Title

A Study Of Phase Transformations During The Development Of Pressure-Composition-Isotherms For Electrodeposited Mg-Al Alloys

Keywords

Hydrogen storage; Mg-Al alloys; PCT curve; Phase transformation

Abstract

The evolution of microstructure during the pressure-composition-temperature (PCT) test at 350 °C for Mg-10at%Al and Mg-4at% alloy powders fabricated by electrodeposition as well as pure Mg powder were studied. The results of this study show that the starting microstructure of the Mg-10at%Al alloy powders consist mainly of the hcp-Mg phase. However, due to the rejection of Al by the MgH2 phase, a considerable amount of the Mg17Al 12 phase forms upon the initial hydrogenation stage. Consequently, this powder exhibits three transformational steps with the final microstructure consisting of MgH2 and fcc-Al phases. The dehydrogenation takes place at relatively high pressure by formation of the Mg17Al12 phase at the MgH2/fcc-Al interface. The hydrogen released diffuses through the interconnected fcc-Al/Mg17Al12 network to the surface. In contrast, Mg-4at%Al and pure Mg powders release hydrogen at a low pressure by the nucleation of the hcp-Mg phase on the surface. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Publication Date

1-1-2011

Publication Title

International Journal of Hydrogen Energy

Volume

36

Number of Pages

639-647

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.ijhydene.2010.09.083

Socpus ID

79451468774 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/79451468774

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