Feasibility of Stir Casting Method for Processing Al-6063/Graphite Composite with Desired Microstructure, Mechanical, Flow, and Frictional Properties

The Al-6063/Graphite composite was processed by the stir casting technique. The graphite was copper-coated using a cementation process and introduced into the matrix at 2.5, 5, and 7.5 wt%. The microstructure and the hardness of the composite were examined. The micrographs showed better particle distribution for the graphite reinforcements up to 5 wt%. Further increment resulted in inhomogeneous particle distribution and increase in % void content. The uniaxial compression test was performed to investigate the plastic flow properties. It was observed that an increase in the graphite reinforcement decreased the flow strength. However, the true fracture strain to failure increased. Furthermore, the effect of graphite reinforcement on the friction factor 'm' was analyzed by a ring compression test. The test was performed at various temperatures from 373 to 673 K in the interval of 100 K, including the ambient temperature. It was observed that the graphite reinforcement had a considerable effect on reducing the friction factor during deformation, up to 473 K.