Effect of Yttrium Addition on Glass-Forming Ability and Magnetic Properties of Fe-Co-B-Si-Nb Bulk Metallic Glass

The glass-forming ability (GFA) and the magnetic properties of the [(Fe0.5Co0.5)(0.75)B0.20Si0.05](96)Nb4-xYx bulk metallic glasses (BMGs) have been studied. The partial replacement of Nb by Y improves the thermal stability of the glass against crystallization. The saturation mass magnetization (sigma(s)) exhibits a maximum around 2 at. % Y, and the value of sigma(s) of the alloy with 2 at. % Y is 6.5% larger than that of the Y-free alloy. The coercivity shows a tendency to decrease with increasing Y content. These results indicate that the partial replacement of Nb by Y in the Fe-Co-B-Si-Nb BMGs is useful to simultaneous achievement of high GFA, high sigma(s), and good soft magnetic properties.