Molecular dynamics simulations of the evolution of primary radiation damage in Ti-6Ta alloy for spent nuclear fuel reprocessing

Abstract

Ti-6Ta (in wt%) alloy is extensively used in critical components for nuclear spent fuel reprocessing due to its excellent mechanical and resistance to boiling nitric acid corrosion properties. However, the study of defect formation and evolution mechanisms under irradiation conditions is still limited. This study employs molecular dynamics simulations to investigate the evolution of irradiation damage in Ti-6Ta alloy and compares its irradiation resistance mechanisms with those of pure Ti. Isothermal and differential temperature simulations were performed on primary knock-on atom with energies ranging from 1 to 20 keV to understand the irradiation resistance of Ti-6Ta alloy. During the thermal peak stage, Ti-6Ta alloy exhibits a higher number of displaced atoms, but fewer surviving defects after relaxation and recombination. After irradiation stabilization, Ti-6Ta alloy is less likely to form large defect clusters, and Ta atoms tend to appear in these larger clusters. As the temperature increases, tantalum atoms gradually appear in the defect clusters of the low Primary Knock-on Atom (PKA) energy system. Elevated temperatures enhance defect recombination rates and further reduce the migration effects of irradiation-induced defects.