Nickel-based alloys, powders, methods and components

Abstract

The present invention relates to a nickel-based alloy, which has at least the following alloying elements in weight %: cobalt (Co) 10.3 - 10.7, chromium (Cr) 9.8 - 10.2, tungsten (W) 9.3 - 9.7, aluminum (Al) 5.2 - 5.7, hafnium (Hf) 1.8 - 2.2, tantalum (Ta) 1.9 - 2.1, molybdenum (Mo) 0.4 - 0.6, with the balance including nickel and impurities.

Description

Technical Field

[0001] The invention relates to a nickel-based alloy, a powder, a method and a component. Background Art

[0002] Nickel-based alloys have high corrosion resistance and high temperature resistance, especially high creep strength at high temperatures. Alloys with the latter property are also referred to as so-called nickel-based superalloys. The alloys are used in particular in drive mechanism construction or in turbines for generating energy. Typically, components made of the described nickel-based alloys are manufactured by casting or sintering methods. Examples of corresponding alloys are given in DE 10 2017 007106 B4.

[0003] However, additive manufacturing methods using nickel-based alloys are also increasingly being used. An alloy that is very suitable for this is described in WO 2018 / 083065A1. Based on this alloy, the object of the present invention is to further increase the creep strength and to keep the microcrack formation at a low level or even to further reduce it. Summary of the invention

[0004] The object is achieved by the nickel-based alloy according to the invention, as well as by the powder according to the invention, the method according to the invention and the component according to the invention.

[0005] The nickel-based alloy according to the invention has at least the following alloying elements in % by weight:

[0006] Cobalt (Co) 10.3-10.7,

[0007] Chromium (Cr) 9.8-10.2,

[0008] Tungsten (W) 9.3-9.7,

[0009] Aluminum (Al) 5.2-5.7,

[0010] Hafnium (Hf) 1.8-2.2,

[0011] Tantalum (Ta) 1.9-2.1,

[0012] Molybdenum (Mo)0.4-0.6,

[0013] The rest consists of nickel and impurities.

[0014] Compared to the above-mentioned prior art, the present alloy differs in particular in that the hafnium content is increased, so that it is now between 1.8 weight percent and 2.2 weight percent. As a result, the alloy's tendency to solidification cracks is significantly reduced or completely prevented when the process parameters are adjusted. In contrast to alloys with a lower hafnium content, the targeted increase in the hafnium content additionally improves the mechanical properties by increasing the content of the so-called γ' phase. The tantalum content is also in the range of a slight increase compared to the prior art.

[0015] In a preferred embodiment of the present invention, the respective proportions of the alloying elements are again given in narrower percentage ranges and include at least the following:

[0016] Cobalt (Co) 10.55-10.65,

[0017] Chromium (Cr) 9.8-10.9,

[0018] Tungsten (W) 9.35-9.45,

[0019] Aluminum (Al) 5.35-5.45,

[0020] Hafnium (Hf) 1.85-1.95,

[0021] Tantalum (Ta) 1.95-2.05,

[0022] Molybdenum (Mo)0.4-0.6,

[0023] The rest consists of nickel and impurities.

[0024] Specific alloy compositions that have been tested as being particularly advantageous also lie within these narrower ranges. Based on the measurement of the composition, these ranges have the following individual proportions of the corresponding alloy components:

[0025] Cobalt (Co) 10.6,

[0026] Chromium (Cr) 9.8,

[0027] Tungsten (W) 9.4,

[0028] Aluminum (Al) 5.4,

[0029] Hafnium (Hf) 1.9,

[0030] Tantalum (Ta) 2.0,

[0031] Molybdenum (Mo)0.5,

[0032] Carbon (C) 0.06,

[0033] The rest is nickel and impurities.

[0034] In the case of this special alloy, it has been found that the tendency to microcracking is particularly low and that a high-temperature creep strength occurs which is significantly improved compared with the prior art.

[0035] The alloy compositions described so far are expressed such that, in addition to impurities, other constituents may also be present in small amounts. It has proven to be advantageous to select a carbon content that is between 0.04 and 0.08 in terms of weight percent.

[0036] Furthermore, it is expedient if the alloy contains boron and / or zirconium as a small proportion, preferably between 0.0025 wt % and 0.01 wt %.

[0037] The proportion of other alloy components of secondary significance which can also be considered impurities, namely silicon, manganese, phosphorus, sulfur, titanium, boron, zirconium, iron, copper, silver, lead, selenium, bismuth and magnesium, should each be less than 0.1% by weight, in particular less than 0.05% by weight and in the case of silicon preferably less than 0.02% by weight.

[0038] Another component of the present invention is a powder comprising the alloy according to the invention. The term "comprising" means that the powder consists essentially of the alloy in question, but can also have additives which have a positive effect on the additive manufacturing method. These can be specific binders or release agents. This means that the alloy itself and the powder produced therefrom can be used in particular for producing components by means of additive production methods.

[0039] In this context, a method for producing a component is also part of the invention, which method is carried out using an alloy according to the invention or a powder according to the invention. The method is preferably an additive manufacturing method, in particular a laser sintering method or a selective laser melting method, such as LPBF.

[0040] Another component of the invention is a component which comprises the alloy according to the invention or the powder according to the invention, wherein, neglecting minor additives, the component consists of the alloy. In this case, the term component is also to be understood as a semi-finished product which can be integrated into another component by further method steps and can then also have further material components in the final installed state.

[0041] It is particularly advantageous to use the alloy, the powder, the method and thus also the component in a turbine for generating electric power. In particular, in a gas turbine component. In principle, the invention can also be used in a turbine for driving a vehicle, in particular in an aircraft turbine.

Claims

1. A nickel-based alloy, the nickel-based alloy having at least the following alloy elements in weight %: Cobalt 10.3 - 10.7, Chromium 9.8 - 10.2, Tungsten 9.3 - 9.7, Aluminum 5.2 - 5.7, Hafnium 1.8 - 2.2, Tantalum 1.9 - 2.1, Molybdenum 0.4 - 0.6, wherein the remainder consists of nickel and impurities.

2. A nickel-based alloy, the nickel-based alloy having at least the following alloy elements in weight %: Cobalt 10.55 - 10.65, Chromium 9.8 - 10.9, Tungsten 9.35 - 9.45, Aluminum 5.35 - 5.45, Hafnium 1.85 - 1.95, Tantalum 1.95 - 2.05, Molybdenum 0.4 - 0.6, wherein the remainder consists of nickel and impurities.

3. The nickel-based alloy according to claim 1 or 2, the nickel-based alloy having at least the following alloy elements in weight %: Cobalt 10.6, Chromium 9.8, Tungsten 9.4, Aluminum 5.4, Hafnium 1.9, Tantalum 2.0, Molybdenum 0.5, Carbon 0.06, wherein the remainder is nickel and impurities.

4. The nickel-based alloy according to claim 1 or 2, characterized in that the nickel-based alloy additionally includes carbon having a share between 0.04 weight % and 0.08 weight %.

5. The nickel-based alloy according to claim 1 or 2, characterized in that the nickel-based alloy additionally includes boron and / or zirconium having a share between 0.0025 weight % and 0.01 weight %.

6. The nickel-based alloy according to claim 1 or 2, characterized in that the shares of silicon, manganese, phosphorus, sulfur, titanium, boron, zirconium, iron, copper, silver, lead, selenium, bismuth, and magnesium are each less than 0.1 weight %.

7. The nickel-based alloy according to claim 6, characterized in that the shares of silicon, manganese, phosphorus, sulfur, titanium, boron, zirconium, iron, copper, silver, lead, selenium, bismuth, and magnesium are each less than 0.05 weight %.

8. The nickel-based alloy according to claim 6, characterized in that the share of silicon is less than 0.02 weight %.

9. A powder, the powder comprising the nickel-based alloy according to any one of claims 1 to 8.

10. The powder according to claim 9, the powder comprising an additive for additive manufacturing, wherein the additive is a binder.

11. A method for manufacturing a component using the nickel-based alloy according to any one of claims 1 to 8 or the powder according to claim 9 or 10.

12. The method according to claim 11, characterized in that the method is an additive manufacturing method.

13. The method according to claim 12, characterized in that the method is selective laser sintering or selective laser melting.

14. A component, the component comprising the nickel-based alloy according to any one of claims 1 to 8.

15. A component, the component being composed of the nickel-based alloy according to any one of claims 1 to 8.

16. A component, the component being made of the powder according to claim 9 or 10.