Turbine airfoil components containing ceramic-based materials and processes therefor

摘要

Hybrid turbine airfoil components containing a ceramic material, in which detailed features of the components are formed of materials other than ceramic materials. The components include a first component formed of a ceramic-based material and a second component formed of a metallic material. The first component comprises an airfoil portion and a nub, and the second component is separately formed and attached to the first component by casting the metallic material around the nub of the first component. The second component includes a platform portion between the airfoil portion and the nub of the first component and a dovetail portion on the nub of the first component. Each of the platform and dovetail portions has at least one off-axis geometric feature that results in the second component having a more complex geometry than the first component.

主权项

1. A turbine airfoil component of a gas turbine engine, the airfoil component being a turbine blade comprising:
a first subcomponent comprising an airfoil portion and a nub, the nub comprising a base that has outer surfaces, the outer surfaces of the base defining a cross-section of the base that is wider than a region of the nub adjacent the airfoil portion, the first subcomponent being formed of a ceramic-based material and the airfoil portion and the nub being a unitary piece of the ceramic-based material; and a second subcomponent comprising a casting formed and attached to the first subcomponent by casting a molten metallic material in-situ around the nub of the first subcomponent, the second subcomponent comprising a platform portion between the airfoil portion and the nub of the first subcomponent and a dovetail portion on the nub of the first subcomponent and adapted for anchoring the airfoil component to a turbine disk, each of the platform portion and the dovetail portion having at least one off-axis geometric feature that results in the second subcomponent having a more complex geometry than the first subcomponent, the dovetail portion of the second subcomponent having: a shank casing that completely encases the nub so that the region of the nub adjacent the airfoil portion is covered by a nonconformal portion of the shank casing and so that the base of the nub is entirely covered by a conformal portion of the shank casing having an exterior surface that conforms to the outer surfaces of the base, the off-axis geometric feature of the dovetail portion comprising a first set of oppositely-disposed tangs that are exclusively defined by the nonconformal portion of the shank casing and protrude from the region of the nub adjacent the airfoil portion, the off-axis geometric feature of the dovetail portion comprising a second set of oppositely-disposed tangs that are exclusively defined by the base of the nub and by the conformal portion of the shank casing thereon, the conformal portion of the shank casing defining a pressure face on each of the second set of oppositely-disposed tangs.