Low density biomorphic silicon carbide: microstructure and mechanical properties

Low density biomorphic SiC ceramics have been fabricated by melt infiltration of pine carbon templates. The resulting porous microstructure is anisotropic and presents a high level of connectivity. Some templates have been partially infiltrated to document the details of the infiltration process. The material has been tested at a constant compression with a strain rate of 2×10−5 s−1 at high temperatures between 1150 and 1350 °C. The materials showed high compressive strengths relative to the density, with values up to 241 MPa in the axial direction. The compressive strengths relative to those of fully dense SiC are a good extrapolation of previous studies with denser samples, and present qualitative agreement with the model by Gibson and Ashby for plastic collapse of cellular solids.