Novel Methods for Recording Stress-Strain Curves in Proton Irradiated Material.

Proton irradiation is often used as a proxy for neutron irradiation but the irradiated layer is typically <50 μm deep; this presents a problem when trying to obtain mechanical test data as a function of irradiation level. Two novel methodologies have been developed to record stress-strain curves for thin proton-irradiated surface layers of SA-508-4N ferritic steel. In the first case, in-situ loading experiments are carried out using a combination of X-ray diffraction and digital image correlation on the near surface region in order to measure stress and strain, thereby eliminating the influence of the non-irradiated volume.

Quantitative methods for the APT analysis of thermally aged RPV steels.

Atom Probe Tomography (APT) is extensively used for the analysis of RPV steels. However, many different analysis methods and cluster search parameters are used, making comparisons between different datasets difficult. Suitable d(max) and N(min) parameters for the maximum separation method are investigated.