Turbine engine alloys and crystalline orientations
A method is provided for engineering a single crystal cast gas turbine engine first component for cooperating with a second component. An at least local first operational stress on the first component is determined. The first operational stress has a first direction. A crystal orientation within the component or a physical configuration of the component is selected so that the first operational stress produces a desired engagement of the first component with the second component associated with either a negative Poisson's effect or high Poisson's effect in a second direction. Single crystal or highly textured iron- and nickel-base alloys enable one to use such effect in high temperature and/or corrosive environments.
1. An apparatus comprising:
a first member having a first slot extending in a first direction;
a second member; and
a metallic seal partially within the first slot and protruding from the first slot in a second direction to engage the second member,
wherein:
the seal has a crystalline microstructure oriented so that compression in the second direction causes contraction in a third direction essentially normal to the first and second directions;
the first slot has a shoulder;
the shoulder is formed along a convergence in the first slot; and
the seal has a lip engaging the shoulder.
2. The apparatus of claim 1 wherein:
the seal comprises a single crystal FCC substrate; and
a microstructure characterized by <1,1,0> direction essentially parallel to said second direction.
3. The apparatus of claim 1 wherein:
the first and second members are respective first and second blade platforms on a gas turbine engine.
4. The apparatus of claim 1 wherein:
the first and second members are essentially non-rotating relative to each other.
5. The apparatus of claim 1 wherein:
the second member has a second slot extending in the first direction; and
the seal is partially within the second slot.
6. The apparatus of claim 5 wherein:
the second slot has a second shoulder;
the seal has a second lip engaging the second shoulder; and
the second shoulder is formed along a convergence in the second slot.
7. The apparatus of claim 1 wherein the seal comprises:
a web having opposed parallel first and second sides;
a first protuberance along a first edge of the web; and
a microstructure characterized by:
a <1,1,0> direction essentially normal to the first edge and essentially parallel to the first and second sides.
8. The apparatus of claim 7 wherein the microstructure is of a nickel-based superalloy.
9. The apparatus of claim 7 wherein the first protuberance has first and second portions protruding from the first and second sides, respectively.
10. The apparatus of claim 9 wherein:
the first and second protrusions respectively engage shoulder portions of the first slot.
11. The apparatus of claim 7 further comprising:
a second protuberance along a second edge, opposite the first edge.
12. The apparatus of claim 7 wherein:
the first protuberance engages shoulder portions of the first slot.
13. The apparatus of claim 7 wherein:
the first protuberance is received in a recess in the first slot.
14. The apparatus of claim 1 wherein:
the shoulder is a first shoulder and the lip is a first lip;
the first slot has a second shoulder opposite the first shoulder; and
the seal has a second lip opposite the first lip and engaging the second shoulder.
15. The apparatus of claim 14 wherein:
the second member has a second slot extending in the first direction;
the seal is partially within the second slot;
the second slot has a third shoulder and a fourth shoulder opposite the third shoulder; and
the seal has a third lip and a fourth lip opposite the third lip, the third and fourth lips respectively engaging the third and fourth shoulders.