Stress‐Assisted Corrosion Behavior of Al 0.1 CrCoFeNi High‐Entropy Alloy and Alloy 718 in a NaCl–Na ₂ SO ₄ Molten Salt

Structural performance in molten salt environments is important for materials used in high‐temperature aerothermal components at marine sites and for novel energy generation such as thermal, solar, and next‐generation nuclear power systems. A better understanding of damage processes in these materials in molten salts is critical for accurate predictions of their life under targeted operative conditions. The present research was aimed at understanding corrosion mechanisms for a high‐entropy alloy (HEA) Al 0.1 CrCoFeNi in comparison with Alloy 718 in molten NaCl–Na 2 SO 4 under biaxial loading conditions. Thickness of the dealloyed zone at each tested specimen surface was measured as a function of time at 1023 K under a biaxial tensile stress imposed using a novel molten salt/disc bend configuration. While the HEA was observed to be slightly more resistant to dealloying in the absence of loading, Alloy 718 exhibited less dealloying under stress. Dealloying depth as a function of time data further indicated that both alloys transition from a diffusion‐limited dealloying to much faster mass transport dealloying with the application of biaxial tension. This finding was consistent with SEM observations of oxide scales on unloaded samples compared to the absence of scales on samples that were loaded.