Publication:
Systematic review of ultrasonic impact treatment parameters on residual stresses of welded non-sensitized versus sensitized aluminum-magnesium

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Authors
Fakhouri, Eid Faiz
Subjects
UIT
ultrasonic impact treatment
residual stress
aluminum-alloys
XRD
x-ray diffraction
AA5456
AA5083
electropolishing
metallography
sub-surface cracking
SCC
stress corrosion cracking
Advisors
Menon, Sarath
Brewer, Luke N.
Date of Issue
2015-03
Date
March 2015
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
This thesis focuses on the use of x-ray diffraction to measure residual stresses around welds in 5XXX series aluminum-alloys used in naval ship structures both in the laboratory and the field. Tensile residual stresses are commonly generated during welding and, in sensitized alloys, can cause stress corrosion cracking. Peening techniques, such as ultrasonic impact treatment (UIT), can mitigate and possibly reverse these tensile residual stresses. This research uses x-ray diffraction to measure residual stresses around welds in AA5456 after UIT, around welds in AA5083 installed on-board a U.S. naval combatant and in AA5083 after in situ surface preparation. In the AA5456, we examined the importance of UIT parameters such as peening amplitude and pin size. It was found that all combinations of UIT parameters produced significant compressive stress but that some combinations resulted in extensive subsurface intergranular cracking in the sensitized AA5456. Optimal UIT parameters for mitigating the production of subsurface cracking were determined. In the AA5083, we examined the effect of field-based in situ surface preparation on residual stress measurements. The use of a portable x-ray diffractometry system to experimentally measure the distribution of residual stresses in aluminum-alloy ship structures on U.S. Navy vessels has been successfully demonstrated.
Type
Thesis
Description
Series/Report No
Department
Mechanical and Aerospace Engineering
Mechanical and Aerospace Engineering (MAE)
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Identifiers
NPS Report Number
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Funder
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Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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