Decommissioning of TEXTOR: properties of the Inconel liner

The final shut-down of Tokamak Experiment for Technology Oriented Research in year 2013 created unique opportunities for multi-directional studies of in-vessel components. A set of specimens from the Inconel liner parts was collected in order to assess material properties after 26 years of exploitation. The metal surfaces were covered with up to several mu m thick co-deposits rich in boron, carbon and silicon. Detailed examination of the co-deposits and nearsurface structure of Inconel performed with Transmission Electron Microscopy (TEM) revealed: (i) stratified character of the deposits; (ii) a similar to 200 nm thick layer identified as NiSi2 phase at the interface between the deposit and Inconel substrate; (iii) changed Inconel surface layer. TEM studies of the Inconel structure revealed its polycrystalline character with a mean grain size, low dislocation density and a significant number of heterogeneously distributed primary carbides.