|About this Abstract
||Materials Science & Technology 2020
||High Entropy Materials: Concentrated Solid Solution, Intermetallics, Ceramics, Functional Materials and Beyond
||Bond-order Bond Energy Model for Concentrated Solid Solutions
||Szu-Chia Chien, Christian Oberdorfer, Wolfgang Windl
|On-Site Speaker (Planned)
We introduce a novel way to parameterize random-alloy energies in the form of a bond-order bond energy model. There, a bond order function models the transition between competing phases or bond types and switches their respective bond energies on and off. We first demonstrate this on the example of the Ni-Cr-Mo alloy system and then move to Cantor-type concentrated solid solution systems. We show that the bond-order bond energy model can predict phase diagrams with excellent accuracy in a simple fashion. We also show that bond-energies define quantitative, composition-dependent chemical potentials in a natural way, allowing to efficiently calculate configuration-optimized alloy vacancy formation energies. As proposed by the concept of the extended Gibbs adsorption isotherm, alloying decreases formation energies, where values smaller than zero indicate thermodynamic instability of the underlying crystal. With that, the bond-order bond energy model provides an intuitive holistic picture that unites defect and phase stability.