Local-concentration-based descriptor predicting the stacking fault energy of refractory high-entropy alloys

C Ma and W Gao, PHYSICAL REVIEW MATERIALS, 7, L110401 (2023).

DOI: 10.1103/PhysRevMaterials.7.L110401

Refractory high-entropy alloys (RHEAs) show the potential for high- temperature structural materials, but their brittleness and low ductility at room temperature prohibit the processing and further practical applications, which can be characterized by the generalized stacking fault energy (GSFE). However, the local chemical environment varies significantly across parallel GSF planes, resulting in a substantial fluctuation of GSFE values rather than a unique value, which manifests the local nature of GSFE. We proposed an effective descriptor based on the local concentration ratio near the GSF to quantitatively predict the local GSFE of RHEAs. We find that the role of a given element in determining GSFE strongly depends on its valence-electron number relative to other components and the contribution of its s and d electrons to its cohesive properties. Notably, the descriptor not only unifies the local nature of GSFE from simple alloys to RHEAs but also helps to quickly design RHEAs as the involved parameters are easily accessible.

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