Mechanics of fracture in nanometer-scale components

Nanometer-scale components (nano-components) often exhibit characteristic mechanical behavior different from those of bulk counterparts. In this paper, we review a series of experimental studies on the mechanics of their fracture focusing especially on the interfacial strength in the nano-components, which consist of dissimilar nano-layers. Since the stress concentrated region is proportionally scaled down for shrinkage of component size, it becomes a few nanometers or at most a few tens of nanometers in the nano-components. We particularly pay attention to the availability of "stress" as the governing quantity of cracking, which is on the basis of the concept of continuum mechanics. We also investigate the effect of nano-scale stress concentration on the fatigue behavior of metals in nano-components. Finally, we discuss future directions on the further experimental exploration on the fracture mechanics in nano-components; the tensile testing of nano-rod and the fracture due to the stress concentration in the single nanometer scale.