Aiming at understanding thermo-mechanical loads in the first wall of DEMO: Stress-strain evolution in a Eurofer-tungsten test component featuring a functionally graded interlayer

The analyses show that, even in a small test component, a direct RAFM steel-W joint causes enormous plastic deformation. The implementation of a functionally graded interlayer reduces stresses and strains significantly, but vertical normal stresses at the joint's circumference remain considerable. With the component geometry considered here, the graded interlayer should be at least 1 mm thick and contain 4 sublayers to appropriately redistribute stresses. Beyond a component width of 14 mm, stresses increase strongly, which may pose a risk to the applicability of large-scale FW components, too.