Method of forming composite components with cavities
A method of forming a composite component includes laying up a plurality of composite plies around a mandrel assembly to form a composite ply core. The mandrel assembly includes a mandrel having an inner structural body and an outer release layer. The mandrel is configured to form a cavity in the composite ply core. The method also includes processing the composite ply core containing the mandrel assembly to compact the plurality of composite plies together. Further, the method includes removing the mandrel assembly from the composite ply core to form the cavity. Further, removing the mandrel assembly from the composite ply core includes melting out the inner structural body and removing the outer release layer after melting out the inner structural body.
1 . A method of forming a composite component, the method comprising:
laying up a plurality of composite plies around a mandrel assembly to form a composite ply core, the mandrel assembly comprising a mandrel having an inner structural body and an outer release layer, the mandrel configured to form a cavity in the composite ply core;
processing the composite ply core containing the mandrel assembly to compact the plurality of composite plies together; and
removing the mandrel assembly from the composite ply core to form the cavity, wherein removing the mandrel assembly from the composite ply core comprises melting out the inner structural body and removing the outer release layer after melting out the inner structural body.
2 . The method of claim 1 , further comprising forming the mandrel to have a shape corresponding to a shape of the cavity.
3 . The method of claim 2 , wherein forming the mandrel further comprises:
manufacturing a metal alloy to form the inner structural body; and
coating the inner structural body with an impervious non-metallic material to form the outer release layer onto the inner structural body.
4 . The method of claim 3 , wherein the metal alloy has a melting temperature below a melting temperature of the outer release layer.
5 . The method of claim 3 , wherein the impervious non-metallic material is a polymeric material comprising at least one of silicone, polytetrafluoroethylene, or sol-gel.
6 . The method of claim 3 , wherein coating the inner structural body with the impervious non-metallic material to form the outer release layer onto the inner structural body further comprises utilizing at least one of injection molding, dip coating, spraying, or wrapping to coat the inner structural body with the impervious non-metallic material to form the outer release layer.
7 . The method of claim 1 , wherein processing the composite ply core containing the mandrel assembly to compact the plurality of composite plies together forms a green state core, and further comprising:
wrapping one or more additional composite plies around the green state core to form an outer enclosure; and
processing the green state core and the outer enclosure to form the composite component.
8 . The method of claim 7 , further comprising autoclaving the composite ply core.
9 . The method of claim 7 , wherein processing the green state core and the outer enclosure comprises:
after removing the mandrel assembly, autoclaving the green state core and the outer enclosure to form an autoclaved body;
firing the autoclaved body to burn out the composite plies and form a fired body; and
densifying the fired body to form the composite component.
10 . The method of claim 7 , wherein processing the green state core and the outer enclosure comprises:
at least one of melt infiltration, polymer infiltration and pyrolysis, or chemical vapor infiltration.
11 . The method of claim 1 , wherein at least one of the plurality of composite plies is a ceramic matrix composite ply.
12 . The method of claim 1 , wherein the composite component is a gas turbine engine component.
13 . The method of claim 1 , wherein the composite component is at least one of a turbine rotor blade or a turbine stator vane.