Microstructure and anisotropy of mechanical properties of graphene nanoplate toughened Al2O3-based ceramic composites

Abstract

Graphene nanoplate (GNP)-toughened Al2O3-based ceramic composites were fabricated by the hot-pressing method. The ceramic composites prepared in this way exhibited anisotropy in their mechanical properties. The fracture toughness and flexural strength of the ceramic composites were measured in the vertical to hot-pressing direction (VHPD) and determined to be as high as 6.2 MPa m1/2 and 461 MPa, respectively, with GNP contents of 0.75 vol%, which were improvements of 38% and 39%, respectively, over the values measured in the parallel to hot-pressing direction (PHPD). Scanning electron microscope (SEM) observations indicated that GNPs parallel to each other and perpendicular to the hot-pressing direction are the primary explanation for the mechanical property anisotropy. The energy release rate of the crack deflection was calculated, demonstrating the effect of the GNP orientation on the mechanical properties.