MEASUREMENT OF CRACK VOLUME DUE TO THERMAL-EXPANSION ANISOTROPY IN ALUMINUM TITANATE CERAMICS

Grain-boundary crack onset and crack volume at room temperature result ing from thermal expansion anisotropy in aluminium titanate ceramics w ere studied by dilatometry. Investigation revealed that specimens with low bulk density have a smaller temperature difference between sinter ing and crack-onset temperature than those of the specimens with high density and the same grain size. The fracture surface energy of alumin ium titanate on the grain-boundary cracking in the present study was a bout 22 J m(-2); the grain-boundary crack volume is proportional to (g rain size)(0.5).