Dendritic Growth: Microstructure in Metal Solidification

This lecture discusses the solidification of metals, focusing on dendritic growth and its implications for microstructure. It begins with a review of foundry processes, including ingot casting and lost wax casting, emphasizing the importance of mold design and thermal management. The instructor explains the conditions that favor different types of dendritic growth, such as columnar and equiaxed structures, and introduces the concept of constitutional undercooling. The competition between these growth forms is analyzed, particularly in the context of the columnar-to-equiaxed transition (CET). The lecture also covers the microstructural characteristics of welding and 3D printing, highlighting how processing parameters influence the resulting grain structures. The instructor concludes by summarizing the key factors affecting dendritic growth and the challenges in achieving desired microstructures in various manufacturing processes.