Sacrificial fibers for cooling air flow in ceramic matrix composites, methods of manufacture and articles comprising the same
Disclosed herein is a composite comprising a ceramic matrix composite comprising a ceramic matrix and ceramic fibers; and one or more sacrificial fibers woven into the ceramic matrix composite; where the sacrificial fibers are operative to undergo oxidation or melting upon being subjected to an elevated temperature; and wherein the sacrificial fibers leave cooling holes in the composite preform upon being subjected to oxidation or melting.
1 . A composite comprising:
a ceramic matrix composite comprising a preform including a plurality of woven plies stacked on top of each other in a vertical direction, each woven ply including ceramic fibers in the form of warp fibers extending in a longitudinal direction and fill fibers woven into the warp fibers and extending in a lateral direction; and
one or more sacrificial fibers woven into the preform; where the sacrificial fibers are woven vertically through the plies between warp fibers and fill fibers of each ply and are looped over the sides of the preform; and where portions of the sacrificial fibers are exposed on the sides of the preform; where the sacrificial fibers are operative to undergo oxidation or melting upon being subjected to an elevated temperature; and wherein the sacrificial fibers leave cooling holes in the composite preform upon being subjected to oxidation or melting; wherein the sacrificial fibers comprise glass fibers.
2 . The composite of claim 1 , wherein the ceramic fibers comprise SiC, Al 2 O 3 , BN, B 4 C, Si 3 N 4 , MoSi 2 , SiO 2 , SiOC, SiNC, and/or SiONC.
3 . The composite of claim 1 , wherein the sacrificial fibers have melting points at temperatures of greater than 800° C.
4 . The composite of claim 1 , wherein the sacrificial fiber is present in the ceramic matrix composite in an amount of greater than or equal to 20 wt %, based on a total weight of the ceramic matrix composite.
5 . The composite of claim 1 , wherein the sacrificial fiber is woven into the ceramic matrix composite in a periodic fashion.
6 . The composite of claim 1 , wherein the sacrificial fiber is woven into the preform in an aperiodic fashion.
7 . The composite of claim 1 , wherein the sacrificial fiber has a diameter of 30 to 1600 micrometers.
8 . The composite of claim 1 , wherein the sacrificial fiber further comprises a metal fiber, wherein the metal fiber comprises stainless steel, titanium, tantalum, tungsten, nickel, or a combination thereof.
9 . The composite of claim 1 , wherein the glass fiber comprises E-glass, A-glass, C-glass, D-glass, R-glass, or S-glass.