About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Significance of Free Energy Contributions beyond Configurational Entropy in Superalloys and High Entropy Alloys |
Author(s) |
Naga Sri Harsha Gunda, Maryam Ghazisaeidi |
On-Site Speaker (Planned) |
Naga Sri Harsha Gunda |
Abstract Scope |
Configurational entropy plays a vital role in stabilizing high entropy alloys and multi-component superalloys with a superior mechanical response. However, alloy design requires accurate determination of free energies in competing disordered systems such as fcc- and hcp-based solid solutions. The derivation of entropies beyond configurational entropy is not well established for systems with complex compositions. We present a methodology using first-principles calculations to derive the necessary contributions to the free energy for accurately determining relative stability between phases at finite temperatures. We show the significance of calculating entropy from vibrations, electronic excitations, and magnetism to determine phase transformation temperatures in the NiCoCr ternary derivative of cantor alloy. Here the hcp disordered phase is expected to be stable at lower temperatures. Furthermore, we will demonstrate the competing phase stability in fcc Ni-based superalloys where the localized phase transformation phenomenon stabilized the hcp phase. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, High-Entropy Alloys, Phase Transformations |