# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1705.09327