Kinetic Monte Carlo Annealing Simulation of Cascade Damage in α-Fe

Molecular dynamics is a useful tool for simulating cascade damage in metals and alloys, but the time scale accessible to molecular dynamics is only about 10 -10 s. Kinetic Monte Carlo can be used to simulate annealing of cascade damage to permit analysis of the longer time evolution of cascade damage. We conducted a series of such annealing simulations in α-Fe. The number of surviving displacements before annealing is ~0.3 of the Norgett-Robinson-Torrens (NRT) value in the case of primary knock-on atoms with energy more than ~10 keV, and it decreased by ~30% during the annealing at 300 K because of recombination of vacancies and self-interstitial atoms. The recombination ratio increased as the annealing temperature increased. These results can be meaningfully applied in models such as mean field reaction rate theory used to simulate long-term radiation damage accumulation. We also demonstrated that 1D motion of small SIA clusters can substantially influence the long-term accumulation of cascade damage.