A constitutive model of nanocrystalline metals based on competing grain boundary and grain interior deformation mechanisms


Gürses E., El Sayed T.

MATERIALS LETTERS, vol.65, pp.3391-3395, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 65
  • Publication Date: 2011
  • Doi Number: 10.1016/j.matlet.2011.07.039
  • Journal Name: MATERIALS LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3391-3395
  • Keywords: Nanocrystalline materials, Diffusion, Grain boundaries, Simulation and modeling, SIZE DISTRIBUTION, FCC METALS, PRESSURE, STRENGTH, BEHAVIOR, DIFFUSION, DEPENDENCE, ASYMMETRY, ALLOY
  • Middle East Technical University Affiliated: No

Abstract

In this work, a viscoplastic constitutive model for nanocrystalline metals is presented. The model is based on competing grain boundary and grain interior deformation mechanisms. In particular, inelastic deformations caused by grain boundary diffusion, grain boundary sliding and dislocation activities are considered. Effects of pressure on the grain boundary diffusion and sliding mechanisms are taken into account. Furthermore, the influence of grain size distribution on macroscopic response is studied. The model is shown to capture the fundamental mechanical characteristics of nanocrystalline metals. These include grain size dependence of the strength, i.e., both the traditional and the inverse Hall-Fetch effects, the tension-compression asymmetry and the enhanced rate sensitivity. (C) 2011 Elsevier B.V. All rights reserved.