Effect of helium ion irradiation on pure W, W-5Ta and W-5Re: a micro-tensile and nanoindentation investigation of mechanical properties

Journal article

Micro-tensile testing has been used to study the response of pure tungsten and two tungsten alloys to helium ion irradiation. Commercially supplied plates of W, W-5Ta and W-5Re were irradiated using 6 MeV helium ions at room temperature. The ion energy was attenuated with an energy spreading device such that a uniform level of damage at 0.6 dpa (and 11,000 appm He) was deposited at the 3–9 µm depth. Focused ion beam milling was used to fabricate dog-bone shaped, micro-tensile samples 5 × 5 µm in cross-sectional area and 17 µm in length from the unirradiated and irradiated samples. All micro-tensile samples were tested at a quasi-static strain rate and the stress–strain curves were analysed to determine the mechanical properties. A close correlation was found between micro-tensile results and the bulk mechanical properties reported in the literature. Comparison between the unirradiated micro-tensile properties of W-5Re and W-5Ta with W showed that, as expected, W-5Re was softer than W whilst W-5Ta had only minor differences in micro-tensile properties compared with W. The micro-tensile results of the irradiated W, W-5Ta and W-5Re showed an increase in strength and an almost complete loss of ductility compared to the unirradiated samples. In comparing micro-tensile results to nanoindentation measurements, it was found that micro-tensile offers comparable level of precision in measurement of irradiation hardening amongst W, W-5Ta and W-5Re. The implications of the results with respect to the future performance of tungsten-based materials in the divertors in fusion reactors are discussed in detail. Graphical abstract: [Figure not available: see fulltext.]

Authors: Xu, A; Wei, T; Short, K; Palmer, T; Ionescu, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of Materials Science
• Volume: 58
• Issue: 25
• Pages: 10501-10515
• Publication date: 2023-06-22
• Acceptance date: 2023-05-29
• DOI: 10.1007/s10853-023-08647-5
• EISSN: 1573-4803
• ISSN: 0022-2461
• Language: English
• Keywords: 40 Engineering; FFR; 4016 Materials Engineering