CMC Evaluation for Use in Military Aircraft Engines

Abstract

Because of their relatively low density, high toughness and refractoriness, Ceramic Matrix Composites are of great interest for use in turbine engines. For now several years, SNECMA have been conducting a series of cross-investigations, in cooperation with SEP , on C/SiC and SiC/SiC, both on parts behaviour and materials evaluation.

Several types of static or semi-static hot parts have been fabricated and tested both on ground and flying benches. These tests have been cumulating several hundred of hours exploring the whole field of loading of the parts.

In parallel, several series of tests have been performed to assess the mechanical behaviour of the parts. A particular attention has been put on the misalignment of the fibres which characterizes the structure in the areas of complex shape.

Oxidation tests have been carried out on uncoated materials. Oxidation kinetics have been established and microstructural examinations have been done in a way to precise the location of the initial damaged areas and the phase transformations.

Alternative wear tests have been conducted in conditions simulating the contacts between the parts themselves and the metallic actuators.