Aluminum Alloys: Solute Atom Clusters and Their Strengthening

Benefiting from the rapid development in advanced characterization technologies, solute atom clusters in metal materials can now be quantitatively characterized in a high temporal and spatial resolution. This greatly promotes in-depth investigations on solute atom clustering. As for the widely-used Al alloys, solute atom clusters are attracting increasing attention not only as precursors for the precipitates during the aging process but also as a novel approach to strengthen and toughen the Al alloys. Experimental evidence has proved that solute atom clusters can simultaneously afford high strength and great ductility, indicating potential tailoring freedom to achieve an excellent strength-ductility combination. In this paper, the recent progress in solute atom clustering associated with Al alloys are summarized, including comprehensive characterization, thermodynamics and kinetics of formation, influencing factors, strengthening and toughening, and an application example. Ultimately, from the author.. s point of view, possible key directions for further studies of solute atom clusters are also proposed.