Atomic characteristics of heterogeneous nucleation during solidification of aluminum alloys: A critical review

Abstract

Solidification is a critical process in the manufacturing of metals and alloys, with nucleation being the initial stage that determines the resulting microstructure and mechanical properties. Among various nucleation methods, heterogeneous nucleation is particularly effective in controlling the solidified structure and properties. However, the underlying mechanisms and atomic characteristics of heterogeneous nucleation remain a topic of debate. This paper reviews recent advancements and the current state of research on heterogeneous nucleation during the solidification of aluminum alloys. It focuses on three key areas: the methods and mechanisms for influencing heterogeneous nucleation, existing theories on the subject, and recent experimental and modeling studies on the effect of atomic-scale interactions at the solid/liquid interface on nucleation. The paper also addresses the ongoing challenges and future directions, highlighting the importance of atomic-scale experimental characterization, the validity and reliability of atomic-scale simulations, the role of the pre-nucleation layer at the solid/liquid interface, and the impact of solute elements on the formation of the pre-nucleation layer.