Irradiation induced grain boundary Flow - A new creep mechanism at the nanoscale

Yinon Ashkenazy, Robert S. Averback

Research output: Contribution to journalArticle

Abstract

A new mechanism of irradiation enhanced creep is proposed for nanocrystalline materials. It derives from local relaxations within the grain boundaries as they absorb point defects produced by irradiation. The process is studied by inserting point defects into the grain boundaries and following the materials response by molecular dynamics. Calculated creep compliances are found in good agreement with those measured in dilute nanocrystalline Cu-W alloys [Tai, K.; Averback, R. S.; Bellon, P.; Ashkenazy Y. Scr. Mater.2011, 65, 163]. The simulations provide a direct link between irradiation induced creep in nanocrystalline materials with radiation-induced viscous flow in amorphous materials, suggesting that grain boundaries in these materials can be treated as an amorphous phase. We provide a simple analytic model based on this assumption that reproduces the main features of the observed creep rates, a linear dependence on stress, inverse dependence of grain size, a weak dependence on temperature, and a reasonable estimate of the absolute creep rate.

Original languageEnglish (US)
Pages (from-to)4084-4089
Number of pages6
JournalNano letters
Volume12
Issue number8
DOIs
StatePublished - Aug 8 2012

Keywords

  • amorphous metals
  • atomistic simulation
  • Irradiation induced creep
  • metallic glass
  • nanocrystalline materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

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