Surface morphology of Tungsten-F82H after high-heat flux testing using plasma-arc lamps
| Autor: | Kazutoshi Tokunaga, Yutai Katoh, Yoshio Ueda, Adrian S. Sabau, M. Akiyoshi, Charles R. Schaich, James O. Kiggans, Kenzo Ibano |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Nuclear and High Energy Physics Materials science Materials Science (miscellaneous) chemistry.chemical_element Tungsten 01 natural sciences lcsh:TK9001-9401 Thermal expansion 010305 fluids & plasmas Stress (mechanics) Plasma arc welding Nuclear Energy and Engineering Heat flux chemistry 0103 physical sciences lcsh:Nuclear engineering. Atomic power Deformation (engineering) Composite material Intensity (heat transfer) Plasma-facing material |
| Zdroj: | Nuclear Materials and Energy, Vol 16, Iss, Pp 128-132 (2018) |
| ISSN: | 2352-1791 |
| Popis: | 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. Keywords: High-heat flux testing, Thermal stress, Bimetallic, Tungsten, Reduced activation steel |
| Databáze: | OpenAIRE |
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