Investigation on microstructural, mechanical and electrochemical properties of aluminum composites reinforced with graphene nanoplatelets

In present study, the microstructure, mechanical and electrochemical properties of aluminum-graphene nanoplatelets (GNPs) composites were investigated before and after extrusion. The contents of graphene nanoplatelets (GNPs) were varied from 0.25 to 1.0 wt.% in aluminum matrix. The composites were fabricated thorough powder metallurgy method, and the experimental results revealed that A1-0.25%GNPs composite showed better mechanical properties compared with pure A1, A1-0.50%GNPs and A1-0.1.0%GNPs composites. Before extrusion, the A1-0.25% GNPs composite showed similar to 13.5% improvement in ultimate tensile strength (UTS) and similar to 50% enhancement in failure strain over monolithic matrix. On the other hand, A1-0.50%GNPs and A1-0.1.0%GNPs composites showed the tensile strength lower than monolithic matrix. No significant change was observed in 0.2% yield strength (YS) of the composites. However, the extruded materials showed different trends. The 0.2%YS of composites increased with increase in GNPs filler weight fractions. Surprisingly, UTS of composites with 0.25 and 0.50% GNPs was lower than monolithic matrix. The failure strain of the baseline matrix was enhanced by similar to 46% with 0.25% graphene nanoplatelets. The superior mechanical properties (in terms of failure strain) of the A1-0.25%GNPs composite maybe attributed to 2-D structure, high surface area and curled nature of graphene. In addition, the corrosion resistance of pure A1 and its composites reinforced with 0.5 and 1.0 wt% GNPs was also investigated. It was found that the corrosion rate increased considerably by the presence of GNPs. (C) 2015 Chinese Materials Research Society. Production and hosting by Elsevier B.V.