Strain gradient plasticity-based modeling of hydrogen environment assisted cracking
File(s)
Accepted version
Author(s)
Martinez-Paneda, Emilio
Niordson, Christian F
Gangloff, Richard P
Type
Journal Article
Abstract
Finite element analysis of stress about a blunt crack tip, emphasizing finite strain and phenomenological and mechanism-based strain gradient plasticity (SGP) formulations, is integrated with electrochemical assessment of occluded-crack tip hydrogen (H) solubility and two H-decohesion models to predict hydrogen environment assisted crack growth properties. SGP elevates crack tip geometrically necessary dislocation density and flow stress, with enhancement declining with increasing alloy strength. Elevated hydrostatic stress promotes high-trapped H concentration for crack tip damage; it is imperative to account for SGP in H cracking models. Predictions of the threshold stress intensity factor and H-diffusion limited Stage II crack growth rate agree with experimental data for a high strength austenitic Ni-Cu superalloy (Monel®K-500) and two modern ultra-high strength martensitic steels (AerMet™100 and Ferrium™M54) stressed in 0.6 M NaCl solution over a range of applied potential. For Monel®K-500, KTH is accurately predicted versus cathodic potential using either classical or gradient-modified formulations; however, Stage II growth rate is best predicted by a SGP description of crack tip stress that justifies a critical distance of 1 μm. For steel, threshold and growth rate are best predicted using high-hydrostatic stress that exceeds 6 to 8 times alloy yield strength and extends 1 μm ahead of the crack tip. This stress is nearly achieved with a three-length phenomenological SGP formulation, but additional stress enhancement is needed, perhaps due to tip geometry or slip-microstructure.
Date Issued
2016-09-15
Date Acceptance
2016-07-11
Citation
Acta Materialia, 2016, 117 (1), pp.321-332
ISSN
1359-6454
Publisher
Elsevier
Start Page
321
End Page
332
Journal / Book Title
Acta Materialia
Volume
117
Issue
1
Copyright Statement
© 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000383005300031&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Metallurgy & Metallurgical Engineering
Materials Science
Hydrogen embrittlement
Multiscale simulations
Electrochemistry
Strain gradient plasticity
Environment-assisted cracking
STRESS-CORROSION CRACKING
HIGH-STRENGTH STEELS
ALLOY MONEL K-500
MARTENSITIC STEELS
FRACTURE-TOUGHNESS
EMBRITTLEMENT
TIP
DIFFUSION
METALS
MECHANICS
Publication Status
Published
Date Publish Online
2016-07-27