B5 Technology Tasks

5.1 Detailed metallurgical characterisation (including ageing effects) of the EU ODS steel (TW3 TTMS 006-deliverable 2)

Background and Objectives: The scope of this task is to characterise the EU ODS Eurofer steel using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDAX) and Transmission Electron Microscopy (TEM) with EDAX and electron energy loss spectroscopy (EELS). The work for this task involves measurement of the samples in the as-received condition and after different annealing conditions. The annealing includes isochronal and isothermal ageing under vacuum.

Work performed in year 2007: X-ray diffraction and Transmission Electron Microscopy measurements have been completed in all delivered samples in as received condition and heat treated. Analysis of the measurements has been carried out. Isochronal ageing under vacuum has been carried out in the heat treated samples for 1 hour at 500 and 700°C and for 70 hours at 700 and 800°C. Isothermal ageing was carried out at 700°C for 1 and 70 hours. XRD measurements were performed on all the aged samples and the structural changes were determined. In addition TEM measurements with EDX, EELS and Energy Filtering was carried on the aged samples. The matrix structure, the precipitation formation and the Y2O3 nanoparticles size distribution were characterised and were compared to those of the non-aged samples. The study was completed and the final report was sent for approval. (Details can be found in Annex XXXIII.)