Hydrogen is susceptible to modify mechanisms of stress corrosion cracking of alloy 718 component structure elements in Pressurized Water Reactors (PWR), during service at temperatures from 80°C to 340°C. In order to study hydrogen embrittlement susceptibility of alloy 718, samples have been firstly cathodically charged in hydrogen in molten salts (NaHSO4, 46.5% wt. – KHSO4, 53.5% wt.) at 150°C. After charging, tensile tests were carried out at 80°C, 150°C and 300°C for a constant strain rate of 5x10-4s-1. Quantification of hydrogen embrittlement was performed by the analysis of rupture modes and elongation to failure. Rupture mode identification and tensile tests evidenced a maximal susceptibility to hydrogen embrittlement at 80°C whereas hydrogen effect was less noticeable at 300°C. From these results, the evolution of hydrogen location and interaction with deformation as a function of temperature was then discussed. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.
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