Effects of heavy rare-earth addition on glass-forming ability, thermal, magnetic, and mechanical properties of Fe-RE-B-Nb (RE = Dy, Ho, Er or Tm) bulk metallic glass

With the aim of investigating how the species of doped rare-earth (RE) elements affect the glass-forming ability (GFA), 5 at. % RE elements were added in Fe71Nb6B23 alloy to substitute Fe. Compared with the Fe66RE5 Nb6B23 (RE = Ho or Dy), Fe66RE5 Nb6B23 (RE = Er or Tm) possesses an extra competitive Fe3B crystallization phase, which leads to a better GFA by stabilizing the liquid phase structure. Moreover, Fe66RE5 Nb6B23 shows the lowest density of states near the Fermi level among four alloys, which contributes to its best GFA. The influences of RE addition on the thermal, magnetic, and mechanical behaviors were also investigated. With increasing atomic number of RE elements from Dy to Tm, the saturation magnetic flux density increases obviously accompanied by the improved flowability in the supercooled liquid region, which makes Fe66Tm5Nb6B23 as a potential functional soft-magnetic material for thermoplastic machining.