A simple mechanical model for grain boundary sliding in nanocrystalline metals

In this paper we consider grain boundary sliding as a dominant mechanism of plasticity in nanocrystalline metals. A mechanical model for barrier resistance to sliding has been proposed. Characteristic time of plastic relaxation due to grain boundary sliding has been estimated based on molecular dynamics simulation data. At quasi-static deformation yield strength is determined by barrier resistance, and the predicted threshold stresses are in good agreement with experimental data.

► Grain boundary sliding is dominant mechanism of plasticity in nanocrystalline metals.
► Viscosity of grain boundaries and barrier resistance to sliding determine the yield strength.
► Barrier resistance makes dominant contribution in yield strength at low strain rates.