Failure Mechanisms During Thermal Shock Testing of Advanced Ceramics by Means of Lamp Irradiation

Abstract

Thermal shock behaviour of tape-cast Y-PSZ substrate is characterized by lamp irradiation, i.e. the generation of strong lateral temperature gradients in thin circular discs by rapid heating with a high power halogen lamp while in situ measuring the temperature fields with a high speed thermal imaging system. Special attention is paid on failure mechanisms of the samples. Numerical simulation of the specimens deformation indicates buckling of the discs due to radial compression stresses. This causes significant bending components superposing the in-plane thermal stress. Hence, depending on the geometry of the samples marked mistakes in the characterization of the thermal shock behaviour are made if buckling is not considered. In situ off-plane deformation measurements with a Laser-Doppler-Interferometer confirm the theory and verify the Finite-Element simulation. An approach is proposed how buckling has to be taken into account both, in the field of experiment and simulation.