fig1
From: Nanostructural design of superstrong metallic materials by severe plastic deformation processing
Figure 1. Two types of Hall-Petch slopes within different characteristic length scales: dcr1 - grain size, below which the contribution of nanostructural features (nanoparticles, substructure and others) becomes significant in the strengthening of SPD-processed materials; dcr2 - grain size, below which the contribution of grain boundary segregation and non-equilibrium grain boundaries becomes significant in UFG materials. Reproduced with permission, Copyright 2013, John Wiley and Sons[5].
