title: Direct observation of the alpha-epsilon transition in shock-compressed iron via nanosecond x-ray diffraction.
abstract: In situ x-ray diffraction studies of iron under shock conditions confirm unambiguously a phase change from the bcc (alpha) to hcp (epsilon) structure. Previous identification of this transition in shock-loaded iron has been inferred from the correlation between shock-wave-profile analyses and static high-pressure x-ray measurements. This correlation is intrinsically limited because dynamic loading can markedly affect the structural modifications of solids. The in situ measurements are consistent with a uniaxial collapse along the [001] direction and shuffling of alternate (110) planes of atoms, and are in good agreement with large-scale nonequilibrium molecular dynamics simulations.
authors.affiliation: Lawrence Livermore National Laboratory, California 94550, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Kalantar
authors.forename: J F
authors.initials: JF
authors.lastname: Belak
authors.forename: G W
authors.initials: GW
authors.lastname: Collins
authors.forename: J D
authors.initials: JD
authors.lastname: Colvin
authors.forename: H M
authors.initials: HM
authors.lastname: Davies
authors.forename: J H
authors.initials: JH
authors.lastname: Eggert
authors.forename: T C
authors.initials: TC
authors.lastname: Germann
authors.forename: J
authors.initials: J
authors.lastname: Hawreliak
authors.forename: B L
authors.initials: BL
authors.lastname: Holian
authors.forename: K
authors.initials: K
authors.lastname: Kadau
authors.forename: P S
authors.initials: PS
authors.lastname: Lomdahl
authors.forename: H E
authors.initials: HE
authors.lastname: Lorenzana
authors.forename: M A
authors.initials: MA
authors.lastname: Meyers
authors.forename: K
authors.initials: K
authors.lastname: Rosolankova
authors.forename: M S
authors.initials: MS
authors.lastname: Schneider
authors.forename: J
authors.initials: J
authors.lastname: Sheppard
authors.forename: J S
authors.initials: JS
authors.lastname: Stölken
authors.forename: J S
authors.initials: JS
authors.lastname: Wark