Thermo-mechanical and thermal shock characterization of potassium doped tungsten

One potential plasma facing material candidate for future nuclear fusion facilities and reactors like ITER and especially DEMO is potassium doped tungsten, better known from lighting industry. Herein, in particular the potassium doped tungsten grade WVMW produced by PLANSEE AG is qualified in its asreceived and annealed/recrystallized state (annealing at 1800 C) and compared with a standard W-rod. One qualification criteria is the crack formation under fusion relevant short transient events which is addressed by single and multiple thermal shock loading in the electron beam facility JUDITH at different power densities and base temperatures. Therein annealed WVMW is showing the best performance with the lowest transition temperature from crack formation to no crack formation between 150 and 200 C. This might be also taken as a measure for the ductility and the DBTT of the material. For a better understanding of the cracking process as well as for the establishment of a data base for finite element modelling tensile tests are performed up to 2000 C and at different speed (0.2 and 42 mm/min).