The interaction of P atoms and radiation defects with grain boundaries in an alpha-Fe matrix

Classical molecular dynamics simulations have been employed to investigate the influence of P impurity atoms close to grain boundaries in α-Fe. Static calculations have been performed to determine the energetics of P and Fe defects in the grain boundary region for three symmetrical tilt grain boundaries, Σ5(3 1 0)[0 0 1], Σ41(9 1 0)[0 0 1] and Σ25(4 3 0)[0 0 1]. The simulations are carried using two different embedded atom Fe potentials, one of which includes the effect of second nearest neighbours. Both potentials produce quantitatively and qualitatively similar results for the static calculations. It has been shown that P atoms preferrentially segregate to the free volume region in the grain boundary plane. For collision cascade simulations the second nearest-neighbour model is found to predict a higher number of cascade defects in an irradiated perfect Fe matrix.