Abstract
Mechanical properties of $Al_2O_3$ based composite ceramics reinforced by SiC whiskers up to 40% by volume we-re investigated. Specimens were hot pressed at $1, 500^{\circ}C$ under 28.5MPa for 30min in Ar atmosphere. Porosities room temperaturefracture toughnesses and flexural strengths up $1, 000^{\circ}C$ were measured. Porosities were increa-sed as the SiC whisker cortent increased. After compensating the effect of porosities that means extrapolated in zero porosities the reinforced composites exhibited increases in flexural strength and fracture toughness as the whi-sker content increased, .