| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Bond-order Bond Energy Model for Alloys |
| Author(s) |
Wolfgang Windl, Christian Oberdorfer, Maryam Ghazisaeidi |
| On-Site Speaker (Planned) |
Wolfgang Windl |
| Abstract Scope |
We introduce a novel way to parameterize alloy energies in the form of a bond-order bond energy model. There, a bond order function models the transition between competing phases and switches their respective bond energies on and off. We demonstrate this on the example of the Ni-Cr-Mo alloy system, which has both face- and body-centered cubic phases. 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. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |