MORPHOLOGY OF MAGNESIUM LITHIUM ALUMINUM SILICATE MATRIX REINFORCED BY SILICON-CARBIDE FIBERS DURING HIGH-TEMPERATURE TESTS

For ceramic matrix composites based on SiC fibers in a magnesium lithium aluminum silicate matrix, the vitro-ceramic matrix has been found two-phased, made of cordierite and spodumene. This morphology evolves during heat treatment and/or creep tests. The morphological characteristics - volume fraction, specific perimeter, specific surface area and mean chord length in number and in weight - of the cordierite phase in this matrix have been investigated and quantified, using automatic image analysis and more specially the P(l) function and granulometry in grey tone levels. Evidence is given on a demixtion in the cordierite phase followed by a coarsening at temperatures above 1300K.