PROCESS FOR PRODUCING A BLADE FOR A TURBOMACHINE

Abstract

The invention relates to a method for producing a blade (10) for a turbo machine, especially for an aviation engine, comprising at least the following steps: provision of a monocrystalline or polycrystalline basic body (14) with a supporting surface (16), and generative construction of a blade airfoil (12) of the blade (10) on the supporting surface (16) by layer-by-layer melting and/or sintering of a metallic and/or ceramic powder consisting of a first material (18) or material mixture; and separation of the blade airfoil (12) from the supporting surface (16) of the basic body (14) on a parting surface (20) of the blade airfoil (12).

A further aspect of the invention relates to a blade which is obtainable and/or is obtained by means of such a method.

Claims

1.-12. (canceled)

13. A method for producing a blade for a turbomachine, wherein the method comprises: providing a monocrystalline or polycrystalline basic body having a supporting surface, and generatively constructing a blade airfoil of the blade on the supporting surface by layer-by-layer melting and/or sintering of a metallic and/or ceramic powder of a first material or material mixture; and separating the blade airfoil from the supporting surface of the basic body on a parting surface of the blade airfoil.

14. The method of claim 13, wherein separating of the blade airfoil from the supporting surface of the basic body is carried out by erosion.

15. The method of claim 13, wherein the method further comprises generatively constructing a blade root of the blade on the parting surface of the blade airfoil and thereby connecting the blade root to the blade airfoil.

16. The method of claim 15, wherein the blade root, during generative construction thereof, is produced by layer-by-layer melting and/or sintering of a metallic and/or ceramic powder of a second material or material mixture which is different from the first material or material mixture.

17. The method of claim 15, wherein generative construction of the blade root is carried out in such a way that a polycrystalline structure is produced in the blade root.

18. The method of claim 15, wherein generative construction of the blade airfoil and/or of the blade root is carried out in a construction chamber which is exposed to a negative pressure.

19. The method of claim 15, wherein after connecting, the blade root and the blade airfoil are subjected to a common hot isostatic pressing.

20. The method of claim 15, wherein after connecting, the blade root and the blade airfoil are subjected to a common age-annealing.

21. The method of claim 13, wherein the first material or material mixture comprises a TiAl alloy.

22. The method of claim 21, wherein the TiAl alloy comprises, in addition to Ti and Al, one or more of Nb, Mo, W, Zr, V, Y, Hf, Si, C, Co.

23. The method of claim 21, wherein the TiAl alloy comprises from 30 to 42 at. % Al from 5 to 25 at. % Nb from 2 to 10 at. % Mo from 0.1 to 10 at. % Co or Zr from 0.1 to 1,5 at. % Si, from 0.1 to 0.5 at. % Hf, remainder Ti.

24. The method of claim 23, wherein the TiAl alloy comprises from 0.1 to 0.5 at. % Si.

25. The method of claim 21, wherein the TiAl alloy comprises from 30 to 35 at. % Al from 15 to 25 at. % Nb from 5 to 10 at. % Mo from 1 to 10 at. % Co or Zr, from 0.1 to 0.5 at. % Si from 0.1 to 0.5 at. % Hf, remainder Ti.

26. The method of claim 25, wherein the TiAl alloy comprises from 32 to 37 at. % Al.

27. The method of claim 25, wherein the TiAl alloy comprises from 5 to 10 at. % Co or Zr.

28. The method of claim 25, wherein the TiAl alloy comprises from 0.2 to 1.0 at. % Si.

29. The method of claim 26, wherein the TiAl alloy comprises from 5 to 10 at. % Co or Zr and from 0.2 to 1.0 at. % Si.

30. The method of claim 15, wherein the blade root comprises a second material or material mixture which comprises a TiAl alloy.

31. The method of claim 30, wherein the TiAl alloy is a γ-TiAl alloy.

32. A blade for a turbomachine, wherein the blade has been produced by the method of claim 13.

Description

[0028] Further features of the invention are obtained from the claims, the exemplary embodiments and also from the drawing. The features and feature combinations previously referred to in the description, and also the features and feature combinations which are referred to below in the exemplary embodiments and/or described alone are applicable not only in the respectively disclosed combination but also in other combinations or alone without departing from the scope of the invention. There are therefore also embodiments of the invention to be seen as being covered and disclosed which are not explicitly featured and explained in the exemplary embodiments but which originate from and are producible from the explained embodiments by means of separate feature combinations. There are also embodiments and feature combinations to be seen as being disclosed which therefore do not have all the features of an originally formulated independent claim. In this case, in the drawing:

[0029] FIG. 1 shows a schematic perspective view of a blade airfoil of a blade according to the invention, wherein the blade airfoil is generatively constructed on a basic body;

[0030] FIG. 2 shows a schematic perspective view of a blade root of the blade according to the invention, wherein the blade root is generatively constructed on a parting surface of the blade airfoil; and

[0031] FIG. 3 shows a schematic perspective view of the blade according to the invention.

[0032] FIG. 1 and FIG. 2 show individual method steps of a method according to the invention for producing a blade 10 for a turbomachine. The blade 10 is shown in full in FIG. 3 in this case.

[0033] FIG. 1 shows a generative construction of a blade airfoil 12 of the blade 10 on a presently polycrystalline basic body 14, Alternatively or additionally, the basic body 14 can also be monocrystalline and/or directionally solidified. The generative construction is carried out in this case by means of electron beam melting or selective laser sintering, wherein a first material 18, in the present case as a metallic powder, is sintered by means of an electron beam or laser beam 32. The electron beam/laser beam 32 is emitted by means of an electron beam gun or a laser 30. The blade airfoil 12 is constructed in this case on a supporting surface 16 of the basic body 14. The basic body 14 in the present case is designed as a beta TiAl crystal plate. As a result of the generative construction of the blade airfoil 12 on the monocrystalline or polycrystalline, preferably directionally solidified, basic body 14, an orientation of a beta phase of the basic body 14 can be impressed upon a material structure of the blade airfoil 12 during its production.

[0034] Following the construction of the blade airfoil 12, a separation, not shown here, of the blade airfoil 12 from the supporting surface 16 of the basic body 14 is carried out on a parting surface 20 of the blade airfoil 12. The separation of the blade airfoil 12 from the supporting surface 16 of the basic body 14 is preferably carried out in this case by means of erosion. This constitutes a particularly careful separation process, as a result of which the basic body 14 can be used for the construction of further blade airfoils.

[0035] FIG. 2 shows a further method step in which a generative construction of a blade root 22 of the blade 10 on the parting surface 20 of the blade airfoil 12, and in the process connecting of the blade root 22 to the blade airfoil 12, is carried out. For this purpose, the blade airfoil 12 is located in an inverted position in comparison to FIG. 1 so that a blade tip 13 is now directed downward in FIG. 2 in the plane of the drawing. Consequently, the parting surface 20 is directed upward. The parting surface 20 is covered with a metallic powder of a second material 24. The blade root 22 is constructed by means of layered sintering of the powder of the second material 24 using the electron beam/laser beam 32. The two materials 18, 24 are different from each other in this case.

[0036] The first material 18 is designed in the present case as a TiAl alloy which in addition to Ti and Al comprises molybdenum as a further alloy constituent. Alternatively, in addition to Ti and Al, niobium and molybdenum can also be included as further alloy constituents. The TiAl alloy can also comprise other elements, or a plurality of elements, from the group comprising Mo, W, Zr, V, Y, Hf, Si, C and Co in order to establish eventual material properties of the blade airfoil 22 as accurately as possible. In the present case, a γ-TiAl alloy is provided as the second material 24.

[0037] in many embodiments, the γ-TiAl alloy can be provided with the composition TNM Ti41 -44Al2-5Nb0.5-2Mo 0.01-0.5B, optionally +0.2-0.5Si 0.2-0.5C [at. %]. This specification of the composition is the customary nomenclature in the field of expertise, in which Ti is the balance and makes up the remainder of 100 at. % or—apart from unavoidable impurities—makes up the remainder of 100 at. %. The blade root 22 and the blade airfoil 12, after connecting, are subjected to a common high-temperature isostatic pressing—not additionally shown here—and also to a common age-annealing which follows this.

[0038] The described method is carried out in the present case entirely in a construction chamber 26 which is shown by dashed lines in FIG. 1 and FIG. 2, wherein the construction chamber 26 is exposed to a negative pressure P while the method is being conducted. Consequently, in addition to the generative production of the blade airfoil 12 on the basic body 14 the separation of the basic body 14 from the blade airfoil 12 and also the generative construction of the blade root 22 on the blade airfoil 12 in the construction chamber 26, which is exposed to the negative pressure P, is also carried out. This has the advantage that any oxidation processes during the overall production of the blade can be at least largely excluded. As a result of the negative pressure P, any oxidation processes during the method can be at least weakened.

[0039] FIG. 3 shows the blade 10 after its production. The blade 10 can now be joined by the blade root 22 for example to a rotor basic body, which is not additionally shown here. In the case of the joining, for example a plug-in connection between the blade root 22 and the rotor basic body can be produced.

[0040] The method is based on the knowledge that via a beta phase beta TiAl alloys solidifying from their melting temperature to room temperature have an even crystal orientation. As a result, the basic body 14 can be provided by this being produced by means of a drawing and separation process in a suitable furnace (for example in a Bridgman furnace). During this, a directional solidification of the crystals can be achieved on account of a controlled temperature gradient and crystal separator. Consequently, a directionally solidified monocrystalline or polycrystalline beta TiAl crystal or crystallite block can be grown as the basic body 14.

LIST OF REFERENCE NUMERALS

[0041] 10 Blade [0042] 12 Blade airfoil [0043] 13 Blade tip [0044] 14 Basic body [0045] 16 Supporting surface [0046] 18 First material [0047] 20 Parting surface [0048] 22 Blade root [0049] 24 Second material [0050] 26 Construction chamber [0051] 30 Electron beam gun/laser [0052] 32 Electron beam or laser beam