Methods for fabricating cast components with cooling channels

Patent metadata

Field	Value
Publication number	US-10933466-B2
Application number	US-201715595028-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	May 16, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A method for fabricating a cast component with a cooling channel is provided. The method includes forming a shell mold over a pattern-ceramic matrix composite (CMC) elongated core arrangement to define a cavity in the shell mold. The pattern-CMC elongated core arrangement includes a pattern-forming material with a CMC elongated core disposed therein. The pattern-forming material in the cavity is replaced with metal via a casting process to form the cast component with the CMC elongated core disposed therein defining the cooling channel. The CMC elongated core is removed from the cast component to open the cooling channel for fluid communication.

First claim

What is claimed is:

1. A method for fabricating a cast component having a cooling channel formed therein, the method comprising:
forming a shell mold over a pattern-ceramic matrix composite (CMC) elongated core arrangement to define a cavity in the shell mold, wherein the pattern-CMC elongated core arrangement comprises a pattern-forming material with a CMC elongated core disposed therein, the CMC elongated core being a monolithic tubular structure with a hollow passage formed therethrough and comprising a ceramic matrix reinforced with ceramic fibers, the ceramic fibers being present in an amount of from about 15 to about 50 volume percent (vol. %) of the CMC elongated core;
replacing the pattern-forming material in the cavity with metal via a casting process to form the cast component with the CMC elongated core disposed therein defining the cooling channel; and
removing the CMC elongated core from the cast component to open the cooling channel for fluid communication,
wherein the removing comprises advancing a wet etchant into the hollow passage to facilitate leaching out and/or etching of the CMC elongated core.

2. The method of claim 1 , further comprising forming the pattern-CMC elongated core arrangement comprising:
providing a pattern comprising the pattern-forming material and having a trench formed in the pattern-forming material; and
disposing the CMC elongated core in the trench.

3. The method of claim 2 , wherein the pattern has walls that define the trench, and wherein forming the pattern-CMC elongated core arrangement comprises filling remaining space in the trench between the CMC elongated core and the walls of the pattern with additional pattern-forming material.

4. The method of claim 3 , wherein the additional pattern-forming material is wax.

5. The method of claim 2 , wherein the CMC elongated core has an intermediate section, and wherein disposing the CMC elongated core in the trench comprises arranging the intermediate section of the CMC elongated core in the trench extending parallel to and/or offset from an adjacent outer surface of the pattern.

6. The method of claim 5 , wherein the CMC elongated core has a first end section and a second end section extending from opposing ends of the intermediate section, and wherein disposing the CMC elongated core in the trench comprises arranging the first and second end sections extending in generally opposing directions transverse to the adjacent outer surface of the pattern.

7. The method of claim 6 , wherein disposing the CMC elongated core in the trench comprises arranging the first end section protruding from the adjacent outer surface of the pattern and the second end section protruding from an opposing outer surface of the pattern that is arranged on a side opposite the adjacent outer surface.

8. The method of claim 7 , wherein forming the shell mold comprises forming the shell mold such that the first and second end sections are at least partially disposed in walls of the shell mold.

9. The method of claim 7 , wherein the pattern has an opening formed therethrough extending from the adjacent outer surface to the opposing outer surface, and wherein disposing the CMC elongated core comprises arranging the intermediate section of the CMC elongated core in the trench adjacent to the opening.

10. The method of claim 1 , wherein removing the CMC elongated core comprises leaching out or etching the CMC elongated core using a wet etching process.

11. The method of claim 1 , wherein fabricating the cast component comprises forming the cast component as a gas turbine engine component.

12. The method of claim 1 , wherein the pattern-forming material comprises wax or plastic material.

13. The method of claim 1 , further comprising forming the pattern-CMC elongated core arrangement comprising disposing the CMC elongated core in a pattern that comprises the pattern-forming material, wherein disposing the CMC elongated core in the pattern includes:
providing the CMC elongated core; and
forming and/or injecting the pattern over the CMC elongated core.

14. The method of claim 1 , wherein the method further comprises:
forming caps over ends of the CMC elongated core prior to forming the shell mold to close off the hollow passage; and
removing the caps from the ends of the CMC elongated core after forming the cast component to open the hollow passage.

15. The method of claim 1 , wherein the ceramic matrix comprises silicon carbide and the ceramic fibers comprise silicon carbide.

16. A method for fabricating a cast component having a cooling channel formed therein, the method comprising:
disposing a ceramic matrix composite (CMC) elongated core in a pattern that comprises a pattern-forming material, wherein the CMC elongated core is a monolithic tubular structure with a hollow passage formed therethrough and comprises a ceramic matrix reinforced with ceramic fibers, the ceramic fibers being present in an amount of from about 15 to about 50 volume percent (vol. %) of the CMC elongated core;
forming a shell mold over the pattern-CMC elongated core arrangement to define a cavity in the shell mold;
removing the pattern-forming material from the shell mold while leaving the CMC elongated core disposed in the cavity;
filling the cavity with molten metal and solidifying the molten metal to form the cast component with the CMC elongated core disposed therein defining the cooling channel; and
leaching out or etching the CMC elongated core to open the cooling channel in the cast component for fluid communication,
wherein caps are formed over ends of the CMC elongated core prior to forming the shell mold to close off the hollow passage,
wherein the caps are removed from the ends of the CMC elongated core after forming the cast component to open the hollow passage, and
wherein the leaching out or etching comprises advancing a wet etchant into the hollow passage to facilitate the leaching out or etching of the CMC elongated core.

17. The method of claim 16 , wherein disposing the CMC elongated core in the pattern comprises providing the CMC elongated core comprising ceramic fibers of alumina, mullite, silicon carbide, silicon nitride, zirconia, carbon, or combinations thereof.

18. The method of claim 16 , wherein disposing the CMC elongated core in the pattern comprises providing the CMC elongated core comprising the ceramic matrix that comprises silicon metal, silicon metal alloy, silicon carbide, silicon nitride, zirconia, alumina, or combinations thereof.

19. The method of claim 16 , wherein filling the cavity with molten metal and solidifying the molten metal comprises forming the cast component using a single crystal casting process.

20. The method of claim 19 , wherein forming the cast component comprises preheating the shell mold to a temperature of from about 1350 to about 1550° C. prior to filling the cavity with the molten metal.

21. The method of claim 16 , wherein the ceramic matrix comprises silicon carbide and the ceramic fibers comprise silicon carbide.

Assignees

• Rolls Royce Corp

Inventors

• Bulgrin Charles Alan
• Russo Carl R
• Kush Matthew T

Classifications

• B22C7/00

  Patterns; Manufacture thereof so far as not provided for in other classes · CPC title

• B22C1/00

  Compositions of refractory mould or core materials; Grain structures thereof (refractory materials in general C04B35/00); Chemical or physical features in the formation or manufacture of moulds · CPC title

• B22D21/005

  with high melting point, e.g. Be 1280 degrees C, Ti 1725 degrees C · CPC title

• B22D27/04

  Influencing the temperature of the metal, e.g. by heating or cooling the mould · CPC title

• F05D2300/10

  Metals, alloys or intermetallic compounds · CPC title