fig1

Figure 1. Heterostructures in metallic materials^[18] (A and B) Primitive heterostructures, typical gradient structure (A) and lamellar structure (B), thick dull-red lines: hetero-zone boundaries; NG: nano-grain; CG: coarse grain. (C) Sub-primitive heterostructures with substructures with the low-angle grain boundary (LAGB), nano-twin (NT), nano-precipitate (NP), and chemical short-range order. (D) Composite heterostructures with dual gradients: dual-gradients in both grain size and nano-twin (left)/nano-precipitate (right). (Reprinted from Ref.^[18], with permission from Acta Metallurgica Sinica).