  Grain boundaries are thermodynamically unstable. Hence, their properties
should be path-dependent: grain boundaries in nanocrystals prepared using
different methods might exhibit different properties. Using molecular dynamics
simulations, we investigated grain boundaries of nanocrystals formed by
quenching,solidification with pre-induced nucleation sites, and Voronoi
tessellation. Some properties were found to be path depend: the quenched model
has lower boundary energy per atom, smaller boundary excess free volume per
atom, and slower grain growth than the Voronoi model. We surmise that these
differences are attributed to the abundant annealing twins in the quenched
model. On the other hand, other properties are path independent, such as
Young's modulus, Poisson's ratio, and the ratio between grain boundary energy
and boundary excess free volume. The results of this study further the
understanding of the structural-property relationship of nanocrystals and
provide guidance to future simulation-based studies of nanocrystalline
materials.
