|About this Abstract
||Materials Science & Technology 2020
||High Entropy Materials: Concentrated Solid Solution, Intermetallics, Ceramics, Functional Materials and Beyond
||Controllable Phase Heterogeneity in High Entropy Oxides
||Alexander D. Dupuy, Julie M Schoenung
|On-Site Speaker (Planned)
||Alexander D. Dupuy
A unique characteristic of high entropy oxide (HEO) materials is their reversible entropy-driven phase transformation between the single phase and multiphase states. This feature presents an opportunity to produce oxide materials with highly controlled phase states. Here we explore the manifestation, behavior, and consequences of this phase transformation in (CoCuMgNiZn)O. First, we show that solid state synthesis and sintering can be used to consolidate fully dense HEO ceramics with grain sizes spanning several orders of magnitude. We demonstrate that the phase heterogeneity can be controlled through heat treatment, while the as-consolidated grain size significantly influences the secondary phase evolution and morphology. Then, we discuss our efforts to characterize the secondary phases using atom probe tomography (APT), x-ray absorption spectroscopy (XAS), x-ray diffraction (XRD), and electron microscopy. Finally, we explore the ramifications that the controlled phase state has on the electrical and mechanical properties.