NSUF 16-623: A comparison of mechanical properties of ion and neutron irradiated Fe-9Cr
In nuclear materials testing heavy ion irradiation is commonly used to simulate neutron irradiation, where practical considerations make the latter unfeasible. This work will compare the mechanical properties of samples irradiated with heavy ions with those irradiated with neutrons under otherwise as similar as possible conditions, with the aim of correlating the two irradiation methods. Among the differences between the two irradiation experiments, and an unavoidable difference in any simulation technique, is damage rate. Fe-Cr alloys ion irradiated with different damage rates have been shown to have significant differences in post-irradiation hardness. Neutron irradiation provides an opportunity to study material irradiated at a much lower damage rate than is possible with ion irradiation. Alongside the correlation with ion irradiation experiments and the effect of dose rate, this work will study radiation damamge in Fe-9Cr, which has particular relevance to the Eurofer reduced activation ferritic martensitic (RAFM) alloy, a candidate material for use in fusion reactors. The FIB time requested at the CAES facility will be used to mill microcantilevers in the neutron irradiated specimen(shipped to CAES by UCSB), and to then image them using the electron beam for stereoscopic measurement. Microcantilevers are time consuming to produce to the required high standard, hence the maximum 6 days requested. Although the team member performing this work has experience using other FIB equipment, some initial training/supervision will be required. After this FIB work is complete, the sample will be shipped (funded outside of this proposal) to the Culham Centre for Fusion Energy (CCFE) in order to use the nanoindenter there to perform nanoindentation and testing of the microcantilevers to measure the yield stress of the material. The corresponding work for the ion irradiated specimen will be performed at Oxford/CCFE, as no hot facility is required. Prior to any FIB work, the neutron irradiated samples will require polishing to obtain a high quality surface finish (suitable for EBSD analysis) which is essential for the near surface mechanical testing outlined above. The ion irradiated samples were prepared using a series of grit papers to 4000 grade, and then polished using diamond pastes of 9, 6, 3, and 1 µm grade. A final polish was performed with colloidal silica. A similar procedure for the neutron irradiated samples would be performed during the requested 1 day access to preparation facilities at CAES. Due to the radioactive nature of the sample, extensive assistance will be required during this stage.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | University of Oxford |
| Embargo End Date | 2026-02-27 |
| Facility Tech Lead | Mukesh Bachhav |
| NSUF Call | FY 2016 RTE 1st Call |
| PI | Steve Roberts |
| Project Member | Dr. Steve Roberts - University of Oxford |
| Project Member | Luke Hewitt - University of Oxford |
| Project Member | Chris Hardie - UK Atomic Energy Authority |
| Project Type | RTE |
| Publication | Mechanical properties and plasticity size effect of Fe-6%Cr irradiated by Fe ions and by neutrons G. Robert Odette, Chris Hardie, Steve Roberts Journal of Nuclear Materials 482 2016-12-15 http://www.sciencedirect.com/science/article/pii/S0022311516309515 |
| RTE Number | 623 |