Dendritic Solidification of Metallic Alloys

When metallic alloys are cooled from the liquid, in almost all cases from castings to additive manufacturing, the metal freezes via the formation of dendrites. These crystalline structures directly impact many properties of the final bulk material. In this project, we use high resolution 4D synchrotron x-ray tomography to record dendrite growth in real time. We study how alloy composition and solidification conditions affect the dendritic morphologies, curvatures, growth velocities, solid-liquid interface areas, secondary branch spacings, and crystallographic growth directions. We have shown that a single dendritic root can have arms with tip morphologies ranging from nearly spherical to highly elliptical. We have also observed the fragmentation of dendritic arms which move both with and against gravity, indicating density changes during growth. These 4D experiments give new insights into the fundamental materials science governing the solidification of metallic alloys.

Participants

Selected Publications

K. Elder, Y.Sun, T. Stan, X. Xiao, P. Voorhees, “Microstructural Characterization of Dendritic Evolution Using Two-Point Statistics,” Scripta Materialia (2020) doi: 10.1016/j.scriptamat.2020.02.034