EFFECTS OF ELECTROMAGNETIC STIRRING AND WATER COOLING ON STRUCTURE AND SEGREGATION IN CENTRIFUGALLY CAST AL-SI EUTECTIC ALLOY

An investigation is reported into the structure and macrosegregation o f on eutectic Al-Si allow solidified using an electromagnetic centrifu gal casting process. The effects of external magnetic field and water cooling have been experimentally examined. It is found that the as cas t macrostructure is refined both by electromagnetic stirring and by wa ter cooling. As for the microstructures, the electromagnetic stirring causes a change in the silicon morphology from flake to fine dendrite, and produces refined alpha aluminium dendrites and 'divorced' eutecti c. The severity of radial macrosegregation in the air cooled eutectic alloy is reduced by application of a magnetic field, whereas that in t he water cooled alloy is little influenced by a 0.10 T magnetic field.