Solute - ⟨111⟩ interstitial loop interaction in α-Fe: A DFT study

Density functional theory calculations of the interaction of solute atoms with < 111 > SIA loops in Fe have been performed in large supercells. Using the data obtained, it is shown that for the pressure vessel steel solute concentration, and under equilibrium conditions, a large amount of P, Si and Mn atoms can be found inside the loops, close to its border. A lower amount of Cu would be found mostly outside the loop, whereas Cr would be neither inside nor outside the loop. No solute segregation is predicted in the center of the loop in agreement with the toroidal picture one associates with these loops. Ni and Mn tend to enhance the interaction of other solutes with the loop and the strain contributes to enhancing the chemical interaction for these two elements which can shed light on the formation of the so-called late blooming phases in RPV steels. Interatomic potentials predictions are quite poor except for the Fe-P interatomic potential derived by Ackland et al. [1]. (C) 2017 The Authors. Published by Elsevier B.V. All rights reserved.