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Title: Simulations of in situ x-ray diffraction from uniaxially compressed highly textured polycrystalline targets

A growing number of shock compression experiments, especially those involving laser compression, are taking advantage of in situ x-ray diffraction as a tool to interrogate structure and microstructure evolution. Although these experiments are becoming increasingly sophisticated, there has been little work on exploiting the textured nature of polycrystalline targets to gain information on sample response. Here, we describe how to generate simulated x-ray diffraction patterns from materials with an arbitrary texture function subject to a general deformation gradient. We will present simulations of Debye-Scherrer x-ray diffraction from highly textured polycrystalline targets that have been subjected to uniaxial compression, as may occur under planar shock conditions. In particular, we study samples with a fibre texture, and find that the azimuthal dependence of the diffraction patterns contains information that, in principle, affords discrimination between a number of similar shock-deformation mechanisms. For certain cases, we compare our method with results obtained by taking the Fourier transform of the atomic positions calculated by classical molecular dynamics simulations. Illustrative results are presented for the shock-induced α–ϵ phase transition in iron, the α–ω transition in titanium and deformation due to twinning in tantalum that is initially preferentially textured along [001] and [011]. The simulations are relevantmore » to experiments that can now be performed using 4th generation light sources, where single-shot x-ray diffraction patterns from crystals compressed via laser-ablation can be obtained on timescales shorter than a phonon period.« less
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Physics, Clarendon Laboratory University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)
  2. Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)
  3. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22499254
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABLATION; COMPARATIVE EVALUATIONS; DEFORMATION; FOURIER TRANSFORMATION; IRON; LASER RADIATION; LIGHT SOURCES; MICROSTRUCTURE; MOLECULAR DYNAMICS METHOD; PHASE TRANSFORMATIONS; PHONONS; POLYCRYSTALS; SIMULATION; TANTALUM; TARGETS; TEXTURE; TITANIUM; TWINNING; X-RAY DIFFRACTION