Abstract
Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.
| Original language | English |
|---|---|
| Pages (from-to) | 66-74 |
| Number of pages | 9 |
| Journal | Journal of Nuclear Materials |
| Volume | 490 |
| DOIs | |
| State | Published - Jul 1 2017 |
Funding
This work was supported by the Office of Fusion Energy Sciences, U.S. Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC, and the U.S./Japan PHENIX project on fusion research and development. A portion of this research used resources at the HFIR, a Department of Energy Office of Science User Facility operated by the ORNL. The authors would like to thank Dr. J. Reiser at Karlsruhe Institute of Technology, Germany, for providing W foil material. The authors are grateful to Dr. P. D. Edmondson at Oak Ridge National Laboratory for his valuable comments.