COMPOSITE MATERIAL FOR TURBO MACHINE APPLICATIONS AND CORRESPONDING METHOD

Abstract

A composite material for an application in a turbo machine having a metallic lattice and a ceramic matrix, wherein the metallic lattice pervades the ceramic matrix, thereby mechanically reinforcing the ceramic matrix against thermal and/or mechanical loads in an application of the composite material.

Claims

1.-10. (canceled)

11. A composite material for application in a turbo machine or a gas turbine, the composite material comprising: a metallic lattice, a ceramic matrix and internal cavities, wherein the metallic lattice pervades the ceramic matrix, thereby mechanically reinforcing the ceramic matrix against thermal and/or mechanical loads in an operation of the composite material.

12. The composite material according to claim 11, wherein the metallic lattice comprises a regular mesh-like structure which is configured to avoid peeling of parts from the composite material during thermal and/or mechanical loads in an operation of the composite material.

13. The composite material according to claim 11, wherein the metallic lattice comprises an irregular mesh-like structure which is configured to avoid peeling of parts from the composite material during thermal and/or mechanical loads in an operation of the composite material.

14. The composite material according to claim 11, wherein a coefficient of thermal expansion of the material of the metallic lattice and that one of the ceramic matrix is chosen to be similar.

15. The composite material according to claim 11, wherein the metallic lattice and the ceramic matrix are joined by positive locking to one another.

16. The composite material according to claim 11, wherein the metallic lattice is, to a predetermined extent, movable or slidable within or relative to the ceramic matrix, thus allowing some mutual movement of these components, due to different thermal expansion behavior.

17. A heat shield for a turbo machine or for a part of a combustion chamber of a gas turbine, comprising: the composite material according to claim 11.

18. A method to manufacture a composite material according to claim 11, comprising: a) additively manufacturing the metallic lattice, b) infiltrating the metallic lattice by a ceramic base material such that an inside of the metallic lattice is only partly filled such that cavities in the composite material remain which may, in an operation of the composite material, receive thermal expansion of the lattice material, and c) solidifying the infiltrated metallic lattice, wherein the ceramic base material is solidified, and the composite material is formed.

19. The method of claim 18, wherein additively manufacturing the metallic lattice comprises selective laser melting or electron beam melting.

20. The method of claim 18, wherein solidifying comprises sintering the infiltrated metallic lattice.

21. A computer program product comprising a non-transitory computer readable medium having executable program instructions thereon which are adapted to cause a data processing unit to design a geometry of the metallic lattice according to the method of claim 18, wherein the data processing unit uses computerized topology optimization, and wherein thermal expansion coefficients of the metallic lattice and the ceramic matrix are considered.

22. The computer program product of claim 21, wherein the data processing unit is in an additive manufacturing device that manufactures the metallic lattice according to the geometry.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further features, expediencies and advantageous refinements become apparent from the following description of the exemplary embodiment in connection with the Figures.

[0029] FIG. 1 shows a schematic view of a composite material according to the present invention.

[0030] FIG. 2 shows a schematic view of the composite material according to an alternative embodiment.

[0031] FIG. 3 shows a schematic indication of at least parts of a turbo machine, advantageously a gas turbine, comprising the composite material according to the present invention.

[0032] FIG. 4 shows a schematic flow chart of process steps according to the presented method.

DETAILED DESCRIPTION OF INVENTION

[0033] Like elements, elements of the same kind and identically acting elements may be provided with the same reference numerals in the figures.

[0034] FIG. 1 shows schematically a composite material 10. The composite material 10 is advantageously shown in a sectional view, indicating an inside of said material. The composite material 10 comprises a metallic lattice 1. The composite material 10 further comprises a ceramic matrix 2. The metallic lattice 1 pervades the ceramic matrix 2. In other words, the ceramic matrix 2 encloses or envelopes the metallic lattice 1. The composite material 10 composed of or comprising said metal and ceramic is advantageously configured such that the metallic lattice 1 reinforces or supports the ceramic matrix 2 in such a way, that the composite material 10 can withstand mechanical, thermal, and/or thermal mechanical loads as usual in the hot gas flow path of gas turbines without tendency for the ceramic to break or peel off. The metallic lattice 1 may be or comprise a regular, mesh-like structure. The dashed lines in the upper part of FIG. 1 indicate, that the metallic lattice advantageously pervades the ceramic matrix 2 in a spatial manner in order to serve its purpose for the whole component, in which said composite material 10 is actually applied (cf. FIG. 3).

[0035] Although the metallic lattice is shown in FIG. 1 only by means of crossed lines, it is expected that the indicated lattice structure, of course, comprises a certain extension, e.g. of several millimetres.

[0036] Indicated by numeral 4, the composite material 10 may comprise cavities. The cavities may particularly serve for providing spaces or play which may account for or receive a thermal expansion of parts of the composite material 10, advantageously the ceramic matrix. In other words, the cavities may adopt or receive material (thermally) expanding into these spaces as a consequence of a hot ambient, such as 1500 C., of a turbine gas flow.

[0037] Cavity 4a is particularly arranged in an area of an elongated part, such as a strut 11 or truss, of the metallic lattice 1.

[0038] Cavity 4b is shown arranged in an area of a cross-over 12 or intersection of struts of the metallic lattice 1.

[0039] Additionally or alternatively, cavity 4c may be provided in an area only taken by the ceramic lattice material 2. However, it is advantageous that the spaces or volume of the cavities contacts the metallic material.

[0040] Even though this is not explicitly indicated in FIG. 1, the metallic lattice 1 may be or comprise an irregular mesh-like structure, which may be expedient for a systematic or deliberate local strengthening of the composite material, e.g. at its surfaces which may be more prone to breakage or damage in a hot gas ambient.

[0041] In general, the component or composite material described herein as well as the described method (see below) stabilise or reinforce the described composite material in a way that a component comprising said material is less prone to cracking such that parts of the ceramic peel off or break or fall apart. This effect is particularly achieved by the described metallic lattice whichin other wordsmechanically holds the ceramic material (matrix) together.

[0042] FIG. 2 shows an alternative embodiment of the metallic lattice or as the case may be the composite material 10 according to the present invention. In contrast to the indication in FIG. 1, the metallic lattice 1 comprises sections of varying spatial extension. Particularly, the struts 11 forming connections between the corner points or cross-overs 12, comprise a smaller thickness or width as compared to the cross-overs 12. In other words, the corners 12 are embodied compact or a cube-like, further providing smaller thicknesses or extensions as compared to a length of the struts 11.

[0043] The length of the struts 11 may define the size of an according lattice cell of the metallic lattice 1.

[0044] Deviating from the indication of FIG. 2, the struts 11 and/or the cross-overs 12 may as well be star-shaped or dendritic or branched in order to functionally hold together the dissimilar materials of the composite.

[0045] Although this is also not explicitly indicated, the metallic lattice 1 may comprise or constitute a regular or irregular mesh of any perceivable lattice geometry, e.g. chosen from face-centred cubic (FCC), body-centred cubic (BCC), rhombic, and tetragonal, hexagonal, prism-like of further morphologies.

[0046] FIG. 3 shows a turbo machine 100, such as a turbine, particularly a gas turbine in a simplified schematic. Advantageously the turbine 100 is shown only in part. Reference numeral 30 indicates a hot gas flow path of said turbine. Said gas flow path 30 extends horizontally in FIG. 3. Said gas flow path is, advantageously, defined by components 20 made of or mainly comprising the described composite material 10. Said components 20 may constitute tiles of a combustion chamber of said turbine 100. To this effect, said tiles may be connected or fixed to one another by means of a tongue-groove-joint or sealing or the like, as shown in FIG. 3 at the interface between the components 20.

[0047] For instance, in an application of gas turbine, tiles of the combustion chamber constitute heat shields in order to withstand the harsh temperature environment during operation. As a consequence of the high temperatures, conventional tiles are prone to break or tend to deteriorate and crack or fall apart over time which may cause serious secondary damage to the turbine.

[0048] According to the present invention, the described composite material is applied for said heat shield tiles. Thereby, the probability of cracking, breaking or e.g. peeling off of parts of the ceramic can be significantly reduced, as compared to prior art heat shields.

[0049] FIG. 4 indicates method or process steps according to the present invention.

[0050] Particularly reference numeral a) indicates additively manufacturing the metallic lattice 1, e.g. by selective laser melting or electron beam melting, advantageously a powder bed-based manufacturing technique.

[0051] Further, reference numeral b) indicates an, e.g. computerized, topology optimization step, wherein thermal expansion coefficients of e.g. the metallic lattice 1 and the ceramic matrix 2 are considered, e.g. edited by a user of a corresponding data processing system (not explicitly indicated) or computer program.

[0052] Reference numeral c) indicates infiltrating the metallic lattice 1 by a ceramic powder such that an inside of the metallic lattice 1 is at least partly filled with the ceramic.

[0053] Still further, reference numeral d) indicates sintering the infiltrated metallic lattice 1, wherein the ceramic powder is solidified and the composite material 10 is formed.

[0054] By means of the provided cavities or spaces as described above, according to the design of the metallic lattice and with the aid of additive manufacturing as well as topology optimisation technology (see below), it may be achieved that differences in thermal expansion coefficients of the metallic lattice on one side and a ceramic material (matrix) on the other side may be compensated for such that stresses or tensions are advantageously not established in the composite material but e.g. balanced out.

[0055] The scope of protection of the invention is not limited to the examples given hereinabove. The invention is embodied in each novel characteristic and each combination of characteristics, which particularly includes every combination of any features which are stated in the claims, even if this feature or this combination of features is not explicitly stated in the claims or in the examples.