Effect of lead atom penetration on displacement cascade in bcc iron studied by molecular dynamics simulation

Abstract Displacement cascades in bcc Fe-Pb solid solution are studied by molecular dynamics (MD) simulations. The Fe-Pb alloy model with different Pb concentrations was set as the Pb penetration structure of iron-based materials in actual working conditions. The results show that Pb atom penetration enhances the radiation damage of displacement cascades in Fe. The number of stable point defects in Fe-Pb alloy increases significantly, varies with Pb concentration and PKA energy. The differences of defect recombination rate are obvious under different Pb concentrations. Point defect analysis results indicate that there are rules in the relation between the interstitial and vacancy of two elements. Besides, unconnected cascade collision is found in Fe-Pb model under 10 keV, and the size of the subcascade affects the formation of cluster. The cluster results show that the interstitial form clusters easier and larger than vacancy, the PKA energy and Pb concentration can influence the size of clusters.