Microprobe fluorescence spectroscopy evaluation of stress fields developed along a propagating crack in an Al2O3 center dot CaO-6Al(2)O(3) ceramic composite

The fracture behavior upon stable crack propagation in bending was investigated for a ceramic matrix composite comprising 15 vol% of calcium hexaluminate (CaAl12O19 or "CA6") in an Al2O3 matrix and compared to the crack bridging stresses as measured by microprobe fluorescence spectroscopy. In addition, piezospectroscopy coefficients of -4.57 and -3.79 cm(-1) GPa(-1) were determined for the peaks located at 14488 and 14528 cm(-1), respectively, for monolithic CA6. It was concluded that the macroscopic R-curve behavior of the composite could be predicted from microscopic bridging stress data and indicated microprobe fluorescence spectroscopy to be a significant experimental tool for the investigation of fracture micromechanisms in ceramic materials.