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dc.contributor.advisorNordlien, Jan Halvor
dc.contributor.authorKishan Roodbari, Marzieh
dc.date.accessioned2016-02-05T15:00:40Z
dc.date.available2016-02-05T15:00:40Z
dc.date.created2015-06-30
dc.date.issued2015
dc.identifierntnudaim:13530
dc.identifier.urihttp://hdl.handle.net/11250/2377272
dc.description.abstractCorrosion by pitting in aluminum alloys is a very complex process that can be affected by various factors such as chemical composition and microstructure of the alloys. The electrochemistry and distribution of second phases populating the alloy are the main factors that significantly influence the corrosion of aluminum alloys. The purpose of the present work is to contribute to a deeper understanding of how the chemical composition and microstructure affect the ability of an aluminium alloy to form a passive layer and its susceptibility to localized corrosion. To carry out the experiment, samples of alloys 3003, 5049, 6061, and 6063 were prepared. The open circuit potential transient technique was utilized to investigate the corrosion potential of alloys under study. The ability of alloys to form the passive layer and the corrosion parameters such as corrosion potential were determined using potentiodynamic polarization measurement. In this study, the corrosion behvaiour of alloys was explored as a function of time using the salt spray test. For each type of alloy, we considered 26 samples, prepared from tubes, and tested in a salt spray chamber in the duration of 49 days. At specified intervals, two samples of each alloy were taken out from the chamber. The type of corrosion and the corrosion rate were investigated through this test. As pitting is the main corrosion process, the depth of ten deepest pits were measured using optical microscopy. Also, the cross section of the deepest pit was analyzed to see if the alloy is susceptible to intergranular corrosion. Statistical analysis was carried out in order to investigate the variation of corrosion rate during exposure and to predict the lifetime of a component. In particular, the Extreme Value theory, the Gumbel distribution, was employed to plot the probability paper of the extreme pit depth occurrence. In addition, the Gumbel distribution theory was utilized to extrapolate data to longer exposure times.
dc.languageeng
dc.publisherNTNU
dc.subjectLight Metals, Silicon and Ferroalloy Production
dc.titleEffect of Microstructure on the Performance of Corrosion Resistant Alloys
dc.typeMaster thesis
dc.source.pagenumber72


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