|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||High Entropy Alloys VI
||Phonon Broadening in High Entropy Alloys
||Fritz Körmann, Yuji Ikeda, Blazej Grabowski, Marcel H.F. Sluiter
|On-Site Speaker (Planned)
Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation high-temperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). In contrast to perfect crystals and ordered alloys, the inherently present mass and force constant fluctuations in multi-component random alloys (high entropy alloys) can induce significant phonon scattering and broadening. We employ ab initio calculations to systematically study the impact of force constant and mass fluctuations on phonon spectral functions of twelve body-centered cubic random alloys, from binaries up to five-component high entropy alloys, addressing the key question of how chemical complexity impacts phonons. We find that it is crucial to include both mass and force constant fluctuations. If one or the other is neglected, qualitatively wrong results can be obtained such as artificial phonon band gaps. We further analyze how thermodynamically integrated quantities are affected, specifically the vibrational entropy.
||Planned: Supplemental Proceedings volume