Kinetic prediction of competitive phase formation in high-entropy alloys under varying cooling rates

Анотація

This study presents a kinetic approach for predicting the phase constitution of multicomponent high-entropy alloys processed under non-equilibrium conditions. Unlike conventional thermodynamic, atomic-size, and electronic parameters that neglect the time-dependent nature of solidification, the proposed approach evaluates the critical cooling rate required to suppress the nucleation of competing stable and metastable phases. This allows phase stability to be assessed according to the actual time available for nucleation rather than equilibrium considerations alone.

The key feature of the model is a structure-dependent viscosity parameter that captures the packing efficiency of different crystal lattices and influences atomic mobility near the solidification front. Incorporating this parameter makes it possible to distinguish between phases that are thermodynamically similar but differ in kinetic accessibility. The model is evaluated using 30 multicomponent alloys processed under near-equilibrium casting and rapid quenching. The results show that the phase exhibiting the highest kinetic stability becomes dominant, enabling stabilization of metastable states that are inaccessible under slow cooling. The proposed kinetic approach successfully explains the formation of single-phase solid solutions, ordered structures, and complex multiphase microstructures in cases where static parameters produce ambiguous or incorrect predictions.