Polycrystalline iron under compression: Plasticity and phase transitions

Nina Gunkelmann, Eduardo M. Bringa, Keonwook Kang, Graeme J. Ackland, Carlos J. Ruestes, Herbert M. Urbassek

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Abstract

Iron undergoes a bcc to close-packed structural phase transition under pressure, at around 13 GPa, as shown by diamond anvil and shock experiments. Atomistic simulations have been able to provide insights into the transition, but without any plasticity occurring before the phase change, in single crystals, defective single crystals, or polycrystals. However, experiments in polycrystals do show clear evidence for plasticity. Here we study homogeneous uniaxial compression of polycrystalline Fe using several interatomic potentials: three embedded-atom-model potentials and one modified embedded-atom-model potential. We analyze grain-boundary rotation and dislocation activity, and find that the amount of dislocation activity as a function of strain depends greatly on the potential used. This variation can be explained in terms of the dislocation properties, calculated in this work for each of these potentials.

Original languageEnglish
Article number144111
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number14
DOIs
Publication statusPublished - 2012 Oct 16

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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