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

TL;DR

This study investigates how ion-beam damage affects deuterium retention and thermal conductivity in tungsten, revealing increased retention at low temperatures and significant thermal conductivity reduction due to damage.

Contribution

It provides new quantitative data on deuterium retention and thermal conductivity changes in tungsten damaged by ion beams at various temperatures.

Findings

Deuterium retention increases by ~5.5 times in damaged tungsten at 300 K.

Retention decreases with higher damage temperatures, nearly matching undamaged levels at 1200 K.

Thermal conductivity drops from 182 W/m-K to 53 W/m-K after damage.

Abstract

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 $10^{24}/m^2$ on samples damaged to 0.2 dpa at 300 K, the retained D retention inventory is $4.6x10^{20} D/m^2$, about ~5.5 times higher than in undamaged samples. The retained inventory drops to $9x10^{19} D/m^2$ 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.