# US 8,784,044 B2 · Turbine shroud segment

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- Number: US 8,784,044 B2
- Document ID: US8784044B2
- Status: Granted
- Kind: B2
- Application number: 13/222,013
- Filed: 2011-08-31
- Published: 2013-02-28
- Granted: 2014-07-22
- Earliest claimed: 2011-08-31
- Assignees: Pratt & Whitney Canada Corp.
- Applicants: Eric Durocher; Guy Lefebvre
- Inventors: Eric Durocher; Guy Lefebvre
- Web page: https://patentgrep.com/patent/US8784044B2

## CPC

- B22F 7/08: with one or more parts not made from powder {(B22F7/062 takes precedence)}
- B22F 3/225: {by injection molding}
- B22F 5/009: {of turbine components other than turbine blades (of turbine blades B22F5/04)}
- F01D 9/04: forming ring or sector
- F01D 25/246: {Fastening of diaphragms or stator-rings}
- F05D 2240/11: Shroud seal segments
- F05D 2260/201: by impingement of a fluid
- Y10T 29/49321: Assembling individual fluid flow interacting members, e.g., blades, vanes, buckets, on rotary support member
- Y10T 29/4998: Combined manufacture including applying or shaping of fluent material
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A turbine shroud segment is metal injection molded (MIM) about a core to provide a composite structure. In one aspect, the core is held in position in an injection mold and then the MIM material is injected in the mold to form the body of the shroud segment about the core. Any suitable combination of materials can be used for the core and the MIM shroud body, each material selected for its own characteristics. The core may be imbedded in the shroud platform to provide a multilayered reinforced platform, which may offer resistance against crack propagation.

## Claims

### Claim 1

A turbine shroud segment for a turbine shroud of a gas turbine engine, the segment comprising a metal injection molded (MIM) shroud body, said MIM shroud body including a platform having a hot gas path side surface and a back side surface, the platform being axially defined from a leading edge to a trailing edge in a direction from an upstream position to a downstream position of a hot gas flow passing through the turbine shroud, and being circumferentially defined between opposite lateral sides of the platform, and forward and aft hooks extending from the back side surface of the platform, said forward and aft hooks being axially spaced-apart from each other; and a core imbedded in the MIM shroud body, said core having a platform reinforcing section extending longitudinally along a circumferential direction of the platform between said hot gas path and back side surfaces.

### Claim 2 (depends on 1)

The turbine shroud segment defined in claim 1, wherein the core axially spans the platform between said forward and aft hooks, and wherein the core project into the forward and aft hooks.

### Claim 3 (depends on 1)

The turbine shroud segment defined in claim 1, wherein the core comprises a sheet metal member.

### Claim 4 (depends on 3)

The turbine shroud segment defined in claim 3, wherein the sheet metal member has a generally U-shaped section, including a forward leg extending into the forward hook of the MIM shroud body, an aft leg projecting into the aft hook of the MIM shroud body, and a web portion extending between said forward and aft legs, said web portion forming said substantially covering all of the surface area of the platform between the forward and aft hooks and forming at least in part said platform reinforcing section of the core.

### Claim 5 (depends on 1)

The turbine shroud segment defined in claim 1, wherein the core is a sheet metal member.

### Claim 6 (depends on 5)

The turbine shroud segment defined in claim 5, wherein the core is a perforated sheet metal member.

### Claim 7

A method of manufacturing a turbine shroud segment for a gas turbine engine, the method comprising: providing a metallic core; holding the metallic core in position in a metal injection mold; and metal injection molding (MIM) a shroud segment body about the metallic core to form a composite metallic component, including injecting a metal powder mixture into the injection mold to imbed the metallic core into the shroud segment body and subjecting the composite component to debinding and sintering operations.

### Claim 8 (depends on 7)

The method of claim 7, wherein the metallic core is provided in the form of a sheet metal member extending through a platform section of the shroud segment body, the sheet metal member providing and intermediate reinforcing layer between the opposed gas path and back side surfaces of the platform section.

### Claim 9 (depends on 7)

The method of claim 7, wherein providing the metallic core comprises shaping a sheet metal member to have a generally U-shaped section including a platform reinforcing section and front and rear hook reinforcing sections extending longitudinally from opposed ends of the platform reinforcing section.

### Claim 10 (depends on 7)

The method of claim 7, wherein providing a metallic core comprises forming the metallic core from a piece of perforated sheet metal.

### Claim 11 (depends on 7)

The method of claim 7, wherein the metal powder mixture is injected at a temperature inferior to about 250 degree Fahrenheit and a pressure inferior to about 100 psi.

### Claim 12

A shroud segment for a turbine shroud of a gas turbine engine, comprising a reinforced platform having a hot gas path side and a back side, the reinforced platform being axially defined from a leading edge to a trailing edge in a direction from an upstream position to a downstream position of a hot gas flow passing through a turbine section of the gas turbine engine, and being circumferentially defined between opposite lateral sides of the reinforced platform, the reinforced platform having a multilayer construction including an intermediate reinforcing layer comprising a sheet metal insert imbedded within the platform between said hot gas path side and back side.

### Claim 13 (depends on 12)

The shroud segment defined in claim 12, wherein the sheet metal insert is imbedded in metal injection molded material.

### Claim 14 (depends on 13)

The shroud segment defined in claim 13, wherein the sheet metal insert has a melting point equal to or inferior to that of the metal injection molded material.

### Claim 15 (depends on 12)

The shroud segment defined in claim 12, wherein the sheet metal insert has a plurality of perforations extending therethrough.

### Claim 16 (depends on 12)

The shroud segment defined in claim 12, wherein forward and aft hooks extend from the back side of the reinforced platform, and wherein the sheet metal insert has forward and aft legs respectively projecting into said forward and aft hooks.