Corrosion Behavior of Ultrafine-Grained 5083 Al
Authors:Yanting Li, Ming-Je Sung
Mentor:Farghalli Mohamed, Professor of Chemical Engineering and Materials Science, University of California Irvine
In 2002, the National Association of Corrosion Engineering published a study that stated the direct cost of corrosion was estimated to be about 276 billion US dollars per year, which is approximately 3.1% of the national Gross Domestic Product. Therefore, it is higher desirable to improve the corrosion resistance of materials in commercial applications. In this study, Aluminum-5083 was selected to determine the relationship between grain sizes and corrosion resistance by contrasting ultra-fine grained (UFG, 100 nm-500 nm in size) aluminum to its commercial counterpart, coarse grained aluminum (CG, 500 nm-10 μm in size). Initial images of both the UFG and CG Al-5083 were taken using Scanning Electron Microscopy and Optical Microscopy, respectively. Grain size analysis was performed to confirm that the materials were indeed UFG and CG. Next, a salt spray test was performed on both UFG and CG Al-5083 to investigate the effect of grain size on corrosion resistance. The average grain size of the UFG Al-5083 was measured to be 244 nm and 303μm for the CG Al-5083. Furthermore, the salt spray test results revealed that UFG Al-5083 has better resistance to corrosion than CG Al-5083. Understanding the factors that influence the corrosion resistance of materials, particularly Al-5083, will help us produce superior materials that have an even longer service life in harsh (corrosive) environments.