Preparation and Mechanical Properties of Graphene Nanosheet Reinforced Alumina Composites

Dense graphene nanosheets (GNSs)/Al2O3 composites have been prepared by spark plasma sintering from ball milled expanded graphite and Al2O3 powder. GNSs have been found to be homogeneously distributed in the alumina matrix. Results show that the introduction of GNSs leads to obvious refinement of Al2O3 grains and improvement of mechanical properties of the as-prepared composites. Compared with monolithic Al2O3, the flexural strength, fracture toughness, and Vickers hardness of as-prepared GNSs/Al2O3 samples have been improved by 103, 25, and 26%, respectively, which are attributed to the grain refinement, strong interfacial bonding, and pull-out of GNSs from the matrix.