Microstructural study of Al-20Si-5Fe Alloys produced by melt-spinning

Abstract

Al-20si-5Fe ribbons were produced by melt spinning at the rotating speed of 20 and 40m/s. The microstructure of ribbons and conventionally cast alloys were characterized using scanning electron microscopy (SEM) together with the energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) method. The microhardness of the ribbons and as cast ingots was also measured. SEM observations showed that the wheel side of the ribbons exhibited a finer microstructure than those on the air side which exposed to the atmosphere. The phase constitution of the hypereutectic Al-20Si-5Fe alloy was considerably affected by rapid solidification. XRD results showed that the phases present in the as cast hypereutectic Al-20Si-5Fe alloy were identified to be α-Al, Si and intermetallic β-Al5FeSi phases while only α-Al and Si were identified in the melt spun ribbons. Moreover, the values of Vickers microhardness of melt spun ribbons were three times as high as those of conventionally cast ingots of the same alloy.