Interaction between an edge dislocation and faceted voids in body-centered cubic Fe

Irradiation defects cause mechanical property degradation in reactor materials. The relationship between dislocations and defects in these materials is of particular importance to mechanical strength. In the current study, we investigate the interaction between an edge dislocation and different faceted void ge-ometrical combinations using molecular dynamics to clarify the cutting mechanism and void effects on irradiation hardening in pure iron. We elucidate the difference in obstacle strength and the cutting pro-cess between spherical voids and faceted voids, especially for different faceted void configuration types. The highest critical shear stress in the type-a faceted void configuration is observed from the lower to upper void region, whereas that in the type-b faceted void configuration is observed at the void center, with the critical shear stress decreasing with increasing and decreasing normalized distance from the void center (dnorm). As for the type-c faceted void configuration, the highest critical shear stress is ob-served at the lower region of the void. The difference in the cutting process is due to the faceted plane; the highest critical shear stress is observed at the region where the dislocation cuts the {1101 plane of the faceted void. The {1101 plane is the close packed plane of the body center cubic structure, and there-fore the largest amount of energy is required to cut the atomic binding and slip the next equivalent {1101 plane compared to other planes. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Irradiation defects in reactor materials lead to degradation of mechanical properties. This study focuses on the relationship between dislocations and defects, specifically investigating the interaction between an edge dislocation and different faceted void geometrical combinations in pure iron. The results reveal the differences in obstacle strength and cutting process between spherical voids and faceted voids, with the highest critical shear stress observed at different regions depending on the faceted void configuration type. The cutting process is influenced by the faceted plane, with the {1101 plane of the faceted void requiring the highest amount of energy to cut the atomic binding.