Fracture Behavior of SiC Whisker-Reinforced Al_2O_3 with Modified Interfaces

Carbon-coated SiC whiskers have been examined as a function of coating thickness for reinforcement in Al_2O_3. A compliant carbon layer at the whisker/ matrix interface modifies the residual stress due to thermal expansion mismatch and changes the interfacial chemistry. The fracture behavior of this material has been observed using 4-point bending for strength and the double cantilever beam technique for fracture toughness and R-curve behavior. The strength and R-curve behavior of composites with and without whisker coatings of carbon are presented to evaluate the effect of modified interfaces on the mechanical performance of whisker composites.