Blade outer air seal

• US 8,303,247 B2
• Filed: 11/27/2007
• Issued: 11/06/2012
• Est. Priority Date: 09/06/2007
• Status: Expired due to Fees

• Current Assignee: United Technologies Corporation (Rtx Corporation)
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Schlichting, Kevin W., Freling, Melvin, Dierberger, James A.
• Primary Examiner(s): Look, Edward
• Assistant Examiner(s): ELLIS, RYAN H
• Application Number:
  US11/945,285
• Publication Number:
  US 20090169368A1
• Time in Patent Office: 1,806 Days
• Field of Search: 415/170.1, 415/173.1, 415/174, 415/200, 416/174
• US Class Current: 415/173.1
• 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 inner diameter (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 pre-formed ceramic member;

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

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.

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

the projections are posts.

3. 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.

4. 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.

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

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

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

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

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

the inboard layer consists essentially of mullite; and

the outboard layer consists essentially of 7YSZ.

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

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

9. 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.

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

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

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

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

12. 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.

13. 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.

14. 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.

15. 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 outer diameter (OD) face;

a transversely concave inner diameter (ID) face;

a forward end;

an aft end;

a first circumferential edge;

a second circumferential edge; and

at least one engagement feature along the OD face of the ceramic member; and

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

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 element to leave porosity and the second sacrificial element to leave the engagement feature.

16. The method of claim 15 wherein the securing comprises:

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

17. The method of claim 16 wherein:

the forming of the mating feature comprises brazing.

18. The method of claim 15 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.

19. The method of claim 18 wherein:

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

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

a metallic member;

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

a transversely concave inner diameter (ID) face;

an outer diameter (OD) face;

at least one engagement feature along the OD face;

a forward end;

an aft end; and

first and second circumferential edges; and

a braze extending from the metallic member into the engagement feature.