) less than 2.0% by weight Since Mo increases the entropy value, it can be optionally added to nickel-based alloys. Therefore, when added, the Mo content is 2.0% by weight or less, for example, 1.0% by weight or less. According to the embodiment, the Mo content may be in the range of 0.01 to 0.05% by weight.

[0036] Tungsten (W) less than 1.0% by weight Since W increases the entropy value, it can be optionally added to nickel-based alloys. Therefore, when added, the W content is 1.0% by weight or less, for example, 0.5% by weight or less. According to the embodiment, the Mo content may be in the range of 0.01 to 1.0% by weight.

[0037] Boron (B) less than 0.005% by weight B is an element added to improve hot workability and creep strength. However, if the B content exceeds 0.005% by weight, it may adversely affect weldability. According to the embodiment, the B content may be in the range of 0.0001 to 0.005% by weight.

[0038] Phosphorus (P) less than 0.005% by weight While phosphorus (P) is effective in suppressing the reaction between carburizing gas and nickel-based alloys, it has a very adverse effect on hot workability and weldability. For these reasons at least, the P content is less than 0.005% by weight. According to the embodiment, the P content may be in the range of 0.0001 to 0.005% by weight.

[0039] Sulfur (S) less than 0.005% by weight S is effective in suppressing the reaction between carburizing gas and nickel-based alloys, but it has a very adverse effect on hot workability and weldability. For these reasons at least, the S content is less than 0.005% by weight. According to the embodiment, the S content may be in the range of 0.0001 to 0.005% by weight.

[0040] Calcium (Ca), Magnesium (Mg), Cerium (Ce) less than 0.5% by weight Ca, Mg, and Ce are elements added to improve hot workability. When added, the total amount is less than 0.5% by weight. According to the embodiment, the total content of Ca, Mg, and Ce may be in the range of 0.01 to 0.5% by weight.

[0041] In the nickel-based alloy of the present invention, the remainder consists of nickel (Ni) and incidental impurities.

[0042] According to one embodiment, the Ni content may be at least 39% by weight, for example, at least 44% by weight, or for example, at least 49% by weight. According to one embodiment, the Ni content may be less than 76% by weight, for example, less than 71% by weight, for example, less than 66% by weight, or for example, less than 61% by weight. In one embodiment, the Ni content may be in the range of 50 to 60% by weight.

[0043] According to the embodiment, the austenitic nickel-based alloy contains all the alloying elements described above or below within the ranges described above or below, or consists of all the alloying elements described above or below. According to the embodiment, the austenitic nickel-based object contains all the alloying elements described above or below within the ranges described above or below, or consists of all the alloying elements described above or below.

[0044] "Incidental impurities" as used herein refer to substances that contaminate nickel-based alloys during the industrial production of nickel-based alloys due to raw materials such as ore and scrap, as well as various factors in the manufacturing process. These substances are permitted to contaminate nickel-based alloys within the ranges described below without adversely affecting the properties of the nickel-based alloy as defined above or below. Examples of incidental impurities include oxygen (O), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), tin (Sn), lead (Pb), bismuth (Bi), and yttrium (Y). In some embodiments, the total content of incidental impurities may be a maximum of 0.05% by weight, for example, a maximum of 0.025% by weight, or for example, a maximum of 0.010% by weight.

[0045] Furthermore, as described above or below, nickel-based alloys must also satisfy the following two requirements in addition to the range of alloying elements. The first requirement, Cu-(0.1*Fe+2.1)≧0.0 (value is in weight %), represents the relationship between Cu and Fe, and these elements have been found to have a significant impact on metal dusting resistance. Surprisingly, the inventors discovered that alloys satisfying this formula have excellent metal dusting resistance. According to the embodiment, when Cu-(0.1*Fe+2.1)≧1.0, nickel-based alloys may have even better metal dusting resistance. According to the embodiment, when Cu-(0.1*Fe+2.1) is 2.0 or greater, metal dusting resistance may be further improved.

[0046] The second requirement, ΔSm i x / -R≧1.36, TIFF2026516869000003.tif6170(in the formula, c iThe formula (where ΔSm is the mole fraction and R is the gas constant) is related to the entropy of the alloy. While the entropy of the alloy affects the metal dusting resistance, the inventors surprisingly discovered that by satisfying this formula, the alloy exhibits excellent metal dusting resistance. Thus, the metal dusting degradation of nickel-based alloys is significantly reduced compared to known materials. According to the embodiment, in order to further improve the metal dusting resistance, ΔSm i x / -R is ≥ 1.48. Therefore, by satisfying both of these requirements, the nickel-based alloys defined above or below will have excellent metal dusting resistance.

[0047] The present invention will be described in further detail below with reference to exemplary embodiments. However, the present invention is not limited to the exemplary embodiments described herein and can be modified within the scope of disclosure. [Examples]

[0048] Eleven nickel group samples with the chemical composition specified in Table 1 were prepared and tested accordingly. TIFF2026516869000004.tif99170

[0049] The molten material was manufactured on a laboratory scale by vacuum induction melting (VIM), cast, and machined into a 24 mm diameter rod. The rod was then hot-rolled to approximately 7 x 7 mm at a temperature of approximately 1180°C, and subsequently solution-annealed at a temperature of approximately 1150°C for 4 hours.

[0050] Solution-annealed samples were subjected to various tests described below. Tensile strength (Rm) and elongation (A) were measured at room temperature by tensile testing in accordance with SS-EN ISO 6892-1. The samples were oriented longitudinally with respect to the rolling direction.

[0051] The results are shown in Table 2. From the results, the highest tensile strengths under solution-annealed conditions, measured at room temperature, were achieved in samples 3, 4, and 5, with tensile strengths exceeding 800 MPa. TIFF2026516869000005.tif98170

[0052] Furthermore, tensile strength (Rm) and elongation (A) were measured by tensile testing at 650°C in accordance with SS-EN ISO 6892-1. The results are shown in Table 3. From the results, the highest tensile strength under solution annealing conditions measured at 650°C was obtained for heated materials number 3 and 4, both of which had a tensile strength of 800 MPa or higher. TIFF2026516869000006.tif92170

[0053] Metal dusting test The solution-annealed samples were polished on the front and back with 320, 800, and finally 1200 grit, and on the sides with 800 and 1200 grit. To remove all residue, the samples were washed with acetone and isopropanol.

[0054] The metal dusting test was conducted in a tubular furnace at 620°C, 18 bar, in a carburizing gas environment of 47% CO, 47% H2, 2% H2O, and 4% CO2, using a quasi-isothermal exposure test with static argon and cooling with fluid argon (both at 1 bar).

[0055] After a thorough cleaning process, gravimetric measurements were performed on the exposed samples, and the results are shown in Figure 1. This figure shows the mass change of the tested samples, where a positive slope indicates an increase in mass, such as the formation of protective oxides. A negative slope in the curve indicates a loss of mass, such as the formation of metal dust pits.

[0056] The sample of the present invention is shown by a dashed line and shows a positive slope even after 1960 hours of exposure. The comparative sample is shown by a solid line and both begin to show negative mass change values ​​before 1500 hours of exposure.

[0057] Furthermore, the appearance of the samples after exposure can be divided into three typical groups. Figure 2a shows Group 1, which includes a comparative example with metal dust pits on all planes, edges, and corners.

[0058] Figure 2b shows Group 2, which includes a comparative example where the edge is subjected to a metal dusting attack.

[0059] Figure 2c shows Group 3, which includes samples of the present invention that show no signs of metal dusting adhesion on the plane or edges.

[0060] Therefore, as shown in the figure, the nickel-based sample alloys included within the scope of the present invention exhibit significantly superior resistance to metal dusting compared to comparative samples, and no signs of metal dusting are observed on the surface or edges of the samples of the present invention.

Claims

1. Nickel-based alloys, expressed in the following weight percentages (wt.%): Cr 20.0-26.0; Fe less than 8.5; Mn less than 4.0; Si 0.5-2.0; Al 1.0-4.0; Ti 0.50-4.0; C less than 0.05; N less than 0.05; Ta less than 2.0; Nb less than 4.0; Co 3.0-6.0; Cu 2.1-6.0; Mo less than 2.0; W less than 1.0; Optionally, B less than 0.005; Optionally, P is less than 0.005; Optionally, S less than 0.005; Optionally, the total amount of Ca, Mg, and Ce should be less than 0.5; Ni residue and associated impurities; Having the composition, The nickel-based alloy meets the following requirements: a) Cu - (0.1 * Fe + 2.1) ≥ 0.0 [wherein the formula, the values ​​of the alloying elements are given in weight percent], and b)ΔSm ｉ x / (-R)≧1.36、 [In the formula, c ｉ [where R is the mole fraction and R is the gas constant] A nickel-based alloy that satisfies the following conditions.

2. The nickel-based alloy according to claim 1, wherein the Fe content is less than 6.5% by weight.

3. The nickel-based alloy according to claim 1 or 2, wherein the Al content is 2.0 to 4.0% by weight.

4. A nickel-based alloy according to any one of claims 1 to 3, wherein the Ti content is 0.5 to 2.0% by weight.

5. A nickel-based alloy according to any one of claims 1 to 4, wherein the Nb content is 2.0 to 3.5% by weight.

6. A nickel-based alloy according to any one of claims 1 to 5, wherein the Co content is 3.0 to 5.0% by weight.

7. A nickel-based alloy according to any one of claims 1 to 6, wherein the Cu content is 3.0 to 5.0% by weight.

8. A nickel-based alloy according to any one of claims 1 to 7, wherein Cu-(0.1*Fe+2.1) is ≥ 1.0, for example, Cu-(0.1*Fe+2.1) is ≥ 2.

0.

9. ΔSm ｉ A nickel-based alloy according to any one of claims 1 to 8, wherein x / -R is ≥ 1.

48.

10. The nickel-based alloy according to any one of claims 1 to 9, wherein the nickel-based alloy is in the form of a powder.

11. An object comprising a nickel-based alloy according to any one of claims 1 to 10.

12. The object according to claim 11, wherein the object is selected from tubes, composite tubes, pipes, rods, hollow bodies, billets, blooms, strips, wires, plates, or sheets.

13. The object according to claim 11 or 12, wherein the object is solution annealed.

14. Use of the object according to claim 11 or 12 in an environment in which metal dusting corrosion occurs.

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