High-entropy alloys have become an important topic to study in modern materials science due to extraordinary properties which are manipulatable by changing chemical composition and microstructure engineering. However, thermally induced martensitic phase transformation, as an important phenomenon in physical metallurgy, was rarely observed and reported in these materials. The current investigation is focused to address the main reasons to suppress martensitic transformation by thermodynamic calculations in high-entropy shape memory alloys and FCC-based high-entropy alloys. The results suggest that intrinsic characteristics of high-entropy alloys such as high mixing entropy and severe lattice distortion together with thermodynamic parameters have key roles for this behavior. Gibbs free energy of martensitic transformation increases by increasing the entropy of mixing which confirms significant parent phase stability in these alloys. In addition, a random distribution of atoms leads to formation of a disordered atomic structure in the alloys and therefore, high degree of disorder may suppress martensitic transformation by impeding the movement of atoms during the phase transition. Intrinsic inhomogeneity in high-entropy alloys may also be responsible for deviating from the ideal order phase. The present investigation is a step forward to a fundamental understanding of this class of engineering materials for the alloy designing and developing high-performance materials.
Hamed Shahmir (Fri,) studied this question.