High temperature mechanical behaviour of liquid phase sintered silicon carbide

Silicon carbide was liquid phase sintered using Y(2)O(3) and AIN as sintering additives. A globular grained microstructure was obtained from alpha-SiC powder whereas a mixture of beta-Sic, with a small amount of alpha-SiC seeds, revealed platelet shaped grains with an aspect ratio of eight. Beside this difference in grain morphology of the alpha-SiC grains, the phase content of the grain boundary phase is different. The influence of both aspects onto the mechanical behaviour, i.e. four-point bending strength between room temperature and 1400 degrees C and fracture toughness between room temperature and 1100 degrees C, are investigated. (C) 1997 Elsevier Science Limited. All rights reserved.