Fracture behavior of tungsten-based composites exposed to steadystate/ transient hydrogen plasma

Research output: Contribution to report/book/conference proceedingsIn-proceedings paper

Authors

  • Y. Li
  • T.W. Morgan
  • J.A.W. van Dommelen
  • Steffen Antusch
  • Michael Rieth
  • J.P.M. Hoefnagels
  • Dmitry Terentyev
  • Gregory De Temmerman
  • Kim Verbeken
  • M.G.D. Geers

Institutes & Expert groups

  • Technische Universiteit Eindhoven - FOM Institute DIFFER
  • TU/E - Eindhoven University of Technology
  • UGent - Universiteit Gent
  • IKET KIT INE - Karlsruhe Institute of : Institute for Nuclear Waste Disposal
  • ITER - Organization - France

Documents & links

DOI

Abstract

The fracture behavior of plasma-facing components (PFCs) under extreme plasma-material interaction conditions is of great concern to ITER and future fusion reactors. This was explored in the current study by exposing pure tungsten (W), W-1%TiC and W-2%Y2O3 composites to a combined steady-state/transient hydrogen plasma up to a base surface temperature of ~ 2220 K, and up to 5000 transient pulses for 1000 seconds using the linear plasma generator Magnum-PSI. The applied heat loads were characterized by combining sheath physics, thermographic information and finite element analyses, with which the thermal stress was evaluated. Combining microstructural investigation and thermo-mechanical numerical analyses, a physical picture of fracture is developed. The transient heat loads drive surface crack initiation, whose depth can be estimated by a simple analytical model for pure tungsten, while the cooling period following the steady-state heat load induces tensile stresses, opening existing surface cracks deeper. The fracture process is mediated by the microstructure whereby the ceramic particles stabilize the microstructure but promote surface crack initiation due to suppressed plasticity at the grain boundaries and the particle-matrix interfaces. The surface cracks relieve the subsequent cycles of transient thermal stress but intensify the steady-state thermal stress, therefore, promoting deep crack propagation. These results help to understand failure mechanisms in PFCs under extreme operation conditions which are valuable for developing advanced PFCs.

Details

Original languageEnglish
Title of host publicationNuclear Fusion
Place of PublicationVienna
PublisherIAEA - International Atomic Energy Agency
Pages1-34
Number of pages34
Volume60/4
Edition2020
DOIs
Publication statusPublished - 16 Mar 2020

Publication series

NameNuclear Fusion
PublisherIOP - IOP Publishing
ISSN (Print)0029-5515

Keywords

  • Tungsten, ITER, Tungsten alloys, Pure W, Hydrogen, Fracture

ID: 6785402