METHOD FOR MANUFACTURING A TITANIUM ALUMINIDE COMPONENT WITH A DUCTILE CORE AND CORRESPONDINGLY MANUFACTURED COMPONENT

Abstract

A method is provided, for manufacturing a component of a turbomachine, in particular a blade, in which initially a shell (6) including an interior cavity (7) corresponding to the outer contour of the component is manufactured from an intermetallic TiAl material, and subsequently a Ti alloy in powder form is filled into the cavity, and the cavity with the filled-in Ti alloy powder is tightly sealed, the tightly sealed shell (6) including the enclosed titanium alloy powder being subsequently processed into a component of the turbomachine using hot isostatic pressing. Alternatively, the invention relates to a method for generatively manufacturing a component including a shell made from a TiAl alloy and a core made from a Ti alloy. In addition, the invention relates to a correspondingly manufactured component.

Claims

1. A method for manufacturing a component of a turbomachine, comprising the steps of: initially manufacturing a shell including an interior cavity corresponding to an outer contour of the component from an intermetallic TiAl material; subsequently filling a Ti alloy in powder form into the cavity; sealing the cavity with the filled-in Ti alloy powder to define a tightly sealed shell with enclosed Ti alloy powder; and subsequently processing the tightly sealed shell with the enclosed Ti alloy powder into the component of the turbomachine using hot isostatic pressing.

2. The method as recited in claim 1 wherein the component is a blade.

3. The method as recited in claim 1 wherein the Ti alloy powder contains a proportion of high-melting point foreign particles.

4. The method as recited in claim 3 wherein the high-melting point foreign particles are TiAl particles.

5. The method as recited in claim 3 wherein the proportion of high-melting point foreign particles in the Ti alloy powder lies in the range of 2 through 10 vol. %.

6. The method as recited in claim 5 wherein the proportion of high-melting point foreign particles in the Ti alloy powder lies in the range of 8 through 15 vol. %.

7. The method as recited in claim 1 wherein a proportion of fine powder particles with grain sizes smaller than 15 m in the Ti alloy powder is less than or equal to 5 vol. %.

8. The method as recited in claim 7 wherein the proportion of fine powder particles with grain sizes smaller than 15 m in the Ti alloy powder is less than or equal to 1 vol. %.

9. The method as recited in claim 1 wherein the shell is manufactured using a generative method building up the shell in layers.

10. The method as recited in claim 9 wherein the generative method is laser beam melting or electron beam melting.

11. The method as recited in claim 10 wherein the generative method is selective laser beam melting.

12. The method as recited in claim 1 wherein the cavity including the filled-in Ti alloy powder is sealed by fusing the filled-in Ti alloy powder.

13. The method as recited in claim 12 wherein the fusing is by electron beam or laser beam melting.

14. The method as recited in claim 1 wherein the hot isostatically pressed component is subjected to a heat treatment.

15. The method as recited in claim 1 wherein at least one of the steps of the method is carried out under vacuum conditions.

16. The method as recited in claim 1 wherein the hot isostatically pressed component is subjected to a finishing operation for exact dimensioning or surface setting.

17. A component of a turbomachine the component, the component comprising a shell made from an intermetallic TiAl-alloy, the shell surrounding a core formed from a Ti alloy with a higher ductility than the intermetallic TiAl alloy of the shell.

18. A component of a turbomachine the component manufacturing according to the method of claim 1, the component comprising a shell made from an intermetallic TiAl-alloy, the shell surrounding a core formed from a Ti alloy with a higher ductility than the intermetallic TiAl alloy of the shell.

19. The component as recited in claim 17 wherein the component is a blade.

20. The component as recited in claim 17 wherein the core has a structure with intermetallic TiAl particles embedded between crystalline particles of the Ti alloy.

21. The component as recited in claim 17 wherein an interface between the core and the shell has a three-dimensional surface structure.

22. The component as recited in claim 17 wherein the component is a blade, only a vane area having a core made from a Ti alloy surrounded by a TiAl shell, whereas a root area of the blade and the shell are constructed completely from a TiAl-alloy.

23. A method for manufacturing a component of a turbomachine, the method comprising the steps of: manufacturing a shell with an outer contour of the component manufactured in layers from an intermetallic TiAl material using a generative manufacturing method, and manufacturing a core, surrounded by the shell, from a Ti alloy in powder form.

24. The method as recited in claim 23 wherein the component is a blade.

25. The method as recited in claim 24 wherein the Ti alloy powder contains a proportion of high-melting point foreign particles.

26. The method as recited in claim 25 wherein the high-melting point foreign particles are TiAl particles.

27. The method as recited in claim 25 wherein the proportion of high-melting point foreign particles in the Ti alloy powder lies in the range of 2 through 10 vol. %.

28. The method as recited in claim 27 wherein the proportion of high-melting point foreign particles in the Ti alloy powder lies in the range of 8 through 15 vol. %.

29. The method as recited in claim 23 wherein a proportion of fine powder particles with grain sizes smaller than 15 m in the Ti alloy powder is less than or equal to 5 vol. %.

30. The method as recited in claim 29 wherein the proportion of fine powder particles with grain sizes smaller than 15 m in the Ti alloy powder is less than or equal to 1 vol. %.

31. The method as recited in claim 23 wherein the shell is manufactured using a generative method building up the shell in layers.

32. The method as recited in claim 31 wherein the generative method is laser beam melting or electron beam melting.

33. The method as recited in claim 32 wherein the generative method is selective laser beam melting.

34. The method as recited in claim 23 wherein the cavity including the filled-in Ti alloy powder is sealed by fusing the filled-in Ti alloy powder.

35. The method as recited in claim 34 wherein the fusing is by electron beam or laser beam melting.

36. The method as recited in claim 23 wherein the shell is subjected to a heat treatment.

37. The method as recited in claim 23 wherein at least one of the steps of the method is carried out under vacuum conditions.

38. The method as recited in claim 23 wherein the shell is subjected to a finishing operation for exact dimensioning or surface setting.

39. A component of a turbomachine the component manufacturing according to the method of claim 23, the component comprising a shell made from an intermetallic TiAl-alloy, the shell surrounding a core formed from a Ti alloy with a higher ductility than the intermetallic TiAl alloy of the shell.

40. The component as recited in claim 39 wherein the core has a structure with intermetallic TiAl particles embedded between crystalline particles of the Ti alloy.

41. The component as recited in claim 39 wherein an interface between the core and the shell has a three-dimensional surface structure.

42. The component as recited in claim 39 wherein the component is a blade, only a vane area having a core made from a Ti alloy surrounded by a TiAl shell, whereas a root area of the blade and the shell are constructed completely from a TiAl-alloy.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0026] The appended drawings show purely schematically in:

[0027] FIG. 1 a longitudinal section through a semi-finished blade according to the present invention,

[0028] FIG. 2 a sectional view along cutting line A-A from FIG. 1,

[0029] FIG. 3 a sectional view along cutting line B-B from FIG. 1

[0030] FIG. 4 a sectional view along cutting line C-C from FIG. 1, and

[0031] FIG. 5 a longitudinal section through another specific embodiment of a semi-finished blade according to the present invention.

DETAILED DESCRIPTION

[0032] Additional advantages, characteristics, and features of the present invention are apparent in the subsequent detailed description of the exemplary embodiments. However, the present invention is not limited to these exemplary embodiments.

[0033] FIG. 1 shows a longitudinal section through a semi-finished blade of a turbomachine, for example of a gas turbine or an aircraft engine, as is used for the manufacturing of a corresponding blade according to the present invention.

[0034] Blade 1 includes a vane 2 and a blade root 3. An inner shroud 4 is arranged between blade root 3 and vane 2, whereas an outer shroud 5 is provided at the blade tip. Blade 1 is formed according to the present invention with an outer shell 6 which surrounds an inner core. In the semi-finished part shown in FIG. 1, a cavity 7 is formed which corresponds to the subsequent core of the blade.

[0035] In FIG. 1, shell 6 of blade 1 is apparent, which has been manufactured from a TiAl powder using a generative method. Laser beam melting or electron beam melting may be used as the generative method. Cavity 7, apparent inside of shell 6, may also be designated as powder channel 7, as the powder for the core of blade 1 is situated in cavity 7. Correspondingly, in a finished blade 1, the area of cavity 7 is filled by the core of blade 1. To fill in the powder for the core, an opening 8 is provided on the upper side of cavity 7 or powder channel 7, into which the powder may be filled to form the core of blade 1. In the depiction of FIG. 1, opening 8 is schematically sealed by a plurality of welded layers, which are generated by fusing the top layers of the powder in powder channel 7 and subsequently solidifying the melt in order to seal opening 8 airtight. The powder in the cavity or the powder channel is not shown for reasons of simplicity.

[0036] As is likewise apparent from FIG. 1, cavity 7 has a three-dimensional inner contour 9 with a plurality of depressions and projections, so that the core created from the powder filled into powder channel 7 is intermeshed with shell 6 by inner contour 9. This effectuates not only a good connection between the core and shell 6, but also an increase in the strength of shell due to inner contour 9.

[0037] FIGS. 2 through 4 show different sectional views along cutting lines A-A, B-B, and C-C. It is likewise apparent in the sectional views of FIGS. 2 through 4 how powder channel 7 or the subsequent core of blade 1 is formed.

[0038] In FIG. 2, which shows a sectional view in the area of upper shroud 5, opening 8 is apparent, via which the powder for the core of blade 1 may be filled into powder channel 7. Opening 8 is sealed after filling powder channel 7 by fusing the top powder layers.

[0039] FIG. 3 shows a cross section in the area of vane 2, surrounding shell 6 made from a titanium aluminide material and being clearly apparent, surrounds core 7 made from a high-temperature resistant titanium alloy.

[0040] A cross section through root 3 of blade 1 is shown in FIG. 4, powder channel 7 and thus the subsequent core of blade 1 having a powder channel expansion 10 or an expansion of the core at each of the ends, so that a higher proportion of the ductile titanium alloy is present at the end faces of the root, so that the ductility of blade root 3 is increased in the case of an impact in these areas.

[0041] Overall, it arises from FIGS. 1 through 4 that the cavity or powder channel 7 and correspondingly the core thus formed, which is surrounded by titanium aluminide shell 6, may be formed in different ways in order to achieve the desired and suitable strength of titanium aluminide shell 6 and the required ductility of the core.

[0042] FIG. 5 shows another example of a semi-finished blade 1, in which influence may be exerted on the property profile of blade 1 with respect to strength and ductility due to the configuration of shell 6 and cavity 7, in that, for example, titanium aluminide shell 6 is formed with reinforcements 11.

[0043] The method according to the present invention may now be carried out in such a way that initially shell 6 is formed from a titanium aluminide material, whereby a generative or additive method may be preferably used, in which powder material is fused in layers, so that, after the solidification of each melt, a solid semi-finished product is created corresponding to the material solidified in layers. In particular, arbitrary shapes may be implemented by generative methods, so that inner contour 9 of shell 6 may be advantageously configured in an arbitrary way.

[0044] After manufacturing shell 6, a powder material is filled into cavity 7 via opening 8, and subsequently opening 8 is tightly sealed, preferably by fusing the top powder layers of the filled-in powder. The sealing of opening 8 may, for example, be carried out similarly to the generative manufacturing of shell 6 by fusing with a high-energy beam, preferably an electron beam or a laser beam.

[0045] In the present invention, the filled-in powder material includes a titanium alloy, which has a higher ductility or a lower elastic modulus than the titanium aluminide material of shell 6. For example, the elastic modulus of the shell may lie in the range of 160 GPa, whereas the elastic modulus of the titanium alloy may lie in the range of 120 GPa.

[0046] In addition, a certain amount of titanium aluminide powder may be present in the powder material, which is filled into cavity 7 to form the core of blade 1, this titanium aluminide powder preventing grain growth during the subsequent heat treatment, during which the titanium alloy is present in the phase field, and pinning down the grain boundaries of the titanium alloy.

[0047] After filling the powder material into cavity 7 and sealing cavity 7 by fusing the powder material at opening 8, the semi-finished product thus generated is hot isostatically pressed and subjected to a suitable heat treatment. Thus, both the structure of the titanium aluminide material of shell 6 and the structure of the titanium alloy of the core of blade 1 may be set in the desired way. The shrinkage of the semi-finished product during the hot isostatic pressing may be taken into consideration beforehand by a larger dimensioning of shell 6.

[0048] Following the hot isostatic pressing and the heat treatment, the component or blade 1 thus generated may be finished, in that, for example, the surface receives a corresponding surface finish through a mechanical and/or electrochemical finishing, and the seal of opening 8 is mechanically or electrochemically subsequently machined.

[0049] Even though the present invention has been described in detail based on the exemplary embodiments, it is obvious for those skilled in the art that the present invention is not limited to these exemplary embodiments, but instead many variations are possible, in that individual features may be omitted or different combinations of features may be employed without departing from the scope of protection of the appended claims. In particular, the present invention includes all combinations of the individual features shown in the different exemplary embodiments, so that individual features, which are only described in connection with one exemplary embodiment may also be used with other exemplary embodiments, or combinations of individual features, which are not explicitly depicted, may also be used.

LIST OF REFERENCE NUMERALS

[0050] 1 Blade [0051] 2 Vane [0052] 3 Blade root [0053] 4 Inner shroud [0054] 5 Outer shroud [0055] 6 Shell [0056] 7 Powder channel or core [0057] 8 Opening or seal [0058] 9 Inner contour [0059] 10 Powder channel or core expansions [0060] 11 Shell reinforcements