HREM study of the microstructure in nanocrystalline materials

Abstract

High resolution electron microscopy studies of nanocrystalline Pd and (Fe 0.99, Mo 0.01) 78Si 9B 13 indicate that the atomic structures of the grain boundaries consist of both ordered and disordered regions. The microstructure in ordered regions of the grain boundaries shows curved and little distorted appearance. In some areas, however, nanovoids and imperfect or disordered regions are also observed at the grain boundaries. The defects in the grains, such as five-fold twins, edge and 60° dislocations, are also observed. The nature of these defects is similar to those normally observed in conventional coarse-grained polycrystals.