The temperature-dependent fracture strength model for ultra-high temperature ceramics

Breaking down the entire structure of a material implies severing all the bonds between its atoms either by applying work or by heat transfer. Because bond-breaking is indifferent to either means, there is a kind of equivalence between heat energy and strain energy. Based on this equivalence, we assume the existence of a constant maximum storage of energy that includes both the strain energy and the corresponding equivalent heat energy. A temperature-dependent fracture strength model is then developed for ultra-high temperature ceramics (UHTCs). Model predictions for UHTCs, HfB(2), TiC and ZrB(2), are presented and compared with the experimental results. These predictions are found to be largely consistent with experimental results.