Crystal plasticity finite element method simulation for the nanoindentation of plasma-exposed tungsten

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Abstract

In this work, the nano-indentation of plasma-exposed tungsten is simulated at room temperature and elevated temperature (300e700 K) by the recently developed crystal plasticity finite element model. A nonlinear function is applied to characterize the depth profile of plasma-induced dislocation density in the sub-surface region. The model parameters are calibrated by comparing the simulated results with corresponding experimental data at 300 K for both the force-depth and hardness-depth relationships. Furthermore, the mechanical responses of plasma-exposed tungsten are predicted at 500 K and 700 K in order to characterize the plasma effect at the fusion-relevant operational temperature. The dominant results and conclusions are that: (1) The heterogeneously distributed dislocations in the sub-surface region induced by the plasma exposure are responsible for the increase of hardness at 300 K. (2) The plasma-induced microstructural modification does not yield to considerable increase of hardness at operational temperature. (3) The expansion of the plastic zone in the sub-surface region is, to some extent, limited by the presence of plasma-induced dislocations. Whereas, the increase of temperature can effectively reduce this limitation.

Details

Original languageEnglish
Pages (from-to)334-341
Number of pages8
JournalJournal of Nuclear Materials
Volume518
DOIs
StatePublished - 12 Mar 2019

Keywords

  • Plasma exposure, Nano-indentation, CPFEM, Tungsten, Dislocations

ID: 5247927