Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97

The novel reduced activation ferritic/martensitic steel Eurofer 97 is employed by many concept designs for the plasma-facing first wall of EU DEMO fusion reactor. These feature precision joints between coolant piping, which an advanced laser-keyhole welding technique proposed. In this work microstructure these welds modelled combining finite element thermal analysis with precipitate kinetics modelling. Microanalysis a representative specimen via scanning electron and high-speed atomic force microscopy techniques also conducted, complimented backscatter diffraction, energy-dispersive X-ray spectroscopy, nanoindentation hardness testing. Models weld agree well results microanalysis although diameters predicted are slightly underestimated. Several large void defects were discovered within zone, cause suspected to arise from evaporation cerium-rich oxide inclusions present in as-cast during welding.