Mechanical properties of boron carbide plus graphene platelet composites

Boron carbide (B4C) based composites, containing 4-10 wt% of graphene platelets (GPLs) as sintering additive (approximately 4 wt%) and reinforcing phase were prepared by hot-pressing (HP) at 2100 degrees C for 1 h. The effect of GPLs content on microstructure and mechanical properties has been investigated. All investigated mechanical properties were the highest in the case of B4C+4.5 wt% composite with bending strength of 398 MPa and fracture toughness of 5.89 MPa m(1/2). Higher GPLs content resulted in lower mechanical properties except fracture toughness. Processing flaws in the form of GPLs agglomerates and structural inhomogeneities were identified as fracture origins. The main toughening mechanisms, responsible for the increased fracture toughness are crack deflection, crack branching and crack bridging. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.