Influence of stirring speed and stirring time on distribution of particles in cast metal matrix composite

In the present study, high silicon content aluminium alloy-silicon carbide metal matrix composite material, with 10%SiC were successfully synthesized, using different stirring speeds and stirring times. The microstructure of the produced composites was examined by optical microscope and scanning electron microscope. The Brinell hardness test was performed on the composite specimens from base of the cast to top. The results revealed that stirring speed and stirring time influenced the microstructure and the hardness of composite. Microstructure analysis revealed that at lower stirring speed with lower stirring time, the particle clustering was more. Increase in stirring speed and stirring time resulted in better distribution of particles. The hardness test results also revealed that stirring speed and stirring time have their effect on the hardness of the composite. The uniform hardness values were achieved at 600 rpm with 10 min stirring. But beyond certain stir speed the properties degraded again. An attempt is made in this study to establish the trend between processing parameters such as stirring speed and stirring time with microstructure and hardness of composite. (c) 2005 Elsevier B.V. All rights reserved.