Established Materials Technology: Front Page
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JOM Spotlight on Magnesium Fundamental Research
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By Lynne Karabin, TMS Community Moderator
Posted on:
8/2/2007...
" . . . TMS is recognized as the global light metals community's preeminent forum for the presentation of magnesium science and technological issues."
Randy S. Beals, et. al. JOM, August 2007, pp. 39–42.
Fundamental research on magnesium is highlighted in the August 2007 issue of JOM. This topic begins with a paper by Beals, Cam Tissington, Xinmin Zhang, Karl Kainer, Joe Petrillo, Mark Verbrugge, and Mihriban Pekguleryuz titled "Magnesium Global Development: Outcomes from the TMS 2007 Annual Meeting." These authors summarized the presentations of the first magnesium globalization plenary session given at the TMS 2007 Annual Meeting in Orlando, Florida, on February 26, 2007. Topics covered include:
- Global Supply System
- Chinese Production and Applications
- European Advances in Manufacturing Processes
- Automotive Applications
- The Value of Lightweighting Vehicles
- Alloy Development and Applications
An important theme developed in this overview paper is the fact that corrosion and wrought magnesium processing remain areas of concern.
The second paper, contributed by Beals, Zi-Kui Lui, J. Wayne Jones, P.K. Mallick, Daryoush Emadi, David Schwam, and Bob R. Powell, describes the fundamental research currently supported by the Magnesium Powertrain Cast Components (MPCC) Project, which is a jointly sponsored effort by the U.S. Department of Energy and the U.S. Automotive Materials Partnership (USAMP). Five areas are covered: phase equilibrium and computational thermodynamics, creep deformation mechanisms, corrosion, hot tearing, and alloy recycling. Notable results include:
- Penn State University researchers have demonstrated the ability to predict thermodynamic data, which are needed to create high-quality thermodynamic databases, yet are very expensive to measure.
- University of Michigan (Ann Arbor, Michigan) researchers have studied the dislocation substructures that develop during creep and have related their observations to bolt load retention behavior for several creep-resistant alloys.
- University of Michigan-Dearborn researchers have evaluated the suitability of five types of corrosion tests in order to determine aqueous corrosion rates for eleven different magnesium alloys and found the titration method to be the most repeatable.
- CANMET (Ontario, Canada) researchers have shown that Ca additions to Mg-5Al reduce the hot tearing susceptibility by increasing the amount of interdendritic liquid, which improves interdendritic feeding and helps to accommodate strain and heal cracks during solidification.
- Case Western Reserve University (Cleveland, Ohio) researchers have reviewed current recycling technologies and have proposed topics for attention.
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The AE44 Mg alloy engine cradle used in the GM Corvette. Photo is from "Magnesium Global Development: Outcomes from the TMS 2007 Annual Meeting" by Beals et al., August 2007 JOM. |
The third paper, "Stress Corrosion Cracking in Magnesium Alloys: Characterization and Prevention," by N. Winzer, A. Atrens, W. Dietzel, G. Song, and K.U. Kainer, addresses transgranular stress corrosion cracking (TGSCC) of AZ91. Two methods for measuring TGSCC are evaluated, and the authors propose a model to predict cracking rates, making recommendations on how to avoid stress corrosion cracking.
In the final paper, "The Equal Channel Angular Processing of Magnesium and Magnesium Alloy Powders," M. Moss, R. Lapovok, and C.J. Bettles demonstrate that equal channel angular processing (ECAP) can produce compacts of sufficient density and green strength. Their studies have broad implications for alloy development as the ECAP route for compacting powders allows consideration of elements that would form deleterious phases if added in the molten state.
TMS members can view all of these articles on-line via Page Turning JOM. To view, members must log in using the username and password boxes at the top of the page.
Want more information on recent progress on magnesium research? Please see Magnesium Technology 2007 for papers presented at the TMS 2007 Annual Meeting.
Want more information on magnesium fundamentals? Please visit the Magnesium Community Digital Resource Center for background information, primers and recommended resources.
For other recent spotlight stories, please visit the Archive tab.
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