Glass-forming ability of RE–Al–TM alloys (RE=Sm, Y; TM=Fe, Co, Cu) Original Research Article

The glass-forming ability (GFA) of RE–Al–TM (RE=Sm, Y; TM=Fe, Co, Cu) upon melt-spinning and die-casting into a copper mold has been studied. Melt-spun ribbons for both Sm- and Y-based alloys show a fully amorphous structure. However, die-casting revealed that Sm-based alloys exhibit a higher GFA than Y-based alloys. The as-cast Sm70Fe20Al10, Sm60Fe20Al10Co10 and Sm60Fe20Al10Co5Cu5 cylinders (3 mm×50 mm) contain a mixture of amorphous and crystalline phases after copper-mold casting. A new bulk metallic glass was obtained for the Sm60Fe10Al10Co15Cu5 alloy, which shows ferromagnetic behavior. In contrast, as-cast Y-based alloys are completely crystalline. Based on the data of the activation energy for crystallization of the amorphous phase, Ex, and the crystallization temperature, Tx, together with magnetic measurements, it is concluded that the as-cast Sm60Fe10Al10Co15Cu5 cylinder displays a tendency for clustering. The improved glass-forming ability of Sm-based alloys is interpreted in terms of classical nucleation theory.