γ-surface informed phase-field modeling on structures and properties of defects in FeCoNiMnAl alloys

D Qiu and JW Wu, COMPUTATIONAL MATERIALS SCIENCE, 250, 113732 (2025).

DOI: 10.1016/j.commatsci.2025.113732

By adjusting the intrinsic stacking fault energy (ISFE) or the gamma- surface of face-centered cubic (fcc) high entropy alloys (HEAs), the resulting structures of interior defects, such as dislocations and grain boundaries (GBs) are able to manipulate the mechanical behaviors of HEAs. This work provides a complete framework on predicting the structures of both the core configuration of a single dislocation and the geometrically necessary dislocation (GND) networks within GBs. The formation of Shockley partials during dislocation dissociation is quantitatively predicted, with the core width being recorded within the range of 3.27 to 4.16b (b is the magnitude of the Burgers vector of a full dislocation), depending on the ISFE of the FeCoNiMnAl alloys. The simulated equilibrium structure of GND networks within the low-angle GB is carefully compared with the calculation result of the classical Frank-Bilby equation, where the energy-based relaxation is absent. With the core structures being determined, the Peierls stresses of FeCoNiMnAl alloys with the same average chemical composition but different atomistic arrangements are calculated and proved to be sensitive to the value of ISFE. Finally, the relationship between the gamma-surface profile along the 112 direction and the GB energy is provided, allowing one to estimate qualitatively the GB energy by the energy integral within the characteristic range of the gamma-surface by atomistic simulations.

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