Turbine shroud

1. A turbine shroud comprising

an annular metallic carrier,

a one-piece ceramic blade track concentric with the annular metallic carrier, and

a cross-key connection formed between the annular metallic carrier and the one-piece ceramic blade track to locate the one-piece ceramic blade track relative to the annular metallic carrier, the cross-key connection including a plurality of keys and a plurality of corresponding keyways, the plurality of keys arranged to extend in a radial direction from the annular metallic carrier, and the plurality of corresponding keyways formed to extend in the radial direction into the one-piece ceramic blade track,

wherein the plurality of keyways extend along only a portion of an axial width of the one-piece ceramic blade track such that the cross-key connection is formed over only a portion of the axial width of the one-piece ceramic blade track, wherein the one-piece ceramic blade track includes a first portion having a first thickness and a second portion having a second thickness, the second thickness greater than the first thickness, and the plurality of corresponding keyways extend inwardly in the radial direction into the second portion of the one-piece ceramic blade track without extending inwardly in the radial direction into the first portion of the one-piece ceramic blade track, and wherein the one-piece ceramic blade track includes a third portion having an increasing thickness that interconnects the first portion and the second portion, and the plurality of corresponding keyways extend inwardly in the radial direction into the third portion of the one-piece ceramic blade track.

2. The turbine shroud of claim 1 , wherein the annular metallic carrier includes a connection flange adapted to be coupled to a turbine case, a connector extending inwardly in the radial direction from the connection flange and having a frustoconical shape, and a support band extending inwardly in the radial direction from the connection flange, and the plurality of keys extend inwardly in the radial direction from the support band.

3. The turbine shroud of claim 2 , wherein the support band has a forward side, arranged to face a combustor of a gas turbine engine, and an aft side, arranged to face away from a combustor of a gas turbine engine, and the plurality of keys extend axially from the forward side of the support band toward the aft side of the support band.

4. The turbine shroud of claim 1 , further comprising a retainer coupled to the annular metallic carrier and the one-piece ceramic blade track and arranged to engage an aft side of the annular metallic carrier and to engage an aft side of the one-piece ceramic blade track.

5. The turbine shroud of claim 1 , wherein each paired key and keyway is spaced equally around the circumference of the turbine shroud by a first circumferential distance, except for a locator pair thereof that is spaced a second circumferential distance, less than the first circumferential distance, from an adjacent pair thereof to locate the one-piece ceramic blade track relative to the annular metallic carrier in a single predetermined orientation.

6. A turbine shroud comprising

a round carrier having a first coefficient of thermal expansion, a one-piece blade track nested in the round carrier and having a second coefficient of thermal expansion, the second coefficient of thermal expansion being less than the first coefficient of thermal expansion, and

a cross-key connection formed between the round carrier and the one-piece blade track to locate the one-piece blade track relative to the round carrier, the cross-key connection including a plurality of keys and a plurality of corresponding keyways, the plurality of keys arranged to extend in a radial direction from the round carrier, and the plurality of corresponding keyways formed to extend in the radial direction into the one-piece blade track,

wherein the plurality of corresponding keyways extend along only a portion of an axial width of the one-piece blade track such that the cross-key connection is formed over only a portion of the axial width of the one-piece blade track, wherein the one-piece blade track includes a first portion having a first thickness, a second portion having a second thickness greater than the first thickness, and the plurality of corresponding keyways extend inwardly in the radial direction into the second portion of the one-piece blade track without extending inwardly in the radial direction into the first portion of the one-piece blade track, and wherein the one-piece blade track includes a third portion having an increasing thickness that interconnects the first portion and the second portion, and the plurality of corresponding keyways extend inwardly in the radial direction into the third portion of the one-piece blade track.

7. The turbine shroud of claim 6 , wherein the plurality of keys have the first coefficient of thermal expansion.

8. The turbine shroud of claim 7 , wherein the round carrier includes a connection flange adapted to be coupled to a turbine case, a connector arranged to extend inwardly in the radial direction from the connection flange and having a frustoconical shape, and a support band arranged to extend inwardly in the radial direction from the connector and connection flange, and the plurality of keys extend inwardly in the radial direction from the support band.

9. A method of locating a one-piece ceramic blade track relative to a metallic retainer, the method comprising

rotating the one-piece ceramic blade track to a single predetermined orientation relative to the metallic retainer,

nesting the one-piece ceramic blade track in a space formed by the metallic retainer so that the one-piece ceramic blade track is concentric with the metallic retainer, and

inserting a plurality of keys extending in a radial direction from the metallic carrier into a corresponding plurality of keyways formed in the one-piece ceramic blade track to thereby establish a cross-key connection between the one-piece ceramic blade track and the metallic carrier,

wherein the step of rotating the ceramic blade track to the single predetermined orientation relative to the metallic retainer includes the steps of (i) aligning at least two of the keys each spaced a first distance from a neighboring key with at least two of the keyways spaced to receive the at least two of the keys, and (ii) aligning at least one offset key spaced a second distance, different from the first distance, from a neighboring key with at least one corresponding offset keyway, wherein the at least one offset key and the at least one corresponding offset keyway are configured to only allow nesting of the one-piece ceramic blade track in the metallic retainer when the one-piece ceramic blade track is in the single predetermined orientation relative to the metallic retainer;

wherein the offset ceramic blade track includes a first portion having a first thickness, a second portion having a second thickness greater than the first thickness, and the plurality of keyways extend inwardly in the radial direction into the second portion of the one-piece ceramic blade track without extending inwardly in the radial direction into the first portion of the one-piece ceramic blade track, and

wherein the one-piece ceramic blade track includes a third portion having an increasing thickness that interconnects the first portion and the second portion, and the plurality of keyways extend inwardly in the radial direction into the third portion of the onepiece ceramic blade track.

10. The method of claim 9 , wherein the plurality of keyways extend along only a portion of an axial width of the one-piece ceramic blade track such that the cross-key connection is formed over only a portion of the axial width of the one-piece ceramic blade track.