Strength-ductility synergy via cryogenic severe plastic deformation in an Al–Mg alloy achieved by clustering-induced strengthening

Utilizing excess vacancy to form effective solute clusters has been considered as a potential strategy to strengthen Al alloys. Herein, we designed a cryogenic submerged friction stir processing, by the one-step process in a short time, to realize the coexistence of grain refinement, high-density clusters, and nanoprecipitates, thus enhancing strength and ductility simultaneously. The atomic information showed the unique formation of high-density clusters (1 ∼ 2 nm), which was related to the strain-induced migration of solute atoms. This study may provide a new strategy for alloys with low alloying content that can be enhanced by forming solute clusters.