Fractoluminescence of the Zirconia Ceramics with Different Porosity under Dynamic Loading

An extensive experimental investigation on zirconia ceramic specimens with different porosity was carried out to evaluate the influence of porosity on fractoluminescence pulse distribution and energy dissipation. Experiments were carried out using Split Hopkinson Pressure Bar (SPHB) setup with strain rate from 400 to 3000s-1. Porosity of the specimens was varied from 10% to 60% volume fraction. Energy dissipation was calculated from the SPHB data. Fractoluminescence was detected by a fast Photo Multiplier Tubes (PMT). Analysis of the fragment size distribution shows that it can be approximated by power law where power (slope in log-log coordinates) depends on the porosity. Fractoluminescence consists of pulses with sharp front and exponential decay with different amplitudes. Pulses were recorded even 1ms after the loading pulse, which is order of magnitude higher than load pulse duration. Intervals between subsequent pulses (or the rate of the pulses as in the Omori law) was measured. It was found, that interval complementary cumulative distribution is bimodal power law distribution. Knee position depends on the porosity of the specimen