Mechanical behavior of biomorphic Si/SiC porous composites

Biomorphic Si/SiC porous composites were manufactured by Si melt infiltration of a C template produced by pyrolysis of two types of wood. The mechanical behavior of the composites was studied using compression, bending and fracture tests between ambient temperature and 1350 °C, and the relationship between the mechanical properties and the composite microstructure and density was ascertained. It was found that density (or porosity) was the main factor controlling the strength at ambient temperature, while the presence of residual C determined the high temperature behavior. Composites without residual C maintained the ambient temperature bending and compressive strengths up to 1350 °C, while those which contained residual C after processing showed a dramatic reduction of strength with temperature.