Effect of reinforcement amount on the microstructural and mechanical properties of mechanically alloyed graphene nanoplatelet reinforced Al-3.5 wt% Cu composites

In this study, various amounts (0.25, 0.5, 0.75, 1, and 2 wt%.) of graphene nanoplatelets (GNPs) reinforced Al-3.5 wt% Cu metal matrix composites were produced using powder metallurgy processes consisted mechanical alloying and pressureless sintering. To compare the properties of the sintered composites, as-blended and 4 h mechanically alloyed powders were sintered to yield Al-3.5 wt% Cu matrix alloys. The microstructural, thermal and mechanical properties were examined using relevant characterization techniques. The formation of Al2Cu phase was detected at all XRD patterns of the sintered samples other than matrix and reinforcement phases. Mechanically alloyed powders exhibit the equiaxed particle morphology compared to the as-blended ones, their mechanical properties were found better than as-blended and sintered samples. Additionally, mechanical alloying led to the dispersion of GNP reinforcements into the AlCu matrix. The highest hardness value (around 153 HV) was obtained for 2 wt% GNP reinforced composite. The highest wear resistance was recorded for 1 wt% GNP reinforced composite with 2.07 +/- 0.2 mm(3)/N.mx10(-3) wear rate. Additionally, composites' compressive strength improved with adding 1 wt% GNP (similar to 68.5 MPa). The good dispersion of the optimum amount of GNP's via mechanical alloying provide to obtain preferable mechanical properties.