Development of C/PyC/SiC CMCs by CVI Process for Hypersonic Vehicle Application

Abstract

Hot structures are essentially required for the hypersonic vehicle applications owing to their operation in the dense flight environments. This paper aims at the development and testing of ceramic matrix composite components for air breathing hypersonic vehicle application. In this regard, 2.5D C/PyC/SiC composites were prepared by isothermal Chemical vapour infiltration (CVI) process. X-ray CT analysis was employed to understand the extent of CVI densification in the ceramic matrix composites laminates, and it was under stood that that the intra-bundle infiltration precedes the inter-bundle infiltration with an edge (high) to center (low) gradient. The composite specimens showed an average tensile strength of 206 ± 21 MPa and an average flexural strength of 405 ± 25 MPa, respectively, at room temperature. Thermal conductivity of composite specimens shows an increase in trend with temperature. The composite laminates were successfully tested for use in the air intake ramps of hypersonic air breathing engines.