2026-04-28T06:15:23Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/56672023-01-09T07:45:56Zcom_10259_4201com_10259_5086com_10259_2604col_10259_4505

Díaz Portugal, Andrés 147 500 0000-0002-2344-1955 Zafra, A. 2dc2bec1-7a02-498e-bdb9-c5c995fc5a72 600 Martínez Pañeda, Emilio 0e268b17-776b-4013-868b-7f8417bf1088 500 Alegre Calderón, Jesús Manuel 16 500 0000-0003-3629-2570 Belzunce, J. f422067e-1ca8-4880-8872-00ceb41fa80a 500 Cuesta Segura, Isidoro Iván 135 500 0000-0003-4088-9302 2021-03-24T12:46:12Z 2021-03-24T12:46:12Z 2020-12 0167-8442 http://hdl.handle.net/10259/5667 10.1016/j.tafmec.2020.102818 There is a need for numerical models capable of predicting local accumulation of hydrogen near stress concentrators and crack tips to prevent and mitigate hydrogen assisted fracture in steels. The experimental characterisation of trapping parameters in metals, which is required for an accurate simulation of hydrogen transport, is usually performed through the electropermeation test. In order to study grain size influence and grain boundary trapping during permeation, two modelling approaches are explored; a 1D Finite Element model including trap density and binding energy as input parameters and a polycrystalline model based on the assignment of a lower diffusivity and solubility to the grain boundaries. Samples of pure iron after two different heat treatments – 950 °C for 40 min and 1100 °C for 5 min – are tested applying three consecutive rising permeation steps and three decaying steps. Experimental results show that the finer grain microstructure promotes a diffusion delay due to grain boundary trapping. The usual methodology for the determination of trap densities and binding energies is revisited in which the limiting diluted and saturated cases are considered. To this purpose, apparent diffusivities are fitted including also the influence of boundary conditions and comparing results provided by the constant concentration with the constant flux assumption. Grain boundaries are characterised for pure iron with a binding energy between 37.8 and 39.9 kJ/mol and a low trap density but it is numerically demonstrated that saturated or diluted assumptions are not always verified, and a univocal determination of trapping parameters requires a broader range of charging conditions for permeation. The relationship between surface parameters, i.e. charging current, recombination current and surface concentrations, is also studied showing that trapping phenomena are stronger during the diluted steps and that recombination currents are much higher than the steady state obtained flux. Ministry of Economy and Competitiveness of Spain through gran RTI2018-096070-B-C33. E. Martínez-Pañeda also acknowledges financial support from EPSRC funding under grant No. EP/R010161/1 and from the UKCRIC Coordination Node, EPSRC grant number EP/R017727/1, which funds UKCRIC’s ongoing coordination. application/pdf eng Elsevier Theoretical and Applied Fracture Mechanics. 2020, V. 110, 102818 https://doi.org/10.1016/j.tafmec.2020.102818 info:eu-repo/grantAgreement/MINECO/RTI2018-096070-B-C33 Attribution-NonCommercial-NoDerivatives 4.0 Internacional http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Hydrogen embrittlement Hydrogen trapping Hydrogen permeation Finite Element modelling Resistencia de materiales Strength of materials Simulation of hydrogen permeation through pure iron for trapping and surface phenomena characterisation info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Theoretical and Applied Fracture Mechanics 110 102818 TEXT Diaz-tafm_2020.pdf.txt Diaz-tafm_2020.pdf.txt Extracted text text/plain 73199 https://riubu.ubu.es/bitstream/10259/5667/5/Diaz-tafm_2020.pdf.txt 8f5c2bacfc69541c0e7d8c8fe84924c8 MD5 5 THUMBNAIL Diaz-tafm_2020.pdf.jpg Diaz-tafm_2020.pdf.jpg IM Thumbnail image/jpeg 4537 https://riubu.ubu.es/bitstream/10259/5667/4/Diaz-tafm_2020.pdf.jpg 77b6e2342de71353b35a01be89bab71a MD5 4 LICENSE license.txt license.txt text/plain; charset=utf-8 999 https://riubu.ubu.es/bitstream/10259/5667/3/license.txt b295bcbce42e2caabeb0c623d3860c06 MD5 3 CC-LICENSE license_rdf license_rdf application/rdf+xml; charset=utf-8 805 https://riubu.ubu.es/bitstream/10259/5667/2/license_rdf 4460e5956bc1d1639be9ae6146a50347 MD5 2 ORIGINAL Diaz-tafm_2020.pdf Diaz-tafm_2020.pdf application/pdf 4236012 https://riubu.ubu.es/bitstream/10259/5667/1/Diaz-tafm_2020.pdf 9972848f9de337971740cd14da5b8194 MD5 1 10259/5667 oai:riubu.ubu.es:10259/5667 2023-01-09 08:45:56.123 Repositorio Institucional de la Universidad de Burgos bubrep@ubu.es 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