Yh. Wen et al., The influence of grain size and temperature on the mechanical deformation of nanocrystalline materials: Molecular dynamics simulation, CHIN PHYS, 10(5), 2001, pp. 407-412
Nanocrystalline (nc) materials are characterized by a typical grain size of
1-100nm. The uniaxial tensile deformation of computer-generated nc samples
, with several average grain sizes ranging from 5.38 to 1.79nm, is simulate
d by using molecular dynamics with the Finnis-Sinclair potential. The influ
ence of grain size and temperature on the mechanical deformation is studied
in this paper. The simulated nc samples show a reverse Hall-Petch effect.
Grain boundary sliding and motion, as well as grain rotation are mainly res
ponsible for the plastic deformation. At low temperatures, partial dislocat
ion activities play a minor role during the deformation. This role begins t
o occur at the strain of 5%, and is progressively remarkable with increasin
g average grain size. However, at elevated temperatures no dislocation acti
vity is detected, and the diffusion of grain boundaries may come into play.