Pseudo-4D view of the growth and form of locked eutectic colonies

We investigate solidification of an Al-Al2Cu as a model system to understand the emergence patterns (such lamellar, rod and maze-like) within eutectic colonies. To uncover morphological transitions in-situ in 3D, we introduce here new synchrotron-based, X-ray imaging procedure. Our method simultaneously maximizes temporal (200 ms) spatial resolution ($0.69^2 \mu m^2/pixel$) over that traditional approaches. The wealth information obtained from this procedure enables us visualize development crystallographically `locked' microstructure presence thermosolutal convection. This data provides direct insight into mechanism lamella-to-rod transition accommodates fluctuations interfacial composition growth velocity. find is brought about by impurity-driven forces acting on solid-solid-liquid trijunction must overcome stiffness solid-solid interfaces. pseudo-4D strategy holds broad appeal science community, it can space-time trade-off conventional situ microtomography.