ELASTIC-MODULUS OF CERAMICS AT ELEVATED-TEMPERATURE .3. COMPARISON OF VARIOUS EXPERIMENTAL METHODS

A test technique for measuring elastic modulus at elevated temperatures was developed by using impact sound. The elastic moduli of SiC, Si3N4 and SiAlON decreased slightly with increasing temperature, The elastic modulus of Al2O3 decreased by about 12% with an increase in temperature by similar to 1000 degrees C. The Poisson's ratio did not depend upon the temperature. Prismatic beam specimens were more effective than rod beam specimens for measuring the natural frequency of torsional vibration by using this method, because the natural frequency of torsional vibration was measured and then the Young's modulus, the shear modulus and the Poisson's ratio could be calculated therefrom.