**About this Abstract** |

**Meeting** |
**2018 TMS Annual Meeting & Exhibition
** |

**Symposium
** |
**High Entropy Alloys VI
** |

**Presentation Title** |
First-principles Phonon Approach to High Entropy Alloys |

**Author(s)** |
Yi Wang, Shun-Li Shang, Zi-Kui Liu, Long-Qing Chen |

**On-Site Speaker (Planned)** |
Yi Wang |

**Abstract Scope** |
An advance is made to apply the first-principles phonon methods to the multi-component high entropy alloys (HEAs) to predict their major phase transitions and hence the associated entropy changes. Using the refractory V-Nb-Mo-Ta-W as the benchmark, ~100 phases are studied with the vibrational, the electronic, and the configurational contributions all accounted for. To obtain the Gibbs energy of each individual phase at a given finite temperature, the lattice contribution is accounted for using the phonon theory and the electronic contribution is accounted for based on the Mermin statistics. To obtain the Gibbs energy for disordered systems, the selected quasirandom structure is employed aided by ideal mixing entropy. Finally, the calculated Gibbs energies are sorted using Dantzig's simplex algorithm to determine the relative phase stabilities and hence phase decompositions among all the calculated phases. Phase separations/ordering are thermodynamically predicted both for the quinary and all the quaternary when lowering the temperature. |

**Proceedings Inclusion?** |
Planned: Supplemental Proceedings volume |