Surface morphology of Tungsten-F82H after high-heat flux testing using plasma-arc lamps

K. Ibano, A. S. Sabau, K. Tokunaga, M. Akiyoshi, J. O. Kiggans, C. R. Schaich, Y. Katoh, Y. Ueda

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Abstract

F82H reduced activation steel coated with vacuum plasma sprayed (VPS) tungsten is a candidate as a plasma facing material for main chamber components in future fusion reactors. Due to different coefficients of thermal expansion (CTE), significant thermal stresses are expected in these bimetallic materials. Thus, a major uncertainty in the performance of W/F82H components during the operation under high-heat fluxes is the effect of CTE mismatch. In this study, a high intensity plasma-arc lamp was used for high-heat flux cycling tests of W/F82H specimens. While no surface damage was observed for specimens tested for 100–200 cycles at a heat flux of 1.4 MW/m2 pulse when the backside surface temperature was maintained below 550 °C, significant cracking occurred at higher temperatures. A simple analytical model for bimetallic materials indicated that the stress in the VPS-W layer is likely to exceed its failure stress solely due to the bilayer thermal stress. A finite element analysis of the state of stress and deformation confirmed that a significant stress also would occur at the W surface due to the rigid-body like constraint imposed by the clamp, which can be the main cause of the cracking.

Original languageEnglish
Pages (from-to)128-132
Number of pages5
JournalNuclear Materials and Energy
Volume16
DOIs
Publication statusPublished - Aug 2018

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering

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    Ibano, K., Sabau, A. S., Tokunaga, K., Akiyoshi, M., Kiggans, J. O., Schaich, C. R., Katoh, Y., & Ueda, Y. (2018). Surface morphology of Tungsten-F82H after high-heat flux testing using plasma-arc lamps. Nuclear Materials and Energy, 16, 128-132. https://doi.org/10.1016/j.nme.2018.06.015