Investigation on the Mechanical Property and Wear Characteristics of Aluminium-6061 Hybrid Composite Reinforced with Graphene-Nanoplatelets by Stir Casting

Aluminium 6061 composites, known for their application in the automotive, aerospace, and aviation industries, have been reinforced with Graphene Nanoplatelets (GNP) through the conventional stir casting process. The study examines the mechanical and tribological properties of these composites, focusing on variations in GNP weight percentages (2, 3, 5, 10, and 15%). Key findings include decreased density, increased microhardness, improved impact and flexural strengths up to 10 wt.% GNP, and enhanced wear resistance with optimal GNP distribution. Al6061-GNP nano hybrid composites, labeled as samples A, B, C, D, and E, were fabricated using the conventional stir casting method. Theoretical and experimental density measurements of these samples showed a maximum deviation of 0.375%, with densities decreasing from 2.66 to 2.32 g/cm 3 . The presence of graphene nanoplatelets (GNP) reduces the composite density due to their interlocking structure with Al6061. Microhardness testing revealed an increase from 78.8 HV in sample A to 98.7 HV in sample D, showing a 20.16% improvement. This enhancement is attributed to the uniform distribution of GNP within the metal matrix. Impact strength also improved by 53% from sample A to D, highlighting stronger interfacial bonding and better load transfer between Al6061 and GNP. Flexural strength increased by 12.5% from sample A to D, correlating with improved interfacial bonding, which aids in resisting rupture under load. Sample D exhibited the highest flexural strength at 375 MPa, while sample E showed the least deflection. Specific wear rate (SWR) decreased by 22.9% from sample A to D, with coefficients of friction also reducing from 0.348 to 0.281. The presence of a mechanically mixed layer (MML) due to GNP enhances wear resistance and reduces friction. The findings demonstrate that incorporating GNP into Al6061 significantly enhances mechanical properties making these composites promising for advanced engineering applications.