High entropy alloys: A review of preparation techniques, properties and industry applications

High entropy alloys (HEAs) represent a novel class of multi-component materials characterized by a paradigm-shifting design that incorporates five or more principal elements in nearly equal proportions. This configuration results in high configurational entropy and the formation of solid solutions . This review succinctly outlines the theoretical foundations of HEAs, including the entropy of the alloy and its thermodynamic stability, following a discussion of design principles and first-principles calculations that are crucial for alloy optimization, we provide a comprehensive review of various preparation techniques, such as mechanical alloying, magnetron sputtering , vacuum smelting, and additive manufacturing , emphasizing their influence on the properties of HEAs. The paper meticulously examines the core effects of these alloys—high entropy, lattice distortion, slow diffusion, and cocktail effects—which contribute to their unique attributes. Additionally, the review explores the promising applications of HEAs in sectors such as aerospace, energy, chemical industries, hydrogen storage, and ocean engineering, highlighting the increasing demand for advanced materials . Looking ahead, we propose future research directions that focus on the interplay between multi-scale structures and properties, interdisciplinary preparation technologies, and sustainable alloy recovery and reuse strategies. This review aims to provide both theoretical insights and practical guidelines for the rapidly evolving field of high entropy alloys.