Development of graphene nanoplatelets reinforced aluminium matrix nanocomposites by a combination of semi-solid stirring and ultrasonic treatment

Abstract

Graphene Nanoplatelets (GNPs) consisting of graphene layers with a thickness less than 100 nm have recently emerged as a promising reinforcement type owing to their excellent physical and mechanical properties to improve mechanical properties of alloys beyond ceramic nanoparticles. Although there are numerous studies on GNPs reinforced polymer matrix composites in the literature, the number of studies related to the incorporation of GNPs in metal matrices is limited. It is a challenging task to incorporate and uniformly distribute GNPs into liquid metals due to their poor wettability and large surface-to-volume ratio. The purpose of this study is to effectively disperse GNPs into liquid aluminium. 0.5 wt.% GNPs with an average thickness of 50-100 nm and size of 5 ?m were first incorporated into A360 aluminium alloy under semi-solid stirring, and then the composite was ultrasonically treated in fully liquid state. The microstructural investigation of the nanocomposites by optical and scanning electron microscopy may suggest that relatively uniform distribution and effective deagglomeration of GNPs in the matrix were achieved. The hardness of the GNPs reinforced nanocomposites increased in comparison with that of semi-solid stirred and ultrasonically processed A360 alloy without reinforcement, indicating the potential of GNPs for strengthening metals. © 2016, European Conference on Composite Materials, ECCM. All rights reserved.