Thermal Properties of Cu-Hf-Ti Metallic Glass Compositions

Abstract

ABSTRACTThe glass transition temperature Tg, crystallization temperature Tx, solidus temperature Tm, and liquidus temperature Tl, of a number of ternary Cu-Hf-Ti glassy alloys in the composition range of 51< Cu <67, 5 < Hf < 40 and 5 < Ti <40 (at.%) are reported and discussed. It is found that increasing the Ti:Hf ratio results in a rapid decreasing of Tg and Tx. This behavior is related to the fact that the melting point and cohesive energy for Ti are substantially lower than for Hf. The solidus temperature Tm, remains relatively constant on a wide range of compositions. The liquidus temperatures data suggest a ternary eutectic within the compositional field encompassed by the Cu55Hf20Ti25, Cu59Hf21Ti20, Cu60Hf20Ti20 and Cu55Hf21Ti24 alloys, with a liquidus temperature, Tl, of ∼1170 K; this is supported by the DTA traces, which show a single melting peak. Based on the DTA analysis, the experimentally calculated liquidus projection for the ternary Cu-Hf-Ti alloy system is also reported.