Fundamentals of High Entropy Alloys

High-entropy alloys (HEAs) are a relatively new class of materials that push the boundaries of traditional alloy design strategies and provide vast compositional space. This multifaceted field combines thermodynamics, metallurgy, phase stability, crystallography, and mechanical behavior to fulfill the need to achieve unique synergies caused by high compositional complexity. Yet, even in their nascent stages, the definition, and characteristics of HEAs have not been without conflict and debate, adding an additional layer of complexity to this intriguing field. This chapter discusses the intricate aspects of HEAs such as thermodynamics, the four core effects, alloy design strategies, and rebutting misconceptions related to HEAs.