Abstract
This paper investigates the interfacial bonding, interfacial nanostructure and reinforcing ability of 4 vol% multi-walled carbon nanotubes (mwCNT) and 6 vol% silicon carbide nanoparticles (SiCNP) in inductively sintered alumina ceramic hybrid nanocomposites. Homogenously dispersed reinforcing inclusions led hybrid nanocomposites to three-fold finer microstructure and respective 81% and 25% higher fracture toughness and microhardness over the monolithic alumina. Better mechanical properties were correlated with distinctive toughening mechanisms of crack-deflection as well as crack-bridging induced by reinforcing phases upon establishing sturdy interfaces with the alumina matrix. Moreover, the bonding mechanisms and nanostructural development at the mwCNT/alumina and SiCNP/alumina interfacial regions were probed by means of both qualitative and quantitative approaches. The results show strong interfacial bonding of alumina with mwCNT and SiCNP through an intermediate interfacial layer in the former case and direct physical sticking in the latter one. The bonding chemistry and nanostructural features at the interfaces are meticulously discussed. We also discuss the high temperature stability of the hybrid nanocomposites under air and argon atmospheres. (C) 2019 Elsevier B.V. All rights reserved.