Glass formability and fragility of Fe 61Co 9− xZr 8Mo 5W xB 17 ( x = 0 and 2) bulk metallic glassy alloys

Abstract

The glass-forming ability (GFA) of Fe 61Co 9− x Zr 8Mo 5W x B 17 ( x = 0 and 2) alloys was investigated in terms of the temperature interval of the melting process Δ T m, the reduced glass transition temperature T rg, the modified GFA parameter γ m, as well as the packing density ρ meas/ ρ cal. The GFA parameters indicate that tungsten increases the glass formability of the alloys. The fragility of the alloys was discussed according to the Vogel–Fulcher–Tamman (VFT) equation, showing the fragility indexes of 47 and 39 for tungsten contents of 0 and 2 at.%, respectively. The role of the tungsten in the alloys has been discussed from the minor addition technological point of view.