Correlation between Cu precipitates and irradiation defects in Fe-Cu model alloys investigated by positron annihilation spectroscopy

The correlation between Cu precipitates and vacancy-like defects in three Fe-Cu model alloys, Fe-0.15%Cu, Fe-03%Cu and Fe-0.6%Cu, irradiated at 400 degrees C with hydrogen ions at doses from 0.045 to 0.45 dpa, were revealed by positron annihilation spectroscopy. The formation of vacancy-like defects surrounded by tiny Cu precipitates induced the increment of the S and W parameters after irradiation. The peak value of the relative W parameter (triangle W/W), as the high momentum information on Cu precipitates, located in the track region and decreased with irradiation dose increased from 0.045 dpa to 0.45 dpa. The information on high momentum depended on the coverage fraction of the defects by Cu atoms. The effect of the irradiation dose, the irradiation depth and the Cu content on the Cu coverage fraction of the defects has been investigated in the present work. (c) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.