Abstract

Ab-initio Density Functional Theory has been used to compute phonons for interstitial hydrogen in α-iron. In the harmonic approximation, these phonons yield Helmholtz’s free energy as a function of temperature, which can be used to obtain diffusion barriers from an Arrhenius plot. By comparing with the experimental database compiled by Kiuchi and McLellan, we show that the role of phonons is crucial to understand the diffusion of interstitial hydrogen at T > 300 K. The computed specific heat for Fe16H and Fe behaves quite differently due to the appearance of optical modes and could be used to calibrate the amount of interstitials in the iron matrix.

Details

Title
Hydrogen in α-iron: role of phonons in the diffusion of interstitials at high temperature
Author
de Andres, Pedro L 1   VIAFID ORCID Logo  ; Sanchez, Javier 2   VIAFID ORCID Logo  ; Ridruejo, Alvaro 3   VIAFID ORCID Logo 

1  Instituto de Ciencia de Materiales de Madrid-CSIC, Madrid, Spain 
2  Instituto de Ciencias de la Construcción Eduardo Torroja-CSIC, Madrid, Spain 
3  Departamento de Ciencia de Materiales, ETSI Caminos Canales y Puertos, Universidad Politécnica de Madrid, Madrid, Spain 
Pages
1-9
Publication year
2019
Publication date
Aug 2019
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41598-019-48490-w
ProQuest document ID
2276821798
Copyright
© 2019. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.