Nickel-based braze alloy, component and method

Abstract

A nickel-based brazing filler metal (BFM) consisting essentially of: from about 12 wt% to 16 wt% chromium (Cr); up to about 5 wt% Fe; up to about 2 wt% Mo; about 1 wt% to 5 wt% of tungsten (W); about 3 wt% to 6 wt% of aluminum (Al), about 3 wt% to 6 wt% of tantalum (Ta); hafnium (Hf) from about 0.05 wt% to 1.5 wt%, carbon (C) from about 0.01 wt% to 0.1 wt%; zirconium (Zr) from about 0.005 wt% to 0.05 wt%; from about 0.005 wt% to 0.05 wt% of silicon (Si); a sum of about 0.01 to 0.05 wt% of a rare earth (e.g., Sc, yttrium (Y), actinides, and lanthanides); boron (B) from about 1.7 wt% to 2.6 wt%; the balance being essentially nickel (Ni) and unavoidable impurities. As part of a production and repair process for hot gas channel components, such as, but not limited to, blades, vanes and heat shields in gas turbines, for high strength transient liquid phase bonding (TLB) brazing of gamma'strengthened nickel-based superalloys by capillary action in the range of 1180 DEG C to 1220 DEG C. In particular, it is used for closing the top cover on the blade.

Description

Technical Field

[0001] The present invention relates to nickel-based brazing alloys, components, and joining methods. Background Art

[0002] Brazing is a process for joining two or more parts. Brazing is carried out at a temperature above the melting range of the brazing filler metal (BFM) but below the solidus temperature of the base material of the parts to be joined. The parts to be joined may include a main portion made of an alloy, especially a blade alloy, which is a nickel-based γ'-strengthened superalloy, such as IN792 or CM247CC. The parts to be brazed to the main portion may be made of the same alloy as the main portion or made of another nickel-based alloy.

[0003] The high performance of Ni-based alloys is provided by a microstructure having grains consisting of about 30 mol% to 70 mol% of γ' particles in a γ matrix.

[0004] The strengthening of the γ matrix is achieved by elements such as molybdenum (Mo), tungsten (W), or rhenium (Re).

[0005] The strengthening of the γ' particles is achieved by elements such as titanium (Ti), tantalum (Ta), or niobium (Nb).

[0006] The strengthening of grain boundaries is achieved by discrete carbides. Any strip carbides or undesirable intermetallic phases will reduce strength and ductility. Moreover, such undesirable intermetallic phases are usually rich in chromium (Cr), which reduces the effective content and thus reduces corrosion resistance and oxidation resistance.

[0007] Any deviation from the standard heat treatment process related to the main portion of the component will reduce the material properties in the main portion of the component, because for example, this deviation causes the morphology of the γ' particles to deviate from the morphology considered to be optimal.

[0008] The starting step of the standard heat treatment of as-cast components made of an alloy requires a temperature ideally above the γ' solidus to dissolve the as-cast γ' structure, especially the harmful eutectic structure. This step (hereinafter referred to as the solution step) also reduces the as-cast segregation of alloying elements. Sometimes, this step is also carried out under high inert gas pressure (HIP) to reduce as-cast porosity. The main parameters of this step are the solution temperature, the holding time at the solution temperature, and the cooling rate after the holding time. Then, the standard heat treatment continues with one or more aging steps, where the specified temperature and holding time are below the γ' solidus. It is necessary to well control the parameters of the aging step and the cooling rate after the solution step to produce the desired γ' morphology of the Ni-based alloy. The heat treatment parameters and desired morphologies are different between different alloys.

[0009] During repair and refurbishment of components, standard heat treatments are typically repeated to restore the preferred γ′ morphology that has deteriorated during use, especially in hot zones.

[0010] Alloys such as CM247CC have very high oxidation resistance potential due to their ability to form a protective Al 2 O 3 layer. This potential can be realized by combining clean production processes (especially for sulfur, which should be far below 10 ppm, preferably below 1 ppm) and adding alloys that can act synergistically to trap and neutralize residual sulfur. This will improve the adherence of the scale and thus reduce scale spallation during use. A small amount of silicon (Si) can also be added to increase the selective oxidation rate of Al 2 O 3 . This will reduce the scale thickness and will also reduce scale spallation during use. Alloys such as IN792 have oxidation resistance due to the formation of a protective Cr 2 O 3 layer. Conducting clean production processes, trapping sulfur (S), and adding silicon (Si) to accelerate selective oxidation also have beneficial effects on Cr 2 O 3 formation.

[0011] Elements commonly used to trap sulfur are hafnium (Hf), zirconium (Zr), and rare earths (such as scandium (Sc), yttrium (Y), lanthanides (La), and actinides (Ac)).

[0012] C. Sarioglu et al.'s “The Control of Sulfur Content in Nickel-Base SingleCrystal Superalloys and its Effect on Cyclic Oxidation Resistance” (Proceedings, Superalloys 1996) teaches that trace incidental elements such as sulfur (S) severely reduce the adherence of the scale, but this effect can be offset by combining clean casting and the quantitative addition of a small amount of reactive elements (RE). In the absence of RE addition, sulfur (S) must be far below 1 ppm to avoid harmful effects on scale adherence.

[0013] "Effect of Cycle Frequency on High-Temperature Oxidation Behavior of Alumina-and Chromia-Forming Alloys" by B.A. Pint et al. (Oxidation of Metals, 58(1 / 2), 73-101(2002)) teaches that trace incidental elements such as sulfur (S) severely reduce the adhesion of the oxide scale, but this effect can be counteracted by combining clean casting and the quantitative addition of a small amount of sulfur-trapping elements.

[0014] "Improvement of the Cyclic Oxidation Behaviour of Uncoated Nickel Based Single Crystal Superalloys" by P. Caron et al. (Proceedings, Materials for Advanced Power Engineering 1994) teaches the beneficial effects when combining a small amount of hafnium (Hf) and silicon (Si).

[0015] "The use of Two Reactive Elements to Optimize Oxidation Performance of Alumina-Forming Alloys" by B.A. Pint et al. (Materials at High Temperature 20(3) 375-386, 2003) and "Advances in Single Crystal Superalloys-Control of Critical Elements" by J.B. Wahl and K. Harris (Proceedings, 7 th Parsons conference, 2007) teach that the best results can be obtained when using a combination of silicon (Si) and multiple trapping elements, an example being the excellent cyclic oxidation resistance seen in the testing of Haynes 214, which contains small amounts of zirconium (Zr), silicon (Si), and yttrium (Y).

[0016] When an alloy is joined to a part made of another alloy via brazing, the joint can become a weak link in the component, and thus the designer has to ensure that the mechanical and environmental loads are relatively small compared to the loads that the alloy can withstand. This means that the usability of the component is limited. The relative weakness of the joint is caused by the limitations of the brazing process itself and the harmful interdiffusion between the alloys.

[0017] In particular, if the alloy is brazed to the same alloy, the limitations of the brazing process are the cause of the weak joint.

[0018] When the alloy is brazed to the same alloy, it is difficult to distinguish the optimal joint in the component; in alloys that are properly designed, manufactured, and heat-treated, the levels of defects (such as brittle phases, porosity, and microcracks) will be at a low level; it is actually composed of grains containing γ' particles in a γ matrix; in addition, the grain boundaries are strengthened by discrete carbides and borides; in addition, the composition of the joint is similar to that of the alloy.

[0019] The most common group of brazing alloys consists of nickel-base lean alloys that do not contain sulfur-trapping elements and use some combinations of boron (B), phosphorus (P), and silicon (Si) as melting-point inhibitor elements, see for example the selection of BNiX alloys. The advantage of these melting-point inhibitor elements is their high diffusivity. The liquidus level is below the range of 1433 K to 1523 K, which indicates that an unnecessary excess of melting-point inhibitor elements is used for brazing in the range of 1453 K to 1543 K.

[0020] Another group of brazing alloys consists of moderately strengthened nickel-base alloys to which boron (B) is added. This is illustrated by DF4B, D15, BRB, DF3, and DF6A, see the table. The addition amount of the melting-point inhibitor is usually lower than that in BNiX alloys. One reason is the higher liquidus level. Another reason is some melting-point inhibitor synergistic effects resulting from the inclusion of, for example, cobalt (Co), aluminum (Al), and tantalum (Ta).

[0021] The authors have brazed IN792 to IN792 using DF4B at 1473 K.

[0022] Although good results are obtained relative to normal standards, the joint is still a weak link in terms of creep and oxidation resistance. For a given diffusion dwell time in brazing, if the content of undesirable intermetallic compounds in the joint can be further reduced and the content of tungsten (W) and tantalum (Ta) in the joint can be increased, this is regarded as potentially beneficial. For a given process cost, it can be expected that this will increase the creep strength in the joint. If the oxidation resistance can be further enhanced, this is also considered potentially beneficial.

[0023] There are also brazing alloys based on the use of precious elements such as palladium (Pd) as melting-point inhibitors, but these brazing alloys are expensive. In addition, there are BFMs based on very high contents of hafnium (Hf) and / or titanium (Ti) and / or zirconium (Zr) and without boron (B), silicon (Si), and phosphorus (P), but if these BFMs are used, there is a high risk of precipitation of undesirable intermetallic compounds. Hafnium (Hf) also has a relatively low diffusivity. Summary of the Invention

[0024] The object of the present invention is to provide an improved nickel-based BFM, an improved joint component, and an improved brazing method.

[0025] This problem is solved by an alloy according to claim 1, a component according to claim 9, and a method according to claim 10, said alloy being used for transient liquid phase bonding at or near the solution temperature of the alloy in the main part of a component manufactured by brazing. Detailed Description

[0026] The BFM and the brazing process should preferably be selected to produce a joint as close as possible to the optimum joint at a given cost (i.e., within the practical limitations of the length of the brazing process and the cost of the alloys involved). Moreover, the brazing process should be consistent with the alloy, since the γ′ size in the main part of the component should not be significantly changed due to the introduction of the brazing process. In addition, during repair and refurbishment, the joint should not remelt, and in the worst case, it should not cause displacement of the parts brazed to the main part.

[0027] In the brazing process, the melting point inhibitor elements will diffuse from the joint into the surrounding parts. Moreover, the alloying elements from this part will diffuse into the joint. The melting point inhibitor elements should preferably have high diffusivity so that, under practically favorable brazing parameters, they will ultimately remain at a low harmless content in the surrounding parts. If the content of these melting point inhibitors in the BFM can be reduced, it will be easier to develop a favorable and cost-effective brazing process.

[0028] The key strengthening elements in the alloy have low diffusivity because that is why they are effective strengtheners. In particular, the γ matrix strengthener tungsten (W) and the γ′ particle strengthener tantalum (Ta) have low diffusivity. Many high-strength blade alloys (such as IN792 or CM247CC) therefore contain significant amounts of tungsten (W) and tantalum (Ta), as shown in the table. If tungsten (W) and tantalum (Ta) are included in the BFM, it will be easier to develop a favorable and cost-effective brazing process for such blade alloys with high-strength joints, because this will reduce the time required to achieve favorable contents of tungsten (W) and tantalum (Ta) in the joint.

[0029] If brazing is carried out at the solution temperature of the main part and the diffusion dwell time during brazing is long enough, the joint will solidify during the diffusion dwell time, i.e., TLB will be achieved. Then the joint will not remelt in any subsequent solution step (such as the solution step completed during repair and refurbishment). In the present invention, brazing is preferably carried out at or near the solution temperature to achieve TLB.

[0030] The solution temperature ranges of IN792 and CM247CC are about 1473K and 1513K respectively. To ensure that the BFM does melt at the brazing temperature, a 20K margin is left between the liquidus and the brazing temperature, which means the liquidus levels are about 1453K and 1493K respectively.

[0031] During brazing, there is a risk of sulfur (S) being introduced in the following ways: for example, impurities in the BFM, solder paste containing BFM, production of preforms containing BFM, production of foils containing BFM, handling of parts to be brazed, handling during application of BFM, handling during machining and cleaning, sulfur contained in the materials for furnace loading fixtures, and residual dirt in the furnace fixtures. This reduces the oxidation resistance of the joint and the nearby materials. Sulfur (S) also reduces the wettability during brazing. Therefore, a clean brazing process is required. It is also helpful to include getter elements that can neutralize sulfur (S) in the brazing alloy.

[0032] The alloy of the present invention contains a relatively appropriate content of boron (B) as the main melting point inhibitor element, does not use silicon (Si), phosphorus (P), or zirconium (Zr) as melting point inhibitors, intentionally adds tungsten (W) and tantalum (Ta) for strengthening the joint, uses a multi-element formulation for trapping sulfur (S), uses silicon (Si) to promote the selective oxidation of chromium (Cr) and aluminum (Al) for protective Cr 2 O 3 and Al 2 O 3 formation, and the liquidus is in the range of 1453K to 1493K. The present invention also relates to high-strength brazing of γ'-strengthened nickel-based superalloys by capillary action in the range of 1453K to 1493K. The present invention also relates to high-strength brazing as part of a production and repair process for hot gas path components (such as blades, vanes, and thermal barrier parts in gas turbines). The present invention also relates to the closure of the top cover of the blade.

[0033] The present invention belongs to the group of nickel-based BFM that is the same as DF4B, namely a moderately strengthened nickel (Ni)-based alloy with boron (B) added, see Examples SBFM1 and SBFM2 in the table. Within this group, it is characterized by: adding tungsten (W) and tantalum (Ta) to provide basic strengthening of the matrix and particles even without diffusion from the surrounding parts; not containing cobalt (Co); containing a sulfur-trapping formulation of multiple alloy elements to neutralize sulfur entering the brazing process; an appropriate content of boron (B); and containing silicon (Si) to promote the selective oxidation of chromium (Cr) and aluminum (Al), thereby producing a protective oxide layer. It is also characterized in that the desired brazing temperature is in the range of 1453K to 1543K. This combination of properties is new.

[0034] Compared with DF4B, tungsten (W) is added and tantalum (Ta) is increased. Although tungsten (W) and tantalum (Ta) will diffuse to some extent from the parts into the joint during the brazing process, these elements diffuse slowly. Therefore, when tungsten (W) and tantalum (Ta) already exist from the beginning, the content of tungsten (W) and tantalum (Ta) increases after brazing. Although tungsten (W) is added and the content of tantalum (Ta) is increased, cobalt (Co) is removed and boron (B) is reduced to reduce the content of undesirable intermetallic compounds in and around the joint. In a system with high contents of chromium (Cr) and tantalum (Ta), for example when IN792 is brazed, cobalt (Co) participates in the formation of undesirable phases. From the perspective of health and safety, metal powders are also undesirable. In addition, cobalt (Co) is a strategic alloy element, and some of the cobalt (Co) available on the world market comes from mining activities under conditions of human exploitation. Therefore, reducing the use of cobalt (Co) is beneficial.

[0035] The reduction of boron (B) is mainly achieved by the fact that the liquidus can be allowed to increase from 1408K in DF4B to a higher level associated with brazing at the solution temperature of the above alloy. The reduction of boron (B) and thus the content of harmful borides is also beneficial in terms of corrosion resistance and oxidation resistance. Borides are usually rich in chromium (Cr), which means a reduction in the effective chromium (Cr) content, and chromium (Cr) is a key element for corrosion resistance and oxidation resistance.

[0036] A sulfur-trapping formulation more advanced than the formulation in DF4B has been included. For example, this is beneficial for top cover closure, where the joint is located in a hot area and high oxidation resistance is required. The formulation is based on the synergistic effect between hafnium (Hf), zirconium (Zr) and rare earths. Silicon (Si) is also included to accelerate the selective oxidation of the protective oxide scale.

[0037] Compared with D15 (see table), tungsten (W) is added, cobalt (Co) is removed, a formulation of various alloying elements for sulfur trapping is added, and silicon (Si) for selective oxidation is added. Compared with BRB (see table), tungsten (W) and tantalum (Ta) are added, cobalt (Co) is removed, a formulation of various alloying elements for sulfur (S) trapping is added, and silicon (Si) for selective oxidation is added. Compared with DF3, aluminum (Al) and tungsten (W) are added, cobalt (Co) is removed, boron (B) is reduced, a formulation of various alloying elements for sulfur trapping is added, and silicon (Si) for selective oxidation is added. Compared with DF6A, aluminum (Al) and tungsten (W) are added, boron (B) is reduced, a formulation of various alloying elements for sulfur trapping is added, and silicon (Si) for selective oxidation is added.

[0038] The content of chromium (Cr) is between about 12.0 wt% and 16.0 wt%. Within this range, it is high enough to provide some melting point inhibitor synergistic effects, high enough to reduce the risk that the joint becomes a weak link in terms of oxidation and corrosion resistance, and low enough to avoid the excessive formation of undesirable phases.

[0039] The content of tungsten (W) is between about 1.0 wt% and 5.0 wt%. Within this range, it is high enough to provide a favorable strengthening effect and low enough to avoid the excessive formation of undesirable phases.

[0040] The content of aluminum (Al) is between about 3.0 wt% and 6.0 wt%. Within this range, it is high enough to reduce the risk that the joint becomes a weak link in terms of oxidation and corrosion resistance, high enough to contribute to the formation of γ' particles, and low enough to avoid the excessive formation of undesirable phases.

[0041] The content of tantalum (Ta) is between about 3.0 wt% and 6.0 wt%. Within this range, it is high enough to provide a favorable strengthening effect, high enough to provide some melting point inhibitor synergistic effects, and low enough to avoid the excessive formation of undesirable phases.

[0042] The content of boron (B) is between 1.7 wt% and 2.5 wt%. Within this range, it is high enough to provide a sufficient melting point inhibitor effect when brazing within the range of 1453 K to 1543 K and low enough to avoid the excessive formation of undesirable phases.

[0043] Depending on the remaining components in the brazing alloy, the components in the parts to be brazed, and the selected heat treatment process, hafnium (Hf) can optionally have a significantly strong catalytic effect on the microstructure. Hafnium (Hf) is often used to inhibit the formation of brittle structures (such as Chinese-script carbides). Based on internal experience, hafnium (Hf) can sometimes promote the formation of undesirable phases rich in hafnium (Hf) and tantalum (Ta) in the joint. Even when used in low content, hafnium (Hf) can find and bind harmful elements such as sulfur, which has a beneficial effect on oxidation resistance. The content of hafnium (Hf) is between 0.05 wt% and 1.5 wt%, with a relatively high content consistent with blade alloys (such as CM247CC), see the table.

[0044] Like tungsten (W), molybdenum (Mo) is an effective γ matrix strengthening element with a low diffusivity. Molybdenum (Mo) is known to be an active boride former, which means it can slow down the diffusion of boron (B) from the joint by incorporating it into metastable particles, so its content is up to 2.0 wt%. Regarding its compatibility with blade alloys, the content of molybdenum (Mo) is zero in IN939, a low content of 0.6 wt% in CM247CC, and 1.5 wt% to 1.8 wt% in IN792. Preferably, its content is preferably up to 2.0 wt% to enable compatibility with different alloys.

[0045] Carbon (C) is an element with a high diffusivity and can be considered, at first glance, to be easily balanced with the surrounding parts. However, internal experience shows that when using a BFM without carbon (C), sometimes joints that are substantially carbide-free are produced (which is disadvantageous). Our explanation is that as boron (B) diffuses from the joint, carbon near the joint is at least temporarily incorporated as carboboride. Carbon (C) should have a lower limit to avoid joints that are completely carbon (C)-free, but too high a carbon (C) content means a risk of forming embrittling carbide films and strip carbides. The content of carbon (C) is between 0.01 wt% and 0.1 wt%.

[0046] Silicon (Si) is an element that needs to be controlled at a relatively low content of 0.05 wt% to avoid brittle grain boundaries. Complete removal of silicon (Si) has a very adverse effect on the selective oxidation of chromium (Cr) and aluminum (Al). Preferably, the content of silicon (Si) is preferably between 0.005 wt% and 0.05 wt%.

[0047] Zirconium (Zr) is an element that provides grain boundary strengthening and acts as a sulfur (S) trap at low quantitative contents. Since it has a tendency to segregate (which can lead to incipient melting as it is a melting point depressant), it needs to be controlled at a low content. Preferably, its content is preferably between 0.005 wt% and 0.05 wt%.

[0048] Iron (Fe) can increase the activity of aluminum (Al) and thus favors oxidation resistance in and around the joint, but depending on the remaining components in the BFM and the nearby parts, iron (Fe) can also promote the formation of undesirable phases. Preferably, its content is preferably at most 5.0 wt%.

[0049] When added in low quantitative contents, rare earths (such as scandium (Sc), yttrium (Y), actinides and lanthanides) are effective sulfur (S) trappers. They act in a similar way and it has been found that using more than one rare earth is beneficial. In terms of the cost of the BFM alloy, a cost-effective method is a mixture of cerium (Ce), lanthanum (La) and yttrium (Y), which may also contain small amounts of other rare earths. The combination of La and yttrium (Y) has been found to be beneficial in tests on CMSX-4. Using either La or yttrium (Y) is convenient because many powder suppliers are familiar with these rare earths. Preferably, the content of the rare earth is preferably between about 0.01 wt% and 0.05 wt%.

[0050] Preferably, the alloy is substantially free of cobalt (Co) and / or substantially free of titanium (Ti).

[0051] The alloy of the parts to be joined of the component is different from the brazing alloy, which means that the alloy of the parts to be joined contains more or less at least one alloying element, or at least differs by at least 10%, especially at least 20%, in the content of at least one alloying element.

[0052] Test results

[0053] The creep test samples were designed to test the alloy brazed onto the blade alloy. The angled joints were subjected to a combination of tensile and shear loads. Creep tests were carried out on samples whose upper and lower parts were made of IN792 bar stock. The tests were carried out after brazing with DF4B and SBFM2, where SBFM2 is an example of the present invention, see the table.

[0054] The creep strength of the joints brazed with SBFM2 is about 3 times higher than that of the joints brazed with DF4B. The geometries, preparations and BFM applications for DF4B and SBFM2 were all carried out in the same way.

[0055] Table

[0056] alloy Ni Cr Fe Co Mo W Al Ti Ta Hf C B Zr Si P La Y IN792 B 12.5 8.5 1.8 4 3.4 4 4 0.5 0.07 0.015 0.02 CM247CC B 8 9.5 0.6 9.5 5.6 0.7 3.2 1.4 0.07 0.015 0.01 STAL125CC1 B 12.5 5 1.5 3.5 5.5 8 0.5 0.07 0.015 0.01 0.01 DF4B B 14 10 3.5 2.5 2.8 0.02 D15 B 15 10.3 3.5 3.5 2.3 BRB B 13.5 9.5 3.7 2.5 DF3 B 20 20 3 3 0.05 DF6A B 20 3 3.2 0.03 SBFM1 B 14 2 3.5 3.5 0.05 2.5 0.01 0.01 0.02 SBFM2 B 14 2 3.5 3.5 0.05 2.1 0.01 0.01 0.02 BNi1a B 14 0.06 3.2 4.5 BNi2 B 7 3 0.06 3 4.5 BNi5 B 19 0.06 10.1 BNi6 B 0.06 11 BNi9 B 15 0.06 3.6

Claims

1. A nickel-based alloy (by wt%), the nickel-based alloy comprising: 12.0% to 16.0% chromium (Cr), 1.0% to 5.0% of tungsten (W), 3.0% to 6.0% of aluminum (Al), 3.0% to 6.0% of tantalum (Ta), 0.01% to 0.1% of carbon (C), 1.7% to 2.6% of boron (B), nickel (Ni), in particular, the balance is substantially nickel (Ni) and unavoidable impurities, optionally containing rare earths in a total amount of 0.01% to 0.05% from the group consisting of scandium (Sc), yttrium (Y), lanthanides (La) and actinides (Ac), in particular containing at least two of these elements, and / or 0.05% to 1.5% of hafnium (Hf) and / or 0.005% to 0.05% of zirconium (Zr) and / or 0.005% to 0.05% of silicon (Si) and / or 0.2% to 2.0% of molybdenum (Mo) and / or 0.2% to 5.0% of iron (Fe).

2. The nickel-based alloy according to claim 1, wherein the nickel-based alloy contains (in wt%): 13.0% to 15.0% of chromium (Cr); 1.0% to 3.0% of tungsten (W), 3.0% to 4.0% of tantalum (Ta).

3. The nickel-based alloy according to claim 1, wherein the nickel-based alloy contains (in wt%): 13.5% to 14.5% of chromium (Cr), 1.5% to 2.5% of tungsten (W), 3.2% to 3.8% of tantalum (Ta), 0.03% to 0.07% of carbon (C), 1.9% to 2.2% of boron (B).

4. The nickel-based alloy according to claim 1, wherein the nickel-based alloy contains (in wt%): 13.5% to 14.5% of chromium (Cr); 1.5% to 2.5% of tungsten (W), 3.2% to 3.8% of tantalum (Ta); 0.03% to 0.07% of carbon (C); 2.3% to 2.5% of boron (B).

5. The nickel-based alloy according to any one of the preceding claims, wherein the nickel-based alloy contains a total of 0.01 wt% to 0.05 wt% of lanthanides (La) and yttrium (Y), in particular at least 0.005 wt% of lanthanides (La) and preferably at least 0.005 wt% of yttrium (Y).

6. The nickel-based alloy according to any one of the preceding claims, wherein the nickel-based alloy contains 0.01 wt% to 0.05 wt% of lanthanides.

7. The nickel-based alloy according to any one of the preceding claims, wherein the nickel-based alloy contains 0.01 wt% to 0.05 wt% of yttrium (Y).

8. The nickel-based alloy according to any one of the preceding claims, wherein the nickel-based alloy contains: 14.0 wt% of chromium (Cr); 2.0 wt% of tungsten (W); 3.5 wt% of aluminum (Al); 3.5 wt% of tantalum (Ta); 0.05 wt% of carbon (C); 2.1 wt% of boron (B); 0.01 wt% of silicon (Si); 0.01 wt% of zirconium (Zr); 0.02 wt% of yttrium (Y), optionally 0.01 wt% of hafnium (Hf).

9. The nickel-based alloy according to any one of the preceding claims, wherein the nickel-based alloy contains: 14.0 wt% chromium (Cr); 2.0 wt% tungsten (W); 3.5 wt% aluminum (Al); 3.5 wt% tantalum (Ta); 0.05 wt% carbon (C); 2.5 wt% boron (B); 0.01 wt% silicon (Si); 0.01 wt% zirconium (Zr); 0.02 wt% yttrium (Y), optionally 0.01 wt% hafnium (Hf).

10. A nickel-based alloy according to any one of the preceding claims, said nickel-based alloy being substantially free of cobalt (Co) and / or substantially free of titanium (Ti).

11. A component comprising two parts of a nickel-based alloy or a cobalt-based alloy, said component having a joint made of the alloy according to any one of claims 1 to 10.

12. A method of joining two parts of a nickel-based alloy or a cobalt-based alloy, wherein, an alloy according to any one of claims 1 to 10 is used.