Abstract
Aluminum alloys (AA) are interesting for their low weight and good mechanical properties. The addition of graphene nanoplatelets (GNPs) can be used to reduce the density and to modify the functional properties and mechanical performance of the metal matrix. Graphene reinforced AA matrix composites (AA-GNPs) were prepared by spark plasma sintering technique (SPS), using commercial graphene nanoplatelets mixed with recycled milled AA chips. Monolithic AA and aluminum composites with 2.5 wt.% of GNPs (AA-2.5GNPs) were compacted into disc-shaped samples. The microstructure was studied and characterized with optical (OM) and scanning electron (SEM) microscopies. Hardness was measured and tribological properties were studied by ball-on-disk technique. Coefficient of friction and wear rates were evaluated. Worn surfaces were studied by SEM and confocal microscopy, and level of oxidation was measured using EDX spectrometry. The developed process presented here provides promising results for preparing AA-2.5GNPs nanocomposites from low-cost recycled AA chips with SPS.

Key words
aluminum alloy, aluminum matrix composites, graphene nanoplatelets, spark plasma sintering, wear

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