The thermal shock resistance of the ZrB_2-SiC-ZrC ceramic

摘要

In the present work, the thermal shock resistance of the ZrB_2-SiC-ZrC ceramic was estimated by the water quenching method and the flexural strength of the quenched specimen was measured. The measured critical temperature difference of the ZrB_2-SiC-ZrC ceramic was significantly greater than that of the ZrB_2-15 vol.% SiC ceramic. The improvement in thermal shock resistance was attributed to its higher fracture toughness (6.7 MPa m~(1/2) and lower flexural strength (526 MPa) relative to the ZrB_2-15 vol.% SiC ceramic (4.1 MPa m~(1/2) and 795 MPa) based on Griffith fracture criterion. Furthermore, the temperature and thermal stress distributions in the specimen during instantaneous water quenching were simulated by Finite element analysis.