Machinability Study on AA6061/2 SiC / Graphite Hybrid Nanocomposites Fabricated through Ultrasonic Assisted Stir Casting

Aluminium-based hybrid metal matrix nanocomposites (AA-HMNCs) have numerous applications due to their higher strength-to-weight ratio and good mechanical and tribological properties. However, the machinability aspect of these materials must be carefully explored before employing them in various engineering applications. The present study involves the fabrication of AA6061/2 wt.% SiC/x wt.% graphite (x= 1, 2, 3) hybrid nanocomposites and subsequently subjecting them to machinability investigation. All the hybrid nanocomposite samples are fabricated through ultrasonic assisted stir casting technique. The effect of machining parameters and graphite content of the sample on cutting force and surface roughness is discussed based on experimental data. Experiments are performed based on the central composite design of response surface methodology, and the corresponding output responses are recorded. ANOVA analysis revealed that the graphite content has the highest authority over surface roughness and cutting force. High cutting speeds accompanied by low feed and depth of cut have resulted in reduced cutting forces and better surface finish. Chip morphology studies have also subsequently indicated better machinability with increased graphite content.