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

Abstract

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