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

Abstract 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 Sm 70 Fe 20 Al 10 , Sm 60 Fe 20 Al 10 Co 10 and Sm 60 Fe 20 Al 10 Co 5 Cu 5 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 Sm 60 Fe 10 Al 10 Co 15 Cu 5 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, E x , and the crystallization temperature, T x , together with magnetic measurements, it is concluded that the as-cast Sm 60 Fe 10 Al 10 Co 15 Cu 5 cylinder displays a tendency for clustering. The improved glass-forming ability of Sm-based alloys is interpreted in terms of classical nucleation theory.