Abstract: Voids are critical irradiation-induced defects that significantly influence the concurrent enhancement of strength and toughness of advanced structural alloys such as high-entropy alloys (HEAs) in nuclear plants. However, direct experimental characterization of dislocation-void interactions in HEAs remains inherently challenging due to spatial and temporal resolution limitations of the in situ transmission electron microscope. To bridge this gap, we performed molecular dynamics simulations to unravel the atomistic mechanisms underlying dislocation-void interactions in NiCoCr and FeNiCoCr HEAs under shearing loading. We systematically investigated the interaction dynamics as functions of void size, temperature, and dislocation character (edge vs. screw), and provided a quantitative explanation in terms of interaction energy landscapes. Building on these simulations, we propose a new theoretical framework that integrates an irradiation hardening model with dislocation-void interaction kinetics. The predicted hardness increment is close to that from experiments. Notably, this framework incorporates two previously overlooked factors: void cutting planes and the number of dislocation-cutting events. Our findings reveal distinctive interaction pathways and energetics unique to HEAs, offering mechanistic insight into how voids modulate plasticity at the atomic scale. These results expand our fundamental understanding of irradiation-induced hardening and provide a basis for tailoring the mechanical performance of HEAs in extreme environments.

Key words: High-entropy alloys, Molecular dynamics simulations, Dislocation, Void, Interaction