SELECTIVE MATERIAL CHARACTERISATION OF CERAMIC MATRIX COMPOSITES FOR ADVANCED GAS TURBINES

摘要

A selective modular service representative methodology as part of a full characterisation strategy for CMC materials for advanced gas turbines is presented on the example of a C/C-SiC and a SiC/SiC material. The first module presented here showed its versatility to rank arbitrary materials by their performance before passing to a costly full material characterisation in order to derive the relevant design data for engineering purposes. No major problems were encountered in mechanical and thermophysical properties measurement, in material analysis and in thermal shock testing. The interpretation of the results from mechanical testing in order to derive an applicable design strength remains however an unresolved issue for the time being. Major problems have been encountered in service representative environmental testing as the most critical material selection test. Accelerated material damage due to the diffusion of chemical agents along the fibre plane has to be avoided either by adequate protection means of the cutting edges, different sample shapes and/or modified test facilities and procedures.