Exploring high entropy alloys: A review on thermodynamic design and computational modeling strategies for advanced materials applications

In the quest for materials that can withstand the rigors of modern engineering applications, high-entropy alloys (HEAs) have emerged as a frontier in material science owing to their unprecedented combination of properties. This review focuses on intricate thermodynamic and computational modeling to guide the design and optimization of HEAs. By dissecting the foundational "four core effects" intrinsic to HEAs—high entropy, sluggish diffusion, severe lattice distortion, and cocktail effect—we illuminate the path towards predictable and tailored material properties. Central to the present discourse is the application of valence electron concentration (VEC) and cutting-edge strategies, including the CALculation of PHAse Diagrams (CALPHAD) method, first-principles approach, and machine-learning algorithms, which collectively empower the prediction and understanding of HEA behavior. Through a novel case study of a septenary equiatomic Ni-Al-Co-Cr-Cu-Mn-Ti HEA, this analysis demonstrates the utility of these computational tools in unveiling the alloy's phase stability and microstructural evolution, reinforcing the synergy between theoretical predictions and experimental validation. Furthermore, the review explores the burgeoning applications of HEAs across diverse sectors, such as aerospace, automotive, energy, and biomedical engineering, highlighting their transformative potential. Despite these advancements, challenges such as empirical design limitations, processing complexities, and the need for comprehensive databases are acknowledged, setting the stage for future exploration. This review not only charts a course for the rational design of HEAs, but also envisages their role in advancing material science towards novel applications, urging a concerted effort to overcome existing hurdles and explore uncharted territories in HEA research.