  Molecular dynamics (MD) simulations have been performed to investigate the
fatigue deformation behaviour of polycrystalline Cu with grain size of 5.4 nm.
The samples were prepared using Voronoi algorithm with random grain
orientations. Fatigue simulations were carried out by employing fully reversed,
total strain controlled cyclic loading at strain amplitude of $\pm4$\% for 10
cycles. The MD simulation results indicated that the deformation behaviour
under cyclic loading is dominated by the slip of partial dislocations enclosing
the stacking faults. At higher number of cycles, the grain boundary migration
leading to coarsening of larger grains at the expense of the smaller grains has
been observed. The cyclic stress-strain behaviour, the deformation mechanisms
and the variation of dislocation density as a function of cyclic deformation
have been discussed.
