Rapid heating thermal shock study of ultra high temperature ceramics using an in situ testing method

In this paper, the rapid cooling thermal shock behaviors of ZrB₂–SiC ceramics were measured using traditional water quenching method, and the rapid heating thermal shock behaviors of ZrB₂–SiC ceramics were investigated using a novel in situ testing method. The measured critical thermal shock temperature difference for rapid cooling thermal shock was 373.6 °C; however, the critical thermal shock temperature difference for rapid heating thermal shock of ZrB₂–SiC ceramics was measured to be as high as 1497.2 °C. The thermal stress distribution states after rapid cooling thermal shock and rapid heating thermal shock testing were analyzed using finite element analysis (FEA) method. The FEA results showed that there is a tensile stress existed on the surface for rapid cooling thermal shock, whereas there is a compressive stress existed on the surface for rapid heating thermal shock. The difference of thermal stress distribution resulted in the difference of the critical temperature difference for rapid cooling thermal shock and rapid heating thermal shock.