Soft magnetic properties and glass formability of Y-Fe-B-M bulk metals (MÂ =Â Al, Hf, Nb, Ta, and Ti)

The glass formability, magnetic properties and thermal stability of the Y-Fe-B-M bulk metals (M = Al, Hf, Nb, Ta, and Ti) alloys have been investigated. For (Y0.06Fe0.72B0.22)98M2 series alloys, Al or Hf addition deteriorates the glass forming ability (GFA), but Nb or Ta addition broadens supercooled region from 50.2 °C for ternary rod to 61.5 °C for M = Ta and 62 °C for M = Nb, respectively. The bulk glassy rod as large as 3 mm in diameter can be obtained. However, their magnetization and Curie temperature are reduced due to the magnetic dilution by the addition of these nonmagnetic elements. On the other hand, for Y4Fe72B22M2 series alloys, almost all the substitution elements, except Al, can improve GFA of alloy rod, making the diameter of bulk glassy rod as large as 3 mm for Ti or Hf substitution and 4 mm for Ta or Nb substitution, respectively. It is arisen from the further expansion of the supercooled region to 70.4-84.2 °C. In this study, Y4Fe72B22Ta2 amorphous rod displays the optimal glass forming ability and also good soft magnetic properties of σs = 123 emu/g, Hc = 0.2 Oe, and TC = 276 °C.