In situ phase separation and flow behavior in the glass transition region

The temperature dependence of length change and viscous flow of the Cu₃₆Zr₄₈Al₈Ag₈ glassy alloy is examined in both the glass transition and supercooled liquid regions. Moreover, this alloy is found to exhibit phase separation rather by binodal mechanism in the glassy phase prior to crystallization. There is an apparent decrease in viscosity observed upon crystallization that is connected with the densification of the sample, but the intrinsic viscosity does not rise significantly until the initial crystallization process is almost complete. During the process the partly crystallized supercooled liquid still behaves like a fluid until a large fraction of the crystalline phase (∼90%) is formed. This new insight on flow behavior opens up possibilities for innovative processing of precise bulk shapes with high nanocrystal densities.