Thermal Stability and Phase Transformation in Hfl-xCux Metallic Glasses

Abstract

ABSTRACTIn this paper we report the difference in the structures, physical properties and thermal behaviors of two compositions of amorphous Hf-Cu. One (Hf50CU50) is near the eutectic composition and the other (Hf67Cu33) corresponds to an intermetallic compound. Transmission and scanning electron microscopy (TEM, SEM), differential scanning calorimetry (DSC), electrical resistivity and high-angle X-ray diffraction have been used to study these glasses in detail. Amorphous Hf67 Cu33 is structurally stable up to the crystallization temperature, while Hf50 Cu50 undergoes a ductile to brittle transition associated with a chemicai phase segregation at temperatures far below the glass transition. An anomalous behavior in the resistivity is associated with this phase transformation.