Sprayed Skin Turbine Component

• US 20110192024A1
• Filed: 02/05/2010
• Published: 08/11/2011
• Est. Priority Date: 02/05/2010
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Energy Incorporated (Siemens AG)
• Inventors: Allen, David B.
• Granted Patent: US 8,453,327 B2
• Time in Patent Office: Days
• US Class Current: 29/889.721
• CPC Class Codes: B23P 15/04 turbine or like blades from several pieces
• CPC Class Codes: F01D 5/147 Construction, i.e. structural features, e.g. of weight-saving hollow blades F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18
• CPC Class Codes: F05D 2230/21 by casting
• CPC Class Codes: F05D 2230/236 Diffusion bonding
• CPC Class Codes: F05D 2230/312 by plasma spraying
• CPC Class Codes: Y10T 29/49341 with cooling passage
• CPC Class Codes: Y10T 29/49343 Passage contains tubular insert

Abstract

Fabricating a turbine component (50) by casting a core structure (30), forming an array of pits (24) in an outer surface (32) of the core structure, depositing a transient liquid phase (TLP) material (40) on the outer surface of the core structure, the TLP containing a melting-point depressant, depositing a skin (42) on the outer surface of the core structure over the TLP material, and heating the assembly, thus forming both a diffusion bond and a mechanical interlock between the skin and the core structure. The heating diffuses the melting-point depressant away from the interface. Subsurface cooling channels (35) may be formed by forming grooves (34) in the outer surface of the core structure, filling the grooves with a fugitive filler (36), depositing and bonding the skin (42), then removing the fugitive material.

Claims

1. A process for fabricating a component, comprising:

forming an array of pits in an outer surface of a core structure;

forming a skin on the outer surface of the core structure, wherein skin mechanically interlocks with the pits; and

diffusion bonding the skin to the outer surface of the core structure.

2. The process of claim 1, comprising forming the pits with an average pit diameter of 20 to 100 microns, an average pit depth of 1.5 to 4 times the average pit diameter, and an average pit separation distance of 1 to 5 times the average pit diameter.

3. The process of claim 2, comprising depositing a transient liquid phase (TLP) material on the outer surface of the core structure prior to thermally spraying the skin onto the outer surface of the core structure over the TLP material.

4. The process of claim 3, wherein the TLP material is deposited using a thin film deposition process that deposits one or more layers of the TLP material, wherein each layer of the TLP material is less than 10 microns thick.

5. The process of claim 3, wherein the TLP material is deposited using a chemical vapor deposition process.

6. The process of claim 3, further comprising, after depositing the skin, maintaining the component in a temperature range of 1,080 to 1,150 degrees Celsius for one to four hours.

7. The process of claim 3, comprising sequentially first depositing the TLP material, and then forming the pits.

8. The process of claim 3, comprising sequentially first forming the pits, and then depositing the TLP material, wherein a final diameter of each pit including the TLP material is 20 to 100 microns.

9. The process of claim 3, comprising forming the pits, and then depositing the TLP material only within the pits.

10. The process of claim 2, further comprising, before depositing the skin, forming grooves in the outer surface of the core structure, filling the grooves with a fugitive filler, and, after depositing the skin, removing the fugitive filler to form subsurface cooling channels under and adjacent to the skin.

11. The process of claim 10, wherein the component is a turbine engine airfoil.

12. The process of claim 1, further comprising forming the pits by laser drilling that forms an ejecta ring surrounding each pit, not removing the ejecta rings, and depositing the skin over the ejecta rings.

13. A process for fabricating a turbine component, comprising:

casting a component core structure;

forming grooves in an outer surface of the core structure;

filling the grooves with a fugitive filler material;

forming pits with an average pit diameter of 20 to 100 microns in the outer surface of the core structure between the grooves;

depositing a transient liquid phase (TLP) material comprising a melting-point depressant on the outer surface of the core structure;

depositing a skin on the outer surface of the core structure over the TLP material, thereby forming an assembly;

heating the assembly, forming a diffusion bond interface between the skin and the core structure and diffusing the melting-point depressant away from the diffusion bond interface; and

removing the fugitive filler material, forming subsurface cooling channels under and adjacent to the skin.

14. The process of claim 13, comprising forming the pits with an average pit depth of 1.5 to 4 times the average pit diameter, and an average pit separation distance on at least a portion of the outer surface of the core structure of 1 to 5 times the average pit diameter.

15. The process of claim 14, comprising depositing the transient liquid phase (TLP) material on the outer surface of the core structure using a thin film deposition process, then thermally spraying the skin over at least said portion of the outer surface of the core structure and over the TLP material.

16. A component comprising:

a metal core structure; and

a metal skin bonded to the metal core structure by metal diffusion bonding and by mechanical interlocks comprising an array of pits with an average pit diameter of 20-100 microns in an outer surface of the core structure.

17. The component of claim 16, wherein the pits have an average separation distance, on at least a portion of the outer surface of the core structure, of 1-5 times the average pit diameter, and wherein the pits have an average depth of 1.5 to 4 times the average pit diameter.

18. The component of claim 16, further comprising ejecta surrounding each pit, with the metal skin being deposited over the ejecta and into the pits.

19. The component of claim 16, further comprising subsurface cooling channels in the core structure below and adjacent to the metal skin.