Combined effects of hydrogen and thermal aging on Alloy 690

Caitlin Huotilainen, Yuriy Yagodzinskyy, Roman Mouginot, Evgenii Malitckii, Hannu Hänninen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


    Thermally treated nickel-based Alloy 690 is the material of choice for the steam generator tubes of many nuclear power plants. Thermal aging of Alloy 690 has been shown to increase intergranular carbide precipitation and at aging temperatures below 450˚C a short-range atomic level ordering of the crystal lattice can take place. The atomic ordering causes lattice contraction and increases hardness and localized strain at grain boundaries. Aging induced processes can lead to a decreased resistance to primary water stress corrosion cracking of this alloy. Six Alloy 690 material conditions, all exhibiting different levels and combinations of intergranular carbide precipitation, were evaluated in the study. Thermal desorption spectroscopy and mechanical loss spectroscopy were used to investigate the correlation between hydrogen uptake and the aging-induced phenomena of the atomic ordering and carbide precipitation, with the aim to better understand the role thermal aging and hydrogen uptake play in the primary water stress corrosion cracking of thermally treated Alloy 690.
    Original languageEnglish
    Title of host publicationProceedings of the Third International Conference on Metals and Hydrogen
    Subtitle of host publicationSteelyhydrogen 2018
    ISBN (Electronic)978-908-17942-2-0
    Publication statusPublished - May 2018
    MoE publication typeA4 Article in a conference publication
    EventThird International Conference on Metals & Hydrogen - Ghent, Belgium
    Duration: 29 May 201831 May 2018
    Conference number: 3


    ConferenceThird International Conference on Metals & Hydrogen
    Abbreviated titleSteelyHydrogen2018


    • nickel-base alloy
    • primary water stress corrosion cracking
    • short range ordering
    • hydrogen thermal desorption
    • hydrogen-induced mechanical loss spectroscopy


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