Amorphous alloys in the Cu-Hf-Ti system

Abstract

Good bulk glass forming alloys can be found over a wide range of compositions in the neighborhood Of CU60Hf25Ti15. The glass forming ability, thermal and mechanical properties of the Cu-Hf-Ti system is examined for alloys in the composition range of 57.5 < Cu < 62.5, 22.5 < Hf < 28.75, 11.25 < Ti < 17.5 (at.%). These alloys typically have strength similar to 2 GPa, Hv >= 600, T-g similar to 450 degrees C, and Delta T similar to 50 degrees C, and these properties are uniform independent of particular composition. Increasing Hf content while decreasing Ti increases the density and liquidus temperature of Cu-Hf-Ti alloys, while increasing Cu content decreases glass forming ability. The effect on GFA of small additions of Si, Ni, Y and Ta was evaluated. A 2 at.% addition of Y improved the GFA of the most robust bulk glass forming alloy in this series, CU57.5Hf27.5Ti15 (C) 2007 Elsevier B.V. All rights reserved.