1. Application of models to nanostructured materials

1.1 Structural features of nanostructured materials

The essential feature of nanostructured materials is the very high proportion of the volume that is occupied by grain boundaries, and more generally by the interfaces, in relation to the volume of the grains themselves. We have here a crystalline and amorphous phase mixture. Assuming that the grains are cubic or spherical, we can estimate the volume fraction of the interfaces at 3 δ/d , δ being the thickness of the latter and d the grain size (this is the area of the periphery of a grain multiplied by half of the thickness of the boundaries and divided by the volume of the grain). Assuming that ...