Effect of sintering temperature on densification and mechanical properties of pressureless sintered CNT-alumina nanocomposites

Carbon nanotubes (CNTs) exhibit excellent mechanical, electrical and thermal properties thus have been considered for applications in the production of nanocomposite materials. This work presents results of sintered CNTs-reinforced alumina nanocomposites that can be used for many structural and engineering applications. Gas purging sonication (GPS) was used to achieve homogeneous dispersion of CNTs in alumina powder. Nanocomposites were synthesized by conventional pressureless sintering technique using varying amounts of CNTs in alumina matrix. Densification, hardness and fracture toughness of the resulted nanocomposites were examined. It is found that considerable improvement in fracture toughness at 1 wt% CNT-alumina nanocomposite has occurred. Role of CNTs in improving the fracture toughness of nanocomposites is explained which is attributed to well known bridging and pullout mechanism of CNTs in the matrix.