Temperature dependent specific heat measurements of equilibrium, supercooled liquid, glass, and the corresponding crystal of Cu47Zr47Al6 from terrestrial and microgravity experiments on the International Space Station

Abstract

The temperature dependent specific heat, $C_p\left(T\right)$$C_p\left(T\right)$, is one of the most important thermodynamic properties of any material. Although this is routinely measured for glasses near and below the glass transition temperature, $T_g$$T_g$, very few experimental data exist for supercooled liquids between $T_g$$T_g$ and the liquidus temperature, $T_l$$T_l$. Such measurements are reported here for a good bulk metallic glass, Cu₄₇Zr₄₇Al₆, using conventional calorimetry on earth and modulation calorimetry aboard the International Space Station (ISS) on levitated solid and liquid samples. These data enable a complete thermodynamic characterization of this alloy in the crystal, glass, and the supercooled and equilibrium liquid phases. With these data it is possible to estimate the heat of fusion, driving free energy for crystallization, critical thickness, and fragility of the metallic glass.