Microstructures and High-Temperature Hardness of Al₂O₃/SiC Nanocomposites

Abstract

The purpose of this paper is to investigate in detail the relation between the microstructure and high-temperature hardness for Al₂O₃/SiC micro-and nanocomposites. Two types of Al₂O₃/SiC composites were fabricated by hot-pressing the mixtures obtained by a conventional ceramic process. Al₂O₃/finer-SiC composites showed a peculiar microstructure with nanometer-size SiC particles located inside the matrix Al₂O₃ grains, yielding “nanocomposite”, whereas Al₂O₃/2μm-SiC composites had the 2μm-SiC particles dispersed at the grain boundary, yielding “microcomposite”. The addition of SiC was found to be very effective in improving the high-temperature mechanical properties of Al₂O₃ for both of the above Al₂O₃/SiC composites. Especially, Al₂O₃/finer-SiC nanocomposites exhibited a better deformation resistance and anti-creep behavior at high-temperatures.