Advanced Manufacturing-Driven Multiscale Nanostructured Metals: A Review.

The rapid evolution of next-generation advanced manufacturing technologies, exemplified by additive manufacturing, has drastically expanded the accessible compositional and processing windows for metallic materials. These advances actively drive the formation of far-from-equilibrium structures and open unprecedented opportunities to design multiscale nanostructured metals with exceptional structural and functional properties. In this mini-review, we examine how multiscale nanostructural design is driven by both top-down and bottom-up advanced manufacturing routes, elucidating the underlying thermodynamic, kinetic, and geometric driving forces. Representative approaches, including severe plastic deformation for top-down and physical/chemical vapor deposition for bottom-up, are analyzed to illustrate their distinctive roles in structure formation. The ensuing discussion highlights the strengthening and toughening mechanisms of these hierarchical structures from the perspectives of microscale dislocation regulation and mesoscopic deformation coordination. Finally, we summarize the performance advantages and application prospects of multiscale nanostructured metals as well as outline future pathways toward the deeper integration of multiscale structural design with emerging manufacturing technologies.