Dynamic Compressive Behavior of ZrB2‐Based Ceramic Composites at Room Temperature and 1073 K

Abstract

The dynamic compressive behaviors of ZrB2‐based ceramic composites were investigated through the convenient and high‐temperature Splitting Hopkinson Pressure Bars. The effects of strain rate on dynamic compressive strength, stress–strain relationship and fracture mechanisms were discussed in detail. Moreover, the influence of pre‐oxidation on dynamic strength was also studied at 1073 K. The results indicate that the relationship between dynamic compressive stress and strain for ZrB2‐SiC‐graphite composite is strong nonlinear at room temperature and 1073 K. Dynamic compressive strength increases linearly with the increase of strain rate. The pre‐oxidation effect results in the enhancement of dynamic compressive strength at 1073 K in comparison with the room temperature strength. Based on the microstructures, the dominant intergranular fracture and pull‐out of graphite flake are observed at low strain rates, whereas the transgranular fracture and cutting of graphite flake are found at high strain rates. Fracture mechanisms play a crucial role on the changes of dynamic compressive strength and critical strain with strain rate.