Research on thermal shock resistance of ZrB₂-SiC-AlN ceramics using an indentation-quench method

The indentation-quench method has been used to evaluate the thermal shock behavior of hot-pressed ZrB₂-20 vol.%SiC-10 vol.%AlN ceramics through both experiments and modeling. The samples with indented cracks are thermal shocked in a series of temperature differences (ΔTs) into water bath of 20 °C. The percentage crack growth is calculated from the individual cracks along the surface to evaluate the thermal shock resistance of this material. The mechanical and thermal properties controlling the stress intensity response of residual stress and thermal stress have been determined as well as R-curve behavior has been studied by indentation-bending method. The curves of percentage crack growth versus ΔTs show that crack propagates stably with increasing ΔTs from 100 to 400 °C, at low ΔTs (ΔT < 100 °C) no significant crack growth is detected, otherwise when ΔTs are greater than 400 °C the crack extends unstably. Whereafter, a theoretical model considering both residual stress and thermal stress is established to analyze this process which is in good agreement with the results of experiments.