Microstructure and Mechanical Properties of SiC Whisker-reinforced ZrB_2 Ultra-high Temperature Ceramic

摘要

SiC whisker-reinforced ZrB_2 matrix ultra-high temperature ceramic were prepared at 2000℃ for 1 h under 30MPa by hot pressing and the effects of whisker on flexural strength and fracture toughness of the composites was examined. The flexural strength and fracture toughness are 510 ± 25MPa and 4.05 ± 0.20MPa·m~(1/2) at room temperature, respectively. Comparing with the SiC particles-reinforced ZrB_2 ceramic, no significant increase in both strength and toughness was observed. The microstructure of the composite showed that the SiC whisker was destroyed because the SiC whisker degraded due to rapid atom diffusivity at high temperature. The results suggested that some related parameters such as the lower hot-pressing temperature, a short sintering time should be controlled in order to obtain SiC whisker-reinforced ZrB_2 composite with high properties.