Dynamics of solidification in Al thin films measured using a nanocalorimeter

Abstract

We demonstrate how a nanocalorimeter can be used to measure the dynamics of thin film melting and solidification using aluminum as a model system. Recalescence, a rise in temperature due to enthalpy release on solidification, is observed when the rate of heat release is faster than the rate of heat extraction. For thin films, with a large density of nucleation centers at the interface, recalescence effects are observed at high cooling rates where direct measurements of heat capacities and enthalpy changes are challenging. Temperature rates of 104 K/s were applied using nanocalorimeter chips; the nanocalorimeter allows direct measurement of the under cooling, temperature rise during solidification, and the associated changes in enthalpy. This work highlights some of the challenges recalescence causes in physical measurements and provides a numerical strategy to evaluate enthalpy changes during rapid solidification.