BLADE OUTER AIR SEAL

• US 20090169368A1
• Filed: 11/27/2007
• Published: 07/02/2009
• Est. Priority Date: 09/06/2007
• Status: Active Grant

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Freling, Melvin, Schlichting, Kevin W., Dierberger, James A.
• Granted Patent: US 8,303,247 B2
• Time in Patent Office: Days
• US Class Current: 415/173.100
• CPC Class Codes: F01D 11/122 with erodable or abradable material blades having cutting or grinding tips F01D5/20
• CPC Class Codes: F05D 2240/11 Shroud seal segments
• CPC Class Codes: Y10T 29/49318 Repairing or disassembling
• CPC Class Codes: Y10T 29/49812 Temporary protective coating, impregnation, or cast layer

Abstract

A turbine engine blade outer air seal segment has a body having a base portion. The base portion has a transversely concave ID face, a forward end, an aft end, and first and second circumferential edges. The body has at least one mounting hook. The body comprises a metallic member and a ceramic member. The ceramic member and metallic member are joined along the base portion with the ceramic member inboard of the metallic member.

Claims

1. A turbine engine blade outer air seal segment comprising:

a body having;

a base portion having;

a transversely concave ID face;

a forward end;

an aft end; and

first and second circumferential edges; and

at least one mounting hook,

wherein;

the body comprises a metallic member and a ceramic member; and

the ceramic member and metallic member are joined along the base portion with the ceramic member inboard of the metallic member.

2. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member and metallic member are so joined by a plurality of metallic features interfitting with features in the ceramic member.

3. The turbine engine blade outer air seal segment of claim 2 wherein:

the metallic features are features of a casting.

4. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member and metallic member are so joined by a plurality of parallel rails on the metallic member in a plurality of parallel channels in the ceramic member.

5. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member and metallic member are so joined by a braze, the braze forming at least one projection interfitting with a complementary feature of the ceramic member.

6. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member and metallic member are so joined by a plurality of posts in a plurality of compartments in the ceramic member.

7. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member has a characteristic average thickness of at least 4 mm.

8. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member and metallic member are secured to each other by a macroscopic mechanical interfitting.

9. The turbine engine blade outer air seal segment of claim 1 wherein:

the ceramic member includes an outboard layer distinct from an inboard layer and having a different porosity.

10. The turbine engine blade outer air seal segment of claim 9 wherein:

each of the inboard layer and outboard layer represents at least 25% of a characteristic thickness of the ceramic member.

11. The turbine engine blade outer air seal segment of claim 9 wherein:

the inboard layer porosity is greater than the outboard layer porosity by at least 10% by volume porosity.

12. The turbine engine blade outer air seal segment of claim 9 wherein:

the inboard layer consists essentially of mullite; and

the outboard layer consists essentially of 7YSZ.

13. The turbine engine blade outer air seal segment of claim 9 wherein:

the inboard layer is of a different chemical composition than the outboard layer.

14. The turbine engine blade outer air seal segment of claim 1 wherein:

a median thickness of the ceramic member is 50-150% of a median thickness of the metallic member.

15. The turbine engine blade outer air seal segment of claim 1 wherein at least one location:

a thickness of the ceramic member is 50-150% of a thickness of the metallic member.

16. The turbine engine blade outer air seal segment of claim 1 wherein:

a median thickness of the ceramic member is 5-15 mm.

17. The turbine engine blade outer air seal segment of claim 1 further comprising:

at least one cover plate secured to the body to define at least one cavity and having a plurality of feed holes.

18. The turbine engine blade outer air seal segment of claim 1 wherein:

a plurality of outlet holes extend through the base portion to the ID face.

19. The turbine engine blade outer air seal segment of claim 1 wherein:

the at least one mounting hook includes;

at least one front mounting hook; and

at least one aft mounting hook.

20. A method for manufacturing a turbine engine blade outer air seal segment, the method comprising:

pre-forming a metallic body having;

a base portion having;

an ID face;

a forward end;

an aft end;

a first circumferential edge;

a second circumferential edge; and

at least one mounting hook;

forming a ceramic member having an OD face;

a transversely concave ID face;

a forward end;

an aft end;

a first circumferential edge;

a second circumferential edge; and

at least one mating feature along the ID face of the ceramic member; and

securing the ceramic member to the base portion ID face via the at least one engagement feature.

21. The method of claim 20 wherein the securing comprises:

forming at least one mating engagement feature on the face portion ID face cooperating with the engagement feature of the ceramic member.

22. The method of claim 21 wherein:

the forming of the mating feature comprises brazing.

23. The method of claim 20 wherein:

the forming of the body forms a mating feature on the base portion ID face; and

the assembling engages the mating feature with the engagement feature.

24. The method of claim 23 wherein:

the assembling comprises a shift of the mating feature along the engagement feature.

25. The method of claim 20 wherein:

the forming of the ceramic member comprises;

positioning a first sacrificial element in a mold;

positioning a second sacrificial element in the mold;

introducing a slurry to the mold;

hardening the slurry; and

destructively removing the first sacrificial material to leave porosity and the second sacrificial material to leave the engagement feature.

26. A turbine engine blade outer air seal segment comprising:

a metallic member; and

a pre-formed ceramic member joined to the metallic member inboard of the metallic member and having;

a transversely concave ID face;

a forward end;

an aft end; and

first and second circumferential edges.