Fast scanning calorimetric study of nucleation rates and nucleation transitions of Au-Sn alloys

Fast scanning (or chip-) calorimetry has been applied to systematically investigate the nucleation kinetics of two near eutectic Au-Sn compositions. The determined nucleation rates show a maximum at finite undercooling. A comparison of the experimental data with model calculations indicates that the observed maxima of the nucleation rates are due to a transition of the nucleation mechanism in the deeply undercooled liquid.