The mechanical behaviour of two 3Al(2)O(3) . 2SiO(2) dense mullite mat
erials with the same level of impurities but different in nature has b
een studied. Microstructure has been characterized by SEM and TEM. rou
ghness, bend strength and Young's modulus have been determined from ro
om temperature up to 1400 degrees C. Dependence of toughness on strain
rate has been investigated. Special attention has been paid to correl
ate the trend of the mechanical parameters to fractographic observatio
ns by SEM.