Invited viewpoint: on the term “High Entropy Alloys”

”Tis but thy name that is my enemy” Shakespeare, Romeo and Juliet. The term “High Entropy Alloys” (HEA) has become very popular in the alloy development community in recent years. The term is specific to a subset of alloy composition space in which a solid solution is stabilized by a high configurational entropy due to a large number of equimolar components. Numerous research papers contain the term, yet on examination much of the work is not in fact on alloys stabilized by the entropy component of the Gibbs energy. This paper discusses the reasons why the term should be used only for alloys in which entropy is the dominant thermodynamic parameter, and more appropriate terms such as multi-principal element alloys should be used for the vast majority of research papers on this topic.