Synergistic effects of applied strain and cascade overlap on irradiation damage in BCC iron

Abstract

Irradiation-induced damage accumulation in BCC iron under an applied mechanical strain was investigated using molecular dynamics (MD) simulations. We found that the application of tensile and compressive strains affects defect accumulation and cluster formation, albeit according to different mechanisms. At low doses, radiation damage in the form of point defect formation was dominant, while at high doses, large cluster formation dominated, in which the diffusivity D and binding energy Eb of the defects became important. The applied strain was found to result in monotonic decrements of the formation energy Ef of the Frenkel pair, leading to an increment in defect production with an increase in the applied strain at low doses. However, at high doses, both the compressive and tensile strains enhanced damage accumulation and promote the clustering process through competition between defect formation, diffusion, and binding. We believe our results will aid in providing a fundamental mechanistic understanding of the effects of strain on damage accumulation under high-dose irradiation.