Multiple cascades regime in fcc metals. Molecular dynamics simulations and calculated HREM imaging

This study presents a simulation method which consists of three parts. The first one is classic molecular dynamics and is used to evaluate disordered atomic configurations. The second one is an evaluation of the electronic charge configuration of the type extended Debye-Hueckel. The third one calculates the HREM image of the lattice structure obtained from molecular dynamics. The simulation method is applied to collective motions of PKAs displaced in a fcc lattice with energies near the displacement threshold. These conditions, which represent in a simplified manner e ^- irradiation, are aimed at investigating whether the defect growth kinetics shows ordering phenomena similar to the ones studied in phase transition. Embryonic forms of ordered interstitial agglomeration and unusual oscillatory behaviours of recrystallization are observed. The HREM calculations show that disorder is visible during its entire evolution.