Dislocations are line defects within the atomic arrangement of crystalline materials, notably metals. Irreversible deformation, or plasticity, of these materials is closely linked to the presence of dislocations, acting as local mediator of shearing motion within the crystal. Upon deformation, dislocations migrate through the crystal and agglomerate into micrometre-sized structures. These structures are understood to govern the nature of deformation processes as their evolution and morphology is tightly correlated with the applied deformation.

Traditionally, dislocation structures have been mainly studied using Transmission Electron Microscopy (TEM) necessitating thin foil specimens with a thickness of approx. 200 nm which limit access to volumetric information and dynamics. Consequently, the physics behind the formation and refinement processes of dislocation structures have remained elusive.

Dark-field X-ray Microscopy enables imaging individual dislocations deeply embedded in millimetre-sized specimens. In this talk, we will present a deformation-resolved movie of a three-dimensional dislocation configuration rearranging under a gradually applied external load. Through this, we identified individual dislocation lines and reconstructed the evolution of their three-dimensional network. These new insights are expected to enhance our understanding of the physics of plasticity and bridging the gap between atomic-scale rearrangements and macroscopic deformation.