Optical full-field strain measurement within a diamond anvil cell

Robin Fréville; Nicolas Bruzy; Agnès Dewaele

doi:10.1063/5.0176231

Optical full-field strain measurement within a diamond anvil cell

Rev Sci Instrum. 2023 Dec 1;94(12):123905. doi: 10.1063/5.0176231.

Authors

Robin Fréville¹, Nicolas Bruzy¹, Agnès Dewaele¹

Affiliation

¹ CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, F-91680 Bruyères-le-Châtel, France.

PMID: 38117198
DOI: 10.1063/5.0176231

Abstract

Digital image correlation computations are run on optical images of iron samples within a diamond anvil cell to obtain in-plane strain components at the surface of the sample up to 17 GPa. The α-Fe → ε-Fe transition onset pressure and phase coexistence pressure domain can be identified from the evolution of the surface average of strain components. Strain fields exhibit localizations for both direct and reverse transition; they coincide with the approximate boundary locations of reversion variants inside the microstructure of a single crystal sample. The so-called DICDAC (Digital Image Correlation within a Diamond Anvil Cell) setup is then a suitable tool for the investigation of phase transformations strains under pressure. In addition, specific volumes that are deduced from strain out of the transition pressure domains agree within ΔV/V = 0.4% with the equation of state data from the literature.