title: Shock waves in polycrystalline iron.
abstract: The propagation of shock waves through polycrystalline iron is explored by large-scale atomistic simulations. For large enough shock strengths the passage of the wave causes the body-centered-cubic phase to transform into a close-packed phase with most structure being isotropic hexagonal-close-packed (hcp) and, depending on shock strength and grain orientation, some fraction of face-centered-cubic (fcc) structure. The simulated shock Hugoniot is compared to experiments. By calculating the extended x-ray absorption fine structure (EXAFS) directly from the atomic configurations, a comparison to experimental EXAFS measurements of nanosecond-laser shocks shows that the experimental data is consistent with such a phase transformation. However, the atomistically simulated EXAFS spectra also show that an experimental distinction between the hcp or fcc phase is not possible based on the spectra alone.
authors.affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. kkadau@lanl.gov
authors.forename: Kai
authors.initials: K
authors.lastname: Kadau
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Germann
authors.forename: Peter S
authors.initials: PS
authors.lastname: Lomdahl
authors.forename: Robert C
authors.initials: RC
authors.lastname: Albers
authors.forename: Justin S
authors.initials: JS
authors.lastname: Wark
authors.forename: Andrew
authors.initials: A
authors.lastname: Higginbotham
authors.forename: Brad Lee
authors.initials: BL
authors.lastname: Holian