Interactions of Dislocations with Twin Boundaries in Hard-Sphere Colloidal Crystals

The interaction of dislocations with twin or grain boundaries is a key factor in understanding the strength and strain hardening of crystals. Confocal tracking of particles in a colloidal crystal allows a detailed look at the mechanisms of such interactions at the particle scale, analogously to what happens on the atomic scale in conventional crystals. The grain boundaries are prepared by sedimentation onto templates in the [110] $\Sigma $3 orientation. A complex set of interactions is observed: additional twinning, the emission of a pair of partial dislocations, and the formation of kinks in the original twin boundary.