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Work hardening and inherent plastic instability of nanocrystalline metals
Author(s) -
Kurmanaeva L.,
Ivanisenko Yu.,
Markmann J.,
Yang K.,
Fecht H.J.,
Weissmüller J.
Publication year - 2010
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201004095
Subject(s) - nanocrystalline material , materials science , brittleness , ductility (earth science) , strain hardening exponent , instability , hardening (computing) , work hardening , composite material , metallurgy , uniaxial tension , tension (geology) , strain rate , compression (physics) , ultimate tensile strength , microstructure , nanotechnology , mechanics , creep , physics , layer (electronics)
We report an investigation of the mechanical behaviour of nanocrystalline (nc) Pd and Pd 90 Au 10 with mean grain size around 14 nm. All specimens were brittle in tension and ductile in compression. We analyze the parameters that control a material's potential for ductility in tension, namely strain hardening exponent, n , and strain rate sensitivity, m . The results reveal low values, n ≈ m ≈ 0.05. This constitutive behavior is known to promote plastic instability and, hence, rapid fracture in tension. Therefore, our results suggest that a tendency for localized deformation is an inherent feature of nc materials. It appears that the limited ductility of nc materials in tension is not related to microstructural flaws, but is a consequence of the concomitant low values of n and m . (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)