DIYALA JOURNAL OF ENGINEERING SCIENCES

Abstract

This research is devoted to prepare a functionally graded material (FGM) by using vertical centrifugal casting method and to study the effect of the rotational speed of casting mold on the microstructure and hardness of a hypereutectic (Al-22%Si) alloy. Therefore, the melt was overheated to (850) Cº and poured in the centrifugal casting mold after preheating to (115) Cº. Then casting was carried out at different rotational speed (625, 1027, 1144, and 1907) r.p.m. The results showed, increasing mold rotational speed due to increasing the average volume fraction in the inner layer from cylinder thickness and decreased in the intermediate and outer layer also decreased the grain size of primary silicon. The results of wear tests showed that the maximum wear resistant was found in the inner layer from cylinder thickness at a rotational speed of (1907) r.p.m, and then the outer layer but minimum wear resistant was in the intermediate layer. The results of hardness tests showed that the maximum hardness was found in the inner layer from cylinder thickness, and increased with increasing mold rotation speed and then outer layer and intermediate layer.