High Entropy Alloys: The Materials of Future

Abstract

High Entropy Alloys (HEAs) have recently attracted the researchers' attention as a new track in materials design. Research on HEAs has stimulated new ideas and inspired the exploration of the enormous composition space offered by multi-principal element alloys. HEAs can be simply described as alloying systems that are composed of multi-elements in equimolar or near equimolar ratio. Therefore, HEAs have unique properties which significantly differ from the traditional alloy systems. The current review article is concerned with the definition of HEAs, their development history, and their four core effects which make them different from the traditional alloys. Fabrication routes of HEAs with special emphasis on processing via casting technique are surveyed. The innovative microstructure of HEAs that lead to extraordinary mechanical properties is also discussed. Finally, the promising industrial applications and the future insights of these multi principal alloys are covered.

Predictive analytics of wear performance in high entropy alloy coatings through machine learning

“…High Entropy Alloys (HEAs) comprise five or more major elements with an equimolar or non-equimolar ratio (5-35 at%) and have gained prominence for their single-phase solid solution [1,2]. The advantages of the singlephase solid solution of multicomponent HEAs and its extraordinary structure, HEAs are considered to safeguard turbine blades, engine parts, cutting tools, and various other components.…”

Large Destabilization of (TiVNb)-Based Hydrides via (Al, Mo) Addition: Insights from Experiments and Data-Driven Models

“…11−14 Furthermore, the properties of HEAs can be related to four core effects (cocktail effect, high entropy, sluggish diffusion, and lattice distortion). 15 Consequently, there is now a push to rationally design HEAs for hydrogen storage that can maximize capacity while minimizing desorption enthalpy (and required desorption temperature). 8,16 A number of HEAs with a bcc structure possess outstanding volumetric hydrogen capacities, as reported for TiVZrNbHf, 9 TiVZrNbHf 0.5 17 TiZrNbHfTa, 18 and Ti 4 V 3 NbCr 2 .…”

“…Attempts have been made to predict the formation and stability of such phases by different empirical parameters and to obtain rational theoretical design rules with varying degrees of success. Examples include the lattice distortion (δ) caused by the mismatch between different atomic sizes of the constituents, the valence electron concentration (VEC), the mixing enthalpy/entropy, or the entropy-to-enthalpy ratio (Ω). − Furthermore, the properties of HEAs can be related to four core effects (cocktail effect, high entropy, sluggish diffusion, and lattice distortion) …”