Eutectic Growth and Dendrite Formation in Aluminum Alloys

This lecture discusses the eutectic growth and dendrite formation in aluminum alloys, particularly focusing on the Al-33% Cu alloy. It begins with the visualization of dendrites using succinonitrile and acetone, referencing key studies and sources. The instructor explains the eutectic growth process, where two phases, primary Al and Al₂Cu, grow simultaneously, forming a eutectic structure. The lecture covers the mechanisms of growth and diffusion, emphasizing the importance of solute evacuation during solidification. The relationship between solidification speed and microstructure scale is highlighted, indicating that faster solidification leads to finer structures. The concept of capillarity and maturation is introduced, illustrating how pressure differences affect the stability of structures. The lecture concludes with an overview of microsegregation in solidified alloys, demonstrating how solidification can lead to concentration gradients and the presence of unexpected phases. This comprehensive examination of aluminum alloy microstructures provides valuable insights into material science and solidification processes.