Slip localization and hydrogen embrittlement of alloy 718

Zhenbo Zhang, Gideon Obasi, Roberto Morana, Michael Preuss

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

Abstract

In this study, detailed electron microscopy characterization was employed to investigate the plastic deformation behavior and related hydrogen induced embrittlement of a nickel-based superalloy UNS N07718 (Alloy 718). Transmission Electron Microscopy (TEM) analysis demonstrated that dislocations with slip systems of 〈110〉{111} operate in a localized manner during plastic deformation. Dislocation slip localization is further revealed by high resolution digital image correlation and Electron Channeling Contrast Imaging (ECCI) techniques, where planar dislocation boundary traces (DBTs) are observed. Both postmortem analysis of the hydrogen charged sample after slow strain rate (SSR) tension and in-situ SSR tension in a Scanning Electron Microscope (SEM) show that cracks tend to initiate and propagate along the DBTs, where dislocation slip localization happens. This phenomenon is rationalized by the evident nucleation of nanoscale voids along the dislocation boundaries, especially at the intersections between non-parallel dislocation boundaries. Hydrogen enhanced localized plasticity, which associates with intensive hydrogen-dislocation interaction, is suggested to be the dominant reason for the hydrogen embrittlement of Alloy 718.

Original languageEnglish
Title of host publicationSuperalloys 2016
Subtitle of host publicationProceedings of the 13th International Symposium on Superalloys
EditorsMark Hardy, Eric Huron, Uwe Glatzel, Brian Griffin, Beth Lewis, Cathie Rae, Venkat Seetharaman, Sammy Tin
PublisherThe Minerals, Metals & Materials Society
Pages939-947
Number of pages9
ISBN (Electronic)9781118996669
DOIs
Publication statusPublished - 2016
Externally publishedYes
EventInternational Symposium on Superalloys 2016 - Seven Springs, United States of America
Duration: 11 Sep 201615 Sep 2016
Conference number: 13th

Publication series

NameProceedings of the International Symposium on Superalloys
Volume2016-January

Conference

ConferenceInternational Symposium on Superalloys 2016
Abbreviated titleSuperalloys 2016
CountryUnited States of America
CitySeven Springs
Period11/09/1615/09/16

Keywords

  • Electron channeling contrast imaging
  • Hydrogen embrittlement
  • Slip localization
  • Superalloy

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