Ultrafast X-ray Diffraction Study of a Shock-Compressed Iron Meteorite above 100 GPa

• Published in: Minerals (Basel) Vol. 11; no. 6; p. 567
• Main Authors: Tecklenburg, Sabrina, Colina-Ruiz, Roberto, Hok, Sovanndara, Bolme, Cynthia, Galtier, Eric, Granados, Eduardo, Hashim, Akel, Lee, Hae Ja, Merkel, Sébastien, Morrow, Benjamin, Nagler, Bob, Ramos, Kyle, Rittman, Dylan, Walroth, Richard, Mao, Wendy L., Gleason, Arianna E.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2021; MDPI
• Subjects: Compression; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Crystal structure; Crystallites; Crystals; Elasticity; Experiments; Ferrous alloys; Geophysics; Grain boundaries; Iron; iron meteorite; Iron meteorites; Kamacite; Kinetics; laser shock compression; Lasers; Material properties; MATERIALS SCIENCE; Mechanics; Mechanics of materials; Meteors & meteorites; Nickel; Phase transitions; Physics; Shock; Temporal resolution; ultrafast X-ray diffraction; X rays; X-ray diffraction; iron meteorite; laser shock compression; ultrafast X-ray diffraction
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min11060567

Natural kamacite samples (Fe92.5Ni7.5) from a fragment of the Gibeon meteorite were studied as a proxy material for terrestrial cores to examine phase transition kinetics under shock compression for a range of different pressures up to 140 GPa. In situ time-resolved X-ray diffraction (XRD) data were collected of a body-centered cubic (bcc) kamacite section that transforms to the high-pressure hexagonal close-packed (hcp) phase with sub-nanosecond temporal resolution. The coarse-grained crystal of kamacite rapidly transformed to highly oriented crystallites of the hcp phase at maximum compression. The hcp phase persisted for as long as 9.5 ns following shock release. Comparing the c/a ratio with previous static and dynamic work on Fe and Fe-rich Fe-Ni alloys, it was found that some shots exhibit a larger than ideal c/a ratio, up to nearly 1.65. This work represents the first time-resolved laser shock compression structural study of a natural iron meteorite, relevant for understanding the dynamic material properties of metallic planetary bodies during impact events and Earth’s core elasticity.