COIVF-9 %Ob 6Y-- N EAR-N ET-SHAPE FABRICATION BY FORCED-FLOW, THERMAL-G RAD1 ENT CVI*

Forced-flow, thermal gradient chemical vapor infiltration (FCVI) has been developed for the rapid densification of ceramic matrix composites. For preforms of >3 mm thickness FCVl can produce a near-net-shape part in less than one day as opposed to isothermal, isobaric CVI which requires several weeks to densify such a component. Efforts at ORNL and elsewhere have resulted in capability to produce prototypical thick-walled heat exchanger tubes and turbine disk blanks. This paper will review recent modeling and experimental efforts related to the FCVl of cylindrical forms