Measurement of Elastic Constants of Ceramics by a Scanning Laser Acoustic Microscope

Abstract

A scanning laser acoustic microscope, SLAM, is applied to measure velocities of sound and to evaluate elastic constants of ceramics. The method of measuring sound velocity is based on spectral interferometry utilizing the interference fringes for a sample and for a reference material. In this study, a suitable sample holder is made to excite the ultrasonic waves to the desired mode, i.e., the longitudinal or the transverse mode, within the sample. Young's modulus, shear modulus, and Poisson's ratio of partially stabilized zirconia ceramics are evaluated from the measured velocities of sound. Then tensile tests are performed on the same sample and the elastic constants are measured. The elastic constants evaluated by SLAM are in agreement with those obtained by the tensile tests within a deviation of about l0 %. The method described here is useful for small specimens of the ceramic materials.