Constitutive law for thermally-activated plasticity of recrystallized tungsten

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Institutes & Expert groups

  • UCL - Université Catholique de Louvain - IMMC - Institute of Mechanics, Materials and Civil Engineering - Belgium
  • UGent - University Ghent - Department of Applied Physics

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DOI

Abstract

A physically-based constitutive law relevant for ITER-specification tungsten grade in as-recrystallized state is proposed. The material demonstrates stages III and IV of the plastic deformation, in which hardening rate does not drop to zero with the increase of applied stress. Despite the classical Kocks- Mecking model, valid at stage III, the strain hardening asymptotically decreases resembling a hyperbolic function. The material parameters are fitted by relying on tensile test data and by requiring that the strain and stress at the onset of diffuse necking (uniform elongation and ultimate tensile strength correspondingly) as well as the yield stress be reproduced. The model is then validated in the temperature range 300e600 C with the help of finite element analysis of tensile tests which confirms the reproducibility of the experimental engineering curves up to the onset of diffuse necking, beyond which the development of ductile damage accelerates the material failure. This temperature range represents the low temperature application window for tungsten as divertor material in fusion reactor ITER.

Details

Original languageEnglish
Pages (from-to)658-332
Number of pages8
JournalJournal of Nuclear Materials
Volume496
DOIs
StatePublished - 3 Oct 2017

Keywords

  • recrystallized W, low temperature, deformation , stage IV, model validation, finite element analaysis

ID: 3368142