Dominating deformation mechanisms in ultrafine-grained chromium across length scales and temperatures

Reinhard Fritz, David Wimler, Alexander Leitner, Verena Maier-Kiener, Daniel Kiener

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22 Citations (Scopus)


The microstructure influence on the thermally activated deformation behaviour of chromium is investigated for a more fundamental understanding of the deformation mechanisms contributing to plasticity in bcc metals. Therefore, scale-bridging experiments at variable temperatures and varying strain-rates are performed, encompassing macroscopic compression tests in direct correlation to local in-situ SEM micro-compression experiments on taper-free pillars and advanced nanoindentation testing. For the first time, it is demonstrated that, independent of stress state, sample volume and surface fraction, a distinct temperature-dependent transition of the dominating deformation mechanism occurs. While at low temperatures the lattice resistance dominates, exceeding a critical temperature the dislocation interaction with grain boundaries becomes the rate limiting step. Finally, based on the vastly different fractions of grain boundaries in the tested sample volumes, a comprehensive model on the deformation of bcc metals, in particular at small scales or for confined volumes is derived.
Original languageEnglish
Pages (from-to)176-187
Number of pages12
JournalActa materialia
Issue numberNovember
Early online date22 Aug 2017
Publication statusPublished - 1 Nov 2017


  • Elevated temperature testing
  • In-situ
  • Scale-bridging experiments
  • Strain-rate sensitivity
  • Thermally activated processes
  • Ultrafine-grained materials

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