PROPERTIES AND MICROSTRUCTURE OF ALUMINA-NIOBIUM AND ALUMINA-NEODYMIUM TITANATE NANOCOMPOSITES MADE BY NOVEL PROCESSING METHODS

摘要

Alumina-niobium and alumina-neodymium titanate nanocomposites have been fabricated using high-energy ball-milling and Spark Plasma Sintering (SPS). The 10 vol% niobium nanocomposite has a fracture toughness of 7 MPam~(1/2) and a hardness of 22.5 GPa. This is nearly twice as tough as a pressureless sintered composite of the same composition reported in work by Garcia et al [1]. The 9 vol% neodymium titanate nanocomposite increased toughness to 5.7 MPam~(1/2) and was able to retain a hardness value of 19.2 GPa. The increase in toughness in the alumina-niobium can be attributed to ductile-phase toughening, while alumina-neodymium titanate relies on the newly proposed toughening mechanism of piezoelectric-phase strain relief.