In situ hot‐pressed ZrB2‐based composite with polycarbosilane‐derived SiC: Microstructure and mechanical behavior

Abstract

AbstractIn this study, a homogenously dispersed finer SiC particles‐containing ZrB2 composite was prepared using nanosized polycarbosilane (PCS) particles‐containing ZrB2 mixture powder, followed by hot pressing. The microstructure of the resulting composite was characterized by field‐emission scanning electron microscopy and transmission electron microscopy. The composite microstructure comprised finer equiaxed ZrB2 and SiC grains. The mechanical behavior of the composite was evaluated using four‐point bending test at different temperatures between room temperature (RT) and 1600°C. The results show that the composite exhibited only linear deformation behavior prior fracture at or below 1500°C. However, a trace quantity of nonlinear deformation was observed at 1600°C. In addition, the flexural strength of the composite decreased as the temperature increased from RT to 1200°C, then the strength increased as the temperature raised to 1400°C. Subsequently, the flexural strength remained almost the constant between 1400°C and 1600°C, with a strength of ~760 MPa.