Graphene tweaking Hamaker constant of SiC nanoparticles: A new horizon to solve the conflict between strengthening and toughening

This study reveals a promising feature of graphene encapsulating process to significantly enhance the mutually inclusive tensile strength and ductility of aluminium based composites using the semi-solid powder forming process. It was corroborated based on van der Waals-Casimir interaction free energy that graphene sheets have an unprecedented capacity to manipulate the Hamaker constant of SiC nanoparticles, prompting formation of nano/micro-sized grains. Authenticating by the strengthening model, fractographic observations have also demonstrated the unique functionality of graphene sheets in strengthening via grain refining, thermally enhanced dislocations, shear-lag, geometrically necessary dislocations, crack bridging and fibre pull out mechanisms. (C) 2016 Elsevier Ltd. All rights reserved.