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Summer 2008 Seminar
June 30 at 3:30 p.m., Room 184 Watts Hall
Kinga Unocic
PhD Candidate advised by Dr. Michel Mills
Department of Materials Science and Engineering
The Ohio State University
Structure-Composition-Property Relationships in 5xxx Series Aluminum Alloys
Abstract
Al-Mg alloys are well suited for marine applications due to their low density, ease of fabrication, structural durability, and most notably resistance to corrosion. The purpose of this study is to investigate the effects of alloying additions, mechanical processing and heat treatments on the development of grain boundary phases that have an effect on intergranular corrosion resistance (IGC). Through modification of the standard AA5083 composition with extra additions of Cu and Zn and in conjunction with a long sensitization heat treatment (in excess of 1000 hrs at 165°C) it is possible to form a corrosion resistance modified t-phase along grain boundaries. From an economical standpoint it is too costly to heat treat an alloy for such a long period of time and therefore an alternative method of producing a corrosion resistant alloy has been explored. Cu, Zn, and Si modified compositions were produced and were subjected to a high degree of cold work and shorter sensitization times. Following ASTM G67 intergranular corrosion testing and a detailed microstructural characterization, an optimal composition and processing condition that yielded the best intergranular corrosion resistance was determined. The microstructural development that led to these findings and issues with TEM sample preparation will be discussed in detail.
Bio
Kinga A. Unocic is a Ph.D. student in the Materials Science and Engineering Department at the Ohio State University working with Professors Glenn Daehn and Michael Mills. Originally from Oswiecim, Poland, she graduated from AGH-University of Science and Technology in Krakow, Poland, in 2002 with a MS degree in Metallurgy, where she also received an award for scholar athlete of the year in 1998/99. She was a visiting research scholar at Lehigh University in Bethlehem, PA, where she conducted research on extrusion of 6XXX series aluminum alloys with the Institute for Metal Forming group under the guidance of Professor Wojciech Misiolek. Her current research is focused on alloy development of 5XXX series aluminum alloys for improved intergranular corrosion resistance and her research interests include the use of materials characterization techniques (SEM, TEM, FIB) to explore the relationship between microstructure, corrosion, and mechanical properties.
Conference Presentations
- K.A. Unocic, Challenges in Preparing Aluminum Alloys for Grain Boundary Characterization, Microscopy and Microanalysis, Albuquerque New Mexico (2008). (Invited)
- K.A. Unocic, P. Kobe, M.J. Mills and G.S. Daehn; Effect of Grain Size and Substructure on Sensitization in 5083 Al Alloys, TMS Annual Meeting, New Orleans Louisiana (2008).
- K.A. Unocic, P. Kobe, M.J. Mills and G.S. Daehn; Grain Boundary Precipitate Modification for Improved Intergranular Corrosion Resistance, 10th International Conference ICAA10 (2006).
- K.A. Unocic, M.J. Mills, G.S. Daehn, and P. Kobe, Microstructural Analysis of 5XXX Series Aluminum Alloys Modified for Optimal Strength and Corrosion Resistance, Microscopy and Microanalysis, Honolulu HI (2005).
Conference Poster Presentation
- K.A. Unocic, L. Kovarik, P. Kobe, M.J. Mills and G.S. Daehn, Identification of Grain Boundary Phases in Modified AA5083, The Gordon Research Conference on Physical Metallurgy, Plymouth, July 23-28, 2006.
