For most of metallurgical history, solidification velocities were measured in microns to millimeters per second. Modern advancements like high energy density welding and additive manufacturing have raised relevant velocities to as high as two meters per second. Rapid solidification affects how microstructural patterns form and enables the formation of unique structures. This presentation will discuss the microstructures that develop during rapid solidification in the Al-Ag and Al-Cu systems. The solid-state behavior of these systems has been extensively studied, but their behavior during rapid solidification is drastically different. Alloy composition controls the velocity thresholds where different patterns form, and new formulae are needed to accurately predict these transitions. In addition to their aesthetic and scientific merits, the solidification patterns formed at high velocity offer opportunities for enhanced properties and easier solid-state processing.
