Journal Article

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

Palmer, Tim, Bhattacharyya, Dhriti, Smith, George D. W., Ionescu, Mihail, Wei, Tao, Short, Ken, Armstrong, David E. J., Xu, Alan

2023

Overview

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

• Publisher: Springer US,Springer,Springer Nature B.V
• Subject: ambient temperature / Analysis / Characterization and Evaluation of Materials / Chemistry and Materials Science / Classical Mechanics / Crystallography and Scattering Methods / deformation / Divertors (fusion reactors) / energy / Fusion reactors / helium / Helium ions / Investigations / Ion beams / Ion irradiation / irradiation / Materials Science / Mechanical properties / Metals & Corrosion / Nanoindentation / Nuclear energy / Nuclear fuel cycle / Polymer Sciences / Room temperature / Solid Mechanics / Strain analysis / Strain rate / Stress-strain curves / Tensile properties / Tensile tests / tungsten / Tungsten alloys / Tungsten base alloys