Journal
ACTA MATERIALIA
Volume 56, Issue 2, Pages 282-291Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2007.09.031
Keywords
nanostructured metals; shear banding; geometric softening; grain rotation
Ask authors/readers for more resources
Previous experimental observations on some nanostructured metals have indicated a transition from homogeneous to non-homogeneous plastic deformation with a reduction in grain size [Jia D, Ramesh KT, Ma E. Acta Mater 2003;51:349]. We present a model that predicts the development of shear bands in such materials under quasi-static loading rates. Motivated by microscopic observations, a grain rotation based geometric softening mechanism is implemented as an internal variable within a viscoplastic constitutive setting. The model predicts the occurrence of the shear bands at small grain sizes, whereas at larger grain sizes it predicts homogeneous plastic flow. The model also predicts the phenomenon of shear band broadening with strain, which is experimentally observed, and attributes this to the '' rotational diffusion '' mechanism along with the restoration of material hardening within the band following the saturation of grain reorientation. Finally, we provide a localization index that can be used to classify nanostructured metals in terms of the susceptibilitv to this shear band mechanism. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available