Concept Design for Manufacturing of New Advanced C/C Composites for Aerospace Applications

Abstract

Carbon fibers reinforced carbon composites (C/C) are special advanced ceramic materials exhibiting outstanding thermal and mechanical properties as low density, high specific modulus, strength and fracture strain retained also at very elevated temperatures, very high thermal conductivity, low thermal expansion coefficients and consequently excellent thermal shock resistance. They are used in several industrial fields, especially in the aerospace and military sectors, e.g., aircraft disc brakes, sharp re-entry nose tips, thermal protection systems of aerospace vehicles and above all nozzle throat inserts and divergent inner walls of solid rocket boosters. The C/C composites’ thermo-mechanical properties are strongly interrelated with the architecture and orientations of carbon fiber preforms. The present paper, based upon previous activities carried out by the authors in C/C design and manufacturing, introduces a novel technical approach, consisting in an innovative combination of pre-rigidized carbon rods preform with pressure gradient chemical vapour infiltration process, aimed to the fabrication of throat insert components for space propulsion, liquid and solid, rocket engines. In details, the whole manufacturing process is examined, starting from the production of carbon rods of predetermined shape and size through a pultrusion line, to the geometrical design of the main 4D architectures, showing different orientations and packing efficiency up to the investigation of the PGCVI process including experimental testing with 2D preforms and the scanning microscope analysis of the C/C samples densified in this way.