Annihilating dislocation loops in irradiated zirconium alloys under pulsed electric current to eliminate radiation hardening

Dislocation loops generated by irradiation in service environments are one of the primary factors that cause hardening and embrittlement of zirconium alloys, which are commonly used as nuclear fuel cladding materials. The rapid elimination of dislocation loops in irradiated materials is of great significance for restoring their properties. Zirconium alloys with high-density dislocation loops induced by ion irradiation were studied by pulsed electric current. The results demonstrate that pulsed electric current treatment at 450 °C significantly eliminates dislocation loops in the irradiated material, reduces their number density, and achieves a 94.2% reduction in the irradiation-induced hardness increment, effectively restoring the alloy's mechanical properties to near-original levels. In the time dimension, compared with isothermal heat treatment, the efficiency of pulsed electric current in eliminating irradiation hardening is increased by three orders of magnitude. Molecular dynamics simulations of dislocation loop evolution demonstrate that the pulsed electric current enhances the local potential energy of the dislocation loops, accelerates atomic diffusion within the dislocation loop regions, thus promoting their annihilation, which ultimately facilitates the recovery of radiation-damaged properties. This work provides a novel pathway for irradiation damage recovery in nuclear materials.