X-ray tomography using synchrotron radiation with 1-µm beam resolution at European Synchrotron Radiation Facility was used to generate three-dimensional (3-D) images for rapidly solidified 660 µm A14.3 wt pct Cu and 500 µm Al17 wt pct Cu atomized droplets. Based on the observation of microstructural features in the 3-D images, physical phenomena of rapid solidification such as nucleation and initial growth, recalescence, and porosity were apparent and are reported. A single nucleation site was observed and the coordinates of this single nucleation site were evaluated. The volume fraction of the initial growth regime and recalescence during solidification was successfully quantified. It was also possible to semiquantitatively explain the porosity distribution within the droplets. These observations will be used to present a description of the sequence of the solidification events in these droplets.