ABSTRACT
NANOCRYSTALLINE (nc) materials are characterized by grain sizes < 100 nm.
Because of the small grains of nc-materials, grain boundaries, junction lines, and
nodes have significant volume fractions, a characteristic that can influence properties
far more strongly than in conventional materials.
Nanocrystalline materials offer interesting possibilities related to many structural
applications. In order to explore some of these possibilities, an understanding of the
origin and nature of deformation processes in nc-materials is essential. Accordingly,
the objective of this presentation is two-fold: (a) to identify the requirements that a
deformation mechanism should meet in terms of accounting for the mechanical
characteristics and trends that are revealed by the experimental data reported for ncmaterials;
(b) to propose a deformation mechanism that not only meet these
requirements but also avoid various problems associated with available deformation
mechanisms.