Origin of glass forming ability of Cu-Zr alloys: A link between compositional variation and stability of liquid and glass

Abstract

Here, we provide a link which shows how the compositional change affects the liquid and glass stabilities by measuring temperature-time transformation (TTT) diagram of Cu-Zr alloys, revealing the origin of glass forming ability (GFA) with composition. From the TTT study, we find that the compositional change yields a different origin of GFA for the three best bulk metallic glasses $({\mathrm{Cu}}_{64}{\mathrm{Zr}}_{36},{\mathrm{Cu}}_{56}{\mathrm{Zr}}_{44}$, and ${\mathrm{Cu}}_{50}{\mathrm{Zr}}_{50})$ due to varying stabilities of liquid and glass, which explains maxima observed in undercoolability, persisting time at nose temperature, and crystal-liquid interfacial free energy.