Structural and magnetic phase transitions in Fe-Zr-B-Al(-Cu) amorphous and nanocrystalline alloys

Thermo-magnetic studies combined with transmission electron microscopy of Fe87.5Zr6B5.5Al1 and Fe85Zr6B7.5Cu1Al0.5 amorphous and nanocrystalline alloys revealed the precipitation of a single BCC alpha-Fe nanocrystalline phase during the first stage of crystallization and the formation of intermetallic phases, the growth of alpha-Fe nanograins and further precipitation of alpha-Fe nanograins from the residual amorphous phase during the second stage of crystallization. The presence of 1 at% Cu in the second alloy accelerates the precipitation of the single nanocrystalline phase during the first stage of crystallization and facilitates further precipitation of alpha-Fe nanograins from the residual amorphous phase during the second stage of crystallization.