Investigations on mechanical and machinability behavior of aluminum/flyash cenosphere/Gr hybrid composites processed through compocasting

This work focuses on characterization of a novel hybrid Aluminum Metal Matrix Composite (AMMC) developed through two-step compocasting method by reinforcing constant amount of flyash cenosphere (10%) and varying quantity of graphite (2%, 4% and 6%). Morphological analysis result shows the presence of dendritic arms and homogeneous distribution of the cenosphere and graphite in Al7075 matrix. The hardness and tensile strength upturn with addition of cenosphere and vice versa for the addition of graphite. The reinforcement particles have enhanced the tensile strength of Aluminum matrix from 178 N/mm2 to 213 N/mm2 as of the composite is concerned. Addition of cenosphere improves the wear resistance considerably and wear rate decreases further with graphite addition due to its self-lubricating nature. Machinability (turning) characteristics of the developed hybrid composite were studied in detail besides optimizing the machining parameters employing Artificial Neural Network (ANN) technique. Based on the ANOVA results it was found that cutting speed and % of graphite addition have the major contribution in minimizing the surface roughness of developed composite.