Solidification Pathways of Alloys in the Mg-Rich Corner of the Mg-Al-Ba Ternary System
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An experimental investigation of the solidification reactions and microstructures of alloys in the Mg-rich corner of the Mg-Al-Ba ternary system has been conducted. Four distinct exothermic reactions involving the formation of α-Mg, Mg17Ba2, Mg17Al12, and a fourth phase designated as τ were observed and their onset temperatures were recorded as functions of composition. Using compositional and microstructural analysis, the Mg17Ba2 intermetallic was found to have significant solubility of Al, up to 20 at. pct. The solidification pathways of the investigated alloys involved both a Class I and Class II equilibrium reaction. A flow block diagram that outlines the observed solidification reactions is presented and discussed in reference to cast microstructures.
KeywordsDifferential Scanning Calorimetry Solidification Reaction Heat Flow Curve Mg17Al12 Phase Cast Microstructure
The authors would like to acknowledge the financial assistance of the National Science Foundation under award number DMR-0845868 and the Department of Energy Office of Science Graduate Fellowship Program, administered by ORISE-ORAU (Contract #: DE-AC05-06OR23100).
- 1.C. Blawert, N. Hort and K.U. Kainer: Trans. Indian Inst. Met., 2004, vol. 57, pp. 397-408.Google Scholar
- 12.M.O. Pekguleryuz, E. Baril, P. Labelle and D. Argo: J. Adv. Mater., 2003, vol. 35, pp. 32-38.Google Scholar
- 16.T. Tsukeda, R. Uchida, K. Saito, M. Suzuki, J.-i. Koike, K. Maruyama, and H. Kubo: in Magnesium Alloys and their Applications, Wiley, Weinheim, 2006, pp. 47–52.Google Scholar
- 19.H. Okamoto: Desk Handbook: Phase Diagrams for Binary Alloys, ASM International, Materials Park, 2010.Google Scholar
- 25.W.M. Haynes and D.R. Lide: CRC Handbook of Chemistry and Physics, 92 ed., CRC Press, Boca Raton, 2011.Google Scholar
- 32.H. Okamoto: J. Phase. Equilib., 1998, vol. 19, pp. 598–98.Google Scholar