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 Al-0.25%GNPs composite showed better mechanical properties compared with pure Al,Al-0.50%GNPs and Al-0.1.0%GNPs composites.Before extrusion,the Al-0.25%GNPs composite showed ~13.5%improvement in ultimate tensile strength(UTS) and ~50%enhancement in failure strain over monolithic matrix.On the other hand,Al-0.50%GNPs and Al-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.The0.2%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 ~46%with 0.25%graphene nanoplatelets.The superior mechanical properties(in terms of failure strain) of the Al-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 Al 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.