A probabilistic coupled hardening model of double irradiation defects in iron

Abstract

Irradiation hardening effect is of significance to the design and life extension of nuclear materials. Although various types of defects coexist under in-pile condition, most irradiation hardening models like the dispersed barrier hardening (DBH) model ignore their strength difference and treat them as a single defect type. In this work, the barrier strengths in presence of combined 〈111〉 and 〈100〉 loops in bcc iron are investigated using discrete dislocation dynamics simulations. Considering the coupling effect, the non-periodic distributed effect is preliminarily analyzed. A probabilistic model accounting for their coupled hardening effect is established based on dislocation depinning mechanism from simulation results, which can be also integrated into the modified DBH model using an effective barrier strength factor. The model presents good agreements with experimental results of iron alloy, and exhibits potential applicability in predicting the coupling effects of other defect types, including the dislocation loops and voids.