Review on the transition from conventional to multi-component-based nano-high-entropy alloys—NHEAs

This paper reviews on advancement within the areas of alloy design from typical to multi-component alloys, known as ‘high-entropy alloys’—HEAs [supported with ≥ five elements]. These multi-component alloys belong to a promising category, and these designs are based on near equiatomic or non-equiatomic molar ratio. They show characteristics like cocktail effects, severe lattice distortion and sluggish diffusion, which enhance the mechanical and thermal properties in contrast with Al-, Mg-, Sc-, Ti- and Ni-based alloy design. The advancement in ‘HEA’ has revived the approach of alloy design and shows the ways to generate a wide number of enriched compositions with a variety of blending, with promising properties for a variety of applications in structural, medical and defense fields. We also have provided information in this paper on fabricating routes, criteria, models for HEAs and list of existing lightweight HEAs.