Since their discovery in 2004, high-entropy alloys (HEAs) have generated significant interest from the scientific community. Based on a multi-principal element design approach, HEAs are engineered to possess a unique random solid solution (RSS) crystalline structure, in which each of the constituent elements has an equal probability of occupying a given lattice site. Published literature reports that certain HEAs exhibit exceptional chemical, physical, mechanical and functional properties that are attributed to the presence of a RSS phase. Not surprisingly, research on HEAs has begun to expand at an accelerated rate. The scientific and engineering topics being studied include: experimentally measuring various properties in HEA systems, understanding the effect of the RSS on these properties, and developing methods for predicting the formation of RSS phases. Accordingly, the goal of this brief review is to introduce the field of HEAs, discuss their core concepts, highlight exceptional properties, and discuss current design aspects.
The authors would like to thank the US Army Research Office (W911NF-16-1-0269) and the Alexander von Humboldt Research Award for Senior Researchers for funding.
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