Effect of GNPs content at various compaction pressures and sintering temperatures on the mechanical and electrical properties of hybrid Cu/Al2O3/xGNPs nanocomposites synthesized by high energy ball milling

Hybrid nanocomposites can be synthesized by high energy ball milling to form different compositions of Copper (Cu) strengthened with 10% alumina (Al2O3) and x graphene nanoplatelets (GNP) Cu-10%Cu/Al2O3/xGNPs (x = 0, 0.25, 0.5, 0.75, 1 wt%). Each mixture has been uniaxially compacted at pressures from 300 to 1200 MPa and sintered at three temperatures: 900, 950 and 1000 degrees C for 2hr. The effect of changing both compaction pressure and sintering temperature values for each mass fraction of the GNPs is investigated on the microstructural, mechanical characteristics, and electrical resistivity of the Cu-10%Al2O3/xGNPs hybrid nanocomposites. The results elucidate that the optimum mechanical and physical properties for producing the Cu-10%Al2O3/xGNPs nanocomposites are at compaction pressure of 700 MPa and sintering for 2 h at temperature of 1000 degrees C. Moreover, the addition of 0.5% of GNPs (Cu-10%Al2O3/xGNPs) enhances the mechanical properties of the nanocomposites by 68% due to high mechanical properties and the reduction in the particle size of the graphene nanoplatelets. Whereas, increasing GNPs content more than 0.5%, leads to the reduction of the mechanical and physical properties of these composites due to the agglomerations of GNPs on the limits of the grain of Cu and Al2O3.