High-temperature tensile strength and fracture behavior of ZrB₂-SiC-graphite composite

The tensile behavior of ZrB₂-SiC-graphite composite was investigated from room temperature to 1800°C. Results showed that tensile strength was 134.18 MPa at room temperature, decreasing to 50.34 MPa at 1800°C. A brittle-ductile transition temperature (1300°C) of ZrB₂-SiC-graphite composite was deduced from experimental results. Furthermore, the effect of temperature on the fracture behavior of ZrB₂-SiC-graphite composite was further discussed by microstructure observations, which showed that tensile strength was controlled by the relaxation of thermal residual stress below 1300°C, and was affected by the plastic flow during 1300°C and 1400°C. At higher temperature, the tensile strength was dominated by the changes of microstructures.