Improvement in radiation resistance of nanocrystalline Cu using grain boundary engineering: an atomistic simulation study

Radiation damage in the nuclear structural components is a stochastic phenomenon in both length and time scales. In this work, molecular dynamics-based numerical simulations were employed to model and investigate the primary radiation damage within irradiated Cu specimens. Here, a single-crystal Cu specimen and two nanocrystalline specimens: hexagonal columnar grain Cu specimen with n-ary sumation 3 and n-ary sumation 9 GBs (CG Cu) and Cu specimen randomly oriented grain boundary (GBs) (RG Cu), were irradiated at 600 K at primary knock-on atom (PKA) energy magnitudes, E-PKA = 10 keV, 20 keV, 30 keV, respectively. The equilibrium part of the long-range Finnis-Sinclair (FS)-type interatomic potential was smoothly conjoined with the universal short-range repulsive Ziegler-Biersack-Littmark potential to account for simulations of high-energy collisions. By investigating the evolution of point defects, defect cluster distribution, and dislocation analysis, it was observed that the irradiated nanostructured Cu specimens survived with comparatively lower defects at the end of cascade simulations. GB serves as the effective radiation sink junctions for the generated Frenkel pair defects. Secondly, the population of point defects increases with the increase in PKA energy magnitude and the annihilation rate. Therefore, polycrystalline irradiated Cu specimens can be favoured for potential radiation immune candidate in the next-generation nuclear reactor structural materials.

Automated summary

This study investigates the radiation damage in irradiated copper specimens using molecular dynamics simulations. The results show that nanostructured copper specimens have fewer defects and grain boundaries serve as effective radiation sinks.