<i>Ab initio</i> study of thermodynamics of radiation produced solute clusters in reactor pressure vessel steels

Using ab initio calculations on the coherent solute clusters produced by irradiation in the body-centered cubic (bcc) Fe matrix, this study examines the interaction between solute elements and the role of such thermodynamics in the solute clustering in reactor pressure vessel steels. The results indicate that Ni and Mn exhibit an attractive synergy effect, maintaining a 1:1 compositional ratio in the growing solute clusters. Si energetically prefers the Fe matrix over the Cu cluster. What is more, Ni, Mn, Si atoms within the solute clusters can be mobile, allowing rearrangement. These findings rationalize the existing literature data, which show systematic variations of chemical composition of solute clusters in neutron irradiated reactor pressure vessel materials, and throw light on the role of thermodynamics under irradiation.