Nanograin nucleation initiated by intergrain sliding and/or lattice slip in nanomaterials

摘要

Stress-induced nucleation of nanoscale grains (nanograins) in deformed nanocrystalline metals and ceramics is theoretically described as a process initiated by intergrain sliding and/or lattice slip. The nanograin nucleation occurs through splitting and migration of grain boundaries containing disclination dipoles produced by intergrain sliding and/or lattice slip. It is shown that the nanograin nucleation is energetically favorable in mechanically loaded nanocrystalline Al and α-Al_2O_3 in certain ranges of their parameters and the external stress level.