X-ray diffraction study of phase transformation dynamics of Fe and Fe-Si alloys along the shock Hugoniot using an x-ray free electron laser

A. Krygier (1, 2) , M. Harmand (2) , B. Albertazzi (3) , E. Mcbride , K. Miyanishi , Daniele Antonangeli (2) , Y. Inubushi , R. Kodama , M. Koenig (3) , T. Matsuoka , G. Mogni (2) , F. Pietrucci (2) , A. Saitta (2) , T. Togashi , Y. Umeda , T. Vinci (3) , M. Yabashi , T. Yabuuchi , G. Fiquet (2) , N. Ozaki

1 LLNL - Lawrence Livermore National Laboratory
2 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
3 LULI - Laboratoire pour l'utilisation des lasers intenses

The x-ray free electron laser (XFEL) enables probing highly compressed material response at the subnanosecond timescale. We exploit the ultrafast XFEL pulse to combine reflection x-ray diffraction and laserdriven shock compression to perform a study of phase transformation and stability in iron and Fe-Si alloys. Our approach enables us to observe that solid-solid phase transformations occur in iron and Fe-Si8.5wt% in ≤130 ps at ∼130 GPa; no transformation is observed in Fe-Si16wt% up to 110 GPa. Density Functional Theory calculations predict similar phase relations.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

A. Krygier, M. Harmand, B. Albertazzi, E. Mcbride, K. Miyanishi, et al.. X-ray diffraction study of phase transformation dynamics of Fe and Fe-Si alloys along the shock Hugoniot using an x-ray free electron laser. Physical Review B, 2022, 105 (22), pp.L220102. ⟨10.1103/PhysRevB.105.L220102⟩. ⟨hal-03827639⟩