Microstructure and mechanical behaviors of 2D-Cf/ZrB2-SiC composites at elevated temperatures

Microstructure and mechanical behaviors of the 2D-C-f/ZrB2-SiC composites at RT to 1800 degrees C were studied. It is indicated that the interface structure is critical, which affects the matrix phase composition and cracks deflection path in the intra-bundle area. It subsequently determines the load transmitting, cracks propagation behaviors and the mechanical properties of the composites. Flexural strength of the composites increases slightly at 1000 degrees C by the release of residual stress and self-healing of defects. Partial decomposition and crystallization of polycarbosilane (PCS) derived SiC result in the weakening of the SiC matrix at 1500 degrees C. On the other hand, residual carbon reacts with ZrO2 impurity above 1300 degrees C. As a result, the matrix turns to porous structure at 1500 degrees C, leading to the formation of short micro cracks. At higher temperature of 1800 degrees C, quasi-creep mechanical behavior is presented in the composite.

Automated summary

Microstructure and mechanical behaviors of 2D-C-f/ZrB2-SiC composites were examined, showing the critical role of interface structure in determining mechanical properties. The composites displayed varied mechanical behaviors at different temperatures.