Electronic effects on radiation damage in α-iron: a molecular dynamics study

Abstract

Widely used as structural materials in nuclear reactors, iron (Fe) -based alloys experience significant changes in their microstructure and macroscopic properties under high flux neutron irradiation during operation, posing issues associated with the safe operation of nuclear reactors. In this work, a molecular dynamics simulation approach incorporating electronic effects was developed for investigating the primary radiation damage process in α-Fe. Specifically, the influence of electronic effects on the collision cascade in Fe was systematically evaluated based on two commonly used interatomic potentials for Fe. The simulation results revealed that both electronic stopping (ES) and electron–phonon coupling (EPC) contribute to a reduction in the number of defects in the thermal spike phase. The application of ES decreases the number of residual defects after the cascade evolution, whereas EPC has a reverse effect. The introduction of electronic effects promotes the dispersive subcascade formation: ES significantly alters the geometry of the damaged region in the thermal spike phase, whereas EPC mainly reduces the extent of the damaged region. Furthermore, the incorporation of electronic effects effectively mitigates the discrepancies in simulation outcomes when using different interatomic potentials.