Progress in Strengthening and Toughening Mechanisms of Heterogeneous Nanostructured Metals

Heterostructured metals typically exhibit excellent mechanical properties, such as high strength, plasticity, and fracture toughness, which are not present in conventional homogeneous materials. This is primarily due to the synergistic effects arising from the interactions between the internal components including the stress/strain gradients, geometrically necessary dislocations, and unique interfacial behavior. This study focuses on two typical heterogeneous nanostructures (laminated and nanotwinned) by reviewing the recent progress in their strengthening and toughening mechanisms. The analysis highlights the effects of the properties and sizes of the individual components, interfaces, and loading directions on the macroscopic strengthening and toughening behavior.