**About this Abstract** |

**Meeting** |
**2017 TMS Annual Meeting & Exhibition
** |

**Symposium
** |
**Computational Thermodynamics and Kinetics
** |

**Presentation Title** |
Single and Poly- Crystal Elastic Constants of Nickel and Ni-H_{x} Alloys at Finite Temperature from Experiments and First Principles Calculations |

**Author(s)** |
Guillaume Hachet, Arnaud Metsue, Abdelali Oudriss, Marc Huger, Xavier Feaugas |

**On-Site Speaker (Planned)** |
Guillaume Hachet |

**Abstract Scope** |
The effects of H on the mechanical properties of metals have to be quantified for a better understanding of hydrogen embrittlement (HE). We have conducted experimental and numerical investigations on the elastic constants of nickel (Ni) and nickel-hydrogen alloys (Ni-H_{x}) since too few data can be found in the literature. Uniaxial tensile tests and ultrasonic measurements have been carried out on (001), (011) and (111) oriented single crystals Ni and Ni-H_{x} structure in the 300-1000K temperature range. Also, the components of the elastic constant tensor of these materials have been calculated from first principles. We have calculated the isothermal and adiabatic C_{ijkl} up to the melting temperature from the computation of the Helmholtz free energy expressed as a sum of static, vibration and electronic excitations contributions. Finally, we have used homogenisation techniques to determine the elastic constants of polycrystals, which have been compared with additional experiments on these materials. |

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