High Entropy Materials—The First Twenty Years

The high-entropy concept has been defined, studied, questioned and expanded over the past twenty years. First claimed as a major new direction of materials science, it is fitting to re-evaluate the topic at this notable anniversary. The field has grown significantly beyond the initially conceived single-phase metallic solid solutions to embrace single and multi-phase materials for both functional and structural applications. As a further expansion, the high-entropy concept has been applied to metallic, semi-metal and ceramic materials. This talk opens with a brief introduction to the history of HEAs, including predecessor efforts prior to the dual landmark publications in 2004, and a quick description of its defining features. Commercially used functional and structural medium- and high-entropy materials will be highlighted, with the intent of illustrating promising directions for new HEA applications. This talk closes by describing an unanticipated role of HEAs – as a major motivation to develop and deploy autonomous research and development methods to a broader range of materials. The specific challenges that HEAs bring to autonomous research and development will be introduced and discussed.