A Study of the Effects of Rare-Earth Elements
on the Microstructural Evolution and Deformation Behavior of Magnesium Alloys at Temperatures up to 523K
Materials Science and Engineering Seminar
Dr. Carl J. Boehlert
Department of Chemical Engineering and Materials Science
Michigan State University, MI
Abstract: Due to their high specific strength, lightweight magnesium (Mg) alloys are being increasingly used for applications, such as the automotive industry, where weight savings are critical. In order to develop new alloys and processing methods to achieve higher strength and better formability to compete with currently used metal alloys, it is important to understand the effects of alloying elements, processing, and temperature on the microstructure, mechanical properties, and the deformation behavior. In this work, a systematic investigation on the effects of Nd additions (0-1wt.%) and temperature (298-523K) on the microstructure and the activity of different deformation modes in as-cast and cast-then-extruded Mg-1Mn (wt.%) alloys were performed. The main findings of this work were that the microstructure, strength, and the distribution of the deformation modes varied significantly as a function of Nd content, temperature, and processing. An increase in the Nd content resulted in a weaker texture after extrusion in Mg-1Mn alloys. A combination of slip and twinning mechanisms controlled the tensile deformation in the extruded alloys at ambient temperatures. With an increase in temperature, the twinning activity decreased, and slip mechanisms dominated the deformation. The insights gained understanding the deformation behavior and microstructural evolution of RE-containing Mg alloys will be presented.
Bio: Dr. Boehlert received his B.S. degree in Agricultural and Biological Engineering at Cornell University. Boehlert earned M.S. and Ph.D degrees in Materials Science and Engineering at the University of Dayton, where he studied the physical metallurgy of advanced titanium alloys and their composites. After leaving Dayton, Boehlert worked for two years as a postdoctoral fellow in the Mechanical Engineering Department of the Johns Hopkins University. There he worked on the physical metallurgy of TiAl intermetallic alloys. Boehlert then joined Los Alamos National Laboratory (LANL) as a postdoctoral research associate within the Nuclear Materials Technology Division, where he worked on the physical metallurgy of plutonium and cerium alloys. In September of 2001, Boehlert joined the New York State College of Ceramics at Alfred University as an assistant professor. Boehlert then joined the Department of Chemical Engineering and Materials Science in the College of Engineering at Michigan State University as an assistant professor in 2005. He is a recipient of a National Science Foundation (NSF) CAREER Award and a Department of Energy (DOE) Presidential Early Career Award for Science and Engineering (PECASE). His research interests include materials engineering; materials sciences; metallurgy; electron backscatter diffraction; intermetallics electron microscopy; metal matrix composites; titanium alloys and composites; mechanical behavior. His research group is concentrating on understanding the deformation behavior of hexagonal close packed metals, in particular, titanium and magnesium alloys, under extreme environments.
Friday, February 15 at 3:00 pm to 4:00 pm
Minerals and Materials Engineering Building (M&M), 610
1400 Townsend Drive, Houghton, MI 49931