Ceramic matrix composites made by chemical vapor infiltration and methods of manufacture thereof

1. A method of fabricating a silicon carbide-containing ceramic matrix composite including a matrix therein, said method comprising:

forming a plurality of holes in a ceramic matrix composite preform of desired shape, wherein the ceramic matrix composite preform has a first face and an opposing second face that define a thickness of the preform, wherein the holes are formed by laser drilling, electrical discharge machining (EDM), water jet machining, or ultrasonic abrasive machining, wherein the ceramic matrix composite preform has a local volume fraction of the plurality of the holes that varies from about 0.1% to about 30% over a surface region of the ceramic matrix composite preform, wherein the matrix is a silicon-containing material selected from the group consisting of silicon carbide, silicon nitride, molybdenum silicide, and mixtures thereof; and

densifying the ceramic matrix composite preform by a chemical vapor infiltration process using silicon to form a part or most of the matrix such that SiC forms within the plurality of holes, wherein the holes of the plurality of the holes vary in cross-sectional dimension through the preform.

2. A method of fabricating a silicon carbide-containing ceramic matrix composite including a matrix therein, said method comprising:

forming a plurality of holes in a ceramic matrix composite preform of desired shape, wherein the ceramic matrix composite preform has a first face and an opposing second face that define a thickness of the preform, wherein the holes are formed by laser drilling, electrical discharge machining (EDM), water jet machining, or ultrasonic abrasive machining, wherein the preform has a porosity of between about 20% to about 80%; and

densifying the preform by a chemical vapor infiltration process using silicon to form a part or most of the matrix such that SiC forms within the plurality of holes.

3. The method according to claim 1 , wherein the preform comprises plies with unidirectional fibers; or plies with a 2-D woven architecture, with or without thru-thickness stitching; or a 3-D fiber architecture made by weaving and/or braiding.

4. The method according to claim 1 , wherein the plurality of holes have a cross-dimensional diameter ranging from about 25 microns to about 250 microns.

5. A method of fabricating a silicon carbide-containing ceramic matrix composite including a matrix therein, said method comprising:

forming a plurality of holes in a ceramic matrix composite preform of desired shape, wherein the ceramic matrix composite preform has a first face and an opposing second face that define a thickness of the preform, wherein the holes are formed by laser drilling, electrical discharge machining (EDM), water jet machining, or ultrasonic abrasive machining, wherein the ceramic matrix composite preform has a volume fraction of the plurality of holes that is between about 0.5% to about 15% for the entire preform, wherein the matrix is a silicon-containing material selected from the group consisting of silicon carbide, silicon nitride, molybdenum silicide, and mixtures thereof; and

densifying the preform by a chemical vapor infiltration process using silicon to form a part or most of the matrix such that SiC forms within the plurality of holes, wherein the holes of the plurality of the holes vary in cross-sectional dimension through the preform.

6. The method according to claim 1 , wherein the holes of the plurality of the holes penetrate the full thickness.

7. The method according to claim 1 , wherein the holes of the plurality of the holes have a cross-sectional shape selected from the group consisting of a circle, square, rectangle, oval, and any other two-dimensional closed pattern.

8. The method according to claim 1 , wherein the holes of the plurality of the holes are tapered.

9. The method according to claim 1 , wherein the ceramic matrix composite is a silicon carbide-silicon carbide composite or a continuous fiber reinforced composite.

10. A ceramic matrix composite formed according to the method of claim 1 .

11. The method according to claim 1 , wherein the local volume fraction of the plurality of holes varies from about 2% to about 10% over a surface region of the preform.

12. The method according to claim 2 , wherein the preform has a porosity of between about 40% to about 70%.

13. The method according to claim 5 , wherein the volume fraction of the plurality of holes is between about 3% to about 10% for the entire preform.

14. The method according to claim 1 , further comprising:

prior to forming the plurality of holes, forming the ceramic matrix composite preform via a uniaxial tape layup or with a cloth layup.

15. The method according to claim 1 , further comprising:

prior to forming the plurality of holes, heating the ceramic matrix composite preform to cause binder burnout therein.

16. A method of fabricating a silicon carbide-containing ceramic matrix composite including a matrix therein, said method comprising:

forming a plurality of holes in a ceramic matrix composite preform of desired shape, wherein the ceramic matrix composite preform has a first face and an opposing second face that define a thickness of the preform, wherein the holes are formed by laser drilling, electrical discharge machining (EDM), water jet machining, or ultrasonic abrasive machining;

coating an inside surface of the plurality of holes with BN; and

thereafter, densifying the preform by a chemical vapor infiltration process using silicon to form a part or most of the matrix such that SiC forms within the plurality of holes.