Transformation Toughening by Dispersed ZrO<SUB>2</SUB> in SiC<I><SUB>W</SUB></I>/ZrO<SUB>2</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> Composite

Fracture toughness of SiC whisker and ZrO2 particle reinforced alumina matrix composite was investigated under modeI and modeII loading conditions.Under modeI loading condition, the critical stress intensity factor increased with increasing ZrO2 volume, which well agreed with theoretical estimation. It was also shown by the theoretical analysis that the transformation of ZrO2 was less effective to the toughness of the composite under modeII loading, which was consistent with the experimental results.