It was recalled that solute Cu played a major role in the embrittlement of reactor pressure vessel steels under irradiation. In such steels, and in dilute FeCu alloys, the tomographic atom probe had revealed the formation of Cu atmospheres under neutron flux. It was thought that a role was also played by other solutes (Ni, Mn, Si) which were within the atmospheres. In order to understand the elementary mechanisms behind the formation of these atmospheres, an investigation was made – using ab initio calculations based upon density functional theory – of the interactions of point defects in dilute Fe-X alloys (where X was Cu, Mn, Ni or Si). The structure of X-vacancy complexes was determined, as well as their binding energies. Their relative stability was and compared with experimental results obtained from model alloys.

Ab initio Calculations of Vacancy Interactions with Solute Atoms in BCC Fe. E.Vincent, C.S.Becquart, C.Domain: Nuclear Instruments and Methods in Physics Research B, 2005, 228[1-4], 137-41