PROPERTIES AND INTERFACE STRUCTURES OF NI AND NI-TI ALLOY TOUGHENED AL2O3 CERAMIC COMPOSITES

Ni/Al2O3 and Ni-Ti/Al2O3 composites sintered in different atmospheres are investigated Argon as a sintering atmosphere is found to be more b eneficial to the fracture toughness of the composites than CO. Ni incl usions at 12 vol.% enhance the fracture toughness up to 36%, correspon ding to a fracture energy twice that of the alumina matrix, whereas ti tanium alloying to Ni makes a negative contribution to the mechanical behaviour. The interfacial structures of Ni/Al2O3 and Ni-Ti/Al2O3 are studied by using electron microscopy. The titanium distribution at the interfaces is studied and correlated to the mechanical properties.