CN120898011A

CN120898011A - Nickel-based alloys, powders, and methods with high oxidation resistance and good wear resistance

Info

Publication number: CN120898011A
Application number: CN202480018352.1A
Authority: CN
Inventors: 马格努斯·哈斯尔奎斯特
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2023-03-17
Filing date: 2024-01-29
Publication date: 2025-11-04
Also published as: GB2628174A; KR20250157446A; WO2024193876A1; EP4680780A1

Abstract

本发明涉及基于镍的超级合金，包含(以重量％计)：6.0％至12.0％的钴(Co)；6.0％至12.0％的铁(Fe)；14.0％至18％的铬(Cr)；最高至2.0％的钼(Mo)；2.0％至5.0％的钨(W)；4.0％至5.5％的铝(Al)；2.0％至3.5％的钽(Ta)；最高至0.2％的钛(Ti)；0.03％至0.3％的碳(C)；0.005％至0.03％的硼(B)；0.005％至0.03％的锆(Zr)；0.005％至0.5％的硅(Si)；0.002％至0.2％的Y、Sc、镧系元素和锕系元素的合计含量；0.05％至3.0％的铪(Hf)；最高至2.0％的锰(Mn)；镍(Ni)以及不可避免的杂质。This invention relates to nickel-based superalloys comprising (in weight percent): 6.0% to 12.0% cobalt (Co); 6.0% to 12.0% iron (Fe); 14.0% to 18% chromium (Cr); up to 2.0% molybdenum (Mo); 2.0% to 5.0% tungsten (W); 4.0% to 5.5% aluminum (Al); 2.0% to 3.5% tantalum (Ta); and up to 0.2% titanium (Ti). 0.03% to 0.3% carbon (C); 0.005% to 0.03% boron (B); 0.005% to 0.03% zirconium (Zr); 0.005% to 0.5% silicon (Si); 0.002% to 0.2% total content of Y, Sc, lanthanides and actinides; 0.05% to 3.0% hafnium (Hf); up to 2.0% manganese (Mn); nickel (Ni) and unavoidable impurities.

Description

Nickel-based alloy, powder and method with high oxidation resistance and good wear resistance

The present invention relates to nickel-based alloys having high oxidation resistance, good hot corrosion resistance, good wear resistance, adequate formability and ductility (e.g., for heat sealing structures in gas turbines), and adequate weldability (e.g., for manual welding, laser Metal Deposition (LMD), and powder bed processes such as laser powder bed melting (laser powder bed fusion, LPBF)).

The turbine section in the gas turbine includes blades (blades) made of a nickel-based highly gamma' strengthened superalloy (referred to herein as a blade alloy), an impeller (vane), and a heat shield. It also includes sealing structures made from thin sheets of solid solution strengthened and/or up to moderately gamma' strengthened nickel-based superalloys, such as strips between components, baffle seal plates, and honeycomb structures.

Approximately, the microstructure of a properly heat treated blade alloy consists of grains consisting essentially of gamma prime particles embedded in a gamma matrix. Gamma' is approximately Ni ₃ Al in which elements such as titanium (Ti), tantalum (Ta), hafnium (Hf), and niobium (Nb) are solid-dissolved. Gamma is approximately nickel (Ni) in which elements such as cobalt (Co), iron (Fe), molybdenum (Mo), and tungsten (W) are solid-dissolved. Grain boundaries are modified with borides and carbides that provide adhesion between grains, zirconium (Zr) also provides grain boundary strength. However, although, for example, aluminum (Al) is mainly distributed to the γ' phase, some aluminum (Al) is distributed to the γ phase. The aluminum (Al) partitioning behavior is not the same for all blade alloys, which is affected by the levels of other alloying elements.

If the blade alloy comprises at least about 12.0 wt.% chromium (Cr), the blade alloy is approximately capable of forming a protective (i.e., continuous and adherent) layer of Cr ₂O₃ within its oxide scale.

Conventionally, IN land-based gas turbines, the blade alloy is selected from the group of industrial gas turbine (industrial gas turbine, IGT) alloys, such as IN738LC, with >12.0 wt% chromium (Cr), capable of forming protective Cr ₂O₃, but containing too little aluminum (Al) and too much titanium (Ti) to form protective Al ₂O₃. Since Cr ₂O₃ is protective only up to about 1123K for long-term service (typically >30 kilohours between overhauls), increased firing temperatures (firing temperature) in land-based gas turbines require the introduction of coatings on IGT alloys and/or the use of blade alloys capable of forming protective Al ₂O₃ (e.g.

STAL125CC 1) replaces IGT alloys.

Traditionally, in land-based gas turbines, plate-like alloys such as Hastelloy-X and C-263 are used for sealing the structural members. These alloys are as well able to form protective Cr ₂O₃ as IGT alloys, but not protective Al ₂O₃ and are therefore limited by the same 1123K. When the allowable metal temperatures in the impeller, blades and heat shields are raised due to the introduction of the coating and the blade alloy forming Al ₂O₃ (e.g., STAL125CC 1), it is difficult to avoid the metal temperature increase also in the sealing structure.

Since it is not generally feasible to apply a coating on such a structure, the coating is prone to cracking when the plate-like alloy is bent and distorted during production and/or when it is attached, which leads to oxidation problems of conventional plate-like alloys.

A generally useful solution to these problems is to replace the conventional plate alloy with the plate alloy Haynes214, which has 16.0 wt% chromium (Cr) and 4.5 wt% aluminum (Al), which is capable of forming protective Cr ₂O₃ up to about 1123K and protective Al ₂O₃ above about 1123K. However, as the firing temperature increases, it would be beneficial to have an even higher oxidation resistance.

"B.A. pint et al 'The use of two reactive elements to optimize oxidation performance of alumina-forming alloys',Materials at High Temperatures,2003" teaches that high cyclic oxidation resistance in Haynes214 is provided by its ability to form protective alumina and inclusion of Zr, Y and Si.

It should also be noted that Haynes214 is solderable, meaning that it can also be used in a soldering process. This includes manual welding using welding wire and Laser Metal Deposition (LMD). This also includes LMD using powder. This also includes powder bed processes using powders, such as LPBF.

Accordingly, the present invention aims to solve this problem.

It is an object of the present invention to provide an alloy that provides higher oxidation resistance, creep resistance and wear resistance than Haynes214, but which can still be used for the production and shaping of metal sheets. The metal sheet may be used, for example, for heat sealing structural members in gas turbines.

It is another object of the present invention to utilize the alloy to produce welding wire for welding and LMD. It is another object of the present invention to utilize the alloy to produce powders for LMD as well as powder bed processes such as, but not limited to LPBF.

It is another object of the present invention to utilize the alloy for casting of components (e.g., seals) that can function as components of cooling systems as well as provide damping. In the latter case, high wear resistance is beneficial.

This problem is solved by an alloy according to claim 1, a powder according to claim 11 and a method according to claim 12.

The alloy of the present invention is provided by the following composition (in wt.%):

6.0 to 12.0% cobalt (Co)

6.0 To 12.0% of iron (Fe)

14.0 To 18% chromium (Cr)

2.0 To 5.0% of tungsten (W)

4.0 To 5.5% of aluminum (Al)

2.0 To 3.5% tantalum (Ta)

0.03 To 0.3% of carbon (C)

0.005 To 0.03% of boron (B)

0.005% To 0.03% zirconium (Zr)

0.005% To 0.5% silicon (Si)

0.002 To 0.04% of yttrium (Y), scandium (Sc), hafnium (Hf) with a total content of 0.05 to 3.0% of lanthanoid elements and actinoid elements

Up to 2.0% molybdenum (Mo)

Up to 0.2% titanium (Ti)

Up to 2.0 wt.% manganese (Mn)

The presence of unavoidable impurities is not limited to,

Nickel (Ni), especially the remainder being nickel (Ni).

It would be further beneficial to have improved creep strength and wear resistance relative to Haynes 214. It should be noted that when Haynes214 contains 16.0 wt.% chromium (Cr) and 4.5 wt.% aluminum (Al) to enable the formation of protective Al ₂O₃, it is also produced with a clean production process and contains low measured levels of Zr and Y for sulfur absorption. This is done to suppress the very adverse effect of sulfur (S) on the adhesion of the Al ₂O₃ layer.

Table nominal compositions (in wt.%) for some commercial alloys and embodiments of the invention. RE represents rare earth. AlA is the relative aluminum activity at 1273K. M is a mixture of 0.1 wt% La and 0.1 wt% Y, or 0.2 wt% misch metal alloy.

Haynes214 is reinforced with gamma prime particles up to a gamma prime solvus of about 1193K, but neither the gamma matrix nor the gamma prime particles are reinforced. The gamma prime particles provide creep, yield and wear resistance. Haynes214 has a low carbon content and therefore less creep, yield and wear resistance provided by carbides.

It would be advantageous if the gamma and gamma' phases were at least moderately strengthened to provide higher strength and wear resistance.

Furthermore, it would be advantageous if more and/or harder carbides were formed to further increase the strength and in particular the wear resistance.

It would be further advantageous if gamma' were stable up to at least 1273K to provide strength and wear resistance in the range 1173K to 1273K, as sealing structures (e.g., sealing strips) may withstand such temperatures in high firing temperature gas turbines.

At the same time, however, it should preferably not increase the gamma' level at lower temperatures, as this will lead to an increase in the concentration of alloying elements in the gamma matrix that tend to form brittle phases.

In one embodiment, E214LC is added with tungsten and tantalum relative to Hayne, 214, thereby increasing the strength of the gamma and gamma' phases, respectively. This increases the predicted gamma prime solvus by about 100K, and the predicted gamma prime curve is very close to the preferred gamma prime curve. Despite the addition of cobalt (Co), tungsten (W) and more iron (Fe) and due to the fact that the gamma' content is moderate, the level of prediction of the undesired phase is low. A beneficial change in the slope of the gamma 'curve is the effect of the cobalt (Co) and iron (Fe) ratios that affect the partitioning of aluminum (Al) between the gamma phase and the gamma' phase.

The predicted aluminum activity at 1273K is very significantly improved over Haynes214 and is also significantly higher than, for example, the high oxidation resistance blade alloy STAL CC1. Since aluminum activity is an indicator of oxidation resistance, this strongly suggests an improvement in oxidation resistance over Haynes 214. The cobalt (Co) +iron (Fe) ratio contributes significantly to the enhanced aluminum (Al) activity, but the inclusion of tantalum (Ta) and chromium (Cr) are also beneficial. The potential for increased oxidation resistance via increased aluminum (Al) activity may not be realized unless the detrimental effects of sulfur are suppressed, preferably even more effectively than Haynes 214. For this purpose, E214LC should preferably be produced using a clean production process.

In addition, E214LC contains low measured levels of hafnium (Hf), zirconium (Zr) and yttrium (Y) for sulfur (S) absorption. Because silicon (Si) has a beneficial catalytic effect on the selective oxidation of the protective oxide layer, silicon (Si) is also carefully included in the composition at low measured levels to avoid the risk of reduced oxidation resistance that may occur if the production process of the component proves to result in abnormally low levels of silicon (Si).

For E214LC, no preferential change to MC carbide is predicted, and in view of the low carbon (C) content inherited from Haynes214, it may not result in a significant improvement in wear resistance. However, the strengthening elements increase the hardness of the alloy, and thus increase the wear resistance relative to Haynes 214. In view of the increased gamma prime solvus, the wear resistance at higher temperatures is particularly improved.

In another embodiment, an increase in carbon (C) content to 0.15 wt% E214MC enables more carbides to be formed, further improving wear resistance, and hafnium is included at 1.0 wt% to combine additional carbon (C) into MC carbides. All carbides are currently predicted to be MC carbides at below 1273K, and some MC are predicted to be stable at below 873K. This strongly suggests a further improved abrasion resistance relative to E214 LC. The MC carbide level at 1273K was predicted to be 1.4mol%. The predicted aluminum activity was further increased relative to E214 LC. The predicted gamma 'curve only slightly changes compared to the gamma' curve of E214 LC.

In yet another embodiment, an increase in carbon (C) content to 0.25% of E214HC enables more MC carbide formation relative to E214MC, thereby further improving wear resistance. For this purpose, hafnium is added to 2.0 wt.% to combine additional carbon (C) into MC carbide. All carbides were predicted to be MC carbides at below 1273K, and some MC were predicted to be stable at below 873K. The MC carbide level at 1273K was predicted to be 2.4mol%. This strongly suggests an improved wear resistance. The predicted aluminum (Al) activity was further improved relative to E214 MC. The predicted gamma ' curve is altered compared to the gamma ' curve of E214LC in the sense that the gamma ' solvus is reduced.

The nickel-based plate alloy of the present invention has the following composition (in wt.%):

6.0 to 12.0% cobalt (Co)

6.0 To 12.0% of iron (Fe)

14.0 To 18% chromium (Cr)

2.0 To 5.0% of tungsten (W)

4.0 To 5.5% of aluminum (Al)

2.0 To 3.5% tantalum (Ta)

0.03 To 0.3% of carbon (C)

0.005 To 0.03% of boron (B)

0.005% To 0.03% zirconium (Zr)

0.005% To 0.5% silicon (Si)

Up to 2.0% molybdenum (Mo)

Up to 0.2% titanium (Ti)

Up to 2.0 wt.% manganese (Mn)

As well as nickel (Ni) and unavoidable impurities.

Both cobalt (Co) and iron (Fe) are included at least 6.0 wt.% to ensure that their combination beneficially affects the aluminum (Al) partitioning to keep gamma' levels moderate and significantly contributes to high aluminum (Al) activity. Both of them have an upper limit of 12.0% by weight to avoid excessive formation of brittle phases.

Chromium (Cr) is included at a level that provides good hot corrosion resistance and contributes to high aluminum activity, but the upper limit is 18.0 wt% to avoid excessive formation of brittle phases.

Tungsten (W) is included at least 2.0 wt% to provide strengthening of the gamma matrix, but at an upper limit of 5.0 wt% to avoid excessive formation of brittle phases.

Aluminum (Al) is included at least 4.0 wt.% to achieve high aluminum activity and effective levels of gamma prime particles. The upper limit is 5.5% by weight to avoid excessive formation of brittle phases.

Tantalum (Ta) is included at least 2.0 wt.% to provide reinforcement of the gamma prime particles. The upper limit is 3.5 wt% to avoid excessive gamma' formation.

Carbon (C) is contained at least 0.03 wt% to increase grain boundary strengthening, and an upper limit of 0.3 wt% to ensure formability and overall ductility is useful.

Boron (B) and zirconium (Zr) are included in the ranges typical for most high Wen Jiyu nickel alloys and are used in combination with carbon (C) for grain boundary strengthening. Zirconium (Zr) is also part of the sulfur absorbing formulation with hafnium (Hf) and yttrium (Y).

Silicon (Si) is included at least 0.005 wt% to help accelerate the selective oxidation of protective Cr ₂O₃ and protective Al ₂O₃, but the upper limit is 0.5 wt% to avoid embrittlement of grain boundaries.

Rare earths such as yttrium (Y), scandium (Sc), lanthanoids and actinoids are combined with zirconium (Zr) and hafnium (Hf) in sulfur (S) absorbing formulations. Rare earth additions as low as 0.002 wt% may be effective, especially if a cleaning process is used, while exceeding 0.2 wt% may result in excessive formation of rare earth oxides inside the alloy.

Hafnium (Hf) is included at least 0.05 wt.% to increase sulfur absorbing formulation and has an upper limit of 3.0 wt.%.

Molybdenum (Mo) may supplement tungsten (W) as a matrix strengthening element. The upper limit thereof is 2.0% by weight, since a higher level may reduce hot corrosion resistance. [ Goldschmidt ] "D.Goldschmidt 'SINGLE CRYSTAL Blades', MATERIALS FOR ADVANCED POWER ENGINEERING, section 1, 1994" teaches that the hot corrosion resistance of SC16 (16 wt% Cr,3 wt% Mo) is significantly reduced relative to IN738LC (16 wt% Cr,1.8 wt% Mo).

Although titanium (Ti) is detrimental to oxidation resistance at high temperatures because it increases the permeability of the Al ₂O₃ layer, its inclusion at low levels can facilitate sulfur absorption. It may also be used as a sacrificial element so that a Ti nitride is formed instead of an Al nitride.

Manganese (Mn) is generally present in sheet alloys, especially those that are also used as weld filler materials, see, for example, the C-263 composition in Table 1. It is sometimes considered to be beneficial to oxidation resistance and hot corrosion resistance by acting as a sulfur absorber, especially for sulfur from external sources. The expression here is sometimes reasonable in view of the wide range of etchant compositions. It is also sometimes considered to be beneficial for solderability. The expression here is sometimes reasonable in view of the wide range of welding processes and welding parameters utilized. The upper limit is 2% by weight to avoid embrittlement.

An increase in MC carbide levels will inevitably limit formability and to some extent oxidation resistance as well, so embodiments with high levels of MC carbide in structures such as, but not limited to, such baffle seals that may be susceptible to wear but are not formed into complex shapes are preferred and typically have a lower risk of hot gas ingestion than, for example, seals between adjacent impellers and adjacent heat shields.

Embodiments optimized for oxidation resistance can be advantageously used for such sealing strips. When such a sealing strip is significantly bent, the person skilled in the art can adjust the preferred MC carbide level downwards.

Lanthanum (La) and yttrium (Y) are more expensive to use, but it is seen that improved oxidation resistance is provided in the internal repair alloy compared to the use of only one rare earth. Embodiments to be used for welding may also require that the composition adjustment ."J.B.Wahl,K.Harris'Advances in Single CrystalSuperalloys-Control of Critical Elements',Parsons Conf.Glascow,2007" by those skilled in the art, as required by the particular welding process, teaches that hafnium is more effective to use with lanthanum and yttrium than with hafnium and lanthanum or hafnium and yttrium in the cyclic oxidation test of CMSX-4.

Claims

1. A nickel-based superalloy,

Includes (in weight percent):

6.0% to 12.0% cobalt (Co)

6.0% to 12.0% iron (Fe)

14.0% to 18% chromium (Cr)

Up to 2.0% molybdenum (Mo)

2.0% to 5.0% tungsten (W)

4.0% to 5.5% aluminum (Al)

2.0% to 3.5% tantalum (Ta)

Up to 0.2% titanium (Ti)

0.03% to 0.3% carbon (C)

0.005% to 0.03% boron (B)

Zirconium (Zr) of 0.005% to 0.03%

0.005% to 0.5% silicon (Si)

The total content of yttrium (Y), scandium (Sc), lanthanides and actinides is 0.002% to 0.2%, and the total content of hafnium (Hf) is 0.05% to 3.0%.

Up to 2.0% manganese (Mn)

Nickel (Ni), especially the remainder being nickel (Ni),

And unavoidable impurities.

2. The nickel-based superalloy according to claim 1,

Includes (by weight %)

7.0% to 9.0% cobalt (Co)

7.0% to 9.0% iron (Fe)

15.0% to 17.0% chromium (Cr)

2.5% to 3.5% tungsten (W)

4.2% to 4.8% aluminum (Al)

2.5% to 3.5% tantalum (Ta)

0.03% to 0.07% carbon (C)

Boron (B) of 0.007% to 0.013%

Zirconium (Zr) content: 0.007% to 0.013%

0.007% to 0.015% silicon (Si)

0.005% to 0.03% yttrium (Y)

0.07% to 0.13% hafnium (Hf).

3. The nickel-based superalloy according to claim 2, comprising (in weight percent)

8.0% cobalt (Co)

8.0% iron (Fe)

16.0% chromium (Cr)

3.0% tungsten (W)

4.5% aluminum (Al)

3.0% tantalum (Ta)

0.05% carbon (C)

0.01% boron (B)

0.01% zirconium (Zr)

0.01% silicon (Si)

0.015% yttrium (Y)

0.1% hafnium (Hf).

4. The nickel-based superalloy of claim 1, comprising (in weight percent)

7.0% to 9.0% cobalt (Co)

7.0% to 9.0% iron (Fe)

15.0% to 17.0% chromium (Cr)

2.5% to 3.5% tungsten (W)

4.2% to 4.8% aluminum (Al)

2.5% to 3.5% tantalum (Ta)

0.12% to 0.18% carbon (C)

Boron (B) of 0.007% to 0.013%

Zirconium (Zr) content: 0.007% to 0.013%

0.007% to 0.015% silicon (Si)

0.005% to 0.03% yttrium (Y)

0.9% to 1.1% hafnium (Hf).

5. The nickel-based superalloy of claim 4, comprising (in weight percent)

8.0% cobalt (Co)

8.0% iron (Fe)

16.0% chromium (Cr)

3.0% tungsten (W)

4.5% aluminum (Al)

3.0% tantalum (Ta)

0.15% carbon (C)

0.01% boron (B)

0.01% zirconium (Zr)

0.01% silicon (Si)

0.015% yttrium (Y)

1.0% Hafnium (Hf)

6. The nickel-based superalloy of claim 1, comprising (in weight percent)

7.0% to 9.0% cobalt (Co)

7.0% to 9.0% iron (Fe)

15.0% to 17.0% chromium (Cr)

2.5% to 3.5% tungsten (W)

4.2% to 4.8% aluminum (Al)

2.5% to 3.5% tantalum (Ta)

0.22% to 0.28% carbon (C)

Boron (B) of 0.007% to 0.013%

Zirconium (Zr) content: 0.007% to 0.013%

0.007% to 0.015% silicon (Si)

0.005% to 0.03% yttrium (Y)

1.9% to 2.1% of hafnium (Hf).

7. The nickel-based superalloy of claim 6, comprising (in weight percent)

8.0% cobalt (Co)

8.0% iron (Fe)

16.0% chromium (Cr)

3.0% tungsten (W)

4.5% aluminum (Al)

3.0% tantalum (Ta)

0.25% carbon (C)

0.01% boron (B)

0.01% zirconium (Zr)

0.01% silicon (Si)

0.015% yttrium (Y)

2.0% hafnium (Hf).

8. The nickel-based superalloy of claim 1, comprising (in weight percent):

7.0% to 9.0% cobalt (Co)

7.0% to 9.0% iron (Fe)

15.0% to 17.0% chromium (Cr)

2.5% to 3.5% tungsten (W)

4.2% to 4.8% aluminum (Al)

2.5% to 3.5% tantalum (Ta)

0.03% to 0.07% carbon (C)

Boron (B) of 0.007% to 0.013%

Zirconium (Zr) content: 0.007% to 0.013%

0.007% to 0.015% silicon (Si)

0.003% to 0.02% yttrium (Y)

Lanthanum (La) ranging from 0.003% to 0.02%

0.07% to 0.13% hafnium (Hf).

9. The nickel-based superalloy of claim 8, comprising (in weight percent)

8.0% cobalt (Co)

8.0% iron (Fe)

16.0% chromium (Cr)

3.0% tungsten (W)

4.5% aluminum (Al)

3.0% tantalum (Ta)

0.25% carbon (C)

0.01% boron (B)

0.01% zirconium (Zr)

0.01% silicon (Si)

0.01% yttrium (Y)

0.01% Lanthanum (La)

0.1% hafnium (Hf).

10. The nickel-based superalloy according to any one of claims 1 to 9, wherein at least two rare earth elements are intentionally utilized, and wherein both are present in an amount of at least 0.002% by weight.

11. A powder having a composition according to any of the aforementioned alloys.

12. A method for repairing or rebuilding a component,

The alloy used is any one of claims 1 to 10 or the powder according to claim 11.

13. The method according to claim 12,

This involves the application of printing or casting methods.