**About this Abstract** |

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

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

**Presentation Title** |
Configuration Entropy of High Entropy Alloys |

**Author(s)** |
Alice Hu, JW Yeh, PK Liaw, CH Hu, Ky Fung, PJ Yu |

**On-Site Speaker (Planned)** |
Alice Hu |

**Abstract Scope** |
Ideal gas entropy calculation is the classic example, while liquid and solid entropies are determined indirectly from experimental measured enthalpy and free energy values. However this research shows direct crystalline entropy calculation. Presented result not only applies on high entropy alloys (HEAs), but should be universal to all non-mono composition alloys. Configurational entropy is usually neglected in conventional alloys due to solute solid solution assumption, however both ab-initio simulated negative stacking fault and experimental observed abundant evidence show that this should not be ignored in HEAs. Conventional treatment on configurational entropy in HEAs makes no difference in FCC, HCP and BCC, but this work clearly indicates how much entropy difference among them. Clarifying entropy difference is very important on the phase prediction and diffusion calculation. This treatment is helpful for accurate thermodynamic prediction of Thermalcalc, Calphad…etc. software. Precise calculation is important for mechanism study and alloy design. |

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