An investigation on the effect of rotational speed on microstructure of A390 hypereutectic alloy

Functionally graded aluminum matrix composites to the advantage of lightness as same as high hardness and good wear resistance can have many applications in the aerospace and automotive industry, which with more investigations can be reached to the optimum condition by centrifugal cast method. A390 hypereutectic alloy was cast cylindrically as the base alloy with rotational speed of , 1200, 1400, 1600 & 2000rpm by vertical centrifugal cast method. The Microstructures of samples were investigated by optical microscope. Also the volume fraction of reinforcement particles and their hardness from inner wall through outer wall were investigated. It was found because of smaller density of primary Si particles than molten Al, These particles were moved to the inner wall of the samples due to centrifugal force and were distributed from inner layer through middle layer as gradient. The rotational speed of 1400 rpm was chosen as optimum speed and therefore the centrifugal sample with rotational speed of 1400 rpm was chosen as optimum sample.