Paper Title
Grain Refinement of Cast Al-Si-Mg Alloys using Electromagnetic Stirring

This paper describes the effect of electromagnetic stirring current (11-15A) on the microstructure of Al-7%Si- 0.5%Mg and Al-17%Si-0.5%Mg alloys. Electromagnetic stirring (EMS) of semi-solid aluminium alloys was carried out under continuous cooling conditions. To investigate the effectiveness of the EMS systems, castings processed by EMS using different current values and mechanical stirring were prepared using graphite mould (to ensure slow cooling rate). It was found that EMS can be effectively used with hypoeutectic and hypoeutectic Al-Si alloys to get modified eutectic even without any modifier. EMS was found to be more effective than mechanical stirring in controlling the microstructure of as cast samples. The optimum current for EMS to achieve the better control over the structure varies with silicon content in the alloy. Optimum current was found to increase with increase in Si content in aluminium alloy. At very low currents the Electromagnetic stirring gave better results as compared to that at high current and mechanical stirring. Results were substantiated by scanning electron microscopy. Keywords - Cast Al-Si-Mg alloy, electromagnetic stirring, mechanical stirring, current, eutectic modifications and grain refinement