Thermal analysis of undercooled metallic liquids by electromagnetic levitation drop calorimetry

Here the role of thermodynamic measurements in computational materials science (with a focus on metallic glasses) is described, of which the heat capacity of the undercooled liquid is identified as a key measurement. Traditional experimental techniques for generating thermodynamic measurements are then reviewed, as well as techniques that focus on the undercooled liquid. Then the development of a levitation calorimeter is presented, and the results of applying the technique to several binary Al-based glass forming compositions is described. The enthalpy of a reactive Al-rare earth liquid was measured as well as the enthalpy of the undercooled liquid of Al-rare earth glass forming compositions. The results indicated a constant heat capacity of the liquid throughout the temperature range studied, which is discussed with respect to liquid behavior. Additionally, the containerless levitation technique enabled the in-situ formation of metastable Al-Sm phases.