Atomic-Scale Simulations Reveal the Influence of Ordered Phase Content on the High-Temperature Mechanical Behavior of AlCoCrFeMo0.05Ni2 High- Entropy Alloy

ZF Zhang and B Xu and QL Ye, JOM, 77, 9162-9174 (2025).

DOI: 10.1007/s11837-025-07747-8

Annealing AlCoCrFeMo0.05Ni2 high-entropy alloy at 973 K leads to the formation of ordered phases, which significantly influences its high- temperature (973 K) plasticity. The underlying microstructural mechanisms remain poorly understood. This work provides an in-depth investigation into the correlation between ordered phase content and high-temperature tensile behavior, employing atomic-scale simulations. The study reveals that the ordered phase content demonstrably influences deformation behavior. At low concentrations (below 20%), deformation is dominated by simple stacking fault evolution. This restricts both plasticity and stress relief. Conversely, intermediate concentrations (around 50%) exhibit pronounced dynamically balanced stacking fault evolution. This evolution is characterized by cyclic internal stress evolution coupled with non-monotonic structural transformations. This evolution can facilitate dynamic stress accommodation, thereby promoting uniform deformation. At high concentrations (above 80%), stacking fault evolution provides an effective stress relief mechanism. This highlights the contribution of the ordered phase to plasticity. This stress relief mechanism of the ordered phase and its dynamic interaction with the disordered phase are critical for enhancing high-temperature ductility in the alloy.

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