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Demetriou V., Robson J.D., Preuss M., Morana R.: Effect of Hydrogen on the Mechanical Properties of Alloy 945X (UNS N09945) and Influence of Microstructural Features, Materials Science and Engineering: A, Vol. 684, 2017, pp. 423-434


This study investigated the hydrogen embrittlement sensitivity of the precipitation hardened (PH) alloy 945X in three different metallurgical states. The three variants examined (obtained by different heat treatments) were the standard oil and gas industry condition, and two alternative microstructures with variations in fraction and morphology of γ′, γ″ and δ phases. For each metallurgical state, mechanical tests were carried out on both uncharged and hydrogen pre-charged specimens in order to evaluate the deleterious influence of hydrogen on mechanical properties. Material characterisation and post-test fractography was performed to understand the link between microstructural features, fracture behaviour, and susceptibility to hydrogen embrittlement. Fractographic analysis showed that, in the presence of hydrogen, intergranular fracture occurred for all the heat treatments, regardless the presence of δ-phase at grain boundaries. There was no simple correlation between the volume fraction of δ-phase and susceptibility to hydrogen assisted embrittlement. Rather, it was demonstrated that the morphology and distribution of δ-phase along grain boundaries plays a key role and the other precipitate phases also have an influence through their influence on the ease of strain localization.

Paper – Link at Elsevier, free to download for 6 weeks (click on text)

Copyright © 2017 Elsevier. All rights reserved.

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The Network of Excellence (NoE) in Hydrogen Embrittlement


The Network of Excellence (NoE) in Hydrogen Embrittlement aims to strengthen scientific and technological excellence by developing an integrated and interdisciplinary scientific approach, and also by addressing the fragmentation of European and Worldwide research in this area.

The Network of Excellence in Hydrogen Embrittlement is structured so that it consists of the following branches:

  1. Hydrogen Embrittlement Group on LinkedIn
  2. Hydrogen Embrittlement  – Understanding and research framework Project  on ResearchGate
  3. Hydrogen Embrittlement Group on Mendeley
  4. Hydrogen Embrittlement and Materials Science Blog on WordPress
  5. Research Topic titled “Hydrogen Embrittlement Mechanisms” (now closed) in collaboration with Frontiers in Materials Journal within Corrosion Research section
  6. Damage and Fracture Mechanism Group on LinkedIn

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Hydrogen Embrittlement & Materials Science by Milos Djukic is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.