2. Properties of nano-objects

The aim of studying the mechanical behavior of materials is to determine their response (deformation, fracture, etc.) to a given stress. The stress-strain curve of a material is generally characterized by an elastic part (linear relationship between stress and strain), a plastic part (non-linear relationship) and then fracture. The elastic/plastic limit corresponds to the movement of dislocations, and fracture to the propagation of a crack, generally initiated by a defect (figure 3 ).