| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond V
|
| Presentation Title |
Controlling Factors of Vacancy Formation Energies in FCC Concentrated Alloys from DFT Calculations |
| Author(s) |
Nathan Linton, Dilpuneet S. Aidhy |
| On-Site Speaker (Planned) |
Nathan Linton |
| Abstract Scope |
Due to chemical and lattice symmetries, pure metals have one vacancy formation energy (VFE) value. However, concentrated alloys that consist of multiple elements in large proportions randomly distributed on a crystal lattice have a range of VFEs due to diverse nearest neighbor (NN) environments. Using density functional theory (DFT) calculations, we expound on the previous NN chemistry correlation and show that atomic volume and electronegativity have a significant effect on the VFE. Specifically, larger atomic volume increases VFE. Also, charge gain due to higher electronegativity of a central atom increases VFEs. We find that such mechanisms can lead to very large VFE variations, at times over 1 eV. We perform the study in model FCC alloys including binary Ni-Cu, Cu-Au, Ag-Au, and ternary Ni-Cu-Au. The fundamental principles observed in binaries translate into ternaries, which would be helpful in the design and development of FCC concentrated alloys for high temperature applications. |