Al-12wt%Si alloy has been manufactured by chill-casting and melt spinning. The resulting microstructures have been examined by optical microscopy. It was found that the microstructure of the ribbons is substantially different from that of the chill casting X-ray diffraction (XRD) patterns were obtained The structure of Al-12wt%Si ribbons for the different disk speeds were examined. In addition, the micro-hardness of the chill casting and the ribbons were measured. It was found that there is a linear relationship between the micro-hardness of ribbons and the disk speeds.