Effect of the interatomic potential on the features of displacement cascades in α-Fe: a molecular dynamics study

Depending on the interatomic potential used for molecular dynamics (MD) simulation of displacement cascades in α-Fe, primary states of damage characterised by different spatial distributions of point-defects (clustered fractions in particular) are obtained. These differences may influence the microstructural evolution predicted in damage accumulation models which make use of the input from MD cascade simulations. In this work, a number of displacement cascades initiated by recoils of energy ranging from 5 to 40 keV have been simulated in the same way using four different interatomic potentials for α-Fe, each providing, among other things, different descriptions for the self-interstitial atoms (SIA) in this metal. The behaviour of the cascades in correspondence with their different phases and the final surviving defect population have been studied using the same criteria for cascade analysis and compared. The outcome is discussed trying to identify the characteristics of the potential that mostly influence the predicted primary state of damage.