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

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

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

22 Zitate (Scopus)

Abstract

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.
OriginalspracheEnglisch
Seiten (von - bis)176-187
Seitenumfang12
FachzeitschriftActa materialia
Jahrgang140.2017
AusgabenummerNovember
Frühes Online-Datum22 Aug. 2017
DOIs
PublikationsstatusVeröffentlicht - 1 Nov. 2017

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