Thermodynamic, phase diagram, and high-entropy alloys system: basic concepts

The evolution of alloy-based materials, transitioning from simple binary alloy systems to more intricate compositions, has played a pivotal role in facilitating the advancement of innovative technologies and, in turn, driving social progress. This transformative journey has been accompanied by a significant enhancement in humanity’s capacity to create novel materials. High-entropy alloys (HEAs) have emerged as a recent and noteworthy class of materials due to their novel concept and remarkable properties. These alloys exhibit exceptional mechanical characteristics, boasting impressive strength, resistance to corrosion, and thermostability, surpassing the capabilities of traditional alloys. Consequently, HEAs have given rise to an entirely new realm of advanced materials, ushering in a distinct field of study. This chapter delves into essential concepts, encompassing the composition and entropy-based definition of HEAs, distinguishing them from outdated alloy types, highlighting their unique attributes, exploring phase diagram classification, addressing four core effects, and presenting models and criteria for HEAs. Furthermore, we shed light on the vast uncharted territory within this field and provide insights into the promising avenues that future trends and prospects may bring to fruition. © 2024 Elsevier Inc. All rights are reserved including those for text and data mining AI training and similar technologies.