Deformation mechanisms, microstructural evolution and mechanical properties in small-scaled face-centered-cubic metallic thin films

Metallic thin films have attracted much attention owing to their unique mechanical properties, which are widely used in micro-/nano-devices. In this review, several key topics about the thin films in the micron to nano-scales are covered. First, the plastic deformation mechanisms in face-centered-cubic (FCC) metals, in particular the size-dependent deformation twinning at small scales, are discussed based on a deformation-mechanism map. Microstructural evolution is then briefly discussed from the perspective of the ratio of effective-to-internal stresses, while the stress-driven grain growth is discussed based on a twinning-mediated mechanism. The last section elucidates the size-dependent mechanical properties of metallic thin films, such as yield strength, ductility and mechanical fatigue behavior.