Numerical assessment of functionally graded tungsten/EUROFER coating system for first wall applications

In this work, W coatings on EUROFER substrates with W/EUROFER FG-layer (the coating system) are investigated by means of finite element (FE) simulations considering elasto-perfectly plastic and elasto-viscoplastic material models. For determining optimal parameters of the coating system the vacuum plasma spraying (VPS) fabrication process and the operation phase of the fusion reactor are simulated. Based on the FE results creep assessment of the coating system is performed demonstrating the gain in lifetime to be expected when using a FG-layer and investigating its dependence on the thickness of the FG-layer.