A new physical mechanism or mode of plastic deformation in nanocrystalline metals and ceramics was suggested and theoretically described. The mode represents the cooperative grain boundary sliding and stress-driven grain boundary migration process. It was theoretically revealed that the new deformation mode was more energetically favourable than “pure” grain boundary sliding and enhanced the ductility of nanocrystalline solids in wide ranges of their structural parameters.

Cooperative Grain Boundary Sliding and Migration Process in Nanocrystalline Solids. S.V.Bobylev, N.F.Morozov, I.A.Ovidko: Physical Review Letters, 2010, 105[5], 055504