This nugget was featured in Imago's 2006 Calendar.
This LEAP tomography data set is from a dilute Al-Sc-Yb alloy which has been aged at 300°C. Nanosize Al3(Sc1-xYbx) precipitates (L12 structure) improve the strength and creep resistance of Al. Yb segregates to the center of the precipitates while the Sc segregates around the Yb core. The green spheres represent Yb atoms and the blue spheres represent Sc. Blue and green surfaces represent isoconcentration surfaces of Sc and Yb. Al atoms omitted for clarity.