Molecular dynamics simulations were used to investigate the effects of electron-phonon coupling upon the defect production and clustering that occurred in the primary cascade state of neutron-radiation damage in the a-phase. A simplified physical model for electron-phonon coupling was incorporated into a hybrid continuum cum molecular dynamics code which permitted heat transfer from phonons to electrons. This was used to study defect generation, as a function of the strength of electron-phonon coupling, for cascade energies of 2, 5 and 10keV. The number of point defects that was produced in the primary damage state increased with increasing strength of electron-phonon coupling. Most of the additional defects formed in the cascade core, but the fraction of interstitials in clusters remained almost constant. These effects arose from a reduced mobility of atoms in the shorter thermal spike. The quenched-in clustering of vacancies played a role in the increase in vacancy clustering fraction with increasing strength of electron-phonon coupling. This mechanism was predicted to inhibit the formation of dislocation vacancy loops. The strong coupling therefore reduced the probability of loop formation.

The Effects of Electron-Phonon Coupling on Defect Production by Displacement Cascades in a-Iron. F.Gao, D.J.Bacon, P.E.J.Flewitt, T.A.Lewis: Modelling and Simulation in Materials Science and Engineering, 1998, 6[5], 543-56