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 sizedependent 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.