Our previous studies [19,20] show that the GB plays a very critical
role in nanoscale material, present work concentrates on further
understanding the GB effect (or grain size effect) on nanosacle hardness
and the corresponding intrinsic deformation mechanism. The
results are quite distinct from the H-P effect found in those of axial
deformation of bulk materials [6,21], and the mechanism behind
the soft response while refining the grain size under the atomic
scale indentation is discussed.