Temperature Dependence of Defect Production Efficiency in α-Fe

Abstract

Advanced high-strength steels are being considered for various next generation nuclear reactor components due to their relatively good neutron transparency and thermo-mechanical stability. In the current study, we generate comprehensive displacement cascade defect statistics for α-Fe by considering temperatures between 15 and 1200 K, PKA energies between 0.1 and 20 keV and three interatomic potentials. The data is analyzed in terms of the defect production efficiency η, which is a measure of the severity of primary displacement cascade damage and is defined, from molecular dynamics simulations, as the number of surviving Frenkel pairs observed from simulation relative to the number of stable Frenkel pairs predicted from the Norgett-Robinson-Torrens (NRT) model. Previous studies have revealed that η is independent of interatomic potential and temperature and exhibits power-law dependence with PKA energy. Our results contrast with previous studies, as η is shown to be temperature dependent. This temperature dependence can be attributed to defect recombination, which is a thermally activated mechanism. Based on our findings, we propose an extended power-law representation for η, which accounts for the influence of both temperature and PKA energy.