Deuterium retention and thermal conductivity in ion-beam displacement-damaged tungsten

Retention of plasma-implanted D is studied in W targets damaged by a Cu ion beam at up to 0.2 dpa with sample temperatures between 300 K and 1200 K. At a D plasma ion fluence of 10²⁴/m² on samples damaged to 0.2 dpa at 300 K, the retained D retention inventory is 4.6 × 10²⁰ D/m², about ∼5.5 times higher than in undamaged samples. The retained inventory drops to 9 × 10¹⁹ D/m² for samples damaged to 0.2 dpa at 1000 K, consistent with onset of vacancy annealing at a rate sufficient to overcome the elevated rate of ion beam damage; at a damage temperature of 1200 K retention is nearly equal to values seen in undamaged materials. A nano-scale technique provides thermal conductivity measurements from the Cu-ion beam displacement damaged region. We find the thermal conductivity of W damaged to 0.2 dpa at room temperature drops from the un-irradiated value of 182 ± 3.3 W/m K to 53 ± 8 W/m K.