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The Importance of Transient Effects Resulting from Dislocation Transport of Hydrogen

  • I. M. Bernstein
  • A. W. Thompson

Abstract

A number of authors have recently considered whether or not dissolved hydrogen, when associated with mobile dislocations, either as a Cottrell atmosphere or as a dislocation core population, can be transported to local imhomogeneities (denoted as traps) in the lattice or grain boundary.1–3 These considerations have focused on the ability of these moving hydrogen sources4 to provide a mechanism for either or both local enrichment, or pressurization resulting from molecular hydrogen formation,5–9 in excess of the amount predicted from thermodynamic equilibrium of the internal hydrogen with the external fugacity. Because of the potential importance of such processes to hydrogen embrittlement, and because much of the ensuing debate has become enmeshed in justifying the validity of the details of a particular theoretical approach, we are concerned that the broader, more important issues have been neglected. Namely, are there materials, or variable ranges in a given material, where dissolved hydrogen can interact with mobile dislocations, can be then transported to local heterogeneities, and be deposited to enrich the local non-equilibrium hydrogen concentration, and possibly recombine to molecular hydrogen, with an associated large volume change and pressurization? Further, can such processes provide an accelerating step for the occurrence or severity of hydrogen embrittlement? We believe that the answer to both queries is yes, but only for very specific conditions, a point emphasized previously.1,3,8

Keywords

Fracture Mode Hydrogen Embrittlement Void Growth Mobile Dislocation Cathodic Charge 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • I. M. Bernstein
    • 1
  • A. W. Thompson
    • 1
  1. 1.Dept. of Metallurgical Engineering and Materials ScienceCarnegie-Mellon UniversityPittsburghUSA

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