Origin of radiation damage variability in different phases of Al-Cr-Fe-Ni-V high-entropy alloy with heterogeneous microstructures

This study unravels the origin of divergent irradiation responses in Al0.5Cr0.9FeNi2.5V0.2 high-entropy alloy, which features characteristic Cr-rich precipitates and coherent spinodal L12 nanostructure within matrix. We demonstrate that the Cr-rich precipitates, with its lower mixing entropy and higher vacancy mobility, facilitates the nucleation and growth of large helium bubbles. Simultaneously, semi-coherent interfaces serve as preferential sinks, further promoting bubble coalescence and dislocation loop accumulation. In contrast, the L12 nanostructure resists irradiation-induced disordering through order–disorder transitions and anti-phase boundaries, thus effectively suppressing helium bubble growth and pinning dislocation loops. These findings offer a mechanistic guideline for designing alloys for extreme environments.