Abstract:

High-entropy materials represented by high-entropy alloys have been the focus of materials science research in the past 15 years. In contrast to rapid and fruitful progress in high-entropy alloys, studies on high-entropy ceramics which are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements are still in the infant stage. To date, considerable progress has been made in exploring new high-entropy ceramic systems and in their composition-structure-performance relationship. Distinct from metals, the diversity in crystal structure and electronic structure of ceramics provides huge space for property tuning through band structure engineering and phonon engineering.  Aside from strengthening, hardening, and low thermal conductivity that have already been found in high-entropy alloys, new properties like colossal dielectric constant, superionic conductivity, severe anisotropic thermal expansion coefficient, strong electromagnetic wave absorption, etc., have been discovered in high-entropy ceramics. As a response to the rapid development in this nascent field, this seminar summarizes and reviews the connotation, new system, application, and development direction of high entropy ceramics.