We often use dumbbells to strengthen our muscles. Mg2Si particles composed of dumbbells can also significantly strengthen metallic alloys. The image shows beautiful arrangement of Mg and Si atoms in the form of dumbbells in a Mg2Si particle in additively manufactured Al-Mg-Si alloy. Yellow and blue circles indicate Mg and Si atoms within unit cells generating entire crystal by translation along principal directions (arrows). The lateral distance between two dumbbells is 4.6 angstroms. The image was acquired with a probe-aberration corrected transmission electron microscope (Titan). Just see that heavier Si atoms appear brighter compared to lighter Mg, that’s Z-contrast microscopy.