Effect of hydrogen on the mechanical properties of alloy 945X (UNS N09945) and influence of microstructural features

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:684

Article

Demetriou, V.^1,2  Robson, J. D.¹  Preuss, M.^1,2  Morana, R.^2,3 

[1] Univ Manchester, Sch Mat, Manchester M13 9PL, Lancs, England

[2] BP Int Ctr Adv Mat, London, England

[3] BP Explorat & Prod, Sunbury On Thames, Middx, England

关键词: Alloy 945X;    Hydrogen Embrittlement;    delta phase;    Tensile properties;    Precipitation hardening;    Slip bands;   

DOI  :  10.1016/j.msea.2016.12.088

来源: Elsevier

【 摘 要 】

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 gamma', gamma '' and delta 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 delta-phase at grain boundaries. There was no simple correlation between the volume fraction of delta-phase and susceptibility to hydrogen assisted embrittlement. Rather, it was demonstrated that the morphology and distribution of delta-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.

【 授权许可】

Free