Dislocation emission from deformation-distorted grain boundaries in ultrafine-grained materials

Emission of lattice dislocations from grain boundaries (GBs) specified by deformation-distorted structures with periodic fluctuations of misorientation in deformed ultrafine-grained (UFG) materials is theoretically described. It is theoretically revealed that (i) the dislocation emission from deformation-distorted GBs is significantly enhanced as compared to that from structurally equilibrated GBs; and (ii) the enhancement effect depends on the parameters specifying the deformation-distorted GBs. The influence of deformation-distorted GBs as dislocation sources on the tensile ductility of UFG materials is discussed.