Unlike most conventional alloys that consist of a major principal element, the new class of high-entropy alloys (HEAs) comprise multiple principal elements in high concentrations. The original rationale for the name was that high configurational entropy of mixing was expected to promote formation of solid solutions by suppressing intermetallic compounds. As it turns out, this happens infrequently; multi-phase alloys tend to be more common. Therefore, a broader name for these alloys is compositionally complex alloys (CCAs). Together, HEAs and CCAs occupy a vast unexplored space near the centers of phase diagrams where there are many new materials waiting to be discovered with potentially superior properties. Furthermore, within this space, there are fascinating unanswered questions about how to quantify compositional complexity and its effects on basic structure-property relationships.
This symposium focuses on both fundamental and practical aspects of HEAs and CCAs and their governing structure-property relationships. We solicit papers that address these issues using experimental and/or theoretical approaches. Of special interest are new developments in alloy design targeting properties beyond those possible with conventional alloys, as well as unique aspects of HEAs/CCAs attributable to their chemical and structural complexity.