Four Point Bend Testing of Shipboard Sensitized Aluminum-Magnesium Alloy to Characterize Effect of Surface Ultrasonic Shot Peening on Stress Corrosion Cracking

Simple item page
dc.contributor.advisorZupan, Marc
dc.contributor.authorVail, Caroline
dc.contributor.departmentMechanical Engineering
dc.contributor.programEngineering, Mechanical
dc.date.accessioned2021-09-01T13:55:59Z
dc.date.available2021-09-01T13:55:59Z
dc.date.issued2019-01-01
dc.description.abstractHigh strength aluminum-magnesium (Al-Mg) alloys are commonly used in naval structural applications but sensitization of their microstructures can lead to stress corrosion cracking (SCC). Sensitized microstructures contain ? phase at the grain boundaries that is anodic to the Al matrix. In order for SCC to occur, a susceptible microstructure, corrosive environment, and stresses must be present. Surface treatment methods that impart compressive stresses are used to combat the harmful tensile stresses that lead to SCC. Ultrasonic shot peening is a repeatable surface treatment method that imparts compressive stresses with a reduced surface roughness in comparison to other surface treatment methods. This study aims to understand the effect of ultrasonic shot peening on the meso- through micro-scales of SCC on a high strength Al-Mg alloy, 5456- H116 Al, under in-service comparable conditions. Shipboard and laboratory sensitized 5456-H116 Al with and without ultrasonic shot peening is tested in static four-point bending in an alternate immersion artificial seawater environment. Ultrasonic shot peened surfaces are characterized for compressive stress using hole drilling, surface texture using confocal microscopy, and grain deformation using electron backscatter diffraction (EBSD). Quantitative data from the bent beam testing differentiates between the time to start cracking and the time to reach full failure. Failed four-point bend specimens are examined using optical microscopy and X-ray computed tomography (X-ray CT) at the meso- and macro-scales to connect the flexural stress state to resulting SCC shape and branching behavior. Three-dimensional (3D) characterization of the micro-scale branching crack using X-ray CT front provides insight into SCC growth mechanisms and microstructure influenced localized corrosion events.
dc.formatapplication:pdf
dc.genredissertations
dc.identifierdoi:10.13016/m2kpa0-7zvv
dc.identifier.other12093
dc.identifier.urihttp://hdl.handle.net/11603/22931
dc.languageen
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Mechanical Engineering Department Collection
dc.relation.ispartofUMBC Theses and Dissertations Collection
dc.relation.ispartofUMBC Graduate School Collection
dc.relation.ispartofUMBC Student Collection
dc.sourceOriginal File Name: Vail_umbc_0434D_12093.pdf
dc.subject5456 aluminum magnesium
dc.subjectNavy
dc.subjectsensitization
dc.subjectstress corrosion cracking
dc.subjectsurface treatment
dc.subjectX-ray computed tomography
dc.titleFour Point Bend Testing of Shipboard Sensitized Aluminum-Magnesium Alloy to Characterize Effect of Surface Ultrasonic Shot Peening on Stress Corrosion Cracking
dc.typeText
dcterms.accessRightsAccess limited to the UMBC community. Item may possibly be obtained via Interlibrary Loan thorugh a local library, pending author/copyright holder's permission.
dcterms.accessRightsThis item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu

Files

Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Vail_umbc_0434D_12093.pdf
Size:
194.39 MB
Format:
Adobe Portable Document Format
Download

Collections

UMBC Theses and Dissertations
UMBC Graduate School
UMBC Mechanical Engineering Department
UMBC Student Collection