Deuterium retention in W-Cr-Y alloy: Impact of the manufacturing method and helium presence

Abstract

The retention of deuterium in tungsten-chromium-yttrium alloys, W-11.4Cr-0.6Y and W-10Cr-0.5Y, was investigated by means of in-situ thermal desorption spectroscopy (TDS). The first alloy was manufactured by field-assisted sintering technology (FAST), while W-10Cr-0.5Y alloy was produced by hot isostatic pressing followed by heat treatment (HIP+HT). Both alloys were irradiated with D3+ ions (670 eV/D) and a fluence of 1021 D/m2 at temperatures of 300, 600, 900 K. In the case of W-11.4Cr-0.6Y alloy, deuterium retention was investigated during sequential irradiation with helium (3 keV) and deuterium (670 eV/D) ions at room temperature with fluences of 1019–7 × 1022 He/m2 and 1021 D/m2, respectively. The material structure has a great influence on deuterium retention, as evidenced by the significantly increased deuterium trapping in W-11.4Cr-0.6Y alloy at both room and elevated irradiation temperatures due to the presence of high-energy trapping centers compared to W-10Cr-0.5Y alloy. In both alloys, the observed amount of deuterium released during TDS was higher than in pure tungsten. The general trend of helium influence on the deuterium retention in W-11.4Cr-0.6Y alloy is very similar to bare tungsten. Namely, deuterium retention increased until helium implantation reached a fluence of 1021He/m2, and then sharply decreased when the fluence exceeded this value.