Thermal evolution and high temperature annealing of dislocation microstructure
of an irradiated metal, described by an ensemble of interacting interstitial
dislocation loops, is explored using discrete dislocation dynamics simulations.
On the microscopic scale, the two fundamental processes driving microstructural
evolution are the pipe diffusion of atoms along the dislocation lines, resulting
in dislocation self-climb, and bulk diffusion of vacancies resulting in the conventional
dislocation climb. Simulations show that the coalescence and coarsening
of prismatic dislocation loop microstructure observed at lower temperatures is
driven primarily by dislocation self-climb. In tungsten, dislocation self-climb
gives rise to a pronounced change in the dislocation loop microstructure at temperatures close to 800 0C ,
whereas the same microstructural transformation in iron is predicted to occur at 270 0C.