Effects of alloying elements on defect production and evolution in Fe-based alloys

Fe-based alloys are important structural and cladding materials for current and future nuclear reactors. Radiation-induced defect production and subsequent defect evolution play important roles in microstructural evolution in these alloys. In this work, the effects of alloying elements on defect production and evolution in Fe-based alloys have been investigated using molecular dynamics simulations. Primary damage simulations have been conducted for pure Fe and Fe-based alloys, including Fe-Cr, Fe-Cu, and Fe-W. It is found that Cr or Cu do not affect the total number of produced Frenkel pairs, while oversized W increases the total number of Frenkel pairs. In addition, Cr interstitials are over-produced while Cu and W interstitials are under-produced comparing to their solute concentrations. Both dislocation loops and C-15 clusters have been found in these alloys but their population is affected by the alloying elements. Interstitial cluster evolution is studied in these alloys. It is found that Cr and W suppress the growth of dislocation loops. Finally, the defect energetics are calculated to interpret these simulation results.