Constitutive modeling of strain rate effects in nanocrystalline and ultrafine grained polycrystals

Gürses E., Tamer E. S.

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol.48, no.10, pp.1610-1616, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 48 Issue: 10
  • Publication Date: 2011
  • Doi Number: 10.1016/j.ijsolstr.2011.02.013
  • Journal Name: INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1610-1616
  • Keywords: Constitutive modeling, Rate dependence, Nanocrystals, Crystal plasticity, Grain size, RATE SENSITIVITY, MECHANICAL-BEHAVIOR, ACTIVATION VOLUME, TENSILE BEHAVIOR, DEFORMATION, METALS, TEMPERATURE, CU, MICROSTRUCTURE, NI
  • Middle East Technical University Affiliated: Yes

Abstract

We present a variational two-phase constitutive model capable of capturing the enhanced rate sensitivity in nanocrystalline (nc) and ultrafine-grained (ufg) fcc metals. The nc/ufg-material consists of a grain interior phase and a grain boundary affected zone (GBAZ). The behavior of the GBAZ is described by a rate-dependent isotropic porous plasticity model, whereas a rate-independent crystal-plasticity model which accounts for the transition from partial dislocation to full dislocation mediated plasticity is employed for the grain interior. The scale bridging from a single grain to a polycrystal is done by a Taylor-type homogenization. It is shown that the enhanced rate sensitivity caused by the grain size refinement is successfully captured by the proposed model. (C) 2011 Elsevier Ltd. All rights reserved.