| Abstract Scope |
Large temperature gradients, high solidification velocities, and repeated cycles of heating and cooling are typically experienced during additive manufacturing (AM). Combinations of thermal gradient and solid/liquid interface velocity are known to impact microstructure (and defect) development, including potential grain refinement produced by the columnar to equiaxed transition. Thus, a deeper understanding of solidification (and solid state phase transformations, when appropriate) under AM conditions is needed to guide alloy design matched to AM processes. State-of-the-art, multiscale characterization of solidification dynamics and resulting microstructures in the context of the local conditions experienced during AM is needed to achieve this aim. New insights into microstructure development under AM conditions obtained by in-situ/ex-situ characterization of conventional alloys, model alloys, and alloys designed for AM are highlighted. Multiscale in-situ/ex-situ characterization is compared to process modeling and solidification theory and modeling, which will enable the prediction and control of metallic alloy solidification dynamics by advanced manufacturing. |