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IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE / ROBERTO ANDRADE

Swansea University Author: ROBERTO ANDRADE

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Abstract

Stress Corrosion Cracking (SCC) is a type of material degradation characterised by the combined effect of tensile stress and localised corrosion produced by aggressive ions such as chlorides. It is very difficult to detect and has caused catastrophic failures of components in service at diverse indu...

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Published: Swansea University, Wales, UK 2024
Institution: Swansea University
Degree level: Master of Research
Degree name: MSc by Research
Supervisor: Williams, G
URI: https://cronfa.swan.ac.uk/Record/cronfa66610
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fullrecord <?xml version="1.0" encoding="utf-8"?><rfc1807 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><bib-version>v2</bib-version><id>66610</id><entry>2024-06-07</entry><title>IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE</title><swanseaauthors><author><sid>12f91bcd3e2987a78455689f13e32a8e</sid><firstname>ROBERTO</firstname><surname>ANDRADE</surname><name>ROBERTO ANDRADE</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2024-06-07</date><abstract>Stress Corrosion Cracking (SCC) is a type of material degradation characterised by the combined effect of tensile stress and localised corrosion produced by aggressive ions such as chlorides. It is very difficult to detect and has caused catastrophic failures of components in service at diverse industries. Several researchers have investigated this phenomenon using different approaches, but therole of the stress in the initiation and propagation stage is still not fully understood.Previous studies have shown that the scanning vibrating electrode technique (SVET) can be used to map pitting corrosion sites on austenitic stainless steels (SS) in nonstrained conditions. The present research looks to expand the scope of this technique, employing SVET analysis of strained and non-strained samples of 304 SS- in the annealed and thermally sensitised condition. Such samples were tested in 3 M and 4 M MgCl2 concentrations, aiming to obtain relevant data that can improvethe understanding of the role of stress in the initiation of pitting corrosion.As part of the experiments carried out, droplet tests were performed on annealed and sensitised samples under strained and non-strained conditions, determining that 4 M MgCl2 was the ideal concentration whereby spontaneous formation of pits in open circuit conditions was reproducibly observed. Subsequently, the samples were immersed in this chloride electrolyte and the localised corrosion behaviour was studied in-situ using the SVET. The current density maps obtained showed that applied strain can decrease the decay rate of anodic current density for the propagating pits compared with the un-strained surface. Additionally, these results were complemented with potentiodynamic polarisation, optical microscopy, scanning electron microscopy and height-depth microscopy, which showed morphologies and other relevant characteristics. The results obtained could open new research lines to investigate the role of stress in the initiation of SCC in nuclearcladding alloys.In a separate experiment, the localised corrosion characteristics of coupons consisting of a bespoke nuclear cladding alloy (20Cr/25Ni/Nb) electron beam welded to a simulant sensitised grain boundary alloy (45Fe/45Ni/10Cr) was carried out. The tests performed included potentiodynamic polarisation studies of the alloy, weld, and simulant grain boundary regions separately along with, SVET andSKP analysis of the test coupon as a whole. Spatially resolved SKP-derived maps determined the relative nobility of the cladding in comparison to the simulant alloy, and SVET studies showed that the weld joint was most susceptible to localised corrosion initiation under immersion conditions.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea University, Wales, UK</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Localised Corrosion, Pitting Corrosion, SCC, SVET, Corrosion under strain</keywords><publishedDay>8</publishedDay><publishedMonth>4</publishedMonth><publishedYear>2024</publishedYear><publishedDate>2024-04-08</publishedDate><doi/><url/><notes>A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information.</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Williams, G</supervisor><degreelevel>Master of Research</degreelevel><degreename>MSc by Research</degreename><degreesponsorsfunders>EPSRC, WEFO, National Nuclear Laboratory (NNL)</degreesponsorsfunders><apcterm/><funders>EPSRC, WEFO, National Nuclear Laboratory (NNL)</funders><projectreference/><lastEdited>2024-06-07T15:46:37.3038312</lastEdited><Created>2024-06-07T15:12:12.5088951</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Materials Science and Engineering</level></path><authors><author><firstname>ROBERTO</firstname><surname>ANDRADE</surname><order>1</order></author></authors><documents><document><filename>66610__30576__b1a80a14d50c446a88ba5d784ddfb320.pdf</filename><originalFilename>2024_Andrade_R.final.66610.pdf</originalFilename><uploaded>2024-06-07T15:25:06.1333791</uploaded><type>Output</type><contentLength>4802751</contentLength><contentType>application/pdf</contentType><version>E-Thesis – open access</version><cronfaStatus>true</cronfaStatus><documentNotes>Copyright: The Author, Roberto Alcivar Andrade, 2024</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language></document></documents><OutputDurs/></rfc1807>
spelling v2 66610 2024-06-07 IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE 12f91bcd3e2987a78455689f13e32a8e ROBERTO ANDRADE ROBERTO ANDRADE true false 2024-06-07 Stress Corrosion Cracking (SCC) is a type of material degradation characterised by the combined effect of tensile stress and localised corrosion produced by aggressive ions such as chlorides. It is very difficult to detect and has caused catastrophic failures of components in service at diverse industries. Several researchers have investigated this phenomenon using different approaches, but therole of the stress in the initiation and propagation stage is still not fully understood.Previous studies have shown that the scanning vibrating electrode technique (SVET) can be used to map pitting corrosion sites on austenitic stainless steels (SS) in nonstrained conditions. The present research looks to expand the scope of this technique, employing SVET analysis of strained and non-strained samples of 304 SS- in the annealed and thermally sensitised condition. Such samples were tested in 3 M and 4 M MgCl2 concentrations, aiming to obtain relevant data that can improvethe understanding of the role of stress in the initiation of pitting corrosion.As part of the experiments carried out, droplet tests were performed on annealed and sensitised samples under strained and non-strained conditions, determining that 4 M MgCl2 was the ideal concentration whereby spontaneous formation of pits in open circuit conditions was reproducibly observed. Subsequently, the samples were immersed in this chloride electrolyte and the localised corrosion behaviour was studied in-situ using the SVET. The current density maps obtained showed that applied strain can decrease the decay rate of anodic current density for the propagating pits compared with the un-strained surface. Additionally, these results were complemented with potentiodynamic polarisation, optical microscopy, scanning electron microscopy and height-depth microscopy, which showed morphologies and other relevant characteristics. The results obtained could open new research lines to investigate the role of stress in the initiation of SCC in nuclearcladding alloys.In a separate experiment, the localised corrosion characteristics of coupons consisting of a bespoke nuclear cladding alloy (20Cr/25Ni/Nb) electron beam welded to a simulant sensitised grain boundary alloy (45Fe/45Ni/10Cr) was carried out. The tests performed included potentiodynamic polarisation studies of the alloy, weld, and simulant grain boundary regions separately along with, SVET andSKP analysis of the test coupon as a whole. Spatially resolved SKP-derived maps determined the relative nobility of the cladding in comparison to the simulant alloy, and SVET studies showed that the weld joint was most susceptible to localised corrosion initiation under immersion conditions. E-Thesis Swansea University, Wales, UK Localised Corrosion, Pitting Corrosion, SCC, SVET, Corrosion under strain 8 4 2024 2024-04-08 A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. COLLEGE NANME COLLEGE CODE Swansea University Williams, G Master of Research MSc by Research EPSRC, WEFO, National Nuclear Laboratory (NNL) EPSRC, WEFO, National Nuclear Laboratory (NNL) 2024-06-07T15:46:37.3038312 2024-06-07T15:12:12.5088951 Faculty of Science and Engineering School of Engineering and Applied Sciences - Materials Science and Engineering ROBERTO ANDRADE 1 66610__30576__b1a80a14d50c446a88ba5d784ddfb320.pdf 2024_Andrade_R.final.66610.pdf 2024-06-07T15:25:06.1333791 Output 4802751 application/pdf E-Thesis – open access true Copyright: The Author, Roberto Alcivar Andrade, 2024 true eng
title IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
spellingShingle IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
ROBERTO ANDRADE
title_short IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
title_full IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
title_fullStr IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
title_full_unstemmed IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
title_sort IN-SITU MAPPING OF LOCALISED CORROSION UNDER THE EFFECT OF STRAIN USING A SCANNING VIBRATING ELECTRODE TECHNIQUE
author_id_str_mv 12f91bcd3e2987a78455689f13e32a8e
author_id_fullname_str_mv 12f91bcd3e2987a78455689f13e32a8e_***_ROBERTO ANDRADE
author ROBERTO ANDRADE
author2 ROBERTO ANDRADE
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institution Swansea University
college_str Faculty of Science and Engineering
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hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Materials Science and Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Materials Science and Engineering
document_store_str 1
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description Stress Corrosion Cracking (SCC) is a type of material degradation characterised by the combined effect of tensile stress and localised corrosion produced by aggressive ions such as chlorides. It is very difficult to detect and has caused catastrophic failures of components in service at diverse industries. Several researchers have investigated this phenomenon using different approaches, but therole of the stress in the initiation and propagation stage is still not fully understood.Previous studies have shown that the scanning vibrating electrode technique (SVET) can be used to map pitting corrosion sites on austenitic stainless steels (SS) in nonstrained conditions. The present research looks to expand the scope of this technique, employing SVET analysis of strained and non-strained samples of 304 SS- in the annealed and thermally sensitised condition. Such samples were tested in 3 M and 4 M MgCl2 concentrations, aiming to obtain relevant data that can improvethe understanding of the role of stress in the initiation of pitting corrosion.As part of the experiments carried out, droplet tests were performed on annealed and sensitised samples under strained and non-strained conditions, determining that 4 M MgCl2 was the ideal concentration whereby spontaneous formation of pits in open circuit conditions was reproducibly observed. Subsequently, the samples were immersed in this chloride electrolyte and the localised corrosion behaviour was studied in-situ using the SVET. The current density maps obtained showed that applied strain can decrease the decay rate of anodic current density for the propagating pits compared with the un-strained surface. Additionally, these results were complemented with potentiodynamic polarisation, optical microscopy, scanning electron microscopy and height-depth microscopy, which showed morphologies and other relevant characteristics. The results obtained could open new research lines to investigate the role of stress in the initiation of SCC in nuclearcladding alloys.In a separate experiment, the localised corrosion characteristics of coupons consisting of a bespoke nuclear cladding alloy (20Cr/25Ni/Nb) electron beam welded to a simulant sensitised grain boundary alloy (45Fe/45Ni/10Cr) was carried out. The tests performed included potentiodynamic polarisation studies of the alloy, weld, and simulant grain boundary regions separately along with, SVET andSKP analysis of the test coupon as a whole. Spatially resolved SKP-derived maps determined the relative nobility of the cladding in comparison to the simulant alloy, and SVET studies showed that the weld joint was most susceptible to localised corrosion initiation under immersion conditions.
published_date 2024-04-08T15:46:36Z
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score 11.013395

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