V. Kuksenko S. Roberts E. Tarleton
Four industrial beryllium grades were tested via nanoindentation. An extremely high variation of hardness was observed in all samples. Analysis of the nanoindentation data in combination with SEM/EBSD measurements demonstrated that the crystallographic orientation of the indented grain was the major source of the wide variation in hardness, which w…
Preprint PublishedY. Zayachuk D.E.J. Armstrong K. Bystrov S. Van Boxel T. Morgan S. G. Roberts
Tungsten samples were heat-treated to achieve partial recrystallization and exposed to high ion flux deuterium plasma at different temperatures and fluences. Continuous stiffness nanoindentation measurements of near-surface hardness were performed in the grains of specific annealing states and of specific crystallographic orientation, determined by…
Preprint PublishedX. Yi K. Arakawa D. Nguyen-Manh F. Ferroni P. Liu W. Han F. Wan S. G. Roberts
Helium bubble production in tungsten has been studied combining transmission electron microscopy and in situ irradiations with 10 keV He+ ions. The irradiations were carried out at four temperatures (773 K, 1073 K, 1273 K, 1473 K), and were held at intervals of (0.45; 0.9; 1.2; 1.5) × 1020 He+/m2 for each temperature. Based on detailed analyses of…
Preprint PublishedT. R. Barrett G. Ellwood G. Pérez M. Kovari M. Fursdon F. Domptail S. Kirk S.C. McIntosh S. Roberts S. Zheng L.V. Boccaccini J-H. You C. Bachmann J. Reiser M. Rieth E. Visca G. Mazzone F. Arbeiter P.K. Domalapally
The European DEMO power reactor is currently under conceptual design within the EUROfusion Consortium. One of the most critical activities is the engineering of the plasma-facing components (PFCs) covering the plasma chamber wall, which must operate reliably in an extreme environment of neutron irradiation and surface heat and particle flux, while …
Preprint PublishedA. Xu D.E.J. Armstrong C. Beck M. P. Moody G. D.W. Smith P. A. J. Bagot S. G. Roberts
In tungsten plasma-facing fusion reactor components, Ta is the third most abundant element formed by transmutation (after Re and Os), yet little is known about the behaviour of W-Ta alloys under irradiation and any effects Ta might have on Re clustering in W-Re-Ta alloys. In this study, W-4.5 at.%Ta, W-2 at.% Re-1 at.%Ta andW-2 at.%Re alloys were e…
PublishedY. Zayachuk I. Tanyeli S. Van Boxel K. Bystrov T. W. Morgan S.G. Roberts
For tungsten exposed to low-energy hydrogen-plasmas, it has been thought that grains with surface normal are most susceptible to blistering while those with surface normal are virtually impervious to it. Here, we report results showing that non-uniformity of blister distribution depends on the state of the surface due to polishing. In e…
Preprint PublishedX. Yi A.E. Sand D.R. Mason M.A. Kirk S.G. Roberts K. Nordlund S.L. Dudarev
Using in-situ transmission electron microscopy, we have directly observed nano-scale defects formed in ultra-high purity tungsten by low-dose high energy self-ion irradiation at 30K. At cryogenic temperature lattice defects have reduced mobility, so these microscope observations over a window on the initial, primary damage caused by individual coll…
Preprint PublishedA. Xu C. Beck D. E. J. Armstrong K. Rajan G. D.W. Smith P. A. J. Bagot S. G. Roberts
This study examines clustering and hardening in W–2 at.% Re and W–1 at.% Re–1 at.% Os alloys induced by 2 MeV W + ion irradiation at 573 and 773 K. Such clusters are known precursors to the formation of embrittling precipitates, a potentially life-limiting phenomenon in the oper- ation of fusion reactor components. Increases in hardness were …
PublishedJ. S. K. L. Gibson S. G. Roberts D. E. J. Armstrong
Nanoindentation has been performed on tungsten, unimplanted and helium-implanted to $ 600 appm, at temperatures up to 750 1 C. The hardening effect of the damage was 0.90 GPa at 50 1 C, but is negligible above 450 1 C. The hardness value at a given temperature did not change on re-testing after heating to 750 1 C. This suggests that the helium is t…
PublishedC.D. Hardie S.G. Roberts A.J. Bushby
The effects of ion irradiation in materials for research are usually limited to a shallow surface layer of the order of one micrometre in depth. Determining the mechanical properties of such irradiated materials requires techniques with high spatial resolution. Nanoindentation is a relatively simple method for investigating these shallow layers wit…
Preprint Published