  In recent years it has become possible to study the properties of
nanocrystalline metals through atomic-scale simulations of systems with
realistic grain sizes. A brief overview of the main results is given, such as
the observation of a reverse Hall-Petch effect - a softening of the metal when
the grain size is reduced. The limitations of computer simulations are
discussed, with a particular focus on the factors that may influence the
reliability of this kind of simulations.
