On the minimum grain size obtainable by high-pressure torsion

Recently, a dislocation model that quantitatively relates the minimum grain size obtainable by ball milling, dmin, to several physical parameters, such as the activation energy for self-diffusion and the stacking fault energy, in a nanocrystalline (nc) material was developed. In this paper, it is shown that the predictions of the model are consistent with the characteristics of the minimum grain size, dmin, obtainable in FCC and BCC metals by high-pressure torsion. Such a consistency indicates that the dislocation model for ball milling is quantitatively applicable to the description of other severe plastic deformation (SPD) processes.