Acoustic Emission during Indentation into MgAl2O4 Ceramics

Time series of acoustic emission pulses are recorded when the surface of MgAl2O4 ceramics is damaged by the introduction of a Vickers pyramid. Based on the data of the frequency analysis of the emitted sound, the ratio of the size of intra- and intergranular microcracks is estimated depending on the load on the indenter. The statistical analysis shows that the energy distribution in acoustic pulses is always random, typical of the uncorrelated development of a fracture.