Preparation and Mechanical Properties of Graphene Nanosheet Reinforced Alumina Composites

Dense graphene nanosheets (GNSs)/Al 2 O 3 composites have been prepared by spark plasma sintering from ball milled expanded graphite and Al 2 O 3 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 Al 2 O 3 grains and improvement of mechanical properties of the as‐prepared composites. Compared with monolithic Al 2 O 3 , the flexural strength, fracture toughness, and Vickers hardness of as‐prepared GNSs/Al 2 O 3 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.