Ab initio calculations of defects in Fe and dilute Fe-Cu alloys

Point defects in Fe and dilute FeCu alloys are, investigated by ab initio calculations based on density functional theory. The relaxed vacancy and interstitial and substitutional Cu atom formation energies are determined as well as some migration energies. The binding energies of various Cu containing defects believed to play an important role in the embrittlement of pressure vessel steels under radiation are calculated and discussed. The results are consistent with a Cu transport via a vacancy mechanism. The introduction of a Cu atom decreases the energy difference between the [110] dumbbell and the [111] dumbbell configurations, and should make the dumbbell rotation motion easier. The ab initio results are compared to the figures obtained with empirical interatomic potentials. The convergence of the results with the simulated system size is examined.