A TECHNIQUE FOR MEASURING RESIDUAL-STRESS IN SIC WHISKERS WITHIN AN ALUMINA MATRIX THROUGH RAMAN-SPECTROSCOPY

We measured the Raman spectrum associated with the transverse optical (TO) phonon of cubic SiC (beta-SiC) whiskers as a function of stress using a diamond anvil cell (for hydrostatic stress, X) and an individual whisker microtension apparatus (for uniaxial stress along [111], P). These experiments were used to calibrate the shift and the splitting of the TO phonon mode with applied stress. The results of the calibration experiments were used to evaluate the residual stress in an Al2O3/SiC(w) composite (30% SiC by volume). The Raman spectra from the composite shows that residual stress in the SiC near the surface of the composite is (X + P/3) = -1050 +/- 100 MPa.