EFFECT OF SIC SUBMICROMETER PARTICLE-SIZE AND CONTENT ON FRACTURE-TOUGHNESS OF ALUMINA-SIC NANOCOMPOSITES

A simple model was developed which describes the effect of SIC submicr ometer particles on the fracture toughness of alumina-SiC ''nanocompos ites.'' This effect was attributed to the change in the fracture mode observed in alumina on adding SiC submicrometer particles, which was s uggested to be a result of both matrix weakening and grain boundary st rengthening. The model suggests that the increase in fracture toughnes s should be obtained only for small additions (less than 5 wt%) of SiC .