Abstract:

Recently we have reported a number of bulk glass forming compositions in the Cu-Hf-Ti system, with the critical thickness for complete glass formation, dc, ranging from 2 mm to 4 mm. In order to improve the glass forming ability (GFA) getting even larger dc, the prevailing approach is to use complex multicomponent systems. This strategy has been investigated by us for the Cu-Hf-Ti bulk glass forming alloy Cu55Hf25Ti20 using >1 at. pct additions of B, Y, Nb, Ta, Al, Mn, Si or V but with no signi?cant improvement in the GFA. Clearly, it is necessary, in order to utilise the full potential of the base ternary system, to identify the best glass-forming compositions as a basis for extending the search into multi-dimensional compositional space. Thus, CuxHfyTiz alloys, where x=(40–70) at. pct, y=(5–30) at. pct, and z=(10–36) at. pct, were prepared by melt spinning and copper mould suction-casting. The composition dependence of the GFA for the Cu-Hf-Ti alloys, as measured by dc for rod and ribbon samples, is reported over the composition range given above.

Key words: Metallic glass formation, Glassy Cu-Hf-Ti alloy, Glass forming ability, Melt spinning, Copper mould suction-casting